US1478798A - Apparatus for electrical treatment of gases - Google Patents

Description

Dec. 25', 1923. 1,478,798

. v A. SCHMIDT- APPARATUS FOR ELECTRICAL TREATMENT OF tinsss Filed May 27. 1919 2 Sheets-Sheet 1 IN VEN TOR diam/2,141

A TTOHNE V ecu 259 A A sCHMlDT APPARATUS FOR' ELECTRICAL TREATMENT OF GASES Filed May 27 191.9 2 Sheets-Sheet 2 A TTORNEY of 2-2, Fig. 4;

Patented Dec. 25,1923.

UNITED STATES PATENT orrics.

ARTHUR A.-'1, OF LOS ANGELFS, CALIFORNIA, ASSIGHOB '10 INTERNATIONAL PBEIPITATIOH COMPANY, LOS ANGELEs, CALIFORNIA, A GORPOEATIOR" 0] CALIFORNIA.

APPARATUS FOR ELEOTBIOAlZ 133mm 0! Application on my 27, 1919. Serial No. accuse.

To all whom it may concern:

Be it known that I, Aurnun A. Sonnm'r, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and .State of California, have invented a new and useful Apparatus for Electrical Treatment of Gases, of which the following is the specification.

This invention relates to the art of separato tion of suspended particles such as smoke, fume, etc-., from furnace gases, or other gases, by the action of an electric field. In such apparatus the gas to be treated is passed between suitable electrodes between which a high potential difierence is maintained, under such conditions that the material suspended in the gases is caused to be precipitated on certain of such electrodes, usually referred to as collecting or receiving electrodes. Such collectin or receiving electrodes in apparatus 0% this character are generally constituted by the walls of the chambers or passages through which the gas is conducted. The main object of the prescut invention is to provide anelectrical precipitator of improved construction wherein the walls constituting the collecting electrodes are constructed in such manner as to provide a maximum collecting surface for a given size treater. A further object of the invention is to fprovide improved means for equalizing the ow of the gases through the multiplicity of' passages in. the electrical precipitator. v

88 Another obtiect of the invention is to provide improve means for removing the re? cipitated material from the walls or sur aces constituting the collecting electrodes.

' l The accompanyi drawings illustrate.

embodiment of my invention, and referring .thereto:

Fig. 1 is a vertical section of the apparatus taken on line 1-1, Fig. 4. Fig. 2 is a vertical section taken on'line Fig. 3 1s 'a-horizonta'l section taken on line 3-3, F lg. 2. i 4

Fig. 4 isa horizontal section taken on line 4-4,.I i 2.

5 is a vertical section of one of the cleaning brushes.

Fig. '6 is a side elevation and Fig. 7 an end.

elevation of a, plurality of hunters provided municate wit able manner and are pre with means for automatic operation of same in cyclic order for precipitation and for removal of the precipitate.

Fig. 8 is a partly sectional side elevation and ig. 9 an end elevation of one of the valve devices for controlling such c clic operation, said Fig. 9 being taken on line 99,

Fig. 6.

- he apparatus shown comprises an outer casing it having vertical walls 1, a closed top ,2, and a hopper shaped bottom 3, provided with suitable means such its gate a for re moving collected material. A horizontal partition 5 extends across the outer casing to orm a top header or chamber 6 into which \-opens a conduit 8 for conducting the gas to or from the apparatus. Another conduit .0; fine 9 leads fromthe lower part of the c In the following description the gases be assumed to enter at the upper conduit 8 and be discharged through the lower conduit 9, but the direction of the gas stream may he reversed if desired. The outer casing 1 may be mounted on suitable supporting columns 10. v

Aplurality of vertical gas receiving flues 12 are mounted in connection with the transverse horizontal partition 5, aforesaid,said flues beingo en at their lower ends to comli the space 13 at the lowergart of casing. 11. and open at their up er en to communicate with the upper he er 6. For the sake of compactness, I prefer to form, these vertical lines of hexagonal shape, as shown in Fig. 4, assembled in close order in such manner as" to give a cellular or reticulate construction similar to that of a honeycomb structure. The walls of these hex-- agonal fines may be formed of 'sheet metaland may be fastened to ther in any sultrably connected at .their upper and lower ends to frames 14 and 15 for mounting thesaine. If-desired, these flue's may be formed in aplurality of sections 0 and d, separated as indicated at 16. These collecting electrodes or flues rnay ri 'dly mounted in statibnarypo'srtxon in ca? 0, but tofacilitste cleann g the same 1' pre er to mount the said time in such mam.

