F01K 21/04
Steam engine plants not otherwise provided for: using mixtures of steam and
Official title: using mixtures of steam and gas; Plants generating or heating steam by bringing water or steam into direct contact with hot gas ({F01K25/005, F02B47/02 take precedence; injecting water or steam into a as gas turbine plant F02C3/305}; direct-contact steam generators in general F22B)
F01K21/04 (Steam engine plants not otherwise provided for: using mixtures of steam and) appears on 371 US grants and 235 published applications in this corpus.
Search patents in F01K- Granted patents
- 371
- Published applications
- 235
- Assignees
- 154
- Inventors
- 555
- Latest grant
- 2 Jun 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 2 | 0 |
| 1978 | 5 | 0 |
| 1979 | 1 | 0 |
| 1980 | 1 | 0 |
| 1981 | 5 | 0 |
| 1982 | 1 | 0 |
| 1983 | 6 | 0 |
| 1984 | 1 | 0 |
| 1985 | 9 | 0 |
| 1986 | 4 | 0 |
| 1987 | 5 | 0 |
| 1988 | 10 | 0 |
| 1989 | 6 | 0 |
| 1990 | 6 | 0 |
| 1991 | 4 | 0 |
| 1992 | 4 | 0 |
| 1993 | 9 | 0 |
| 1994 | 7 | 0 |
| 1995 | 8 | 0 |
| 1996 | 10 | 0 |
| 1997 | 12 | 0 |
| 1998 | 8 | 0 |
| 1999 | 15 | 0 |
| 2000 | 10 | 0 |
| 2001 | 23 | 8 |
| 2002 | 22 | 14 |
| 2003 | 17 | 12 |
| 2004 | 8 | 21 |
| 2005 | 12 | 10 |
| 2006 | 9 | 11 |
| 2007 | 6 | 11 |
| 2008 | 8 | 9 |
| 2009 | 3 | 12 |
| 2010 | 5 | 14 |
| 2011 | 4 | 9 |
| 2012 | 8 | 7 |
| 2013 | 5 | 7 |
| 2014 | 9 | 9 |
| 2015 | 7 | 8 |
| 2016 | 11 | 12 |
| 2017 | 8 | 14 |
| 2018 | 7 | 8 |
| 2019 | 6 | 6 |
| 2020 | 7 | 4 |
| 2021 | 5 | 3 |
| 2022 | 5 | 7 |
| 2023 | 5 | 2 |
| 2024 | 8 | 10 |
| 2025 | 8 | 7 |
| 2026 | 3 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Auxiliary boiler system for steam injection cycle engine2 Jun 2026US 12,644,410 B2Rtx Corporation
- Parallel heat recovery in gas power generation10 Feb 2026US 12,546,236 B2Numerical Analysis Inc.
- Steam turbine bypass for increased water heat absorption capacity steam injected turbine engine10 Feb 2026US 12,546,250 B2Rtx Corporation
- Heat-transfer-liquid-operated turbine and compressor9 Dec 2025US 12,494,697 B2Technion Research & Development Foundation Limited
- Modified Rankine cycle without heat rejection, driven by a wet-vapor-region thermocompressor2 Sep 2025US 12,404,784 B2
- Combined cycle power plant with exhaust gas recirculation ejector4 Dec 2025US 2025/0369372 A1General Electric Technology GmbH
- Parallel heat recovery in gas power generation30 Oct 2025US 2025/0334061 A1Numerical Analysis Inc.
- Vapor generation system and apparatus11 Sep 2025US 2025/0283594 A1General Electric Company
- Heat engine3 Jul 2025US 2025/0215813 A1Technion Research & Development Foundation Limited
- Steam injected turbine engine steam generation control12 Jun 2025US 2025/0188866 A1Rtx Corporation
Most cited
By later US patents
- Hydrocarbon combustion power generation system with CO2 sequestration337US 6,389,814 B1Clean Energy Systems, Inc. · 2002
- Hydrocarbon combustion power generation system with CO2 sequestration216US 7,043,920 B2Clean Energy Systems, Inc. · 2006
- Hydrocarbon combustion power generation system with CO2 sequestration209US 6,170,264 B2Clean Energy Systems, Inc. · 2001
- Self-contained energy center for producing mechanical, electrical, and heat energy199US 6,107,693 ASolo Energy Corporation · 2000
- Semi-closed Brayton cycle gas turbine power systems196US 6,910,335 B2Clean Energy Systems, Inc. · 2005