Glass yarn manufacturing apparatus and glass yarn manufacturing method

Abstract

To provide a glass yarn manufacturing apparatus and a glass yarn manufacturing method capable of manufacturing a multifilament glass yarn from a plurality of rod-like glass base materials.SOLUTION: An apparatus for producing a glass yarn including a plurality of filaments, the apparatus including: a fixing part that holds a plurality of rod-shaped glass preforms vertically downward in a predetermined arrangement; and a heating furnace that is disposed below the fixing part and includes an upper opening, an inert gas inlet, a heater, and a lower opening. The heating furnace is configured to heat and melt the plurality of glass base materials with the heater under an inert gas atmosphere supplied from the inert gas inlet to draw the plurality of glass base materials into a plurality of filaments, and to output the plurality of filaments from the lower opening.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a glass filament manufacturing apparatus and a glass filament manufacturing method. [Background technology]

[0002] Glass yarns containing multiple filaments (hereinafter also referred to as "multifilament") are used in various technical fields such as electronic devices, building materials, vehicles, aircraft, and ships. For example, glass cloth woven from multifilament glass yarns is widely used as a material for printed wiring boards of electronic devices.

[0003] A conventional method for producing a multifilament glass yarn is a melt spinning method. The melt spinning method generally involves placing glass raw materials in a melting furnace, blowing a flame onto them to melt them, and passing the molten glass through a bushing having multiple spinnerets to pull out multiple glass filaments. Thereafter, a sizing agent is applied to the pulled out multiple glass filaments, which are then bundled into a single strand and wound up on a winding device.

[0004] In addition to the melt spinning method, a conventional method for producing multifilament glass yarns includes a method in which a plurality of glass rods are heated, melted, and drawn. For example, Patent Document 1 describes a synthetic quartz glass strand production apparatus having heater means for melting a plurality of synthetic quartz glass rods. This synthetic quartz glass strand production apparatus lowers a plurality of synthetic quartz glass rods into the heater means and continuously pulls out the ends of the molten synthetic quartz glass rods from below the heater means at high speed to produce a synthetic quartz glass long fiber.

[0005] Patent Document 2 also describes a method for producing quartz glass filaments by heating and drawing a quartz glass ingot to produce thick quartz glass fibers with a diameter of 100 to 300 μm, and then heating and drawing the thick quartz glass fibers using a burner flame of a mixed gas of oxygen and hydrogen or in an electric furnace.

[0006] On the other hand, a method for producing a glass fiber consisting of a single filament (hereinafter also referred to as "monofilament") used as an optical fiber includes a method of heating and melting a single optical fiber preform in a drawing furnace and drawing it. For example, Patent Document 3 describes a method in which an optical fiber preform is placed in a drawing chamber in a cylindrical muffle tube provided in a furnace body, and the optical fiber preform is heated and melted by a heater installed in the space outside the muffle tube between the furnace body and the muffle tube, and then drawn. In a drawing furnace for producing such optical fiber, inert gas such as nitrogen is supplied to the space outside the muffle tube containing the heater and the insulating material surrounding it, in order to prevent the insulating material from being burned due to contact with oxygen contained in the outside air. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-099377 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-011484 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-131427 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present disclosure is to provide a glass yarn manufacturing apparatus and a glass yarn manufacturing method capable of manufacturing a multifilament glass yarn from a plurality of rod-shaped glass preforms. [Means for solving the problem]

[0009] Examples of embodiments of the present disclosure are listed below. [1] 1. An apparatus for producing a glass thread comprising a plurality of filaments, said apparatus comprising: a fixing unit that holds a plurality of rod-shaped glass base materials vertically downward in a predetermined arrangement; a heating furnace disposed below the fixing portion and having an upper opening, an inert gas inlet, a heater, and a lower opening; the fixing unit is configured to move downward while holding the glass base material, thereby inserting the plurality of glass base materials into the heating furnace through the upper opening, The heating furnace is configured to heat and melt the plurality of glass preforms with the heater in an inert gas atmosphere supplied from the inert gas inlet, stretch the glass preforms into a plurality of filaments, and eject the plurality of filaments from the lower opening. [2] Item 1. The glass fiber manufacturing apparatus according to item 1, wherein the upper opening of the heating furnace is provided with a lid having a plurality of insertion openings arranged to correspond to the predetermined arrangement of the plurality of glass base materials, and the plurality of glass base materials are inserted into the heating furnace through the plurality of insertion openings, respectively. [3] 3. The glass filament manufacturing apparatus according to item 2, wherein the inner diameters of the plurality of insertion openings are greater than the diameters of the plurality of glass preforms by 0.01 mm or more and 0.1 mm or less. [4] Item 4. The glass filament manufacturing apparatus according to item 2 or 3, wherein the insertion port has a glass pipe. [5] Item 4. The glass filament manufacturing apparatus according to item 2 or 3, wherein the lid is made of glass, whereby the inner surface of the insertion port is made of glass. [6] 5. The glass fiber manufacturing apparatus according to item 4, wherein the heating furnace further comprises a heat insulating material fitted between the upper opening and the lid, the heat insulating material having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion holes, and the pipe passes through the heat insulating material. [7] Item 6. The glass fiber manufacturing apparatus according to item 5, wherein the heating furnace further has a heat insulating material fitted between the upper opening and the lid, the heat insulating material has a plurality of openings arranged to correspond to the arrangement of the plurality of insertion openings, and the diameters of the plurality of openings are larger than the diameters of the plurality of insertion openings. [8] 8. A glass fiber manufacturing apparatus according to any one of items 1 to 7, for manufacturing a silica glass fiber including a plurality of silica glass filaments. [9] The glass fiber manufacturing device according to any one of items 1 to 8, wherein the predetermined arrangement is an arrangement in which the plurality of glass base materials are arranged in a positional relationship selected from a triangular lattice shape, a square lattice shape, a concentric circle shape, a honeycomb lattice shape, a linear shape, and a combination thereof, or in a positional relationship obtained by thinning out some of the glass base materials from these positional relationships, and the arrangement as a whole is arranged in a shape selected from a polygonal shape, a circular shape, an elliptical shape, and a combination thereof.

[10] 10. The glass filament manufacturing apparatus according to any one of items 1 to 9, wherein the plurality of glass preforms includes 10 to 2000 glass preforms.

[11] 11. The glass filament manufacturing apparatus according to any one of items 1 to 10, wherein the diameter of the plurality of glass preforms is 0.3 mm or more and 10 mm or less.

