Check valves,non-return valves,are designed to prevent the reversal of flow in a piping system. These valves are activated by the flowing material in the pipeline.The pressure of the fluid passing through the system opens the valve, while any reversal of flow will close the valve.Closure is accomplished by the weight of the check mechanism,by back pressure, by a spring, or by a combination of these means.

 pressure sealed bonnet check valve,swing check valve designed and manufacturered according to ASME B16.34,test and inspect to API598,API6D.

That opening has to be clear in order for anything to pass through. The disc is attached to a hinge, so the disc can swing open or closed when liquid hits the disk. It's kind of like a circular door. The direction of the flow is the most important thing when using these valves.

 As stated before, a swing check valve is for when you want fluid traveling in only one direction. Another important detail about these valves is that they require no external power, which makes them ideal for a wide range of applications. They also let fluid pass through without slowing down the flow much when fully open.Swing check valves are usually installed in conjunction with gate valves because they provide relatively free flow.They are recommended for lines having low velocity flow and should not be used on lines with pulsating flow when the continual flapping or pounding would be destructive to the seating elements.This condition can be partially corrected by using an external lever and weight.