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US 4,308,036 AGranted
Filter apparatus and method for collecting fly ash and fine dust
AssigneeEFB Inc.
InventorsKarim Zahedi, Jeffrey C. Alexander
Life of this patent
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AssigneeEFB Inc.
InventorsKarim Zahedi, Jeffrey C. Alexander
Estimating the term…
Fly ash and fine dust in a gas stream from a coal combustor, for example, are efficiently collected in a 2-stage, tubular, granular bed filter. The stages of the filter are arranged one above the other so that the granules may move from the upper stage to the lower stage under the influence of gravity. Larger particulate in the gas stream is first collected by the lower stage, and then the remaining particulate is electrically charged and collected by the upper stage. Both stages are electrified sufficiently to rigidify the granular beds and adhere the particulate to the granules, so that the granules and the collected particulate move downwardly through the filters as a plug. Granules that exit from the lower stage are cleaned and returned to the upper stage. Non-porous granules may be used to prevent fine particulate from becoming embedded in the granules.
Apparatus for removing particulate from a gas stream comprising a pair of foraminous walls separated to define a space for a bed of granules, the walls being oriented so that the granules may move from an upper region of the walls to a lower region of the walls under the influence of gravity, means for supplying granules to the upper region and means for removing granules from the lower region to provide a downwardly moving bed of granules, means for passing a gas stream containing particulate through the walls and the downwardly moving bed of granules, means defining electrodes between which the bed of granules moves and means for applying a high voltage across said electrodes producing an electrical field having a field intensity measured in volts per meter of sufficient magnitude to rigidify the bed and adhere the particulate to the bed granules so that the granules and the collected particulate move continuously downward as a plug.
A method of removing particulate from a gas stream comprising providing a moving bed of granules that moves continuously downward from a first region to a second region between electrodes, supplying granules to the first region, removing granules from the second region, passing a gas stream containing particulate through the moving bed of granules, and applying a high voltage across the electrodes producing an electrical field having a field intensity measured in volts per meter of sufficient magnitude to rigidify the bed and adhere the particulate to the bed granules so that the granules and the collected particulate move continuously as a plug.
Dependencies are inferred from the claim text.