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10,1946.
A. L, SIMlSbN ET AL
’
' 2,407,295
APPARATUS FOR PRODUCING FIBR‘QUS GLASS
Filed March 26, ' 1942‘
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Sept. 10, 1946.
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A. L. sin/"SON ETAL
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2,407,295
APPARATUS FOR PRODUCING FIBROUS GLASS
Filed March 2e,_ ‘1942
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Patented Sept. 10, 1946
2,407,295 _
UNITED STATES PATENT OFFICE
‘ APPARATUS’ FOR PRODUCING FIBROUS
"
GLASS
'
Allen L. S‘imison and Ed Fletcher, Newark, Ohio,
assignors to Owens-Corning Fiberglas Corpora
tion,,Toledo, Ohio, a corporation of Delaware
'- = Application March 26, 1942, Serial No. 436,236
9 Claims.‘ (01. 49-55)
1
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This invention relates 'to the manufacture of
glass ?laments and more particularly to improved
apparatus for feeding molten glass. or similar
heat-plasticized material in the attenuation of
?laments.
.
either above or below the devitri?cation point
'
In the manufacture ,of glass ?laments glass
making materials are melted‘in a container‘or
receptacleconventionally‘in the form of a trough
having metal Walls and bottom and provided in
of the glass. Holding‘the entire supply body at
the attenuating temperature 0r cooling it slowly
from ‘a higher temperature to the attenuating
temperature entails the danger of devitri?cation.
If, however, the supply body is held at ‘a temper
ature well above the ‘devitri?cation temperature
its bottom wall with an ori?ce or ori?ces from
which. the glass ?owsin the form of. ?ne streams.
In the production of ‘ glass ?laments by atten
uating a stream of molten glass ?owing through
2
solution of the ingredients of the glass and elims
inate all striae, cords and orientations of ingr‘ee
clients. For many glass batches‘the desired at~
tenuating temperature is relatively near‘ and
7 and then at the ori?ce reduced quickly to the
attenuating temperature, devitiri?cation is pre
vented.
a
shown
smallinori?ce
UnitedStates
in a molten
Patent
glass
No.container,
2,291,289 of
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It is an object of the present invention to pro
July 28, 1942 to Slayter and Thomas, it is desir~
vide apparatus for obtaining accurate temper“
able to have accuratecontrol of the temperature
of the glass in the region of attenuation. This is
ature controlof the molten glass ‘in the attenu
ating zone and to assure rapid'reduction "of the
true whether‘ the attenuation is effected me
temperature‘of the glass in‘ the. neighborhood of
chanically, for instance, by employing a rotating 20 this zone to the desired attenuating temperature;
drum to attenuate the ?laments and-on which
It is an ancillary object to cause the temperature
the ?laments are wound, or whether the streams
of the'glass in the region of attenuation" to be
are attenuated by tractively engaging them with
dependent mainly upon the temperature‘ of ‘the
a gaseous blast moving‘in the direction of stream
supply body‘and upon stable ?xed factors and
flow. Attenuation of'glass ?lamentsbymechan
not upon applied cooling means, thereby permit
ical means in the form, of a Winding drum is de-‘‘
ting regulation of the viscosity of the glass ‘being
scribed-in the United States Slayter, and Thomas
attenuated-merely by regulating the temperature
Patent No; 2,234,936 of March 18, 19.41 and by
of the supply body.
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mechanical-means in the form ‘of coacting gear
‘It is a further object of the invention to cause
shaped rotors in the United‘StatesSlayter- Pat
30 the reduction‘ in temperature at a point ‘close to
out No. 2,230,272 of February 4, 1,941. i The
Slayter and Thomas Patent No. 2,133,236 of Oc
theupoint of attenuation. The rapid reduction of
temperature in the neighborhood of attenuation
permit-s holding only a minimum quantity of
tober 11, 1938 describes theprocess'of attenu
ating glass ?laments or ?bers by a gaseous blast.
glass at the attenuating temperature, thereby
In order to‘rapidly‘produce ?ne ?bers of reg~ 35 eliminating the danger of incipient devitri?ca
ulable uniform diameter, the temperature of the
glass should 'be accurately controlled during its
It is highly desirable in the interest of greater
passage from the. supply body to the point where
and more economical production to maintain‘the
the fibers may be said‘ tojbeycompletely formed.
viscosity of the glass being attenuated sui?ciently
If attenuation takes‘vplace at too low a temper 40 low so that only a minimum tension is required‘
ature the ?bers are coarse’ and uneven on their
to attenuate each ?lament. However, in the case
tion.
