Slow closing check valve consists of main valve, check valve, needle valve, ball valve, micro filter and pressure meter to form a hydraulic control receiver system. Utilizing hydraulic automatic operation, it can make the main valve get opening or closing speed. Preventing the generation of water strike of water clock, in order to achieve slow closing muffling. This product utilizes hydraulic self-control, without other devices and energy, easy maintenance, smooth opening and slow closing. It is mainly used in building, living area and other water supply pipe network system and city water supply project.

Slow-closing check valves prevent water hammer from starting and stopping the pump. When the valve is fed from the inlet end, the water enters the main valve control chamber through the micro filter, needle valve, check valve, and then drains downstream through the ball valve. Because the needle valve opening is smaller than the ball valve opening, that is, the main valve control room drainage rate is greater than the rate of water intake, so the control room pressure is reduced, acting on the main valve disk at the lower end of the inlet pressure to open the main valve to the downstream water supply.

Slow-closing check valve is mainly installed in the more serious impact of water hammer, safety requirements of higher places, such as high-rise building fire protection system pump outlet, should be installed slow-closing check valve. Through the slow-closing check valve closing time adjustment, effectively reduce water hammer and noise. When the pipeline stops supplying water, if the downstream water begins to flow back, part of the return water through the ball valve into the main control room, due to the role of the check valve, the return water can not flow out of the main control room, resulting in the gradual pressurization of the main control room, slowly close the main valve.