The function of the gasket is to prevent the leakage of the sealed medium, and the leakage methods can be divided into interface leakage and penetration leakage. The reason for the formation of interface leakage is usually due to the loosening of the pressing force between the sealing surfaces, the aging, deformation, corrosion, wear or burning of the sealing surface, and mechanical vibration under operating conditions. The penetration and leakage are related to the raw material variety of the gasket, the production method, the properties of the sealed medium, as well as the operating pressure, temperature and other factors.
In theory, it is impossible to achieve complete contact between the sealing surfaces even with sealing gaskets, so that there are no microscopic channels or voids. Although these channels are extremely small, their molecular volume relative to the fluid medium is still It is large enough that it is impossible for the fluid to be completely blocked at the edge of the sealing surface, and there will always be some fluid entering between the sealing contact surfaces, and messy hydrodynamic and thermodynamic processes occur in between. It is generally believed that after the fluid enters the extremely thin and irregular gaps between the sealing surfaces, resistance loss will occur during its movement to dissipate its energy, and a stopped boundary layer will occur on the walls of these gaps, and then make the fine The channel becomes narrower or even completely blocked, so that the fluid entering the sealing surface cannot continue to move, and then the sealing is achieved.
The factors that affect the sealing mainly include the following conditions: the appearance of the sealing surface; the touch width of the sealing surface; the nature of the fluid; the temperature of the fluid; the material of the sealing gasket; the preload applied on the sealing surface; Influence (mainly the vibration of the system, the deformation of the connector, the offset of the installation orientation, etc.). If the seal is to be reliable, it is necessary to carefully consider these factors, and the quality and selection of the gasket is also critical.
