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AIR SUPPLY; DRAUGHT-INDUCING; SUPPLYING NON-COMBUSTIBLE LIQUID OR GAS (air-supply arrangements for fluent fuels F23C; dampers and throat restrictors for open fire-places F24; air inlet valves for open fire fronts F24)
Definition statement
This subclass/group covers:

Supply of air or non-combustible gases or liquids to combustion apparatus in general, for example:

  • Blast-producing apparatus before the fire, for example fans or induction apparatus;
  • Passages or nozzles for delivering air to combustion chambers;
  • Methods or devices for supplying steam or oxygen to the fire;
  • Methods or devices for heating of combustion air before supply to the combustion chamber, for example by heat exchange with flue gases;
  • Special adaptations of valves or dampers for controlling combustion air supply or flue gas draught in combustion apparatus in general;
  • Methods or devices for inducing draught in combustion apparatus, for example exhaust fans or exhaust induction apparatus;
  • Tops for chimneys or ventilation shafts;
  • Terminals for flues.
Relationship between large subject matter areas

Combustion apparatus

This subclass is the general place for methods and apparatus for supply of air to combustion apparatus.

The incorporation of air supply means as an integrated part of an entire combustion apparatus, for example the disposition of primary and secondary air ports in relation to other components, is classified in the place for the combustion apparatus as a whole, in F23B, F23C or F23G.

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, and are thus classified in F23D. Other means for feeding air that are specially adapted for combustion of liquid fuel, gaseous fuel or pulverised fuel suspended in air are classified in F23C 7/00 or F23C 10/20.

Blast-producing, draught-inducing

This subclass is an application-oriented place for the arrangement of fans, inductors or other pumps in combustion apparatus for the purpose of inducing blast or draught. The integration of such devices in systems for control of combustion, for example together with sensors and actuators, is covered by F23N.

Fans and other pumps per se are classified in class F04, for examples see the section "Informative references" below.

Valves and dampers

This subclass is an application-oriented place for valves and dampers that are specially adapted for controlling air supply or draught of combustion apparatus. The integration of such devices in systems for control of combustion, for example together with sensors and actuators, is covered by F23N.

Valves or dampers that are specially adapted for controlling air supply or draught of domestic stoves are classified in F24B or F24C, for examples see the section "References relevant to classification in this subclass" below.

Valves and dampers in general are classified in F16K.

Heating of combustion air

This subclass is an application-oriented place for the heat exchange apparatus that is specially adapted for use in combustion apparatus for the purpose of heating combustion air. Heat exchangers in general are classified in class F28, for examples see the section "Informative references" below.

References relevant to classification in this subclass
This subclass/group does not cover:
Returning flue gases to the combustion chamber of combustion apparatus for solid fuel
Returning flue gases to the combustion chamber of combustion apparatus for liquid or gaseous fuel or pulverised solid fuel suspended in air
Grates for combustion apparatus
Supplying chemicals to fires
Firebridges for delivery of air or steam to combustion apparatus
Cooling of casings, lining or walls of combustion chambers
Doors specially adapted for combustion chambers
Baffles or deflectors in air inlets of combustion chambers
Baffles or deflectors for air or combustion products with air-supply passages

Examples of places where the subject matter of this class is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Steam generators
Air supply specially adapted for combustion apparatus for liquid, gaseous or pulverised fuel
Supply of fluidisation air for fluidised bed combustion apparatus
Burners
Burners where spraying of liquid fuel is induced by a gaseous medium
Gas burners specially adapted for use with means for pressurising the combustion air
Regulating or controlling air supply or draft
Systems for regulating or controlling combustion
Air inlet arrangements for combustion chambers for generating combustion products of high pressure or high velocity, e.g. for gas turbine combustion chambers
Draught control dampers for solid fuel stoves with open fires
Air supply in solid fuel stoves with open fires
Hoods for solid fuel stoves with open fires
Combustion-air or flue gas circulation in or around solid fuel stoves
Stoves for combustion of gaseous or liquid fuels, or for two or more different fuels
Fluid heaters, e.g. water or air heaters for central heating
Informative references
Attention is drawn to the following places, which may be of interest for search:
Positive displacement air pumps in general
Fans in general
Jet pumps in general
Valves in general
Methods or apparatus for combustion using solid fuel
Methods or apparatus for combustion using fluid fuel
Domestic stoves or ranges for solid fuels
Air humidification
Air flow control members for ventilation or air conditioning
Heat exchangers in general
Special rules of classification within this subclass

In this subclass, the first place priority rule is applied, i.e. at each hierarchical level, classification is made in the first appropriate place.

When classifying in this subclass, add also codes F23L 2900/00001-R23L900/17022.

Codes F23L 2700/001-F23L 2700/002 are not used.

Glossary of terms
In this subclass/group, 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
Primary air
air supplied to the burning fuel in order to liberate combustible gases
Secondary air
air supplied to the combustible gases liberated by the primary air in order to complete their combustion. The term "secondary air" covers "tertiary air" etc.
Ash
means any solid combustion residues, for example remaining in the fuel bed or suspended in the flue gases
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
Combustion
means the direct combination of oxygen gas, e.g. in air, and a burnable substance
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 zone
the part of the apparatus where the reaction takes place between air and fuel
Firebridge
a low wall separating the fuel bed from adjacent flue gas passages in apparatus for combustion of solid fuel, for example in reverberatory furnaces or fire-tube boilers
Flue gases
any gaseous products of combustion
Grate
a perforated surface, e.g. a grid, which supports or delimits a bed of burning fuel and serves to supply primary air
Passages or apertures for delivering primary air for combustion
Definition statement
This subclass/group covers:

Passages or apertures for delivering primary air for combustion.

Arrangements of valves or dampers before the fire
Definition statement
This subclass/group covers:

Arrangements of valves or dampers before the fire.

Blast-producing apparatus before the fire
Definition statement
This subclass/group covers:

Blast-producing apparatus before the fire.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements of fans or blowers per se
F04
Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam
Definition statement
This subclass/group covers:

Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam.

Passages or apertures for delivering secondary air for completing combustion of fuel
Definition statement
This subclass/group covers:

Passages or apertures for delivering secondary air for completing combustion of fuel.

Arrangements of valves or dampers after the fire
Definition statement
This subclass/group covers:

Arrangements of valves or dampers after the fire.

Construction of valves or dampers for controlling air supply or draught (in general F16K)
Definition statement
This subclass/group covers:

Construction of valves or dampers for controlling air supply or draught.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Valves in general
pivoted about a single axis but having not other movement (formed as linked slats each pivoted about an axis F23L 13/08)
References relevant to classification in this group
This subclass/group does not cover:
Valves formed as linked slats each pivoted about an axis
Heating of air supplied for combustion
Definition statement
This subclass/group covers:

Heating of air supplied for combustion.

Inducing draught
Definition statement
This subclass/group covers:

Inducing draught.

Subject matter not provided for in other groups of this subclass
Definition statement
This subclass/group covers:

Subject matter not provided for in other groups of this subclass.

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Last Modified: 10/11/2013