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 [Search a list of Patent Appplications for class 137]   CLASS 137,FLUID HANDLING
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SECTION I - CLASS DEFINITION

This is the residual class for fluid material handling, and takes processes, systems, combinations, subcombinations and certain elements pertaining thereto not otherwise classified.

Fluid materials include gas and liquids primarily, but the handling of other flowable materials, as fluent granular solids, is also found.

Handling for this class comprises the transfer of fluent material by flow, as by confining, directing, causing and/or controlling the flow, and includes making the material available for flow or separating a smaller from a larger body of fluid material, as by tanks, containers, receivers, traps, etc., or pipes or conduits, with or without siphons, pumps, pressure or displacing fluids or other flow imparting means.

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

The class is divided into two groups, subclasses 1+ for processes, and subclasses 38 to 616 for automatic or condition change responsive devices, special types and combinations of the necessary elements of the class with the subject matter of other classes or with features added to perfect the operation of the material handling means, and the more complex devices of the class generally grouped under the title "systems." Class 251, Valves and Valve Actuation, provides for valves and valve actuation not otherwise classified. Subclasses 777 to 802 comprise subcombinations and elements pertaining to fluid handling not particularly related to any of the special types and not otherwise classified.

Automatic or condition change responsive systems and devices of this class are discussed more at length in (1) Automatic Control below, (2) Plural Valves, and (3) Valve Actuation.

(1) AUTOMATIC CONTROL

Devices and systems in which the presence or absence of, or a change in, a condition is sensed and control exercised as a result thereof are commonly called automatic, and in this class form the basis of a number of "special type" and general categories.

Line condition change response refers to control exercised over the material being handled in the system as a result of a change in the condition of that material, as temperature, quantity, pressure or rate of flow. Condition change response does not include the mere fact of flow or those fluid pressure operated devices where change does not affect the operation of the device, nor those where the flow is changed by external means for the purpose of causing operation of the control means or with that result.

Combinations of an automatic valve with a nonautomatic valve have been excluded for line condition change responsive groupings because the system comprising such combinations is not primarily automatic.

Fluid actuated or retarded valves which have not been considered automatic even though they depend on the presence of fluid flowing in the line, and have been classified in the following subclasses in Class 251; are (1) fluid actuated valves with compulsory cut-off after a flow period (subclasses 15+), (2) dash-pot or fluid controlled timers and retarders for valves, operating fluid for which is derived from the line controlled (subclasses 50+).

The following groups of subject matter in this class are wholly or partly of automatic or closely related types. In each instance the search notes in the definitions of the particular subclasses referenced in Subclass References of the Current Class, below, should be consulted for related art.

Atmospheric

Boiler (see temperature)

Combustion (see temperature)

Discriminating Valves (see level response).

Failure Responsive and Testing Devices

Freeze (see Temperature).

Heating (see Temperature)

Inertia or Position Change

Level Response or Maintenance, Floats, Gravitating Tanks, including: (A) By pressure connection at liquid level; (B) By gravitating vessel; and (C) By floats - This class is the generic place for floats, per se, and systems controlled by floats are classified in various appropriate groups, the subclasses in Subclass References to the Current Class provide especially for float control or operation.

Line Condition Change Response - See the definition, second paragraph of this section, and listings under Plural heading below

Periodic or Cyclic

Plural - For a discussion of plural valves as such, see following section (4). In this category, plural flow controllers, valves, or condition responsive means may be (A) plural valves controlling different flows, (B) plural valves controlling the same flow, (C) one valve responding to changes in plural conditions, or (D) plural valves each responding to a different condition change. Subclass References to the Current Class includes subclasses references to the following: (1) Plural Flows; (2) Plural Condition Responses; (3) Plural Controls, One Condition Responsive -Where the controls are separate valves controlling the same flow and one is not automatic or line condition responsive the patent is excluded from line condition responsive categories. See section 2, definitions. Such patents may appear in the earlier special type groups of subclasses, however:

Pressure Modulating

Pump

Safety cut-offs - For resetting operations see (3) Manual Control, Resetting, and Adjusting Devices, especially the subclass references to Cut-offs With Resetting.

Speed Responsive Control

Temperature. (See Boiler, Combustion)

(2) PLURAL VALVES

Control means for plural flow paths comprising a single movable body having plural seats or plural port obstructing positions have been classified as multiway valve units in subclasses 625+. Valves associated with dispensers have been classified in Class 222, Dispensing. See especially the Search Notes in the appropriate subclasses of these classes and in the main class definitions, as well as the Search Notes to the subclasses listed below.

In Class 137 devices for controlling plural flows have been regarded as comprising a system (1) if additional flow confining means was claimed to a greater extent than as a mere mounting for the valves, (2) if some definite significant relation between fact of flow and/or the direction of flow in the plural flow paths exists, or (3) if one or more conduits or passages have two or more valves or cut-off devices which function to control the flow of the fluid by means of the valves. Some plural flow path controls of various automatic or condition change responsive types are also found in the earlier subclass groups, but on that basis rather than as systems in and of themselves.

Plural valves having a common means for simultaneous or alternating actuation, are for the most part in appropriate subclasses under subclass 561. Some valves, because of motor or complex mechanical actuation, have been classified in Class 251, Valves and Valve Actuation, under the type of actuation.

For plural automatic or condition responsive valves, see (1) Automatic Control, "Plural Condition Responses", above and the associated references in Subclass References to the Current Class.

For plural valves, one automatic or condition responsive and one or more mechanically or manually actuated, see section for Automatic Control, Plural Controls, "One Condition Responsive", above and the associated references in Subclass References to the Current Class.

(3) MANUAL CONTROL, RESETTING AND ADJUSTING DEVICES

See section for Automatic Control, Plural Controls, One Condition Responsive, above for notes on manual control of valves which are also condition responsive and for manual valves combined with automatic or condition responsive valves.

The term "manual" in some instances includes nonautomatic valve actuation of other types, as by mechanical movements or even motors.

The term "control" or "actuation" as applied to the operation of valves does not include the resetting of valves which are either condition responsive or trip actuated to move from a preset position and which do not return to that position when the operating force is removed or reversed, but require intervention of an external independent agency to restore them to their set position. Mere adjustment of bias, spacing, seating or actuator connection of a valve is not included in these terms.

(A) Flow Control or Valve Actuation - See references to (1) Automatic Control, "Plural Controls, One Condition Responsive", for manual and automatic actuation of valves, and also (2) "Plural Valves," for plural valves, including actuation.

(B) Cut-Offs with Resetting - Also see references to (1) Automatic Control, "Safety Cut-offs."

(C) Adjustment

SECTION III - SUBCLASS REFERENCES TO THE CURRENT CLASS

SEE OR SEARCH THIS CLASS, SUBCLASS:

2+,for processes of controlling a flow by condition or characteristic of a fluid, especially subclasses 3+ for mixture control. (Automatic Control - Line Condition Change Response).
3+,processes of mixing plural fluids of diverse characteristics or conditions. (Automatic Control - Plural Flows).
6,processes of mixing controlled by heat of combustion of mixture. (Automatic Control - Combustion).
8,processes for producing uniform flow. (Automatic Control - Pump).
13,processes for affecting flow by the addition of energy (Automatic Control - Pump).
11,Processes of regulating boiler feed water level.(Automatic Control - Boiler).
11,processes of regulating boiler water level. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks).
10,processes of flow control by speed of fluid. (Automatic Control - Speed Responsive Control).
13,processes of affecting flow by the addition of heat. (Automatic Control - Temperature).
38+,for change of altitude as reflected by change in air pressure, see subclass 81. (Automatic Control - Inertia or Position Change).
39,control by change of position or inertia of system with second control. (Automatic Control - Plural Controls, One Condition Responsive).
39,control by change or position or inertia of system with second control. (Automatic Control - Plural Condition Responses).
40+,marine governors. (Automatic Control - Combustion).
49,speed responsive valve control with manual control. (Automatic Control - Plural Controls, One Condition Responsive).
76,and 77, heat destructible or fusible control elements with external closing means. (Automatic Control - Plural Controls, One Condition Responsive).
80,atmospheric temperature change responsive control with additional diverse control. (Automatic Control - Plural Controls, One Condition Responsive).
41,float controlled marine governors. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
47+,speed responsive valve control. (Automatic Control - Speed Responsive Control).
43,vent closing in overturned containers. (Automatic Control - Safety cut-offs).
50,and 57, excess speed responsive controls. (Automatic Control - Safety cut-offs).
50,and 51+, speed responsive control with other condition responsive valve control. (Automatic Control - Plural Condition Responses).
50,and 57, excess speed cut-offs. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
52,speed responsive valve control with governor drive failure control. (Automatic Control - Failure Responsive and Testing Devices).
59+,freeze condition responsive safety cut-off. (Automatic Control - Temperature).
65+,combustion failure responsive safety cut-offs for burners. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
65+,combustion failure responsive fuel safety cut-offs for burners. (Automatic Control - Boiler).
65+,combustion failure responsive fuel safety cut-off for burners. (Automatic Control - Temperature).
65+,combustion failure responsive fuel safety cut-offs for burners. (Automatic Control - Combustion).
65+,combustion failure responsive fuel safety cut-off for burners. (Automatic Control - Safety cut-offs).
65+,combustion failure responsive cut-off for burner fuel. (Automatic Control - Failure Responsive and Testing Devices).
67+,frangible, soluble, deformable or fusible control elements, the failure of which caused operation of safety means. (Automatic Control - Failure Responsive and Testing Devices).
67+,destructible or deformable element control, especially subclasses 72+, heat destructible or fusible. (Automatic Control - Combustion).
72+,heat destructible or fusible element control. (Automatic Control - Temperature).
73,heat destructible of fusible element control with second sensing means. (Automatic Control - Plural Condition Responses).
75+,heat destructible or fusible safety cut-offs. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
80,atmospheric temperature change responsive control with additional diverse control. (Automatic Control - Plural Condition Responses).
82+,pressure modulating relays or followers. (Automatic Control - Pressure Modulating).
98+,self-proportioning flow systems. (Automatic Control - Plural Condition Responses).
75+,heat destructible or fusible safety cut-off elements. (Automatic Control - Safety cut-offs).
78+,for atmospheric condition change responsive controls. (Automatic Control - atmospheric).
79+,atmospheric temperature change responsive control. (Automatic Control - Temperature).
87.01+,plural flows. (Automatic Control - Line Condition Change Response).
87.01+,self-proportioning or correlating systems. (Automatic Control - Plural Flows).
88+,apparatus for controlling mixtures. (Automatic Control - Line Condition Change Response).
96+,control of pump-motive fluid by level of pumped liquid. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks).
98+,self-proportioning flow systems. (Automatic Control - Line Condition Change Response).
90,mixture condition maintaining or sensing by temperature or heat content. (Automatic Control - Temperature).
94,fuel controlled by boiler or water system condition. (Automatic Control - Temperature).
94,fuel controlled by boiler or water system condition.(Automatic Control - Boiler).
94,fuel controlled by boiler or water system condition. (Automatic Control - Combustion).
101.25+,for self-proportioning systems with liquid level sensing means. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks).
103+,vacuum or suction pulsator type systems. (Automatic Control - Periodic or Cyclic).
106,reversing or 4-way valve systems. (Automatic Control - Periodic or Cyclic).
109+,self-controlled branch flow systems. (Automatic Control - Line Condition Change Response).
115.03+,by-pass or relief responsive to change in rate or main line flow in self-controlled branch systems. (Automatic Control - Speed Responsive Control).
129,163, 190, 401, and 404, sinking or bucket type floats. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By gravitating vessel).
120,161, 162+, 189, 402, and 403+, especially subclass 408, gravitating tanks. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By gravitating vessel).
120,and 122, filling successive tanks by float controlled receiver. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
129,sinking float operated siphons. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
129,163, 190, 401, and 404, for sinking or bucket type floats: see level response. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
131,float controlled discharge from a siphon to a receiver. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
132+,periodic or accumulation responsive siphon discharge. (Automatic Control - Periodic or Cyclic).
133,periodic siphons with manual control. (Automatic Control - Plural Controls, One Condition Responsive).
135,float operated inlet for siphons. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
137,for float operated vents for trapped air in a siphon. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
154+,diverse fluid containing pressure systems, especially subclass 155, gas lift valves for wells, 180, 183, 199, 204, 213+. (Automatic Control - Line Condition Change Response).
154+,155, 156+, for diverse fluid containing pressure systems which repeatedly discharge gas and/or liquid upon accumulation thereof. (Automatic Control - Periodic or Cyclic).
154+,diverse fluid containing pressure systems, especially subclasses 156+, gas pressure discharge of liquid feed traps to receivers under pressure and 173+, plural discriminating outlets for diverse fluids in pressure systems. (Automatic Control - Plural Flows).
156+,gas pressure discharge of liquid feed traps to boilers.(Automatic Control - Boiler).
158,gas pressure discharge of liquid feed trap controlled by level in boiler or receiver. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By pressure connection at liquid level).
169,manual control of gas pressure in discharging liquid feed traps to boilers. (Manual Control, Resetting And Adjusting Devices - Flow Control or Valve Actuation).
171+,fluid separating traps or vents. (Automatic Control - Boiler).
171+,accumulation responsive fluid separating traps and vents. (Automatic Control - Periodic or Cyclic).
163,165+, 185+, 192+, and 202, for float control in diverse fluid containing pressure systems. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
171+,fluid separating traps and vents. (Automatic Control - Discriminating Valves).
173+,plural discriminating outlets for diverse fluids in pressure systems. (Automatic Control - Plural Condition Responses).
183+,199+, for accumulation responsive gas pressure discharge of liquid feed traps to receivers under pressure. (Automatic Control - Periodic or Cyclic).
184,plural successively opened discriminating fluid responsive valves for liquid in diverse fluid containing pressure systems. (Automatic Control - Plural Condition Responses).
185+,for gas collecting floats, e.g., inverted bucket type. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
213+,liquid level responsive gas vent or whistle.(Automatic Control - Boiler).
213+,liquid level responsive gas vent or whistle. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By pressure connection at liquid level).
215+,back flow prevention by vacuum breaking. (Automatic Control - Line Condition Change Response).
214,high and low level responsive gas vents or whistles for diverse fluid containing pressure systems. (Automatic Control - Plural Condition Responses).
218,back flow preventing air vent in liquid line with coacting valve in liquid flow path. (Automatic Control - Plural Condition Responses).
220,line condition change responsive valves of the Larner-Johnson type. (Automatic Control - Line Condition Change Response).
223+,tire filling chuck and stem type connectors. (Automatic Control - Plural Controls, One Condition Responsive).
224+,pressure-responsive pressure-control means for tire inflation devices. (Automatic Control - Pump).
226,coaxial inflation and relief valves for tire inflation with pressure-responsive pressure-control means. (Automatic Control - Plural Condition Responses).
229,selectively connected gauge and inflow or relief passages in tire inflation devices. (Plural Valves).
230,stem attached relief valves for tires. (Automatic Control - Line Condition Change Response).
238+,steam sterilizing. (Automatic Control - Temperature).
255+,plural tanks or compartments with parallel flow. (Plural Valves).
270through 270.5, for a convertible unit orientable in a single location between plural positions.
271,for convertible units interchangeable between alternate locations.
274,286+, 614+, and 616, valve actuators comprising movable flow pipes. (Manual Control, Resetting And Adjusting Devices - Flow Control or Valve Actuation).
285,299 and 300, serial valves in hydrants. (Plural Valves).
289,balanced valves in hydrants. (Plural Valves).
290,291+, and 298, hydrant valve actuators. (Manual Control, Resetting And Adjusting Devices - Flow Control or Valve Actuation).
297,hydrant casing with heater. (Automatic Control - Temperature).
301+,hydrant protection against freezing. (Automatic Control - Temperature).
309+,regenerative furnace type reversing valves. (Automatic Control - Combustion).
309,regenerative furnace type reversing valves. (Plural Valves).
310,regenerative furnace type reversing valves with cooling means. (Automatic Control - Temperature).
334+,heating or cooling of fluid handling systems. (Automatic Control - Temperature).
334+,heating, especially subclasses 335+, burner type. (Automatic Control - Combustion).
345+,locomotive associated systems. (Automatic Control - Combustion).
344+,heating, especially subclasses 335+ burner type. (Automatic Control - Boiler).
346,locomotive boiler or steam dome associated systems. (Automatic Control - Boiler).
386+,liquid level responsive or maintaining systems.(Automatic Control - Boiler).
389,liquid level responsive systems with a second diverse control. (Automatic Control - Plural Condition Responses).
390,liquid level responsive systems with manual control. (Automatic Control - Plural Controls, One Condition Responsive).
391,control of both inflow and outflow of a tank by liquid level responsive means. (Automatic Control - Plural Condition Responses).
393,liquid level control or maintenance. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By pressure connection at liquid level).
396+,for self-emptying tanks responsive to level of accumulated liquid. (Automatic Control - Periodic or Cyclic).
397,398+, 401, 404, and 409+, for float control in liquid level responsive or maintaining systems. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
399,low level safety cut-off of tank outflow. (Automatic Control - Safety cut-offs).
399,float operated low level safety cut-offs. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
405,oil burner fuel overflow preventing safety cut-offs operated by accumulated fluid weight. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
405,oil burner fuel overflow preventing safety cut-offs operated by weight of accumulated fuel. (Automatic Control - Combustion).
436+,float arm operated valves with restrictors, e.g., silencers. (Automatic Control - Plural Controls, One Condition Responsive).
456+,line condition change responsive safety cut-offs requiring resetting. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
475+,pop valve with adjustable choke (Automatic Control - Plural Controls, One Condition Responsive).
481,combustion engine induction type governor with manual modifier. (Automatic Control - Plural Controls, One Condition Responsive).
495,line condition responsive valves with a separate connected fluid reactor surface and manual or external control for the valve. (Automatic Control - Plural Controls, One Condition Responsive).
479+,combustion engine induction type governors. (Automatic Control - Combustion).
457,safety cut-offs responding to thermal conditions and requiring resetting. (Automatic Control - Temperature).
458,and 459+, line condition change responsive valves of the safety cut-off type responding to velocity or rate of flow. (Automatic Control - Speed Responsive Control).
458,safety cut-offs responsive to both high and low pressure or velocity. (Automatic Control - Plural Condition Responses).
482,combustion engine induction type. (Automatic Control - Plural Condition Responses).
493,line condition change responsive valves of the bidirectional type governor with suction compensator. (Automatic Control - Plural Condition Responses).
456+,line condition change responsive safety cut-off valves requiring resetting. (Automatic Control - Safety cut-offs).
455+,line condition change responsive valves, especially 469+, pop valves. (Automatic Control - Boiler).
486+,for pilot or servo-controlled valves responsive to change in rate of fluid flow. (Automatic Control - Speed Responsive Control).
497+,for valves with separate connected fluid reactor surface responsive to change in rate of fluid flow. (Automatic Control - Speed Responsive Control).
468,line condition thermal change responsive valves. (Automatic Control - Temperature).
482,combustion engine induction type governor with suction compensator. (Automatic Control - atmospheric).
455+,line condition change responsive valves. (Automatic Control - Line Condition Change Response).
506,and 512+, plural line condition change responsive valves. (Automatic Control - Plural Condition Responses).
522+,for safety valves with testing means. (Automatic Control - Failure Responsive and Testing Devices).
524,for a valve (i.e., check valve, etc.) that directly responds to a change in line condition having a bias adjustment indicator.
530,for a reciprocating valve (i.e., check valve, etc.) that directly responds to a change in line condition having a bias fixed or adjusted by a cam.
531,for a reciprocating valve (i.e., check valve, etc.) that directly responds to a change in line condition having a bias fixed or adjusted by varying its lever.
533+,position or extent of motion indicators for fluid handling apparatus. (Manual Control, Resetting And Adjusting Devices - Adjustment).
571+,plural tanks or compartments connected for serial flow. (Plural Valves).
583,systems with plural openings, one a gas vent or access opening. (Plural Valves).
586,access opening interlock with outlet valve actuator. (Manual Control, Resetting And Adjusting Devices - Flow Control or Valve Actuation).
595,601, 607, 609, 888+, and 896+, plural valves with common operator in plural flow paths, either separate or branching. (Plural Valves).
596,stop and waste systems. (Plural Valves).
598,hill holders for hydraulic brake lines. (Automatic Control - Plural Controls, One Condition Responsive).
606,and 861+, flow control means for plural flows in distribution systems. (Plural Valves).
613+,distribution systems comprising a single flow path with plural serial valves and/or closures. (Plural Valves).
622+,multiple valve type fluid distributors for plural chamber servo motors. (Plural Valves).
624.11+,for timer controlled flow. (Manual Control, Resetting And Adjusting Devices - Flow Control or Valve Actuation).
624.22,for time cam-operated trips. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
625+,multiway valve units. (Plural Valves).
624.14,for self-cycling flows. (Automatic Control - Line Condition Change Response).
624.27,for line condition change responsive release of valve. (Automatic Control - Line Condition Change Response).
625.61+,for variable orifice modulator for pilot valve of supply and exhaust valve. (Automatic Control - Plural Controls, One Condition Responsive).
624.13+,for repeating cyclic control. (Automatic Control - Periodic or Cyclic).

SECTION IV - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   subclass 11 for heat motor actuators for valves. (Automatic Control - Temperature).
251Valves and Valve Actuation,   subclasses 16+ for main line cut-off after flow period reset by operation of serial main valve. (Automatic Control - Safety cut-offs).
251Valves and Valve Actuation,   subclasses 12+ , for fluid actuated or retarded valves, especially subclasses 15+ for compulsory cut-off after flow period, and subclass 50 for line pressure connected chambers for retarding or timing valves. (Automatic Control - Line Condition Change Response).
251Valves and Valve Actuation,   subclass 11 for buoyancy motor actuators for valves. (Automatic Control - Level Response or Maintenance, Floats, Gravitating Tanks, By floats).
251Valves and Valve Actuation,   subclass 27 for servo failure responsive control of a fluid servo operated valve and 69, for electrical trip actuated valves with trip operation on failure of electric power. (Automatic Control - Failure Responsive and Testing Devices).
251Valves and Valve Actuation,   subclasses 16+ for serial main line cut-off and manual valves, the cut-off operating after a predetermined flow and being reset only by closing the serial manual or mechanically operated valve; subclass 117 for valve and restrictors in parallel flow passages; subclasses 118+ for valves and serial restrictors; subclasses 129+ for valve actuators comprising plural solenoids, which may operate separate valves; and 281+ for balanced valves. (Plural Valves).
251Valves and Valve Actuation,   subclass 3 , for pattern tracer controlled actuators; subclass 11, for heat or buoyancy motor actuators; subclass 12+,for fluid actuators or retarder.; subclass 64,for nonfluid retarder.; subclass 65,for permanent magnet actuators.; subclass 66,for biased trip actuators; subclass 75,for snap action actuators.; subclass 76,for impact type actuators; subclass 77+, for actuators with lost motion.; subclass 89,for means for holding an actuator in set position; subclass 128and 335, for seals for actuator connecting means; subclass 128and 291+, for detachable actuators; subclass 129+,for electrical actuators; subclass 149+and 149.8, for valves operated by conduit motion; subclass 213+,for mechanical movement actuators; subclass 289,for actuation from plural position.; subclass 290,for plural neutral positions of an actuator; subclass 293,for actuator extensions; subclass 294,for flexible actuators; subclass 295,for pedal actuators; subclass 339, for actuators extending through fluid flow path; subclass 340,for actuators surrounding flow pipes; subclass 341 and 349, for valve actuators wherein part of the valve body is movable. (Manual Control, Resetting And Adjusting Devices - Flow Control or Valve Actuation).
251Valves and Valve Actuation,   subclasses 15+ , for fluid actuated valves with compulsory cut-off after a flow period; 48+, for fluid retarders or timers for valves; subclasses 64+, for nonfluid retarders for valves; 66+, for biased trip valve actuation. (Manual Control, Resetting And Adjusting Devices - Cut-Offs with Resetting).
251Valves and Valve Actuation,   subclass 35 for a valve actuated or retarded by a fluid type servomotor having a choke passage that varies according valve position, subclass 42 for a fluid actuated or retarded valve having choke passage pressure type servomotor including an adjustable opening limit for a main valve, subclass 60 for a fluid actuated or retarded valve having an adjustable limit stop, subclasses 84-88 for valve heads movable connected for accommodation to seat, subclasses 120-122 for a valve having a movable or resilient material guide or restrictor, subclass 233 for a valve having a variable leverage lever actuator that is adjustable during operation or subclass 234 for a valve having an adjustable leverage lever.
417Pumps,   for pumps, per se. For distinction of the line between Classes 137 and 417, see the class definition. (Automatic Control - Pump).

SECTION V - GLOSSARY

SPECIAL TYPE CATEGORIES

Those comprising a group of related patents directed toward solving a problem in one specific field of activity, which have been classified on the basis of and under a title reflecting that activity rather than on a generalized basis. Examples of special type categories are 94, Fuel controlled by boiler or water system condition; 108, Pump unloader type (indented under Self-proportioning or correlating systems).

SYSTEM

A term applied to any apparatus of the class which comprises more than a single flow path and/or a single valve unit. It may include only an unvalved branched flow path or a single flow path having two or more valve units. In some instances subcombinations or elements having special utility in the combination and having no other classification have been included in the group of subclasses pertaining to the system, as subclasses 777-802, Expansible Chamber Devices.

VALVES AND VALVE ACTUATION

The term "valve unit," as used above, is applied to either a single or multiway valve. In the multiway type plural passages are controlled by valve means having plural flow closing areas or points, but the entire means is housed in a single casing or organized as a body or unit. Valve units as such are classified in subclasses 625+. The class also provides for some valve units under the special titles. Radiator vent check valves, Reversing cokes and valves, Flush or water closet valves, Drain valves, Float valves, Temperature operated cut-off valves, Safety valves, and certain analogous types. The class also takes valves combined with other structure, as the tire inflation type combined with or adapted for connection with inflation means and/or the inflatable article. Class 251, Valves and Valve Actuation provides for valves combined with certain actuators, particularly the fluid and electric motors and the more complex mechanical movement actuators.

The term "Valves" includes variable restrictors, which frequently cannot be distinguished as claimed, and have been set apart only in certain subclasses having the term restrictor or choke in the title, as subclasses 436+, and 475+, primarily because of their special function as silencers. Closures are also frequently indistinguishable from valves, particularly as used and claimed in fluid handling systems. In some instances they have been classified with valves, as in subclasses 613+, Single flow path with plural serial valves and/or closures and Class 251, Valves and Valve Actuation, provides for restrictors or flow guides in subclasses 118.01+.

SUBCLASSES

[List of Patents for class 137 subclass 1]    1PROCESSES:
 This subclass is indented under the class definition.  Processes.
(1) Note. All patents containing method claims drawn to the method of operation of any of the systems or parts thereof involved in the class are included in this and the indented subclasses, but methods of making parts of the system are not included. They will be found in the subclass providing for the system or part.
(2) Note. This subclass includes, for example, methods of operation of speed regulators for prime movers, valves, fluid motors; methods of developing fluid pressures by series parallel combinations of pumps, tanks or pipes; methods for affecting fluid flow by using pipe sections of varying diameter or joined at critical angles, or by slugging.

