Note: Descriptions are shown in the official language in which they were submitted.
PR [()R l~RT
~n e~ample o~ some o~ the patent6 in tne prlor art
are the foLlowing Unlted States patents:
2,937,709
3,053,029
3,7~2,681
3,785,125
3,856,476
BACKGROUND OF THE INVENTION
The aforementioned prior art patents disclose generally
annular in cross section concentrically spaced wet wall collector
electrodes with discharge electrodes disposed between the spaced
apart wet wall electrodes. The discharge electrodes of the
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; prior art have generally been composed of arrays of rods vertically
suspended between the adJacent wet walls of the collector elec-
trodes and many of these discharge electrode rodæ have been
generally circular in cross section and generally axially parallel
to the annular in cross section cylindrical structures of the
wet wall collector electrodes.~ With such discharge electrode
structure of the prior art, it has been difficult to obtain the
desired corona field density in various areas of the passages
between the collector walls and around the discharge electrodes.
With a group of suspended discharge electrode rods, it has been
difficult to vary the corona field density as for example, the
density of the corona field from one end of the rods to the
opposite end thereof such as may be desirable in relation to the
flow direction of particle laden air or gases which have hereto-
` fore been directed around such rods in areas between wet wall
surfaces of collector electrodes. Additionally, the inætallation
and maintenance of large arrays of individually suspended rods
./ has been costly in installation and maintenance labor.
Furthermore, the aerodynamics related to the flow of
gases longitudinally of rod like discharge electrodes has not ;~; ;
provided an optimum correlation between electrostatic charging
- of particles and mechanical direction of particles in the gas
by means of aerodynamically functional features of the discharge ' ~-
electrode structures bf the prior art.
SUMMARY OF THE INVENTION
The invention relates to an electrode means for wet wall
electrostatic precipitators including a discharge electrode and
also its relationship to wet wall collector electrodes; more
particularly the invention relates to a screen like or foraminous
i 30 structure of the discharge electrode means of either annular in
.' : .:
' cross section cylindrical form or flat configuration. The
invention specifically relates to a screen like or foraminous
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1~76~8
structure oE the discharge electrode means wherein either screen
or perforate structures are provided with point structures extending
outward to provide points of electrical discharge for creating
the well known corona effect Eor ionically charging particles of
material passing between the electrodes so as to cause the
particles to be attracted to the wet wall surfaces of collector
electrodes. The preferred structure of the discharge electrode
means of the invention comprises a hollow cylindrical annular
in cross section electrode structure having screen like or
foraminous wall means provided with discharge points extending
from opposite sides thereof. The discharge electrode is pre-
ferably made of Titanium although it may be made of stainless
steel or the like. However, Titanium has been discovered to be
considerably more durable in an electrostatic precipitator
handling corrosive gases.
In the screen like structure of the discharge electrode
of the invention, screen like material such as expanded metal
' has been found to perform extremely well and have substantial
rigidity so as to maintain accurate spacing thereof relative
to wet wall surfaces of adjacent collector electrodes.
Additionally, the screen like structure of expanded
metal has been found to have particularly good performance
characteristics in that the bars of the screen like structure
are generally rectangular in cross section and are formed by
shearing processes which leave very sharp corners forming points
~ for electrical discharge to provide for the well known corona
; effect.
Additionally, the generally diamond shaped mesh of
the expanded metal comprises integral interconnecting bars,
some of which are sheared to provide terminal ends of the bars
~ and each terminal end being substantially rectangularin cross sec-
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1~)764~8
tion and having four sharpcorners, all of which provide points for
the emissions of electrical charges to provide for the desired
corona effect. The clipping of the bars may be varied so as
to provide more or less of the terminal ends of the bars to there-
by predetermine the concentration of points and the related corona
field density provided by discharge from these points.
