Actuator control system

A control system for controlling the operation of a valve, comprising:

• a. a double-acting valve actuator having first and second portions for receiving operating fluid and being movable between a first position and a second position in response to fluid in said first and second portions, respectively;
• b. a first fluid line connected to said first portion of said valve actuator for conveying fluid thereto;
• c. a second fluid line connected to said second portion of said valve actuator for conveying fluid thereto;
• d. single conduit means for supplying fluid under pressure to operate said valve actuator and also provide a control signal at a point thereof;
• e. reserve fluid means connected to said single conduit means for accumulating fluid under pressure from said single conduit means;
• f. control valve means having an opening position and a closing position, comprising:
• 1. an inlet port and an outlet port conveying fluid under pressure from said single conduit means to said first fluid line when said control valve means is in the opening position;
• 2. an inlet port and an outlet port conveying fluid under pressure from said reserve fluid means to said second fluid line when said control valve means is in the closing position;
• and
• 3. pressure operator means responsive to the control signal to move said control valve means from the opening position to the closing position;
• g. check valve means in said single conduit means interposed between said control signal point and said reserve fluid means;
• and
• h. said reserve fluid means being of a sufficient fluid capacity to provide for a plurality of successive movements of said actuator means between said first and second positions thereof without the addition of fluid thereto from said single conduit means.