IPC Subclass
D21F PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
Introduced: September 1968
Classification Context
- Section:
- TEXTILES; PAPER
- Class:
- PAPER-MAKING; PRODUCTION OF CELLULOSE
- Subclass:
- PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
Description
D21F covers machines and methods for manufacturing paper from cellulose pulp, encompassing the complete papermaking process from pulp preparation through final product formation. This includes wet-end machinery (forming sections, pressing units, dryers), size presses, coating and calendering equipment, and associated control systems. The classification addresses both the mechanical equipment and operational methods for producing various paper grades and qualities on industrial paper machines.
Related Keywords
making of CARDBOARD on paper-making machinesmaking of FIBREBOARD on paper-making machinesFOURDRINIER paper-making machinesmaking SHEET(S) of paper or boardsmaking WATER marks in papermachines for making continuous WEB(S) of paper or board
8 direct subcodes
Child Classifications
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- D21F 1/00 Wet end of machines for making continuous webs of paper
- D21F 11/00 Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibreboard production, on paper-making machines
- D21F 13/00 Methods or apparatus for making discontinuous sheets of paper, pulpboard, or cardboard, or of wet web, for fibreboard production
- D21F 2/00 Transferring continuous webs from wet ends to press sections
- D21F 3/00 Press section of machines for making continuous webs of paper
- D21F 5/00 Dryer section of machines for making continuous webs of paper
- D21F 7/00 Other details of machines for making continuous webs of paper
- D21F 9/00 Complete machines for making continuous webs of paper
Top Applicants
Top 10 applicants by patent filingsfor class D21, 2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,809
- STORA ENSO FI 1,467
- KEMIRA FI 1,086
- KIMBERLY-CLARK CORPORATION US 935
- VALMET TECHNOLOGIES FI 924
- VALMET SE 904
- P&G (PROCTER & GAMBLE COMPANY) US 862
- OJI HOLDINGS CORPORATION 696
- OMYA INTERNATIONAL CH 584
- SOUTH CHINA UNIVERSITY OF TECHNOLOGY 571