US Patent 6901960 Double diaphragm pump including spool valve air motor

A double diaphragm pump including a pump housing, first and second pump diaphragms, an inlet manifold, an outlet manifold, and an air motor. The air motor includes a spool valve having a valve housing, an insert surrounded by the valve housing, and a spool. The valve housing and the insert cooperate to at least partially define a valve chamber, and the spool is slidably positioned within the valve chamber. The spool includes a seal engaging an inner surface of the insert and delimiting the valve chamber into valve subchambers. Movement of the spool within the valve chamber selectively communicates pressurized fluid to one of the diaphragms to move the associated diaphragm, thereby pumping fluid through the pump.