| 摘要 |
The metal water drainage gutter (10) has a gutter-shaped lower section (11,12,14), and an upper cover (13) fitted with passage openings (15) cut through by a laser beam. The lower section and the upper cover are in a one-piece structure as a seamless or a welded pipe with a rectangular cross section to form the inner zone (16), with a width (B) and height (H) of 20-300 mm and preferably 20-150 mm. The pipe has a wall thickness of 1.8-8.0 mm.
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