US2567899A - Electrostatic precipitator - Google Patents

Description

Sept. 11, 1951 R. w. WARBURTON 2,567,399

ELECTROSTATIC PRECIPITATOR Filed June 29, 1949 2 Sheets-Sheet 2 IN V EN TOR. 24 Y M [444x15 were/v Patented Sept. 11,1951

Ray W. Warburton, Medfield, Mass., assignor to Westinghouse Electric Corporation, East-Pittsburgh, -Pa., a corporation of Pennsylvania.

Application June 29, 1949, Serial No. 101,947 I,

17 Claims. (01. 183- 7) 1 I This invention relates to -electrost'atic precipitators for removing small foreign particles from-fluids. The usual electrostatic preci'pita'tor used for removing small foreign particles such as dust, irom gase's such as air, contains closely spaced, metal collector plates to which electrostatically charged 'dustparticles-are attracted. -Adisadvantage 'o'f such a construction is that when the collector plates'are loaded withcollected matter,

they are difficulttd clean. l lihis invention avoids the necessity for cleanin'g .collec'tor electrodes by constructing the collector electrodesof material which isxso inexp'ensi vethat it is economical to removeand discard them when they are loaded with collected foreign matter.

i feature of th'e invention is that the collector electrodes are assembled as a collector-cell which as easily :removed and replaced in :an electro- 1 Static ipre'cipitator.

senother .feature of the inv'enti'on is that the electrical connections to the high voltage, :direct current, 'power supply are automatically com- .;pleted when the collector cell .is inserted into-its working position .in its :ass'ociated electrostatic precipitator.

-?An object er the invention is to :reduce the manufacturing cost of electmstatic :precipi tators.

Another object of the invention is to reduce -the maintenance cost of electrostatic precipi- .tators.

Another object .of the invention is to overcome the' necessityforacleaning the collector electrodes f -;'electrostatic precipitators.

Jrnother object :of the invention is to provide an inexpensive disposable, collector electrode as- :sembly for =an-electrostatic precipitator.

The .invention'will now be described with reference to the-drawing, of which:

1:'is1a--side elevation, partiallyninisection, of electrostatic ipr'ecipitator embodying this invention;

Fig. 2 .is aiprojectedwiew, partially exploded, of a portion of "the collector electrode assembly 50f Fig.1;

3 a (plan View .of tone of :the grounded discs of ithe collector electrode assembly;

is a plan view @of one of ithercollector electrode :stanipings 20f the collector electrode assembly;

, EE-Zlg. :5 isla plan view of sneer the spacers used in the collector electrode assembly, and

.Fig'. :6 :is ca aplan view of mic-pf :the discs use in the oollector electrode assembly :for making electrical contact with the charged, centrally extending rod of the assembly.

This invention. utilizes electrode members of semi-conductive material for the collector electrodes of .an electrostatic precipitator, the'members having stamped or crimped portions for providing extended fluid contactingsurface. The members :arestacked, and are electrically interconnected, the opposed electrode surfaces of adjacent members having voltages thereon which are provided by voltage drops .caused by current flow through the members whereby electrostatic fields between the opposed surfaces are established.

'Referring now to Fig. 1 of the drawing, a cylindrical metal casing 5 has an open upper end onwhichis fitted the metal cover 6 which-has a gas inlet 1 of reduceddiameter centrally in its upper end. The lower portion of the casing is formed as a cylinder of reduced diameter and hasthe gas outlet 8 in its lower end. 7

The rods '9 extend cross-wise the interior of the cover 6 and are attached at their ends to its inner surface. They extend through the upper portion of the electric insulator l0 and support same from the cover.

The metal'rod I l is attached to the insulator l0 and extends along the longitudinal axis of the casing 5. .fIhe very thin, metal disc 12 is clamped between the clamping discs l3 just below the insulator l0. The'disc l2 has sharp edges which are spacedl'from the interior surface of the easing 5 and, forms an ionizer electrodeas will be described in the following.

