| 摘要 |
A flat roof duct designed as a vent (L) or the like has a tubular lower part (2) with a supporting plate (6) associated to a countersupporting plate (12). For particular ease of utilisation, the tubular upper part (1) has a thread (8) below the countersupporting plate (12) carried by the tubular upper part (1) in order to join the latter to a central pipe (3). |
