NO142168B - APPARATUS FOR REVERSING A MELTABLE FIBER MATERIAL TO FIBER - Google Patents

Description

The present invention relates to an apparatus for converting a molten drawable material, preferably glass, into fibres.

The present application represents a further development of the apparatus described in the Norwegian design document no. 139954.

The applicant has found that it is advantageous to maintain a certain distance between the feed orifices and the boundary or outer limit of the main flow (gas flow). Thus, such a determined distance will simplify the regulation of the atmosphere surrounding the inlet crucible or inlet funnel in which the molten material is located and flows from. Furthermore, such a distance or separation will make it possible to use certain heating means in the funnel which cannot be easily used in connection with systems where the feed mouths for the glass are located exactly at the outer limit of the main stream.

By means of said separation, one can operate between the softened material and the main stream with a free space which is of great importance.

According to an important feature of the invention

the molten material is directed towards the interaction zone through a space between the feed mouth and the main flow in that, due to this space, the fiber web can be removed from all construction parts that are located downstream of the interaction zone and to reduce the mutual thermal influence between the material-melting means and the supply means for the main flow.

According to another particularly favorable feature of the invention, the secondary jet is directed - for the provision of the aforementioned co-operation zone - from a point which is located in said space above the boundary for the main flow and at a distance from the glass's feed opening in order to reduce the mutual thermal influence between the supply means for glass mass, main gas flow and secondary jet .

The invention proposes in particular to direct the secondary beam obliquely towards the main flow in relation to the glass's feeding direction.

According to the above, the present invention relates to an apparatus for converting a molten drawable material, preferably glass, into fibers comprising devices for forming a primary gas flow comprising an outlet mouth, one or more means for forming secondary gas jets with a kinetic energy per . unit volume greater than that of the former stream to enable the secondary jet(s) to penetrate the stream to create a zone of mutual influence, as well as one or more feed orifices for feeding drawable material to the zone where the secondary jet penetrates the primary stream, and this apparatus is characterized by the fact that the feed mouth(s) is arranged at a distance of 10-100 mm above the boundary surface of the main stream, that the mouth for the secondary jet is located at a distance of from 5-10 mm above the upper boundary surface of the main stream, that the axis of the device for creating the secondary jet is directed at an angle of 45-85° in relation to the direction of movement of the main stream, and that the axial distance between the mouth for the secondary jet 6g the feed mouth for thermoplastic material is 4-10 mm in the direction of movement of the main stream.

In the following, examples of designs are described

of apparatus according to the invention with reference to the attached drawings where:

Fig. 1 shows a section through a blowing post comprising means for providing a main gas flow, means for providing a secondary jet and means for advancing a glass melt, the latter consisting of a glass mass feeding mouth arranged above (higher than) and at a certain distance from the upper boundary of the main gas stream. Fig. 2 shows an analogous section as fig. 1, but a different embodiment where the feed mouth for the glass mass has a different design. Fig. 3 is a diagram showing the shape of a number of mouths for introducing glass mass of the type shown in fig. 2, as well as their arrangement in relation to the secondary jet nozzles. Fig. 4 is a vertical section through an apparatus comprising several fiber blowing stations, the section is taken through plane 4-4 in fig. 6. Fig. 5 is an analogous section as fig. 4, but made through plane 5-5 in fig. 6.

Fig. 6 is a view of certain parts shown in fig. 4 and

5, but viewed in an upward direction, the figure shows in detail the mutual location of the outflow orifices for glass and secondary jet according to the embodiment of fig. 4 and 5.

Fig. 7 still shows an embodiment analogous to Fig. 2, but also including a device for introducing an additional gas on the opposite side of the main flow in relation to the outflow openings for glass and secondary jet.

In the drawings, the main gas flow is indicated at 12A

and the mouths for secondary gas and glass mass have the reference numbers 36 and 37 respectively, similar to the reference numbers in the various drawings in the above-mentioned Norwegian design document.

