Diaphragm position control system

A method of operating a diaphragm pump, the diaphragm pump comprising:

• a housing having a pumping chamber containing fluid to be pumped, and a transfer chamber adapted to contain hydraulic fluid;
• a diaphragm supported by the housing, the diaphragm defining a pumping chamber side and a transfer chamber side, the pumping chamber side at least partially defining the pumping chamber and the transfer chamber side at least partially defining the transfer chamber;
• a driven plunger sliding in a reciprocating motion and forcing hydraulic fluid against the diaphragm;
• a first valve allowing hydraulic fluid into the transfer chamber;
• a second valve allowing hydraulic fluid to be removed from the transfer chamber;
• a hydraulic fluid reservoir in fluid communication with the transfer chamber;
• the method comprising:
• operating the diaphragm pump at a pumped fluid inlet pressure;
• setting a pressure regulator to controllably allow fluid to flow to the transfer chamber, the pressure regulator being actuated at a hydraulic pressure greater than the fluid inlet pressure of pumped fluid, wherein make-up hydraulic fluid flows to the transfer chamber when the pressure regulator is actuated;
• setting pressures of the pressure regulator and starting the diaphragm pump, followed by starting an oil pump supplying the make-up hydraulic fluid.