| 摘要 |
PROBLEM TO BE SOLVED: To provide a ventilating fan to which an orifice having a small diameter can be attached without forming any step. SOLUTION: A ventilating fan is constituted in such a way that a flange 2 which is expanded in the radial direction is formed at the indoor-side end of a pipe-like wind channel 1 which communicates the outside of a room with the inside of the room and a flange 2 united with an orifice 4 in one body is formed at the indoor-side opening 3 of the wind channel 1. Then a motor 6 is incorporated in the channel 1 and a propeller type impeller 7 which is rotated in the channel 1 is detachably attached to the rotating shaft of the motor 6 and an opening/closing shutter is supported by a shutter frame attached to the indoor-side side face of the flange 2 formed at the indoor-side opening 3 of the channel 1. A dropping-down step 11 is provided around the indoor-side opening 3 of the flange 2 and a second orifice 21 having a port margin section 22 of such a thickness that can be engaged with the step 11 and a diameter smaller than that of the orifice 4 of the wind channel 1 is detachably attached to the wind channel 1. |
