US1569595A - Apparatus for electrical precipitation of suspended material from gases - Google Patents

Description

Jan. 12 1926. 1,569,595

S F. H. VIETS APPARATUS FOR ELECTRICAL PRECIPITATION OF SUSPENDED MATERIAL FROM GASES Filed April 15, 1925 3 Sheets-Sheet 1 62 ch p 44,:

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F. H. VlETS APPARATUS FOR ELECTRICAL PRECIPITATION OF SUSPENDED MATERIAL FROM GASES Filed April 13, 1925 s Sheets-Sheet 2 INVENTOR F/rya /7. View: 7

A TTORNE Y Jan. 12 1926.

F. H. VIETS APPARATUS FOR ELECTRICAL PRECIPITATION 0F SUSPENDED MATERIAL FROM GASES 3 Sheets-Sheet 3 Filed April 15, 1925 VINVENTOR. F/oyd h. V/efs M W /M ATTORNEY.

Patented Jan. 12, 1926.

UNITED STATES PATENT OFFICE.

FLOYD H. VIETS, OF ALHAMBRA, CALIFORNIA, ASSIGNOR T INTERNATIONAL PRE- CIPITATION COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALI- FORNIA.

APPARATUS FOR ELECTRICAL PRECIPITATION 0F SUSPENDED MATERIAL FROM GASES.

Application filed April 13, 1925. Serial No. 22,848.

To all whom it may 0011 cam: I

Be it known that I, FLOYD H. Vnams, a citizen of the United States, residing at Alhambra. in the county of Los Angeles, State of California, have invented a new and useful Apparatus for Electrical Precipitation [of Suspended Material fromGases, of which the following is a specification.

This invention relates to apparatus for the electrical precipitation of suspended part1- cles such as dust,'fume, or mist from gases containing the same and particularly to apparatus for this purpose in which the collecting electrodes are formed as plates of concrete or similar semi-conducting material. An object of the invention is to provide a novel means of supporting and grounding such a collecting electrode. Another object of the invention is to provide an integral collecting electrode plate of semi-conducting material with novel supporting and grounding means and with re-enforcing means, said reenforcing means being adapted to not only provide for effective re-enforcing but also tial to different portions of the plate. A further object of the invention is to provide an integral concrete plate electrode with or without such re-enforcing and distributing means and supported only from its upper edge so that the side and bottom edges of such plate are free from metallic supporting tion through one of the collecting electrode plates.

Fig. 4 is a broken partial side elevation of said plate. Fig. 5 is a-view similar to Fig. 4 showing a modified form of re-enforcing means. Fig. 6 is a partial longitudinal vertical bodying my invention.

for uniform distribution of electrical potensection through one of the collecting elec trode plates showing the re-enforcing means embedded therein.

Fig. 7 is a view similar to Fig. 6 showing the use of a modified form of embedded reenforcing members.

Fig. 8 is a longitudinal vertical section of another form of electrical precipitator embodying my invention.

Fig. 9 is an end elevation partly in section of the form of electrical in Fig. 8. I Fig. 10 is a partial transverse section of one of the collecting electrodes of said precipitator and the supporting means therefor. Fig. 11 is a transverse vertical section of another form of electrical precipitator em- Fig. 12 is a side elevation of one of the lower collecting electrode plates of the precipitator shown in Fig. 11.

Fig. 13 is a partial longitudinal section and Fig. 14 a partial transverse section of the upper portion of one of said collecting electrode plates showing thesupporting means therefor.

Fig. 15 is a perspective view of one of the Ushaped members used in assembling the re-enforcing members in this latter type of construction.

Referring to Figs. 1 and 2 the electrical precipitator there shown comprises a housing or chamber 1 provided with inlet means 2 and outlet means 3 for passage of the gas to be treated therethrough. Within said chamber are provided a plurality of discharge electrode means and collecting electrode means. Said discharge electrode means may comprise a plurality of vertically extending wires or other members 4 of relatively small cross-section and therefore presenting relatively small surface area and sharp surface curvature. The collecting electrode means comprise a plurality of integral plates 5 suspended vertically within the chamber 1 and preferably extending substantially parallel to the direction of the gas flow through the precipitator.

