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Def» 17, 1946. w. M. SCHMIDT ET AL 2,412,912 COLLECTING ELECTRODE STRUCTURÉ Filed sept. 25. 1944 3 Sheets-Sheet 2 J 4 y/////////////f` 3/ J2? 3 , 2 ,Dec- 17, 1946. w. M. scHM‘IDT ET A1. . 2,412,912 COLLECTING ELECTRODE STRUCTURE Filed Sept. 25, 1944 ' I ~ "- oaf Fg. 6. ' 0?, 5 Sheets-Sheet 3 Patented Dec. 17, 1946 2,412,912 UNITED STATES PATENT OFFICE 2,412,912 COLLECTING ELECTEODE STRUCTURE Walter Malcolm Schmidt and Donald K. Town-` send, Los Angeles, Calif., assignors to Western Precipitation` Corporation,` Los Angeles, Calif., ‘ a corporation of California ~ l ‘ Application September 23, 1944, Serial No. 555,490 5 Claims. (Cl. 183-7)l . 2 This invention relates to collecting electrodes tions, as shown for example in United States pat of electrical precipitation apparatus for use in ent of Anderson, No.Y 2,192,172, issued March 5, the separation of suspended material from gases, 1940. ‘ ` and’ particularly to collecting electrodes of the Electrical precipitat‘ors of the types above de type in which a thin film of liquid is passed, pref 5 scribed are well known in the art. The present erably continuously, over the collecting electrode invention is concerned only with an advantageous surfaces on which the material is precipitated. form of collecting electrode structure for use in Although the principles of the invention are any type of precipitator employing vertical liquid' applicable to any type of liquid-ñushed collecting fiushed collecting electrodes, and it` will be under electrode, the advantages of the invention will be stood that such electrode structures may be used more particularly described in connection with in connection with any'type or form of opposing liquid-flushed collecting electrodes comprising precipitating electrode. vertical pipes or tubes. Such collecting electrodes are ordinarily assembled within a housing and mounted adjacent their-*upper ends on a horizon tally extending wall or header plate. The gas is passed vertically through the collecting electrode pipes, and an opposing precipitating electrode ex tends centrally within each pipe. Water or other suitable liquid is supplied to the space aroundthe upper ends of the collecting electrodes above the headerplate, and iiows over the upper edges of these electrodes and down the inside surfaces In the treatment of largev volumes of gas, it is customary to provide a considerable »numberv of collecting electrode pipes in a single unitl or sec tion of the precipitator, and it is desirable to maintain a substantially uniform flow of liquid "Lio down the inner surfaces of al1 the pipes. Al though the liquid reservoir above the header plate may be subdivided by partitions into a number of separate compartments, the arrangement is gen erally suchA that each suchV compartment sur rounds and supplies liquid to- a plurality of the thereof, on which the material is precipitated..-`V` electrodes. It is therefore advantageous to pro The space above the header plate constitutes a "25 vide for adjusting the4 upper edges of the indi liquid supply chamber or reservoir, and the upper vidual electrodes», over which the liquid flows. ends of the collecting electrodes extend upward The means for this' purpose- should preferably be ly above the header plate and act as overflow lips such as to provide' not only for Vvertical adjust-g- or weirs to control the ilow of Water into each electrode. An electrical precipitator of this general type is shown 'in United States patent of Crowder et al. ment of the overflow lip or weir atthe upper end 30 of each electrode in order to maintain substan tially equal flow of liquid from the surrounding space into the several electrodes, but also for ver tical angular adjustment of such overflow lip or iiushed pipe collecting electrodes are useful in l weir in order to secure substantially uniform iiow precipitators of the single-stage type, as disclosed ci of liquid at different positions around the circum in the above-mentioned patent, in which the pre ference of each electrode and thus insure substan cipitating electrodes within the pipes are dis tially uniform iiow of liquid over all portions of charging electrodes such as small diameter wires, the collecting electrode surface. or rods provided with sharp edges or points, The collecting electrode pipes are generally of whereby a corona discharge is maintained for the 'llo substantially uniform diameter throughout the purpose of both charging and precipitating sus major portion of their height to provide the