Abstract: A method and apparatus for the diversion of fluid flow at reduced pressure out of a high pressure fluid delivery system when the discharge of the system is closed. A bypass valve having a movable piston oriented transverse to the flow direction and a slidable seal oriented parallel to the flow direction is located between the system pump and discharge. The movable piston has two working surfaces of different areas which define planes parallel to the flow direction so that the working surfaces and therewith the piston are generally responsive only to static fluid pressure. The slidable seal is responsive to dynamic fluid pressure so that when the discharge is closed and the dynamic fluid pressure thereby reduced, the seal moves to interrupt fluid communication between the two working surfaces of the piston.

Abstract: A fluid valve assembly suitable for a number of different uses, including use as a fluid pressure regulator for a pump whose output pressure is to be kept uniform for changing load conditions. The assembly includes a housing, a pair of relatively shiftable valve members in the housing, and means biasing the valve members together. Each valve member has a face which is contiguous to the corresponding face of the other members. One of the valve members has a central orifice therethrough and its face surrounds the orifice to present a land having a length from the orifice to the outer periphery of its corresponding face greater than the diameter of the orifice. The face of a first of the valve members is preferably tapered to present a transversely wedge-shaped space between said faces to facilitate separation of the valve member to open the valve formed thereby. The housing has a fluid inlet in communication with the region surrounding the valve members and a fluid outlet communicating with said orifice.