| 摘要 |
1284957 Insulating pipes KABEL-UND METALLWERKE GUTEHOFFNUNGSHUTTE AG 4 June 1970 [7 June 1969] 27016/70 Heading F2P A thermally insulated pipe comprises a layer of foamed synthetic resin between two coaxial tubes, one or both of which is of synthetic resin, wherein a water vapour impermeable foil is provided between the foamed resin and the or each resin tube. The foil is metal, e.g. copper or aluminium, and may be coated on one or both sides with a layer of a thermoplastics polymer, e.g. a copolymer of polyethylene with comonomers, which clings to the foil. The foil has an area of overlap in the axial direction, adhesively bonded or welded. The outer tube is formed from a pre-shaped synthetic resin material strip, the foam forming mixture being simultaneously applied to the foil inside the outer tube as the latter is formed by closing the strip. |
