| 摘要 |
PURPOSE:To abate the increment of ventilating resistance and noise due to a resistor while securing coolability of this resistor by constituting a heating unit of the resistor for regulating air quantity of an air blower, to be capable of rising or setting from or to a ventilation flue according to the voltage control operation. CONSTITUTION:An air blower 2 is set up in an upstream end of a ventilation flue 1. And, this air blower 2 is constituted of an impeller 2a and an electric motor 2b for driving this impeller. In addition, a battery 6, a fan speed selector switch 7 and a resistor 8 are connected to the motor 2b in series. Likewise, plural heating parts electrically connected, that is, respective resistors 8a are installed in the resistor 8, and these resistors 8a are set up in a recess of a scroll casing 9. At this time, each resistor 8a is formed with a shape memory alloy, whereby these resistors 8a are extended to the ventilation flue 1 by a form variation at the time of heating transformation, thereby cooling them by an air current. |
