CA1066895A - Method and apparatus for processing glass - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A method of forming glass fibers includes maintaining heat-softened glass at a perforated planar area of a thin metallic plate, establishing pressure of the heat-softened glass and extruding the glass by the pressure through the per-forations forming streams of glass. A stream of gas is direc-ted upwardly into contact with the perforated area of the plate for transferring heat away from the plate at a temperature lower than the temperature of the heat-softened glass adjacent the plate to promote the delivery of discrete streams of glass from the perforations without flooding of the glass at the perforated planar area, and attenuating the streams of glass to fibers. Apparatus for carrying out the aforesaid method is also disclosed.

Description

~L~66~g5 This invention relates to a method of and apparatus for processing glass and more especially to a method of flowing fine streams of glass from openings or orifices in a feeder plate under an environment and conditions wherein the individual streams may be attenuated -to continuous ilaments and the tendency for the glass to flood at the feeder plate substantially raduced or eliminated.
It has been a practice in the formation of fibers or filaments from heat-softened glass to flow a plurality of streams of glass from a supply in a stream feeder or bushing through passages or orifices provided in projections integral with and depending from the floor of a feeder, the orificed prGjections being spaced a substantial distance one from another where~y individual or discrete streams are formed which may be attenuated to filaments, the spaced apart projections tending to prevent flooding of the glass over the stream delivery section of the feeder.
In arrangements of this character for flowing a sub-stantial number of streams of glass to provide a substantial `~ number of filaments in a strand, a comparatively large stream feeder is necessary to accommodate the spacing betwe~n adjacent oriiced projections in order to prevent flooding, and in order to facilitate the formation of beads of glass which fall by gravity . - - .
with attendant trailing filaments which are manipulated by the operator to effect winding of a strand of the filaments upon a rotating collector to form a package. A stream feeder or bushing of thls character is necessarily of comparatively large size and, being fashioned of platinum or an alloy of platinum, renders ilament production expensive particularly where a large number of -fllaments are grouped in a single strand. The conventional stream feeder bushing is fashioned with a floor and walls of substantial ..
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~)66~395 thickness in order to withstand the pressure head of molten glass contained in the feeder or bushing and to facilitate accurate temperature and viscosity control of the glass. The molten glass within the feeder or bushing is at a comparatively high temperature and hence low viscosity in order that substantially uni- ~ -form streams of glass flow from the orificed projec-tions for attenuation to ~ine filamen~s of uni~orm size. While the use of spaced orificed projections depending from a feeder floor reduces the tendency for the glass to flood over the surface of the feeder, under certain conditions the glass will flood along the surface of the feeder and interrupt stream flow and attenuation. ~ -The present trend in the production of tex-tile strands of glass filaments is to simultaneously at-tenuate a large number of fine filaments from streams of molten glass and combine them into a single strand.
In order to attain an increased number of streams from a feeder, the size of the stream feeder or bushing must be increased. Many difficulties are encountered in in-creasing the feeder size, such as the tendency for the floor of the feeder to sag and the dificulties of maintain-ing uniform temperature and hence viscosity of a compara-tively large body of glass at the stream ~low section o a feeder.
It is an object of the present invention to obviate or mitigate the above disadvantages.
According to the present invention there is proviaed a method of ~orming glass fibers comprising de-_ 2 ~" , .
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~668~5 live.ring discrete streams of molten glas~ through per-forations in a planar surface of a plate, directing a flow of fluid upwardly to impinge against the planar surface at such a veloci-ty and such a volume as to cool the plate to a temperature below that: at which the streams of molten glass will flood over the planar surface thereby to promote the delivery of discrete streams, and attenuating the streams downwardly into fibers.
The invention also provides apparatus for forming glass fibers comprising a container for hold-ing molten glass, said container including a generally horizontally disposed flat bottom wall having perfora-tions for delivery of molten glass from the container as discrete streams, the performation delivery outlets being at the external planar surface of the flat bottom ~ :
wall, means for directing a ~low o~ fluid upwardly for impingement against the perfo~ated external planar sur-face of the flat bottom wall at such a velocity and at such a volume as to cool the bottom wall to a tempera- . .
ture below that at wh.ich the streams of molten glass will flood over the external planar surface area there-by to promote the delivery of discrete streams from the perforations, and means for attenuating the glass streams to fibers.
In one embodiment the stream feeder plate can have a comparatively large number of small orifices or openings in closely spaced relation. Several stream flow units o~ this character may be employed concomi.tant- -ly to provide a group of streams of glass from each of '''~
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89~i the units, the groups of streams being attenuated into filaments and filaments of the several groups combined to form a strand or strands by converging the groups of filaments from the several units into one or more strands, each strand con~aining a substantial number of continuous filaments. Thus a large number of streams of glass is delivered from a small area thereby gxeatly reducing the cost of filament forming apparatus ancl pro viding a compact arrangement ~acilitating thP concomi-tant use of several of the fiber forming units to produce one or more strands of glass filaments economically. ..
The invention will be further understood .
from the following description by way of example of embodiments thereof with reerence to the accompany- -ing drawings, in which:- ...........
Figure 1 is a semischematic view illustrat-ing one arrangement or producing a strand of filaments ~-of glass;
Figure 2 is a sectional view illustrating the form of fiber forming apparatus shown in Figure l;
Figure 3 ls a bottom plan view of the arrange-ment shown in Figure 2;
Figure 4 is a bottom plan view of the stream ~ :
flow member shown in Figures 2 and 3;
Figure 5 is a view similar to Pigure 2 illus, trating a modified arrangement of heating the glass; ~.
: Figure 6 is a view similar to Figure 5 illus~
trating another method of heating the glass;

