CPC Definition - Subclass F23D
This place covers:
Burners, i.e. devices by which fluid fuel, or solid fuel suspended in air, is passed to a combustion space where it burns to produce a self-supporting flame, for example, burners in which:
- pulverulent solid fuel is entrained into the combustion space by air;
- liquid fuel is transported by capillary action to the combustion space where it evaporates, e.g. wick burners;
- liquid fuel evaporates from an open fuel surface, e.g. pot burners;
- liquid fuel is sprayed into the combustion space by fluid pressure;
- liquid fuel is entrained into the combustion space by a stream of gaseous medium, for example, air or steam;
- liquid fuel is vaporised within a conduit and released in gaseous form into the combustion space;
- liquid fuel is dispersed into the combustion space by mechanical means, e.g. ultrasonic vibrations or centrifugal action;
- gaseous fuel mixed with air is released into the combustion space;
- gaseous fuel is released into the combustion space where it is mixed with air; or
- pulverulent, liquid or gaseous fuels are used simultaneously or alternately.
This subclass is the main function-oriented place for burners. Classification is always made in this subclass if the subject matter is of general interest for burners.
Burners are used in many fields where heat is generated or used. Burners per se are only classified in these application fields if they are specially adapted for a specific application, for example coating by flame spraying. Examples of application fields can be found in the section "References relevant to classification in this subclass" below. In case of doubt, classification should be made both in this subclass and the application field.
Classification is made in F23C if the subject matter to be classified, in addition to a burner, includes further features of a combustion apparatus, such as a particular form of combustion chamber or a particular arrangement of burners in a combustion chamber.
Feeding air
Air supply means that are arranged in immediate connection with the fuel-feeding conduit of a burner, for example concentric with it, are considered to be part of the burner. Means for feeding air otherwise than in immediate connection with the fuel-feeding conduit of a burner, for example arrangements for feeding secondary air at points distant from a burner, are classified in F23C 7/00 or F23L.
Control of combustion, methods of combustion
With the exception of devices or methods that are specially adapted to particular types of burners, for example the matter of the following groups:
- Wick-adjusting devices, F23D 3/28
- Maintaining a predetermined amount of fuel in evaporators, F23D 5/14
- Provision for varying the rate at which liquid fuel is sprayed, F23D 11/26
- Devices on vaporisers for controlling the feeding of fuel, F23D 11/46
- Devices for simultaneous control of gas and combustion air, F23D 14/60
this subclass does not cover control of combustion, which is covered by F23N, or methods of combustion, which are covered by F23C.
Catalytic combustion
With the exception of radiant gas burners using catalysis for flameless combustion, which is covered by F23D 14/18, this subclass does not cover the combustion of fluid fuels in the presence of catalytic material, which is covered by F23C 10/01, F23C 13/00 and F23G 7/07.
Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:
Flame throwers for destroying noxious animals or plants | |
Bakers' ovens | |
Cooking devices, e.g. travelling cookers or barbecues | |
Soldering | |
Gas flame welding or cutting | |
Cutting, scarfing or desurfacing by applying flames | |
Surface shaping of plastics by flame treatment | |
Joining of plastics using flames coming in contact with at least one of the parts to be joined | |
Using burners in chemical vapour deposition | |
Heating boreholes or wells with burners | |
Using burners for regenerating exhaust gas filters | |
Gas-turbine plants | |
Jet-propulsion plants | |
Using burners for ignition of internal combustion engines | |
Incandescent mantles | |
Non-electric portable lighting devices | |
Non-electric non-portable lighting devices | |
Arrangements of mantles or other incandescent bodies on lighting burners | |
Details of lighting devices employing combustion as light source | |
Steam boilers | |
Arrangement of burners in combustion apparatus | |
Methods or apparatus specially adapted for combustion of waste or low-grade fuels, e.g. waste oil, waste liquors or waste gases | |
Lighters containing fuel | |
Ignition using burners | |
Generating combustion products of high pressure or high velocity, e.g. gas turbine burners | |
Stoves or ranges for liquid or gaseous fuels | |
Fluid heaters having heat-generating means, e.g. heating boilers | |
Arrangement of burners in fluid heaters | |
Arrangement of burners in furnaces or ovens for heat treatment | |
Using burners for cleaning heat exchangers | |
Flame-throwers for attack or defence |
Attention is drawn to the following places, which may be of interest for search:
Mixing a gas with another gas or vapour and flow mixers in general | |
Spraying or atomising apparatus in general; Nozzles in general | |
Fuels | |
Candles | |
Pressure vessels for gases | |
Methods or apparatus for combustion using fluid fuel or solid fuel suspended in air | |
Air supply specially adapted for combustion of fluid fuels | |
Combustion in a fluidised bed of fuel or other particles | |
Apparatus in which combustion takes place in pulses influenced by acoustic resonance in a gas mass | |
Arrangement of devices for supplying chemicals to fire | |
Feeding liquid or gaseous fuel to combustion apparatus | |
Supply of air or non-combustible liquids or gases to combustion apparatus in general | |
Details of combustion chambers, e.g. linings, doors or baffles | |
Regulating or controlling combustion in general |
In this subclass, methods are classified in the groups which cover the apparatus used.
