| 摘要 |
An elongate member is coated with a coating, preferably by coextrusion, and the coated elongate member is wound in a helical manner around a mandrel. The coated elongate member preferably has a square cross-sectional shape so that adjacent portions of the coated elongate member engage one another when the coated elongate member is wound around the mandrel. The coated elongate member is then heated so that the coating on adjacent portions of the coated elongate member fuse together to form an integral strcucture. Another layer of material may be provided on the radially inner or outer wall of the coated elongate member.
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