FI59782C - FOER REFRIGERATION FOR FOAM FRAMSTAELLNING AV FIBER AV THERMOPLASTIC MATERIAL - Google Patents

Description

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Patent- och regiaterttyrelMn '7 Anattkan uthgd och utUkrtfttn publk «r» d 30.06.01 (32) (33) (31) Pyydetty «tuolkoii» —begird prloritet 21.02.75

France-France (FR) 7505512- (71) Saint-Gobain Industries, 62, Bd. Victor Hugo, 92209 Neuilly sur Seine, France-France (FR) (72) Marcel Levecque, Saint-Gratien, Jean Battigelli, Rantigny, Dominique Plantard, Rantigny, France-France (FR) (7 * 0 Berggren Oy Ab (5 * 0 Method and apparatus for making fibers from thermoplastic materials -Förfarande och anordning för framställning av fibrer av thermoplastiska material

The invention relates to a method and apparatus for producing fibers from a thermoplastic material, such as glass, which provides a main gas flow flowing along a surface and bounding one side of the surface, directing at least one secondary gas jet with a smaller cross-section but greater kinetic energy per unit volume than the main gas stream to cause this secondary gas jet to penetrate the main gas stream to form an interaction zone, and the thermoplastic material is introduced into the interaction zone in a stretchable state. Such a method is the subject of Finnish patent FI-57 2 * 17.

The object of the invention is to improve the method so as to achieve the very advantageous technical effects described below.

The method according to the invention for producing fibers as described above is mainly characterized in that an additional gas jet is brought into contact with the main gas stream and the secondary jet stream and that the additional gas jet is introduced into the main gas stream downstream of the thermoplastic feed ports.

2,59782

According to one feature of the invention, the position and temperature of the interaction zone are controlled by adjusting the position and temperature of the secondary jet, and the current generated by the interaction is influenced by

According to another, particularly advantageous feature of the invention, the stream resulting from the interaction of the gas stream and the carrier gas jet is conducted as it progresses into contact with the second gas jet.

According to a further feature of the invention, this additional gas jet comes into contact with the interaction current downstream of the glass outlet according to the direction of flow, namely at a point in the immediate vicinity of the molten glass plate.

The apparatus for carrying out the method according to the invention comprises, as is known, a main gas stream generator with an outlet, at least one secondary gas jet generator having a gas jet kinetic energy per unit volume greater than the main gas stream, this gas jet generator comprising one or more outlets with a smaller cross-section , and directing the secondary jet transversely to the main gas stream to form an interaction zone, the apparatus further comprising a thermoplastic material supply source having at least one feed port adapted to direct the substance in the drawable state into the zone where the secondary gas jet enters the main gas stream; downstream of the main gas, and this device is mainly characterized in that it comprises a member with an outlet for directing an additional gas jet from the main gas flow, and towards the flow from the secondary gas jet, the outlet of the additional gas jet being located downstream of the inlet of the substance with respect to the flow of the main gas stream.

The patent referred to above utilizes a surface which forms the boundary of the interaction current, downstream of the melt entry point, which surface may be inclined to change the direction of the co-current.

59782 3

When such a downstream plate is used, the fibers tend to adhere to the plate, and even more so when the plate is at an angle to change the direction of the current.

It is an object of the present invention to reduce the tendency of the fibers to adhere to and accumulate in the downstream plate. To achieve this result, according to the invention, an additional gas stream, for example an air stream, is brought into contact with the main stream and the secondary jet interaction zone at the upstream edge of the downstream plate and at a point immediately downstream of the molten glass inlet. Such an supply of air to the upstream edge of the plate forms a layer of gas on the surface of the plate which is exposed to the current, which is liable to prevent the glass from sticking and accumulating on the surface of the plate.

In devices comprising a plurality of defibering stations grouped transversely to the gas stream, each comprising both a secondary jet penetrating the gas stream and a molten glass inlet, the arrangement for supplying additional gas may comprise either a series of separate jets, each with its own defibering station . In both cases, the supply of additional air is capable of developing the downstream slab of the air curtain, i.e. the layer, on the surface exposed to the current, and also of promoting the penetration of the glass fiber into the deeper interaction zone.