Said collecting electrode plates are composed of Portland cement concrete, plaster,

precipitator shown transite, terra-cotta, or other plaster or 0e" ment composition whose electrical conductivity is relatively low or generally of any semi-conducting material. Said plates may advantageously be supported by supporting means 6 at the upper end of eachplate, and suitable re-enforcing members 7 are pro vided for reenforcing such concrete plates and for holding the same securely to the supporting means 6. Supporting means 6 may comprise for example channel irons and said channel irons may project beyond the edges of the concrete plates and may rest on'suitable supporting means such as Z-bars 8 mounted at the top of chamber. 1. A removable cover 9 may be provided for the precipitator so that the concrete plates together with the supporting means therefor may be lowered into place on the Z-bars and said removable cover may then be placedinto position. Removable supports for said coversuch as angle irons 10 are preferably provided to facilitate the removal and replacement of the collecting electrode plates atany time. It will be understood of course that the plates do not necessarily have to be introduced through the top of the treater as above described as this particular method of assembly forms no part of the invention. For example one of the side AVZIllS of the chamber 1 may beumade in the. form of a removable curtain wall and said plates may be moved into position through the opening thus aiforded, or any other suitable method may be used for bringing the plates into position. V p r The re-enforcing members 7 may comprise rods or heavy wires and are preferably embedded or formed in the concrete plate at the time 'of pouring or molding said plates. In order to avoid difliculties arising from improper alinement of the re-enforcing members I prefer to connect said members to the supporting means 6 before molding the plate around said resenforcing means. Said re-enforcing members may be threaded at their upper ends and may project through holes 12in the supporting members 6 and. may be secured thereto bymeans of nuts 13. Any other suitable means of securing the re-enforcing members to the supporting means may however be used. The re-enforcmg members may be bent or hooked at their lower ends as at 14 in order to provide, for more effective support at this point. This is not always necessary however and in some cases said members 7 may comprlse slmply straight rods or wires as indicated in Fig. 5. It has been found in re-enforced structures of this kind that a very strong support is provided by the use of such vertical straightrods due to the contact between the concrete and the rods throughout the lengththereof.

Furthermore said re-enforcing members may comprise smooth rods as indicated in Fig. 6 or twisted rods of square or other suitable cross-sectlon as indicated in Fig. 7. Where position.

' menace an especially strong support is desired the use of twisted rods may be desirable but in many cases the smooth rods are preferable and provide sufficient supporting and re-enforcing effect. preferably extend nearly but not quite to the lower edge of the concrete plates so as to effectively support the lower portion of the plate while preventing the possibility of exposure of any metallic members at the bottom of the plate. It will be noted that the embedded re-enforcing members 7 extend parallel to the discharge electrode members 4 and as shown I prefer for the sake of uniformity of the electrical field to provide the same spacing between the said re-enforcing members and between adjacent discharge members and to space said discharge members opposite the portions of the collecting electrodes midway between the re-enforcing members. With such a construction theportions of the surface of the collecting electrode which are closest to the embedded reenforcing members are furthest from the discharge members and vice-verse and it has great uniformity of the electrical field" throughout the precipitator.

The re-enforcing members- .been found that this arrangement produces The entire discharge electrode system, c0mprising the supporting frames and the horizontal supports and discharge wires carried thereby, is supported for'example by bus bars 19 mounted on insulating supports 20 at the 'top of the precipitator chamber. Suitable means such as weights 21 may be provided at the lower ends of the discharge wires for tensioning the 'same and holding such as rods or bars 22 may be supported by the lower horizontal frame member 17 and adapted to engage the lower ends of said wires or the weights carried thereby so as to maintain the discharge members in proper In this connection it may be pointed out as one of the advantages of my construction that. the bottom edge ofeach collecting electrode plate 5 is free from metallic supporting means so that the discharge members 4 may be carried down past the bottom of the collecting electrodes without danger of excessive or disruptive discharge at this point such as is apt to occur in the presence of exposed metallic members. This feature'is of considerable advantage since it permits the locationof weights 21 and spacmg means 22 below the lower edges of the collecting electrodes instead of above such them in vertical position and suitable means lower edges and between the adjacent elec' trodes as would necessarily be the case if it were not possible to extend the discharge members beyond the bottom of the electrode plates. This not only prevents undue crowding of said weights and spacing means in the narrow space between the collecting electrodes and too great proximity between said spacing members 22 and said collecting electrodes but also permits the effective utilization for precipitation purposes of the entire lower portion of each electrode plate.

