GB2053889A - Attenuated glass fibre manufacture - Google Patents

Abstract

Glass filaments 3 fed from orifices of furnace 4 into flame jet 2 of burner 1 to produce attenuated fibres (glass wool) are alternately thick and thin in at least one direction. Fig. 4 shows a preferred arrangement of orifices. <IMAGE>

Description

SPECIFICATION A method and equipment for producing fine glass fibers The present invention relates to improvements in fabrication of attenuated glass fibers, namely, glass wool from glass rods or primary glass filaments and, more particularly, to improvements in a method of and an apparatus for fabricating attenuated glass fibers from the glass filaments by means of a so-called flame jet blast process.

The production rate of attenuated glass fibers or economy of the fabrication of the glass fibers by means of a so-called flame jet blast process depends, as shown in Fig. 1, upon the volume of primary glass filaments 3 simultaneously fed into fast and high temperature hot blast 2 ejected from a burner 1.

It is, accordingly, preferable to feed as many glass filaments as possible to the hot blast 2 ejected from the burner 1 in order to fabricate maximum quantity of the attenuated glass fibers per fuel of unit weight consumed in the burner 1 for ejecting the hot blast 2, per one attenuated glass fiber fabricating apparatus.

However, in order to permit the primary glass filaments to be attenuated by the hot blast ejected from the burner into attenuated glass fibers or glass wool of uniform quality, it is necessary to devise the apparatus so that the turbulent flow of the hot blast occurring when the individual primary glass filaments pass the attenuating point therein does not affect the adjacent primary glass filaments and, therefore, there must be at least a predetermined interval among the adjacent primary glass filaments at the attenuating point.

Therefore, when the amount of heat, velocity, width and elevational thickness of the hot blast are once constantly determined in the conventional method of and apparatus for fabricating attenuated glass fibers, the thickness and number of primary glass filaments to be fed into the hot blast ejected from the burner will be automatically determined to thereby decide the quantity of the attenuated glass fibers thus fabricated.

The present invention provides a method of and an apparatus for fabricating attenuated glass fibers, which can increase the production rate of the attenuated glass fibers more than that of the conventional method and apparatus while employing the constant quantity of heat, velocity, width and elevational thickness of the hot blast ejected from the burner.

Accordingly, an object of the present invention is to provide a method of and apparatus for fabricating attenuated glass fibers, which can increase the production rate of the attenuated glass fibers per unit fuel consumed in the burner.

Another object of the present invention is to provide a method of and apparatus for fabricating attenuated glass fibers, which can fabricate the attenuated glass fibers of uniform quality by supplying primary glass filaments of predetermined thickness and those of thinner thickness than the previous filaments disposed alternatively thereamong into the hot blast ejected from the burner.

Yet another object of the present invention is to provide a method of and apparatus for fabricating attenuated glass fibers, which can eliminate the formation of molten glass to increase the flow rate of the molten glass in specified direction atprimary glass filaments spinning time from a spinning furnace bottom with spinning nozzles or orifices and accordingly the occurrence of irregular temperature distribution among the orifices to enable spinning of thick and thin uniform primary glass filaments by arranging large-bore orifices for spinning thick glass filaments and small-bore orifices for spinning thin glass filaments alternatively at least in predetermined one direction on the bottom of the spinning furnace thereof.

Still another object of the present invention is to provide a method of and an apparatus for fabricating attenuated glass fibers, which can easily dispose alternatively thick and thin primary glass filaments into hot blast ejected from the burner.

Still another object for the invention is to provide a method and an apparatus for fabricating attenuated glass fibers, which can uniformly attenuate thick and thin primary glass filaments spinned from a spinning furnace.

The foregoing objects and other objects as well as the characteristic features of the invention will become more readily understandable by the following description and the appended claims when read in conjunction with the accompanying drawings.

Fig. 1 is a schematic side view of an apparatus for fabricating attenuated glass fibers provided with a preferred embodiment of the present invention; Fig. 2 is a perspective view partially of major components of the apparatus of the present invention showing particular arrangement of large-bore and small-bore orifices spinning primary glass filaments of thick and thin sizes; Fig. 3 is a perspective view conceptually showing the state of attenuating both thick and thin primary glass filaments alternatively arranged according to the present invention; Fig. 4 is a plan view of one example of the orifices arrangement on the spinning furnace bottom according to the present invention; and Fig. 5 Is a perspective view similar to Fig. 3 but showing the prior art example.

The method of fabricating attenuated glass fibers according to the present invention is based on the discovery that the provision of a predetermined or wider interval in the elevational direction between the attenuating point lines of thick and thin primary glass filaments spinned from the spinning furnace in the hot blast can permit an advantageous arrangement of the attenuating points of both the thick and thin primary glass filaments without causing any adverse effect on the adjacent primary glass filaments besides the fact that there must be at least a predetermined interval among adjacent primary glass filaments at the attenuating points in order to efficiently attenuate the primary glass filaments in the hot blast ejected from the burner, as described previously.

