PATENTS   
Patents > Guidance, Tools, and Manuals >> Classification >>> Class Definition
    Class Numbers & Titles   | Class Numbers Only   | USPC Index   | International   | HELP  
You are viewing a Class definition.

 [Search a list of Patent Appplications for class 122]   CLASS 122,LIQUID HEATERS AND VAPORIZERS
Click here for a printable version of this file

SECTION I - CLASS DEFINITION

This class relates to heating liquids, generating vapors from liquids, treating the vapors generated for use, such as superheating or cooling them, and conserving the heat remaining in the liquid or vapor after a part of the heat energy has been made use of for any purpose. To bring a liquid heater into this class, the chamber, receptacle or conduit in which the liquid is heated must be fluid tight.

This class includes combinations of steam superheaters, feed-water heaters, steam separators, condensers, traps, manhole-closures, safety devices, cleaners, and feeders with a boiler when the structure of necessity must form a part of the boiler structure combination, also parts of boilers unless they are of general application.

This class includes water-cooled grates whether or not in connection with a boiler for heating the boiler water. It also includes the boiler and furnace in combination or the boiler alone with the furnace alone.

The liquid containers classified in this class may be heated by solid or fluid fuel burned in any type of furnace or burner, by friction, or by chemical action other than combustion, or by electricity. The heat may be applied directly to the walls of the fluid containing chamber or indirectly by the interposition of a fluid in a distinct and separate chamber, which fluid being heated may impart its heat to the fluid to be finally heated. When the fluid is heated by the interposition of another fluid the heat generator must be a part of the unitary structure of the fluid heater, with one exception--to wit: devices for generating a vapor having a vapor separator within the fluid chamber may be heated indirectly by a fluid, the furnace for heating which does not form part of the unitary structure. The fluid may be heated also by a heat radiating body in either a liquid, or solid state, which body may be either on the inside or on the outside of the fluid chamber; but if said heating body be inside the fluid chamber its nature must be such that it will not mix with the fluid to be heated.

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

The distinction between water heaters in Classes 122 and 126 is this: The water heaters in Class 122 have a closed water containing chamber or receptacle for holding the water while it is heated or have one or more closed conduits through which the water flows while being heated; but the water heaters in class 126 are of the open type. In Class 122 are classified mechanism for regulating both the inflow of water to the boiler and the burning of the fuel in all cases when steam is generated and also in all cases when water is heated, excepting in devices for heating water where the opening of a valve to permit water to flow through the heater at the same time increases the heat of the heat generator, such devices being classified in Class 126, subclasses 351; but this subclass relates only to the controlling device for the water and fuel. The structure of the water heater or boiler together with such a controlling mechanism are classified in Class 122.

SECTION III - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

15, Brushing, Scrubbing, and General Cleaning,   subclass 104.03 for pipe and tube cleaners generally 314, 316.1+ and 406+ for pipe and tube cleaners and boiler tube blowers using air or steam blast and/or suction.
29, Metal Working,   subclass 890.051 for a method of making a boiler or subclass 890.07 for a method of making a condenser, evaporator, or vaporizer.
60, Power Plants,   where combustion products are used as a motive fluid, subclasses 39.53 through 39.59including addition of steam or water, or subclass 775 including introducing water or steam; or subclasses 641.1-641.15 using natural heat (e.g., sun, air, water, earth, etc.).
68, Textiles: Fluid Treating Apparatus,   having significant structure for fluid treatment of a textile, subclass 15 for a textile fluid treating machine combined with a tank heater, or subclass 222 for an implement to apply steam to a textile.
73, Measuring and Testing,   subclasses 215+ for weir maters combined with feed water heater structures.
99, Foods and Beverages: Apparatus,   subclasses 276 , 277, and 359+ for beverages and food cookers using liquid heaters pertinent to this class; and subclasses 468+ for treatment of dairy food which includes milk treating apparatus using liquid heaters.
116, Signals and Indicators,   for signals.
126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclass 5 for a cooking and heating stove having a water heater or steam generator; subclasses 20-20.2 for a cooking oven heated by steam or hot water; subclass 31 for a cooking stove having a water heater in a flue extension; subclasses 34 and 35 for a cooking stove having a water back; subclass 101 for a hot air furnace combined with a boiler; subclasses 344-363.1 for a liquid heater that may include a kettle, a steam generator, stove pipe for use with a stove, and a domestic water heater or boiler (e.g., kitchen boiler, range boiler, etc.) for use with a stove or furnace; subclasses 513 and 514 for a fireplace with a liquid heater; subclasses 561-568 for a solar heat collector for a pond or pool; subclasses 569-713 for a solar heat collector that may include a fluid medium; or subclass 714 for a process of heating by using solar heat.
137, Fluid Handling,   subclass 11 for processes for regulating the boiler water level, subclass 94 for the control of the fuel in response to boiler or water heater condition subclasses 156+ for gas pressure discharge of liquid as to a boiler, subclasses 171+ for steam traps, subclasses 386+ for level responsive valves, and subclasses 557 and 558 for pressure and level responsive signals and indicators.
138, Pipes and Tubular Conduits,   appropriate subclasses for the wall structure of a boiler tube or flue; subclasses 89+ for plugs for pipes; and subclasses 98+ for patches for pipes.
165, Heat Exchange,   appropriate subclass, for a heat exchanger, per se.
202, Distillation: Apparatus,   subclasses 152+ for liquid volatilization for the purpose of recovering material from the vapor produced by condensation or absorption.
204, Chemistry: Electrical and Wave Energy,   subclasses 196.01 through 196.38for electrolytic protection apparatus (e.g., to prevent corrosion, scale formation, or other objectionable action upon liquid heaters or vaporizers, etc.).
205, Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions,   subclasses 724 through 740for processes of electrolytic protection of metal objects (e.g., to prevent corrosion, scale formation, or other objectionable action upon liquid heaters or vaporizers, etc.).
210, Liquid Purification or Separation,   subclasses 175+ for a heater or heat exchanger combined with liquid purification means.
219, Electric Heating,   subclasses 281+ for water heaters and steam generators particularly adapted to be heated by an electric heater.
220, Receptacles,   appropriate subclasses, for wall structures of containers of more general utility and for safety devices and for manhole covers.
237, Heating Systems,   for an apparatus or process of heating an enclosure, subclass 7 for a combined radiator and boiler having automatic control, or subclasses 16-18 for a combined boiler and radiator.
264, Plastic and Nonmetallic Article Shaping or Treating: Processes,   subclass 30 for furnace lining formation or repair and see the notes thereto.
411, Expanded, Threaded, Driven, Headed, Tool-Deformed, or Locked-Threaded Fastener,   subclass 367 for a threaded fastener and nut having stay bolt spacer sleeve; subclass 370 for a threaded fastener and nut having a stay bolt bearing washer; subclasses 379+ for a threaded stay bolt, per se; and subclass 505 for an unthreaded stay bolt, per se.
417, Pumps,   subclasses 36+ for liquid level control of a pump drive motor, subclasses 108+ for aerated column type pumps wherein is elevated by alternate globules of water and steam and subclasses 118+ for pumping of liquid by supplying or exhausting of gaseous motive fluid to or from a pump chamber.
451, Abrading,   for structural features of a cleaner for a tube or flue.
510, Cleaning Compositions for Solid Surfaces, Auxiliary Compositions Therefor, or Processes of Preparing the Compositions,   subclasses 247+ for compositions for descaling steam boilers or other water containers.

SECTION IV - GLOSSARY

BOILER

Used as a generic term for a liquid heater. The nature of the liquid heated is immaterial. Whether the liquid heated is conducted from the boiler as liquid or vapor depends upon the amount supplied and the degree of heat attained, and for this reason generally no distinction has been noted in the classification, similar structures being classified together regardless of the ultimate effect. In the type of boilers known as "flashers" this distinction is of importance and provision has been made therefor.

FIRE TUBES

Include both small and large tubes through which the products of combustion pass unless the term "flue" is used with them, in which case "fire tubes" would refer to the small tubes, and "flues" to the large tubes for the products of combustion.

STEAM

To be taken in a generic sense as meaning vapor.

STEAM TUBES

Designate vapor tubes whether the vapor therein be formed from water or any other liquid.

WATER TUBES

Designate tubes, both large and small, through which liquid or vapor passes.

WATER

To be taken in a generic sense as meaning liquid.

SUBCLASSES

[List of Patents for class 122 subclass 1]    1PLANTS:
 This subclass is indented under the class definition.  Combinations of elements and devices each performing different functions for the conservation of the heat generated in the furnace, the ultimate object of which is the production of steam or the heating of water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

21,for "alkali" steam generators.
448.1,449, 450, and 452, for regulating means.

SEE OR SEARCH CLASS:

60, Power Plants,   generally for devices peculiar to that class.
91, Motors: Expansible Chamber Type,   for plants involving the steam engine structure.
123, Internal-Combustion Engines,   subclasses 2+ for combinations of internal combustion motors and other engines and steam boilers.
237, Heating Systems,   subclasses 12.1 and 13 for vehicle plant and heating systems.
418, Rotary Expansible Chamber Devices,   for plants involving rotary expansible chamber structure.
  
[List of Patents for class 122 subclass 2]    2Garbage:
 This subclass is indented under subclass 1.  Plants for the destruction of garbage relating either to the arrangement of the boiler or the boiler structure adapted for this special purpose.

SEE OR SEARCH THIS CLASS, SUBCLASS:

232,and 376, for water grate structure adapted to burn garbage or other waste material.

SEE OR SEARCH CLASS:

110, Furnaces,   subclass 234 , for garbage plants with a conventional arrangement of a boiler therewith.
  
[List of Patents for class 122 subclass 3]    3Motor vehicle:
 This subclass is indented under subclass 1.  Boiler plants specially adapted for motor vehicles.

SEE OR SEARCH THIS CLASS, SUBCLASS:

446+,448.1, 449, and 452, for analogous structure.

SEE OR SEARCH CLASS:

60, Power Plants,   subclass 668 for a steam power system physically related to a vehicle.
180, Motor Vehicles,   subclasses 36+ for a motor vehicle of the steam traction engine type; subclasses 303+ for a motor vehicle having a traction motor of the kind which is driven by expansible gas from a source external of the motor and wherein the gas is produced by treating a volatile fluid (e.g., the gas is steam); and subclass 310 for a motor vehicle having means to generate steam for a propulsion purpose.
  
[List of Patents for class 122 subclass 4]    4MISCELLANEOUS:
 This subclass is indented under the class definition.  Boilers and parts thereof not otherwise classifiable.
  
[List of Patents for class 122 subclass 5]    5GAS-PRODUCER:
 This subclass is indented under the class definition.  Subject matter relating to combinations of a gas producing furnace and boiler when the structure of the boiler is intimately associated with the producer, so as to form a unitary structure, the gas from the producer being burned to heat the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

6+,for boilers heated by gas passing through a boiler from a gas producer, the heat of the hot gas being used for heating the boiler.

SEE OR SEARCH CLASS:

48, Gas: Heating and Illuminating,   for gas making plants including a boiler.
110, Furnaces,   subclass 229 for gas producer furnaces and see the notes therewith.
  
[List of Patents for class 122 subclass 5.51]    5.51AIR-INJECTED:
 This subclass is indented under the class definition.  Devices for vaporizing a liquid, with means for mingling air therewith in the vaporizer.
  
[List of Patents for class 122 subclass 5.52]    5.52Combustion gas and vapor contact:
 This subclass is indented under subclass 5.51.  Devices wherein the vapor is combined with the byproducts of burning fuels.
  
[List of Patents for class 122 subclass 6]    6INDUSTRIAL:
 This subclass is indented under the class definition.  Subject matter relating to boilers, water heaters, or cooling devices for furnace walls having a closed chamber or conduit combined with a conventional type of furnace employed in a special art.
(1) Note. If the cooling device is not a closed chamber or conduit, it will be classified in the type of furnace of the special art. Class 122 includes such devices known as bosh plates, water cooled walls and roofs, linings, and water cooled tuyeres when the cooling device is a closed chamber or conduit and there is otherwise no novelty in the invention.

SEE OR SEARCH CLASS:

48, Gas: Heating and Illuminating,   subclasses 63+ and 67, for gas producers using similar structure.
266, Metallurgical Apparatus,   subclasses 190 and 241 for cooling features in devices of that class.
431, Combustion,   subclass 160 for a furnace type combustion chamber having means directing nonliquid cooling medium across elements of a device dispersing fuel into a furnace.
432, Heating,   subclasses 233+ for a residual material heating apparatus element having protective cooling structure.
  
