F01K 25/00
Plants or engines characterised by use of special working fluids, not otherwise
Official title: Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
F01K25/00 (Plants or engines characterised by use of special working fluids, not otherwise) appears on 1,876 US grants and 2,007 published applications in this corpus.
Search patents in F01K- Granted patents
- 1,876
- Published applications
- 2,007
- Assignees
- 796
- Inventors
- 3,021
- Latest grant
- 22 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 22 | 0 |
| 1977 | 22 | 0 |
| 1978 | 21 | 0 |
| 1979 | 9 | 0 |
| 1980 | 13 | 0 |
| 1981 | 16 | 0 |
| 1982 | 29 | 0 |
| 1983 | 11 | 0 |
| 1984 | 24 | 0 |
| 1985 | 19 | 0 |
| 1986 | 16 | 0 |
| 1987 | 12 | 0 |
| 1988 | 14 | 0 |
| 1989 | 15 | 0 |
| 1990 | 10 | 0 |
| 1991 | 7 | 0 |
| 1992 | 4 | 0 |
| 1993 | 7 | 0 |
| 1994 | 5 | 0 |
| 1995 | 7 | 0 |
| 1996 | 13 | 0 |
| 1997 | 9 | 0 |
| 1998 | 19 | 0 |
| 1999 | 13 | 0 |
| 2000 | 26 | 0 |
| 2001 | 22 | 1 |
| 2002 | 10 | 12 |
| 2003 | 14 | 22 |
| 2004 | 16 | 29 |
| 2005 | 18 | 26 |
| 2006 | 25 | 36 |
| 2007 | 13 | 38 |
| 2008 | 18 | 34 |
| 2009 | 18 | 66 |
| 2010 | 23 | 80 |
| 2011 | 33 | 118 |
| 2012 | 45 | 109 |
| 2013 | 81 | 145 |
| 2014 | 94 | 126 |
| 2015 | 67 | 132 |
| 2016 | 85 | 138 |
| 2017 | 144 | 128 |
| 2018 | 127 | 126 |
| 2019 | 100 | 98 |
| 2020 | 111 | 106 |
| 2021 | 96 | 74 |
| 2022 | 79 | 108 |
| 2023 | 92 | 75 |
| 2024 | 84 | 87 |
| 2025 | 62 | 58 |
| 2026 | 36 | 35 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- F01K 25/08Plants or engines characterised by use of special working fluids, not otherwise1,384
- F01K 25/06Plants or engines characterised by use of special working fluids, not otherwise436
- F01K 25/005The working fluid being steam, created by combustion of hydrogen with oxygen94
- F01K 25/04The fluid being in different phases63
- F01K 25/02The fluid remaining in the liquid phase43
Recent patents
- Heat engine using a liquid-vapor-phase-changing material22 Sep 2026US 12,742,402 B2Lava Energy Ltd
- Two-phase thermal pump15 Sep 2026US 12,735,999 B2Rolls-Royce North American Technologies Inc.
- Sterically hindered hydrofluoroolefins with dipole moment and their blends with sterically hindered-olefins as refrigerants for high temperature heat pumps and working fluid for organic Rankine cycles8 Sep 2026US 12,729,332 B2Carbon Ventures, LLC
- Low-grade waste heat recovery system using stored hydropower8 Sep 2026US 12,729,633 B2
- Energy storage device and method based on carbon dioxide gas-liquid phase change25 Aug 2026US 12,716,659 B2Exa Energy Technology (Shenzhen) Co. Ltd.
- Ambient temperature thermal adapter for supercritical carbon dioxide power cycle8 Oct 2026US 2026/0309058 A1TerraPower, LLC
- Plant and process for energy management1 Oct 2026US 2026/0298112 A1Energy Dome S.P.A.
- Method of generating energy from sequestered supercritical carbon dioxide17 Sep 2026US 2026/0275831 A1Halliburton Energy Services.Inc.
- Geothermal power generation systems with pressure exchangers17 Sep 2026US 2026/0275967 A1Energy Recovery, Inc.
- Power generation system3 Sep 2026US 2026/0258737 A1Twenty20 Energy Systems Pte Ltd
Most cited
By later US patents
- Submersible power generators and method of operating thereof331US 9,651,032 B2General Electric Company · 2017
- Carbon dioxide power cycle257US 4,498,289 A1985
- Power plant using CO.sub.2 as a working fluid175US 4,765,143 ACBI Research Corporation · 1988
- Reduce pollution hydrocarbon combustion gas generator174US 5,709,077 AClean Energy Systems, Inc. · 1998
- Reduced pollution power generation system163US 5,715,673 AClean Energy Systems, Inc. · 1998