The general cross section of the screen like means
provided by expanded metal is undulating and has a substantial ~ .
section modulus quite greater than the sheet from which the
expanded metal is formed. This extended section or structure
when wrapped into a circular in cross section cylinder provides
a very rigid cylinder and one which may be accurately spaced
relative to adjacent collector electrode walls. It will be under-
stood that the disposition of the expanded metal in a hollow
cylindrical circular in cross section form~ due to the curvature
thereof, provides a very rigid structure with a nominal amount -~
of material and weight.
The foregoing cylindrical structure is suspended from -
suspension arms and hangs generally vertical with the central
axis of the circular in cross section structure in a substantially
vertical position with related hollow cylindrical collector
electrodes in the same disposition and concentrically spaced
relative thereto such that the discharge electrode i5 disposed
between a pair of concentric wet wall surfaces of the collector
electrodes. The specific structure of the discharge electrode `
hauing screen like or foraminous structure employs a circular
frame element near the lower portion and another circular frame
element near the upper portion to which suspension rods are
attached and which are supported on candelabra arms above the -~
discharge and collector electrodes of the invention.
The use of the discharge electrode means having points
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lQ76~88
.:
on opposite sides is such that the concentration of these points
may be varied in such a manner that the electrical discharge from
the discharge electrode may afford a very high corona field
density near the inlet of passages between the collector
electrodes wherein air laden with foreign matter flows and is
ionically charged so as to be driven or attracted to the wet wall
surfaces of the collector electrodes.
The discharge electrode means of the invention also
provides an aerodynamic effect which causes angular departure
10 of the fluids flowing adjacent to the discharge electrodes. such
that the angular departure is directed toward the collector
electrodes and thus the aerodynamic effect provided by the dis-
charge electrode means of the invention assists the ionic
function of the corona field to force the particles carried by
: the air flow adjacent the electrodes into contact with the
collector electrodes.
1 Further, the invention comprises a discharge electrode
~' means which is either screen like or foraminous so that the :~
aerodynamic function around the electrodes is e~ualized from a :
pressure standpoint to alleviate the possibility of creating a
pressure differential at opposite sides of the discharge electrode ~
.i and to thereby change the flow characteristics adjacent to respect-
ive collector electrodes at opposite sides of the discharge elect~
rode.
Accordingly, it will be appreciated that the perforate
or screen like structure allows an even pressure or flow distri-
bution to exist at opposite sides of the discharge electrode and
to thereby permit substantially laminar flow of fluids adjacent ~
to the collector electrodes. `
~ 30 Accordingly, it is an object of the present invention
to provide a novel screen like or foraminous discharge elec-trode
.
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1076~L88
means for cooperative functlon with wet wall collector electrodes
of an electrostatic preclpitator.
Another object of the invention is to provide a novel
screen like or foraminous dlscharge electrode having discharge
points on opposite sides thereof which may be varied in concentra~
tion to vary the corona field density in a direction from the
inlet to the outlet of an electrostatic precipitator in which
the discharge electrode is positioned.
Another object of the invention is to provide a novel ~ -
discharge electrode for electrostatic precipitators wherein a
screen like electrode structure is formed of expanded metal or
the like wherein the cross sectional shape of the bars of the
screen like expanded metal are sheared and have rectangular
cross section provided with sharp edges to provide for discharge
points and further to provide such a structure in which some of ;
: the bars are clipped off to provide terminal stub portions which
form discharge points, the stub portions having ends rectangular
- in cross section with four corners, all of which are sharp and
provide ideal electrostatic discharge teFminals.
Another object of the invention is to provide a screen
like discharge electrode for electrostatic precipitators wherein
a screen such as formed from expanded metal has an extended cross ;~ ;
section in proportion to its weight and is relatively rigid ; ,
thereby providing for integrity of the structure in its spaced
relation with adjacent wet wall surfaces of the collector
: electrodes thus maintaining or providing for efficient establish-
`, ment of a corona field and minimizing the possibility of having
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. arcing from the discharge electrode to the collector electrodes. ;
Another object of the invention is to provide a novel
discharge electrode for electrostatic precipitators which is
made of Titanium and which has been found to be very durable and
efficient in an electrostatic precipitator environment.