[12] 1. A method for producing a glass yarn comprising a plurality of filaments, the method comprising: a step of inserting a plurality of rod-shaped glass base materials, while being held in a predetermined arrangement, into a heating furnace having an upper opening, an inert gas inlet, a heater, and a lower opening, into which an inert gas is supplied from the inert gas inlet; heating and melting the plurality of glass preforms with the heater in the inert gas atmosphere to draw them into a plurality of filaments, and letting the plurality of filaments out through the lower opening; winding the plurality of filaments extending from the lower opening; A method for producing glass filaments, comprising:

[13] Item 13. The method according to item 12, wherein the upper opening of the heating furnace is provided with a lid having a plurality of insertion openings arranged to correspond to the predetermined arrangement of the plurality of glass base materials, and the plurality of glass base materials are inserted into the heating furnace through the plurality of insertion openings, respectively.

[14] Item 14. The method according to item 13, wherein the inner diameters of the plurality of insertion holes are greater than the diameters of the plurality of glass base materials by 0.01 mm or more and 0.1 mm or less.

[15] 15. The method according to item 13 or 14, wherein the insertion port has a glass pipe.

[16] 15. The method according to item 13 or 14, wherein the lid is made of glass, whereby the inner surface of the insertion opening is made of glass.

[17] Item 16. The method according to item 15, wherein the heating furnace further includes a thermal insulator fitted between the upper opening and the lid, the thermal insulator having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion holes, and the pipe passes through the thermal insulator.

[18] Item 17. The method according to item 16, wherein the heating furnace further includes a heat insulating material fitted between the upper opening and the lid, the heat insulating material having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion openings, and the diameters of the plurality of openings are larger than the diameters of the plurality of insertion openings.

[19] 19. The method according to any one of items 12 to 18, wherein the plurality of rod-shaped glass base materials are silica glass.

[20] 19. The method according to any one of items 12 to 19, wherein the predetermined arrangement is an arrangement in which the plurality of glass preforms are arranged in a positional relationship selected from a triangular lattice shape, a square lattice shape, a concentric circle shape, a honeycomb lattice shape, a linear shape, and a combination thereof, or in a positional relationship obtained by thinning out some of the glass preforms from the above positional relationships, and the arrangement as a whole is arranged in a shape selected from a polygonal shape, a circular shape, an elliptical shape, and a combination thereof. [twenty one] 21. The method according to any one of items 12 to 20, wherein the plurality of glass preforms includes 10 to 2000 glass preforms. [twenty two] 22. The method according to any one of items 12 to 21, wherein the diameter of the plurality of glass base materials is 0.3 mm or more and 10 mm or less. [twenty three] 23. The method according to any one of items 12 to 22, further comprising the step of cleaning the glass base material before the step of inserting the glass base material into the heating furnace. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a glass yarn manufacturing apparatus and a glass yarn manufacturing method that can manufacture a multifilament glass yarn from a plurality of rod-shaped glass preforms. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of a glass filament manufacturing apparatus according to the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing an example of a fixing part in the present disclosure. [Figure 3] FIG. 3 is a schematic diagram showing an example of a predetermined arrangement of glass preforms in the present disclosure. [Figure 4] FIG. 4 is a schematic diagram showing an example of a predetermined arrangement of glass preforms in the present disclosure. [Figure 5] FIG. 5 is a schematic diagram showing an example of the configuration of the upper opening of the heating furnace according to the present disclosure. [Figure 6] FIG. 6 is a schematic diagram showing an example of the configuration of the upper opening of the heating furnace according to the present disclosure. [Figure 7] FIG. 7 is a schematic diagram showing an example of an inert gas inlet of a heating furnace according to the present disclosure. [Figure 8] FIG. 8 is a schematic diagram showing an example of the shape of the heater of the heating furnace according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments. The upper and lower limit values ​​of each numerical range in the following embodiments can be arbitrarily combined to form any numerical range.

[0013] Glass thread manufacturing device The glass fiber manufacturing apparatus of the present disclosure is an apparatus for manufacturing a glass fiber containing a plurality of filaments (hereinafter also referred to as a "multifilament glass fiber" or simply as a "glass fiber"). FIG. 1 is a schematic diagram showing an example of the glass fiber manufacturing apparatus of the present disclosure. As shown in FIG. 1, the glass fiber manufacturing apparatus 100 includes a fixing unit 20 that holds a plurality of rod-shaped glass preforms 10 facing vertically downward in a predetermined arrangement, a heating furnace 30 disposed below the fixing unit 20, and a winding means 40. The heating furnace 30 includes an upper opening 31, an inert gas inlet 32, a heater 33, and a lower opening 34. The glass fiber manufacturing apparatus of the present disclosure has the above-described configuration and is therefore capable of manufacturing a multifilament glass fiber from a plurality of rod-shaped glass preforms. Since there is no need to manufacture a glass fiber having an intermediate fiber diameter before achieving the desired fiber diameter, the manufacturing process is simplified compared to conventional methods that first go through a process of manufacturing thick glass fibers from a glass preform. Furthermore, since the glass fiber manufacturing apparatus of the present disclosure draws multiple glass preforms in a clean environment under an inert gas atmosphere, it is believed that it can provide a multifilament glass fiber having an improved surface condition, for example, with less surface deposits, compared to conventional manufacturing apparatuses and methods that involve melt spinning in air or drawing in air using a flame or electric furnace. Furthermore, while conventional drawing furnaces for monofilament glass fiber for optical fiber are specialized for producing monofilament glass fiber, they are not at all intended for producing multifilament glass fiber, and the glass fiber manufacturing apparatus of the present disclosure is also believed to be technically significant in that it provides a technology that allows multifilament glass fiber to be produced in a drawing furnace.

[0014] <Fixed part> The fixing unit 20 is configured to insert multiple glass preforms 10 into the heating furnace 30 through the upper opening 31 of the heating furnace 30 by moving downward while holding the glass preforms 10 facing vertically downward in a predetermined arrangement. The fixing unit is preferably configured to slowly descend at a predetermined speed so as to maintain a substantially constant height of the portion where the glass preform melts (hereinafter referred to as the "core portion") during the production of the multifilament glass yarn. The descending speed of the fixing unit depends on the diameter of the glass preform, but is preferably 0.1 mm / min to 10 mm / min, more preferably 0.5 mm / min to 5 mm / min, and even more preferably 1.0 mm / min to 3 mm / min.

[0015] (holding means) The manner in which the fixing portion holds the glass preforms in a predetermined arrangement is not particularly limited. The fixing portion preferably includes one or more holding members having a plurality of holes arranged in a predetermined arrangement. By passing the glass preforms through the holes in the holding member, the plurality of glass preforms can be hung vertically downward in a predetermined arrangement. The upper ends of the plurality of glass preforms are preferably provided with stoppers of a size or shape that prevents them from passing through the holes in the holding member, preventing them from falling from the fixing portion. The stoppers can be formed, for example, by processing the upper ends of the glass preforms into a spherical shape larger than the holes in the holding member, or into a flat shape that does not pass through the holes in the holding member. Alternatively, the stoppers can be formed by attaching another member to the upper ends of the glass preforms, such as by wrapping tape around them or by covering them with a cap. In addition to or instead of the stoppers, the fixing portion may include a gripping portion such as a clip to grip the upper ends of the glass preforms.