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surfaces. The resistance. to‘ attenuation of glass
at low temperature-requires greater‘pulling force
ori?ces,lthe glass at thislow viscosity wets the
and
metal and flows over the outside wall of the ‘bush
consequently
the ‘ consumption
of
where the molten glass ?ows from metal-walled ‘
more
Power, and resulting-‘in the case of attenuation
by means of a drum, in such tight packing of the
ing, ?ooding the ori?ce and interrupting atten
uation therefrom. The molten glass eventually
spreads to adjoining ori?ces and ?oods them‘in
strands on the drum as to ‘interfere with their
later removaljjQn the other hand; glass at too
turn so that within a short time the operation
must be halted and the bushing cleaned. ' If the‘
high a temperature is sotrwatery ‘and ?uid as to
preclude attenuation.
Constant temperatures
metal about the ori?ce‘is maintained su?iciently
cool to prevent ?ooding, it has been discovered
that in prior bushings the glass ?owing through
are also necessary to obtain uniformity of the
product.
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The supply body of glass is preferably main
tained at a temperature higher than the desired
attenuating - temperature to facilitate complete
the ori?ce passage was of such a high viscosity
that the attenuating force necessary was unduly‘
’
increased.
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2,407,295
3
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It is a further object of the present invention
to obtain both of the above desired properties
simultaneously. The glass being attenuated is 01‘
suf?ciently low viscosity to permit attenuation
with a minimum attenuating force and the metal
surrounding the ori?ce is suf?ciently cool to pre
vent wetting thereof by the molten glass, thereby
is formed of a heat resistant precious metal or
eliminating ?ooding.
precious metal alloy and is heated by passing an
electric current through its walls.
The small streams of molten glass ?owing
through openings in the bottom of the bushing
may be attenuated into ?laments by means of a
revolving spool or drum l2 upon which the ?la
ments are wound to form a package. Interme
diate the drum and the bushing the ?laments
It is also an object of the present invention to
reduce the resistance to flow of the molten glass .10 pass over a pad I3 which is arranged to group
the ?laments into a strand and to apply a suit
through the ori?ce passage as its viscosity in
able lubricant or sizing to the ?laments. The
creases to the desired attenuating viscosity so
pad may be of any suitable type such, for instance,
that the glass may be cooled su?iciently to be
as that shown and described in the Fisher Pat
properly attenuated and to prevent ?ooding of
the ori?ce without unduly increasing the resist‘ 15 ent No. 2,224,149.
Figure 2 illustrates apparatus for attenuating
ance to movement of the glass through the ori
glass ?bers by means of a gaseous blast. This
?ce passage. More particularly, it is an object
apparatus may include a bushing 20 similar to
to reduce the rate of flow of the molten glass as
the bushing I0 and heated in like manner.
its viscosity increases. Since the viscous resist
Spaced beneath the bottom of the bushing 20
ance of a liquid is directly proportional to the 20
is a blower 2| provided with oppositely disposed
rate of movement thereof, a reduction in the rate
series of jets for directing converging gaseous
of ?ow of the molten glass lessens the effect of
blasts onto the streams of molten glass ?owing
increased viscosity.
I
from the bushing to attenuate the streams into
It is a still further object of the invention to
provide a glass feeding ori?ce from which the 25 ?bers. The Slayter and Thomas Patent No.
2,133,236 more fully discloses this method of pro
glass will ?ow under the action of gravity when
ducing glass ?bers. The ?bers, after they are
attenuation is interrupted although the ori?ce is
formed, may be deposited on a moving forami
of small size and the viscosity of the glass is suf
nous surface 24 spaced a suitable distance be
?ciently high to prevent wetting of the outer
metal walls of the ori?ce. This‘ provides for au~ 30 neath the blower.
The bushings HI and 20 are each provided on
tomatic starting of stream ?ow.
their bottom wall 25 with a plurality of tips 26
Other objects, as well as advantages, of the
projecting outwardly a substantial distance
present invention will be apparent from the fol“
lowing description.
therefrom.
In the drawings:
Figure 1 is a schematic elevational view of ap
paratus for the production of continuous ?la
ments by mechanical attenuation;
extending therethrough communicating at its
Figure 2 is a schematic elevational view of ap
Each of the tips has a passage 21
inner end with the interior of the bushing and
opening to the atmosphere at its outer end 28.
The inner end of the passage 21 is preferably
gradually converging in cross-section as shown
paratus for attenuating the ?laments by means 40 at 29 so that the molten glass is inducted in a
smooth streamline flow into the passage. The
of a gaseous blast;
converging portion of the passage directly com
Figure 3 is a longitudinal vertical section of
municates with a straight portion 30 which in
the bushing of the present invention on a greatly
turn is in communication with a straight sided
enlarged scale and partly broken away;
Figure 4 is a sectional view on a like scale of 45 enlarged passage 3 I. At its point of meeting with
the passage 30, the passage 3| is preferably
a bushing tip illustrating a modi?ed form; and
rounded as at 32 to permit the glass to flow into
Figures 5 and 6 are similar views illustrating
the larger passage without the formation of eddy
further modi?cations.
currents and to eliminate any pockets where the
The present invention provides an improve
glass may be quiescent.
ment of the conventional glass melting unit or
The walls surrounding each passage 21 prefer
feeder that is in the form of a receptacle or con
ably gradually decrease in thickness from the
tainer for the molten glass and having ori?ces
bottom 25 of the bushing to the point where the
in a wall thereof through which the glass ?ows
passages 30 and 3| join. At this point the wall
in the form of ?ne streams. The construction
of the container is such that difficulties hereto 55 is abruptly reduced in thickness and then again
gradually decreases in thickness from the round
fore encountered are eliminated. More partic
ed portion 32 to the outer end 28 of the tip.
ularly the feeder itself is of conventional form
This tapering cross-section of the wall facili
having side walls preferably of metal, and a me
tates gradual cooling of the molten glass ?owing
tallic bottom wall provided with tips or nipples
having passages for the molten glass extending 60 through the passage in two ways. It lessens the
centrally therethrough. In the present case the
amount of heat conducted by the walls from the
passages are provided at their outer ends with
bushing to the end 28 of the tip or nipple and
enlargements which cooperate with. a novel con~
also, by virtue of the thinner wall adjacent the
struction of the walls of the tips to control the
end 28, the rate of dissipation of heat from the
temperature, viscosity and rate of ?ow of the 65 molten glass as the glass approaches the lower
glass to assure uninterrupted e?icient operation
end of the passage is increased.
of the apparatus.
The molten glass in the bushing is preferably
at a temperature several hundred degrees above
Referring to Figure 1 of the drawings, a con
the attenuating temperature and ?ows into the
tainer or receptacle I!) for holding a supply of
molten glass, called a bushing, is provided for 70 passage 21 and begins to cool as it moves away
feeding molten glass in a multiplicity of small
from the bottom of the bushing. It cools but a
streams from its bottom wall. Glass already
small amount, however, by the time it reaches
molten may be fed into the upper end of the
the passage v3i! so that it ?ows through said pas
bushing, or cullet or raw batch may be fed there
sage at a viscosity lower than the attenuating
into and melted in the bushing. The bushing 75 viscosity. As the molten glass ?ows into the en
2,407,295
5
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larged passage 3|, its rate of cooling is acceler
sage 38 in the tip, which controls to large extent
ated because of the fact that here the wall of the
the rate of flow of molten glass through the tip,
tip is abruptly reduced in thickness and also be
may, if desired, be of the same size regardless of
cause the enlarged passage 3| slows down the
the size of ?lament being, attenuated within
rate of flow of the‘molten glass to increase the Cl reasonable limits and the desired regulations, of
rate of cooling. As the molten glass continues
?lament size may be effected solely by varying
its movement through the passage 31 it continues
the speed of attenuation. However, to prevent
to cool at the increased rate so that by the time
going to ine?icient very low speeds, it is desirable
it reaches the lower end of the tip it is at the
to increase the diameter of the passage 30 for the
desired attenuating temperature and proper vise 10 production of larger size ?laments. ‘The size of
cosity. The rate of cooling of the glass as it
the passage 3| may remain substantially the
moves through the passage 3| is greater than the
same, the only di?erence in operation being that
rate of cooling in the passage 30 so that the glass
the slightly larger passage 3!! permits a higher
is rapidly cooled in the neighborhood of the
rate of ?ow of molten glass into the passage 3|
devitri?cation point to minimize the danger of
with a consequent greater amount of glass going
devitri?cation.
into the ?lament.
‘
The enlarged passage 3| serves a further pur
The length of the passage 30 also governs the
pose in that the body of molten glass therein
rate of flow of the molten glass and it must be
constitutes a reservoir of molten material so that
proportioned to obtain the proper rate of ?ow,
upon slight momentary fluctuations in operating
20
variations in its length perceptibly affecting the
conditions, the attenuation will not be disrupted.
Thus, an instantaneous chilling of the tip will
not affect the relatively larger body of glass in
the passage 3: sufficiently to stop attenuation.
Also, localized bodies of glass at higher tempera 25
‘
tures ?owing into the larger passage 3! will be,
rate of now of the viscous glass therethrough.
to a large extent, equalized.
-
The enlarged passage 3! is of a diameter and
length so proportioned as to provide the desired
temperature drop of the molten glass flowing
therethrough and to hold a proper quantity of
molten glass.
With bushing ori?ce passages heretofore em
Although the manner in which the tip of the
ployed cessation of- attenuation of the stream
present invention acts to minimize the attenuate
flowing from the ori?ce caused the glass therein
ing force required and at the same time prevent 30 ‘to stop ?owing, apparently because the glass at
flooding of the bushing tips is not completely
the lower end of the ori?ce was quickly cooled
understood, it may be that the enlarged passage
by the metal walls when it ceased to be drawn
3! permits a differential in temperature between
out by the attenuating force. The glass at the
the central portion of the molten glass in the
end of the ori?ce was thus too cool and viscous
passage 3| and the outer portion of such glass
adjacent the wall of the passage. Thus the glass
toward the center is of a su?iciently low viscosity
to drop from the ori?ce under the action of grav
ity“ Operation could be started again only by
initiating flow from each ori?ce by means of a
to require only a minimum of tension to attenuate
pick. This was a time-consuming operation and
it while the glass adjacent the wall of the pas-1
greatly reduced the eiiiciency of the operation.
sage and the metal of the Wall are at sufficiently 40
The ori?ce passage of the present invention
low temperatures to prevent the glass from wet
overcomes this difficulty by causing automatic
ting the metal and ?ooding the tip. A straight
starting of the ?ow of molten glass upon inter
passage does not provide the same results, which
ruption of attenuation. As the stream flows from
may be due to the fact that a. straight passage of
the ori?ce it need only be directed to the attenu
su?icient diameter to ‘provide the required tem
ating means and the operation resumed.
perature gradient transverse to the direction of
This effect of the present ori?ce passage is be
?ow of glass permits too great a flow of glass, so
lieved due to the fact that the lower passage of
increased diameter results in a higher tempera
ture gradient of the molten glass lengthwise of
the passage. Upon interruption of attenuation
and cooling of the molten glass at the lower end
of the passage, flow ceases, but the heat of the
glass in the narrow passage directly above the
enlarged passage is quickly communicated to the
glass at the lowerend of the ori?ce pass-age and
flow of the glass is automatically resumed.
glass to attenuating viscosity takes place in the
The modi?ed form of tip illustrated in Figure
enlarged passage 3!. The present invention
4 employs a passage I30 ending in an enlarged
realizes both a minimum attenuating force and
passage l3l at its lower end of frusto~conica1
a complete freedom from flooding.
