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 [Search a list of Patent Appplications for class 431]   CLASS 431,COMBUSTION
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SECTION I - CLASS DEFINITION

This is the residual class for processes of combustion or combustion starting, and for apparatus peculiarly adapted to burn or ignite materials.

SECTION II - NOTES TO THE CLASS DEFINITION

(1) Note. A fuel discharge nozzle is a subcombination of basic subject matter of this class if it is specialized for use in combustion solely (1) by discrete means transmitting flame between distinct fuel discharge areas; (2) by flashback preventing or controlling structure (3) by an incandescing component; (4) by means maintaining a reigniting flame; or (5) by flame enclosing, protecting or stabilizing structure.
(2) Note. Patents issued prior to 1940 have not in all instances been classified by their claimed disclosure so the placement of these patents does not necessarily indicate lines of classification.

SECTION III - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

See References To Other Classes, below, for information about lines with other classes.

SECTION IV - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

44, Fuel and Related Compositions,   subclasses 507+ for a match structure; subclass 643 for a residual match striking surface, per se; subclasses 530+ for fuel product of defined shape or structure; and subclasses 542+ for fuel products coated or impregnated for easier ignition.
48, Gas: Heating and Illuminating,   appropriate subclass, for an apparatus or process for the manufacture, purification, mixing, distribution or storage of heating or illuminating gas without combustion thereof. Also, when a portion of the generated gas is burned to generate the gas and another portion of the generated gas is purified, fixed or stored, classification is in Class 48.
60, Power Plants,   subclasses 39.01+ for a combustion product generator, per se, or subcombination thereof peculiarly adapted for power generation, or solely disclosed for such purpose; and appropriate subclasses for a residual device producing mechanical power or thrust from fuel.
102, Ammunition and Explosives,   subclasses 283+ for a shaped thermic or explosive charge; subclasses 335+ for a device other than a photos:graphic flash device burning a packaged charge containing both fuel and oxidizer for display, amusement flashlight or signal purposes, e.g., flare, etc.; subclasses 335+ for an explosive or thermic charge within a casing; and subclasses 464+ for a fuse, primer or igniter for igniting a thermic or explosive charge. See (1) Note of the class definition of Class 102 for a statement of the types of material used in the devices of this class.
110, Furnaces,   appropriate subclass for process of burning solid fuel even though the solid fuel be combined with a gas or liquid fuel, the line between Classes 110 and 431 relative to combustion apparatus is: Class 110 takes solid fuel burners that have a feature specialized to the burning of such fuel, e.g., a grate, solid fuel preparer or treater other than a mere preheater, a slag or ash remover, a mechanical feeder such as a conveyor, etc. Class 431 takes gaseous and liquid fuel combustion apparatus and burners utilizing a finely divided fuel dispersed in air in which the mixture merely acts as a fluid fuel stream, even though it is defined by terms such as solid fuel burner, fuel suspension burner, etc. Class 431 also takes candles, jelled fuel burners, magnesium strip burners and illuminating flash devices of the combustion type. Combustion apparatus for or a method of burning liquid waste material, however, is proper in Class 110. Also, search Class 110 for the following furnace elements, subcombinations or appurtenances: subclasses 119+ for spark arrestors; subclasses 145+ for spark and smoke conductors; subclasses 147+ for draft regulators for a furnace; subclasses 165+ for an ash receiving or handling device; subclass 172 for a furnace front; subclasses 173+ for a door specialized for use in a furnace; subclass 181 for a casing or arch specialized for use in a furnace door; subclasses 182.5+ for a conduit specialized to feeding air to a furnace; subclass 184 for a metal smoke stack specialized for use with a locomotive or portable boiler.
122, Liquid Heaters and Vaporizers,   appropriate subclasses for a heat generator, (e.g., fuel burner, etc.) specifically related to a closed holder of liquid to be heated, or combined with a specific closed liquid holder. However, when the liquid heated is fed to the burner head of a burner assembly and the closed chamber or conduit is merely an element of the burner assembly, classification is in Class 431.
123, Internal-Combustion Engines,   appropriate subclass for a device specialized to the production of power in which fuel is burned in an expansible chamber.
126, Stoves and Furnaces,   for the apparatus for the application of heat, and for the stove and furnace elements specifically provided for in the various subclasses; see particularly subclasses 144+ for a firepot or lining, subclasses 285+ for a damper, and subclasses 307+ for a stove pipe.