[0016] FIG. 2 is a schematic cross-sectional view of a fixing unit according to a preferred embodiment of the present disclosure. In the embodiment shown in FIG. 2, the fixing unit 20 includes two holding members 21 each having a plurality of holes aligned in a predetermined array. The holding members 21 are arranged vertically and spaced apart so that the positions of the plurality of holes are aligned. The two holding members 21 allow the plurality of glass preforms 20 to hang vertically downward in a predetermined array by passing the glass preforms 10 through the aligned holes. The use of two holding members 21 spaced apart in the vertical direction facilitates positioning of the glass preforms 10, enabling stable spinning. The upper ends of the plurality of glass preforms 10 each include a spherical stopper 11 larger than the holes in the holding members 21, preventing them from falling off the fixing unit 20.

[0017] (arrangement of glass matrix) The predetermined arrangement of the glass preforms is not particularly limited. For example, it is preferable that the plurality of glass preforms be arranged in a positional relationship selected from a triangular lattice, a square lattice, a concentric circle, a honeycomb lattice, a linear pattern, and combinations thereof. The positional relationship of the plurality of glass preforms may be a positional relationship obtained by thinning out some of these positions. Since various patterns are possible for the positional relationship of the plurality of glass preforms, a positional relationship selected from a triangular lattice, a square lattice, and combinations thereof, or a positional relationship obtained by thinning out some of these positions, is more preferable. The overall shape of the predetermined arrangement of the plurality of glass preforms (i.e., the shape defined by the glass preforms located at the outermost positions in the predetermined arrangement) is preferably a shape selected from a polygon, a circle, an ellipse, and combinations thereof. From the viewpoint of uniform heat distribution, it is more preferable that the overall shape of the predetermined arrangement be a shape selected from a circle and a regular polygon, such as a square, a regular pentagon, a regular hexagon, or a regular polygon with more than two sides. On the other hand, when dividing multiple filaments into two or more strands, from the viewpoint of ease of division, it is more preferable that the overall shape of the predetermined arrangement is a shape selected from a rectangle, an oval, and a combination thereof.

[0018] FIG. 3 schematically illustrates a predetermined arrangement of glass preforms in a preferred embodiment of the present disclosure. In FIG. 3(a), multiple glass preforms are arranged in a triangular lattice-like positional relationship, forming a regular hexagon as a whole. In FIG. 3(a), a total of 163 glass preforms can be arranged. This arrangement provides a high density of glass preforms, and various numbers and patterns of arrangements can be achieved by thinning out portions of the arrangement. For example, by thinning out portions of the arrangement in FIG. 3(a), an arrangement with a honeycomb lattice-like central portion and a wide triangular lattice-like peripheral portion can be achieved, as shown in FIG. 3(b). Alternatively, an approximately concentric arrangement can be achieved, as shown in FIG. 3(c). Arrangements of any pattern can be achieved depending on the temperature distribution in the heating furnace, the positions at which the multiple filaments are divided, and other factors.

[0019] FIG. 4 is a schematic diagram illustrating a predetermined arrangement of glass preforms in another preferred embodiment of the present disclosure. FIG. 4(a) illustrates an arrangement in which multiple glass preforms are arranged in a square lattice-like configuration, forming a rectangle as a whole. In FIG. 4(a), a total of 126 glass preforms can be arranged, with 6 vertical and 21 horizontal lines. This arrangement also provides a high density of glass preforms, and various arrangements and patterns can be achieved by thinning out portions of the arrangement. For example, thinning out the central column of the arrangement in FIG. 4(a) can result in an arrangement (total of 120 glass preforms) that combines two arrangements, each with 60 glass preforms arranged in a square lattice-like configuration, as shown in FIG. 4(b). This arrangement makes it easy to divide, for example, 120 filaments into two strands of 60 each.

[0020] <Heating furnace> The heating furnace 30 has an upper opening 31, an inert gas inlet 32, a heater 33, and a lower opening 34. The heating furnace 30 is configured to heat and melt multiple glass preforms 10 with the heater 33 under an inert gas atmosphere supplied from the inert gas inlet 32, thereby drawing the multiple filaments 13, and ejecting the multiple filaments 13 from the lower opening 34. Typically, as schematically shown in FIG. 1 , the heating furnace 30 includes a furnace core tube 35, and the heater 33 is configured to cover at least a portion of the furnace core tube 35. The heating furnace 30 may include a glass preform insertion tube 36 having an upper opening 31, a furnace body 37 that houses the furnace core tube 35 and the heater 33, and a filament discharge tube 38 having a lower opening 34. By including the glass preform insertion tube 36, the filament discharge tube 38, or both in addition to the furnace body 37, the temperature distribution and the flow of the inert gas within the furnace core tube 35 can be easily controlled.

[0021] (Top opening) The upper opening 31 of the heating furnace 30 has one or more insertion openings 31 through which multiple glass preforms 10 can be inserted in a predetermined arrangement. For example, the upper opening preferably has a lid having one or more insertion openings. When the upper opening has the lid, it is more preferable that the lid has multiple insertion openings arranged to correspond to the predetermined arrangement of the multiple glass preforms. In this case, the multiple glass preforms are inserted into the heating furnace through the multiple insertion openings arranged to correspond to the predetermined arrangement. By having such a lid on the upper opening, it is possible to easily position the multiple glass preforms and perform stable spinning. Furthermore, it is possible to maintain a uniform heat distribution and inert gas atmosphere within the heating furnace and prevent foreign matter from entering the heating furnace. Details of the predetermined arrangement of the glass preforms are as described above.

[0022] The inner diameter of the insertion opening is preferably 0.01 mm or more and 0.1 mm or less, more preferably 0.01 mm or more and 0.05 mm or less, and even more preferably 0.02 mm or more and 0.03 mm or less, greater than the diameter of the glass preform. When the inner diameter of the insertion opening is within the above range, positioning of the multiple glass preforms is easy, and stable spinning can be performed.

[0023] The lid preferably includes a plurality of pipes (hereinafter also referred to as "guide pipes") penetrating through each of the plurality of insertion openings. The guide pipes can function as insertion openings that pass the glass preform through the pipes and guide the glass preform into the heating furnace. When the lid includes a plurality of guide pipes, each guide pipe preferably extends from the top of the lid (any position away from the top surface of the lid) through each insertion opening of the lid to the bottom of the lid (any position away from the bottom surface of the lid). This makes it easy to position the glass preform and enables stable spinning. The guide pipes are preferably glass pipes. By including glass guide pipes in the lid, the glass preform is less likely to be scratched than with a metal guide pipe, enabling stable spinning. In other words, the glass preform is easily scratched when it comes into contact with a metal member, and scratches on the glass surface may lead to filament breakage. In this regard, the inventors have focused on the fact that glass is less likely to be scratched even when it comes into contact with other glass materials, and have found that by using a glass pipe as the guide pipe, it is possible to effectively prevent scratches on the surface of the glass base material and suppress filament breakage. This effect is more pronounced as the diameter of the glass filaments in the glass yarn becomes smaller and the number of filaments in the glass yarn increases.

