FI62812C - FREQUENCY REQUIREMENT FOR FRAME STARTING FILTER FRONT AND UTDRAGBART MATERIAL - Google Patents

Description

ral ANNOUNCEMENT

® 11 ^ UTLAGQN INGSSKRI FT 6281 2 C Patent oycnncIty '0 03 1933 ^ T ^ (51) Kv.lk.Wci.3 C 03 B 37/06 FINLAND — FINLAND (21) hMnnJhekemu · —Paunor »eknifi (78l8U0 (22 ) H »k« mUpttvt — Ameknlnpdtf O8.O6.78 ^ (13) AlkuptM — Glklghradig O8.O6.78 (41) Tulhit (external - Bllvtt offtntMg 2h 02 79 (44),. _

Pstane · och r «gistorstyr« lMn 'AntOiun utlagd oeh utl. * KrHt «n pubUcand 30.11.82 (32) (33) (31) Pyydetty atuoilcMt — Begird priorltet 23.08.77

France-France (FR) 7725691 (71) Saint-Gobain Industries, 62, Bd Victor-Hugo, 92209 Neuilly sur Seine, France-France (FR) (72) Marcel Leveeque, Saint-Gratien, Jean A. Battigelli, Rantigny,

Dominique Plantard, Rantigny, France-France (FR) (7I +) Berggren Oy Ab (5¼) Method and apparatus for making fibers from a stretchable material -Förfarande och anordning för framställning av fibrer frän ett utdrag-Bart material

The present invention relates to a method and an apparatus for producing fibers from a stretchable material, and more particularly to the stretching of thermoplastic materials, especially mineral materials such as glass and the like, which have been brought into a molten state by heating. The present invention also relates to the defibering of certain organic substances such as polystyrene, polypropylene, polycarbonates and polyamides, but the device is of particular interest in the case of stretching glass and the like thermoplastics, and this description is exemplified by the defibering of glass.

Some methods are known which use eddy currents to produce fibers by stretching molten glass.

In particular, the French patent publication 2,223,318 describes the formation of counter-rotating vortex pairs in an interaction zone obtained by conducting and infiltrating a gas jet, called a secondary jet jet. .

In the device used to carry out this method, the feed opening which directs the glass fiber towards the interaction zone thus formed is located at the limit of the main current or practically at this limit. However, it is also possible, just like yuom. in Patent No. 59576 to tpat.hak. No. 760383) is described, places a feed opening in the glass at a distance from the main current and conveys the glass fiber by gravity towards said interaction zone.

On the other hand, it has been proposed to place both glass feed openings and secondary jet outlets at a distance from the main stream boundary, with the glass strands being conveyed to the respective interaction zones by the jets themselves, subjecting them to two stretching stages, one in the secondary jet and the other in the secondary jet. This arrangement is explained in particular in Finnish Patent No. 61676 (Pa.t-Hak. No. 773788).

Furthermore, according to the latter of these applications, the formation of a stable zone in which the flow is laminar and which is located between two vortices rotating in opposite directions causes a secondary jet (i.e. a carrier jet) which carries the glass to the interaction zone formed with the main stream. The glass fiber is introduced into this laminar zone and then enters a region of vortices which vortex later join the carrier jet going downstream before the jet reaches the main stream. In this way, the first stretching step takes place with the strand drawn and exposed to the turbine pair of the carrier jet, while the second step, which is preferred but sometimes conditional, takes place in the interaction zone with the main stream after the carrier jet and the partially stretched strand enter.

In the present application, the laminar flow zone and the vortices of the carrier jet belonging to each defibering center are obtained by disturbing the jet so that it changes direction. This interference is achieved by placing a deflector member, i.e. a control member, in the path of the jet leaving each defibering center, which changes this fiber path, whereby the change in the direction of the jet contributes to the stability and regularity of the operation, notwithstanding its point, 6281 2 3

Where the glass is fed into the carrier jet, and the distance between the main stream.