136, Batteries: Thermoelectric and Photoelectric,   subclasses 217+ for a residual thermoelectric generator heated by a pilot burner.
137, Fluid Handling,   appropriate subclass for a residual fluid handling or feeding invention of general utility. The recitation that a fuel is handled or that the invention comprises a burner does not bar classification in Class 137 where no particulars of a flame holding element nor significant relationship of a flame holder and fuel handler based upon the combustibility of the fuel fed to the flame holder is involved.
149, Explosive and Thermic Compositions or Charges,   appropriate subclass for an explosive or thermic composition, or charge, e.g., match composition, etc.
206, Special Receptacle or Package,   subclasses 85+ for a tobacco container with an igniter for said content and subclasses 96+ for a match packet, container or holder.
219, Electric Heating,   subclasses 260+ for an incandescent type of electrically operated igniter, per se.
221, Article Dispensing,   subclasses 136+ for an article dispenser combined with an ignition means.
236, Automatic Temperature and Humidity Regulation,   appropriate subclass for a control system regulating the temperature of a chamber or material where no more of the structure of the means supplying or removing heat is included than is necessary to bring out its relationship to the control system. It is noted that for Class 236 an igniter, flame sensor or pilot burner is a part of the control structure rather than of the controlled temperature modifying burner. It is also noted that a residual apparatus specialized to combustion and having either a broad or specific burner is classified in Class 431 where the operation of the temperature modifying burner is simply initiated or terminated by a broad "off and on" thermostat sensing and responding to the temperature of the chamber or material heated by the burner.
239, Fluid Sprinkling, Spraying, and Diffusing,   appropriate subclass for subject matter relating to the emission from a fluid handling system in modified flow, of fluid or slurry, and for the emitter member, per se. An indication that a fuel is handled or that the emitted material is burned (e.g., named welding torch, etc.) does not bar classification in Class 239 in the absence of a feature or structure dependent upon the combustion or combustibility of the fuel specializing the invention to combustion.
  • The structure listed in Notes to the Class Definition (1) Note above and the following features or elements are among those that distinguish a specialized fuel discharger classifiable in Class 431 from a Class 239 structure: (1) A device for starting combustion at the discharger such as a pilot or igniter even nominally recited. (2) A sensor of combustion heat in, or burner flame at the discharger, controlling feed to the discharger.
313, Electric Lamp and Discharge Devices,   appropriate subclass for an air gap discharge device (e.g., spark plug etc.), per se.
361, Electricity: Electrical Systems and Devices,   subclasses 247+ for a residual electrical igniting system.
362, Illumination,   appropriate subclasses for an illumination device comprising a light source, e.g., a burner etc., combined (1) with a device that encloses the light source and transmits the light therefrom or (2) with a light distributor. However, patents issued prior to 1940, having a conventionally shown light transmitting or distributing device and specific burner structure have been placed in the appropriate burner subclass in Class 431.
417, Pumps,   subclasses 73+ , for a pumping system operated by combustion displacement of the liquid and appropriate subclass for a pumping system that may handle fuel where combustion of the material handled is not involved.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   appropriate subclasses for apparatus for generating a treating agent by burning a combustible material, a combustion or reaction device for purifying a gas, or with means for recovering, mixing, separating, or otherwise handling as a product material formed in the device or residual chemical apparatus.
423, Chemistry of Inorganic Compounds,   appropriate subclass, for inorganic compounds and nonmetallic elements including their manufacture by chemical reaction, and note especially subclasses 212+ for exhaust gas purification or separation.
429, Chemistry: Electrical Current Producing Apparatus, Product, and Process,   subclasses 12+ for a battery generating current by feeding a gas into a cell to react with fluids in the cell, (e.g., fuel cell, etc.).
432, Heating,   appropriate subclass, for a residual method or apparatus for generating heat and applying it to materials.

SECTION V - GLOSSARY

BURNER

Term generic to "burner assembly", "burner head" and "flame holder".

BURNER ASSEMBLY

A unitary device or fixture including a flame holder and associated feeding or supporting elements.

BURNER HEAD

A device by which fluent fuel is passed to a combustion space where it forms a flame projecting from the device.

CLEANING

The dislodging of extraneous matter or incrustations.

COMBUSTION

The direct combination of oxygen gas and a burnable substance.

