Patent ID: 7214039
Filing Date: 2007-05-08
Classification: F04B

Abstract:
1. A pump apparatus which comprises: a plurality of pumps each comprising a displacement pump for pumping a fluid having a reciprocatable piston positioned within a housing having an interior wall spaced apart from said piston, an interior volume of said housing being in fluid communication with a fluid with a fluid inlet to a first check valve and a fluid outlet from a second check valve, said first check valve being in fluid communication with a point of use for said fluid, said second check valve being in fluid communication with a source of said fluid, said first check valve being open and said second check valve being closed when said piston moves toward said first check valve, said first check valve being closed and said second check valve being open when said piston moves away from said first check valve, each said piston of each said displacement pump being movable by a common motor and wherein a fluid pumped from one of said displacement pumps is directed to a seal of at least one of a second displacement pump, said seal positioned to prevent said fluid located within said interior volume from bypassing said piston.