It is an object of the present invention to achieve good stability of a strand of glass or other stretchable material when stretching a strand of material by means of gas jets in at least one stretching step without the resulting gas flow being disturbed by the carrier jet by a mechanical member. The method according to the invention offers some rather specific and interesting advantages and is characterized by the development of a series of gas jet pairs which are laterally spaced apart and each comprise two jets with substantially equal kinetic energy per unit volume, the two jets being practically controlled viewed in the same plane in converging directions, the jets, when colliding with each other, forming a combined flow; the lateral propagation of each combined flow is limited by the impact on adjacent flows so that at least two vortices rotating in opposite directions are formed in each of them; the filament of material in the stretchable state is introduced towards each pair of jets, each filament being introduced into the induced gases from outside the angle between the two jets and then introduced into the combined flow in which it is stretched; and optionally generating a main gas flow at an angle to the series of combined flows.

Each strand of stretchable material is directed towards the pair of jets at a position located in the plane containing the axes of the respective pair of jets. In this way, the filament of material directed towards each pair of jets is directed to a zone of laminar flow bounded by vortices rotating in opposite directions.

Another feature of the invention is that two jets of approximately the same size are used for each defibering center. The kinetic energies per unit volume of the two wedding showers are preferably substantially equal.

Although this double jet system can be stretched in only one step, in the vortices developed in the co-current of the two jets, the fibers are preferably produced by a two-stage process in which the co-current of the two jets is also used as a means of introducing a glass filament into the interaction zone. flow, which method produces finer fibers thanks to this additional stretching.

In each fiberization center, the vortices generated in the jet flow in each pair of jets converge downstream of the laminar flow zone and the combined flow advances to the main stream, penetrates it and thus forms an interaction zone, which also comprises a vortex pair and its properties are described in French Pat.

Each glass fiber is thus subjected to a primary stretch in the kaa stream and, more specifically, between the two vortices generated by each pair of carrier jets, and the partially stretched fiber is then subjected to a second stretch in the interaction zone formed by the combined flow of carrier jets. This method of stretching into a single fiber, performed in two steps, makes it possible to obtain long fibers between them without breaking.

The device for applying the method according to the invention comprises at least one gas jet outflow device provided with outflow openings, a stretchable material supply source provided with at least one supply opening, and optionally a main gas flow generator, the device characterized in that the gas jet outflow device comprises a plurality of orifice pairs. are laterally spaced apart, with the two openings of each pair having converging axes located in substantially the same plane, and that the material feed opening for the stretchable material is located outside the angle between the axes of the two jet outlet openings relative to the gas jet pair.

Advantages and embodiments of the invention will now be described in more detail with reference to the accompanying drawing, in which: Figure 1 is a schematic elevational view of the main parts of the defibering and fiber receiving apparatus according to the invention; Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 3, Fig. 5 6281 Fig. 5 is a sectional view of the main parts of the defibering device and shows in particular some dimensions to be taken into account in the preferred embodiment of the invention. Fig. 6 is a detailed sectional view showing the distances between the outlets of neighboring jets, Fig. 7 is a cross-sectional view of the stretchable material feed nipple and the front some of the dimensions to be taken into account.

Referring first to Figure 1, there is a schematically shown main current generator, such as a burner, comprising a tube 9 »from which the main current 10 originates in an approximately horizontal direction. However, this may be directed in a direction other than horizontal.

The collector 13, which is connected to the jet distribution box 11 by a connecting pipe 12, supplies a pressurized gas, for example compressed air, to it.

Figures 2 and 3 also show that the jet junction box has outlet pairs, 14, 15 for transmitting jets, and these adjacent pairs of apertures are indicated by reference numerals 14a, 15a; 14b, 15b; l ^ c, 15c; l ^ d, 15d; l4e, 15e. The showers leaving these pairs of openings are marked with corresponding letters. Figure 2 is a perspective view of three pairs of jets, while Figures 1 and 3 show only one pair of jets a, a. There is one defibering center for each pair of showers.

In each defibering center, the jets of a pair of jets, for example jets a, a, collide with each other in their common plane and form a combined flow, denoted by the reference letter A in Fig. 1, in which the strand of stretchable material is subjected to primary stretching. The combined flow, i.e., the combined carrier jet, advances downward and penetrates into the main stream 10, forming an interaction zone with it that is used for the second stretching step.

