| 摘要 |
A ventilation arrangement for a building with an air duct extending from roof level, has air openings extending around a housing 10 at an upper end of the air duct, the openings having louvres 12 with passages 14 one above the other, the passages 14 extending upwardly inwards to prevent rain ingress and an upper surface 26 of the passage being concavely curved to urge air to turn downwardly. The housing 10 can receive air on a windward side and expel air on a leeward side. Some louvres 16 are static, while others 18 are movable by interconnecting linkage bars (34, fig 4) to close the passages 14 (fig 3). A slot 32 of the movable louvres 18 engages a flange 20 or the static louvres 16. |
