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Патент USA US2412912

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Def» 17, 1946.
Filed sept. 25. 1944
3 Sheets-Sheet 2
,Dec- 17, 1946.
w. M. scHM‘IDT ET A1.
Filed Sept. 25, 1944
Fg. 6.
5 Sheets-Sheet 3
Patented Dec. 17, 1946
Walter Malcolm Schmidt and Donald K. Town-`
send, Los Angeles, Calif., assignors to Western
Precipitation` Corporation,` Los Angeles, Calif., ‘
a corporation of California ~
Application September 23, 1944, Serial No. 555,490
5 Claims. (Cl. 183-7)l
. 2
This invention relates to collecting electrodes
tions, as shown for example in United States pat
of electrical precipitation apparatus for use in
ent of Anderson, No.Y 2,192,172, issued March 5,
the separation of suspended material from gases,
and’ particularly to collecting electrodes of the
Electrical precipitat‘ors of the types above de
type in which a thin film of liquid is passed, pref 5 scribed are well known in the art. The present
erably continuously, over the collecting electrode
invention is concerned only with an advantageous
surfaces on which the material is precipitated.
form of collecting electrode structure for use in
Although the principles of the invention are
any type of precipitator employing vertical liquid'
applicable to any type of liquid-ñushed collecting
fiushed collecting electrodes, and it` will be under
electrode, the advantages of the invention will be
stood that such electrode structures may be used
more particularly described in connection with
in connection with any'type or form of opposing
liquid-flushed collecting electrodes comprising
precipitating electrode.
vertical pipes or tubes. Such collecting electrodes
are ordinarily assembled within a housing and
mounted adjacent their-*upper ends on a horizon
tally extending wall or header plate. The gas is
passed vertically through the collecting electrode
pipes, and an opposing precipitating electrode ex
tends centrally within each pipe. Water or other
suitable liquid is supplied to the space aroundthe
upper ends of the collecting electrodes above the
headerplate, and iiows over the upper edges of
these electrodes and down the inside surfaces
In the treatment of largev volumes of gas, it is
customary to provide a considerable »numberv of
collecting electrode pipes in a single unitl or sec
tion of the precipitator, and it is desirable to
maintain a substantially uniform flow of liquid
down the inner surfaces of al1 the pipes. Al
though the liquid reservoir above the header plate
may be subdivided by partitions into a number of
separate compartments, the arrangement is gen
erally suchA that each suchV compartment sur
rounds and supplies liquid to- a plurality of the
thereof, on which the material is precipitated..-`V` electrodes. It is therefore advantageous to pro
The space above the header plate constitutes a "25 vide for adjusting the4 upper edges of the indi
liquid supply chamber or reservoir, and the upper
vidual electrodes», over which the liquid flows.
ends of the collecting electrodes extend upward
The means for this' purpose- should preferably be
ly above the header plate and act as overflow lips
such as to provide' not only for Vvertical adjust-g-
or weirs to control the ilow of Water into each
An electrical precipitator of this general type is
shown 'in United States patent of Crowder et al.
ment of the overflow lip or weir atthe upper end
30 of each electrode in order to maintain substan
tially equal flow of liquid from the surrounding
space into the several electrodes, but also for ver
tical angular adjustment of such overflow lip or
iiushed pipe collecting electrodes are useful in l weir in order to secure substantially uniform iiow
precipitators of the single-stage type, as disclosed ci of liquid at different positions around the circum
in the above-mentioned patent, in which the pre
ference of each electrode and thus insure substan
cipitating electrodes within the pipes are dis
tially uniform iiow of liquid over all portions of
charging electrodes such as small diameter wires,
the collecting electrode surface.
or rods provided with sharp edges or points,
The collecting electrode pipes are generally of
whereby a corona discharge is maintained for the 'llo substantially uniform diameter throughout the
purpose of both charging and precipitating sus
major portion of their height to provide the de
pended particles in the electric ñeld between
sired spacing of the collecting surface, and the
No. 1,968,334, issued Ju1y 31, 1934. Such liquid
these electrodes and the collecting electrodes.
