A Mechanical Diaphragm pump is also a type of positive displacement pump. In this pump the diaphragm becomes the displacement measuring element, as it moves back and forth in the fluid chamber.

Working Principle

The working principle of a Mechanical diaphragm pump is much simplified as compared to the Hydraulically operated diaphragm pump. The power side of the pump and the capacity control are similar to that of other types of reciprocating pumps. However in place of a plunger, the mechanical diaphragm pump uses a spring return mechanism. This mechanism in turn makes the diaphragm to reciprocate which helps in the suction and discharge of the chemical.
Mechanical diaphragm pumps are normally used in water and waste water treatment plants. These pumps are designed for low pressure but high discharge applications.