GB820294A - Improvements relating to h.t. supply means for electrostatic precipitators - Google Patents

Abstract

820,294. Supply systems for electrostatic precipitators. SIMON-CARVES Ltd. Dec. 5, 1957 [Feb. 7, 1957], No. 4209/57. Class 38 (4). A supply system for an electrostatic precipitator 4 comprises H.T. transformer 1, rectifier 2, and a periodically-operated change-over switch 3 for reversing the polarity of the voltage applied to the discharge electrodes of the precipitator. When the electrode-polarity is changed from negative to positive, a contact 7 on the change-over switch opens, and resistor 6 is connected in the control circuit of a transductor 5, so reducing the output voltage of the transformer. Other means may be used for reducing the voltage at which the electrodes are charged with positive polarity. Two transformer-rectifier sets may be provided, one delivering positive and the other negative voltage to the discharge electrodes of two precipitator chambers. The voltage of each set is adjusted to an optimum value for each polarity, and change-over switches, for allowing supply of the electrodes with either polarity, are operated at desired time intervals, Fig. 2 (not shown). In another arrangement for supplying four-precipitator zones, mechanical rotary rectifiers delivering opposite polarities have their shafts coupled to distributor switches. In this arrangement, each zone is supplied with half-wave current which is reversed at suitable intervals, Fig. 3 (not shown). Full-wave voltage may be supplied for a short period to the discharge electrodes after one or a number of polarity changes.