US 2571025 A
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Description (OCR text may contain errors)
Oct. 9, 1951 E. FLETCHER 2,571,025
APPARATUS FOR PRODUCING FIBERS Filed Dec. 30, 1948 2 Sheets-Sheet l INVENTOR. Ed EZe/Zchcr 'ATTOR/VEYS Oct. 9, 1951 FLETCHER APPARATUS FOR PRODUCING FIBERS 2 Sheets-Sheet 2 Filed DeC. 30, 1948 INVENTOR. Ed EZeZCh/er BY W M Patented Oct. 9, 1951 2,571,025 APPARATUS FOR PRODUCING- FIBERS Ed Fletcher, Newark, Ohio, assignor to Owensof Delaware Corning Fiberglas CorpOration a corporation Application December 30, 1948, Serial No. 68,162
invention relates to apparatus "for prodfiCl-Fig fibers fromgl'ass'cr materials having characteristics sin'iilar' to g lass.
one highly satisfactory process for com- IfilclSlllY manufacturing'fine"fibers from glass or materials which maybe drawn-"out when in a softened or molten condition is to flow a multiplicit'y of individual streams of the material in a'downward direction from a "suitable feeder or bushing containing a body ofthemolten or'heat softened material. As the stre'ams pass from the feeder; the material is solidified sufiiciently to enable engaging. the same by power driven feed rolls, and'thes'e rolls impart suflicient force to the material in the direction of fiow of the str'eamsto attenuate the streams into rods or filaments. Thefi-laments'are' also advanced by the feed rolls into a wide relatively thinblas't' of gas having a temperature exceeding the softening temperature of 'thernateria'l', and having a velocity sufiicient to attenuate'the heat softened Inater ial into fine fibers'. It i's-also'commonprac the to guidethelprimary filaments endwise into the blast by'aguide designed to" spacethefilaments laterally withrespectto one another ina row extendingacross the width of the blast.
The general aim 'is to feed as many primary filaments intothe'bla'st as possible without disrupting the-flow of the blast, so that the maxim'umproduction of fiberscan be obtained from a single burner. However, there-are practical reasonswhy it is desired to'provideas much space aspossible between the adjacent streams flowing from the feeder to the guide. In this connection there is a tendencyfor the streams-to vibrate or shift laterally with respect to one another as they are dischargedintothe atmosphere from the feeder, and there is the danger that one or more of the streams will contact adjacent streams; This would result-in the streams adhering to each" other, and would cause a disruptiondnthe operationo'f the equipment. In-addition the primary "filaments'are usually'manually threaded into the guide following "breakage or disruption-of the-process for-any reason, and ample spacing between the adjacent filaments must be providedto" facilitate handling of the filaments.
Withthe above in=view,:it is'one of the objects of this invention to provide apparatus rendering fit-possible to feed a greater number of primary filaments into a blastof given width, andat the same time; providewample spacing. between the windividual?glass streamsflowing from the-feeder .tothe guide. Thus the production of fine glass 2 fibers with aburner of given size is substantially increased without the necessity of grouping the individual's'treams in such close proximity that disruptive operation may result.
It is another object of this invention to main" tain a sufiicient tension on the streams flowing" from theburner to the guide to minimize any tendency for adjacent streams to contact one another and thereby disrupt the fiber forming operation.
It is a further object of this" invention to provide aguide for the individual filaments having means rendering it possible to facilitate threading the individual filaments into the guide;
A stillfurther object of this invention is' to provide a guide which, in addition'to directing the primary filamentsendwise into the blast-of gas issuing from the burner or other source'of supply, also serves to 'hea'tthe filaments prior'to feeding thesame into required to heat primary filaments of given diameter to the attenuating temperature is materially reduced and the depth or thicknessof the blast may also be reduced. Ifhis is important especially where the temperature and velocity of the blast are determined toa great extent by the size of the outlet opening in the burner cornbustion chamber. In this-connection it will be understod that the velocity or extent'of' reduction of the area of the burner outlet is limited by the temperature required in the blast, so matey reducing this temperature it is possible toproportionately increase the velocity of the blast or reduce the width of the outlet opening. n
The foregoing as well as other objects will be made more apparent as-this description proceeds} especially when considered in connection with the accompanying drawings, in which:
Figure '1 is a semi-diagrammatic sectional view showing apparatus embodying the features of this invention; 7
Figure 2 is an elevational view ofthe'appara'tus shown in Figure '1;
Figure 3 is a plan view of the guide shownin Figure 1;
Figure 4 is a sectional view on the line44 of Figure 3;
Figure 5 is aplanview of the bottom guide section shown'in-Figure 1'; V
Figure 6 is a sectional view taken on the line -fi- -6 of Figure5 and Figure '7 is a fragmentary eievational view of a "modifiedformof guide.