SEE OR SEARCH CLASS:

166Wells,   subclasses 244.1+ for process of flowing or treating a well; and particularly subclasses 373+ for a method of operating a valve, closure, or changeable restrictor in a well wherein some significant manipulative step regarding the well is recited.
210Liquid Purification or Separation,   subclasses 606 , 631, 632, 639, 663+, 696+, 702+, and 749+ for a process comprising the step of adding a chemical to a liquid with treatment of the liquid.
222Dispensing,   subclass 1 for processes of dispensing.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotographic device.
414Material or Article Handling,   subclasses 800+ for a process of material or article handling.
  
[List of Patents for class 137 subclass 2]    2With control of flow by a condition or characteristic of a fluid:
 This subclass is indented under subclass 1.  Processes in which one or more conditions or characteristics of a fluent material are determined and used to control the system in such a manner as to cause delivery of controlled quantities of a fluent material at a part of the system.
(1) Note. See the main class definition, for collected search notes on automatic fluid handling devices of this and related classes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

455+,for line condition change responsive valves, and see the search notes to subclass 455.
  
[List of Patents for class 137 subclass 3]    3Mixing of plural fluids of diverse characteristics or conditions:
 This subclass is indented under subclass 2.  Processes in which two or more fluent materials of different conditions or characteristics are mixed and the determined condition or characteristic may be taken from any or all the fluent materials and used to control the quantitative flow in any or all the branches or in the mixed channel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

87.01+,for self proportioning or correlating systems, especially subclasses 88+ for those involving mixture condition maintaining or sensing.
  
[List of Patents for class 137 subclass 4]    4Controlled by consistency of mixture:
 This subclass is indented under subclass 3.  Processes in which the determined condition is the consistency of the mixture.

SEE OR SEARCH THIS CLASS, SUBCLASS:

92,for systems for mixture condition maintaining or sensing by viscosity or consistency.
467.5,for line consistency responsive flow controller.
  
[List of Patents for class 137 subclass 5]    5Controlled by conductivity of mixture:
 This subclass is indented under subclass 3.  Processes in which the determined condition is the conductivity of the mixture.

SEE OR SEARCH THIS CLASS, SUBCLASS:

93,for systems for maintaining or sensing a mixture condition by optical or chemical properties.
  
[List of Patents for class 137 subclass 6]    6Controlled by heat of combustion of mixture:
 This subclass is indented under subclass 3.  Processes in which the determined condition or characteristic is the heat of combustion of the mixture.

SEE OR SEARCH THIS CLASS, SUBCLASS:

90,for systems of mixture condition maintaining or sensing by temperature or heat content.

SEE OR SEARCH CLASS:

431Combustion,   subclass 12 for a process of combustion involving the control or proportioning of burner feed.
  
[List of Patents for class 137 subclass 7]    7Controlled by pressure:
 This subclass is indented under subclass 3.  Processes in which the determined condition or characteristic is a pressure.

SEE OR SEARCH THIS CLASS, SUBCLASS:

87.01+,for self-correlating or proportioning flow systems controlled by the pressure in one or more flow lines or branches.
  
[List of Patents for class 137 subclass 8]    8For producing uniform flow:
 This subclass is indented under subclass 2.  Processes in which one or more characteristics or conditions of a fluent material is determined and used to control the system in such a manner as to cause a uniform flow of a fluent material through a part of the system.

SEE OR SEARCH THIS CLASS, SUBCLASS:

494+,particularly subclasses 505+ for pressure regulators having a separate connected reactor service.
517+,for direct response condition change controlled valves of the pressure regulating type, and see the search notes to subclass 517.

SEE OR SEARCH CLASS:

222Dispensing,   subclass 55 for dispensers which maintain a constant weight, volume or pressure by means controlled by the output.
  
[List of Patents for class 137 subclass 9]    9For producing proportionate flow:
 This subclass is indented under subclass 2.  Processes in which one or more conditions of a fluent material is determined and used to produce or control the flow of a fluent material at a part of the system, which flow is regulated by the condition or conditions sensed so as to vary proportionally therewith.
(1) Note. The flow in which the condition is sensed may be the controlled flow or a different flow.

SEE OR SEARCH THIS CLASS, SUBCLASS:

82+,for pressure modulating relays or followers, per se.
98+,for self-proportioning flow systems.
109+,for self-controlled branched flow systems.
  
[List of Patents for class 137 subclass 10]    10By speed of fluid:
 This subclass is indented under subclass 2.  Processes in which the condition or characteristic determined is the speed of the fluent material of the system.

SEE OR SEARCH THIS CLASS, SUBCLASS:

497+,for line condition responsive valves which are responsive to a change in the rate of fluid flow, and see the search notes to subclass 497.
  
[List of Patents for class 137 subclass 11]    11For regulating boiler feed water level:
 This subclass is indented under subclass 2.  Processes in which one or more conditions or characteristics of a fluent material is determined and used to control the flow of boiler feed water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

94,for fuel control devices for boilers responsive to boiler or water system conditions.
156+,for gas pressure discharge of liquid feed traps to boilers.
386+,for liquid level responsive or maintaining systems.

SEE OR SEARCH CLASS:

122Liquid Heaters and Vaporizers,   subclasses 451+ for boiler feeders combined with boilers, and subclasses 412+ for boiler feed heaters.
  
[List of Patents for class 137 subclass 12]    12By fluid pressure:
 This subclass is indented under subclass 2.  Processes in which the condition or characteristic which is determined is a fluid pressure and the determination is used to cause delivery of controlled quantity of a fluent material at a part of the system.

SEE OR SEARCH THIS CLASS, SUBCLASS:

7,for processes of mixture control depending on pressure sensing.
455+,for line condition change responsive valves, and see the search notes to subclass 455.
  
[List of Patents for class 137 subclass 12.5]    12.5Carbonated beverage handling processes:
 This subclass is indented under subclass 1.  Processes for handling potable liquids which are impregnated with gas.

SEE OR SEARCH THIS CLASS, SUBCLASS:

154+,for systems which contain, under pressure, a plurality of diverse type fluids, as gas and liquids, and especially 170.1+ for apparatus for controlling foam in handling such liquids, and 206+ for gas pressure storage over or displacement of liquids in such systems.

SEE OR SEARCH CLASS:

222Dispensing,   subclass 1 for dispensing methods and subclasses 394 and 396 to 402 for apparatus for dispensing liquids under fluid (gas) pressure.
426Food or Edible Material: Processes, Compositions, and Products,   appropriate subclasses, especially 474+ for process involving gas-liquid contact including preparation of carbonated beverages.
  
[List of Patents for class 137 subclass 13]    13Affecting flow by the addition of material or energy:
 This subclass is indented under subclass 1.  Processes in which the flow of fluent material is facilitated by the addition of material which affects the flow characteristics of the fluent material, or by the application of heat or other forms of energy.

SEE OR SEARCH THIS CLASS, SUBCLASS:

3,for processes of mixing plural fluids with automatic control.
88+,for automatic mixture condition maintaining by the addition of materials, etc.
334+,for fluid handling means combined with heating means, and see the search notes thereto.
565.01+,for distribution systems comprising pumps, and see the search notes thereto.
803+,for a pure fluid device or system capable of performing the process of this subclass (13).

SEE OR SEARCH CLASS:

208Mineral Oils: Processes and Products,   subclass 370 for miscellaneous treatments of mineral oils during transportation.
507Earth Boring, Well Treating, and Oil Field Chemistry,   subclass 90 for compositions for preventing contaminant deposits in petroleum oil conduits and methods of preventing such deposits involving no significant manipulative steps.
516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   appropriate subclasses for subject matter relating to: colloid systems (such as sols*, emulsions, dispersions, foams, aerosols, smokes, gels, or pastes) or wetting agents (such as leveling, penetrating, or spreading); subcombination compositions of colloid systems containing at least an agent specialized and designed for or peculiar to use in making or stabilizing colloid systems; compositions and subcombination compositions specialized and designed for or peculiar to use in breaking (resolving) or inhibiting colloid systems; processes of making the compositions or systems of the class; processes of breaking (resolving) or inhibiting colloid systems; in each instance, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
520Synthetic Resins or Natural Rubbers,   appropriate subclasses, particularly Class 523, subclass 175 for a composition containing a synthetic resin or natural rubber having utility related to improving drag reduction formation or systems which are effective for reducing the dynamic drag of a turbulent fluid in contact with a surface or to processes of preparing said composition.
  
[List of Patents for class 137 subclass 14]    14Involving pressure control:
 This subclass is indented under subclass 1.  Processes in which the pressure of the fluent material is reduced for the purpose of facilitating handling of the material or avoiding damage to the equipment, or equalized with the pressure in another part of the system or a container to facilitate transfer of the fluent material or of control thereof, or regulated to maintain the pressure of the fluent material at a desired value.

SEE OR SEARCH THIS CLASS, SUBCLASS:

7,for processes of mixing fluids automatically controlled by pressure.
12,for processes for controlling the flow of material by sensing the pressure thereof.
  
[List of Patents for class 137 subclass 15.01]    15.01Cleaning, repairing, or assembling:
 This subclass is indented under subclass 1.  Subject matter wherein the method comprises the removal of undesirable material from the system, restoration of the system or its component to a sound condition, or connecting together various components of the system.

Image 1 for class 137 subclass 15.01

Image 2 for class 137 subclass 15.01

Image 3 for class 137 subclass 15.01

Figures 1, 2, and 3: A typical example of the subject mattershowing various steps of assembling and mounting a faucet structure.A - Sink deck; B - Valve stem; C - Nut; D - Protective shield; E- Groove; F - "C" clip; G - Spout tube; H - Spout bolt; J - Clampingscrew; K - Wrench; L - Draw spout.

SEE OR SEARCH THIS CLASS, SUBCLASS:

237through 246.23, with cleaner, lubrication added to fluid or liquid sealing at a valve interface.
315.01through 329.4, for a fluid handling system with repair, tapping or assembly means.

SEE OR SEARCH CLASS:

29Metal Working,   subclasses 402.01 through 402.21for a method of mechanical repair.
166Wells,   subclass 277 for a process of repairing an object in a well, subclasses 311-312 for a process of cleaning or unloading a well or subclasses 378-380 for a process of assembling a well part.
  
[List of Patents for class 137 subclass 15.02]    15.02Repairing or assembling hydrant (e.g., fireplug, etc.):
 This subclass is indented under subclass 15.01.  Subject matter wherein the process of repairing or assembling is directed to a system having a discharge pipe including a valve and a spout, at which water may be drawn from a water main or water system.

Image 1 for class 137 subclass 15.02

Figure 1: A typical example of the subject matter. A - Firehydrant; B - Nozzle; C - Cap; D - Jet of water; E - Nozzle expanderbolted to "B" by bolts "F"; F - Bolts; G - Shutoff valve; H - Flange;J - Bolts secure to "E" and "G".

SEE OR SEARCH THIS CLASS, SUBCLASS:

236.1,for a fluid handling distribution system involving a geographic feature.
272through 308, for a hydrant type.
  
[List of Patents for class 137 subclass 15.03]    15.03Gas or water meter repairing or assembling:
 This subclass is indented under subclass 15.01.  Subject matter wherein the process of repairing or assembling is directed to an instrument for measuring and recording the quantity of combustible mixture used for commercial or industrial heating or for measuring and recording the quantity of water supplied for commercial or domestic use.

Image 1 for class 137 subclass 15.03

A typical example of the subject matter. Figure 1: A - Gasmeter; B - Outlet gas supply; C - Control valve; D - Regulator;E - Riser nipple; F - Relief valve.

Image 2 for class 137 subclass 15.03

Figure 2: A - Water meter; B - Backflow prevention valve;C - Meter pit; D - Coaxial fitting; E - Fluid conduit; F - Flowcontrol valve; G - Fittings to facilitate meter mounting.

SEE OR SEARCH THIS CLASS, SUBCLASS:

364through 371, for a static ground supported valve or meter well.

SEE OR SEARCH CLASS:

138Pipes and Tubular Conduits,   subclasses 97 through 99for repairing of a pipe or tubular conduit.
  
[List of Patents for class 137 subclass 15.04]    15.04Fluid cleaning or flushing:
 This subclass is indented under subclass 15.01.  Subject matter wherein the process of comprises injecting a pressurized gas, liquid, or a mixture of flowable solid and liquid through the system to eliminate or wash out the material from the system.
(1) Note. The liquid may contain a solid particle.

Image 1 for class 137 subclass 15.04

Figure 1: A typical example of the subject matter. A -Storage tank; B - Oil; C - Sludge (unwanted material); D - Tankroof; E - Loading valve; F - Riser; G - Pump hose (pressuirzed cleaningfluid); H - Bottom hose; J - Main valve.

SEE OR SEARCH THIS CLASS, SUBCLASS:

238through 245.5, for a fluid handling system with a cleaning or steam sterilizing means.

SEE OR SEARCH CLASS:

15Brushing, Scrubbing, and General Cleaning,   subclass 246.5 for a brushing, scrubbing, or general cleaning implement, device, or machine attached to a tank.
  
[List of Patents for class 137 subclass 15.05]    15.05Liquid cleaning or flushing:
 This subclass is indented under subclass 15.04.  Subject matter wherein the process of washing out or eliminating the undesirable material from the system is accomplished by use of a desirable material which is a fluid that is not in gaseous form.

Image 1 for class 137 subclass 15.05

Figure 1: A typical example of the subject matter. Brake cylinder"A" is filled with brake liquid "B". Inlet valve "C" is providedfor introduction of new brake liquid. The outlet valve "D" is forremoval of spent brake liquid due to purging.

SEE OR SEARCH CLASS:

134Cleaning and Liquid Contact with Solids,   subclass 22.12 for a process of cleaning the internal surface of a pipe, tubing, hose, or conduit with pressurized fluid or fluid manipulation, or subclass 40 for a process of removing oil, grease, tar, or wax by dissolving.
  
[List of Patents for class 137 subclass 15.06]    15.06Valve or valve seat cleaning:
 This subclass is indented under subclass 15.05.  Subject matter wherein the flushing liquid is being passed through the body of a flow regulating device or around the circular ring or annular sealing surface used for resting or supporting the head of the device.

Image 1 for class 137 subclass 15.06

Figure 1: A typical example of the subject matter. A - Seatassembly; B - Valve seat; C - Replaceable gasket; D - Representswashing fluid being flushed; E, F - Path of washing fluid throughslots of gasket.

SEE OR SEARCH THIS CLASS, SUBCLASS:

246through 246.23, for a fluid handling system with liquid supplied at a valve interface for sealing.
  
[List of Patents for class 137 subclass 15.07]    15.07Mechanical cleaning (e.g., pig, etc.):
 This subclass is indented under subclass 15.01.  Subject matter comprising an internally movable element consisting of a brush, scraper, inflatable ring, or similar means used for removing undesirable material from the system.
(1) Note. The pig is an in-line scraper, brush, blade, cutter, or swab forced through a pipeline by fluid pressure to remove undesirable material.

Image 1 for class 137 subclass 15.07

Figure 1: A typical example of the subject matter. A -Cleaning tool to clean "B" of "B1"; B - Axial bore; B1 - Manifoldbody; C - Manifold flange; D - Manifold opening for "E"; E - Mountingbolt; F, G, H, J, K, L - Cleaning tool assembly; M - Cleaning memberwith sharp edge.

SEE OR SEARCH CLASS:

15Brushing, Scrubbing, or General Cleaning,   subclasses 3.5 through 3.52for a machine with means to pass a solid cleaning agent and a fluid carrier through tubular work or subclasses 104.03-104.33 for a pipe, tube, or conduit cleaning implement, especially subclasses 104.05-104.33 for an implement to clean inside a pipe, tube, or conduit.
138Pipes and Tubular Products,   subclass 93 for a pipe or conduit with an inflatable closure or plug.
  
[List of Patents for class 137 subclass 15.08]    15.08Repairing, securing, replacing, or servicing pipe, joint, valve, or tank:
 This subclass is indented under subclass 15.01.  Subject matter wherein the process is directed to a tubular product, coupling, a flow regulating device, or a container or receptacle.

Image 1 for class 137 subclass 15.08

Figures 1and 2: A typical example of the subject matter. A- Supply main; B - Pipe saddle; C - Pipe conduit; D - Coupling;E - Flange adaptor; F - Coupled assembly; G - Standard tool; H -Control valve.

SEE OR SEARCH CLASS:

138Pipes and Tubular Conduits,   subclasses 97 through 99for repairing of a pipe or tubular conduit.
251Valves and Valve Actuation,   subclass 152 for a correlated flow line having a pipe coupling or union where a valve seat and coupling element is removable as a unit.
285Pipe Joints or Couplings,   subclasses 18 through 40for a pipe joint or coupling with assembly means or feature.
  
[List of Patents for class 137 subclass 15.09]    15.09Including joint or coupling:
 This subclass is indented under subclass 15.08.  Subject matter wherein the significance is attributed to a union formed by two abutting pipes or ducts, an area at which two ends or edges of the pipe or duct are attached, or a device that serves to connect the ends of adjacent parts of a pipe or duct.

Image 1 for class 137 subclass 15.09

A typical example of the subject matter. Figure 1: COUPLING:A, B - Flanges; C - Gasket; D - Band; E, F - Welds; G - Seat; H,J - Sealing nuts; K - Bolt.

Image 2 for class 137 subclass 15.09

Figure 2: PIPE JOINT: A - Pipe Joint; B, C - Pipe; D - Internalshelf; E - Connector; F - Fitting.

SEE OR SEARCH CLASS:

29Metal Working,   subclasses 509 through 513for a method of assembling by deforming a part over an edge of a seated part or subclasses 525.01-525.15 for assembling or joining by applying separate fastener.
285Pipe Joints or Couplings,   subclasses 15 through 17having repairing means, subclasses 18-40 with or having means to assemble or disassemble, or subclasses 363-368 for a flanged pipe joint having a packing.
403Joints and Connections,   subclasses 11 through 22for a protector or broken part retainer with repair, assembly, or disassembly feature.
405Hydraulics and Earth Engineering,   subclasses 169 through 170for assembling a line of pipe or cable in or from a marine environment.
  
[List of Patents for class 137 subclass 15.1]    15.1HIGHSPEED FLUID INTAKE MEANS (E.G., JET ENGINE INTAKE):
 This subclass is indented under the class definition.  Apparatus comprising intake means described for use in an ambient gaseous medium to gather a portion of that medium, said incoming medium moving at a relatively high speed with respect to the intake means, said intake means comprising a flow passage for the incoming medium, said flow passage disclosed as having at least (1), a portion which converges in the direction of flow or (2), a portion which diverges in the direction of flow or (3), an enlarged portion downstream of the intake end.
(1) Note. Many of the patents herein disclose the intake means as being used to convert a portion of the kinetic energy of the incoming gas into static pressure energy.
(2) Note. A claim to merely recite the wall structure of a tubular member, or to a mere tubular member with a restricting or baffle means for facilitating or restricting flow of fluid is classifiable in Class 138, Pipes and Tubular Conduits. For classification in Class 137, some additional fluid handling features must be claimed. See the reference to Class 137 under "SEARCH CLASS" in the definition of subclass 37 in Class 138.
(3) Note. A claim with a nominal recitation of the apparatus to which the incoming gaseous medium is being delivered, (e.g., jet engine, pump), in combination with the intake means, does not preclude classification in Class 137.
  
[List of Patents for class 137 subclass 15.11]    15.11Detecting or repairing leak:
 This subclass is indented under subclass 15.08.  Subject matter wherein the significance is attributed to discovering or determining presence or existence of a crack, crevice, or hole that usually by wear and tear or mishap allows gas or liquid to escape, and restoring to a sound condition by patching, applying, or injecting a liquid, semi-liquid, or semi-solid material to prevent gas or liquid entry to or loss from a pipe, duct, container, or valving system.

Image 1 for class 137 subclass 15.11

A typical example of the subject matter. Figure 1: INJECTINGSEALANT: A - Leak repair clamp; B - Pipe line; C - Cavity for receivingsealant; D - Passageway for sealant injection; E - Stopper plug.

Image 2 for class 137 subclass 15.11

Figure 2: FLEXIBLE PATCH: A - Sealing leak; B - Pipe; C- Sealing patch.

SEE OR SEARCH THIS CLASS, SUBCLASS:

312through 314, for leakage or drip collecting.

SEE OR SEARCH CLASS:

29Metal Working,   subclasses 402.09 through 402.17for a method of repairing by attaching a repair preform (e.g., remaking, restoring, patching, etc.).
73Measuring and Testing,   subclasses 40 through 49.3using fluid pressure to test or determine a leak.
228Metal Fusion Bonding,   subclass 119 for a process of repairing, restoring, or renewing a product for reuse.
285Pipe Joints and Couplings,   subclasses 13 through 14for leakage or drip disposal including weep holes.
  
[List of Patents for class 137 subclass 15.12]    15.12Tapping pipe, keg, or tank:
 This subclass is indented under subclass 15.08.  Subject matter wherein the significance is attributed to piercing an aperture or removing a plug from a tubular product, a small cask or barrel, or a container or receptacle used for transporting, holding, or storing a gas or liquid.

Image 1 for class 137 subclass 15.12

Figure 1: A typical example of the subject matter. A - Concretetube or pipe; B - Tensioned wires; C - Cement coating; D - Sealinggland; E - Shell cutter; F - Film (auxiliary coating); G - Saddle;H - Straps; J - Saddle neck; K - Gasket; L - Tightening bolts; M- Grout; N - Valve casing; P - Valve; Q - Adapter for tapping machine;R - Tapping machine; S - Conduit for fluid under pressure; T - Cuttingmachine shaft; V - Centering drill.

SEE OR SEARCH THIS CLASS, SUBCLASS:

317through 325, for an apparatus for tapping a pipe, keg or apertured tank under pressure.

SEE OR SEARCH CLASS:

29Metal Working,   subclasses 522.1 through 524.1for a method of assembly or joining by deforming a radially expanding part in a cavity, aperture, or hollow body or subclasses 890.14-890.15 for a method of making a specific gas or water plumbing component.
138Pipes and Tubular Products,   subclasses 94 through 94.5for a laterally insertable closure or plug.
  
[List of Patents for class 137 subclass 15.13]    15.13Particular aperture forming means:
 This subclass is indented under subclass 15.12.  Subject matter wherein the significance is attributed to creating a hole, gap, indentation, or a narrow, deep opening.

Image 1 for class 137 subclass 15.13

Figure 1: A typical example of the subject matter. A - Nipple(outer end); B - Exterior threads; C - Enlarged outer end portion;D - Perforating tool; E - Exterior taper; F Main pipe; G - Allenwrench; H - Passageway; J - Valve.

SEE OR SEARCH THIS CLASS, SUBCLASS:

318,for an apparatus for tapping a pipe, keg, or apertured tank under pressure with aperture forming means.

SEE OR SEARCH CLASS:

83Cutting,   subclass 54 for a process of cutting the wall of a hollow work in general.
408Cutting by Use of Rotating Axially Moving Tool,   subclasses 22 through 30combined with diverse cutting means, subclass 704 for drilling small holes, or subclass 705 for drilling deep holes.
  
[List of Patents for class 137 subclass 15.14]    15.14Cutter or cutting tool:
 This subclass is indented under subclass 15.13.  Subject matter comprising a shearing device to remove a portion of the pipe or keg to provide an aperture.

Image 1 for class 137 subclass 15.14

Figure 1: A typical example of the subject matter. A - Cutterassembly; B - Piston; C - Recess; D - Bushing; E - Resilient ring;F - Cutter; G - Tubular insert; H - Annular ring; J - Pipe wall;K - Cut portion (coupon); L - Allen wrench; M - Piston movement.

SEE OR SEARCH CLASS:

83Cutting,   subclass 30 for a process of puncturing or subclass 54 for a process of cutting a wall of hollow work.
222Dispensing,   subclasses 81 through 90for a cutter or punch to form a dispensing opening in a container.
228Metal Fusion Bonding,   subclass 171 for a process of producing opposed complementary matching bonding surfaces by cutting prior to bonding.
408Cutting by Use of Rotating Axially Moving Tool,   subclasses 87 through 102for a cutting tool in combination with a tool-opposing, work-engaging surface.
  
[List of Patents for class 137 subclass 15.15]    15.15Having deformable or inflatable means:
 This subclass is indented under subclass 15.13.  Subject matter wherein the method of forming an aperture further includes sealing by use of an abnormally expandable bladder, compressible stopper, or similar resilient member.

Image 1 for class 137 subclass 15.15

Figure 1: A typical example of the subject matter. A - Pipemain; B - Resilient plug (inflatable); C - Inner rod; D - Saddle;E - Opening in pipe; F - Pipe plug; G - Stopper rod; H - Intermediaterod; J - U-bolt; K - Service tree.

SEE OR SEARCH CLASS:

138Pipes and Tubular Conduits,   subclasses 89.1 through 89.2for an inflation stem type air and dust cap, subclass 89.3 for an inflation stem type air cap, subclass 89.4 for an inflation stem type dust cap, subclass 93 for an inflatable closure or plug, subclasses 94-94.5 for a laterally insertable closure or plug, or subclasses 97-99 for repairing a pipe or tubular conduit.
  
[List of Patents for class 137 subclass 15.16]    15.16With content loading or unloading (e.g., dispensing, discharge assistant, etc.):
 This subclass is indented under subclass 15.08.  Subject matter comprising a method of filling the pipeline or tank with a substance or material or removing a substance or material from a pipeline or tank.

Image 1 for class 137 subclass 15.16

Figure 1: A typical example of the subject matter. A - Vessel;B - Viscous material; C - Gear pump; D - Drain opening; E - Boss;F - Valve body; G - Flange connection; H - Side outlet; J - Piston;K - Actuator; L - Hose; M - Container; N - Solenoid valve.

SEE OR SEARCH THIS CLASS, SUBCLASS:

587through 588, for a fluid handling system having a tank that includes a gas vent and a liquid inlet or outlet.

SEE OR SEARCH CLASS:

141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclasses 2 through 3for a process of filling a dispenser or subclasses 5-7 for a process of manipulating gas within the receiver and filling with fluent nongaseous materials, especially subclass 7 for a process of evacuation of a container.
222Dispensing,   subclasses 321.1 through 321.9with discharge assistant (e.g., impeller, pump, conveyer, movable trap chamber, etc.), a movable nozzle interconnected with it and a material supply container and discharge assistant casing.
  
[List of Patents for class 137 subclass 15.17]    15.17Specific valve or valve element mounting or repairing:
 This subclass is indented under subclass 15.08.  Subject matter wherein the significance is attributed to the process of installing, replacing, or servicing a flow regulating device or its component.

Image 1 for class 137 subclass 15.17

Figure 1: A typical example of the subject matter. A - Valveassembly; B - Interior wall; C - Distribution pipe; D - Tank; E- Tank inlet; F - Main valve; G - Water inlet line; H - Flexibletube; J - Fittings.

SEE OR SEARCH THIS CLASS, SUBCLASS:

15.18through 15.26, for a process of assembling, disassembling, or repairing a valve or valve member.

SEE OR SEARCH CLASS:

29Metal Working,   subclasses 213.1 through 221.6for assembly or disassembly means for applying or removing a valve, subclass 890.121 for a method of repairing, converting, servicing, or salvaging a valve or choke, or subclasses 890.124-890.131 for a method of assembly, disassembly, or composite valve or choke making.
  
[List of Patents for class 137 subclass 15.18]    15.18Valve or valve element assembling, disassembling, or repairing:
 This subclass is indented under subclass 15.01.  Subject matter wherein the significance is attributed to the process of installing, replacing, or securing a flow regulating device or its component.

