The Micro Resistance Slowly-Closing Non Return /check Valve
 

The micro resistance slowly-closing non return valve is also known as micro-resistance slow-closing check valve. Its role is to prevent the medium backflow in the pipeline.It is mainly used in water purification, source water, sewage, seawater and other media supply and drainage pipelines, installed in the pump outlet, to cut off the backflow of the medium to eliminate the automic energy damage of the water hammer, to protect the safe operation of the pipeline and water pump.

Working principle： 
The valve is composed of valve body ,2 pcs valve disc ,spring ,oil storage cylinder ,small piston and needle valve . By the thrust of the inlet medium, the two discs will be smoothly opened.At the same time, the imported pressure medium into the lower part of the piston in the oil storage cylinder, push the piston, the oil of the upper part of the piston through the needle valve respectively into the end of the small cylinder on both sides of the valve body, so that the piston rod in the small cylinder is extended.
When the inlet medium pressure drops less than the outlet pressure, the medium will return and the disc will automatically close under the action of spring and medium return.However, due to the piston rod in the extended position, the disc can not be fully closed against the remaining 20 percent of the area through the medium, so as to play the role of hammer elimination.
The disc is supported by the piston rod, the pressure oil in the rear chamber of the piston enters the storage cylinder slowly through the needle valve, and the disc closes gradually.The disc is divided into fast and then slow two steps to close, to prevent motor reversal and hammer mute happens.