In these figures, the source of the glass feed is schematically shown at 16. It comprises a pull plate 17 with a series of glass feed nipples 18 spaced apart, each of which has a feed opening 18a, and an upstream dosing opening 19 at the upstream end. the glass strands S flow downwards. Each defibering center comprises one blank and one thread. The fibers formed from a series of defibering centers distributed transversely to the width of the main stream 10 are then deposited on a perforated conveyor, i.e. a belt 20, as a fiber layer B. The distribution of fibers 6 6281 2 to this conveyor occurs within a chamber bounded by, for example, a wall 21 by suction chambers 22. preferably located below the conveyor 20 and connected by ducts 23 to one or more suction fans schematically shown at 24.

The defibering with the device described above will be explained and analyzed in more detail in connection with Figures 2, 3 and 4.

As already mentioned above, the actual process in each discharge center is preferably related to the effect of the jets of the neighboring centers. Figure 2 shows the stretching process completely in the part of the defibering center corresponding to jets b, b, and only in part to the defibering centers corresponding to jets a, a and c, c. Figure 3 shows on a larger scale what happens in a fiberization center comprising jets a, a. In order to analyze this process, i.e. operation, it should first be recalled that each gas jet induces the movement of the surrounding air, starting from its outlet. As a result, each shower a comprises a central part, i.e. a core j, surrounded by a gas jacket i containing induced air. This sheath expands rapidly as the jet flow progresses, while the heart remains a relatively short, conical central portion. The velocity of the gases forming the core of the jet is equal to the velocity of the jet as it leaves its outlet, while the velocity of the gases in the jacket decreases as the flow progresses. The arrows marked in Figures 2 and 3 indicate the flow of the jets, but also the induction of air by the main current.

When two jets having approximately the same kinetic energy per unit volume and preferably also approximately the same dimensions are used, and the center lines of the two jets are in the same plane and converge, preferably at an acute angle, the combined flow propagates laterally downstream of the jet collision area , i.e., it propagates in directions perpendicular to the plane of the center lines of the jets. According to the present invention, the jet pairs, i.e. the planes containing the center lines of the jets, are so close to each other that in each fiberization center the propagation of one pair towards the sides is disturbed, i.e. limited by its collision with its adjacent jet pairs during propagation. This collision of adjacent converged currents develops two small vortex heads for each flow, with the peaks of the vortices belonging to the same pair being spaced apart on either side of the plane of the center lines of the jets.

Figures 2, 3 and 4 schematically show the upper and lower vortex pairs. The vortices of the upper pair, denoted tu, tu, consist of currents rotating towards each other at the top and in the opposite direction at the bottom, as indicated by the direction of the arrows in Fig. 4. Instead, the vortices of the subordinate pair, denoted by tl, tl, rotate in opposite directions.

Between these two pairs of vortices, in the region of the jet mutual collision, a laminar flow zone L associated with these vortices is formed, in the region of which the air absorption is very strong, and it is to this zone L that the glass fiber S is fed to the upper vortices. This thread is formed by a glass blank, i.e. a cone G, the position of which is displaced with respect to the jet transmitting device. Since the glass blank G is in a stretchable or molten state at the outlet end of the feed nipple, the stretchable glass thread S deviates from the original position of the blank in the laminar flow zone L due to the induced strong air flow, and this phenomenon ensures the passage of stretchable material to the laminar zone. As a result, even if the extension of the glass feed nipple 18 with respect to the jet pair is slightly deficient, the flow of induced air automatically compensates for this deficiency and directs the glass fiber to its correct position Thus, it is understood that at least one pair of vortices is formed in each defibering center. flank the laminar flow zone and that the material is introduced in a stretchable state to an area close to that zone, the induced airflows, which, as described above, automatically compensate for possible extension errors, automatically entrain the material thread into that zone, leading to stabilization of the stretchable material supply to the system. This stabilization is achieved even if the glass feed nipples are at a considerable distance from the jet outlets, a distance which is desirable to facilitate proper temperature control and maintenance at both the feed nipples and the jet outlets.

