L, LL and KL fin tubes are the most economical way to add surface area: an aluminium fin with an L-shaped foot is wound under tension onto the base tube.
L type — a single L foot; part of the tube remains bare; clean air, moderate duty, HVAC and dryers.
LL type — the foot overlaps the previous fin, shielding the base tube; specified for corrosive or dusty air.
KL type — the foot is knurled before winding, increasing grip and contact pressure; used for higher vibration, higher temperature and longer tubes.
Base tubes run from 9 mm to 219 mm OD in carbon steel, stainless steel, copper, copper-nickel and alloy steel. Fin materials: aluminium 1060/1100/3003 or copper.
Selection is a balance between air quality, temperature, vibration and cost. If you are unsure which foot style suits your duty, send the operating conditions and we will recommend one before quoting.
Related: L / LL / KL Finned Tube · Extruded Finned Tube Production · Embedded G-Type Fin Production