Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF INVE~TION
The present in~ention is directed to rotary valves
of the character disclosed in U.S. Patent 3,780,916; 3,912,134;
and 3,764,047 all found in United States Classification 222,
with varying subclasses.
SUMMARY OF PRIOR ART
In addition to the above-described patents, German
Publication 2,411,800 and Swiss Patent 374,454 also disclose
rotary valves all of which are basically provided for present-
ing two different nozzles or pour tubes to a single teeming
opening at the bottom of a teeming vessel. The principal
advantage of a rotary type valve is to provide a greater length
of travel of the imperforate portion of the rotating member
than with a reciprocating type valve, to the end that erosion
and break-out can be reduced.
~igh manganese steels are highly erosive. In a
shop with a 300 ton ladle, where five ton ingots are being
poured, 60 separate shut-offs are required in order to empty
the ladle. A typical reciprocating sliding gate will not
last for this many shut offs. Accordingly the advantage of
a rotary valve, where that many shut-offs can be achieved,
is self evident. The valves of the prior art, however, are
of special construction, and do not provide for the easy and
quick replacement of nozzles.
Another problem faced in teeming molten metal is
a freezing of the metal at the lower edge of the pour tube.
This phenomenon is referred to as bugging. Once bugging
begins, the original build-up of frozen metal provides a
surface for additional build-up., By utilizing a low conduc-
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tivity material, the phenomenon of freezing or bugging can
be dealt with successfully, but such a material erodes more
rapidly and consequently such a nozzle should be replacable
during the life of the valve. In addition, if a replaceable
lower nozzle is provided, a smaller hole can be used to
start the pour with a high head and, as the head is reduced,
the erosion will open the hole and thus maintain an even
teeming rate.
When using a submerged tube when the vessel is
clogged it is very difficult to open for a pour. With a
rotary valve having a short tube an oxygen lance can be used
to open and then the valve rotated to commence the pour
through the submerged tube. The submerged tube may also be
attached after the ladle is filled using the same bayonet
type attachment.
SU~MARY OF INVENTION
The present invention is directed to a rotary valve
for vessels teeming molten metals, and in particular to such
a valve in which the lower portion of the nozzle of the
rotary gate can be replaced. To provide for the same, the
metallic material encasing the rotary plate as well as its
depending nozzle extensions are provided with interlocking
fastener means which permit the removal and replacement of a
bottom portion of a nozzle to replace the same, particularly
when erosion or bugging has occurred. The invention is also
directed to a top plate and rotary gate which are formed from
identical members, two or more on the top plate and two or
more in the rotary gate. The nozzles used in the top plate
are matingly engaged with collars provided on semi-circular
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recesses on the plate to the end that no erosion or molten
stee] directly contacts the top plate or rotary gate plates
except in the shut-off condition. In this fashion both the
openings can be developed from different ceramics having the
appropriate erosion and conductivity characteristics to deal
with the type of metal belng poured.
The method of the invention comprises the steps of
assembly of the top plate and rotary gate from four or more
identical members, each being positioned opposite a like
member and defining nozzle receiving members having a collar
extensible into the corresponding groove within the plug or
pouring member. The same are then assembled and retained in
a case to secure them in leak tight relationship. The lower
member is provided further with nozzle cases having lock type
projections which permit the insertion and removal of the
nozzle extension. This method effectively permits the inser-
tion of larger and smaller bore diameter nozzle extensions
as well as the utilization of low conductivity, inserts to
combat freezing and bugging which would otherwise occur in
pouring certain steels with a high conductivity ceramic
having better erosion characteritics.
Accordingly a principal object of the present
invention is to provide a rotary valve in which the lower
portion of the pouring nozzles of which can be changed easily.
An additional object of the present invention is
directed to a rotary valve having its pouring portions and
imperforate portion formed from a single sector, and providing
for the mechanical retention of varying pouring elements
which can be formed from a most desirable ceramic material
for the particular metal and pouring operation.