On the downstream side of the laminar zone L, the vortex pair tu, tu, but also the vortex pair t1, t1 tends to merge together, and as the flow proceeds downstream, they tend to lose their identity, as shown in Fig. 2 in the section showing the jets c, c two pairs of vortices born. The combined flow of each pair of jets then propagates downwards and penetrates into the main stream 10, as shown for the flow from the pair of jets b, b. The combined jet then forms with it the interaction zone completely analyzed in the above-mentioned patent publication and comprising complementary vortex pair T.

It should be noted that each plane containing the centerlines of the same pair of jets preferably intersects the main stream in a straight line that is substantially parallel to the direction of travel of the main stream.

Each glass fiber S is thus subjected to primary stretching in the flow of the merged jets, between the laminar flow zone, i.e. the glass feed point and the point where the jet penetrates into the main stream, after which the partially stretched filament is subjected to further stretching in said flow interaction zone. It can be seen from the figures that these two stretching steps take place without breaking the glass fiber, so that each fiber forms a single fiber.

In order to carry out the process described above for each defibering center, in particular the formation of vortex pairs, each of which borders the flow zone of the laminar, a pair of jets is used, both jets preferably having equal kinetic energy per unit volume. Also, the cross-sections of these jets should preferably have the same surface area, although it is possible to allow a small difference between these areas, especially if the kinetic energies per unit volume of the two jets are practically the same. In addition, the cross-sections of the two showers of one defibering center are preferably in the shape of a sauna.

Furthermore, it is not necessary that the cross-sectional dimensions of the jet be exactly the same in the direction of the plane containing the centerlines of the jets and in a direction perpendicular thereto, and moreover the two dimensions need not be equal to the corresponding dimensions of another jet of the same pair. However, it is desirable and advantageous that these dimensions are the same or very close to each other in one shower, but also in the two showers of the defibering center. And further, it is desirable that the jets of adjacent jet pairs be substantially the same size so that the vortex pairs flanking the zones of laminar flow can become uniform when each combined flow impinges on the adjacent flow as it propagates laterally. This perfect similarity of the jets of adjacent defibering centers makes it possible to achieve uniform defibering conditions in the different interaction zones created by the intrusion of the jets into the main stream.

The flow generated from each pair of jets can be used to make the fibers, without resorting to the main stream. In most cases, however, and especially for the production of relatively fine fibers, it is preferable to use not only primary stretching in the flow of one pair of jets, but also complementary stretching, which occurs when this flow penetrates the interaction zone generated inside the main stream.

For this intrusion to occur, the combined flow per unit volume of kinetic energy must be greater than the main flow when it reaches this.

It should also be noted that these paired jets must have certain specific properties in order to form a zone of flow in the laminar into which the glass fiber can be fed without breaking. In fact, it is important that their centerlines are located in substantially the same plane and meet each other therein, preferably at a sharp angle, the value of which is preferably within the limits set forth below. Other parameters specified in Figures 5, 6 and 7 must also be considered.

Fig. 5 is a sectional view, similar to Fig. 3, of the three main members of the apparatus used to form the fiberization center, namely, the main current generator, the jet transmitter, and the source of material to be stretched. It is marked, as in Figures 6 and 7, by symbols denoting the various parameters, such as dimensions and angles, to which the following tables refer, in which tables the most suitable ranges of dimensions and angles and their preferred values are given.

10 6281 2

Table I

Traction plate and stretch material feed nipples.

Symbol Primary value (mm) Range dT 2 1-5 1T 1 1 - ^ 1R 5 0-10 dR 2 1-5 dR 5 1-10

The term "stretchable material feed port" as used in this specification is to be understood in a very broad sense. In fact, it can mean either a separate opening connected to a single pair of jets or a series of openings, each located at the end of a feed nipple, for example, or a feed slot common to several consumption centers, as described in French Patent 2,223,318. When the orifice row is replaced by a slot associated with the jet pair row and transverse to the main stream, the stretchable material exiting the slot is divided into a series of cones and strands by the jet pairs and their air currents induced at different fiberization centers. The induced currents take each formed glass fiber with it to the corresponding laminar flow zone. In this case, the center line of each glass cone is automatically located in the plane containing the center lines of the jets of the corresponding shower pair.

