Theory:

A diaphragm pump (also known as a Membrane pump) is mainly  composed of motor, transmission components, flexible diaphragm,  and check valves. It utilizes a flexible diaphragm that reciprocates  back and forth, creating a temporary chamber, which both draws in  and expels fluid through the pump. When the volume of a chamber  of pump is increased, the pressure decreases, and fluid is drawn  into the chamber. When the chamber pressure later increases  from decreased volume, the fluid previously drawn in is forced out.  Finally, the diaphragm moving up once again draws fluid into the  chamber, completing the cycle. 

Features: 

Compact size     Light weight  

High level of midea tightness    Oil-free operation 

No/low Maintenance          High efficiency with long lifetime