Research on Pressure Characteristics of Two-Speed Buffer Valve Pushing System

The positioning control of the hydraulic support pushing system in the fully mechanized mining face is the key technical support to realize intelligent mining. The opening and closing of the existing support switch reversing valve will cause a sudden change in the system pressure and flow under the conditions of high pressure and large flow, which will affect the life of the components, the precision, and stability of the actuator movement. To solve the problem, the structure of a two-speed buffer valve for the hydraulic support pushing circuit is designed. Firstly, the pushing system is analyzed theoretically, and the characteristics of the flow field in the valve and the applicable working conditions are simulated. Then, an experimental platform was built to test the improvement effect of the two-speed buffer valve on the characteristics of the pushing system. Finally, the pressure, flow, and positioning characteristics of the two-valve series pushing system under different flow rates are studied by the test results. The research results show that when the two-speed buffer valve is used, the pressure and velocity change thresholds of the system are reduced, which reduces the pressure fluctuation in front of the valve and its effect on the system pressure. At the same time, under a different system flow, the downstream pressure characteristics of the valve are improved, and the steady-state pressure anti-interference is enhanced. The positioning error of the system is reduced under different flow rates. The effectiveness of the scheme is verified by the test, which provides a basis for the optimization of the downhole valve control cylinder scheme and the subsequent valve.