de pended particles in the electric ñeld between sired spacing of the collecting surface, and the No. 1,968,334, issued Ju1y 31, 1934. Such liquid these electrodes and the collecting electrodes. Similar liquid-flushed collecting electrodes are ,. also useful in electrical precipitators of the two stage type, in which the charging and precipitat ing of the suspended material are carried out in successive spatially separated fields. In this case the precipitating electrodes within the pipes may comprise non-discharging electrode members of extended surface, such as smooth rods or pipes of sufficient diameter to substantially avoid corona discharge; or the precipitating electrodes may liquid film thereon, from the opposing electrode. It' is desirable that this portion of the collecting electrode surface be free from sharp edges or other irregularities or discontinuities that would. tend to disturb the smooth flow of the liquid ñlm or to cause electrical discharge from the collect ing electrode. Itis also desirable that the upper end portion of the collecting electrode including the overflow lip or> Weir at which the liquid film is formed, as well as the lower end portion of the collecting electrode where the liquid leaves the Collecting Surface, be of materially greater diame comprise composite electrode elements provided with both discharging and non-discharging `por 55 ter than the major portion of the pipe, so as to 2,412,912 3 4 . Fig. 1 is a partial vertical section of an elec prevent electric discharge from the ends of the trical precipitator with several collecting elec collecting electrode and to provide for forming trodes embodying the principles of the invention and breaking the liquid film at positions of re and associated precipitating electrodes shown in duced electric field strength. . It has been found, however, that in spiteof the UI elevation; Fig. 2 is a horizontal section on line 2-2 of most careful vertical and angular adjustment of Fig. 1; the upper end portions of the collecting elec Fig. 3 is an’enlarged vertical section of the trodes in .precipitators of the types described upper end of one of the collecting electrode struc above, inequalities of flow between different col lecting electrodes and at different points of the ` circumference of the individual electrodes are dif ficult to eliminate. Such inequalities of flow are tures of Fig. 1; ' . ' . Fig. 3a is a fragmentary detail of the collecting electrode structure of Fig. 3; Fig. 4 is a vertical section of the upper end particularly apt to arise after the precipitators of a modified embodiment of the collecting elec are put into operation, due to slight variations in rate of supply of fiushing liquid, arising, forA ]5 trode structure of the invention; Fig. 5 is a partial plan view of the collecting example, from partial plugging of feed lines, or electrode structure of Fig. 4; to small shifts due to settling. Fig. 6 is a vertical section of the upper end of We have now found that the adjustment of the level of the upper ends of the collecting elec trodes can be rendered far less critical and sub stantial equality of flow'to the individual col lecting electrodes and about the circumference -thereof can be maintained in spite of consider a further embodiment of the collecting electrode structure of the invention; Fig. 'l is a partial plan view of the collecting electrode structure of Fig. 6; ì Fig. 8 is a fragmentary diagrammatic plan view of the top of the collecting electrode structure of _able variations in the supply of flushing liquid, shifts in level of the apparatus and other chang 25 an electrical precipitator including vertical plate collecting electrodes embodying the principles of ing conditions of operation, by providing a sub stantial hydraulic head of flushing liquid adja the invention; , Fig. 9 is a fragmentary vertical section of the `cent the upper ends of the collecting electrodes, upper portion of the collecting electrode struc and particularly by providing a throttling curtain adjacent the Weir lip at the upper ends of the 30 ture of Fig. 8; Fig. 10 is an enlarged fragmentary detailiin collecting electrodes whereby a controlled flow of vertical section, and Fig. 11 is an enlarged frag liquid to the Weir lip is maintained under a sub mentary detail in plan of the embodiment of Fig. 8; vide a collecting electrode structure which can 35 Fig. 12 is a diagrammatic plan view of the top stantial hydraulic head. A principal object of this invention is to pro be easily adjusted to provide equal flow of flush of the