F23C - Definition

Definition statement

This subclass covers:

General function-oriented aspects of methods and apparatus for combustion of

• Fluid fuels or solid fuels suspended in air, alone or in combination with other fluid or non-fluid fuels;
• Fluid fuels or solid fuels suspended in air, alternately with other fuels;
• Pulverised solid fuel suspended in a stream of air or other gas (e.g. combustion in fluidised beds or combustion of pulverised fuel using burners where the fuel is transported into the combustion chamber by an air stream);
• Solid fuel suspended in a liquid (e.g. combustion of coal-water slurry).

Relationship between large subject matter areas

Relationship between this subclass and application subclasses of class F23

F23G (Cremation furnaces; Consuming waste by combustion) is to be seen as an application place in relation to the function-oriented aspects of combustion covered by this subclass. In case of doubt, classification should be made in both subclasses, or in both F23G and detail subclasses of class F23.

Classification is made in F23C if the methods or apparatus are

• of general interest for combustion of different types of fluid fuel or solid fuel suspended in air, for example not specially adapted for a particular fuel; or
• specially adapted for fluid fuels or solid fuels suspended in air other than those provided for in F23G (see the list below), for example a "normal" commercial fuel, such as oil, natural gas or pulverised coal.

Classification is made in F23G if the methods or apparatus are specially adapted for combustion of the following types of substances:

• Fuels, e.g. waste, presenting particular fuel-related environmental problems requiring specially adapted methods or apparatus for combustion, for example toxic, explosive, radioactive or corrosive fuels;
• Waste having a special physical form requiring specially adapted methods or apparatus for combustion, for example packaged waste;
• Low-grade fuels presenting particular problems of combustion requiring specially adapted methods or apparatus for combustion, for example contaminated oil or gas of low heating value.

F23R (Generating combustion products of high pressure or high velocity) is also to be seen as an application place in relationship to this subclass.

Classification is made in F23R if the apparatus or method is specially adapted for generating combustion products of high pressure or high velocity.

Relationship between this subclass and other application places

Combustion is often used for the purpose of heating or performing different operations. Apparatus for combustion can be self-contained devices, but are often part of, or used in connection with, heat-consuming apparatus, such as heating boilers. This subclass is therefore related to several places providing for uses of heat. In many of these fields the combustionapparatus can be considered a detail of a bigger entity. A non-exhaustive list of examples of such classes or subclasses will be found under the heading "Informative references" below.

Combinations of combustion apparatus with other apparatus, where the combustion apparatus can be seen as a detail of the complete apparatus (for example of a steam boiler), are classified as a whole, in the place for the other apparatus. Additional classification is made in this subclass only if features relating to the combustion apparatus per se are of interest apart from its application.

Relationship between this subclass and detail subclasses of class F23

Subclass F23D covers burners per se, as defined in the section "Glossary" below. Classification is made in F23C if the subject matter to be classified, in addition to a burner, includes further features that are of interest, such as a particular form of combustion chamber or a particular arrangement of burners in a combustion chamber. Air supply means that are arranged in immediate connection with the fuel-feeding conduit of a burner, for example concentric with it, should be considered to be part of the burner. Means for feeding air otherwise than in immediate connection with the fuel-feeding conduit of a burner are classified in F23C or F23L, for example arrangements for feeding secondary air at points distant from a burner.

Subclasses F23J-F23Q are to be seen as detail places in relation to this subclass. Classification is made in this subclass if the apparatus as a whole is of interest, or if a detail is of use only for a particular type of combustion apparatus and not specifically provided for in any of subclasses F23J-F23Q. If a detail of a combustion apparatus is of interest, classification is made in the relevant subclass providing for such matter.

References relevant to classification in this subclass

This subclass does not cover:

Informative references

Attention is drawn to the following places, which may be of interest for search:

Places for details of general applicability for combustion apparatus

Other places

Special rules of classification

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

Glossary of terms

In this subclass, the following terms or expressions are used with the meaning indicated:

Synonyms and Keywords

In patent documents the following abbreviations are often used:

In patent documents the expression "burner" is often used with the meaning of "combustion apparatus".