FLAME HOLDER

Generic term for the part of a combustion device confining the flame or supporting the base of a flame. It includes burner heads, the flame supporting portion of wicks, the pots of pot type burners, etc.

FLASH BACK

The spread of flame from a combustion area into a feed passage of a burner head.

FLINT

A body of material that produces igniting sparks when struck. It is generally made of an alloy of iron and cerium.

PILOT BURNER

A small auxiliary unit used to ignite a principal flame holder.

PURGING

The removal of unwanted material.

RETARDER

A device that provides for the delay of completion of performance of an operation after its initiating signal has been given, e.g., dashpot, time delay switch, etc.

SCAVENGING

The flushing out of unwanted gas or gas mixture by another gas or gas mixture.

SHUTDOWN

The term is used in this class to indicate that a combustion device has been stopped and that it cannot be made to operate except by manual intervention.

SUBCLASSES

[List of Patents for class 431 subclass 1]    1COMBUSTION BURSTS OR FLARE-UPS IN PULSES OR SERIAL PATTERN
 This subclass is indented under the class definition.  Subject matter including means or steps for causing combustion of a continuing series of intermittent fuel charges which create a peak combustion followed by a minimum combustion rate, regularly or in definite repeating patterns.

SEE OR SEARCH CLASS:

60, Power Plants,   subclasses 39.76+ for an intermittent combustion type of combustion product generator disclosed solely for use for powder production.
137, Fluid Handling,   subclasses 624.13+ for a timer or programmer controlled fluid handling system of general utility providing for a repeating cycle.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclasses 99+ for a fluid sprinkling or spraying device of general utility with means causing intermittent interruption of supply to the distributing means and subclass 101 for a sprinkling device of general utility with means for fluctuating flow or pressure of fluid supplied to it.
251, Valves and Valve Actuation,   subclasses 48+ for a fluid retarder or timer for a valve that may produce a pulsed feeding.
441, Buoys, Rafts, and Aquatic Devices,   subclass 13 for a flashing aquatic buoy.
  
[List of Patents for class 431 subclass 2]    2PROCESS OF COMBUSTION OR BURNER OPERATION
 This subclass is indented under the class definition.  Processes pertaining to: burning fuel, operating a burner, or starting combustion.

SEE OR SEARCH CLASS:

110, Furnaces,   subclasses 341+ for methods of operating refuse incinerators and solid fuel furnaces.
137, Fluid Handling,   subclasses 3+ for a process not specialized to combustion for the mixing of plural fluids of diverse characteristics or conditions.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclasses 1+ for a process of sprinkling, spraying or diffusing a fluid (e.g., fuel) not specialized to combustion.
  
[List of Patents for class 431 subclass 3]    3Decarbonizing, cleaning or purging
 This subclass is indented under subclass 2.  Processes involving (1) the addition of a cleansing or decarbonizing substance to the fuel; (2) a procedure that eliminates or prevents the formation of carbon and other deposits in the burner; or (3) clearing residual or undesired matter (e.g., vapor) out of a burner assembly.

SEE OR SEARCH THIS CLASS, SUBCLASS:

29+,for the automatic control of scavenger means.
32,for the automatic control of cleaning means.
121+,for combustion apparatus with cleaning, purging or scavenging means.

SEE OR SEARCH CLASS:

44, Fuel and Related Compositions,   subclasses 300+ for a liquid fuel admixed with anti-oxidants, corrosion inhibitors, gum inhibitors, stabilizers, preservatives in general etc.
137, Fluid Handling,   subclasses 15.01 through 15.26for a process of cleaning, repairing, or assembling.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclass 9 for a fluid sprinkling, spraying or diffusing process not requiring combustion involving dissolving or mixing a material in a flowing liquid stream and combining the stream with air, gas or steam.
  
[List of Patents for class 431 subclass 4]    4Feeding flame modifying additive
 This subclass is indented under subclass 2.  Processes including feeding a substance to the flame additional to the normal fuel and oxidizing material to act as a protective agent or to give the flame some special characteristic.

SEE OR SEARCH CLASS:

44, Fuel and Related Compositions,   subclasses 300+ for a liquid fuel composition that may include a flame modifying additive.
48, Gas: Heating and Illuminating,   sub- classes 89+ for a retort generating heating or illuminating gas fed with steam or water, and subclasses 204+ for a heating or illuminating gas process involving water or steam.
60, Power Plants,   subclass 775 for a combustion products generating process involving the addition of steam or water to the combustion products.
126, Stoves and Furnaces,   subclass 59.5 for an orchard device generating smoke by combustion.
  
