| 摘要 |
<p>PURPOSE:To prevent deterioration of efficiency by equipping both a high voltage generating circuit for impressing high voltage to an electric discharger and a current detecting means for detecting earth current. CONSTITUTION:High voltage is impressed to an electric discharger 16 and atmospheric discharge is performed to the earth bodies 19 from an electric discharge body 18. When the air sucked through a suction port 15 is passed through an electric discharger 16, electric charge is given to dust contained in the air. When dust charged with electric charge is passed through an electrified filter, it is attracted thereon by attracting force of electric charge and only clean air is passed through a fan 13 and discharged through an exhaust port 25. When current allowed to flow to the earth from the earth bodies 19 is gradually lowered according to accumulation of dirt, the current is detected with a current detecting means 22 and when the detected value is made to preset value or below, an output signal is generated. This output signal is sensed with a controlling circuit 23 and necessity for cleaning the electric discharge body 18 is shown. Thereby the period of maintenance is made clear.</p> |