Similar liquid-flushed collecting electrodes are ,.
also useful in electrical precipitators of the two
stage type, in which the charging and precipitat
ing of the suspended material are carried out in
successive spatially separated fields. In this case
the precipitating electrodes within the pipes may
comprise non-discharging electrode members of
extended surface, such as smooth rods or pipes of
sufficient diameter to substantially avoid corona
discharge; or the precipitating electrodes may
liquid film thereon, from the opposing electrode.
It' is desirable that this portion of the collecting
electrode surface be free from sharp edges or
other irregularities or discontinuities that would.
tend to disturb the smooth flow of the liquid ñlm
or to cause electrical discharge from the collect
ing electrode. Itis also desirable that the upper
end portion of the collecting electrode including
the overflow lip or> Weir at which the liquid film
is formed, as well as the lower end portion of the
collecting electrode where the liquid leaves the
Collecting Surface, be of materially greater diame
comprise composite electrode elements provided
with both discharging and non-discharging `por 55 ter than the major portion of the pipe, so as to
Fig. 1 is a partial vertical section of an elec
prevent electric discharge from the ends of the
trical precipitator with several collecting elec
collecting electrode and to provide for forming
trodes embodying the principles of the invention
and breaking the liquid film at positions of re
and associated precipitating electrodes shown in
duced electric field strength.
It has been found, however, that in spiteof the UI elevation;
Fig. 2 is a horizontal section on line 2-2 of
most careful vertical and angular adjustment of
Fig. 1;
the upper end portions of the collecting elec
Fig. 3 is an’enlarged vertical section of the
trodes in .precipitators of the types described
upper end of one of the collecting electrode struc
above, inequalities of flow between different col
lecting electrodes and at different points of the `
circumference of the individual electrodes are dif
ficult to eliminate. Such inequalities of flow are
tures of Fig. 1;
. '
Fig. 3a is a fragmentary detail of the collecting
electrode structure of Fig. 3;
Fig. 4 is a vertical section of the upper end
particularly apt to arise after the precipitators
of a modified embodiment of the collecting elec
are put into operation, due to slight variations
in rate of supply of fiushing liquid, arising, forA ]5 trode structure of the invention;
Fig. 5 is a partial plan view of the collecting
example, from partial plugging of feed lines, or
electrode structure of Fig. 4;
to small shifts due to settling.
Fig. 6 is a vertical section of the upper end of
We have now found that the adjustment of
the level of the upper ends of the collecting elec
trodes can be rendered far less critical and sub
stantial equality of flow'to the individual col
lecting electrodes and about the circumference
-thereof can be maintained in spite of consider
a further embodiment of the collecting electrode
structure of the invention;
Fig. 'l is a partial plan view of the collecting
electrode structure of Fig. 6;
Fig. 8 is a fragmentary diagrammatic plan view
of the top of the collecting electrode structure of
_able variations in the supply of flushing liquid,
shifts in level of the apparatus and other chang 25 an electrical precipitator including vertical plate
collecting electrodes embodying the principles of
ing conditions of operation, by providing a sub
stantial hydraulic head of flushing liquid adja
the invention;
Fig. 9 is a fragmentary vertical section of the
`cent the upper ends of the collecting electrodes,
upper portion of the collecting electrode struc
and particularly by providing a throttling curtain
adjacent the Weir lip at the upper ends of the 30 ture of Fig. 8;
Fig. 10 is an enlarged fragmentary detailiin
collecting electrodes whereby a controlled flow of
vertical section, and Fig. 11 is an enlarged frag
liquid to the Weir lip is maintained under a sub
mentary detail in plan of the embodiment of
Fig. 8;
vide a collecting electrode structure which can 35 Fig. 12 is a diagrammatic plan view of the top
stantial hydraulic head.
