Although the gasket is inconspicuous, it has a very important role. There are many types of gaskets, different sizes, and different materials, which play different roles. Today, Karek talked about the types of gaskets, and how does the high-temperature gasket play the role of high temperature resistance?
Gaskets are classified into non-metallic, semi-metallic, and metallic gaskets by the materials they are constructed from.
1. Non-metal gasket. Non-metal gaskets are soft, corrosion-resistant, and cheap, but they have poor temperature and pressure resistance. It is mostly used for flange sealing of medium and low pressure vessels or pipes at room temperature and medium temperature. Non-metal gaskets include rubber mats, asbestos mats, asbestos rubber mats, flexible graphite mats, and polytetrafluoroethylene mats.
2. Semi-metal gasket (also known as metal composite gasket). Although non-metallic materials have good softness, compressibility and low bolt load capacity. However, its main determination is that the strength is not high, and the resilience is poor, which is not suitable for high pressure and high temperature occasions. Therefore, the combined metal material has high strength and good resilience. Withstands high temperatures. A gasket having a structure in which the two are combined is formed. This is a semi-metal gasket.
3. Metal gasket. Under severe operating conditions such as high temperature and pressure and frequent load cycles, various metal materials are still the preferred material for gaskets. Commonly used materials include copper, aluminum, low carbon steel, stainless steel, and chrome-nickel alloy steel. In order to reduce the bolt load and ensure a compact structure, in addition to the narrow width of the metal flat gasket, various ring gasket structures with line contact characteristics are the preferred form.
① Flat metal gasket. When used flat, there are two types of wide and narrow shims. Wide gaskets require large pre-tightening forces, which can easily cause deformation of bolt flanges. When the pressure exceeds 1.96MPa, they are rarely used on flanges with smooth surfaces. The narrow gasket is easy to pre-tighten and can be used on pipes with a pressure of 6.27-9. 8MPa.
② Corrugated metal gasket. The thickness of the metal plate of the corrugated metal gasket is generally 0.25 to 0.8 mm. The thickness of the gasket is generally 40% -50% of the wavelength. Suitable for pipelines with smooth sealing surface and pressure of 3.34MPa.
③ Toothed metal pad. Toothed metal gaskets are mostly used for pipes of 6.77-9. 8MPa. The tip distance is about 1.5mm, and the tip and root angles are both 90 degrees. Its sealing performance is better than flat gaskets, and its pressing force is also smaller than flat gaskets.
High temperature resistant gasket material
1. Rock wool board: thermal conductivity of 0.041-0.045, fireproof, flame retardant, high temperature absorption, poor thermal insulation
2. Glass wool: Simple construction and free cutting. Antibacterial and anti-mildew, anti-aging, anti-corrosion, guarantee a healthy environment. Low hygroscopicity and stable physical properties.
3. Expanded polystyrene board (EPS board): Thermal conductivity: 0.037-0.041 Good thermal insulation effect, cheap price and poor strength.
4, extruded polystyrene board (XPS board): thermal conductivity: 0.028-0.03 better insulation effect, high strength, moisture resistance, expensive, the surface needs to be treated during construction.
5. Rubber powder polystyrene particle insulation slurry: thermal conductivity: 0.057-0.06, good flame retardancy, can be recycled, the thermal insulation effect is not ideal, and high requirements for construction
High temperature resistant gasket is a kind of metal gasket, which can not only achieve the effect of ordinary gasket, but also adapt to high temperature environment.