Pressure relief valve, direct operated, type DBD ... 10The DBD pressure relief valves are direct operated, used to limit the pressure of hydraulic system. It comprises the sleeve (1), spring (2), poppet spool with damping (3) (pressure stages 2.5 to 40MPa) or ball spool (4) (pressure stage63 MPa) and pressure adjustment element (5). The system pressure may be set infinitely by the adjustment element. The spring (2) presses poppet spool (3) onto the valve seat. The channel P is connected to the system and the system pressure affect on the area of poppet (or ball) spool.If the pressure in channel P rises excess the value set at the spring (2), the poppet spool (3) or ball spool (4) opens against the spring (2). Then the pressure oil flows from channel P to channel T. And the stroke of the spool is limited by spin shaft (6).To gain accurate setting value within the whole pressure range, the pressure scope is divided into 7 pressure ratings, and every rating has a corresponding spring which may be set maximum pressure.DBD...L10.pdf