Backflow prevention devices
US4190071A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1977 |
| Grant date | Feb 26, 1980 |
| Priority date | — |
| Expiry date | Sep 12, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87917
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A backflow prevention device is disclosed which includes a pressure differential relief valve. The relief valve includes a lift chamber functioning to accelerate opening of the valve to assure that the valve fully opens once it has partially opened. The relief valve also includes construction features which allow control of the opening timing of the valve and which cause added closing force to be applied on the valve member to provide more positive closure thereof. Furthermore, a member is provided which substantially eliminates transfer of torque from a spring in the relief valve to a diaphragm therein and substantially eliminates angular cocking of the moveable valve assembly also in the relief valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.