Patent ID: 7946832

Claim:
A dual chamber mixing pump, comprising: a rotating and reciprocating piston disposed in a pump housing, the housing comprising a proximal inlet, a distal inlet, a proximal outlet and a distal outlet, the housing being connected to a proximal seal and a middle seal, the proximal and distal inlets and the proximal and distal outlets being integrally molded with the housing, the proximal and distal outlets being connected, the piston is unitary in structure and comprising a proximal section and a distal end with a pump section disposed between the proximal section and the distal end, the proximal section connected to the pump section at a transition section that extends between the proximal and pump sections, the proximal section is connected to a motor, the proximal section having a first maximum outer diameter, the pump section having a second maximum outer diameter that is greater than the first maximum outer diameter, the transition section having an inner diameter equal to about the first maximum outer diameter of the proximal section and an outer diameter equal to about the second maximum outer diameter of the pump section, the pump section of the piston comprising a proximal recessed section disposed between the transition section and the distal end and a distal recessed section disposed between the proximal recessed section and the distal end, a portion of the pump section of the piston disposed between the proximal and distal recessed sections is at least partially and frictionally received in the middle seal of the housing, the housing and piston defining two pump chambers including a proximal chamber defined by the proximal recessed section, the proximal end of the pump section and the proximal section of the piston and the housing, the proximal chamber in communication with the proximal inlet and the proximal outlet, and a distal chamber defined by the distal recessed section and the distal end of the pump section and the housing, the distal chamber in communication with the proximal inlet and the proximal outlet, the housing further comprising a passageway connected to the first pump chamber that extends around the middle seal and provides communication between the first and second pump chambers.