| 摘要 |
A subsurface solenoid operated well safety valve which is locked in the open position, after being opened by the solenoid, for preventing the valve from closing by various forces overcoming the solenoid. A valve closure member in the bore of a housing moves between open and closed positions and is controlled by a tubular member which is biased in a direction to close the valve. An armature is movable in the housing and a solenoid coil is energized to move the armature. A first releasable lock connects the armature to the tubular member for allowing the movement of the solenoid to open the valve. The first lock is released when the valve is opened. A second releasable lock locks the tubular member to the housing in the open position prior to the release of the first lock means. The de-energization of the coil releases the armature and the second lock to allow the valve to close.
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