collecting electrode structure of an elec trical precipitator including rectangular vertical ing lliquid over the entire collecting surface of gas treating ducts embodying the invention; and ` `each of the collecting electrodes of a group. Fig. 13 is an enlarged fragmentary detail in v A further object of the invention is the provi sion of a collecting electrode structure which will 4° vertical section on une ls-Ia of Fig. 12. In Figs. l and 2, a plurality of tubular collect maintain an equal flow of liquid over the entire ing electrodes I are shown as extending vertically collecting surface of each of the collecting elec through and supported upon a header plate 2, trodes of a group in spite of substantial changes vin liquid supply, level, or other operating condi it being understood that these electrodes are or dinarily mounted within an enclosed precipitator housing provided with gas inlet and gas outlet ` Another object of the invention is to provide means at opposite sides of the header plate so a collecting electrode structure which will main as to provide for passage of gas to be treated tain a controlled constant rate of iiow of liquid vertically through the several electrodes, as is to the upper end of the collecting electrode under more fully shown and described in the above a substantial hydraulic head. These and other objects and advantages which mentioned United States Patent No. 1,968,334. Each collecting electrode comprises a pipe 3 will be apparent from the further description of of suitable length and diameter, which is of sub the invention are attained by the collecting elec stantially uniform diameter throughout the trode structure of the invention which broadly comprises a vertically-extending electrode mem 55 major portion of its length. 'The upper end of tions. ` - ber providing a collecting surface of extended the pipe extends above the header plate 2, and area, the upper end portion of the electrode car rying a Weir substantially coextensive With the upper end thereof, and a throttling curtain ad is ñared outwardly as shown at 4 to provide an upper edge 5 of materially greater inside diameter than the major portion of the pipe. At the up jacent the Weir, the throttling curtain extending 60 per edge the external surface of the pipe is pref erably finished so as to provide a short cylindri-l a substantial distance above the Weir and being cal bearing surface 6, as shown more particularly spaced therefrom to provide a constricted passage in Fig. 3. to the Weir from a body of liquid adjacent the Each of the collecting electrodepipes extends throttling curtain. Preferably the throttling cur tain is formed to provide a plurality of constrict 55 through an opening 8 in header plate 2 and is shown as supported on said header plate by ed passages substantially equally spaced along the means of an outwardly projecting annular flange Weir. 9 Welded or otherwise secured to the pipe and The weir may be an integral part of the upper supported on the header plate. A suitableV gas end of the collecting electrode or it may be ad justably carried thereby either as a separate 70 ket Ill is preferably provided between ñange 9 and header plate 2 and the ñange is shownl as: member or Vas an element of the throttling cur secured to the header plate by means of bolts> tain. il, thus providing a fluid-tight connection be The invention will be more particularly de tween the header plate and each pipe. scribed With reference to the accompanying draw 75 An adjustable Weir ring I2 is mounted in po ings, in which: 2,412,912 sition around the‘upper end of each pipe 3, With its cylindrical inner surface in close sliding en sagement with cylindrical face 6 on the pipe. Ring I2 extends upward above the upper edge 5 of the pipe and is provided with a plane upper edge I3. Means are provided for supporting and `lecting electrodes to cause corona discharge» from discharge electrodes> 3 I. After the apparatus is erected, but preferably before the throttling rings 2| are installed, a suitable liquid is supplied to each of the com partments deñned by walls 24, and the weir rings adjusting the Weir ring, comprising for example I2 of the several collecting electrodes in each four adjusting screws or bolts i5, extending of such compartments are adjusted as described through outwardly projecting members such as lugs I 6 at equally spaced positions around the 10 4above to provide substantially equal flow »of liquid into the respective electrodes and substantially ring and provided with heads I'I and nuts I8 equal flow of