CHECK VALVE

摘要

A valve functioning as a check valve in normal operation, but which provides a reverse flow of fluid should a vacuum or cavitation of fluid occur in a hydraulic line in which the valve is mounted. A passageway through a pilot valve provides communication between an inlet port and one side of a sensing diaphragm disposed in a control chamber, while the chamber on the other side of the diaphragm is referenced to atmosphere. A poppet valve is slidably mounted upon the pilot valve and their assembly with the valve housing produces a volumetric spacing or dimension constituting a portion of a fluid flow path extending between an outlet port to the pilot valve but not to the inlet port in normal operation. Should a vacuum or cavitation occur, the sensing diaphragm actuates the pilot valve to dump the pressure in the flow path portion into the passageway and then to the inlet port while pressure on the poppet valve is relieved. The poppet valve opens to provide a reverse flow of fluid. Should a rupture occur in the hydraulic line, the poppet valve seats to prevent reverse flow of fluid to the rupture.