Diaphragm vacuum pumps is regularly used in order to pre-charge the suction dampeners that are working in atmospheric pressure condition. 
The principle of operating is considering a flexible diaphragm in the pump head that is moved up and down via a connecting rod, by the action of an eccentric mounted to the motor shaft. On the down-stroke, air is drawn into the pump chamber and expelled on the up-stroke. One-way flapper valves installed within the pump-head controls the direction of air flow.
Diaphragm pumps are oil-free and they are characterized by low noise, high efficiency and minimal current consumption 

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