Pilot control valve utilizing multiple offset slide valves

摘要

A pilot control valve for controlling a reciprocating pump has a valve member shiftable within a valve body between a first or "downstroke" position and a second or "upstroke" position. In its first and second positions, the valve member positions slide valves to allow communication of control fluid to move the piston to a second and first position, respectively. When the piston reaches its second position a poppet disposed in a rod attached to the piston allows control fluid acting on the valve member to depressurize. Pressurized control fluid then acts on the valve member to move to its second position. When the piston returns to its first position, the poppet allows pressurized control fluid acting on the upper surface of the piston to act on the valve member to move the valve member back to its first position and repeat the process.