Fluid-moving device with an internal passageway and a clearance seal

摘要

A fluid-moving device is disclosed. The fluid-moving device comprises a housing defining a suction chamber; at least one internal passageway formed inside the housing; a moving member movably disposed within the chamber; and a sealing member circumferentially disposed between the housing and the moving member. The internal passageway has a first end opening to the suction chamber and a second end connecting to an outside surface of the housing. The sealing member has a fluid-tight relationship with the housing. The sealing member and the moving member define a continuous and uniform gap, having a size that allows the fluid to fill the gap but prevents the fluid from flowing through the gap from the first side to the second side of the opening under an operating pressure differential between the first and the second side.