CA1075908A - Method and apparatus for making fibers from thermoplastic materials - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Method and apparatus for the production of fibers from attenuable materials, particularly molten glass, by the technique known as toration, i.e., the fiberizing tech-nique according to which the attenuable material is delivered into the zone of interaction established by the transverse penetration of a gaseous jet into a larger gaseous blast.
According to the disclosed technique, a tertiary jet is also employed.

Description

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PROCESS AND APPARATUS FOR MAKING FIBERS
FROM T~-lERMOPLASTIC MATF.RIALS

In our Canadian application No. 196,097, filed March 27, 1974, there is disclosed a new technique for produc-ing fibers from attenuable materials, such as molten glass.
Thus, in said prior application a gaseous jet is arranged to penetrate transversely into a larger gaseous blast in order to establish a zone of interaction, and the attenuable material such as the molten glass is admitted into the zone of inter-action and this results in attenuation of the attenuablematerial thereby forming fibers or filaments. For introduction of the glass or other attenuable material into the zone of inter-action, a stream of the molten glass is delivered fro~ a glass supply orifice usually located in a position which, with reference to the blast, is downstream of the jet. This fiberization technique is referred to as "toration" in the prior application above referred to.

The present invention is concerned with improvements and variations both in the apparatus and in the methocl for forming fibers by toration, i.e. by techniques of the kind disclosed in the prior application above identified and also by the modified toration techniques herein disclosed, which are applicable to attenuable materials generally, particularly heat-ed softenable materials such as glass.

Before referring to the accompanying drawings, certain aspects and features of the present invention are preliminarily and generally described,as follows.

One aspect of the present invention relates to the employment of novel arrangements and construction of plate . ' . ' : , ~ ~

`` 1~75908 or wall elements positioned at the boundary of the blast down-stream from the location of the point of entry of the molten glass or other attenuable material. Downstream plates of cer-tain types are disclosed in a number of figures of the drawings of the prior application above identified, for instance in Figures 10 and 11. Such a downstream plate may be positioned at an angle to the blast which is indicated at 12A in the prior ap-plication and also in the present application, in which event the downstream plate acts to deflect the blast, as clearly ap-pears in Figures 10 and 11 of said prior application, and alsoin certain figures of the present application as will further appear.

In fiberization where such a downstream plate is em-ployed, the fibers some times tend to adhere to the plate, and this is particularly true where the plate is positioned at an angle in order to deflect the blast.

; One of the purposes of the technique according to the present application is to reduce tendency for fibers to adhere to and accumulate upon a downstream plate or wall element.
For this purpose, the arrangement provides for the introduc-tion of a tertiary gas supply, for instance the introduction of air into the blast in the region of the upstream edge of the downstream plate and in a position, with respect to the flow of the blast, which is just downstream of the orifice through which the molten glass is admitted. Such introduction of air at the upstream edge of the plate results in development of ; a boundary layer of air at the surface of the plate presented to the blast, and this tends to avoid adherence and build up of glass upon the surface of the plate.

In equipment having a plurality of fiberizing stations

2-~ ., `10759(~8 spaced from each other transversely of the blast and each includ-ing both a secondary jet penetrating the blast and an orifice for introduction of the molten glass, the arrangement for intro-ducing the tertiary gas may comprise either a series of individual jets, each one aligned with one of the fiberizing stations, or a gas admission slot extended transversely of the blast.
In either event, the admission of the tertiary gas tends to establish a curtain or boundary layer of gas at the surface of the downstream plate presented to the blast, and also has a tendency to cause the stream of molten glass introduced through the glass orifice to penetrate farther into the blast before the fiber is drawn from the glass stream.

According to another aspect of the arrangements dis-closed in certain figures of the present application, a unitary structure is provided in the region in which both the secondary jet and the glass are delivered to the blast. Certain purposes of this unitary structure are related to the problem of estab-lishing and maintaining accurate alignment of the secondary jet and the glass admission orifice in the direction upstream and downstream of the blast, and this problem is of a special - importance in equipment embodying a multiplicity of fiberizing centers, each including a secondary jet and a glass orifice, and arranged in a series spaced from each other transversely of the blast.