[0024] From the viewpoint of more effectively preventing scratches on the surface of the glass base material, it is preferable that the hardness of the glass pipe used as the guide pipe is similar to that of the glass base material. The hardness of glass is determined by the composition of the glass, and it is preferable that the glass pipe has a glass composition similar to that of the glass base material. For example, when quartz glass is used as the glass base material, it is preferable that the glass pipe is also made of quartz glass.

[0025] In an embodiment in which the lid has a guide pipe, the inner diameter of the guide pipe is preferably 0.01 mm or more and 0.1 mm or less, more preferably 0.01 mm or more and 0.05 mm or less, and even more preferably 0.02 mm or more and 0.03 mm or less, greater than the diameter of the plurality of glass preforms. In this case, the inner diameter of the insertion opening of the lid is configured to be sufficiently large to allow the guide pipe to pass through.

[0026] In an embodiment in which the lid has guide pipes, the lid may further have a plate (hereinafter also referred to as a "guide plate") having a plurality of guide holes for holding the plurality of guide pipes. When the lid further has a guide plate, the guide plate is preferably arranged above the insertion openings with the positions of the plurality of guide holes aligned with the positions of the plurality of insertion openings, with a gap therebetween. Each guide pipe preferably extends from the top of the guide plate (any position away from the top surface of the guide plate), through each guide hole in the guide plate and each insertion opening in the lid, to the bottom of the lid (any position away from the bottom surface of the lid). This allows the plurality of guide pipes to be held vertically, which makes it easy to position the glass preform and enables stable spinning.

[0027] On the other hand, in an embodiment in which the lid does not have a guide pipe, it is preferable that the lid is made of glass, thereby making the inner surface of the insertion opening glass. For example, the lid can be a glass plate, preferably a quartz glass plate, having multiple insertion openings arranged to correspond to the predetermined arrangement of multiple glass preforms. By using a glass lid, the glass preform is less likely to be scratched than a metal lid, allowing for stable spinning. This effect is more pronounced as the glass filament diameter becomes smaller and the number of filaments increases. From the perspective of more effectively preventing scratches on the surface of the glass preform, it is preferable that the hardness of the glass used as the lid is approximately the same as that of the glass preform, and therefore it preferably has a glass composition similar to that of the glass preform. For example, when quartz glass is used as the glass preform, it is preferable that the lid is also made of quartz glass. Note that when the lid is made of glass, radiant light from the heating furnace may leak out of the furnace, so it is preferable to optionally layer a light-shielding member on top of it to block the light. For example, the heat insulating material described below may be used as the light-shielding member.

[0028] In an embodiment in which the lid does not have a guide pipe, the lid may further have a plate (hereinafter also referred to as a "guide plate") having a plurality of guide holes that can guide the glass preform to the insertion opening. When the lid further has a guide plate, the guide plate is preferably arranged above the insertion openings with a gap therebetween, with the positions of the plurality of guide holes aligned with the positions of the plurality of insertion openings. This makes it easy to position the glass preform and enables stable spinning. In this embodiment, the guide plate is preferably a glass plate. By using a glass guide plate, the glass preform is less likely to be scratched than a metal guide plate, enabling stable spinning. This effect is more pronounced as the filament diameter of the glass yarn is smaller and the number of filaments is greater. From the viewpoint of more effectively preventing scratches on the surface of the glass preform, it is preferable that the hardness of the glass used as the guide plate is similar to that of the glass preform, and therefore it preferably has a glass composition similar to that of the glass preform.

[0029] The upper opening of the heating furnace preferably further comprises a heat insulating material. By providing the upper opening with a heat insulating material, the inflow of outside air can be suppressed and the temperature distribution inside the heating furnace can be maintained uniform, thereby enabling stable spinning. The location of the heat insulating material is not particularly limited as long as it is above the furnace core tube, and examples include between the upper opening and the lid, midway through the glass base material insertion tube, etc. For example, the heating furnace preferably further comprises a heat insulating material fitted between the upper opening and the lid.

[0030] The heat insulating material has one or more openings so that a plurality of glass base materials can be inserted in a predetermined arrangement. For example, the heat insulating material preferably has a plurality of openings arranged to correspond to the positions of the plurality of insertion openings in the lid. The heat insulating material is not particularly limited as long as it is a heat-resistant insulating material, and examples thereof include porous carbon materials, preferably carbon felt.

[0031] If the heating furnace has an insulating material, it is preferable that the insulating material does not come into direct contact with the glass preform as it passes through it. For example, in an embodiment in which the lid has a guide pipe, the guide pipe is preferably arranged to penetrate the insulating material, and more preferably arranged to extend to any position away from the underside of the insulating material. On the other hand, in an embodiment in which the lid does not have a guide pipe, it is preferable that the diameters of the multiple openings in the insulating material are each larger than the diameters of the multiple insertion openings in the lid. The present inventors have noticed that when multiple glass preforms are drawn into multiple filaments using a drawing furnace equipped with an insulating material at the upper opening of the heating furnace, the filaments often break. After extensive research, the inventors have noticed that the insulating material sometimes adheres to the glass preform as it passes through the insulating material. More specifically, when the preform passes through a carbon felt for 100 mm, the carbon felt sometimes adheres to approximately 10 places. Therefore, the inventors further deliberately attached carbon felt to quartz glass, heated it as is at 1750°C for 60 seconds, and observed the surface condition after heating using a scanning electron microscope (SEM). They confirmed that defects such as cracks had occurred on the glass surface. That is, although this was previously unforeseen, the inventors discovered that the insulating material attached to the glass surface was the cause of filament breakage and outer diameter fluctuations. In this regard, by preventing the insulating material from adhering to the surface of the glass base material as described above, filament breakage, scratches on the glass yarn surface, and outer diameter fluctuations caused by the insulating material can be effectively suppressed, thereby enabling stable spinning. This effect is more pronounced the smaller the filament diameter of the glass yarn and the greater the number of filaments.

