US3688475A

US3688475A - Electro-precipitation

Info

Publication number: US3688475A
Application number: US19948A
Authority: US
Inventors: John F Dyla; William M Moore; Robin A Attfield
Original assignee: Lodge Cottrell Ltd
Current assignee: WLTD Ltd
Priority date: 1969-04-03
Filing date: 1970-03-16
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: FR2038234A1; DE2015717B2; DE2015717A1; JPS4922498B1; FR2038234B1

Abstract

An electro-precipitator discharge electrode support structure comprises an upper portion comprising a plurality of vertical elongated discharge electrode support masts which extend upwardly from a central region of the structure, and a lower portion also comprising a plurality of vertical elongated discharge electrodes support masts which are non integral with the support masts of the upper portion and extend downwardly from the central region. A rectangular bracing cage is provided at the central region to connect the support masts of the upper portion to the support masts of the lower portion so that relative movement between the upper and lower ends of the structure is minimized.

Description

United States Patent 51 3,688,475

Dyla et al. Sept. 5, 1972 [54] ELECTRO-PRECIPITATION 3,443,362 5/1969 Ebert ..55/152 X [72] Inventors: John F. y 3,485,011 12/1969 Archer et al ..55/148 X Moore; Robin A. Attfield both 3,570,219 3/1971 Schmitz ..55/ 148 gf x staflmdshlre FOREIGN PATENTS OR APPLICATIONS 243,343 2/1963 Australia ..55/152 [73] Assgneeff gf g a 544,384 2/1932 Germany ..55/150 338,739 11/1930 Great Britain ..l50/ [22] Filed: March 16, 1970 540,918 11/1941 Great Britain ..55/148 [21] Appl 19948 Primary ExaminerDennis E. Talbert, Jr.

AttorneyNorris & Bateman [30] Foreign Application Priority Data April 3, 1969 Great Britain ..17,631/69 [571 ABSTRACT 06L 1969 Great Britain An electro-precipitator discharge electrode support structure comprises an upper portion comprising a LS. "55/148, of vertical elongated discharge electrode sup.

Clpon masts extend from a central re- [58] Field of Search ..55/146, 147, 148, 150, 151, g of the Structure, and a lower portion also 55/152 153 prising a plurality of vertical elongated discharge electrodes support masts which are non integral with the [56] References cued support masts of the upper portion and extend UNITED STATES PATENTS downwardly from the central region. A rectangular bracing cage 18 provided at the central region to con- X nect the upport masts of the upper portion to the sup 1,846,169 2/1932 Werskopf ..55/ 148 X port masts of the lower i so that relative move :gi et g ment between the upper and lower ends of the strucy t i 3,282,029 ll/l966 Stevemagel ..55/151 X 3,350,850 11/1967 Stevemagel ..55/152 X 8 Claims, 11 Drawing Figures IQL 43 40 h u-l PATENTEBSEP 51912 3.688.475

sum 1 0r 8 m f Q I I I r IE JOHN FLORIAN DYLA,

WILLIAM MALCOLM MOORE 8| "ROBIN ARTHUR RY A'I'TFIELD 71mm 3. 5mm u YORNEY PATENTEBSEP 5 I972 3 688,475

sum 2 or 8 JOHN FLORIAN DYLAJ WILLIAM MALCOLM MOORE & ROBIN ARTHUR BY A'IJIFIELD H y *1 Haw-1n! ATTORNEY PATENTED EP 519?? 3.688.475

saw 3 or 8 infill Q 654 70 72 4Z8 7 4 4 2 4 8 Z2 g [0 & EEQZ. & Q 5 0.4.

INVENTOR JOHN FLORIAN DYLA,

WILLIAM MALCOLM & ROBIN ARTHUR ATTFIELD PATENTEDSEP 5 m2 3. 688' 475 SHEET '4- UF 8 INVENTOR ATTORNEY TETEBSEP 5 1972 3,688,475

sum 5 or 8 INVENTOR JOHN FLORIAN DYLA,

IAM MALCOLM MOORE & ROBIN ARTHUR BY ATTFIELD 7 )mm "1. :1; xi ATTORNEY PA IENTEnsEP smz 3,688,475

SHEET 8 UF 8 INVENTOR JOHN FLORIAN DYLA,

WILLIAM MALCOW MOORE s. ROBIN ARTHUR ,A'I'TF I I'll-l) IX \I I] If I 1 r \UhNl Y ELECTRO-PRECIPITATION This invention is concerned with improvements in or relating to electro-precipitators of the Cottrell type.