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Still another object of the present invention is
to provide a method of assembling a rotary valve replaceable
refractory portion which permits customizing the top plate
and the rotary gate to the pouring conditions of a given
customer, without requiring extensive tooling, and substantial
inventory of top plates, rotary gates, and pour tubes.
Yet another object of the present invention is to
provide a method for combating the difference in a head in a
teeming vessel between the beginning of a pour and the end
of the pour having widely varying flow rates.
A further object of the present invention is to
provide a rotary valve and method for producing the same
which is inherently safe in operation, and minimizes the
potential of bxeak-through, leakage, and an open pour
condition which is not controllable by the operator.
A further object of the present invention is to
provide a rotary valve which is easily and quickly serviced
with replacement refractories by non-technical and inexperienced
labor under the adverse working conditions of a steel mill
pouring pit.
These las~ two objects are accomplished by utilizing
pressure devices distributed under the entire area of the
rotating plate to constantly urge it upward against the sta-
tionary plate. The pressure applied by these pressure devices
is sufficient to deflect the plate and its surrounding metal
case within their elastic limits so that the rotating plate
conforms to the stationary plate even if the stationary
plate is not completely flat. The resiliency of these
pressure devices also allows for variations in plate thickness
and for overtravel when devices such as the toggle devices
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utilized in the illustrated embodiment are used for attaching
the supporting frame to the vessel.
DESCRIPTION OF DRAWINGS
Further objects and advantages of the present inven-
tion will become apparent as the following description proceeds,
taken in conjunction with the accompanyiny illustrative draw-
ings in which:
FIG. 1 is a front elevation of a lower portion of
a pouring vessel utilizing a rotary valve illustrative of
the present invention.
FIG. 2 is a bottom view of the rotary gate valve
of FIG. 1 and showing the same in the same scale.
FIG. 3 is a transverse sectional view of the rotary
valve of FIG. 2 taken along section line 3-3 of FIG. 2 showing
the interior portion of the differing diameter nozzles in
the rotary gate.
FIG. 4 is a longitudinal sectional view taken
along section line 4-4 of FIG. 2, showing in phantom lines the
open and closed configuration of the rotary gate frame.
FIG. 5 is a horizontal section taken along section
line 5-5 of ~IG. 3 showing the interior portion of the rotary
valve and more particularly the gear mechanism for driving
the same.
FIG. 6 is an exploded perspective view illustrating
the method of forming the top plate from two identical members.
FIG. 7 is an exploded perspective view of the method
of forming a rotary gate with two nozzles utilizing the two
plate members also used in connection with the top plate,
and further illustrating the method for removing the two
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lower nozzle extensions.
FIG. 8 is an exploded perspective view of the rotary
gate like FIG. 7 but directed to an alternative embodiment
having a single nozzle.
FIG. 9 like FIGS 8 and 7, is an exploded perspective
view oE the rotary gate but directed to yet another alternative
embodiment having six nozzles.
DESCRIP~ION OF TWO NOZZLE EMBODIMENTS
The present invention finds its principal utility
in conjunction with a pouring vessel V, such as shown on FIG. 1,
the pouring vessel primarily being a ladle for teeming molten
metal, usually steel. Nonetheless other molten metals are
contemplated. The rotary valve R, as shown in FIG. 1, is
positioned beneath the vessel V, and has a single pouring
opening operative at any one time extending beneath the frame
16 as shown in FIG. 1. More specifically, as viewed from
the bottom, as shown in FIG. 2, the rotary valve R has a
nozzle extension 52 with a large pour opening and a nozzle
extension 54 with a small pour opening extending beneath a
support ring 62 for the rotary gate carrier 61.
Turning now to FIG. 3, it will be seen that the
vessel V includes a metal shell 10 as its outer portion, and
an interior refractory lining 11. A hole is provided in the
lower central portion of the refractory lining 11 for the
mounting of a well block 12, which further contains interiorly
thereof a working nozzle 14, which is in teeming communication
with the bottom of the vessel V.