[List of Patents for class 122 subclass 6.5]    6.5Port:
 This subclass is indented under subclass 6.  Subject matter comprising water circulation devices applied to the gas or air ports of a furnace.

SEE OR SEARCH CLASS:

431, Combustion,   subclass 160 for a fuel disperser installed in a combustion chamber cooled by a gas additional to the combustion materials.
432, Heating,   subclass 173 for a specific furnace having a protective cooling means for combustion material feed structure.
  
[List of Patents for class 122 subclass 6.6]    6.6Tuyeres:
 This subclass is indented under subclass 6.  Subject matter comprising conduits for feeding air to furnaces and provided with a closed water-circulation.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 182.5+ for tuyeres of general application and for other water circulation means therefor.
266, Metallurgical Apparatus,   subclasses 265+ and especially 270 for tuyeres used in metallurgical apparatus which may include a liquid cooled tuyere element where the tuyere element is combined with additional structure, as for example, an external gas supply pipe, means for feeding diverse materials, flow control valves or a tuyere cooler, Further, see subclasses 186+ and 218+ for tuyeres combined with the treating vessel.
  
[List of Patents for class 122 subclass 6.7]    6.7Forge:
 This subclass is indented under subclass 6.6.  Devices with water circulation, of a type used in a forge and in which the direction of the air blast is usually vertical.

SEE OR SEARCH CLASS:

110, Furnaces,   subclass 182.6 for tuyeres in forge furnaces.
  
[List of Patents for class 122 subclass 7]    7Waste heat:
 This subclass is indented under subclass 6.  Devices comprising combinations of a conventional type of industrial furnace and a boiler located so as to be heated by the waste heat of the furnace.

SEE OR SEARCH THIS CLASS, SUBCLASS:

20,421 and 470, for analogous devices.

SEE OR SEARCH CLASS:

432, Heating,   subclasses 90+ for (1) a structure in which the waste heat of a nominal boiler heats a material heating chamber of the Class 432 type (2) a structure in which the waste heat of a specific furnace heats a closed water chamber or conduit or (3) for a residual combination of a liquid heater and a work heater of the Class 432 type in which the heated liquid is utilized in heating the work.
  
[List of Patents for class 122 subclass 8]    8Water firebox:
 This subclass is indented under subclass 6.  Industrial boilers having a water jacket firebox.
  
[List of Patents for class 122 subclass 9]    9Water tube type:
 This subclass is indented under subclass 8.  Industrial boilers including a firebox the walls of which are provided with water containing tubes.
  
[List of Patents for class 122 subclass 10]    10FOR FLUID FUEL BURNER:
 This subclass is indented under the class definition.  Boilers for generating steam for feeding a fluid fuel burner.

SEE OR SEARCH CLASS:

431, Combustion,   subclasses 207+ for a burner assembly including as an element a supply line in which burner feed; e.g., air, oil, or fuel atomizing water; is heated.
  
[List of Patents for class 122 subclass 11]    11ROTARY:
 This subclass is indented under the class definition.  Boilers in which a substantial part or the whole of the fluid-containing chamber is designed to be continuously-rotated while heating the water or generating steam.
  
[List of Patents for class 122 subclass 12]    12ROTATABLY SUPPORTED:
 This subclass is indented under the class definition.  Boilers that are supported in bearings so that the whole boiler or a substantial part thereof may be turned on an axis, generally either vertical or horizontal, after its connecting steam and water pipes have been uncoupled.
  
[List of Patents for class 122 subclass 13.01]    13.01STAND BOILER (E.G., WATER HEATER, ETC.):
 This subclass is indented under the class definition.  Subject matter comprising heating means applied directly or indirectly to the wall of the fluid containing chamber, where the fluid is water, to provide hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.).
(1) Note. The stand boiler (e.g., water heater, etc.) may be found in other than a house or home (e.g., apartment building, office building, restaurant, laundry, recreational vehicle, etc.) to provide hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.).

SEE OR SEARCH THIS CLASS, SUBCLASS:

20,for a subsidiary liquid heater consisting of a pipe, coil, hollow plate, or cylinder in a firebox, combustion chamber, or offtake flue of a furnace in a boiler to generate steam or hot liquid for other than the boiler.
233,for a horizontal disposed tank combined with a wall of a furnace.
234,for a vertically disposed tank combined with heating means.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclasses 350.1 through 350.2for a fluid fuel burner other than a top-accessible liquid heating vessel.
220, Receptacles,   subclass 567.3 for a stationary tank for a hot water heater or boiler.
392, Electric Resistance Heating Devices,   subclasses 322 and 323 for an electrically conductive fluid (e.g., water, etc.) forming part of the circuit that heats the fluid including a reservoir or tank, or subclasses 449-464 for a line-connected tank- or container-type liquid heater.
  
[List of Patents for class 122 subclass 13.3]    13.3And delivery means to dispensing feature:
 This subclass is indented under subclass 13.01.  Subject matter and means to convey the hot water from the stand boiler to some end use such as a domestic fixture (e.g., faucet, shower, washing machine, dishwasher, etc.).

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclass 362.1 for a boiler receiving hot liquid or steam from a stove or furnace (e.g., kitchen boiler, range boiler, etc.) having liquid circulation means, or subclass 365.1 for a liquid heater and stovepipe having liquid circulation means.
237, Heating Systems,   for an apparatus or process of heating an enclosure, subclass 7 for a combined radiator and boiler having automatic control or subclasses 16-18 for a combined boiler and radiator.
  
[List of Patents for class 122 subclass 14.1]    14.1And condition responsive feature:
 This subclass is indented under subclass 13.01.  Subject matter and means to sense a state or change in the state of the stand boiler or the water heated by the stand boiler to effect a change in the operation of the stand boiler or the heated water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

448.1through 448.4, for automatic control of fluid fuel and feed water to a boiler.
504through 507, for a boiler safety device.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclass 351.1 for a fluid fuel burner other than a top-accessible liquid heating vessel and a condition responsive feature or subclass 374.1 for an open-top liquid heating vessel that may include a lid and a condition responsive feature.
340, Communications: Electrical,   subclasses 500 through 693.12for an electrical automatic condition responsive indicating system.
  
[List of Patents for class 122 subclass 14.2]    14.2Controls burner:
 This subclass is indented under subclass 14.1.  Subject matter wherein the condition responsive feature effects change in the burner.

SEE OR SEARCH CLASS:

137, Fluid Handling,   subclass 94 for a condition responsive system where fuel is proportioned or correlated to some boiler or water system condition.
  
[List of Patents for class 122 subclass 14.21]    14.21By other than temperature of water:
 This subclass is indented under subclass 14.2.  Subject matter wherein the condition responsive feature controls the burner by other than responding to the condition of the water having a degree of hotness or coldness measured on a definite scale.
(1) Note. This may also include a temperature condition responsive means for the liquid.
  
[List of Patents for class 122 subclass 14.22]    14.22By temperature of water in water containing chamber or external tank:
 This subclass is indented under subclass 14.2.  Subject matter wherein the condition responsive feature controls the burner by responding to the condition of the water having a degree of hotness or coldness measured on a definite scale stored in the water containing chamber or a closed receptacle outside of and for storing water heated by the stand boiler.

SEE OR SEARCH CLASS:

374, Thermal Measuring and Testing,   subclasses 100 through 207for a temperature measuring device (e.g., thermometer, etc.).
  
[List of Patents for class 122 subclass 14.3]    14.3Having water flow control feature:
 This subclass is indented under subclass 14.1.  Subject matter wherein the condition responsive feature includes means to effect direction of movement or quantity of the water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

451.1,451.2, for a feed water heater having automatic control of the feed water flow by thermally responsive means.
456,457, for a feed water heater having a tank or receptacle that includes automatic control of inlet and outlet valves allowing the feed water to flow by gravity to the boiler.

SEE OR SEARCH CLASS:

137, Fluid Handling,   a residual class for process or apparatus, subclasses 87.01 through 87.06for a condition responsive system where fluid flow in a flow line is proportioned or correlated to some condition of a fluid flowing in another fluid flow line or subclasses 455-543.23 for a valve controlling a flow line responsive to a change in the condition of the fluid.
417, Pumps,   subclasses 279 through 311for a pump having condition responsive control of the pumped fluid.
  
[List of Patents for class 122 subclass 14.31]    14.31Using valve actuated by flow or pressure (e.g., check valve, etc.):
 This subclass is indented under subclass 14.3.  Subject matter wherein the water flow control feature is an element having a definite predetermined motion to open, close, or partially obstruct a port or passageway and is moved into action by the movement, quantity, or force per unit area of the liquid.

SEE OR SEARCH CLASS:

251, Valves and Valve Actuation,   subclasses 12 through 63.6for a valve actuated or retarded by fluid acting on the actuating means.
  
[List of Patents for class 122 subclass 15.1]    15.1Heated by liquid or steam (e.g., indirect heating, etc.):
 This subclass is indented under subclass 13.01.  Subject matter wherein the stand boiler uses a hot fluid that is shapeless, virtually incompressible, has a definite volume (e.g., water, etc.) or a vapor emitted from such a fluid to transfer thermal energy to the water in the stand boiler.
(1) Note. This may include a burner for heating the liquid or steam that transfers the thermal energy to the liquid in the stand boiler.
(2) Note. The heating liquid or steam may have a pressure higher than the liquid in the stand boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

32through 34, for a liquid indirectly heated by a separate heating fluid.
  
[List of Patents for class 122 subclass 16.1]    16.1Solid fuel burner:
 This subclass is indented under subclass 13.01.  Subject matter wherein the stand boiler is heated by the solid fuel burner.

SEE OR SEARCH THIS CLASS, SUBCLASS:

22,for a residual solid or liquid fueled boiler.
211,for a solid or liquid fueled sectional boiler.
368through 370, for a residual boiler having a water-jacketed firebox.

SEE OR SEARCH CLASS:

110, Furnaces,   a residual class for solid material combustion apparatus or a method of operating solid material combustion apparatus.
126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclasses 367.1 and 368.1 for a liquid heater having a solid fuel burner submerged underneath the surface of the liquid.
  
[List of Patents for class 122 subclass 17.1]    17.1Fluid fuel burner:
 This subclass is indented under subclass 13.01.  Stand boiler wherein the stand boiler is heated by the fluid fuel burner.

SEE OR SEARCH THIS CLASS, SUBCLASS:

23,for a residual boiler heated by fluid fuel.

SEE OR SEARCH CLASS:

431, Combustion,   for a residual process or apparatus of combustion or combustion starting.
  
[List of Patents for class 122 subclass 17.2]    17.2Liquid fuel burner:
 This subclass is indented under subclass 17.1.  Subject matter wherein the fluid fuel is shapeless, virtually incompressible, and has a definite volume.
  
[List of Patents for class 122 subclass 18.1]    18.1Having heat exchange feature:
 This subclass is indented under subclass 17.1.  Subject matter wherein the stand boiler includes means to transfer heat from the burned fuel directly or through the interposing fluid to the wall of the water containing chamber without allowing them to mix.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclasses 376.1 through 391.1for an open-top liquid heating vessel that may include a lid having a heating fluid confining, directing, or shielding feature; or subclass 390.1 for an open-top liquid heating vessel that may include a lid having a heating wall structure.
165, Heat Exchange,   for a residual heat transfer apparatus or process.
  
[List of Patents for class 122 subclass 18.2]    18.2Preheater:
 This subclass is indented under subclass 18.1.  Subject matter wherein the heat exchange feature is used to transfer heat, usually waste heat, to a fluid (e.g., air, liquid, water, etc.) before it is heated by the stand boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

412through 444, for a feed water heater.

SEE OR SEARCH CLASS:

431, Combustion,   for a residual process or apparatus of combustion or combustion starting, subclasses 207 through 248for a heated fuel line section that feeds a burner.
  
[List of Patents for class 122 subclass 18.3]    18.3Fire tube or flue surrounded by water containing chamber:
 This subclass is indented under subclass 18.1.  Subject matter wherein the heat exchange feature consists of the fire tube or flue enclosed on all sides by the water containing chamber.

SEE OR SEARCH THIS CLASS, SUBCLASS:

44.1through 45, for a residual boiler having a fire tube.
135.1through 156, for a boiler having a large fire tube or flue wholly or partly surrounded by the water space.
  
