Mechanical Diaphragm metering pumps have a diaphragm, two valves, a displacement chamber and a drive mechanism. The diaphragm is a flexible diaphragm that vibrates to create suction to move fluid into and out of the pump chamber. It is located between the side of the discharge chamber and the connection flange. The two valves are usually baffle valves or spring-loaded ball valves made of the selected material by chemical compatibility chart. They operate by allowing fluid to move in and out of the chamber.