CPC Definition - Subclass B01F

Last Updated Version: 2022.01
Definition statement

This place covers:

Agitation and/or homogenization of products formed by a combination of two or more components with the purpose of obtaining an homogeneous composition or homogeneous conditions in the mass of material.

Stirring of a single material with the purpose of obtaining homogeneous conditions in the mass of material.

This subclass covers the mixing, agitation and homogenization of materials, irrespective of the application in which it is produced, whenever the device and/or method is directed to achieve said desired effect.

Limiting references

This place does not cover:

Disinfection, sterilisation or deodorisation of air

A61L 9/00


B01D 1/00


B01D 3/00

Granulation (with or without coating)

B01J 2/00


B01J 19/00

Crushing, pulverising, disintegrating




Spraying, atomising

B05B, B05C

Air-conditioning, air-humidification, ventilation




Heat-exchange apparatus in which the heat-exchange media are contacted, e.g. cooling towers


Special rules of classification

In general, devices and methods in which agitation and or contact of materials is produced, the object of said agitation/contact being different than for obtaining an homogeneous mixture (e.g. mass transfer devices and processes, a mere contact of two or more different materials, devices or processes in which agitation/homogenization is intrinsic to the process per se but it is not the primary purpose) are not classified in this subclass.

As a general rule, the following information is to be classified in its whole extent:

What is mixed, i.e. the phases of materials being mixed: groups B01F 21/00 and B01F 23/00.

Auxiliary information: groups B01F 35/00.

The use of substances used as emulsifying, wetting, dispersing or foam-producing agents is normally only classified in C09K 23/00, except when the related devices for mixing are also disclosed.

With regard to the phases to be mixed, the following is to be observed:

  • when only a general reference to the phases is indicated, only the Indexing Codes B01F 21/00 and B01F 23/00 are used;
  • if reference is made to the use of the device for any kind of mixtures, it is not classified in B01F 21/00, B01F 23/00, B01F 21/00 or B01F 23/00;
  • when the application is of relevance (i.e. the type of product produced is claimed or the device is claimed for making a specific product) then it is also classified in the corresponding application field;
  • if the possible application or applications are only mentioned in a generic way (i.e. as possible uses of the device) then the corresponding KW is used instead.

With regard to the way of mixing all parts of the device which are used for mixing are classified in its corresponding group. When more than one mixing device form part of the apparatus, the device is also classified in B01F 33/80.

With regard to the auxiliary information the corresponding general fields, if they exist, take precedence. If the only possible classification symbol which can be allocated is a symbol in the group B01F 35/00 then it has to be classified in the general field (e.g. if it can only be classified in B01F 35/90 then it is a clear indication that it has to be classified in F28).

Glossary of terms

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


stirring of a single material