F04C 29/021
Control systems for the circulation of the lubricant
Official title: {Control systems for the circulation of the lubricant}
F04C29/021 (Control systems for the circulation of the lubricant) appears on 181 US grants and 179 published applications in this corpus.
Search patents in F04C- Granted patents
- 181
- Published applications
- 179
- Assignees
- 94
- Inventors
- 452
- Latest grant
- 26 May 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 1 | 0 |
| 1978 | 1 | 0 |
| 1979 | 2 | 0 |
| 1980 | 1 | 0 |
| 1981 | 0 | 0 |
| 1982 | 0 | 0 |
| 1983 | 3 | 0 |
| 1984 | 2 | 0 |
| 1985 | 2 | 0 |
| 1986 | 0 | 0 |
| 1987 | 1 | 0 |
| 1988 | 1 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
| 1993 | 1 | 0 |
| 1994 | 2 | 0 |
| 1995 | 0 | 0 |
| 1996 | 1 | 0 |
| 1997 | 3 | 0 |
| 1998 | 1 | 0 |
| 1999 | 2 | 0 |
| 2000 | 1 | 0 |
| 2001 | 5 | 1 |
| 2002 | 2 | 4 |
| 2003 | 4 | 1 |
| 2004 | 1 | 3 |
| 2005 | 2 | 3 |
| 2006 | 1 | 2 |
| 2007 | 1 | 2 |
| 2008 | 1 | 2 |
| 2009 | 1 | 2 |
| 2010 | 1 | 3 |
| 2011 | 0 | 8 |
| 2012 | 2 | 7 |
| 2013 | 8 | 8 |
| 2014 | 7 | 9 |
| 2015 | 4 | 7 |
| 2016 | 9 | 15 |
| 2017 | 12 | 14 |
| 2018 | 8 | 14 |
| 2019 | 8 | 14 |
| 2020 | 17 | 16 |
| 2021 | 12 | 7 |
| 2022 | 12 | 13 |
| 2023 | 12 | 10 |
| 2024 | 15 | 4 |
| 2025 | 7 | 5 |
| 2026 | 3 | 5 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Refrigerant compressor including an oil level sensor arrangement26 May 2026US 12,638,324 B2Danfoss Commercial Compressors
- Compressor and additional oil injection system having same5 May 2026US 12,618,408 B2Atlas Copco (Wuxi) Compressor Co., Ltd.
- Airend having a lubricant flow valve and controller28 Apr 2026US 12,612,914 B2Ingersoll-Rand Industrial U.S., Inc.
- Dry-compression compressor and method for oil separation for a dry-compression compressor4 Nov 2025US 12,460,643 B2Kaeser Kompressoren SE
- Helical compressor with internal bearings14 Oct 2025US 12,442,373 B2
- Operation control method for engine driven compressor and engine driven compressor27 Aug 2026US 2026/0251144 A1Airman Corporation
- Oil distribution system for multiple-compressor systems20 Aug 2026US 2026/0243242 A1
- Gas Compressor20 Aug 2026US 2026/0243258 A1Hitachi Industrial Equipment Systems Co., Ltd.
- Air Compressor30 Jul 2026US 2026/0218705 A1Hitachi Industrial Equipment Systems Co., Ltd.
- Compressor with multiple lubricant sumps2 Jul 2026US 2026/0185526 A1Thermo King Corporation
Most cited
By later US patents
- Oil level control system129US 6,125,642 ASporlan Valve Company · 2000
- Method and apparatus for regulating a compressor lubrication system53US 5,318,151 AIngersoll-Rand Company · 1994
- Oil equalization system for parallel connected compressors46US 4,383,802 ADunham-Bush, Inc. · 1983
- Method for providing lubricant to thrust bearing41US 5,626,470 AIngersoll-Rand Company · 1997
- Refrigeration system on/off cycle36US 4,180,986 ADunham-Bush, Inc. · 1980