Analysis of why the relief valve of four-column hydraulic press fails to regulate pressure

The relief valve of four-column hydraulic press sometimes fails to regulate the pressure during operation. There are two cases of pressure regulation failure of pilot relief valve: the first dispatching pressure regulator can not be established. Or the pressure doesn't reach the set value. The second is to dispatch the handwheel pressure does not drop, and will continue to increase the pressure, will lead to pressure failure, in addition to the valve core radial clamping, but also the following elements to pay attention to:

The damping hole on the heart of the main valve of the four-column hydraulic compressor is blocked, and the liquid pressure cannot be transmitted to the upper chamber of the main valve and the front chamber of the taper valve, and the pilot valve loses the scheduling effect of the pressure of the main valve. Because there is no oil pressure in the upper chamber of the main valve and the spring force is very small, the main valve becomes a direct-acting relief valve with a small spring force. When the pressure of the oil inlet chamber is very low, the main valve heart will open the overflow, and the system will not be able to establish pressure. The pressure regulating spring deformation or selection fault, excessive leakage in the valve or excessive wear of some taper valves (a basic type of component failure) of the pilot valve are the basic elements of the pressure can not reach the set value.

Second, the damping hole on the taper seat of the pilot valve of the four-column hydraulic press is blocked, and the oil pressure is not transmitted to the taper valve, and the pilot valve loses the scheduling effect of the main valve pressure. After the damping hole is blocked, under the daily pressure, the taper valve can not open the oil discharge, there is no oil activity in the valve, the oil pressure in the upper and lower chambers of the main valve is equal, the main valve heart is closed under the effect of the spring force, and the pressure before the relief valve rises with the increase of the load. When the actuator moves to the end, the external load increases indefinitely, and the pressure of the system increases indefinitely.

If the long-distance control port of the relief valve of the four-column hydraulic press is connected with a pressure regulator, it is assumed that the control port is blocked, the pipeline between the control port and the pressure regulator is long, and there is air, the pressure scheduling is abnormal.

The sealing ring inside the relief valve of the four-column hydraulic press is damaged, the main valve core and the cone valve core wear (a basic type of component failure) are too large, which constitutes a serious leakage inside the surface and makes the dispatching pressure unstable (explanation: stable and stable; No change), or even work normally.