How Do I Select A High Quality Check Valve?

 Did you know that unlike other types of valves, check valves will continue to work if a plant loses power, air, manpower, or all of the above? They are available in a wide variety of sizes, materials and end connections for countless applications.

 

Consideration

Problems with check valves are usually not related to the valve itself, but to the application and other factors. Therefore, as you solve problems or replace check valves, keep the following common problems in mind.

 

Water Hammer

Water hammer is one of the most common check valve problems. Water hammer is a pressure fluctuation caused when a liquid or gas is forced to stop or change direction suddenly, usually occurring when a valve at the end of a piping system suddenly closes. This can cause noise and vibration, which in turn can lead to damage and additional maintenance or repair costs.
However, water hammer can be prevented by using a faster closing check valve that stops the pressure fluctuations and shock waves that can damage and destroy equipment.

 

Backflow

Backflow is another common check valve problem that can be very costly, especially when it occurs at the discharge of the pump and can cause the pump to spin backwards.
A quick closing and tight shutoff valve is necessary to prevent this problem, and the right spring-assisted in-line check valve can do just that, eliminating backflow.

 

Ductile iron Rubber Disc Check Valve

 

Options

Another solution for closing check valves is to look at the type of check valve used in the application. Silent, ball and resilient hinges are alternatives to traditional swing check valves. They each have different characteristics with varying degrees of pressure drop and closing speed.

 

Silent Check Valves

Silent or spring-assisted check valves do not rely on gravity or backflow to close. Instead, the spring closes in about a tenth of a second, before the backflow has a chance to slam the valve shut. It is able to close quickly because it has a shorter stroke than the flap on a conventional check valve.

Ball Check Valves

Ball check valves are economical and very simple valves. They sometimes use a rubber-coated ball that floats and moves away as the flow passes through the valve, and falls into place when the flow stops. This particular valve closes slowly, so the potential for impingement is high.

 

Ductile iron mechanical couplings

 

Conclusion

Each of these valves has different characteristics, features and benefits, and they should be carefully selected for proper installation into the system. If you are having problems with a check valve or need to select a new one for your process, consult an engineer experienced in the selection/sizing of these valves. Doing so will help your system operate at maximum efficiency with fewer impacts and reduced maintenance requirements.

 

KEHUA has 20 years of experience in casting and processing, a full set of laboratory and testing equipment, and more than 20 CNC processing equipment. The company mainly produces gray iron, ductile iron, cast steel, cast aluminum and other products. It can open and produce molds according to drawings or samples provided by customers.

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