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TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
Definition statement
This subclass 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.

References relevant to classification in this subclass
This subclass does not cover:

Methods for making pulp by refining wood chips

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

Discs for beating or refining in general

Cyclones in general

Special rules of classification within this subclass

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.
Glossary of terms
In this subclass, 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

Methods of beating or refining; Beaters of the Hollander type (knotter screens D21F)
Definition statement
This group covers:

Methods of beating and refining of pulp fibers in general.

References relevant to classification in this subclass
This group does not cover:

knotter screens

{Methods of beating or refining including disperging or deflaking}
Definition statement
This subgroup 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.

{Disc mills}
Definition statement
This subgroup covers:

Disc mills only if particularly suitable for disperging or deflaking.

{Discs}
Definition statement
This subgroup covers:

Discs for disc mills only if particularly suitable for disperging or deflaking.

Methods of beating; Beaters of the Hollander type
Definition statement
This subgroup 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.

Other mills or refiners
Definition statement
This subgroup 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.

References relevant to classification in this group

Places in relation to which this group is residual:

Beaters

Jordans

Ball or rod mills

Disc mills

Hammer mills

Washing the fibres
Definition statement
This subgroup covers:

Equipment and methods for washing and dewatering pulp.

References relevant to classification in this subclass
This subgroup does not cover:

Washing pulp from cooking liquors

Recovering fibrous materials from suspensions in the paper machine approach system or white water

Purification of the pulp suspension by mechanical means; Apparatus therefor (centrifuges, cyclones B04)
Definition statement
This group 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.

References relevant to classification in this subclass
This group does not cover:

centrifuges, cyclones

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

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

Degasification of liquids in general

{Forming fibrous aggregates}
Definition statement
This subgroup 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.

with the aid of centrifugal force
Definition statement
This subgroup covers:

Purification, sorting and fractioning methods using centrifugal force.

Equipment for performing the methods.

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

cyclones in general

De-aeration of paper stock
Informative references
Attention is drawn to the following places, which may be of interest for search:

Degassing of liquids in general

Subject matter not provided for in other groups of this subclass
Definition statement
This group 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.

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Last Modified: 10/11/2013