[List of Patents for class 431 subclass 5]    5Burning waste gas, e.g., furnace gas, etc.
 This subclass is indented under subclass 2.  Processes of burning combustible constituents remaining in the gaseous waste effluent of an industrial or power plant or process.

SEE OR SEARCH THIS CLASS, SUBCLASS:

202,for the structural installation of a combustion device that may use waste gas as fuel, e.g., flare burner, etc.

SEE OR SEARCH CLASS:

60, Power Plants,   subclasses 272+ , for the handling or treatment of the exhaust of an internal combustion engine.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 198+ for a furnace that may be used for such purification.
423, Chemistry of Inorganic Compounds,   subclasses 210+ for purifying or separating gases by chemical reaction and note especially 212+ for exhaust gases.
  
[List of Patents for class 431 subclass 6]    6Starting or shutdown procedure
 This subclass is indented under subclass 2.  Processes involving: (1) initial supplying of burner feed; (2) ignition of fuel; or (3) steps bringing about termination of combustion.

SEE OR SEARCH CLASS:

60, Power Plants,   subclasses 776 through 777for a process of ignition of a combustion products generator disclosed solely for use in power production.
  
[List of Patents for class 431 subclass 7]    7In a porous body or bed, e.g., surface combustion, etc.
 This subclass is indented under subclass 2.  Processes of injecting fuel into a bed of refractory material or a porous refractory member and burning it therein or adjacent its surface.

SEE OR SEARCH THIS CLASS, SUBCLASS:

170,for a furnace in which combustion takes place in a permeable mass.
326+,for a porous capillary, particulate or sieve-like flame holder.
  
[List of Patents for class 431 subclass 8]    8Flame shaping, or distributing components in combustion zone
 This subclass is indented under subclass 2.  Processes involving the manner in which the feed is discharged into the region where combustion takes place, or the manner in which the flame is shaped into a pattern.
  
[List of Patents for class 431 subclass 9]    9Whirling, recycling material, or reversing flow in an enclosed flame zone
 This subclass is indented under subclass 8.  Processes in which the shaping of the flame or distributing the components includes (1) whirling the combustion components within the combustion zone; or (2) directing removed or burning material towards or into the incoming feed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

115+,for combustion product return structure.
173,for feed projected tangentially to the wall of a circular combustion chamber.
  
[List of Patents for class 431 subclass 10]    10Oxidizer added to region of incomplete combustion
 This subclass is indented under subclass 8.  Processes including the step of supplying a distinct stream of an oxidizer, such as air, into a burning mixture of fuel and oxidizer.

SEE OR SEARCH THIS CLASS, SUBCLASS:

351,for a flame holder including means feeding air at axially spaced points of the flame.
  
[List of Patents for class 431 subclass 11]    11Heating feed
 This subclass is indented under subclass 2.  Processes of heating either the fuel or oxidizer prior to its discharge into a combustion zone.

SEE OR SEARCH THIS CLASS, SUBCLASS:

36+,for the automatic control of the burner feed heating structure.
161+,for a furnace heated furnace feed line.
207+,for a heated feed line section feeding a flame holder.

SEE OR SEARCH CLASS:

48, Gas: Heating and Illuminating,   subclasses 197+ for a process for the mere generation of heating or illuminating gas.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclass 13 for a process of sprinkling, spraying or diffusing not specialized to combustion including heating or cooling of the sprayed material.
  
[List of Patents for class 431 subclass 12]    12Controlling or proportioning feed
 This subclass is indented under subclass 2.  Processes controlling the supply of fuel or air discharged into the combustion zone.

SEE OR SEARCH CLASS:

137, Fluid Handling,   subclass 6 for a process comprising controlling the mixing of plural fluids of diverse characteristics or conditions by the heat of combustion of the mixture.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclasses 8+ for a sprinkling, spraying or diffusing process not specialized to combustion including the steps of mixing or combining air, gas or steam with the material to be sprayed.
  
[List of Patents for class 431 subclass 13]    13WITH INDICATOR OR INSPECTION MEANS
 This subclass is indented under the class definition.  Apparatus including (1) an indicating, registering, recording or alarm means for conveying information about a condition of a combustion or combustion starting apparatus, or (2) means which permits inspection of normally hidden parts of combustion apparatus or combustion starting apparatus.

