CPC Definition - Subclass D21F
This place covers:
Methods and devices in the wet end, press section and drying section of a papermaking machine, embossing paper, forming discontinuous sheets of paper.
Attention is drawn to the following places, which may be of interest for search:
Making paper articles | |
Articles for writing or drawing upon | |
Handling webs in general | |
Making textile fabrics from fibers or filamentary material in general | |
Marking, inspecting, seaming or severing textile materials in general | |
Systems for controlling or regulating non-electric variables |
Subgroups and main 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, for example a fiber rearranging device located in the nozzle of a headbox is classified in D21F 1/0018 and D21F 1/028;
- 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:
Section | portion of a paper production machine effecting a certain process step, for example forming, pressing, drying, calendering, coating, etc. |
Yankee | steam heated drying cylinder of large diameter, mainly used for the production of creped tissue paper |
TAD | through air drying process, drying paper webs by passing streams of air therethrough |
This place covers:
Wet end of papermaking machines, starting at the stable section, ending at the transfer/pick up to press section
This place covers:
Controlling and regulating drainage rate, fiber length or degree of refining of a paper pulp suspension.
This place covers:
Devices or altering the distribution of the fibers in the suspension, like for example by pressure pulse or ultrasound, the suspension flowing through the headbox of a papermaking machine.
This place covers:
Screens or fabrics made from plastic materials and useable for forming paper webs in a paper machine by separating fibers from an aqueous suspension or also if usable for drying a paper web in the drying section of a paper machine.
This place covers:
Fabrics comprising two separate layers (paper side layer and machine side layer) and a system of binding yarns interconnecting said layers, the binding yarns can also contribute to the forming of the paper side layer (known as sheet support binding (SSB)).
This place does not cover:
Paper making felts |
Attention is drawn to the following places, which may be of interest for search:
Heat treatment of fabrics |
This place covers:
Devices for altering the distribution of the fibers in the suspension, like for example by pressure pulse or ultrasound, the suspension being already spread on the forming screen.
This place covers:
Head boxes for all kind of paper machines (i.e. Fourdrinier, gapformer, twin- or hybrid-former) if not particularly suitable only for cylinder machines, in which case D21F 1/04 is appropriate.
This place does not cover:
Headboxes of paper machines suitable only for cylinder machines |
Attention is drawn to the following places, which may be of interest for search:
Valves in general |
This place covers:
Devices for injecting additional dilution water, dilution suspension or chemicals into a pulp flow within the headbox.
This place covers:
Regulating the pulp flow into and out of the headbox.
This place covers:
Dilution devices before or in the headbox.
This place covers:
Shaking apparatus for wire and screen cloths, including ultrasound principles.
This place covers:
Shaking apparatus in all type of Fourdrinier, gapformer, twinformer or hybridformer machines.
This place covers:
Shaking apparatus specially adapted for being used in a cylinder machine.
This place covers:
Tilting, raising or lowering mechanisms for wire and screen cloths.
This place covers:
Tilting, raising or lowering mechanisms in all type of Fourdrinier, gapformer, twinformer or hybridformer machines.
This place covers:
Tilting, raising or lowering mechanisms specially adapted for being used in a cylinder machine.
This place covers:
Protecting wire and screen cloths from mechanical damage and contamination, coatings and impregnation agents.
This place covers:
Washing wire or screen cloths or felts.
This place covers:
Wire or screen guiding mechanisms including air border layer seals, air cushion devices, guide rolls, stretching rolls, spreading rolls for the wire or screen.
This place does not cover:
Controlled deflection rolls |
Attention is drawn to the following places, which may be of interest for search:
Registering, tensioning, smoothing or guiding webs |
This place covers:
Watermarking in general, watermarking devices acting on the fibrous suspension or layer while on the forming screen or wire; producing special forming wires or screens for making watermarks; separate watermark elements.
This place covers:
Sheet edge limiting devices; devices for setting the width of the web.
This place covers:
Treatment of white waters or broke, devices and processes in the short circulation of paper machines.
This place covers:
Transferring webs between paper machine sections in general, not only from the wet end to the press section.
This place does not cover:
Transfer belts, bands, felts or fabrics |
This place covers:
Press shells, jackets, covers.
This place covers:
Combinations of individual press elements forming a press section or part of such a section.
This place covers:
Web treatment rolls for press section.
Attention is drawn to the following places, which may be of interest for search:
Rolls, drums, discs or the like |
This place covers:
Suction rolls for forming, pressing and drying sections.
This place covers:
Contact drying using anything except for rolls.
This place covers:
Drying webs on heated cylinders.
This place does not cover:
Drying webs by hot air on a Yankee dryer | |
Drying webs by hot air through perforated cylinders |
This place covers:
Construction details of cylinders for drying webs of paper, e.g. material of cylinder, production process like welding or casting, or isolation.
Attention is drawn to the following places, which may be of interest for search:
Details of heat-exchange rotary drums or rollers in general |
This place covers:
Drying sections including suction or blowing devices, for example including a single-tier drying group.
This place covers:
Drying paper webs on loops formed by a series of rods, e.g. GB 820910
This place covers:
Drying paper webs by hot air.
This place does not cover:
Blow-on drying, impingement on cylinders |
This place covers:
Steam blow boxes arranged in the paper machine.
This place does not cover:
Web conditioning devices in calenders | |
Damping devices |
This place covers:
Transfer belts, bands, felts or fabrics.
This place covers:
Complete machines (i.e. at least two sections combined) for making paper or for producing air-layed webs.
This place does not cover:
Complete machines (i.e. at least two sections combined) comprising a coating section combined with any other section |
This place does not cover:
Machines and processes for making tissue papers |
This place covers:
Methods for making patterned paper, e.g. non-planar surfaces or colour variations as obtained directly by the web-forming process.
Attention is drawn to the following places, which may be of interest for search:
Details of the base fabric of imprinting, embossing, texturing belts | |
Embossing | |
Crêping | |
Patterned paper |
This place does not cover:
Machines and processes for making tissue papers |
This place covers:
Machines and processes specially adapted for forming tissue papers.
This place covers:
Making hand-made paper, restoration of paper.