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Smashing The Water Hammer: How To Find The Right Check Valve

by Pamela Hill

Water hammer is an effect that results from high-pressure shock waves that result from fluids that cannot be compressed. The shock waves result from the water suddenly needing to stop within a pipe. This is especially a problem when the water is flying at a high velocity, when there is a large volume of water and when there are elevation changes in the piping. To avoid this problem, you need the right check valve.

The Effects Of Water Hammer

When your piping has a water hammer problem, it is most often that the check valve is to blame. For a check valve to close completely, it requires gravity and a flow reversal. When it shuts and the water collides with the valve, the water hammer results.

In many cases, a water hammer has only a slight and undetectable effect. In other cases, the water hammer produces the characteristic banging noise and can be annoying, but otherwise harmless. However, if the water hammer is severe enough, it can cause the pipe to burst. The pipes can be moved out of place. Also, the pressure wave can damage the impeller and drive of the water pumps.

Finding The Right Check Valve

Fortunately, there are special water check valves that are designed to be more resistant to water hammer. They have a non-slam, spring-assisted design that shuts off very tightly. These check valves are also more rugged and have been tested to handle high water pressure.

Check Valves And Flow

Another aspect of making a check valve resistant to water hammer is to make sure that the check valve is sized for the application it will be used under rather than the line size. The disc will need to be stable against an internal stop either in an open or closed position.

The flow stream determines the performance of the check valve because the check valve is always in the flow stream. Therefore, the check valve may fail when experiencing a flow stream that is of a very high pressure even if the check valve has been sized properly for the line size. This will lead to metal rubbing against metal, which can cause the check valve to fail as a result of the gradual wear.

Also, pressure drop is calculated based on the check valve being completely open. If the check valve is not completely open, the flow rate will be different. Therefore, the right check valve will be tested to perform well under these conditions as well. Testing for each of these conditions can take time, but the benefits of not having to replace piping because of a failed check valve make the process worth the time.

For more information, contact companies like Monumental Supply Company.