| 摘要 |
PURPOSE:To contrive to improve the productivity of heat insulating tube and at the same time enable to manufacture continuous heat insulating tube by a method wherein water main is concentrically inserted in spirally welded steel tube and rigid urethane foam is filled from a nozzle between the spirally welded steel tube and the water main and expanded. CONSTITUTION:Water main pipe 2 is concentrically inserted in a spirally welded steel tube 1. After the rear end of the water main pipe 2 is capped with a cap 5a, a nozzle 4 to pour rigid urethane foam 3 between the spirally welded steel tube 1 and the water main pipe 2 is inserted from the rear end of the water main 2 into the spirally welded steel tube 1 until the tip of the nozzle abuts against a cap 5. The rigid urethane foam 3 is poured under pressure through the nozzle 4 so as to fill and expand the rigid urethane foam 3 between the spirally welded steel tube 1 and the water main pipe 2 simultaneously with drawing-out of the nozzle in order to completely draw the nozzle 4 out of the spirally welded steel tube 1. |