In toration, i.e. the fiberizing technique utilizing the interaction of a jet and a blast to effect attenuation and fiberizing, it is important, for uniformity of the fibers pro-duced, that in each fiberization center the secondary jet and the glass admission orifice be accurately aligned with each other upstream and downstream of the blast. One technique for achieving accuracy of alignment in the upstream and downstream

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sense as disclosed in the prior application referred to is to employ a series of separate secondary jets, but only a single glass orifice, the orifice being in the form of an elongated slot extended transversely of the blast in a position which, with respect to the blast, is downstream of the jets, as shown for example in Figures 12, 12A, 13A and 13B of said prior ap-plication. In the arrangement using the slot, under the influence of the individual secondary jets, the molten glass is delivered to the blast from the slot only at spaced points transversely of the blast, one such point being accurately located downstream of each of the secondary jets.

According to the arrangements shown in the drawings and described hereinafter, instead of utilizing a glass admission slot, a crucible or bushing for the glass is provided with a 15 series of transversely spaced glass admission orifices. This crucible or bushing further is provided with a plate or wall structure adjacent to the glass admission orifices at the side thereof which, with relation to the flow of the blast, is up-stream of the glass admission orifices. This upstream plate 20 is formed unitarily, preferably integrally with the crucible or bushing, and is provided with a series of bores or apertures formed therein, one aligned with each one of the glass admission orifices. By providing a common or unitary structure in which both the glass admission orifices and the secondary jet admission orifices are formed or drilled, accurate alignment of each pair of orifices is more readily achieved. Because of the proximity of these orifices the temperature of the carrier jet influences the temperature of the glass stream, which makes possible control of glass stream temperature by regulating the temperature of the carrier jet.

4.

- iO75~08 In combination with the upstream plate formed unitarily with the crucible or bushing, this arrangement also provides a new and improved form of device for delivering the secondary jets through the orifices provided in said unitary plate. This improved arrangement includes the use of individual tubes from which the secondary jets are discharged, such tubes being of slightly smaller outside diameter than the diameter o-E the secondary jet orifices in the unitary upstream plate, and these jet tubes project into but not through the jet oriEices. Prefer-ably the jet tubes are mounted in groups, For instance, inan arrangement in which the bushing is provided with approximate-ly 80 glass admission orifices, the tubes are arranged and mounted in groups of approximately 20 and each such group is also prefer-ably separately supplied with the jet gas. Although, for most glass formulations it would be contemplated to employ platinum alloys for the unitary crucible and upstream plate, the arrange-; ment described just above with the provision of separate jet tubes, permîts the fabrication of the unitary plate and crucible of platinum alloys, while the tubes and the associated mounting and gas supply means are fabricated from less expensive metals,such as stainless steel. It is also of advantage, especially where the crucible and upstream plate are formed of platinum and the jet tubes are formed of stainless steel to provide for the mounting and supply of the jet tubes in groups representing a subdivision of the total associated with a multiple orifice bushing, because subdivision into groups more readily accommodates differential thermal expansion and contraction as between the structure of the crucible on the one hand and the structure of the jet tubes and the jet mounting and supply structures on the other hand.

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~75908 For purposes of protection of the jet tubes in the region where they project into the jet apertures in the upstream plate which is unitarily formed with the crucible or bushing, the individual jet tubes are desirably coated with an insulating material, for instance alumina.

The various figures of the accompanying drawings are briefly described as foliows:

Figures 1 to 8 inclusive illustrate various parts of an embodiment according to the invention, incorporating pro-vision for introducing a tertiary jet or gas, and in this groupof figures -:~ Figure 1 is an elevational view partly in vertical section showing glass supply means, means for developing a blast ~:
and secondary jet, and further for introducing tertiary gas in the manner to be described;
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Figure 2 is a plan view of certain parts taken asindicated by the line 2-2 on Figure 1;

Figure 3 is an enlarged vertical sectional view of the crucible or bushing, with an integral plate, this view also showing the association of the secondary jet and tertiary gas admission devices, this view being taken as indicated by the line 3-3 on Figure 4;

Figure 4 is a plan view looking upwardly at certain parts shown in Figure 3, Figure 4 being taken as indicated by the line 4-4 on Figure 3;

Figure 5 is a somewhat diagrammatic view of some parts shown in Figure 3 and particularly showing the fiberizing action achieved by the employment of not only the blas~ and secondary jet but also of the tertiary gas admission means;

Figure ~ is an isometric view of certain gas supply and distributing means employed for supplying gas to the second-ary jets;

Figure 7 is a horizontal sectional view through cer-tain of the parts at the fiberizing centers, the central portion of this view being broken out and the view showing the arrangement of certain parts making up a multiple center fiberizing installa-tion; and Figure 8 is an isometric view of equipment employed ; .
to mount a plurality of secondary jet tubes and supply such tubes with jet gas.

