FI59579C - FOER REFRIGERATION FOR FIBER FRAMSTERING AV FIBER AV THERMOPLASTIC MATERIAL SAOSOM GLAS - Google Patents

Description

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France-France (FR) 7501 + 970 (71) Saint-Gobain Industries, 62, Bd Victor Hugo, F-92209 Neuilly sur Seine, France-France (FR) (72) Marcel Levecque, Saint-Gratien, Jean A. Battigelli , Rantigny,

Dominique Plantard, Rantigny, France-France (FR) (74) Berggren Oy Ab (54) Method and apparatus for making fibers from thermoplastic materials such as glass - Förfarande och anordning för framställning av fibrer av thermoplastiskt material säsom glas

The invention relates to a method and apparatus for converting thermoplastic materials, such as glass, into fibers, comprising providing a gas stream and a gas jet called a secondary jet with a jet direction such that it encounters a gas stream and kinetic energy sufficient to penetrating into the gas stream, whereby an interaction zone is formed in the vicinity of the point where the gas jet penetrates the gas stream, and the thermally softened material is led to the interface of the gas stream through which it penetrates, entering the interaction zone, causing the material to stretch and Such a method is the subject of FI patent publication 57247.

The present invention is directed to improvements in this method and the equipment used therein, specifically in feeding molten material to the interaction zone.

It has been found that it is advantageous to leave a certain distance between the nozzles and the main current limit. Such a distance makes it easier to adjust the atmosphere surrounding the crucible to which the molten material is introduced, 2 59579. Likewise, such a spacing makes it possible to use certain crucible heating arrangements which could not be comfortably applied to plants where the glass feed nozzle is located exactly at the main current limit.

This distance also makes it possible to create a free space between the source of the softened material and the stream, the existence of which has proved to be very important.

The method according to the invention is mainly characterized in that the main gas stream leaves at a distance from the supply source and that the substance strands are directed to a free space separating the main gas stream from said source along paths encountering the main gas stream in each zone where the secondary jet enters the main gas.

Another particularly advantageous feature of the invention is the secondary jet to form an interaction zone at a point above the upper limit of the main current and at a distance from the glass flow nozzle through this free space to reduce the temperature interaction of the structures from which the glass, main current and secondary jet emerge.

According to the invention, the secondary jet is guided specifically obliquely to the feed direction of the glass.

According to a third feature of the invention, the molten substance flows through said free space under the influence of gravity, the effect of the currents caused by the secondary jet in this free space facilitating the passage of this substance into the interaction zone.

According to the invention, the secondary jet is directed obliquely to the flow direction.

According to another feature of the invention, the free space is increased by curving the main current so that it moves away from the structures downstream of the interaction zone. According to the invention, an additional jet is used for this purpose, which acts on the surface of the main stream which is opposite to the surface to which the glass and the secondary jet penetrate.

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According to another important feature of the invention, the molten material is made to flow in the form of a planar layer and a plurality of secondary jets are used which divide this layer into free space into strands.

More specifically, according to the invention, the molten material is made to pass as a planar layer on a horizontal surface, this layer being passed over a curved surface which causes it to pass freely without material support so as to come into contact with secondary jets which share this layer with free currents. into strands that, under the influence of the same jets and the same currents, pass through the free space into the interaction zone.

According to another feature of the invention, an additional jet, also located in the free space on the upstream side of the molten material strand with respect to the gas flow direction, is arranged to stabilize the strand at the moment it enters the interaction zone.

The apparatus for carrying out the method according to the invention comprises a gas flow generator provided with an outlet, a gas generator providing at least one secondary gas jet with a kinetic energy per unit volume greater than the main gas stream, said gas jet generators having an outlet with a smaller cross-section and directing the secondary jet transversely to the main gas stream to form an interaction zone, and a substance supply source having at least one supply port that feeds the substance into the interaction zone. This device is characterized in that the substance supply opening opens at a distance from the main gas flow interface and is positioned to direct at least one strand of material in the stretchable state into a free space separating the supply source and the main gas flow along a path at the main gas flow in the main gas flow area.