Image 1 for class 137 subclass 15.18

Figure 1: A typical example of the subject matter. A - Valvebody; B - Inlet port; C - Outlet port; D - Flanges; E - Valve chamber;F - Seat sections; G - Valve body portion; H - Hanger surface; J- Hanger recess; K - Clapper; L - Annular ring; M- Spherical segment;N - Annular recess; P - Clapper pin; Q - Bushing.

SEE OR SEARCH THIS CLASS, SUBCLASS:

15.17,for a process having a particular repairing or mounting feature for the valve or valve member.
329.01through 329.06, for repair by means where a valve head or seat is replaceable or having an unworn surface movable into operative position.

SEE OR SEARCH CLASS:

29Metal Working,   subclasses 213.1 through 221.6for assembly or disassembly means for applying or removing a valve, subclass 890.121 for a method of repairing, converting, servicing, or salvaging a valve or choke, or subclasses 890.124-890.131 for a method of assembly, disassembly, or composite valve or choke making.
  
[List of Patents for class 137 subclass 15.19]    15.19Fluid actuated or retarded:
 This subclass is indented under subclass 15.18.  Subject matter wherein the significance is attributed to the opening or closing movement of the valve and is produced by the relative force of a gas, liquid, or a mixture of a solid and liquid.

Image 1 for class 137 subclass 15.19

Figure 1: A typical example of the subject matter. A - Controlvalve; B - Valve stem; C, D, E, F - Lever and link mechanism; G- Piston; H - Servomechanism; J - Actuator; K - Manifold to controlactuator.

SEE OR SEARCH THIS CLASS, SUBCLASS:

601.13,for systems dividing into parallel flow lines then recombining having a fluid actuated or retarded valve.

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   subclasses 12 through 63.6for a fluid actuated or retarded valve actuating means or subclass 175 for means to increase head and seat contact by fluid pressure.
  
[List of Patents for class 137 subclass 15.2]    15.2With condition responsive control means:
 This subclass is indented under subclass 15.1.  Apparatus having means sensing a condition of the ambient medium, or of the medium flowing through the intake means, said sensing means controlling operation of a control means for the medium flowing through the intake means, or for a separate fluid.

SEE OR SEARCH THIS CLASS, SUBCLASS:

601.13,for systems dividing into parallel flow lines then recombining having a fluid actuated or retarded valve.

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   subclasses 12 through 63.6for a fluid actuated or retarded valve actuating means or subclass 175 for means to increase head and seat contact by fluid pressure.
  
[List of Patents for class 137 subclass 15.21]    15.21Multi way valve:
 This subclass is indented under subclass 15.18.  Subject matter wherein the valve regulates or controls a plurality of flow lines.

Image 1 for class 137 subclass 15.21

Figure 1: A typical example of the subject matter. A - Valvebody; B - Valve cage; C - Valve plug; D - Valve stem; E - Bonnet;F, G - Valve ports; H - Central boss; J - Valve body bridge; K,L - Side ports; M - Bottom port.

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315.09,for a fluid handling system with means for assembling or disassembling a multi way valve device.
625through 625.5, for a multi way valve unit.
  
[List of Patents for class 137 subclass 15.22]    15.22Ball valve or rotary ball valve:
 This subclass is indented under subclass 15.18.  Subject matter wherein the significance is attributed to a valve comprising a recriprocating spherical element, a pivoting spherical element, or a housing having a flow passage therethrough with a valve seat, and a spherical head that contacts the seat and can be rotated about an axis passing generally through its geometrical center by actuating means.

Image 1 for class 137 subclass 15.22

Figure 1: A typical example of the subject matter. A - Valveseat; B - Upper valve seat; C - Lower valve seat; D - Packings;E, F - Retainers; G, H -Bearing packings; J - Valve box; K - Valverod; L - Packing gland; M - Gland screw; N - Ball handle; P - Capnut; Q - Lock nut; R, S, T - Fluid passages.

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315.18through 315.21, for a rotary ball valve with assembling or disassembling.

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251Valves and Valve Actuation,   subclasses 315.1 through 315.15for housing construction for a ball valve.
  
[List of Patents for class 137 subclass 15.23]    15.23Gate valve:
 This subclass is indented under subclass 15.18.  Subject matter wherein the significance is attributed to a valve comprising essentially a wedge-shaped or flat sliding plate that can be lowered into a seat or raised to regulate fluid flow.

Image 1 for class 137 subclass 15.23

Figure 1: A typical example of the subject matter. A - Gatevalve; B - Valve body; C - Passageway; D -Valve gate; E - Valveseats; F - Valve stem; G - Valve yoke; H - Valve handle.

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315.29through 315.32, for a reciprocating gate valve with assembling or disassembling means.
625.45,for system shaving a multi way valve unit that uses a pivoted gate valve unit.
625.49,for systems having a multi way valve unit that uses a reciprocating combined disk or plug for closing one port and a gate or piston valve for closing another port.

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251Valves and Valve Actuation,   subclass 300 for a pivoted terminal gate valve, subclasses 301-302 for a pivoted gate valve, or subclasses 326-329 for a reciprocating gate valve.
  
[List of Patents for class 137 subclass 15.24]    15.24Plug valve:
 This subclass is indented under subclass 15.18.  Subject matter wherein the significance is attributed to a valve comprising a cock with a conical or cylindrical piece which is being turned to regulate the flow.

Image 1 for class 137 subclass 15.24

Figure 1: A typical example of the subject matter. A - Valveassembly; B, C - Inlet and outlet in axial alignment with each other;D - Cylindrical plug assembly with valve assembly "A"; E - Upperactuating portion of plug "D"; F - Lower actuating portion of plug"D"; G, H - Sealing grooves for plug "D"; J - Plug valve handle;K - Valve support surface.

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315.25through 315.26, for a plug valve with means to assemble or disassemble.

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251Valves and Valve Actuation,   subclasses 309 through 312for a rotary plug valve or subclass 904 for a snap-fit plug valve.
  
[List of Patents for class 137 subclass 15.25]    15.25Butterfly valve:
 This subclass is indented under subclass 15.18.  Subject matter wherein significance is attributed to a valve comprising a substantially flat and coplaner wings depending from a central axis of rotation.

Image 1 for class 137 subclass 15.25

Figure 1: A typical example of the subject matter. A - Throttlevalve shaft; B - Cylindrical bosses; C - Throttle valve disk; D- Spring retainer and lever; E - Holes to receive bosses "B".

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315.22through 315.24, for a butterfly valve with assembly or disassembly means.
601.17,for systems dividing into parallel flow lines then recombining including a butterfly valve.

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29Metal Working,   subclasses 890.124 through 890.131for valve making in general with assembly, disassembly, or composite article making.
454Ventilation,   subclasses 333 through 336for an adjustable damper type valve; subclass 369 for a fire damper in general.
  
[List of Patents for class 137 subclass 15.26]    15.26Float valve:
 This subclass is indented under subclass 15.18.  Subject matter wherein the significance is attributed to a valve comprising a hollow, buoyant element, usually attached at the end of a lever, providing positive buoyancy while resting on the fluid surface.

Image 1 for class 137 subclass 15.26

Figure 1: A typical example of the subject matter. A - Tank;B - Water level; C - Standpipe; D - Ballcock valve; E - Lever arm;F - Float; G - Port; H - Fill tube. Note: Valve "D" operates suchthat downward articulation of lever arm "E" causes valve "D" toopen so that water can communicate between port "G" and the fill tube"H".

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165through 168, for a float responsive to liquid in a trap (e.g., boiler, etc.) to control gas pressure within the trap.
315.08,for a fluid handling system combined with means to assemble or disassemble a float or float valve.
409through 451, for a liquid level responsive or maintaining system by a float controlled valve.

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73Measuring and Testing,   subclass 322.5 for a float structure.
119Animal Husbandry,   subclasses 78 through 80for a watering or liquid feed device with a float-controlled supply.
340Communications: Electrical,   subclasses 623 through 625for a liquid level responsive indicating system using a float sensor.
  
[List of Patents for class 137 subclass 38]    38CONTROL BY CHANGE OF POSITION OR INERTIA OF SYSTEM:
 This subclass is indented under the class definition.  Apparatus wherein a flow of fluid is controlled in response to (1) the shifting of the position of the system as a whole relative to gravitational field or to a body of liquid in which the system exists or (2) the inertia or dislocation of the system as a whole.
(1) Note. Systems which are controlled by overflow pipes or arrangements are excluded from this and indented subclasses and are classified on a basis appropriate to the system claimed.

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53+,for systems wherein the control is in response to the inertia or position of a speed responsive element (e.g., fly ball governors).
581,for distribution systems comprising a movable tank.

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184Lubrication,   subclass 26 for lubricating pumps operated by the vibration of a machine.
220Receptacles,   subclasses 203.19+ for a receptacle closure comprising a pressure responsive vent or valve which is also responsive to tilting of the receptacle.
222Dispensing,   subclasses 160+ for movably mounted supply containers for dispensers; subclasses 454+ for dispensers which have a trap which is filled and emptied solely by the tilting motion of the assembly, and subclasses 500+ for dispensers having gravity or inertia operated outlet elements.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
417Pumps,   subclasses 231+ for pumps operated by a vehicle.
700Data Processing: Generic Control Systems or Specific Applications,   subclass 281 for control of fluid level or volume, and subclasses 282-285 for flow control.
  
[List of Patents for class 137 subclass 39]    39With second control:
 This subclass is indented under subclass 38.  Apparatus which includes, in addition to the control responsive to the position or inertia of the system as a whole, a second means for operating the control means.
(1) Note. The second control may be manual or operated in response to some other condition, such as pressure, temperature, etc.
(2) Note. This subclass also provides for systems including means to neutralize or overcome the effect of a change of position on a second flow control.
(3) Note. See the class definition, section 3, for search notes on combined automatic and manual control of fluid handling systems.
  
[List of Patents for class 137 subclass 40]    40Position relative body of water (e.g., marine governors):
 This subclass is indented under subclass 38.  Apparatus wherein the flow is controlled in response to the position of the system as a whole relative to a body of water in which the system is located.
(1) Note. To be classifiable in this or indented subclass the apparatus must include some means for sensing the position of the system relative to the body of water.
(2) Note. Marine governors operated in response to the shifting of the position of the system relative to gravity (due to ocean wave motion for example) but which do not include means for sensing the position of the system relative the water are found in other subclasses of this group.

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146,for the plunge or immersion starting of siphons.

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440Marine Propulsion,   subclass 74 for marine propulsion screw type propellers combined with propeller brakes to prevent racing of the propeller.
  
[List of Patents for class 137 subclass 41]    41Float controlled:
 This subclass is indented under subclass 40.  Apparatus which includes a float means for sensing the position of the system relative the body of water in which the system exists.

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386+,and Notes thereto for other float controlled apparatus.
  
[List of Patents for class 137 subclass 42]    42Pressure or head controlled:
 This subclass is indented under subclass 40.  Apparatus which includes means to sense the pressure or head of the body of water in which the system exists.

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403+,for liquid level responsive or maintaining systems in which the level is determined by head or pressure.
  
[List of Patents for class 137 subclass 43]    43Vent opening or closing on tipping container:
 This subclass is indented under subclass 38.  Apparatus including means to close or open a vent opening on a container when the position of the container is varied, e.g., when the container is tipped.

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583+,for distribution systems having plural flow passages, one of which is a gas vent, and see the search notes to subclass 583.

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222Dispensing,   subclass 500 for gravity or inertia actuated outlet elements for dispensers.
429Chemistry: Electrical Current Producing Apparatus, Product, and Process,   subclasses 84+ for vents combined with battery structure and battery vents, per se, of the nonspill type.
  
[List of Patents for class 137 subclass 44]    44By shifting of liquid level:
 This subclass is indented under subclass 38.  Apparatus wherein the control is effected by a change in a level of a liquid.

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40+,where the control is in response to a change or shift in the level of a body of water in which the system is located relative to the system.
45,for similar devices in which a liquid is employed as a shifting weight in combination with a pendulum or swinging member.
386+,for liquid level responsive systems which are not inertia controlled.
  
[List of Patents for class 137 subclass 45]    45By pendulum or swinging member:
 This subclass is indented under subclass 38.  Apparatus wherein the flow is controlled by means of a pendulum or other pivoted member swinging about its pivot in response to a change of position of the system or to the inertia of the system.

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33Geometrical Instruments,   subclasses 391+ for pendulum type levels or plumbs.
  
[List of Patents for class 137 subclass 46]    46With servo connection to valve:
 This subclass is indented under subclass 45.  Apparatus in which the pendulum or pivoted member controls the application of another source of power for operating the control instead of by acting directly through a mechanical connection.

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251Valves and Valve Actuation,   subclasses 25+ for fluid servo or pilot operated valves, and see the search notes to subclass 25.
  
[List of Patents for class 137 subclass 47]    47SPEED RESPONSIVE VALVE CONTROL:
 This subclass is indented under the class definition.  Systems including the combination of a valve or valves and an actuator therefor, the actuator including a driven means which changes its position or produces a regulating pressure which varies in accordance with the speed at which it is driven.
(1) Note. The driven means may comprise one or more governors.

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73Measuring and Testing,   subclasses 488+ for a speed responsive device, per se.
116Signals and Indicators,   subclasses 37+ and 57 for vehicle speed responsive indicators and subclasses 200+ for speed limit indicators.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
700Data Processing: Generic Control Systems or Specific Applications,   subclasses 282 through 285for flow control including valve or pump control, and subclasses 301 and 304 for pressure and speed control, respectively.
  
[List of Patents for class 137 subclass 48]    48Acceleration responsive valve control:
 This subclass is indented under subclass 47.  Control systems wherein the driven means changes its position in accordance with the rate of change of speed at which it is driven.
  
[List of Patents for class 137 subclass 49]    49With manual valve control:
 This subclass is indented under subclass 47.  Control systems including additional means whereby the valve or valves may be manually operated.
(1) Note. Manually operated means to modify the response setting of the speed responsive means or to reset the trip latch, are not deemed to constitute a manual control within the definition of this subclass. However, if the manual reset means also actuates the valve or valves, the device would be considered as being manually operated for classification herein. See the class definition, section 3, for search notes on combined automatic and manual control means for fluid handling systems, and Section 5, for a listing of manual control, resetting and adjusting devices in this class.
(2) Note. The term "manual" as used herein includes both hand and foot actuated means.
(3) Note. This subclass includes manual valve actuating means in which a speed responsive device become effective at a predetermined speed of the engine or vehicle, either (1) to disconnect the mechanical movement of the manual actuator, and in some instances also to operate a trip mechanism to permit a biasing means to close the valve, or (2) to act as a limit stop to prevent further valve opening by the manual actuator.

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57,for excess speed responsive control, and see the search notes thereto.

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73Measuring and Testing,   subclass 513 for a speed responsive device combined with manual control.
  
[List of Patents for class 137 subclass 50]    50Speed change and excess speed valve control:
 This subclass is indented under subclass 47.  Control systems wherein the driven means is operable to vary the extent of opening of the valve or valves in response to changes in speed and to effect closing of the valve or valves in response to a speed above a predetermined speed.
(1) Note. The driven means may comprise one or more governors which may control a single valve or a plurality of valves.

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57,for excess speed responsive valve control of the centrifugal mass type, and see the search notes thereto.
  
[List of Patents for class 137 subclass 51]    51With other condition responsive valve control:
 This subclass is indented under subclass 47.  Control systems including additional means responsive to another operating condition which may actuate the same valve which is actuated by the speed responsive means, or another valve.

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73Measuring and Testing,   subclass 509 for a speed responsive device that is also responsive to a nonspeed condition.
  
[List of Patents for class 137 subclass 52]    52Governor drive failure responsive:
 This subclass is indented under subclass 51.  Control systems wherein the additional condition responsive means comprises a control device responsive to the breaking or failure of the driving means for the speed responsive governor to effect closing or substantial closing of a valve.
(1) Note. The valve which is closed or substantially closed on failure of the driving means may be the valve controlled by the speed responsive governor or another valve.

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73Measuring and Testing,   subclass 508 for a governor having drive failure responsive means.
251Valves and Valve Actuation,   subclass 27 for fluid pressure servo operated valves having means to close the valve on failure of the servo means, and subclass 69 for biased trip valves having the trip actuated on failure of the electric power.
  
[List of Patents for class 137 subclass 53]    53Centrifugal mass type (exclusive of liquid):
 This subclass is indented under subclass 47.  Control systems wherein the speed responsive means comprises a rotating or revolving weight or weights, the position assumed by such weight or weights due to centrifugal force varying as a function of the speed at which they are rotated or revolved.

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73Measuring and Testing,   subclasses 535+ for a centrifugal type speed responsive device, per se.
  
[List of Patents for class 137 subclass 54]    54With multiple valves:
 This subclass is indented under subclass 53.  Control systems wherein two or more valves are provided, at least one of said valves being actuated by the speed responsive means.
(1) Note. See the class definition, section 3, for search notes on plural automatic valves in this and related classes.
  
[List of Patents for class 137 subclass 55]    55Periodically actuated valve:
 This subclass is indented under subclass 53.  Control systems wherein the valves or valve are periodically and continually opened and closed, the governor being effective to vary the period and/or the extent of opening.
(1) Note. The valves are usually disclosed for use in a reciprocating type of expansible chamber motor, the valves being periodically actuated for admitting motive fluid to the power cylinder and the governor varies the quantity of motive fluid in accordance with the motor speed.

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631+,for nonautomatic cyclically operated valves, and see the search notes to subclass 631.
  
[List of Patents for class 137 subclass 56]    56Rotating valve and rotating governor:
 This subclass is indented under subclass 53.  Control systems wherein the speed responsive means and the valve or valves are combined to comprise a continuously rotating construction.

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55,for valves connected with a speed responsive governor to rotate therewith in order to periodically open and close the valve, the governor producing an axial motion of the valve to control the period and/or extent of valve openings.
  
[List of Patents for class 137 subclass 57]    57Excess speed responsive:
 This subclass is indented under subclass 53.  Control systems wherein the speed responsive means is effective to actuate the valve or valves only at speeds above a predetermined speed.

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50,for speed change and excess speed valve control.
456+,for safety cut-offs of general utility which respond to line condition and require resetting.

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116Signals and Indicators,   subclass 57 and 62.1+ for vehicle speed limit indicators and alarms.
  
[List of Patents for class 137 subclass 58]    58With fluid servo-motor:
 This subclass is indented under subclass 53.  Control systems wherein the speed responsive means transmits its regulating motion to the valve or valves by means of a fluid type servo-motor mechanism.

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91Motors: Expansible Chamber Type,   subclasses 366 and 458 for speed governor operated expansible chamber motors.
251Valves and Valve Actuation,   subclasses 25+ for fluid pressure actuated valves of the pilot or servo-motor type, and see the search notes to subclass 25.
418Rotary Expansible Chamber Devices,   subclasses 40+ for speed controlled rotary expansible chamber devices.
  
[List of Patents for class 137 subclass 59]    59FREEZE CONDITION RESPONSIVE SAFETY SYSTEMS:
 This subclass is indented under the class definition.  Apparatus which includes means which senses the existence of conditions which would cause the freezing of liquid within the system and in response thereto exercises a control to protect the liquid from freezing or to safeguard the system as a whole from the effects of freezing of a part thereof.

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72+,for valves controlled by heat destructible or fusible means.
79+,for devices responsive to atmospheric temperature not amounting to a freeze condition.
107,for apparatus wherein a waste valve opens in response to the stopping of flow through the line, disclosed as preventing freezing.
118.01+,for branched flow systems responsive to temperature of the system.
301+,for hydrants with means to prevent freezing.
457,for safety cut-offs requiring reset and responsive to thermal conditions in a fluid line.
468,for other valves controlled in response to thermal conditions in a fluid line.

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62Refrigeration,   subclasses 132+ for condition sensing controls for a refrigeration system, particularly subclasses 139+ for control by accumulation on a freezing surface.
123Internal-Combustion Engines,   subclasses 41.14 , 41.15, 41.42, 41.5, and 142.5 for devices for protecting the cooling systems of internal combustion engines against cold.
138Pipes and Tubular Conduits,   subclasses 27+ for freeze protecting pressure compensators, and subclasses 32+ for freeze protection for pipes and tubular conduits.
236Automatic Temperature and Humidity Regulation,   appropriate subclasses.
237Heating Systems,   subclass 80 for heating radiators having means for preventing freezing.
  
[List of Patents for class 137 subclass 60]    60With freeze waste:
 This subclass is indented under subclass 59.  Apparatus which includes means to protect the liquid from freezing by responding to the freezing of the liquid in a chamber.
(1) Note. The freeze chamber may be in the main flow line or may be an auxiliary control chamber which is more exposed to the low temperature.

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67+,for frangible control elements not responsive to a freeze condition.
  
[List of Patents for class 137 subclass 61]    61Stop and waste:
 This subclass is indented under subclass 59.  Apparatus which closes the system to liquid flow and opens a waste outlet so that at least part of the liquid in the system is drained or wasted in response to the sensing of low temperature or freezing conditions.

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107,for opening fluid waste passage in response to stopping of the main flow.
596+,for stop and waste devices not responsive to change in condition, and see the search notes thereto.
  
[List of Patents for class 137 subclass 62]    62Low temperature responsive drains:
 This subclass is indented under subclass 59.  Apparatus which operates to open an outlet so that at least part of the system is drained or emptied of liquid in response to the sensing of low temperature or freezing conditions.

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570,for drain valve actuator combined with a pump.
596+,for distribution systems comprising a drain which is not automatic, and see the search notes thereto.
  
[List of Patents for class 137 subclass 65]    65COMBUSTION FAILURE RESPONSIVE FUEL SAFETY CUT-OFF FOR BURNERS:
 This subclass is indented under the class definition.  Subject matter comprising a flow control device or safety valve in the fuel supply to a burner which is automatically actuated to discontinue the fuel flow in response to the extinguishment of the main or pilot burner.
(1) Note. These devices are not self-opening, but must be manually reset, usually requiring that the pilot burner be lighted first.

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405,for cut-offs responsive to an accumulation of unburned fuel oil delivered to a burner.
456+,for safety cut-offs responsive to a change in line condition, which also require resetting.

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431Combustion,   subclasses 42+ for a burner system in which the sensor of a first burner controls a second burner and subclasses 77+ for a burner shutdown by a means sensing a failure of the burner flame.
  
[List of Patents for class 137 subclass 66]    66Thermo-electric:
 This subclass is indented under subclass 65.  Control systems wherein the safety valve is retained in its set or open position under the action of a solenoid, which solenoid is energized by the electric current generated by a thermoelectric element, e.g., a thermocouple, subject to the heat of the pilot burner or main burner.

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251Valves and Valve Actuation,   subclass 11 for heat motor actuated valves of general utility, and subclasses 68+ for electrical trip actuation of biased valves, including electrical resetting.
431Combustion,   subclass 80 for a burner assembly including a shutdown control responsive to combustion failure or overheat having a thermoelectric combustion sensor.
  
[List of Patents for class 137 subclass 67]    67DESTRUCTIBLE OR DEFORMABLE ELEMENT CONTROLLED:
 This subclass is indented under the class definition.  Subject matter in which the flow of fluid is controlled in response to the destruction, fusion or permanent deformation of an element or body.
(1) Note. The destruction, fusion or deformation may result automatically in response to the existence of some condition causing destruction, fusion or deformation (e.g., heat), or may be deliberately brought about by external means.

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318,for tapping a system under pressure by making an aperture therein.

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166Wells,   subclasses 316+ for closures used in wells and destructible by drilling.
222Dispensing,   subclass 54 for automatic control of dispensers by fusible or soluble means; subclasses 80+ for dispensers having a cutter or punch associated therewith; subclasses 541.1+ for dispensers having a frangible outlet element.
251Valves and Valve Actuation,   subclass 1.2 for a blowout preventer having a deformable annulus.
  
[List of Patents for class 137 subclass 68.11]    68.11Destructible element:
 This subclass is indented under subclass 67.  Subject matter in which the fluid flow control element is physically broken by having a force acting directly upon it.

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797,for frangible elements, the breaking of which do not control any flow of fluid.

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222Dispensing,   subclasses 80+ for dispensers having a cutter or punch associated therewith.
  
[List of Patents for class 137 subclass 68.12]    68.12Combined destructible and fusible element:
 This subclass is indented under subclass 68.11.  Subject matter in which the element breaks and melts at a specific temperature to control the fluid flow or has, in addition to the destructible element, a separate element which melts at a specific temperature to control the fluid flow.
  
[List of Patents for class 137 subclass 68.13]    68.13Explosive actuation:
 This subclass is indented under subclass 68.11.  Subject matter which includes means capable of detonation for creating a force for breaking or deforming the destructible element (e.g., an explosive element moves a plunger or creates a pressure surge to break the element).
  
[List of Patents for class 137 subclass 68.14]    68.14Separable valve coupling or conduit:
 This subclass is indented under subclass 68.11.  Subject matter where the destructible element is a fluid-conveying assembly such as a nipple, valve assembly, or hose that disconnects at a specific joint when an excessive force is applied to it.
  
[List of Patents for class 137 subclass 68.15]    68.15Tensile or sheer pin or bolt:
 This subclass is indented under subclass 68.14.  Subject matter where the destructible element is a pin or bolt that holds the coupling together and destructs when a perpendicular or axial excessive force is applied to the coupling.
  
[List of Patents for class 137 subclass 68.16]    68.16Tensile or sheer pin or bolt:
 This subclass is indented under subclass 68.11.  Subject matter where the destructible element is a pin or bolt that destructs when an excessive force is applied.
  
[List of Patents for class 137 subclass 68.17]    68.17Pressure causes pin or bolt to destruct:
 This subclass is indented under subclass 68.16.  Subject matter that destructs when the applied excessive force that fractures the pin or bolt is applied over the surface of the pin or bolt.
  
[List of Patents for class 137 subclass 68.18]    68.18With alarm or indicator:
 This subclass is indented under subclass 68.11.  Subject matter that includes a sensing means that sends a signal when the element breaks.
  
[List of Patents for class 137 subclass 68.19]    68.19Rupture disc:
 This subclass is indented under subclass 68.11.  Subject matter where the destructible element is a diaphragm or seal that holds fluid.

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72,for a fluid-controlled fusible diaphragm.

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220Receptacles,   subclasses 89.2+ for a receptacle that is a frangible diaphragm within a container or vessel.
  
[List of Patents for class 137 subclass 68.21]    68.21Means for holding entire disc after rupture:
 This subclass is indented under subclass 68.19.  Subject matter that has a specific means for preventing the rupture disc from tearing away (e.g., hinge-reinforcing member).
  
[List of Patents for class 137 subclass 68.22]    68.22Disc burst after destruction of additional element:
 This subclass is indented under subclass 68.19.  Subject matter that includes a second frangible element in a system which destructs before the rupture disc.
(1) Note. This subject matter would include a system with two or more rupture discs in a flow passage.
  
[List of Patents for class 137 subclass 68.23]    68.23Direct pressure causes disc to burst:
 This subclass is indented under subclass 68.19.  Subject matter wherein the destructible element is destroyed by excessive pressure exerted by the fluid flow.
  
[List of Patents for class 137 subclass 68.24]    68.24Two-way rupture disc:
 This subclass is indented under subclass 68.23.  Subject matter that is designed to break either in the direction of or opposite the direction of the fluid flow when an excessive pressure differential exists.
  
[List of Patents for class 137 subclass 68.25]    68.25Dome shape:
 This subclass is indented under subclass 68.23.  Subject matter that is specifically designed to be hemispherical to enable the disc to more easily rupture as pressure builds.
  
