Failsafe gas closed safety valve
US4660646A · kind A · utility
47Cited by
10References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 27, 1985 |
| Grant date | Apr 28, 1987 |
| Priority date | — |
| Expiry date | Nov 27, 2005 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B2200/05
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A subsurface well safety valve having a flow tube telescopically movable in a housing for controlling the movement of a valve closure member. A piston and cylinder assembly actuates the flow tube and is in communication with hydraulic control fluid from the well surface on one side and a gas biasing chamber on the second side and includes a spring acting on the flow tube to close the valve. An equalizing system equalizes fluid pressure on opposite sides of the piston and cylinder assembly in the event of a failure in the seal between the piston and cylinder thereby allowing the spring to close the valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.