What are the basic uses of relief valves?

Loosen the locking nut of the relief valve and turn the pressure adjustment handle to adjust the pressure of the hydraulic system. Turning clockwise increases the pressure, turning counterclockwise decreases the pressure. 

1. Pressure regulating overflow

In a hydraulic system that uses a quantitative pump to supply oil, in order to meet the needs of the workload, the hydraulic system requires a certain pressure value. The system needs to "pressure regulate", that is, the working pressure of the hydraulic pump needs to be determined; on the other hand, when the actuator does not When so much flow is needed, and the flow rate supplied by the quantitative pump is certain, the excess oil can only be overflowed through the overflow valve and drained back to the tank. Otherwise, the system pressure will rise very high due to the excess flow. Therefore, during the quantitative pump In the pump hydraulic pump source system, the relief valve plays the roles of "pressure regulation", "pressure limiting" and "overflow".

2. Security protection

In a hydraulic system with a variable pump as the power source, the flow rate of the pump can generally change with the load, and there is little excess flow. The working pressure is determined by the load. Only when the pressure exceeds a certain preset pressure, the overflow will occur. The overflow is opened only after the flow valve is opened, so that the system pressure no longer rises, protecting the system from overload and playing a safety role.

3. Boost or unload the pump as needed

At this time, an electromagnetic relief valve is used in the hydraulic system. When the electromagnet is energized, the external control port of the relief valve is connected to the oil tank, thus enabling the pump to be unloaded.

4. Remote voltage regulation and two-stage voltage regulation

Install a remote pressure regulating valve at a convenient location. When the external control port The oil chamber in the upper chamber of the relief valve spool is connected to the external control port X. When the solenoid valve is not energized, as long as the adjusted oil pressure reaches the adjustment pressure of the remote pressure regulating valve, the main valve core can lift the overflow (its pilot valve no longer plays a pressure regulating role), that is, remote pressure regulation is achieved. When the solenoid valve is energized and works in the left position, the pressure is regulated by the main relief valve. When the solenoid valve is energized and works in the right position, the pressure is regulated by the remote pressure regulating valve. That is, the hydraulic system has two working pressures, which is called dual-stage pressure regulation.