| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum cleaner in which the decline of suction force with time is suppressed. SOLUTION: A paper pack 31 is provided on the upstream side of a suction airflow duct 25 which is a junction position of a first airflow duct 39 and a second airflow duct 42 and a third airflow duct 52, and an auxiliary pleated filter 43 is provided in the second airflow duct 42 on the upstream side of the junction position. A fine dust filter 53 having a mesh finer than that of the pleated filter 43 is provided in the third airflow duct 52. A first state of forming a main airflow duct W1 and a sub airflow duct W2 and a second state of forming a filter cleaning airflow duct can be switched. In the first state, when the amount of dust caught in the paper pack 31 in the first airflow duct 39 increases and the resistance of the airflow duct of the first airflow duct 39 is increased, dust is branched from the second airflow duct 42 to the pleated filter 43 together with suction air. In the second state, the pleated filter 43 is back-washed with outdoor air sucked from a first outdoor air take-in port 61 and the amount of ventilation of the second airflow duct 42 is secured. Thus, the decline of the suction force with time is suppressed. COPYRIGHT: (C)2008,JPO&INPIT
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