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Thus, and in accordance with the present teachings,
a discharge electrode for wet wall electrostatic precipitators
is provided. The discharge electrode is of hollow cylindrical
shape and has annular in cross section foraminous screen like
wall structure provided with upper and lower portions. The
screen like wall structure comprises expanded metal which has
interconnecting bars substantially rectangular in cross section
and has corners forming electrostatic discharge points with
some of the bars interconnecting each other at an angle. Ths
bars are provided with stubs formed by clipping away portions
of some of the bars to leave the stubs which have terminal
ends forming electrode discharge points. The wall structure
which is annular in cross section has opposite surfaces and a
pluralityfor discharge points disposed at the opposite surfaces.
The bars of the screen like structure are all integral with each
other and disposed in a group of parallelograms, each
parallelogram having a pair of parallel bars constituting long
sides of a respective parallelogram and also a pair of spaced
apart parallel bars constituting short sides of each parallelo-
gram. The stubs pro~ect at an angle to and in opposite directionsfrom the-intermediate portions of the long side, the stubs being
the discharge points, and the discharge points in the lower
portion being highly concentrated with the concentration
gradually diminishing toward the upper portions.
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11~)76~8~
Another object o~ the invention is to provide a
discharge electrode for electrostatlc precipitators having novel
aerodynamic Eunctions which cooperate with the electrostatic
functions to mechanically move foreign matter in an alr stream
; in addition to the ionic forces in attaining collection of the
foreign particles on the collector electrodes.
Another object of the invention is to provide a dis- ;
charge electrode for electrostatic precipitators which, due to
its aerodynamic function, causes foreign particles in an air
stream to be aerodynamically projected toward the collector
electrodes and while at the same time the discharge electrode ;~
structure does not upset the desired flow or pressure characteris-
tics of the fluid at opposite sides thereof and ad~acent to
respective wet wall surfaces of collector electrodes.
Another object of the invention is to provide a novel
discharge electrode means for electrostatic precipitators ~hich
may be directly applicable to either annular in cross section
electrode assemblies or to the conventional flat electrode ~ :
assemblies.
` 20 Another object of the invention is to provide a '
variety of structures which may be adapted for use in collector
electrodes of electrostatic precipitators and mainly structures
, which are either screen like or foraminous with discharge points
on opposite sides thereof and sufficient openings or perfora-
tions so as to maintain even pressure and flow distribution
:- .
at opposite sides of the discharge electrode so as to avoid
: upsetting the desired laminar flow characteristics for efficient `;
aerodynamic and ionic collection of particles on the wet wall
surfaces of the collector electrodes.
-- 7
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~076488
Further ob~ects and advantages of the invention may be
apparent from the following specification, appended claims and
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a fragmentary top or plan view of an
electrode assembly of an electrostatic precipitator showing a
discharge electrode means between a pair of collector electrodes
and showing suspension means for the discharge electrode means;
Figure 2 is a side elevational view of the structure
shown in Fig. 1 and showing portions broken away and in section
to amplify the illustration.