In the electro-precipitation of, for example, dust from gases, careful design of the electrode support structures is important. For example, problems may arise due to swinging movement of the discharge electrodes; this may lead to burning and breakage of discharge electrodes and poor discharge characteristics. Also problems may arise due to bowing of discharge electrodes. For example, these problems may be accentuated with the larger electro-precipitators where for example it may be required to have a discharge electrode assembly 40 feet or more in height.

It is an object of the invention to provide an improved electro-precipitator electrode support structure.

The invention also provides an electro-precipitator discharge electrode support structure which comprises an upper portion comprising a plurality of vertical elongated support members which extend upwardly from a central region of the structure, a lower portion also comprising a plurality of vertical elongated support members which are non integral with the support members of the upper portion and extend downwardly from the central region, and a braced cage which at the central region connects the support members of the upper portion to the support members of the lower portion.

The invention also provides an electro-precipitator comprising a casing, a plurality of collector electrodes mounted in the casing and a plurality of discharge electrodes located between adjacent collector electrodes and supported in a structure according to the invention.

There now follows a description, to be read with reference to the accompanying drawings, of an electroprecipitator embodying the invention. This description is given by way of example of the invention only and not by way of limitation thereof.

In the drawings:

FIG. 1 shows a broken side view of parts of the electro-precipitator embodying the invention;

FIG. 2 shows a section generally on the line II-II of FIG. I with certain parts omitted;

FIG. 3 shows an enlarged view of parts shown in FIG.

FIG. 4 shows a plan view corresponding to FIG. 3; FIG. 5 shows another enlarged view of parts shown in FIG. 1;

FIG. 6 shows a view, corresponding to FIG. 3, of a modification;

FIG. 7 shows a view, corresponding to FIG. ,5, of the modification;

' FIG. 8 shows a side view of parts of a second electroprecipitator embodying the invention;

FIG. 9 shows to the left of the center line CL a broken sectional view generally on the line IX-IX of FIG. 8, and shows to the right of the center line CL a broken sectional view generally on the line IXaIXa of FIG. 8.

FIG. 10 shows an enlarged view of parts shown in FIG. 9; and

FIG. 11 shows a sectional end view of parts shown in FIG. 10.

The precipitator embodying the invention comprises a large casing 12 adapted to provide a treatment chamber 14 for the precipitation of dust from gas flowing through the chamber 14 from an inlet 16 to an outlet 18. In the operation of the precipitator, dust-laden gas to be treated flows in a generally horizontal direction through the treatment chamber 14 (the direction of the arrow X in Figure 1).

An electrode bank 24 is provided in the chamber 14.

The electrode bank 24 comprises a plurality of vertical dust collector electrode plate members 28 and a plurality of elongated vertical discharge electrodes 32. A planar row of discharge electrodes 32 is provided midway between each pair of adjacent plate members 28. In the operation of the precipitator the plate members 28 are earthed and the discharge electrodes 32 are charged to a high potential; as a result dust is precipitated from the gas and collects on the plate members 28. The precipitator also comprises rapping mechanism (not shown) of known type adapted to dislodge the collected dust from the plate members 28.

Each plate member 28 is of a previously proposed type comprising a plurality of channel portions 36, which provide troughs to either side of the member 28, the troughs being open against the direction of gas flow; reference may be made to UK. Pat. specification No. 1,172,854 for a more detailed description of the plate members.

Each plate member 28 is suspended from a beam 40 which is resiliently mounted in the casing 12 on girders 43. A horizontal tube 39 is secured to a lower end portion of the plate member 28 and extends into units 41 which are secured to the casing 12 and assist in locating the plate member 28.

