1. CPC Sections
  2. CPC Section D
  3. CPC Class D21
  4. CPC Subclass D21F
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Version: 2024.08
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CPC
COOPERATIVE PATENT CLASSIFICATION
​
D21F
PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON [2018-08]
WARNING

  • In this subclass non-limiting references (in the sense of paragraph 39 of the Guide to the IPC) may still be displayed in the scheme.
D21F 1/00
Wet end of machines for making continuous webs of paper [2013-01]
D21F 1/0009
.
{Regulating the freeness of the pulp} [2013-01]
D21F 1/0018
.
{Devices for dispensing fibres in a fluid} [2013-01]
D21F 1/0027
.
{Screen-cloths} [2013-01]
D21F 1/0036
. .
{Multi-layer screen-cloths} [2013-01]
D21F 1/0045
. . .
{Triple layer fabrics} [2013-01]
D21F 1/0054
. .
{Seams thereof} [2013-01]
D21F 1/0063
. .
{Perforated sheets} [2013-01]
D21F 1/0072
. .
{Link belts} [2013-01]
D21F 1/0081
. .
{with single endless strands travelling in generally parallel convolutions} [2013-01]
D21F 1/009
.
{Fibre-rearranging devices} [2013-01]
D21F 1/02
.
Head boxes of Fourdrinier machines [2013-01]
D21F 1/022
. .
{Means for injecting material into flow within the headbox} [2013-01]
D21F 1/024
. .
{Details of the feed chamber} [2013-01]
D21F 1/026
. .
{Details of the turbulence section} [2013-01]
D21F 1/028
. .
{Details of the nozzle section} [2013-01]
D21F 1/04
.
Head boxes of cylinder machines [2013-01]
D21F 1/043
. .
{with immersed cylinders} [2013-01]
D21F 1/046
. .
{with non-immersed cylinder} [2013-01]
D21F 1/06
.
Regulating pulp flow [2013-01]
D21F 1/065
. .
{Shock-absorbing devices} [2013-01]
D21F 1/08
.
Regulating consistency [2013-01]
D21F 1/10
.
Wire-cloths [2024-05]
D21F 1/105
. .
{Multi-layer wire-cloths} [2013-01]
D21F 1/12
. .
Seams thereof [2013-01]
D21F 1/14
. . .
welded [2013-01]
D21F 1/16
. . .
sewn [2013-01]
D21F 1/18
.
Shaking apparatus for wire-cloths and associated parts [2013-01]
D21F 1/20
. .
in Fourdrinier machines [2017-08]
D21F 1/22
. .
in cylinder machines [2013-01]
D21F 1/24
.
Tilting, raising, or lowering mechanisms for wire-cloths [2013-01]
D21F 1/26
. .
in Fourdrinier machines [2013-01]
D21F 1/28
. .
in cylinder machines [2013-01]
D21F 1/30
.
Protecting wire-cloths from mechanical damage [2013-01]
D21F 1/32
.
Washing wire-cloths or felts [2013-01]
D21F 1/325
. .
{with reciprocating devices} [2013-01]
D21F 1/34
.
Construction or arrangement of spraying pipes [2013-01]
D21F 1/345
. .
{Spraying-pipe cleaners} [2013-01]
D21F 1/36
.
Guiding mechanisms [2024-05]
D21F 1/365
. .
{for controlling the lateral position of the screen} [2013-01]
D21F 1/38
. .
Pads [2013-01]
D21F 1/40
. .
Rolls [2013-01]
D21F 1/42
. .
Jets [2013-01]
D21F 1/44
.
Watermarking devices [2013-01]
D21F 1/46
. .
Dandy rolls [2013-01]
D21F 1/48
.
Suction apparatus (suction rolls D21F 3/10) [2013-01]
D21F 1/483
. .
{Drainage foils and bars} [2013-01]
D21F 1/486
. . .
{adjustable} [2013-01]
D21F 1/50
. .
Suction boxes with rolls [2013-01]
D21F 1/52
. .
Suction boxes without rolls [2013-01]
D21F 1/523
. . .
{Covers thereof} [2013-01]
D21F 1/526
. . . .
{consisting of endless moving belts} [2013-01]
D21F 1/54
.
Skimming devices, e.g. froth ledges [2013-01]
D21F 1/56
.
Deckle frame arrangements [2013-01]
D21F 1/58
.