Fig. 3 is an enlarged fragmentary sectional view of -~
the discharge electrode means taken from the line 3-3 of Fig. 2;
Fig. 4 is a fragmentary sectional view taken from the
line 4-4 of Fig. 3 showing the suspension means for the dlscharge
electrode;
Fig. 5 is an enlarged fragmentary view of screen like
structure of the discharge electrode as shown in Fig. 4~
Fig. 6 is an enlarged fragmentary sectional view taken
from the line 6-6 of Fig. 5 showing a cross section of the
screen like electrode structure disclosed in Fig. 5;
Fig. 7 is an enlarged fragmentary view similar to Fige 5
showing a modified form of the discharge electrode screen
structure;
Fig. 8 is an enlarged sectional view taken from the line
8-8 of Fig. 7 showing the cross sectional shape of the bars of
-the screen like structure shown in Fig. 7;
Fig. 9 i8 an enlarged fragmentary sectional view taken
from the line 9-9 of Fig. 7;
Fig. 10 is a fragmentary plan view taken in the same
direction as Fig. 1 showing an end of a modified form of the
,
~769~88
discharge electrode structure of the inventlon;
Fig. 11 is a view similar to Fig. 6 showing a further
modified form oE the discharge electrode structure of the
invention;
Fig. 12 is a fragmentary sectional view taken from the
line 12-12 of Fig. ll;
Fig. 13 is a fragmentary sectional view taken from the
line 13-13 of Fig. 12;
Fig. 14 is a view similar to Fig. 10 showing a further
modified form of the discharge electrode structure of the inven-
tion; and
Fig. 15 is an enlarged fragmentary sectional view taken -~ ~
from the line 15-15 of Fig. 14. ~ -
DESCRIPTION OF THE PREFERRED EMBODI~ENTS `
As shown in Figs. 1 and 2 of the drawings, the electrode
means for wet wall electrostatic precipitators of the invention
comprises a discharge electrode 20 and a pair of collector
electrodes 22 and 24. The collector electrodes 22 and 24
are provided with respective wet wall collector surfaces
26 and 28. These surfaces are adapted to operate with a film of
liquid flowing downward on them. ~
As shown in Fig. 2 of the drawings, the discharge -
electrode 20 is suspended by a plurality of rods 30 which are ;
supported on candelabra arms 32 which are supported in ~uxta- ;
position by means not shown. The discharge electrode 20 is
provided with a screen like or foraminous structure 34 having an
annular ring like frame member 36 at its upper end to which
the suspension rods 30 are secured by welding or other suitable
means.
The screen like structure 34 is preferably welded or
fused to the ring like frame 36 and this screen like structure 34
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107~8
Of the discharge electrode 20 at its lower end is provided with
a ring shaped frame member 38 to which the screen like structure
34 is preferably welded.
As shown in Fig. 4, it will be seen that the suspension
rods 30 are provided with externally screw threaded portions 40
on which nuts 42 and 44 are screw threadably disposed. These nuts 42
and 44 are vertically screw threadably adjustable on the screw
threaded portion 40 of each of the rods 30 and each screw
threaded portion of each rod 30 passes through a respective
horizontal member 32 which is preferably tubular in cross section.
The nut 44 on each rod 30 engages an upper side of the
respective member 32 and each nut 42 on each suspension rod 30
engages a lower portion of the respective member 32 so that the
suspension of the hollow cylindrical discharge electrode may be
adjusted in order to attain alignment suspension of the discharge
electrode concentrically between the respective wet wall surfaces
26 and 28 of the collector electrodes 22 and 24. The spacing
is critical to provide efficient Eormation of a proper corona
field and to avoid local and continuous arcing between the dis-
charge electrode and the collector electrodes to thereby achieverandom sparking throughout the precipitator. Accordingly, the
adjustability of the suspension rods 30 allows the collector
electrode to be properly aligned in direct concentric and parallel-
- ism with the respective wet wall surfaces 26 and 28 hereinbefore
described.
As shown in Fig. 2 of the drawings, the electrode struc-
ture when in operation receives air or gases flowing in the dir-
ection of the arrows A in Fig. 2 of the drawings upwardly between
the wet wall surfaces 26 and 28 and at opposite sides oE the
discharge electrode 20, it being seen that the discharge elec-
trode 20 and the collector electrodes 22 and 24 are annular in
-- 10 -
107~88
cross section concentric structures.
