Constant pressure relief role: in the quantitative pump throttling regulation system, the quantitative pump provides a constant flow. When the system pressure increases, it will make the flow demand decrease. At this time, the relief valve opens, so that excess flow overflow back to the tank, to ensure that the relief valve inlet pressure, that is, the pump outlet pressure is constant (the valve port is often opened with the pressure fluctuations). Pressure stabilizing effect: the relief valve is connected in series in the return oil circuit, the relief valve generates back pressure, and the smoothness of moving parts increases.
System unloading effect: the remote port of the relief valve is connected in series with a small flow of solenoid valves, when the solenoid is energized, the remote port of the relief valve through the tank, this time the hydraulic pump unloading. Relief valve at this time as unloading valve use.
Safety protection role: the system works normally, the valve is closed. Only when the load exceeds the prescribed limit (system pressure over the regulated pressure) when the opening of the relief, overload protection, so that the system pressure does not increase (usually so that the regulating pressure of the relief valve than the system's higher working pressure of 10% to 20%).
Practical applications are generally: for unloading valve, as a remote regulator, as a high and low pressure multi-stage control valve, as a sequence valve, used to generate back pressure (strung on the return line). Relief valves generally have two structures: 1, direct-acting relief valve. 2, pilot-operated relief valve.
The main requirements of the relief valve: large pressure range, small pressure deviation, small pressure oscillation, sensitive action, large overload capacity, low noise.