[List of Patents for class 122 subclass 18.31]    18.31Penetrates one side of water chamber to another:
 This subclass is indented under subclass 18.3.  Subject matter wherein the fire tube or flue passes through a wall of the water chamber to an opposing wall.
  
[List of Patents for class 122 subclass 18.4]    18.4Water tube surrounded by burned fuel:
 This subclass is indented under subclass 18.1.  Subject matter wherein the heat exchange feature consists of the water tube enclosed on all sides by the burned fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

235.11through 365, for a boiler having a water tube through which the water circulates or passes while being heated.
  
[List of Patents for class 122 subclass 18.5]    18.5And external water tank:
 This subclass is indented under subclass 17.1.  Subject matter and a closed receptacle outside of and for storing water heated by the stand boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

19.2,for a stand boiler (e.g., water heater, etc.) that provides hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.) that may be in other than a house or home (e.g., apartment building, office building, restaurant, laundry, recreational vehicle, etc.) and a casing for the stand boiler or an external tank therefor.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclasses 361.1 through 363.1for a boiler receiving hot liquid or steam from a stove or furnace (e.g., kitchen boiler, range boiler, etc.).
  
[List of Patents for class 122 subclass 19.1]    19.1Water containing chamber or external tank having circulation feature within:
 This subclass is indented under subclass 13.01.  Subject matter wherein the water containing chamber or a closed receptacle outside of and for storing water heated by the stand boiler having means inside to direct the movement or development of the water.
(1) Note. This may include means to create (e.g., inlet, outlet, mixer, etc.) or prevent (e.g., baffle, dampener, diffuser, etc.) circulation within the water chamber.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclass 362.1 for a boiler receiving hot liquid or steam from a stove or furnace (e.g., kitchen boiler, range boiler, etc.) having liquid circulation means or subclass 365.1 for a liquid heating stovepipe having liquid circulation means.
392, Electric Resistance Heating Devices,   subclass 452 for a line connected tank or container type liquid heater having an immersion heating element and a baffle or guard to direct the liquid.
  
[List of Patents for class 122 subclass 19.2]    19.2And casing feature for stand boiler or external water tank therefor:
 This subclass is indented under subclass 13.01.  Subject matter and covering, jacketing, or sheathing means for the stand boiler or a closed receptacle outside of and for storing water heated by the stand boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

18.5,for a stand boiler (e.g., water heater, etc.) that provides hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.) that may be in other than a house or home (e.g., apartment building, office building, restaurant, laundry, recreational vehicle, etc.) having a fluid fueled burner and an external liquid tank.
494,for a miscellaneous casing surrounding a boiler.

SEE OR SEARCH CLASS:

29, Metal Working,   subclass 455.1 for a method of assembling or joining a spaced wall tube or receptacle.
220, Receptacles,   subclasses 592.22 and 592.23 for a thermally insulated receptacle for heated contents (e.g., fireless cooker, etc.) or subclass 694.1 for an external covering for a hot water heater or boiler.
312, Supports: Cabinet Structure,   subclass 236 for a cabinet structure intended for heating, cooling, or heat exchange means.
  
[List of Patents for class 122 subclass 20]    20SUBSIDIARY:
 This subclass is indented under the class definition.  Steam generators or water heaters located either in the firebox, combustion chamber, or offtake flue of a furnace whose main purpose is not for the generation of steam or the heating of water in such boiler. These boilers may be of any form consisting of mere pipes or coils, hollow plates, or cylinders with or without fire flues or tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

6+,10, 37, 38, 439, and 498, for analogous structure.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclass 5 for a cooking and heating stove having a water heater or steam generator, subclass 31 for a cooking stove having a water heater in a flue extension, subclass 34 for a cooking stove having a water back, subclass 101 for a hot air furnace combined with a boiler, subclasses 364.1 and 365.1 for a liquid heater stovepipe, or subclasses 513 and 514 for a fireplace with a liquid heater.
  
[List of Patents for class 122 subclass 21]    21CHEMICAL:
 This subclass is indented under the class definition.  Boilers wholly or partly heated by chemical action other than that of the combustion of fuel. This subclass includes that type of liquid heater and steam generator known in the art as "alkali" generators for steam.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   subclasses 263.01+ for chemical heaters of general utility.
  
[List of Patents for class 122 subclass 22]    22FLUID AND SOLID FUEL:
 This subclass is indented under the class definition.  Boilers not otherwise classifiable heated by solid or fluid fuel or both combined.

SEE OR SEARCH THIS CLASS, SUBCLASS:

16.1,for a stand boiler (e.g., water heater, etc.) that provides hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.) that may be in other than a house or home (e.g., apartment building, office building, restaurant, laundry, recreational vehicle, etc.) having a solid fuel burner.
211,for sectional boilers heated by solid or fluid fuel.
  
[List of Patents for class 122 subclass 23]    23FLUID FUEL:
 This subclass is indented under the class definition.  Boilers not otherwise classifiable that are heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

10,for a boiler that generates steam to feed a fluid fuel burner.
17.1through 18.5, for a stand boiler (e.g., water heater, etc.) that provides hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.) that may be in other than a house or home (e.g., apartment building, office building, restaurant, laundry, recreational vehicle, etc.) having a fluid fuel burner.
41,for a fluid fueled flash boiler.
43,for a residual fluid fuel boiler having fire and water tubes.
45,for a fluid fueled boiler having a fire tube.
115,for a fluid fueled boiler having a vertically positioned fire tube.
156,for a fluid fueled boiler having a vertically positioned flue.
161,for a fluid fueled boiler having a vertically positioned flue surrounded by a concentrically spaced water shell.
167,for a fluid fueled boiler having a vertically positioned flue where a water tube is within the flue.
177,for a fluid fueled boiler having a vertically positioned flue where a water tube is within and extends transversely across the flue.
179,for a fluid fueled boiler having a vertically positioned flue where a water tube is within the flue and a small fire tube is in alinement with the flue.
183,for a fluid fueled boiler having a vertically positioned flue and a spiral water conduit.
208,for a boiler having a flat plate provided with a zigzag passage heated by a fluid fuel burner.
210,for a sectional boiler heated by a fluid fuel burner.
211,for a sectional boiler able to use either a fluid or solid fuel.
216,for a fluid fueled boiler formed of superimposed horizontal sections that are in fluid communication with each other at their centers.
236,for a fluid fueled boiler having a water tube through which the water circulates or passes while being heated.
243,for a fluid fueled boiler having a tube passage that has an extremely small cross-sectional area as compared with its length.
245,for a fluid fueled boiler having a vertical stand pipe around which extends a tubular coil or loop in direct or indirect fluid communication with the stand pipe.
248,for a fluid fueled boiler having a horizontally coiled water tube.
250,for a fluid fueled boiler having a vertically coiled water tube.
274,for a fluid fueled boiler having a water tube in fluid communication with a longitudinal upper drum.
283,for a fluid fueled boiler having a water tube looped vertically over the firebox.
308,for a fluid fueled boiler having a central stand pipe water tube and a radially projecting spur tube.
319,for a fluid fueled boiler having a vertical spur water tube.
322,for a residual fluid fueled boiler having a standpipe provided with a water tube.
328,for a fluid fueled boiler having a single upper drum, plural lower drums, and water tubes that straddle the combustion chamber.
333,for a fluid fueled boiler having a vertical water tube.
348,for a fluid fueled boiler having a water tube provided with an internal fire tube.
356,for a fluid fueled boiler having a water tube where the water zigzags through the tube.
446,447, for a boiler using other than automatic means to regulate fluid fuel to a burner and water to the boiler.
  
[List of Patents for class 122 subclass 24]    24Explosion:
 This subclass is indented under subclass 23.  Devices the fuel combustion of which is intermittent and explosive.

SEE OR SEARCH CLASS:

60, Power Plants,   where combustion products are used as a motive fluid, subclasses 722 through 39.828having a combustion products generator or subclasses 784-785 for nominal other than power plant output feature.
  
[List of Patents for class 122 subclass 25]    25Superimposed:
 This subclass is indented under subclass 23.  Devices provided with a plurality of fluid fuel burners one above the other.
  
[List of Patents for class 122 subclass 26]    26FRICTION GENERATOR:
 This subclass is indented under the class definition.  Boilers heated by friction.

SEE OR SEARCH THIS CLASS, SUBCLASS:

380,for boilers having mechanically operated cleaning agitators.
411,for mechanical circulating devices.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   subclass 247 for other frictional heaters.
  
[List of Patents for class 122 subclass 27]    27Surface:
 This subclass is indented under the class definition.  Boilers heated by a noncombustible hot material, such as slag, bars, or pigs of iron, or brick that does not come into contact with the liquid to be heated.
  
[List of Patents for class 122 subclass 28]    28Water in contact:
 This subclass is indented under the class definition.  Boilers heated by a noncombustible hot material, either introduced into the water or having the water fed upon the hot material.

SEE OR SEARCH THIS CLASS, SUBCLASS:

31.1,for fluid heated by injection of a hot fluid.
  
[List of Patents for class 122 subclass 29]    29ANNULAR FIREBOX:
 This subclass is indented under the class definition.  Boilers not otherwise classifiable which have an annular firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

127,184, 246, 309, 323, and 335, for other boilers with an annular firebox.
  
[List of Patents for class 122 subclass 30]    30MAGAZINE:
 This subclass is indented under the class definition.  Boilers having fuel magazines and not otherwise classifiable.

SEE OR SEARCH THIS CLASS, SUBCLASS:

5,46, 66, 92, 117, 124, 128, 136, 157, 158, 162, 168, 212, 219, 222, 237, 251, 272, 310, 320, 334, 339, 344, and 373, for other boilers having fuel magazines.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 293+ and the notes thereunder for other fuel magazines.
  
[List of Patents for class 122 subclass 31.1]    31.1INDIRECTLY HEATED SEPARATE INJECTED FLUID:
 This subclass is indented under the class definition.  Devices in which heating of a fluid is by the injection of a hot fluid.

SEE OR SEARCH THIS CLASS, SUBCLASS:

28,for analogous devices used for noncombustible hot material.
  
[List of Patents for class 122 subclass 31.2]    31.2Submerged flame:
 This subclass is indented under subclass 31.1.  Devices wherein the hot fluid is produced by an underwater combustion.
  
[List of Patents for class 122 subclass 32]    32Surface:
 This subclass is indented under the class definition.  Devices having two separate compartments not in communication, the liquid to be vaporized being in one compartment and heated by a hot fluid in the other compartment.
(1) Note. Slag heated boilers, where the slag heats a fluid like air or water which in turn imparts its heat to the water in the steam making chamber and water evaporating apparatus indirectly heated, provided the structure of such apparatus must act as a vapor or steam generator, are classified in this and its subsidiary subclasses. Even sugar evaporators and vacuum pans are classified here if the structure is such as to be of general application as a steam generator and the discharge outlet for the syrup is only of such a character as to be equally adapted for a blow-off conduit for sludge in a steam generator.

SEE OR SEARCH THIS CLASS, SUBCLASS:

483,for superheaters indirectly heated.

SEE OR SEARCH CLASS:

62, Refrigeration,   subclass 45.1 for process and apparatus for vaporizing liquefied gas requiring steps or means involving pressure or temperature control special to liquefied gas and more than required for other liquids.
165, Heat Exchange,   appropriate subclasses for a heat exchanger having two noncommunicating chambers not having a vapor separator in a heated chamber.
210, Liquid Purification or Separation,   subclasses 175+ for a heater combined with apparatus of that (210) class.
  
[List of Patents for class 122 subclass 33]    33Furnace:
 This subclass is indented under subclass 32.  Devices, provided with a furnace forming a part of the unitary structure.
  
[List of Patents for class 122 subclass 34]    34Separator:
 This subclass is indented under subclass 32.  Devices having an internal vapor or steam separator.
  
[List of Patents for class 122 subclass 35]    35ACCUMULATOR:
 This subclass is indented under the class definition.  Boilers provided with one or more chambers in which the hot boiler water or steam may be stored when less than the normal amount of steam is being used, which may serve as a storage reservoir for heat energy under abnormal demands for steam.

SEE OR SEARCH CLASS:

60, Power Plants,   subclass 659 for a heat operated power system including a heat steam or compressed gas storage means.
  
