| 摘要 |
PURPOSE:To manufacture a heat insulation pipe more effective and economically, by a method wherein foamed material is covered on the outer periphery of an original pipe, and the surface of a foamed heat insulation layer is heated and melted, and the skin of the foamed heat insulation layer is made to fine organization. CONSTITUTION:The original pipe P is pushed to an arrow direction by a feeding machine from one end of the side provided with a dice 1, and besides foamed material A1 is pushed out from the dice 1. The foamed material A1 is expanded after passing through the dice 1, and is guided by a long land dice 3, and is covered on the outer periphery of the original pipe P. A foamed heat insulation layer A2 is formed by this process. The foamed heat insulation layer A2 is heated by a heater 4 over the melting point of the foamed material while it passes through a foregoing part of the long land dice 3, and its surface is melted. On the surface of the foamed heat insulation layer A2 which is melted by that process, the organization of it is made fine, bubbles on the surface being distinguished. Hereby, a strong skin layer (a) is formed on the surface. |
