| 摘要 |
Method in the manufacture of a heat exchanger tube comprising an outer tube 2 and at least one inner tube 1, 4 fitted inside the outer tube and if necessary provided with outer distance pieces. The tubes have a spiral form. The inside diameter of the outer tube 2 is greater than the outside diameter of the inner tube 1 or greater than the sum of the outside diameter of the inner tubes 1 and 4. The outer tube 2 is formed separately into a spiral, and at least one inner tube 1, 4 is formed into a spiral with the same pitch as that of the spiral formed by the outer tube. The outside diameter of the spiral of the inner tube falls within the inner circumference of the outer tube. The spiral formed by the inner tube 4 is then screwed into the spiral formed by the outer tube 2, and is subsequently fastened in sealing arrangements 3 known in the art to the ends of the outer spiral tube 2 and the ends of at least one inner spiral tube 1. <IMAGE>
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