| 摘要 |
A blower includes: an impeller on which there are arranged axial flow blades 40 mounted at circumferential intervals to an outer peripheral surface of a boss; a case surrounding the impeller; and a bell mouth cylindrically constricted to guide gas into the case, wherein an inner diameter of the bell mouth is smaller than an outer diameter of the impeller. Further, each blade has, in the radial direction, a sweepforward wing portion situated on the boss side and exhibiting a positive advance ratio value, and a sweepback wing potion situated on the outer peripheral side of the blade and exhibiting a negative advance ratio value, with the arc length of each blade increasing from the boss side toward the outer peripheral side. Therefore, it is possible to achieve an improvement in ventilation efficiently, through an increase in static pressure and to achieve a reduction in noise.
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