| 摘要 |
1,160,013. Insulated pipes. KABELUND METALLWERKE GUTEHOFFNUNGSHUTTE A.G. 2 May, 1967 [1 June, 1966], No. 20277/67. Heading F2P. A thermally-insulated pipe comprises a copper inner corrugated tube 1, a coaxially spaced steel or copper outer corrugated tube 2, a foamed plastics insulating layer 5 substantially filling the space between the tubes, and a protective layer 6, 7 around the outer tube. The corrugated tubes may be made from spirally or longitudinally welded strip and spaced by a spiral 3. The foamed plastics is preferably polyurethane and may entirely fill the space between the tubes or be applied as webs wound between the spiral when the latter is provided. The protective layer consists of a bitumen composition layer 6 and a sheath of polyvinyl chloride with the optional provision of a foil therebetween. |