[List of Patents for class 137 subclass 68.26]    68.26Reverse buckling:
 This subclass is indented under subclass 68.25.  Subject matter which has excessive pressure at the convex side of the disc to cause the disc to reverse its concavity and burst.
  
[List of Patents for class 137 subclass 68.27]    68.27Specific weakening point:
 This subclass is indented under subclass 68.19.  Subject matter specially modified to have an area of varied thickness creating a vulnerable section to enable the pressure disc to more easily break.
  
[List of Patents for class 137 subclass 68.28]    68.28Integral disc assembly:
 This subclass is indented under subclass 68.19.  Subject matter including a support member welded or bonded with adhesive to the rupture disc or the rupture disc is directly bonded or welded to the assembly.
  
[List of Patents for class 137 subclass 68.29]    68.29Knife or cutter causes disc to break:
 This subclass is indented under subclass 68.19.  Subject matter penetrated by a piercing device to enable the disc to more easily break when the internal pressure in the system becomes excessive.
  
[List of Patents for class 137 subclass 68.3]    68.3Movable knife or cutter:
 This subclass is indented under subclass 68.29.  Subject matter wherein the piercing device is positionable.
  
[List of Patents for class 137 subclass 69]    69With counterbalancing element:
 This subclass is indented under subclass 68.12.  Apparatus which includes means for applying a force or bias to the frangible means in a direction opposing the force (usually fluid pressure) which tends to break the frangible element.
  
[List of Patents for class 137 subclass 70]    70Frangible element returns pressure responsive valve:
 This subclass is indented under subclass 68.12.  Apparatus in which a valve which opens in response to increased pressure is retained in closed position by means of a frangible element, opening of the valve resulting from the breaking of the frangible element.

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455+,for line condition responsive valves not opposed by frangible means.
  
[List of Patents for class 137 subclass 71]    71Having pressure responsive valve:
 This subclass is indented under subclass 68.12.  Apparatus including a pressure responsive valve controlling the fluid flow in response to the pressure thereof in addition to the control in response to the breaking of the frangible element.

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511+,for direct pressure responsive valves.

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220Receptacles,   subclass 203.08 for a vent or valve in a removeable closure, said vent or valve designed to rupture when exposed to excessive pressure.
  
[List of Patents for class 137 subclass 72]    72Heat destructible or fusible:
 This subclass is indented under subclass 67.  Apparatus in which the flow is controlled in response to an element which is fusible or destructible by heat (e.g., combustible).

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79+,for atmospheric temperature responsive flow control.
457,for safety cut-off valves controlled by a thermal condition of the line.
468,for other valves controlled by a thermal condition of a fluid line.

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116Signals and Indicators,   subclasses 217+ for indicators of the fusible type.
122Liquid Heaters and Vaporizers,   subclass 504.1 for safety device for a boiler with fusible control and subclass 504.3 for a fusible type safety device extinguishing a fire under a boiler.
222Dispensing,   subclass 54 for dispensers having a fusible controller.
431Combustion,   subclass 21 for a burner assembly controlled by a combustion destructible element.
  
[List of Patents for class 137 subclass 73]    73With second sensing means:
 This subclass is indented under subclass 72.  Apparatus which includes a means for controlling the fluid flow in response to a change in condition in addition to the control in response to the fusion or destruction of the heat destructible element.
(1) Note. See the class definition, section 3 for search notes on plural automatic controls in fluid handling devices.

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75+,for safety cut-offs operated by fusible means but without responding to a second sensing means.
  
[List of Patents for class 137 subclass 74]    74In fluid flow path:
 This subclass is indented under subclass 72.  Apparatus in which the fusible or heat destructible element is in the passage carrying the flow controlled and functions as a barrier or stop member for such flow.
(1) Note. The fusion of the fusible element may result in either the opening or closing of the passage carrying the fluid flow.

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251+,for liquid valves or barriers.
  
[List of Patents for class 137 subclass 75]    75Safety cut-off:
 This subclass is indented under subclass 72.  Apparatus in which the valve controlling the fluid flow is biased toward a closed position but is held open by a restraining means, the fusion or destruction of the heat destructible or fusible means causing a release of the restraining means.

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457,for other cut-offs which are operated in response to a change in thermal condition in the fluid within the controlled line.

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251Valves and Valve Actuation,   subclasses 66+ for biased trip valve actuators not responsive to a condition change.
  
[List of Patents for class 137 subclass 76]    76With heater for destructible or fusible element:
 This subclass is indented under subclass 75.  Apparatus which includes a heating means for the fusible or heat destructible element.
(1) Note. The heating element is usually for the purpose of fusing or otherwise destroying the destructible element to control the operation of the valve.

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468,for line condition responsive valves controlled by thermal conditions, and see the search notes thereto.

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251Valves and Valve Actuation,   subclass 11 for heat motor actuators for valves.
  
[List of Patents for class 137 subclass 77]    77With external closing means:
 This subclass is indented under subclass 75.  Apparatus including a means for closing the valve by manual or external means in addition to the operation in response to the fusible or heat destructible element.
(1) Note. See the class definition, Automatic Control, and Subclass References to the Current Class for search notes on combined automatic and nonautomatic control of a fluid handling device.

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76,for manual or external closing by heating the fusible or heat destructible element.

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251Valves and Valve Actuation,   subclasses 66+ for biased trip valve actuators not responsive to a condition change.
  
[List of Patents for class 137 subclass 78.1]    78.1AMBIENT CONDITION CHANGE RESPONSIVE:
 This subclass is indented under the class definition.  Apparatus which controls a flow of a fluid in response to a variation in a condition of, or in the surrounding environment.
(1) Note. To be classifiable in this or indented subclasses the apparatus must include a sensing means responsive to changes in environmental conditions and there must be a disclosure that the control is in response to such changes. Devices which employ a sensing means using environmental pressure merely as a standard against which some internal pressure or condition is measured are not classified in this or indented subclass but are classified elsewhere on a basis appropriate to the system.
(2) Note. This and indented subclasses include devices which include means for sensing changes in an environmental condition and exercising a compensating effect so as to neutralize any effect the change in environmental condition would otherwise have on the operation of the device.
(3) Note. See the class definition, section 3, for search notes on the automatic control of fluid handling systems.

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59+,for device which sense the existence of freeze condition in the atmosphere and in response thereto operate to prevent freezing of liquid in the system.
  
[List of Patents for class 137 subclass 78.2]    78.2For controlling soil irrigation:
 This subclass is indented under subclass 78.1.  Apparatus in which flow of water to the ground is controlled by means responsive to an environmental condition.
  
[List of Patents for class 137 subclass 78.3]    78.3Coil moisture sensing:
 This subclass is indented under subclass 78.2.  Apparatus in which flow of water to the ground is controlled in response to a change in moisture content of the ground.
  
[List of Patents for class 137 subclass 78.4]    78.4Burner gas cutoff:
 This subclass is indented under subclass 78.1.  Apparatus in which flow of flammable gas to a burner is stopped in response to a sensed environmental extinguishing action to the flame of the burner.
  
[List of Patents for class 137 subclass 78.5]    78.5Atmospheric:
 This subclass is indented under subclass 78.1.  Apparatus in which control of a flow of fluid is responsive to a variation in a condition of, or in surrounding atmosphere.
  
[List of Patents for class 137 subclass 79]    79Temperature:
 This subclass is indented under subclass 78.5.  Apparatus which controls a fluid flow in response to variations of temperature in the surrounding atmosphere.
(1) Note. This subclass includes apparatus which sense the presence of a fire in the atmosphere and exercise a control in response thereto.

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59+,for freeze condition responsive safety devices.
67+,for systems controlled by a heat destructible or fusible means.
468,for thermally responsive valves responding to line condition change, and see the search notes thereto.

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169Fire Extinguishers,   subclasses 56+ for fire extinguishers including valves responsive to the occurrence of fire conditions.
  
[List of Patents for class 137 subclass 80]    80With additional diverse control:
 This subclass is indented under subclass 79.  Apparatus which also includes, in addition to the atmosphere temperature responsive element, an additional means for operating the control means.
(1) Note. See the class definition, Section 3 for search notes on automatic and combined automatic and nonautomatic control of fluid handling systems.
  
[List of Patents for class 137 subclass 81.1]    81.1Pressure:
 This subclass is indented under subclass 78.5.  Apparatus in which a fluid flow is controlled in response to variations of atmospheric pressure.
(1) Note. See (1) Note and (2) Note to the definition of subclass 78.1.

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455+,for valves controlled by changes in line pressure, especially subclass 482 for suction compensators for combustion engine induction type line conduction change responsive valves.

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454Ventilation,   subclasses 70+ , 238, 255, and 340 for apparatus for maintaining a pressure in enclosure including means responsive to air conditions either in the atmosphere or in the enclosure.
  
[List of Patents for class 137 subclass 81.2]    81.2Underwater:
 This subclass is indented under subclass 78.1.  Apparatus in which control of a flow of fluid is responsive to a variation in a condition of, or in an environment beneath the surface of a body of water.
  
[List of Patents for class 137 subclass 82]    82PRESSURE MODULATING RELAYS OR FOLLOWERS:
 This subclass is indented under the class definition.  Apparatus which continuously varies or modulates a fluid in response to a varying control condition. The modulation is usually accompanied by varying a pressure bleed.
(1) Note. Only the subcombination, without a pressure responsive device, and a main valve controlled thereby is classified in this subclass; for the combination search appropriate succeeding subclasses, as indicated below.

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102,for pressure regulators which regulate by supply and exhaust valves to maintain a pre-set pressure.

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91Motors: Expansible Chamber Type,   appropriate subclasses for apparatus under this definition combined with the expansible chamber motor which is operated by the fluid pressure.
236Automatic Temperature and Humidity Regulation,   subclasses 79+ for temperature control systems utilizing pressure modulators to operate fluid pressure motors.
251Valves and Valve Actuation,   subclasses 25+ for apparatus which by means of a pilot valve controls the application of fluid pressure to an expansible chamber motor which in turn controls a main line valve.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 83]    83Jet control type:
 This subclass is indented under subclass 82.  Apparatus which utilize a fluid jet and one or more jet receiving orifices with the control condition varying the pressure in the orifices by varying the amount of jet fluid entering the orifices.

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625.6,for a jet control type pressure modulator combined with a pilot valve and a supply and exhaust valve.

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91Motors: Expansible Chamber Type,   subclass 3 for expansible chamber motors combined with a jet type control therefor.
239Fluid Sprinkling, Spraying, and Diffusing,   appropriate subclasses, especially subclasses 505+ , 518+ and 587.1+ for jet producing discharge members, per se.
  
[List of Patents for class 137 subclass 84]    84Plural series units:
 This subclass is indented under subclass 82.  Apparatus wherein a plurality of modulating relays on followers are connected in series; the output pressure of one controlling the modulation in the next.
  
[List of Patents for class 137 subclass 85]    85With counter-balancing pressure feedback to the modulating device:
 This subclass is indented under subclass 82.  Apparatus in which the modulated pressure is utilized in a feedback arrangement to counterbalance the modulating control element.
  
[List of Patents for class 137 subclass 86]    86With counter-counter balancing pressure feedback:
 This subclass is indented under subclass 85.  Apparatus in which the modulated pressure is utilized in a second feedback arrangement to counterbalance the counterbalance of the modulating control element.
  
[List of Patents for class 137 subclass 87.01]    87.01SELF-PROPORTIONING OR CORRELATING SYSTEMS:
 This subclass is indented under the class definition.  Subject matter wherein a fluid flow in a first flow line is proportioned or correlated with the fluid flow in a second fluid flow line by a movable means, which is positioned in one of the fluid flow lines and controlling the fluid flow in the other fluid flow line in response to a sensor detecting a variable condition or characteristic of the fluid in the other fluid flow line.
(1) Note. The flow proportioning or correlating may constitute plural separate flow lines, branches of the same flow and a branch thereof.
(2) Note. The proportioning and correlating of the fluid flows may be continuous or discontinuous and may vary directly or inversely and according to any ratio or in any manner.
(3) Note. Systems that rely on static means (e.g., a jet pump) to produce a correlated flow are excluded.

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155,for gas lift devices for wells including a valve between a gas line and a liquid column responsive to the pressure differential between the gas and the liquid.

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210Liquid Purification or Separation,   subclasses 198.1+ for a system including a chemical feeder and a separating means.
222Dispensing,   subclass 57 for dispensing of one material controlled by the weight, volume, or pressure of a second dispensed material.
251Valves and Valve Actuation,   subclasses 12+ for mere fluid pressure actuated valves, even though the flow through the valve may be disclosed as being related or proportioned to the pressure in the fluid pressure actuator line.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 87.02]    87.02Liquid level responsive:
 This subclass is indented under subclass 87.01.  Subject matter wherein the sensor is detecting the variation in an uppermost horizontal surface of the liquid in one of the flow lines and in response thereto the sensor controls the flow in the other flow line.

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101.25,for a self-proportioning flow system with liquid level sensing.
386+,for a liquid level responsive means without proportionate or correlated flow.
  
[List of Patents for class 137 subclass 87.03]    87.03Flow rate responsive:
 This subclass is indented under subclass 87.01.  Subject matter wherein the sensor is detecting the variation in the amount of fluid flowing in one of the flow lines in a set period of time or is detecting the variation in fluid pressure (i.e., pressure differential) along the flow line and in response thereto the sensor controls the flow in the other flow line.
  
[List of Patents for class 137 subclass 87.04]    87.04Pressure differential:
 This subclass is indented under subclass 87.03.  Subject matter wherein the sensor is detecting the variation of the fluid pressures at two distinct points along one of the flow lines and in response thereto the sensor controls the flow in the other flow line.

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101,for the self-proportioning flow system responsive to flow comparison or pressure differential.
  
[List of Patents for class 137 subclass 87.05]    87.05Plural sensors:
 This subclass is indented under subclass 87.01.  Subject matter including two or more sensors for detecting two distinct or similar conditions or characteristics of the fluid in one of the flow lines and in response thereto the sensors control the flow in the other flow line.
  
[List of Patents for class 137 subclass 87.06]    87.06For single valve:
 This subclass is indented under subclass 87.05.  Subject matter comprising one valve element and wherein the sensors operate only one valve element to control the flow.
  
[List of Patents for class 137 subclass 88]    88Mixture condition maintaining or sensing:
 This subclass is indented under subclass 87.01.  Systems in which a condition of a fluid mixture is maintained by controlling the flow of at least one of the fluids mixed in response to a means which sense the condition of the mixture.

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3+,for the corresponding processes.
  
[List of Patents for class 137 subclass 89]    89Dividing and recombining flow:
 This subclass is indented under subclass 88.  Systems in which a fluid flow is divided into a plurality of flow paths which are subsequently recombined, the ratio of the flows thus divided and recombined being controlled in response to a means sensing a condition to be maintained.
(1) Note. This subclass includes, for example, systems in which one of the plurality of flow paths pass through a means to treat the fluid to restore the property to be maintained, the amount of fluid passing through the treating means being controlled by the condition sensing means.

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599.01through 601.21, for systems dividing into parallel flow lines then recombining.
  
[List of Patents for class 137 subclass 91]    91By specific gravity:
 This subclass is indented under subclass 88.  Systems in which the condition maintained or sensed is specific gravity.

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403+,for systems in which a single flow is controlled by weight of an accumulated fluid, and see the search notes to subclass 403.
  
[List of Patents for class 137 subclass 92]    92By viscosity or consistency:
 This subclass is indented under subclass 88.  Systems in which the condition maintained or sensed is viscosity or consistency.
(1) Note. Due to their similarity with systems classified in this subclass, systems are also included in which the viscosity or consistency of a stream is sensed and in response thereto the subsequent addition of water is controlled in order to produce a predetermined or desired viscosity or consistency.

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4,for the corresponding process.

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162Paper Making and Fiber Liberation,   subclasses 258 and 380 for systems for maintaining the consistency or viscosity of paper making pulp combined with paper making apparatus.
  
[List of Patents for class 137 subclass 93]    93By optical or chemical property:
 This subclass is indented under subclass 88.  Systems in which the condition maintained or sensed is an optical or chemical property.

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5,for processes of controlling flow according to the conductivity of the mixture.
392,for control of a single fluid flow by sensing electrical characteristics.

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250Radiant Energy,   subclasses 200+ for photocell circuits.
356Optics: Measuring and Testing,   for examination of material by light for optical properties particularly subclasses 128+ for refraction tests, subclasses 410+ for shade or color tests involving flowing liquids, and subclasses 432+ for light transmission tests involving gases or liquids.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 50+ for chemical analyzers; and subclasses 105+ for apparatus operating in response to a sensed condition.
  
[List of Patents for class 137 subclass 94]    94Fuel controlled by boiler or water system condition:
 This subclass is indented under subclass 87.01.  Subject matter in which a condition of the fluid in a boiler or water heating system controls the flow of fuel used for heating the boiler or water.

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386+,for liquid level responsive or maintaining systems.
468,for thermally responsive controllers, and see the search notes thereto.

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122Liquid Heaters and Vaporizers,   subclasses 448.1 through 448.4for automatic control of fluid fuel and feed water to a boiler.
  
[List of Patents for class 137 subclass 98]    98Self-proportioning flow systems:
 This subclass is indented under subclass 87.01.  Systems in which the control means maintains a predetermined ratio between flows in a plurality of flow lines.
(1) Note. The flows may be separate or may subsequently be combined or may be branches from a single source of a fluid.

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577through 579, for systems having a tank with movable or adjustable outlet or overflow pipe.
599.01through 601.21, for systems dividing into parallel flow lines then recombining.
861through 887, for systems having flow control means for branched passages.

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73Measuring and Testing,   subclasses 195+ for rate of flow meter systems employing two or more meters usually for measuring and comparing a plurality of flows.
210Liquid Purification or Separation,   subclass 101 for proportionate feed means combined with separating means.
261Gas and Liquid Contact Apparatus,   appropriate subclass for gas and liquid contact devices including means for maintaining a proportional flow between a gas and liquid; see particularly subclasses 69.1+ for systems in which the flow of liquid is controlled in response to the rate of flow in the gas line as measured by means of a venturi in the gas line.
  
[List of Patents for class 137 subclass 99]    99Interconnected flow displacement elements:
 This subclass is indented under subclass 98.  Systems in which the proportioning or correlating means includes mechanically interconnected flow displacement elements.
(1) Note. Flow displacement elements include primarily pump and meter arrangements and vanes or other elements exposed to the flow and shifted in response to variations therein, such shifting elements usually acting both as controlling and detecting means.

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565+,for nonautomatic distribution systems including pumps.
  
[List of Patents for class 137 subclass 99.5]    99.5Movable trap chamber:
 This subclass is indented under subclass 99.  Subject matter wherein the flow displacement element comprises a bodily movable measuring chamber which provides continuous flow with increment feeding.

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101.31,for a stationary measuring chamber.

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222Dispensing,   subclasses 344+ for systems wherein the movable discharge assistant is not related to a continuous flow, and see the search notes thereunder.
  
[List of Patents for class 137 subclass 100]    100Flow comparison or differential response:
 This subclass is indented under subclass 98.  Systems in which the sensing means is sensitive to the differences between the rates of flow or pressure difference along the line in a plurality of flow lines or at spaced points along one line.
(1) Note. Means sensing changes in the difference between the flows may control the flow in a third flow line or may exercise a control on the flows compared.

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497+,for line change condition responsive valves controlled by change in the rate of flow, and see the search notes to subclass 497.
  
[List of Patents for class 137 subclass 101]    101Flow dividers (e.g., reversely acting controls):
 This subclass is indented under subclass 100.  Systems in which a flow is divided into a plurality of flow paths and the ratio between the flow in each branch maintained in response to means sensing differences in flow or pressure in each branch by throttling one branch an amount equal to the amount the other branch is opened.
(1) Note. Many of the patents in this subclass are for systems in which a single pressure fluid is employed to supply a plurality of fluid pressure motors with means to automatically maintain the amounts of fluid fed to each motor proportional.

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60Power Plants,   subclasses 420+ for automatic control of a plurality of fluid motors.
91Motors: Expansible Chamber Type,   appropriate subclasses and especially subclasses 165+ and 508+ for automatic control of a plurality of expansible chamber motors.
  
[List of Patents for class 137 subclass 101.11]    101.11Main line flow displaces or entrains material from reservoir:
 This subclass is indented under subclass 100.  Subject matter wherein a shunt line having a reservoir therein relies on the pressure difference between its connection to the main line to cause flow therethrough to entrain material in the reservoir, or to displace the reservoir material or an intermediate distinct fluid layer or expansible chamber device whereby the reservoir material is forced into the main line without mixing with the flow while in the shunt.
  
[List of Patents for class 137 subclass 101.19]    101.19With electrical controller:
 This subclass is indented under subclass 100.  Subject matter comprising an electrical controller responsive to the sensing means.

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251Valves and Valve Actuation,   subclasses 129+ for an electrical valve actuator.
  
[List of Patents for class 137 subclass 101.21]    101.21Flow displacement element actuates electrical controller:
 This subclass is indented under subclass 98.  Subject matter comprising an electrical controller responsive to a flow displacement element.
  
[List of Patents for class 137 subclass 101.25]    101.25Liquid level response:
 This subclass is indented under subclass 98.  Subject matter comprising at least one means which senses the level of a liquid in means to receive an accumulation thereof and in response thereto exercises a control of the flow in one or more of the flow lines.

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386+,for liquid level responsive means without proportionate or correlated flow. See the search notes thereunder.
  
[List of Patents for class 137 subclass 101.27]    101.27Float controlled weir or valve:
 This subclass is indented under subclass 101.25.  Subject matter wherein a weir or valve is responsive to the level sensing means.
  
[List of Patents for class 137 subclass 101.29]    101.29Swinging outlet pipe controller:
 This subclass is indented under subclass 101.25.  Subject matter wherein a swinging outlet pipe controls the flow from an accumulator or tank responsive to the level sensing means.

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577+,for a tank with a movable or adjustable outlet or overflow pipe.
  
[List of Patents for class 137 subclass 101.31]    101.31With measuring type discharge assistant:
 This subclass is indented under subclass 98.  Subject matter comprising a measuring type discharge assistant in one flow line responsive to a flow displacement element in another flow line or by the weight of accumulated fluid of a proportionate part of the flow in another line to provide continuous flow through the system with increment feeding.

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222Dispensing,   subclasses 261+ for dispensing apparatus with discharge assistants.
  
[List of Patents for class 137 subclass 102]    102Supply and exhaust type:
 This subclass is indented under subclass 87.01.  Systems in which an outlet or receiver alternatively receives a fluid from a source of supply and drains the fluid to an exhaust, the flow of fluid from the supply or to the exhaust, being controlled in response to a means sensing a change in condition.
(1) Note. Many of the patents classified in this subclass are drawn to distributor valves for fluid motors.

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224+,for tire inflation apparatus which may have condition responsive filling and relief valves
596+,for distribution systems involving stop and waste arrangements, and see the search notes thereto.

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91Motors: Expansible Chamber Type,   appropriate subclasses for apparatus under this definition combined with an expansible chamber motor which is controlled thereby.
  
[List of Patents for class 137 subclass 103]    103Vacuum or suction pulsator type (e.g., milking machine):
 This subclass is indented under subclass 102.  Systems in which an outlet or receiver is alternately connected to a source of suction or vacuum and a source of fluid under pressure or vent (usually the atmosphere).
(1) Note. Many of the patents classified in this subclass are for milking machine pulsators.

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526,for vacuum relief valves of the type responding to fluid pressure exerted directly on the valve face.

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119Animal Husbandry,   subclasses 14.01+ for milking machines.
  
[List of Patents for class 137 subclass 104]    104With trip linkage or snap action:
 This subclass is indented under subclass 103.  Apparatus which include a snap acting or trip linkage in the control system.

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251Valves and Valve Actuation,   subclasses 66+ for valves with biased trips, and see the search notes to subclass 66, and subclass 76 for snap action valves, per se, and see the search notes thereto.
  
[List of Patents for class 137 subclass 105]    105With pulsation responsive pilot valve:
 This subclass is indented under subclass 103.  Apparatus wherein the flow controlling valve is moved by a fluid servo under control of a second valve which is itself fluid operated under control of the first valve, there being no mechanical linkage between the two valves.

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488+,for line condition change responsive fluid pressure type servo or pilot controlled valves.

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251Valves and Valve Actuation,   subclasses 28+ for fluid servo or pilot actuated valves having fluid actuated pilot valve.
  
[List of Patents for class 137 subclass 106]    106Reversing or 4-way valve systems:
 This subclass is indented under subclass 102.  Systems which include two outlets or receivers, one outlet or receiver being connected to the supply while the other is connected to the exhaust, the connections being reversed or changed in response to a means sensing a change in condition.
(1) Note. Many of the patents classified in this subclass are drawn to distributor valves for plural expansible chamber motors.

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625+,for multiway valve units and their actuators, and see the search notes to subclass 625.
  
[List of Patents for class 137 subclass 107]    107Waste responsive to flow stoppage:
 This subclass is indented under subclass 102.  Systems wherein a waste or drain is opened in response to the stopping of the fluid flow from the supply to the outlet or receiver.

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61,for stop and waste systems which are responsive to means sensing freeze conditions.
596+,for stop and waste systems not responsive to any change in a condition, and see the search notes thereto.
  
[List of Patents for class 137 subclass 109]    109Self-controlled branched flow systems:
 This subclass is indented under subclass 87.01.  Systems in which a single flow is divided into a plurality of flow paths or a plurality of flow paths are combined into a single flow path or in which a single flow path is divided and then recombined, and in which the flow in one branch or line is controlled in response to a change in a condition in another branch or line.
(1) Note. This and indented subclasses takes only those systems which include some significant branched structure such as having a valve and/or sensing means in a plurality of the branches or which require branched flow in order to be operative. For example, a pressure flow line having a mere relief valve or pressure relief passage mounted in the side is not classifiable as a branched system, because the outflow end of the line is not necessary for the operation of the pressure relief valve; such valves operate in the same manner when applied to a tank.
(2) Note. Plural relief valves opening into the atmosphere or the same tank or source are not branched flow systems, nor is a valve in which the flow is divided and recombined within the same valve body a branched flow system.

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455+,for relief and other condition responsive valves whether mounted in a flow line or in a container. (See (1) Note.)
561+,for branched flow distribution systems in which there is no control of a flow in response to a change in a sensed condition.
  
[List of Patents for class 137 subclass 110]    110Dividing and recombining:
 This subclass is indented under subclass 109.  Systems in which a single flow path is divided into a plurality of branch flow paths which are in turn recombined into a single flow path and in which at least one branch flow path is controlled in response to a sensing means which is at least partially affected by a condition in another branch flow path.

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89,for mixture condition maintaining or sensing systems involving dividing and recombining the flow.
115.01+,for by-pass or relief flows controlled by main line condition.
599.09,for systems dividing into parallel flow lines, having a fluid pressure-regulating valve, then recombining.
  
[List of Patents for class 137 subclass 111]    111Plural inflows:
 This subclass is indented under subclass 109.  Systems in which a plurality of flows from separate sources are joined, or are provided with a common outflow, and in which at least one flow path is controlled in response to a sensed condition change.

