L Foot Fins

L Foot Fins

L-Foot Tension Wound Finned Tubes are an economical solution for applications requiring greater resistance to vibration and heat cycling typical of air cooled heat exchangers. The L foot design mechanically locks the fins to be the base tube providing broader contact surface between tube and fin.

What is L-foot finned tube?

L-foot finned tube also called Wrap-On Finned Tube or L-type tension wound finned tube, which used in applications where temperatures lower than 300℃. In other words L fin tubes mainly used in low-temperature application where some degree of tube wall protection is needed.

L-Foot tension wound fin tubes consist of two parts, aluminum fin and base tube. The thin aluminum fin strips tightly wound helical around the base tube circumference. A foot is first formed at one side of the fin strip (Called the name L foot). The strip is then wound tightly around the tube, with the foot bearing on the tubes outer surface. These short horizontal limb of each L are in full contact with the base-tube surface to cover it completely. While Tension in the fin strip as it is wrapped around the tubes serves as seat the fin foot forcefully on the tube, and then to hold the fin firmly in place.

L-footed finned tubing offer maximum heat transfer at lower temperatures circumference. The unique L-shaped design holds fins rigidly to withstand heat cycling and high velocity air vibration. These fins offer a certain degree of atmospheric protection of the tube wall anti corrosion. The broad contact surface between the tube and the fining enhances heat transfer. This fin design is highly efficient and cost effective.

The ends of the fins have to be stapled to prohibit the aluminum fin from unravelling or loosing the contact between the fin foot and the base tube. This contact is critical to the operation of the air coolers, since the heat is transferred from the tube wall, through the fin, to the surrounding hot air.

“L” Footed Finned Tubing

L-footed fin tubing is designed to provide uniform fin spacing and prevent separation and movement under cycling conditions within the 450°F range.

The L foot provides a greater surface area for the fin to attach to the tubing, and the shoulder edge helps to interlock the fins. This design helps to improve the heat transfer performance of the tubing and prevent potential damage from cycling.

L-Footed Fin Tubing

“L” Foot or Shoulder tension construction assures uniform fin spacing, rigidly interlocked by the fin radius overlap over the exposed shoulder edge. This prevents separation and movement under cycling conditions within the 450°F range.

L Foot Fins Advantages:

1. Suitable for using in low-temperature application

2. L-foot finned tube is the most cost effective way compared to the others.

3. The failed fins could easily removed during production and bare tubes can be used again for fining.

4. There is no need to make a helical groove over the core tube.

5. L-foot finned tube is possible to place the fins on a super thin-walled tube with is particularly desirable when using expensive alloys as core tubes.

6. The L-foot finned tube can withstand a temperature of up to 130°C without the risk of atmospheric corrosion or thermal stress.

L-Foot Finned Tubes Options:

Double L-Foot Tension Wound Finned Tubes
Perforated L-Foot (Wheel Fin)
Knurled L-Foot Tension Finned Tubes

Knurled L Fin
An interference fit type fin with mechanical knurling of the fin material to the tube wall surface.

Double Overlap Fin
The double LL coverage provides a double strip thickness coverage of the entire base tube.

Perforated L Foot Fin
This enhancement of the fin face creates “tear drop” slits around the helix that break up air flow.

L Foot Fins Application:

1. Oil and gas refineries
2. Petroleum, chemical and petrochemical industries
3. Natural gas treatment
4. Steel making industry
5. Power plants
6. Air conditioning
7. Compressor coolers