Some embodiments of the invention are set forth below by way of illustration. This description refers to the accompanying drawing, in which: “59782

Fig. 1 is an elevational view, partly in vertical section, showing a glass feeder, a gas flow and secondary jet generating apparatus, and an auxiliary air jet feeder; Fig. 2 is a plan view in section taken along line 2-2 of Fig. 1; Fig. 3 is an enlarged vertical sectional view of a crucible, i.e. a wire drawing device, and a plate integral therewith; this sectional view, taken along line 3 ~ 3 of Fig. 4, also shows the mutual position of the secondary jet and the auxiliary air supply devices; Fig. 4 is a plan view showing a section along line 4-4 of Fig. 3 below some parts of Fig. 3; Fig. 5 is a schematic view of some of the parts shown in Fig. 3 and shows in particular the defibering effect obtained by using the main stream and the secondary jet and in addition the effect of the additional air; Fig. 6 is a perspective view of certain gas supply and distribution devices used to generate secondary jets; Fig. 7 is a horizontal sectional view of some parts of the defibering stations, the central part omitted, and showing the location of some of the members forming the multi-station defibering device; Fig. 8 is a perspective view of an apparatus used to secure certain gas supply pipes for secondary showers; Figures 9 and 10 show a modified form of the auxiliary air supply device, Figure 9 being a section along the line 9 ~ 9 in Figure 10 and Figure 10 being a section along the line 10-10 of Figure 9; Figures 11 and 12 are partial views similar to Figure 3, but showing other embodiments of the auxiliary air supply device; Figures 13 and 14 show still other embodiments of means for forming the defibering stations according to the invention, Figure 13 being generally similar to Figure 1 and Figure 14 being a partial plan view showing some of the members of Figure 13.

The arrangement generally comprises (see in particular Figures 1-4) a fiberizing crucible 200 with a pre-furnace 201 for feeding the glass, taking into account that instead of feeding from the pre-furnace, an electrically heated crucible can be used to melt and feed the glass.

The crucible is provided with a series of glass outlets 37 for supplying glass to the interaction zone 5 59782 between the main stream and the secondary or carrier jets. Each secondary jet is associated with its own glass inlet so as to form a corresponding number of fiberizing stations. The main current is indicated by arrow 12A (Fig. 5) and the secondary or carrier jets come from the supply pipes through the holes 36. These supply pipes and holes are explained in detail below.

The main current is conducted up to line 202. The power is generated by burning some fuel in the combustion chamber 203 (Figure 1), to which a mixture of gas and air can be fed up to line 204.

The burner 205, to which the gas is supplied and, without the mixture down the line 206, supplies the gas which is led through the supply openings 36 (Fig. 5) down to the above-mentioned pipes. The arrangement of these members forming each defibering station is shown in more detail in Figures 3 and As shown in the figures, the nozzle tubes 207 fed from the burner 205 are inserted somewhat into the holes 36a and the gas jets are sprayed transversely into the gas stream 12A. As can be seen from the embodiments of Figures 1-3, the holes 36a are made in a wall, i.e. a plate 208, which is in contact with the interface of the stream 12A and is preferably integral with the crucible 200.

Each defibrillation station formed in the manner described above generally operates as described in the aforementioned patent publication, and parameters, including gas flow and secondary jet kinetic energy in the operating zone and flow and jet temperatures and velocities and glass temperature, glass and jet outlet dimensions, et al., all may correspond to the parameters described in said patent publication.

One of the improvements provided by the present invention relates to a "downstream" wall, i.e. a slab member, with which the embodiments described in the above-referenced patent publication are provided. This slab is called a "downstream" slab because it is located downstream of the defibering station relative to the direction of current 12A, i. on the downstream side of the glass feed opening 37, which in turn is located downstream of the shower opening 36. The downstream plate is shown in particular in Figures 1, 3 and 5, where it is indicated by reference numeral 209. As can be seen in Figure 1, the downstream plate is fixed by adjustable brackets 210 so that the position and inclination of the plate can be adjusted. Tile 6 59782

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209 is thus set so that its inclination changes the direction of the gas flow as it passes the glass inlet.

The downstream plate (Figures 3 and 5) has a duct 211 provided with a connection 212, by means of which a cooling medium, for example water, can be circulated through the duct 211. This recycling thus causes the downstream plate to cool.

As mentioned above, the use of a wall, i.e. a slab, on the downstream side of the fiberizing stations tends to bring about contact between the fibers and the slab, which results in a layer of glass tending to accumulate on the surface of the slab. Thanks to the improvement according to the invention, this tendency is considerably reduced due to the special conditions under which the air is supplied, preferably as a flowing layer along the lower surface of the downstream slab or around the front edge of the slab, i.e. upstream. The air or gas used for this purpose is called the "additional gas", and the jet formed by it is called the "additional shower".