~ 4 ~6~3~5 Figure 7 is an isometric view illus-trating another form o~ apparatus;
Figure 8 is a lengthwise sectional view of the construction shown in Figure 7;
Figure 9 illustrates a plurality o~ fiber forming units shown in ~igure 2 utilized for forming a multifilament strand having a comparatively large number of ilaments;
Figure 10 is a sectional view illustrating a modified form of stream flow apparatus, and Figure 11 is a sectional view illustrating a further form of stream flow apparatus.
Referring to the drawings in detail and ini-tially to Figure 1, there is illustrated an a~rangement or apparatus for feeding streams of heat-softened glass, the streams being drawn into fine filaments by suitable attenuating means. In the form of apparatus illustrat-~:: ed in Figure 1, the stream feeding construction or unit 10 is supported by a fxame construction 12, the unit : 20 10 embodying means adapted to heat an advancing glass rod 14 to soften the glass to a mobile condition where-by streams 16 of glass are delivered through small ori-~: fices in a feeder plate or member 18.
The glass xod 14 is fed downwardly into the unit 10 at a comparatively low rate by suitable feed :
rolls 20 rotated through conventional transmission gear~
ing contained in a housing 24 and driven by a motor 26.
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: 30 ~

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~66~gs The glass rod 14 is fed at a controlled rate to exert sufficient pressure upon the heat~softened or mobile glass of the rod in the unit 10 for ex-truding streams o~ the glass through orifices in the plate 18. The speed o~ rotation of the feed ::
rolls may be varied and controlled by conventional adjustable variable speed mechanism in the trans~
mission housing 24 or by regulating the speed of the drive motor 26.
As shown in Figure 1, the streams 16 of glass delivered or extruded through the orifices ~ .
18 are attenuated into discrete filaments 30 which are converged by a gathering shoe 32 into a group or strand 34 and the strand wound into a package upon a thin-walled packaging tube mounted on a wind- .
ing mandrel 36 of a winding machine 38, the winding collet being driven in a conventional manner by a motor 40. The size of the filaments 30 may be var~
ied by varying the size of the glass streams or mod-ifying the linear rate at which the streams are atte~
nuated into filaments.
~ It is to be understood that, if desired~
:: the filaments may be engaged with a conventional ~; single pull roll or engaged with nip rolls of con-ventional character rotated at ~ilament attenuat-ing speed and the filaments collected upon a conveyor to form a mat or other form ~or further processing.
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10668~S
Figures 2 and 3 illustrate on a la.rger scale the glass stream feeding apparatus of Figure 1. The apparatus is inclusive of a tube or tubular member 44 of metallic material resistant to high tem~
perature such as an alloy of platinum and rhodium, the tube providing a chamber to contain the glass.
The internal diameter o~ the tube 44 is slightly larger than the diameter o~ the glass rod 14 pro-viding the glass supply whereby the rod is snugly but slidably mo~able in the feeder cha~ber provid-ed by the tube ~4, Welded or otherwise securecl :~
to the lower end of the tube 44 is a circular disc or member 46.
Welded to an upper region of the tube 44 is a similar disc 48, the discs 46 and 48 being of an alloy of platinum and rhodium or other metallic mater-: ial resistant to high temperatures. Also surround the tube 44 adjacent the disc 48 is a circular frame mem- -:
~ ber 50 which is secured to and ~orms a component of the : 20 - ~ ','' . ~
: ;'-:: :
: ';

~ 30 ~ :
: ~ " '~:

~ 7 ;,''';'^,~ , ' 1~6613~i supporting frame structure 12. Depending from the periphery oE
the member 50 is a circular metal member 52 supporting an annular metal member or rin~ 54. Disposed adjacent and below the ring 54 .is a circular disc or element 56 having a counterbore 58. The member 56 is supported f.rom the ring 54 by bolts 57.
Disposed in contiguous contact with the platinum alloy disc 46 is a stream flow member, body or plate 60 having a perfor-ated stream flow area 62 provided by a comparatively large number of openings or orifices 64 in the plate 60, as particularly shown in Figures 3 and 4, the stream flow area being in registration with the interior of the tube 44.
The stream flow pla~e 60 is preferably comparatively thin and is supported by a plurality of discs or washers 6~ of refrac-tory nested in the counterbore 58 in the member 56. Disposed in a circular recess 70 provided in the member 56 is a blower or nozzle : construction comprising a circular member 72 ha~ing a central passage 74 which registers with the circular central openings of the insulating washers 66. ~ .
The member 72 is supported from the member 56 by screws -20 ~73. The circular member 72 is fashioned with a circular recess 76 which, with a surface 78 constituting the bottom of the recess -; 70, forms a circuIar manifold. An innermost circular region of member 56 i5 fashioned with a frusto-conically shaped surface 80.
An inner circular portion 82 of member 72 is fashioned with a reciprocally- shaped frusto-conically shaped surface 84 which, as shown in Figure 2, is spaced slightly from the rusto-conically shaped surface 80 to provide a clrcular orifice, nozzle or slot :~
86 for directing air from the manifold 76 upwardly into contact : with the lower surace of the plate or body 60 to reducle the temperature of or cool the plate 60.

