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Relief valve


Constant pressure overflow function: in the quantitative pump throttling adjustment system, the quantitative pump provides a constant flow. As the system pressure increases, the flow demand decreases. At this time, the relief valve is opened, so that the excess flow overflows back to the fuel tank to ensure the inlet pressure of the relief valve, that is, the pump outlet pressure is constant (the valve port often opens with pressure fluctuations).

Voltage stabilization effect: The overflow valve is connected in series on the oil return road, the overflow valve generates back pressure, and the stability of the moving parts increases.

System unloading function: a solenoid valve with small flow rate is connected in series with the remote control port of the relief valve. When the electromagnet is energized, the remote control port of the relief valve is connected to the fuel tank, and the hydraulic pump is unloaded at this time. The relief valve is now used as an unloading valve.

Safety protection: When the system is working normally, the valve is closed. Only when the load exceeds the specified limit (the system pressure exceeds the set pressure), the overflow is turned on, and overload protection is performed to prevent the system pressure from increasing (usually, the set pressure of the overflow valve is 10% to 20% higher than the maximum working pressure of the system). ).

In practical applications, it is generally used as an unloading valve, as a remote pressure regulating valve, as a high and low pressure multi-stage control valve, as a sequence valve, used to generate back pressure (in series on the oil return road).

There are generally two types of relief valves: 1. Direct-acting relief valve. 2. Pilot-operated relief valve.

The main requirements for the relief valve: large pressure regulation range, small pressure regulation deviation, small pressure swing, sensitive action, large overload capacity, and low noise.