At hydraulic power plants where short closing times are needed for the turbine wicket gates and needles, our pressure relief valves can be integrated in order to protect the plant from unit overspeed and excessive pressure rise. When a unit trips, the pressure relief valves are opening immediately and simultaneously, and – as a bypass – re-direct the flow of water around the turbine and into the tailwater pool. Afterwards, when it is safe to do so, the valve closes at a slow and controlled rate.

Pressure relief valves are built as poppet seat valves with an opening tendency and hydraulic drive. The shape of the internal wetted components is crucial for cavitation-free and vibration-free operation. Our valve housing and inlet elbow are manufactured from high quality steel, while the gaskets and the pistons are made from stainless material.