Abstract: An apparatus is described wherein for a device for controlling the flow of fluid. A housing having an inlet for receiving the fluid, an outlet for discharging the fluid, and a bore connecting the inlet to the outlet is provided. A piston is disposed in the bore and has a through bore for permitting the flow of the fluid through the piston. A valve member is disposed in the bore of the piston and adapted to engage an internal surface of the piston to block fluid flow through the piston and therefore through the housing, the piston responding to an increase in pressure at the outlet as a result of the fluid flow for moving in a direction toward the valve member until the valve member engages the piston surface to restrict fluid flow. A stop member is disposed in the housing and extends into the bore of the piston for stopping movement of the piston after it engages the valve member.