Deckle straps [2013-01]
D21F 1/60
.
Cylinder moulds [2013-01]
D21F 1/62
.
Sand traps [2013-01]
D21F 1/64
.
Magnetic separators [2013-01]
D21F 1/66
.
Pulp catching, de-watering, or recovering; Re-use of pulp-water [2013-01]
D21F 1/68
. .
using hydrocyclones [2024-05]
D21F 1/70
. .
by flotation [2013-01]
D21F 1/72
. .
using funnels [2013-01]
D21F 1/74
. .
using cylinders [2013-01]
D21F 1/76
. . .
with suction [2013-01]
D21F 1/78
. . .
with pressure [2013-01]
D21F 1/80
. .
using endless screening belts [2013-01]
D21F 1/82
. .
adding fibre agglomeration compositions [2013-01]
D21F 2/00
Transferring continuous webs from wet ends to press sections [2024-05]
D21F 3/00
Press section of machines for making continuous webs of paper [2013-01]
D21F 3/02
.
Wet presses [2013-01]
D21F 3/0209
. .
{with extended press nip} [2013-01]
D21F 3/0218
. . .
{Shoe presses} [2013-01]
D21F 3/0227
. . . .
{Belts or sleeves therefor} [2013-01]
D21F 3/0236
. . . . .
{manufacturing methods} [2013-01]
D21F 3/0245
. . . . .
{Means for fixing the sleeve to the roller end} [2013-01]
D21F 3/0254
. . .
{Cluster presses, i.e. presses comprising a press chamber defined by at least three rollers} [2013-01]
D21F 3/0263
. . . .
{Sealing arrangements therefor} [2013-01]
D21F 3/0272
. .
{in combination with suction or blowing devices} [2013-01]
D21F 3/0281
. .
{in combination with a dryer roll} [2013-01]
D21F 3/029
. .
{using special water-receiving belts} [2013-01]
D21F 3/04
. .
Arrangements thereof [2013-01]
D21F 3/045
. . .
{including at least one extended press nip} [2013-01]
D21F 3/06
. .
Means for regulating the pressure [2013-01]
D21F 3/08
. .
Pressure rolls [2013-01]
D21F 3/083
. . .
{perforated} [2013-01]
D21F 3/086
. . .
{having a grooved surface} [2013-01]
D21F 3/10
. .
Suction rolls, e.g. couch rolls [2013-01]
D21F 3/105
. . .
{Covers thereof} [2013-01]
D21F 5/00
Dryer section of machines for making continuous webs of paper [2013-01]
D21F 5/001
.
{Drying webs by radiant heating} [2013-01]
D21F 5/002
. .
{from infrared-emitting elements} [2023-08]
D21F 5/003
. .
{Shutter means} [2013-01]
D21F 5/004
.
{Drying webs by contact with heated surfaces or materials} [2013-01]
D21F 5/005
. .
{in a fluid bed} [2013-01]
D21F 5/006
.
{Drying webs by using sonic vibrations} [2013-01]
D21F 5/007
.
{Drying webs by contact with sorbent bodies} [2013-01]
D21F 5/008
.
{Drying webs by direct contact with gas flames} [2013-01]
D21F 5/009
.
{Drying webs by centrifugal treatment} [2013-01]
D21F 5/02
.
Drying on cylinders [2013-01]
D21F 5/021
. .
{Construction of the cylinders} [2013-01]
D21F 5/022
. .
{Heating the cylinders} [2013-01]
D21F 5/024
. . .
{using electrical means} [2013-01]
D21F 5/025
. . .
{using combustion gases} [2013-01]
D21F 5/027
. . .
{using a heat-transfer fluid between the heating means and the cylinder shell} [2013-01]
D21F 5/028
. . .
{using steam} [2013-01]
D21F 5/04
. .
on two or more drying cylinders [2013-01]
D21F 5/042
. . .
{in combination with suction or blowing devices} [2013-01]
D21F 5/044
. . . .
{using air hoods over the cylinders} [2013-01]
D21F 5/046
. . . .
{using pocket ventilation systems} [2013-01]
D21F 5/048
. . .
{in combination with other heating means} [2013-01]
D21F 5/06
. .
Regulating temperature [2013-01]
D21F 5/08
. .
Arrangement of steam points in the cylinders [2013-01]
D21F 5/10
. .
