| 摘要 |
<p>A low-noise centrifugal fan impeller has a multi-cellular form of construction comprising a multiplicity of individual radial flow channels (5) disposed in a circumferential and longitudinal array with respect to the axis of rotation. This increases the "blade passing frequency" as compared to a conventional impeller and since higher frequencies have lower energy for a given flow output the total amplitude of the noise generated can be reduced. Each channel (5) extends from a respective channel inlet to a respective channel outlet which is offset from the respective inlet in the longitudinal direction of the impeller, and involves an increase in the internal dimension of the respective channel in the direction parallel to the axis of rotation, thus assisting deceleration and compression of the air or other medium being conveyed as it flows through the channels.</p> |