Each discharge electrode 32 comprises a central vertical support mast tube 42 (FIGS. 1 to 3) of uniform circular cross-section; secured in the tube 42 are a plurality of horizontal co-extensive uniformly spaced cross members 46 which extend in the direction of gas flow; the cross members 46 support four parallel long vertical twisted discharge wires 48a which are spaced from the tube 42, two on either side thereof.

The electrode bank 24comprises a discharge electrode support structure 45 comprising a first, upper end portion 60 comprising a plurality of vertical elongated support members provided by the tubes 42 of upper discharge electrodes 32 and extending upwardly from a central region of the structure; and a second, lower end portion 62 also comprising a plurality of vertical elongated support members provided by the tubes 42 of lower discharge electrodes 32 and extending downwardly from the central region. The tubes 42 of the upper end portion 60 are non-integral with and axially aligned with the tubes 42 of the lower end portion 62. The structure also comprises at the central region thereof a rectangular braced cage 64 intermediate the

end portions

60, 62 which connects the tubes 42 of the end portion 60 to the tubes 42 of the end portion 62 and is adapted to minimize relative movement of the first and second end portions when the structure is in use. The cage 64 itself is adapted to provide a discharge electrode function so that there is no lack of continuity in this respect in the region of the cage 64.

The structure 45 also comprises a first, upper, framework 46 and a second, lower framework 54; the

frameworks

46, 54 support respectively the upper end 7 portions of the upper discharge electrodes 32, and the lower end portions of the lower discharge electrodes 32. The upper discharge electrodes 32 are suspended from the framework 46 which is itself suspended from a roof portion 48 of the casing 12. The framework 46 comprises a plurality of horizontal girders 50 extending in the direction of gas flow; to each girder 50 are secured the tubes 42 of the upper electrodes 32 of one row. The girders 50 are connected by two horizontal girders 52 which extend at right angles to the girders 50 and are braced by girders 53. The two girders 52 are resiliently suspended from the roof portion 48 by two support assemblies 55 (only one of which is shown) of generally known type. Each assembly 55 comprises a girder unit 57 above the two girders 52 to which the girders 52 are resiliently secured by bolts 59, corresponding nuts and springs 63. The girder unit 57 is secured to two vertical members 65 which are secured in insulator assemblies 67 mounted in the roof portion 48. Rapping mechanism (not shown) of known type is provided and is arranged to dislodge any dust collecting on the discharge electrodes 32.

The framework 54 comprises a plurality-of horizontal girders 56 extending in the direction of gas flow; to each girder 56 are secured tubes 42 of the lower electrodes 32 of one row. The girders 56 of the framework 54 are connected by two horizontal tubes 56a which extend at right angles to the girders 56.

The lower end portion of each upper electrode 32 is secured to a horizontal plate 70 (FIGS. 3-5) which is bolted to the cage 64 by nuts and bolts 72. The tube 42 of the electrode 32 is secured to the plate 70 by a bracket 74 which is secured in a slot 76 in the tube 42 and is welded to the plate 70. The four wires 48a of the electrode 32 are secured in the plate 70 by welding.

The cage 64 comprises a plurality of upper horizontal rectangular tubes 76 which extend in the direction of gas flow and to each of which the upper electrodes 32 of one row are secured by the plates 70 there being one tube 76 to each row or upper electrodes 32.

The cage 64 also comprises a plurality of lower horizontal rectangular tubes 78 which are aligned with the tubes 76 and to which the upper end parts of each lower electrode 32 are secured in the same way as the upper electrodes 32 are secured to the tubes 76.

Each outer end portion of each tube 76 is secured to a horizontal strut 80 of flat cross-section; the struts 80 extend at right angles to the tubes 76. Similarly the outer end portions of the tubes 78 are secured to horizontal struts 82 of flat cross-section which extend at right angles to the tubes 78 and are aligned with the struts 80. Each pair of aligned struts 80, 82 are connected by two inclined struts 84 of flat cross-section. Each strut 84 extends from the axis of an outermost tube 76 downwardly to the axis of an inner tube 78 at an angle of about 45. The struts 84 are secured by bolts 86 each of which extends through a strut 84, a

strut

80 or 82 and is screwed into a captive nut (not shown) in the

appropriate tube

76 or 78. Each

tube

76, 78 is secured to the

struts

80, 82 respectively by such bolts and captive nuts.