[List of Patents for class 122 subclass 36]    36AUXILIARY STEAM HEATER:
 This subclass is indented under the class definition.  Boilers having means for passing exhaust steam through conduits within the boiler or in surface contact therewith or for passing live steam generated in the same boiler or in another boiler into the water in the boiler. This subclass includes processes for getting up steam by the injection of live steam from one boiler into another boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

27,and 28, for boilers heated by slag or hot brick or bars of iron.
31.1,for boilers heated by the injection of a liquid of a kind that does not mix with the water in the boiler.
32+,for boilers heated indirectly by another hot fluid.
407,for injector circulation systems.
463,for similar structure in steam treating superheaters.
509,for submerged chambers.
  
[List of Patents for class 122 subclass 37]    37COMPARTMENT:
 This subclass is indented under the class definition.  Boilers having separate water chambers, which may or may not be in communication with each other at the top of the boiler. Theses boilers are designed to be used either as steam boilers for generating steam at different pressure or for generating steam and also for heating water when it is desired to have steam for one purpose and water heating for other purposes, as for instance, using the steam for one set of radiators and the water for another set, or for generating steam or hot water for the radiators on one floor of a building and for generating steam or hot water for radiators on another floor, with separate circuits to each compartment.

SEE OR SEARCH THIS CLASS, SUBCLASS:

20,for boilers provided with auxiliary water heaters, where the water is heated or steam generated for separate use.
33,for boilers having separate compartments, where the water is heated or steam generated indirectly by heat from water or steam heated in another compartment of the boiler by a furnace.
83,and 123, for boilers with separate compartments, where the water is fed progressively from one compartment to the next one.
125,420, 421, and 439, for water heaters heated by furnace gases.
  
[List of Patents for class 122 subclass 38]    38Draft regulator:
 This subclass is indented under subclass 37.  Devices at least one compartment being for heating water to operate a motor for regulating the combustion of the boiler furnace.
  
[List of Patents for class 122 subclass 39]    39FILM:
 This subclass is indented under the class definition.  Boilers in which the liquid flows over the heating surface of the boiler in a thin stream and occupies only a limited portion of the boiler space.

SEE OR SEARCH THIS CLASS, SUBCLASS:

218,and 242+, for capillary tubes.
258,for allied art.
501+,for displacing elements in tubes causing the liquid to spread in a thin film.

SEE OR SEARCH CLASS:

126, Stoves and Furnaces,   for a water heater or steam generator of an open or unpressurized type, or may be a closed or pressurized type if it is part of the stove or furnace structure, subclass 359.1 for a fluid fuel burner other than a top-accessible liquid heating vessel where the liquid flows down a cylindrical or conical surface.
  
[List of Patents for class 122 subclass 40]    40FLASHER:
 This subclass is indented under the class definition.  Boilers in which liquid is flashed into vapor as soon as it enters the vapor generating chamber. The liquid may be preheated in a chamber forming part of the unitary boiler structure or preheated in a chamber separate from the main vapor generator.

SEE OR SEARCH THIS CLASS, SUBCLASS:

39,242+ and 260, for progressive heaters.
247+,for progressively heated steam generators.
446,448.1, 449, and 452, for regulating devices for flashers and progressively heated steam generators.

SEE OR SEARCH CLASS:

60, Power Plants,   where combustion products are used as a motive fluid subclass 39.3 combined with automatic regulation of power output feature using water or steam, subclasses 39.53-39.59 including addition of steam or water, or subclass 775 for a process of introducing water or steam.
219, Electric Heating,   subclasses 271+ for electrically heated flash boilers.
  
[List of Patents for class 122 subclass 41]    41Fluid fuel:
 This subclass is indented under subclass 40.  Flash boilers heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

39,248 and 250, for progressively heated fluid by a fluid fuel burner.
446,448.1 and 452, for regulation of boilers.
  
[List of Patents for class 122 subclass 42]    42FIRE AND WATER TUBE:
 This subclass is indented under the class definition.  Boilers provided with both water tubes and fire tubes not otherwise provided for.

SEE OR SEARCH THIS CLASS, SUBCLASS:

53+,68+ and 98, for horizontal fire tube boilers with water tubes.
113,for analogous art.
130+,for vertical fire tube boilers provided with water tubes.
138,140+, 149+, and 152, for horizontal flue boilers with water tubes.
153+,and 166+, for vertical flue boilers provided with water tubes.
195+,for horizontal cylindrical boilers with water tubes.
  
[List of Patents for class 122 subclass 43]    43Fluid fuel:
 This subclass is indented under subclass 42.  Devices heated by fluid fuel.
  
[List of Patents for class 122 subclass 44.1]    44.1FIRE TUBE:
 This subclass is indented under the class definition.  Boilers having fire tubes not otherwise classifiable.
(1) Note. The term "fire tube" is used in a sense broad enough to include both small tubes and large tubes forming passages through a chamber when the size of the tube is immaterial to the invention claimed; but patents disclosing boilers provided with large fire tubes or "flues", where the large size of the tubes is a material feature of the structure and is necessary to the structure of the boiler and its combination with other features, are classified under the "flue" types of boilers, subclass 135, and the subclasses thereunder, except in that type of boiler where the large fire tube or flue be a subsidiary feature of the boiler, which is manifestly of the small fire tube type, in which case it is classified under the fire tube subclasses. See for example, this class, subclasses 47, 48, 50, and 78.
(2) Note. When a large flue in a boiler is essential to the structure and is not a mere subsidiary feature, such patents are classified in the "flue" type of boiler, although small fire tubes are an essential part of the combination, except those type classified in this class, subclasses 47 and 48.

SEE OR SEARCH THIS CLASS, SUBCLASS:

37,for boilers having separate compartments having fire tubes.
42+,for miscellaneous combinations of fire tube and water tube boilers, but only those that are not specially provided for in the combination fire tube and water tube subclasses under the fire tube or the flue type.
191,through 207, inclusive, under horizontal cylinder, for horizontal cylindrical boilers having water heating structures consisting of water tubes, drums, water walls, and water chambers of various forms, in combination with the boiler or being of such a configuration as to adapt it for use with a horizontal cylindrical boiler provided fire tubes are not essential to the boiler.
  
[List of Patents for class 122 subclass 44.2]    44.2With baffle in flue:
 This subclass is indented under subclass 44.1.  Devices wherein a static structure regulates the fluid flow in a flue.
  
[List of Patents for class 122 subclass 45]    45Fluid fuel:
 This subclass is indented under subclass 44.  Fire tube boilers heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

115,156, 161, 167, 179, and 183, for other fire tube or flue boilers heated by fluid fuel.
  
[List of Patents for class 122 subclass 46]    46Magazine:
 This subclass is indented under subclass 44.  Fire tube boilers having a fuel magazine.

SEE OR SEARCH THIS CLASS, SUBCLASS:

92,117, 124, and 128, for other fire tube boilers with magazines.
157,162 and 168, for other flue boilers with magazines.
212,219 and 222, for sectional boilers with fuel magazines.
  
[List of Patents for class 122 subclass 47]    47Horizontal:
 This subclass is indented under subclass 44.  Devices having a large horizontal flue, not covered by the definitions of other subclasses.

SEE OR SEARCH THIS CLASS, SUBCLASS:

50,and 78, for analogous art.
136,for horizontal flue boilers with transverse fire tubes.
149,for horizontal flue boilers with return fire tubes within the same part of the boiler as the flue.
  
[List of Patents for class 122 subclass 48]    48Vertical:
 This subclass is indented under subclass 44.  Devices having a large vertical flue not covered by the definitions of other subclasses.

SEE OR SEARCH THIS CLASS, SUBCLASS:

49,and 114+, for other vertical fire tubes.
  
[List of Patents for class 122 subclass 49]    49Horizontal and vertical:
 This subclass is indented under subclass 44.  Fire tube boilers having both horizontal and vertical fire tubes.
  
[List of Patents for class 122 subclass 50]    50Flue:
 This subclass is indented under subclass 44.  Fire tube boilers that are horizontal or somewhat inclined from the horizontal having fire tubes that communicate with a large flue within the boiler, that may serve as a firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

78,80, 95, and 149, for special features.
109,for inclined fire tube boilers.
  
[List of Patents for class 122 subclass 51]    51Horizontal:
 This subclass is indented under subclass 44.  Devices comprising fire tube boilers that are horizontal not covered by other subclasses.

SEE OR SEARCH THIS CLASS, SUBCLASS:

47,for fire tube boilers with a large horizontal flue.
49,for horizontal fire tube boilers having vertical fire tubes.
113,for horizontal boilers with transverse fire tubes.
136+,for combinations of horizontal large flue boilers with fire tubes, both horizontal and vertical.
  
[List of Patents for class 122 subclass 52]    52Plural:
 This subclass is indented under subclass 51.  Devices having two or more boilers arranged side by side or superposed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

82,and 137, for horizontal flue boilers with the same arrangement.
  
[List of Patents for class 122 subclass 53]    53Water tube:
 This subclass is indented under subclass 52.  Devices with water tubes in various arrangement.

SEE OR SEARCH THIS CLASS, SUBCLASS:

138,for horizontal flue boilers with water tubes.
  
[List of Patents for class 122 subclass 54]    54Double outlet:
 This subclass is indented under subclass 51.  Devices with a firebox located midway its ends, having outlets for the products of combustion opposite each other.
  
[List of Patents for class 122 subclass 55]    55Cylinder:
 This subclass is indented under subclass 51.  Subject matter relating to the structure of single cylindrical boilers.
(1) Note. The Horizontal cylindrical subclasses for the boiler features without the fire tubes.
  
[List of Patents for class 122 subclass 56]    56Rear of bridge wall:
 This subclass is indented under subclass 51.  Devices having a separate and distinct boiler section provided with fire tubes, located beneath the boiler, at the rear of the bridge wall.

SEE OR SEARCH THIS CLASS, SUBCLASS:

81,85+, 110, and 191, for closely allied art.
  
[List of Patents for class 122 subclass 57]    57Alternate smoke return:
 This subclass is indented under subclass 51.  Devices having a two-part water firebox or the equivalent thereof, with mechanism for passing the products of combustion from one part of the firebox to the other part, in order that the smoke may be consumed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

60,for similar functions with a different structure.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 208+ for similar art.
  
[List of Patents for class 122 subclass 58]    58Drop water firebox:
 This subclass is indented under subclass 51.  Devices having a water firebox united to and extending below the main body of the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

73,74 and 76+, for return fire tube horizontal fire tube boilers with drop water fireboxes.
107,for horizontal fire tube boilers with water walls having a drop water firebox.
139,141 and 146, for horizontal large flue boilers with drop water fireboxes.
  
[List of Patents for class 122 subclass 59]    59Circulation conduit:
 This subclass is indented under subclass 58.  Devices with a conduit located either inside or outside the boiler to connect the water firebox with the opposite end of the boiler to help the circulation of the water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

91,for water conduits provided with a sediment trap and water heating tubes.
  
[List of Patents for class 122 subclass 60]    60Alternate smoke return:
 This subclass is indented under subclass 58.  Devices made with two compartments, with means for alternately passing the products of combustion from one compartment to the other.

SEE OR SEARCH THIS CLASS, SUBCLASS:

57,for water fireboxes with alternate smoke return features.
95,for plural fireboxes.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 208+ for similar functions in the furnace art.
  
[List of Patents for class 122 subclass 61]    61Drop water baffle:
 This subclass is indented under subclass 58.  Devices with a water baffle depending from the top of the firebox, formed either by walls spaced apart or water tubes, or water tubes combined with fire brick, or water walls.

SEE OR SEARCH THIS CLASS, SUBCLASS:

188,for analogous art.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 324+ for similar art.
  
[List of Patents for class 122 subclass 62]    62Front and rear water baffle:
 This subclass is indented under subclass 58.  Devices with both front and rear water baffles for the products of combustion.

SEE OR SEARCH THIS CLASS, SUBCLASS:

71,for rear baffles having water tubes on which rests brickwork.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 322+ , 331+ and 336+ for similar functions in the combustion art.
  
[List of Patents for class 122 subclass 63]    63Front water baffle:
 This subclass is indented under subclass 58.  Devices with a water baffle in the front of the firebox.
  
[List of Patents for class 122 subclass 64]    64Interposed combustion chamber:
 This subclass is indented under subclass 58.  Devices with a separate combustion chamber between the firebox and the fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

95,and 100, for other types of boilers with an interposed combustion chamber between the firebox and the fire tubes.
  
[List of Patents for class 122 subclass 65]    65Rear water baffle:
 This subclass is indented under subclass 58.  Devices, with a water baffle in the rear of the firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

62,for analogous art.
71,for solid baffles, supported by water tubes.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 331+ and 336+ for similar art.
  
