| 摘要 |
PURPOSE: A centrifugal fan used in a vacuum cleaner is provided to prevent fluid passing through an impeller from flowing back into a gap formed between a bottom surface of the impeller and a casing. CONSTITUTION: A centrifugal fan includes a casing(110) having a cavity therein. An air suction port and an air exhaust port are formed in the casing(110). An impeller(120) is rotatably mounted at an inner center portion of the casing(110) so as to increase a static pressure and a dynamic energy. A diffuser(130) is installed at an outlet side of the impeller(120) in order to convert a part of a dynamic energy of fluid into static pressure. The casing(110) has a fixing plate(111), and a cover plate(112), which receives the impeller(120) together with the fixing plate(111). A back-flow prevention section(150) is provided to prevent fluid from flowing back. The back-flow prevention section(150) has a recess section and a protrusion formed within a radius range.
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