Vertical tubes 88 extend between each aligned pair of aligned

tubes

76, 78 being secured to said

tubes

76, 78 by welding; each tube 88 is axially aligned with an axially aligned pair of upper and lower tubes 42 and corresponds thereto in cross-section; there is a tube 88 axially aligned with each axially aligned pair of upper and lower tubes 42.

The discharge electrode function of the cage 64 is provided by vertical twisted wires 90 which extend between each pair of aligned

tubes

76, 78 being secured in said tubes by welding; each wire 90 is axially aligned with an axially aligned pair of upper and lower wires 48a; there is a wire 90 axially aligned with each axially aligned pair of upper and lower wires 48a.

it will be realized that in the operation of the precipitator, the discharge electrodes 32 and the cage 64 are at the same electrical potential.

It will also be realized that the structure 45 is adapted to minimize relative swinging movement of the

frameworks

46, 54 transversely of the structure in the direction of the arrow X and at right angles thereto, and is also adapted to minimize relative torsional movement of the

frameworks

46, 54 transversely of the structure.

The distance between the

frameworks

46, 54 is long, for example about 40 feet, the height of the cage being for example about 5 feet.

The modified electro-precipitator embodying the invention illustrated in FIGS. 6 and 7 resembles that described with reference to FIGS. 1 to S in many respects and is described in so far as it differs therefrom.

In the modified electro-precipitator a plate corresponding to a plate 70 is directly welded to an upper tube 142 corresponding to tube 42 and the plate 170 is secured to a tube 176 corresponding to a tube 76 by a pin 200 which is secured in the tube 142 by welding and extends through the plate 170 and the tube. 176. The pin 200 is secured in the tube 176 by a bent key 202 which is secured in a corresponding transverse slot in the pin 200 and engages a washer 204 surrounding the pin 200 and engaging a lower surface of the tube 176. Locating rivets 206 extend from the plate 170 into corresponding sockets in the tube 176.

Lower tubes 142 are similarly secured to lower tubes 178 corresponding to the tubes 78.

Tubes 188 corresponding to the tubes 88 are not aligned with the upper and lower tubes 142 but each tube 142 has a pair of tubes 188 evenly spaced to either side thereof.

in a further modification (not shown) the plate 170 is secured to the tube 142 by a bolt which extends through the tube 176 and the plate 170 and is screwed into a captive nut in the tube 142.

The second precipitator embodying the invention resembles the precipitator described with reference to FIGS. 1 to 5 in many respects and is described in so far as it differs therefrom.

In the second precipitator embodying the invention the support structure 45 is replaced by a support structure 345.

The electro-precipitator comprises a plurality of discharge electrodes 332 corresponding in many respects to the discharge electrodes 32.

Each discharge electrode 332 comprises a central vertical support mast tube 342 of uniform circular cross-section; secured in the tube 342 are a plurality of horizontal co-extensive uniformly spaced cross members 346 which extend in the direction of gas flow; the cross members 346 support four long vertical twisted wires 348a which are spaced from the tube 342.

The discharge electrode support structure 345 comprises a first, upper portion 360 comprising a plurality of elongated support members provided by the tubes 342 of upper discharge electrodes 332, and a second, lower portion 362 also comprising a plurality of elon gated support members provided by the tubes 342 of lower discharge electrodes 332. The tubes 342 of the lower portion 362 are arranged in alternating

rows

362a, 362b (FIG. 8). The tubes 342 of each row 362a extend upwardly to terminate at the lower end of a central region of the support structure 345 (FIGS. 8 and 9), while the tubes 342 of each row 362b extend upwardly to terminate at the upper end of the central region. The tubes 342 of the upper portion 360 are similarly arranged in alternating

rows

360a, 360b axially aligned respectively with

rows

362a, 362b; the tubes 342 of the rows 360a extend downwardly to terminate at the lower end of the central region of the support structure 345, while the tubes 342 of the rows 360b extend downwardly to terminate at the upper end of the central region. It will be realized that the tubes 342 of the upper portion 360 are non-integral with the tubes 342 of the lower portion 362. The structure also comprises a braced cage 364 which at the central region of the structure connects the tubes 342 of the portion 360 to the tubes 342 of the portion 362, the

rows

360a, 360b being connected to the

rows

362a, 362b respectively. The cage 364 is adapted to minimize relative movement of the first and

second portions

360, 362 when the structure is in use.