In the embodiment of Figs. The plate 209 has a duct 21¾ provided with connections 215 for the supply of additional gas, for example air. A series of supply holes 216 communicate with the manifold 21¾ and supply air in the direction of the leading edge of the downstream plate, thereby supplying air to pass through the adjacent gap in the crucible. To close the space between the crucible and the downstream plate and thus ensure that additional gas cannot escape and is guided through the slot at the front edge of the plate, a sheet metal plate 217 is attached to the body 218, the lower edge of which is bent near the bottom wall of the crucible. very well with heat insulating material 219 such as aluminum fibers. It may be advantageous to make this cover from stainless steel with some flexibility. Thanks to this arrangement and the cover 217, the downstream plate can be fitted as described above while still in contact with the cover 217.

The operation of the slurry jet is shown in Fig. 5, where the flow lines show, in addition to the stream 12A and the secondary jet from the nozzle 207, an additional jet fed from the duct 21 * 1 through the holes 216 towards the front edge of the slab. at the interface, forming a current, i.e. a medium layer, at the level of the lower surface of the plate 209. The apparatus comprises a number of fiberization stations according to Figure 5 spaced some distance transversely to the current. The auxiliary gas passage 216 is adapted to extend with each secondary jet outlet 36 and associated glass inlet 37. When there is a certain number of additional gas passages, the additional gas from the multiple passages tends to coalesce and thus form a more or less continuous gas curtain as it passes through the gap and flows down to the lower surface of the downstream plate at the current interface. As a result, the fibers that are formed are effectively prevented from coming into contact with the surface of the downstream slab.

It should also be noted that the presence of the gas passage 214 and the passage of additional gas upstream surfaces contribute to the cooling of the slab, so that the action of the additional gas in the passage 211 keeps the slab at a relatively low temperature, which also prevents the glass from sticking to the slab.

In a plant where a large number of defibering stations are distributed in the transverse direction of the stream, for example about 80 stations, the upstream plate should preferably be divided into sections. As shown in Figs. Dividing the slab in this way facilitates efficient and accurate recirculation of the cooling water and ensures a precise distribution of the additional air supply, which helps to maintain operating conditions within tight tolerances.

With respect to the installation of the secondary jets shown in Figures 1-8, it should be underlined that the upstream plate 208, i.e. the base, is preferably the same piece as the crucible 200. It should preferably be a platinum alloy, as glass compositions suitable for the manufacture of fibers are used herein, and in addition to ensure uniformity of fiber formation at each of these multiple positions; it is important to precisely match the secondary jet outlets 36 and the glass inlets 8 59782 37 to the extension in the direction of the gas flow. In one of the embodiments described in the aforementioned patent, this precise extension in the flow direction of the secondary jet and the defibered glass is achieved automatically by using a narrow gap for the glass inlet rather than a series of glass feed openings arranged separately, as already mentioned above. With the arrangement according to Figures 1-8, it is also possible to achieve an accurate extension of the secondary jets with the glass strands, but in this case the accuracy of the extension is achieved despite the use of separate feed openings for the glass. This accuracy is achieved by making an upstream wall or plate 208 and a crucible 200 of the same piece. Since the holes 36a of the secondary jets and the glass feed openings are both made in the same piece, the accuracy of the extension is achieved and maintained even when the thermal expansion or contraction conditions of different parts of the piece vary.

The accuracy of the extension is further facilitated by some other arrangements included in the embodiment of Figures 1-8. Figures 2j 3, 4, 7 and 8 show that each secondary jet leaves a nozzle tube 207 which inserts a hole 36a and is slightly smaller in diameter than the hole. The shower tubes 207 are divided into groups; the drawing shows four such groups and each group is attached to a media manifold 220 connected to a supply tube 221. By dividing the total number of nozzles 207 into groups and securing each group separately, the manifold 220 supporting and feeding each group can more easily afford thermal expansion and contraction than if the nozzles would be attached to a single bracket for the entire set of defibering stations. In addition, the use of spray tubes 207 which insert each individual hole 36a and the use of tubes slightly smaller in diameter than the diameter of the holes provide an additional risk of expansion and contraction. The grouping and fitting of the nozzles as described above to reserve the expansion and contraction margin is all the more important because, as can be appreciated, the crucible 200 and the upstream plate 208 are platinum alloy and the nozzles and auxiliaries are less expensive metal such as stainless steel. have different high coefficients of thermal expansion.