-Attached tocthe rod I l at equally spaced intervals are the electrode discs [5 which have the central openings l6 thereinbetween which extend the disc portions I! which contain the circular central openings I8 having-slightly smaller diameters than the'diameter of the rod whereby they may be force-fitted thereon.

The uppermost disc 15 isspaced from the lower disc l3 by the collar l9, and it may have the sleeve 20 attachedtoits upper portion, and which may. have threaded therein the screw 2| extending through the .rod H for securely fastening the uppermost disc [5 to therod for apurpose to'be described in the following.

- Arranged centrally between adjacent electrode discs I5 are the discs 22 which havelthe central openings 23 which are placed centrally around the rod II, and which have the extensions 24 .which contact the interior surface of the casing 5. :Arranged betweeneach disc 15 and an adjacent disc '22 arain'the embodiment of the invention illustrated by the drawing, three electrode members 25 separated from each other by the spacer discs 25 which have the central openings 21a therein.

The electrode members 25 are circular and have the central circular openings 21 therein. They have the fiat portions 28 extending in planes perpendicular to the rod II with radially extending edges; have the fiat portions 29 extending perpendicular to the portions 28 at the radially extending edges thereof, and have the flat portions 30 extending between the portions 29 at points equally spaced from the fiat portions 28. The members 25 may be stamped from fiat sheets or may be molded or cast in the shape illustrated or other desired shapes providing the same extended surface function.

The electrode discs I5, 22 and 2B and the electrode members 25 are formed from semi-conductive material, or said in another way, of material having a relatively high electrical resist! ance. This material may be stiff cardboard containing dispersed metallic salts or particles, or may be a urea or other synthetic plastic. It may be a non-conductor, coated with a semiconductive material such as a thin layer of high resistance carbon.

The lowermost disc 40 is a circular disc having a central opening M and has a sharp outer edge which contacts the inner surface of thecasing 5.

The lower end of the rod II is terminated in a-plug which is fitted into a socket formed by the inwardly biased strips 32 of spring metal attached to the upper surface of the insulator 33 which is attached to the interior of the lower portion of the casing by the spaced arms 36. The socket strips 32 are electrically connected to the wire 34 which extends through the grommet 35 fitted in an opening in a wall of the casing, to a terminal, which may be a +12,000 volt terminal, of a suitable high voltage, direct current, supply source which is not illustrated, and the negative terminal of which may be grounded and connected to the casing 5 of the precipitator.

The discs I5, 22, 25 and 40 and the electrode members 25 are assembled by cementing their contacting surfaces together following which they are placed on the rod in the position illustrated by the drawing, the crew 2| then being inserted and tightened. This secures the electrode assembly securely to the rod. The rod with the attached electrode assembly is then inserted in the casing 5 as illustrated by Fig. 1 of the drawing, the plug end of the rod automatically being connected electrically to the high voltage supply wire 34 when it is in position, and the extensions 24 of the discs 22 automatically making contact with the interior surface of the casing.

The spacings between portions of the electrode members 25 and the electrode discs I5, 22 and 24 which they contact, provided by the perpendicular portions 29 thereof, form gas passages each bounded as best illustrated by Fig. 1, and the lower portion of Fig. 2, by two pairs of opposed walls provided by surfaces of the electrode members 25 and by the discs. These passages connect at their inlets formed at their outer edges, with the gas inlet passage extending from the gas inlet I around the discs and the electrode members and between the outer edges of same and the interior surface of the casing 5, and connect at their inner edges with the central gas outlet passage aligned with the openings I6, 23 and 21a in the discs, the open- 4 ings 21 in the electrode members 25, and the outlet 8. The gas flow through all of the gas passages is indicated by the arrows of Fig. l of the drawing.

In operation, the gas entering the inlet l' is ionized by the electrostatic field between the sharp edges of the disc I2 and the adjacent inner surface of the casing 5, whereby the foreign particles entrained therein are given positive electrostatic charges.

