JD745X Diaphragm-Type Multi-Function Pump Control Valve The 300X slow closing check valve is an intelligent valve installed at the pump outlets of high-rise building water supply systems and other water supply systems to prevent medium backflow, water hammer and water surges. It combines the functions of a check valve and a water hammer arrester, effectively improving the safety and reliability of the water supply system. It integrates the technical principles of slow opening, quick closing and s