The apparatus forming the subject matter of this invention may be successfully employedin taken substantially the blast. Thus thetiine the manufacture of fine fibers from many different types of materials which are reduced to a molten or softened state .when subjected to heat, and are capable of being drawn out to form fibers when in a molten or softened condition. However, the apparatus is particularly adapted for use in the manufacture of glass fibers, and accordingly, is described below for this purpose.
With the above in view, reference is made to Figure 1 of the drawings, wherein the numeral l designates a feeder in the form of a bushing adapted to contain a body of molten glass, and having a plurality of restricted openings or orifices I l in the bottom wall through which molten glass flows into the atmosphere in the form of streams I 2. This general type of bushing or feeder has been extensively used in the past in'the manufacture of fine fibers from heat softenable material, such as glass, and therefore, need not be described in detail. It will suffice to point out that the bushing is preferably heated in a manner not shown herein to maintain the molten glass therein at such a viscosity that the glass flows relatively freely through the orifices H. These orifices are spaced laterally from each other in a row in order to position the individual streams l2 ,in-a common substantially vertical plane. As the individual streams [2 of glass are admitted to the atmosphere, they are cooled to the point of solidification after being drawn out to form primary filaments [3 by suitable feeding means designated generally by the numeral M. The feeding means I4 also acts to project the primary filaments l3 into one side of an intensely hot high velocity blast B of gas. the blast B extending for an appreciable distance from the point of entry of the filaments into the blast is at a temperature which exceeds the softening point of the glass and moves at a velocity sufficiently high to attenuate the softened glass to form fibers. As will be more fully hereinafter described, the blast B is of substantial width, and the primary filaments H) are introduced into one side of the blast along paths of travel which extend substantially normal to the direction of movement of the blast B.
In the present instance a guide I5 is interposed between the feeding means l4 and the blast B for guiding the individual primary filaments l3 into the blast. The guide I5 is designed to arrange the primary filaments in lateral spaced relation to each other in a row extending across the width of the blast, and the general aim is to feed as many primary filaments 13 into the blast as is possible without disrupting the flow of the gases forming the blast. The problem of feeding a large number of primary filaments l3 into a blast B of given width is aggravated by the necessity of maintaining sufficient distance between adjacent streams I 2 issuing from the feeder H] to prevent contact of the streams as they are projected into vthe atmosphere. In this connection it will be understood that as the streams of glass pass into the atmosphere, they are subjected to the action 'of'air currents and other forces which have a tendency to move adjacent streams into contact, and disrupt the operation of the equipment. In addition it is customary to' manually feed or thread the filaments intothe upper end of the guide 15 following an interruption of the process, and adjacent filaments must be spaced laterally from each other a sufficient distance to enable handling of the filaments during the threading operation. Owing to the above conditions full advantage has not been taken in the past of the attenuating capacity of the blast B, and as a The portion of 4 consequence, production of fibers from apparatus of a given size has been somewhat curtailed.
The apparatus forming the subject matter of this invention renders it possible to feed the maximum number of primary filaments into a blast B of given width without clisrupting'the blast, and at the same time, provides the desired lateral spacing between the adjacent streams l2 issuing from the feeder H]. In general the above result is obtained by designing the guide l5 so that the primary filaments at the entrant end of the guide are spaced laterally from each other throughout a distance which substantially exceeds the width of the blast B, and converge to such an extent as they pass along the guide as to occupy a space at the delivery end of the guide which approximates in length the width of the blast B.
In detail the guide l5 comprises two sections I 6 and. I! supported in vertical alignment by a bracket R8. The bracket l8 also forms a support for the feeding means, which in the present instance, comprises a pair of rolls l9 and 2B rotatably supported at opposite sides of the path of travel of the primary filaments 13. The feed rolls are respectively secured to shafts 2|, and one or both of the latter may be driven by suitable power means. The power means is not shown herein, but is such that the rolls are rotated in the direction of the arrows indicated on Figure 1 of the drawings. The peripheral surfaces of the rolls are preferably formed of a resilient material, such for example, as a rubber composition, and the rolls are supported in positions such that the peripheral surfaces have a rolling contact with opposite sides of the filaments l3 as the latter pass between the two sections of the uide l5.
