| 摘要 |
<p>A pipe-shaped ventilating device (4) having a collar (11) for mounting in a plastic foil or a similar flexible material, e.g. a water-tight foil, placed on the rafters of a roof construction in order to provide for circulation from the air space (5) under the foil (3) is formed to be mounted by a spiral movement around the edge of an opening shaped in the foil. The collar (11) is provided with an upper wall (12) and a lower wall (13), of which the latter is provided with a slit (14) obliquely directed towards the pipe.</p> |