Electric current flows between the discs I5 which contact the positively charged rod I I, and between the discs 22, the extensions 24 of which contact the grounded casing 5, in paths which include the discs I5, the electrode members 25, and the discs 22 and 26. This current flow produces voltage drops in these paths, which establish voltages along different points along the paths which vary between 12,000 and zero volts depending upon their positions. Thus the opposed boundary walls of the horizontal gas passages illustrated by Fig. 1 of the drawing; have different potentials thereon which result in electrostatic fields therebetweemthese fields causing the electrostatically charged dust particles passing through the horizontal gas passages to be deposited upon the charged walls thereof.

When the collector cell has become loaded with collected matter, it is a simple matter to remove the cover 6 from the casing 5 and to pull-out the collector cell assembly attached to the rod II. The screw 2I can then be loosened and the cell assembly removed and replaced by a previously assembled clean one.

When the collector cell assembly is removed from the casing 5, the sharp edge of the lowermost disc 40 scrapes the inner surface of the casing thus removing the collected matter adhering thereto.

The collector could be used for cleaning liquids in which case the ionizer disc would be omitted.

While one embodiment of the invention has been described for the purpose of. illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated, and described, since modifications therefrom may be suggested by those skilled in the art, without departure from the essence of the invention.

What is claimed, is:

1. A collector cell for an electrostatic precipitator comprising a plurality of spaced, aligned, parallel, collector electrodes having surfaces" of electrically semi-conductive material, said electrodes having central, aligned, gas flow openings therein, a rod or tube like member of electrically conductive material extending centrally through said openings, means attaching one of said electrodes to said member, and means attaching other of said electrodes to said one electrode.

2. A collector cell for an electrostatic precipitator' comprising a plurality of spaced, aligned, parallel, collector electrodes having surfaces of electrically, semi-conductive material, means electrically connecting said electrodes together, said electrodes having central, aligned, gas new openings therein, a rod or tube like member of electrically conductive material extending'ce'ntrally through said openings, means'inclu'ding said member for applying an electrical charge of one polarity to one of said electrodes, and means for applying ,an electrical charge of the opposite polarity to another of said electrodes.

3. A collector cell for an electrostatic precipitator comprising a plurality of spaced, aligned,

parallel, *cdllctor electrodes naving' surfaces of electrically, v semi-conductive material, said electrodes "having central, aligned, gas fiow openings therein, a rod or tube like member of electrically conductive material extending centrally through saidopenings, means attachingone ofssaidielectrodes to said member, means attaching .othersof said electrodes to said--one--electrode, means for applying an electrical charge of one polarity to said member, and means for applying an electrical charge or the opposite polarity'to one ofsaid others of said electrodes.

4. A collector electrode for an electrostatic precipitator having surfaces of electrically semiconductive material and having a central gas flow opening therein, said electrode having a first plurality of surfaces spaced apart around said opening in one plane, and having a second plurality of surfaces spaced apart around said opening in another plane parallel to said plane, the said surfaces of said second plurality being aligned with the spaces between the said surfaces of said first plurality, said electrode having surfaces perpendicular to said planes extending between said surfaces of said first and second pluralities.

5. A collector cell for an electrostatic precipitator comprising a plurality of spaced, parallel electrodes having surfaces of electrically, semiconductive material and having aligned, central, gas flow openings therein, a rod or tube like mem ber of electrically conductive material extending centrally through said openings, and means for assembling said electrodes to each other and to said member.

6. An electrostatic precipitator comprising a casing, a plurality of spaced, parallel electrodes having surfaces of electrically, semi-conductive material, in said casing, said electrodes having central, fluid flow openings therein and having outer edges spaced from the interior of said casing, a rod or tube like member of electrically conductive material extending centrally through said openings, means insulatedly supporting one end of said rod from said casing, means attaching one of the outer of said electrodes to said member, means attaching the others of said electrodes to each other and to said one electrode, the other outer electrode having an extension contacting the interior of said casing, and means for applying electrical charges of opposite polarities to said member and to said casing.

