| 摘要 |
<p>A vacuum cleaner comprises a fan unit having a radial flow impeller (15) and a motor (13) for rotating the impeller (15) to cause an airflow along a flow path of the cleaner. The impeller (15) comprises a plurality of blades (16) extending radially from an axially extending central hollow region (17) having an air inlet at one axial end thereof. The air flow path through the cleaner has a substantially uniform cross-sectional area along a substantial part of its length, and comprises a portion (22) which leads directly to the impeller (15) and has an outlet end directly aligned with the air inlet of the impeller (15). <??>The portion (22) of the airflow path leading to the impeller (15) may extend through an insert (20) mounted inside the fan chamber (19) of a conventional vacuum cleaner. <??>The vacuum cleaner has an increased suction power compared with conventional vacuum cleaners having the same motor power, because the air is communicated directly to the impeller (15) through a duct having a substantially uniform cross-sectional area along a substantial part of its length. <IMAGE></p> |
