Patent ID: 7086366

Claim:
A dual pumping element fluid pump system comprising: a primary pump element having an intake port that receives fluid from a fluid supply and a discharge port; a secondary pump element having an intake port that receives fluid from a fluid supply and a discharge port; a fluid flow control valve that is in fluid communication with said primary pump element and said secondary pump element, said flow control valve having a valve member that is movable between a normally open position and a closed position; a recirculation passageway that connects said secondary pump element discharge port with said secondary pump element intake port; a leak back mechanism allowing fluid to flow around or through said valve member to said recirculation circuit when said valve is in said closed or substantially closed position to prevent cavitation or overheating of said secondary pump element; wherein when said system is operating at low speeds, said fluid control valve is in said normally open position and said system is provided with fluid from said primary pump element discharge port and said secondary pump element discharge port; and wherein when said system is operating at high speeds said fluid flow control valve is moved to said closed position directing said fluid from said secondary pump element discharge port through said recirculation passageway to said secondary pump element intake port.