Reference is first made to fig. 1 where at 200 you see

an outlet funnel or crucible which is combined with a suitable supply system for glass such as e.g. a filling funnel or chute 201. The main gas flow comes out of the part 202 at a height that is significantly lower (below) the outlet opening 200. The outlet for the secondary gas, 36, forms the open end of a pipe 203 with supply from the larger pipe 204, in connection with a burner or other source of secondary gas supplied through line 205. It should be noted that the radiant tube 203

is placed at a certain angle in relation to the axis through the main flow 12A and furthermore that the nozzle opening 36 is at a certain distance above the boundary of the main flow coming from the pipe 202.

The secondary flow and the main gas have this effect

that together they form a co-operation zone which is described in detail in the aforementioned explanatory document, which zone is located

quite precisely vertically below the feed mouth for the glass 37. The glass enters in the form of a string denoted S, which falls by gravity from the opening 37 and enters the interaction zone between the secondary jet and the main gas flow and later into the stretching zone as described in the aforementioned specification.

In the embodiments shown, including fig. 1, the vertical distance between the inlet opening for the glass 3 7 and the outer limit of the main flow 12A is of the order of 10-100 mm. Moreover, the distance between the outflow mouth for the carrier gas jet 36 and the delimitation of the main gas flow is in the range of 5-10 mm.

In these embodiments, the distance between the axes of the openings 36 and 37 measured in the upstream-downstream direction of the main flow 12A is 4-10 mm. Due to the location and spacing between different parts that form the fiber blow port, the jet tube 203 and consequently the jet coming out of the tube according to the invention forms an angle relative to the axis through the main stream 12A of between 45 and 85°, preferably angles of 75-85° are used . The relationship between the angles used and the spaces between them should be such that a zone of cooperation is created between the secondary jet and the main gas flow at a point that lies fairly precisely vertically below the feed mouth for the glass 37. It is also advantageous to place the jet tube 203

and consequently the outlet mouth for the secondary jet so that the opening for this is located upstream of the glass string S in the direction of the main flow. The inclined position of the beam tube 203 will send out a secondary beam in a direction which generally runs across the main flow, but which has a component in the direction downstream of the main flow, which facilitates the fiber stretching and the advancement of the blown fiber with the main flow.

Each fiber blowing post constructed in this way and as shown in fig. 1 generally works in the way that is described in detail in the previously mentioned explanatory document.

The active quantities, including the kinetic energy of the main stream and the secondary jet in the operating zone as well as the temperature, velocity of the main gas and secondary jet as well as the temperature of the glass and the relationship between the dimensions of the mouths with regard to glass mass and secondary gas, can be as stated in the design document, although it may be beneficial if certain parameters vary -are outside the limits mentioned there. As already mentioned, e.g. present invention a large distance between the feed mouth for the glass above the nearest boundary for the main flow. You can use other variants, some of which are described later.

With the apparatus proposed according to the invention, smaller lower limits can be used for the ratio between the kinetic energy of the secondary beam and the main current in the operating zone compared to the apparatus described in the specification. Effective results can thus be achieved by keeping the aforementioned ratio between the kinetic energies of the carrier gas and the main stream between 4:1 and 35:1.

With the apparatus according to the invention, the dimensions for the mouth of the secondary jet can be considerably smaller than suggested in the specification. E.g. according to the present invention, the mouth of the secondary jet can be smaller than the glass feed mouth, i.e. from approximately 1/6 of the glass feed mouth's dimension and up to approximately the same dimension as this. The dimension of the secondary jet mouth can vary from 0.3 to 2.5 mm in diameter. Application of a secondary jet orifice with small dimensions often requires high gas pressure under otherwise the same conditions. Secondary jet pressures of, for example, 2-25 atmospheres can be used.

In designs that include secondary beams with

small diameter, the distance between the axes through the secondary jet mouth and the glass feed mouth, measured in the upstream-downstream direction of the main flow, can be around 3-4 times the diameter of the secondary jet outflow mouth or between approx. 1

and 10 mm.

In connection with an embodiment as shown in fig. 1

air currents will be formed by the impact of the secondary jet from the opening 36, indicated by arrow 206 and these induced currents will affect the position of the glass string S.

as the currents tend to pull the glass strand towards the secondary beam to an increasingly greater extent the closer it gets to the boundary of the main current. This effect is stabilizing because it is thus easier to achieve a constant and stable influx of glass mass in the interaction zone between the secondary jet and the main stream.