~66~5 The circular manifold 76 is connected by tubes or tubular members 90 and 91 with a blower 94 or supply of air under pressure.
The entrance 96 of the tubes 90 and 91 into lhe manifold 76 are preferably -tangential, as shown in Figure 3, to impart a spiral path of traverse to -the air in the manifold '76 and to the air delivered through the slot or orifice 86 for contact with the plate 60.
The glass of the rod 14 is heated a5 it moves downwardly through the tube 44 whereby the glass adjacent the plate 60 is in a softened mobile condition. In the form shown in Figure 2, the glass of the rod 14 is heated to reduce the same to a mobile or flowable condition by resistance heating, that is, flowing electric eneryy through the tube 44 and the glass within the tube. Welded or otherwise joined to opposed wall regions of the tube 44 are terminals or terminal lugs 100 engaging the tube 44 throughout a substantial portion of its length. Terminal connectors 102 of conventional character are connected with the lugs 100 and with a supply of controlled electric current of high amperage and com-paratively low voltage.
The flow of electric current through the tube 44 and the glass of the rod 14 is effective to progressively increase the temperature of the advancing rod 14 whereby the gla~s approaching the region of the plate 60 is softened and in a mobile condition, the softened glass being of a viscosity facilitating delivery of streams of the glass under pressure through the orifices 64 in the plate 60. In order to minimize heat losses from the glass and the tube 44, the tube is imbedded or embraced wlthin high temperature resistant reractory 106 as shown in Figure 2.
The member 56 is fashioned with a circular passage 108 ~-to accommodate a circulating cooling fluid, such as wat~r. Water 9 - ' ~6689~

flows into the circular passage 108 through an inlet fitting llO
and out of the passage through an outlet fitting 112, there being a baffle 114 in the passage 108 between the inlet and outlet to promote circuitous flow of cooling fluid in one direction through the circular passage 108. The cooling fluid absorbs heat from the member 56 and associated components in order to maintain them at a safe operating temperature.
The method of operation of the arrangement shown in Figures l through 4 i5 effective for extruding or delivering streams of heat-softened glass through the orifices ~4 under con-ditions avoiding flooding of the glass acros~ the lower surface of the feeder plate 60. As an example of the size and close spaclng of the stream flow orifices in the plate 60, discrete streams of glass are delivered through orifices 64 of about ten thousandths of an inch in diameter, the orifices being arranged in rows, as shown in Figure 4, and the center lines of adjacent rows being spaced about ~wenty-five thousandths of an inch apart without encountering flooding when the plate 60 is maintained at a ~emper-ature lower than that of the glass at the stream flow xegion of the plate by air from the blower.
In operation, a rod of ~lass 14 is advanced at a con-trolled rate by the rotating feed rolls 20 into the tube 44 which provides a melting chamber. As the glass rod moves downwardly into the tu~e 44, the glass is progressively increased in temperature by electric current flow through the glass. The glass upon reaohing the region 6~ above and adjacent the plate 60 is softened to a sufficiently low viscosity to facilitat~ flow of streams of glass under pressure through the orifices 64.
In the method of operation of the arrangement shown in Figures l through 4, the speed of rotation of ~he feed rolls 20 is ~
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~iL06G895 con~rolled or regulated so as to exe.rt a downwardly acting pressure on the so~tened glass adjacent the feeder plate 60, the pressure extruding the mol-ten glass at the re~ion 61 through the ori:Eices 64.
A stream of air is concomitantly dlelivered through the circular slot or orifice 86~ the air being p.rojected upwardly into contact with the plate 60 to continuously cool the plate whereby the plate is maintained at a temperature below the temperature of the glass in the region 61.
It is found that for a glass, such as conventional "E"
glass, a temperature differential between the temperature of the softened glass at the region 61 and the temperature of the plate should be between 50~ and 150F,the temperature differential being maintained substantially constant by regulating or controlling the delivery of air from the blower slot 86 by a valve or damper 9S, shown in Figure 3, in the air supply manifold. When these con-ditions obtain it is found that there is no flooding of the glass encountered at the lower surface of the plate 60 and the streams of glass are maintained discrete and separate even thoùgh the . :2Q streams are in very close relati.on.
- . As an example of the operating temperatures in the ~ . .
:utiliza~ion of "E" glass in forming streams for attenuation to : .
filaments, the plate temperature may be between 2050 F and 2100 F

~wlth~the glass at the region 61 of a temperature not less than :~` 2150F.
: ~ The temperature of the plate 6Q may be regulated and controlled by modifying the amoun~ of air delivered in a given ~ .
~: unit of time through the slot 86, the amount of air being con~ ;~
trolled by the valve or damper 95.
~: 30 It is further found that the glass at the region 61 - 11 ~ -'.:

~6~
should be under pressure suficient to effect continuous extrusion of the glass through the perfora-tions or orilice~ 64 as well as to a-ttain the desired throughput of glass per unit of time through the fiber-forming unit. It is further ~ound that the plate ~0, which preferably is an alloy of platinum and rhodium or other metal resistant to -the high temperatures, may be comparatively thin being not less than .002 inches in thickness and preferably of a thickness of .005 of an inch or more dependinq upon the vi cosity of the glass, the pressure exerted on the glass, and the temperature dif-ferential to be maintained between the plate and the molten glass adjacent the plate.
In the use of a comparatively thin ~tream flow plate, the perforated area is comparatively small so as to provide sufficient structural strength to withstand a downward pressure of the glass of about fifteen pounds per square inch without rupture.
The pressure of the glass on the plate 60 may be between three pounds and twenty pounds per square inch. If a plate ~0 of greater thickness is used, the glass pressure may be increasad to secure increased throughput.
Figure 5 illustrates an arrangement similar to Figure 2 but wherein the glass rod is heated by induction. The rod 14' of glass is delivered downwardly at a controlled rate by rotatable ,~, . .
feed rolls 20'. The rod of glass moves through a chamber provided by a tube 44' of an alloy of platinum and rhodium or other high temperature resistant metallic material~
The frame structure supporting the stream 1OW unit includes frame members 12' and a disc 50' engaging a circular member 48' of platinum alloy welded to ths tube 44'. A circular `~-~
m~mber or sleeve 52' depending from the disc 50' supports a rinq ~-54'.