SEE OR SEARCH CLASS:

116, Signals and Indicators,   subclass 7 for a burglar alarm that also ignites a lamp or match; and subclasses 101+ for an alarm actuated by change in temperature, e.g., fire alarm, incubator, etc.
137, Fluid Handling,   subclasses 551+ for a fluid handling system of general utility including an indicator, register, recorder, alarm or inspection means.
236, Automatic Temperature and Humidity Regulation,   subclass 94 for automatic temperature and humidity regulation apparatus thermostatically operated and including an indicator or alarm.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclasses 71+ for fluid sprinkling, spraying and diffusing apparatus of general utility with a signal, indicator, recorder, meter or changeable exhibitor.
340, Communications: Electrical,   subclasses 577+ for an electrical communications system not specialized for use with a specific flame holder responsive to flame.
356, Optics: Measuring and Testing,   subclass 315 , for spectroscopic analysis apparatus and subclass 417 for flame photometers comprising a flame holder, a means for feeding a sample to the flame and flame observation means.
374, Thermal Measuring and Testing,   subclasses 100+ for a device for measuring or testing temperature.
  
[List of Patents for class 431 subclass 14]    14Correlated with action of condition responsive burner control
 This subclass is indented under subclass 13.  Apparatus associated with a burner having a condition responsive control and in which the indicating or inspecting means is actuated by the control to convey to the operator information concerning a condition of the burner.
  
[List of Patents for class 431 subclass 15]    15Shutdown or aborted start attempt indicated
 This subclass is indented under subclass 14.  Apparatus in which the control has (1) reached a position necessitating external intervention to start, i.e., shutdown, and the indicator informs the operator that such a position has been reached; or (2) sensed that a new start attempt is necessary and informs the operator that such an attempt is being or has been made.
  
[List of Patents for class 431 subclass 16]    16Responsive to gas leakage, overflow, abnormal pressure or electrical component malfunction
 This subclass is indented under subclass 15.  Apparatus that: (1) responds to sensed leakage, overflow or pressure outside of a predetermined range or (2) responds to an indication by an electrical test circuit of electrical component deficiency or failure.
  
[List of Patents for class 431 subclass 17]    17Burner component position indicator
 This subclass is indented under subclass 13.  Apparatus wherein the indicator gives information concerning the position or relative movement of some part of a burner apparatus or burner control.
  
[List of Patents for class 431 subclass 18]    18TIMER, PROGRAMMER, RETARDER OR CONDITION RESPONSIVE CONTROL
 This subclass is indented under the class definition.  Apparatus whereby (1) a control is exerted by means sensing an environmental or operating condition; (2) the time at which an actuation is performed is controlled; (3) the length of time taken to perform an operation is controlled; (4) there is means providing a sequence of events set to occur at predetermined intervals; or (5) there is a means terminating a single operation in a fixed position to restart an additional cycle, which cycle is more complex than a mere starting or stopping of a single device.

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236, Automatic Temperature and Humidity Regulation,   appropriate subclass for a residual system including a temperature modifier (e.g., burner, etc.) and a means sensing the temperature of a chamber or material acted upon by the modifier; the sensing means regulating the temperature of the chamber or material by controlling the operation of the modifier.
700, Data Processing: Generic Control Systems or Specific Applications,   subclasses 1 through 89for data processing control systems wherein the control system is claimed generically, and subclasses 266-274 for chemical process control or monitoring systems, particularly subclass 274 for control of combustion or heating apparatus.
  
[List of Patents for class 431 subclass 19]    19Responsive to combustion chamber pressure
 This subclass is indented under subclass 18.  Apparatus , in which a control of a burner element is effected in response to a sensed pressure within a chamber in which fuel is burned.
  
[List of Patents for class 431 subclass 20]    20Of or by exhaust damper or exhaust pump
 This subclass is indented under subclass 18.  Apparatus in which (1) a pump or flow controller in a line by which combustion products are removed from a combustion chamber is controlled or (2) a means responsive to the position or condition of operation of such a pump or flow controller exerts a control.

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110, Furnaces,   subclasses 147+ for a draft regulator for a solid fuel furnace.
126, Stoves and Furnaces,   subclasses 285+ for a cooking stove damper and its operator.
236, Automatic Temperature and Humidity Regulation,   subclass 45 for the regulation of temperature by means controlling the draft of a heater.
  
