Patent GB-183768-A (GB)
Title: Method and device for separating suspended particles from electrically insulating fluids, especially gases
IPC: B03C3/66
Filed: 1921-11-16
Abstract: 183,768. Lodge Fume Co., Ltd., (M÷ller, E.). Nov. 16, 1921. Gases and vapours, electrically precipitating suspended particles from.-Suspended matter, more especially when very finely divided, is precipitated, particularly from gases, by first passing them over discharging electrodes of both polarities, so that the particles agglomerate in consequence of mutual attraction and then treating in the ordinary way by means of discharging electrodes of one polarity and collecting electrodes of opposite polarity. A chamber, preferably of enlarged cross-section, may be arranged between the electrical chambers, to assist or complete flocculation, and may be provided with bames. Direct, single-phase, or polyphase current may be employed in the first electric device. In one arrangement, the first electric treating chamber contains one set of discharge wires 1<1> of one polarity and two sets 1<11> of the other polarity, wires in adjacent rows being staggered. Current is supplied by a transformer, with or without a rectifier, to a resistance 27 from which are taken tappings to the two sets of electrodes and to the earthed casing. Preferably, as shown, the electrodes near the walls have a higher voltage. than the intermediate one, but the earth connection 30 may be made at any point from the connection 28 of the central electrode, to the connection 28<1> of the outer electrodes, or beyond. 1f thin wires are used, it may be necessary to adjust the earth connection so that electrostatic distortion disappears. With tighter or more rigid electrodes, the connections may be adjusted so that agglomeration also occurs between the outer electrodes 1<11> and the casing. The gases pass through the non-electric agglomerating chamber a to the precipitator 100(<2>) having two rows of discharge electrodes 1, 1', of the same polarity, and a collecting electrode 2. Diaphragms 4 with openings restrict the flow of gas from one chamber to another. In a three-phase arrangement, the gas may pass successively through three bipolar charging chambers, alternating with non-electric agglomerating chambers, before entering the precipitator. Each bipolar charging chamber is supplied by an independent secondary of a three-phase transformer, which may have adjustable resistances in two of the primaries and adjustable earth tappings on the secondaries. The electrodes may be differently constructed in the three charging chambers; in one chamber those of one polarity may be conductors covered by insulating material, e.g. strips of metal foil between glass plates. In another three-phase arrangement, three sets of discharge wires connected to the interlinked transformer windings are arranged in a single chamber. They may be symmetrically interspersed. appearing in plan on the sides, diameters, and chords of a hexagon, so that those of like polarity form rows parallel to the gas flow. Additional neutral electrodes may be provided. Rows of electrodes may also be transverse to the gas flow, but the other arrangement is preferred. The current is stabilized by the resistances, or by using a transformer of hedgehog type. Discharge electrodes may be kept clean by washing or bv scrapers or brushes. They are mounted in vertically-removable frames, or, if consisting of lattices or netting, in horizontal frames. The sides of the frames ma act as auxiliary field surfaces preventing abnormal discharges from the end wires. Specifications 17840/12 and 19733/13 are referred to.