Fluid flow control valve and actuator for changing fluid flow rate

Abstract

A fluid flow control valve and actuator therefor for changing fluid flow rate. A fluid flow control valve comprises a housing having a bore and an inlet and an outlet which form a flow passage through the housing. The valve also comprises a piston mounted in the bore, a fluid flow orifice communicating with the inlet and the outlet, springs which bias the piston toward the inlet, and a valve seat which is matable with the piston and is slidable within the housing to vary fluid flow rate. An actuator for changing fluid flow rate of the valve is comprised of a housing having a bore, a piston dividing the bore into a first chamber and a second chamber, springs in the second chamber for biasing the piston toward the first chamber, an actuator fluid inlet communicating with the first chamber, and an actuator fluid outlet communicating with the first chamber. The valve seat at least partially projects into the actuator second chamber and the actuator piston is adapted to slide within the bore to contact the valve seat upon application of a predetermined pressure of actuator fluid into the first chamber to slide the valve seat within the valve housing to vary fluid flow rate.