The discharge electrode system is connected for example through wire indicated at 25 to one side of a source of high tension current. either alternating or direct. but preferably rectified alternating high tension current. the other side of which source is grounded. Said source of high tension current is preferably adapted to maintain a potential difference between the discharge electrodes and the grounded collecting electrodes of from say 15,000 to 100,000 volts. The exact voltage required in any case depends upon the spacing of the electrodes and upon other conditions. The collecting electrode system is preferably grounded for example by connecting grounded wire 26 to any suitable portion of the metallic supporting' means therefor such as supporting bars 6. When so grounded it will be seen that the supporting members 6 and the re-enforcing and conducting members 7 are in metallic connection with the ground so thatall portions of the collecting electrodes are maintained at all times at substantially the potential of the earth. In some cases the metallic grounding Wire 26 may be eliminated, and the collecting electrode system grounded only by contact with the concrete housing of the precipitator. In this case also, however, the embedded members 7 serve not only to strengthen and support the integral collecting electrode plates 5. but also to maintain all portions thereof at substantially uniform electrical potential.

' Suitable means such as hopper 27 are provided at the bottom of" the precipitating chamber 1 to receive precipitated material and any suitable-means may be provided for removal of such material therefrom.

In operation the electrode system is energiaed by connection to the source of high tension current as above described. and by reason of the relatively small surface area and sharp curvature of the discharge electrodes and the relatively extended area of the collecting electrodes a silent electrical discharge is produced from the discharge electrodes to the collecting electrodes. The metallic .conducting and re-enforcing members 7 serve to produce substantially uniform distribution of electrical potential throughout the collecting electrodes due to the fact that all parts of said electrodeare substantially uniand distributing system,said system being grounded as above described either through grounded wire 26 or through the walls of the precipitator housing. The uniformity of the electrical field is further increased by the staggered or alternate arrangement of the discharge members 4 and the embedded conducting members 7 for the reasons above mentioned.

The gas to be treated is passed through the chamber 1 so as to flow between the discharge electrodes and the collecting electrodes. Under the action of the electrical field the suspended particles carried by the gas become charged and are attracted to the collecting electrodes. The material so precipitated "eventualy falls off the collecting electrodes by gravity and is collected'at' the bottom,,of the precipitator. If desired the collecting electrodes may be jarred or rapped from time to time to dislodge deposited material therefrom but it has been found with semi-conducting materials such as concrete that the deposited material adheres thereto in a relatively loose manner and therefore falls oil by its own weight before it becomes thick enough to seriously impair the efl'ective operation of the precipitator.

In some cases the collecting electrodesmay be constructed of semi-conducting material which is of sufiicient strength and rigidity to be self-supporting and therefore require no re-enforcing means. For example I may form said lates from sheets of the composition material known as transite board, said sheets being indicated at 5 in Figs. 8 to 10.

Said collecting-electrodes maybe mounted on suitable supporting means 6 at the upper edge thereof and secured thereto for example by means of bolts 28 and nuts 29. The precipitator shown in said figures com prises, as before, achamber 1 provided with lnlet means 2, outlet means 3, and hopper or other material-receiving means 27. The precipitator chamber is shown as constructed of metal in this case in order to provide as light a construction as possible. The supporting means 6 for the collecting electrodes I may as before project beyond the sides of said electrodes and rest on suitable supportmg members 8 at the top of the precipitator chamber. The collecting electrodes may be properly spaced and ,alined at their lower edges by engagement with notches 30 in the end walls 32 of the hopper, said notches serving preferably plates.

The discharge electrodes are shown in this form of the invention zontal wires 4 extending between suitable to aline but not support said.

as comprising hori supporting frames. indicated at 31, said I frames being insulated from the' precipi- I tator housing and being mounted for example on suitable'insulating supports 20. The electrical connections and operationof this form of precipitator are substantially the same as above described, the supporting means for the Collecting electrode plates being grounded for example as indicated at 26 and the discharge electrode system being limited floor space or for other connected by wire indicated at 25 to the source of high tension current, the other side of which source is grounded. The gases enter the t-reater at 2 and pass upwardly through chamber 1 and out at the top thereof, the precipitated material collecting on the plates 5 and falling intothe hopper 27.

It will be seen that the electrode plates are in this case free from embedded conducting and re-enforcing members and are supported and grounded only at their upper edge through metallic grounding and supporting means 6. It is advantageous therefore to construct said plates as shown of greater length than height so as to obtain distribution of the electrical current alongv one of the longer edges of said plate. Such a construction not only minimizes the disparity in the electrical field between the upper and lower portions of the plate but also provides a strong and rigid construction due to th fact that the plates are rigidly supported along one of the longer edges thereof.

