| 摘要 |
Wellhead flow control valve including a valve body, a hydraulic linear actuator means connected to valve body in alignment with operating chamber. Actuator has Belleville spring return. A seat sleeve carrying a valve seat and an internal lining mounts at outlet of operating chamber. Drive shaft moves flow control member of prescribed configuration into and out of valve seat sleeve. Flow control member and valve seat cause complete flow closure. Hydraulic conduit connects into actuator to admit hydraulic fluid to move piston and to compress spring. Activator is responsive to a pilot signal for: activating a pump control switch; to permit operation of pumps; activating a by-pass valve switch to keep closed a by-pass valve between conduit and sump of pump; and activating a blocking valve switch to keep open a blocking valve connected between pump and actuator. Flow throttling valve connected into conduit between actuator and other valve control apparatus to adjustably control rate of travel of piston by adjusting flow rate. Pressure sensing means connects into product pipe downstream from control valve and connected: to switch by-pass valve switch to open hydraulic by-pass valve and to switch pump control switch to closed position to stop pump and to close control valve when prescribed to high product pressure occurs; and to switch pump control switch to start pump and to switch by-pass valve to close hydraulic pass valve to stop and to open control valve when a prescribed lower product pressure occurs.
|
