In 2015, a wastewater treatment facility began reviewing alternatives to its existing design in an effort to resolve a water hammer issue and considered the use of wafer style axial flow check valves. Axial flow check valves were considered due to the ability to minimize and/or reduce the effects of water hammer based on the difference between an axial flow and dual disc trim.
To understand the improved performance of an axial flow check valve in minimizing water hammer, you must consider the fundamental difference in the trim design. Just as ball valves, globe valves, gate valves, etc. have different flow characteristics, so do check valves. Check valves can be classified into two basic categories, swing checks and axial flow. In the case of axial flow check valves the trim moves parallel to the axis of the flow path. Only non-slam silent check valves are designed this way.
A comprehensive case study was put together detailing how the wastewater treatment facility resolved the following hammer problems:
- Check valve spring failure every 2-3 months
- Repair and replacement of check valve every 3-4 months
- Increased routine for tightening loosened flanging due to hydraulic shock in system
- Retuning of instrumentation due to hydraulic shock in system
- Loss of capacity due to increased maintenance routine
Download the case study to learn more about DFT Check Valves or contact the team at Campbell-Sevey.