Is Your Check Valve Oversized for Your Application?
In a recent blog post, we discussed some of the common check valve problems, and the fact that many of them are not related to the valve itself, but with the selection and/or application of the valve.
One of these problems is oversizing that can lead to a host of problems. Such issues include excess pressure that will wear out the valve and lead to extensive maintenance costs or early replacement needs. This is because the flutter, caused by vibration and/or instability, will rapidly damage the valve.
The Cause of Valve Oversizing
Often, people will size a check valve based on the pipe diameter, which is what leads to oversizing. Not only does this create performance issues, but it means you’re overpaying for a valve much larger than you need. Initial costs and ongoing maintenance costs increase as a result.
Therefore, the rule of thumb is: size your check valve for the application. This will ensure that no fluttering of the disc occurs, and will provide the longest valve lifespan. When a check valve is sized the way an on/off valve is sized, it ignores the fact that the flow conditions of a check valve determine its internal performance.
Application Factors in Check Valve Sizing
The application factors that will typically help determine sizing include flow rates during operating conditions (i.e. constant versus fluctuating, low versus high, etc.), fluid density, and startup conditions. If a check valve is needed for an application requiring a range of flow conditions, it’s known as a high turndown application, and this will require a different size than constant flow rates.
A good check valve manufacturer can help guide you to the right size based on your application; likewise, one who is less experienced might make the mistake of sizing to match the pipe. The right expert knows all of the factors involved in sizing parameters, and will ensure your check valve is not oversized.
If you have questions about check valve sizing and selection, feel free to contact DFT and ask to learn more about our check valve selection and proper sizing for your application.
You can also download our eBook on Check Valve Sizing from the link below: