Note: Descriptions are shown in the official language in which they were submitted.
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.Ti~l~ of ~h~ Inventio~
BLAS~ FURNACE COOLIN~ ~RR~NGEM~
ield of the Invention
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~ he present in~ention relates to ferrous metallurgy
and more particularly to furnace cooli~g arrangsment~0
he invention may be employed with particular
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ad~anta~e for cooling hearths, boshe ~ a~d stack3 o~
blast ~urnaces.
The problem of enhancing the efficiency o~ cooling
the blast fur~ace portions expo~ed to the most extensive
heating i8 comparatively old, and despite numerous at- :
temps directed to the solution thereo~ has not been adeq-
uately solved up till now. ~his has been evidenced by
grave accidents to blast furnace~ which tooX place in a
number of indu~trically developed countrie~ ~or the laat
~ive year3~ Some of these accidents involved lo~a o~ huma~
lives, a~d the total damage to industrial enterpriae~
amounted to se~eral million~ o~ dollar~ All the abo~e
accidents were due to inef~icie~cy in cooling of a ~urna-
ce ~hell, which in ca~e of a lining burnout resulted in
a local melting of ~ur~ace cooler~ and the shell a~d i~
liquid metal breaki~g out ~rom the blast furnace.
2. Description of the Prior Art
.
~o~cool the lower portion of a blast furnace stack
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and bosh, ther~ i~ still utilized a water cooling ar-
rangement co~prising box-like cooling elements dispo~ed
in vertical row3 between a furnace shell and lini~g a~d
connected through a 9upply pipeline and a take-o~ pipe-
line to a proces~ water ~ain and to a cooling medium
source as di~closed in US Patent ~o. 3,628,509 and in
FRG Patent No. 290419339.
- In intensi~ièd iron making process9 ~or in~tance
with oxygen blast, at elevated pressure in a furnaceg and
at a large volume thereof the box-like cooler~ fail to
provide ef~ective heat remo~al. ~he box-like cooler~ ara
built in the lining, and as the latter breaks down they
go out o~ action as well~ ~nother disadvantage o~ the ar-
ran~ement under consideration consi~t~ in that the boæ;
-like coolers ensure but a local cooling. ~d ~inallyg
it i8 impos~ible to provide for reliable tightne~s in
those ~ections of a ~urnace ~hell where the box~like cool-
ers are built in.
In cooling a hearth a~d a hearth bottom of convent-
ional bla~t furnace~, u~e is at pre~ent made o~ the above
arrangement in combination with cooling plates disposed
in an a~nular s~ace be~ween a ~urnacs shell and a lining~
In some cases, -the hearth and the hearth bottom ma~
be cooled by watering ~he ~urnace ~rom outside~ in addit
ion to employing cooling plate~.
Provided tha-t the linirlg is undamaged~ the thermal
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load~ imposed on the cooling plates are not high and the
arrangement operates normally~ In the e~ent o~ a damaged
li~ing, the arrangemen~ fail~ to provide ~or a suffi-
ciently inten~ive removal o~ heat. Uxlder these condition~,
there arises a possibility o~ local melting of the cool-
ing plate~ hen the liquid iron comes i~to contact with
the cooling water, an explosion occurs which results in
a destruction of the ~urnace shell~ As calculations ha~e
shOEwn, the liquid iron can be preYe~ted ~rom brea~ing out
o~ the furnace through the cooling members only i~ the
velocity of the cooling water within the arrangement i9
not lower than 8 to 10 m/sec. Such being the case, the
. cooling o~ the ~urnace bottom portion only require~ an
enormous amount o~ water9 namely ~rom 3000 to 4000 m3/h
at a pressure ~rom 10 to 15 atm. It will be understood
that pumps o~ the above capaci-ty are to be provided with
power~ul drives, and hence the power con~umption o~ th~
: arrangement is extr0mely high~ .
'~ith these consideration~ in view, more promising
proved to be an arran~ement o~ evaporative cooling com-
prising a cooling screen ~ormed by vertically arranged
rows of plate3 provided with series-connected internall
ducts co~municating vertically and con~ected through sup-
ply pipelines and take-off pipelines with drum separators
aa disclosed i~ FRG Patent No. 1~9317957, Cl. 18 a - 7/1iO~
The internal duct~ o~ each plate are di~posed in one
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and the ~ame plane and form natural circulation circuits
with a respective drum separator. In operation~ the cool-
ing water within the internal ducts o~ the plates become~
heated to a boiling point and flows into the drum ~epar-
ator wherein liquid phase a~d steam phase are separated
from each other and wherein a partial steam condensation
occurs. The difference in the specific gravity of a steam-
-and water mixture in the take-of~ pipeline a~d a cooled
water in the supply pipeline ia responsible for a ~atural
repeated circulation. An obvious advantage o~ -the evapor-
ative cool~ng arrangement co~sists in a comparatively in-
tensified circulation o~ a cooling a~ent without an~
pumps and additional power consumption.
It will be understood that the reliability of the
svaporative cooling will be the higher -the more circul- :
ation circuits are provided ~ithin the plates o~ the cool-
i~g screen a~ disclosed in US Patent No. 3~7049747. Ac~
cording to the specification the internal ducts of each
plate are arranged in two planes, ~hich provides for a
more efficient removal of heatO
However, in the event of liquid metal reaching the
plates o~ the cooling screen throuOh a damaged lining~
the arrangement under consideration does not provide for
sufficient heat removal either~ which ia due to the fact
that a water velocity withi~ the natural circulation
circuit~ should be 8 to 10 m/sec, i.e. the value which
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practically cannot be attained~
Kno~n in the art i~ a blast furnace cooling arran~c-
ment w~ich combine~ the advantage~ o~ the above arra~e-
ments o~ water cooling and evaporative caoling a~ describ-
ed in US Patent ~o~ 4,061~317. This arrangement comprises
a cooling ~creen arranged in an`annular space between
a ~urnace shell and lining. ~he cooling screen is compo~-
ed of plate~ ~orming vertical rows and incorporating
series-connected main and additional inter~al ducts com-
municating vertically with each other. Both the mai~ and
the additional ducts have common inlets and outlets. Mount-
ed above the cooling 3creen are drum separators communic
ating through ~upply pipes and ta~e-off pipes with com~
mon inlets and outlets of the main and the additional
ducts in vertical raw~ of the plates and ~orming clo~ed
circuite of natural circulstio~. Through distributing
valve~ the additional ducts are connected to a proce~
water supply main and ~orm therewith a open circuit of
~orced ciroulation. The distributing val~es ara mounted
at the common inlet~ and outlets o~ the additîonaI duct~
and permit a selective connection thereof to the circuits
of ~orced circulation.
Provided the lining i~ in good ~orking order~ the
additional duct~ of the plate~ in each row are connected
to the circuit~ o~ natural circulation9 and the arrange-
ment operate~ without any extra consumption o~ powe~
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the event of a damaged lining, the additional ducts are
cut Of~ from the circuit o~ natural circulation and conn-
ected to the open circuit of forced circulation~ i.e.
to the process water supply mai~. A high velocity o~ the
process water within the additional ducts provides for
an ef~icient removal of heat from the plates located i~
the hazardous zone, thereby preventing them from breaking
down.
However, in emergency condition~ the arrangement be-
ing considered su*fers from the formation of scale de-
po~it on the interior sur~ace o~ the additional ducts.
In long~time operation, the ~cale deposit grows thicker9
whereby heat exchange between the plates and the furnace
lining is materially a~fected even at high velocitie~ of`
the proce~s water. This disadvantage may be overcome by
decreasi~g the content of æalts in the watar ~ed into the
additional ducts at a rate o~ 3000 to 4000 m3/h, but pu-
ri~ication of water in such quantitie~ i~ extremely ex-
pen~iYe and will not be co~pensated by a longer service
life of the cooling ~creen~
~ummary of the Invention
The principal object o~ the present invention is toprovide a blast f~rnace cooling arrangement which enables
a relatively small amount o~ chemically pure water to be
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used for ~eeding the additional ducts of the plates
located in a hazardou~ zone and at the ~ame time assur
e~ a high velocity of water circulationO
Another important ob~ect o~ the pre~ent invention
i3 to pre~ent the ~ormation o~ scale on the interior sur-
faces of the additional ducts.
One more object of the invention is to provide a
blast ~ur~ace cooling arrangement which ensure~ high e~-
ficiency o~ thermal protection during long-time operation
of the bla~t furnace.
An additional object of the invention i8 to improve
the reliability of the blast furnace cooling arrangement.
Still another object of the inventio~ i~ to provide
a bla~t furnace cooling arrangement whic~ e~sures a well-
-timed tranqition from natural to emergency conditions of
operation~
The~e and other ob~e¢t~ of the pre~e~t invention are
attained in a blast furnace cooling arrangement comprising
a cooli~g ~cree~ which i~ di~po~ed i~ an annular space
betwee~ a furnace shell and lining and formed by vertic~
ally arranged row~ of plates provided with serie~-conn-
ected main internal ducts and additional ducts communic-
ating vertically and having commo~ inleta and common out-
lets, drum ~:eparators mounted above the cooling Ecreen
w~ich communicate through supply pipeli~e~ and take-o~f
pipelines with the common inlet~ and the commo~ outl~ts
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of the main duct~ ~nd additional duc-ts in the vertical
rows o~ the plate~ and ~orm closed circuits of na-tural
circulation of a coolin~ medium~ circuits o~ forced cir-
culatio~ o~ the c~oling medium through the additional
duct~, and distributing valves mounted at the common in-
let~ and the common outlet~ of the sdditional duct~ in
the vertical XOW3 0~ the plate~ ~or selecti~ely connect-
ing said ducts to the circuitq of natural circulatlon a~d
to circuits of ~orced circulation, wherein, according
-to the inve~tion, each circuit o~ forced circulation i~
cloed and comprise~ a container communicating with the
common outlet o~ the additional ducts in a respective
vertical row of the plates, a heat excha~ger connected
with sa~d container, and a pump co~municating through its
inlet with the heat exchanger and through its outlet,
with the common inlet o~ the additional duc~ in the Yert-
ical row of the platesO
Thus the constructional arrangement of the circuit
of forced circulation as well as the mode o~ it~ connect~
ion with the cooling arrangement provide~ for a consider-
able flow rate and velocity o~ chemîcally pure water in
the additional dUcts~ though the amount of water in the
circuit is comparatively smallO The chemically pure water
pre~ent~ the formation o~ ~cale, lengthen~ the service
li~e and enhances the el~iciency o~ the arrangement, and
practically exclude~ accidents~
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It i~ de~irable that the containe~ of the circuit~
o~ forced circulation be dispo~ed level with the drum
separa~or~ and communicate therewith through pipelines
under and abov~ the level of the cooli~g liquid, ~hereby
*orming pair~ "containar - drum separator'~.
Due to such constructional arrangement, the drum
~eparators and the container3 are connected to a common
water level maintenance pipeli~e, have co~mon safety val-
ve~ and common level indicator3.
It i8 ~urther degirable that the pipelines connect-
ing the container~ with the drum separators be provided
with ~hut-o~f valve~ adapted to di~connect the containers
from the drum ~eparators in emergency conditions~
It i9 further de~irable that the closed circuit o~
forced circula-tion be provided with a by-pas~ pipeline
having distributing valve~ and connected i~ parallel wi~h
the ~eat exchanger. This design feature erlable~ the cir-
cuit o~ forced circulation to temporarily function in
case the heat excha~lger i~ damaged or belng replaced.
It is ~urther de3irable that the common inlet o~
the additional ducts in each vertical row o~ plate~7 con-
nected to the closed circuit o~ forced circulation be
di~po~ed level wit~ the hearth bottomy whereas the common
outlet level with the middle portio~ of the stack. Such~
a modification of the cooling arrangement is the most
dependable and provides ~or an efficient protection of
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the plate~ and the ~hell in ca~e ~ome irregularitie~
occur in the bla t furnace run.
