| 摘要 |
PCT No. PCT/SE89/00448 Sec. 371 Date Dec. 28, 1990 Sec. 102(e) Date Dec. 28, 1990 PCT Filed Aug. 28, 1989 PCT Pub. No. WO90/02917 PCT Pub. Date Mar. 22, 1990.A tube (10) in a heat exchanger, along which a gas transporting heat travels perpendicular to the longitudinal axis of the tube is provided with surface enlarging elements in the form of pieces of metal (11) having a width (B) substantially equivalent to twice the outer diameter of the tube, and a depth equivalent to approximately half its width. One long side of the piece of metal (11) is provided with a circular recess fitting the tube and extending through an angle of less than 180 DEG , and the long edge of the piece of metal facing away from the tube is provided with three slits (14, 15, 16). One of these slits is located centrally and the other two are placed so that the metal tongues (17) produced are substantially equal in width. The central slit is deeper than the others. |
