CPC Definition - Subclass F23H

Last Updated Version: 2021.02
GRATES (inlets for fluidisation air for fluidised bed combustion apparatus F23C 10/20); CLEANING OR RAKING GRATES
Definition statement

This place covers:

All details of combustion grates, including all relevant accessories and peripheral devices such as driving mechanisms or cooling arrangements for example, independently from the type of solid fuel which is supported and burned on the grate.

Limiting references

This place does not cover:

Inlets for fluidisation air for fluidised bed combustion apparatus

F23C 10/20

Application-oriented references

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:

Arrangements or mountings of grates in incinerators

F23G 5/002

Arrangements or mountings of grates in stoves or ranges

F24B 13/02

Informative references

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

Arrangements of drying grates in incinerators

F23G 5/05

Details of drying grates


Details of cooling grates in furnaces or ovens in general

F27D 15/0213

Special rules of classification

Subgroups F23H 7/12-F23H 7/18 are not used; all inclined or stepped grates should be classified either in subgroups F23H 7/08 or F23H 7/10.

Indexing Codes F23H 2700/001-F23H 2700/009 are not used for classification purpose.

Glossary of terms

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


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.


means any solid combustion residues, for example remaining in the fuel bed or suspended in the flue gases


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


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

Flue gases

any gaseous products of combustion


a perforated surface, e.g. a grid which supports or delimits a bed of burning fuel and serves to supply primary air

Synonyms and Keywords

In patent documents, the following words/expressions are often used with the meaning indicated:


"combustion apparatus".


"combustion apparatus".

Grates rocked as a whole
Definition statement

This place covers:

All grates somehow moved as a whole, thus including also vibrating grates.