| 摘要 |
<p>VALVE This application is a division of my copending Canadian application Serial No. 369,588, filed April 1, 1981. A valve and particularly a safety valve for use in controlling flow from a well in which an external motor is utilized to shift the actuator of a valve such as a ball valve. The reciprocating rod of the motor is protected by resilient means between the crosshead attached to the motor and the reciprocating actuator. The actuator is latched when the valve is in the open position so that it cannot be moved to closed position except by movement of the reciprocating motor. The valve and seat assembly are designed to be replaced as a unit and can be fabricated as a subassembly with the valve in exact open alignment when the reciprocating actuator is in full valve open position as determined by a stop against which the valve member bottoms. The valve may have its actuator moved beyond the normal reciprocating range for opening and closing of the valve member to permanently lock the valve member in full open position without hindering further reciprocation of the actuator so that it can be used as a control for a secondary valve. The housing and actuator are provided with latch means and a secondary valve with a secondary actuator are landed in the housing and in the actuator so that reciprocation of the actuator then moves the secondary valve between open and closed positions.</p> |
