| 摘要 |
<p>An axial air movement fan suitable for a ventilation duct comprises a first, inner array of blades 2 which are contained within an encircling peripheral ring 3 and which define a section of a duct, and a second, outer array of blades 4 extending from the ring 3. The blades 2, 4 are oppositely disposed so that air is moved in one direction by the first set of blades 2 and is moved in a second, opposite direction by the second set of blades 4. The ring 3 may form part of the ventilation duct. A second ring may encircle the second array of blades 4. The fan may be driven by an electric motor. Alternatively, the fan may be driven by wind power, which may be provided by a wind-driven device 6 which rotates the fan in the required direction independent of wind direction. This device may comprise two oppositely-disposed wind bowls 18 projected radially from a vertical shaft 20 extending from the fan hub 1.</p> |
