GB418403A - Improvements in or relating to the electrical precipitation of suspended particles from gaseous fluids - Google Patents

Abstract

In an electrical precipitation system comprising a number of treater units connected in parallel to a single source of high tension current, spurious oscillations and surges are minimized by connecting surge-resisting impedances in each of the supply lines to the individual discharge electrodes and also connecting surge-resisting means may comprise a single from the collecting electrodes. The latter surge-resisting means may comprise a single impedance in the common return lead or individual impedances in each lead to a collecting electrode or a combination of both. Suitable impedances include chokes, resistances, thermionic valves or combinations thereof. Fig. 2 shows a typical arrangement in which resistances A are interposed in the parallel leads to each discharge and collecting electrode. Fig. 6 shows an arrangement in which four thermionic valves K are used as rectifiers for each precipitation unit and resistances R are interposed in each lead between the transformer and the point of rectification. The resistances in series with each unit are preferably 100,000 ohms or more, and may be wire-wound, carborundum rods or semi-conducting materials <PICT:0418403/III/1> <PICT:0418403/III/2> <PICT:0418403/III/3> <PICT:0418403/III/4> <PICT:0418403/III/5> <PICT:0418403/III/6> such as Portland cement concrete. The use of semi-conducting materials of this type enables the resistances to be inserted close to the supports of the discharge and collecting electrodes or to be incorporated with the dischargeelectrodes. Fig. 10 shows an arrangement in which the discharge electrodes are suspended from metallic pipes F and connection to a steel beam D carrying the high tension current is made through a block O of high resistance or semi-conducting material. Alternatively the single block O may be dispensed with and individual blocks of such material inserted in each discharge electrode wire. The discharge electrode may also consist of a flat block of semi-conducting material having a central conductor and definite wire discharge points are inserted along the edges. Two examples are shown in Figs. 14 and 14<a> and 15, the former consisting of a block of such material suspended by a metal chain 16 and having discharge points 15, and the latter comprising hollow blocks 11 with arms 12, arranged on a central conductor 10, the arms 12 having discharge points 13. In these cases, the discharge electrodes are preferably arranged with their longer dimension parallel to the flow of gas.