Rexroth DBW20 solenoid operated unloading pressure relief valve is controlled by a solenoid, which is on or off depends on the solenoid energized or de-energized and the pilot pressure is controlled by the main pilot relief valve
The upper chamber pressure of the pilot relief valve of the main valve is controlled by the pilot valve, if the pilot relief valve normally works, the upper chamber of the main valve keeping the presetting pressure.
Rexroth DBW20 Solenoid Operated Unloading Pressure Relief Valve
Rexroth DBW20 Solenoid Operated Unloading Pressure Relief Valve
The solenoid will open if the hydraulic system pressure reaches the set pressure, on the one hand, it can drain the excess flow back to tank and maintaining the system pressure as set value. The solenoid valve maintain or unload the pressure, the main valve is to respond the solenoid valve, when the main valve port open to the right size when it is unloading , the excess flow is released out but also not affect the system pressure .
If the solenoid valve without pressure, there is no pressure in the upper chamber of the main valves, therefore, the poppet in the main valve is open at the largest size to release the pressure to the oil tank and not to system.
Rexroth DBW20 solenoid operated unloading pressure relief valve is connected with the main pilot valve the pressure in the upper chamber of the main valve is same with the connected part , this connected parts is no pressure unloading , the system does not require unloading through solenoid valve when the it is closed, which will return the pressure to the oil tank by the main valve.