Figures 9 and 10 are views illustrating a modified :~ :
form of equipment for introducing the tertiary gas, Figure 9 being taken as indicated by the section line 9-9 on Figure 10 and Figure 10 being taken as indicated by the section line 10- :
10 on Figure 9. -Figures 11 and 12 are fragmentary views taken in a manner similar to Figure 3, but illustrating additional embodiments of the equipment for introducing the tertiary gas.

Figures 13 and 14 are views illustrating still an-other arrangement of parts for establishing fiberizing centersarranged according to the present invention, Figure 13 being , :

~C~7S908 taken in the same general manner as portions of Figure 1, and Figure 14 being a fragmentary plan view looking up at certain of the parts shown at Figure 13.

The embodiment illustrated in Figures 1 to 8 is des-cribed just below.

In the following description a few of the reference symbols used in the prior application referred to above are also employed in this description for corresponding items, but most of the reference characters are new ones, beginning with number 200.
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The general arrangement (see particularly Figures 1 to 4) includes a fiberizing crucible or bushing 200 associat-ed with a glass supply forehearth 201, although it is to be understood that instead of supplying the molten glass from a forehearth of a glass forming furnace, a resistively heated melting crucible may be employed to melt and supply the forming glass, The crucible of Figures 1 to 4 is provided with a series of glass discharge orifices 37, adapted to deliver the glass into the zone of interaction between a primary jet or blast and a series of secondary or carrier jets, one such carrier jet being associated with each glass supply orifice in order to establish a plurality of fiberizing centers. The blast is indicated by the arrow 12A (see Figure 5) and the jets are delivered from jet supply tubes (to be described hereinafter) through jet orifices 36 (also referred to more fully hereinafter).

8.

1~7S908 The blast is delivered from the duct 202, the blast being generated by combus~ion of fuel in the combustion chamber 203 ~see Figure 1) which may be supplied with a mixture of gas and air at 204.

A burner 205 supplied with a mixture of gas and air at 206 provides the gas to be delivered through the orifices 36 through the jet tubes above referred to. The arrangement of these parts which establishes each of the fiberizing centers is shown to best advantage in Figures 3 and 5. As there illu-strated, it will be seen that jet tubes 207 which are supplied from the burner 205 in the manner to be explained below, pro-ject into the apertures 36 and deliver jets or gas streams trans-versely into the blast 12A discharged from the duct 202. As shown in the embodiment of Figures 1 to 8, the jet orifices 36 are formed in a wall or lip 208 lying adjacent to the boundary of the blast 12A and formed unitarily, preferably integrally with the crucible 200.

Each fiberizing center provided as just described functions in the general manner fully disclosed in our earlier application above identified, and the parameters including the kinetic energy of the blast and the secondary jet in the operation-al area thereof and the temperatures and velocities of the blast and jet, as well as the temperature of the glass, relationship between the size of the glass and the jet orifices, the spacing thereof and the like, may all conform with various parameters set out herein and also in the above identified application.
It is here mentioned that the blast should be of larger section than the jet and that the kinetic energy of the jet per unit of volume should be greater than that of the blast in the operational area thereof. With gaseous jets and blast this energy relationship 9.

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1~759~)B

is desirably provided by employment of a jet of hi~her velocity than the blast.
One of the improvements involved in the modification here under consideration relates to the employment of a "down-stream" wall or plate element of the general kind shown in Figures10 and 11 of said earlier application. Such a plate is referred to as a "downstream" plate because it is situated, with respect to the direction of flow of the blast 12A, in a position down-stream of the fiberizing center, i.e. downstream of the glass orifice 37, which in turn is located downstream of the secondary jet orifice 36. The downstream plate is especially illustrated in Figures 1, 3 and 5, being identified in general by the ref-erence numeral 209. As seen in Figure 1, the downstream plate is mounted by means of joint linkage 210 which provides for adjustment of the position and inclination of the plate. In these figures, the plate 209 is adjusted to a position which is inclined so as to deflect the blast after it passes the glass discharge orifice.
The downstream plate is provided with a passage 211, with connections 212, providing for the circulation of a cooling medium, for instance water, through the channel 211 thereby effecting cooling of the downstream plate.
As mentioned above, the employment of a wall or plate downstream of the fiberizing centers some times results in tendency for the fibers to contact the plate and thereby tends to build up deposits of glass upon the surface of the plate presented to the blast. According to the present improvements, this tendency is substantially eliminated by dynamically exerting a localized action affecting the flow of the blast by introducing air, pre-ferably in the form of a boundary layer along the lower surfaceof the downstream plate or along the leading or upstream edge of the plate. The air or gas for this purpose may for convenience ; be referred to as the "tertiary jet". The means for dynamically 10 .