[0032] FIG. 5 is a schematic cross-sectional view of the upper opening of a heating furnace according to a preferred embodiment of the present disclosure. As shown in FIG. 5( a), the upper opening 31 of the heating furnace 30 includes a lid 50 and an insulating material 60 fitted between the lid 50 and the upper opening 31. The lid 50 has multiple insertion openings 51 arranged to correspond to a predetermined arrangement of multiple glass preforms. Each insertion opening 51 has a guide pipe 52 that guides the glass preforms through the insertion openings 51 into the heating furnace. The guide pipes 52 are made of glass (quartz glass pipes). The lid 50 also has a guide plate 53 having multiple guide holes 54 arranged to correspond to the predetermined arrangement of the multiple glass preforms. The guide plate 53 is positioned above the insertion opening 51 at intervals, with the positions of the multiple guide holes 54 aligned with the positions of the multiple insertion openings 51. The insulating material 60 has multiple openings 61 arranged to correspond to the arrangement of the multiple insertion openings 51 of the lid 50. Each guide pipe 52 extends from a position away from the upper surface of the guide plate 53, passes through each guide hole 54 and each insertion opening 51, and further passes through the opening 61 of the insulating material 60 to a position away from the lower surface of the insulating material 60. FIG. 5(b) is a schematic cross-sectional view of the upper opening 31 of the heating furnace 30 shown in FIG. 5(a) when multiple glass preforms 10 are inserted. As shown in FIG. 5(b), in this embodiment, the guide pipes 52 of the lid 50 are held by the insertion openings 51 of the lid 50 and the guide holes 54 of the guide plate 53, so that the multiple guide pipes 52 can be held vertically. As a result, the glass preforms can be easily positioned and spinning can be performed stably. Furthermore, because the guide pipes 52 are made of glass, they are less likely to scratch the glass preform than metal guide pipes, allowing for stable spinning. Furthermore, since the guide pipe 52 extends to a position away from the underside of the insulating material 60, the glass base material 10 does not come into direct contact with the insulating material 60, and filament breakage caused by the insulating material, as well as scratches on the glass thread surface and fluctuations in outer diameter, can be effectively suppressed, resulting in stable spinning.

[0033] FIG. 6 is a schematic cross-sectional view of an upper opening of a heating furnace according to a preferred embodiment of the present disclosure. As shown in FIG. 6(a), the upper opening 31 of the heating furnace 30 includes a lid 50 and an insulating material 60 inserted between the upper opening 31 and the lid 50. The lid 50 has a plurality of insertion openings 51 arranged to correspond to a predetermined arrangement of a plurality of glass preforms. The lid 50 is made of glass (quartz glass plate), and the inner surface of the insertion opening 51 is therefore made of glass. The insulating material 60 has a plurality of openings 61 arranged to correspond to the arrangement of the plurality of insertion openings 51 of the lid 50. The diameters of the plurality of openings 61 in the insulating material 60 are each larger than the diameters of the plurality of insertion openings 51 in the lid 50. FIG. 6(b) is a schematic cross-sectional view of the upper opening 31 of the heating furnace 30 shown in FIG. 6(a) when a plurality of glass preforms 10 are inserted therein. As shown in Figure 6(b), in this embodiment, the lid 50 is made of glass, which makes it less likely for the glass preform to be scratched than a metal lid, allowing for stable spinning. Furthermore, the insulating material 60 is placed under the lid 50, preventing radiant light from leaking from the heating furnace to the outside. Furthermore, the diameters of the multiple openings 61 in the insulating material 60 are each larger than the diameters of the multiple insertion openings 51 in the lid 50, preventing the glass preform 10 from directly contacting the insulating material 60. This effectively prevents breakage of the filament, scratches on the surface of the glass filament, and fluctuations in the outer diameter, which may be caused by the insulating material. As a result, stable spinning is possible.

[0034] (inert gas inlet) The heating furnace 30 has an inert gas inlet 32 ​​for supplying an inert gas into the heating furnace. By having the inert gas inlet, the heating furnace can draw multiple glass preforms under an inert gas atmosphere, thereby providing a multifilament glass yarn with less surface deposits. Examples of inert gases include argon gas, nitrogen gas, helium gas, and combinations thereof. The inert gas is preferably argon gas. The inert gas can be supplied, for example, by connecting an inert gas supply means (not shown), such as an inert gas supply pipe, to the inert gas inlet.

[0035] The location of the inert gas inlet may be, for example, above (upstream from the spinning direction) the portion where the glass preform melts (hereinafter referred to as the "core"), or below (downstream from the spinning direction), preferably above the core. By having the inert gas inlet above the core, the inert gas flows from top to bottom through the core, generating a downward (downflow) flow exiting from the lower opening. In the present disclosure, regardless of the location of the inert gas inlet on the furnace's exterior, if the inert gas generates a downflow in the core, the inert gas inlet is considered to be "above the core." Even if the inert gas flow is a downflow, a portion of the inert gas supplied into the heating furnace may exit from the upper opening of the heating furnace. The temperature inside the heating furnace is very important for stable spinning, and the flow of inert gas significantly affects temperature control inside the heating furnace. In this regard, the inventors have found that in the glass fiber manufacturing apparatus of the present disclosure, a downflow of inert gas reduces breakage of filaments and fluctuations in the outer diameter of the glass fiber, enabling stable spinning.

[0036] The inert gas may be preheated before being supplied through the inert gas inlet to maintain a uniform temperature within the heating furnace, or the inert gas may be supplied into the heating furnace at room temperature, preheated as it passes through the heating furnace, and then introduced into the furnace tube. The temperature of the inert gas within the furnace tube may be, for example, 300°C or higher, 400°C or higher, 500°C or higher, 1000°C or higher, or 1500°C or higher. The upper temperature limit, which can be arbitrarily combined with these lower limit values, is, for example, 2200°C or lower, 2100°C or lower, or 2000°C or lower.

[0037] FIG. 7 schematically illustrates an inert gas inlet configuration in a preferred embodiment of the present disclosure. In the configuration shown in FIG. 7( a), the inert gas inlet 32a is provided in a portion of the glass preform insertion tube 36 located above the muffle tube 35 of the heating furnace 30. As indicated by the white arrow, most of the inert gas supplied from the inert gas inlet 32a flows downward within the muffle tube 35 and exits through the lower opening 34. In the configuration shown in FIG. 7( b), the inert gas inlet 32b is provided in a portion (lower portion) of the furnace body 37 of the heating furnace 30. As indicated by the black arrow, most of the inert gas supplied from the inert gas inlet 32b passes outside the muffle tube 35, flows into the muffle tube 35 through a gap provided at the top of the muffle tube 35, flows downward through the muffle tube 35, and exits through the lower opening 34. In the embodiment of Figure 7(b), the inert gas inlet 32b appears to be below the core section from the outside of the heating furnace, but since the inert gas is configured to generate a downflow in the core section, the inert gas inlet 32b is considered to be "above the core section."

[0038] (Heater and furnace tube) The heating furnace 30 includes a heater 33 for heating and melting the plurality of glass preforms 10 introduced therein. Typically, as shown in Fig. 1, the heater 33 is disposed so as to cover at least a portion of a furnace tube 35. The heater is not particularly limited as long as it can heat the inside of the furnace tube to a temperature at which the glass preforms are melted, and examples thereof include a carbon heater.

[0039] The lower limit of the temperature inside the muffle tube varies depending on the type of glass, but can be, for example, 1400°C or higher, 1600°C or higher, 1800°C or higher, 2000°C or higher, or 2200°C or higher. When quartz glass is used as the base material, the temperature inside the muffle tube is preferably 2200°C or higher. The upper limit of the temperature that can be arbitrarily combined with these lower limit values ​​is, for example, 2500°C or lower, 2400°C or lower, or 2300°C or lower.

