| 摘要 |
PURPOSE: A multi-blade fan is provided to minimizes a loss of intake flow rate and to enhance the performance of a blowing fan by controlling a movement flowing backward to a centrifugal multi-blade fan side because a fluid flow path of a bell-mouth is obtained to be enough. CONSTITUTION: A multi-blade fan comprises a case(10) and a centrifugal multi-blade fan(20). The case comprises an air flowing hole and a bell-mouth. The bell-mouth is downwardly extended to the central shaft from a ceiling panel side. The centrifugal multi-blade fan is arranged in the inside of the case and rotated based on the same line with the central shaft of the bell-mouth and guides an air flow. The peripheral surface of the bell-mouth is a curved curvature unit becoming gradually extended toward an outer side. A volume of the peripheral surface of the bell-mouth is 1.2% to 1.6% of a volume of the centrifugal multi-blade fan.
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