China Non-Surge Check Valve Manufacturer Shinjo Supplies 300X Non-Surge Check Valve, Cast iron, Ductile iron, WCB. 300X Non-Surge Check Valve closes automatically in case of prevent mediums back-flow. The Non-Surge Check Valve allows flow when inlet pressure in higher than the outlet pressure. The valve has the principal of slow-open, quick-close and slow-close into one to prevent water hammering when the pump starts or closes. Non-Surge Check Valve opens and closes at controlled speed to ensure smooth flow. Used on the pump outlet of a water supply system to prevent mediums back-flow, water hammer and water shock. It has three functions as an electric valve, check valve and water hammer remover. z