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AssigneeThe United States of America as represented by the Administrator of the U.S. Environmental Protection Agency
InventorsDuane H. Pontius, Wallace B. Smith
Estimating the term…
An apparatus and method for reducing back corona effects while charging high resistivity dust or the like in a corona field, includes a corona discharge electrode, a passive electrode and a screen electrode, the screen electrode being positioned between the discharge electrode and the passive electrode. The screen electrode is positioned more closely to the passive electrode than the discharge electrode and is supplied with an electrical potential which is of the same polarity as and a fraction of the magnitude of the discharge electrode relative to the passive electrode. Gas having entrained therein the particulate material, which is to be removed, flows between the screen and discharge electrode and thence to a particulate material collection stage. The space between the screen and corona discharge electrode remains essentially a unipolar ion field, while ions of the opposite polarity originating at passive electrode due to back corona are collected by the screen electrode.
A method of removing particulate material from gas using a charging stage and a separate electrostatic collecting stage while reducing back corona effects in the charging stage, the method comprising providing in said charging stage an ion field of given polarity between at least one corona discharge electrode and at least one passive electrode in said charging stage, removing ions of opposite polarity which may result from back corona discharge from said at least one passive electrode by capturing the ions of opposite polarity with at least one intermediate, apertured electrode positioned between said at least one corona discharge electrode and said at least one passive electrode, passing gas containing particulate material to be removed substantially longitudinally through the space between said at least one intermediate, apertured electrode and said at least one corona discharge electrode to charge said particulate material while preventing gas containing particulate material from longitudinally entering the space between said at least one passive electrode and said at least one intermediate electrode, and thereafter passing said gas containing said particulate material to be removed out from said charging stage containing said at least one corona discharge electrode, said at least one passive electrode and said at least one intermediate electrode, into said separate electrostatic collecting stage to collect said particulate material in said electrostatic collection stage.
An apparatus for removing particulate material from gas using a charging stage and a separate electrostatic collection stage while reducing back corona effects, the apparatus comprising said charging stage, said charging stage having at least one passive electrode, at least one corona electrode spaced from said at least one passive electrode and at least one apertured intermediate electrode positioned between said at least one corona electrode and said at least one passive electrode for intercepting ions originating from back corona discharge from said at least one passive electrode;
Dependencies are inferred from the claim text.