Pressure relief valves

At hydraulic power plants where short closing times are needed on turbine guide vanes and jets due to technical reasons, pressure relief valves are integrated into lines in order to hinder mechanical overrev and excessive pressure increase. When a stop command is sent to the turbines, they open immediately and simultaneously and – as a bypass – re-route the corresponding volume of water directly into the tailwater pool. Then the pressure relief valve is closed for the predefined time frame.

Pressure relief valves are built as a poppet seat valves with an opening tendency and hydraulic drive. The optimal form for the water-guidance components is crucial for operation that is as free from cavitation and vibration as possible. Housing and inlet elbow are made from high quality steel, while the gaskets and the pistons are made from stainless material.


  • Reliably hinder mechanical overrev and excessive pressure increase
  • Minimised cavitation and vibration
  • High quality steel


Hydropower brochure