[List of Patents for class 122 subclass 66]    66Water coking chamber:
 This subclass is indented under subclass 58.  Devices containing a water-cooled coking chamber for fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

67,and 92, for analogous art.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 230+ for similar art.
  
[List of Patents for class 122 subclass 67]    67Intermediate draft:
 This subclass is indented under subclass 58.  Devices with a plurality of fuel chambers, one of which at least has a water grate, the products of combustion from the fuel chambers meeting each other. The fuel chambers are generally superposed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

66,for boilers of this type when the upper fuel chamber is a coking chamber.
371+,for grate structure.
  
[List of Patents for class 122 subclass 68]    68Water tube:
 This subclass is indented under subclass 58.  Devices with some form of water chamber, conduits or tubes in the firebox.
  
[List of Patents for class 122 subclass 69]    69Check-valved:
 This subclass is indented under subclass 68.  Devices with check valves so arranged that water from the boiler circulates through the chambers, conduits or tubes until feed water is being fed thereto, when the boiler circulation is cut off.

SEE OR SEARCH THIS CLASS, SUBCLASS:

118,for similar art.
196,for check valved feed heaters for horizontal cylindrical boilers.
  
[List of Patents for class 122 subclass 70]    70Feeding air:
 This subclass is indented under subclass 68.  Devices with air feeding conduits.
  
[List of Patents for class 122 subclass 71]    71Solid baffle:
 This subclass is indented under subclass 68.  Devices with solid baffle brick combined with the tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

61,65, 68, and 69, for analogous art.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 324+ for similar art disclosed.
  
[List of Patents for class 122 subclass 72]    72Projecting into firebox:
 This subclass is indented under subclass 51.  Devices having the end of the boiler projecting into the firebox or overhanging the fire grate.
  
[List of Patents for class 122 subclass 73]    73Drop water firebox:
 This subclass is indented under subclass 72.  Devices projecting into a drop water firebox.
  
[List of Patents for class 122 subclass 74]    74Drop water firebox:
 This subclass is indented under subclass 51.  Devices having a drop water firebox so arranged that the products of combustion pass a plurality of times through the boiler or underneath, through or over the boiler, and are discharged at the outlet flue located at the end of the boiler farthest from the firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

73,for tubes merely projecting into a firebox.
  
[List of Patents for class 122 subclass 75]    75Return fire tube:
 This subclass is indented under subclass 51.  Devices so arranged that the products of combustion pass through the boiler in opposite directions two or more times before they enter the outlet flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

54,72+, 81, and 85, for other structure which includes return features.
87,for horizontal fire tube boilers having U-shaped couplings for the fire tubes.
149+,for horizontal flue boilers having return fire tubes.
  
[List of Patents for class 122 subclass 76]    76Drop water firebox:
 This subclass is indented under subclass 75.  Devices having a water walled firebox depending from the boiler so arranged that the products of combustion pass directly through the lower tubes and return to the front of the boiler through the upper tubes and are discharged to the outlet flue at this point.
  
[List of Patents for class 122 subclass 77]    77Internal water tube:
 This subclass is indented under subclass 76.  Devices having water tubes within some of the flues or fire tubes, which may extend into the firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

141,and 146, for allied art.
  
[List of Patents for class 122 subclass 78]    78Flue:
 This subclass is indented under subclass 75.  Devices having a water firebox of the large flue type.

SEE OR SEARCH THIS CLASS, SUBCLASS:

50,for similar structure in horizontal or inclined tubes.
  
[List of Patents for class 122 subclass 79]    79Subjacent water arch:
 This subclass is indented under subclass 51.  Devices having a water heating arch, formed of metal walls spaced apart, located beneath the boiler, extending either only over the firebox or along the whole combustion chamber.

SEE OR SEARCH THIS CLASS, SUBCLASS:

103,and 105, for subjacent water arches formed of water-tubes.
  
[List of Patents for class 122 subclass 80]    80Subjacent flue:
 This subclass is indented under subclass 51.  Devices having one or more cylindrical sections, provided with large flues located below the main boiler and in communication therewith. The large flues generally inclose the fuel grate and serve as a firebox. At the rear of the large flues there may or may not be small fire tubes in alinement therewith.

SEE OR SEARCH THIS CLASS, SUBCLASS:

50,and 241, for analogous art.
  
[List of Patents for class 122 subclass 81]    81Subjacent transverse fire tube:
 This subclass is indented under subclass 51.  Devices having a water chamber depending from the main boiler, provided with transverse fire tubes and located in rear of the bridge wall.

SEE OR SEARCH THIS CLASS, SUBCLASS:

56,85, 86, 110, and 191, for analogous art.
  
[List of Patents for class 122 subclass 82]    82In communication:
 This subclass is indented under subclass 51.  Devices having a feed water heater located above the main boiler, in the combustion flue, heated by the products of combustion, and in open communication with the water space of the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

443,for superposed feed heaters in communication with the boiler steam space.
  
[List of Patents for class 122 subclass 83]    83Transverse diaphragm:
 This subclass is indented under subclass 51.  Devices having compartments separated by metal diaphragms transversely arranged inside the boiler, or to boilers having a combustion chamber intermediate the ends, with transverse diaphragms at each end of the combustion chamber, or to separate boilers in alinement. This subclass includes patents for progressively heating water fed to the boiler and also where the diaphragm is only for supporting the tubes to prevent vibration or where the diaphragms are for circulation purposes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

101,123, for vertical fire tube boilers with transverse diaphragms and having separate compartments.
125,151 and 425, for analogous structure.
  
[List of Patents for class 122 subclass 84]    84Great diameter over firebox:
 This subclass is indented under subclass 51.  Devices having two diameters, with that part of the boiler having the greater diameter over the firebox. The great diameter is offset from the main boiler, and the offset portion has short fire tubes passed therethrough, while long fire tubes extend through the whole length of the boiler. The products of combustion pass out of the firebox and return through the short tubes in the offset portion, and then pass in an opposite direction to the other end of the boiler, where the outlet flue is located, or they may return and pass through the upper short tubes and leave the boiler at the outlet flue located at the firebox end.

SEE OR SEARCH THIS CLASS, SUBCLASS:

56,81, 85, and 86, for similar art.
  
[List of Patents for class 122 subclass 85]    85Small diameter over firebox:
 This subclass is indented under subclass 51.  Devices having two diameters, the small diameter being over the firebox and the large diameter being beyond the bridge wall. The offset portion of the large diameter is provided with longitudinally extending fire tubes, through which the products of combustion from the firebox pass and then are passed through return fire tubes extending the whole length of the boiler. The products of combustion may then pass to the outlet flue at the front end of the boiler, or they may pass rearwardly above the boiler to the outlet flue located at the rear end, and in their final rearward passage may pass through fire tubes in an upwardly offset portion of the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

56,81, 86, 110, and 191, for analogous structure.
  
[List of Patents for class 122 subclass 86]    86Water firebox:
 This subclass is indented under subclass 85.  Devices having a water firebox.
  
[List of Patents for class 122 subclass 87]    87U-coupling:
 This subclass is indented under subclass 51.  Devices provided with U-shaped couplings connecting the fire tubes at the ends of the boiler, in order that the products of combustion may flow back and forth through the fire tubes in succession.

SEE OR SEARCH THIS CLASS, SUBCLASS:

75,for miscellaneous boilers of the horizontal fire-tube type where the products of combustion pass back and forth through the fire tubes.
360,for U-couplings.
  
[List of Patents for class 122 subclass 88]    88Upper drum:
 This subclass is indented under subclass 51.  Devices having a superposed horizontal upper-drum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

50,486 and 492, for special features.
  
[List of Patents for class 122 subclass 89]    89Rear of fire tube:
 This subclass is indented under subclass 51.  Devices provided with a water-cooled arch over the combustion chamber at the rear of the fire tubes. This arch may be formed of plates spaced apart or of water tubes or water tubes combined with solid material like firebrick.
  
[List of Patents for class 122 subclass 90]    90Water firebox:
 This subclass is indented under subclass 51.  Devices having a water firebox that are not otherwise classified.

SEE OR SEARCH THIS CLASS, SUBCLASS:

50,for horizontal or inclined fire tube boilers having a large flue for the firebox.
58+,for horizontal fire tube boilers with drop water fireboxes.
73,for horizontal fire tube boilers with the barrel of the boiler projecting into the firebox, which is of the drop water firebox type.
74,and 75+, for return fire tube boilers with water fireboxes.
107,for water walls with drop water fireboxes.
139,and 141, for water fireboxes with other types of horizontal flue boilers.
149,for boilers having a large flue, with a water firebox.
189,193+, for water fireboxes for horizontal cylindrical boilers which may or may not have horizontal fire tubes.
  
[List of Patents for class 122 subclass 91]    91Trapped circuit:
 This subclass is indented under subclass 90.  Devices with some form of water heating chamber or conduits within the firebox, connected in circuit with the main part of the boiler, with some form of sediment trap in the water circuit.

SEE OR SEARCH THIS CLASS, SUBCLASS:

59,for circulating conduits with water heaters in the firebox.
202,for horizontal cylindrical boilers having water heating tubes or chambers in circuit with the boiler, with a sediment trap in the circuit.
380,and 403, for analogous art with a trapped circuit.
  
[List of Patents for class 122 subclass 92]    92Magazine:
 This subclass is indented under subclass 90.  Devices provided with a fuel magazine.

SEE OR SEARCH THIS CLASS, SUBCLASS:

46,and 66, for miscellaneous fire tube boilers with a fuel magazine.
  
[List of Patents for class 122 subclass 93]    93Offset:
 This subclass is indented under subclass 90.  Devices, wherein the water firebox is offset at the end of the boiler so that the products of combustion pass from the firebox directly into the fire-tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

189,and 190, for offset water fireboxes so arranged that the products of combustion pass beneath the boiler upon leaving the firebox.
  
[List of Patents for class 122 subclass 94.1]    94.1Water tube type:
 This subclass is indented under subclass 93.  Devices composed of water tubes in whole or in part.
  
[List of Patents for class 122 subclass 95.1]    95.1Plural with common combustion chamber:
 This subclass is indented under subclass 90.  Devices, having multiple fireboxes and in communication with a common combustion chamber located between the fireboxes and the fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

57,60 and 96, for horizontal fire tube boilers having a plurality of water fireboxes.
64,and 100, for horizontal fire tube boilers having a water firebox, with a combustion chamber between the firebox and fire-tubes.
  
[List of Patents for class 122 subclass 95.2]    95.2Multiboilers:
 This subclass is indented under subclass 95.1.  Devices having multiple chambers for heating fluids.
  
[List of Patents for class 122 subclass 96]    96Superposed:
 This subclass is indented under subclass 90.  Devices in which the water fireboxes are superposed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

66,and 67, for special types of superposed fuel chambers.
  
[List of Patents for class 122 subclass 97]    97Downdraft:
 This subclass is indented under subclass 90.  Devices having a downdraft water grate.
  
[List of Patents for class 122 subclass 98]    98Updraft:
 This subclass is indented under subclass 90.  Devices having an updraft water grate.

SEE OR SEARCH THIS CLASS, SUBCLASS:

374,377 and 378, for structure of grate.
  
[List of Patents for class 122 subclass 99]    99Straddle:
 This subclass is indented under subclass 90.  Devices having water tubes therein straddling the fuel chamber.
  
[List of Patents for class 122 subclass 100]    100Interposed flue:
 This subclass is indented under subclass 90.  Devices of the water tube type constructed wholly or in part of water tubes, with an interposed large flue between the firebox and the fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

64,94 and 95, for combustion chambers interposed between firebox and fire tubes.
  
[List of Patents for class 122 subclass 101]    101Water smoke box:
 This subclass is indented under subclass 51.  Devices having a water cooled smoke-box.

SEE OR SEARCH THIS CLASS, SUBCLASS:

151,423, 425, and 426, for special features.
  
[List of Patents for class 122 subclass 102]    102Over bridge wall:
 This subclass is indented under subclass 51.  Devices having water tubes extending horizontally over the bridge wall.

SEE OR SEARCH THIS CLASS, SUBCLASS:

154,for horizontal flue boilers with water tubes over the bridge wall.
195+,for horizontal cylindrical boilers having fire tubes, with water tubes extending horizontally over the bridge wall, where it is immaterial whether the boiler is provided with fire tubes or not.
263,for water tube boilers having water tubes horizontal over the bridge wall.
  