The lower end portion of each electrode 332 of the rows 360b is secured to a half-tube 370 (FIGS. 10 and 11) of angular cross-section which is bolted to the cage 364 by nuts and bolts 372. The tubes 342 of the electrode 332 is welded to the half tube 370 and the four wires 348a of the electrode 332 are secured to the half tube 370 via welded sockets 370a. The upper end portion of the aligned electrode 332 of the appropriate row 362b is similarly secured to a half tube 370 which is bolted to the cage 364 by the same nuts and bolts 372 as the first mentioned half tube 370.

The cage 364 comprises a plurality of upper horizontal tubes 376 which extend in the direction of gas flow and to each of which the electrodes 332 of one row 360b and the corresponding electrodes 332 of one row 362b are secured by the half tubes 370 there being one tube 376 to each

row

360b and 362b. Each bolt 372 passes through upper and lower half tubes 370 and through the appropriate tube 376 which is fitted within the half tube 370.

The cage 364 also comprises a plurality of lower horizontal tubes 378 which when viewed from above alternate with the tubes 376 and to which the upper end portions of the electrodes 332 of the rows 362a and the lower end portions of the electrodes 332 of the rows 360a are secured in the same way as the electrodes 332 of the

rows

360b, 362b are secured to the tubes 376.

Each outer end portion of each tube 376 is secured to a horizontal strut 380 of flat cross-section; the struts 380 extend at right angles to the tubes 376. Similarly the outer end portions of the tubes 378 are secured to horizontal struts 382 of flat cross-section which extend at right angles to the tubes 378 and are aligned with the struts 380. Each pair of aligned

struts

380, 382 are connected by two inclined struts 384 (only one of which is shown in FIG. 8) of flat cross-section. Each strut 384 extends from the axis of an outermost tube 376 downwardly to the axis of an inner tube 378 at an angle of about 45. The struts 384 are secured by bolts 386 each of which extends through a strut 384, a

strut

380 or 382 and is screwed into a captive nut (not shown) in the

appropriate tube

376, or 378. Each

tube

376, 378 is secured to the

struts

380, 382 respectively by such bolts and captive nuts.

In a modification each half tube 370 is of semi-circular cross-section to correspond with the cross-section of the tube 376.

It will be appreciated that other known forms of discharge electrodes may be used instead of the twisted wire-type.

We claim:

1. An electro-precipitator discharge electrode support structure having a central region and said structure comprising a. an upper portion comprising a plurality of vertical elongated support members which extend upwardly from the central region of the structure,

b. a lower portion also comprising a plurality of vertical elongated support members which are non integral with the support members of the upper portion and extend downwardly from the central region, and

c. a braced cage which at the central region connects the support members of the upper portion to the support members of the lower portion.

2. A structure according to claim 1 wherein said braced cage is rectangular and connects the support members of the upper portion of the structure to the support members of the lower portion, the cage comprising i. a plurality of upper and lower horizontal members,

ii. means for securing the support members to the cage,

iii. horizontal struts interconnecting the upper horizontal members said struts extending transversely of said upper horizontal members,

iv. further horizontal struts interconnecting the lower horizontal members said struts extending transversely of said lower horizontal members, and

v. inclined struts connecting the upper horizontal struts to the lower horizontal struts.

3. In a structure according to claim 1, a plurality of discharge electrodes, each discharge electrode comprising a support mast, a plurality of cross members which extend from the support mast, and discharge wires supported by the cross members, the support masts providing said support members of the structure.

