| 摘要 |
PROBLEM TO BE SOLVED: To make a sheathed pipe separable, and permit also an inner pipe to be pulled during the pulling period by a pulling machine by providing protrusions for supporting the inner surface of an inner pipe in the inner surface of a sheathed pipe continuously in the longitudinal direction. SOLUTION: An inner pipe 1 and sheathed pipe 2 extruded from mold are placed in contact with each other by protrusions, and 2mm interstices are provided elsewhere. Then, the extruded inner pipe 1 and sheath pipe 2 are sized into a true circle by a sizing device set in the front of a water cooling unit to subsequently be cooled and cured by a cooling device. Next, the sheath pipe 2 is held to be pulled by its outer surface. In this instance, no sliding movement exists between the sheathed pipe 2 and inner pipe 1, so that the inner pipe 2 is held at its outer surface through the pulling force of the pulling machine via the protrusions, thereby pulling also the inner pipe. Each protrusion is formed into an acute cross-sectional configuration, wherein the wall thickness of the sheathed pipe 2 is made, e.g. 1.0mm, the inner pipe 1 is made 1.5mm in its wall thickness, and the protrusions 3 are made 1.2mm in its height. |
