GB1519542A - Electric dust precipitator - Google Patents

Abstract

1519542 Electrostatic precipitators NIPPONKAI HEAVY INDUSTRIES CO Ltd 8 June 1976 23583/76 Heading B2J [Also in Division G3] In an electrostatic dust precipitator including a number of pairs of dust collecting electrode groups 2 disposed parallel to each other in the gas flow direction, and spaced apart transverse to this direction by more than 400 mm, each collecting electrode 3 comprises a hollow, tubular member through which a temperature controlling fluid is passed. The cross-section of the collecting electrodes may be rectangular or circular, with or without additional cooling fins (81), dumb-bell like or somewhat castellated and formed by opposed grooved plates, Figs. 17AF (not shown). The temperature of the cooling fluid flowing through the collecting electrodes 3, headers 7 and 10 and supply pipe 11 having an expansion bend 12 Fig. 4, is controlled by a system, Fig. 16 (not shown), see Div. G3, in which the spark discharges caused by back ionization in the precipitator are detected and the signal derived therefrom is used to control a valve that adjusts the amount of cooling of the circulating fluid. The groups of collecting electrodes are cleaned by respective scraping assemblies 4 comprising two sliding bars 5 which slide along opposed surfaces of the electrodes and are suspended by pulley-driven chains 6 from points intermediate the ends thereof. The chains 6 are connected to brackets 44 on the sliding bars 5 by drawing plates 46, Fig. 9, in an adjustable manner that allows the pressure between the bars 5 and the electrodes 3 to be varied. The faces of the sliding bars 5 have recesses 43 in which are mounted respective sliding blocks (51), Figs. 11A-C (not shown), which may comprise metal or synthetic resin or the like blocks biassed by a leaf spring or rubber backing, or may be formed entirely of elastomeric material. To assist in moving the sliding bars the pulley system may be provided with a counterweight (31), Figs. 7 and 8 (not shown) which slides within a guide tube disposed within one of the collecting electrodes. Adjacent the top end of the electrodes there may also be provided a further cleaning arrangement 9, Figs. 4 and 5, comprising bars 25 suspended on rods 24 from beams 21, which cleans the back surfaces of the sliding bars 5 when they are raised to the top of the collecting electrodes 3. The various relationships between the temperatives of the gas being cleaned and the cooling fluid, the distance between the collecting electrodes, the amount of cooling water used, the velocity of the ionic wind and the apparent resistivity of the dust are discussed with a view to obtaining optimum precipitation efficiency.