-- - . .^ . - - - ~ , .- , ~66~5 The ring 54' supports a circular membar or disc 56' and an air blower manifold 72'. A perforated stream feeder plate or member 60' is disposed conti~uous Witil the lower surface of a disc 46' of platinum rhodium alloy welded to the lower end of the tube 44'. The central area 64' of the feeder plate 60' is provided with rows of comparatively small perforations as shown in Figure 4, through which streams of glass are deLivered in the same manner as described in connection with the orm ~hown in Figure ~. Wall regions of the manifold chamber76' in the manifold 72' are fashioned with frusto-conically shaped surfaces defining an upwardly slanted circular slot or orifice 86' through which air i8 delivered rom a blower, such as the blower shown at 94 in ~igure 3, into contact with the plate 60' to cool the plate.
The plate 60' is supported by discs or washers 66' of high ~emperature resistant refractory, the washers being supported by the member 56'. The member 5Ç' has a circular passage or chamber 108' through which cooling water or other heat-absorbing fluid is circulated to maintain the disc 56' and associatad com-ponents at a safe operating temperature. The tube 44' is surroun-ded by an inductive heating unit or coil 120 supplied with electriccurrent from a controlled source (not shown) through current con-ductors 121 in a conventional manner.
The induction heater coil 120 is positioned as close as practicable to the tube 44'. The induction hea~ing coil is sur- ;
rounded by high temperature resistant refractory 122.
~;~ The operation of the arrangemen-t shown in Figure 5 is substantially the same as the operation of the form shown in Figure 2. The induction heater 120 progre~sively increases the ; temperature of the gIass of the advancing rod 14' whereby the ~0 lower portion of the glass of the rod is reduced to a soEtened ' ' . ~' ::

8~5 flowable or mobile condition at the recJion 61' above the plate 60', the soft~ned glass ~t the region of transi-tion of the glass to a softened state engaging the wall of the tube 44' provides an effective seal so that cons~ant pressure exerted on the rod 14' by the feed rolls 20' will effect extrusion of the heat-softened or flowable glass at the region 61l through the orifices at the area 64' of the plate 60'.
The air stream deliver~d through the circular slot 86' contacts the plate 60' and maintains the plate 60' at a tempera-ture lower than that of the glass at the region 61'. The glassstreams extruded throu~h the orifices at the perforated region 64' form discrete stxeams and the glass does not flood across the lower surface of the plate 60' during attenuation of ths streams to ~ -filaments. -~
Figure 6 shows an arrangement similar to Figure 5 illus-trating another method and means of heating the advancing glass rod -to reduce the glass to a mobile or flowable condition at the region adjacent the stream feeder plate.
In this form the glass rod 14a is advanced by rotatable .
feed rolls as in the other forms of apparatus to advance the glass rod through a tube 44a fashioned of an alloy of platinum and rhodium or other suitable material. Welded to ~he tube 44a at its ;
upper region i5 a circular disc 48a and at its lower end a similar disc 46a.
Depending from the fr~me component SOa is a circular wall 52a supporting an annular member or ring 54a A circular member 56a is supported from the ring 54a by bolts 57a. The stream feeder plate 60a of the same character as shown in Figures 2 and 5 suppoxted in contiguous engaging relation with the disc 46a by annular members 66a of refractory nested in a recess prov:ided in ~L~66~95 the member 56a. A blower manifold 7~a supported by member 56a is fashioned with a maniEold chamber 76a.
The innermost regions of the blower member J2a and the member 56a are shaped to provide a circular blower orifice or slot 86a through which air from the manifold chamber 76a is pro-jected upwardly into contact with the plate 60a for cooling the plate to a temperature below that of th& glass at the region 61a adjacent the plate 60a. The member 56a is provided with an annular chamber 108a to accommodate a circulating heat-absorbing fluid such as water to maintain the member 56a at a safe oper-ating temperature.
In the form of apparatus illu~trated in Figure 6, an internal combustion burner provides the means for heating the glass of the rod 14a as it moves downwardly to reduce the lower end region of the rod to a softened or mobile state, the softened glass being of a temperature and viscosity whereby streams of the glass may be extruded through the perforated or orificed - ~ area 64a of the plate 60a. The combustion burner is of annul~r shape and surrounds the chamber provided by the tube 44a. The burner is fashioned with a lining preferably of refractory 134 defining an annular combustion chamber 136 A clrcular rear wall 138 of the combustion chamber is -formed with a plurality of small passages 140 to admit combus- -tible mixture of fuel gas and air from an annular manifold 142, ; the perforated wall 138 forming a fire screen to prevent igni-tion of the mixture in the manifold 142. Combus~ible mix~ure is delivered to the mani~old 14~ from a supply through a pipe :
144, a valve means 146 being disposed in the supply pipe for regulating the delivery of mixture to the burner. The mixture ~; 30 is introduced into the combustion chamber 136 under comparatively - 15 - ~ ~
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~6~g~
low pressure of about five pounds per square inch, and the mix-ture ignited and burned in the chamber 136.
The heat of the burning gases in the annular chamber 136 heats the ~lass rod 14a as it is advanced through the tube 44a, the lower end region of the glass rod being reduced to a softened or flowable condition by the heat f:rom ~he chamber 136.
The gases of combustion flow upwardly through an .:
annularly~shaped chamber 137 forming a continuation of the chamber 136, the hot gases in the chamber 137 progressively in-10 creasing the temperature of the advancing glass rod 14a. The ~. -gases from chamber 137 are exhausted from chamber 137 through one or more exhaust pipes 150 ~or discharge at a region remote from the burner. ..
In the arrangement sho~n in Figure 6, the glass rod is progressively heated and becomes softened in the lower region .~ -61a of the chamber provided by the tube 44a to a vis~osity :.
: suitable for delivery under pxessure through the orifices to : ~-provide the streams 16a of glass for attenuation to ~ilaments ; .
30a. Through the continuous delivery of a stre~n or jet of air through the circular orifice 86a from the manifold chamber 76a, the plate 60a is maintained at a temperature below the tempera~
ture of the molten glass in the region 61a above the plate and :~;
wetting or flooding of the lower surface of the plate by the glass lS substantially eliminated ox prevented. The control of the heatlng of the glass is exercised by manipulation of the ; valve 146 regulating the combustible mixture delivered into the .
~: bur~er chamber 136. ~ .
:
Figures 7 and 8 illustrate another arrangement for ~:: carrying ou~ the method of extruding streams of glass through .
~0 closely oriented or spaced orifices in a feede.r plate utilizing - 16 - .~

'. ' .