As best seen in Figure 8, each array of nozzle tubes 207, together with the manifold to which it is attached and the associated feed tube 221, form a combination resembling a rake, and this combination is adapted to be attached to the lower end of the feed tube 221. As shown in Figs. It is performed by means of a flue gas diluent 225 (see also Figure 6) fitted between the combustion chamber 205 and the mounting flanges 222 of the supply pipes 221 of the nozzle groups. This flue gas diluent, which serves to reduce the temperature of the flue gases from the burner 205 to match the durability of the jet pipes, comprises air supply pipes 224 connected to pipes 225 · There are a plurality of these supply pipes 224 spaced along the length of the flue gas diluter. one for each group of secondary jet tubes. In this way, the jet tubes receive the products of the combustion chamber 205 diluted with the air supplied to the tubes 224.

As shown in Figures 2, 4 and 7, an additional secondary jet outlet hole 36 and an additional secondary tube 207 are arranged outside each end of the glass feed hole row. This arrangement is consistent with that described in the above-referenced patent publication and ensures uniform defibering operation at the glass feed opening level. at opposite ends of the series. In addition to this arrangement, according to the installations described in said patent publication, a similar arrangement is used for additional gas supply ducts. In other words, as shown in Figs.

A modified embodiment of the downstream plate and the additional jet supply is shown in Figures 1, 9 and 10. Here, the downstream plate, indicated at 227, is provided with a coolant recirculation line 228 connected to the connections 229 and an air supply line 230 with a supply means 231. Private ducts2 additional air from the line 230, is connected to the bottom of the groove 233, the edge of which is directed towards the front edge of the downstream plate and is located immediately above it. It will be readily appreciated that this structure is intended to be attached to the fiberization stations in the same general manner as described above in connection with Figure 1. The downstream plate of Figures 10, 59782 1, 9 and 10 is thus intended to be positioned according to a device which closes the space between the downstream plate and the crucible analogous to that indicated by 217 and 219 in Figures 3j and 5 · A groove such as 233 may be used to promote additional gas distribution along the leading edge of the slab and thus to promote the formation of an additional gas layer on the surface of the slab that is exposed to the interaction current.

Figure 11 shows another modified embodiment of the downstream plate and the additional gas supply. As can be seen, the cross-sectional shape of the bottom of the crucible 200 is slightly modified, and the shape of the downstream plate 234 is likewise modified to fit the bottom of the crucible, as will be explained below. The plate 234 has a channel 235 for refrigerant to the connection 236, and the additional gas supply line 237 with the connection 238 opens into ducts 239 which communicate with a narrow chamber in the form of a gap, i.e. a channel, formed between the front edge of the plate 234 and the bottom of the crucible. Adaptation devices are arranged between the plate and the crucible to ensure the flow of additional gas in the desired direction and from the slit to the front edge of the plate.

Figure 12 shows another embodiment of a downstream slab. In this form, the crucible 200 is integral with the upstream plate 208 provided with corresponding holes 36a in the spray tubes 207. Here, the structure of the downstream plate 209 is substantially the same as that described above in connection with Figures 1-8, but the system for adjusting the space between the plate and the crucible is different. For example, the lower portion of the downstream slab is provided with a metal strip 240 that extends the entire length of the slab 209 and, together with the top of the slab, defines an elongate gap for additional gas to flow into the main stream. This combination is insulated against the heat of the crucible by an insulating layer extending along the wall 240 and shown at 241. Such an insulator, as well as the insulator 219 described above, is advantageous in that it reduces heat loss with respect to the crucible.

In all of the embodiments described above, whenever spray tubes 207 are used that insert into holes integrated with the crucible, it is desirable to provide thermal insulation between the tubes and the holes. This insulation can be obtained by covering the pipes with thermal insulation such as aluminum. Such insulation both limits heat loss from the crucible and further protects the metal of the nozzles.

n 59782

All the adaptations described above also apply to the plant of the general type shown in Figure 1, in which the crucible is mounted under the glass front feed tank 201; the crucible is separated from the glass supply structure by a ceramic member 242 fitted with a coolant pipe (Figures 1 and 2). Advantageously, fibrous insulation material 244, as shown against the lower portions of the pre-tank, may also be used to reduce heat loss in this zone.

