D21F
Paper-making machines
Official title: Paper-making machines; methods of producing paper thereon
D21F (Paper-making machines) appears on 7,069 US grants and 4,116 published applications in this corpus.
Search patents in D21F- Granted patents
- 7,069
- Published applications
- 4,116
- Assignees
- 1,289
- Inventors
- 7,163
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 90 | 0 |
| 1977 | 74 | 0 |
| 1978 | 98 | 0 |
| 1979 | 73 | 0 |
| 1980 | 107 | 0 |
| 1981 | 85 | 0 |
| 1982 | 78 | 0 |
| 1983 | 86 | 0 |
| 1984 | 126 | 0 |
| 1985 | 155 | 0 |
| 1986 | 90 | 0 |
| 1987 | 125 | 0 |
| 1988 | 121 | 0 |
| 1989 | 145 | 0 |
| 1990 | 171 | 0 |
| 1991 | 157 | 0 |
| 1992 | 173 | 0 |
| 1993 | 125 | 0 |
| 1994 | 132 | 0 |
| 1995 | 147 | 0 |
| 1996 | 194 | 0 |
| 1997 | 199 | 0 |
| 1998 | 248 | 0 |
| 1999 | 251 | 0 |
| 2000 | 248 | 0 |
| 2001 | 279 | 54 |
| 2002 | 257 | 212 |
| 2003 | 183 | 219 |
| 2004 | 179 | 284 |
| 2005 | 138 | 180 |
| 2006 | 150 | 205 |
| 2007 | 100 | 217 |
| 2008 | 115 | 181 |
| 2009 | 137 | 152 |
| 2010 | 135 | 178 |
| 2011 | 148 | 111 |
| 2012 | 140 | 122 |
| 2013 | 110 | 111 |
| 2014 | 104 | 112 |
| 2015 | 77 | 141 |
| 2016 | 112 | 160 |
| 2017 | 102 | 119 |
| 2018 | 108 | 144 |
| 2019 | 118 | 171 |
| 2020 | 138 | 159 |
| 2021 | 140 | 189 |
| 2022 | 141 | 147 |
| 2023 | 146 | 160 |
| 2024 | 123 | 177 |
| 2025 | 110 | 112 |
| 2026 | 81 | 99 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Main groups
Granted patents with any code in the group
- D21F 1/00Wet end of machines for making continuous webs of paper2,969
- D21F 11/00Processes for making continuous lengths of paper, or of cardboard, or of1,681
- D21F 7/00Paper-making machines: other details of machines for making continuous webs of paper1,343
- D21F 3/00Press section of machines for making continuous webs of paper1,290
- D21F 5/00Dryer section of machines for making continuous webs of paper1,249
- D21F 9/00Complete machines for making continuous webs of paper770
- D21F 2/00Transferring continuous webs from wet ends to press sections115
- D21F 13/00Making discontinuous sheets of paper, pulpboard or cardboard, or of wet web60
Recent patents
- Method for fractionation of highly refined cellulose6 Oct 2026US 12,753,551 B2Stora Enso OYJ
- Web material structuring belt comprising a seam and method for making and using6 Oct 2026US 12,753,552 B2The Procter & Gamble Company
- Adjusting rolls22 Sep 2026US 12,742,289 B2Voith Patent GmbH
- Air and water barrier building panels15 Sep 2026US 12,734,724 B2Gold Bond Building Products, LLC
- Method of controlling the drying of cellulose pulp in a drying step of a pulp production process15 Sep 2026US 12,735,841 B2Andritz Technology and Asset Management GmbH
- Industrial fabric with laser induced structures8 Oct 2026US 2026/0308838 A1AstenJohnson International, Inc.
- Method for applying coating chemicals to yankee dryers for tissue and towel production1 Oct 2026US 2026/0297849 A1Ecolab USA Inc.
- Compostable sleeve apparatus and method of manufacture17 Sep 2026US 2026/0274549 A1
- Method and device for producing a fibrous web17 Sep 2026US 2026/0275634 A1Andritz Kuesters GmbH
- Dewatering apparatus and process17 Sep 2026US 2026/0275635 A1The Procter & Gamble Company
Most cited
By later US patents
- Process for making unitary fibrous structure comprising randomly distributed cellulosic fibers and non-randomly distributed synthetic fibers1,408US 7,067,038 B2The Procter & Gamble Company · 2006
- Method for making a fibrous structure comprising cellulosic and synthetic fibers1,393US 7,354,502 B2The Procter & Gamble Company · 2008
- Tissue paper642US 4,529,480 AThe Procter & Gamble Company · 1985
- Tissue paper641US 4,637,859 AThe Procter & Gamble Company · 1987
- Process for forming a layered paper web having improved bulk, tactile impression and absorbency and paper thereof629US 3,994,771 AThe Procter & Gamble Company · 1976