| 摘要 |
PURPOSE:To simplify the production process and make the length of a pipe, which can be manufactured at one operation, longer by a method wherein a band-like body, to which heat insulating foaming agent is adhered, and a band, which holds an inner tube concentrically with an outer tube, are respectively and helically wound round the inner tube in parallel with the insertion of the inner tube in the outer tube. CONSTITUTION:An inner tube 2 is supported concentrically with a fixed outer tube 1 with rotary feeding rollers 3 and at the same time inserted under rotation in the outer tube 1. Further, in parallel with said insertion, a paper band-like body 4 an inner tube holding band 5 are continuously fed so as to be helically wound round the outer peripheral surface of the inner tube 2. During the feeding process of the paper bend-like body 4, a heat-insulating foaming-stock-liquid is sprayed from a foaming agent spreading nozzle 6 so as to be adhered to the paper band-like body 4. The inner tube holding band 5 is wound together with the paper band-like body 4, to which the foaming stock liquid is adhered, round the outer peripheral surface of the inner tube 2 so as to hold the inner tube 2 concentric with the outer tube 1. When the insertion length of the inner tube 2 into the outer tube 1 reaches a predetermined length, the inserted part of the inner tube 2 is cut off from its uninserted part and heated at heating process in order to expand and solidify the stock liquid. |
