CPC Definition - Subclass D21D
This place covers:
Beating and refining methods and equipments for fibrous materials; purification methods and equipments for pulp suspensions acting by mechanical means, i.e. straining, screening, centrifugal cleaning, sorting, de-aeration; tanks for storing or agitating pulp.
This place does not cover:
Methods for making pulp by refining wood chips |
Attention is drawn to the following places, which may be of interest for search:
Subgroups and head groups.
If a document concerns embodiments which are covered by several subgroups dependent on a higher hierarchy group, the following rules apply:
- the specific technical information relevant for some of the subgroups is classified in all said subgroups;
- if relevant, the structural association (e.g. the combination) of the elements covered by the subgroups is classified in the head group;
- analogously, if generic technical information common to all of the subgroups is disclosed and only schematic embodiments of the specific subgroup embodiments are represented, the documents is classified in the head group only.
In this place, the following terms or expressions are used with the meaning indicated:
Hollander | special historical equipment for beating fibrous suspensions, see definition statement of D21D 1/02 |
Beating | treatment of fibrous suspensions in Hollander type equipment in order to fibrillate, shorten or flexibilize fibers |
Refining | treatment of fibrous suspensions for the same purpose in all other types of equipment |
Jordan | refiner having a frusto-conical rotor revolving inside a complimentary stator |
Bed plate | stator of Hollander or Jordan devices |
This place covers:
Disperging (i.e. separating rather small impurities sticking to the surface of a fiber) or deflaking (i.e. separating flakes or flocs formed by fibers into the individual fibers again) methods and equipments for fibrous materials.
This place covers:
Disc mills only if particularly suitable for disperging or deflaking.
This place covers:
Discs for disc mills only if particularly suitable for disperging or deflaking.
This place covers:
Treatment in Hollander equipment, i.e. in a device using at least one wheel like beating rotor (roll) equipped with beating tools (knifes) revolving in a trough having a beating stator (bed plate), also equipped with beating tools (knifes), in which trough the suspension is circulated to pass multiple times through the beating zone formed between the rotor and the stator.
This place covers:
Refiners or mills not provided before, for example cylindrical rotors and stators, belt refiners, kneaders causing a refining action, compression refiners, planetary gear like equipment.
This place covers:
Equipment and methods for washing and dewatering pulp.
This place covers:
Purification methods and equipments for pulp suspensions acting by mechanical means, i.e. straining, screening, centrifugal cleaning, sorting, de-aeration; tanks for storing or agitating pulp.
This place does not cover:
centrifuges, cyclones |
Attention is drawn to the following places, which may be of interest for search:
Degasification of liquids in general | |
Other filters with filtering elements stationary during filtration, e.g. pressure or suction filters in general | |
Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like, in general |
This place covers:
Forming fiber bundles by agitating suspensions; magnetic deinking of suspensions by attaching ink particles in the paper pulp to a magnetic carrier material with the help of an agglomeration agent.
This place covers:
Purification, sorting and fractioning methods using centrifugal force.
Equipment for performing the methods.
Attention is drawn to the following places, which may be of interest for search:
Degassing of liquids in general |
This place covers:
Subject-matter that fits within the scope of the subclass but is not covered by any of the other groups, such as for example fractioning methods, methods dividing the total suspension stream in portions, not for cleaning purposes, but for obtaining fibre fractions of different properties, e.g. separating longer from shorter fibres, finer from coarser fibres; and treating at least one of these portions differently from remaining portion(s) in subsequent process steps.