Fig. 1 shows that there is a substantial free space between and around the main organs at the blowing station, i.e. the outflow funnel, the pipeline for supplying gas to the secondary gas pipe and the apparatus for providing the main gas flow. Due to this increased space between the elements of the fiber blowing post, the heat transfer between the outflow funnel for glass and the blowing elements for main stream and secondary jet will be reduced. significantly. This gives you an opportunity to regulate the temperature of the glass. This structure also makes it possible to use glass melters with a higher melting temperature or larger outflow quantities from the feed mouth.

One can use a series of fiber traction posts arranged

across the direction of the main current.

The glass feed mouth 37 as shown in fig. 1 forms a simple opening or can be structured as described in detail in connection with fig. 2 and 3. Reference is now made to fig. 2 and 3 where the main organs work in the same way as above although the vertical distance between the feed mouth for the glass, 37,

and the upper boundary of the main stream 12A is not as large as in fig. 1.

In the embodiment in fig. 2 and 3, the two sides of the inlet funnel 200 are lined with an insulating material such as aluminum oxide fibers (e.g. 60% Al 2 O 2 ) as shown at 207, which reduces the heat loss from the outlet crucible and which protects the jet tube 20 3 against the high temperature of the outlet funnel. In order for the outlet funnel to be able to withstand the high temperature in the glass melt, it is normally made of platinum alloy and the insulation described makes it possible to make the other organs such as e.g. the blow pipe 203 of less expensive metal such as stainless steel..

By using an insulation as shown at 20 7 between the outlet funnel and the secondary jet and the associated supply means, a greater temperature difference can be maintained between the glass and the secondary jet. Even though the secondary beam thus has a relatively low temperature, the insulation 207 will make it possible to maintain a relatively high temperature in the glass without excessive heat loss. This system thus enables high production.

One looks at fig. 2 and 3 that the glass passes through the bottom of the inlet funnel through a calibrated nozzle 37c and that the feed mouth is expanded both above and below this calibrated nozzle. The extension above the mouth is shaped like a funnel and facilitates the inflow of the glass mass through the nozzle and out into the reserve pocket from which the glass finally flows out. The lower extension forms a small reserve from which the glass, as mentioned, flows out. The circumference of the mouth 37 can be 2-3 times the circumference of the calibration nozzle 37c and the entire wall part of the pocket is moistened by the glass, which contributes to better stability for the immediately hanging glass mass from the mouth, especially at high temperature. Because of the reserve pocket, the glass bulb or cone formed will have a larger dimension and consequently form a longer cone than without such a pocket, which also enables a greater distance between the outflow point of the glass and the point or area where the fiber begins to pull in the cone. The increase in the distance between the point at which the fiber begins to form and the feed mouth will reduce the tendency of the fiber to collect on the apparatus parts located near the fiber blowing station.

Although the pocket that terminates the feed mouth for the glass can be circular, it is an advantage to use an oval pocket whose longest axis lies in the same direction as the direction of flow of the main current, as can be seen from fig. 3.

With such a device for the influx of glass

as shown in fig. 2 and 3, the opening through the calibrated nozzle 37c will form the actual glass feed orifice or quantity-regulating opening.

In the embodiment in fig. 2 and 3, the pressure of the secondary jet can advantageously be stronger than described in the previously mentioned explanatory note on<*> due to the distance between the opening for the secondary jet and the main flow. Consequently, the pressure of the secondary jet is advantageously 2-10 atmospheres in connection with an opening diameter of approx. 2 mm, and when the opening has approx. 1 mm diameter, the pressure can be 2-25 atmospheres.

The possibility of using high pressures and large kinetic energies for the secondary jet means that you can increase the amount of glass produced that is delivered from the feed mouth and improve the uniformity of the feed as well as the stability of the formed hanging cone Under the feed mouth, which gives better and smoother fiber- products.