~rie* Description of the Drawi~gs
~ or a better under3tanding o~ the nature a~d ob~ects
of the invention reference i~ made to the following de-
tailed description of its speci~ic embodiments t taken
in connection with the accompanying drawings, in which:
Fig. 1 shows a section o~ a blast furnace cooling
arran~eme~t of the present invention;
Fig. 2 shows the blast furnace cooling arrangement
viewed i~ the directio~ of arrow A of ~ig. 1 wherein the
container and the drum ~eparator are dispo~ed at one and
: the ~ame level;
Fig. 3 shows a part of the circuit of forced cir-
culation wit~ the by-pa~a pipeline, according to the in-
vention;
Fig. 4 diagrammatically ~how~ a modificatio~ of the
cooling ~creen plate provided with ~traight main ducts
and with the additional ducts in the ~orm of a coil pipe;:
~ igo 5 diagrammatically show~ a second modi~icatio~
of the cooling ~creen plate provided with the main and
additional ducts in the form o~ coil pipe~;
~ ig. 6 diagrammatically show~ a third modi~ication
o~ the cooling ~creen plate shaped as a box with parti~-
.
ion~ forming a labyrinth;
~ ig. 7 shows a sectional ~ie~ of the cooling screenplate~ taken alo~g line VII-VII of ~ig. 6;
~ igo 8 ~hows a preferred embodiment o~ the cooling
arrangement of the pre~ent inv~ntion,
Detailed D~scription o~ the Invention
Re~erring to ~ig. 1, a blast ~'urnac~ cooling arxange-
ment c~mpriees a cooling screen 1 di3po~ed in an a~nuliar
space betwesn a furnace shell 2 and lining 3. The cooling
screen 1 i8 formed by vertically arranged rows o~ plates
4 and 5. The plate~ 4 are pro~ided with main internal
ducts 6 and additional internal duct~ 7, whe~ea~ the plates
5 are provided with the main i~ternal ducts ~ only. The
main ducts 6 in a vertical row o~ the plate~ 4 and 5 are
connected in series and ~ertically communicate with each
other through con~ector3 8~ The additional ducts 7 in a
vertical row of the plates 4 are connectQd in aerles and
vertically communicate with each other through conn~ctor~
9. Thus~ the main ducts 6 i~ the vertical row o~ the
plates 4 and 5 have a commo~ inlet 10 and a common out-
let 11O The additional ducts 7 in the ~ertical row o~ the
plates 4 have a common inlet 12 and a common outlet 13
a~ well. Mounted above the cooli~g screen 1 are drum se-
parators 14 communicating with the common inletB 10 and
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12 and with common outlet~ 11 a~d 13 of the main ducts 6
and the additional ducts 7 in the vertical row o~ the
plates 4 and 5~ ~he common outlet~ 11 a~a 13 are con~-
ected with the drum separator~ 14 t~rough take-of~ pipe-
lines 15, and the common i~lets 10 and 12 are connected
with the drum separator~ 14 through ~upply pipeli~es 16.
In thi~ wa~ the duct~ and the hollow space~ of all the
enumerated element~ make up a closed circuit of natural
circulation of a cooli~g medium. ~rom the economical
point o~ view, chemically pure water i~ the most suitable
cooling me~ium.