liquid at all circumferential posi~ bearing against the upper and lower faces, re tions around the upper edge of each of the weir spectively, of said lugs. The lower` ends of ad rings. ‘ justing screws I5 engage nuts or other internally 'Iînerear‘ter the throttling rings 2i are put in threaded members I 9' welded or otherwise se» place and the liquid level is raised above the cured to flange `9. Thus, by suitable manipula tion oi’ screws I 5 and nuts i8 the weir ring I2 may be raised or lowered at the position of each adjusting screw, so as to provide vertical ad justment of the weir ring relative to pipe 3 and also for vertical angular adjustment of said ring relative to said pipe. Although the ring ñts quite closely about the external face ö at the upper end of the pipe in order to provide a sub level of the Weir lip to provide a substantial hy :aulic head at the level of the weir lip. This head, together with the throttling action of con stricted flow passages 23, results in the damping out of the effects of fluctuations of level the liquid supply compartments and eliminates or greatly reduces the eifect of small changes in level of the apparatus, thereby maintaining a stantially liquid-tight engagement, the relation- 'i substantialiy uniform downward iiow of liquid through` all the electrodes in a thin ñlm dis tributed substantially uniformly over the entire duly limit such tilting. movement, and the ñt at " this point need not be extremely close in order to substantially prevent leakage of liquid be tween the pipe and the ring. Surrounding the upper ends of the weir rings I2 are corrugated throttling rings ZI which may be-formed by fastening a suitable strip of cor suitable material by rivets inner surface of each electrode. The liquid ñlm is formed- at the upper edge of the weir ring at a position spaced from the opposing precipitating electrode 3l by a distance materially greater than the spacing between the precipitating electrode and the major portion of the inner surface of the- collecting electrode, so as to avoid electrical disturbances. The en tire surface over which the liquid ñows between the top and bottom edges of each collecting elec trode is preferably free from sharp edges or surface discontinuities' or irregularities that y might tend to disturb the smooth flow of' the 40 liquid or to cause electrical disturbances. Although the precipitating electrodes are in this case shown as discharge electrodes. it will of the Weir. 'I‘he depth of the corrugations may be understood that the collecting electrode struc advantageously be of the order of it; inch. ture of this invention may also be employed with The space above the header plate 2 ‘ non~discl1arging precipitating brought out hereinabove. ' ‘ and this space may be di electrodes as In embodiment of the invention shown in Figs. »i and 5, the Weir is provided by the upper edge 5 or" the flared upper portion lâ of pipe 3L 50 The iiow of liquid to the Weir lip is throttled by means of. the constricted passages 4I provided provided between adjacent walls 24. Liquid for 55 ñushing, such as water, oil, or any other suitable liquid, is supplied through pipes 25 and down wardly-extending nipples 2t which deliver the liquid above the header plate and below the Weir in position, rings, as indicated in Fig. 1. 60 critical or sensitive to subsequent changes of The precipitating electrodes are shown as com level of the apparatus. prising discharge electrode members 3| , such as In the form of the invention shown in Figs. 6 wires or square twisted rods, extending axially and 7, both the Weir and the constricted passages through the collecting electrodes and supported are provided by the annular U-shaped member at their upper ends by suitable supporting frame 65 58. The upper end 52 of the inner and shorter means such as are indicated at 32, 33 and 34 in Fig. 1. The collecting electrodes are ordinarily main tained at ground potential, while the entire dis weir lip, and the charge electrode system including discharge 70 The flow of liquid to the weir electrodes 3| and the associated supporting and spacing means is mounted on insulating 'sup ports, so that the necessary high potential may be maintained between the discharge and col sage 54 between the outer, longer limb 53 of the U and the inner limb 5! is further throttled in passing through the inlet openings 55. The weir lip may be adjusted to and maintained in level 75 position by means of suitable leveling blocks 56. 