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88+,for system in which a plurality of fluids are mixed and the flow of at least one of the fluids is controlled in response to a change in a sensed condition of the mixture.
98+,for self-proportioning systems involving mutual control features in plural lines.
480,for combustion engine induction type governor valves controlling one or more auxiliary inlets, the main flow also being controlled in some instances.
602+,for branched flow distribution systems with multiple inlets and a single outlet in which there is no control of a flow in response to a change in a sensed condition.

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222Dispensing,   subclass 57 for control of a dispensed material by the weight, volume or pressure of a second dispensed material.
  
[List of Patents for class 137 subclass 112]    112Alternate or successive inflows:
 This subclass is indented under subclass 111.  Systems in which flow in one inlet is alternated with the flow in a second inlet or is substituted therefor in response to a sensing of a changed condition.
  
[List of Patents for class 137 subclass 113]    113Control by depletion of source:
 This subclass is indented under subclass 112.  Systems in which the control is in response to a failure or depletion of the source of the flow in one of the inflow.
(1) Note. Many of the patents in this subclass are drawn to bottled gas handling devices for substituting a second source of gas for the first when the pressure in the first drops below a satisfactory value.

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222Dispensing,   subclass 6 for gas or vapor dispensing of this type.
  
[List of Patents for class 137 subclass 114]    114One inflow supplements another:
 This subclass is indented under subclass 111.  Systems in which one inflow is added to or supplements the second flow and is in response to a sensed condition change such as reduction in pressure or flow in the second inflow or in the combined flow or in the level of accumulated fluid derived from the second or combined flow.

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98+,for self proportioning flow systems involving the uniting of a plurality of inflows with mutual control effects.
  
[List of Patents for class 137 subclass 115.01]    115.01Bypass or relief controlled by main line fluid condition:
 This subclass is indented under subclass 109.  Subject matter including a flow line with an inlet and outlet for a main flow and an outlet branch or bypass in which the flow is controlled in response to a variation in the fluid condition (e.g., fluid level, flow rate or pressure, or the like) in the main flow line detected by a sensor.

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223+,for inflatable article filling means having a back pressure cut-off or relief means.
455+,for relief and other condition responsive valves whether mounted in a flow line or container, in which there is no significantly claimed branched flow structure.
599.01through 601.21, for systems dividing into parallel flow lines then recombining.

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210Liquid Purification or Separation,   subclasses 96.1+ for a liquid purification or separation responsive to a variation of constituents in a liquid mixture.
  
[List of Patents for class 137 subclass 115.02]    115.02Liquid level responsive:
 This subclass is indented under subclass 115.01.  Subject matter wherein the sensor is detecting the variation in the levels of the liquid in the main line and in response thereto the sensor controls the flow in the bypass or relief.

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87.02,for a self-proportioning and correlating having a liquid level sensor.
101.25+,for a self-proportioning flow system having a liquid level sensor.
  
[List of Patents for class 137 subclass 115.03]    115.03Flow rate responsive:
 This subclass is indented under subclass 115.01.  Subject matter wherein the sensor is detecting the variation in the quantity of the fluid flowing in the main flow line in a set period of time and in response thereto the sensor controls the flow in the bypass or relief.
(1) Note. This subclass also includes a flow measurement by a pressure differential along the main line.

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87.03+,for a self-proportioning and correlating system having a flow rate sensor.
107,for supply and exhaust-type waste valves opening in response to the stoppage of the main line flow.
118.04+,for flow rate responsive plural outflows.
215+,for back flow prevention by vacuum breaking.
455+,for line condition responsive valves which respond to a change in the flow rate.
  
[List of Patents for class 137 subclass 115.04]    115.04Including controlling main line flow:
 This subclass is indented under subclass 115.03.  Subject matter wherein the sensor is regulating the flow in the main line in response to the variation in the flow rate.

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596.12,for supply and exhaust system with bypass.
  
[List of Patents for class 137 subclass 115.05]    115.05Relief or bypass closes as main opens:
 This subclass is indented under subclass 115.04.  Subject matter wherein the sensor, in response to the change in the flow rate, is simultaneously opening a main line valve and closing a relief valve in a branch line or vice versa.
  
[List of Patents for class 137 subclass 115.06]    115.06Bypass or relief valve biased open:
 This subclass is indented under subclass 115.03.  Subject matter comprising a valve means for permitting the flow to the bypass or relief valve is held open in absence of the flow by a flexibly adjustable device (e.g., a weight of the valve body itself, or a spring or such similar flexible means).

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115.16+,for pressure responsive biased open bypass or relief valve.
  
[List of Patents for class 137 subclass 115.07]    115.07Pilot valve operated:
 This subclass is indented under subclass 115.03.  Subject matter comprising an auxiliary valve control and wherein the bypass or relief valve is controlled by the auxiliary control valve in response to the variation of the flow rate in the main line.

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300,for a supplemental valve independent of a main valve for hydrant-type fluid handling.
  
[List of Patents for class 137 subclass 115.08]    115.08Carried choke:
 This subclass is indented under subclass 115.03.  Subject matter wherein the sensor is a fluid flow restricting element which is an integral part of the bypass or relief valve and the element is moving with the bypass or relief valve to restrict the flow.
  
[List of Patents for class 137 subclass 115.09]    115.09Choke:
 This subclass is indented under subclass 115.03.  Subject matter wherein the sensor includes a device for restricting the flow of the fluid in the main flow line.

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166Wells,   subclasses 316+ for changeable chokes.
  
[List of Patents for class 137 subclass 115.1]    115.1Variable choke resistance:
 This subclass is indented under subclass 115.09.  Subject matter wherein the choke is adjustable to provide different flow resistances without requiring disassembly of the sensor.
  
[List of Patents for class 137 subclass 115.11]    115.11Venturi:
 This subclass is indented under subclass 115.03.  Subject matter wherein the sensor includes a device which is a part of the main flow passage having a cross section of the part gradually constricted to a throat between two ends of the part and gradually expanded from the throat to the cross section of the passage.
(1) Note. The device is used with a pressure tap at the throat and another pressure tap at the normal flow passage to register the pressure differential at the throat relative to a pressure in the normal passage and signals the sensor which in turn exercises the control of the flow in the bypass or relief.
  
[List of Patents for class 137 subclass 115.12]    115.12Flapper:
 This subclass is indented under subclass 115.03.  Subject matter wherein the sensor includes a member supported at one end and moving by the momentum of the fluid in the flow line to operate the bypass or relief valve.
  
[List of Patents for class 137 subclass 115.13]    115.13Pressure responsive:
 This subclass is indented under subclass 115.01.  Subject matter wherein the sensor is detecting the pressure of the fluid in the main flow line and in response thereto controls the bypass or relief valve.

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118.06+,and 119.08+, for self-controlled pressure responsive plural outflows and pressure responsive alternate and substituted plural outflows respectively.
  
[List of Patents for class 137 subclass 115.14]    115.14Common sensor for both bypass or relief valve and other branch valve:
 This subclass is indented under subclass 115.13.  Subject matter comprising an additional valve in another flow path and wherein the sensor which controls the bypass or relief valve also controls the additional valve.

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488+,for fluid pressure-type pilot valves.
  
[List of Patents for class 137 subclass 115.15]    115.15Bypass or relief valve opens as other branch valve closes.
 This subclass is indented under subclass 115.14.  Subject matter wherein the sensor opens the bypass or relief valve in the main line while it closes the additional valve in the main line or vice versa.
  
[List of Patents for class 137 subclass 115.16]    115.16Bypass or relief valve biased open:
 This subclass is indented under subclass 115.13.  Subject matter wherein the bypass or relief passage is held open in absence of the fluid pressure by a flexibly adjustable device (e.g., a weight of the valve body itself, or a spring, or such similar flexible means).

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115.06,for flow rate responsive biased open bypass or relief valve.
  
[List of Patents for class 137 subclass 115.17]    115.17Increasing pressure progressively closes then reopens bypass or relief valve:
 This subclass is indented under subclass 115.16.  Subject matter wherein the increase in the fluid pressure progressively closes the bypass or relief valve and reopens at still higher pressure.
  
[List of Patents for class 137 subclass 115.18]    115.18Bypass or relief valve responsive to pressure downstream of outlet valve:
 This subclass is indented under subclass 115.13.  Subject matter wherein the outlet branch includes a valve which is located before the bypass or relief valve and the bypass or relief valve is controlled by the fluid pressure between the outlet valve and the bypass or relief valve.
  
[List of Patents for class 137 subclass 115.19]    115.19Pilot valve:
 This subclass is indented under subclass 115.18.  Subject matter comprising an auxiliary control valve and wherein the bypass or relief valve is controlled by the auxiliary control valve in response to the pressure in the main flow line.

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488+,for a fluid pressure-type pilot control.
  
[List of Patents for class 137 subclass 115.2]    115.2Outlet valve carried by bypass or relief valve:
 This subclass is indented under subclass 115.18.  Subject matter wherein the outlet valve is an integral part of the bypass or relief valve and the outlet valve moves with the bypass or relief valve.
(1) Note. The outlet valve in this subclass is located between the pressure sensor and the bypass or relief valve.
  
[List of Patents for class 137 subclass 115.21]    115.21Plural sensors for single bypass or relief valve:
 This subclass is indented under subclass 115.13.  Subject matter comprising at least two pressure sensors for controlling either the bypass or relief valve.

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115.03+,for a flow responsive bypass or relief valve.
  
[List of Patents for class 137 subclass 115.22]    115.22Sensors interconnected by timing or restrictive orifice:
 This subclass is indented under subclass 115.21.  Subject matter wherein the pressure sensors are connected to each other directly by means of a restrictive passage in order that all the sensors react to the same pressure, but with a different speed of response.

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192Clutches and Power-Stop Control,   subclasses 109+ for fluid retarders.
  
[List of Patents for class 137 subclass 115.23]    115.23Pilot valve operated:
 This subclass is indented under subclass 115.13.  Subject matter comprising an auxiliary control valve and wherein the bypass or relief valve is controlled by the auxiliary control valve in response to the pressure in the main flow line.

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115.07,for a pilot valve responsive to a fluid flow rate.
  
[List of Patents for class 137 subclass 115.24]    115.24Mechanical movement between sensor and valve:
 This subclass is indented under subclass 115.13.  Subject matter wherein the sensor and the bypass or relief valve are so interconnected that the sensor is moving at a different rate and in different direction than the movement of the bypass or relief.
  
[List of Patents for class 137 subclass 115.25]    115.25Electrical control:
 This subclass is indented under subclass 115.13.  Subject matter comprising an electrical element and wherein the sensor controls the bypass or relief by means of the electrical element.
  
[List of Patents for class 137 subclass 115.26]    115.26Sensor rigid with valve:
 This subclass is indented under subclass 115.13.  Subject matter wherein the sensor is either (a) assembled as an integral part of the bypass or relief valve, or (b) attached inflexibly to the bypass or relief valve.
  
[List of Patents for class 137 subclass 115.27]    115.27Flexible sensor:
 This subclass is indented under subclass 115.26.  Subject matter wherein the sensor is constructed of a thin pliable or resilient material such as used in a diaphragm or bellows or the like.
  
[List of Patents for class 137 subclass 115.28]    115.28Pressure responsive outlet valve:
 This subclass is indented under subclass 115.26.  Subject matter comprising a valve on the outlet branch and wherein the valve is responsive to a pressure being sensed in the outlet branch.
  
[List of Patents for class 137 subclass 116.3]    116.3With pressure reducing inlet valve:
 This subclass is indented under subclass 115.  Devices with a correlated fluid pressure responsive regulator or pressure reducing valve controlling the inlet branch.

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505.11,for pressure regulators with independently operable relief valves.
  
[List of Patents for class 137 subclass 116.5]    116.5Relief port through common sensing means:
 This subclass is indented under subclass 116.3.  Devices in which a common sensing means for both inlet control and relief control has a valve controlled outlet or relief passage.
  
[List of Patents for class 137 subclass 118.01]    118.01Plural outflows:
 This subclass is indented under subclass 109.  Subject matter comprising a sensor and wherein the flow is from a single source and is divided in to a plurality of paths which the flow may take to separate destinations and the flow is controlled by the sensor in response to the change in the condition (e.g., fluid level, flow rate, or pressure, or the like), or a characteristic of the fluid.

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98+,for plural flow systems with mutual control devices.
115.01+,for branch flow systems in which a bypass is controlled in response to a change in condition.
455+,for pressure relief valve which may be mounted on the side of the flow line in which there is no branched flow characteristics claimed.
861+,for nonautomatic distribution systems having a plurality of controlled outflows.
  
[List of Patents for class 137 subclass 118.02]    118.02Single actuator operates plural outlets simultaneously:
 This subclass is indented under subclass 118.01.  Subject matter comprising an outlet valve in each outflow and wherein the outlet valves are opened or closed at the same time by only one sensor.

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625+,for noncorrelated multiway valves.
862+,for plural outlet valves controlled by a single operator without correlation control.
  
[List of Patents for class 137 subclass 118.03]    118.03Biased open isolation valve:
 This subclass is indented under subclass 118.01.  Subject matter comprising an outlet valve in each outflow and wherein each outlet valve is held open in the absence of a fluid pressure by a flexibly adjustable device (e.g., a weight of the valve body itself, or a spring) and at least one valve closes in response to a sudden pressure drop or flow increase in the outlet line.

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458,through 466, for valves on a single line (one inlet and one outlet) serving the same purpose, but requiring reset.
498,and 517+, for valves on a single line that are biased open and shut when the downstream line has a sudden pressure drop.

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303Fluid-Pressure Brake and Analogous Brake Systems,   subclass 84.2 for a flow retarding isolation valves.
  
[List of Patents for class 137 subclass 118.04]    118.04Flow rate responsive:
 This subclass is indented under subclass 118.01.  Subject matter wherein the sensor is detecting a change in the quantity of the fluid flowing in the main line in a set period of time and in response thereto controls the outflows.

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115.03+,for bypass or relief controlled by the flow rate in self-controlled branch flow system.
  
[List of Patents for class 137 subclass 118.05]    118.05Primer valve:
 This subclass is indented under subclass 118.04.  Subject matter wherein the change in the fluid flow rate in the main line actuates an outlet leading to a liquid trap seal.

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247+,for liquid trap seals or liquid valves.
  
[List of Patents for class 137 subclass 118.06]    118.06Pressure responsive:
 This subclass is indented under subclass 118.01.  Subject matter wherein the sensor detects a change in the fluid pressure in the main line and in response thereto controls the outflows.

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115.13+,for a similar device controlling a bypass or relief valve.
119.08+,for self-controlled pressure responsive alternately or successively substituted plural outflows.
  
[List of Patents for class 137 subclass 118.07]    118.07With external control for correlating valve (e.g., manual):
 This subclass is indented under subclass 118.06.  Subject matter wherein, in addition to the pressure responsive sensor, the outflows are controlled by a device independent of the condition of the flow line.
(1) Note. Modifiers which merely vary the loading are not deemed to constitute external control means within this definition.

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481,for suction controlled valves which are manually modified or adjusted.
522+,for direct response valves in combination with external means for opposing the closing bias.
613+,for system comprising plural valves arranged in series in the flowline wherein manual or external means operate one valve to produce a change in the condition in the flowline in order to utilize such changed condition to effect automatic operation of the other valve in the flowline.
  
[List of Patents for class 137 subclass 119.01]    119.01Alternately or successively substituted outflow:
 This subclass is indented under subclass 118.01.  Subject matter wherein (a) the fluid is flowing first through one outlet and then changed to another outlet, or (b) more than two outlets are substituted for each other in sequence; in response to the change in the condition or characteristic of the main line flow detected by the sensor.

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160+,for plural feed traps alternately filled and alternately discharged by gas pressure.
625+,for multiway valve unit actuation which is not responsive to a change in condition.
  
[List of Patents for class 137 subclass 119.02]    119.02Four port reversing valve:
 This subclass is indented under subclass 119.01.  Subject matter including a four way valve having an inlet port, an outlet port and two intermediate ports, the valve being selectively movable into two positions, in one position the inlet port being connected to the first intermediate port and the second intermediate port being connected to the outlet port, and in the other position the inlet port being connected to the second intermediate port and the first intermediate port being connected to the outlet port.

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309+,for reversing valves in connection with a regenerative type of furnace.
625.43,for four port reversing valve not of the correlating type.
  
[List of Patents for class 137 subclass 119.03]    119.03Responsive to pressure or flow interruption:
 This subclass is indented under subclass 119.01.  Subject matter comprising a valve and wherein the alternately or successively substituted outflow is controlled by the valve in response to a break in the pressure of the fluid or a break in the flow of the fluid being detected by the sensor.
  
[List of Patents for class 137 subclass 119.04]    119.04Plural outlets control with automatic reset:
 This subclass is indented under subclass 119.03.  Subject matter wherein the valve is regulating more than one outlet; said valve opens one outlet in response to the pressure or flow interruption and closes that outlet and opens another outlet when the pressure or flow is restored.
(1) Note. The valves in this subclass are diverter valves that operate, for example, when a valve in a rinse sprayer is manually opened.
  
[List of Patents for class 137 subclass 119.05]    119.05Manually set to a single outflow position:
 This subclass is indented under subclass 119.03.  Subject matter wherein the sensor causes the valve to move from a first position to a second position to open or close one outlet, but the valve is moved back to the first position by an application of a force exerted by a living being.
  
[List of Patents for class 137 subclass 119.06]    119.06Flow rate responsive:
 This subclass is indented under subclass 119.01.  Subject matter wherein the alternately or successively substituted outflow is responsive to a change in the amount of fluid flowing in the flow line in a set period of time being detected by the sensor.

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87.03+,for a flow rate responsive bypass or relief.
118.04+,for flow rate responsive plural outflows.
  
[List of Patents for class 137 subclass 119.07]    119.07Flow sensing turbine:
 This subclass is indented under subclass 119.06.  Subject matter wherein the sensor comprising a member pivoted for oscillation or rotation, and having blades, vanes or surfaces which are exposed to the flow and rotating or tending to rotate the member.
  
[List of Patents for class 137 subclass 119.08]    119.08Pressure responsive:
 This subclass is indented under subclass 119.01.  Subject matter wherein the change in the condition is a fluid pressure detected by the sensor for controlling the alternately or successively substituted outflow of the fluid in the main flow line.

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87.04,for a pressure differential sensor controlling the flow.
118.06+,for pressure responsive plural outflows.
  
[List of Patents for class 137 subclass 119.09]    119.09Responsive to outlet pressure:
 This subclass is indented under subclass 119.08.  Subject matter wherein in response to the change in the fluid pressure in the outlet branch the sensor controls the outflow of the fluid.
  
[List of Patents for class 137 subclass 119.1]    119.1Electrical control:
 This subclass is indented under subclass 119.01.  Subject matter comprising an electrical element and wherein the sensor controls the outlet by means of the electrical element.

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596.16,for an electric pilot-actuated supply and exhaust system.
  
[List of Patents for class 137 subclass 120]    120Control by filling auxiliary gravitating or float operating tank:
 This subclass is indented under subclass 119.01.  Systems in which the control of the flow is in response to a filling of a separate or auxiliary tank of the gravitating or float operating type.
(1) Note. Many of the patents in this subclass are drawn to rain spouts in which the initial flow is wasted to remove dirt before the rain water is fed to the cistern or storage vessel.

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386+,for other liquid level responsive flow control, especially subclass 408 for gravitating tank devices and subclasses 409+ for float operated valves, and see the search notes to subclasses 386, 403, 408, and 409.
  
[List of Patents for class 137 subclass 121]    121Control by filling outlet tank or receiver:
 This subclass is indented under subclass 119.01.  Systems in which the control of the flow is in response to a filling of a tank or receivers receiving fluid from an outflow of the system.

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115.01+,for by-pass control in response to a change in main line condition.
386+,for other liquid level responsive flow control.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclasses 198+ for filling devices controlled by the quantity in a separable receiver.
222Dispensing,   subclass 56 for delivery from a dispenser controlled by the quantity in a discharging receiver.
  
[List of Patents for class 137 subclass 122]    122Float controlled:
 This subclass is indented under subclass 121.  Systems in which the filling of the tank or receiver is sensed by means of a float.

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386+,particularly subclasses 397, 398+ and 409+ for other flow control responsive to a float, and see the search notes to subclass 409.
  
[List of Patents for class 137 subclass 123]    123SIPHONS:
 This subclass is indented under the class definition.  Apparatus having a flow passage comprising two branches or legs of unequal effective length by which a liquid can be transferred to a lower level over an intermediate elevation by the pressure of the atmosphere in forcing the liquid up the shorter branch or leg immersed in it while the excess of weight of the liquid in the longer branch (when once filled) causes a continuous flow.
(1) Note. This group of subclasses is directed to the siphon subcombination, i.e., the siphon element, per se, and this element associated with supply and/or receiver chambers and/or such other adjuncts as are commonly found in this class combined with the basic subject matter of the class. Patents for combinations of siphons with other art devices are classified with the art device.

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591,for tanks with internally extending inverted U passage, which are not intended to operate as siphons even though of the proper design for it.

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4Baths, Closets, Sinks, and Spittoons,   subclasses 368+ for water closet flushing tanks having an outlet siphon and subclasses 421+ for siphon bowls.
141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclass 230 for siphon tube filling of separable receivers, and see the search notes thereto.
222Dispensing,   subclass 204 for dispenser type siphons with external starting means and subclass 416 for dispensing siphons, per se.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotographic device.
  
[List of Patents for class 137 subclass 124]    124Plural:
 This subclass is indented under subclass 123.  Apparatus including a plurality of siphons.
  
[List of Patents for class 137 subclass 125]    125Tank truck mounted:
 This subclass is indented under subclass 124.  Apparatus in which the siphons are connected to the compartments of a tank truck to discharge the liquid contained therein.

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267,for tank trucks having a plurality of compartments with manifold or grouped outlets arranged for parallel flow.
899+,for vehicle supported fluent material handling systems, and see the search notes to subclasses 351 and 899.
  
[List of Patents for class 137 subclass 126]    126Sequentially discharging in parallel:
 This subclass is indented under subclass 124.  Apparatus in which the plural siphons operate successively to produce plural discharges from the same or from different supply chambers. Means are usually provided whereby the termination of the discharge of one of the siphons initiates the discharge of a subsequently operated siphon.

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627,627.5 and 628+, for sequentially actuated valves, and see the search notes thereto.
  
[List of Patents for class 137 subclass 127]    127From plural tanks:
 This subclass is indented under subclass 126.  Apparatus in which at least some of the siphons are supplied from different chambers.

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256+,for sequentially filled and emptied plural tanks in parallel relation.
  
[List of Patents for class 137 subclass 128]    128Main siphon with auxiliary starting, stopping or resetting siphon:
 This subclass is indented under subclass 124.  Apparatus having a main siphon through which the major portion of the fluid is discharged and an auxiliary siphon which operates to start or stop fluid flow through the main siphon, or, after discharge of the main siphon, restores some or all of the main siphon operating means to a position permitting a subsequent discharge.
(1) Note. In series arrangements of plural tanks and siphons wherein one siphon discharges into a tank which is emptied by a second siphon, the first siphon is not regarded as a starter for the second when discharge of the second siphon results merely upon accumulation of sufficient fluid in the tank to permit such discharge, and patents for this subject matter are not included in this or the indented subclass.

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132+,for periodic siphons, or those which discharge as often as a supply sufficient for starting is accumulated.
142+,for other siphon starting means.
  
[List of Patents for class 137 subclass 129]    129Sinking or bucket-type float operated main siphon, float emptying auxiliary siphon:
 This subclass is indented under subclass 128.  Apparatus having a float which fills with liquid and sinks to initiate discharge through the main siphon, the auxiliary siphon then emptying the float.

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404,for liquid level responsive control means comprising a sinking or bucket type float, and see the search notes thereto.
427,for float controlled valves with float leakage disposal.
  
[List of Patents for class 137 subclass 130]    130With discharge-controlling receiver:
 This subclass is indented under subclass 123.  Apparatus having a receiver for the discharge of the siphon, the siphon discharge being controlled by a condition in the receiver.

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121,for self correlating systems controlled by a filled receiver.
453+,for liquid level maintaining systems including barometric control.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclass 230 for siphon tube filling of separable receivers, and see the search notes thereto.
222Dispensing,   subclass 56 for automatic control of dispensing by the quantity in a receiver which is also discharging.
  
[List of Patents for class 137 subclass 131]    131With float:
 This subclass is indented under subclass 130.  Apparatus in which a float responsive to a condition in the receiver controls discharge of the siphon.

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135+,for siphon discharge controlled by float means responsive to liquid accumulation in the system.
409+,for float operated valves of general utility, and see the search notes to subclass 409.
  
[List of Patents for class 137 subclass 132]    132Periodic or accumulation responsive discharge:
 This subclass is indented under subclass 123.  Apparatus having means responsive to a condition or characteristic of the fluid in the system whereby the siphon is caused to discharge at recurrent intervals, i.e., as often as a certain level of tank contents is reached.

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130+,for apparatus in which siphon discharge is controlled by a condition in a receptacle into which the siphon discharges.
396+,for self-emptying tanks of other types which empty in response to liquid level as often as filled, and see the search notes to subclass 396.

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73Measuring and Testing,   subclasses 222 and 226 for tank type meters with siphon discharge.
  
[List of Patents for class 137 subclass 133]    133With manual control:
 This subclass is indented under subclass 132.  Apparatus having means whereby the siphon may be discharged either by manual operation or by a condition or characteristic of the fluid in the system, the manual control being either auxiliary to the automatic or the control being convertible from one type to the other.
(1) Note. See the class definition, section 3 for search notes on combined automatic and nonautomatic controls in this and related classes.

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269+,for convertible fluid handling systems.
  
[List of Patents for class 137 subclass 134]    134Control by filling auxiliary tank:
 This subclass is indented under subclass 132.  Apparatus having an additional accumulation receptacle arranged to discharge recurrently into the siphon chamber, such recurrent discharge initiating discharge of the siphon.

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142+,for other siphon starting means.
  
[List of Patents for class 137 subclass 135]    135Float-operated inlet to siphon:
 This subclass is indented under subclass 132.  Apparatus having a float responsive to the accumulation of liquid in the siphon chamber in which the float actuates means for admitting liquid to the siphon element to initiate liquid flow there through.

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409+,for float controlled valves of general utility, and see the search notes to subclass 409.
  
[List of Patents for class 137 subclass 136]    136Release of trapped air:
 This subclass is indented under subclass 132.  Apparatus in which the liquid accumulating in the siphon chamber traps air in the siphon element and means is provided to release such trapped air to initiate liquid flow through the siphon.

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143,for siphon venting or breaking.
144,for removal of the air which accumulates in siphons during use.

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4Baths, Closets, Sinks, and Spittoons,   subclasses 369+ for water closet flush tanks having an outlet siphon which is prevented from discharging until air is positively release therefrom.
  
[List of Patents for class 137 subclass 137]    137Through float-operated vent:
 This subclass is indented under subclass 136.  Apparatus in which the trapped air releasing means is actuated by a float responsive to accumulation of liquid in the siphon system.

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202,and 213+, for liquid level responsive vents for gas in diverse fluid containing pressure systems.
409+,for float operated valves of general utility and see the search notes to subclass 409.
583+,for distribution systems having a gas vent and other flow passages, and see the search notes to subclasses 583 and 587.

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222Dispensing,   subclass 69 for float operated vents in dispensers.
  
[List of Patents for class 137 subclass 138]    138Through liquid trap seal:
 This subclass is indented under subclass 136.  Apparatus in which the trapped air releasing means comprises a liquid trap seal, which may be formed by suitable configuration of the discharge end of the siphon element.