Desirably a safety collar 15 is provided peripherally
around the working nozzle 14, and is secured to the frame 16
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and its mounting plate 18. The frame 16 of the rotary valve
R extends around the rotary valve R, but its upper portion 18
defines the mounting plate which, as seen in FIG. ~, is secured
to the metal shell 10 of the pourlng vessel V by means of
mounting bolts 19.
A top plate 20 (as seen in FIG. 3) is positioned
within a top plate block ring 17 which depends from the mounting
plate 18. A rotary gate ~0 is positioned beneath the top
plate 20, and held thereagainst by means of the pressure
devices 60 which are mounted within the rotary gate carrier
61. The rotary gate carrier, in turn, has a lower face which
is positioned atop the support ring portion 62 of the frame
16. Further as will be noted in FIG. 3, a splatter shield
64 is provided in surrounding relationship to the nozzle cases
50. Provision for removing the top plate as well as the
rotary gate 20, 40 is shown in FIG. 4 where it will be seen
that the rotary gate carrier 61 is secured within the frame
16 by means of a pivot toggle 65 secured to the mounting
plate 18, which has a pivot toggle actuator 66 permitting
the same to be pivoted to a distance in greater space relation-
ship from the mounting plate 18 than in normal operation.
Similarly, at a station on the opposite side of the rotary
gate carrier 61, provision is made for a latch toggle 68
which is engaged by a latch toggle activator 69, permitting
a lowering and tilting of the rotary gate carrier 61, to a
position such as shown in phantom lines in FIG. 4 for removal
and servicing.
Turning now to FIG. 5, it will be seen that the
rotary gate R is driven by means of a bull gear 70 having a
plurality of peripheral teeth 71. A rotary gate recess 72
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is provided interiorly of the bull gear 70, and contains the
rotary gate 40, the same being secured in place by means of
the flats in the rotary gate recess which engage corresponding
flats 44 on the rotary gate and the curvilinear portion 42
on the rotary gate as shown in FIG. 7. The bull gear 70 is
driven by means of a drive pinion 75 the peripheral teeth
74 of which engage the teeth 71 and through a drive mechanism
76 (see FIG. 2) the drive pinion 75 is actuated to perform
a rotation of the rotary gate 40.
The specific construction of the top plate 20 is
highlighted in FIG. 6 where it will be seen that a metallic
case 21 is provided having opposed curved depending side walls
22, and opposed locking flats 44. A pair of identical re-
fractory plates 25 are provided, each of which has two semi-
circular recesses 26 containing a locking collar 28 and an
undercut 29. A top plate nozzle 30 is engaged by two of the
opposed semi-circular recesses 26, the top plate nozzle 30
having a pour opening 31 at a central portion, and a locking
groove 32 around its periphery, the locking groove being
engaged by the opposed locking collars 28 of the semi-circular
recesses 26 in the refractory plates 25. This permits the
upper portion of the top plate nozzle 30 to extend above the
metallic case 21, and (as shown in FIG. 3) be received by
the safety collar 15 provided beneath the working nozzle 14
of the teeming vessel V. The safety collar ring 34 of the
top plate nozzle thus is secured to the principal teeming
opening in a safety relationship. Also to be noted is the
provision of a top plate plug 35 which also has a locking
groove 36, which is received by the opposed locking collars
28 of the refractory plates 25 and which engage the locking
grooves 36. The mount lock extens.ion 38 of the top plate
plug 35 fits within a plug recess 33 provided at a lower portion
of the mounting plate 18 as shown in FIG. 3. Nozzle access
ring 37 and plug access ring 39 are provided in the metallic
case 21, and the parts, when assembled, are mortared into
and securely bound within the metallic casing 21 to thus
define a completed top plate 20.