[List of Patents for class 431 subclass 21]    21By combustion destructible element, e.g., fusible plug, etc.
 This subclass is indented under subclass 18.  Apparatus in which a control actuation results from the destruction of a heat fusible or consumable connection responsive to heat of combustion.

SEE OR SEARCH CLASS:

122, Liquid Heaters and Vaporizers,   subclass 504.1 and 504.3 for a fusible type safety device in a boiler.
126, Stoves and Furnaces,   subclass 287.5 for a stove having a fusible release damper.
137, Fluid Handling,   subclasses 72+ for a heat destructible or fusible control element in a fluid handling system of general utility.
  
[List of Patents for class 431 subclass 22]    22By sensing of gas leakage, flashback or escaped flame
 This subclass is indented under subclass 18.  Apparatus wherein the sensing means is responsive to (1) the presence of gaseous combustion material outside of its normal flow path or outside of its confiner during shutdown; or (2) the presence of combustion outside of the normal combustion zone.

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16,for a control system including an indicator responsive to leakage, overflow, or abnormal pressure.
  
[List of Patents for class 431 subclass 23]    23Of means protecting burner component from combustion heat
 This subclass is indented under subclass 18.  Apparatus in which the likelihood of damage to an element of a burner assembly, e.g., igniter, nozzle, etc. is prevented or lessened by a controlled actuation of a device that (1) moves the element relative to the flame area (2) moves a baffle shielding the element from the frame area (3) directs the flow of a cooling fluid over the element or (4) otherwise modified the transfer of heat to the element from the flame area.
  
[List of Patents for class 431 subclass 24]    24With test circuit checking or analyzing flame sensing circuit for malfunction
 This subclass is indented under subclass 18.  Apparatus including structure response to a signal indicating abnormality or malfunction that is produced by an electrical circuit means which (1) tests or checks a combustion sensor and its circuit or (2) analysis a signal from a combustion sensor to distinguish a tone flame signal from a false signal.

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340, Communications: Electrical,   subclasses 514+ for an electrical communication system of general application automatically responsive to a condition having means for testing the sensor or the means conveying the signal from the sensor to a control or indicator.
  
[List of Patents for class 431 subclass 25]    25Utilizing unidirectional electrical conducting effect of flame
 This subclass is indented under subclass 24.  Apparatus in which the circuit has one response to the flow of current through a gap device in the flame area when the current has been changed from alternating to direct by the rectifying effect of the flame and another response to an unrectified current which is an indication of a short circuit at the gap or some other abnormality in the sensor circuit.

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340, Communications: Electrical,   subclass 579 for an electrical communication system of general utility in which a flame sensor responds to the ionization or rectification properties of a flame.
  
[List of Patents for class 431 subclass 26]    26Test circuit activated, then inactivated in starting
 This subclass is indented under subclass 24.  Apparatus in which a starting means connects a checking circuit into a flame sensing circuit as a preliminary to fuel feed and subsequently disconnects the checking circuit.

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340, Communications: Electrical,   subclass 515 for the testing of an automatically responsive communications system of general utility having a test structure for the system including means simulating the condition being sensed.
  
[List of Patents for class 431 subclass 27]    27Providing repeated start attempts prior to shutdown upon failure to establish combustion
 This subclass is indented under subclass 18.  Apparatus in which a failure to sense flame in the proving period of a start program reinitiates the start program; said apparatus including structure causing shutdown requiring reset after one or more reinitiations of the start program.

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70,for a control that provides for recycle through a proving period on the sensing of a failure of an established flame.
  
[List of Patents for class 431 subclass 28]    28Actuation sequence of electric feed heater and feed flow controller or igniter
 This subclass is indented under subclass 18.  Apparatus which, on starting, provides for activation of an electrical heater for the burner or burner feed and subsequently for admission of fuel to the burner or for triggering of an igniter.
  
[List of Patents for class 431 subclass 29]    29Control of purger, of scavenger or of combustion start-up delay period
 This subclass is indented under subclass 18.  Apparatus wherein a timing, retarding or programming means (1) effects the operation of a device which (a) supplies a quantity of fluid other than a combustible mixture to cleanse the burner of any undesirable fluid or (b) drains or otherwise removes undesirable fluid from the burner between combustion stopping and starting; or (2) causes upon the actuation of means calling for a combustion operation a predetermined period of inaction of any fire producing elements.