'. nor" as to enable them to .be raised or lowered as hereinafter described; The hopper or mceptacle 3 is permanently connected below the said fallingfromthesaidwhuherat thetimesofcleaningoratothertinmwill fall'into said receptacle Discharge electrodes 20extend vertically and axially in the respective lines 12, said dischal' electrodm consisting, for example,

ofm 'cwiresorrodsofsmtablefineness to 't electriull therefrom at the potential difference under which the apparatus is to be operated-raid discharge electrodes being held rigidly, behveen upper insulator frame bars or beams 22 and lower insulator frame bars 23, connected to the upperand lower ends of the discharge electrodes. The supporting'bars'22 and 23 are mounted on suitable insulators 27 and 28 which are secured in fixed position in suitaing arranged in rows or sets above the re-- spective sets and (d) of Hum. The said sets of fines (a) and ((1), together with their upper and lower frames 14 and 15, and.

vertical connecting bars 25, constitute a rigid body, which is guided vertically by guide rollers or wheels 32 on which run the vertical i'rsme bars 25. Any suitable'lneans may he provided for raising the collecting I electrode system to efiect the cleaning theretill so, from whi nected to a wire 43 leading to anysuitabloj of, tier example, a hydraulic ram comprising a cylinder 34 and a plunger 35, connected by cable 38 r g on sheaves 3910 a frame epend bars 37 connected to the respective cs 14 and 15, so as to hit the collecting electrode bodily by the action of the hydraulic ram. Brushes 31 may be form@ in annular or polygonal shape to fit the walls of" the collectin electrode tines and are mounted on spi em or open as 31?, so as to permit p of gas through same and also, in case of the lower brushes, to permit of the precipitated matenal p downwardly through the brushes in cl 1 collecting electrode system is normally supported on cross-beams 40 on which the lower frame rests and a horizontal extension plate constituting'the transverse horizontal partition aforesaid is attached to the upper frame 14 and norinall extends directly over 42 on the weld of easing 1. discharge electrode system is cdnsource of current, for example, saidwire may be so phed with currentin the manner set forth in patent to F. G. Cottrell, No. 895,729, August 11th, 1908 in such manner of the apparatus. The

as to maintain a unidirectional high potential difi'erence between the discharge electrodes and the collect electrode lines 12, the latter being un ed and the current being completed t lrough grounded connections at the source of current.

I prefer to provide for automatically cutting oil? the electric current supply and also the supply of gas to the apparatus during valves or dampers 51. and 52 are provided at the inlet flue or conduct 8 and outlet flue or conduct 9 of the apparatus and are connected to levers 53 engaged by frame 36 to close the dampers when said frame is raised and to'open the dampers when the frame is lowered to normal position. The cleaning operation may be performed intermittently or periodically "by time controlled mechanism, and, in case of a plurality of precipitators in a single installation, I prefer to provide for successive cleaning operations in the several precipitators -in cyclic manner. Suitable means ion this purpose is shown in Figs. 6 to 9, comprising a. pluralityot valves 55, 56, 57 and 58, connected by pipes 59 to ram cylinders 34 for the respective precipitators, and operated by cams 61, 62, 63, and 64, respectively, v

carried by a shaft 65, which is rotated at low speed by gearin 66 operated by motor 57. Each of said va vcs, when operatedby the corresponding cam, opens connection from a water pressure supply pipe 68 to the corresponding pipe 59 and when the valve is returned to normal position by a spring 69, it opens connection from said pipe 59 to outlet pipe 70, to allow the ram plunger to return to normal position. The cams 61, 62, etc, are angularly displaced around shaft 65 so as to cause successive operation of'valves 55, etc., and operation in cyll order of the cleaning means for the several precipitators, so that the precipitators are cleaned one at a time.

