Outstanding performance and zero maintenance with reliable Flowrox pinch valves

Nov 30, 2021

Reliable Flowrox™ high performance PVE pinch valves proved to be a perfect solution for a power generation water treatment plant located in Mpumalanga, South Africa. Six years after the installation of PVE pinch valves in power generation plant no maintenance has been required.

In early 2012 Valmet and Maduba Mining presented Flowrox pinch valve technology at the South African power generation water treatment plant. The plant had outdated Saunders type diaphragm valves which had to be replaced. The old technology was costly to maintain and with regular unplanned maintenance intervals, resulting in high costs. It was time for a proven performance solution.

Identifying causes of problems to offer better solutions

Valmet and Maduba Mining experts visited the site to find out what was causing problems and gather necessary process requirements to offer the most suitable solution. The main problem was not only highly corrosive application. There was substantial crystallization which prematurely damaged diaphragms on Saunders type valves causing them to fail prematurely, creating excessive and expensive downtime.



"Flowrox PVE valves are 100% tight shut-off even if solids have built up on sleeve’s inner surface. When compressed, any crystallized particles flake off sleeve’s surface and arewashed away by the process medium. The sleeve is the only part in contact with the medium, which is crucial in such corrosive applications. It is the only replaceable part as there is no contamination of bearings or seals which saves money on spare parts,” explains Neil Venter, Area Sales Manager of Flowrox products in South Africa.

Flowrox pinch valves allow adjustable shut-off control Flowrox valves at a power generation water treatment plant

This application required a reliable isolation valve. “Valves with pneumatic actuation include a mechanical spring which keeps the valve open or closed in case of a failure. Based on process conditions, our customers can pick an option which best suits their needs,” adds Venter. In the event of compressor failure, the valve would cycle open or closed depending on the control philosophy: without obstruction in open position and without leakage in closed position. After examining process conditions, Valmet suggested to test Flowrox PVE high performance pinch valves.

Successful test period: We choose Flowrox valves

After three months of successful testing of Flowrox PVE valve, Valmet experts visited the power generation water treatment plant to check its performance and get feedback from the plant personnel. It turned out the Flowrox valve was performing so well, requiring no maintenance, that the plant personnel had forgotten about the valve as it presented no problem.


Excellent performance of Flowrox PVE valve led to plant’s decision in 2013 to standardise on Flowrox pinch valves. Since 2013 most of the old diaphragm valves were replaced by Flowrox PVE valves.

Outstanding performance and zero maintenance with reliable valves

After six years the first supplied Flowrox PVE valve is still working well and has required zero maintenance. The Power Generation Water Treatment Plant located in Mpumalanga is extremely satisfied with outstanding performance of Flowrox valves.

To share the good experience, Valmet presented its solutions on site to other power stations at the Power Utility Water Treatment Forum. Through cooperation, hard work, dedication and quality products, Valmet delivered the best solution to minimize downtime, save money on spare parts and offer reliable products.

Text originally published in 2018, and slightly updated in April 2022, due to the company name change to Valmet. As of the 1st of April 2022, Flowrox brand belongs to Valmet.

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