In compressed air systems to limit the output pressure, but also for changed but increased input pressure.

The compressed air entering at port 1 flows over the open valve seat to port 2, where it also acts on the spring-loaded diaphragm. If the set spring force is reached by the compressed air acting on the diaphragm, the valve inlet closes so that no more compressed air can flow to port 2. Pressure losses due to leaks on the outlet side are automatically compensated by the pressure limiting valve. If the pressure are port 2 rises above the set value, the surplus compressed air is discharged to atmosphere through the valve outlet. When exhausting the inlet side (port 1), the pressure opens the outlet side (port 2) of the valve inlet. The pressure relief allows the diaphragm to return to its initial position. Port 2 is exhausted to port 2 via the open valve inlet.