59579 This existence of a free space between the source of the softened material and the main stream, which is an essential feature of the devices according to the invention, not only enables the purposes originally pursued, but also the particularly advantageous devices described below.

According to one feature of the devices according to the invention, the outlet of the secondary jet generating member is located in a free space above the interface above the main stream and is at a distance from the molten material supply opening. According to the invention, the feed opening for the molten material is specifically placed at the top of the free space in such a way that the molten material has to pass through said space by gravity. The secondary jet is preferably oriented obliquely to the direction of flow of the molten material.

According to another feature of the devices according to the invention, they comprise a device for changing the direction of the main current so that the free space between the source of the substance and said current increases.

This change of direction can be promoted by bending the main current-guiding wall so that it moves away from the glass inlet.

Advantageously, the change of direction can also be effected by a blowing member which directs downwards an additional jet which is in contact with the opposite surface of the main current to the surface into which the main current and the secondary jets penetrate.

The invention also relates to particularly advantageous devices comprising a device for feeding molten material in the form of a planar layer, secondary jets which have the function both of dividing this layer into strands and of conveying the strands through the free space to the interaction zone.

According to a particularly preferred embodiment, these devices comprise: - a member for receiving the molten material and on which the material passes, - on the 5 59579 side and directing one or more secondary jets into contact with the layer after the change of direction, which jets divide the layer into strands and cause the strands to flow with the jet currents, and - a main current generating blower located below the secondary jet generating members; that strands of molten material can penetrate the interaction zone between the main stream and the secondary jets.

According to another feature of the devices according to the invention, said additional blowing means are located in the free space on the downstream side of the strands of molten material with respect to the direction of flow of the gas flow. These members direct the additional jets into contact with the strands of molten material to stabilize them at the moment they enter the interaction zone.

Embodiments of the devices according to the invention will now be described, by way of non-limiting example, in connection with the accompanying drawing, in which:

Fig. 1 is a sectional view of a defibering station comprising a device for generating a main stream, a device for generating a secondary jet and a glass feeder, the latter having a glass feed opening located well above the upper interface of the main stream at a certain distance therefrom.

Fig. 2 is a view similar to Fig. 1, but showing another embodiment in which the glass feed opening has a different shape.

Fig. 3 is a schematic diagram showing the shape of a group of feed openings analogous to the glass feed openings of Fig. 2, and further showing their position relative to the secondary shower openings.

Figure 4 is a vertical sectional view of an apparatus comprising a plurality of defibering stations; the view is taken on line 4-4 of Figure 6.

Fig. 5 is a fragmentary view analogous to Fig. 4 taken along line 5-5 of Fig. 6;

Fig. 6 is a view of some of the parts shown in Figs. 4 and 5, but 6,59579 viewed from above, so that this figure shows in detail the relative position of the glass and secondary jet feed openings in the embodiment of Figs. 4 and 5.

Fig. 7 shows a further embodiment of the invention analogous to Fig. 2, but further comprising a device for supplying an additional gas flow to the side of the main stream opposite the glass and secondary jet feed openings.

Fig. 8 is a fully schematic, isometric view showing another device for separating glass and main power supply devices.

Fig. 9 is a schematic view of a defibering station, with some parts shown in vertical section and others in uncut section; this figure shows another glass feeder with which it is separated from the main stream.

Fig. 10 is an elevational view of the embodiment of Fig. 9 seen from the right side of Fig. 9.

Fig. 11 is a view analogous to Fig. 1, but showing the use of a second additional gas jet for the reasons explained below.

In the accompanying drawing, the main current is denoted by reference numeral 12A, and the secondary jet and glass feed openings are denoted by reference numerals 36 and 37, respectively, in the same manner as in the various figures of the above-mentioned French patent publication.

