A valve installation helped dealing with the continuous failure of butterfly valves that resulted in continuous unwanted downtime.
By Nicole Singh, AVK Valves Southern Africa
A prominent mining house was faced with a persistent problem of valve failures at its crucial water reclamation plant, and sought the expertise of AVK Southern Africa through one of the valve manufacturing company’s local distributors, Maduba Mining Supplies, to provide a lasting solution.
Built in 2016, to process used mine water, the water reclamation plant was consistently plagued by problematic butterfly valves that kept failing and could barely last six months. As explained by the customer, the reason was that the butterfly valves were twisting, and would eventually break off due to scale build-up inside the valve.
Consequently, the valve liners protruded out, thus preventing the valves from closing properly, which in turn caused the actuator to trip over torque. The company needed to have a person on standby just to get the system back online once the actuator had tripped.
Putting our valves to the test
After visiting the site to investigate, AVK Southern Africa’s Pieter Swanepoel recommended a Wouter Witzel EVS valve for testing. Having put the valve through its paces for a month, the plant maintenance foreman called Swanepoel to report that the Wouter Witzel EVS had failed, saying that the disc had broken free from the shaft and was “spinning” in the pipeline.
Based on his experience with the product, Swanepoel was incredulous about the claimed EVS failure and insisted to be on site when they removed the valve from the line. Once the valve was removed, it was taken to a test bench, where the foreman opened and closed it, only to discover that it was functioning properly.
The plant foreman, who was initially convinced that the valve had failed, was astounded as it did not trip even once during the entire testing period. It even ran at a lower torque output than all the other valves on site.
Central to this capability is the fact that the EV valve range (including the EVS) is equipped with a vulcanised liner. The vulcanisation process bonds the rubber onto the body of the valve by means of high temperature and high pressure, eliminating any space between the body and the liner where corrosion or erosion can take place. This keeps the torque low and constant over the lifetime of the valve. The vulcanised layer stays in place and gives a drop-tight seal every time.
Immediate improvements
The valve has thus provided a lasting solution for the customer. Since its installation some two years ago, the test valve has completed a whopping 200,000 cycles, and counting.
Not only has the valve lasted four times longer than the previously specified valve, but it also uses a smaller actuator to open and close, thus reducing running costs. The valve opens and closes approximately once every five minutes.
The Wouter Witzel EV range has an impeccable track record and has continuously proven itself, not only in outlasting its competition, but offering significantly lower cost of ownership. Having experienced these benefits first-hand, the mining house is now converting the whole plant for Wouter Witzel butterfly valves.
