F04B 49/18
Control: by changing the effective cross-section of the working surface of the
Official title: by changing the effective cross-section of the working surface of the piston
F04B49/18 (Control: by changing the effective cross-section of the working surface of the) appears on 21 US grants and 14 published applications in this corpus.
Search patents in F04B- Granted patents
- 21
- Published applications
- 14
- Assignees
- 17
- Inventors
- 39
- Latest grant
- 23 Sep 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 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 | 2 | 0 |
| 1986 | 2 | 0 |
| 1987 | 2 | 0 |
| 1988 | 1 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 1 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 1 | 1 |
| 2005 | 0 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 1 |
| 2008 | 1 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 0 |
| 2012 | 0 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 0 | 2 |
| 2016 | 0 | 1 |
| 2017 | 0 | 0 |
| 2018 | 1 | 0 |
| 2019 | 2 | 3 |
| 2020 | 1 | 1 |
| 2021 | 1 | 0 |
| 2022 | 1 | 1 |
| 2023 | 0 | 1 |
| 2024 | 1 | 1 |
| 2025 | 1 | 1 |
| 2026 | 0 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Variable diameter valve bores for thru rod fluid ends23 Sep 2025US 12,421,950 B2Gd Energy Products, LLC
- Piston in piston variable displacement hydraulic device28 May 2024US 11,994,121 B1Tonand Inc.
- Intensity modifiable intensifier pump7 Jun 2022US 11,353,017 B2Halliburton Energy Services.Inc.
- Metering mechanism for a proportioning pump, and associated pump and usage method13 Apr 2021US 10,975,861 B2Dosatron International
- Manual dual-directional inflating device24 Nov 2020US 10,844,849 B2Dongguan Tiger Point, Metal & Plastic Products Co., Ltd.
- Piston in piston variable displacement hydraulic device30 Jul 2026US 2026/0218690 A1
- Variable diameter valve bores for thru rod fluid ends22 May 2025US 2025/0163902 A1Gd Energy Products, LLC
- Piston in piston variable displacement hydraulic device12 Dec 2024US 2024/0410345 A1
- Fracturing pump assembly2 Feb 2023US 2023/0036956 A1
- Fracturing pump assembly7 Jul 2022US 2022/0213890 A1
Most cited
By later US patents
- Air dryer purge control for turbocharged compressors30US 4,714,483 AAllied Corporation · 1987
- Two stage manual air pump24US 4,508,490 AThe United States of America as represented by the Secretary of the Navy · 1985
- Variable reciprocating plunger pump24US 4,568,249 A1986
- Free piston engine pump with energy rate smoothing19US 4,435,133 APneumo Corporation · 1984
- Dual-rigid-hollow-stem actuators in opposite-phase slurry pump drive having variable pumping speed and force19US 4,790,728 A1988