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247+,for combinations of liquid trap seals with fluid distribution apparatus other than siphons, and see the search notes to subclass 247.
  
[List of Patents for class 137 subclass 139]    139Auxiliary liquid trap seal:
 This subclass is indented under subclass 138.  Apparatus in which the air releasing seal comprises a second liquid trap seal in addition to the air trapping seal necessarily present at the discharge end of the siphon element.
  
[List of Patents for class 137 subclass 140]    140With strainer, filter, separator or sediment trap:
 This subclass is indented under subclass 123.  Apparatus combined with a strainer, filter, separator or sediment trap.

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544+,for other fluid distribution apparatus combined with means for separating solid material from the fluid, and see the search notes to subclass 544.

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210Liquid Purification or Separation,   subclasses 416.1+ for filter means of that class (210) combined with means providing a suction.
  
[List of Patents for class 137 subclass 141]    141With recorder, register, signal, indicator or inspection window:
 This subclass is indented under subclass 123.  Apparatus combined with a recorder, register, signal, indicator or inspection window.

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551+,for other fluid distribution apparatus combined with the listed devices, and see the search notes to subclass 551.
  
[List of Patents for class 137 subclass 142]    142With flow starting, stopping or maintaining means:
 This subclass is indented under subclass 123.  Apparatus having means for applying pressure to initiate, stop or maintain liquid flow, to vent air for starting, stopping or maintaining siphon flow, or for controlling the flow by opening, closing or variably restricting the main flow path of the siphon.

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128+,for siphons with auxiliary starting siphon.
130+,for siphon discharge controlled by the receiver.
132+,for periodic discharging or level responsive siphons.

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222Dispensing,   subclass 204 for dispenser siphons with auxiliary starting means and subclass 416 for dispenser siphons.
  
[List of Patents for class 137 subclass 143]    143Siphon venting or breaking:
 This subclass is indented under subclass 142.  Apparatus in which the siphon is provided with means for stopping or regulating the flow through the siphon by admitting air into the siphon.

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151,for apparatus including siphons having a valve or closure for controlling the flow of liquid therethrough.
215+,for apparatus for preventing reverse flow siphoning action in apparatus not normally operating by siphon action.
583+,for distributing systems including a gas vent and at least one other flow opening, and see the search notes to subclasses 583 and 587.
  
[List of Patents for class 137 subclass 144]    144With leakage or entrained air removal:
 This subclass is indented under subclass 142.  Apparatus having means for removing air which accumulates in the siphon while it is discharging liquid, such means comprising a positively acting eductor connected at one or more high points of a siphon and having either a separate or a line jet operated pumping means.

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136+,for release of trapped air to start a siphon of the periodic type.
143,for siphon venting means which operate to reduce or stop the flow in the siphon.
  
[List of Patents for class 137 subclass 145]    145Pressure applied to liquid in supply chamber:
 This subclass is indented under subclass 142.  Apparatus in which pressure either of liquid or a displacing gas is developed in that part of the system which holds the material into which the inlet end of the siphon dips to fill the siphon and start the flow.

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130,for siphons started by controlling the position or pressure condition of the receiver.
206+,for gas pressure displacement of a liquid, and see the search notes to subclass 206.
565+,for distribution systems having a pump as part thereof, and see the search notes to subclass 565.

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4Baths, Closets, Sinks, and Spittoons,   subclass 375 for water displacer starters for siphons in water closet tanks.
222Dispensing,   subclass 204 for siphons combined with discharge assistants in dispensers.
  
[List of Patents for class 137 subclass 146]    146Plunge or immersion starting:
 This subclass is indented under subclass 142.  Apparatus in which a movable siphon is provided with an enlarged entrance chamber whereby when the chamber end is rapidly introduced into the supply a surge of fluid through the line results, which fills the siphon and initiates flow.
  
[List of Patents for class 137 subclass 147]    147Pump or liquid displacement device for flow passage:
 This subclass is indented under subclass 142.  Apparatus in which the means comprises a pump mounted in or on the siphon.

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565+,for distribution systems with pumps, and see the search notes to subclass 565.

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4Baths, Closets, Sinks, and Spittoons,   subclasses 42+ for siphon starters for water closet tanks.
222Dispensing,   subclass 204 for siphons with pump or other discharge assistant type starter.
  
[List of Patents for class 137 subclass 148]    148Piston:
 This subclass is indented under subclass 147.  Apparatus in which the pump includes a piston.

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4Baths, Closets, Sinks, and Spittoons,   subclass 373 for water closet flushing tanks having a siphon outlet which is started by a piston or its equivalent.
  
[List of Patents for class 137 subclass 149]    149Co-axial within flow passage:
 This subclass is indented under subclass 148.  Apparatus in which the piston is moved in the flow passage of the siphon.
  
[List of Patents for class 137 subclass 150]    150Collapsible bulb:
 This subclass is indented under subclass 147.  Apparatus in which the pump comprises a collapsible bulb.

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222Dispensing,   subclass 209 for collapsible bulb fluid pressure generators in dispensers.
  
[List of Patents for class 137 subclass 150.5]    150.5Siphon inlet movable to and from seat:
 This subclass is indented under subclass 142.  Apparatus in which the siphon is movably mounted so that the inlet end comes into contact with the supply chamber wall when flow is cut off, the contact either operating a valve or directly blocking flow through the siphon.
  
[List of Patents for class 137 subclass 151]    151With valve or closure in-flow passage:
 This subclass is indented under subclass 142.  Apparatus having a flow controlling stopping means which comprises a valve or closure.

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131,for float-operated valves in receivers controlling the discharge of siphons.
135,for float-operated valves for inlets to siphons of the level responsive type.
  
[List of Patents for class 137 subclass 152]    152With means for mounting and/or positioning relative to siphon chamber:
 This subclass is indented under subclass 123.  Apparatus in which the siphon is provided with means for mounting and/or positioning it relative to the chamber from which liquid is supplied to the siphon.

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222Dispensing,   subclass 416 for dispensing siphons, per se.
  
[List of Patents for class 137 subclass 153]    153Elements:
 This subclass is indented under subclass 123.  Apparatus comprising the siphon passage forming means, per se.

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222Dispensing,   subclass 416 for dispenser siphons, per se.
  
[List of Patents for class 137 subclass 154]    154DIVERSE FLUID CONTAINING PRESSURE SYSTEMS:
 This subclass is indented under the class definition.  Apparatus which contain under pressure a plurality of fluids having diverse characteristics such as fluid phase (i.e., gas and liquid) or specific gravity, and which fluids are in contact in at least a part of the system.
(1) Note. The pressure need not exist continuously in the system, but must be present at least some of the time.
(2) Note. This subclass does not include systems in which diverse fluids as steam and water are utilized merely for heating purposes.

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241,for steam sterilization in fluid handling systems.
246,for liquid supplied at a valve interface, which liquid may be different from the fluid handled in the system.
334+,for gas and liquid containing systems for heating, as by mixing steam and water. See Note (1) above.

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222Dispensing,   subclasses 394+ for dispensers with fluid pressure discharge assistants, and see the search notes to subclass 394.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 155]    155Gas lift valves for wells:
 This subclass is indented under subclass 154.  Apparatus which controls a gas to be injected or introduced into the liquid column of well to elevate the liquid.

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417Pumps,   subclass 109 for aerated column type pumps combined with valve means for a controlling a gas inlet.
  
[List of Patents for class 137 subclass 156]    156Gas pressure discharge of liquids feed traps (e.g., to boiler):
 This subclass is indented under subclass 154.  Apparatus which includes a receiving chamber which holds a liquid for subsequent discharge to a receiver at a higher pressure, which discharge is controlled or enabled by the controlled application of a gas pressure over the liquid equal to or greater than the pressure to which the liquid is discharged.
(1) Note. The discharge may be to a closed receiver at higher pressure than the trap filling pressure, which may be at atmospheric pressure, or the discharge may be to atmosphere or an open receiver from a vacuum system.
(2) Note. A feed or discharge trap in the fluid handling art is an auxiliary chamber which collects or portions out a separated quantity of fluid which is to be added to or removed from the quantity in the container to which it is auxiliary. It may discharge the separated quantity or merely make it accessible.

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177+,for gas traps which may utilize internal uncontrolled pressure for liquid discharge.
206+,for gas pressure discharge of non feed trap type containers.
571+,for plural tanks or compartments connected for serial flow, and see the search notes to subclass 571.

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122Liquid Heaters and Vaporizers,   subclasses 451+ for feed-traps of particular application to boilers.
417Pumps,   subclasses 118+ for liquid pumping by supplying or exhausting gaseous motive fluid to or from a liquid pumping chamber.
  
[List of Patents for class 137 subclass 157]    157Gas pressure controlled by amount of liquids in boiler or discharge receiver:
 This subclass is indented under subclass 156.  Feed-traps wherein the application of gas pressure is controlled by the amount of liquid in the discharge receiving receptacle, as the boiler.

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130+,for siphon discharge controlled by the receiver.
205,for liquid filling by evacuating a container and see the search notes thereto.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclasses 39+ for diverse fluid containing pressure filling systems wherein the filling means is controlled by the gas condition in the receiver.
222Dispensing,   subclass 56 for automatic dispensing controlled by the quantity in a discharging receiver.
  
[List of Patents for class 137 subclass 158]    158Pressure connection at liquid level in boiler or discharge receiver:
 This subclass is indented under subclass 157.  Feed-traps which include a gas pressure connection at the desired liquid level in the discharging receiver.

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393,for level controlled valves having a control fluid connection at the desired liquid level in nonpressure systems.
  
[List of Patents for class 137 subclass 159]    159Gas pressure controlled by amount of liquid in trap:
 This subclass is indented under subclass 156.  Feed-traps wherein the application of gas pressure is controlled by the amount of liquid in the feed-trap chamber.

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183+,and 199+, for fluid responsive valves in fluid separating traps in diverse fluid containing pressure systems.
  
[List of Patents for class 137 subclass 160]    160Plural trap chambers:
 This subclass is indented under subclass 159.  Feed-traps which include a plurality of trap chambers.
(1) Note. The plural trap chambers may be arranged serially or in parallel, as for alternating use.
  
[List of Patents for class 137 subclass 161]    161Gravitating:
 This subclass is indented under subclass 160.  Feed-traps wherein alternately acting feed traps are moved by gravity to discharge their contents and the lowering of one trap raises the other trap.

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403+,for liquid level responsive or maintaining control systems operated by the weight of accumulated fluid, especially subclass 408 for accumulation in the gravitating tank, and see the search notes to subclasses 403 and 408.

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177Weighing Scales,   subclass 90 for weighing apparatus in which alternating weight chambers control flow of the material being weighed.
  
[List of Patents for class 137 subclass 162]    162Gravitating vessel:
 This subclass is indented under subclass 159.  Feed-traps wherein liquid accumulates in a vessel which lowers by gravity upon the accumulation of a predetermined amount of liquid therein to control the admission of gas pressure.

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189+,for separating traps of the gravitating type in diverse fluid containing pressure systems.
408,for liquid level responsive devices of the gravitating tank type, and see the search notes thereto.
  
[List of Patents for class 137 subclass 163]    163Sinking or bucket type float:
 This subclass is indented under subclass 162.  Feed-traps wherein the vessel is an open-topped float which floats in liquid and sinks when filled with liquid.

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404,for sinking floats in liquid level responsive or maintaining systems, and see the search notes thereto.
  
[List of Patents for class 137 subclass 164]    164Pivoted vessel with fluid passage through pivot:
 This subclass is indented under subclass 162.  Feed-traps wherein the vessel is pivoted and a fluid passage is provided through the pivot.
  
[List of Patents for class 137 subclass 165]    165Float responsive:
 This subclass is indented under subclass 159.  Feed-traps wherein the gas pressure application is controlled by a float in the feed-trap chamber.

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192+,and 202, for float responsive fluid separating traps and vents in diverse fluid containing pressure systems.
409+,for float operated valves of general utility, and see the search notes to subclass 409.
  
[List of Patents for class 137 subclass 166]    166Liquid control valve positively actuated:
 This subclass is indented under subclass 165.  Feed-traps wherein a valve in the liquid flow line to or from the trap is actuated by a distinct positively acting mechanism in conjunction with the float control of the gas inlet.
(1) Note. Self actuating valves such as check valves are not "positively" actuated.
(2) Note. See the class definition, section 3 for search notes on automatic valves combined with other actuating means.
  
[List of Patents for class 137 subclass 167]    167Gas condensing type:
 This subclass is indented under subclass 165.  Feed-traps which are not provided with a gas outlet, as the gas applied to discharge the trap is in the form of a readily condensed vapor such as steam which condenses to eliminate the gas pressure after discharge to allow subsequent filling of the trap.
  
[List of Patents for class 137 subclass 168]    168Gas inlet and outlet valves unitary:
 This subclass is indented under subclass 165.  Feed-traps provided with gas inlet and outlet valves which are integrally mounted on a single actuating stem.
(1) Note. See the class definition, section 4 for search notes on plural valves in the fluid handling systems of this and related classes.

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411,for liquid level responsive or maintaining systems in which plural valves are controlled by one float.
  
[List of Patents for class 137 subclass 169]    169Gas pressure controlled by manual or cyclic means:
 This subclass is indented under subclass 156.  Feed-traps wherein the gas pressure application to the feed-traps controlled by manual or cyclic means.

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631+,for cyclic actuation of valves, and see the search notes to subclass 631.
  
[List of Patents for class 137 subclass 170]    170Movable trap chamber:
 This subclass is indented under subclass 169.  Feed traps wherein the feed trap is moved into discharge relationship with the receiver for discharge and the controlling gas pressure is the pressure in the discharge receiver which may enable discharge of the liquid by the mere flow connection of the trap chamber to the receiver.

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222Dispensing,   subclass 636 for fluid flow discharge from a movable trap chamber and subclasses 344+ for dispensers with movable trap chambers.
406Conveyors: Fluid Current,   subclasses 63+ for material intake into a fluid current conveyor and comprising successively registering pockets.
  
[List of Patents for class 137 subclass 170.1]    170.1Foam control in gas charged liquids:
 This subclass is indented under subclass 154.  Apparatus in which the fluids comprise a liquid and a gas which has been intentionally and desirably entrained in the liquid to form a mixture which is subject to frothing under certain conditions and having means for preserving or modifying the pressure of gas in the mixture, thereby controlling the amount of froth released, retained or formed in the handling of the mixture.
(1) Note. Disclosures of froth or foam control functions for structures of general utility in the fluid handling arts does not result in classification in this or the indented subclasses unless there is a claimed disclosure of a combination of handling features which specialize the overall apparatus to a foam controlling function and for which no suitable general classification exists elsewhere.

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12.5,for methods of controlling foam in handling carbonated liquids.
206+,for gas pressure storage over or displacement of liquids in diverse fluid containing pressure systems, and see the search notes thereto.

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516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclasses 115+ for processes of or compositions for or subcombination compositions for the breaking of or inhibiting of foam colloid systems, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 137 subclass 170.2]    170.2Level or pressure responsive:
 This subclass is indented under subclass 170.1.  Apparatus having means for sensing a force exerted by the mixture or of either of its component parts, or means for sensing a fluid level, such means causing operation of a control device.

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386+,for liquid level responsive or maintaining systems of general application.

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516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclasses 115+ for processes of or compositions for or subcombination compositions for the breaking of or inhibiting of foam colloid systems, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 137 subclass 170.3]    170.3Separate handling of foam:
 This subclass is indented under subclass 170.1.  Apparatus having means apart from the mixture handling means for treating or disposing of the froth while it remains in the frothy state either by discharging said froth, by extracting liquid from it, or by storing or retaining it in a separate chamber.
(1) Note. Structures involving foam control within the meaning of subclass 170.1 have been placed in this subclass where the claimed structure includes a passageway for the discharge of foam on the basis of the applicant"s disclosure that foam is so discharged rather than gas.

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170.4+,for similar structures where only liberated gas is separately handled.

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96Gas Separation: Apparatus,   subclasses 155+ for degasifying means for liquid, per se.
516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclasses 115+ for processes of or compositions for or subcombination compositions for the breaking of or inhibiting of foam colloid systems, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 137 subclass 170.4]    170.4With conditioning trap or chamber:
 This subclass is indented under subclass 170.1.  Apparatus wherein the means for preserving or modifying the pressure of the gas includes an enclosed vessel through which such fluids pass and in which they are retained for a time.

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571+,for plural tanks or compartments, including traps, connected for serial flow.
613+,for single flow path devices with serial valves which may comprise alternately seated inlet and outlet valves.

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222Dispensing,   subclasses 424.5+ for dispensers including stationary trap chambers, and especially subclass 442 for such arrangements in which a vent is provided for the trap chamber. See also Class 222, Class Definition, "Stationary Traps," for a discussion of the disposition of stationary trap chamber structures and for a listing of other classes containing similar structures.
516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclasses 115+ for processes of or compositions for or subcombination compositions for the breaking of or inhibiting of foam colloid systems, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 137 subclass 170.5]    170.5Recarbonation:
 This subclass is indented under subclass 170.4.  Apparatus having means associated with the vessel for withdrawing evolved gas from the mixture and means whereby some or all of such evolved gas may be returned to the mixture for reentrainment therein before being discharged by the apparatus.

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599.01through 601.21, for systems dividing into parallel flow lines then recombining.

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261Gas and Liquid Contact Apparatus,   appropriate subclasses for devices for contacting liquids and gases, generally.
516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclasses 115+ for processes of or compositions for or subcombination compositions for the breaking of or inhibiting of foam colloid systems, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 137 subclass 170.6]    170.6With trap or chamber by-pass:
 This subclass is indented under subclass 170.4.  Apparatus having conduits or passages so connecting portions of the apparatus that the mixture may be directed to a point of discharge without passing through the vessel so that it is possible to discharge either material which has been held or treated in the vessel, material which has not been so treated, or a desired combination of such materials.

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599.01through 601.21, for systems dividing into parallel flow lines then recombining.

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222Dispensing,   subclass 318 for dispensers having means to by-pass or to otherwise return the material to the source.
516Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting,   subclasses 115+ for processes of or compositions for or subcombination compositions for the breaking of or inhibiting of foam colloid systems, when generically claimed or when there is no hierarchically superior provision in the USPC for the specifically claimed art.
  
[List of Patents for class 137 subclass 171]    171Fluid separating traps or vents:
 This subclass is indented under subclass 154.  Apparatus which separates and provides for the removal of one or more of the diverse fluids from the system.
(1) Note. The material may be collected in an auxiliary chamber or trap prior to discharge, or it may be vented directly through a controlled or restricted outlet in the system. In either case, a given discharge means is intended to relieve the system of one fluid but not others.
(2) Note. Mere vents for gas in diverse fluid containing pressure systems are found in this subclass.

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213+,for venting gas from the supply stored over or used to displace a liquid.
312+,for collection of external condensate or drip.

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34Drying and Gas or Vapor Contact With Solids,   subclass 125 for liquid removal devices for steam drying apparatus.
96Gas Separation: Apparatus,   for apparatus for gas separation, per se, particularly subclasses 155+ for degasifying means for liquid, per se.
210Liquid Purification or Separation,   appropriate subclasses for separation of liquids from liquids or solids.
236Automatic Temperature and Humidity Regulation,   appropriate subclasses, especially subclass 41 and 53-60 for thermally operated or responsive traps or vents in fluid handling system for automatic temperature regulation.
  
[List of Patents for class 137 subclass 172]    172Liquids separated from liquid:
 This subclass is indented under subclass 171.  Separating traps wherein the diverse fluids are liquids of different specific gravity.
(1) Note. Systems containing diverse fluids which are liquids will be found in subclass 154 of this group where discrimination is not involved.

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210Liquid Purification or Separation,   subclasses 513+ for liquid separating decanters, and see the search notes thereunder.
222Dispensing,   subclasses 62 and 395 for dispensers having a liquid pressure fluid for displacing the material to be dispensed.
  
[List of Patents for class 137 subclass 173]    173Plural discriminating outlets for diverse fluids:
 This subclass is indented under subclass 171.  Separating traps which are provided with plural discriminating outlets each of which permits outflow of one fluid and prevents outflow of other diverse fluids.

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236Automatic Temperature and Humidity Regulation,   subclass 53 for traps having a float controlled liquid outlet and a thermostatic air valve.
  
[List of Patents for class 137 subclass 174]    174Common actuator for control valves:
 This subclass is indented under subclass 173.  Separating traps wherein the outlets are valve controlled and the valves have a common actuator.

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595,for systems having a plural noncommunicating flow paths with a common valve operator.
601.01through 601.12, for systems dividing into parallel flow lines then recombining including valves having a common operator therefor.
607,for systems having a multiple inlet with a single outlet, a flow control valve in each inlet, and a common valve operator.
862through 871, for systems having a flow control means for branched passages and a common valve operator.
  
[List of Patents for class 137 subclass 175]    175Choke or restricted passage gas bleed:
 This subclass is indented under subclass 173.  Separating traps wherein one of the discriminating outlets is a restricted gas bleed, which by its small size acts or tends to act as a discriminating gas outlet.

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179+,for a discriminating liquid outlet with a nondiscriminating gas vent in a diverse fluid containing pressure system.
583+,for distribution systems having a gas vent and at least one other flow passage, and see the search notes to subclasses 583 and 587.

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251Valves and Valve Actuation,   subclass 117 for valves having a restrictor in parallel flow relation thereto, and subclasses 118+ for valves combined with material guides or restrictors, and see the search notes to subclass 118.
  
[List of Patents for class 137 subclass 176]    176From above liquid level:
 This subclass is indented under subclass 175.  Separating traps wherein the gas bleed has its inlet above the normal maximum liquid level in the trap chamber.
  
[List of Patents for class 137 subclass 177]    177Discriminating outlet for liquid:
 This subclass is indented under subclass 171.  Separating traps wherein the separating trap is provided with a discriminating outlet which permits outflow of liquid but prevents outflow of gas.

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159+,for traps having discriminating liquid outlets, the liquid in the trap controlling gas pressure application to the trap for discharging the liquid.

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222Dispensing,   subclass 66 for empty container cut-offs for dispensers.
236Automatic Temperature and Humidity Regulation,   subclasses 53 through 60for temperature responsive liquid separating traps.
  
[List of Patents for class 137 subclass 178]    178With alternately operated inlet and outlet valves:
 This subclass is indented under subclass 177.  Separating traps further provided with a valve controlling a trap chamber inlet which is operated alternately with the outlet valve.
(1) Note. See the main class definition, Lines With Other Classes and Within This Class, Plural Valves, and also Subclass References to the Current Class, for search notes on plural valves in fluid handling systems.

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596+,for distribution systems having alternately seated stop and waste valves, and see the search notes thereto.
602+,627.5 and 861+, for other alternately seated valves.

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222Dispensing,   subclasses 425+ , especially subclasses 445+ and 450+ for dispensers with stationary traps and cut-offs for inlet and outlet, which are ordinarily alternately seated.
  
[List of Patents for class 137 subclass 179]    179With non-discriminating gas vent or liquid discharge:
 This subclass is indented under subclass 177.  Separating traps provided with a nondiscriminating gas vent, an additional nondiscriminating liquid outlet or an additional control of the discriminating liquid outlet, the additional control being such as to give a nondiscriminating action to the discriminating outlet.

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175,for plural discriminating outlet trap devices in which one outlet is a choked or restricted passage gas bleed.
583+,for distribution systems with plural openings, one of which is a gas vent, and see the search notes to subclasses 583 and 587.
  
[List of Patents for class 137 subclass 180]    180Abnormal pressure responsive liquid blow-off or drain:
 This subclass is indented under subclass 179.  Separating traps wherein the additional liquid outlet or additional control of the liquid outlet responds to a system pressure either above or below the normal operating pressure.

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493,for line condition change responsive valves operated by flow in either direction, i.e., high or low pressures on either side.
  
[List of Patents for class 137 subclass 181]    181Manual control:
 This subclass is indented under subclass 179.  Separating traps wherein the nondiscriminating fluid discharge is manually controlled.
(1) Note. See the class definition, Lines With Other Classes and Within This Class, (3) Manual Control, Resetting, etc., and also Subclass References to the Current Class, for search notes on manual valve actuation in this and related classes.
  
[List of Patents for class 137 subclass 182]    182With auxiliary inlet or by-pass valve:
 This subclass is indented under subclass 177.  Separating traps further provided with a nondiscriminating valve in the trap inlet or a valve providing a by-pass of the trap.

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597,and 602+, for distribution systems having multiple inlets with multiple and single outlets respectively, and see the search notes to subclass 602.
599.01through 601.21, for systems dividing into parallel flow lines then recombining.
  
[List of Patents for class 137 subclass 183]    183With fluid responsive valve:
 This subclass is indented under subclass 177.  Separating traps wherein the discrimination is obtained by an outlet valve which is responsive to a fluid condition.

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455+,for line condition change responsive valves of the safety cut-off, pop, pressure regulating, safety or check types, and see the notes to subclass 455 for search notes on condition responsive valves in this and related classes.

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236Automatic Temperature and Humidity Regulation,   subclasses 53 through 60for temperature responsive liquid separating traps in devices for automatic temperature regulation.
  
[List of Patents for class 137 subclass 184]    184Successively opened valves:
 This subclass is indented under subclass 183.  Separating traps having a plurality of successively opened liquid outlet valves.
(1) Note. See the class definition,Lines With Other Classes and Within This Class, Plural Valves, and also Subclass References to the Current Class, for search notes on plural valves in this and related classes.

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628+,for sequentially progressive actuation of plural valves to opening or closing position, and see the search notes to subclass 628.
861+,for distribution systems having plural valved branches, and see the search notes to subclass 861.
  
[List of Patents for class 137 subclass 185]    185Gas collecting float (e.g., inverted bucket):
 This subclass is indented under subclass 183.  Separating traps wherein the valve closes in response to the collection of gas in an open-bottom float.

SEE OR SEARCH THIS CLASS, SUBCLASS:

409+,for float operated valves, and see the search notes to subclass 409.
  
[List of Patents for class 137 subclass 186]    186Downstream from valve:
 This subclass is indented under subclass 185.  Separating traps wherein the float is located downstream from the valve.
  
[List of Patents for class 137 subclass 187]    187Level responsive:
 This subclass is indented under subclass 183.  Separating traps wherein the valve is controlled by the level of liquid in the trap.

SEE OR SEARCH THIS CLASS, SUBCLASS:

159+,for liquid level control of gas pressure discharge type feed-traps.
386+,for liquid level responsive valves for other and general uses, and see the search notes to subclass 386.

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222Dispensing,   subclasses 64+ for dispensers controlled by material level.
  
[List of Patents for class 137 subclass 188]    188Weight or pressure:
 This subclass is indented under subclass 187.  Separating traps wherein the valve is responsive to the weight or pressure of accumulated liquid.

SEE OR SEARCH THIS CLASS, SUBCLASS:

403+,for control devices responsive to the weight of accumulated liquid, and see the search notes to subclass 403.
  
[List of Patents for class 137 subclass 189]    189Gravitating vessel:
 This subclass is indented under subclass 188.  Separating traps wherein liquid accumulates in a vessel which lowers in response to the weight of the liquid which lowering controls the valve.

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161,and 162+, for similar subject matter with a control for applying gas pressure to the trap to force the discharge thereof as to a boiler.
408,for gravitating tank devices responsive to and controlling liquid level, and see the search notes thereto.
  
[List of Patents for class 137 subclass 190]    190Sinking or bucket type float:
 This subclass is indented under subclass 189.  Separating traps wherein the vessel is an open-topped float which floats in liquid and sinks when filled with liquid.

