| 摘要 |
PURPOSE:To provide the heat insulation pipe which has an easily releasable skin and is not injured during execution obtained by providing a slit extending to the longitudinal direction and having a depth approached to the surface of said pipe as a center from the surface of a heat insulating coating material to said coating material coated on a metal or a plastic pipe. CONSTITUTION:In straightening a coated pipe obtained by coating a coating material 2 such as low foamed polyethylene on a metal or a plastic pipe 1 by passing the same between an upper and a lower straightening rolls 6, 6', the central straightening roll among the lower straightening rolls 6' is replaced with a circular blade 7 and, by rotating said rolls and said blade by a chain, one or plural slits 9 extending to the longitudinal direction of said coated heat insulation pipe 5 and having a depth reached to the vicinity of the surface of the metal or the plastic pipe 1 as a center from the surface of said coating material 2 are provided to obtain the objective heat insulation pipe. In this case, to the outermost layer of the coated heat insulation pipe 5, a sheath material 3 is pref. applied in order to prevent fusion bond of the coating material 2 with other material. |
