| 摘要 |
<p>A centrifugal fan having the inner edges of the impeller blades (7) extending parallel to the impeller axis incorporates a circular damper plate (11) supported coaxially within the array of blades with its edge closely adjacent the inner edges of the blades, and movable in an axial direction so as to vary the useful width of the blades and thereby the flow rate. The damper plate, being separate from the impeller (2), may be supported in a non-rotatable manner and enables the fan to operate at an efficiency comparable with one having a radial vane damper, but is simpler mechanically as it requires only a single primary moving part.</p> |