[List of Patents for class 122 subclass 103]    103Rear of fire tube:
 This subclass is indented under subclass 51.  Devices having water tubes in the rear of the fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

89,and 195, for related art.
150,for closely allied art.
153,for horizontal flue boilers with water tubes.
  
[List of Patents for class 122 subclass 104]    104Over bridge wall:
 This subclass is indented under subclass 51.  Devices having rearwardly declined water tubes over the bridge wall.

SEE OR SEARCH THIS CLASS, SUBCLASS:

108,and 154, for horizontal flue boilers, with water-tubes over the bridge wall.
195+,for horizontal cylindrical boilers provided with various kinds of water-tubes in the combustion chamber.
291+,and 296, for rearwardly declined water-tubes over the bridge wall, having a longitudinally posited drum without fire-tubes over the water-tubes.
  
[List of Patents for class 122 subclass 105]    105Over bridge wall:
 This subclass is indented under subclass 51.  Devices having water tubes inclined rearwardly over the bridge wall.

SEE OR SEARCH THIS CLASS, SUBCLASS:

108,and 154, for horizontal flue boilers with water tubes over the bridge wall.
265,for rearwardly inclined water tube boilers over the bridge wall.
  
[List of Patents for class 122 subclass 106]    106Water wall:
 This subclass is indented under subclass 51.  Devices having water walls at the sides, front, or rear of the boiler, or at all of said locations. The wall may also extend across the boiler below the combustion chamber.

SEE OR SEARCH THIS CLASS, SUBCLASS:

107,and 108, for similar art.
  
[List of Patents for class 122 subclass 107]    107Drop water firebox:
 This subclass is indented under subclass 106.  Devices having a water walled firebox depending from the boiler structure.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76,and 149, for closely related art.
  
[List of Patents for class 122 subclass 108]    108Subjacent water tube:
 This subclass is indented under subclass 106.  Devices having some form of water tubes between the walls in the combustion chamber.

SEE OR SEARCH THIS CLASS, SUBCLASS:

135+,for closely allied structure.
  
[List of Patents for class 122 subclass 109]    109Inclined:
 This subclass is indented under subclass 44.  Devices placed in inclined position.

SEE OR SEARCH THIS CLASS, SUBCLASS:

47,50, 51, 54, and 110, for boilers having some of the fire tubes inclined.
  
[List of Patents for class 122 subclass 110]    110Horizontal boiler:
 This subclass is indented under subclass 44.  Subject matter relating to horizontally disposed boilers having transverse fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

56,and 191, for analogous art.
81,for horizontal fire tube boilers with transverse fire tubes.
113,for combinations of transverse fire tubes, with water tubes.
  
[List of Patents for class 122 subclass 111]    111Vertical boiler:
 This subclass is indented under subclass 44.  Subject matter relating to vertical boilers having transverse fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

187,for vertical flue boilers with transverse fire tubes.
  
[List of Patents for class 122 subclass 112]    112Water firebox:
 This subclass is indented under subclass 111.  Devices having a water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

187,for vertical flue boilers having fire tubes extending from the inner large flue to the outside of the boiler.
220,for sectional boilers.
  
[List of Patents for class 122 subclass 113]    113Water tube:
 This subclass is indented under subclass 44.  Devices having fire tubes extending transversely through the boiler and also having water tubes in communication with the boiler.
  
[List of Patents for class 122 subclass 114]    114Vertical:
 This subclass is indented under subclass 44.  Devices placed in vertical position.

SEE OR SEARCH THIS CLASS, SUBCLASS:

20,for boilers having auxiliary water heaters.
37,for vertical fire tube boilers having separate boiler compartments which may or may not be in communication with each other (one of which compartments may be used as a water heater and the other as a steam generator.)
40+,for flash boilers with vertical fire tubes.
42+,for combinations of water tube and fire tube boilers of a miscellaneous character.
48,for combinations of fire tube boilers with vertical flue boilers or fire tube boilers having a large vertical flue of a miscellaneous character.
49,for boilers having both horizontal and vertical tubes.
110,for horizontally disposed boilers with transverse vertical fire tubes.
115,and 119, for vertical cylindrical boilers with vertical fire tubes.
178+,for vertical cylindrical fire tubes above and in alinement with a vertical flue in the boiler.
  
[List of Patents for class 122 subclass 115]    115Fluid fuel:
 This subclass is indented under subclass 114.  Devices heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

22,for miscellaneous boilers heated by solid or fluid fuel.
23,for miscellaneous boilers heated by fluid fuel.
24,for boilers heated by fluid fuel which is exploded while burning.
43,for combined fire tube and water tube boilers heated by fluid fuel that are of a miscellaneous nature.
156,for vertical flue boilers heated by fluid fuel.
161,and 183, for other types of vertical flue boilers heated by fluid fuel.
167,177 and 179, for vertical flue boilers combined with internal water tubes and heated by fluid fuel.
  
[List of Patents for class 122 subclass 116]    116Central fire dome:
 This subclass is indented under subclass 114.  Devices provided with a large space or dome at the lower end of the boiler, extending into the boiler, located over the firebox, with the tubes disposed around the dome.
  
[List of Patents for class 122 subclass 117]    117Central magazine:
 This subclass is indented under subclass 114.  Devices having a centrally disposed fuel magazine.

SEE OR SEARCH THIS CLASS, SUBCLASS:

30,for miscellaneous magazine boilers.
128,for vertical fire tube boilers having a water fire box and a central fuel magazine.
157,and 168, for vertical flue boilers with a central fuel magazine.
  
[List of Patents for class 122 subclass 118]    118Internal:
 This subclass is indented under subclass 114.  Devices having sleeves, cylinders, or tubes arranged inside the boiler for aiding the boiler circulation.

SEE OR SEARCH THIS CLASS, SUBCLASS:

159,for similar devices within a vertical flue boiler.
408,for similar structure in circulation devices.
  
[List of Patents for class 122 subclass 119]    119Cylinder:
 This subclass is indented under subclass 114.  Devices in vertical cylindrical boilers.
  
[List of Patents for class 122 subclass 120]    120Offset firebox:
 This subclass is indented under subclass 114.  Devices having an offset firebox out of alinement with the fire tubes. The firebox is generally of the water firebox type.

SEE OR SEARCH THIS CLASS, SUBCLASS:

175,for vertical flue boilers with an offset water firebox.
  
[List of Patents for class 122 subclass 121]    121Return fire tube:
 This subclass is indented under subclass 114.  Devices provided with fire tubes through which the products of combustion pass upon leaving the firebox and also fire tubes through which the products of combustion return to the other end of the boiler before they enter the outlet flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

128,for this type of boiler having a central magazine.
182,for vertical flue boilers having return fire tubes.
  
[List of Patents for class 122 subclass 122]    122Water firebox:
 This subclass is indented under subclass 121.  Devices having a water firebox. The return fire tubes may be through the same boiler section or in another boiler section placed beside the other.
  
[List of Patents for class 122 subclass 123]    123Separate compartment:
 This subclass is indented under subclass 114.  Devices provided with separate compartments either by diaphragms extending across the tubes or by complete boiler sections superposed or placed side by side, and having the feed water introduced into the compartment farthest from the fire box.

SEE OR SEARCH THIS CLASS, SUBCLASS:

83,for horizontal fire tube boilers having a progressive heating of the feed water.
122,and 125, for analogous art.
  
[List of Patents for class 122 subclass 124]    124Side magazine:
 This subclass is indented under subclass 114.  Devices having a fuel magazine disposed on one or more sides of the boiler.
  
[List of Patents for class 122 subclass 125]    125Top water chamber:
 This subclass is indented under subclass 114.  Devices having a separate water chamber above the steam space, through which the fire tubes pass to prevent the leaking of flue joints or to heat feed water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

83,123 and 164, for similar art.
  
[List of Patents for class 122 subclass 126]    126Water firebox:
 This subclass is indented under subclass 114.  Devices having a water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

48,and 178+, for analogous structure.
120,for offset fireboxes.
122,for return fire tube vertical fire tube boilers with a water firebox.
  
[List of Patents for class 122 subclass 127]    127Annular:
 This subclass is indented under subclass 126.  Devices in the form of a ring or the like.

SEE OR SEARCH THIS CLASS, SUBCLASS:

29,for annular fireboxes with miscellaneous types of boilers.
184,for vertical flue boilers with an annular firebox.
  
[List of Patents for class 122 subclass 128]    128Central magazine:
 This subclass is indented under subclass 126.  Devices having a water firebox and a central fuel magazine.

SEE OR SEARCH THIS CLASS, SUBCLASS:

117,for miscellaneous vertical fire tube boilers having a central fuel magazine.
157,and 168, for vertical flue boilers with a central magazine.
  
[List of Patents for class 122 subclass 129]    129Downdraft:
 This subclass is indented under subclass 114.  Devices having a downdraft water grate.

SEE OR SEARCH THIS CLASS, SUBCLASS:

371,for miscellaneous boilers with water grates.
  
[List of Patents for class 122 subclass 130]    130Water tube:
 This subclass is indented under subclass 114.  Devices having some form of water tubes, not otherwise provided for.

SEE OR SEARCH THIS CLASS, SUBCLASS:

166+,for vertical flue boilers with water tubes in the flues.
  
[List of Patents for class 122 subclass 131]    131Internal:
 This subclass is indented under subclass 130.  Devices in which the water tubes are within the fire tubes.
  
[List of Patents for class 122 subclass 132]    132Radial loop:
 This subclass is indented under subclass 130.  Devices in which the water tubes are looped and arranged around the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

185,for vertical flue boilers with looped water tubes around a stand pipe within the flue.
244,and 281, for water tube boilers having a stand pipe with water tubes surrounding it.
  
[List of Patents for class 122 subclass 133]    133Spur:
 This subclass is indented under subclass 130.  Devices in which the water tubes are of the spur type.
  
[List of Patents for class 122 subclass 134]    134Volute:
 This subclass is indented under subclass 44.  Devices in which the tubes are in the form of a volute.

SEE OR SEARCH THIS CLASS, SUBCLASS:

261,for water tubes of similar form. (See also the search notes thereunder.)
  
[List of Patents for class 122 subclass 135.1]    135.1FLUE:
 This subclass is indented under the class definition.  Boilers having one or more large fire tubes or flues wholly or partly surrounded by the water space.

SEE OR SEARCH THIS CLASS, SUBCLASS:

6+,for industrial furnace boilers.
20,37, 47, and 48, for combinations of miscellaneous fire tube and flue boilers.
368,for miscellaneous water fire boxes.
  
[List of Patents for class 122 subclass 135.2]    135.2Alternative stack:
 This subclass is indented under subclass 135.1.  Devices having a substitute flue or fire tube.
  
[List of Patents for class 122 subclass 135.3]    135.3Sinusoidal flue:
 This subclass is indented under subclass 135.1.  Devices wherein the flue turns back on itself in an undulating manner.
  
[List of Patents for class 122 subclass 136]    136Horizontal:
 This subclass is indented under subclass 135.  Subject matter placed horizontally, not otherwise provided for.

SEE OR SEARCH THIS CLASS, SUBCLASS:

47,for miscellaneous fire tube boilers having a large horizontal flue.
78,for horizontal return fire tube boilers with a horizontal flue firebox.
80,for horizontal fire tube boilers with a large flue boiler section beneath the boiler.
409+,for similar structure used in regulating circulation.
  
[List of Patents for class 122 subclass 137]    137Plural:
 This subclass is indented under subclass 136.  A plurality of devices either posited side by side or superposed one above the other.

SEE OR SEARCH THIS CLASS, SUBCLASS:

52,for similar arrangement of fire tube boilers.
  
[List of Patents for class 122 subclass 138]    138Water tube:
 This subclass is indented under subclass 137.  Devices having water tubes in communication with the boilers.

SEE OR SEARCH THIS CLASS, SUBCLASS:

53,102, 104, and 105, for structure including horizontal flue boilers.
140+,for horizontal flue boilers with internal water tubes.
153+,for horizontal flue boilers with water tubes exterior of the boiler.
195,for horizontal cylindrical fire-tube boilers with similar arrangement.
  
[List of Patents for class 122 subclass 139]    139Drop water firebox:
 This subclass is indented under subclass 136.  Devices with a drop water firebox at one end of the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

58+,for horizontal fire tube boilers with drop water firebox of analogous structure.
141,146 and 148, for other types of horizontal flue boilers with drop water fireboxes.
  
[List of Patents for class 122 subclass 140.1]    140.1Internal water tube:
 This subclass is indented under subclass 136.  Devices having some form of water tubes in the flues.