A principal object of this invention is to pro
be easily adjusted to provide equal flow of flush
of the collecting electrode structure of an elec
trical precipitator including rectangular vertical
ing lliquid over the entire collecting surface of
gas treating ducts embodying the invention; and `
`each of the collecting electrodes of a group.
Fig. 13 is an enlarged fragmentary detail in
v A further object of the invention is the provi
sion of a collecting electrode structure which will 4° vertical section on une ls-Ia of Fig. 12.
In Figs. l and 2, a plurality of tubular collect
maintain an equal flow of liquid over the entire
ing electrodes I are shown as extending vertically
collecting surface of each of the collecting elec
through and supported upon a header plate 2,
trodes of a group in spite of substantial changes
vin liquid supply, level, or other operating condi
it being understood that these electrodes are or
dinarily mounted within an enclosed precipitator
housing provided with gas inlet and gas outlet
` Another object of the invention is to provide
means at opposite sides of the header plate so
a collecting electrode structure which will main
as to provide for passage of gas to be treated
tain a controlled constant rate of iiow of liquid
vertically through the several electrodes, as is
to the upper end of the collecting electrode under
more fully shown and described in the above
a substantial hydraulic head.
These and other objects and advantages which
mentioned United States Patent No. 1,968,334.
Each collecting electrode comprises a pipe 3
will be apparent from the further description of
of suitable length and diameter, which is of sub
the invention are attained by the collecting elec
stantially uniform diameter throughout the
trode structure of the invention which broadly
comprises a vertically-extending electrode mem 55 major portion of its length. 'The upper end of
ber providing a collecting surface of extended
the pipe extends above the header plate 2, and
area, the upper end portion of the electrode car
rying a Weir substantially coextensive With the
upper end thereof, and a throttling curtain ad
is ñared outwardly as shown at 4 to provide an
upper edge 5 of materially greater inside diameter
than the major portion of the pipe. At the up
jacent the Weir, the throttling curtain extending 60 per edge the external surface of the pipe is pref
erably finished so as to provide a short cylindri-l
a substantial distance above the Weir and being
cal bearing surface 6, as shown more particularly
spaced therefrom to provide a constricted passage
in Fig. 3.
to the Weir from a body of liquid adjacent the
Each of the collecting electrodepipes extends
throttling curtain. Preferably the throttling cur
tain is formed to provide a plurality of constrict 55 through an opening 8 in header plate 2 and is
shown as supported on said header plate by
ed passages substantially equally spaced along the
means of an outwardly projecting annular flange
9 Welded or otherwise secured to the pipe and
The weir may be an integral part of the upper
supported on the header plate. A suitableV gas
end of the collecting electrode or it may be ad
justably carried thereby either as a separate 70 ket Ill is preferably provided between ñange 9
and header plate 2 and the ñange is shownl as:
member or Vas an element of the throttling cur
secured to the header plate by means of bolts>
il, thus providing a fluid-tight connection be
The invention will be more particularly de
tween the header plate and each pipe.
scribed With reference to the accompanying draw
75 An adjustable Weir ring I2 is mounted in po
ings, in which:
sition around the‘upper end of each pipe 3, With
its cylindrical inner surface in close sliding en
sagement with cylindrical face 6 on the pipe.
Ring I2 extends upward above the upper edge
5 of the pipe and is provided with a plane upper
edge I3. Means are provided for supporting and
`lecting electrodes to cause corona discharge» from
discharge electrodes> 3 I.