~66~5 a substantially rect~ngular glass body or plate of glass as a supply, is fed toward the feeder plate and the glass being pro-gressively increa~ed in tempQrature as it i9 fed or advanced toward the stream feeder plate and red~lced to a sotened or mo-bile state at a region above and adjacent the feeder plate.

In this form the chamber recaiving ~nd containing the glass is provided by a tubular member 160 formed of an alloy of platinum and rhodium or other high temperature resistant material, the member being of substantially rectangular cross section.
The interior dimensions of the tubular member 160 are such as to snugly, yet slidably, receive and accommodate a glass supply in the form of a glass plate 164 which may be advanced into the tube 160 by conventional feed rolls (not shown) engage-able with opposed wall surfaces of the glass body and driven at a controlled rate to advance the glass body into the tube at the rate at which the glass is extruded or delivered through orifices in a feeder plate. Surrounding the upper region of the tube 160 is a laterally extending rectangular shaped collar 166 ~ which may be secured to frame members such as frame members 12 shown in Figure 2 for sup~orting the tube 160.

A similar rectangular shaped member 168 is disposed at the lower end of the tube 160 and is preferably welded to the lower end of the tube. A stream feeder plate 170 is con-tiguous with the lower surface of the member 168, the region of the membex 170 in registration with the interior of the tube 160 heing fashioned with rows of small orifices 172 in closely oriented or spaced relation. The orifices 172, for example, may be about ten thousandths of an inch in diameter arranged in rows of a~out twenty-~ive thousandths of an inch between centers of 3~ adjacent orifices in a row, and the rows spaced on center lines :, ..

-~6~:i895 about twenty-f:ive thousandths of an inch apart.
Disposecl beneath the feeder plate 170 are spacers or rectangularly-shaped washers 174 of refrac-tory which are nested in a suitable recess in a rectangularly-shaped member 176 SU5-pended from the frame members by supports or rods 178. A sub~
s-tantially rectangular blower member 180 is disposed in a recess in the\member 176, the blower being of substantially the same general construction as the blower illustrated in Figure 2 but is of rectangular shape~
10The blower member 180 is fashioned with a manifold chamber 182 provided with interior angularly disposed surfaces 184 which with angularly disposed surfaces 186, fashioned on member 176, provides a slot or orifice 188 of substantially rec-tangular configuration to deliver a stream of air onto the plate 170 to cool the plate. The rectangular member 176 is provided with a peripheral passage or chamber 190 preferably of rectan-gular shape by reason of ~he rectangular shape of the member 176. The passage or chamber 190 accommodates circulating cooling fluid to maintain the member 176 at a saEe operating ` 20 temperature.
-In this arrangement the end walls 161 of the rectan-yular tube 160 are provided with terminal lugs 192 and 194 for connection with current supply conductors for supplying elec-tric current to the tube lS0 for heating the body of glass 164 being fed downwardly through the tube 160. The current supply to the ~erminal~ 1~2 and 194 is controlled by conventional ~;~ means to regulate the heating of glass of the body 164 whereby the lower region of the glass 196 adjacen~ the feeder plate 170 is in a softened and mobile condition. The tube 160 m~y be surrounded with refrac~ory (not shown) to minimize heat losses.

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~68gS

In the operation of the arrangement shown in Figures 7 and 8, the pre:~ormed glass plate is advanced by feed rolls (not shown) at a controlled rate and the heating of the glass through the flow of electrical energy through the tube 160 and the glass progressively increases the temperature of the glass during its downward movement so that as it approaches the plate 170, the glass is in a softened or mobile condition.

The feed rolls exert pressure on the glass body 164 whereby pressure is exerted on the sofkened glass at the region 196 adjacent the plate 170 whereby streams of glass are extruded through the orifices 172 in the feeder plate 170. As the :~
stream of air delivered through the orifice 188 continuously contacts the plate and maintains the plate at a reduced temper- :
ature, the glass does not flood across the surface of the plate ::.
and the streams remain discrete even though they are in closely oriented relation.

The streams may be attenuated to filaments 200 by winding the filaments in a strand form upon a rotat.ing col- -lector of the character shown in Figure 1, or attenuated by other means, such as a pull roll or nip rolls, in a we~l known conventional manner. Through the arrangement shown in Figures 7 and 8, a comparatively large glass stream flow area is pro-vided in the plate 170 and as the perforated area of the plate .~
is comparatively narrow, being about the width or thickness of ~::
the glass plate or body 164, the plate will withstand th~ feed pressure exerted on the glass plate without fracturing. The . :

throughput of glass is substantially increased through l:he use ., ,.:;
of a plate or xectangular body of glass as the glass supply.

'~:

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Figure ~ illustrates the use of a plurality of fiber-forming unlts lOb of the character illustrated in Figures 2 and 3 providing for the concomitant attenuation of a plurality of groups of streams of glass extruded rom a plurality of fiber-forming units. Each unit lOb is supplied with a gla~s rod or body 14b delivered by pairs of feed rolls 20b fed into the chambers provided by the tubular members 44b, the glass bleing heated by electric energy delivered through current supply con-ductors connected with the texminal lugs lOOb, the blower mani-fold members 72b may be supplied with air from a blower through an air manifold pipe 210 connected with an air blower of thP
character shown at 94 in Figure 3, or other supply of air under pressure.

