Extruded Serrated Finned Tube, Bi-metallic Fin

What is extruded serrated finned tube?

Extruded Serrated Finned Tubes are bimetallic tubes whose outer aluminium surface is finned by cold plastic deformation, but the aluminum fin is serrated, which great improve the fin tube heat transfer capacity.

How to fabricate the extruded serrated finned tube?

Insert tube into the aluminum muff tube–>compressing or rolling–>Serrated the fins–>strip peeling–>washing–pressure test–>blast blowing–>packaging.

The serrated fin is made of an outer aluminum tube with a thick wall (muff) that is aligned over an inner base tube. The two tubes are pushed through three arbors with rotating discs that squeeze or extrude the aluminum fins up and out of the muff material in a spiral shape in a single operation. After that serrated the fin in 12 tooth or 24 tooth. As a result, the tubes base is completely connected to the main tube. Furthermore the serrated fins increase the flow area of flue gas and wind tunnel effect are increased, and the pressure difference on both sides of the fin is reduced.

Extruded serrated finned tube size and material:

Extruded serrated finned tube advantages:

1. 100% fin-to-tube bond providing exceptional efficiency and longevity.
2. Excellent corrosion protection on the base tube.
3. Easy to clean with a high-pressure water jet without deforming the fins.
4. As the outer sleeve is continuous No galvanic corrosion between the tube and fins.
5. The bonding of the outer and inner tubes removes the risk of loss of contact with the aluminium due to thermal stress and fins are vibration resistant.
6. Higher heat transfer performance for the life of the unit.
7. Extruded Finned tubes are commonly used in applications with temperature up to 325 °c.
8. Liner tube incased in aluminum for maximum corrosion protection.

The extruded finned tubes are produced by compressing an aluminum tube or sleeve, onto the base tube. The bloom is exposed to very high pressures which essentially “grows” the fins into the final fin profiles. This process manufactures an excellent strong joint with great resistance (fin stiffness) as well as exceptional heat transfer capabilities (longevity, temperature range). The advantage of extruded fin tubes are full protection of bare tube against corrosion and fin has high mechanical strength. Extruded finned tubes provide the most stable performance over time as compared to the other fin types. The fin is rolled from an outer aluminum tube by a process using pressure to create a rolled “pressure bond” between the liner tube and fins. The aluminum fin material completely encloses the tube, except at the ends where a tube coating can be applied.

Extruded serrated finned tube application:

Primarily extruded finned tubes are used in high temperature conditions and corrosive atmospheric conditions, such as operating temperatures less than 300°C or off-shore applications; heat pipes air to air heat exchangers for HVAC applications, air dehumidification in air treatment plants, energy recovery in air exhaust system. This kind of fin design is the least economical as compared to the other fin types; main reason due to the increased amount of aluminum used around 40% also increased labors during the manufacturing. However this increased cost can be compensated if using lower grade parent tube material. Air Cooler,Air preheater,Charge Air Chiller, Condenser,Evaporator, Fluid Cooler, Gas Cooler,Oil Cooler, Radiator, Refrigeration,Steam to Air Heat Exchanger etc.