[0040] The furnace core tube 35 is, for example, a tube made of carbon. The shape of the furnace core tube can be, for example, a cylindrical shape, an elliptical cylindrical shape, a rectangular cylindrical shape, or a combination thereof. From the viewpoint of easily achieving a uniform temperature distribution within the furnace core tube, the furnace core tube is preferably cylindrical. On the other hand, when dividing multiple filaments into two or more strands, from the viewpoint of easy division, the furnace core tube is preferably an elliptical cylindrical shape, a rectangular cylindrical shape, or a combination thereof.

[0041] FIG. 8 is a schematic diagram showing an example of the shape of a heater of a heating furnace according to a preferred embodiment of the present disclosure. FIG. 8(a) shows a cylindrical heater suitable for use with a cylindrical furnace tube. Because it is easy to achieve uniform temperature distribution in the circumferential direction and to densely arrange the glass preforms, it can be used in a small electric furnace. The arrangement of the glass preforms can be, for example, a regular hexagonal triangular lattice arrangement, as shown in FIGS. 3(a) to 3(c), or an arrangement obtained by thinning out the hexagonal triangular lattice arrangement. FIG. 8(b) shows an elliptical cylindrical heater suitable for use with an elliptical cylindrical furnace tube. The simple arrangement of the glass preforms may potentially shorten the electric furnace in the longitudinal direction. The arrangement of the glass preforms can be, for example, a rectangular square lattice arrangement, as shown in FIGS. 4(a) and 4(b), or an arrangement obtained by thinning out the hexagonal triangular lattice arrangement. A linear arrangement in which the glass preforms are arranged in a line may also be used. Figures 8(c) and (d) show rectangular heaters suitable for use with a rectangular cylindrical furnace tube. The arrangement of the glass preforms is simple, which may allow the electric furnace to be shortened in the longitudinal direction. Figure 8(d) has divided heaters, which allows for adjustment of the temperature distribution. The glass preforms can be arranged, for example, in a rectangular square lattice pattern as shown in Figures 4(a) and (b), or in an arrangement obtained by thinning out the rectangular square lattice pattern. A linear arrangement in which the glass preforms are lined up in a row may also be used.

[0042] (bottom opening) The furnace 30 has a bottom opening 34 for drawing the molten and drawn filaments. The bottom opening may, for example, include a lid with one or more drawing ports through which the filaments to be gathered into a single strand can be drawn together.

[0043] <Winding means> The winding means 40 is configured to wind the multiple filaments 34 emerging from the lower opening 34. At this time, the multiple filaments 34 are gathered into one or more strands 12 each including multiple filaments, forming a multifilament glass yarn. As schematically shown in FIG. 1 , it is preferable to use a sizing device 41 to apply a sizing agent (glue) to the multiple filaments, gather the filaments into a strand 12, and then wind the strand 12 with the winding device 41. Applying a sizing agent can reduce the fuzziness of the multifilament glass yarn. The multiple filaments 34 may all be combined into a single strand 12, or the multiple filaments 34 may be divided into multiple strands 12.

[0044] Although resin coating is commonly used to protect monofilament glass yarns for optical fibers from breakage due to scratches or bending, resin coating is not necessary in the manufacturing apparatus and method disclosed herein. In particular, when the diameter of the filaments constituting the glass yarn is small, the glass yarn is resistant to scratches and bending, and therefore a sizing agent can be applied directly to the glass yarn without applying a resin coating.

[0045] The winding speed can be adjusted appropriately depending on the desired filament diameter, etc., and can be, for example, 500 m / min or more and 5000 m / min or less, 600 m / min or more and 4500 m / min or less, 700 m / min or more and 4000 m / min or less, or 800 m / min or more and 3500 m / min or less.

[0046] <Glass base material> The material of the glass base material is not limited, but is preferably quartz glass. That is, the glass fiber manufacturing apparatus is preferably a manufacturing apparatus for manufacturing a quartz glass fiber containing multiple quartz glass filaments. Quartz glass needs to be melted at a high temperature of approximately 2200°C. However, using conventional melt spinning methods, it is extremely difficult to melt quartz glass at such a high temperature and then pass it through a bushing to be drawn. Furthermore, it is believed that there are few materials for forming bushings that can withstand such high temperatures when heated in air. In contrast, the glass fiber manufacturing apparatus and method disclosed herein, in a preferred embodiment, are highly technically significant in that they can simultaneously draw multiple quartz glass base materials into multifilament glass fibers of the desired fiber diameter. Furthermore, in a method in which quartz glass is heated and melted in the atmosphere, using a flame, or an electric furnace, and then drawn, inorganic oxides may adhere to the surface of the glass fiber or hydroxyl groups may be introduced due to the influence of oxygen and moisture contained in the air, potentially preventing the low dielectric tangent characteristic of quartz glass from being fully exhibited. In contrast, the glass fiber manufacturing apparatus and method disclosed herein draws a quartz glass base material using a heater under an inert gas atmosphere, and therefore it is believed that it is possible to obtain a multifilament glass fiber made of quartz glass with less surface deposits and a low dielectric loss tangent.

[0047] The number of glass preforms that can be heated, melted, and drawn at one time using the glass filament manufacturing apparatus of the present disclosure is preferably 10 or more and 2000 or less. The lower limit of the number of glass preforms may be, for example, 20 or more, 30 or more, 40 or more, or 50 or more. The upper limit of the number of glass preforms may be, for example, 1500 or less, 1000 or less, 800 or less, 600 or less, 500 or less, 400 or less, 300 or less, 200 or less, or 100 or less. When the number of glass preforms is 10 or more, a glass filament with a large number of filaments can be produced. On the other hand, when the number of glass preforms is 2000 or less, the heat distribution between the filaments is easily uniform, and the probability of filament breakage or the like occurring is reduced, making production easier.

[0048] The diameter of the glass preform is preferably 0.3 mm or more and 10 mm or less. The lower limit of the diameter of the glass preform may be, for example, 0.5 mm or more, 1.0 mm or more, 1.5 mm or more, or 2.0 mm or more. The upper limit of the diameter of the glass preform may be, for example, 9.5 mm or less, 9.0 mm or less, 8.5 mm or less, 8.0 mm or less, 7.5 mm or less, 7.0 mm or less, 6.5 mm or less, 6.0 mm or less, 5.5 mm or less, 5.0 mm or less, 4.5 mm or less, or 4.0 mm or less. When the diameter of the glass preform is 0.3 mm or more, the fixing part can be lowered over a longer period of time, thereby extending the replacement span of the glass preform and improving productivity. On the other hand, when the diameter of the glass preform is 10 mm or less, a larger number of glass preforms can be arranged per unit area, allowing the production of a multifilament glass yarn with a large number of filaments.

