Neptune dampeners are installed on the discharge side of positive displacement pumps to remove the pulsating flow caused by the start and stop action of the pump. Dampeners ensure a smooth and continuous flow, eliminate pipe vibration and protect in-line instrumentation. Dampeners may also be installed at the pump inlet as an inlet stabilizer to improve the NPSH condition of the pump by reducing the acceleration pressure losses due to the opening and closing of the inlet ball valve.
A pressure chamber is divided by an elastomeric bladder. The lower portion of the chamber is filled with the pumped liquid, the upper portion of the chamber contains an air cushion. The air cushion is pre-charged to a pressure appropriate for the operating condition. The energy from each pump discharge stroke displaces the bladder into the air cushion allowing the dampener to absorb the energy. The air cushion and bladder force liquid out of the bladder during the pump suction stroke.