Considering first the embodiment of Figure 1, a crucible is connected at 200 which is connected by a suitable device to a glass source such as a pre-furnace 201. The main stream leaves the structure 202 in a horizontal plane well below the glass crucible 200. The outlet of the secondary jet 36 is the open lower end of the jet tube 203, which is fed from a manifold 204 connected to a burner or other secondary gas jet source by a line 205 · Note that the jet tube 203 is located at an angle to the outlet 36A the aperture is some distance higher than the end of the structure 202. * · · 'current interface. The secondary gas jet and the main stream interact with each other to form an interaction zone, as described in detail in the patent referenced above, which zone is located almost exactly vertically below the glass feed opening 37. The glass is fed in the form of a filament S which descends by gravity from the opening 37 and enters the main gas jet main current interaction zone, whereby defibering and stretching are further provided in the zone as described in detail in said patent publication.

In some of the embodiments shown, including the one shown in Figure 1, the vertical distance between the glass supply opening 37 and the upper interface 12A of the main current 12A may be on the order of 10-100 mm. In addition, the distance between the outlet opening 36 of the secondary gas jet and the interface above the main stream can be of the order of 5-10 mm.

In these embodiments, the distance between the center lines of the orifices 36 and 37, measured in the direction upstream of the main stream 12A, may be 4-10 mm. In addition, due to the location of the defibering station and the distances between the various members forming it, the jet tube 203 and thus the jet leaving it should preferably form an angle with the center line of the main stream 12A. The angle of the secondary gas jet with respect to the center line of the main stream should preferably be less than 90 ° and may be, for example, between about 45-50 ° and 85 °. The most suitable limits are about 75 ° and 85 °. The ratios of angles to distances must be suitable in order to form a zone of interaction between the secondary gas jet and the main stream at a point almost exactly vertically below the glass inlet 37. Likewise, it is most convenient to position the spray pipe 203 and thus also the outlet of the secondary gas jet in such a way that the outlet of the secondary gas jet is located upstream of the glass fiber S with respect to the direction of travel of the main stream 12A. The inclination of the nozzle 203 must cause the secondary gas jet to emerge in a direction generally transverse to the mainstream but having a mainstream flow component which thus promotes defibering and the transition of the stretched fiber in the main flow direction.

Each defibering station, adapted as described in connection with Figure 1, generally operates as described in the above-referenced patent publication. Parameters including the kinetic energy of the main current and the secondary jet in their operating zone, as well as the temperatures and velocities of the main current and the secondary jet as well as the glass temperature and the ratio of the glass to the secondary jet outlets, may all be in accordance with some of these parameters may vary outside the selected limits indicated in said patent publication. For example, and as already mentioned, embodiments of the present invention require that the distance of the glass inlet upward from the nearest interface of the main current be sufficiently large. Other variants may be used, some of which are explained below.

In the devices according to the present invention, it is possible to use less narrow limits for the ratio of the kinetic energy of the secondary gas jet to the kinetic energy of the main stream in their operating zone compared to the devices described in said patent publication. Thus, functionally good results can be obtained by keeping the ratio of the kinetic energies of the secondary gas jet to the main stream substantially in the range of 4: 1-35: 1.

In the devices according to the present invention, the dimension of the outlet opening of the secondary gas jet can be considerably smaller than that used according to said patent publication. In the devices according to the invention, for example, the outlet opening of the secondary gas jet may be smaller than the inlet opening of the glass, i.e. be between 1: 6 and 1: 1 with respect to the size of the glass inlet. In the device according to the invention, the size of the outlet opening of the secondary jet can vary from about 0.3 to 2.5 mm. At the same time, the use of a small secondary gas jet outlet requires the use of a high jet pressure while all other operating conditions remain essentially the same. Secondary gas jet pressures in the range of about 2-25 bar can be used.

In embodiments using small secondary jets, the distance between the center lines of the secondary gas jet and the glass outlets, measured in the main flow direction, may be on the order of 3-4 times the diameter of the secondary gas jet outlet, i.e. about 1-10 mm.

In the operation of the defibering center of Figure 1, air currents are provided by a secondary gas jet from orifice 36, as indicated by arrows 206, and these jet-induced currents affect the position of the glass fiber S to attract the fiber to the secondary jet as the flow interface is approached. This action has a stabilizing tendency, i.e. it seeks to ensure that the entry of the glass fiber into the secondary jet and main current interaction zone remains constant and stable, and thus the entry of glass into the stretching zone also remains constant and stable.

