Patent ID: 6631758
Filing Date: 2003-10-14
Classification: B21B,B21C,F28D,F28F

Abstract:
A heat transfer tube having a finned inner surface, which is divided into at least two zones (Z1 to Zm) in peripheral direction, the zones bordering adjacent ones of the zones in a longitudinal direction along the length of the inner surface, whereby individual fins having varying fin height extend at an angle of inclination with respect to a longitudinal axis of the tube, wherein the fins spaced apart in the individual zones (Z1 to Zm) are arranged in any desired periodic sequence of at least two fin heights (H1 to Hn, H1>H2> . . . >Hn), whereby adjacent zones (Z1 to Zm) border one another so that at a transition of two adjacent ones of the zones the fin height changes for at least one of the fins.