F04D 29/68
By influencing boundary layers
Official title: by influencing boundary layers {(by bleeding elastic fluid F04D27/0215)}
F04D29/68 (By influencing boundary layers) appears on 1,005 US grants and 1,052 published applications in this corpus.
Search patents in F04D- Granted patents
- 1,005
- Published applications
- 1,052
- Assignees
- 382
- Inventors
- 2,032
- Latest grant
- 22 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 2 | 0 |
| 1978 | 5 | 0 |
| 1979 | 5 | 0 |
| 1980 | 4 | 0 |
| 1981 | 0 | 0 |
| 1982 | 2 | 0 |
| 1983 | 2 | 0 |
| 1984 | 3 | 0 |
| 1985 | 2 | 0 |
| 1986 | 4 | 0 |
| 1987 | 5 | 0 |
| 1988 | 3 | 0 |
| 1989 | 6 | 0 |
| 1990 | 3 | 0 |
| 1991 | 5 | 0 |
| 1992 | 5 | 0 |
| 1993 | 8 | 0 |
| 1994 | 9 | 0 |
| 1995 | 11 | 0 |
| 1996 | 6 | 0 |
| 1997 | 5 | 0 |
| 1998 | 5 | 0 |
| 1999 | 10 | 0 |
| 2000 | 10 | 0 |
| 2001 | 13 | 2 |
| 2002 | 14 | 16 |
| 2003 | 19 | 16 |
| 2004 | 11 | 16 |
| 2005 | 15 | 28 |
| 2006 | 13 | 18 |
| 2007 | 13 | 29 |
| 2008 | 10 | 33 |
| 2009 | 15 | 40 |
| 2010 | 14 | 46 |
| 2011 | 19 | 45 |
| 2012 | 52 | 40 |
| 2013 | 32 | 45 |
| 2014 | 29 | 53 |
| 2015 | 37 | 59 |
| 2016 | 30 | 66 |
| 2017 | 56 | 59 |
| 2018 | 55 | 65 |
| 2019 | 74 | 66 |
| 2020 | 69 | 71 |
| 2021 | 68 | 51 |
| 2022 | 74 | 45 |
| 2023 | 45 | 47 |
| 2024 | 48 | 36 |
| 2025 | 42 | 29 |
| 2026 | 15 | 31 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Compressor shroud with swept grooves22 Sep 2026US 12,742,459 B2Pratt & Whitney Canada Corp.
- Flow grid and ambient air purification device4 Aug 2026US 12,697,572 B2MANN+HUMMEL Life Sciences & Environment Holding Singapore Pte. Ltd.
- Centrifugal compressor with liquid injection23 Jun 2026US 12,663,023 B2Daikin Industries, Ltd.
- Fan casing or liner with interchangeable tip treatment segments26 May 2026US 12,638,024 B2Rolls-Royce North American Technologies Inc.
- Compressor cooling system for a turbofan engine19 May 2026US 12,631,125 B1Pratt & Whitney Canada Corp.
- Fan casing or liner with interchangeable tip treatment segments3 Sep 2026US 2026/0258814 A1Rolls-Royce North American Technologies Inc.
- Flow machine and method for producing a flow machine component guiding a flow medium27 Aug 2026US 2026/0251156 A1Ziehl-Abegg SE
- Centrifugal compressor and turbocharger13 Aug 2026US 2026/0235140 A1Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.
- Blower6 Aug 2026US 2026/0226913 A1Carrier Japan Corporation
- Ported shroud centrifugal compressor6 Aug 2026US 2026/0226917 A1Ohio State Innovation Foundation
Most cited
By later US patents
- Roto-dynamic pump with a backflow recirculator149US 4,375,937 AIngersoll-Rand Company · 1983
- Reduction of turbomachinery noise149US 6,004,095 AMassachusetts Institute of Technology · 1999
- Fan shroud with integral air supply124US 5,881,685 ABoard of Trustees operating Michigan State University · 1999
- Fan124US 8,092,166 B2Dyson Technology Limited · 2012
- Cooling fan shroud121US 5,762,034 ABoard of Trustees operating Michigan State University · 1998