| 摘要 |
An extractor fan (37) removes air via a first air extraction pipe (38) containing a bottleneck region (26). A second extraction pipe (39) with a wider cross-section removes air from a different part of the building and flows into the first pipe in its bottleneck region. Air is sucked up the second pipe due to the so-called venturi effect due to the underpressure generated by the increase in air velocity in the first pipe caused by the bottleneck region. |
