Heat exchange tube structured on both sides and process for making same

摘要

The tube has smooth ends (1a), a structured area (2) on inside and outside and smooth intermediate areas. The outer diameter of the structured area is not larger than that of the smooth ends or intermediate areas. Lines of depressions (3) with trapezoid cross-sections run on the outside at an angle ( gamma ) of 0 degrees -70 degrees to the tube axis (33). Ribs (5) 0.15-0.6 mm high run inside the tube at an angle ( epsilon ) of 10 degrees -50 degrees to the tube axis. The pitch of the recesses is 0.25-2.2 mm, measured perpendicular to the symmetry surface. The width of the depressions is 0.6-0.8 times the pitch, measured at the half-depth of the depressions. The flank angle of the depressions is 7 degrees -25 degrees , measured against the symmetry surfaces. An Independent claim is included for a method for manufacturing a heat exchanger tube.