Table II Output of shower pairs

Symbol Primary value (mm, degrees) Range dJX 2 0.5-4 dJ2 2 0.5-4 3 1 -LjS 5 2-10 oJJ 45 10 - 90 aJB 45 20 - 90 11 62812

As for the jet pair transmitting device, it should be noted that this may also consist of two superimposed jet distribution boxes, each with one row of openings in the front wall, arranged so that this group of two distribution boxes forms outlet pairs having the characteristics described above.

Table III

Main power

Symbol Default value (mm) Variation Read section 10 5 - 20

Table IV

Mutual positions of different bodies

Symbol Default value (mm) Range ZJF 8 1 - 15 ZJp 17 12 - 30 XRT 0 -20- + 5 * “

The negative values of the symbol XBJ correspond to the case shown in Fig. 3, where the intersection of the paths of the two jets leaving each defibering center, i.e. the center lines, is located downstream of the main stream from which the main stream originates.

The number of defibering centers can be as high as 150, but in a normal defibering plant for glass or similar thermoplastic material, a valid draw plate has, for example, 70 feed nipples.

It should also be noted that the operating conditions of the system of the present invention vary depending on many factors, for example, the properties of the material to be defibered.

As mentioned above, the present invention can be applied to a wide variety of stretchable materials. However, in the case of stretching glass and other inorganic thermoplastics, the temperature of the drawing plate or feed source varies depending on the material to be fiberized, and generally in the temperature range of about 1400 to about 1800 ° C. In the case of conventional glass alloys, the temperature of the drawing plate is about 1480 ° C.

The unit flow rate can range from 20 to 150 kg per opening in 24 hours, and typical values are between 40 and 60 kg per hole in 24 hours.

Also important are some values for the jet and mainstream, which are given in the following tables using the following symbols: P = weight T = temperature V = speed p = specific gravity

Table V Output of each shower

Symbol Primary value Range

Pj baria 2.5 1-15

Tj (° C) 20 0 - 1500

Vj (m / sec) 330 330 - 900

PjV2j (baria) 2.1 0.8 - 40

Table VI

Main power

Symbol Default value Range PB (mbar) 95 30 - 250 TB (° C) 1450 1350 - 1800

Vg (m / sec) 320 200 - 550 ρΒγ2Β (baria) 0.2. 0.06 - 0.5 6281 2 13

When stretching is performed in two stages using both a double jet system and a main stream, the width and preferably the cross-section of the jets should be smaller than the main stream, and this flow penetrates the main stream to form an interaction zone where the second stage of stretching takes place. For this purpose, the combined flow of the jets must have a higher kinetic energy per unit volume than the main current in their interaction zone. When the jet stream reaches the main stream, its kinetic energy per unit volume can be, for example, about 10 times as high as the main stream, i.e.: pjv2j pbv2b are approximately the same size and that their speed and kinetic energy are also the same. However, a certain difference can be allowed for at least some parameters.

The invention offers numerous advantages, especially in the defibering of various materials and in particular mineral thermoplastic mixtures such as glass and the like.

Among the important advantages and features of the invention are the following in particular:

In a preferred embodiment of the invention, in which the pair of jets belonging to each defibering center also has the function of introducing the stretchable material into the interaction zone formed by the combined flow into the main stream, the use of such a pair of jets provides stability in In addition, this supply stability is achieved even if there is a considerable distance between the main members of each defibering center, namely the source of the material to be stretched, the jet transmitter and the main current generator. Such a distance is very important for a number of reasons, especially since it is desirable to avoid excessive heat transfer between the various members of the defibering system; in particular, it makes it possible to achieve and stop the desired temperature conditions in each organ, which precise temperature control is desirable in order to achieve regular fiberization and thus also fibers of good quality.

With respect to these temperatures, it should also be noted that it is preferable to use a gas such as compressed air at a temperature close to ambient temperature because the source of the material to be stretched, such as glass, and the main current generator are both kept at a relatively high temperature. These temperature differences can be effectively observed in the system according to the invention thanks to this possibility of placing the different members of the system quite far apart.

