| 摘要 |
PURPOSE:To prevent overheating of a motor-operated blower through a simple constitution, by a method wherein a valve body made of a resilient material having airtightness is disposed to a valve chamber, formed in an open air incoming passage, so that the action of a valve is exercised on the inner side of a communicating port. CONSTITUTION:A valve body 20 is located in a valve chamber 17A in an open air flow passage 17. The valve body 20 brings two members 21, deformably formed by a resilient material having airtightness, into contact with each other in a position in the vicinity of the inner side of a communicating port 19 of the valve chamber 17A. When a dust collecting chamber is full of dust, an airflow is decreased due to choking of a filter device, and a difference in pressure between the open air side and the suction side of a motor-operated blower 2 is brought to a given value, a gap is provided at a portion where the members 21 are brought into contact with each other, and the open air flows in the valve chamber 17A through an open air incoming port 18, resulting in prevention of overheating of the motor-operated blower 2. |
