Hot Steam Fin Tube Heat Exchanger

Hot steam flows in the tube, and the heat it carries is transferred to the fins through the tube wall, and the fins then emit the heat to the surrounding air, realizing the heat exchange between the hot steam and the air. Due to the presence of fins, the heat transfer area is greatly increased, which enables the heat to be transferred more quickly and fully and improves the heat exchange efficiency.

Fin and base tube assembly process

Fin prefabrication: fins are usually round sheet (or square, suitable for rectangular tube bundle), the center of the punched out with the base tube diameter to match the holes (hole diameter is slightly larger than the base tube OD, easy to wear sets), the material is mostly aluminum, copper, carbon steel or stainless steel (according to the corrosive properties and heat transfer needs to choose).

Threading operation: multiple fins are threaded sequentially outside the base tube to form a dense fin group (fin spacing is usually 2-10mm, the smaller the spacing, the larger the heat transfer area, but also the higher the resistance).

Fixed reinforcement: After wearing the fins, it is necessary to eliminate the gap between the fins and the base tube by expanding or welding:

Expansion: Mechanical expansion head (such as hydraulic expander) is inserted into the base tube to expand the base tube diameter-wise, which is tightly fitted with the inner holes of the fins and relies on the interference fit to be fixed without additional weld joints, which is suitable for low and medium-temperature steam (e.g. air conditioning system, temperature ≤150℃).

Welding: If the steam temperature is high (e.g. ≥200℃), the expansion tube may be loosened due to thermal expansion and contraction, and it is necessary to weld (e.g. argon arc welding) at the contact point between the fins and the base tube, to ensure the bonding strength and to reduce the contact thermal resistance.