U.S. patent number 3,660,968 [Application Number 04/875,396] was granted by the patent office on 1972-05-09 for electro-precipitators.
This patent grant is currently assigned to Lodge-Cottrell, Limited. Invention is credited to Robin A. Attfield, John F. Dyla.
United States Patent |
3,660,968 |
Dyla , et al. |
May 9, 1972 |
ELECTRO-PRECIPITATORS
Abstract
An electro-precipitator collector electrode comprises a
plurality of elements each comprising a plate member which
comprises (in profile) a substantially straight central portion and
two bent end portions extending from either end of the central
portion. Each bent end portion engages and is directly and
positively secured to an adjacent bent end portion of an adjacent
element, and each bent end portion comprises a surface which (in
profile) is generally inclined at an angle greater than 90.degree.
to said central portion and engages a corresponding surface of the
said adjacent bent end portion; this angle of the surface
facilitates access of a fastening tool during erection. Adjacent
collector electrodes are braced together along top edges
thereof.
Inventors: |
Dyla; John F. (Birmingham,
EN), Attfield; Robin A. (Great Wyrley,
EN) |
Assignee: |
Lodge-Cottrell, Limited
(Birmingham, EN)
|
Family
ID: |
10472157 |
Appl.
No.: |
04/875,396 |
Filed: |
November 10, 1969 |
Foreign Application Priority Data
|
|
|
|
|
Nov 19, 1968 [GB] |
|
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54,816/68 |
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Current U.S.
Class: |
96/71 |
Current CPC
Class: |
B03C
3/40 (20130101); B03C 3/86 (20130101); B03C
3/47 (20130101) |
Current International
Class: |
B03C
3/40 (20060101); B03C 3/86 (20060101); B03C
3/34 (20060101); B03C 3/45 (20060101); B03C
3/47 (20060101); B03c 003/00 () |
Field of
Search: |
;55/148,112,130,140,141,143,145,150,151,148,152,153,154,156 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
922,543 |
|
Apr 1963 |
|
GB |
|
937,925 |
|
Sep 1963 |
|
GB |
|
122,534 |
|
Jan 1919 |
|
GB |
|
926,128 |
|
May 1963 |
|
GB |
|
963,109 |
|
Jul 1964 |
|
GB |
|
1,099,342 |
|
Jan 1968 |
|
GB |
|
Other References
German Printed Application (E) No. 1158043 printed November 28,
1963, (1 sht dwg, 2 pp spec).
|
Primary Examiner: Talbert, Jr.; Dennis E.
Claims
We claim:
1. In a Cottrell electro-precipitator, a collector electrode
assembly comprising a plurality of spaced collector electrodes and
bracing means bracing the electrodes together, each electrode
comprising
a plurality of elements, each comprising a plate member which
comprises, in profile, a substantially straight central portion and
two bent end portions extending from either end of the central
portion, each bent end portion engaging an adjacent bent end
portion of an adjacent element, and each bent end portion
comprising a surface which, in profile, is generally inclined at an
angle greater than 90.degree. to said central portion and engages a
corresponding surface of the said adjacent bent end portion,
and
means for directly and positively securing the adjacent bent end
portions together;
the assembly also comprising a plurality of collector electrode
support members, and means for securing each electrode of said
assembly to a said collector electrode support member from which
the electrode extends downwardly when the assembly is in use, and
wherein the bracing means connects together adjacent support
members of different collector electrodes of said assembly;
said bracing means comprising a tubular assembly which extends
between two adjacent support members and comprises two outer
tubular members, one secured to each support member and said two
tubular members being opposite and aligned, a further, inner
tubular member aligned with and extending between said two aligned
tubular members and a fastener extending through the three aligned
tubular members to secure said tubular members together.
2. An electrode assembly according to claim 1 wherein in each
collector electrode each said surface is flat and said surfaces are
in superficial engagement.
3. An electrode assembly according to claim 1, wherein in each
collector electrode each bent end portion comprises
a straight central part providing said surface and extending across
the plane of the straight central portion of the plate member,
a straight part which is inclined to the straight central portion
of the plate member and leads therefrom to the central part,
and
a hook-shaped end part which leads from the central part in a
direction generally away from the adjacent bent end portion.
4. An electrode assembly according to claim 3 wherein in each
collector electrode the bent end portions define pockets adapted to
face the direction of gas flow.