Turning now to FIG. 7, it will be seen that a
rotary gate 40 also contemplates a metallic case 41, and the
utilization of the same identical refractory plates 25 as
utilized in the top plate 20, and where parts are common,
common reference numerals will be employedO The refractory
plates 25 thus employed in the rotary gate 40, also are pro-
vided with a semi-circular pair of recesses 26, and a locking
collar 28 with a corresponding undercut 29. The metallic
case 41 has curved side walls 42, as well as opposed locking
flats 44. Provision is made for a large bore nozzle 45
having a locking groove 46, which is matingly engaged by one
of the locking collars 28 of the opposed refractory plates
25. The large bore nozzle 45 is proportioned so that its
upper surface does not extend above the upper surface of the
opposed refractory plates 25O Correspondingly, a small bore
nozzle 48 is provided having a locking groove 49 which
similarly is engaged by the opposed locking collars 28.
The small bore nozzle 48 portion of the rotary gate 40
also has a locking groove 49, which is engaged by the opposed
locking collars 28 of the refractory plates 25. Both of the
nozzles 45, 48 extend downwardly through nozzle access rings
59 in the metallic case 41. Both of them extend into the
depending nozzle cases 50 which have an extension lock 51 at
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1 their lower portion. When the rotary gate 40 is
assembled, it may or may not contain the large bore
extension 52 and the small bore extension 54 as shown.
The opposed refractory plates 25 and the nozzles 45, 48
are securely mounted into plate within the metallic case
41 to thus define the rotary gate 40. As pointed out
earlier, the type oE ceramics as well as the size of the
bore of nozzles 45, 48 can be preselected for the
particular pouring conditions. In addition, a large bore
extension and small bore extension 52, 54 may be secured
independently interiorly of the nozzle case 50 and locked
by means of the extension lock 51 because, as shown, each
of the extensions 52, 54 is provided with a lock undercut
55, and a lock shoulder 56 which finds itself positioned
above the extension lock 51 of the nozzle case 50 and
rotate it until engaging the lock stop 58. ThuS each of
the extensions 52, 54 may be removably secured beneath
the permanently installed nozzle 45, 48, either
immediately prior to use, at the time of shipment, or
during the course of use based upon the amount of erosion
or other damage which may occur to the extension.
Large refractory parts when used in sliding gate
valves, are difficult to produce effectively from the
standpoint of maintaining uniform refractory quality
throughout the pressing that forms the partO It is
contemplated by the present invention, that this problem
can be reduced by producing the part as two smaller
sections which are ultimately assembled into the finished
part. This achieves a better finished product when
evaluated as to uniformity of quality. In addition,
because the two smaller sections are used for the basic
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,
1 refractory, nozzle inserts can be locked between the two
sections. The nozzle inserts into plates (whether top
plates or sliding gates) are normally cemented or
press-fitted into an opening provided in a refractory
plate. The walls of both the insert and the opening are
smooth, which makes pos.sible relative axial movement
between the two members. When such movement occurs, the
smoothness of the sliding surfaces of the top plate and
gate plate is disrupted thereby permitting the
possibility of metal leaking into the interface which
requires replacement of the plates. This problem is
avoided in the described arrangement, since a mechanical
lock is provided to prevent relative axial movement
between the plate and the insert. Further to be noted in
the following detailed description, drawing reference to
Figure 3, is that the nozzle insert extends above the
upper surface of the top plate into the interior of the
safety nozzle 15, thereby sealing the same between the
top plate nozzle and the working nozzle 14. The frame is
recessed at 33 to accommodate the extended axial length
of the plug 35.
SINGLE NOZZLE_EMBODIMENT
As shown in Figure 8 a single nozzle rotary gate 80
plate (not shown) can be fabricated having only one
teeming opening 81. This permits the use of larger bores
within a given outside configuration or even in an
existing valve. As an example the illustrated single
hole gate 80 may have a nozzle as large as 7 inches and
yet it fits within the outer dimension of a two hole gate
that is limited to a maximum bore of 5 inches. The flow
rate of the 7 inch bore is twice
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that of a 5 inch bore. This increase in available flow rate
would allow application of the valve to charging ladles,
torpedo cars, and even to furnaces.
SIX NOZZLE EMBODIMENT
The six hole gate 90 shown in FIG. 9 provides at
least two functional advantages. The use of several different
bore sizes allows uniform teeming rates when the ladle is full
as well as when it is nearly empty without throttling or at
least with minimal throttling. Metalurgical quality of steel
ingots is adversely effected by both non-uniform teeming
rates and by the flaring stream that results from throttling.
