Study On The Performance Of Spiral Wound Gasket Based On Leak Rate

From the current pressure vessel design specifications,it is impossible to achieve a quantitative leak rate controlled by the gasket pressure given by the flange gasket design method,the study based on the tightness of the gasket pressure and the corresponding gasket performance under the pressure is essential.This issue is based on to achieve a quantitative leak rate controlled by study the structure and properties about flexible graphite gasket which is commonly used in the typical conditions of service of pressure equipment.The main contents and conclusions are as follows:（1）The experimental study found that compression and rebound performance of the same material density wound gasket is substantially the same;different densities wound gasket,with the winding density increases,gasket compression ratio decreases,spring rate increases.Gasket material 304 respect to the gasket 316,the compression ratio is small,the higher spring rate.High density and harder material is recommend for a higher level of nominal conditions（2）By winding density for different gasket compression elasticity curve fitting,the winding density of such aspects into the mechanical properties of the law of the gasket,comprising winding density obtained gasket compression and rebound characteristics of the characteristic equation equation.（3）The experimental study was repeated loading and unloading process gasket,we found the bolt tightening by step will not cause a greater impact on the mechanical properties of the gasket.（4）It is found that the high-density wound gasket is more suitable,when at lower gasket preload pressure,for sealing at high pressure engineering through the sealing performance tests.It suggests that（18,120）is the gasket coefficient corresponding to 1.2×10^-5ml/s under the 4MPa internal pressure.（5）Through finite element calculation results of the structural integrity of bolted flange joints were analyzed and found that stress on the gasket distributed unevenly,minimal stress on the inside of the gasket,the maximum stress in the outer gasket;the internal pressure will be on the force of impact pads,gaskets uninstall,a corresponding reduction in stress.Spacer radial stress with increasing preload increases,the impact bolt preload minimum stress on the gasket is showing a gradual weakening trend.Through the analysis of the Von-Mises stress distribution on the bolt flange,it is found that the flange has a certain area of yield in the position of the bolt hole.