5. An electrode assembly according to claim 3 wherein in said
collector electrode each surface is inclined at an angle of about
120.degree. to the central portion.
6. An electrode assembly according to claim 1 wherein in each
collector electrode each bent end portion comprises
a straight central part providing said surface and extending across
the plane of the straight central portion of the plate member,
a straight part which is inclined to the straight central portion
of the plate member and leads therefrom,
a curved part which leads from said last-mentioned straight part to
said central part, and
a curved end part which leads from the central part generally along
the contour of the adjacent bent end portion.
7. An electrode assembly according to claim 6 wherein in said
collector electrode each surface is inclined at an angle of about
105.degree. to the central portion.
8. An electrode assembly according to claim 1 wherein in each
collector electrode the securing means comprises load-bearing
non-reversible fasteners extending through said surfaces of the
bent end portions.
9. An electrode assembly according to claim 1 wherein in each
collector electrode each surface is inclined at an angle between
95.degree. and 175.degree. to the central portion.
10. A collector electrode assembly according to claim 1 comprising
two,only, collector electrodes.
11. An electro-precipitator comprising a casing, a plurality of
spaced collector electrode assemblies, a plurality of discharge
electrodes located in spaces between the collector electrodes of
the assemblies, and means for supporting the collector electrodes
and discharge electrodes in the casing each collector electrode
assembly comprising (a) two upper horizontally elongated tubular
support members (b) two lower horizontally elongated support
members (c) two vertical generally planar parallel collector
electrodes each of which is secured to a said upper support member
from which the collector electrode extends downwardly and which
electrode is also secured to a said lower support member from which
the collector electrode extends upwardly, and (d) bracing means
connecting together the support members of said assembly said
bracing means comprising a tubular assembly which extends between
the support members at right angles thereto and comprises two
horizontal tubular members one secured in each support member said
two tubular members being opposite and aligned, a further tubular
member aligned with and extending between said two aligned tubular
members and a fastener extending through the three aligned tubular
members to secure said tubular members together; each collector
electrode comprising (i) a plurality of elements each comprising a
plate member which comprises (in profile) a substantially straight
central portion and two bent end portions extending from either end
of the central portion and each bent end portion engaging an
adjacent bent end portion of an adjacent element, and each bent end
portion comprising a surface which (in profile) is generally
inclined at an angle greater than 90.degree. to said central
portion, whereby access of fastening means is facilitated, and
engages a corresponding surface of the said adjacent bent end
portion and (ii) means for directly and positively securing the
adjacent bent end portions together; each collector electrode
together with its upper and lower support members providing a
stressed skin-deep beam construction.
Description
This invention is concerned with improvements in or relating to
Cottrell electro-precipitators suitable for use in removing dust
and the like from gases.
A Cottrell electro-precipitator is a well known type of
electro-precipitator which generally comprises a casing, a
plurality of spaced collector electrodes in the casing, a plurality
of discharge electrodes located in the spaces between the collector
electrodes, and means for supporting the collector electrodes and
discharge electrodes in the casing. The discharge electrodes are
charged to a high potential and the collector electrodes are
grounded; corona discharge takes place between the discharge
electrodes and the collector electrodes resulting in dust and the
like being collected in the collector electrodes. For a full
discussion of Cottrell electro-precipitators reference may be made
to "Chemical Engineers Handbook" by John H. Perry.
In such electro-precipitators design of the collector electrodes on
which the dust is precipitated is important.
It is an object of the invention to provide an improved
electro-precipitator collector electrode element.
It is another object of the invention to provide an improved
electro-precipitator collector electrode.
It is another object of the invention to provide an improved
electro-precipitator collector electrode assembly comprising a
plurality of collector electrodes braced together.
It is another object of the invention to provide an improved
electro-precipitator.
The invention provides in a Cottrell electro-precipitator a
collector electrode assembly comprising a plurality of spaced
collector electrodes and bracing means bracing the electrodes
together each electrode comprising a plurality of elements each
comprising a plate member which comprises (in profile) a
substantially straight central portion and two bent end portions
extending from either end of the central portion and each bent end
portion engaging and being directly and positively secured to an
adjacent bent end portion of an adjacent element, and each bent end
portion comprising a surface which (in profile) is generally
inclined at an angle greater than 90.degree. to said central
portion and engages a corresponding surface of the said adjacent
bent end portion.
Said surface is preferably flat but it will be realized that it may
be curved somewhat.
