What could be the reasons for the failure of the speed control system of the 315-ton four-column hydraulic machine?

1. 1.The throttle port of the throttle valve is blocked, causing the flow rate to be not small or unstable;
2. 2.The spring of the speed control valve is too soft, the pressure difference before and after the throttle valve is too small, causing the flow rate of the speed control valve to be unstable;
3. 3.The pressure reducing valve in the speed control valve is stuck, causing the pressure difference before and after the throttle valve to change with the external load;
4. 4.The pressure reducing valve in the speed control valve is stuck in the open position, and the flow rate through the throttle valve decreases when the load increases;

The advantage of the hydraulic speed control valve is good flow stability, and the disadvantage is large pressure loss. It is often used in the throttle speed control system of fixed pumps, has large load changes and high speed control accuracy, and is sometimes used in the volume adjustment speed control hydraulic system supplied by variable pumps. In the throttle control hydraulic system of fixed pump oil supply, it can be combined with the pressure reducing valve to form a series of throttle valve and parallel throttle valve speed control circuits.