Failsafe gas closed safety valve
A subsurface well safety valve is described for controlling the fluid flow through a well conduit comprising: a housing having a bore; a valve closure member moving between open and closed positions for controlling the fluid flow through the bore; a flow tube telescopically moving in the housing for controlling the movement of the valve closure member; a piston and cylinder assembly positioned in the housing and one of the piston and cylinder engages the flow tube, a first side of the assembly adapted to be in communication with a fluid control passageway to the well surface; a gas chamber in the housing in communication with the second side of the assembly acting on the assembly in a direction to close the valve; spring means between the housing and the flow tube acting on the flow tube in a direction to close the valve; seal means between the piston and cylinder; and openable and closable equalizing means for equalizing fluid pressure on opposite sides of the piston and cylinder assembly in the event of a failure in the seal means thereby allowing the spring means to close the valve.
- Assignee:
- Camco, Inc., Houston, TX
- Patent Number(s):
- US 4660646
- OSTI ID:
- 6776339
- Resource Relation:
- Patent File Date: Filed date 27 Nov 1985
- Country of Publication:
- United States
- Language:
- English
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