PRE-COMPRESSION RELIEF PORTING FOR POSITIVE DISPLACEMENT PUMPS

摘要

A positive displacement pump (1) having a pump element having at least one variable volume displacement chamber (2), and a relief passage (7) for relieving pressure from the displacement chamber when the displacement chamber is decreasing in volume and is not in communication with an intake (3) or discharge (4) port. A valve member (34), such as a reed valve, is provided to regulate flow through the relief passage (7).