Double diaphragm pump having two-stage air valve actuator

Claim 1

A double-diaphragm pumping apparatus having a pair of axially aligned interconnected diaphragms respectively reciprocable within a diaphragm chamber, the chamber having a liquid pumping section and an air section, comprising: a) an actuator chamber located intermediate the respective diaphragm chambers, and a pair of slidable pins, each pin extending between the actuator chamber and one of the air sections of a diaphragm chamber and being slidable by contact from the diaphragm; b) a pilot valve connected to said pair of slidable pins in said actuator chamber; c) an actuator valve in said actuator chamber, said actuator valve having a pair of slidable piston actuating members, and having heat exchanger vanes affixed thereto; d) a pair of first air passages coupled between said pilot valve and respective ones of said pair of slidable piston actuating members; e) a pair of second air passages coupled between said actuator valve and respective ones of said diaphragm chamber air sections; f) means for introducing pressurized air into said actuator chamber, each of said second air passages being selectively and alternately openable to said actuator chamber by movement of said actuator valve; g) an air exhaust chamber in said pumping apparatus, and a third passage connected between said pilot valve and said air exhaust chamber, and a fourth passage connected between said actuator valve and said air exhaust chamber; whereby predetermined positions of said diaphragms causes actuation of said pilot valve, which causes actuation of said actuator valve to direct pressurized air to a corresponding one of said diaphragm chamber air sections, and to exhaust air from the other one of said diaphragm chamber air sections.