GB556939A - Improved method of and apparatus for removing dust or other foreign particles from gas or air - Google Patents

Abstract

556,939. Electrostatic precipitation apparatus. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. April 22, 1942, No. 5383. Convention date, May 13, 1941. [Class 39 (i)] [Also in Group XII] In the removal of particles suspended in gases, the gases are passed first through an electrostatic field which ionizes them and charges the particles and then through a spray of liquid particles oppositely charged to which the suspended particles adhere. The liquid may be water, and may be treated with any desired wetting agent ; it may also function to humidify the gas or otherwise condition it. One form of apparatus is shown in Fig. 1, in which the gas to be cleaned passes through a conduit 2. On the upstream side an ionizing field is established between a thin wire electrode 10, which has preferably a high positive potential, and electrodes 12 of large dimensions which are earthed through the conduit. A spray is produced by an earthed nozzle 15, and is charged negatively in the field between the nozzle and a positively charged ring electrode 20. Baffles 30, and a sharp bend 6 in the conduit separate the liquid particles which are collected in a trap 36. The field behind the electrode 20 may be modified to diminish space charge effects by a series of parallel plates disposed across the line of flow of the gas and preferably connected to the conduit. The apparatus may be duplicated and operate in cascade, the liquid particles carried by the gas stream from one stage being precipitated in an elecrostatic field before the gas passes through the next stage as in Fig. 5 (not shown). If desired, the liquid may be circulated through the spraying device by a pump and filter; and, where the spray is formed by a stream of air, this may be taken from the cleaned gas. In modifications, the spraying means consist of a number of nozzles fed by a header extending transversely across the gas conduit, each coacting with a ring shaped electrode, and the latter may consist of pairs of concentric rings juxtaposed and electrically connected. The spraying means may be duplicated in the direction of the gas flow. The electrode in the ionizing zone may be disposed axially of the conduit instead of transversely, and the apparatus may be arranged for the treatment of downwardly flowing gas, Figs. 6 and 7 (not shown).