The adjacent bent end portions may be secured together by, for
example, a load-bearing non-reversible fastener.
By the expression "non-reversible fastener" we mean a fastener
which once fastened is devoid of any normal unfastening function.
Examples of non-reversible fasteners include various forms of
rivets, but nuts and bolts would not be included.
The electrode elements are preferably shaped for ease of stacking
for storage and transport.
The invention also provides an electro-precipitator comprising a
casing, a plurality of spaced collector electrode assemblies, and a
plurality of discharge electrodes located in spaces between the
collector electrodes of the assemblies, each collector electrode
assembly comprising (a) two vertical generally planar parallel
collector electrodes each of which is secured to a horizontally
elongated tubular support member mounted in the casing and from
which the collector electrode extends downwardly, and which
electrode is also secured to a lower support member from which the
collector electrode extends upwardly, and (b) bracing means
connecting together the support members of said assembly said
bracing means comprising a tubular assembly which extends between
the support members at right angles thereto and comprises two
horizontal tubular members one secured in each support member said
two tubular members being opposite and aligned, a further tubular
member aligned with and extending between said two aligned tubular
members and a fastener extending through the three aligned tubular
members to secure said tubular members together; each collector
electrode comprising a plurality of elements each comprising a
plate member which comprises (in profile) a substantially straight
central portion and two bent end portions extending from either end
of the central portion and each bent end portion engaging and being
directly and positively secured to an adjacent bent end portion of
an adjacent element, and each bent end portion comprising a surface
which (in profile) is generally inclined at an angle greater than
90.degree. to said central portion, whereby access of fastening
means is facilitated, and engages a corresponding surface of the
said adjacent bent end portion; each collector electrode together
with its upper and lower support members providing a stressed
skin-deep beam construction.
There now follows a description, to be read with reference to the
accompanying drawings, of an electro-precipitator embodying the
invention. This description is given by way of example of the
invention only and not by way of limitation thereof.
In the accompanying drawings:
FIG. 1 shows a plan view of parts of an electro-precipitator
embodying the invention;
FIG. 2 shows an enlarged plan view of parts shown in FIG. 1;
FIG. 3 shows a stack of electrode elements;
FIG. 4 shows a view corresponding to FIG. 2 of parts of a modified
electro-precipitator embodying the invention;
FIG. 5 shows a stack of modified electrode elements;
FIG. 6 shows a plan view of parts of a collector electrode of
another modified electro-precipitator embodying the invention;
FIG. 7 shows a view corresponding to FIG. 6 of parts of a collector
electrode of a further modified electro-precipitator embodying the
invention;
FIG. 8 shows a diagrammatic view of an electro-precipitator;
FIG. 9 is a sectional end view of parts of an electro-precipitator
collector electrode assembly; and
FIG. 10 is a top plan view showing parts shown in FIG. 9.
The electro-precipitator embodying the invention comprises (FIG. 8)
a casing 2, a plurality of spaced collector electrode assemblies 4
(only one of which is shown) independently supported in the casing
2, and a plurality of discharge electrodes 14 of known type
supported in the casing 2 and located in the spaces between the
collector electrodes (see FIG. 1). The precipitator comprises a gas
inlet 3 and a gas outlet 5, through which dust-laden gas to be
cleaned is passed in the direction of the arrows X. The casing has
a roof 7 and an outlet opening 9 for precipitated dust. The
precipitator also comprises means (not shown) for supplying high
potential to the discharge electrodes 14.
Each collector electrode assembly 4 comprises two (FIG. 9) spaced
vertical generally planar parallel collector electrodes 12 which
are braced together. Each collector electrode 12 is secured to and
extends downwardly from a horizontally elongated tubular support
member 14a (FIGS. 9 and 10) of vertically elongated, rectangular
cross-section; each support member 14a is mounted in the casing of
the electro-precipitator by brackets 10.
In the operation of the apparatus the collector electrodes 12 are
earthed and the discharge electrodes 14 are charged to a high
potential; as a result dust is precipitated from the gas and
collects on the collector electrodes 12.
The discharge electrodes 14 are arranged in generally planar rows
(only one of which is shown in FIG. 1) parallel to the direction of
gas flow which is indicated by the arrow A in FIG. 1, the rows
alternating with the collector electrodes 12.
