| 摘要 |
PURPOSE:To reduce a noise of the fan in the caption by providing such construction as classifying 2(n+1) sheets of blade into two kinds according to the configuration and setting angle of the blade and arranging the two kinds alternately with mutually equivalent work amount. CONSTITUTION:A peak noise generated at a blade 7 has a frequency 3K1N/60(Hz) (K1: constant peculiar to blade 7, N: number of revolution) and a peak noise generated at a blade 8 has a frequency 3K2N/60(Hz) (K2: constant peculiar to blade 8). Peak noises of blade 7 and blade 8 are generated with different frequencies because of differences between respective confugurations and setting angles of respective blades, and two kinds of peak noise are generated. Since the peak noise is divided into two kinds, the magnitude of the peak noise is reduced in comparison with the conventional one noise. Accordingly, the noise caused by an axial flow fan is to be reduced.
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