| 摘要 |
PURPOSE:To manufacture a surely joined double-ply pipe by oppositely lapping a precooled reduced-diameter inner pipe with an outer pipe, expanding the inner pipe with a core bar, passing heated increased-diameter outer pipe relatively, and further fitting by cooling. CONSTITUTION:When a double-ply pipe 3' is drawn to the right by operating a driving device 15, and a heating device 10 and a shower device 13 are operated, the inner pipe 2 is mechanically and plastically deformed by a core bar 4 as the position of the die 5 is fixed. On the other hand, the outer pipe 1 increased in diameter by the heating device 10 is restrained mechanically by the die 5 and united with the inner pipe 2 firmly. The diameter is reduced by cold water coming from the shower device 13. Expanding force of the inner pipe 2 is released and pulled backward by being firmly combined with the outer pipe 1. A combined double-ply pipe 3 is obtained by pulling of the double pipe 3'. When city water is removed from the pipe, the temperature of the outer pipe is lowered to atmospheric temperature and the shrinkage of diameter is promoted, and the temperature of the inner pipe 2 is raised to atmospheric temperature increasing the diameter. Thus, firmly combined double-ply pipe is obtained. |
