| 摘要 |
<p>A method of making a tubular element with transverse ribs for a heat exchanger consists in cutting grooves on a tubular blank (1) so as to form protrusions (3), then the tubular blank (1) is made to rotate and a layer of metal is partly cut on its surface with a cutting instrument (4) and simultaneously bent out so as to form ribs (5) on the tubular blank (1), the cutting edge of the cutting instrument (4) being oriented with an inclination in relation to the axis of the tubular blank (1) and the grooves (2) on the tubular blank (1) being cut along a helical line, whereas the inclination of the cutting edge of the cutting instrument (4) is effected in a direction opposite to the inclination of the helical line of the grooves (2).</p> |
