Patent ID: 6224653
Filing Date: 2001-05-01
Classification: B01D,Y10S

Abstract:
In combination with an electrical apparatus for removing noxious substances from a stream of fluid, the apparatus having an electrical precipitator including a reaction chamber through which a stream of fluid passes and a corona-producing electrode extending into the reaction chamber, a power supply including a frequency converter for converting three-phase alternating current line voltage having a frequency of the order of 50-60 Hz to single-phase voltage having a frequency of the order of 400 Hz, a transformer for raising the level of the voltage from the frequency converter to the order of 30-100 kV, and a rectifier for producing a rectified voltage output in response to an alternating current input; a multi-stage Fitch generator connected to said power supply and including a plurality of capacitive power storage units to be charged to a predetermined constant direct current voltage by the rectified voltage output of said power supply, said Fitch generator further including a trigger circuit connected to the power storage units, the trigger circuit including first switching means for causing the power storage units to produce a pulsating voltage and circuit means for causing rapid extinction of the first switching means discharge; circuitry connecting the output of the frequency converter to the trigger circuit, said connecting circuitry including a phase shifting network for causing the first switching means to be actuated only when the output of the frequency converter is at a minimum amplitude level; and circuit means connected to the power storage units for introducing the pulsating voltage to the corona-producing electrode;a source of inert gas, which may include the aforementioned stream of fluid, connected to the reaction chamber;a valve for controlling the admission of inert gas from said source into the reaction chamber;a source of air, which may include the aforementioned stream of fluid, connected to the reaction chamber; anda valve for controlling the admission of air from said source into the reaction chamber thereby producing an atmosphere containing a predetermined mixture of inert gas and air within the reaction chamber, the mixture providing a concentration of electronically excited metastatic inert gas atoms effective to ionize the noxious substance in the stream of fluid in the reaction chamber.