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Патент USA US2407457

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Sept. 10, 1946.
2 Sheets-Sheet 1
Original Filed March 26, 1942'
1; .5" 'N'VENTPF
Sept- 10, 1946‘
Original Filed March 26, 1942
- 3.
2 Sheets-Sheet 2
“W, y MfL mvs
15:1“; _\ §_U _ .
_ _. _
Allen .13- Simiaon ‘u
BYEd Fletcher
' 2,407,455
Patented Sept. 10, 1946
Newark, Ohio,
Allen L. Simison and Ed Fletcher,
assignors to Owens-Corning Fiberglas Corpora
tion, Toledo, Ohio, a corporation of Delaware
1942, Serial No.
Original application March 26,
436,236. Divided and this application October
2, 1943, Serial No. 504,800
5 Claims. (Cl. 49-77)
This invention relates to the manufacture of
glass ?laments and more particularly to an im
proved method of feeding molten glass or similar
heat-plasticized material in the attenuation of
The present application is a division of our
copending application Serial No. 436,236, ?led
March 26, 1942.
In the production of glass ?laments by attenu
attenuating temperature or cooling it slowly from
a higher temperature to the attenuating tem
perature entails the danger of devitri?cation. If,
however," the supply body is held at a tempera
ture well above the devitri?cation temperature
and then at the ori?ce reduced quickly to the
vattenuating temperature, devitri?cation is pre
It is an object of the present invention .to pro
vide a method for obtaining accurate tempera
ating a stream of molten glass ?owing through
ture control of the molten glass in the attenuat
a small ori?ce in a. molten glass container, it is‘
ing zone and to assure rapid reduction of the tem
desirable to have accurate control of the tem
perature of the glass in the neighborhood of this
perature of the glass in the region of attenuation.
zone to the desired attenuating temperature. It
This is true whether the attenuation is effected
is an ancillary object to cause the temperature ,
mechanically, for instance, by employing a rotat 15 of the glass in the region of attenuation to be
ing drum to attenuate the ?laments and on
dependent mainly upon the temperature of the
which the ?laments are wound, or whether the
‘supply body and upon stable ?xed factors and
streams are attenuated by tractively engaging
not upon applied cooling means, thereby permit
them with a gaseous blast moving in the direc
ting regulation of the viscosity of the glass-being
tion of stream flow; Attenuation of glass ?la 20 attenuated merely by regulating the temperature
ments by mechanical means in the form of a
winding drum is described in the United States
of the supply body.
It is a further object of the invention to cause
Slayter and Thomas Patent No. 2,234,986 of
the reduction in temperature at a point close to
March 18, 1941, and by mechanical means in the
the point of attenuation. The rapid reduction of
form of coaoting gear-shaped rotors in the United
temperature in the neighborhood of attenuation
States Slayter Patent No. 2,230,272 of February
permits holding only a minimum quantity of glass
4, 1941. The Slayter and Thomas Patent No.
at the attenuating temperature, thereby elimi
2,133,236 of October 11, 1938, describes the proc
nating the danger of incipient devitri?cation.
ess of attenuating glass ?laments or ?bers by a
It is highly desirable in the interest of greater
and more economical production to maintain the
gaseous blast.
In order to rapidly produce ?ne ?bers of reg
viscosity of the glass being attenuated su?icient
ulable uniform diameter, the temperature of the
1y low so that only a minimum tension is required
' glass should be accurately controlled during its
to attenuate each ?lament. ‘However, in the case
passage from the supply body to the point where
where the molten glass flows from metal-‘walled
the ?bers may be said to be completely. formed. 35 ori?ces, the glass at this low viscosity wets the
If attenuation takes place at too low a tempera
metal and flows over the outside wall of the
ture the ?bers are coarse and uneven .on their
bushing, ?ooding the ori?ce and interrupting at
surfaces. The resistance to attenuation of glass‘
tenuation therefrom. The molten glass eventual
at low temperature requires greater pulling force
,ly spreads to adjoining ori?ces and ?oods them in
and consequently the consumption of more power,
turn so that within a short time the operation
and resulting, in the case of attenuation by means
must be halted and the bushing cleaned. If the
of a drum, in such tight packing of the strands
metal about the ori?ce is maintained su?iciently
on the drum as to interfere with their later re
cool to prevent ?ooding, it has been discovered
moval. On the other hand, glass at too high a 45 that in prior bushings the glass ?owing through
temperature is so watery and ?uid as to preclude
the ori?ce passage was of such a high viscosity
attenuation. Constant temperatures are also
that the attenuating force necessary was unduly
necessary to obtain uniformity of the product.
