Selection of gaskets for pressure vessels

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The selection of gaskets for pressure vessels requires taking multiple factors into consideration. The key points are as follows: Consider the operating conditions – operating pressure: at atmospheric pressure, low pressure, or moderate temperatures, non-metallic gaskets such as asbestos rubber sheet gaskets can be used. When the pressure is above 6.4 MPa and the temperature is higher than 350°C, metal gaskets are generally preferred. For operating conditions that fall between the two extremes, semi-metallic gasket combinations can be used, such as wound gaskets. - Operating temperature: In low-temperature environments, gasket materials must be protected from hardening and becoming brittle; for example, rubber gaskets may harden and lose their elasticity at low temperatures, making them unsuitable for use in such conditions. In high-temperature environments, such as above 600°C, metal gaskets or special ceramic fiber gaskets may need to be used. - Working medium: In the presence of corrosive media, a corrosion-resistant gasket material should be selected, such as PTFE gaskets. Asbestos rubber gaskets cannot be used for highly toxic, explosive, highly corrosive, or similar media. Consider the properties of gaskets – sealing performance: In applications that require high sealing performance, such as pressure vessels in the nuclear industry and aerospace sector, metal ring gaskets or metal toothed composite gaskets can be used. For general industrial applications with relatively low sealing requirements, non-metallic flat gaskets may meet the needs. - Rebound elasticity: In environments with frequent fluctuations in temperature and pressure, self-tightening gaskets with good rebound elasticity, such as wound gaskets, are advisable. - Gasket thickness: Thin gaskets are advisable when the sealing surface is well finished and the pressure is not very high. When the internal pressure is high, thicker gaskets should be used. - Gasket width: In applications with high sealing pressures, in order to keep the flange structure compact and ensure that the gasket does not fail, narrower gaskets are generally used. Consider flange factors - Seal face type: Full-flat flanges are generally suitable for non-metallic flat gaskets ； For flanges with uneven surfaces or tenon-and-socket joints, wound gaskets or metal-clad gaskets can be used ； Ring-connected face flanges are usually paired with metal ring gaskets. - Flange material: When metal gaskets are used, their hardness should be 30-40 HB lower than that of the flange sealing surface. Consider other factors – cost-effectiveness: While meeting the usage requirements, try to choose gaskets that are inexpensive, easy to manufacture, and readily available in the market. - Installation and maintenance: For pressure vessels with complex structures and limited space, gaskets that are easy to install and replace should be chosen. For areas that are difficult to access for maintenance, durable gaskets should be used.