SEE OR SEARCH THIS CLASS, SUBCLASS:

43,for horizontal flue boilers having internal water tubes heated by fluid fuel.
154,for water tubes within a large horizontal flue.
  
[List of Patents for class 122 subclass 140.2]    140.2Having water tube in flue:
 This subclass is indented under subclass 140.1.  Devices wherein the water tube is in the flue.
  
[List of Patents for class 122 subclass 141]    141Drop water firebox:
 This subclass is indented under subclass 140.  Devices having a drop water firebox with longitudinal water tubes in the flues.

SEE OR SEARCH THIS CLASS, SUBCLASS:

77,and 146, for allied art.
  
[List of Patents for class 122 subclass 142]    142Return fire tube:
 This subclass is indented under subclass 140.  Devices having return fire tubes, with some form of water tubes within the large flues.

SEE OR SEARCH THIS CLASS, SUBCLASS:

77,for analogous art.
147,for horizontal flue boilers having return fire tubes, with transverse water tubes in the flues.
149+,for horizontal flue boilers with return fire tubes.
  
[List of Patents for class 122 subclass 143]    143Spur:
 This subclass is indented under subclass 140.  Devices having spur water tubes in the flue.
  
[List of Patents for class 122 subclass 144]    144Subjacent firebox:
 This subclass is indented under subclass 140.  Devices having water tubes in the flue, with a firebox located beneath the boiler.
  
[List of Patents for class 122 subclass 145]    145Transverse:
 This subclass is indented under subclass 140.  Devices having water tubes extending across the flues and communicating with the boiler at both ends.

SEE OR SEARCH THIS CLASS, SUBCLASS:

143,for spur tubes in the flue.
  
[List of Patents for class 122 subclass 146]    146Drop water firebox:
 This subclass is indented under subclass 145.  Devices having a drop-water-firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

77,for analogous art.
141,for the same structure with longitudinally placed water tubes in the flue.
  
[List of Patents for class 122 subclass 147]    147Return fire tube:
 This subclass is indented under subclass 145.  Devices having small fire-tubes, through which the products of combustion pass, after leaving the large horizontal flues, in an opposite direction.

SEE OR SEARCH THIS CLASS, SUBCLASS:

142,146 and 149, for special features.
143,for large flues having spur water tubes therein.
  
[List of Patents for class 122 subclass 148]    148Water firebox:
 This subclass is indented under subclass 140.  Devices having a water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

77,for similar art.
141,for horizontal flue boilers with a drop water firebox, with water tubes in the flue, running longitudinally.
146,for horizontal flue boilers with transverse water tubes and with a drop water firebox.
  
[List of Patents for class 122 subclass 149]    149Return fire tube:
 This subclass is indented under subclass 136.  Devices having horizontally disposed small fire tubes, through which the products of combustion are returned through the boiler after leaving the large flues. The firebox is generally located in the large flues.

SEE OR SEARCH THIS CLASS, SUBCLASS:

47,for miscellaneous boilers having fire tubes with a horizontal flue.
74,76 and 107, for related art in the fire tube type of boiler.
141,146, 150, 151, and 410, for other types of horizontal flue boilers having return fire tubes.
  
[List of Patents for class 122 subclass 150]    150Rear water tube:
 This subclass is indented under subclass 149.  Devices with water tubes at the rear of the flues and fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

103,for similar art in a fire tube type of boiler.
  
[List of Patents for class 122 subclass 151]    151Separate:
 This subclass is indented under subclass 150.  Devices having a separate compartment at the rear of the fire tubes and flues in which feed water may be heated.

SEE OR SEARCH THIS CLASS, SUBCLASS:

425,for similar structure.
  
[List of Patents for class 122 subclass 152]    152Water grate in flue:
 This subclass is indented under subclass 136.  Devices with some form of water grate within the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

371+,for structure of water grates.
  
[List of Patents for class 122 subclass 153]    153Water tube:
 This subclass is indented under subclass 136.  Devices having water tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

102,through 105, for horizontal fire tube boilers with water tubes.
138,for plural boilers with water tubes.
  
[List of Patents for class 122 subclass 154]    154Over bridge wall:
 This subclass is indented under subclass 153.  Devices in which the water tubes extend over the bridge wall in the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

77,102, 104, 105, and 108, for related structure.
141,for closely allied art in the horizontal flue type of boiler.
  
[List of Patents for class 122 subclass 155.1]    155.1Vertical:
 Subject matter under subclasses 135.1+ placed upright.

SEE OR SEARCH THIS CLASS, SUBCLASS:

48,for miscellaneous fire tube boilers having a vertical flue.
  
[List of Patents for class 122 subclass 155.2]    155.2With flue baffle:
 This subclass is indented under subclass 155.1.  Device wherein a static structure regulates the fluid flow in a flue.
  
[List of Patents for class 122 subclass 155.3]    155.3Having exterior heating flue:
 This subclass is indented under subclass 155.1.  Devices wherein the flue is located on the outside of a fluid tank.
  
[List of Patents for class 122 subclass 155.4]    155.4Having corrugated flue:
 This subclass is indented under subclass 155.1.  Devices where the flue has parallel and alternating ridges and grooves.
  
[List of Patents for class 122 subclass 155.5]    155.5Having undulating flue:
 This subclass is indented under subclass 155.1.  Devices wherein the flue is shaped in wavelike or sinusoidal form.
  
[List of Patents for class 122 subclass 156]    156Fluid fuel:
 This subclass is indented under subclass 155.  Vertical flue boilers heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

22,for miscellaneous boilers heated by solid or fluid fuel.
23,for miscellaneous boilers heated by fluid fuel.
115,for vertical fire tube boilers heated by fluid fuel.
161,167, 177, 179, and 183, for other types of vertical flue boilers heated by fluid fuel.
  
[List of Patents for class 122 subclass 157]    157Central magazine:
 This subclass is indented under subclass 155.  Vertical flue boilers having a centrally posited fuel magazine not otherwise provided for.

SEE OR SEARCH THIS CLASS, SUBCLASS:

117,and 128, for vertical fire tube boilers with central magazines.
162,and 168, for other vertical flue boilers having a central fuel magazine.
  
[List of Patents for class 122 subclass 158]    158Water jacket:
 This subclass is indented under subclass 157.  Devices in which the magazine is water jacketed.
  
[List of Patents for class 122 subclass 159]    159Internal:
 This subclass is indented under subclass 155.  Vertical flue boilers having internal tubes, cylinders, or sleeves inside the boiler space for increasing the circulation of water.

SEE OR SEARCH THIS CLASS, SUBCLASS:

118,for similar art.
408,for circulation features of a general character.
  
[List of Patents for class 122 subclass 160]    160Concentric shell:
 This subclass is indented under subclass 155.  Vertical flue boilers comprising a plurality of concentrically posited annular water shells formed of walls spaced apart.

SEE OR SEARCH THIS CLASS, SUBCLASS:

158,for special forms of this type of boiler.
  
[List of Patents for class 122 subclass 161]    161Fluid fuel:
 This subclass is indented under subclass 160.  Devices heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

183,for spiral water conduits.
  
[List of Patents for class 122 subclass 162]    162Central magazine:
 This subclass is indented under subclass 160.  Devices having a centrally disposed fuel magazine.

SEE OR SEARCH THIS CLASS, SUBCLASS:

157+,for more generally constructed boilers with a central fuel magazine.
  
[List of Patents for class 122 subclass 163]    163Exterior drum:
 This subclass is indented under subclass 155.  Vertical flue boilers having a steam or water drum located outside of the main boiler structure.

SEE OR SEARCH THIS CLASS, SUBCLASS:

20,for similar art.
  
[List of Patents for class 122 subclass 164]    164Insulated outlet flue:
 This subclass is indented under subclass 155.  Vertical flue boilers having the outlet flue through the steam space of the boiler provided with a heat insulator to prevent heating the steam space. This insulator may be of some packing material or formed by an air chamber.

SEE OR SEARCH THIS CLASS, SUBCLASS:

125,for vertical fire tube boilers with top water chambers.
  
[List of Patents for class 122 subclass 165]    165Internal water heater:
 This subclass is indented under subclass 155.  Devices within which is some form of water heater other than water tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

160,and 185, for allied art.
166+,for vertical flue boilers having internal water tubes.
  
[List of Patents for class 122 subclass 166.1]    166.1With internal water tube:
 Vertical flue boilers under subclasses 155.1+ having water tubes within the flue in communication with the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

131,for vertical water tube boilers with water tubes in the flues.
184,through 187, for vertical flue boilers having a central standpipe provided with water tubes located in the vertical flue.
468,for boilers of that type having steam superheater.
  
[List of Patents for class 122 subclass 166.2]    166.2Loop-type tube:
 This subclass is indented under subclass 166.1.  Devices wherein the water tube is folded back and joined at the ends.
  
[List of Patents for class 122 subclass 167]    167Fluid fuel:
 This subclass is indented under subclass 166.  Devices heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

161,177, 179, and 183, for other types of vertical flue boilers heated by fluid fuel.
  
[List of Patents for class 122 subclass 168]    168Central magazine:
 This subclass is indented under subclass 166.  Devices with a fuel magazine centrally located in the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

117,and 128, for vertical fire tube boilers with a central magazine.
158,and 162, for other vertical flue boilers having a central fuel magazine.
  
[List of Patents for class 122 subclass 169]    169Coil:
 This subclass is indented under subclass 166.  Devices having coiled water tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

244+,and 247+, for structure of coiled water tubes.
  
[List of Patents for class 122 subclass 170]    170Header:
 This subclass is indented under subclass 169.  Devices in which the coils communicate with headers located within the flue.
  
[List of Patents for class 122 subclass 171]    171Contracted inlet:
 This subclass is indented under subclass 166.  Devices, with the inlet opening to the flue of smaller diameter than the flue, and having water tubes within the flue. There may or may not be a water firebox below the contracted inlet.

SEE OR SEARCH THIS CLASS, SUBCLASS:

175,and 179, for similar art.
  
[List of Patents for class 122 subclass 172]    172Header:
 This subclass is indented under subclass 166.  Devices having water tubes in communication with headers located within the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

170,for vertical flue boilers having coiled water tubes communicating with heaters located in the flue.
178,for similar structures of water tubes.
  
[List of Patents for class 122 subclass 173]    173Horizontal spur:
 This subclass is indented under subclass 166.  Devices having horizontal spur water tubes within the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

133,for vertical fire tube boilers with spur water tubes.
180,and 181, for other types of vertical flue boilers having spur water tubes.
  
[List of Patents for class 122 subclass 174]    174Internal fire tube:
 This subclass is indented under subclass 166.  Devices in which the water tubes are provided with internal fire tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

242+,for capillary tubes of this type.
271,and 348, for vertical water tubes with internal fire tubes.
  
[List of Patents for class 122 subclass 175]    175Offset water firebox:
 This subclass is indented under subclass 166.  Devices provided with an offset water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

120,for vertical fire tube boilers with offset water fireboxes.
  
[List of Patents for class 122 subclass 176]    176Transverse:
 This subclass is indented under subclass 166.  Devices in which the water tubes extend transversely across the flue and communicating at both ends with the boiler.
  
[List of Patents for class 122 subclass 177]    177Fluid fuel:
 This subclass is indented under subclass 176.  Devices heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

179,and 183, for other types of vertical flue boilers heated by fluid fuel.
  
[List of Patents for class 122 subclass 178]    178Vertical aligned fire tube:
 This subclass is indented under subclass 166.  Devices having small fire tubes in alinement with the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

48,and 126, for analogous structures in the fire tube art.
  
[List of Patents for class 122 subclass 179]    179Fluid fuel:
 This subclass is indented under subclass 178.  Devices heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

115,167 and 171, for analogous art.
  
[List of Patents for class 122 subclass 180]    180Spur water tube:
 This subclass is indented under subclass 178.  Devices having spur water tubes within the large flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

133,for vertical fire tube boilers having spur water tubes.
173,and 181, for vertical flue boilers having spur water tubes without the vertically alined fire tubes.
186,for vertical flue boilers having a spur water tube stand pipe within the flue.
  
[List of Patents for class 122 subclass 181]    181Vertical spur:
 This subclass is indented under subclass 166.  Devices having vertical spur water tubes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

133,for vertical fire tube boilers, with vertical spur water tubes.
  
[List of Patents for class 122 subclass 182.1]    182.1With return fire tube:
 Devices under subclasses 155.1+ having small vertical fire tubes, through which the products of combustion are returned through the boiler after leaving the large flues. The fire tubes may be within the same boiler section as the large flue or in a separate boiler section.

