1. Manufacturing process
Extruded fin tubes: The fins are tightly attached to the base tube through a special extrusion process. During the manufacturing process, the material is subjected to strong extrusion pressure in the mold, and the shape gradually changes and is extruded into a fin shape that matches the mold cavity. After forming, it is assembled with the base tube. During the extrusion molding process, parameters such as extrusion pressure, temperature and speed need to be accurately controlled to ensure the dimensional accuracy and surface quality of the fins.
Wrapped fin tubes: refers to fin tubes that are cold-wound at room temperature. It is a high-quality steel strip or aluminum strip that is directly wound on the steel tube by mechanical force. The processing technology is relatively simple and the material is easy to obtain.
2. Structural characteristics
Extruded fin tubes: The fins are tightly combined with the base tube and have low thermal resistance. For example, in aluminum extruded fin tubes, the base of the fins fits tightly with the outer wall of the tube.
Wrapped fin tube: The steel belt near the base tube has obvious wrinkles. The wrinkle shape allows the steel belt to stand tightly on the base tube by mechanical tension without falling over. In addition, the wrinkled steel belt can also cause the gas outside the tube to produce impact turbulence, which promotes the heat transfer effect. However, due to the limitations of the processing technology, the fin pitch is generally large, ranging from 3.2 to 8mm (the minimum fin pitch of aluminum wrapped fin tube can reach 2.3mm), and the unit heat exchange area is smaller than that of extruded fin tube; the thickness of the fin is generally between 0.2 and 0.5 4.
3. Performance characteristics
Extruded fin tube: It has the characteristics of large heat transfer area, high heat transfer performance, corrosion resistance, wear resistance, etc., which can significantly improve the heat exchange efficiency. It is not easy to deform under long-term cold and hot conditions and has a long working life. For example, aluminum extruded fin tubes have the advantages of high heat transfer performance, high strength, low flow loss, and strong corrosion resistance. In addition, extruded serrated fin tubes also have the advantage of good anti-fouling performance. Their serrated shape allows the fluid to form complex flow states such as vortices during the flow process, which helps prevent impurities in the fluid from depositing on the fin surface, reducing the formation of dirt, reducing maintenance costs, and extending the service life of the equipment.
Wound fin tubes: The contact thermal resistance is large, and the contact thermal resistance is more obvious as the use cycle increases. For example, the aluminum wound fin tube is not rigid enough and is not suitable for working environments with large thermal expansion and contraction. It is usually used in systems with relatively stable working environments.
4. Application scenarios
Extruded fin tubes: Widely used in various industrial fields, especially in occasions requiring efficient heat transfer, such as power, petrochemical, refrigeration, boiler water-cooled walls of thermal power plants, and fan coils of large air conditioners. It can also be used in drying operations in wood, food, paper and other industries to provide uniform hot air and achieve efficient drying.
Wound fin tubes: They are also widely used and are usually used in systems with relatively stable working environments, such as hot water heating or cooling. They should be used with caution in occasions where steam and heat transfer oil are used as heating media.