Multiple classification is mandatory when:
- the subject matter to be classified deals with air supply means which are part of a burner, but no relevant subgroup is available in F23D, e.g. arrangements of swirling vanes in a premix gas burner have to be classified in F23C 7/004 and F23D 14/02;
- the subject matter to be classified, in addition to a burner, includes further features of the air supply means that are of interest, for example, a particular form of a swirling vane, even if a relevant subgroup is available in F23D, e.g. an arrangement of adjustable swirling vanes in a non-premix gas burner having separate air and gas feed conduits have to be classified in F23C 7/006 and F23D 14/24.
Indexing codes F23D 2200/00-F23D 2900/00 are available for further classification.
In this place, the following terms or expressions are used with the meaning indicated:
air | a mixture of gases containing free oxygen and able to promote or support combustion |
burner | a device by which fluid fuel or solid fuel suspended in air is passed to a combustion space where it burns to produce a self-supporting flame. A burner includes means for feeding air that are arranged in immediate connection with a fuel feeding conduit, for example, concentric with it. |
combustion | a heat-producing sequence of chemical reactions between a burnable substance and molecular oxygen, e.g. in air, in most cases generating light in the form of flames or a glow |
combustion chamber | a chamber in which fuel is burned to establish a self-supporting fire or flame and which surrounds that fire or flame |
combustion space | the zone downstream of the fuel (and, where applicable, air) outlet where the reaction takes place between air and fuel |
fuel | any combustible material that can be burned, regardless of whether the main purpose of burning it is for releasing energy therefrom or for disposing of it or rendering it less harmful |
pilot flame | a small flame that is lit or kept alight in order to provide ignition to a more powerful burner |
primary air | air supplied to the burning fuel in order to liberate combustible gases |
retention flame | a small flame that is kept alight in order to maintain the uninterrupted operation of a more powerful burner |
secondary air | air supplied to the combustible gases liberated by the primary air in order to complete their combustion. The expression "secondary air" covers "tertiary air", etc. |
torch | a burner fired with fuel gas and oxygen and specially adapted to apply heat to a workpiece, for example, for use in welding, cutting or brazing |
Attention is drawn to the following places, which may be of interest for search:
Disposition of burners |
When classifying in this group add codes F23D 2201/00-F23D 2201/30 if appropriate.
This place covers:
Burners specially adapted for combusting a fine mixture of solid fuel paricles and a liquid, e.g. a slurry of pulverized coal in water.
Attention is drawn to the following places, which may be of interest for search:
Mixing solid fuel with a liquid, e.g. preparing slurries |
Attention is drawn to the following places, which may be of interest for search:
Combinations of different spraying or vaporising means |
This place covers:
Illustrative examples of the subject matter classified in this place:
1. Liquid fuel is sprayed into the combustion space by fluid pressure
2. Liquid fuel is entrained into the combustion space by a stream of gaseous medium, for example, air or steam
3. Liquid fuel is vaporised within a conduit and released in gaseous form into the combustion space
Attention is drawn to the following places, which may be of interest for search:
Nozzles for burners using a direct spraying action of liquid droplets or vaporised liquid; Cleaning devices therefor | |
Combustion apparatus characterised by arrangements for air supply | |
Blast-producing apparatus before the fire |
Attention is drawn to the following places, which may be of interest for search:
Nozzles for burners using a direct spraying action of liquid droplets or vaporised liquid; Cleaning devices therefor | |
Combustion chambers with casings, linings or walls with the shape of bricks or blocks used specially adapted for burner openings |
This place covers:
Spraying of liquid fuel droplets being induced by vaporised fuel.
