| 摘要 |
PURPOSE: To obtain a plastic spiral winding double tube which can be applied to a sewage pipe, etc., laid by a propulsion method and has a light weight, excellent strength and watertightness by arranging a spirally wound inner tube, a smooth outer tube and spiral protrusions for connecting both the tubes at the intermediate between the inner tube and the outer tube. CONSTITUTION: A plastic spiral winding double tube comprises an inner wall (inner tube) 1 formed of a spiral winding, a substantially smooth outer wall (outer tube) 2, and a spiral bandlike wall (spiral protrusions to the inner tube) 3 for connecting both the tubes 1, 2 at the intermediate between the tubes 1 and 2. The concrete structure example of the detail can employ, as shown in an enlarged sectional view of the wall, several molds according to manufacturing means. For example, in a corrugated tube having a bandlike material 4 which has, for example a finned U-shaped section and is spirally lap wound with a hollow part 5, a film 7 is spirally lap wound on an assumed cylindrical surface formed by connecting the outer surface 6 of the part 5 to form a double tube having substantially smooth surface. |
