Sealing Performance Analysis And Optimization Of High-pressure Metal Hardsealing Fixed Ball Valve

Because of the ball valve's advantages of small fluid resistance,convenient operation,quickly opening and closing,good sealing and high reliability,it can be widely used in chemical industry with harsh conditions such as petrochemical,coal.The motion,static and direction of the fluid in the transfer process is determined by the on-off state of the ball valve.As the important role in the oil and transmission channels,the ball valve,with it's sealing,using security and stability,determines whether the whole transmission device can run in normal operation state.Due to the raw materials of petrochemical,coal and other chemical industries have corrosive,large particles and other characteristics,the industries put forward higher requirements to ball valve on high pressure,high temperature,corrosion resistance,friction and other properties.However the traditional soft seal is harder to meet the demand.Thus,the high-pressure metal hard seal ball valve with metal seat is better suited to petrochemical,coal chemical industry.The metal hard seal ball valve uses spring preload and fluid pressure to allow the valve seat and the ball to come into close contact to achieve the ball valve seal.It is meaningful to study the sealing pressure and the contact problem of the two pairs of contact surfaces of seal vice and explore the sealing of the ball valve,and it is also the purpose work of this paper.In this paper,the sealing principle and the nonlinear contact algorithm and computer analysis software are used to analyze and optimize the sealing performance of the ball valve:1)To calculate sealing pressure,permissible pressure and necessary pressure of the seal vice.This work,combining with theoretical and practical environment,explore the principle of sealing and nonlinear contact algorithm.2)In this work,the metal hard seal ball valve of Class1500 NPS14 was used as the research object.A three-dimensional model for the parts and a assembly diagram of ball valve has been built by Solidworks,and simplified by ANSYS Workbench.Furthermore the model was analyzed in finite element method.3)Sealing finite element analysis shows that there are deformations in some partsof the ball and seat of the ball valve,it could cause a certain amount of leakage.So,the impact of the elastic contact modulus,ball radius and seat size of the ball valve on the leakage has been explored in this work.3)In order to optimizing the structure of the ball valve,two options has been proposed :one is increasing the length of the valve seat L1,another is slotting in the seat.It is shows that both methods can improve the sealing of the ball valve by Finite element analysis.