Referring to Fig. 3 of the drawings, it will be seen ~ ~;
that the screen like structure 34 of the discharge electrode 20
comprises generally a diamond shaped arrangement of bars designated
46 which are all integral with each other. The screen like struc- ,,
ture 34 as shown in Fig. 3 being an expanded metal structure initi-
ally formed and sheared from a flat sheet of metal. Some of the 'i
bars 46 are clipped off to form stubs 48 which form electrical
. ;. ~, .
discharge points and, as shown in Fig. 3, a substantially greater ~ , , '
number of these discharge points 48 are provided near the lower
or inlet end of the discharge electrode so as to provide a high -~
density corona field at the lower inlet end as indicated by the
arrows A in Fig. 2 of the drawings. The lower edge of the '~
ring shaped frame member 38 being provided with a plurality of '' ~ '
points 50 similar to those provided by the stubs 48j it being
noted that the clipping pattern may be varied in order to provide
a greater or lesser number of these discharge points and thus the
corona field density may be varied in the direction of flow of
particle laden air or gas which passes between the discharge ~;~
electrode 20 and the adjacent wet wall surfaces 26 and 28 of the -
collector electrodes 22 and 24.
The screen like structure 34 at the upper and lower ends ,~,
thereof is maintained in a substantially accurate rigid annular
form by the ring shaped frame members 36 and 38 and these members
36 and 38 as shown in Fig. 4 are preferably tubular members of
flattened cross sectional shape.
The suspension rods 30 as well as the frame rings 36 ' ~ -~
and 38 and the screen like structure 34 may all be made of
stainless steel or the like, however, Titanium is the preferred
material from whlch these parts are to be made inasmuch as
Titanium has been found to be very durable and efficient
",,, , , ,, , : , ,
1 ~7f~
in an electrostatic precipitator handling corrosive gases.
The screen like structure 34 made of expanded metal such
as shown in Fig. 5~ comprises integral, interconnecting parallel-
ograms, each having four bars designated 52, 54, 56 and 58, the
bars 52 and 54 being relatively short and the bars 56 and 58
being relatively long, the pattern being such that bars similar
to the bars 52 and 54 are clipped to provide the stubs 48 also
shown in Fig. 3 of the drawings, and these stubs project in
opposite directions from intermediate portions of the long bars
56 and 58 of each parallelogram all of which are integral with
each other and generally formed of expanded metal.
The cross sectional shape of each of the bars 52, 54, ~
56 and 58 is generally rectangular in cross section as shown in - ~ ; ;
Fig. 6 of the drawings and corresponds to the ends of the points
48 disclosed therein. All of the parallelogram portions of the
screen pattern are integral at the areas designated 60, all of
which is shown in Figs. 5 and 6 of the drawings. -
As shown in Fig. 6 of the drawings, the expanded metal
configuration is such that the bars generally designated 46 in
Fig. 3 of the drawings are disposed in an undulating relationship
such as to provide a substantially more rigid section than
would be the case of the sheet of metal had it been left in
flat condition. Accordingly, the increased section modulus
of the structure as shown in Fig. 6 provides for substantial
rigidity of the structure which is a relatively lightweight as-
sembly of bars relative to the overall size and area thereof.
This undulating structure shown in Fig. 6 having a substantial
section modulus is quite rigid and particularly so when formed
into the circular in cross section structures shown in Figs. 1
and 2 and thus affords rigidity compatible with the accuracy
of spacing required of the discharge electrode 20 relative to
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10764~38
:
the adjacent wet wall surfaces 26 and 28 of the collector elec-
trodes 22 and 24. ~`
In ~he modification of the screen structure 34 shown in
Fig. 7 of the drawings, the expanded metal is arranged in a
different clipped pattern to provide the point forming stubs 48.