Air from the supply pipe 210 is delivered to each blower through branch pipes 212. The air delivered to each blower may be regulated or controlled by valve means 214 asso-ciated with each of the branch pipes 212. Each unit lOb is - provided with a feeder plate 60b of the character shown at 60 in Figure 2 for delivering a group of glass streams in closely spaced relation from the feeder plate o each unit. The streams are attenuated to filaments 30.

The groups 216 and 218 of ~ilamen~s may be converged . :
by a gathering shoe 220 to form a strand 222 comprising the filaments of the several groups, the strand 222 being collected upon a winding collet in the conventional manner. If desired, ;the individual groups may provide individual strands which may be concomitantly wound upon dual collectors or tubes of a : winding machine to form two independent packages.

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~L0~;~895 Figure 10 illustrates another form of apparatus for perfcrming or carrying out the method of the invention. In this arrangement the glass supply is maintaimed in a heat-softened condition at a temperature and viscosi-ty wherein the glass may be readily extruded through one or more groups of orifices in a plate which is maintained at a tempera~ure less than that of the heat-softened glass adjacent the plate. A
walled receptacle 230 for containing the glass, in the embodi-ment illustrated, is of substantially rectangular shape but may be of circular or oval configuration if desired.

The receptacle 230 is provided with a floor or bottom section 234 and with a cover or closure 238 to facilitate pres-surizing the receptacle. The end walls 240 of the receptacle are provided with terminal lugs 242 for connection with current conductor terminals 244 supplying electric current ~o the xe~
ceptacle and the glass therein for melting or heat-softening the glass and maintaining the so~tened glass at a proper vis-cosity for forming the glass streams.

In the embodiment illustrated, the cover 238 is pro-vided with a tubular fittlng 246 equipped with means for -~
metering or controlling the delivery of pieces of glass, such ;~ -as glass marbles, into the receptacle 230. The gating or metering means is of conventional character and comprises a :~ .
rotatable shat ~48 eguipped with gates or vanes 250 contained ~- within a cylindrically shaped housing member 252, the gates or vanes 250 snugly fitting against the inner wall of the housing 25~ to provide a seal. The pieces or marbles of glass :
, ~L~6~ 135 are ed to the metexin~ mcans from a supply (not shown) through a tube 254 in a w~ll known con~entional manner.

~ lso connected with the cover 238 or with the recep-tacle at a region above the level o glass in the receptacle is a pipe 258 connected with a supply o~ air or other gas under pressure for maintaining pressure above atmospheric pressure in the receptacle 230 for extruding the glas~ through orifices in a feeder plate. The pressure may b~ controlled by a valve 259 associated with the pipe 258. Positioned contiguous and in con-tact with a lower surface 260~of ~he receptacle floor 234 is a stre~m feeder plate 264. The floor 234 is fashiDned with spaced passages 266 through which glass is delivered to perforated or orificed regions of the plate 264.

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Disposed in registra ion with each of the passages 266 are perforated regions 268 of the plate 264, each region com-prising a comparatively large number of small orifices 270 through which the glass is extruded from the feeder chamber 236.
.
Positioned beneath the stream feeder plate 264 is a series of stacked members 274 of refractory which are supported by a mem- `
ber 276. The member 276 is provided with a chamber 278 accom-modating cooling fluid to main~ain this member at a safe oper-ating temperature. The member 276 is provided with a recess 279 accommodating a blower construction 280.

The blower comprises a member 282 fashioned with a series~of circular manifold chambers 284, the member 276 and the .
.

~66~3~5 blower member 280 having pairs of coopera-ting frusto~conically shaped surfaces providing circular orifices 286 bounding pas-sages 288 in -the blower member 2821 a passage 288 being in registration with each of the passages 266 of the floor 234 of the recep-tacle 230.
The manifold chambers 284 are connected with a supply of air under pressure such as the blower 94 shown in Figure 3 or other compressed air supply. Air streams are delivered through the circular orifices or slots 286 into contact with the lower surface areas of the plate 264 at the perforated regions 268 to . ~
10 reduce the temperature of or cool the plate 264. ~ .
Glass marbles are fed at a controlled rate through the marble gating or metering means 250 and the glass reduced to a ~. .
softened or mobile condition by electric current flowing through ~ -the receptacle 230 and the glass therein. Air or other gas at a constant pressure is admitted through the tube 258 thereby ~
pressuring theglass under sufficient pressure to extrude streams ~f the glass simultaneously through the orifices 270 at the perforated regions 268 in the plate 264. :~
The streams of glass delivexed from each of the perforated areas 268 may be attenuated to fine filaments and the : groups of filaments from the several areas converged in~o a 1 ~
strand and the strand wound into a package in the manner descri~ . -.:
bed in connection with Figure 1, or the groups of filaments derived from attenuation of the groups of streams may be converged to form two or more strands. Through the arrangement illustrated in Figure 10, a substantial throughput of glass is -attained through the use of several groups of stream feeder orifices thereby rendering the process economical. The use o~
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: - 23 -106689 ~ii the stream feeder plate ma:intained at a temperature below that of the glass avoids 1Ooding of the glass at the lower surace areas of the plate at the stream ~eeder regions.
Figure 11 illustrates another form of apparatus, the apparatus embodying a mech?anical means for pressurizing the heat-softened glass for extruding the glass through open-ings in a stream feeder plateO The arrangement includes a walled receptacle 300 providing a melting chamber 302, the receptacle being fashioned of an alloy of platinum and rho- :~
dium or other high temperature resistant metallic material, The receptacle 300 is provided with a cover 304 equippPd .
with tubes 306 through which bodies or marbles of glass are introduced or fed into the chamber 302. ::~ -Each of the tubes 306 is connected with metering means such as that show?n in Figure 10 for regulating and con-trolling the delivery of bodies or marbles 308 of glass into ~ .
: the chamber 302. In the arrangement shown in Figure ll,the receptacle 300 is heated by electric current for reducing the glass to a molten or mobile condition. Secured to opposite . . .
wall regions o~ the receptacle 300 are terminals or lugs 310 -~
engaged by current supply conductors 312 connected with a source of electric energy for heating the receptacle ~? the elec-tric current being regulated by well known conventional means : (not shown). A perforated, current conducting heater strip 314 extends across the chamber 302 below the level oE the glass : to promote heating of the glass.
The receptacle 300 is fashioned with a tube or tubu-: lar extension 316 o~ circular cross section, the tube being of platinum and rhodium alloy and joined to the floor of the receptacle.
.

