| 摘要 |
<p>An arrangement relating to a drainage pipe (1) having inlet holes (2) for water and a separation wall (3) between an inlet and an outlet section of the pipe, the inlet section of the pipe having an array of said holes (2) in one half of the lower portion of the pipe. A portion of the separation wall has also an array of holes (4), said portion being horizontal or vertical. The drainage pipe can be made from a single folded and joined plate with said holes made in the plate before the pipe forming process. Alternatively the pipe is made through a process of extrusion, said holes being made thereafter by a rectilinear work operation. </p> |