SEE OR SEARCH THIS CLASS, SUBCLASS:

404,for liquid level responsive or maintaining systems controlled by a sinking or bucket type float, and see the search notes thereto.
  
[List of Patents for class 137 subclass 191]    191Servo-control:
 This subclass is indented under subclass 190.  Separating traps wherein the float operates a servo-mechanism or pilot valve controlled device which in turn operates the valve.

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195,for servo control with level responsive means of the float type in these devices.
412+,for servo relay operation of control in float controlled valves.

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251Valves and Valve Actuation,   subclasses 25+ for fluid pressure type servo-motors for valve actuation, and see the search notes to subclass 25 and subclasses 129+ for electrical actuators for valves.
  
[List of Patents for class 137 subclass 192]    192Float:
 This subclass is indented under subclass 187.  Separating traps wherein the level responsive means is a float.

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386+,for liquid level responsive or maintaining systems, especially 409+ for float controlled valves, and see the search notes to subclasses 386 and 409.

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222Dispensing,   subclasses 67+ for float operated flow controllers in dispensers.
  
[List of Patents for class 137 subclass 193]    193With main line gas outlet from trap chamber:
 This subclass is indented under subclass 192.  Separating traps wherein the trap chamber is provided with an inlet for gas and liquid, a discriminating outlet for liquid and a nondiscriminating outlet for the main flow of the gas to a gas distribution system.

SEE OR SEARCH THIS CLASS, SUBCLASS:

173,for devices having a gas and liquid inlet and discriminating outlets for both fluids.
179,for devices having a discriminating outlet for liquid and a nondiscriminating vent for gases, i.e., one which does not discharge the main flow of the material being handled.
  
[List of Patents for class 137 subclass 194]    194With outlet extending above liquid in trap:
 This subclass is indented under subclass 192.  Separating traps wherein the discriminating liquid outlet pipe rises above the normal liquid level in the trap chamber, thus requiring the gas pressure in the chamber to discharge the liquid.

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206+,for diverse fluid containing pressure systems in which gas is used as a liquid displacing means, and see the search notes to subclass 206.
590+,for distribution systems having internally extending pipes, and see the search notes to subclass 590.

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222Dispensing,   subclass 373 for fluid pressure discharge of material from a dispenser trap.
  
[List of Patents for class 137 subclass 195]    195Servo-control:
 This subclass is indented under subclass 192.  Separating traps wherein the liquid outlet valve is controlled by a servo mechanism or pilot valve operated means which is in turn controlled by the float.

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191,for similar devices in which the level responsive means responds to weight or pressure of the accumulated fluid, and see the search notes thereto.

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236Automatic Temperature and Humidity Regulation,   subclass 55 for a float controlled pilot with a thermostatically controlled trap in automatic temperature regulation devices.
251Valves and Valve Actuation,   subclasses 25+ for fluid pressure servo-motors for valve actuation, and see the search notes to subclass 25.
  
[List of Patents for class 137 subclass 196]    196With pressure balanced outlet valve:
 This subclass is indented under subclass 192.  Separating traps wherein a plurality of coacting liquid outlet valves are arranged to act in opposition or a single outlet valve is provided with opposed surfaces to cancel out the effect of internal pressure on the valve.

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251Valves and Valve Actuation,   subclasses 281+ for balanced valves of general utility and see the search notes thereto.
  
[List of Patents for class 137 subclass 197]    197Discriminating outlet for gas:
 This subclass is indented under subclass 171.  Separating traps wherein the trap is provided with an outlet through which outflow of a gas is permitted but outflow of a liquid or diverse gas therethrough is prevented.

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173+,for diverse fluid containing pressure systems having plural discriminating outlets or vents.
175+,for traps having a choke or restricted gas bleed.
213+,for liquid level responsive gas vents for boilers or other gas pressure over liquid devices which may also be utilized as safety or warning devices or whistles.
386,for liquid level responsive or maintaining devices involving hygroscopic means.
388,for liquid excluding devices for gas inlets or outlets in systems which are not diverse fluid containing pressure systems.
583+,for distribution systems having plural passages, one of which is a gas vent, and see the search notes to subclasses 583 and 587.

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96Gas Separation: Apparatus,   for apparatus for gas separation, per se, particularly subclasses 155+ for degasifying means for liquid, per se.
222Dispensing,   subclass 69 for float operated controllers for dispensing container vents.
  
[List of Patents for class 137 subclass 198]    198With reverse flow stop or pressure regulating valve:
 This subclass is indented under subclass 197.  Separating traps further provided with a pressure responsive valve in the gas outlet which prevents reverse flow or regulates the system gas pressure.

SEE OR SEARCH THIS CLASS, SUBCLASS:

455+,for line condition change responsive valves, especially subclass 496 for those having separate reactor surface and closing in response to reverse flow, subclass 505 for the pressure regulating type, and subclasses 511+ for check valves, especially subclasses 517+ for those biased open.
  
[List of Patents for class 137 subclass 199]    199Fluid sensing valve:
 This subclass is indented under subclass 197.  Separating traps wherein the discrimination is obtained by an outlet valve which is responsive to a fluid.

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183+,for fluid responsive valves comprising discriminating outlets for liquids.
455+,for line condition change responsive valves of general types, and see the search notes to subclass 455.
  
[List of Patents for class 137 subclass 200]    200With vaporized liquid stop:
 This subclass is indented under subclass 199.  Separating traps wherein the valve or an additional device functions to stop normally liquid fluid which is vaporized, such as steam, in the system.
  
[List of Patents for class 137 subclass 201]    201With separate return for condensate:
 This subclass is indented under subclass 200.  Separating traps wherein a separate return path is provided from the trap to the system for condensed vapor.

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156+,for devices of this type where the condensed vapor is returned to a boiler or other receivers under higher pressure.
  
[List of Patents for class 137 subclass 202]    202Float responsive:
 This subclass is indented under subclass 199.  Separating traps wherein the valve is responsive to a float member.

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192+,for devices of this type which are discriminating for liquids.
409+,for float controlled valves, and see the search notes to subclass 409.
  
[List of Patents for class 137 subclass 203]    203With liquid emptying means:
 This subclass is indented under subclass 171.  Separating traps wherein the provision for removal of a fluid from the system is a nondiscriminating liquid outlet.
(1) Note. Nondiscriminating outlets for gas in systems of this type have been placed in the subclass under which this subclass is indented.

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179+,for systems of this type having both discriminating and nondiscriminating outlets for liquid.
861+,for distribution systems having plural valved outlets, and see the search notes to subclass 861.
  
[List of Patents for class 137 subclass 204]    204Self-emptying:
 This subclass is indented under subclass 203.  Separating traps wherein the outlet empties the system of liquid of its own volition, as when the system pressure is removed.

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183+,and 199+, for fluid responsive valves in diverse fluid containing pressure systems.
396+,for self-emptying tanks which are level responsive.
  
[List of Patents for class 137 subclass 205]    205Liquid filling by evacuating container:
 This subclass is indented under subclass 154.  Apparatus providing means whereby a container may be filled with a liquid by evacuating the container either prior to or simultaneously with the liquid filling.

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130+,for siphon systems with discharge controlling receiver.
571+,for distribution systems comprising plural tanks connected for series flow.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclasses 59+ for filling devices in which a separable receiver is placed under vacuum for filling.
166Wells,   subclass 165 and the subclasses there noted for receptacles used in wells and filled by liquid because the receptacle has been evacuated or is filled with air at a pressure lower than the surrounding liquid.
417Pumps,   subclasses 118+ and particularly subclasses 148+ for means for pumping a liquid by exhausting a gaseous motive fluid from the liquid pump chamber.
  
[List of Patents for class 137 subclass 205.5]    205.5Main line flow displaces additive from shunt reservoir:
 This subclass is indented under subclass 154.  Apparatus including a shunt line having a reservoir therein containing a fluid diverse from that in the main line and wherein the reservoir material is fed into the main line, without mixing with main line material in the reservoir, by main line flow into the shunt due to differential pressure along the main line.

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268,for means to entrain a solid material into a fluid handling system and see the search notes thereunder.
564.5,for a line responsive follower type feeder in a shunt line.
  
[List of Patents for class 137 subclass 206]    206Gas pressure storage over or displacement of liquid:
 This subclass is indented under subclass 154.  Apparatus wherein a gas under pressure is provided over a body of liquid or is utilized to displace a liquid and a definite coaction exists between the gas and liquid which affects the system.
(1) Note. The usual purpose for mere storage of gas over liquid is for an air cushion or surge eliminating means.

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145,for application of pressure to liquid in a siphon chamber to initiate a flow through a siphon connected thereto.
156+,for liquid feed traps utilizing a gas pressure for discharge.
170.1+,for diverse fluid containing pressure systems in which the fluids are in the form of a liquid impregnated with gas and there are means for controlling the degree of froth or foam formed in the handling of such fluids.

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222Dispensing,   subclasses 61+ , 258, 261 to 263 and 396+ for dispensers with fluid pressure discharge assistants.
417Pumps,   subclasses 118+ for liquid pumping by supplying or exhausting gaseous motive fluid to or from a liquid pumping chamber.
  
[List of Patents for class 137 subclass 207]    207Surge suppression:
 This subclass is indented under subclass 206.  Apparatus wherein the gas is trapped in a dome over a liquid from a liquid distribution system to suppress or absorb pressure surges in the liquid system.

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568,and 593, for surge chambers for distribution systems in which a head of liquid supplies the cushion or bias in the system. The chamber may be closed, but air pressure is not relied on for surge suppression.

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138Pipes and Tubular Conduits,   subclasses 26+ for pressure compensators for pipes and tubular conduits.
417Pumps,   subclasses 543+ for expansible chamber type pumps having a pulsation damping means of the direct contact compressible fluid type.
  
[List of Patents for class 137 subclass 207.5]    207.5With return of liquid to supply:
 This subclass is indented under subclass 206.  Apparatus in which the liquid in one part of the system is allowed to flow back, is forced back, or is by-passed back to the source of supply, in order to empty the system for cleaning, storage, etc.

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239,for fluid handling systems of general application having means for reversing the normal direction of flow of the fluid for assisting in the cleaning of such systems.

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222Dispensing,   subclass 318 for dispensing devices embodying discharge assisting means and having a bypass or return to supply.
  
[List of Patents for class 137 subclass 208]    208Plural units:
 This subclass is indented under subclass 206.  Apparatus wherein a plurality of similarly functioning gas pressure over liquid units are provided.

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255+,for fluid handling systems comprising plural tanks with parallel outflow, and see the search notes to subclass 225.
  
[List of Patents for class 137 subclass 209]    209With gas maintenance or application:
 This subclass is indented under subclass 206.  Apparatus wherein means are provided to maintain or apply the gas pressure over or to the liquid.

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145,and 147+, for pressure fluid supply for starting siphons.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclass 19 for puncturing gas pressure reservoirs for filling dispensers.
222Dispensing,   subclass 209 for resilient wall fluid pressure generating pump or pulsator for dispensers, subclasses 399 for gas pressure supplying reservoirs and 401+ for container mounted fluid pressure generating pump or pulsator.
  
[List of Patents for class 137 subclass 210]    210Gas carried by or evolved from liquid:
 This subclass is indented under subclass 209.  Apparatus in which the gas is derived from a liquid not necessarily the liquid over which the gas acts.

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62Refrigeration,   subclasses 45.1+ for process and apparatus for handling liquefied gas as a commodity including steps or means involving pressure or temperature control special to liquefied gas and more than required for other liquids under gas pressure.
  
[List of Patents for class 137 subclass 211]    211Gas injectors:
 This subclass is indented under subclass 210.  Apparatus with a device to add or inject gas into the liquid of the system to replenish the gas over the liquid.

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261Gas and Liquid Contact Apparatus,   appropriate subclasses for carbonators, per se.
  
[List of Patents for class 137 subclass 211.5]    211.5Gas injected by liquid pressure or flow:
 This subclass is indented under subclass 209.  Apparatus including means to apply gas pressure over the liquid said means utilizing the pressure of flow of the liquid to apply the gas.

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211,for gas injectors utilizing the pressure or flow of the liquid in which the gas is carried into the storage tank by the liquid.
  
[List of Patents for class 137 subclass 212]    212Unitary mounting for gas pressure inlet and liquid outlet:
 This subclass is indented under subclass 209.  Apparatus wherein the gas pressure inlet and liquid outlet have a common mounting adapted for manipulation as a unit for positioning or removal from a gas and liquid container.

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317+,for devices for tapping a container under pressure which frequently comprise the liquid outlet subcombination of the subject matter under this definition.
594+,and 625.18+, for fluid distribution systems including noncommunicating flow paths where one flow path may be for gas and the other for liquid.

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222Dispensing,   subclasses 394+ for dispensers having fluid pressure discharge assistants, especially subclass 399 for those having a gas reservoir and subclasses 401+ for those having a pressure generating pump mounted on the supply container, and see the search notes to subclass 394.
  
[List of Patents for class 137 subclass 213]    213With liquid level responsive gas vent or whistle:
 This subclass is indented under subclass 206.  Apparatus wherein a gas vent or whistle is opened in response to a predetermined liquid level.
(1) Note. An example of such apparatus is a low water level steam exhaust and signal for a boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

197+,for discriminating gas outlets or vents which may be liquid level responsive.
386+,for liquid level responsive or maintaining systems.
558,for liquid level indicators involving release of a separate gas for their operation, or of internal gas pressure when gas is the only fluid in the system. The use of whistles with gas exhaust devices as found in diverse fluid containing pressure systems is so common in the art that no cross reference is made of patents involving such subject matter to subclass 558. The search note under subclass 558 directs that search be made in subclasses 213+.

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116Signals and Indicators,   subclasses 137+ for whistles, per se.
222Dispensing,   subclass 39 for audible signals for dispensers and subclass 69 for float controlled vents for dispensers.
446Amusement Device: Toys,   subclasses 204+ for a sounding toy comprising a whistle.
  
[List of Patents for class 137 subclass 214]    214Combined high and low level responsive:
 This subclass is indented under subclass 213.  Apparatus wherein the gas vent or whistle is opened in response to a high and low liquid level.

SEE OR SEARCH THIS CLASS, SUBCLASS:

391,for liquid level control of both inflow and outflow in a tank.
  
[List of Patents for class 137 subclass 215]    215BACK FLOW PREVENTION BY VACUUM BREAKING (E.G., ANTI-SIPHON DEVICES):
 This subclass is indented under the class definition.  Apparatus which stop reverse flow of a liquid in a distribution system by preventing or eliminating the vacuum condition which would cause the reverse flow, such as a condition which would start siphoning.
(1) Note. The normal flow in these systems is not of the siphon type.

SEE OR SEARCH THIS CLASS, SUBCLASS:

143,for breakers in flow devices which are intended to act as siphons.
441,for refill pipes which may act as vacuum breakers.
526,for vacuum relief valves, per se.
583+,for distribution systems having plural openings, one of which is a gas vent, and see the search notes to subclasses 583 and 587.

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   subclass 34 for reverse flow prevention in choked pressure type servo motors which actuate valves.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 216]    216Air vent in liquid flow line:
 This subclass is indented under subclass 215.  Apparatus wherein the back flow is prevented by an air vent or gap in the liquid flow line.

SEE OR SEARCH THIS CLASS, SUBCLASS:

143,for vent type breakers in flow devices which are intended to act as siphons.
583+,for distribution systems having plural flow passages, one of which is a gas vent, and see the search notes to subclasses 583 and 587.
  
[List of Patents for class 137 subclass 216.1]    216.1With liquid seal in liquid flow line:
 This subclass is indented under subclass 216.  Apparatus including a liquid seal means in the liquid flow line.

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247+,for liquid seals.

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4Baths, Closets, Sinks, and Spittoons,   subclasses 211 , 218 and 219 for ventilation of house plumbing or sewers.
  
[List of Patents for class 137 subclass 216.2]    216.2Automatic valve in vent line:
 This subclass is indented under subclass 216.1.  Subject matter including an automatic valve in the vent line.

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217,for valved vents without a liquid seal means.
  
[List of Patents for class 137 subclass 217]    217Valved:
 This subclass is indented under subclass 216.  Apparatus wherein the air vent is provided with a valve.

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216.2,for valved vents in a flow line of the instant type including a liquid seal.
526,for vacuum relief valves, per se.

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4Baths, Closets, Sinks, and Spittoons,   subclass 426 for vented siphon bowls.
  
[List of Patents for class 137 subclass 218]    218With co-acting valve in liquid flow path:
 This subclass is indented under subclass 217.  Apparatus wherein a valve is provided in the liquid flow path which operates in conjunction with the air vent valve.

SEE OR SEARCH THIS CLASS, SUBCLASS:

861+,for distribution systems having plural valved flow paths, and see the search notes to subclass 861.
  
[List of Patents for class 137 subclass 219]    219LARNER-JOHNSON TYPE VALVES; I.E., TELESCOPING INTERNAL VALVE IN EXPANDED FLOW LINE SECTION:
 This subclass is indented under the class definition.  Flow control devices comprising a flow line having a contracted portion, a valve seat adjacent said contracted portion and an internal coaxial valve part comprising telescoping members, one of which is a movable needle or valve head which engages said seat.
(1) Note. These valves are commonly known as Johnson or Larner-Johnson valves, and are used principally in water conduits providing for very large flow, as in dams and hydraulic installations associated therewith.
(2) Note. In addition to one or two moving valve heads or needles the internal part of the device comprises one or more stationary members around which flow occurs. The stationary members may be merely guides for the needles or they may complete a pressure chamber arrangement in cooperation with the movable member or members, but in either case a flow channel must be formed around a stationary member and between it and the wall of the flow line; i.e., the parts of the internal device must be surrounded by flowing fluid, except for the supports or connections between the stationary member and the wall.
(3) Note. The contracted portion of the flow line constitutes a region of relatively low fluid pressure, and the usual streamlining of the needle or stationary part, or both, provides a balanced or easily controlled valve suitable for controlling large flows.
(4) Note. The inner valve element frequently comprises a closed top-shaped body having fluid pressure chambers therein, but may comprise annular members having annular chambers therebetween, or less streamlined forms. In any form the valve head always lies in an enlarged portion of the flow line.
(5) Note. The valve may be operated (1) by fluid pressure derived either from the line or from an external source, the expansible chambers comprising (a) the telescoping valve body (b) a separate motor within the valve body or (c) a mechanical movement connected fluid pressure motor external to the line, (2) by mechanical movement or electric motor means either within or outside of the flow line; or (3) by combinations of fluid pressure operating means and nonfluid operated means.

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455+,for line condition responsive valves of other types.

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   appropriate subclasses for valves and valve actuation generally, especially subclasses 12+ for fluid actuated or retarded valves of other types, and subclasses 123+ for combined valves and restrictors in which the valve is located at the point of greatest restriction in the line.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 220]    220Line condition change responsive:
 This subclass is indented under subclass 219.  Flow control devices in which the valve is actuated in response to a change in condition of the fluid handled.
(1) Note. Such devices as pressure regulators and excess or reverse flow responsive valves, and combinations of the above with each other or with manual or other external controls, are included.

SEE OR SEARCH THIS CLASS, SUBCLASS:

455+,for line condition responsive valves of other types, especially subclasses 485+ for pilot or servo-controlled condition change responsive valves.
  
[List of Patents for class 137 subclass 221]    221Internal servo-motor with internal pilot valve:
 This subclass is indented under subclass 219.  Flow control devices in which a controlled motor device comprising a pilot operated or servo-mechanism is involved, the motor device and its pilot or control valve being located within the internal part of the valve, i.e., the part comprising the telescoping support and the needle or movable valve head lying within the flow passage.

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   subclasses 25+ for valve actuation involving fluid type pilot or servo type motors, and see the search notes to subclass 25.
  
[List of Patents for class 137 subclass 222]    222Pilot controlled passage in nose or needle:
 This subclass is indented under subclass 221.  Flow control devices in which the pilot valve controls a passage through the needle or movable part of the valve means internal to the flow line.

SEE OR SEARCH CLASS:

251Valves and Valve Actuation,   subclasses 38+ for choked pressure type servo motors for valve actuation in which the pilot valve is seated in the motor or valve element.
  
[List of Patents for class 137 subclass 223]    223INFLATABLE ARTICLE (E.G., TIRE FILLING CHUCK AND/OR STEM):
 This subclass is indented under the class definition.  Apparatus comprising valved inflation stems of the type attached to pneumatic tires and analogous inflatable articles, including filling and/or relief extensions of such stems, valved filling chucks or the type attached to pressure fluid supplying conduits and employed to inflate such articles by means of the inflation stems, and combinations of such inflation stems and filling chucks.
(1) Note. Relief and filling extensions to be attached to inflation stems have means to hold open the valve normally present in such stems.
(2) Note. The claiming of a source of supply of inflating fluid by name only does not exclude patents otherwise classifiable herein.

SEE OR SEARCH THIS CLASS, SUBCLASS:

320+,for means comprising a tap or other attachable flow conduit which can be applied to a container under pressure to open a valve therein for transfer of fluids.
455+,for line condition change responsive valves, e.g., safety and check valves.

SEE OR SEARCH CLASS:

138Pipes and Tubular Conduits,   subclasses 89.1 through 89.4for inflation stem closures and caps.
141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclass 4 for methods of charging separable receivers with gas, subclass 38 for filling apparatus for filling tires with gas and liquid, and appropriate subclasses for charging tires with gas, comprising in addition to the chuck and/or stem a significantly claimed source of supply, means for holding or supporting the tire or other Class 141 feature.
152Resilient Tires and Wheels,   subclasses 415+ for tire inflating devices combined with vehicle or wheel structure.
222Dispensing,   subclasses 3+ for gas dispensers.
  
[List of Patents for class 137 subclass 224]    224With pressure-responsive pressure-control means:
 This subclass is indented under subclass 223.  Apparatus having fluid pressure responsive means permanently associated therewith for controlling the pressure therein or in the inflatable article during the inflating operation or while the inflatable article is in use.
(1) Note. If the pressure responsive control device is associated with the stem and controls the article in use, it does not interfere with the inflation operation.

SEE OR SEARCH THIS CLASS, SUBCLASS:

230,for relief valves adapted to be mounted on the end of a conventional inflation stem, and not having a filling passage. See (1) Note.
494+,particularly subclasses 505+ and 511+ for pressure regulators and relief valves of general utility with and without separate reactor surfaces, respectively.
  
[List of Patents for class 137 subclass 224.5]    224.5Pulsating:
 This subclass is indented under subclass 224.  Devices wherein the fluid is dispensed in successive charges until the predetermined pressure is reached.
  
[List of Patents for class 137 subclass 225]    225Diaphragm, bellows or expansible tube:
 This subclass is indented under subclass 224.  Apparatus having a diaphragm, bellows or expansible tube as the pressure responsive means.

SEE OR SEARCH THIS CLASS, SUBCLASS:

510,for relief valves of general utility closing in the direction of fluid flow and having a reactor surface comprising flexible diaphragm or bellows.
777+,for expansible chamber devices, per se, and see the notes to subclass 777.
793+,for diaphragms and bellows, per se, and see the notes to subclass 793.
  
[List of Patents for class 137 subclass 226]    226Co-axial inflation and relief valves:
 This subclass is indented under subclass 224.  Apparatus having inflation and relief valves on a common axis.
(1) Note. See the class definition, Section 4 for search notes on plural valves in this and related classes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

228,and 230, for other relief valves associated with inflation stems.
493+,for line condition responsive valves of the bi-directional type, including plural valves of which one may relieve high pressure and another relieve vacuum or reverse pressure.
505.11,for combined pressure regulators and relief valves of general utility.
512.2,614.16+, 630+, and 637.2+, for other valves mounted on a common axis.
  
[List of Patents for class 137 subclass 227]    227With gauge or indicator:
 This subclass is indented under subclass 223.  Apparatus having a fluid pressure gauge or indicator combined therewith.

SEE OR SEARCH THIS CLASS, SUBCLASS:

224+,for inflation devices having fluid pressure responsive pressure control means in association with a fluid pressure gauge or indicator or wherein the pressure responsive means is also a gauge or indicator or part thereof.
557,for combinations of fluid delivery systems other than inflatable article filling chucks or stems with fluid pressure responsive gauges or indicators.
524,for check and safety valves having means to adjust and indicate the setting of the biasing means.

SEE OR SEARCH CLASS:

73Measuring and Testing,   subclasses 146.2+ for fluid pressure gauges connected to a tire value stem and mounted on the stem or a vehicle carrying the stem and subclasses 700+ for fluid pressure gauges, per se.
116Signals and Indicators,   subclass 34 for signals, indicators and alarms for indicating when tire pressure is different from a desired valve.
  
[List of Patents for class 137 subclass 228]    228With deflating means:
 This subclass is indented under subclass 227.  Apparatus having means for releasing fluid from the article being inflated while the gauge or indicator remains combined with the filling chuck and/or stem.

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230,for stem attached relief valves.
511+,for relief valves of general utility in which the pressure fluid acts directly on the valve head, without separate reactor surfaces.
  
[List of Patents for class 137 subclass 229]    229Selectively connected:
 This subclass is indented under subclass 227.  Apparatus having means whereby the gauge or indicator may be selectively placed in or out of communication with the filling passage of the chuck or stem.
  
[List of Patents for class 137 subclass 230]    230Stem attached relief valve:
 This subclass is indented under subclass 223.  Valved devices which are adapted to be mounted in the end of a conventional pneumatic tire inflation stem to relieve excess pressure.
(1) Note. These valves each include a projection which holds the conventional valve open when it is in place.
(2) Note. Since these valves do not include an inflow passage, they must be removed during inflation.

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224+,for tire pressure relief valves integral with tire inflating stems and/or chucks, and intended to remain in place during inflation. See (2) Note.
320+,for tapping connections to valved containers which are under pressure, the connection comprising or carrying means for opening the valve after or during the connecting operation.
494+,and 511+, for relief valves with and without separate reactor surfaces, respectively some of which are disclosed for use with inflatable articles.
  
[List of Patents for class 137 subclass 231]    231With coupling means:
 This subclass is indented under subclass 223.  Apparatus having significant structure for connecting a filling chuck to an inflation stem, or an inflation stem to a second inflation stem or filling tube, the second stem or tube usually being permanently associated with a tire.
(1) Note. The mere statement that a chuck or stem is screw threaded or flanged for coupling is not regarded as significant coupling structure for this subclass.

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614.02+,and 614.05, for a valve operated by coupling motion of the flow path sections.
798+,for nonvalved couplings joining two or more flow lines in fluid connecting relation, and see the search notes to subclass 798.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,   subclasses 383+ for couplings between a separable dispenser and receiver, and see the search notes to subclass 223 of this class (137).
251Valves and Valve Actuation,   subclasses 142+ for a valve associated with a flow path, particularly subclasses 149+ wherein the valve is operated by the act of joining flow path sections.
  
[List of Patents for class 137 subclass 232]    232With cap:
 This subclass is indented under subclass 223.  Apparatus, usually of the inflation stem type, having a cap or closure for protecting and/or sealing the end thereof.

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800,for closures associated with devices of this class, and see the search notes thereto.

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49Movable or Removable Closures,   appropriate subclasses, for closures of the type provided for, and see the search notes thereto in section IV for the loci of closures in other classes.
138Pipes and Tubular Conduits,   subclasses 89.1 through 89.4for inflation stem type closures and plugs.
  