Examining Figure 1, it can be seen that quite large distances are provided between all the main members of the fiberization station, including the crucible, the secondary gas jet feed pipe and the main flow generating and transmitting equipment. Thanks to this increase in the distances between the members of the fiberization station, the heat transfer between the crucible and the main stream and the secondary jet generators is effectively reduced. It follows that this makes it possible to adjust the temperature of the glass. This arrangement also makes it possible to use mixtures that melt at higher temperatures or to achieve higher glass feed rates.

It is also possible to use several defibering stations in the transverse direction of the main stream.

The glass feed opening 37 used in the embodiment of Figure 1 may be a simple mouth opening or as explained in more detail below in connection with Figures 2 and 3.

Referring now to Figures 2 and 3, it can be seen that the general arrangement of the main members is analogous to that described above, although the vertical distance between the interface between the glass supply port 37 and the main stream 12A is not as large as in Figure 1.

In the embodiment of Figures 2 and 3, both sides of the crucible 200 are provided with aluminum fiber insulation (e.g., 60% Al 2 O 2) as shown at 207, thereby reducing heat loss from the crucible while protecting the jet tubes 203 from the high temperature of the crucible. In order to withstand the temperature of the molten glass, the crucible 200 is normally a platinum alloy, and the insulation just described allows other members such as the nozzle 203 to be made of less expensive metals such as stainless steel.

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When the insulation shown at 207 is present between the crucible on the one hand and the secondary gas jet on the other hand and the jet feed members, it is possible to maintain a larger temperature difference between the glass on the one hand and the gas forming the secondary gas jet on the other. In this way, even when the temperature of the secondary jet is relatively low, the insulation 207 makes it possible to keep the temperature of the glass relatively high without excessive heat loss. This arrangement facilitates operations at high production rates.

Looking at the shape of the glass feed channel shown in Figures 2 and 3, it can be seen that the glass channel has a calibration or dosing opening 37c at the bottom of the crucible and that this channel expands both above and below the calibration opening. The extension above the calibration opening is funnel-shaped, which facilitates the passage of the glass through the calibration opening to the expansion, i.e. the spare pocket, from which the glass fiber leaves. The aline expansion forms a small reserve from which the glass fiber leaves. The circumferential length of the feed opening 37 can be 2-3 times the circumferential length of the calibration opening 37c, and the entire circumference of this feed pocket is wetted by glass, which contributes to the stabilization of the glass bulge leaving the opening, especially at high temperatures. Due to this reserve pocket, the base of the glass bulge, i.e. the cone, is larger in size and thus gives a longer cone, so that the distance between the glass feeding point and the point where the fiber is formed in the cone is increased. This downward increase in the distance from the fiber birth point reduces the tendency of the fibers to accumulate in the members of the apparatus in the vicinity of the fiberization station.

Although the pocket terminating the glass feed nozzle may be circular, it is preferred to use an oval pocket extension with a long axis upstream downstream of the main stream 12A, as shown in Figure 3.

When using the glass supply arrangement described in connection with Figures 2 and 3, the calibration opening 37c forms the actual glass supply opening, i.e. its feed adjustment opening.

In the embodiment according to Figures 2 and 3, the pressure of the secondary jet may preferably be slightly higher than in the embodiments according to the above-mentioned patent publication due to the distance between the gas jet and the main flow. As a result, secondary jet pressures of 2-10 59579 bar can be used when the inlet diameter is about 2 mm, and when the inlet diameter is about 1 mm, the pressure can be 2-25 bar.

The fact that high pressures and high kinetic energies can be used in the secondary jet makes it possible to increase the amount of glass fed through the feed opening and to improve the uniformity of glass flow and the stability of the glass cones formed, which in turn improves the uniformity of the fibers produced.

