How Does a Check Valve Work?
Check valves are responsible for ensuring proper flow within a fluid system. Also known as non-return or one-way valves, check valves are specifically designed to prevent reverse flow within a pipeline. But how does a check valve work?
Check Valve Function and Operation
To really understand the question: how does a check valve work, you must first understand how they’re constructed. Most check valves are made with a body, seat, disc, and cover. Other types of check valves may come with additional parts like a spring, ball, stem, or hinge pin depending on their design.
Check valves are controlled based on a system’s flow velocity. Once the system reaches the cracking pressure or the minimum upstream pressure needed for the valve to operate, the disc will lift and allow the fluid to pass through. If the fluid pressure decreases or if the flow direction starts to reverse, the disc will automatically close the valve to keep fluid from flowing through. This helps to prevent backflow.
Since check valves rely on the pressure and flow velocity of the fluid in the system to operate, they can usually work without any automation or human interaction. With that said, check valves aren’t typically designed with any form of exterior operation mechanisms like a lever or handle.
Check Valve Applications
Now that you understand the basics of; how does a check valve work, we review the common applications. Check valves are commonly used for industrial pumps and fluid systems in the oil and gas industry. Chemical and power plants also use check valves to prevent reverse flow in advanced machinery. On top of that, check valves can be installed in many process systems to keep fluids of different pressures separated.
Check Valve Selection
While all check valves are designed to ensure proper flow direction, they’re not all the same. There are many types of check valves, and each is intended for specific application and service conditions.
The ideal check valve should be made with the material that’s compatible with the type of liquid or gas you’re working with. You should also make sure that you select the appropriate type of check valve (e.g. spring-assisted in-line check valve, silent check valve) for the application.
How Does a Check Valve Work Takeaways
Most importantly, you need to ensure that the check valve you choose is the correct size for the application, not the line size. Selecting a valve that’s sized for the application keeps the disc stable on the internal stop when the valve is open or closed. This helps to keeps the disc from fluttering and extends the valve’s overall service life.
In this article, you learned: How does a Check Valve work? To learn even more about how check valves work and how to select a check valve for a specific application, read our post discussing the basics of a check valve.