For this purpose, in the method according to the present invention, thick and thin primary glass filaments are spinned from a spinning furnace.

Then, hot blast most adapted for the thick primary glass filaments is ejected from a burner to attenuate the thick primary glass filaments at the most preferable position therein in the same manner as the conventional attenuating process, normally at the position lower by substantially 2/3 from the uppermost position of the hot blast.

Then, the thick glass filaments are fed at slightly broader interval than the conventional process, and the thin glass filaments are interposed alternatively among the thick glass filaments.

Thus, both the thick and thin primary glass filaments are simultaneously fed into the hot blast, and the thin primary glass filaments are simultaneously attenuated with the thin glass filaments.

The attenuating points of the above thin primary glass filaments can be set at the upper position in the hot blast so as not to adversely affect the attenuation of the thick primary glass filaments such as, for example, at the position lower by substantially 1/3 from the uppermost of the hot blast by selecting the diameter of the primary glass filaments.

As the thin primary glass filaments are fed into the hot blast alternatively with the thick primary glass filaments, the interval of the thin primary glass filaments adjacent to the thick primary glass filaments should, of course, be selected to that which does not adversely affect the attenuation of the thin primary glass filaments.

The above-described method according to the present invention is executed by the apparatus for fabricating attenuated glass fibers as exemplified in Figs. 1 and 2.

Referring now to Fig. 1, a spinning furnace 4 has a number of nozzles or orifices formed in projected manner on the central bottom 5 thereof.

As shown in Fig. 2, the furnace 4 has a number of large-bore orifices 7 for spinning thick primary glass filaments 6 and a number of small-bore orifices 9 for spinning the thin primary glass filaments 8 thinner than the primary glass filaments 6 arranged alternatively in the lines of the direction 0--0.

The apparatus for fabricating attenuated glass fibers according to the present invention thus has the spinning furnace 4, and a primary glass filaments separator 1 O, a pair of feed rollers 11, a support 12, respectively arranged sequentially under the furnace 4 to thereby feed the thick and thin primary glass filaments 6 and 8 into the hot blast ejected at high speed and high temperature from the flame ejecting port 1 3 of a burner 1. Both the thick and thin primary glass filaments 6 and 8 are alternatively arranged and aligned through the separator 10 and the support 12 to be fed into the hot blast 2 ejected from the burner 1.

As shown in Figs. 2 and 3, the thick primary glass filaments 6 have large heat capacity, and, accordingly, are attenuated at the position lower by substantially 2/3 from the uppermost position of the thickness Wof the hot blast 2 as the attenuating points, while the thin primary glass filaments 8 have small heat capacity, and, accordingly, are attenuated at the position lower by substantially 1/3 from the uppermost position of the thickness W of the hot blast 2 as the attenuating points Y.

Both the primary glass filaments 6 and 8 are simultaneously fed at equal speed by the same feed rollers 11 into the hot blast 2 ejected from the burner 1. The difference of the diameters between the thick and the thin primary glass filaments 6 and 8 is absorbed and cancelled to be fed at equal velocity by forming the feed rollers 11 of heat-resisting synthetic rubber or the like.

The primary glass filaments 6 and 8 spinned and drawn from the large-bore orifices 7 and the small-bore orifices 9 at the bottom of the spinning furnace 4 are manually fed through the abovedescribed separator 10, feed rollers 11, and support 12, however, since the large-bore and small-bore orifices 7 and 9 are arranged alternatively at the bottom of the spinning furnace 4, the primary glass filaments are naturally sequentially alternatively fed along the line 0--0 of the orifices in the sequence of the orifices into the hot blast 2 ejected from the burner 1.

Fig. 4 illustrates one preferred arrangement of the large-bore and small-bore orifices at the bottom of the spinning furnace alternatively in two directions of the line P-P and Q-Q in such a manner that the axis of the rollers 11 is inclined at an angle 8 in respect of the line P-P according to the present invention.

This arrangement of the orifices for spinning the primary glass filaments can easily demonstrate the sequential order of the alternative thick and thin glass filaments drawn from the bottom of the spinning furnace as seen from the underside of the spinning furnace.

The advantage of the method of and apparatus for fabricating the attenuated glass fibers of the present invention can be further understood obviously as compared with the conventional ones from the following examples.

That is, according to the conventional method of and apparatus, as shown in Fig. 5, the thickness of the primary glass filaments 14 was set to 435/1, and the distance L of the axes between the adjacent primary glass filaments 14 was set to 1.3 mm. Then, the burner for attenuating the primary glass filaments was conditioned so as to most efficiently attenuate the primary glass filaments, and the supplying speed of the primary glass filaments was also conditioned in the same manner as above. The primary glass filaments were then attenuated under these conditions.