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3,for processes involving decarbonizing, cleaning or purging.
  
[List of Patents for class 431 subclass 30]    30Of scavenging or purging pump
 This subclass is indented under subclass 29.  Apparatus wherein the control provides for the operation of a mechanical impelling means to flush the burner with noncombustible material (e.g., air, steam, etc.) during the scavenging or combustion start up delay period.
  
[List of Patents for class 431 subclass 31]    31Scavenging or purging period started by combustion demand
 This subclass is indented under subclass 30.  Apparatus in which, during initiation of a combustion period, the device for moving the cleansing fluid is activated for a predetermined time prior to actuation to combustion starting position of means controlling the necessary fire producing elements, (e.g., fuel supplier, igniter, etc.).
  
[List of Patents for class 431 subclass 32]    32Of cleaning means
 This subclass is indented under subclass 18.  Apparatus in which the control or actuation is of structure dislodging extraneous matter or incrustations from burner elements.
  
[List of Patents for class 431 subclass 33]    33Of extinguishing means
 This subclass is indented under subclass 18.  Apparatus including structure actuating a means to put out a burner flame other than by shutting off the fuel.

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122, Liquid Heaters and Vaporizers,   subclasses 504+ for a safety device for a steam boiler comprising an automatic extinguisher.
  
[List of Patents for class 431 subclass 34]    34Wick cover actuated in response to tilting of burner
 This subclass is indented under subclass 33.  Apparatus wherein the flame is put out by a smothering cap actuated in response to tilting of the burner.
  
[List of Patents for class 431 subclass 35]    35By candle length or fuel quantity
 This subclass is indented under subclass 33.  Apparatus including means for extinguishing the flame automatically when a predetermined portion of a candle has been consumed or when a predetermined quantity of fuel has been consumed.
  
[List of Patents for class 431 subclass 36]    36Of or by burner feed supply heating structure
 This subclass is indented under subclass 18.  Apparatus in which the control is of or by, a condition of heat generation or transfer structure by which fluid for supply to a combustion zone of an associated burner is heated.

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11,for a process for preheating feed.
31,for a burner having an electrical heater controlled to preheat a burner or burner feeder before attempting ignition of the burner.
  
[List of Patents for class 431 subclass 37]    37By controlling admittance of feed to structure
 This subclass is indented under subclass 36.  Apparatus in which the flow of feed fluid into the feed heating structure is controlled.
  
[List of Patents for class 431 subclass 38]    38By pressure of feed in structure
 This subclass is indented under subclass 37.  Apparatus in which the feed admission mean is controlled by means sensing the pressure within the feed containing section of the structure.

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48, Gas: Heating, and Illuminating,   subclass 106 for a retort not associated with a fuel burner regulated by the pressure of the gas either in the retort or gasometer.
  
[List of Patents for class 431 subclass 39]    39By level of liquid feed in structure
 This subclass is indented under subclass 37.  Apparatus in which the feed admission means is controlled by means measuring the liquid level in the fuel containing section of the structure.
  
[List of Patents for class 431 subclass 40]    40By linear expansion of feed holder
 This subclass is indented under subclass 37.  Apparatus including structure by which variation in length of a fluid containing section of the feed heating structure is utilized in the actuation of a feed admission controller.
  
[List of Patents for class 431 subclass 41]    41Supply of heat to heating structure controlled
 This subclass is indented under subclass 36.  Apparatus in which a means sensing a condition of the heating structure actuates a controller of the heat supply of the structure.
  
[List of Patents for class 431 subclass 42]    42Sensor of first burner controls second burner, e.g., pilot and main, etc.
 This subclass is indented under subclass 18.  Apparatus in which a means responsive to a condition of one burner head or assembly effects or locks a control means of a second burner head or assembly.

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137, Fluid Handling,   subclasses 65+ for a control subcombination of a burner assembly comprising a combustion failure responsive fuel safety cut off for a burner feed line where the subcombination does not include the flame holder fed by the controlled line.
  
[List of Patents for class 431 subclass 43]    43With electrical igniter
 This subclass is indented under subclass 42.  Apparatus having an electrical spark producing means or an electrical heating element associated with one of the burners to ignite fuel supplied to the burner.
  
[List of Patents for class 431 subclass 44]    44Igniter deenergized by fuel pressure variation in start effort
 This subclass is indented under subclass