Finite Element Analysis And Optimization Of The Structure Of Hard Sealing Ball Valve

Hard seal ball valve sealing mask is high hardness, which can sustain high temperature and line pressure, with better throttle and regulating performance, anti solid particles, flashing and cavitation damage, and has good sealing performance and wear resistance. In Coal chemical industry, polysilicon, refining, offshore platform and power plants, the metal sealing ball valve has widely applied. In the requirements for tight shutoff, high temperature and high pressure, switch quickly and under the condition of solid particles containing medium, metal hard seal ball valve is the preferred valve types.The seal fixed ball valve appears sealing surface leakage failure, fatigue wear stem ball extrusion deformation or sphere Coating damaged in practical condition. However, the analysis of the design of the theory of focus in the optimization design of structure theory or a single component analysis and the failure of local components assembly contact analysis and design size and contact should force research are rare.Therefore, the thesis accordingly to introduce a three-piece hard sealing fixed ball valve designed by Fangzheng Co. Ltd. as the research object combined with nonlinear contact theory, using numerical simulation method on the seal fixed valve stem contact with the ball, valve seat and ball contact components as the following several aspects of research and analysis:1. Take the NPS 12, CLASS600 seal fixed on the ball valve for example, using Pro/E software to establish hard seal fixed on the ball valve components of the 3D model and assembly model. Through the ANSYS Workbench software analyzes nonlinear contact between the ball and stem parts.2. Three ways of ball and stem contact optimization are proposed, and the model is established respectively. The maximum stress under different structures is determined, and a suitable solution is selected.3. In the selected optimal scheme, the maximum contact stress is the objective parameter, and the relative sensitivity analysis is carried out by using the contact position of the sphere and the valve stem as the design variables.4. Contact parts of the valve seat and the sphere of nonlinear contact analysis, with the opening of the valve seat and ball contact stress change rules are obtained. Analysis of the open degree of 50% and stress the maximum opening of the equivalent stress, deformation and displacement, and on the seat with deflection and deflection are compared, simultaneously analyzed stress maximum opening deflection under the valve seat and ball on the contact stress distribution;5. Analyze the influence regulations of the valve seat sealing surface width and seat deflection angle on the maximum equivalent and maximum displacement of the sealing surface of the valve seat; Improving the contact part of the valve seat and ball, to reduce the contact stress and meet the requirement of the application.