Removing condensate from the interior of the cylinders [2013-01]
D21F 5/12
.
Festoon drying [2013-01]
D21F 5/14
.
Drying webs by applying vacuum [2013-01]
D21F 5/143
. .
{through perforated cylinders} [2013-01]
D21F 5/146
. .
{Vacuum seals} [2013-01]
D21F 5/16
.
Drying webs by electrical heating [2013-01]
D21F 5/162
. .
{Resistance heating} [2013-01]
D21F 5/165
. .
{Inductive heating; Capacitive heating} [2013-01]
D21F 5/167
. .
{Microwave heating} [2013-01]
D21F 5/18
.
Drying webs by hot air [2013-01]
D21F 5/181
. .
{on Yankee cylinder} [2013-01]
D21F 5/182
. .
{through perforated cylinders} [2013-01]
D21F 5/184
. . .
{Surfaces thereof} [2013-01]
D21F 5/185
. .
{Supporting webs in hot air dryers} [2013-01]
D21F 5/187
. . .
{by air jets} [2013-01]
D21F 5/188
. . . .
{Blowing devices} [2013-01]
D21F 5/20
.
Waste heat recovery [2013-01]
D21F 7/00
Other details of machines for making continuous webs of paper [2013-01]
D21F 7/001
.
{Wire-changing arrangements} [2013-01]
D21F 7/003
.
{Indicating or regulating the moisture content of the layer} [2013-01]
D21F 7/005
.
{Wire-tensioning devices} [2013-01]
D21F 7/006
.
{Cutting the edges of the paper-web} [2013-01]
D21F 7/008
.
{Steam showers} [2013-01]
D21F 7/02
.
Mechanical driving arrangements [2013-01]
D21F 7/04
.
Paper-break control devices [2013-01]
D21F 7/06
.
Indicating or regulating the thickness of the layer; Signal devices [2013-01]
D21F 7/08
.
Felts [2013-01]
D21F 7/083
. .
{Multi-layer felts} [2013-01]
D21F 7/086
. .
{Substantially impermeable for transferring fibrous webs} [2013-01]
D21F 7/10
. .
Seams thereof [2013-01]
D21F 7/12
. .
Drying [2013-01]
D21F 9/00
Complete machines for making continuous webs of paper [2013-01]
D21F 9/003
.
{of the twin-wire type} [2013-01]
D21F 9/006
. .
{paper or board consisting of two or more layers} [2013-01]
D21F 9/02
.
of the Fourdrinier type [2013-01]
D21F 9/04
.
of the cylinder type [2013-01]
D21F 9/043
. .
{with immersed cylinder} [2013-01]
D21F 9/046
. .
{with non-immersed cylinder} [2013-01]
D21F 11/00
Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines [2013-01]
D21F 11/002
.
{by using a foamed suspension} [2013-01]
D21F 11/004
.
{by modification of the viscosity of the suspension} [2013-01]
D21F 11/006
.
{Making patterned paper} [2013-01]
D21F 11/008
.
{Making apertured paper} [2013-01]
D21F 11/02
.
of the Fourdrinier type [2013-01]
D21F 11/04
. .
paper or board consisting on two or more layers [2013-01]
D21F 11/06
.
of the cylinder type [2013-01]
D21F 11/08
. .
paper or board consisting of two or more layers [2013-01]
D21F 11/10
.
Making imitation mould-made paper [2013-01]
D21F 11/12
.
Making corrugated paper or board [2013-01]
D21F 11/14
.
Making cellulose wadding, filter or blotting paper [2013-01]
D21F 11/145
. .
{including a through-drying process} [2013-01]
D21F 11/16
.
Making paper strips for spinning or twisting [2013-01]
D21F 13/00
Making discontinuous sheets of paper, pulpboard or cardboard, or of wet web, for fibreboard production (making discontinuous sheets of board in moulds D21J; drying paper, pulpboard, or cardboard, in discontinuous sheet form F26B) [2013-01]
D21F 13/02
.
Making hand-made paper [2013-01]
D21F 13/04
.
on cylinder board machines [2013-01]
D21F 13/06
. .
Format rolls [2013-01]
D21F 13/08
. . .
Automatic cut-off rolls [2013-01]
D21F 13/10
.
using board presses [2013-01]
D21F 13/12
. .
Platen presses [2013-01]