| 摘要 |
This invention concerns a method and an apparatus for making a spirally-woun d tube from a hollow thermoplastic profile (1) having a substantially rectangular cross-section, which method comprises the steps of: winding the thermoplastic profile (1) around a drum (2) and joining adjacent loops together by welding, and smoothing the outer weld joint (13) by means of ext ra heat and a smoothing body resting against the weld joint (13). The invention is characterized in that the thermoplastic profile (1), when fed to the drum (2), comes onto a stationary first section (3) comprising spaced sliding mea ns (5) arranged along the periphery, on which section welding is performed, aft er which an inner weld joint (11) thus formed is arranged to run along a spiral groove (14) running around the stationary first section (3), whereby the inn er weld joint (11), as well as the outer weld joint (13), are treated by using extra heat and a stationary smoothing body (10) resting against it, and that the tube, once both of the welded surfaces (11, 13) have been smoothed, is transferred to a rotary driven drum section (4) causing the tube to rotate a nd generating the winding motion of the thermoplastic profile (1).
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