The supply body of glass is preferably main
It is a further object of the present invention
tained at a temperature higher than the desired
to obtain both of the above desired properties
attenuating temperature to facilitate complete sosimultaneously. The glass being attenuated is of
.lution of the ingredients of the glass and‘ elimi-v
sufficiently low viscosity to permit attenuation
nate all striae, cords and orientations ‘of ingre
with a minimum attenuating force and the metal
dients. For many glass batches the desired at;
surrounding the ori?ce is sufficiently cool to pre
tenuating temperature is relatively near and
55 vent wetting thereof by the molten glass, thereby
either above or below the devitri?cation point of
eliminating ?ooding.
the glass. Holding the entire supply body at the
It, is also an object of the present invention
to reduce the resistance to ?ow of the molten
glass through‘ the ori?ce passage as its viscosity
glass fibers by means of a gaseous blast. This
apparatus may include a bushing 20 similar to
the bushing Ill arid heated in like manner.
increases to the desired attenuating viscosity so
that the glass may be cooled suiliciently to be 5 . Spaced beneath‘ the bottom of the bushing 20
is a blower 2| provided with oppositely disposed
properly attenuated and to prevent ?ooding of
the ori?ce without unduly increasing the resist~
ance to movement of the glass through the ori
?ce passage. More particularly, it is ‘an object
The Slayter and Thomas Patent No.
to reduce the rate of flow of the molten glass as 10
2,133,236 more fully discloses this method of pro
its viscosity increases._ Since the viscous resist
ducing glass ?bers. The ?bers, after they are
ance of a, liquid is directly proportional to the
formed. may be deposited on a moving forami
rateiof movement thereof, a reduction in the
nous surface 24 spaced 9, suitable distance be
rate of ?ow of the molten glass lessens the e?ect
neath the blower.
of increased viscosity.
It is a still further object of the invention to
their bottom wall 25 with a plurality of ‘nipples
or tips 28 projecting outwardly a substantial dis
tance therefrom. The tips constitute a prelimi~
nary cooling zone through which the glass passes
before reaching the region of attenuation as will
be brought out in detail as the description pro
provide a glass feeding ori?ce from which the
glass will ?ow under the action of gravity when
attenuation is interrupted although the ori?ce
is of small size and the viscosity of the glass is
su?iciently high to prevent wetting of the outer
metal walls of the ori?ce. This provides for
automatic starting of stream ?ow.
Other objects, as well as advantages. of the
present invention will be apparent from the fol
gresses. Each of the tips has a passage 21 ex
tending therethrough communicating at its inner
lowing description.
Figure 1 is a schematic elevational view of ap- -
paratus for the production of continuous ?la
Figure 2 is a schematic elevain'onal view of ap
paratus for attenuating the filaments by means
end with the interior of the bushing and open
inner end of the passage 21 is preferably grad
ually converging in cross-section as shown at 29
25 ing to the atmosphere at its outer end 28.
