Valve, actuator and control system therefor

摘要

A hydraulic control system for a valve actuator comprising a first control valve that regulates fluid communication from a fluid pressure source to a first fluid supply tank that is fluidly connected to the valve actuator. A second control valve regulates fluid communication from the fluid pressure source to a second fluid supply tank that is fluidly connected to the valve actuator. A flow control member regulates fluid communication between the first and second fluid supply tanks and an exhaust valve that regulates fluid communication between the first and second fluid supply tanks and an outlet.