In addition, the ability to use high pressures in the secondary jet and the separation of the secondary gas jet and glass inlets from the main stream are of paramount importance insofar as they allow greater distances between the secondary jet and the glass feeder centerlines. In addition, these factors also facilitate the use of glass feed nozzles that are larger in size than the diameters of the secondary jet feed orifices, e.g., 1-2 times the diameter of the secondary jet outlet nozzle when using secondary jet pressures up to 12 bar and 2-3 times Between 12 and 25 bar.

In the embodiment described above in connection with Figures 2 and 3, the width of the glass feed opening reserve pocket measured perpendicular to the flow direction of the main stream 12A may typically be 1.3 times the diameter of the secondary jet outlet and may be 2 times its width.

Using the embodiment described above in connection with Figures 2 and 3 and using as raw material glass having a composition according to Example II of the above-mentioned patent publication, glass fibers were prepared with the operating parameters and results shown in the following table: 12 59S79

Glass production 35-40 kg per day and glass feed opening

Micronar 4.0 / 5 g

Fiber diameter 5-6 microns

Main current 12A - temperature 1550 ° C

- pressure 0.2 bar - speed 450 m / s

Secondary shower - temperature 600 ° C

- pressure 7 bar - speed 560 m / s - outlet diameter 2 mm

Ratio of kinetic energies spherical jet _ r main current 12 Ά

Referring now to Figures 4, 5 and 6, there is again shown an embodiment in which the crucible 200 is connected to the pre-furnace 201. The structure 202 is adapted to direct the main stream 12A in a generally horizontal direction below the crucible.

In this case, the crucible is provided with two sets of glass feed nozzle rows 37A and 37B located at an oblique cross-position Mana as shown in Fig. 6. The secondary gas jet feed manifold is provided with branches having secondary gas jet outlets 36B adjacent to the glass inlets 37B, and is also provided with complementary secondary gas jet feed structures having jet outlets 36A connected to the glass inlets 37A, respectively. All of these feed ports 36A, 36B, 37A, and 37B are a certain distance above the upper interface of the main stream 12A. Not only does this embodiment comprise a number of fiberization centers in an oblique cross-section, it also makes it possible to obtain a vertical distance between the feed openings and the main current interface.

In certain embodiments, such as those described above, where very high fiber production capacity can be achieved, the fibers sometimes tend to cross the main stream 12A without becoming fully stretched. This results in a tendency for the fibers to prematurely solidify in parts and, as a result, for coarse fibers in the finished products. Such disadvantages can be avoided by using the embodiment according to Figure 7.

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In Fig. 7, the defibering apparatus is generally arranged in the same manner as in Figs. This slab extends below the main current and is curved so as to move away from the center line of the main current. This plate is followed by an extension 209 which, together with the plate 208, forms a gap 210 for supplying a layer of air or other suitable gas down the pipe 211.

In this embodiment, the curved surfaces of the wall members 208 and 209 provide a wall effect that causes a change in the direction of the main current, resulting in an increase in the free space between the glass feed opening and this current. This effect is similar to that obtained in the embodiment of Fig. 11 of the above-mentioned patent publication, but in addition, the effect of the wall is amplified by supplying an air flow through the slot 210. As a result, the thickness of the main stream increases in the hot zone, i.e. in the zone where the defibering takes place. This device can be used to eliminate the tendency of the fibers to cross the main stream and to prevent premature cooling of the fibers before the desired stretching has taken place. In the device according to Fig. 7, the pressure of the fan which presses air through the gap 210 can be of the order of 3 to 6 bar.

Another embodiment of the invention is shown in Figure 8. In this embodiment, a main current generator is located below the jet manifold 212, the manifold having a series of openings 36, each of which is supplied with a secondary gas jet forward and downward from the combination to form interaction zones with the main stream 12A.

According to Fig. 8, the glass is fed from a tank, i.e. a basin, into a bath 213, which is arranged so that it is filled by a feed chute 21H. The tub is bounded by walls, one of which is shown at 215, and the tub includes an overflow threshold 216. A layer of molten glass flows over and down the threshold to the secondary gas jets spraying from the openings 36. As a result of these jets and the currents produced by them, as explained in the above-mentioned patent publication, especially in connection with its figures 12, 12A, 13A and 13B, the glass flow of the layer is divided into strands 37s. Each strand is formed at one second of the secondary gas jet, and each strand penetrates the interaction zone of the secondary gas jet and the main stream, thereby providing defibering.