,
60 form, the lower end of said passage forming a
It has been discovered that for a given tem
sharp edge I50 with the outer wall of the tip.
perature the ?laments attenuated from the mol
This modi?ed form of passage operates in a man
ten glass flowing through the tips vary in size
ner similar to the preferred form of the inven»
with the rate of attenuation. At normal operat
tion to accurately control the temperature and
ing temperatures the relation of speed of attenu
viscosity of the molten glass therein and prevent
ation to the size of ?lament attenuated is such
flooding of the tip.
that the quantity of glass pulled always remains
The modi?ed form illustrated in Figure 5 is
substantially the same. This does not always
similar to the preferred form of the invention ex
hold true at lower temperatures where sometimes
cept that the passage 229, the passage 23c and
increase in the pulling rate may actually cause 70 the passage 2-3! merge into each other more grad~
an increase in the amount of glass pulled and
uallyand the entire passage in the tip has a
result in coarser ?bers. However, at higher tem
smoothly curved interior wall.
peratures, the higher the rateof pull, the smaller
“Figure 6 illustrates a modification operative to
is the resulting ?lament.
V
obtain the more important objects of the present
that regulation of attenuation is difficult and the
increased quantities of glass tend to ?ood the
ori?ce. If the glass in a straight passage is
maintained at a temperature sufliciently low to
reduce the flow, then it is found that the required
attenuating force is unduly increased. In the
present case, the‘ narrow passage 30 controls the
rate of flow of the molten‘ glass while at a high
temperature and the increase in viscosity of the
' We have found that because of this the pas
invention and which lends itself to being formed
2,407,295
7
by a simple die operation. With this form the
tip may be formed ?rst with straight sides and
then a wedge forced into the outer end of the tip
to flare the walls of the tip and provide the illus
trated diverging contour of the passage 321.
The present invention has the advantage that
it accurately controls the temperature of the
8
surrounding said passage decreasing progressively
in the direction of flow of glass through said ori
?ce passage, whereby a stream of molten glass
of controlled viscosity is flowed from the supply
of glass in the container.
5. In apparatus for forming glass ?bers includ
ing means for attenuating‘ streams of molten
glass to ?lamentous form, comprising, a con
molten glass to permit e?icient attenuation and
ta'iner for molten glass having a metal nipple pro
prevents ?ooding of the tips without the need
for exterior cooling means such as a draft of air 10 J'ecting outwardly from a wall thereof, an ori?ce
directed toward and impingingupon the tips.
passage extending centrally through said nipple
and communicating at its inner end with the in
terior of the container and opening at its outer
end to the atmosphere, and a straight-sided
many more ori?ces in any desired grouping or
arrangement.
I
15 channel in said passage disposed substantially
medially of its length, and a second channel
Various modifications may be resorted to with
greater in cross-sectional area than said ?rst
in the spirit and scope of the appended claims.
named channel and connecting said ?rst-named
We claim:
channel with the outer end of said nipple, the
1. Glass ?ber forming apparatus by which
streams of molten glass are attenuated into ?ne 20 thickness of the wall of said nipple surrounding
said passage decreasing progressively in the di
?bers, comprising a receptacle for the molten
rection of now of glass through said ori?ce pas
glass provided with a metallic bottom, nipples
sage throughout the combined lengths of both
projecting downwardly from said bottom and
said channels, whereby a stream of molten glass
having metallic walls integral with said bottom to
permit heat to flow from said bottom into the 25 of controlled viscosity is flowed from the supply
of glass in the container.
walls of said nipples, and a passage extending
6. In apparatus for forming glass ?bers includ
through each of said nipples and communicating
ing means for attenuating streams of molten
with the interior of said receptacle at its upper
glass to :tilarnentous form comprising, a contciner
end and opening at its lower end to the atmos
phere, a straight-sided channel in said passage 30 ~for molten glass having a metal nipple project
ing downwardly from the bottom wall thereof, an
intermediate’ the ends thereof, and a second
ori?ce passage extending centrally through said
channel greater in cross-sectional area than said
nipple and communicating at its upper end with
?rst-named channel and connecting said ?rst
the interior of the container and opening at its
named channel with the lower end of said nipple.