exerting the localized action af-fecting the flow of the blast may for example comprise structure at the boundary of the current formed by the interaction of the blast and jet, said structure including means for bringing an additional gaseous jet into con-tact with the interaction current.
In the embodiment of Figures 1 to 8, the leading edge213 is positioned in slightly spaced relation to the lower portion of the crucible 200, so that a slot is provided between the crucible and the leading edge of the plate, through which slot tertiary gas may be supplied in a region which, with relation to the direction of flow of the blast, is downstream of the glass orifices 37. The plate 209 has a channel 214 formed therein, with connections 215 for supply of the tertiary gas, for instance air. A series of ports 216 communicates with the supply channel 214 and delivers air in an upstream direction toward the leading edge of the downstream plate, thereby supplying the air for entry through the slot adjacent to the crucible. In order to close the space between the crucible and downstream plate and thus assure that the tertiary gas will not escape and will be delivered through the slot at the leading edge of the plate, a sheet metal plate 217 is connected with the mounting structure 218, with the lower edge of the plate turned upwardly to engage the lower wall of the crucible, and thereby provide a space to accommodate a fibrous insulating material 219 of high thermal resistance, such as aluminum oxide fiber. The enclosure plate 217 may advantageously be formed of stainless steel having some appreciable resilience and is configured to establish contact with the plate 209, thereby closing the space between the crucible and the`plate. With this arrangement, and with the enclosure 217 made of resilient material, the downstream plate may be adjusted in position in the manner described above while retaining - engagement of the enclosure 217.
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10'75908 The action of the tertiary jet is indicated in Figure

5 of the drawings, in which flow lines indicate not only the blast 12A and the secondary je~ from the jet tube 207, but also the tertiary jet delivered from the passage 216 to the leading edge of the plate, at which point the tertiary air passes through the slot and enters the system at the boundary of the blast, producing a current or boundary layer at the lower surface of the plate 209. The equipment includes a plurality of fiberizing centers of the kind shown in Figure 5 spaced from each other transversely of the blast. It is contemplated that a tertiary gas passage 216 be provided in alignment with each secondary jet orifice 36 and its associated glass admission orifice 37.
With a plurality of tertiary gas delivery passages, the tertiary gas from the several passages tends to merge and thus form a more or less complete curtain of gas as the flow passes through the slot and follows the lower surface of the downstream plate at the boundary of the blast. Because of this, the fibers being formed are effectively prevented from contacting the surface of the downstream plate.

It is also pointed out that the provision of the tertiary gas supply channel 214 and the flow of the tertiary gas over the surfaces of the downstream plate assists in cooling *he plate, so that the action of the tertiary gas, together with the action of the cooling medium circulating through the channel 211 will maintain the plate at a relatively low temperature, which is also of benefit in avoiding sticking of glass to the surface of the plate.

In an installation in which a large number of fiber-izing centers are provided in spaced relation transversely 12.

1q~75908 of the blast, for instance in the neighborhood of 80 fiberizing centers, it is preferred to sectionalize the downstream plate.
As seen in Figures 2 and 7, the downstream plate associatedd with the multiplicity of fiberizing stations there shown, is s sectionalized and formed in three sections, each one of which is provided with a water cooling channel 211 and a tertiary gas supply channel 214, respectively having water circulating and a;r supply connections as already described. Forming the plate in such sections facilitates effective and accurate circu-1~ lation of the cooling water and assures accurate distributingof the tertiary gas supply, thereby assisting in maintaining the desired operating conditions within close tolerances.