ΐ 4 5 95 7 9 This embodiment has proven to be advantageous in some cases, in particular in the defibering of certain extremely refractory or corrosive substances such as slags and certain other mineral formations. This type of fibrous material tends to cause excessive wear of the private feed openings, and as a result, the crucible and other basins from which these materials are fed through the feed openings need little time to be replaced with new ones, causing fiberization to be interrupted.

As in other embodiments described herein, the distance between the nearest interface of the main stream 12A of the outlet ports 36 of the secondary gas jets may be on the order of 5-10 mm. The distance between the outlet openings of the secondary gas jets and the threshold 216 at the point where the molten glass layer differs from the threshold can be of the order of 2-10 mm.

To facilitate the handling of certain types of molten, stretchable material, especially when the material tends to clog the orifices of the mouthpieces or corrode the mouthpiece material at high temperature, certain arrangements utilizing highly inert, i.e. corrosion-resistant and highly refractory materials such as chromium oxide or alumina base can be used. materials, etc. One such embodiment suitable for this case is shown in Figures 9 and 10. It uses a crucible 217 consisting of a material based on refractory oxide. It is fed with a stream of molten stretchable material, as shown at 218. One of the walls of the crucible is in the form of a dividing plate 219 with slots, which forms a separate feed chute for each material thread S.

The main power generator 220 supplies main power from the nozzle 202 to a location well below the manifold 219. A plurality of tubes 203 having outlets 36 are fed from the manifold 204 as described above in connection with the other figures, and the gas jet generator 211 supplies gas to the secondary gas jets.

As in the other embodiments described above, for example in Figs. 1, 2 and 3, the secondary gas jet outlets 36 are positioned to form interaction zones with the main stream 12A at points substantially vertically below the descending strands S of the stretchable material so that the strands interaction zones and thus defibered.

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In the embodiment of Figures 9 and 10, the notches in the manifold 219 may be located well above the main current interface, for example 50-100 mm away, and the secondary gas jet outlets 36 are preferably located 5-10 mm above the main current interface. When handling some stretch materials prepared at very high temperatures, it may be necessary to arrange cooling so that the material is fed at the optimum fiberization temperature. The distance at which the manifold plate is above the main stream may in itself be sufficient for the necessary cooling of the molten material strands S, but if desired, additional cooling can be achieved, for example by lowering the temperature of the secondary gas jets and the main stream gas. These gases can be, for example, flue gases (which can be cooled upstream of the supply point) or air or steam.

Figure 11 shows another device that can be used in the various embodiments described above in connection with Figures 1-10. The defibering station shown in Fig. 11 is analogous to that shown in Fig. 1, except that Fig. 11 also shows another gas jet. The nozzle tube 222 with the outlet opening 223 is located at a point downstream of the glass fiber S with respect to the main flow direction. One such tube 222 may be fitted at each defibering station and may be fed a gaseous medium from a manifold 224 which is fed in any suitable manner by a line 225 ·

The downstream auxiliary tubes 222 can be used especially when the free fall distance of the strands S is relatively long, and these additional gas jets serve to stabilize the strands at the moment they enter the interaction zones between the secondary jets from the openings 36 and the main stream 12A.

When a downstream auxiliary gas jet having dimensions approximately the same as the secondary jet and a pressure and velocity approximately the same are used, the secondary jet and the auxiliary gas jet both provide suction flows indicated by arrows in Fig. 11 thus more or less symmetrically distributed with respect to the strand S to maintain the thread in a sufficiently fixed position between the jets of gas and at the point where they penetrate the interaction zone.

