Pressure relief valve

The valve restricts the pressure at port P to the set value compared with the pressure at T.

If the differential pressure (dp=pP-pT) times the cross-sectional area of the sealing cone exceeds the spring force, the sealing cone lifts out of the seat and allows oil through to port T. The valve closes again once the pressure in port P drops again. The cushioning piston acts like a shock absorber to increase stability during the control response. The spring pretension can be adjusted at the hand wheel. Oil flows through the non-return valve if the pressure at port T is greater than at P.

Adjustable parameters

Pressure relief valve
Designation Range Default value
Opening pressure 0 ... 40 MPa 3
Pressure regulation range 0.01 ... 10 MPa 3.5
Hydraulic resistance 1e-6 ... 1000 bar.min2/l2 0.08
Non-return valve
Designation Range Default value
Hydraulic resistance 1e-6 ... 1000 bar.min2/l2 0.06

Failure models

Failure model Description
Check valve always closed The check valve is always closed.
Check valve always open The check valve is always open.
Linear scaling Instead of the nominal value u the lineal scaling y = slope_err*u+ offset_err is used.
Parameter
Designation Range Default value
Offset -40 ... 40 MPa 0
Slope 0 ... 10 0.5