초록 ▼

In a safety valve having an axially shiftable actuating sleeve operable to move a valve head from a closed to an open position, the actuating movement of the actuating sleeve is normally produced by a small diameter piston mounted on an axially extending spindle secured to the valve housing and coop

In a safety valve having an axially shiftable actuating sleeve operable to move a valve head from a closed to an open position, the actuating movement of the actuating sleeve is normally produced by a small diameter piston mounted on an axially extending spindle secured to the valve housing and cooperating with a primary cylinder which is secured to the actuating sleeve by a shiftable latch. A secondary spindle and cooperating cylinder are provided which are supplied with fluid pressure by an entirely separate line. The secondary cylinder, when moved downwardly by fluid pressure, engages the latch to effect a disconnection of the primary cylinder from the actuating sleeve and concurrently effects the connection of the secondary cylinder to the actuating sleeve. The second cylinder may thus release the primary cylinder from the actuating sleeve in any position of the primary cylinder, including the position corresponding to the fully open position of the valve head. Means are provided on the secondary cylinder for locking the cylinder against return movement when the valve head is shifted to its fully open position.

대표청구항 ▼

The method of operating a downhole well valve by pressurized control fluids supplied from the surface, said downhole valve having a valve actuating member shiftable between a valve closing and valve opening position; a primary fluid pressure actuator operable by a first pressurized control fluid; a

The method of operating a downhole well valve by pressurized control fluids supplied from the surface, said downhole valve having a valve actuating member shiftable between a valve closing and valve opening position; a primary fluid pressure actuator operable by a first pressurized control fluid; a secondary fluid pressure actuator operable by a second pressurized control fluid, the steps comprising: (1) securing said primary fluid pressure actuator to said valve actuating member by a shiftable latch, whereby said valve may be shifted from its closed to its open position by said first pressurized control fluid; and (2) shifting said latch at any position of said primary actuator to concurrently disconnect said primary actuator from said valve actuating member and connect said secondary actuator to said valve actuating member by movement of said secondary actuator produced by said second pressurized control fluid.