Flange seal compared with other gaskets, the price is low, easy to use, but the biggest problem is that: although add rubber gasket materials and some filler, but still can't completely fill the densely packed small pore, existence of trace penetration. So in very pollution medium, even if the pressure and temperature is not high also cannot use. In some of the high temperature oil medium, usually in the use of late, because of the rubber and filler, carbide strength drops, loose material, thus generated within an interface and liner penetration, coking and smoke. Flange seal easily bond, this brought a lot of trouble for rubber seal replacement.

Flange seal state, used in a variety of medium pressure depends on the rate of gasket material strength. Flange material containing water of crystallization and the adsorbed water. When the temperature is 110 ℃, the adsorption of water between the fiber have been precipitation two-thirds, fiber tensile strength is decreased by 10%; When the temperature is 368 ℃, the adsorption of water separating out all fiber tensile strength is decreased by 20%.

Due to the flange seal containing chloride and sulfide, after absorbing water and metal flange forming galvanic corrosion, especially the sulfur content of the flange seal seal several times higher than normal, so should not be used in an oily medium. Liner will appear in the media such as oil, solvent swell phenomenon, but in a certain range, will have little impact on the sealing performance.