PURPOSE: To improve exfoliative properties of dust by hammering, by interlocking an impressing voltage between the collecting and discharging electrodes of a precipitator and a hammering of the collecting electrode in controlling the operation.
CONSTITUTION: In an ordinary operation, an electric precipitator 5 is operated by impressing a continuous DC voltage on it. A starting signal 101 is outputted from a hammering timer 6 to a continuous signal generating circuit 7 at a set time before the start of hammering a collecting electrode, and the circuit 7 generate a pulsative intermittent signal which becomes a full voltage in a period TON and zero in a period TOFF. This intermittent signal 200 is added to a thyristor controlling circuit 8 and a thyristor 2 intermittently opens and closes at the time intervals of TOFF and TON respectively corresponding to an off-time and an on-time of the signal 100, thereby an intermittent voltage is impressed between the collecting and the discharging electrodes of the precipitator 5. Thus, during the suspension of operation, the electric charge on the surface of dust layer is released and the reverse ionization is restricted, thereby the lowering of dust collecting efficiency is prevented. Further, a decrease of electric charge improves the exfoliative properties of dust by hammering, and a normal operation is restored after hammering.
MITSUSAKA TOSHIAKI
MATSUBARA SEIJI
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