The guide section [6 is located between the feed rolls and the bushing it]. This section com prises two plates 22 secured in side by side relationship and formed with a plurality of laterally spaced vertical recesses 23 in the adjacent surfaces thereof. The recesses 23 in one plate co-' operate with the corresponding recesses in the other plate to form vertical grooves 24. The grooves 24 are of suflicient dimension to respectively freely receive the primary filaments l3 and are spaced laterally from each other throughout a distance 25 which substantially exceeds the width of the blast B. The lateral spacing between adjacent grooves corresponds to the desired lateral spacing between adjacent glass streams at the bushing Ill, and the distance 25 may be as great or greater than twice the width of the blast B. In any case this distance is suflicient to enable spacing adjacent streams from each other to the extent required for convenient handling of the filaments during threading of the latter into the grooves 24. In order to facilitate threading the filaments 13 into the grooves 24, the latter are preferably flared outwardly at the upper ends in the manner indicated by the numeral 26 in Figure 4 of the drawings. This is an important feature as it reduces considerably the time required for threading the individual filaments into the upper end of the guide.
The section ll of the guide I5 is located between the feed rolls and the blast B. This section also comprises a pair of plates 26 secured to the bracket l8 in face to face relationship. The inner surface of each plate 26' is formed with a plurality of laterally spaced vertically extending recesses 21, and these recesses cooperate'to form gwoves 28. The grooves 28 correspondin-number to thenumbe-rof grooves-24in theguiele. section. t6... and are respectively aligned with the grooves; 24- inorder to. receive the primary filaments lit-from the. guide. section Iii.
-'lE-he grooves; in both guide sections are: sub.- stantially greater in diameter than the diameter. of the primary filaments so that the latter may shift laterally withinthe grooves and this. is important because it reduces. friction which is. one. of the factors responsible for breaking-of the filaments passing from. the. bushing, to to the feed rolls. I-t-is also. pointedout-at thistime that. provision. of grooves of: substantial. diameter. makes it. unnecessary to employ precision. methads for aligning the twoguide sections. It is alsopointed out that. since; the. primary filaments. t3 entering the blast are, advanced in. the direction movement of the-blast, thev adjacent plate 25. ct. thebottom guidesection is. subjected toconsiderable, wear, and accordingly, may be: hardenedor. formed of. a highwear resisting material, if desired.
It-f'ollows from the foregoing that the receiving:. endsof the. grooves. 2.1 are spaced laterally from each other throughout a distance identical to'the distance-zepreviously described in. connection with the: section Iii-of v the guide; The grooves. 21, however, converge toward the bottom of-the-guidesection ll', andare spaced fromeach other atthe bottom of the guidesectionthrough out-a distance. 28- which approximates the width ofthe blast B. Actually the, distance 23 is somewhat less than the width. of the blast Bin order to assure positioningthe end filaments. within the blast. Thus it willbe apparent that full advantage of the blastB. is taken without interfering with. thedesired lateral spacing between the. streams of glass. issuing from the bushingv it.. This is important as. it enables substantially in creasing the quantity of fibers. producedfrom a blast. of given width... and. results in. a. reduction in. cost of. manufacture. of fibers.
In view of the fact that the lower 'end of the guide is. located inclose proximity to the blast B, it' may be desirable tocool' the lower portion of the guide. Hi. This may be accomplished. by circul'ating a coolant such as water through a jacket 30 formed in a part 31 which is secured to one of the plates 26' by suitable. fastener elements 3.2.. Reference has been made above to the fact that contact of adjacent streams E2 of glass disrupts the operation of the apparatus and requires manually restarting the same. In order to minimize accidental disruption of the process, provision is made herein for applying a slight tension to the streams l2. Referring again to Figure 1 of the drawings, it will be noted that apair of rolls 33 and 3d are supported in vertical spaced relationship between the guide 65 and the bushing Hi. The bottom roll 33 is suit-. ably rotatably supported on a bracket 35 which is removably clamped tothe top guide section we adjacent opposite sides thereof by suitable screws 36-. The roll 33 is supported on the bracket 35 in a position to engage one side of the primary filaments and guide the same into the upper end of the guidesection it. The top roller 34 is mounted on a bracket 3'! in a position to engage the opposite side of the primary filaments l3 ata point substantially above'the roller 3-3; It will alsobe noted that the roller 34 is offset. laterally with respect to the roller 33 to cooperate with the latter in applying a slight tensionw the primary filaments. This" tension is suflicienttto'. counteract. any tendency for thefilamerits or'streams. to contact as the latter pass. from'the bushing [0 to the guide I5.
