| 摘要 |
1,157,239. Thermally insulated pipes. KABELUND METALLWERKE GUTEHOFFNUNGSHUTTE A.G. 17 Jan., 1968 [17 Jan., 1967], No. 2523/68. Heading F2P. A continuous method of manufacturing a thermally insulated pipe constituted by an inner tube 1 insulated with a plastics material and having an outer sheath, comprises applying a self-foaming plastics material to a foil 2 of metallic or non-metallic material at least partly surrounding the inner tube, forming the foil into a tube co-axially around the inner tube, expanding the plastics material to fill the space between the foil and said inner tube, and applying an outer sheath 7 to the thermally insulated tube. The foil may be made of polyteraphalic ester, or of polycarbonate, alternatively it may consist of a laminated metal foil or, of an aluminium foil laminated with polyvinyl chloride. The self-foaming plastics preferably consists of a polyurethane, and the outer sheath may be formed by an extrusion of polyvinyl chloride or, by a sheath of metal which may be in the form of longitudinally or helically, applied bands. As shown the foamable plastics material is applied, in drop form from a nozzle 4, to the foil 3 at a position before the latter completely surrounds the tube 1 and enters a guide and expansion tube 5 in which the foamable plastics material is expanded. A plastics sheath 7 is applied by means of an extruder 6, the expansion tube being adjusted to a predetermined temperature.
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