Metal-wound gasket is a kind of gasket which is widely used at present. It is the gasket with the best resilience in the semi-metal gasket. It is made of V-shaped or W-shaped thin steel strip and various fillers. High temperature, high pressure and adapt to the conditions of ultra-low temperature or vacuum. By changing the material combination of the gasket, the chemical corrosion of the gasket can be solved by various media. The structural density can be made according to the different locking force requirements. The main body and the accurate positioning, the winding gasket is provided with a metal inner reinforcing ring and an outer positioning ring, and the inner and outer steel rings are used to control the maximum pressing degree, and the surface precision of the flange sealing surface contacting the gasket is not high.
1, non-metallic gasket: non-texture soft, corrosion-resistant, cheap, but poor temperature and pressure resistance. It is mostly used for flange sealing of medium and low pressure vessels or pipes at normal temperature and medium temperature.
Non-metallic gaskets include rubber mats, asbestos mats, asbestos rubber mats, flexible graphite mats, and Teflon mats.
2. Metal gasket: A gasket made of metal such as steel, aluminum, copper, nickel or Monel.
Metal gaskets include: octagonal metal gaskets, elliptical metal gaskets, toothed gaskets, lock washers
3. Semi-metal gasket: A gasket made of metal and non-metal materials.
Semi-metal gaskets include: basic spiral wound gasket, outer loop wound gasket, inner ring wound gasket, inner and outer ring wound gasket.
Flange sealing surface type
Face (RF): The surface is a smooth surface, and it can also be made into a dense waterline. The sealing surface is simple in structure, convenient in processing, and easy to carry out anti-corrosion lining. However, the contact area of the sealing surface gasket is large, and the gasket is easy to be squeezed on both sides when pre-tightening, and it is not easy to be pressed.
Boring surface (TG): The sealing surface is composed of a weir and a groove, and the gasket is placed in the groove and will not be squeezed. The gasket can be narrower, so the bolt force required to compress the gasket is correspondingly small. Even for higher pressures, the bolt size is not too large. Therefore, it is easier to obtain a good sealing effect than the above two sealing faces. The disadvantage of the sealing surface is that the structure and manufacture are complicated, and it is difficult to replace the gasket squeezed in the groove. In addition, the kneading part is easily damaged and should be taken care of during disassembly and transportation. The gutter sealing surface is suitable for flammable, explosive, toxic media and high pressure applications. When the pressure is not large, even if the diameter is large, it is well sealed.
Concave surface (MFM): The sealing surface is composed of a convex surface and a concave surface. The gasket is placed on the concave surface to prevent the gasket from being extruded, so it can be applied to high pressure applications.
Full-plane (FF) and ring connection surface (RJ): Full-plane seal is suitable for low pressure applications (PN≤1.6MPa); ring joint surface is mainly used on neck-welded flange and integral flange, suitable for pressure The range is (6.3 MPa ≤ PN ≤ 25.0 MPa).
Other types of sealing surfaces: For the sealing of high pressure vessels and high pressure pipelines, the sealing surfaces may be tapered or trapezoidal groove sealing surfaces, respectively, with spherical metal gaskets (lens gaskets) and oval or octagonal metal pads. Piece fit. The sealing surface can be used in high pressure applications, but the required dimensional accuracy and surface finish are high and difficult to machine.