2,412,912 The level of the liquid in the liquid compart ment is maintained at a substantial height above the'level of the Weir lips in the collecting elec trode structure, varying in accordance with the rate of iiovv desired on the inner surfaces of the collecting electrodes and with the eñective fric tional resistance of the constricting passages. In general, a hydraulic head of from about 1/2 inch to about 4.- inches will be found to be suitable. In the precipitator illustrated in Figs. 8-11, the principles of the invention are applied to vertical plate collecting electrodes,Y consisting for example of concrete plates 60, spaced from com plementary discharge electrodes El. Along the tops of the plates Sil are horizontal troughs 62, communicating with end troughs'63 supplied with iìushing liquid by pipes 64. viding a Weir at the upper end of said electrode member and extending along the upper end of said collecting surface, means providing a liquid reservoir adjacent said Weir and a corrugated curtain member extending from substantially below to substantially above the level of the Weir and contacting the Weir means to provide con stricted passages for the ñovv of liquid from the reservoir to the Weir. , i 2. A collecting electrode for use ' in liquid flushed electrical precipitators comprising. a. vertically-extending pipe, means providing a. circumferential Weir at the upper end of the pipe, and a vertically corrugated cylindrical member circumferentially contacting the Weir means t'o provide a plurality of constricted passages for the flow of liquid to the Weir. 'c , . _ ' 3. A collecting electrode for use. in liquid flushed electrical precipitators comprising a. lecting surfaces of plates 60 is formed by the upper edges of the side members of troughs 62. 20 vertically-extending pipe having its upper end portion flared to provide an upper edge of mate Corrugated strips 65, held in position against the rially greater inside diameter than the major sides of the troughs by stiff strip members 66 and portion of the- pipe, means providing a circumfer leaf springs B1, shown more particularly in Figs. ential Weir at said upper edge of the pipe, and a 10-11, provide a series of constricted liquid flow 25 vertically corrugated cylindrical member circum passages to the Weir lips. ferentially contacting the Weir means to provide .In the embodiment of the invention shown in A The Weir lip along the top of the vertical col Figs. 12-13, vertical wall members 10, 1li’ form a plurality of constricted passages for the flow ing rectangular vertical gas passages form col of liquid to the Weir. Y .Y i, 4. A collecting electrode for use in liquid lecting electrode surfaces complementary to dis charge'electrodes 1|. The upper edges of the 30 flushed electrical precipitators comprising a vertically extending pipe, means providing `a cir horizontal troughs 'l2 forming liquid reservoirs at cumferential Weir at the upper end of the pipe, the top of the rectangular gas passages are bent means providing a reservoir for. liquid adjacent away from the gas passages to provide Weir edges the upper end of the pipe, and means providing 13 spaced apart a greater distance than the Width of the passages to reduce the velocity of the gases 35 a plurality of constricted passages substantially at the level of the Weirs. Liquid is supplied by equally spaced along the Weir for the ?loW of pipes 14. Corrugated strips ‘l5 are maintained in liquid from the reservoir to the Weir. position at the back of the Weir edges as shown 5. A collecting electrode for use in liquid in Figs. 10-11 or by other suitable means to pro flushed electrical precipitators comprising a vide constricted passages for liquid flow to the 40 vertically extending electrode member providing a'collecting surface of extended' area, means pro Weirs. Y It Will be seen that the principles of the in viding a Weir at the upper end of said electrode vention may be applied in a Wide variety of forms member and extending along the upper end of which are characterized by the provision of a said collecting surface, means providing a liquid Weir and means for constricting the ñoW of liquid 45 reservoir adjacent said Weir, and means provid- f to the Weir as defined in the claims. ing a plurality of constricted passages substan- i tially equally spaced along the Weir for the flow " We claim: l. A collecting electrode for use in liquid of liquid from the reservoir to the weir. flushed electrical precipitators comprising a vertically-extending electrode member providing 56 a collecting surface of extended area, means pro WALTER MALCOLM SCHMIDT. DONALD K.V TOWNSEND.