POPPET VALVE HAVING EXTERNAL ADJUSTMENT FOR A FLOW RESTRICTOR

摘要

A poppet valve has a flow restrictor downstream of the poppet (49) which is externally adjustable by rotation of the poppet valve stem (52). The restrictor is in the form of a throttle ring (71) threadedly mounted on a valve guide (33) and the throttle ring has a diameter less than that of the valve port (16) sealed by the poppet so that the assembly of the throttle ring is removable through the valve port while inadvertent removable is prevented by projecting cap screws on the throttle ring extending to a diameter greater than that of the valve port. The valve poppet is also provided with a contour area adjacent the seat which provides a restriction after initial opening movement of the poppet to minimize erosive wear on the poppet sealing surfaces when the pressure drop occurs adjacent these surfaces.