| 摘要 |
<p>This method consists in preparing by extrusion an inner plastic tube (100) and in forming around the latter a metallic tube (300) which is covered by an outer plastic layer (900). The metallic tube (300) is formed to an internal diameter substantially greater than the external diameter of the inner plastic tube (100). This metallic tube (300) is closed by welding (40) edge to edge without overlap. The excess in diameter of the metallic tube (300) is reduced without drawing or stretching of the latter. …<??>Adhesive coverings (200, 700) may be interspersed between the various constituent layers or tubes and a braid (800) may be interspersed between the metallic tube (300) and the outer plastic layer (900). …<IMAGE>… </p> |
