What is a Check Valve or Non-return valve (NRV)?
Check valves or non-return valves are self actuated valves and designed to prevent the reversal of flow in a piping system. In other words we can say that Check valves are basically backflow preventers.Valve Check continues to work even if plant loses it power,air supply or hydraulic power source. Even these flow preventers or one way valves do not need operator,s assistance to function.
How Does a Check valve Work?
Check valves are activated by the flowing material in the pipeline.This flowing material may be gas,water ,air ,oil or steam in pipeline. The pressure of the fluid passing through the system opens the check valve, while any reversal of flow will close the valve.Opening of valve is basically lifting or swinging of check valve disc thus allowing the flow in one direction.Closure in check valve, for backflow prevention, is accomplished by the weight of the check mechanism, by back pressure, by a spring, or by a combination of these means.