Too fast or too slow a fill rate is detrimental to ingot
quality. A flaring stream re-oxidizes during teeming resulting
in ingot inclusions and a flaring stream sticks to ingot
mold sidewalls and results in poor surface quality. Continuous
cast steel also suffers from re-oxidizing due to a flariny
stream and absolutely demands a constant teeming rate in
order to maintain constant withdrawal rate from the mold.
The use of multiple bores provides more "shut-offs"
between plate changes saving time and permitting teeming of
more smaller ingots from a given ladle size.
As illustrated in FIG. 9, the six hole gate has two
series of threé bore sizes. As an example these are 2 1/2"
91, 1 3/4" 92 and 1 1/4" 94. The 1 3/4" inch allows flow
rates of one half the 2 1/2 inch and the 1 1/4 inch would
provide flow rates of one half the 1 3/4 inch or one quarter
- the flow rate of the 2 1/2 inch.
MATERI~L'i
The preferred material for the plates is a highly
shock-resistant refractory that also has a high abrasion
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resistance. Generally this is an 85 to 95% alumina refractory
body made from tabular alumina. The materlal used for the
nozzle in the top plate must be highly erosive resistant.
The top plate assembly shown keeps the amount of material in
the orifice nozzle to a minimum which permits the economical
use of some of the more expensive refractory materials such
as the zirconium oxides.
The material used for the gate nozzles also must
be highly abrasion resistant. The thru bore design shown
allows the nozzle, which is all that is exposed to the flowing
stream, to be of a different material than the plates.
The assemblies illustrated allows use of different
materials in the top plate nozzle and gate nozzles. These
can be varied to better accomodate the steel to be teemed.
A few examples of this are outlined below.
Aluminum killed steels are soft and do not abrade
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refractories but rather they tend to precipitate aluminum
oxide which adheres to the refractory and restricts the
flow. A low alumina, clay type refractory can be used for
these grades as they are less expensive, better insulators,
resist aluminum oxide deposits and the fact that they are
poor from an errosion resistant standpoint is not a disadvantage
with these grades of steel.
Rimming grades of steel contain much dissolved
oxygen and they chemically errode many refractories. In
some cases it has been found that magnesium oxide or "basic"
refractories resist this action best.
High manganese grades of steel and particularly
those having high manganese and high carbon are highly
abrasive and "acid" refractories of the high alumina type or
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even zirconium oxides resist this best~
The generally preferred materlal for the gate nozzle
extension is a good insulator to reduce "bugging" or freezing
of the teeming steel on the edge of the extension orifice.
When this occurs the stream is deflected and flares badly
causing an increase in reoxidation. Most good insulators
are not highly errosion resistant so extensions of these
materials need to be replaced before the other refractories
of the gate and top plate. The bayonet attachment allows
this to be done easily and quickly.
When a submerged pouring tube or long tube is used,
it is attached in the same manner and then lowered so that
its discharge end extends into the molten pool below. These
tubes are generally made of one of two materials. Fused silica
tubes are used with aluminum killed and other low abrasive
steels as they have good shock resistance so that they do not
require preheating and they minimize aluminum oxide deposit
problems being non-alumina and an excellent insulator. Alumina
graphite tubes must be used with highly abrasive steels such
as high manganese, high carbon grades even though they require
preheating before installation.
T~E METHOD
The method of the present invention, as summarized
above, is directed primarily to a sequence of steps whereby
identical refractory plates 25 can be employed with a top
plate metallic case 41 and a rotary gate metallic case 41 to
economically fabricate the replaceable parts of a rotary gate R.
The economies are achieved by means of utilizing a single
identical refractory plate 25 to define the interface
between the top plate 20 and the rotary ga-te 40. By selecting
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a particular type top plate nozzle 30, the top plate nozzle
30 may have a pour opening 31 in accordance with the use in-
tended, as well as a ceramic material with the erosion, con-
ductivity, and other properties desired for the operation.