After the apparatus is erected, but preferably
before the throttling rings 2| are installed, a
suitable liquid is supplied to each of the com
partments deñned by walls 24, and the weir rings
adjusting the Weir ring, comprising for example
I2 of the several collecting electrodes in each
four adjusting screws or bolts i5, extending
of such compartments are adjusted as described
through outwardly projecting members such as
lugs I 6 at equally spaced positions around the 10 4above to provide substantially equal flow »of liquid
into the respective electrodes and substantially
ring and provided with heads I'I and nuts I8
equal flow of liquid at all circumferential posi~
bearing against the upper and lower faces, re
tions around the upper edge of each of the weir
spectively, of said lugs. The lower` ends of ad
justing screws I5 engage nuts or other internally
throttling rings 2i are put in
threaded members I 9' welded or otherwise se»
level is raised above the
cured to flange `9. Thus, by suitable manipula
tion oi’ screws I 5 and nuts i8 the weir ring I2
may be raised or lowered at the position of each
adjusting screw, so as to provide vertical ad
justment of the weir ring relative to pipe 3 and
also for vertical angular adjustment of said ring
relative to said pipe. Although the ring ñts
quite closely about the external face ö at the
upper end of the pipe in order to provide a sub
level of the Weir lip to provide a substantial hy
:aulic head at the level of the weir lip. This
head, together with the throttling action of con
stricted flow passages 23, results in the damping
out of the effects of fluctuations of level
liquid supply compartments and eliminates or
greatly reduces the eifect of small changes in
level of the apparatus, thereby maintaining a
stantially liquid-tight engagement, the relation- 'i substantialiy uniform downward iiow of liquid
through` all the electrodes in a thin ñlm dis
tributed substantially uniformly over the entire
duly limit such tilting.
movement, and the ñt at "
this point need not be extremely close in order
to substantially prevent leakage of liquid be
tween the pipe and the ring.
Surrounding the upper ends of the weir rings
I2 are corrugated throttling rings ZI which may
be-formed by fastening a suitable strip of cor
suitable material by rivets
inner surface of each electrode.
The liquid ñlm is formed- at the upper edge
of the weir ring at a position spaced from the
opposing precipitating electrode 3l by a distance
materially greater than the spacing between the
precipitating electrode and the major portion
of the inner surface of the- collecting electrode,
so as to avoid electrical disturbances.
The en
tire surface over which the liquid ñows between
the top and bottom edges of each collecting elec
trode is preferably free from sharp edges or
surface discontinuities' or irregularities that
y might tend to
disturb the smooth flow of' the
40 liquid or to cause electrical disturbances.
Although the precipitating electrodes are in
case shown as discharge electrodes. it will
of the Weir. 'I‘he depth of the corrugations may
be understood that the collecting electrode struc
advantageously be of the order of it; inch.
ture of this invention may also be employed with
The space above the header plate 2
non~discl1arging precipitating
brought out hereinabove.
' ‘ and this space may be di
embodiment of the invention shown in
Figs. »i and 5, the Weir is provided by the upper
edge 5 or" the flared upper portion lâ of pipe 3L
50 The iiow of liquid to the Weir lip is throttled by
means of. the constricted passages 4I provided
provided between adjacent walls 24. Liquid for 55
ñushing, such as water, oil, or any other suitable
liquid, is supplied through pipes 25 and down
wardly-extending nipples 2t which deliver the
liquid above the header plate and below the Weir
in position,
rings, as indicated in Fig. 1.
60 critical or sensitive to subsequent changes of
The precipitating electrodes are shown as com
level of the apparatus.
prising discharge electrode members 3| , such as
In the form of the invention shown in Figs. 6
wires or square twisted rods, extending axially
and 7, both the Weir and the constricted passages
through the collecting electrodes and supported
are provided by the annular U-shaped member
at their upper ends by suitable supporting frame 65 58. The upper end 52 of the inner and shorter
means such as are indicated at 32, 33 and 34 in
Fig. 1.
The collecting electrodes are ordinarily main
tained at ground potential, while the entire dis
weir lip, and the
charge electrode system including discharge 70 The flow of liquid to the weir
electrodes 3| and the associated supporting and
spacing means is mounted on insulating 'sup
ports, so that the necessary high potential may
be maintained between the discharge and col
sage 54 between the outer, longer limb 53 of the
U and the inner limb 5! is further throttled in
passing through the inlet openings 55. The weir
lip may be adjusted to and maintained in level
75 position
by means of suitable leveling blocks 56.
