| 摘要 |
A ventilator comprises: a panel (1) having at least one ventilation opening; at least one shutter (4) movably mounted on the panel, the shutter or shutters in a first position allowing flow of air through the ventilation opening or openings and in a second position closing the opening or openings; means, such as electromagnetic means (15), for holding the shutter or shutters in said first position; means, (13) for holding the shutter or shutters in said second position; means, such as springs (14), for effecting movement of the shutter or shutters from said first position to said second position; and sealing means (5, 6,11,12,13) which when the shutter or shutters are in said second position cooperate with the shutter and the panel to provide a seal extending substantially completely around the ventilation opening or openings. |
