| 摘要 |
<p>PURPOSE: To provide a dual wall tube, in which inserting and receiving ports are surely connected together and a connected part is provided with proper bendability. CONSTITUTION: In a dual wall tube 1 composed of an outer wall 3 having an annular higher part 3a and a lower part 3b alternately in an axial direction and a flat inner wall 2 welded to the outer wall 3 by heat in the inner surface of the lower part 3b of the outer wall 3, an inserting port 4 is provided in one end, a receiving port 5 is provided in the other end and the end part of the outer wall 3 is formed flat so as to laminate the outer wall 3 and the inner wall 2 in the inserting port 4. On the other hand, the receiving port 5 is expanded in a diameter direction such that the inner wall 2 is tightly fixed along the inner surface of the outer wall 3 and the inner diameter of the lower part 2b of the inner wall 2 is almost the same as the outer diameter of the inserting port 4.</p> |
