Patent ID: 7922468
Filing Date: 2011-04-12
Classification: F04C

Abstract:
1. A gear pump for a working fluid comprising: a pump housing defining a rotor chamber and a pump inlet and a pump outlet; a rotor set in the rotor chamber and rotatable in a pumping direction, the rotor set comprising an inner rotor and an outer rotor, the inner and outer rotors each having teeth that move in and out of meshing engagement as the rotor set rotates forming a series of successive pumping chambers between the rotor teeth, each pumping chamber having a volume that increases as the teeth move out of meshing engagement and decreases as the teeth move into meshing engagement; an outlet port in fluid communication between the pump outlet and the pumping chambers as the volume of the pumping chambers decreases; and an inlet port in fluid communication between the pump inlet and the pumping chambers as the volume of the pumping chambers increases, the inlet port terminating in the pumping direction with a radially inwardly extending ramp portion, the ramp portion operating to close each successive pump chamber at a radially inner portion.