The bracket 31' is adjustably supported on the upperend of a rod 38 having. the lower end adjustablysecured. to a. support 39 by a bracket 39'. The adjustable connection between the bottom of the rod. 38 and the: support 39 is such as to permit varying the oifset relationship between.
the tension rolls and thereby adjust the tension applied by the latter on the primary filaments. This tension. may also be varied by adjustingv the position of; the bracket 31 on the upper end of. the rod 38; if desired.
The blastB is. produced by a-burner 40 having a combustion chamber: 4! formed in'a block kind, but for reasons. ofv economy, it is prefer-- ably'an ordinary fuel gas, such as natural or manufactured gas. This gas is mixed with the proper: amount of. air by means of the orthodox air and gas mixers not shown. herein. The gas and air mixture is taken from the mixer. at moderate pressure of approximately 1 to 5 p. S. i., but may be considerably higher if. desired.
The combustible mixture of gases introduced. into the chamber flows through the perforatedwall G5 into the combustion chamber 4|, and is ignited. Within the. latter. As the gases burn. within the chamber 4! the walls of the latter become extremely hot, and the rate of burning'of the gases is exhilarated to provide a very high rate. of expansion of the products of combustion within the chamber 4|. The burned gasesv or products. of combustion are discharged from the chamber 411 through an outlet open-- ing is formed inthe front wall of the burner and having a length substantially greater than the Width, thereof. The size of. the outlet opening is so proportioned with respect to the volume of the: combustion chamber 4! or the amount of fuel. mixture. burned Within this chamber that the products. of combustion are discharged from the; outlet opening 48 at a temperature in excess of the softening temperature of the glass and at. a velocity sufiiciently high to draw out or attenuate the softened glass to form fibers. The effective area of the. outlet opening may be so proportioned with respect to the volume of the combustion chamber 4! to enable obtaining ablast of gas having a temperature as high or higher than 3000 F. and having a velocity as high or higher than 1200 feet per second. It will, of course, be understood that the crosssecticnal area of the outlet opening 48 may be varied to some extent relative to the volume of the combustion chamber, depending upon the heat. required in the blast B. Outlet openings of greater area relative: to the volume of the combustion chamber M enable burning a greater amount of" fuel mixture and result in generating higher heat in the blast, but also cause a decrease inthe velocity of the blast. It is generally preferred ta form the outlet openingof a; size no greater than necessary to obtain in the l il'ast the heat re'quired toraisetn'e glass to the desired attenuating" temperature.
A combustible mixture of Owing to the shape of the outletopening 48, a blast B is obtained which has a much greater width than depth. However, the depth of the blast is sufficient to assure softening the ends of the primary filaments within the blast to the attenuating temperature before the primary filaments are projected entirely through the blast. The velocity and temperature of the blast is greater immediately adjacent the outlet opening 48. Therefore, it is desirable to locate the burner in such a position with respect to the lower end of the guide I that the primary filaments are fed into the blast immediately adjacent the outlet opening 48. As the ends of the primary filaments i3 are projected into the blast B, the glass is heated to the attenuating temperature by the heat of the blast, and is drawn out to form fine fibers by the force of the blast. The size of the fibers produced depends to a great extent on the velocity of the blast, size of the primary filaments, and the heat of the blast. With a blast B having the characteristics noted above, it is possible to form fibers as fine as one micron or less in diameter from filaments of substantial size. However, regardless of the size of the fibers produced, and regardless of the diameter of the primary filaments employed, the guide 15 previously described enables feeding a greater number of primary filaments into a blast of given width so that maximum production is obtained with equipment of a given size.
