ELECTRICAL DUST PRECIPITATOR

PURPOSE:To improve the dust precipitation efficiency of dusts having high specific electric resistance with simple constitution in a device of generating electric discharge between a discharge electrode and collecting electrodes with a DC voltage, by inverting the polarities of the DC voltage when the discharge current attains a value higher than the set value. CONSTITUTION:When respective movable contacts 3C, 4C of a duplex switch 5 are connected respectively to fixed contacts 3A, 4A, the anode and cathode of a DC electric power source are connected to a discharge electrode 1 and dust collecting electrodes 2, respectively, whereby corona discharge is generated between both electrodes. The dusts in gases flowed in this area are captured on the electrodes 2. When the discharge current between both electrodes increases gradually and the detected value of a device 6 exceeds the set value of a comparator 7, a switch driving device 8 is driven by the output thereof, and connects the contacts 3C, 4C of the switch to fixed contacts 3B, 4B, respectively. The cathode and anode of the DC power source are connected respectively to the electrodes 1, 2 by this, and the electric charges on the surface of the dust layers deposited on the electrodes 2 are neutralized gradually. Thereafter, the similar stages are repeated.