The level of the liquid in the liquid compart
ment is maintained at a substantial height above
the'level of the Weir lips in the collecting elec
trode structure, varying in accordance with the
rate of iiovv desired on the inner surfaces of the
collecting electrodes and with the eñective fric
tional resistance of the constricting passages. In
general, a hydraulic head of from about 1/2 inch
to about 4.- inches will be found to be suitable.
In the precipitator illustrated in Figs. 8-11,
the principles of the invention are applied to
vertical plate collecting electrodes,Y consisting for
example of concrete plates 60, spaced from com
plementary discharge electrodes El. Along the
tops of the plates Sil are horizontal troughs 62,
communicating with end troughs'63 supplied with
iìushing liquid by pipes 64.
viding a Weir at the upper end of said electrode
member and extending along the upper end of
said collecting surface, means providing a liquid
reservoir adjacent said Weir and a corrugated
curtain member extending from substantially
below to substantially above the level of the Weir
and contacting the Weir means to provide con
stricted passages for the ñovv of liquid from the
reservoir to the Weir.
2. A collecting electrode for use ' in liquid
flushed electrical precipitators comprising. a.
vertically-extending pipe, means providing a.
circumferential Weir at the upper end of the pipe,
and a vertically corrugated cylindrical member
circumferentially contacting the Weir means t'o
provide a plurality of constricted passages for
the flow of liquid to the Weir.
, . _ '
3. A collecting electrode for use. in liquid
flushed electrical precipitators comprising a.
lecting surfaces of plates 60 is formed by the
upper edges of the side members of troughs 62. 20 vertically-extending pipe having its upper end
portion flared to provide an upper edge of mate
Corrugated strips 65, held in position against the
rially greater inside diameter than the major
sides of the troughs by stiff strip members 66 and
portion of the- pipe, means providing a circumfer
leaf springs B1, shown more particularly in Figs.
ential Weir at said upper edge of the pipe, and a
10-11, provide a series of constricted liquid flow
25 vertically corrugated cylindrical member circum
passages to the Weir lips.
ferentially contacting the Weir means to provide
.In the embodiment of the invention shown in
A The Weir lip along the top of the vertical col
Figs. 12-13, vertical wall members 10, 1li’ form
a plurality of constricted passages for the flow
ing rectangular vertical gas passages form col
of liquid to the Weir. Y
4. A collecting electrode for use in liquid
lecting electrode surfaces complementary to dis
charge'electrodes 1|. The upper edges of the 30 flushed electrical precipitators comprising a
vertically extending pipe, means providing `a cir
horizontal troughs 'l2 forming liquid reservoirs at
cumferential Weir at the upper end of the pipe,
the top of the rectangular gas passages are bent
means providing a reservoir for. liquid adjacent
away from the gas passages to provide Weir edges
the upper end of the pipe, and means providing
13 spaced apart a greater distance than the Width
of the passages to reduce the velocity of the gases 35 a plurality of constricted passages substantially
at the level of the Weirs. Liquid is supplied by
equally spaced along the Weir for the ?loW of
pipes 14. Corrugated strips ‘l5 are maintained in
liquid from the reservoir to the Weir.
position at the back of the Weir edges as shown
5. A collecting electrode for use in liquid
in Figs. 10-11 or by other suitable means to pro
flushed electrical precipitators comprising a
vide constricted passages for liquid flow to the 40 vertically extending electrode member providing
a'collecting surface of extended' area, means pro
It Will be seen that the principles of the in
viding a Weir at the upper end of said electrode
vention may be applied in a Wide variety of forms
member and extending along the upper end of
which are characterized by the provision of a
said collecting surface, means providing a liquid
Weir and means for constricting the ñoW of liquid 45 reservoir adjacent said Weir, and means provid- f
to the Weir as defined in the claims.
ing a plurality of constricted passages substan- i
tially equally spaced along the Weir for the flow "
We claim:
l. A collecting electrode for use in liquid
of liquid from the reservoir to the weir.
flushed electrical precipitators comprising a
vertically-extending electrode member providing 56
a collecting surface of extended area, means pro
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