| 摘要 |
PURPOSE:To prevent generation of noise of super low speed air flow surely upon the low air volume operation of the fan by a method wherein a coupling means connecting first runner, fixed to a shaft, and the second runner, supported by the shaft through a bearing, is provided in the fan. CONSTITUTION:The runner driving shaft 7 is provided with the first runner 1, fixed thereto, and the second runners 2, 3, both of which are supported thereby through bearings. The first runner 1 and the second runners 2, 3 are connected through clutch plates 4, 5. When the centrifugal fan 15 is operating under a normal load operation, the whole of the runners 16 are rotated to discharge a necessary air volume to the supplying side. When the air volume, used at the supplying side, is reduced, the connection of the coupling means 17 is released in accordance therewith. Accordingly, the discharging air volume may be decreased in the manner as if the width of the blade for the runners 16 is narrowed. |