The operating of the apparatus is as fol-- lows 4 The gas to be treated is supplied, for ex ample, through flue 8 and passeskdownwa wardly through the successive sections b and c of the collecting electrode fines and then out'throu h flue 9. Normally'the collectingelectr e system is supported on the supporting I beams 40 with the upper plate 5 extending from frame 14 resting on or' lying directly over flanges 42 on the enclosmgcasmg 1 so as to cause all of the gas to Ell n t-1am be directed through-the collecting-electrode fines. A suitable high potentialdiflerence, say 50,000 volts or over, is maintained between the discharge electrodes 20 and the collecting electrode lines 12- and the suspended material or suspended; particles are precipitated on the walls of the collectin electrode flues by the action of the ectrical field so produced, in such manner that .the gases which pass out through the outlet 9 are comparatively clean or free of suspended material. An im ortant advantage of the construction described wherein the collecting electrode flues are made in a plurality of sections with open spaces between is that better equalization or distribution of the gases is secured between the parallel fines. Inapparatus of this kind including a multiplicity of parallel lines there is generally a tendency for the gases 0 the I to flow more rapidly through some fines than others, either on account of unequal heat distribution, resulting in difierence in density or buoyancy of the gases, or on account of disturbances due, for example, to outside influences, such as wind or at'- mospher'ic currents; these disturbing or unf the length equalizin influences generally increase with of the vertical lines and by dii ing thefiues in a plurality oi'sections opportunity is given for the gases to equal-' ize themselves as regards velocity, pressure. and temperature between the several flues;

' The material deposited or precipitated on the walls of the-collectiug electrode flues maybe removed continuously or from time to tim by any suitable means. With the construction shown in the drawing, such removal is conveniently efiected by raising the entire collecting electrode system bodily at stated or required intervals by operation of therein 34, or otherwise, causing each section of theelectrode dues to be drawn up past the brushes 31 in such manner that the precipitated material is brushed .or dis lodged fromthe walls of the lines and descends by gravity to the bottom of the treatthe cleaning operation 'is being er. To facilitate this operation, it is preferable to cut off the supply of current'while performed and the draft may also be out Q or reduced at such time. In..this connection, it. is-to be noted that the introduction ofthe brushes within the respective collecting electrode fines tends of itself to diminish the effective cross-section of the lines as regards passage of the gases therethrough so that the draft 1 through the inlet and outlet pipes will be automatically reduced during the cleaninqg operation, the brushes. acting as parti dampers in the fines and then again on lo ering thecollect ng electrode system the cleaning operationis repeated and the sys-' tem finally comesto rest in normal position,-be ng.then supported on the beams 40.

I prefer, however, to also. provide ositive dampers, as shown at 51 and 52 at t e inlet and outlet, or both, and to operate said dampers concurrently with the cleaning etc., are operated successively by the cams 61, etc., to cause succemive operation of the cleaning means for the respective precipita-. tors an correspond precipitator by opemn switch 50 an to stop the gas flow throng to the prccipitator, c osing valves 51 and 52 soas' to shut ofi' communication .with inlet flue 'Z3'and outletflue 74. v This provides for automatic and periodic control of the cleaning means and for shutting oil of thogas stream and of the electric current durin the cleaning, and the expense of manna control is thereby obviated and it is thereby rendered practicable toefiect cleaning at short intervals, (say of a few minutes duration), and to thereby keep the collecting electrodes in relatively clean condition. This contributes materially to efiiciency of precipitation, as electrical precipitation is ar more effective when the collecting electrade is substantially clean than when a doalso to cut oil the current to the positof considerable thickness has been 7 proximate uniformity of electric field and maximum effective precipitating capacity for each flue, together with complete utili 7 zation of the treater spaces and elimination of waste spaces such as are generally found in the ordinary round pipe treaters by reason of the pipes.

While the above described apparatus is intended particularl for electrical precipitation of suspende necessary separation of the material from gases,

some oi the -fatures of the invention, particularly,,the hexagonal cellular electrode flue system and the arrangement 1 of the electrode 'flue' system in a plurality of 8110- i cessively acting sections spaced apart to permit equalization of the gases, are applicable enerally to electrical treatment of gases or various cal reactm r An important'feature of-the present in v vention, as applied to electrical-precipitation, is the provisionior removing the -de-' posit from the collecting means such as brushes, which are normally removed from the said electrodes so as not purposes, such as electro-chemi electrodes by to interfere with tions 0 plrec'i itation and to leave the precipitation 0 am rs free for effective (iperation throughout the collecting surfaces.