Furthermore, in the apparatus of the present invention, the above advantages can be achieved without having to place any mechanical member along the path of a private jet or a combined pair of jets flowing to each defibering center, and even without having to precisely adjust its position. In fact, it is remembered that on the one hand the flow propagation to the sides is due to the jets of each jet pair colliding with each other and on the other hand this spread is limited, i.e. disturbed by adjusting the distance of adjacent jet pairs. This particular arrangement makes it possible to limit the lateral propagation of the combined jets and thus the development of vortex pairs flanking the laminar flow zones without placing any mechanical member in the jet passageways and thus without having to take into account the problems of wear, thermal damage or precision for use. This extremely advantageous possibility of using minimally mechanical structures in the vicinity of the supply of stretchable material further reduces the risks of the fibrous material adhering to and accumulating in them.

Claims (17)

A method of producing fibers starting from a drawable material, in particular a thermoplastic mineral material, wherein material strands are extracted by means of gas jets in at least one drawing step, characterized in that a number of pairwise gas jets are formed which are spaced laterally from each other and by each of which comprises two beams having substantially the same kinetic energy per unit volume, these two beams being conducted in substantially the same path in converging directions, the beams having collided to form a combined flow, limiting lateral propagation of the combined flow by impingement with adjacent flows, so that in each of them two rotating swirls are formed in opposite directions, one extensible state existing material strand is moved in the direction of each pair of jets, each strand being inserted into the induced gases outside the winkein. between two beams and then inserted into the combined flow, in which it is drawn, and optionally a main gas stream is generated at an angle to the series of combined flows. Method according to claim 1, characterized in that in each pair of gas jets two jets of equal cross-section and of the same shape are generated. Method according to Claim 1 or 2, characterized in that each string of pullable material is brought against the pair of rays from a place which is always located in a pile containing the shafts of the respective jets pair. Process according to any one of claims 1-3> characterized in that the material strand directed against each pair of strands is guided into a zone of laminar flow, which is limited by rotating swirls in opposite directions. 5. A method according to any one of claims 1-4, characterized in that each gas jet has a kinetic energy per unit volume of about 0.8-40 bar. Process according to any of the preceding claims, characterized in that the gas jet has a pressure of 1-15 bar. Method according to any of the preceding claims, characterized in that the two jets of each jetting pair are produced in directions which mutually form an angle of between 10 ° and 90 °. Method according to any of the preceding claims, characterized in that in the direction of cutting of the combined flow, a main gas stream is generated having a cross-section greater than but kinetic energy per unit volume less than that of any combined flow, and said flows are caused to enter the main stream. for generating zones of interaction therein, each material strand being inserted into a zone of interaction in the main stream, subjected to further drawing. 9. A process according to claim 8, characterized in that the main gas stream has a kinetic energy per unit volume of 0.06-0.5 bar. 10. A method according to claim 8 or 9, characterized in that the main gas stream has a pressure of 30-250 millibars. Apparatus for producing fibers of a drawable material by a method according to claims 1-10, which means comprises at least one emission device for gas jets provided with discharge openings, a feed device for the drawable material which is provided with at least one feedstock. orifice, and optionally with a generator for a main gas stream, characterized in that the emission device for gas jets comprises a plurality of pairwise outlet openings (14-15; 14a-15a; 14b-15b; 14c-15c) which are located at lateral distances, wherein the two openings in each pair have converging axes which are located in substantially the same direction, and that the feed opening (18a) of the drawable material is disposed relative to the pair of gas jets between the axes of these two jets. outflow openings (l4a-15a). Device according to claim 11, characterized in that the feed opening for the pullable material is located in a pile which contains the shafts for the discharge openings for said pair of beams. Device according to claim 11 or 12, characterized in that the discharge openings for a pair of beams have equal Large cross sections. Device according to any of claims 11-13, characterized in that the generator (8) for the main gas stream (10) is located at a distance from the outflow opening or the outlet openings for the pairs of gas jets, the shaft for the main gas stream.