Look inside and understand the design
This transparent 3D rendered animation allows one to look inside a membrane pump in operation and see the membrane filters piston in motion and displays how the fluids are pumped in and out of the chamber.
Rotary motion is converted by the piston into positive and negative pressure of the flexible membrane surface inside the pump. The green valves constrain the flow direction of the supply and delivery tubes. The supply valve opens as the membrance chamber volume expands, and the delivery tube opens as the chamber contracts, so the membrane chamber fills and expels a precisely measured volume of liquid with each revolution.