Analysis And Optimization Of Floating Seat-Gate Seal Structure For Flat Gate Valve Of Pipeline

Pipeline flat gate valves are widely used in all kinds of gas,oil and other transportation pipelines and the demand is huge.The "floating seat-gate" seal structure is the main seal structure of the pipeline flat gate valve.At present,the sealing structure design is based on the experience design,which leads to the increasing of its leakage rate and the increasingly prominent phenomenon that its service times are gradually shortened,threatening people’s life and property safety.Therefore,the research on the sealing structure has important academic value and engineering significance.In view of the above problems,the “floating seat-gate” sealing structure is studied by combining theoretical analysis with finite element analysis software.The influence rule of the main structural parameters on the sealing performance of the seal structure is obtained,and then the seal structure is optimized.The main work of this dissertation is as follows:(1)The sealing structure of pipeline flat gate valve“ floating seat-gate” is analyzed by finite element method.Based on the sealing mechanism of NSP6-Class300 pipeline flat gate valve,the deformation,stress and contact analysis of the sealing structure were conducted by using the professional finite element analysis software ANSYS Workbench,and the specific reasons for the failure of the sealing structure were obtained.(2)The influence of structural parameters of floating seat on sealing performance of“floating seat-gate”sealing structure is studied.Through theoretical calculation and finite element analysis of the method of combining the spring hole quantity,sealing surface of the float valve seat diameter,the structure of the seal face width and the thickness of four parameters on the model the influence law of pipe plate gate valve sealing performance,provide the basis for the optimization design of the structure of the seal,also can be to optimize the design of other types of similar valve to provide technical reference.(3)Structural of floating seat is optimized design.On the analysis of the“floating seat-ram” seal structure,on the basis of failure cause,combined with the four parameters on the influence law of the structure of the sealing structure,the floating valve seat structure optimization and improvement: floating seat spring hole number instead of eight,and sealing surface to 165 mm in diameter,sealing surface width is changed to 6 mm,floating seat thickness to 35.5 mm.After improvement,the friction torque and equivalent stress of the sealing surface of the sealing structure are obviously reduced,and the sealing performance of the sealing structure is remarkably improved.