Similarly, the top plate plug 35 may be formed of the ceramic
of the choice for the particular pour. Once the selections
of the top plate nozzle and top plate plug are made, the parts
are secured in place within the metallic case 21, mortared
for a secure connection therewith, and then desirably ground
to provide a smooth surface at the interface between the top
plate 20 and the sliding gate 40. Further as pointed out
above, both the top plate plug 35, and the top plate nozzle
30 extend upwardly through the nozzle access ring 37 and
plug access ring 39 for their ultimate secured relationship
with the mounting plate 18 as shown in FIG. 3.
The method of forming the rotary gate 40, as illu-
strated in FIG. 7, contemplates using the same identical
refractory plates 25 as used with the top plate, and thereafter
selecting nozzles 45, ~8 with the appropriate bore or pouring
diameter, as well as material, for the intended operation.
Thereafter the two top plates 25 are pressed into position
to lockingly engage the nozzles 45, 48 and the same are
mortared into the metallic case 41. Thereafter, different
extensions 52, 54 may be positioned in the nozzle case 50,
again with the pour diameter or through bore being pre-
selected for the particular operation involved, as well as
the material.
The method of forming a single nozzle rotary gate
and top plate, as shown in FIG. 8, is essentially the same.
When more nozzles are employed, such as six as shown in FIG.
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9, a second diamond shaped section 95 is employed but used
in opposed relationship to i-tself agalnst the locking flats
95.
Often it is desirable to use a submerged pour tube
or nozzle. They can be used in conjunction with a short tube or
nozzle such as in the two nozzle embodiment.
In the event the steel becomes frozen in the pouring
vessel, the short tube is positioned in the operating configu-
ration, and an oxygen lance applied thru the short tube in
order to open or start the pour. Thereafter, the submerged
tube is rotated into position, and pouring continues. It is
virtually impossible to oxygen lance through a long, submerged
tube, some such tubes being as long as 4 and 5 feet.
The extension can be replaced during a pour in the
shutoff condition by using a remote handling device, the
operative portion of which is essentially a screw extractor.
The extensions are preferably mortared in with a non-binding
type clay mortar which renders removal and replacement easy.
Also, as shown in FIG. 9, it is possible to fabricate
the gate plate of three or more pieces, thereby having more
than two depending nozzles. As the number of noæzles are
increased, naturally the shutoff distance upon rotation is
decreased, and there comes a time, depending upon the radius
of rotation where further pouring tubes become impractical.
Nonetheless, the invention is capable of such variations.
THE METHOD OF SEALING
A further problem addressed by another aspect of
the present method arises from the warpage of the back plate
18 of the rotary valve assemblage "R". In virtually all
Ivalve installations, even though the steel back pla-te behind
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the stationary top plate is some three inches thick, at
temperatures of 900F, this temperature is some 300 above
the "creep" temperature for steel. Accordingly during
successive pours, the back plate or steel casing 10 of the
vessel, as well as the back plate 18 of the valve is inclined
to warp at a rate and intensity which is not predictable. Nor
can this be controlled adequately by known forms of coolingO
To accomodate the above problem, it is contemplated
that the rotary valve top plate 20 which is stationary, as
well as the rotary gate 40 are spring loaded in such a fashion
as to cause a deflection corresponding mutually with the
deflection or warpage of the back plate, to the end that the
interface between the two ceramic members will be in constant
fluid tight pressure relationship. This method is carried
out through the means of a plurality of load pads 60, distri-
buted as shown best in FIG. 5 (in conjunction with FIG. 3)
in such a manner that they surround the nozzles, as well as
uniformly or dispursed over the ceramic members.
Although particular embodiments of the invention
have been shown and described in full here, there is no inten-
tion to thereby limit the inven-tion to the details of such
ernbodiments. On the contrary, the intention is to cover all
modifications, alternatives, embodiments, usages and equivalents
of the subject invention as fall within the spirit and scope
of the invention, specification and the appended claims.
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