lower end to the atmosphere to ?o-w a stream of
2. Glass ?ber forming apparatus by which
molten glass from the supply in the container,_
streams of molten glass are attenuated into ?ne
said passage through the nipple being formed
?bers, comprising a receptacle for the molten
at its upper end with an inwardly and down
glass provided with a bottom wall. nipples pro»
wardly tapering portion, said tapering portion
jecting downwardly from said bottom wall, an
ori?ce passage extending through each of said 40 opening at its lower end into a substantially
straight-sided channel, and an outlet portion of
nipples and communicating with the interior of
said ori?ce passage greater in cross-sectional
said receptacle at its upper end and opening at
area than said straight-sided channel and ter~
its lower end to the atmosphere, said passage
minating at the lower end of said nipple, the wall
being formed at its upper end with an inwardly
Because of this, the tips may be more closely
spaced and the bushing may be provided with
and downwardly tapering portion, said tapering
‘ of said nipple decreasing in thickness progres
sively throughout the length of said nipple.
portion opening at its lower end into a substan
7. In apparatus for forming glass fibers, a con
tially straight-sided channel, and an outlet por
tainer for molten glass, a metal nipple projecting
tion of said ori?ce passage greater in cross-sec
downwardly from the bottom wall thereof and
tional area than said straight-sided channel and
located beneath said straight-sided channel and 5%) arranged to permit the passage of currents of
air therearound, said nipple having a passage
terminating at the lower end of said nipple.
therethrough communicating with the interior of
3. A container for molten glass for feeding the
said container and terminating in a downwardly
glass in a small stream to be attenuated into a
facing ori?ce through which the glass is adapted
?ber, having a metallic bottom wall and a feeding
to ?ow as it is attenuated, said passage formed
passage in the bottom wall in the form of a
with a restricted portion substantially medially
hollow nipple integral with said bottom and
of its length, the wall of said nipple beneath said
opening at its outer end to the atmosphere, said
restricted portion being of substantially reduced
passage being so proportioned as to feed the
thickness.
molten glass at the rate at which it is formed into
8. In apparatus for forming glass ?bers by at~
fibers, and a channel in said nipple at the outlet 60
tenuating a stream of molten glass to ?lamentous
end of said passage of greater cross-sectional
form comprising, a container for the molten glass,
area than said passage, the lower portion of said
a metal nipple projecting downwardly from the
nipple in the region of said channel having a
bottom wall thereof and arranged to permit the
reduced wall thickness.
4. In apparatus for forming glass ?bers includ 65 passage of currents of air therearound, said nip
ple having a passage therethrough communicat
ing means for attenuating streams of molten
ing with the interior of said container and ter
glass to ?lamentous form comprising, a container
for molten glass, having a metal nipple projecting
minating in a downwardly facing ori?ce through
which the glass is adapted to ?ow as it is at
extending centrally through said nipple and com 70 tenuated, said passage formed with a restricted
portion located below the juncture of said nipple
municating at its inner end with the interior of
with the bottom wall of the container, and the
the container and opening at its outer end to
portion of said passage contiguous to the ori?ce
the atmosphere, a straight-sided channel in said
being provided with a portion of increased cross
passage disposed substantially medially of its
sectional area, the wall of said nipple surrounding
length, the thickness of the wall of said nipple
outwardly from a wall thereof, an ori?ce passage
2,407,295
9
10
said passage progressively increasing in thick
wall to permit heat to ?ow from said Wall into
the sides of said nipples, and a passage extending
ness in the direction of flow of glass through the
passage and abruptly decreasing in thickness at
a point below said restricted portion.
7 through each of said nipples and communicating
at its inner end with the interior of said re
ceptacle and opening at its outer end to the at
9. Glass ?ber forming apparatus by which
mosphere, the walls of said passage decreasing
streams of molten glass are attenuated into ?ne
?bers, comprising a receptacle for the molten
in thickness at the outer end of the nipple.
glass provided with a metallic wall, nipples pro
jecting from said wall and having metallic sides
ALLEN L. SIMISON.
connected in heat-conducting relation with said 10
ED FLETCHER.
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