_ In the drawings:
ments by mechanical attenuation;
The bushings i0 and 20 are each provided on
so that the molten glass is inducted in a smooth
streamline ?ow into the ‘passage. The converg
ing portion of the passage directly communicates
{ with a straight portion
30 which in turn is in
communication with a straight sided enlarged
passage 3|. At its point of meeting with the
Figure 3 is a, longitudinal vertical section of
passage 36, the passage 3i is preferably rounded
the bushing of the present invention on a greatly
35 as at 32 to permit the glass to ?ow into the larger
enlarged scale and partly broken away;
passage without the formation of eddy currents
Figure 4 is a sectional view on a like scale of a
and to eliminate any pockets where the glass may
bushing tip illustrating a modi?ed form; and
of a gaseous blast;
Figures .5 and 6 are similar views illustrating
further modi?cations. .
be quiescent.
The walls surrounding each passage 21_ prefer
The present invention provides a bushing for 40 ably gradually decrease in thickness from the
bottom 25 of the bushing to the point where the
feeding small streams of molten glass and hav
passages 30 and 3i join. At this point the wall
ing passages therein through which the glass is abruptly reduced in thickness and then again
?ows, so constructed as to eliminate the (hill
culties encountered heretofore. More particu
larly the bushing is provided with tips or nipples
gradually decreases in thickness from the rounded
portion 32 to the outer end 28 of the tip.
This tapering cross-section of the wall facili
the molten glass ?owing
the tips to control the temperatur , viscosity and 50
rate of ?ow of the glass to assure uninterrupted
ef?cient operation of the apparatus.
Referring to Figure 1 of the drawings, a bush
_ ing Iii is provided for feeding molten glass in a
multiplicity of small streams from its bottom
wall. Glass already molten may be fed into the
upper end of the bushing, or cullet or raw batch
may be fed thereinto and melted in the bushing. ‘
The bushing is formed'of a heat resistant precious
metal or precious metal alloy and is heated by 60
so that it ?ows through said passage
passing an electric current through its walls.
at a viscosity lower than the attenuating viscosity.
The small streams of molten glass ?owing
As the molten-glass flows into the enlarged pas
through openings in the bottom of the bushing
sage 3!, its rate of cooling is accelerated because
may be attenuated into ?laments by means of
i 2 upon which the ?la 65 of the fact that here the wall of the tip is abruptly
reduced in thickness and also because the en
ments are wound to form a package. ‘Interme
larged passage 3! slows down the rate of ?ow of
diate the drum and the bushing the ?laments
the molten glass to increase the rate of cooling.
pass over a pad 13 which is arranged to group
As the molten glass continues its movement
the ?laments into a strand and to apply a, suitable
lubricant or' sizing to the ?laments. The pad 70 through the passage 3! it continues to cool at the
increased rate so that by the'time it reaches the
may be of any suitable type such, for instance,
lower end of the tip it is at the desired attenuating
as that shown and described in the Fisher Patent
temperature and proper viscosity. The rate of
No. 2,224,149.
Figure 2 illustrates apparatus for attenuating 75 cooling of the glass as it moves through the pas
sage 3| is greater than the rate of cooling in the
passage 30 so that the glass is rapidly cooled in
the neighborhood or the devitri?cation point to
minimize the danger oi! devltri?cation.
The enlarged passage 3| serves a further pur
pose in that the body of molten glass therein con
stitutes a reservoir of molten material so that
upon slight momentary ?uctuations in operating
conditions, the attenuation will not be disrupted.
oi ?ow of molten glass into the passage 3! with
a consequent greater amount of glass going into
the ?lament.
The length of the passage 30 also governs the -
rate oi ?ow of the molten glass and it must be
- proportioned to obtain the proper rate of flow,
variations in its length perceptibly affecting the
rate or ?ow of the viscous glass therethrough.
The enlarged passage M is of a diameter and
Thus, an instantaneous chilling oi the tip will
length so proportioned as to provide the desiredv
not a?ect the relatively larger body of glass in 10 temperature
drop of the molten glass ?owing
the passage 3| su?lciently to stop attenuation.
therethrough and to hold a proper quantity of
Also, localized bodies of glass at higher tempera
molten glass.
tures ?owing into the larger passage 3| will be,
With bushing orifice passages heretofore em
' to a large extent, equalized.