Turning now to the arrangement of the secondary jets as embodied in Figures 1 to 8, it is again pointed out that an upstream plate 208 is preferably formed integrally with the crucible 200, this structure desirably being made of a pla-tinum alloy when employing typical glass formulations used for fiber manufacture. For the purposes of ensuring accurate fiber formation, and particularly for the purpose of assuring uniformity of fiber formation at each of the multiplicity of stations, it is of importance to provide accurate upstream-downstream alignment of the secondary jet orifices 36 and the glass admission orifices 37. In Figures 12, 12A, 13A and 13B
of the earlier application above identified, this accuracy of upstream-downstream alignment of the secondary jet and the stream of glass to be fiberized is automatically achieved by the employment of an elongated slot for the admission of glass, rather than a series of separately formed glass admission orifices, as has already been noted above. The arrangement shown in Figures 1 to 8 also provides for accuracy of alignment of the secondary jets with the streams of glass, but in this case, 13.

the accuracy of alignment is provided for notwithstanding the use of separate glass admission orifices. This accuracy is assured by virtue of the unitary formation of the wall or upstream plate 208 with the crucible 200. Since both the secondary jet orifices and the glass orifices are drilled in the same unitary structure, accuracy of alignment is provided for and will be maintained even under varying conditions of thermal expansion and contraction of various parts of the structure.

This accuracy of alignment is further facilitated 10 by virtue of certain other arrangements included in the embodi-ment shown in Figures 1 to 8. Thus, from examination of Figures 2, 3, 4, 7 and 8, it will be seen that each secondary jet is delivered from a jet tube 207 which extends into the orifice 36, the jet tube 207 being of slightly smaller diameter than lS the diameter of the orifice 36. The jet tubes 207 are subdivided into groups, four such groups being shown in the embodiment illustrated and each group is mounted upon a jet fluid manifold 220 which is connected with the supply pipe 221. By this subdi-vision of the total number of jet tubes and the separate mounting of each group, thermal expansion and contraction of the manifold which mounts and supplies each group, is more readily accommodated ; than would be the case if all of the jet tubes were mounted on a single structure extended throughout the entire series of fiberizing stations. Moreover, by utilizing jet tubes 207 projecting into individual drilled jet orifices 36, and by employing jet tubes of slightly smaller outside diameter than the diameter of the orifices, additional clearance is provided for accommodation of expansion and contraction. The grouping `~ of the jet tubes and the arrangement and mounting thereof as just described in order to provide for accommodation of expansion and contraction is particularly importannt where, as here con-templated, the crucible 200 and the upstream plate 208 are 14.

` iO7S908 formed of platinum alloys and the jet tubes and associatedparts are formed of some other less expensive metal such as stainless steel, because these different metals have different coefficient of thermal expansion and contraction.

As best seen in Figure 8 each group of jet tubes 207, together with its mounting manifold 2Z0 and the associated supply connection 221 form a structure generally resembling a rake, and this structure is adapted to be mounted at the base end of the supply connection 221. As seen in Figures 1 and 2, the supply connections 221 are adapted to communicate with the burner 205 for developing the secondary jet gas, and preferably provision is made for introducing air into the gas stream entering each supply connection 221. This is accom-plished by supply means in the form of a fitting 223 (see also Figure 6) interposed between the burner chamber 205 and the mounting plates 222 for the supply connections 221 for the groups of jet tubes. This "air diluter" is provided with air supply pipes 224 connected therewith through the tubes 225, there being several of the supply pipes 224 distributed along the length of the air diluter, the tubes 225 delivering the air to the passages 226 in the air diluter. One such passage 226 is provided for each of the groups of secondary jet tubes, and in this manner the jet tubes are supplied with diluted products from the combustion chamber 205. The dilution of the gases coming from the combustion chamber 205 is important because of the use of those gases in the jet tubes 207 and the contemplated employment of less expensive metal than the platinum alloys used for the crucible. As already indicated, stainless 15.

