Pilot-operated proportional pressure relief valve

The pilot operated pressure relief valve consists of a pilot stage with poppet valve and a main stage with control slide valve. The pressure at connection P acts upon the pilot poppet via a drilling in the control slide valve.

If the force of the proportional magnet is greater than the pressure exercised at connection P, then the pilot stage remains closed. A spring keeps the main stage poppet valve closed and the flow rate is null.

If the force, that the pressure exercises, exceeds the closing force of the pilot poppet, then this opens. A lower flow rate develops from connection P to connection Y. The flow of fluid causes a pressure loss at the throttle valve inside the control slide valve. Thus the pressure at the spring side is lower than the pressure at connection P. Due to the pressure difference, the control slide valve opens so far until the spring force re-establishes an equilibrium of forces and the valve is perfused from P to T.

The control voltage must be between 0 V and 10 V. The minimum nominal pressure defines the opening pressure at the pilot stage via the spring force at 0 V. The maximum nominal pressure defines the opening pressure at 10 V. The hydraulic resistance relates to the completely opened main stage leading edge.

Adjustable parameters

Designation Range Default value
Min. Opening pressure 0 ... 40 MPa 0
Max. Opening pressure 0 ... 40 MPa 10
Pressure regulation range 0.01 ... 10 MPa 2
Hydraulic resistance 1e-6 ... 1000 bar.min2/l2 0.05