Patent ID: 8814133

Claim:
An automatic speed searching device for a partial stroke test of a control valve, the automatic speed device comprising: a spool valve operatively connected to a pilot valve, the pilot valve being configured to position the spool valve to one of an open position and a closed position, the spool valve including a first control fluid inlet, a first control fluid outlet, and a second control fluid outlet, the first control fluid inlet being fluidly connected to a supply of control fluid and the first control fluid outlet being configured to be connected to a valve actuator; a blocker valve fluidly connected to the second control fluid outlet of the spool valve; and an electrical module operatively connected to the pilot valve, the supply of control fluid, and the blocker valve, the electrical module generating pulse control signals, wherein the pilot valve and the blocker valve open or close in steps in response to the control signals, and the open position of the spool valve fluidly connects the first control fluid inlet to the first control fluid outlet and the closed position of the spool valve fluidly connects the first control fluid outlet to the second control fluid outlet.