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1.f)7S~3~8 steel is appropriate for the jet tubes 207, but will not with~
stand the temperatures generated in the combustion chamber 205 without dilution, As will be seen from Figures 2, 4 and 7, there is included an "outboard" secondary jet orifice 36 and a secondary jet tube 207 laterally offset beyond each end of the glass admiss-ion orifices 37~ This is in conformity with the disclosure of other multiple orifice arrangenents described in the prior ap~
plication above identified and assures uniform fiberi~ing activity at the glass admission orifices at the opposite ends of the series~ In addition to this provision, it is contemplated according to arrangements disclosed herein that a similar provi-sion be made with respect to the tertiary gas admission passages, : In other words, as will be seen from Fi~ures 2, 4 and 7, there is a tertiary gas admission passage located in offset relation beyond each end of the series of glass admission orifices, this arrangement being provided for reasons similar to those referred to in connection with the offset or r'outboard" secondary- iet orifices, A modified form of downstream plate and tertiary jet supply is illustrated in F.igures 9 and 10.; Here the down-: stream plate is shown at 227, being provided with a cooling mediunl circulation channel 228 with connections 229, and also with an air supply channel 230, ~rith supply connections 231.
Here the individual passages or ports 232 which deliver the tertiary air from the supply channel 230 connect with the base of a groove or slot 233 having an open edge presented toward and just above the leading edge 234 of the downstream plate.
It will be understood that this structure is adapted to be .~

1~75908 mounted in relation to the fiberizing stations in the same general manner as described above with respect to Figure 1.
The downstream plate of Figures 9 and 10 is also adapted to cooperate with a structure for closing the space between the 5 downstream plate and the crucible in the same manner as indi-cated at 217 and 219 in Figures 1, 3 and 5. A slot such as shown at 233 may be employed to assist in the spreading of the tertiary gas along the upstream edge of the plate, and thereby assist in providing a blanket of the tertiary gas between 10 the surface of the plate and the blast.

Still another modified form of construction of the downstream plate and the tertiary gas supply is illustrated in Figure 11. As here shown, the lower portion of the crucible 200 is of somewhat modified configuration and the downstream 15 plate 234 is also of modified shape adapted to cooperate with the lower portion of the crucible in the manner mentioned just below. The plate 234 is provided with a cooling medium circulat-ing channel 235 with connections 236 and the tertiary gas supply channel 237 has supply connections 238, with passages 239 which 20 communicate with a slot like chamber or passage formed between the leading edge portion of the plate 234 and the bottom portion of the crucible. Sealing means is also provided between the plate and the crucible to insure flow of the tertiary gas in the desired direction and out of the slot at the leading edge 25 of the plate, as will now be understood.

Still another modified arrangement of the downstream plate is shown in Figure 12. In this embodiment, the crucible is again indicated at 200, having an upstream plate 208 with 17.

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1~75908 orifices 36 cooperating with jet tubes 207. ~lere the construction of the downstream plate 209 is essentially the same as that described above with reference to Figures 1 to 8, but the system for sealing the space between the plate and crucible is different.
Thus, the downstream plate is provided with an upper metallic closure strip 240 which is extended along the length of the plate 209 and cooperates with the lower portion of the plate in defining an elongated slot for admission of the tertiary gas into the blast. This structure is here thermally isolated from the crucible by means of a layer of insulating material such as indicated at 241 overlying the wall 240. The insulation 241 may for example comprise a layer of material of high thermal resistance, such as alumina. Insulation of this kind and also the insulation 219 described above is of advantage in the equip-ment in order to minimize heat loss from the crucible.

In all of the embodiments described above, whereverthe jet tubes 207 are employed projecting into orifices formed in a structure integral with the crucible, it is desirable to provide thermal insulation between the jet tubes and the jet orifices. This is advantageously provided by applying a thermal insulating coating to the tubes, for instance a coating of alumina. This also diminishes heat loss from the crucible and in addition will serve to protect the metal of the jet tubes.

All of the arrangements described just above are also adaptable to an installation of the general kind shown in Figure 1 in which the crucible is mounted below a glass 18.

1~'75908 supply forehearth indicated at 201, the crucible being isolated or insulated from the glass supply structure by a ceramic insula-tion element 242, in which a tube 243 for a cooling medium is embedded (see Figures 1 and 2). I~igh temperature fibrous insulating material 244 is also desirably used as indicated at the lower side of adjoining surfaces of the forehearth in order to retard thermal loss in this region.
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For at least some purposes, it is also preferred to provide electrical connections such as indicated at 245, connected to and extended from the ends of the crucible 200 and provided for resistive heating of the crucible.

