| 摘要 |
In a process for producing a heat-insulated line pipe, a pipe is continuously provided with one or more spacers. Then a thin-walled strip is formed around this pipe concentrically to the inner pipe, entering longitudinally, to form the open seam tube and the longitudinal edges of the open seam tube are sealed so as to be gas-impermeable, a foamable plastics composition, preferably based on polyurethane or polyisocyanurate, is applied to the strip before the strip edges are sealed, which plastics composition foams to fill the annular space between the inner pipe and the outer pipe after the sealing of the strip edges of the open seam tube. In order to obtain an especially tight, simple-to-produce longitudinal seam, the strip edges overlapping one another are sealed by frictional heat which is applied by means of a wheel rotating at high velocity. |
