C01B 21/44
Concentration
Official title: Concentration {(C01B21/40 takes precedence)}
C01B21/44 (Concentration) appears on 8 US grants and 2 published applications in this corpus.
Search patents in C01B- Granted patents
- 8
- Published applications
- 2
- Assignees
- 8
- Inventors
- 17
- Latest grant
- 14 Oct 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 0 | 0 |
| 1982 | 0 | 0 |
| 1983 | 0 | 0 |
| 1984 | 1 | 0 |
| 1985 | 0 | 0 |
| 1986 | 1 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 1 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 1 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 0 | 0 |
| 2005 | 1 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 0 |
| 2012 | 0 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 0 | 0 |
| 2016 | 0 | 0 |
| 2017 | 0 | 0 |
| 2018 | 0 | 0 |
| 2019 | 0 | 0 |
| 2020 | 0 | 0 |
| 2021 | 0 | 0 |
| 2022 | 0 | 0 |
| 2023 | 0 | 2 |
| 2024 | 0 | 0 |
| 2025 | 1 | 0 |
By publication year. Applications have been published since 2001.
Recent patents
- Method of cleaning an apparatus used in the concentration of a mineral acid14 Oct 2025US 12,441,614 B2Covestro Deutschland AG
- Method for producing concentrated nitric acid and installation for carrying out a method of this type29 Nov 2005US 6,969,446 B1QVF Engineering GmbH
- Method of nitric acid formation using a catalytic solution4 Sep 2001US 6,284,212 B1
- Processes for concentrating nitric acid30 Oct 1990US 4,966,276 A
- Methods for chemically reducing nitrogen oxides2 Dec 1986US 4,626,417 AUnion Oil Company of California
Most cited
By later US patents
- Methods for chemically reducing nitrogen oxides34US 4,626,417 AUnion Oil Company of California · 1986
- Process for obtaining nitric acid of a concentration higher than the azeotropic concentration by means of the absorption of nitrogen oxides in water or diluted nitric acid6US 4,064,221 A1977
- Method and apparatus for synthesizing anhydrous HNO.sub.36US 4,443,308 AThe United States of America as represented by the United States Department of Energy · 1984
- Method for producing concentrated nitric acid and installation for carrying out a method of this type4US 6,969,446 B1QVF Engineering GmbH · 2005
- Method of nitric acid formation using a catalytic solution2US 6,284,212 B12001