[0049] The length of the glass base material is preferably 300 mm or more and 3000 mm or less, more preferably 400 mm or more and 2000 mm or less, and even more preferably 500 mm or more and 1500 mm or less. If the glass base material is 300 mm or more, the replacement span of the glass base material becomes longer, leading to improved productivity. On the other hand, if the glass base material is 3000 mm or less, replacement of the glass base material becomes easier.

[0050] Glass thread The glass fiber obtained by the glass fiber manufacturing apparatus of the present disclosure is a multifilament glass fiber. The upper limit of the average fiber diameter of the filaments constituting the glass fiber is preferably 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less. The lower limit of the average fiber diameter of the filaments, which can be arbitrarily combined with these upper limits, is preferably 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, 6 μm or more, 7 μm or more, 8 μm or more, 9 μm or more, or 10 μm or more. Conventional manufacturing apparatuses and methods for monofilament glass fiber for optical fiber are typically specialized in manufacturing monofilament glass fiber having a diameter exceeding 100 μm, and are not at all intended to manufacture multifilament glass fiber having a thin filament diameter of 100 μm or less. In contrast to this, the glass filament manufacturing apparatus and method of the present disclosure, in a preferred embodiment, have great technical significance in that they are capable of manufacturing multifilament glass filaments having a thin filament diameter of 100 μm or less as described above.

[0051] The number of filaments constituting the multifilament glass yarn may correspond to the number of filaments in the glass base material, and is preferably 10 to 2000. The lower limit of the number of filaments may be, for example, 20 or more, 30 or more, 40 or more, or 50 or more. The upper limit of the number of filaments may be, for example, 1500 or less, 1000 or less, 800 or less, 600 or less, 500 or less, 400 or less, 300 or less, 200 or less, or 100 or less.

[0052] The glass yarn preferably has a sizing agent (glue) on the glass surface. By having a sizing agent, the fluffing of the glass yarn can be reduced. Note that glass yarns for optical fibers generally have a resin coating to protect the filaments from breakage due to scratches or bending, but the glass yarns of the present disclosure do not need to have a resin coating. In particular, when the diameter of the filaments constituting the glass yarn is small, it is preferable that the sizing agent be applied directly to the glass surface without a resin coating, in order to make the filaments more resistant to scratches and bending.

[0053] <<Method for manufacturing glass filaments>> The method for manufacturing a glass filament includes an insertion step of inserting multiple rod-shaped glass preforms into a heating furnace, a drawing step of heating and melting the multiple glass preforms and drawing them into multiple filaments, and a winding step of winding the multiple filaments. In the insertion step, the multiple rod-shaped glass preforms are inserted into the heating furnace through an upper opening while being held in a predetermined arrangement. The heating furnace has an upper opening, an inert gas inlet, a heater, and a lower opening, and an inert gas is supplied through the inert gas inlet. In the drawing step, the multiple glass preforms are heated and melted by the heater in an inert gas atmosphere and drawn into multiple filaments, and the multiple filaments are discharged from the lower opening. Then, in the winding step, the multiple filaments discharged from the lower opening are wound using a winding means. The method for manufacturing a glass filament of the present disclosure can be performed, for example, using the glass filament manufacturing apparatus described above.

[0054] <Glass base material cleaning process> The method for manufacturing a glass filament preferably further includes a step of cleaning the glass base material before the step of inserting a plurality of glass base materials into a heating furnace. By cleaning the surface of the glass base material, it is possible to effectively suppress breakage of the filament and fluctuations in outer diameter caused by surface dirt. The smaller the filament diameter of the glass filament and the greater the number of filaments, the more susceptible to the influence of dirt, so the effect of cleaning the surface of the glass base material is remarkable.

[0055] Methods for cleaning the glass base material include, for example, wiping the surface of the glass base material with a solvent, and immersing the glass base material in a solvent. When cleaning multiple glass base materials after arranging them, it is difficult to wipe all of the glass base materials. Therefore, cleaning the glass base material is preferably performed by immersing the glass base material in a solvent. From the viewpoint of high cleaning power, it is preferable to immerse the glass base material in a solvent and apply ultrasonic waves to it.

[0056] Examples of solvents used to clean glass base materials include water and alcohols such as ethanol and isopropanol (IPA). From the perspective of removing grease and easily removable deposits, organic solvents such as alcohol are preferred. When cleaning stains that are resistant to organic solvents, such as epoxy adhesives, piranha cleaning, which uses a mixture of sulfuric acid and hydrogen peroxide, is preferred. Furthermore, when removing the surface layer of glass, hydrofluoric acid or ammonium fluoride may be used as a solvent.

[0057] <Insertion process, stretching process, and winding process> The inserting step, the drawing step, and the winding step can be performed by the fixing unit, the heating furnace, and the winding means of the glass filament manufacturing apparatus, respectively, using the glass preform described above. For details, the explanations in the respective sections of "Glass filament manufacturing apparatus" are cited. [Example]

[0058] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples.

[0059] Example 1 Several pieces of glass base material made of quartz glass, each 1 mm in diameter and 1000 mm in length, were prepared as glass base materials. One end of the glass base material was machined into a spherical shape as shown in Figure 2 to form a stopper.

[0060] Two holding members were prepared, each with multiple holes arranged in a triangular lattice-like hexagon, as shown in Figure 3(a). As shown in Figure 2, multiple glass base materials were passed through the holes in the two holding members, and the holding members were fixed to the fixing parts, allowing the glass base materials to hang down. At this time, the arrangement of the glass base materials was set to 50 pieces, as shown in Figure 3(b). After the glass base materials were held in the fixing parts, the surfaces of the glass base materials were wiped with ethanol to clean them before inserting them into the heating furnace.

[0061] As shown in Figure 5(a), a lid was attached to the upper opening of the heating furnace, which had a plurality of quartz glass guide pipes arranged to correspond to the arrangement of the glass preforms and a guide plate to hold the guide pipes, and a heat insulating material was inserted between the lid and the upper opening. The inner diameter of the guide pipe was configured to be 0.02 mm to 0.03 mm larger than the diameter of the glass preforms. The length of the guide pipe was configured to penetrate the heat insulating material and extend to a position away from the bottom surface of the heat insulating material.

[0062] A cylindrical carbon furnace tube was used as the muffle tube, and a cylindrical carbon heater as shown in Figure 8(a) was used as the heater. An inert gas supply pipe was connected to the inert gas inlet provided in the glass base material insertion tube of the heating furnace, and argon gas was supplied into the heating furnace at room temperature, preheated in the heating furnace, and then supplied into the muffle tube. The argon gas flow in the muffle tube was downward (downflow). The temperature inside the muffle tube was controlled to 2200°C by adjusting the output of the carbon heater and the flow rate of the argon gas.

