Dual hydraulic safety valve
US4838355A · kind A · utility
20Cited by
5References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1988 |
| Grant date | Jun 13, 1989 |
| Priority date | — |
| Expiry date | Sep 9, 2008 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B2200/05
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A subsurface well safety valve having two control lines which run from the well surface to first and second piston and cylinder assemblies for controlling the valve. The first of the assemblies is connected to a flow tube for operating the valve but the second assembly is disconnected from the flow tube. When a failure occurs in the primary control system, the first assembly is disconnected from the flow tube and the second piston and cylinder assembly is connected to the flow tube to operate the safety valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.