Although, the manner in which the tip of the 15 ployed cessation of attenuation of the stream
?owing from the ori?ce causedthe glass there
present invention acts to minimize the attenuat
in to stop ?owing, apparently because the glass ing force required and at the same time prevent
at the lower end of the ori?ce was quickly cooled
?ooding of the bushing tips is not completely
the metal walls when it ceased to be drawn
understood, it may be that the enlarged passage
3| permits a differential in temperature between 20 out by the attenuating force. The glass at the
end of the ori?ce was thus too cool and viscous
the central portion of the, molten glass in the pas:
, sage 3| and the outer portion or such glass adja
cent the wall of the passage. Thus the glass to
to drop from the ori?ce under the action of
gravity. Operation could be started again only
by initiating flow from each ori?ce by means of
ward the center is of a su?lciently low viscosity
to require only a minimum of tension to attenu 25 ‘a pick. This was a. time-consuming operation
and greatly reduced the efficiency of the opera
ate it while the glass adjacent the wall of the
passage and the metal of the wall are atsu?i
The ori?ce passage of the present invention
ciently low temperatures to prevent the glass from
overcomes this dif?culty by causing automatic
wetting the metal and ?ooding the tip. A straight
passages does not provide the same results, which 30 starting of the ?ow of molten glass upon inter
ruption of attenuation. As the stream ?ows from
may be due to the fact that a straight passage of
the ori?ce it need only be directed to the atten- su?icient diameter to provide the required tem
uating means and the operation resumed.
perature gradient transverse to the direction of
‘ This effect of the present ori?ce passage is
?ow of glass permits too great a ?ow of glass, so
that regulation of attenuation is difficult and the 35 believed due to the fact that the lower passage
increased quantities of glass tend to ?ood the ori
?ce. If the glass in a straight passage is main
tained at a temperature su?iciently low to reduce
of increased diameter results in_a higher tem
perature gradient of the molten glass length
wise of the passage. Upon interruption of at
tenuation and cooling of the molten glass at the
tenuating force is unduly increased. In the pres 40 lower end of the passage, ?ow ceases, but the
heat of the glass in the narrow passage directly
ent case, the narrow passage 30 controls the rate
above the enlarged passage is quickly communi
of ?ow of the molten glass while at a high tem
cated to the glass at the lower end‘ of the ori?ce
perature and the increase in viscosity of the glass
passage and flow of the glass is automatically
to attenuating viscosity takes place in the en
larged passage 3 I . The present invention realizes
the ?ow, then it is iound‘that the required at
The ‘modi?ed form of the invention shown in
Figure 4 illustrates a'bushing bottom wall I25
provided with a tip I26 and having a passage
It has been discovered that for a given tem
I30 ending in an enlarged passage l3l at its‘ lower
perature the ?laments attenuated from the
molten glass ?owing through the tips vary in 50 end of_frusto-conical form, the lower end of said
passage forming a sharp edge I50 with the outer
size with the rate of attenuation. At normal op
wall of .the tip. This modi?ed form of passage
erating temperatures the relation of speed of at
operates in a manner similar to ‘the preferred
tenuation to the size of ?lament attenuated is
form of the invention to accurately control the
such that the quantity of glass pulled always re
temperature and viscosity of the molten glass
mains substantially the same, This does not
therein and prevent ?ooding of the tip.
always hold true at lower temperatures where
The modi?ed form illustrated in Figure 5 is
sometimes increase in the pulling rate may actu
similar to the preferred form of the invention
ally cause an increase in the amount of glass
including the bushing wall and tip designated
pulled and result in coarser ?bers; However, at
respectively by the numerals 225 and 226, except
higher temperatures, the higher the rate of pull,
that the passage 229, the passage 23!] and the
the smaller is the resulting ?lament.