In addition to the circuits o~ natural circulation;
there are circuits o~ ~orced circulation placed in paral-
lel therewith and connected to the common inlets 12 and
the common outlet~ 13 of the additional duct~ 7 in the
vertical row~ oP the plates 4. According to the invent-
io~, eaoh circuit o~ forced circulation i8 clo~ed and com-
pri~es a container 17 connected with the ¢ommon outlet 13
of the additional duct~ 7 in a re~pective vertical row
(or several rows forming a ~ection) o~ the plates 4~ ~he
above container 17 commu~icates through a pipe 18 with a
heat exchanger 19 which, in its turn9 communicates through
a pipe 20 with the inlet o~ a pump 21~ 2he outlet o~ the
pump 21: communicate~ with the common inlet 12 of the ad-
ditional duct~ 7 o~ a respectiv~ vertical row (or rows)
o~ the plate~ 40
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Distributing valve~ 22 are mounted at the common
inlets 12 and distributin~ valve~ 23, at the common out-
let8 13 o~ the additional ducts 7. ~he distributing ~alves
22 and 23 may be made in the form of three-way cock~ so
as t~ selectively connect the additio~al ducts 7 to the
circuit~ of natural circulation a~d to the circuits of
forced circulatio~ o~ a cooling mediumQ
The circuit o~ forced circulation i8 filled with
chemically pure water.
Reference is ~ow made to ~ig. 2 illustrati~g vertic-
al rows of the plates 4 and 5. According to a preferred
embodiment of the invention, the co~tainers 17 o~ the cir~
cuits o~ forced circulation are disposed level with the
drum separators 14, Said containers 17 communicate with
re~pective drum separators 14 throueh plpeline~ 24 and
25, thereby forming pairs "contain~r drum ~eparator"~ ~he
pipeline 24 oonnects the inner space o~ the container 17
and that of the drum separator 14 above the level o~ a
cooling m0dium contained therein~ wherea~ the pipeline 25,
u~der the level o~ the same cooling medium. The pipeli~e~
24 and 25 are fitted with ~hut-o~f valve~ 26 and 27. I~
it~ bottom portion each drum separator 14 is connected
with a water le~el maintenanc~ p1peline 28, and in its
upper portion it is provided ~ith a steam exhau~t pipe
~9 which incorporates a ~afety valve 30~ The drum separ-
a~ors 14 are ~itt~d with level indicators 31.
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Re~er~nce i~ now made to Fig. 3 illu~trating a par~
of the circuit of -forced circulation. According to the
invention there i~ provided a by-pass pipeline 34 conn-
ected in parallel with the heat exchanger 19 through di~-
tributing valves 32 and 33.
It will be understood that the blast *urnace coolîng
arrangement described above may be fi-ttcd with Yariou~ly
constructed plates. Specifically the plates 4 of the cool-
ing ~creen 1 may be con~tructed as ~hown in Fig, 4 o~
the accompanying dra~ing~. ~he main ducts 6 of -this mo-
dification may be straight pipe~ contained in the body of
the plate 4 and dispo~ed in one plane. ~he additional
duct 7 of each plate according to this modification i~
made in the form of a coil pipe.
More preferable ~or the purpose of the present in-
vention is a modification of the plate 4 ~hown i~ Figo 5
of the accompanying drawings~ According to thi~ modifi-
cation both ~ain duct~ 6 and additional duct~ 7 are coil
pipes disposed in di~fere~t plane~
Possible i~ a modi~ication of the plate 4 shown in
~ig~. 6 and 7 o~ the accompanying drawing. According ~o
this modification the plate 4 is ~ollow, and it~ inner
8paceY i8 divided into two i~ner ~pace~ by a longitudinal
partition 35. On either ~ide o~ the partition 35 the
inner ~pace~ of the plate 4 are divided by tran~ver~e
partitions 36 and 37 forming a labyrinth between an in-
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let 38 and an outlet 39.
Reference i~ now made to ~ig. 8 showing the most
reliable modification o~ the blast furnace cooling ar-
rangement wherein the comrnon inlet 12 o~ the additional
ducts 7 in each vertical row o~ the platea 4 is disposed
level with a hearth bottom 40 o* the bla~t furnace~ and
the common ou-tlet 13 o~ thc additional ducts 7, level
with the middle portion o~ a stack 410
The bla~t ~urnace cooling arran~eme~t operates in
the following way. Provided the lining 3 (Fig. 1) of
the blast furnace is undamaged9 the cooling arrangement
operates on e~aporative cooling with natural circulation.