Ultrasonic devices technically operate at frequencies greater than 20 kHz, but devices operating at lower frequencies may be placed in F23D 11/34 if they have a similar function.
Attention is drawn to the following places, which may be of interest for search:
Spraying nozzle combined with forced draft fan in one unit | |
Spraying nozzle arranged within furnace openings | |
Nozzles in general |
This place covers:
Liquid fuel burners characterised by the means for starting the combustion, e.g. fixing, locating or assembling the ignition device to the burner
This place does not cover:
Igniting |
Attention is drawn to the following places, which may be of interest for search:
Starting or igniting devices associated to gas fuel burners |
Attention is drawn to the following places, which may be of interest for search:
Vaporising devices per se |
This place covers:
This subgroup covers:
Atmospheric burners referring to burners that are purely induction type burners where air is drawn into the burner without any help of blowers or fans for the injection of fuel draws air into the burner. A Bunsen burner is an example of such a burner.
Aerated burners referring to burners where a fan or blower is used, in addition to the induction effect of fuel injection, to supply air to the burner. The fan can be forced draft or induced draft type.
This place does not cover:
Torches, e.g. for brazing or heating |
Attention is drawn to the following places, which may be of interest for search:
Inverted burner, e.g. for illumination | |
Burners using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air | |
Burners specially adapted for use with means for pressurising the gaseous fuel or the combustion air |
Attention is drawn to the following places, which may be of interest for search:
Pilot flame igniters |
This place does not cover:
Torches, e.g. for cutting, brazing, welding or heating |
Attention is drawn to the following places, which may be of interest for search:
Torches, e.g. for brazing or heating |
This place does not cover:
Torches specially adapted for use under water |
This place does not cover:
Torches specially adapted for use under water |
This place does not cover:
Nozzles for torches |
Attention is drawn to the following places, which may be of interest for search:
Injectors for mixing devices | |
Nozzles in general |
Attention is drawn to the following places, which may be of interest for search:
Cutting, scarfing or desurfacing by applying flames |
This place covers:
Devices operating on both combustion air and fuel gas for controlling air to fuel ratio
Attention is drawn to the following places, which may be of interest for search:
Regulation and control of combustion in general |
Attention is drawn to the following places, which may be of interest for search:
Flow mixers in general |
Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:
Preventing flame lift-off | |
Preventing flashback or blowback |
Attention is drawn to the following places, which may be of interest for search:
Protection or supervision of pipe-line systems |
Attention is drawn to the following places, which may be of interest for search:
Baffles or similar flow-disturbing devices |
Attention is drawn to the following places, which may be of interest for search:
Preventing flashback or blowback by use of a retention flame | |
Baffles or similar flow-disturbing devices | |
Preventing flashback or blowback in gas feed lines |
This place does not cover:
Baffles or similar flow-disturbing devices |
This place does not cover:
Gas burner with provisions for a retention flame |
Attention is drawn to the following places, which may be of interest for search:
Using burners for spectroscopy |
This place covers:
Spark-type or glow-type igniters.
Attention is drawn to the following places, which may be of interest for search:
Pilot burners specially adapted for ignition of main burners in furnaces or gas turbines | |
Pilot burners specially adapted for low load or transient conditions, e.g. for increasing stability | |
Regulating or controlling combustion | |
Ignition; Extinguishing devices | |
Sparking plugs |
Attention is drawn to the following places, which may be of interest for search:
Burners for combustion of a gas using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air |
This place covers:
Illustrative example of the subject matter classified in this place:
1a. Burner with flame stabilising diaphragm (side view)
1b. Flame stabilising diaphragm (front view)
In this place, the following terms or expressions are used with the meaning indicated:
diaphragm | a dividing membrane or thin partition, especially in a tube |
This place covers:
Illustrative example of the subject matter classified in this place:
1a.
1b.
Attention is drawn to the following places, which may be of interest for search:
Post-mixing with swirling means | |
Swirling means inside the mixing tube or chamber to improve premixing |
This place covers:
Illustrative example of the subject matter classified in this place:
Attention is drawn to the following places, which may be of interest for search:
Premixing burners with swirling or vortices creating means for fuel or air | |
Swirling means inside the mixing tube or chamber to improve premixing |
This place covers:
Illustrative example of the subject matter classified in this place:
Attention is drawn to the following places, which may be of interest for search:
Premixing burners with swirling or vortices creating means for fuel or air | |
Post-mixing with swirling means |