초록 ▼

The invention relates to heat-exchanger tubes structured on both inner and outer sides with excellent heat-transfer characteristics, which have recesses on the outside and ribs with specific dimensions on the inside. The structuring tools utilized for the various method modifications are adjusted in

The invention relates to heat-exchanger tubes structured on both inner and outer sides with excellent heat-transfer characteristics, which have recesses on the outside and ribs with specific dimensions on the inside. The structuring tools utilized for the various method modifications are adjusted in such a manner that they are not only able to create aligned, continuous grooves and non-aligned, spaced apart recesses but also secondary structures. The heat-exchanger tubes provided preferably with smooth end sections and smooth intermediate sections are utilized in particular in shell and tube heat-exchangers.

대표청구항 ▼

1. A heat-exchanger tube with smooth end sections and at least one structured section between the end sections, whereby an outside diameter of the structured section is no greater than an outside diameter of the smooth end sections, the structural section having the following characteristics:a) spac

1. A heat-exchanger tube with smooth end sections and at least one structured section between the end sections, whereby an outside diameter of the structured section is no greater than an outside diameter of the smooth end sections, the structural section having the following characteristics:a) spaced-apart recesses having an essentially trapezoidal cross section with a length L of a maximum of 10% of the circumference of the tube inclined on the outside of the tube at a pitch angle with respect to the tube axis; b) the pitch P of the recesses being from 0.25 mm to 2.2 mm, measured perpendicularly with respect to their plane of symmetry; c) the width W of the recesses being W=0.6 P to 0.8 P, measured at half the depth T of the recesses; d) the flank angle .delta. of the recesses being .delta.=7.degree. to 25.degree., measured relative to their plane of symmetry; and e) inner ribs with a height H from 0.15 mm to 0.60 mm extending helically on the inside of the tube at a helix angle E from 10.degree. to 50.degree., measured relative to the tube axis.