: ~ 24.~

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- , 1~6~
In this form the floor or Eloor portion 324 of the receptacle is the stream feeder plate or member and may be an integral portion of the tube 316, the latter providing a cylin-drically-shaped chamber 322 containing heat-softened glass.
The floor or stre~m feeder plate 324 is provided with a group of small orifices 326 similar to the group of orifices in the plate 60 shown in Figures 2 and 4.
The floor or feeder plate 324 is engaged by annular members 328 of refractory, the members 328 being supported in a recess in a member 330 of the same character as the member 56, shown in Figure 2. A blower construction 332 of the character shown in Figure 2 is supported by a member 330 for delivering a stream or jet of air through a circular orifice 334 into con-tact with the lower surface 336 of the stream feeder plate 324 to cool the plate. The member 330 is supported by suitable frame means (not shown).
The receptacle 300 and the tubular extension 316 are surrounded with refractory 350 to minimize heat losses. The cover 304 is fashioned with an opening accommodating a tubular itting 352 through which extends a rotatable shaft 354. The end region of the shaft extends into the chamber 322 provided by the tube 316 and is equipped with an impeller 356 of conventional -construction, the tips of the impeller blades or vanes being disposed close to the wall of the tube 316 but being rotatable therein in a direction to exert downward pressure on the softened glass in the chamber 322.
The shaft 354 and impeller are driven by an electri-cally energized motor (not shownl of conventional character.
The speed or rotation of the shaft 354 may be varied and con-trolled by conventional speed reducing mechanism associated with _ 25 _ -68~5 the drive motor or by regulating the speed of the mo-tor. Through this arrangement the rotation of the impeller 356 exerts a con-stant pressure on the softened glass in the chamber 3~2 whereby the glass is extruded in streams through the small orifices 326 in the stream feeder plate 324. The downwardly directed pres-sure on the glass established by rotation of the impeller 356 may be varied and controlled by regulating the speed of ro-tation of the impeller. :
In the operation of the arrangement shown in Figure 11, pieces or marbles of glass or glass batch are fed throughthe tubes 306 into the chamber 302 at a controlled rate equal to the throughput of glass through the orifices 326. Air under pressure is supplied to the manifold of the blower 332 and a jet or stream of air delivered into contact with the stream feeder plate 324 to reduce the temperature of the plate to between 50F and 150F below the temperature of the softened glass adjacent the feeder plate in the chamber 322.
Electric energy is supplied to the receptacle 300 and heater strip 314 ~o reduce the pieces, marbles or glass batch to a softened or viscous molten condition, the rate of melting or softening of the glass heing controlled by regulating elec-tric current flow to the chamber 300.
The pressurizing impeller 356 is rotated at a speed to develop a downwardly acting constant pressure on the glass in the region 322 whereby the glass is extruded -through the orifices 3?6 in fine streams which are attenuated to filaments in~the manner illustrated in Figure 1.
The reduction in temperature or cooling of the plate 324 enables continuous delivery of s~reams of glass through the ~6~ 5 orl~ices 326 without Elooding of the glass over the surface ofthe plate 32~ whe.reby the ylass s-treams are maintained in dis-crete form for attenua-tion -to continuous ~ilaments.
Processing o~ the glass is perEormed or carried out through the establishment and coordination of particular operat-ing characteristics and conditions whereby streams of glass may be successfully extruded through closely spaced orifices or open-ings in a metal body or plates wherein the plate is maintained at a temperature below that of the glass adjacent the stream ~
10 flow region of the plate and the glass pressurized whereby ~.
discrete streams are formed which may be attenuated to filaments and without flooding the obverse surface of the stream feeder body or plate. ~-While the reasons for and principles involved in attaining a nonwetting condition may not be fully understood, there are numerous factors or relationships that have been found ~ :
to be instrumental in promoting flow of streams of glass without . .
encountering wetting of the stream flow area of a feeder plate during operation and the maintenance of the streams in independ-20 ent or discrete form so as to facilitate their attenuation to ` ``
filaments. It has been found that several factors or conditions have a bearing upon attaining a nonwetting environmen~.
: One of the factors involves the continuous dissipation of heat energy from the stream delivery region or section of the stream feeder plate to establish a substantial temperature dif-ferential between the softened ylass adjacent the pla~e and the stream delivery surface of the plate~ As previously mentioned herein~ the temperature of the feeder plate should be between 50F. and about 150F. lower than the glass temperature.