Each collector electrode 12 (FIGS. 1 and 2) comprises a plurality
of electrode elements 16, 18 and elements 16 alternating with the
elements 18. Each element 16 has the same plan view profile and
comprises a cold rolled light gauge metal vertically elongated
plate member 20 (FIG. 2) which comprises (in plan view profile) a
long substantially straight central portion 22 and two short bent
end portions 24, 26 integral with the portion 22 and extending from
either end thereof; the end portion 24 is leading with respect to
the gas flow and the end portion 26 trailing; the end portions 24,
26 lead off from the same side of the central portion 22; the
central portion 22 comprises a small curved portion 23 for
rigidity. Each element 18 also has the same plan view profile,
which is complementary to that of the elements 16, and comprises a
light gauge metal vertically elongated plate member 28 which
comprises (in plan view profile) a long substantially straight
central portion 30 and two short bent end portions 32, 34 integral
with the portion 30 and extending from either end thereof; the end
portion 32 is leading with respect to the gas flow and the end
portion 34 trailing; the end portions 32, 34 lead off from the
opposite side of the central portion 28 to the end portions 24, 26.
The central portions 22, 30 of each electrode element 16, 18 are
collinear, and adjacent end portions 24, 34 and 26, 32 engage and
are secured together directly and positively.
Each pair of adjacent end portions 24, 34 and 26, 32 are secured
together directly and positively by a rivet 33 which extends
through the adjacent end portions. The rivet 33 is for example, a
load-bearing non-reversible rivet of the kind known as an "Avdel"
rivet; alternatively the rivet 33 is replaced by a conventional
load-bearing bolt and nut or the securing together may be carried
out by welding. Each end portion 24, 26 comprises a straight
central portion 35 providing an outer flat surface 31 which is
inclined at an angle .theta. greater than 90.degree. to the central
portion 22 and is in superficial engagement with a corresponding
outer flat surface 36 of a straight central portion 37 of the
adjacent end portion 34, 32; the appropriate rivet 33 passes
through the central portions 35, 37.
Each end portion 24, 26 comprises (in profile) a straight portion
38 which is inclined to the central portion 22 and leads therefrom
to the central portion 35 which extends at right angles from the
portion 38 across the plane of the central portion 22. Each end
portion 24, 26 also comprises a hook-shaped end portion 40 which
leads from the central portion 35 in a direction generally away
from the adjacent bent end portion 34, 32. The end portions 34, 32
are of complementary profile to the end portions 24, 26.
The end portions 26, 34 define pockets which face the direction of
gas flow in the operation of the electro-precipitator and serve to
facilitate collection of precipitated dust.
It will be realized that the electrode elements 16, 18 are shaped
for ease of stacking for storage and transport prior to erection. A
stack of elements 16, 18 is shown in FIG. 3 which illustrates the
manner of stacking in which the end portions 24, 34 are received
within the end portions 32, 26 respectively.
The modified form of electro-precipitator parts of which are shown
in FIG. 4 resembles the electro-precipitator described with
reference to FIGS. 1 and 2 in many respects and is described in so
far as it differs therefrom.
Said modified form comprises elements 116, 118 corresponding
generally to the elements 16, 18. Each element 116 comprises end
portions 124, 126 corresponding to the end portions 24, 26 and end
portions 132, 134 corresponding to the end portions 32, 34.
Each end portion 124, 126 comprises a straight central portion 135
providing an inner flat surface 131 which is in superficial
engagement with a corresponding inner flat surface 136 of a
straight central portion 137 of the adjacent end portion 134,
132.
Each end portion 124, 126 comprises (in profile) a straight portion
138 which is inclined to a central portion 122 of the element 116
and leads from the central portion 122 to a curved portion 150 of
said end portion 124, 126 which curved portion 150 leads from the
portion 138 to the central portion 135. Each end portion 124, 126
also comprises a curved end portion 140 which leads from the
central portion 135 generally along the contour of the adjacent end
portion 134, 132 so that the end portion 140 is in superficial
engagement with an inner surface of a curved portion 152 of the
adjacent end portion 134, 132 which portion 152 corresponds to the
portion 150 of each end portion 124, 126; thus the portion 152
shields the portion 140 to minimize the risk of flashover from a
discharge electrode to the end of the portion 140.
Again it will be realized that the elements 116, 118 are easily
stacked and a stack of elements 116, 118 is illustrated in FIG. 5,
the stacked elements 116, 118 being in nested relationship.
