Category Archive: Check Valves
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
DFT’s ALC and WLC Wafer Check Valves
Water hammer and reverse flow can be ongoing issues for large buildings and industrial piping. In the majority of cases, an unreliable double door or butterfly check valve was utilized and the results are these damaging issues. Double door or butterfly check valves often times incur failure of the door spring or hinge pin; leakage from misaligned doors and seats; reverse flow; and even internal parts flowing down stream.
The harming effects of water hammer include loud noise and rapid vibration to pipe collapse. Reverse flow can damage pumps and motors, a costly proposition to any company.
DFT Inc.’s Pulp and Paper Check Valves: Write On!
If you think of paper manufacturing (and its raw material, wood pulp), you probably think of trees, huge mills, and giant rollers. Water and liquid chemical delivery systems might not be the first things that come to mind. Both, however, comprise important steps in both pulp and paper production. Quick explanation: wood pulp is made up of certain fibers from wood, separated out from the main piece. This separation can be achieved through a number of different methods, one of which is through chemicals specially intended to break down the raw wood, while leaving the key cellulose fiber intact. As you might imagine, these chemicals can be fairly harsh, which is why DFT Inc.’s severe service check valves are the perfect replacement for standard swing check valves on batch digester systems.
The Check Valve Doctor™
DFT in-line check valves began over 60 years ago with a customer’s need for a small metal-seated check valve that could be installed in any position while providing tight shutoff. The Basic- Check® valve was developed to satisfy that need. Over the following decades, other customers’ needs led to the development of the ALC®, DLC®, DSV®, Excalibur®, GLC®, PDC®, SCV® and WLC® styles of axial flow, non-slam silent check valves. Each of these DFT check valves addresses the particular needs of a modern day customer.
DFT’s objective is to diagnose check valve problems, provide solutions and prevent failures. DFT has learned by listening to customers like you that each industry has special needs that can exceed other check valve designs. We specialize in providing in-line check valves that meet customer requirements as opposed to simply meeting line size. In some cases, minor modifications to our valves have solved customer problems while improving performance and extending service life.
The Check Valve Doctor™ continues to grow from satisfying these needs and solving problems, supported by quick response manufacturing and relentless quality control. That’s why DFT non-slam check valves are known around the world as the valve to use to prevent or eliminate water hammer problems. Whatever your size, pressure or piping configurations, DFT has a check valve for you. Thank you for considering DFT for your check valve requirements.
Click here to view our Check Valve Catalog: DFT CHECK VALVE CATALOG