Still another embodiment of equipment incorporating tertiary gas supply means is disclosed in Figures 13 and 14.
In this embodiment the glass supply forehearth or the like is indicated at 246 and the crucible or bushing at the bottom : is indicated at 247. The glass supply orifices are again indicat-ed by the number 37 and in this case the secondary jets are ; supplied through orifices 36 provided in the projections 248 which extend from the secondary jet gas supply manifold 249.
: 20 A supply conduit 250 is connection with the manifold 249.

The blast 12A is delivered from the structure 251, with the upper boundary of the blast close to the secondary jet and glass orifices 36 and 37.

At the downstream side of the orifices 37, a down-stream plate structure indicated at 252 is provided, this struc-ture being hollow to provide a manifold 253 supplied by supply , 19.

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' ~7S~8 duct 254. The manifold is provided with projecting nozzle structures 255 having orifices 256 for discharge of the tertiary air in a position which, with respect to the direction of flow of the blast is downstream of the fiberizing center established by the glass and secondary jet orifices.

As is shown in Figure l4, the secondary jet orifices, the glass supply orifices and the tertiary gas orifices are arranged in groups aligned with respect to each other in the upstream and downstream sense, and each group providin~ a fiberiz-ing center.

It will be noted that in the arrangement of Figures13 and 14, a downstream plate is provided without employing any circulation passage for a cooling liquid, the arrangement being such as to provide for cooling of the downstream plate by virtue of the hollow construc.ion of the plate and the flow of theairthrough the interior hollow of the plate.

; With regard to the operation of the fiberizing system when employing tertiary gas as herein disclosed, it is pointed out that the air employed may have a pressure of the order of 0.5 to 2 bars, preferably between about 0.8 and 1.2 bars.

In an installation having about 80 fiberizing stations as in the embodiment of Figures 1 to 8, the air flow used for the tertiary gas supply may be of the order of 15 to 30 m3 per hour, preferably about 17 to 25 m3.

The kinetic energy of the tertiary jet should be considerably lower than the kinetic energy of the secondary jet.
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Claims (25)

The embodiments of the invention in which an ex-clusive property or privilege is claimed as follows:

1. A method for making fibres from attenuable material comprising establishing a gaseous blast directed in one path, establishing a gaseous carrier jet transversely to the blast of smaller cross section than and which penetrates the blast, introducing the attenuable material into the blast by feeding a stream of the attenuable material into a position, which, with reference to the blast, is adjacent and downstream of the carrier jet, and dynamically exerting a localized action affecting the flow of the current resulting from the blast and jet.

2. A method as defined in Claim 1 in which the flow affecting action is applied so as to reduce tendency for adherence of attenuable material upon structure adjacent to the path of fibre movement.

3. A method for making fibres from attenuable mater-ial comprising establishing a gaseous blast directed in one path, establishing a gaseous carrier jet transversely to the blast of smaller cross section than and which penetrates the blast, introducing the attenuable material into the blast by feeding a stream of the attenuable material into a position, which, with reference to the blast, is adjacent and downstream of the carrier jet, and introducing an additional current of gas downstream of the zone of introduction of the stream of attenuable material.

4. A process according to Claim 3, wherein the addi-tional current contacts the current resulting from the blast and the jet in the immediate vicinity of the stream of attenuable material.

5. A process according to Claim 3, wherein the additional current flows along a surface extending downstream of the zone of introduction of the stream.

6. A process for the manufacture of glass fibres from molten glass, comprising creating a main gaseous current directed in a predetermined direction, creating a gaseous carrier jet of smaller cross-section than the main current and causing the jet to enter the main current transversely to the latter, introducing molten glass into the main current by con-ducting a stream of molten glass into the main current at a point contiguous and downstream of the carrier jet in the direction of movement of the main current, and bringing into contact with the resultant current of interaction between the main current and the carrier jet an additional gaseous current at a point downstream of the zone of introduction of the molten stream.

7. A process according to Claim 1, 3 or 6, wherein the temperature of the zone of fibre formation is controlled by varying the temperature of the carrier jet before it pene-trates the blast or main gaseous current.

8. Equipment for making fibers from attenuable material comprising means for establishing a gaseous blast, means for establishing a gaseous jet of smaller cross-sectional dimension than the blast, with the jet directed transversely of and penetrating into the blast and thereby developing a zone of interaction between the blast and jet, supply means for effecting delivery of the attenuable material so that it will enter said zone of interaction, and dynamic means exerting a localized action affecting the flow of the blast downstream of said zone of interaction.

