H01F 27/321
Using a fluid for insulating purposes only
Official title: {using a fluid for insulating purposes only}
H01F27/321 (Using a fluid for insulating purposes only) appears on 97 US grants and 89 published applications in this corpus.
Search patents in H01F- Granted patents
- 97
- Published applications
- 89
- Assignees
- 65
- Inventors
- 266
- Latest grant
- 15 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 3 | 0 |
| 1978 | 4 | 0 |
| 1979 | 2 | 0 |
| 1980 | 3 | 0 |
| 1981 | 2 | 0 |
| 1982 | 1 | 0 |
| 1983 | 0 | 0 |
| 1984 | 3 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 1 | 0 |
| 2000 | 2 | 0 |
| 2001 | 3 | 0 |
| 2002 | 2 | 3 |
| 2003 | 5 | 1 |
| 2004 | 0 | 2 |
| 2005 | 1 | 2 |
| 2006 | 2 | 2 |
| 2007 | 0 | 4 |
| 2008 | 1 | 1 |
| 2009 | 0 | 1 |
| 2010 | 4 | 2 |
| 2011 | 3 | 3 |
| 2012 | 2 | 4 |
| 2013 | 3 | 1 |
| 2014 | 2 | 1 |
| 2015 | 1 | 2 |
| 2016 | 3 | 2 |
| 2017 | 0 | 6 |
| 2018 | 1 | 3 |
| 2019 | 8 | 9 |
| 2020 | 5 | 3 |
| 2021 | 4 | 6 |
| 2022 | 1 | 5 |
| 2023 | 5 | 12 |
| 2024 | 6 | 6 |
| 2025 | 2 | 5 |
| 2026 | 8 | 3 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- HV apparatus and a method of manufacturing such apparatus15 Sep 2026US 12,738,415 B2Hitachi Energy Ltd
- Transformer arrangement4 Aug 2026US 12,700,536 B2Hitachi Energy Ltd
- Transformer arrangement12 May 2026US 12,626,857 B2Hitachi Energy Ltd
- Dry high voltage instrument transformer7 Apr 2026US 12,597,557 B2ABB Schweiz AG
- Method and system for breather health assessment for a transformer breather10 Mar 2026US 12,571,671 B2Hitachi Energy Ltd
- Electrical apparatus comprising at least one gelled material24 Sep 2026US 2026/0290681 A1Arkema France
- Transformer apparatus2 Apr 2026US 2026/0094758 A1Eaton Intelligent Power Limited
- Transformer arrangement12 Feb 2026US 2026/0045406 A1Hitachi Energy Ltd
- Coated active component in a high-voltage device and method for increasing the di-electric strength23 Oct 2025US 2025/0327841 A1HSP Hochspannungsgeräte GmbH
- Transformer oil-level monitoring and early warning system11 Sep 2025US 2025/0283749 A1Fortune Electric Co., Ltd.
Most cited
By later US patents
- Food grade vegetable oil based dielectric fluid and methods of using same42US 6,398,986 B1Cooper Industries, Inc. · 2002
- Method of use and electrical equipment utilizing insulating oil consisting of a saturated hydrocarbon oil38US 4,082,866 ARTE Corporation · 1978
- Vegetable oil based dielectric coolant37US 6,037,537 ACooper Industries, Inc. · 2000
- Vegetable oil based dielectric fluid and methods of using same37US 7,651,641 B2Cooper Industries, Inc. · 2010
- Microbial oils with lowered pour points, dielectric fluids produced therefrom, and related methods34US 9,066,527 B2Solazyme, Inc. · 2015