FELUWA MULTISAFE® double hose-diaphragm pumps
for abrasive, aggressive and toxic media

Excess-pressure relief valve

Each pump head is provided with an individual, easily accessible excess-pressure relief valve in the hydraulic fluid. This valve is set to the exact nominal pressure required during the works test run of the pump.

If an over-pressure situation becomes evident in the hydraulic fluid, i.e. due to a closed discharge sluice valve, the excess-pressure relief valve will open, thus relieving hydraulic fluid (VÜ) into the hydraulic oil reservoir. From this reservoir the oil is automatically returned into the pump chamber via the leakage compensating valve. The relief valve protects the pump as well as the gearbox from overload which may arise from an erroneously closed isolating valve or from a blocked discharge pipe etc.

Excess-pressure relief valves are also available with type approval and with lead seal.

Excess-pressure relief valve using the example of a MULTISAFE® pump.


  • VF = volumetric displacement
  • VK = volumetric piston displacement
  • VL = continuous bleed volume
  • VLE = leakage compensation volume (via make-up device)
  • VSM = volumetric hose-diaphragm displacement
  • VÜ = volume diverted into the oil storage tank via the pressure relief valve