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GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (using such products for specific purposes, see the relevant classes for the purposes; chemical aspects of gas production C06D 5/00; gas-turbine plants characterised by the arrangement of the combustion chamber in the plant F02C 3/14; arrangement of afterburners in jet-propulsion plants F02K 3/10; combustion chambers of rocket-engine plants F02K 9/00)
Definition statement
This subclass/group covers:

Combustion chambers that are specially adapted for generation of gaseous combustion products of high pressure or high velocity, and therefore suitable for use as a source of motive power rather than merely a source of heat. Examples of such special adaptations are:

  • Specialised configuration in order to be incorporated in a power plant, for example as a combustion chamber between the compressor stage and the turbine stage of a gas turbine plant, or as an afterburner in a jet engine;
  • Specialised construction for tolerating high temperatures, for example film cooling or diffusion cooling;
  • Specialised arrangements for supplying combustion air, cooling air or dilution air;
  • Specialised arrangements for fuel injection.

Methods of combustion in combustion chambers that are specially adapted for generation of combustion products of high pressure or high velocity.

Relationship between large subject matter areas

This subclass is to be seen as an application place in relation to the function-oriented aspects covered by other subclasses of F23. If a method or apparatus is of general interest for combustion it should be classified in other subclasses of F23, for example subclasses F23C, methods or apparatus for combustion using fluent fuel and F23D, burners. If a detail is of general interest for combustion apparatus it should also be classified in other subclasses of F23, for example subclasses F23K, feeding fuel to combustion apparatus or F23N, regulating or controlling combustion. It is sometimes difficult to decide whether an apparatus or a detail is specially adapted or not. In doubtful situations classification should therefore be made in both this subclass and other subclasses of F23.

This subclass covers the configuration of single combustion chambers or flame tubes, or the mutual, e.g. annular arrangement of several combustion chambers or flame tubes. The incorporation or arrangement of combustion chambers within a power plant is classified in the place for the power plant as a whole, for example in subclasses F02C, gas turbine plants or F02K, jet propulsion plants.

When the control of the combustion is integrated in the control system of an entire power plant it is classified in the place for the control system as a whole, for example in groups F02C 9/00 or F02K 3/08.

References relevant to classification in this subclass
This subclass/group does not cover:
Fluidised bed combustion chambers specially adapted for operation at super-atmospheric pressures

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:

Combined gas turbine and steam turbine plants
Gas turbine plants
Combustion-product positive-displacement engine plants
Jet-propulsion plants
Combustion chambers for rocket engine plants, i.e. plants carrying both fuel and oxidant therefor
Starting of engines by supplying pressure fluid generated directly by combustion
Informative references
Attention is drawn to the following places, which may be of interest for search:
Generation of pressure gas by chemical means
Gas turbines
Combustion chambers for internal combustion engines, combustion in internal combustion engines
Cooling of gas turbine plants
Mounting or supporting of gas turbine plants, accommodating heat expansion or creep in gas turbine plants
Arrangement of seals in gas turbine plants
Cylinders for combustion engines
Supplying combustion engines in general with combustible mixtures or constituents thereof
Steam generation using combustion under pressure substantially exceeding atmospheric pressure
Methods or apparatus for combustion using fluent fuel in general
Air supply to combustion chambers in general
Burners in general
Feeding fuel to combustion apparatus in general
Details of combustion chambers in general
E.g. walls
Regulating or controlling combustion in general
Igniting
Special rules of classification within this subclass

In this subclass methods are classified in the groups that cover the apparatus used.

If the invention deals also with methods of controlling the combustion process, then classification in F23N and/or F23N shall be considered. In this case, use also code F23N 2041/20.

When classifying in this subclass, add also codes F23R 2900/00001-F23R 2900/03342.

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 expression "secondary air" covers "tertiary air" etc.
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
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 a combustion apparatus where the reaction takes place between air and fuel
Flame tube
The portion of a combustion chamber downstream of the zone where fuel and primary air are mixed.
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
Retention flame
a small flame that is kept alight in order to maintain the uninterrupted operation of a more powerful burner
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
Continuous combustion chambers using liquid or gaseous fuel
Definition statement
This subclass/group covers:

Continuous combustion chambers using liquid or gaseous fuel.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Burners
Cooling burner parts in gaseous fuel burners
Cooling burner parts in liquid fuel burners
Indexing Code for burner cooling in general
Ignition in gas turbine plants
Pilot flame igniters
{Wall structures (F23R 3/02 and F23R 3/007 take precedence) }
References relevant to classification in this group
This subclass/group does not cover:
Combustion chambers characterised by the air or gas flow configuration
Combustion chambers constructed mainly of ceramic components
characterised by the air-flow or gas-flow configuration (reverse- flow combustion chambers F23R 3/54; cyclone or vortex type combustion chambers F23R 3/58)
References relevant to classification in this group
This subclass/group does not cover:
Reverse-flow combustion chambers
Cyclone or vortex type combustion chambers
for primary air (F23R 3/06, F23R 3/045 take precedence)
References relevant to classification in this group
This subclass/group does not cover:
Arrangement of apertures along the flame tube
Air inlet arrangements using pipes
{having fuel-air premixing devices (F23R 3/30 takes precedence) }
References relevant to classification in this group
This subclass/group does not cover:
Combustion chambers wherein the fuel supply means comprise fuel pre-vaporising devices
Combustion chambers comprising a {single} tubular flame tube within a tubular casing (reverse-flow combustion chambers F23R 3/54)
References relevant to classification in this group
This subclass/group does not cover:
Reverse-flow combustion chambers
Annular combustion chambers
Multiple tubular flame tubes within a common casing
Continuous combustion chambers using solid or pulverulent fuel
Definition statement
This subclass/group covers:

High pressure or high velocity combustion chambers using solid, e.g. lumps of wood, or pulverulent fuel . e.g. pulverized coal or biomass.

Intermittent or explosive combustion chambers
Definition statement
This subclass/group covers:

High pressure or high velocity combustion chambers wherein the combustion is pulsating or resonating type, e.g. pulse detonation

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Last Modified: 10/11/2013