Structural principle of safety relief valve

Structural Principle

The safety relief valve has a remote control port. If the remote control port is connected to another remote pressure regulating valve through an oil pipe (the structure of the remote pressure regulating valve is the same as the pilot control part of the overflow valve), adjusting the spring force of the remote pressure regulating valve can adjust the hydraulic pressure at the upper end of the main valve core of the overflow valve, thereby achieving remote pressure regulation of the overflow pressure of the overflow valve. However, the maximum pressure that can be adjusted by the remote pressure regulating valve shall not exceed the adjustment pressure of the pilot valve of the overflow valve itself. When the remote control port is connected to the oil tank through a two position two way valve, the pressure at the upper end of the main valve core approaches zero, and the main valve core moves up to the highest position. The valve port is opened very large. Due to the soft spring of the main valve, the pressure at the outlet of the overflow valve is very low, and the system oil flows back to the oil tank through the overflow valve at low pressure, achieving unloading.

 

Working Principle

When the safety relief valve is working, it uses the pressure of the spring to adjust and control the pressure of the hydraulic oil. When the pressure of the hydraulic oil is less than the required working pressure, the valve core is pressed by the spring at the inlet of the hydraulic oil. When the pressure of the hydraulic oil exceeds its allowable working pressure, which is greater than the spring pressure, the valve core is jacked up by the hydraulic oil, and the hydraulic oil flows in and out of the outlet back to the oil tank.