This pattern comprises a plurality of parallelograms including ~-
one generally V-shaped portion 62 and a second V-shaped portion
64. The V-shaped portion 62 having an apex 66 and the V-shaped ;~
portion 64 having an apex portion 68. These apex portions 66 ,
and 68 being opposed to each other and each of the parallelograms
consisting of the V-shaped portions 62 and 64 being integral
with each other at areas 70 which correspond with the area 60 ~
as shown in Fig. 5. ~ -
The V-shaped portions 62 and 64 are provided with the clip- ~ -
ped stubs 48 at areas intermediate the integral portions 70 and ~`
the apex portion 66. Thus the stubs 48 are disposed at inter- ~ ~-
mediate portions between the apex portions and the portions 70
which are integral with adjacent parallelograms all generally
formed by the hereinbefore mentioned bars 46 of the expanded
metal and depending upon the clipping of these bars at particular
areas to form the stubs 48 which act as discharge points for the
discharge electrode 20 of which the screen like structure 34 is
a primary part.
~s shown in Fig. 8 of the drawings, each bar 46 is pro- ~,
vided with four corners 72. These corners being sharp due to the
fact that the expanded metal is sheared in the initial forming
and these corners 72 of the bars 46 are all capable of performing
as discharge points. Thus due to the undulating structural ar-
rangements as shown in Figs. 6 and 9 of the drawings, the corners
of the intersections 60 and 70 all function as discharge points
since they are at the lateral extremities of the screen structure
.
,.': . - , . . .
... .
1~7641~i18
34. Thus the screen like structure 34 of the discharge electrode
20 when Eormed of expanded metal is capable of providing for a
great many electrical discharge points or sharp edgea to provide
for a high density corona field and the open mesh of the structure
also has aerodynamic functional characteristics which cause the
Elow to depart away from the screen like structure 34 at an
acute angle approximating an angle in the range of four to five
degrees and thus the aerodynamic function causes gas flow and
the flow of particulate matter to progress away from the screen
like structure and toward the respective wet wall surfaces 26 and
28 of the collector electrodes 22 and 24, This aerodynamic ef- ~ -
fect is cooperative with the ionic effect on the particles for
forcing them toward the wet wall surfaces 26 and 28 of the
collector electrodes 22 and 24.
It will be seen that each of the intersectiona 60 as
shown in Fig. 6 is provided with four corner edges 74 which may ;~
serve as discharge points. These points 74 being at the lateral
extremities of the screen structure 34 and the intersections 70
shown in Fig. 9 of the drawings are provided with sharp corner ~-
edges 76 which are also at the lateral extremities of the screen
structure 34 and thus they serve as discharge points for the dis-
charge electrode 20.
~ dditionally, it will be seen that similar sections 78 as
shown in Fig. 7 of the drawings are disposed between the stubs 48.
These sections 78 are provided with corners 80 similar to the -
corners or edges 76 and they also provide substantial discharge
points. Likewise portions 82 form intersections between the
stubs 48 shown in Fig. 5 of the drawings, and these portions
82 have a similar cross section to the integral portion 60 shown
in Fig. 6 and they also have similar corners structurally equiva-
lent to the corners 74 which are at the lateral extremities of
- 14 -
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107~4t~
the screen like structure 34 and thus they also provide discharge
point capabilities.
In ~he modification as shown in Fig, 10 of the
drawings, a discharge electrode 88 is of annular form but shown ;
fragmentarily and Fig. 10 discloses the discharge elect~ode in
the same plane as that shown in Fig. 1. This discharge electrode ;
: .
88 is formed of a sheet of metal having generally triangular taba ;; -
~90 punched therefrom and extending in opposite directions at
opposite sides oE the plate to form discharge points~ These tabs
90 being similar to the tab structures as will be hereinafter des~
cribed in connection with the disclosure of Fig. 11 and 12 of the
drawings.
It will be seen that the plane of these tabs 90 may be
at right angles to the direction of flow and the openings from
which the tabs are punched out provide for equalization of pressure
to maintain proper flow distribution as will be hereinafter des--
cribed in connection with the disclosure of Figs. 11 and 12.
