www.saVRee.com Diaphragm Pump Explained| pg. 3
Single and Double Acting Pumps
Diaphragm Pump Operation
Compressed air (typically 6-7 bar/87-101psi pressure) is connected to a double
diaphragm pump via hoses or piping. A pneumatic piston (air distributor) delivers
compressed air to the space behind one of the diaphragms whilst air is simultaneously
exhausted from the other; this is made possible because both diaphragms are mounted
on a common shaft i.e. when one moves, so does the other. Exhausted air is usually
discharged through a muffler to make the pump operate quieter and to eliminate a high
pressure jet of air being intermittently discharged from the pump.
If air is being exhausted, the affected diaphragm contracts and obtains a concave shape.
If air is being supplied, the affected diaphragm expands and obtains a convex shape. As
the diaphragm changes shape, a positive pressure (convex shape), or negative
pressure (concave shape) is created within the pumping chamber. Fluid is sucked into,
or discharged from, the pump, due to the pressure differences created within the
pumping chambers. Non-return valves are used to ensure that flow through the pump
only occurs in one direction.