High-pressure pump valve assembly - has closure member sliding on cylinder with clearance acting as throttle when closed valve is pressurised

摘要

The valve assembly is particularly intended for a high-pressure pump with a piston (2). It comprises an annular seat (13a,b) for a bush-shaped closure member (15a,b) controlling the flow passage (21a,b). The member is slidable on a cylindrical surface (16a,b) and has its seating surface (19a,b) radially outward of the surface (16a,b). The narrow annular gap (18a,b) between the closure member and the surface (16a,b) acts as throttle between high and low pressure when the valve is in the closed position. Without high-pressure load on the closure member, the gap (18a,b) width pref. is a fraction of one mm, e.g. between 0.005 and 0.02 mm, which width may be reduced by the member being subjected to this pressure.