CPC Main Group
D21F 1/00 Wet end of machines for making continuous webs of paper
Filing statistics
CPC D21F 1/00 belongs to the parent subclass D21F, which recorded 14,174 patent applications worldwide between 2013 and 2023. Annual filings grew from 937 in 2013 to 950 in 2023 (+1%), peaking at 1,654 applications in 2017. The most active applicants in class D21 are VOITH PATENT (1,857 applications), STORA ENSO (1,552 applications) and KEMIRA (1,173 applications).
Source: EPO PATSTAT, worldwide filings
24 direct subcodes
Child Classifications
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- D21F 1/02 Head boxes of Fourdrinier machines
- D21F 1/04 Head boxes of cylinder machines
- D21F 1/06 Regulating pulp flow
- D21F 1/08 Regulating consistency
- D21F 1/10 Wire-cloths
- D21F 1/18 Shaking apparatus for wire-cloths and associated parts
- D21F 1/24 Tilting, raising, or lowering mechanisms for wire-cloths
- D21F 1/30 Protecting wire-cloths from mechanical damage
- D21F 1/32 Washing wire-cloths or felts
- D21F 1/34 Construction or arrangement of spraying pipes
- D21F 1/36 Guiding mechanisms
- D21F 1/44 Watermarking devices
- D21F 1/48 Suction apparatus (suction rolls D21F3/10)
- D21F 1/54 Skimming devices, e.g. froth ledges
- D21F 1/56 Deckle frame arrangements
- D21F 1/58 Deckle straps
Top Applicants
Top 10 applicants by patent filingsfor class D21, 2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,857
- STORA ENSO FI 1,552
- KEMIRA FI 1,173
- KIMBERLY-CLARK CORPORATION US 1,107
- VALMET TECHNOLOGIES FI 965
- VALMET SE 943
- P&G (PROCTER & GAMBLE COMPANY) US 941
- OMYA INTERNATIONAL CH 821
- UPM-KYMMENE CORPORATION FI 512
- SEIKO EPSON CORPORATION JP 501