Is shocking water hammer hammering your production?
Visiting our valued clients to discuss upgrading a water treatment plant is always an interesting experience, but often the importance of addressing peripheral requirements needs to be highlighted.
Below, we discuss a classic example of a client wishing to upgrade a water treatment plant but found they had to firstly overcome water hammer issues.
When recently inspecting a Granular Activated Carbon (GAC) water filtration system for a soft drink manufacturer, our technician noticed sudden pipe vibrations and leaking filters.
In this application the mains water supply is pressurised through an activated carbon filtration system to remove chlorine, and then is fed to the process lines, a common step for beverage producers.
The site technician discovered that each time the downstream actuated valves changed position, the resultant water hammer caused costly downtime to production, due to the need to fix up leaks and failed cartridge filter pipework.
How to prevent water hammer in a water treatment application:
Replace the fast closing pneumatic actuated valve with a slow-close electric actuated valve. (It’s the sudden shut off that causes the water hammer pressure spikes).
Substitute swing and dual disc check valves with spring check silent non-return valves. (Spring check valves close before flow direction is reversed; it’s the water bounce back that does the damage).
If it’s not possible to eliminate the causes of water hammer you can still reduce the effects by taking the following actions:
Do install ~60L pressure bladder tanks on the end of a pipe run/leg – this is to absorb the full brunt of the shock. Replace an elbow with T piece.
Install water hammer arrestors. (Like a bladder tank but with a compressed air pocket instead of a bladder).
Install pressure relief valves to protect tanks and equipment. (Note: these don’t absorb the shock they just allow the surge of pressure to escape at a set pressure).
For more technical detail, download the free e-book “Understanding Water Hammer” below, which contains excellent tips on preventing water hammer (courtesy of DFT Valves, USA).