Patent ID: 9664300
Date: 2017-05-30
CPC Classifications: F16K,Y10T

Claim:
1. A fluid flow control valve including: a valve body having an inlet port, an outlet port in selective fluid communication with the inlet port by a main passageway through the valve body, and a valve seat surrounding the main passageway; a valve member mounted in the valve body for axial movement between closed and open positions respectively blocking and permitting flow through the valve seat, the valve member having a piston portion that separates a control chamber upstream of the valve seat from a point downstream of the valve seat and a pilot orifice through the piston portion for bleeding off pressure from the control chamber to the point downstream of the valve seat; a plunger movable between a first position blocking flow through the pilot orifice and a second position allowing flow through the pilot orifice; axially spaced apart spring energized wiper seals that radially support the piston within the passageway while allowing limited radial movement within the passageway; and a bleed orifice in communication with the inlet port and the control chamber for allowing pressure from the inlet port to build up in the control chamber for urging the valve member toward the first position when the plunger is in the first position, wherein the piston is made of a plastic material, and wherein the bleed and pilot orifices are machined into a steel inserts secured in the plastic material of the piston, and the inserts have on a radially outer surface thereof annular interference ribs that engage in an inner diameter surface of a respective bore in the piston to effect a positive seal and hold within the plastic material of the piston.