| 摘要 |
PURPOSE:To aim at increasing the suction area of internal air and at enhancing the suction efficiency of the same, by forming a curved surface in a part of an internal air suction port in an internal and external air change-over box, and by arranging an internal and external air change-over door having a curved section along with the curved surface. CONSTITUTION:A fan 1 driven by a motor 2 is housed in scrolls 3, 4, and converts the atmospheric air introduced through a bellmouth section 5, into air having a necessary air blow characteristic in association with its rotation. Further, an internal and external air change-over box 6 is provided on the bellmouth section 5 on the side opposite to the fan 1, and an internal and external air change-over door 4 is disposed in the box. In the above-mentioned arrangement, the suction surface of an internal air suction port 8 in the internal and external air change-over box 6 is formed such that a part of it has a curved surface toward the box 6 around the bellmouth section 5. Meanwhile, the internal and external air change-over door 7 is formed at its front end with a curved section in order to coincide with the shape of the suction surface of the suction port 8. |