Specifically, the cooling medlum from the drum ~eparator~
14 flows through the supply pipeline~ 16 to the common
inleto 10 and 12 of the main ducts 6 and the additional
ducts 7 in each vertical row of the plates 4. As this
takes place, the circuit o~ forced circulation i~ di~con-
nected. Flowing through the main and additional ductJ 6
and 7 the cooling medium cool~ down the plates 4 and 5
and gets ho~ up to the boiling point~ ~he ~eparation o~
the ~-team phase may occur both in the duct~ of the plates
: and in the take-off pipelines 159 ~he re~ulting ~team-and-
-water mi~ture ~lows through the common vutlet~ 11 and
13 and through the take-of~ pipeline~ 15 to the drum
separator~ 14. The di~ference in the speci~ic gravity of
the ~team-a~d-water mixture in the take-off pipeline~ 15
and the cooling liquid in the ~upply pipeli~e~ 16 provides
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for a stable natural circulation. Normal operating con-
ditions of the arrang~ment are maintained with the aid
of the water level maintenance pipeline 28 (~ig~ 2) a~d
the safety valve 30~
Provided the circuit of ~atural circulation is in
good working order, the shut-o~ valve~ 26 and 27 of ~he
modification of the cooling arra~gement illustrated in
~ig. 2 o~ the accompanying drawings are opened~ In the
event of a burning-out of the lining and liquid metal
reachin~ the cooling screen 1 (which may be indicated by
an increase in the te~persture difference of the cooling
medium, a~ increase in the temperature o~ the furnace shell
2 etc.), the -thermal load~ imposed on the plate~ 4 loca~-
ed in the hazardous zone sharply increa~es.
When a signal indicative of the burning out o~ the
lining 3 comes, the shut-of~ ~alves 25 and 27 block the
pipeline~ 24 and 259 Simultaneously therewith~ -the addit~
ional ducts 7 in respective rows o~ the pla~es 4 are dis-
connected ~rom the circuits o.~ natural circulation and
connected to the circuits o~,~orced circulation by means
o~ distributing valves 22 and 23. A~ this takes place,
chemically pure water comes from the container 17 to the
pump 21 through the heat exchan~er 19. ~he p~np 21 i~
brought into use and supplies the chemically pure wate~
at a high velocity (of the:order o~ 10 m/sec) into the
additional ducts 7 in respecti~e rows o~ the plate~ 4.
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~he ~ections Of the cooling screen which are located
ramotely ~rom the damaged area of the lining 3 con-tinue
operating normally ln the conditions o~ na~ural circul-
ationp wherea~ the plate~ located in the hazardous zone
are cooled due to a~ intensive forçed circulation of the
cooling medium.
In case the heat exchanger 19 get~ damaged~ clogged,
or ~ails to operate7 it i8 cut of~ from and the pass by
pipeli~e 34 i8 connected to the cooling arrangement with
the aid of the di~tributing val~e~ 32 (Fig. 3) and 330
The chemically pure water temporarily circulates through
the byrpa~8 pipeli~e 34 from the container 17 to the
pump 21 so a~ to allow the heat ~xchanger 19 be repaired
or replaced. In this way, the arrange~ent of the circuit
of Yorced circulatio~ provide~ for an e~icient cooling
o~ the plates 4 with a relatively small volume of che~ic-
ally pure water in emergency conditions~
~ he modi~ica-tion of the cooling arrangement illust-
rated in Fig~ 8 o~ the accompanying drawing~ make~ it
po~ible to e~ectively cool, in case o~ necessity, ~ot
only the hearth and the hearth bo-ttom but the bo~h and
the lower portion of a blast furnace stack as well.
After the campaign is over and the damaged linirlg
3 repaire~, the cooling arrangement i8 brought back to
it~ original ~tate for operatio~ i~ the conditions of
natural circulation of a cooling medium,
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While particular embodiments of the invention have
been shown and described, variou~ modi~ications thereo~
will be apparent to those skilled in the art and there-
fore it is not intended that the invention be limited to
the disclosed embodiments or to the details thereo~ and
the departures may be made there~rom within the spirit
and ~cope o~ the invention as defined in the claims.
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