Aluminum Extruded Fin Tubes Widely Used

Aluminum Extruded Fin Tube is widely applied in barley malt, paper mill, timber drying, tobacco, food processing, coal mining, petrochemical, chemical fiber, construction materials, printing and dyeing, as more than 30 industries.

Meantime, they are also complementing for equipment such as air conditioner, drying oven, drying room, air coolers and so on.

Extruded aluminum fin tube is rolled as an integrity with no thermal contact resistance, high intensity, featured in thermal shock and mechanical shock resistance. Heat exchangers assembled with this kind of fin tube (extruded fin type) is much better than the one equipped with string fin tubes or hectically wound fin tubes (L/LL/KL type fin).

Extruded Aluminum Finned Tubes, also known as “Integral Finned Tubes”. Integral finned tubes are manufactured by rolling process on tubes. During finning operation, the inside diameter of the tubes is reduced and helical fins are rolled on the tube wall. The tubes material can be Copper Alloy, Brass Alloys, Copper Nickel Alloy, Titanium Alloy, Stainless Steel, Duplex Stainless Steel etc. The pressure required to extrude fins from the aluminum sleeve creates an excellent “pressure bond” between the two materials.

Copper and aluminum com-posited fin tubes are rolled from a muff copper tube, advantaged in tight link, small thermal resistance, good heat transfer efficiency, small flow loss and strong corrosion resistance. When working in long time under heating and cooling conditions, they are durable and not easy to deform.

The integral extruded fin tubes is smooth on surface and easy to clean. When wet cooling in heating and air conditioning project, it is easy to remove the condensation water on the outer surface of the fin, and it is not easy to dust and scale in the heating and other heat exchange.

Embedded G Fin Tube
Embedded G Fin Tube

The fin strip is wound into a machined groove and securely locked into place by back filling with the base tube.

G fin tube consists of aluminum fin strip that is mechanically embedded into the wall of the tube. The embedding process is controlled by tooling that first plows a groove into the tubes outside diameter, then guides the base of the fin into the groove and finally locks the fin in place by rolling the groove closed on the base of the fin. This ensures that maximum heat transfer is maintained at high tube metal temperature 400°C.

Aluminum L-foot finned tube in production
Aluminum L-foot finned tube in production

Fabrication of L fin tubes

The aluminum fin strip or the copper fin strip is folded into an L shape and spirally wound tightly under the action of tension on the outer surface of the base tube. Tension in the fin strip is wrapped around the tube serves to make the fin foot forcefully on the tube, thus hold the fin firmly in place.

An L-shaped foot, 1/16″ wide, is first formed on one side of the fin strip (hence the name L-Foot). The strip is then wound tightly around the tube, with the foot bearing on the tube outer surface. A typical fin spacing is 10 fins per inch of tube length — this can be varied. Tension in the fin strip as it is wrapped around the tube serves to seat the fin foot forcefully on the tube, and to hold the fin firmly in place.

Extruded Aluminum Finned Tubes Product Range

Integral Low Finned Tubes

  • These have fin height less than or equal to fin pitch.
  • Tube Length: Up to 32 meter.
  • Outside Diameter OD: Between 9.52 mm and 38.10 mm.
  • Tube Wall Thickness WT: 0.58 mm (min) and above.
  • Fins per Inch: 11, 16, 19, 23, 26, 30, 40 and 52 FPI.
  • Available in ferrous and nonferrous materials Copper Alloys, Copper-Nickel alloy, Admiralty Brass Alloy C44300, Aluminum Brass Alloy C68700, Carbon Steel.

Integral Medium High Finned Tubes

  • Fin height more than fin pitch.
  • Tube Length: Up to 32 meter.
  • Outside Diameter: Between 19.05 mm and 31.75 mm.
  • Tube wall thickness: 2.1 mm (min) and above.
  • Fins per Inch: 11, 16 and 19 FPI.
  • Available in ferrous and nonferrous materials.

Low Finned U Bend Tubes

  • Manufactured on in-house finned tube bending facility.
  • Easy to install in the equipment maintaining the circulation ratio.
  • Absorb thermal shocks in heat exchanger.
  • Available in Copper Alloys, Copper-Nickel alloy, Admiralty Brass Alloy C44300, Aluminum Brass Alloy C68700, Carbon Steel, 304 and 304L Stainless Steel ranging from 30R to 710R.

Low finned tubes with internal rib

  • Externally enhanced surface area with integrally helical ribs on the inner side.
  • Improved inside heat transfer coefficient.
  • Available in Copper, Copper Nickel Alloy, Carbon Steel with externally 19, 26 fins per inch and internally 8, 10 Ribs.

Low Finned Tubes Coils

  • Manufactured by coiling the integral finned tube.
  • Improved heat transfer area therefore compact size of heat exchangers.
  • Available in Copper, in coil diameters as per user’s requirement (Min Coil ID 50 mm).

High Finned Tubes

  • High Finned Tubes have extruded fin heights up to 0.625″ (16mm). Single metal and bi-metallic finned tubes are available. Bi-metal finned tubes have a separate alloy liner tube inside the extruded fins. The mono-metal finned tubes have no liner tube with the fins integral with the tube.

Corrugated Tubes

  • Manufactured by corrugation process of indenting plain tube with smooth and uniform spiral projections, which generate turbulence in both outside and inside media.
  • Higher turbulence ensures uniform temperature distribution.
  • No thinning of tube wall during process of corrugation.

Extruded Aluminum Finned Tubes Characteristics

  • Heat transfer per meter of tube on the outside is equal to the heat transfer per meter on the inside.
  • The intermediate un-finned section and un-finned sections at both ends help to slip the integral finned tubes in to the tube-sheets of shell and tube heat exchanger in a manner similar to plain tubes.

Extruded Aluminum Finned Tubes Benefits

  • Combination of lower fin height and more fins per meter maintains the general ratio of 1:1 fin height to fin spacing.
  • Doesn’t require higher tube pitch therefore, doesn’t require shell size higher than shell of bare tube heat exchanger.
  • Improved heat transfer coefficient and rate of heat transfer as compared to conventional finned tube designs.
  • Compact design of heat exchanger having lesser weight and size.
  • Improved tube life.

Extruded Aluminum Finned Tubes Quality Assurance

  • Compliance with quality standards, ASME SB111, SB-359, SA-213, SA-450 and all codes as per ASME /EN/ JS.
  • Customer / Third Party Inspection TPI.
  • Fin dimensions checking by IMTEs and Profile checking on profile projector.
  • Stress Relief Annealing of non-ferrous fin tube on in-house electric conveyor belt furnace.
  • Stress relief annealing of ferrous fin tubes as per specifications provided if required by client at additional cost.
  • 100% tubes tested for leakages by Hydrostatic Test as per standard and customers requirements.
  • Third Party Inspection can be offered from Lloyd’s, BV, TUV, BHEL, NTPC, Intertek, SGS, EIL, IBR etc. as per customer requirement.

Extruded Aluminum Finned Tubes Applications

  • HVAC & Boiler
  • Power Plants
  • Heat Recovery Steam Generators
  • Petrochemical Industries
  • Marine Applications
  • Refrigeration Applications
  • Economizers
  • Oil and Gas Coolers
  • Plumbing and Air Conditioning
  • Condensers and Evaporators
  • Shell and Tube Heat Exchanger
  • Other various Heat exchanger applications

Recommended finned tubes

Expansion joints are used in all kinds of different sectors and in a huge range of different industrial contexts. Essentially, wherever there is a need to control pipework movement expansion joints are required.




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