4. A structure according to claim 3 wherein each discharge electrode comprises four parallel discharge wires, two on either side of the mast.

5. A structure according to claim 3, comprising a plurality of horizontal half-tubes, means securing an appropriate end portion of the support mast of each electrode to a said horizontal half-tube, means securing the half-tube to the braced cage, and means securing the discharge wires of the electrode to the half-tube.

6. A structure according to claim 1 wherein the support members of the upper portion are provided in a first set of rows the support members of which rows extend downwardly to terminate at an upper end of the central region and a second set of rows which alternate with the first set and the support members of which extend downwardly to terminate at a lower end of the central region; and wherein the support members of the lower portion are provided in a first set of rows longitudinally aligned with the first set of rows of the upper portion and the support members of which rows of the lower portion extend upwardly to terminate at the upper end of the central region, and a second set of rows aligned with the second set of rows of the upper portion, and the support members of which extend upwardly to terminate at the lower end of the central regen.

7. A structure according to claim 1 comprising a plurality of half-tubes, means securing and appropriate end portion of each support member to a said halftube, and means securing the half-tubes to the braced cage.

8. An electro-precipitator comprising a casing, a plurality of collector electrodes mounted in the casing, a plurality of discharge electrodes located between ad- 5 jacent collector electrodes, and a discharge electrode support structure in which the discharge electrodes are supported, said structure having a central region and said structure comprising (a) an upper portion comprising a plurality of vertica] elongated support members which extend upwardly from the central region of the structure,

(b) a lower portion also comprising a plurality of vertical elongated support members which are non integral with the support members of the upper portion and extend downwardly from the central region, and

(c) a rectangular braced cage which at the central region connects the support members of the upper portion to the support members of the lower portion, said braced cage comprising vertically spaced horizontal members and inclined bracing struts.

Claims

1. An electro-precipitator discharge electrode support structure having a central region and said structure comprising a. an upper portion comprising a plurality of vertical elongated support members which extend upwardly from the central region of the structure, b. a lower portion also comprising a plurality of vertical elongated support members which are non integral with the support members of the upper portion and extend downwardly from the central region, and c. a braced cage which at the central region connects the support members of the upper portion to the support members of the lower portion.

2. A structure according to claim 1 wherein said braced cage is rectangular and connects the support members of the upper portion of the structure to the support members of the lower portion, the cage comprising i. a plurality of upper and lower horizontal memBers, ii. means for securing the support members to the cage, iii. horizontal struts interconnecting the upper horizontal members said struts extending transversely of said upper horizontal members, iv. further horizontal struts interconnecting the lower horizontal members said struts extending transversely of said lower horizontal members, and v. inclined struts connecting the upper horizontal struts to the lower horizontal struts.

6. A structure according to claim 1 wherein the support members of the upper portion are provided in a first set of rows the support members of which rows extend downwardly to terminate at an upper end of the central region and a second set of rows which alternate with the first set and the support members of which extend downwardly to terminate at a lower end of the central region; and wherein the support members of the lower portion are provided in a first set of rows longitudinally aligned with the first set of rows of the upper portion and the support members of which rows of the lower portion extend upwardly to terminate at the upper end of the central region, and a second set of rows aligned with the second set of rows of the upper portion, and the support members of which extend upwardly to terminate at the lower end of the central region.

7. A structure according to claim 1 comprising a plurality of half-tubes, means securing and appropriate end portion of each support member to a said half-tube, and means securing the half-tubes to the braced cage.

8. An electro-precipitator comprising a casing, a plurality of collector electrodes mounted in the casing, a plurality of discharge electrodes located between adjacent collector electrodes, and a discharge electrode support structure in which the discharge electrodes are supported, said structure having a central region and said structure comprising (a) an upper portion comprising a plurality of vertical elongated support members which extend upwardly from the central region of the structure, (b) a lower portion also comprising a plurality of vertical elongated support members which are non integral with the support members of the upper portion and extend downwardly from the central region, and (c) a rectangular braced cage which at the central region connects the support members of the upper portion to the support members of the lower portion, said braced cage comprising vertically spaced horizontal members and inclined bracing struts.