| 摘要 |
<p>Pipework has a layer of fibrous insulation surrounded by a coaxial tubular envelope and by annular supports near the ends of the insulation. The annular supports may be of rigid cellular material, partic. of expanded glass. The external envelope may be of polyester. The insulation of the joints between the two elements may consist of a layer of fibrous material such as glass fibres and a layer of resin such as polyurethane poured between the two annular supports, the whole being protected by a layer of e.g. polyester resin. The device is for carrying fluids at temps. different from that of the ground in which it is buried.</p> |