9. Apparatus according to Claim 8, wherein said dynamic means comprises means for delivering an additional current of gas and is arranged so that this additional current contacts the boundary of the blast in the immediate vicinity of said zone of interaction.

10. Apparatus according to Claim 9, comprising plate means extending downstream of the zone in which the attenuable material enters the fiberizing zone, the plate means being arranged so that the additional current flows in contact with a surface thereof downstream of the zone in which the attenuable material enters the fiberizing zone.

11. Apparatus for carrying out a process according to Claim 6, comprising:-means for supplying molten glass, which means has an outlet orifice; means for creating a main gaseous current which is oriented in a given direction, means for creating a carrier gas jet directed transversely to the direction of the main current and entering the latter at a point upstream with respect to the outlet orifice, the jet being of smaller cross-section than the main current;
plate means situated downstream of the carrier jet in the direction of propagation of the main current; and means for introducing an additional gas current into the main current downstream of the glass outlet in the region of the upstream edge of the plate means.

12. Apparatus according to Claim 11, wherein the plate means contains a gas supply including orifices in the plate means directed towards the leading edge of the plate means and serving to produce the additional current in the region of the leading edge.

13. Apparatus according to Claim 12, wherein the plate means has a conduit for circulation of cooling fluid.

14. Apparatus according to Claim 11, comprising a plurality of gas duct orifices spaced apart transversely with respect to the main current, with separate means for creating the additional current upstream of each outlet, and in which the means for introducing the additional current in the region of the upstream edge of the plate means comprises a separate outlet downstream of each glass outlet.

15. Apparatus according to Claim 11, wherein a plurality of spaced glass outlets are arranged transversely of the main current; means are provided for creating a carrier gas jet upstream of each glass outlet and the means for introducing an additional gas current in the region of the upstream edge of the plate means comprise a slot extending along the glass outlets.

16. Apparatus according to Claim 15, wherein the plate means contains a feedpipe and individual channels between the feedpipe and the slot, each channel being downstream of a corresponding glass outlet.

17. Apparatus for the manufacture of fibres from thermoplastic attenuable material, comprising:-means for creating a main gaseous current; means for producing a gaseous jet of smaller cross-sectional dimension than the current; the jet being directed transversely to the current and entering the current to produce a zone of interaction, the kinetic energy of the jet per unit volume being greater than that of the current in the said zone; feed devices arranged to introduce softened thermoplastic material into the zone; and dynamic means exerting a localized action affecting the flow of the current resulting from the main current and jet downstream of said zone of interaction.

18. Apparatus according to Claim 17, in which said dynamic means comprises means for delivering an additional current to the boundary of the main current downstream of the zone so as to prevent adherence of fibres to structural members adjacent the path of the fibres.

19. Apparatus according to Claim 17, in which said dynamic means comprises structure at the boundary of the current resulting from the interaction.

20. Apparatus for the manufacture of glass fibres from molten glass, comprising means for creating a main gaseous current; a structure at one side of the main current and constituting a boundary of the main current; means for conducting a gaseous carrier jet of smaller cross-sectional dimension than the main current transversely through said structure and into the main current; means for conducting a stream of molten glass through said structure and to the main current in a zone directly adjacent the carrier jet and downstream thereof with respect to the main current; and means for bringing an additional gaseous jet into contact with the current resulting from the interaction of the main current and the carrier jet at a point downstream of the zone of interaction and contiguous to the point of introduction of the stream of molten glass.

21. Apparatus according to Claim 20, having means for introducing a plurality of carrier jets and a plurality of streams of molten glass at points spaced apart from one another transversely of the main current, as well as separate apertures spaced for introducing a plurality of additional gas jets downstream of the glass streams.

22. Apparatus according to Claim 20, having means for introducing a pluraity of carriet jets and a plurality of streams of molten glass at points spaced apart from one another transversely of the main current, an outlet slot for additional gas extending transversely to the main current for the introduction of an additional gas current downstream of the glass streams.

23. Apparatus according to Claim 20, comprising at least one aperture in the structure aligned in the direction of the current with said means for conducting a stream of molten glass and, within each aperture, an outlet tube for delivering a carrier gas jet.

24. Apparatus according to Claim 23, wherein the tube is surrounded with insulating material.

25. Apparatus according to Claim 20, wherein the glass flows from an electric resistance heated container.