| 摘要 |
PURPOSE:To prevent the generation of inverse ionization, in a conventional electric dust collecting apparatus due to corona discharge, by providing a means for intermittently applying negative polar voltage. CONSTITUTION:The negative polar voltage from a negative polar power source 2 and the positive polar voltage from a positive polar power source 3 are applied to the discharge electrode of an electric dust collecting apparatus 1 while changed over by a change-over switch 6 and this changing-over timing is controlled by a control apparatus 5 so as to change over said switch 6 when a discharge current detected by a discharge current detector 4 exceeds a predetermined value. At this time, a charging stop timer 9 is provided to the negative polar power source 2 to intermittently output the negative polar voltage and the charging time of the positive polar voltage is made short in the changing-over of the control apparatus 5. By this mechanism, if the inherent electric resistance of dust reaches about 10<13>OMEGA.cm or more, no inverse ionization is generated.
|
