Patent ID: 6722420
Filing Date: 2004-04-20
Classification: B21B,B21C,F28D,F28F

Abstract:
A heat transfer tube having a finned inner surface, which is divided into at least two groups (G1 to Gp) of zones (Z1 to Zm) in peripheral direction, whereby each group includes at least two zones, and the angle of inclination of the fins in the zones of one group is uniform, however, the angle of inclination varies between the adjacent groups such that when counting starting with one group G1 in groups with an uneven number a different angle of inclination of the fins exists than the angle of inclination in groups with an even number, wherein the fins in the individual zones (Z1 to Zm) are arranged in any desired periodic combination and sequence of at least two fin heights (H1 to Hn, H1>H2>. . . >Hn), wherein adjacent zones (Z1 to Zm) of one group border one another so that at the transition of the two adjacent ones of the zones of one group the fin height changes for at least one of the fins in a longitudinal direction of the tube.