In certain cases, it is preferred to use electrical installations 245 that branch to the ends of the crucible 200 and allow the crucible to be heated by an electric heater.

Figures 13 and 14 show another embodiment involving the supply of additional air. In this embodiment, the glass or the like pre-feed tank is designated 246 and the crucible with thread pullers at the bottom thereof is designated 247. · A supply channel 250 is connected to the manifold 249.

The current 12A leaves the unit 251 so that the upper current limit is close to the secondary jet outlet 36 and the glass inlet 37 *

On the downstream side of the feed openings 37 is a unit comprising a downstream plate 252 which is hollow, including a manifold 253 fed by a line 254; the manifold is provided with a series of risers and 255 from which holes 256 flow additional air to a downstream of the fiber supply holes formed by the glass feed holes and the outlet holes formed by the secondary jets.

As shown in Fig. 14, the jet outlets, the glass supply openings, and the additional gas supply openings are arranged to extend relative to each other into groups extending relative to each other in the flow direction, each group forming a defibering station.

With regard to the operation of the defibering system in the case of the use of auxiliary gas as just described, it should be noted that the pressure of the auxiliary gas used can be of the order of 0.5-2 bar and preferably from 0.8 to 1.2 bar.

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In a plant with about 80 fiberization stations according to the embodiment of Figures 1-8, the amount of air flow used as the auxiliary gas may be in the order of 15-30 Nm ^ / h and preferably from about 17 to 25 Nm ^ / h.

The kinetic energy of the auxiliary jet per unit volume must be considerably less than that of the secondary jet.

Claims (8)

13 59782 A method of making fibers from a thermoplastic material, such as glass, comprising providing a main gas stream flowing along a surface and bounding one side of a surface with at least one secondary gas jet having a smaller cross section but greater kinetic energy per unit volume than the main gas stream to cause this secondary gas jet to penetrate the main gas stream to form an interaction zone and the thermoplastic material is introduced into the interaction zone in a stretchable state, characterized by contacting the additional gas jet A method according to claim 1, characterized in that the additional gas jet is introduced into contact with the main gas stream in the immediate vicinity of the inlet point where the thermoplastic material is fed to the interaction zone. A method according to claim 1 or 2, characterized in that the additional gas jet flows along the surface restricting the main gas flow downstream of the thermoplastic material supply openings. An apparatus for performing the method of claim 1, wherein the method comprises making fibers from a thermoplastic material, comprising a main gas stream (12A) generator (202, 203) having an outlet, at least one secondary gas jet generator (221, 220, 207) having a gas jet motion. the energy per unit volume is greater than that of the main gas stream, this gas jet generator comprising one or more outlets (36) having a cross section smaller than the main gas stream outlet and directing the secondary jet transversely to the main gas stream to form an interaction zone , having at least one supply port (37) adapted to direct the substance in the drawable state into the zone where the secondary gas jet penetrates the main gas stream, the surface (209, 227, 252) along which the main gas flow passes downstream of the substance supply port 59782 14, characterized in that it comprises means (214, 215, 216, 236-239, 230-234, 240, 253, 254) with an outlet opening (300, 256) for directing the flow of additional gas jet from the main gas stream and the secondary gas jet, the outlet of the additional gas jet being located downstream of the substance inlet (37) with respect to the flow of the main gas stream (12A). Device according to Claim 4, characterized in that the outlet opening (300, 256) of the additional gas jet generator is located in the region of the upstream edge of the main gas flow restricting surface (209, 227 * 252). Device according to claim 4 or 5, characterized in that the additional gas jet generator comprises a gas distribution channel (214, 230) communicating with at least one opening directed towards the attack edge (213, 234) of the main gas flow restricting surface (209, 227). Device according to one of Claims 4 to 6, with a plurality of secondary gas jet outlets (36) located transversely to the main gas stream (12A), the thermoplastic material supply source being provided with a plurality of feed openings (37), each of which is supplied with a the outlet opening is formed by a gap (300) extending transversely to the main gas flow along the substance supply openings. Apparatus according to claim 5, having a plurality of secondary gas jet outlets (36) located transverse to the main gas stream, the thermoplastic feed source being provided with a plurality of feed openings, each of which is supplied with a filament, characterized by an additional gas jet outlet located near the surface (25). upstream edge, comprises a plurality of holes separated transversely to the main gas flow, each located downstream of the substance supply port.