FINNED TUBE

BIMETALLIC EXTRUDED
A core tube, or liner, the outside surface of which has been previously polished and carefully digressed, is fitted into an aluminum primary tube. This tube-in-tube assembly is then fed into the fining machine equipped with three spindles, 120 degrees spaced and each fitted with a gang disc.

Such discs, which are stepped in profile and diameter, will first extrude and shape the fin properly and then shrink-fit the primary tube on its liner. DAMAFIN has developed a high performance bimetallic extruded 11 fins / inch finned tube and a 1 1.2 inch diameter extruded finned tube which combines a large flow area with a long life duration.

G EMBEDDED
The fin consists of an aluminum strip whose foot-edge is both tension-wrapped and embedded into the primary tube wall. This results from the combined action of a set of two discs and a ring spacer arranged at right angels to the primary tube. Operating sequences is are follows:

The first disc (groover ) spins a groove into the tube wall; the ring spacer leads the strip foot-edge into the groove and finally the second disc (back filler ) firmly embeds the strip foot-edge into the groove by "caulking " the groove lip.