Air Operated Double Diaphragm Directflo®  Pumps are based in an ” inside-out” technology: the fluid is pumped through the center of the pump and the compressed air acts on outside face of the diaphragms.  Samoa offers a wide range of materials to withstand abrasion, temperature and chemical compatibility satisfying the most demanding applications. DF pumps without the air valve module and end of stroke sensors to be controlled with an external device like a PLC for their use in dosing applications. Used with externally self-driven pumps, the sensor sends a signal to a PLC to reverse the air direction. Sensors assure that the diaphragms complete their stroke and they allow to regulate the pump speed. The sensors are available with NPN, PNP or ATEX (NAMUR) connectors.  The end of stroke sensor allows counting the number of cycles of a pump.  Threaded connection replaces the standard stainless steel sintered muffler for connecting a hose for remote air exhaust. 3/8″ connection for DF30, DF50, DF100, DC20, DC30 and DC50 pumps; 3/4″ for DP200 pumps and 1″ for DF250 pumps.  Samoa has replaced the standard brass disc muffler to further reduce the noise produced by compressed air expansion.