FIG. 6 shows parts of a modified collector electrode corresponding
in many respects to the collector electrodes 16; in the modified
electrode end portions 224, 226 corresponding to the end portions
24, 26 lead off from opposite sides of a central portion 222,
corresponding to the central portion 22, instead of from the same
side thereof. End portions 232, 234 corresponding to the end
portions 32, 34 similarly lead off from opposite sides.
FIG. 7 shows parts of a modified collector electrode, corresponding
in many respects to the collector electrodes 116; in this modified
electrode end portions 324, 326 corresponding to the end portions
124, 126 lead off from opposite sides in a similar fashion to the
end portions 224, 226. End portions 332, 334 corresponding to the
end portions 132, 134 similarly lead off from opposite sides.
It will be realized that the angle and general arrangements of the
central portions 35, 37 and corresponding parts shown in FIGS. 4 to
7, facilitate access of fastening means during erection; for
example, access is facilitated of the rivets themselves and of a
fastening tool to fasten the rivets, or of other fasteners and
other kinds of fastening tools as appropriate.
The central portions 35, 37 and corresponding parts shown in FIG. 6
are preferably inclined at an angle (.theta.) between 95.degree.
and 175.degree. (more preferably between 95.degree. and
150.degree.) to the central portion 22, for example about
120.degree.. The central portions 135, 137 and corresponding parts
shown in FIG. 7 are preferably at an angle between 95.degree. and
175.degree. (more preferably between 95.degree. and 150.degree.) to
the central portion 122, for example about 105.degree..
The collector electrode assembly shown in FIGS. 9 and 10 comprises
bracing means connecting together the support members 14a of the
assembly to brace the collector electrodes of the assembly
together. The bracing means comprises a tubular assembly 416
extending between the support members 14a at right angles thereto
and being centrally located intermediate end portions of the
tubular members 14a. The bracing means also comprises girder
members 418 extending between the support members 14a and located
adjacent opposite end portions thereof.
The tubular assembly 416 comprises a tubular member 420 of circular
cross-section extending transversely through and secured in one
member 14a and a tubular member 422 also of circular cross-section
extending transversely through and secured in the other member 14a;
each member 420,422 is flush with the outside of its member 14a and
the member 420 is opposite to and aligned with the member 422; the
assembly 416 also comprises a tubular member 424 which is aligned
with and extends between the tubular members 420, 422; the
appropriate collector electrode 12 is connected to the tubular
member 14a by bolting (or riveting--not shown) to a series of
straps 500 which are welded to the tubular member 14a and bolted
(or riveted by Avdel rivets not shown) to the central portions 22
of the collector electrode elements 16, 18 the straps 500 being
horizontally spaced along the collector electrode 12 (FIG. 8) with
a pair of straps 500 on either side of each pair of adjacent bent
end portions 24, 34; 26, 32. The tubular assembly also comprises a
rod 428 which extends through the channel members 426, the tubular
members 420, 422 and the tubular member 424 and is threaded at
either end, with nuts 430 screwed thereonto to secure the tubular
members 420, 422, 424 together, thereby connecting the members 14a
together. Each collector electrode 12 is also secured to a bottom
bar 431 (FIG. 8) from which the electrode 12 extends upwardly. The
electrode 12 is connected to the bar 431 by straps 502 similar to
the straps 500, the straps 502 being welded to the bar 431 and
bolted (or riveted by "Avdel rivets" not shown) to the central
portions 22 of the collector electrode elements 16, 18 the straps
502 being horizontally spaced in a corresponding manner to the
straps 500 (FIG. 7) from which the electrode 12 extends upwardly.
The bottom bars 431 are not braced together but are restrained
against excessive movement by means not shown. Each collector
electrode 12 together with its upper support member 14a and its
bottom bar 431 provides a stressed skin-deep beam construction. In
a modification the straps 500 are replaced by straps (not shown)
which extend around the cross-section of the tubular member 14a,
being secured therearound by bolts and nuts or "Avdel" rivets which
also secure the collector electrode to the straps.
The girder members 418 are bolted (or riveted by "Avdel" rivets not
shown) to the tubular members 14a and one girder member 418
comprises an upstanding rapping anvil 440 arranged to receive
rapping blows by rapping mechanism (not shown) in the operation of
the electro-precipitator to dislodge precipitated dust from the
electrodes 12 of the assembly.
* * * * *