[0063] The fixing part was lowered at a speed of 1.5 mm / min, and the glass preform was inserted into a heating furnace through a guide pipe while maintaining the arrangement of the glass preform. The glass preforms were melted in the heating furnace and drawn into multiple filaments, which were then discharged from the lower opening of the filament discharge pipe. A sizing agent was applied to the multiple filaments using a sizing device, and the filaments were bundled into a single strand. The strand was then wound onto a bobbin using a winding device. The winding speed was 1000 m / min.

[0064] As a result of the above, a multifilament glass yarn made of quartz glass was produced, with a filament diameter of 5 μm and 50 filaments. During the production, no breakage of the filaments occurred, and the surface of the obtained glass yarn was clean. [Explanation of symbols]

[0065] 10 glass base material, 11 stopper, 13 filament, 20 fixing portion, 21 holding member, 30 heating furnace, 31 upper opening, 32 inert gas inlet, 33 heater, 34 lower opening, 35 furnace core tube, 36 glass base material insertion tube, 37 furnace body, 38 filament discharge tube, 40 winding means, 41 sizing device, 42 winding device, 50 lid, 51 insertion port, 52 guide pipe, 53 guide plate, 54 guide hole, 60 heat insulating material, 61 opening, 100 glass thread manufacturing device

Claims

1. 1. An apparatus for producing a glass thread comprising a plurality of filaments, said apparatus comprising: a fixing unit that holds a plurality of rod-shaped glass base materials vertically downward in a predetermined arrangement; a heating furnace disposed below the fixing portion and having an upper opening, an inert gas inlet, a heater, and a lower opening; the fixing unit is configured to move downward while holding the glass base materials, thereby inserting the plurality of glass base materials into the heating furnace through the upper opening, The heating furnace is configured to heat and melt the plurality of glass preforms with the heater in an inert gas atmosphere supplied from the inert gas inlet, and draw the plurality of glass preforms into a plurality of filaments, and to eject the plurality of filaments from the lower opening.

2. The glass fiber manufacturing apparatus of claim 1, wherein the upper opening of the heating furnace is provided with a lid having a plurality of insertion openings arranged to correspond to the predetermined arrangement of the plurality of glass base materials, and the plurality of glass base materials are each inserted into the heating furnace through the plurality of insertion openings.

3. 3. The glass filament manufacturing device according to claim 2, wherein the inner diameters of the plurality of insertion openings are greater than the diameters of the plurality of glass preforms by 0.01 mm or more and 0.1 mm or less.

4. 4. The glass filament manufacturing device according to claim 2, wherein the insertion opening has a glass pipe.

5. 4. The glass filament manufacturing device according to claim 2 or 3, wherein the cover is made of glass, whereby the inner surface of the insertion opening is made of glass.

6. The glass fiber manufacturing apparatus according to claim 4, wherein the heating furnace further comprises an insulating material inserted between the upper opening and the lid, the insulating material having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion holes, and the pipe passes through the insulating material.

7. The glass fiber manufacturing apparatus according to claim 5, wherein the heating furnace further comprises an insulating material inserted between the upper opening and the lid, the insulating material having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion openings, and the diameters of the plurality of openings are each larger than the diameters of the plurality of insertion openings.

8. The glass fiber manufacturing apparatus according to any one of claims 1 to 3, for manufacturing a silica glass fiber containing a plurality of silica glass filaments.

9. The glass fiber manufacturing apparatus according to any one of claims 1 to 3, wherein the predetermined arrangement is an arrangement in which the plurality of glass base materials are arranged in a positional relationship selected from a triangular lattice shape, a square lattice shape, a concentric circle shape, a honeycomb lattice shape, a linear shape, and a combination thereof, or in a positional relationship obtained by thinning out some of the glass base materials from these positional relationships, and the arrangement as a whole is arranged in a shape selected from a polygonal shape, a circular shape, an elliptical shape, and a combination thereof.

10. The glass filament manufacturing apparatus according to any one of claims 1 to 3, wherein the plurality of glass preforms includes 10 to 2000 glass preforms.

11. The glass filament manufacturing apparatus according to any one of claims 1 to 3, wherein the diameter of the plurality of glass base materials is 0.3 mm or more and 10 mm or less.

12. 1. A method for producing a glass yarn comprising a plurality of filaments, the method comprising: a step of inserting a plurality of rod-shaped glass base materials, while being held in a predetermined arrangement, into a heating furnace having an upper opening, an inert gas inlet, a heater, and a lower opening, into which an inert gas is supplied from the inert gas inlet; a step of heating and melting the plurality of glass preforms by the heater in the inert gas atmosphere, and drawing the plurality of glass preforms into a plurality of filaments, and letting the plurality of filaments exit from the lower opening; winding the plurality of filaments coming out of the lower opening; A method for producing glass filaments, comprising:

13. The method according to claim 12, wherein the upper opening of the heating furnace is provided with a lid having a plurality of insertion openings arranged to correspond to the predetermined arrangement of the plurality of glass base materials, and the plurality of glass base materials are inserted into the heating furnace through the plurality of insertion openings, respectively.

14. The method according to claim 13 , wherein the inner diameters of the plurality of insertion holes are greater than the diameters of the plurality of glass base materials by 0.01 mm or more and 0.1 mm or less.

15. 15. The method of claim 13 or 14, wherein the insertion port comprises a glass pipe.

16. 15. The method of claim 13 or 14, wherein the lid is made of glass, whereby the inner surface of the insertion opening is made of glass.

17. 16. The method of claim 15, wherein the heating furnace further comprises an insulating material fitted between the upper opening and the lid, the insulating material having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion openings, and the pipe passing through the insulating material.

18. 17. The method according to claim 16, wherein the heating furnace further comprises an insulating material interposed between the upper opening and the lid, the insulating material having a plurality of openings arranged to correspond to the arrangement of the plurality of insertion openings, and the diameters of the plurality of openings are each larger than the diameters of the plurality of insertion openings.

19. The method according to any one of claims 12 to 14, wherein the plurality of rod-shaped glass base materials are silica glass.

20. The method according to any one of claims 12 to 14, wherein the predetermined arrangement is an arrangement in which the plurality of glass preforms are arranged in a positional relationship selected from a triangular lattice shape, a square lattice shape, a concentric circle shape, a honeycomb lattice shape, a linear shape, and a combination thereof, or in a positional relationship obtained by thinning out some of the glass preforms from the above positional relationships, and the arrangement as a whole is selected from a polygonal shape, a circular shape, an elliptical shape, and a combination thereof.

21. The method according to any one of claims 12 to 14, wherein the plurality of glass preforms includes 10 to 2000 glass preforms.

22. The method according to any one of claims 12 to 14, wherein the diameter of the plurality of glass base materials is 0.3 mm or more and 10 mm or less.

23. The method according to any one of claims 12 to 14, further comprising the step of cleaning the glass preforms before the step of inserting the glass preforms into the heating furnace.

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