In many cases it is desirable because of reasons to make the electrical precipitating chamber relatively high and narrow and in such cases it is sometimes impracticable in a large treaterto provide a single plate of cement or other semi-conducting material of sufficient height to extend from the top to the bottom of the precipitator chamber and at the same time obtain suflicient strength in such plate, without making the same excessi'vely heavy and requiring the use of very heavy supporting means, and also decreasing the volumetrlc capacity of the recipitator. In such cases I have found it prefer able to provide two sets of collecting electrode plates extending one above the other and to provide separate supporting means for the plates of each set. For example as showii in Fig. 11 collecting electrode plates 5 which may be'of the type shown in Figs;

1 and 2 are provided in the upper portion of the precipltator chamber 1 and collecting electrode plates 35 are stein may in such case be substantialy t e same as shown in Figs. 1 and 2, comprising vertically extending members such as wires 4 supported by suitable su porting means 16 at the upper end of t e chamber, said supporting means being mounted on frame means indicated at 1'1, 18, and 19. Said frame means may be mounted on insulating. supports 20 at the plrovided in the lower; portion of said cham err The discharge electrode amazes have any exposed metallic supporting means at saidupper edge of said plates in order to prevent arcing or concentration of the electrical field at thispoint which would result if the same method of support were used for the lowerplates as for the upper plates;

I therefore prefer to provide embedded supporting means adjacent the upper edges of said lower plates, said supporting means for each plate comprising for example a flat 'metal bar 36. Said bar is adapted to'project beyond the sides of the collecting electrode plate 35 and to rest at its ends on suitable supporting means such as Z-bars 34 at the ends of the precipitator chamber. 7 Su1table vertical re-enforcing members such as rods 37 are secured to said bars 36 in anysuitable manner and extend throughout substantially the entire height of the plate 35. The upper ends of said rods 37 may" be threaded as indicated at 38 and may project through openings 39 in. suitable U-shaped supporting members 40 adapted to be inserted. within T-shaped notches 41 in bars 36, saidre-enforcing rods being then secured 1n positlon by means of nuts 42. When.

making collecting electrode plates of this type the re-enforcing members 37 are secured to the supporting bar 36 in this manner and the concrete or other semi-conducting material is then formed around said re-enforcing and conducting frame-work so as to entirely surround all portions of the metal frame-work with semi-conducting material. In order to provide a more efiective bond between the supporting bar 36 and the semiconducting material of plate 35 said bar may be provided with circular openings 43 spaced at suitable intervals therein through which the concrete or other material protrudes so as to form an interlock between the supporting bar and the plate.

The electrical connections and the manner of operation are substantially the same in this form of the precipitator as in those' plate of semi-conduct- 1y within the plate'and secured at their upper ends to th metallic supporting member.

What I claim is:

1. A collecting electrode plate for use in electrical precipitators comprising an integral plate of semi-conducting material, a metallic supporting member extending along the upper edge of said plate, and metallic re-enforcing and conducting members extending vertically within said plate and secured at their upper ends to said metallic supporting member and extending substantially throughout the height of said plate.

2. A collecting electrode plate. as set forth in claim 1, said plate being free from metallic supporting means at its bottom and side edges.

3. A collecting electrode plate foruse in electrical precipitators comprising an integral plate of cementitious material, a metallic supporting member extending alon the upper edge of said plate, and metallic reenforcing and conducting members extending vertically Within said plate and secured at the upper ends to said metallic supporting member and extending substantially throu hout the height of said plate.

4. collecting electrode plate as set forth in claim 3, said plate being free from metallic supporting means at its bottom and side edges.

5. In an apparatus for electrical precipitation of suspended material from gases, an integral electrode plate consisting of semiconducting material, a metallic supporting member extending along the upper edge of said plate and projecting beyond the sides of said plate, metallic vertically extending conducting and re-enforcing members embedded within said plate. and secured at their upper ends to said supporting member, and means adapted to engage the projecting portions of said supporting member to support said member and the electrode plate carried thereby.

6. In an apparatus for electrical precipiing said discharge electrode means.

7. A collecting electrode plate for use in electrical precipitators comprising an integral plate of semi-conducting material and a metallic supporting member extending along the upper. edge of said'plate and cong nected thereto, the side and bottom ed es of said plate being unsupported vertica ly so that the entire weight of said plate is supported by said supporting member, and said supporting member being metallically grounded so as to ground said plate.

8. A collecting electrode plate for use in electrical precipitators comprising an integral plate of semi-conducting material, a metallic supporting member extending horizontally adjacent the upper edge of said plate and metallic re-enforcing and conductingmembers extending vertically within said plate and embedded therein and secured at their upper ends to said metallic supporting member and extending substantially throughout the height of said plate. 9. A collecting electrode plate as set forth in claim 8 in which said metallic supporting member is embedded within the semiconducting material of the plate. I

In testimony whereof I have hereunto subscribed my name this 13th day of March, 1925.

FLOYD H. VIETS.

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