Slow close check valve working principle

Slow close check valve from the main valve, check valve, needle valve, ball valve, micro shape filter and pressure gauge of hydraulic control of system. Using hydraulic automatic operation, can make the main valve to get the best opening or closing speed. Prevent the formation of zhong water water hammer, in order to achieve slowly-closing silencing effect. When slow close check valve from the inlet water supply, water through the micro filter, needle valve, check valve into the main valve control room, through the ball valve and drainage to the downstream. Because the needle valve opening is less than the ball valve opening, the main valve control room is greater than the water drainage speed, so the control room pressure is reduced, on the main valve inlet pressure of the bottom of open the main valve to supply water to the water downstream. When pipe to stop water supply, if the downstream water flowing back, part of the return water enters the main control room, the ball valve with one-way valve, the reflux water cannot flow from the main control room, cause the main control room pressure rise gradually, slowly closing the main valve.