D21D 1/303
Double disc mills
Official title: {Double disc mills}
D21D1/303 (Double disc mills) appears on 88 US grants and 72 published applications in this corpus.
Search patents in D21D- Granted patents
- 88
- Published applications
- 72
- Assignees
- 38
- Inventors
- 125
- Latest grant
- 17 Feb 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 2 | 0 |
| 1978 | 2 | 0 |
| 1979 | 1 | 0 |
| 1980 | 0 | 0 |
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 2 | 0 |
| 1984 | 0 | 0 |
| 1985 | 2 | 0 |
| 1986 | 7 | 0 |
| 1987 | 1 | 0 |
| 1988 | 1 | 0 |
| 1989 | 2 | 0 |
| 1990 | 0 | 0 |
| 1991 | 2 | 0 |
| 1992 | 0 | 0 |
| 1993 | 2 | 0 |
| 1994 | 0 | 0 |
| 1995 | 3 | 0 |
| 1996 | 0 | 0 |
| 1997 | 1 | 0 |
| 1998 | 2 | 0 |
| 1999 | 0 | 0 |
| 2000 | 1 | 0 |
| 2001 | 0 | 0 |
| 2002 | 1 | 2 |
| 2003 | 0 | 2 |
| 2004 | 0 | 2 |
| 2005 | 1 | 0 |
| 2006 | 1 | 0 |
| 2007 | 1 | 0 |
| 2008 | 1 | 1 |
| 2009 | 0 | 2 |
| 2010 | 3 | 0 |
| 2011 | 0 | 2 |
| 2012 | 0 | 0 |
| 2013 | 1 | 3 |
| 2014 | 0 | 5 |
| 2015 | 2 | 4 |
| 2016 | 3 | 3 |
| 2017 | 2 | 7 |
| 2018 | 2 | 3 |
| 2019 | 6 | 7 |
| 2020 | 6 | 4 |
| 2021 | 4 | 9 |
| 2022 | 2 | 6 |
| 2023 | 7 | 2 |
| 2024 | 10 | 7 |
| 2025 | 1 | 1 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Apparatus and method for processing wood fibers17 Feb 2026US 12,553,182 B2International Paper Company
- Apparatus for grinding a fibrous material suspension7 Jan 2025US 12,188,177 B2Andritz Inc.
- Accessory for disc refiner13 Aug 2024US 12,060,680 B2Valmet Corporation
- Method for controlling a device for treating high-consistency pulp23 Jul 2024US 12,043,959 B2Voith Patent GmbH
- Double-disc refiner18 Jun 2024US 12,012,695 B2Valmet Corporation
- Apparatus and method for processing wood fibers10 Jul 2025US 2025/0223760 A1International Paper Company
- Blade for a refiner for refining lignocellulosic material, and refiner comprising at least one blade26 Dec 2024US 2024/0426051 A1Valmet Corporation
- Method and apparatus for producing a mouldable cellulosic fibrous material28 Nov 2024US 2024/0392502 A1Papyrus Australia Limited
- Apparatus and method for processing wood fibers31 Oct 2024US 2024/0360622 A1International Paper Company
- Accessory for disc refiner3 Oct 2024US 2024/0328085 A1Valmet Corporation
Most cited
By later US patents
- Three zone multiple intensity refiner44US 5,248,099 AAndritz Sprout-Bauer, Inc. · 1993
- Pulp refiner with fluidizing inlet36US 4,820,381 AInternationa Paper Company · 1989
- Method of high shear comminution of solids27US 9,227,196 B2H R D Corporation · 2016
- Refiner disk22US 4,005,827 ABeloit Corporation · 1977
- Refiner head assembly and refining disk therefor22US 4,036,443 ABeloit Corporation · 1977