The non-return valve is designed for use in Seawater Reverse Osmosis (SWRO) membranesystems. In case the high-pressure pump stops momentarily, the volume of water in themembrane vessel may work as an accumulator and will send flow backwards. In case pumps are placed in parallel, the non-return valve also prevents water from one pump runs into the parallel-coupled pumps at start-up.The function of the valve is prepared for easy installation on the high-pressure outlet.Typically used in connection with APP 53 - 92 pumps.