The embodiment of the invention shown in Figure 7 of the drawings differs from the above construction in that the cooling jacket 39 is located adjacent the top of the bottom guide section ll, and the plates 26 of the bottom guide section I! are formed of a high heat resistant material, such for example, as platinum or chrome metal alloys. In use the lower end portion of the guide section I! is heated by the blast B of gas issuing from the burner, and this heat is transmitted to the primary filaments I3 passing through the grooves 28 in the bottom guide section. Thus the primary filaments 13 are heated prior to being introduced into the blast B, and this has the effect of producing finer fibers on a greater production basis. With the above arrangement, the time required for the blast to soften or heat the primary filaments to the desired attenuating temperature is substantially reduced, and accordingly, the depth or thickness of the blast need not be as great. Consequently, the width of the burner outlet slot may be proportionately reduced to increase the velocity of the blast and provide a correspondingly greater force for attenuating the heat softened glass into fibers. The purpose of the cooling jacket 30 in the modified form of guide construction is to more or less limit heating of the primary filaments to the lower portion of the guide, and thereby avoid interference with proper feeding of the primary filaments through the guide by the feed rolls.
1. Apparatus for making glass fibers comprising means for flowing a plurality of streams of glass from a supply body of molten glass with adjacent streams individually accessibly spaced laterally from each other in a row, means for attenuating the streams to form rods of glass including a pair of rolls spaced from the supply means in the general direction of flow of the streams and engageable with opposite sides of the rods, a guide having a section supported at the side of the rolls facing the supply means and having a second section supported at the opposite side of the rolls, said sections havin aligned grooves for respectively receiving the glass rods and the grooves in the second section converging from the rolls to substantially reduce the lateral spacing between adjacent rods and render said rods individually inaccessible, and a tensioning means for the rods between said supply means and said guide.
2. Apparatus for making glass fibers comprising means for flowing a plurality of streams of glass from a supply body of molten glass with adjacent streams individually accessibly spaced laterally from each other in a row, means for attenuating the streams to form rods of glass including a pair of rolls spaced from the supply means in the general direction of flow of the streams and engageable with opposite sides of the rods, an upper guide member supported at the side of the rolls facing the supply means, a. lower guide member supported at the opposite side of the rolls, said guide member having aligned grooves for respectively receiving the glass rods, the receiving ends of the grooves in the upper guide member being flared outwardly to facilitate threading the individual rods into the guide and the grooves in the lower member converging from the rolls to substantially reduce the lateral spacing between adjacent rods and render said rods individually inaccessible, and means between said upper guide and said supply means for applying tension to the rods.
3. Apparatus for making glass fibers comprising means for producing a relatively wide blast of gas having a temperature exceeding the softening temperature of glass and having a velocity high enough to attenuate heat softened glass to form fibers, a feeder supported above the blast and adapted to contain a supply of molten glass, said feeder having a plurality of restricted orifices spaced laterally from each other in a row extending transversely of the blast and through which the molten glass flows in the form of individually accessible streams, means for attenuating the streams to filaments, a guide supported between the feeder and the attenuating means and having a plurality of parallell arranged grooves for respectively receiving the filaments resulting from said streams, the grooves being spaced from each other distances corresponding to the spacing between adjacent orifices in the bottom wall of the feeder, a second guide supported between the attenuating means and the blast, said second guide having grooves corresponding in number and spacing at the entrant end to the grooves in said first guide, and said grooves converging from the entrant end to the delivery end to occupy a distance approximating the width of the blast and render said filaments individually inaccessible.
4. Apparatus for making glass fibers comprising means for producing a relatively wide blast of gas having a temperature exceeding the softening temperature of glass and having a velocity high enough to attenuate softened glass to form fibers, a feeder supported above the blast of gas and adapted to contain a supply body of heat softened glass, said feeder having in the bottom wall a plurality of orifices spaced laterally from each other in a row extending across the width of the blast and occupyin a distance substantially greater than the width of the blast, means for attenuating the streams of glass issuing from the orifices to form individually accessible rods of glass, an upper guide member supported between the feeder and the attenuating means and having a plurality of grooves for respectively receiving the glass rods, said grooves spaced from each other distances which correspond to the spacing between adjacent orifices in the bottom wall of the feeder to maintain a parallel relation between said rods, and a lower guide member supported between the attenuating means and the blast and having a corresponding number of grooves, said grooves having the entrant ends spaced in alignment with the grooves in said upper guide member and having the delivery ends occupying a space approximating in length the width of the blast and render said rods individually inaccessible.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,210,161 Berne-Allen, Jr Aug. 6, 1940 2,457,777 Holtschulte et a1. Dec. 28, 1948 2,460,899 Modigliani et a1. Feb. 8, 1949 2,489,242 Slayter et a1. Nov. 22, 1949 FOREIGN PATENTS Number Country Date 767,550 France July 20, 1934