Seven common types of dynamic seals in mechanical design

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Sealing issues in rotating equipment are a constant concern throughout the operation of such equipment. Today, we have compiled information on the various types of seals commonly used in rotating equipment, along with their applications and characteristics, so that everyone can gain a deeper understanding of these sealing problems. Based on their structural features, packing seals can be classified into: soft packing seals, hard packing seals, and molded packing seals. 1. Soft Packing Seals: Types of soft packing include packers. Packers are typically made by weaving together relatively soft linear materials, and strips with a square cross-section are used to fill the sealing chamber. A gland is used to apply pressure to compress the packing, forcing it against the sealing surfaces (the outer surface of the shaft and the sealing chamber), thereby generating radial forces that create a sealing effect. Applications of soft packing: The material used in the manufacture of packing rings determines their sealing performance. Generally, the material used for such packing rings must take into account the temperature, pressure, and acidity or alkalinity of the working medium. Additionally, factors such as the surface roughness of the mechanical equipment on which the packing rings operate, as well as its eccentricity and linear speed, also influence the choice of material for the packing rings. Graphite packing can withstand high temperatures and pressures, and it is one of the most effective products for solving sealing problems in such extreme conditions. It is corrosion-resistant, has excellent sealing properties, and operates in a stable and reliable manner. Aramid packing is a high-strength organic fiber; the woven packing is then impregnated with polytetrafluoroethylene emulsion and lubricants. PTFE packing is made from pure PTFE dispersion resin; first, a raw material film is produced, and then it is twisted and woven to form the packing. It can be widely used in valves and pumps in industries such as food processing, pharmaceuticals, and paper and textile manufacturing, where high cleanliness standards are required, as well as in environments with highly corrosive media. 2. Rigid packing seal: Rigid packing seals are divided into open-ring and segmented-ring types.