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In all of the embodiments shown in the drawing and described above, the secondary gas jet outlet 36 is located in a position upstream of the main gas flow member. Although this is the most suitable position of the secondary gas jet outlet at each defibering station, the secondary gas jet outlet can be located at other positions relative to the glass feeder, i.e. to the wire fiber to be defibered. Thus, the outlet of the secondary gas jet can be located even downstream of the glass, i.e. the fiberizable filament feed member, with respect to the flow direction of the main stream. In this case, for the reasons explained in said patent in connection with Figures 6 and 7, the glass fiber enters the mainstream surface around and enters the secondary gas jet and the mainstream interaction zone just downstream of the secondary jet and then directs into the mainstream interior in this zone.

Claims (15)

A process for producing fibers of thermoplastic material, such as glass, according to which a main gas stream is produced and at least one secondary gas stream, whose cross-section is smaller than the main gas stream but whose kinetic energy per unit volume is greater than that of the main gas stream is directed perpendicular to the main gas stream so as to penetrate it and form a zone of interaction, and said material in an extensible state is guided from the source of the thermoplastic material to the zone of interaction, characterized in a free space separating the main gas stream from said source, along paths meeting the main gas stream in each zone where the secondary stream enters the main gas stream. Method according to claim 1, characterized in that the material jets are discharged by means of the centrifugal force and that each secondary jet is directed against the main gas stream from a point which is distant from the source of the material. Method according to Claim 1 or 2, characterized in that each secondary jet is discharged upstream of the material string in relation to the direction of movement of the main gas stream and is obliquely controlled in relation to this material string, while the angle between the center lines of the secondary jet and the main gas stream is less than about 90 °. - 85 °. Method according to any of the preceding claims, characterized in that the molten material is caused to move in the form of a layer, while the secondary jets, which are in free state and directed against the main gas stream, move in the vicinity of said material layer. The radiators generated the air stream divides the layer into strands which are brought to the zone of interaction. 5. A method according to any of the preceding claims, characterized in that the free space is enlarged by changing the direction of the main gas stream by means of an additional jet which strikes the surface of the main gas stream opposite to the surface into which the thermoplastic material and the secondary jets penetrate. Apparatus for producing fibers according to method t according to claim 1, comprising a generator (220, 202) for the main gas stream (12A) and provided with an outlet opening, a generator (203, 294, 205, 212). , 221) generating at least one secondary jet whose kinetic energy per unit volume is greater than that of the main gas stream, wherein the secondary gas jet generator comprises an outlet port (36) whose cross-section is smaller than the main gas stream outlet main stream, and controls the secondary gas stream forming a zone of interaction, a discharge source (200, 201, 214-219) for the material having a food tone, a discharge opening (37) which feeds material to the zone of interaction, characterized in that the discharge opening (37) of the material opens at a distance from the interface of the main gas stream (12A) and is so positioned that it controls at least one material strand (S) in a stretchable state to the free space so m separates the output source and the main gas stream from each other, along a path that strikes the main gas stream in an area where the secondary gas stream enters therein. Device according to claim 6, characterized in that the outlet opening (36) of the secondary gas jet is in the free space, spaced from the outlet opening (37) and that the center line of the secondary gas jet is obliquely relative to the material string (S), which is discharged by means of centrifugal force. the source of output. Device according to claim 6 or 7, characterized in that the vertical distance between the discharge port (37) of the material and the interface of the main gas stream is about 10-100 mm. Device according to any of claims 6-8, characterized in that the distance in the direction of movement of the main gas stream between the center lines of the outlet opening (37) and of the outlet opening (36) of the secondary gas jet is about 4-10 mm. Device according to any of claims 6-9, characterized in that the vertical distance between the outlet opening (36) of the secondary gas jet and the upper interface of the main gas stream is about 5-10 mm. Device according to any of claims 6-10, characterized in that it comprises a wall (208, 209) which changes the direction of the main gas stream (12A) so that it extends from the discharge port of the material, said wall being on that side. about the main current opposite the output port. Device according to any one of claims 7-11, characterized in that it comprises a tube (222) for an auxiliary beam, which is in the free space, downstream of the material strand (S) relative to the direction of movement of the main gas stream (12A). for stabilizing the string (S) as it enters the main gas stream zone for interaction. An apparatus according to claim 6 comprising several tiles