As shown in Fig. 11 a sheet of metal designated 92
is provided with a plurality of punched out openings 9~ from
which tabs 96 are projected laterally of the plate~ These tabs
being shown in Figs. 12 and 13 of the drawings and are generally
triangular and disposed in opposite directions from the sheet 92.
The tabs 96 are each provided with an apex point 98
and thus provide discharge points of opposite sides o e the sheet 92.
As shown in Figs. 11 and 12 these tabs 96 are
parallel to the axis of flow indicated by the arrow A which corres-
pond with the arrows A in Figs. 2 and 3 of the drawings. The
structure shown in Fig. 10 of the drawings has the tabs 90 dis-
posed at right angles generally to the direction of flow or
may have them at an angle to the flow if desired but depending
upon certain requirements of electrostatic precipitators having
.
' . ' ' ' , , ~ , , ~ ' . ' , . ,
... . ~, .
~0769L8~
varying configurations which may be desired. ~,
It will be seen that each of the tabs 96 when punched ~;
out of the plate 92 leaves a respective opening 100 and these
openings 100 may approximate twenty percent of the overall area of
the plate 92 so as to provide for equalization oE preasure and
flow characteristics at opposite sides oE a discharge electrode
formed of such structure as shown in Fig. 11 and 12 and also , -
that shown in Fig. 10.
It will be seen that the structure shown in Fig. 11
is a perfect structure and may be defined as a foraminous, structure ,~' '
but not necessarily as a screen atructure.
As shown in Fig. 14, a modified discharge electrode ~ -
structure shown on the same plane aa that shown in Fig, 1 and this
structure comprises a sheet metal plate 102 to which have been
spot welded or otherwise aecured bara having generally L-shaped
configuration, these bars being designated 104. Th,ese bars 104
are provided with edges 106, each h,aving a plurality of triangu- -
lar points 108. These points 108 may be spaced apart as shown
in Fig. 15 to vary the flow density in the dîrection of the air
flow as indicated by the arrow A in Fig. 15 which corresponds
with that of Figs. 2 and 3 of the drawings. The L-shaped bars
104 project from oppoaite sides of the plate lQ2 and all have
the triangular points 108 projecting therefrom to provide dia~
charge points. Additionally the plate 102 as shown in Fig. 15 ~ '
is provided with openings 110 thereth,rough, These openings 110
may constitute substantially twenty percent of the area of the
plate 102 so as to provide for preasure and flow equalization
at opposite sides of the plate and to thereby maintain even
flow characteristics adjacent to the wet wall surfaces 26 and 28
of the collector electrodes 22 and 24. ~ ;
It will be seen that th,e concentration of the points
- 16 - ,
~ ',. '
: . . .
;
~07~;4~38
108 may vary in a direction of the flow A and thereby provide -
for a high dènsity corona field ad~acent the inlet between the collector elec- - :
trodes 22 and 24 as described in connection with Fig. 2 of the
drawings, the inlet being at the lower ends of the electrodes
and thus the plate 102 may be a foraminous plate provided with
points extending from opposite sides thereof toward the respective ;
collector electrodes. The structures shown in Figs. 10 to 15
of the drawings are preferably made of Titanium due to the fact
that it has been discovered that Titanium provides an unexpected
result; namely, that it is very durable in the environment
of an electrostatic precipitator.
Heretofore, such discharge electrodes have been made
of stainless steel or the like and have eroded away ~uite rapidly,
The environmental conditions in an electrostatic
precipitator comprise high voltage discharge from the discharge
electrodes as well as various viscous and vapor conditions
which has heretofore caused erosion of discharge electrodes and
which has not been particularly predictable and in accordance
with the present invention or discovery, Titanium has been found
to be extremely durable under these environmental conditions.
It will be obvious to those skilled in the art
that various modifications may be resorted to without departing
from the spirit of the invention,
..