SEE OR SEARCH THIS CLASS, SUBCLASS:

121,and 122, for return fire tube vertical fire tube boilers.
  
[List of Patents for class 122 subclass 182.2]    182.2Having symmetrical arrangement of tubes:
 This subclass is indented under subclass 182.1.  Devices wherein the fire tubes are ordered in a balanced relationship.
  
[List of Patents for class 122 subclass 182.3]    182.3Having tubes offset from firebox:
 This subclass is indented under subclass 182.1.  Having tubes offset from firebox: Devices wherein the fire tubes are not directly in line with the combustion chamber.
  
[List of Patents for class 122 subclass 183]    183Fluid fuel:
 This subclass is indented under subclass 155.  Devices comprising one or more annular chambers having spiral water passages vertically posited, with or without a fluid fuel burner.

SEE OR SEARCH THIS CLASS, SUBCLASS:

161,and 501+, for related art.
  
[List of Patents for class 122 subclass 184]    184Annular firebox:
 This subclass is indented under subclass 155.  Devices having a stand pipe provided with water tubes or merely a vertical pipe extending downwardly within the flue through the fuel grate to form an annular firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

29,for miscellaneous boilers with an annular fire tube.
127,for vertical fire tube boilers with an annular water firebox.
  
[List of Patents for class 122 subclass 185]    185Loop:
 This subclass is indented under subclass 155.  Devices having a vertical stand pipe, with looped water tubes located within the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

215+,for similar art in sectional boilers.
244+,and 281, for structure of stand pipe and water tubes.
  
[List of Patents for class 122 subclass 186]    186Spur:
 This subclass is indented under subclass 155.  Devices having a stand pipe provided with spur water tubes located within the flue.

SEE OR SEARCH THIS CLASS, SUBCLASS:

184,for similar structure.
215+,for similar art in sectional boilers.
307+,for spur water tube stand pipe structure.
  
[List of Patents for class 122 subclass 187]    187Transverse fire tube:
 This subclass is indented under subclass 155.  Devices having fire tubes extending transversely through the annular water chamber formed by the inner and outer walls of the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

111,for vertical boilers with transverse fire tubes extending through the whole boiler.
  
[List of Patents for class 122 subclass 188]    188Drop water baffle:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers provided with a depending water-cooled baffle for the products of combustion, formed either of plates spaced apart, water tubes, or the combination of either of these with firebrick or some solid material.

SEE OR SEARCH THIS CLASS, SUBCLASS:

61,for drop baffles in the water firebox.
  
[List of Patents for class 122 subclass 189]    189Water roof:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers having an offset subjacent firebox provided with a water-cooled roof. The firebox in addition to the water roof may also have one or more of its walls water-cooled, thereby forming an offset subjacent water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

93+,for offset water fireboxes for a horizontal fire tube boiler.
190,for offset fireboxes, for horizontal cylinder boilers.
209,and 213, for this feature in sectional boilers.
238,336 and 352, for water tube boilers with offset fireboxes.
  
[List of Patents for class 122 subclass 190]    190Water tube:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers having an offset subjacent firebox having water tubes surrounding the fuel space.

SEE OR SEARCH THIS CLASS, SUBCLASS:

194,for analogous art.
  
[List of Patents for class 122 subclass 191]    191Beyond bridge wall:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers having subsidiary fire tube section of the boiler beyond the bridge wall. The fire tubes may be either vertical or horizontal, and if horizontal may extend either longitudinally or transversely of the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

56,81 and 85+, for closely allied structure.
  
[List of Patents for class 122 subclass 192]    192Water bridge wall:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers having a water-cooled bridge wall.
  
[List of Patents for class 122 subclass 193]    193Water firebox:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers having a firebox located beneath one end of the boiler and having one or more water walls forming the sides of the firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

58+,and 90+, for horizontal fire tube boilers with various types of water fireboxes.
139,141 and 146, for horizontal flue boilers with water fireboxes.
188,for drop water baffles.
189,for water cooled roofs.
  
[List of Patents for class 122 subclass 194]    194Water tube type:
 This subclass is indented under subclass 193.  Devices having a series of water tubes either embedded in the walls of the firebox or located just inside the walls surrounding the fuel space.

SEE OR SEARCH THIS CLASS, SUBCLASS:

190,for offset subjacent fireboxes.
  
[List of Patents for class 122 subclass 195]    195Water tube:
 This subclass is indented under the class definition.  Horizontal cylindrical boilers having some form of water tubes, water chambers, or drums in communication therewith. The cylindrical boiler may or may not be provided with fire tubes or flues.

SEE OR SEARCH THIS CLASS, SUBCLASS:

45,47, 48, 49, 50, and 51+, for various types of horizontal fire tube boilers provided with water tubes, waterwalls, drums, or chambers.
136+,for horizontal cylindrical boilers having large flues therein and provided with water tubes, water walls, drums, or water heating chambers.
  
[List of Patents for class 122 subclass 196]    196Check-valved:
 This subclass is indented under subclass 195.  Devices through which the boiler water circulates and is heated, with check valves so arranged that the feed water when introduced flows through the tubes and is heated therein and is not permitted to enter the boiler directly.

SEE OR SEARCH THIS CLASS, SUBCLASS:

69,for a similar arrangement of valves.
  
[List of Patents for class 122 subclass 197]    197Lateral-longitudinal:
 This subclass is indented under subclass 195.  Devices extending longitudinally on the sides thereof.
  
[List of Patents for class 122 subclass 198]    198Lateral-vertical:
 This subclass is indented under subclass 195.  Devices arranged vertically on the sides thereof.

SEE OR SEARCH THIS CLASS, SUBCLASS:

51,53, 138, and 153+, for analogous art.
  
[List of Patents for class 122 subclass 199]    199Firebox:
 This subclass is indented under subclass 198.  Devices in which the tubes are on each side of the firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

68,and 94, for analogous art.
  
[List of Patents for class 122 subclass 200]    200Over fuel grate:
 This subclass is indented under subclass 195.  Devices placed over the fuel grate.
  
[List of Patents for class 122 subclass 201]    201Subjacent internal fire tube:
 This subclass is indented under subclass 195.  Devices in which the water tubes are provided with internal fire tubes located in the combustion chamber beneath the boiler.

SEE OR SEARCH THIS CLASS, SUBCLASS:

267,for internal fire tubes within the water tubes.
  
[List of Patents for class 122 subclass 202]    202Trapped circuit:
 This subclass is indented under subclass 195.  Devices having a water tube heating circuit provided with some form of sediment trap in the circuit.

SEE OR SEARCH THIS CLASS, SUBCLASS:

91,398 and 404, for analogous art.
  
[List of Patents for class 122 subclass 203]    203Downdraft:
 This subclass is indented under subclass 195.  Devices having a down-draft water grate located beneath the boiler.
  
[List of Patents for class 122 subclass 204]    204Intermediate draft:
 This subclass is indented under subclass 195.  Devices provided with a plurality of fireboxes having fuel grates, at least one of which is a water-cooled grate, so arranged that the products of combustion from the fireboxes meet each other.

SEE OR SEARCH THIS CLASS, SUBCLASS:

67,and 287, for analogous art.
  
[List of Patents for class 122 subclass 205]    205Multiple series:
 This subclass is indented under subclass 195.  Devices having a plurality of fire grates, one or more of which are of the water tube type and so arranged that the products of combustion from one grate pass over or through the other grate.
  
[List of Patents for class 122 subclass 206]    206Solid and water bar:
 This subclass is indented under subclass 195.  Devices having a fuel grate consisting of solid bars and water-cooled bars combined.

SEE OR SEARCH THIS CLASS, SUBCLASS:

375,and 377, for grate structure.
  
[List of Patents for class 122 subclass 207]    207Updraft:
 This subclass is indented under subclass 195.  Devices having an updraft water grate located beneath the boiler.
  
[List of Patents for class 122 subclass 208]    208Fluid fuel:
 This subclass is indented under the class definition.  Boilers comprising flat plates provided with zigzag passages heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

356,for zigzag water tube boilers heated by fluid fuel.
  
[List of Patents for class 122 subclass 209.1]    209.1SECTIONAL:
 This subclass is indented under the class definition.  Boilers made of separate parts generally formed of cast metal sections and not otherwise classifiable.

SEE OR SEARCH THIS CLASS, SUBCLASS:

44+,135+ and 235+, for sectional water tube boilers having fire tubes, flues or water tubes.
  
[List of Patents for class 122 subclass 209.2]    209.2Feeding air:
 This subclass is indented under subclass 209.1.  Devices wherein tubes are provided to admit outside air and allow the escape of this air into the fire box once heated.
  
[List of Patents for class 122 subclass 210]    210Fluid fuel:
 This subclass is indented under subclass 209.  Sectional boilers heated by fluid fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:

23,for miscellaneous boilers heated by fluid fuel.
211,for sectional boilers heated by either solid or fluid fuel.
  
[List of Patents for class 122 subclass 211]    211Fluid or solid fuel:
 This subclass is indented under subclass 209.  Sectional boilers heated by either solid or fluid fuel or both combined.

SEE OR SEARCH THIS CLASS, SUBCLASS:

16.1,for a stand boiler (e.g., water heater, etc.) that provides hot water for domestic or household use (e.g., cooking, cleaning, washing, bathing, space heating, etc.) that may be in other than a house or home (e.g., apartment building, office building, restaurant, laundry, recreational vehicle, etc.) having a solid fuel burner.
22,for a residual solid or liquid fueled boiler.
  
[List of Patents for class 122 subclass 212.1]    212.1With magazine:
 Sectional boilers under subclasses 209.1 having a fuel storage area.

SEE OR SEARCH THIS CLASS, SUBCLASS:

30,for miscellaneous magazine boilers and see the notes thereunder for subclasses of boilers with magazines.
  
[List of Patents for class 122 subclass 212.2]    212.2With return or alternate flue:
 This subclass is indented under subclass 212.1.  Devices wherein a substitute or return flue is provided to preheat air for combustion.
  
[List of Patents for class 122 subclass 213]    213Plural firebox:
 This subclass is indented under subclass 209.  Sectional boilers having a plurality of fireboxes.

SEE OR SEARCH THIS CLASS, SUBCLASS:

232,for sectional boilers having a water grate above the main grate for supporting waste material.
  
[List of Patents for class 122 subclass 214]    214Superimposed:
 This subclass is indented under subclass 209.  Sectional boilers whose sections are superimposed and lie substantially in a horizontal plane.
  
[List of Patents for class 122 subclass 215]    215Central connection:
 This subclass is indented under subclass 214.  Devices the sections being in communication with one another at their centers.
  
[List of Patents for class 122 subclass 216]    216Fluid fuel:
 This subclass is indented under subclass 215.  Devices heated by fluid fuel.
  
[List of Patents for class 122 subclass 217]    217Water firebox:
 This subclass is indented under subclass 215.  Devices with a water firebox.
  
[List of Patents for class 122 subclass 218]    218Water firebox:
 This subclass is indented under subclass 214.  Devices with a water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

217,for horizontal sections centrally connected with a water firebox.
  
[List of Patents for class 122 subclass 219]    219Central magazine:
 This subclass is indented under subclass 218.  Devices having a central fuel magazine.

SEE OR SEARCH THIS CLASS, SUBCLASS:

212,for miscellaneous sectional boilers with fuel magazines.
  
[List of Patents for class 122 subclass 220]    220Water firebox:
 This subclass is indented under subclass 214.  Devices having water tubes provided with internal fire tubes, with a water firebox.

SEE OR SEARCH THIS CLASS, SUBCLASS:

266+,for water tube boilers having internal fire tubes.
  
[List of Patents for class 122 subclass 221]    221Annularly positioned:
 This subclass is indented under subclass 209.  Sectional boilers having vertically disposed sections around the combustion chamber.
  
[List of Patents for class 122 subclass 222]    222Central magazine:
 This subclass is indented under subclass 221.  Devices with a centrally disposed fuel magazine.
  
[List of Patents for class 122 subclass 223]    223Longitudinally positioned:
 This subclass is indented under subclass 209.  Sectional boilers having vertical sections extending longitudinally of the boiler.
  
[List of Patents for class 122 subclass 224]    224Casing:
 This subclass is indented under subclass 223.  Devices, having an inclosing casing spaced apart from the sections to allow passage for the products of combustion around the sections.