We have found that because of this the passage ‘ passage 23|pmerge into each- other more grad-e
ually and the entire passage in the tip has a
30 in the tip, which controls to large extent the
rate of ?ow of molten glass through the tip, may, ' smoothly curved interior wall.
Figure 6 illustrates a modi?cation operative to
if desired, be of the same sizev regardless of the 65
obtain the more important objects of the present
size of ?lament being attenuated within reason
invention and which lends itself to being formed
able limits and the desired regulations of ?la
by a simple die operation. In this form the bot
ment size may be effected solely by varying the
tom wal1 325 of the bushing is provided with
speed of attenuation. However, to prevent going
to inefficient very low speeds, it is desirable to in 70 a tip 326 which may be formed ?rst with straight
sides and then a wedge forced into the outer
crease the diameter of the passage 30 for the pro
of the tip to ?are the walls of the tip and
duction of larger size ?laments. The size of the
provide the illustrated diverging contour of the
passage 3| may remain‘ substantially ‘he same,
passage 321.
the only difference in operationwbeing that the
The present invention has the advantage that '
slightly larger passage 30 permits a higher rate 75
both a minimum attenuating force and a com
plete freedom from ?ooding.
it accurately controls the temperature of the
molten glass to permit e?‘lcient attenuation and
prevents ?ooding of the tips without the need for
attenuating a stream of molten glass, the steps
of establishing a supply body of molten glass at a
exterior cooling means such as a draft of air
temperature above the attenuating temperature
directed toward and impinging upon the tips,
Because of this, the tips may be more closely
spaced and the bushing may be provided with
said body, accelerating the velocity of the stream
through a first cooling zone, then decreasing the
many more ori?ces in any desired grouping or
of the glass, ?owing a stream of molten glass from
. velocity of the stream as it approaches the region
of attenuation, and as said stream moves at de
Various modi?cations may be resorted to with-_ 10 creased velocity cooling said stream at a higher
rate of cooling than in said ?rst cooling zone.
4. In the method of producing glass ?bers by
attenuating a stream of molten glass, the steps
1. In the method of producing glass ?bers by
01.’ establishing a. supply body oi! molten glass at
attenuating a stream of molten glass, the steps of
establishing a supply body of molten glass at. a 15 a temperature above the attenuating temperature,
?owing a stream of molten glass from said body
temperature above the attenuating temperature
to the atmosphere and gradually cooling the
and above the devitri?cation temperature, ?owing
in the spirit and scope of the appendedclaims.
We claim:
a stream of molten glass from said body, acceler
ating the velocity of the stream through a ?rst
cooling zone, and then rapidly cooling said stream 20
to a temperature below the devitri?cation point of
the glass and decreasing the ?ow of the stream
stream as it moves away from said body, reducing
the velocity of the stream as it approaches the
atmosphere, and increasing the rate of cooling
of the-stream moving at said reduced velocity.
5. In the method of producing glass ?bers by
attenuating a stream of. molten glass, the steps
as it approaches the region of attenuation. ,
of establishing a supply. body of molten glass at
2. In the method of producing glass ?bers by
attenuating a stream of molten glass, the steps 25 a temperature above the attenuating tempera
ture and above the devitri?caticn temperature of
of establishing a supply body of molten glass at
the glass, ?owing a stream of molten glass from
a temperature above the attenuating temperature,
said body to an attenuating region and gradually
?owing a stream of molten glass from said body,
cooling the stream as it moves away from said
accelerating the velocity of the stream through a
?rst cooling zone, accelerating the rate of cool 30 body, reducing the velocity of the stream as it
approaches the attenuating region, anddncreasing
ing of said stream, by decreasing the velocity of
the rate of cooiing of the stream to bring it rapidly
the stream through a second zone, and increasing
to a temperature below the devitriflcation temper.
the rate of cooling over that in the said ?rst cool
ing zone,
sum 11». ?ili?SON.
3. in the method of producing glass ?bers by 35
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