| 摘要 |
PURPOSE:To lower the noise emitted from the main casing to the outside by insulation of part of the noise evolved by rotation of an impeller and part of the noise generated in a spiral casing. CONSTITUTION:In a main casing 20, an exhaust blower comprising a motor 27 and an impeller 21 fixed thereto is provided and a space 1 functioning as a passageway for air is formed and a ventilation opening 2 to said space 1 is formed in the underside of the main casing 20. The main casing 20 has a screening part 3 which shuts out part or all of the exhaust blower from a vertical view from under; at one end this screening part 3 forms a right-angled bend 5 and the extended screening part 4 projects into the inside of the main casing 20 and forms an extended-screening panel 6. A layer of sound-absorbing material 7 is attached to the inner side of the extended-screening part 4, that is, the extended-screening panel 6. When the impeller 21 is in action, air is drawn into the main casing 20 through the ventilation opening 2 and, through suction holes 23, 24 in a suction casing 25, 26, into the impeller 21, which pressurizes the air and sends it from the inside (d) of a spiral casing 22 and through an outlet 29 to the outside. |
