| 摘要 |
PURPOSE: A centrifugal air blower is provided to reduce turbulent flow and noise by maintaining flux of fluid flowing in the direction of rotating shaft constant. CONSTITUTION: A centrifugal air blower comprises a suction surface(22) having a bell mouth(26) for sucking a fluid; a bottom surface(21) positioned to be opposed to the suction surface; a scroll case(20) serving as a housing, and which is constituted by a scroll type diaphragms(23) interconnecting the suction surface and the bottom surface; and an impeller(10) installed within the scroll case. The suction surface has a protrusion(30) formed inside the suction surface around the impeller. The protrusion has a sectional surface having a height increasing and then decreasing, centering from the suction surface, along the radial direction of the impeller. The sectional surface of the protrusion is shaped as a semi-circle or semi-ellipse.
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