| 摘要 |
PROBLEM TO BE SOLVED: To provide a centrifugal fan having no casing, of which airflow characteristics and noise characteristic are prevented from being deteriorated.SOLUTION: An ion generator includes: an outer-surface concavity 14 disposed on the contour surface 13 of a body 1; a metal fitting 12 for fixing the body 1 to the ceiling, with the outer-surface concavity 14 being movable; and an inner-surface inclined part 20 inclined toward the lower part of an inner-surface protrusion 19 formed with the outer-surface concavity 14. Since the wind discharged from a turbo fan 7 flows along the inner surface of the body, downward along the inner-surface inclined part 20, the air flow characteristics and the noise characteristics of the turbo fan 7 having no casing are prevented from being deteriorated by the inner-surface protrusion 19, i.e. protrusion as fitting part of the metal fitting 12 for fixing the body 1. |
