Research On Sealing Performance Test Technology Of Metal Wound Gasket Under High Temperature And Pressure Environment

Metal spiral wound gaskets are used as sealing elements at the joints of pressure-bearing pipelines in the process industry.They have been used in high temperature,pressure,and corrosion conditions for many years,and easy seal failure to prone to leaks,causing environmental pollution and major safety accidents.The sealing performance of the gasket is a comprehensive performance,which is mainly characterized by the leakage rate,and good compression resilience is an important guarantee for the realization of the gasket sealing.At present,the domestic and foreign countries mainly focus on theoretical research on the high-temperature sealing performance of gaskets,and there are few researches on experimental tests under high-temperature pressure environments.Combining actual engineering research projects,this paper takes the test of the sealing performance of metal spiral wound gaskets under high temperature and pressure environment as the main line,based on the gasket sealing performance test technology principle,and develops a high temperature sealing gasket performance test device.Carried out theoretical analysis and experimental research on the influence of temperature,pressure,gasket structure and other different conditions on gasket sealing performance.Firstly,using the developed high-temperature sealing gasket performance testing device,the gasket compression resilience performance was tested,and the influence of test temperature,gasket inner and outer ring,and force loading and unloading speed on the gasket compression resilience performance was analyzed.The compression resilience curve is obtained,and the deformation law of the gasket compression and resilience process at high temperature is obtained.Secondly,the leakage rate test of the metal spiral wound gasket under high temperature and pressure environment was carried out,and the influence of test temperature,medium pressure and total load on the leakage rate was analyzed.Using MATLAB to obtain the fitting equations of test temperature,medium pressure and leakage rate respectively,revealing the power exponential relationship between test temperature and leakage rate,and the linear relationship between medium pressure and leakage rate.In addition,combined with the leakage rate under the high temperature test,the gasket coefficient m is corrected,which provides a basis for gasket selection,design and tightness evaluation of the sealing system.Finally,the finite element model of the sealing system was established by ANSYS,and the thermal structure coupling analysis of the flange bolt gasket sealing system was carried out.In order to improve the accuracy of the simulation results,the compression rebound test data was imported into the gasket unit in ANSYS,the heat transfer model of the bolt air layer and the air layer between the upper and lower flanges is deduced and established,and the temperature field distribution law of the entire sealing system is analyzed.The strength of flanges and bolts was checked in accordance with the JB4732 code;the stiffness of the flange was evaluated in accordance with the ASME Ⅷ-1 code;combined with the actual leakage rate,the revised gasket coefficient m is used to reverse the residual compression stress of the gasket to evaluate the gasket sealing,thus,the tightness evaluation of the whole sealing system is completed.