The DBD pressure relief valves are direct operated poppet valves.They are used to limit the pressure in a hydraulic system. The valves mainly consist of sleeve, spring. poppet with damping spool (pressure stages 2.5 to 40 MPa) or ball (pressure stage 63 MPa) and adjustment element. The setting of the system pressure is infinitely variable via the adjustment element.The spring pushes the poppet onto the seat. The P channel is connected to the system.The pressure present in the system is applied to the poppet area (or bail)

If the pressure in channel P rises above the valve set at the spring, the poppet opens against the spring. Now pressure fluid flows form channel P into channel T. The stroke of the poppet is limited by a pin. In order to maintain a good pressure settings over the entire pressure range the pressure range is split into 7 pressure stages. One pressure stage corresponds to a certain spring for a maximum operating pressure which may be set with it.