E21F 7/00
Methods or devices for drawing- off gases with or without subsequent use
Official title: Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
E21F7/00 (Methods or devices for drawing- off gases with or without subsequent use) appears on 123 US grants and 96 published applications in this corpus.
Search patents in E21F- Granted patents
- 123
- Published applications
- 96
- Assignees
- 74
- Inventors
- 301
- Latest grant
- 22 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 1 | 0 |
| 1978 | 4 | 0 |
| 1979 | 2 | 0 |
| 1980 | 1 | 0 |
| 1981 | 9 | 0 |
| 1982 | 2 | 0 |
| 1983 | 2 | 0 |
| 1984 | 3 | 0 |
| 1985 | 1 | 0 |
| 1986 | 3 | 0 |
| 1987 | 2 | 0 |
| 1988 | 0 | 0 |
| 1989 | 1 | 0 |
| 1990 | 1 | 0 |
| 1991 | 1 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 1 | 0 |
| 1999 | 1 | 0 |
| 2000 | 1 | 0 |
| 2001 | 1 | 2 |
| 2002 | 4 | 7 |
| 2003 | 4 | 2 |
| 2004 | 3 | 6 |
| 2005 | 5 | 1 |
| 2006 | 1 | 2 |
| 2007 | 2 | 0 |
| 2008 | 0 | 10 |
| 2009 | 0 | 0 |
| 2010 | 0 | 1 |
| 2011 | 2 | 4 |
| 2012 | 4 | 2 |
| 2013 | 9 | 2 |
| 2014 | 1 | 6 |
| 2015 | 2 | 1 |
| 2016 | 1 | 3 |
| 2017 | 4 | 8 |
| 2018 | 7 | 5 |
| 2019 | 5 | 6 |
| 2020 | 7 | 7 |
| 2021 | 5 | 3 |
| 2022 | 2 | 4 |
| 2023 | 1 | 4 |
| 2024 | 6 | 2 |
| 2025 | 6 | 5 |
| 2026 | 2 | 3 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Method for coal seam gas seepage displacement, seepage water locking and dust reduction22 Sep 2026US 12,742,389 B2Hunan University of Science and Technology
- Permeability enhancement device for coal-seam gas drainage30 Jun 2026US 12,669,055 B2Henan Polytechnic University
- System and method for sealing and pressurizing enclosed facilities via prefabricated modules, plugs, doors, and inserts28 Oct 2025US 12,455,092 B2
- Separator for a fluid stream and method therein30 Sep 2025US 12,427,442 B2
- Coal and gas outburst monitoring device25 Mar 2025US 12,258,865 B2Henan Polytechnic University
- Gas extraction method and system based on non-solidifying sealing material1 Oct 2026US 2026/0298089 A1Taiyuan University of Technology
- Managing methane leaks with minimal impact on productivity25 Jun 2026US 2026/0176969 A1International Business Machines Corporation
- Method for coal seam gas seepage displacement, seepage water locking and dust reduction23 Apr 2026US 2026/0110250 A1Hunan University of Science and Technology
- Systems and methods for production of low carbon intensity hydrogen from geologic sources27 Nov 2025US 2025/0361144 A1Koloma, Inc.
- Permeability enhancement device for coal-seam gas drainage20 Nov 2025US 2025/0354492 A1Henan Polytechnic University
Most cited
By later US patents
- Upgrading and mining of coal308US 6,969,123 B2Shell Oil Company · 2005
- Process for recovering methane gas from subterranean coalseams143US 4,651,836 AMethane Drainage Ventures · 1987
- Method for removing methane from coal120US 4,043,395 AContinental Oil Company · 1977
- Method for production of gas from a coal seam using intersecting well bores100US 6,280,000 B12001
- Method for removal of methane from coalbeds88US 3,934,649 AThe United States of America as represented by the United States Energy Research and Development Administration · 1976