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~L~96~8~5 Another factor bearing upon the success of the method is the maintenance of a proper temperature and hence viscosity of -the softened ~lass at the stream flow section of the plate.
It has been found by test that the viscosity of the glass should be such that the glass is in a mobile state but of a viscosity high enough that streams of the glass will not readily flow through the orifices under the influence of gravity but requires comparatively low pressure to extrude the softened glass through the orifices to provide the glass streams. It is found that a pressure on the ~oftened glass is required IlOt only to extrude the glass through the orifices but is one of the factors in promoting the nonwetting characteristic.
It has been found by tests that different degrees of tendency toward nonwetting are in a measure dependent on vari-ations in pressure on the glass. PressurPs between five pounds per s~uare inch and twenty pounds per square inch in association with other factoxs will result in continuous stream delivery with virtually no tendency toward wetting of the feeder plate surface or interadhesion between adjacent streams even though ~-they are~in close relation.~ The reduced temperature of the plate results in the plate having~a higher contact angle with glass ànd this factor tends to reduce "wet out".
There are several energies or Pnergy factors believed to be involved in the attainment of satisfactory nonwetting characteristics. Among these energies are the in-terface energy ~etween the metal of the stream feeder plate and the glass, interface energy between the metal and the air stream directed onto the plate for cooling the plate, and the interface energy between the ~ir and the glass at the stream delivery region.
It is believed that a proper balance of these energies or forces : ~ ' ' 8g5 results in a stable condition fostering a nonwetting or non-flooding tendency. An imbalance o the energies promote~ dif-ferent degrees of wetting of the feeder plate fostering differ-ent d~grees in the tendency for flooding to occur.
Another actor that is believed to bear upon tha operation of the method is the "wet out" time or rate, this being the time factor within which the molten glass is enabled to move or migrate onto or in contact with a~ adjacent surface.
It has been found that where the softened glass is a~ a com-paratively low temperature but of a viscosity at which it willmigrate or flow, that the "wet out" time or rate, that is its rate of migration or movement is decreased and hence its faculty ;
for flooding is likewise diminished.
Another factor bearing upon the "wet out" rate or time is the pressure on the glass tending to extrude or force the glass through the orifices in the fee~er plate. It is found that if the pressure on the glass is increased, the vel-ocity of the glass extruded through the orifices is increased, thus reducing the "wet out" rate and thereby promoting a non-flooding condition. Furthermore, the high discharge velocitiesof the glass through the small size orifices provide a substan-tial increase in throughput for the desired fi~er diameter as ; compared with the throughput of conventional larger orifices at reduced glass velocity.
From the results of tests in the use of stream feeder plates of varying thicknesses, it is found that satisactory nonwettin~ or nonflooding condition is attained with a ~esser amount of pressure on the glass when a comparatively thin feeder plate is employed. For example, if the stream Eeeder pl~te is increased in thickness, then the pressure should be increased : ' - 29 ~

~ ' ~6~89~i;
in order to attain the same velocity of flow of the glass through the oriices in order to provide the same "wet out" rate attainecl through the use of a thinner plate and less glass feed pressure.
In operation, it is found that where heat energy is being removed or transferred from the stream feeder plate at a substantially constant rate as by directing an air stream into contact with the plate as hereinbefore described, the extruded streams remain individual and discrete and may be successfully attenuated into filaments. It is found that when heat is not removed or transferred from the plate at a constant rate as, for example, when the air stream is interrupted, the glass readily floods the orificed area of the feeder plate resulting in the streams becoming joined into a single body.
However, when delivery of the air stream is restored and ths glass body manually pulled downwardly, the glass immedl-ately separates into discrete or independent streams and no further tendency toward flooding is encountered so long as the feeder plate is maintained at a reduced temperature and the other operating conditions such as the proper temperature and the ; 2~ viscosity of the glass and the proper pressure maintained on the glass ~to extrude the streams through the orifices. The rate of ; ~extrusi~on of the glass through the orifices must be constant and coordinated with the linear rate of attenuation of the streams to filaments in order to secure filaments of uniform size.

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Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of forming glass fibers comprising delivering discrete streams of molten glass through perforations in a planar surface of a plate, directing a flow of fluid upwardly to impinge against the planar surface at such a velo-city and such a volume as to cool the plate to a temperature below that at which the streams of molten glass will flood over the planar surface thereby to promote the delivery of dis-crete streams, and attenuating the streams downwardly into fibers.

2. A method according to claim 1 wherein the step of delivering the discrete streams of molten glass through the perforations comprises heating the glass to a temperature at which it flows through the perforations to form the discrete streams.

3. A method according to claim 1 wherein said fluid is air.

4. A method according to claim 1, 2, or 3 wherein the discrete streams are delivered from the perforations in such closely-spaced relation as to flood over the planar surface in the absence of the flow of fluid.

5. A method according to claim 1, 2, or 3 wherein said plate is a generally horizontally disposed thin metallic plate.

6. Apparatus for forming glass fibers comprising a container for holding molten glass, said container including a generally horizontally disposed flat bottom wall having per-forations for delivery of molten glass from the container as discrete streams, the perforation delivery outlets being at the external planar surface of the flat bottom wall, means for directing a flow of fluid upwardly for impingement against the perforated external planar surface of the flat bottom wall at such a velocity and at such a volume as to cool the bottom wall to a temperature below that at which the streams of molten glass will flood over the external planar surface area thereby to promote the delivery of discrete streams from the perforations, and means for attenuating the glass streams to fibers.

7. Apparatus according to claim 6 wherein the perfor-ation delivery outlets are spaced close enough together to be in flooding relationship in the absence of the flow of fluid.

8. Apparatus according to claim 7 wherein the perfor-ation outlets have a diameter of about ten thousandths of an inch and are located with their centers spaced apart about twenty-five thousandths of an inch.

9. Apparatus according to claim 6, 7, or 8 wherein the bottom wall has a thickness of between two and five thousandths of an inch.