FINNED TUBE

L" (WRAP - ON). The aluminum strip foot section is first formed into an L-shape, then tension- wrapped onto the primary tube. The wound fin base sections are close to each other so as to ensure a continuous cover on the primary tube surface. Finally, the fin strip will be fastened at both ends to prevent losing or unraveling.

KNURLED "L". An aluminum strip is folded to form an L-shape and then wound around the base tube. The feet of the fins are joined together and cover the whole tube surface. The root of the fin is knurled simultaneously with inner tube, thus ensuring a tight contact between the fins and the inner tube. Such a result is achieved on the entire width of the fin root, by means of the knurling discs working interdependently.