Patent ID: 6203291
Filing Date: 2001-03-20
Classification: F04B,Y10T

Abstract:
A displacement pump comprising:a pump housing with a pumping chamber having a variable volume for providing pumping action, said pumping chamber having an inlet and an outlet for a fluid to be pumped wherein a flow passage from the inlet to the outlet is substantially open during the pumping cycle;a flow control arrangement for controlling the direction of flow through the pump, said flow arrangement comprising in at least one of said inlet and said outlet a flow controlling means;said flow controlling means having one diffuser inlet portion and one diffuser portion as seen in a direction of flow through the pump, said flow controlling means includes a rounded shape at an inlet region forming a smooth transition from a surrounding wall;said diffuser inlet portion having walls admitting a converging flow creating a pressure drop from a pressure maximum at an entrance of the flow controlling means, to an entrance of the diffuser portion;said diffuser portion having diverging walls causing a substantially diverging flow and a pressure increase; andsaid flow controlling means being adapted, for a given flow, to effect a smaller pressure drop in the direction of flow through the pump than in an opposite direction of flow.