I; will be understood that the term brush ing means, as used herein, includes any suit ab e means for brushing,'scraping orotherwise positively removing the deposit from the collecting electrodes. It will also be un derstood that the relative motion of the brushing means and the collecting electrode means required for the cleaning operation may efiected by moving either of such means. Thus, for example, the discharge electrode system may be mounted to move relatively to the collecting electrodes to bring the brushes into operative relation for cleaning and, preferably, at the same time, to open the circuit connection to the supply circuit, substantially as above described-for the collecting electrode system.

What Iclaim is:' e

1; In an apparatus for the electrical treatment of gases, a plurality of parallel discharg electrodes and a plurality of seccollecting electrodes, each section of collecting electrodes comprising a plurality of parallel fines respectively surrounding said discharge electrodes, and said s'ections bein spaced apart to permit interflow and e uahzation of the gases between the-= 7 severe flues of the sections, and means for conducting the gases to and from the said collecting electrodes. 2. .In an apparatus for the electrical precipitation of suspended material from gases the combination of a plurality of vertica discharge electrodes and a collecting electrode system, comprising a plurality of sections, each section consisting of a plurality of vertical collecting electrode fluessurrounding the respective discharge electrodes, said sections being spaced apart vertically, means for conducting gases to one of sa d sections, and means for conducting gases Y away from another of said sections, whereby the gasis caused ,to pass successively through said sections andtobe equalized between the diiferent flues of each section;

3. Inan apparatusfor the electrical'precipitation of suspended' material from gases, the combination of a vertically extending discharge electrode, a vertically extending collecting electrode tzpposingthe I same, brushing means moun in xed position adjacent to vaaidcollect electrode, means 'for reciprocating said col ecting electrode in a vertical path to cause it to be brought into.

' contact with'said brushing means orout of contact therewith and a'receptacl'e permanently located below said collecting electrodes to receive the precipitated material removed therefrom.

4.- In an .apparatus for the electricalprecipitation'ofsuspended material from gases he combination of a'verticglly extending discharge electrode, a collecting electrode extending vertically opposite the discharge electrode, cleanin means mounted on said discharge electrode for removing preci itated material from said collectin electrode, and means for reciprocating sai collecting electrode adjacentvto said cleaning means to cause cleaning of the electrode by said cleaning means.

'5. The combination of an electrical precipitator comprising electrodes and .means for supplying said electrodes with high tension current, so as to maintain the -electrodes at high potential difference; means for cleaning the electrodes; means for periodically operating said cleaning means, and switch means for controlling supply of' current to the electrical precip1tator,and means automatically operative to maintain said switch open during the operation of the cleaning means.

6. The combination of a collecting electrode,"a discharge electrode, cleanin means for the collecting electrode, means or periodi cally operating said cleaning means, and

'maticallyso as to be open during the cleanin operation, i I I In an apparatus for the electrical precipitation of suspended material from. gases,

'electrode means for effecting electrical action on the s to precipitate suspended particles there rom, a conduit for conducting the gas to-.be treated between said electrode means, damper means controlling the fl ow of gas in said conduit, automatic cleaning means for the removal of. the precipitated material from the collecting electrodes, periodically operating means for controlling the operation of said cleaning means at definite intervals and means for efiectin operation of said damper means simu taneously with said cleaning means at? shut off the flow ofgas during the cleaning oper ation.

8. In an apparatus for the electrical precipitation of suspended material from gases, a" plurality offe ectrical precipitation units, each provided with automatically operated electrode" cleaning means 'for removln the reci itated material, conduits for con mi:-

ing t e gas to be treated to the respective electrical precipitation units, periodically operating means controlling the operation of said automatic'cleanin' mean's successiv'ely for the'respective e ectrical recipimeans for operating the'damper means for the conduit leading to each'electrical pron cipitation unit simultaneously with'the op eration .of the cleaning ,means for such un t.

9. In an apparatus for removing 8- ggnded particles from gaseous and fluid flow dies, the combination with a stationary discharge electrode and a reciprocable collecting electrode of means arranged to con- 6' tact with the collecting surface of said last .named electrode to scrape said surface when said electrode'isreciprocated. v

'- 10. In an apparatus for removing suspended particles from gaseous and fluid flow l0 bodies, the combination with a stationary contact with the inner periphery of said c ollecting electrode to scrape the same when said electrode is reciprocated.v

In testimony whereof I have hereunto subscribed my name this 20th day of May, 1919;

ARTHUR A. SCHMIDT.

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