Hydraulic high pressure valve controller using the in-situ pressure difference

A method of controlling a valve in the presence of a pressure differential, comprising the steps of:

• providing a hydraulic valve control system, comprising:
• a primary valve connected to a primary valve actuator, the primary valve actuator configured to receive a first fluid having a first pressure at a port and a second fluid having a second pressure at another port, the difference between said first pressure and said second pressure defining a pressure differential, the primary valve actuator configured to respond to said pressure differential so as to actuate said primary valve;
• at least one secondary valve having fluid communication with said primary valve actuator, the first fluid and the second fluid, said at least one secondary valve configured to respond to a command to place said primary valve in any desired state ranging from a fully open state to a fully closed state by applying said pressure differential to said primary valve actuator so as to actuate said primary valve;
• and
• a pump in fluid communication with said at least one secondary valve, said pump configured to respond to said command to place said primary valve in any desired state ranging from a fully open state to a fully closed state by applying a pump pressure to said primary valve actuator by way of said at least one secondary valve when said pressure differential alone is not sufficient to cause said primary valve to attain said desired state;
• commanding that said primary valve be caused to attain a desired state ranging from a fully open state to a fully closed state;
• and
• as necessary, causing said pump to apply a pump pressure to said primary valve actuator when said pressure differential is not sufficient to cause said valve to attain the desired state.