[List of Patents for class 137 subclass 233]    233Valve actuating, assembling or locking means on cap:
 This subclass is indented under subclass 232.  Apparatus in which the cap is provided with means for actuating, locking in place, or assembling a valve located in an inflation stem.

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315.01through 329.4, for a fluid handling system with repair, tapping, or assembly means.
613+,for a flow path with serial valves and/or closures.

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152Resilient Tires and Wheels,   subclass 431 for combined valve stem caps and tools, the tool usually being employed to manipulate a valve in the stem.
  
[List of Patents for class 137 subclass 234]    234Valve manually seated:
 This subclass is indented under subclass 233.  Apparatus in which the valve which is actuated, locked or assembled is seated by manual manipulation.
(1) Note. The valve may also be provided with biasing means tending to seat it.
  
[List of Patents for class 137 subclass 234.5]    234.5Removable valve head and seat unit (valve insides):
 This subclass is indented under subclass 223.  Devices comprising one or more valve heads and their cooperating seats formed in a sleeve or similar structural unit which is removable as such from a tire stem.

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283+,and 454.2+, for similar structure removable from other fluid handling devices.
  
[List of Patents for class 137 subclass 234.6]    234.6WITH VEHICLE GUIDE OR SUPPORT, E.G., SERVICE STATION:
 This subclass is indented under the class definition.  Fluid handling system combined with means for supporting, guiding or confining a vehicle relative to fluid handling means which supples a fluid to the vehicle, e.g., lubricant or fuel.
(1) Note. Included in this subclass are a fluid system which services vehicles, which system has a defined relationship to an area or body of land or water or a vehicle support or guide even though a nozzle or metering device such as those used in a Class 141, 222 or 239 system is defined.

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236,for other fluid handling systems involving geographic features.

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52Static Structures (e.g., Buildings),   subclasses 169.1+ for a building defined as having a specific relationship to the adjacent terrain, and subclass 174 for a static structure, combined with a defined traffic confining or directing feature wherein no fluid handling feature is defined.
62Refrigeration,   subclass 260 for such apparatus related to the terrain.
184Lubrication,   particularly subclass 1.5 for an automobile gear and crank case system having means specifically related to the crank case.
210Liquid Purification or Separation,   subclasses 170.01 through 170.11for liquid purification or separation means installed in a geographic feature.
222Dispensing,   for a dispensing device with a casing or support not related to a guide or support for a vehicle being serviced.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 236.1]    236.1DISTRIBUTION SYSTEMS INVOLVING GEOGRAPHIC FEATURES:
 This subclass is indented under the class definition.  Fluid handling systems including or specifically related to a particular geographic feature, e.g., a hill, river, ocean shore, city street, etc.
(1) Note. Mere location of a fluid handling system or a portion thereof below the surface of the ground is not sufficient for inclusion in this subclass.
(2) Note. The geos:graphic feature may be either natural or artificial, but must be a clearly defined area on or below the surface of the earth.

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272+,for hydrant type devices including water cranes, which usually have a connection to a water main and a valve located below the surface of the ground. See (1) Note, above.
363+,for casings for fluent material handling devices which separate the device from the ground and support the adjacent earth, as valve and meter wells and pipe line housings. See (1) Note, above.

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239Fluid Sprinkling, Spraying, and Diffusing,   subclasses 201+ for ground or floor embedded sprinkler systems.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 237]    237WITH CLEANER, LUBRICATION ADDED TO FLUID OR LIQUID SEALING AT VALVE INTERFACE:
 This subclass is indented under the class definition.  Fluid handling systems having (1) devices to render the system or parts thereof free from undesirable material, or (2) devices for lubricating the system or parts thereof by adding a lubricating medium to the stream of fluent material carried by the system or (3) devices for preventing leakage between the valve and a solid valve seat by introducing a liquid between the valve and its seat.
(1) Note. Cleaning means for this group requires the installation of additional means or connections to treat the apparatus, not the material being handled, or the manipulation of the system in some special way to secure the cleaning effect.

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15.01through 15.26, for a process of cleaning, repairing, or assembling.
247+,for liquid valves, i.e., those having liquid seats.
544+,for screens, filters, etc., for physically separating solid or unwanted materials from the material being handled.

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222Dispensing,   subclasses 148+ for dispensers with installed cleaning means.
225Severing by Tearing or Breaking,   subclasses 12+ for installed beer pipe cleaners.
251Valves and Valve Actuation,   subclass 355 for lubrication of actuators or parts of a valve in which the lubricant does not enter the flow path.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 238]    238Cleaning or steam sterilizing:
 This subclass is indented under subclass 237.  Systems containing a means other than those causing or controlling the normal or unmodified flow of the fluent material of the system for removing germs or other undesirable internal or extraneous material from the system itself or parts thereof, as distinguished from treating the material being handled to remove undesirable material.

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15.04through 15.06, for a process of fluid cleaning a fluid handling system.
171+,for traps for separating or venting either gas or liquid from a pressure system containing both materials.
312+,for leakage or drip collecting in fluid handling devices.
387,for washing machine cycle control involving liquid level response or maintenance.
544+,for screens, filters, sediment, traps, etc., for removing undesired particles from the material being handled.

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8Bleaching and Dyeing; Fluid Treatment and Chemical Modification of Textiles and Fibers,   subclasses 137+ for cleaning and laundering processes for textiles and fibers. 147+ for manipulative fluid treatment processes for textiles and fibers.
15Brushing, Scrubbing, and General Cleaning,   appropriate subclasses for fluid blast or suction cleaning and mechanical cleaning with or without the addition of liquid.
62Refrigeration,   subclass 303 for a refrigerator combined with cleaning means.
68Textiles: Fluid Treating Apparatus,   appropriate subclasses for fabric cleaning by liquid contact.
134Cleaning and Liquid Contact With Solids,   appropriate subclasses for cleaning by liquid contact.
  
[List of Patents for class 137 subclass 239]    239Reverse fluid flow:
 This subclass is indented under subclass 238.  Systems in which the cleaning device includes a means for causing a fluid to flow in the reverse direction to the normal flow path to remove undesirable material from the system or parts thereof.

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102+,for reversing valves in supply and exhaust type self-regulating systems, especially subclasses 103+ for the suction pulsator type and 106 for 4-way valve systems.
207.5,for diverse fluid containing pressure systems having means to return fluid contained in the system to the source of supply.
249+,and 309+, for reversing valves of the regenerative furnace type.
627,for sequential distributing valves.
  
[List of Patents for class 137 subclass 240]    240With separate material addition:
 This subclass is indented under subclass 238.  Systems in which a separate material such as steam, air, water, valve grinding compounds or other chemical or physical agents are introduced into the fluent material of the system to clean parts of the system.

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255+,for systems having parallel discharge from plural tanks.
268,for systems with holders for solid, flaky or pulverized material to be dissolved or entrained, and see the search notes thereto.
602+,for systems having plural inflows and a single outflow, and see the search notes to subclass 602.

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222Dispensing,   subclasses 129+ for dispensers in which plural diverse fluids from plural sources are discharged either separately or together.
  
[List of Patents for class 137 subclass 241]    241Steam sterilizing:
 This subclass is indented under subclass 238.  Systems in which steam is used as a medium for cleaning germs or other infective agents from parts of the system.

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13,and 565+, for processes and systems using steam as a propelling fluid.
334+,for systems using influent gas or vapor for heating fluid.

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15Brushing, Scrubbing, and General Cleaning,   subclasses 316.1+ for cleaning by gas blast only.
  
[List of Patents for class 137 subclass 242]    242Mechanical cleaning:
 This subclass is indented under subclass 238.  Systems in which the undesired material is removed from the device or system or parts thereof by the physical interaction of two or more parts of the device or system, not including relations or operations which are part of or necessary for flow handling.
(1) Note. One or more of the interacting parts may be parts present solely for cleaning purposes, or all may have utility as flow handling means provided the two modes of operation are present.
(2) Note. This and the first indented subclass include disclosures relating to valve grinding only where the assembled system is described as having a specific nonvalving member or motion which produces valve grinding action or where the system or part when disassembled has a specific member that facilitates valve grinding.

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315.01through 329.4, for a fluid handling system with repair, tapping, or assembly means.
330+,for systems having nonvalving motion of the valve or valve seat for purposes other than cleaning or disassembling, though the motion may prevent fouling or dislodge material tending to settle on the valve parts.

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15Brushing, Scrubbing, and General Cleaning,   subclasses 104.31+ for sewer cleaners.
  
[List of Patents for class 137 subclass 243]    243Valve grinding motion of valve on seat:
 This subclass is indented under subclass 242.  Systems in which the fluent material system or a part thereof has means for giving the valve or its seat a motion which produces cleaning or grinding of the valve and/or its seat.
(1) Note. This motion must be one not contemplated or normally occurring in the fluid controlling movement of the valve.

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240,for this subject matter wherein a separate material (e.g., grinding compound) is added at the grinding zone.
330+,for other nonvalving motion of valves or valve seats.

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251Valves and Valve Actuation,   subclasses 215+ for plural motions of mechanically actuated valves.
451Abrading,   subclasses 115+ for grinding a valve on a seat by use of plural workholders, without an abrading tool.
  
[List of Patents for class 137 subclass 243.1]    243.1Concentric stem:
 This subclass is indented under subclass 243.  Devices in which the actuator is made up of an axial rod mounted within a sleeve.
  
[List of Patents for class 137 subclass 243.2]    243.2Spring pressed:
 This subclass is indented under subclass 243.  Devices provided with a spring which permits regrinding of the valve head on its seat.
  
[List of Patents for class 137 subclass 243.3]    243.3Lost motion permits grinding:
 This subclass is indented under subclass 243.  Devices provided with lost motion which permits the valve to rotate on its seat before it leaves the seat upon opening.

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243.2,for such connections which use a spring.
  
[List of Patents for class 137 subclass 243.4]    243.4With swivel-preventing means:
 This subclass is indented under subclass 243.  Devices in which a normally swiveled connection between the head and stem is blocked to cause the head to rotate on the seat as the stem rotates.
  
[List of Patents for class 137 subclass 243.5]    243.5Nut releasable from body and/or stem:
 This subclass is indented under subclass 243.  Devices comprising screw actuated valves in which the nut is disconnected from the body or the stem, or both, to permit the valve head to rotate without reciprocating.

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243.2,for valves in which a spring permits limited movement between the nut and the body or stem.
  
[List of Patents for class 137 subclass 243.6]    243.6With independent grinding actuator:
 This subclass is indented under subclass 243.  Devices which are provided with means in addition to and independent of the normal valve actuator for imparting the grinding motion to the valve.
  
[List of Patents for class 137 subclass 243.7]    243.7Separable:
 This subclass is indented under subclass 243.6.  Devices in which the grinding means is normally removed from the valve.
  
[List of Patents for class 137 subclass 244]    244Cleaning member reciprocates in passage:
 This subclass is indented under subclass 242.  Systems in which the fluent material system has a member which has a reciprocating movement to enter a restricted passage of the system to clean either or both parts, either the member, the passage or the movement being nonworking characteristics of the system; i.e., not contributing to the fluid flow causing or controlling function of the system, though the member or passage may be carried by a working part of the system.

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22Dispensing,   subclasses 149+ for dispensers in which a cleaning element enters the container outlet.
  
[List of Patents for class 137 subclass 245]    245By-pass cleaning:
 This subclass is indented under subclass 244.  Systems in which the reciprocating member cleans a branch channel.
(1) Note. The branch channel may comprise a diverting passage for fluid to be used to operate a valve, pilot valve, etc.

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599.01through 601.21, for systems dividing into parallel flow lines then recombining.
  
[List of Patents for class 137 subclass 245.5]    245.5Independent actuation:
 This subclass is indented under subclass 244.  Devices wherein the means to actuate the cleaning means is independent of the valve actuator.
  
[List of Patents for class 137 subclass 246]    246Liquid supplied at valve interface:
 This subclass is indented under subclass 237.  Systems in which a separate fluid is applied between the valve and its seats to seal the valve against passage of the fluent material carried by the system.
(1) Note. The sealing material may be a lubricant.

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15.06,for a process of cleaning using liquid on a valve or valve seat.
247+,for liquid valves and liquid trap seals.

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251Valves and Valve Actuation,   subclass 355 for lubrication in which the lubricant does not enter the flow path.
  
[List of Patents for class 137 subclass 246.11]    246.11Plural feed:
 This subclass is indented under subclass 246.  Valves wherein plural feed means (other than gravity) are provided for the sealing liquid to cause flow thereof.
  
[List of Patents for class 137 subclass 246.12]    246.12Line pressure feed:
 This subclass is indented under subclass 246.  Valves wherein line pressure is used to feed the sealing liquid.
  
[List of Patents for class 137 subclass 246.13]    246.13Feed by or with actuation:
 This subclass is indented under subclass 246.  Valves wherein the feed means is actuated by the valve actuator or is so interrelated therewith that feeding of sealing liquid is dependent on valve actuation.
  
[List of Patents for class 137 subclass 246.14]    246.14Loss control:
 This subclass is indented under subclass 246.  Valves having means to control or prevent the loss of sealing means to the line flow.
  
[List of Patents for class 137 subclass 246.15]    246.15Screw feed:
 This subclass is indented under subclass 246.  Valves having a screw means (e.g., screw fed plunger) for feeding the fluid.
  
[List of Patents for class 137 subclass 246.16]    246.16With check valve:
 This subclass is indented under subclass 246.15.  Valve having check valve means in the lubrication or sealing system.
  
[List of Patents for class 137 subclass 246.17]    246.17Excess relief:
 This subclass is indented under subclass 246.16.  Valves having means to permit escape of the sealing liquid from its flow system to prevent excessive pressure therein or as an indication of complete flow therein.
  
[List of Patents for class 137 subclass 246.18]    246.18Jacking:
 This subclass is indented under subclass 246.16.  Valves wherein the valve is lifted from its seat to aid actuation by the pressure of the lubricant.
  
[List of Patents for class 137 subclass 246.19]    246.19Jacking:
 This subclass is indented under subclass 246.15.  Valves wherein the lubrication pressure lifts the valve from its seat.

SEE OR SEARCH THIS CLASS, SUBCLASS:

246.18,for "jacking" with a check valve in the lubrication system.
  
[List of Patents for class 137 subclass 246.2]    246.2Seating:
 This subclass is indented under subclass 246.15.  Valves wherein the lubrication pressure aids in seating of the valve.
  
[List of Patents for class 137 subclass 246.21]    246.21Spring biased piston feed:
 This subclass is indented under subclass 246.  Valves wherein the lubricant feed means is a spring biased piston.
  
[List of Patents for class 137 subclass 246.22]    246.22External pressure:
 This subclass is indented under subclass 246.  Valves wherein the sealing material is introduced into the valve under pressure from some means such as a grease gun or oil pump.
  
[List of Patents for class 137 subclass 246.23]    246.23Gravity or capillary feed:
 This subclass is indented under subclass 246.  Valves wherein the lubricant flows by gravity or by capillarity.
  
[List of Patents for class 137 subclass 247]    247WITH LIQUID VALVES OR LIQUID TRAP SEALS:
 This subclass is indented under the class definition.  Apparatus in which a liquid, maintained at the desired location by some form of reservoir, is used as a seal or closure between adjacent parts of a system containing either a gas or a liquid which is lighter than the sealing liquid.

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138+,for periodic siphon discharge by release of trapped air through a liquid trap seal.
154+,for diverse fluid containing pressure systems, especially subclasses 154 and 172 for those containing plural liquids and 171+ for fluid separating traps and vents.
246+,for liquid sealing at the valve interface by supplying the sealing liquid to the flow path or directly to the valve interface.
505.31,and 505.4, for reactor surface of the inverted cup type having liquid seal.

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4Baths, Closets, Sinks, and Spittoons,   appropriate subclasses for liquid trap seals and valves combined with the subject matter of the class.
222Dispensing,   subclass 188 for fluid trap seals for dispenser inlets and outlets, including vents.
399Electrophotography,   subclasses 237+ for liquid developer applied to a latent image within an electrophotos:graphic device.
  
[List of Patents for class 137 subclass 247.11]    247.11Liquid seal in liquid flow line; flow liquid forms seal:
 This subclass is indented under subclass 247.  Apparatus comprising a U-shaped flow passage which retains a portion of a line flow liquid to provide a gas seal in the said line.

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138+,for periodic siphon discharge through liquid trap seals.
171+,for diverse fluid containing pressure systems with fluid separating traps, especially subclasses 177+ for a discriminating outlet for liquid.
216.1+,for a vented siphon breaking system including a liquid seal.
251,for seals utilizing a diverse liquid.

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210Liquid Purification or Separation,   appropriate subclasses for separation apparatus comprising liquid seals, particularly subclasses 163+ for grated inlet surface drains, subclasses 295+ for grated inlet catch basins, subclasses 116 and 119 for the same with a backflow preventing float or filtrate accumulation responsive valve, respectively, and subclasses 532.1+ for catch basins with gravitational separation.
  
[List of Patents for class 137 subclass 247.13]    247.13Valves:
 This subclass is indented under subclass 247.11.  Apparatus having a valve in the liquid flow line in or adjacent to the seal.
  
[List of Patents for class 137 subclass 247.15]    247.15Line condition change responsive:
 This subclass is indented under subclass 247.13.  Apparatus in which the valve is responsive to a change in the condition of the liquid in the flow line.

SEE OR SEARCH THIS CLASS, SUBCLASS:

386+,for liquid level responsive valves where no liquid seal is present, and particularly subclasses 409+ for float controlled valves.
455+,for other line condition change responsive valves.
  
[List of Patents for class 137 subclass 247.17]    247.17Plural valves or valve seats:
 This subclass is indented under subclass 247.15.  Apparatus having a plurality of line condition responsive valves or having such a valve which seats alternatively on one of a plurality of seats.

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512+,for plural direct response valves.
516.25,for check valves having serially arranged plural seats.
613+,for systems with plural serial valves in a single flow path.

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251Valves and Valve Actuation,   subclass 211 for a valve, per se, having serial alternately closed ports.
  
[List of Patents for class 137 subclass 247.19]    247.19Pivoted valve:
 This subclass is indented under subclass 247.15.  Apparatus in which the valve is pivoted.

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517+,for a biased opened direct response valve.
527+,for a pivoted check valve.
  
[List of Patents for class 137 subclass 247.21]    247.21Ball valve:
 This subclass is indented under subclass 247.15.  Apparatus in which the valve is a substantially spherical element.

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409+,especially subclasses 433 and 449 for float responsive ball valves.
519.5,for weight biases open direct response valves of the ball type.
533.11,for a weight biased ball check valve.
539+,for a spring biased ball check valve.
  
[List of Patents for class 137 subclass 247.23]    247.23Seats vertically up:
 This subclass is indented under subclass 247.21.  Apparatus having a seat lying in a general horizontal plane above the valve.

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519.5,for ball valves which are weight biased open.
  
[List of Patents for class 137 subclass 247.25]    247.25Seal replenishers:
 This subclass is indented under subclass 247.11.  Devices having (1) a distinct compartment with a restricted orifice which stores flow line liquid during flow and discharges it into the seal after the flow ceases in order to assure a seal or replace lost seal liquid, or (2) a connection to an outside source of seal liquid for the same purpose.

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114,and 118, for valves providing correlated flow in seal replenishing apparatus of the (2) type.
240,for means to add a cleaning material to a fluid handling system.
  
[List of Patents for class 137 subclass 247.27]    247.27Plural inlet:
 This subclass is indented under subclass 247.11.  Devices having connections for a plurality of inlet pipes.

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216.1+,for liquid seals with plural connections one of which is for an external vent means.
602+,for systems having multiple inlets and a single outlet, and see the search notes thereunder.
  
[List of Patents for class 137 subclass 247.29]    247.29Divided and recombined passages:
 This subclass is indented under subclass 247.11.  Devices having divided and recombined passage means for flow liquid and/or air, for preventing seal loss by forward siphonage.

SEE OR SEARCH THIS CLASS, SUBCLASS:

247.25,for divided and recombined passages where a seal replenishing chamber is included.
599.01through 601.21, for systems dividing into parallel flow lines then recombining.
  
[List of Patents for class 137 subclass 247.31]    247.31Tangential inlet flow:
 This subclass is indented under subclass 247.11.  Devices wherein the flow enters a leg of the U-shaped passage tangentially to the axis of the leg.
  
[List of Patents for class 137 subclass 247.33]    247.33Downward partition encircles projecting outlet:
 This subclass is indented under subclass 247.11.  Seals in which the U-shaped passage is formed by a chamber having a downwardly extending partition comprising an inverted cup and a distinct outlet pipe which projects up into the cup.

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210Liquid Purification or Separation,   subclasses 163+ and 247 for grated inlet surface drains with similar liquid seal means where the inverted cup functions as a filtrate splash plate or deflector.
  
[List of Patents for class 137 subclass 247.35]    247.35Submerged inlet pipe end:
 This subclass is indented under subclass 247.11.  Seals comprising a chamber having a distinct inlet pipe projecting thereinto and an outlet at a higher lever than the inlet pipe end opening.
  
[List of Patents for class 137 subclass 247.37]    247.37Hinged seal bowl:
 This subclass is indented under subclass 247.35.  Seals wherein the chamber comprises an overflow seal bowl hinged for movement into and out of seal forming position.
  
[List of Patents for class 137 subclass 247.39]    247.39Distinct seal bowl in flow line connected casing:
 This subclass is indented under subclass 247.35.  Seals wherein the chamber comprises a distinct overflow seal bowl within a flow line connected closed casing.

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210Liquid Purification or Separation,   subclass 247 for devices of similar structure including separation means.
  
[List of Patents for class 137 subclass 247.41]    247.41U-seals:
 This subclass is indented under subclass 247.11.  Seals wherein theU-shaped passage comprises a U-bend of which one leg thereof is an inlet pipe and constitutes the downflow column and the other leg is distinct and externally spaced from the first leg and constitutes the upflow column.
  
[List of Patents for class 137 subclass 247.43]    247.43Topside access beneath cover plate closed floor opening:
 This subclass is indented under subclass 247.41.  Apparatus installed beneath a surface and having a top side access means located beneath an opening in the surface, the opening being provided with a removable cover plate.
  
[List of Patents for class 137 subclass 247.45]    247.45Enlarged upflow leg:
 This subclass is indented under subclass 247.41.  Seals wherein the upflow leg or a portion thereof ahead of the overflow into the outlet is transversely larger than the downflow (inlet) leg.
  
[List of Patents for class 137 subclass 247.47]    247.47Topside access opening:
 This subclass is indented under subclass 247.45.  Seals with a top side access means located above the liquid seal level.

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247.43,for the same apparatus positioned beneath a surface, such as a floor, having a covered access opening therein.
  
[List of Patents for class 137 subclass 247.49]    247.49Even diameter legs:
 This subclass is indented under subclass 247.41.  Seals wherein both legs of the U-bend have substantially uniform and like internal cross sections.
  
[List of Patents for class 137 subclass 247.51]    247.51Access opening:
 This subclass is indented under subclass 247.49.  Seals having access means.

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138Pipes and Tubular Conduits,   subclass 92 for lateral plugs and closures.
  
[List of Patents for class 137 subclass 248]    248Seal for relatively movable valving parts:
 This subclass is indented under subclass 247.  Apparatus in which the liquid is used to seal a gap between relatively movable valving parts of a valve in at least one position of the valve, the liquid pool comprising in effect the seat for the movable valve element.

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246+,for liquid sealing at a valve interface where the liquid is supplied to seal the crack and is washed away when the valve is opened.
  
[List of Patents for class 137 subclass 249]    249Horizontally moving valve:
 This subclass is indented under subclass 248.  Apparatus in which the movement of the valve has a component in a horizontal plane.

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309+,for reversing valves of the regenerative furnace type which do not have a liquid seat.
  
[List of Patents for class 137 subclass 250]    250Rotary:
 This subclass is indented under subclass 249.  Apparatus in which the movement in a horizontal plane is rotary.

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311,for rotary reversing valves of the regenerative furnace type which do not have a liquid seat.
  
[List of Patents for class 137 subclass 251.1]    251.1Liquid valves:
 This subclass is indented under subclass 247.  Apparatus in which the sealing liquid alone performs a valving function in response to either external control means or to fluid pressure in the flow path, i.e., no flow conduit is withdrawn from the liquid to open a flow path.

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455+,for line condition responsive valve comprising solid material valve parts.

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222Dispensing,   subclass 188 for fluid trap seals for dispenser inlets and outlets, including vents.
  
[List of Patents for class 137 subclass 252]    252Branched passage for sealing liquid:
 This subclass is indented under subclass 251.1.  Apparatus in which at least one side of the liquid valve is provided with a branching path whereby as the sealing liquid rises on that side beyond a predetermined point it divides into a plurality of branches.

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472,for pop safety valves in which the top pressure reactor is in a branched released path.
  
[List of Patents for class 137 subclass 253]    253With auxiliary means for varying liquid level:
 This subclass is indented under subclass 251.1.  Apparatus including auxiliary means independent of the flow path for adjusting or varying the height of the liquid in the valve.
  
[List of Patents for class 137 subclass 254]    254With baffle:
 This subclass is indented under subclass 251.1.  Apparatus in which one or more baffles is provided either in or above the liquid of the valve, usually to restrict, deflect, or slow up sudden rising of the valving liquid.

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251Valves and Valve Actuation,   subclasses 118+ for devices having flow restrictors, especially subclass 127 for restrictors comprising baffles, and see the search notes to subclasses 118 and 127.
  
[List of Patents for class 137 subclass 255]    255PLURAL TANKS OR COMPARTMENTS WITH PARALLEL FLOW:
 This subclass is indented under the class definition.  Apparatus having two or more tanks or compartments so connected that (1) fluid from the same or different sources is separately supplied to different tanks or compartments, and/or (2) the tanks or compartments discharge separate fluid flows externally of the system or to parts of the system other than one another.

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87.01+,for self proportioning or correlating systems involving plural fluid sources.
124+,for plural siphons, especially subclass 127 for sequential parallel discharge from plural tanks.
208,for plural units in pressure systems having gas pressure stored over or displacing liquids.
571+,for plural tanks or compartments connected for series flow, i.e., discharging into one another, and see the search notes to subclass 571.

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222Dispensing,   subclasses 129+ for dispensers having plural sources, compartments and containers.
  
[List of Patents for class 137 subclass 256]    256Sequentially filled and emptied (e.g., holding type):
 This subclass is indented under subclass 255.  Apparatus having means for successively filling the tanks and means for subsequently emptying the filled tanks in succession. Many of the patents in this group of subclasses are directed to milk pasteurization tank systems, wherein milk at pasteurization temperatures is retained in a tank for a period of time before the tank is emptied.

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119.01+,for alternately substituted outlets of a line, as to plural tanks, in a self controlled system.
127,for siphon discharge of plural tanks in sequence.
160+,and 169+, for plural traps sequentially filled and emptied by gas pressure into a pressure chamber such as a boiler.
266+,for plural tanks discharging, receiving or vented through a manifold or through grouped outlets and 263 for similar devices in which the manifold is a tank.
627,for sequential distributor or collector type valve actuation.
  
[List of Patents for class 137 subclass 257]    257With relative rotation of tank group and filling head:
 This subclass is indented under subclass 256.  Apparatus in which a group of tanks or compartments and the filling means therefor are mounted for rotation with respect to one another.

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581,for movable tanks, and see the search notes thereto.

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141Fluent Material Handling, With Receiver or Receiver Coacting Means,