Then, the primary glass filaments of 435,u were alternatively interposed among the primary glass filaments of 375y, and were thus fed into the hot blast ejected from the burner while maintaining the same burner conditions and the same primary glass filaments feeding velocity. The distance of the axes between the thick and the thin primary glass filaments as designated by / in Fig. 3, which is similar to Fig. 5, can be shortened to approximately 1.02 mm in order to obtain the attenuated glass fibers of the same quality as these obtained by the above conventional method and apparatus. The primary glass filaments thus obtained increased their weight by 1 5%.

As the large-bore and small-bore orifices are so arranged at the bottom of the spinning furnace alternatively in one direction to thus spin and draw simultaneously thick and thin primary glass filaments so as to spin the aforementioned thick and thin primary glass filaments, no particular molten glass passage was formed in the spinning furnace, nor irregular temperature orifices took place but uniform primary glass filaments could be obtained.

It should be understood from the foregoing description that, since the method of the present invention is thus constructed and operated, it can increase the production of rate of the attenuated glass fibers per unit fuel consumed in the burner and fabricate the attenuated glass fibers of uniform quality by supplying primary glass filaments of predetermined thickness and those of thinner thickness than the previous filaments disposed alternatively thereamong into the hot blast ejected from the burner.

It should be appreciated that, since the apparatus of the present invention incorporates large-bore orifices for spinning thick primary glass filaments and small-bore orifices for spinning thin primary glass filaments arranged at least in one direction alternatively at the bottom of the spinning furnace, it can eliminate the formation of molten glass in specified direction at primary glass filaments spinning time from the spinning furnace bottom with the spinning orifices and accordingly the occurrence of irregular temperature distribution among the orifices to enable spinning of thick and thin uniform primary glass filaments.

It should also be understood that, since the apparatus of the present invention incorporates the alternative arrangement of the large-bore and small-bore orifices at the bottom of the spinning furnace thereof, it can easily dispose alternatively thick and thin primary glass filaments into hot blast ejected from the burner. It should further be appreciated that, since the apparatus of the present invention is thus constructed and operated, it can uniformly attenuate both the thick and thin primary glass filaments spinned from the spinning furnace in high quality.

Claims (9)

1. A method of fabricating attenuated glass fibers comprising the steps of: simultaneously spinning a plurality of primary glass filaments of predetermined thickness and a plurality of another primary glass filaments of thickness thinner than the primary glass filaments from large-bore and small-bore orifices, respectively in alternative arrangement of a spinning furnace, and feeding the thick and thin primary glass filaments arranged alternatively into the hot blast ejected from a burner to attenuate the primary glass filaments in the hot blast.

2. The method of fabricating attenuated glass fibers according to claim 1, wherein the thick primary glass filaments are attenuated at the position lower by substantially 2/3 from the uppermost position of the hot blast.

3. The method according to claim 1, wherein the thin primary glass filaments are attenuated at the position lower by substantially 1/3 from the uppermost position of the hot blast.

4. The method according to claim 1 , wherein the large-bore and small-bore orifices at the bottom of the spinning furnace are alternatively arranged in two directions of lines at predetermined angle with respect to each other.

5. An apparatus for fabricating attenuated glass fibers comprising: a spinning furnace having a plurality of large-bore orifices for spinning thick primary glass filaments of predetermined thickness and a plurality of small-bore orifices for spinning thin primary glass filaments of thickness thinner than the primary glass filaments arranged alternatively with each other at least in one direction, a pair of feed rollers disposed under said spinning furnace for simultaneously feeding thick and thin primary glass filaments arranged alternatively with each other, and a burner for ejecting hot blast to attenuate the thick and thin primary glass filaments simultaneously.

6. The apparatus for fabricating attenuated glass fibers according to claim 5, wherein the thick primary glass filaments are attenuated at the position lower by substantially 2/3 from the uppermost position of the hot blast ejected from said burner.

7. The apparatus according to claim 5, wherein the thin primary glass filaments are attenuated at the position lower by substantially 1/3 from the uppermost position of the hot blast ejected from said burner.

8. The apparatus according to claim 5, wherein the large-bore and small-bore orifices at the bottom of said spinning furnace are alternatively arranged at least in two directions of lines at predetermined angle with respect to each other.

9. The apparatus according to claim 5, wherein said feed rollers are formed of heat-resisting synthetic rubber to absorb and cancel the difference of the diameters between the thick and the thin primary glass filaments spinned from said spinning furnace to feed the primary glass filaments at equal velocity therebetween.

1 O. Apparatus for fabricating attenuated glass fibers substantially as described herein with reference to the accompanying drawings.