The possibility of using high pressures for the secondary jet and the fact that the outflow mouths for the secondary jet and the glass are at a distance from the main flow are factors that are of great importance in being able to maintain a greater interaxial distance between the outflow mouths for the secondary jet and glass. These factors will also facilitate the use of larger glass feed orifices than the outflow opening for the secondary jet, e.g. 1-2 times the cross-sectional opening of the secondary jet when using a secondary jet pressure of up to 12 atmospheres and 2-3 times in connection with a jet pressure of 12-25 atmospheres.

In the embodiment described above in connection with fig. 2 and 3, the width of the reserve pocket in the glass feed orifice measured perpendicular to the flow direction of the main stream 12A may in a typical case be 1.3 times the diameter through the secondary jet outflow orifice and the length may be twice the width.

In connection with fig. 2 and 3, and when using a glass mass with a composition as in ex. II stated in the aforementioned explanatory document, operating conditions and results have been arrived at which appear in the following table:

If one now looks at fig. 4, 5 and 6, you see again

an embodiment where the outlet crucible or funnel is combined with an upper part or main funnel 201. A pipe element 202 conducts the main flow 12A generally in l/brisontal direction under the outlet funnel.

In this case, the funnel is provided with two rows of feed mouths 37A and 37B, which are arranged in a zigzag pattern as shown in fig. 6. The supply pipe for the secondary jet 204 is provided with branches which have mouths for secondary jets 36B linked to the feed mouths for the glass 37B, and is further provided with additional pipes for the supply of secondary gas through mouths 36A combined with glass feed mouths 37A. All the mouths 36A, 36B, 37A and 37B are located at a certain distance above the upper boundary of the main flow 12A. This design not only includes one row of fiber blowing posts arranged in a zigzag pattern, but also enables, with this distribution, the maintenance of a vertical distance between the mouths and the upper boundary of the main stream.

In certain embodiments described above, with which a large fiber production can be achieved, the fibers sometimes tend to pass the main stream 12A without being completely drawn. You then get a premature stiffening of parts of the fibers and, consequently, a tendency to deposit large-diameter fibers in the formed fiber mats. Errors of this type can be avoided by using an embodiment as shown in fig. 7. In the embodiment shown in fig. 7, the fiber blowing apparatus is arranged in the same general way as fig. 2 and 3 show, but a wall or plate 208 is also installed at the outlet of the main stream 202. The plate is located below the outlet of the main stream and has a curvature so that the plate moves away from the main stream in its direction. The wall has an extension 209 arranged in such a way that a gap 210 is formed which gives the possibility of blowing out an air sheet or layer through the pipeline 211, possibly another gas.

With such a design with curved surfaces on the parts 208 and 209, a guide surface effect is obtained which provides a diversion or deflection of the main flow with the following increase in the distance between the glass's feed mouth and the main flow. This effect is of the same type as achieved by the execution

on fig. 11 in the previously mentioned layout document, but the effect of the wall is enhanced by the possibility of blowing in the air gap 210. Consequently, the thickness of the main flow is increased in the hot area where the fiber blowing takes place.

Such a device can be used to remove the tendency of the fibers to fall through the main flow and to avoid a premature stiffening of the fibers before the desired draw is achieved. IN

an apparatus as shown in fig. 7, the blowing pressure that sends air through the gap 210 can be 3-6 atmospheres.

Claims (1)

1. Apparatus for converting a molten, drawable material, preferably glass, into fibers comprising means for forming a primary gas flow (12) comprising an outlet orifice, one or more means (203) for forming secondary gas jets with a kinetic energy per unit volume greater than that of the former stream (12) to enable the secondary jet (e) to penetrate the stream to create a zone of mutual influence, and one or more feed orifices (37) for feeding drawable material to the zone where the secondary jet penetrates into the primary stream, characterized in that the feed mouth (el) (37) is arranged at a distance of 10-100 mm above the boundary surface for the main stream, that the mouth (36) for the secondary stream is located at a distance of from 5-10 mm above the upper boundary surface of the main stream, that the axis of the device (203) for creating the secondary jet is directed at an angle of 45-85° in relation to the direction of movement of the main stream (12), and that the axial distance between the mouth (36) for the secondary jet and the feed mouth (37) for thermoplastic material is 4-10 mm in the direction of movement of the main flow (12).