Performance Analysis And Structure Optimization Of Metal Sealing Ring In Ultrahigh Vacuum Valve

As the key sealing part of the ultra-high vacuum valve,the performance of the metal sealing ring will directly affect the healthy operation and work efficiency of the ultra-high vacuum system equipment.With the vigorous development of semiconductor chip,special smelting,vacuum coating and other industries,the application of ultrahigh vacuum valves has greatly expanded,and the metal sealing ring is also facing higher performance requirements and challenges.Therefore,it is particularly important to improve the comprehensive performance of the metal sealing ring in the ultra-high vacuum valve through performance analysis and structural optimization.In this paper,the metal sealing ring of a DN40 all-metal ultra-high vacuum Angle valve is taken as the research object.Based on its structural stress and sealing mechanism,the basic laws of the sealing process are analyzed,and the main control parameters that affect the sealing performance are given.Then,the finite element model,the influence of parameters on the performance,the multi-objective optimization of the structure and the vacuum test of the Angle valve are studied deeply.After nonlinear processing of the simplified model,the stresses of the metal seal ring in different states is analyzed;Then,based on the von-Mises stress and contact stress,the influence of external factors and structural parameters on the sealing performance of the metal seal ring is studied.The former includes temperature,medium pressure difference and working load,the latter includes arc radius r,plane height h,plane width g,plane tilt angle θ and half apex angle α.After that,the compression and rebound characteristics of the metal seal ring are simulated,and the performance prediction equations of the metal seal rings with different diameters are given.According to the performance law of the metal sealing ring and the target of vonMises stress and contact stress,the optimized parameters are screened out and the multiobjective optimization problem is established;Then,basing on the response surface method and the Box-Behnken design principle,through reasonable samplings of the experiment with 3 factors and 3 levels,the second-order response surface models of the metal seal ring between its structural parameters and evaluation targets are established,and the accuracy of both models is evaluated;After that,the genetic algorithm NSGAII is used to solve the multi-objective optimization problem of the metal sealing ring on the MATLAB-based platform Plat EMO.And the final optimization plan is selected according to the actual situation.Finally,the two stress levels of the metal seal ring before and after the optimization are compared by simulation.Then,the technical indicators of the angle valve are checked through the vacuum experiments,and it is found that the experimental results are consistent with the simulation conclusions,which verify the rationality and correctness of the multi-objective optimization scheme.