7. An electrostatic precipitator comprising a casing having a gas inlet, a plurality of space, parallel collector electrodes having surfaces of electrically, semi-conductive material, in said casing, said electrodes having central, gas fiow openings therein and having outer edges spaced from the interior of said casing, a rod or tube like member of electrically conductive material extending centrally through said openings, means insulatedly supporting said member from said casing, means attaching one of the outer of said electrodes to said member, means attaching the others of said electrodes to each other and to said one electrode, the other outer electrode having an extension contacting the interior of the casing, means for applying electrical charges of opposite polarities to said member and casing, and an ionizer electrode connected to said member adjacent said inlet, said ionizer electrode having sharp edges spaced from the interior of said casing.

8. An electrostatic precipitator comprising a casing having a fluid inlet, said inlet having a removable eaver therearouiid, a plurality ei spaced, parallel collector electrodes having sur faces of electrically,- semiconducti-v'e *material, in

- said casing, said electrodes h'avi'ng central,fluid flow openings" therein and having outer :--edges spaced from the interior-"of said "casingfla rodor' electrical charge to said member includes 7 a.

socket or jack like member into which the end of the first mentioned member opposite said cover is fitted and which is insulatedly supported from said casing.

10. An electrostatic precipitator comprising a casing having a gas inlet and a gas outlet, said casing having a removable cover around said inlet, a plurality of spaced, parallel collector electrodes having surfaces of electrically conductive material, in said casing, said electrodes having central, gas flow openings therein and having outer edges spaced from the interior of said casing, a rod or tube like member extending centrally through said openings and having one end adjacent said inlet and having its other end adjacent said outlet, means attaching one of the outer of said electrodes to said member, means attaching the others of said electrodes to each other and to said one electrode, the other outer electrode having an extension contacting said casing, means insulatedly supporting said one end of said member from said cover, a socket or jack of electrically conductive material removably supporting said other end of said member and insulatedly supported from said casing, means for applying electrical charges of opposite polarity to said member and said casing,{ and an ionizer electrode connected to said member between said inlet and said electrodessaid ionizer electrode having sharp edges spaced from the interior of said casing.

11. A collector cell as claimer in claim 1 in which each of a plurality of the electrodes has surfaces extending in spaced parallel planes perpendicular to said member, and has other surfaces extending perpendicular to said planes.

12. A collector cell as claimed in claim 2 in which each of a plurality of the electrodes has surfaces extending in spaced parallel planes perpendicular tosaid member, and has other surfaces extending perpendicular to said planes.

13. A collector cell as claimed in claim 3 in which each of a plurality of the electrodes has surfaces extending in spaced parallel planes perpendicular to said member, and has other surfaces extending perpendicular to said planes.

14. An electrostatic precipitator as claimed in claim 6 in which each of a plurality of the electrodes has surfaces extending in spaced parallel planes perpendicular to said member, and has other surfaces extending perpendicular to said planes.

15. An electrostatic precipitator as claimed in claim '7 in which each of a plurality of the electrodes has surfaces extending in spaced parallel planes perpendicular to said member, and has other surfaces extending perpendicular to said planes.

16. An electrostatic precipitator as claimed in claim 8 in which each of a vplurality of the electrodes has surfaces extending in spaced parallel planes perpendicular to said member, and has other surfaces extending perpendicular to said planes.

1 17. An electrostatic precipitator as claimed in claim 10 in which each of a plurality of the col- 7 lector electrodes has surfaces extending in spaced parallel planes perpendicular to said member,

and has other surfaces extending perpendicular to said planes.

Thecfollowing references are of record in the file of this "patent: 1 .7 p

10 Number FOREIGN PATENTS Country" Date France Nov; 20, 1926

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