Home » What is a Check Valve used for?

Check valves are a devise that allow media such as liquids, gasses, or steam to flow in only one direction. Also known as one way check valves, they can have a checking mechanism that can be shaped like a ball, disc, piston or poppet. Check-All only manufacturers poppet style spring check valves. The following are some examples of different applications of use.

To Protect Equipment from Backflow Damage

Spring-loaded check valves can be mounted in any flow orientation (with proper spring selection). This particular valve design incorporates a spring to assist in closing the check mechanism and does not require gravity or backflow pressure to function.  When system pressure begins to reduce, flow begins to slow, stop, or even reverse, check valves prevent reverse flow. This protects pumps and other equipment from damage caused by backflow.

Spring Check Valves are used in a wide variety of applications for flow control including, line isolation, priming pumps, media injection, maintaining head pressure, and many others. Proper spring selection (spring setting) is very important to assure optimum check valve performance. This will also improve the life expectancy of the check valve.

Low Pressure Relief Valves

Inline spring-loaded check valves can be used in low pressure relief applications. Utilizing either elastomeric, thermoplastic or metal to metal seals, these valves can be custom-built with spring materials ranging from stainless steels to Titanium, Inconel, or many others. Different spring materials will perform differently depending on their unique properties. The key to pressure relief in this case is that the poppet moves away from the valve seat when the force of the upstream pressure exerts a greater force than that of the spring, allowing the media to pass through the outlet port. When sizing check valves for pressure relief applications, it’s important to know the set pressure and the maximum pressure the system can handle.  

Dual Roles as Vacuum Breakers

In general, these type of valves can be used as vacuum breakers. The purpose of a vacuum breaker is to allow air into the piping system for the purpose of preventing the interruption of  the desired flow of liquid. A tank is a common application where a check valve would be installed at the top of the piping to relieve the vacuum when the tank is being pumped down. Another application where check valves can function as vacuum breakers is when there is a dramatic change in piping elevation. Vacuum relief valves can also be installed in vacuum systems in order to pull a specific amount of vacuum. Moreover, there could be some thermal applications where the media can change from very hot temperatures to very cold temperatures, and the differences in volume between temperatures is an instance that may require a vacuum breaker to relieve that vacuum when it is created as a result of a variance in temperature.

Engineering spring check valves since 1958, Check-All® Mfg. Co. is an outstanding source for all your check valve, vacuum breaker, and low pressure relief applications. Use the comments to post your questions or tag us on social media. Stay tuned for our next article!