| 摘要 |
PURPOSE:To make the extruded amount of each material for each layer uniform thereby obviating scatter of the thickness of each layer, by connecting a single motor to screw shafts of extrusion dies for extruding materials for layers for a multi-layered pipe thereby the screw shafts are driven by said single motor. CONSTITUTION:As a driving motor 14 connected via belts 16, 17 to screws 3, 4 to be driven simultaneously, the materials fed from hoppers 5, 6 are equally compressed and subjected to extrusion action by the screws 3, 4, and as the materials for layers are fed equally at an integrating passage 10 from extrusion passages 8, 9, the layers are integrated with the thickness of the two layers less scattered. A resin for the inner layer is charged from a hopper 5, while a resin containing a foaming agent is charged from a hopper 6, so that a two- layered pipe having a resin layer coated with an outer foamed layer that is excellent in heat insulating property, heat resistance, and corrosion resistance can be obtained. |
