Design And Experiment Research On The Large Flow Pilot-Operated Check Valve

With the rapid growth on the high yield and high efficiency coal face, the large flow pilot-operated check valve in hydraulic support developing to high pressure and high flow is required as well as more reliability and longevity. Unloading of the stent, the large flow pilot-operated check valve reverse opens, so a large number of high water-based emulsion in the inferior vena of column quickly overflow. Meanwhile, the system often occurs a huge impact. The severe pressure impact not only damages hydraulic equipment but also results in the pipeline interface fracture that could cause a serious accident. For lack of direction of design philosophy and backwardness of design methods, meanwhile, being short of the test-bed of large flow pilot-operated check valve, there is a big gap in the products of large flow pilot-operated check valve between home and abroad. In this thesis, to address this issue, the design methods and experiment of large flow pilot-operated check valve in the hydraulic support will be studied. The main works in this thesis are as follows.First the structure and key parameters are initially designed based on the large flow pilot-operated check valve of FDY800/50. The 3D model is established respectively, and hydrodynamics analysis of its inner flow field is made with software FLUENT. Fluid-solid coupling analysis of the poppets is carried out with ANSYS Workbench. The hydrodynamics rule and stress and deformation of the poppets are studied on different half cone angle and different opening degree of the large flow pilot-operated check valve. This study shows that the larger the opening degree and half cone angle are, the smaller the pressure impact and fluid energy losses are in unloading of the stent. And the stress and deformation of the poppets are also smaller, which meet the allowable stress of 45 steel.Then the simulation model is established in the AMESim software based on the dynamic characteristics mathematical model that was done before. The dynamic characteristic curves are got through the simulation, and the impacts of different half cone angle and different control pressure on the dynamic characteristics have been compared and analyzed. The simulations reveal that increasing the control pressure and half taper angle of the small poppet can effectively reduce the unloading pressure impact and improve its stability during the opening process, which significantly improves the dynamic characteristics of the large flow pilot-operated check valve.Finally the large flow pilot-operated check valve is tested on the new type testing system. The working process and its dynamic characteristic are studied through the testing result. Furthermore, the validity of the simulation is validated by comparing the simulation results with the experimental results. The results show that its dynamic characteristics will be better with the increase of the half cone angle and the control pressure.Putting the different half cone angle as a principle line, the design methods of large flow pilot-operated check valve are systematically established through the structural design, the fluid-solid coupling analysis, dynamic characteristic simulation and the testing research. It provides new opportunities for design and check of valves used by support through the fluid-solid coupling analysis.