Diaphragm pumps are positive displacement pumps that use a combination of the reciprocating action of rubber and balls. Rubber, thermoplastic or Teflon diaphragm and a suitable diaphragm are used in these pumps. It is made up of two pumping chambers that are filled and discharged alternately by the movement of flexible diaphragms. To generate the pumping action, compressed air is alternately fed into and vented from air chambers on opposite sides of the diaphragms. When the diaphragm of a diaphragm pump moves up, the volume of a chamber of either type of pump pressure increases, the pressure decreases, and fluid is drawn into the chamber. When the chamber pressure later increases from decreased volume, the diaphragm moves down, and the fluid previously drawn in is forced out of the chamber of a diaphragm pump. Finally, the diaphragm moving up once again draws fluid into the chamber, completing the cycle. This action is similar to that of the cylinder in an internal combustion engine.