Electric field directed control of dust in electrostatic precipitators

Abstract

In an electrostatic precipitator, a downwardly directed corona discharge is produced at the entrance to dust collecting hoppers attached at the bottom of the precipitator chamber, the corona discharge being produced by an array of corona discharge points connected to a high voltage source and a grounded electrode grid positioned below the corona points near the hopper entrance either in the hopper or in the chamber.

I claim: .[.1. In an electrostatic precipitator having a housing that defines a flow chamber therein, an inlet opening for conveying a flowing stream of gas carrying dust particles into the chamber, an outlet opening located adjacent a bottom portion of the flow chamber, a dust collector hopper for receiving through a bottom opening in a chamber dust particles removed from the gas, and a plurality of emitting and collecting electrodes extending substantially vertically through the chamber across the path of gas flow, the improvement comprising means for generating a corona discharge disposed below the emitting and collecting electrodes and above the hopper, and a grounded electrode configuration disposed below the corona discharge means, the corona discharge means and electrode configuration providing a corona emission and an electric wind from said means toward the electrode configuration when said means is energized..]. .[.2. The improvement set forth in claim 1 wherein the corona discharge 
     
        means comprises an array of corona discharge points..]. .[.3.  The improvement set forth in claim 1 wherein each corona discharge point is electrically connected to an emitting electrode of the precipitator..]. .[.4. The improvement set forth in claim 3, wherein the emitting electrodes comprise wires suspended from the top portion of the chamber, a weight is attached at the bottom of each emitting electrode, and each of the corona discharge points is a length of wire connected to the bottom of each weight and projecting downwardly therefrom, each wire being pointed 
     
     
        at its lowermost end..]. 5. The improvement set forth in claim .[.4.]. .Iadd.8.Iaddend., wherein the length of wire forming each corona discharge point is about 4 inches long, with a radius of about 0.109 inch, and the point is beveled at about 30° from the wire axis. .[.6. The improvement set forth in claim 1, wherein the electrode configuration is a screen formed of two sets of conductive wires, the wires in each set running generally parallel to each other and generally perpendicular to the wires in the other set..]. .[.7. The improvement set forth in claim 6, wherein the screen is disposed about 6 to 8 inches below the corona discharge means, and the distance between the wires in each set is at least about 2 inches, and the wires in each set have a radius of no 
     
     
        greater than about 0.5 inch..]. .Iadd.8.  In an electrostatic precipitator having a housing that defines a flow chamber therein, an inlet opening for conveying a flowing stream of gas carrying dust particles into the chamber, an outlet opening located adjacent a bottom portion of the flow chamber, a dust collector hopper for receiving through a bottom opening in a chamber dust particles removed from the gas, and a plurality of emitting electrodes including wires suspended from the top portion of the chamber with a weight attached at the bottom of each emitting electrode, and a plurality of collecting electrodes extending substantially vertically through the chamber across the path of gas flow, the improvement comprising: a. means for generating a corona discharge disposed below the emitting and collecting electrodes and above the hopper, said means for generating a corona discharge including a length of wire connected to the bottom of each weight and projecting downwardly therefrom, each wire being pointed at its lowermost end; and   b. a grounded electrode configuration disposed below the corona discharge means, the corona discharge means and electrode configuration providing a corona emission and an electric wind from said means toward the electrode configuration when said means is energized. .Iaddend. .Iadd.9. In an electrostatic precipitator having a housing that defines a flow chamber therein, an inlet opening for conveying a flowing stream of gas carrying dust particles into the chamber, an outlet opening located adjacent a bottom portion of the flow chamber, a dust collector hopper for receiving through a bottom opening in a chamber dust particles removed from the gas, and a plurality of emitting and collecting electrodes extending substantially vertically through the chamber across the path of gas flow, the improvement comprising means for generating a corona discharge disposed below the emitting and collecting electrodes and above the hopper, said means for generating a corona discharge including an array of corona discharge points electrically coupled to a voltage source independent from the emitting electrodes, and a grounded electrode configuration disposed below the corona discharge means, the corona discharge means and electrode configuration providing a corona emission and an electric wind from said means toward the electrode configuration when said means is energized..Iaddend.