阅读说明：本技术 玻璃微粒子堆积体的制造方法及燃烧器 (Method for producing glass particle deposit and burner ) 是由 三田怜 于 2020-08-31 设计创作，主要内容包括：本发明是一种玻璃微粒子堆积体的制造方法,在反应容器内设置起动杆及燃烧器,将玻璃原料导入到燃烧器,使玻璃原料在燃烧器所形成的火焰内进行火焰水解反应而生成玻璃微粒子,并使所生成的玻璃微粒子堆积于起动杆,从而制造玻璃微粒子堆积体；所述玻璃微粒子堆积体的制造方法包括：在所述燃烧器的最外管外周设置固定辅具,将燃烧器外罩从所述燃烧器的最外管前端插入,使所述固定辅具的一部分夹在该燃烧器外罩与所述燃烧器的最外管之间进行压缩,由此将所述燃烧器外罩固定于所述燃烧器,进而,未被压缩的所述固定辅具的一部分的外径大于插入到所述燃烧器的最外管前端的所述燃烧器外罩的一部分的内径。(The invention is a method for manufacturing glass particle accumulation body, set up starting lever and burner in the reaction vessel, introduce the glass raw materials into the burner, make the glass raw materials carry on the flame hydrolysis reaction in the flame that the burner forms and produce the glass particle, and make the glass particle produced pile up on the starting lever, thus make the glass particle accumulation body; the method for producing a glass fine particle deposited body includes: the burner cover is fixed to the burner by providing a fixing aid around the outermost tube of the burner, inserting a burner cover from the front end of the outermost tube of the burner, and compressing a part of the fixing aid by sandwiching the burner cover and the outermost tube of the burner.)

1. A method for producing a glass fine particle deposit, comprising the steps of providing a starting rod and a burner in a reaction vessel, introducing a glass raw material into the burner, subjecting the glass raw material to flame hydrolysis in a flame formed by the burner to produce glass fine particles, and depositing the produced glass fine particles on the starting rod to produce a glass fine particle deposit; the method for manufacturing a glass fine particle deposited body is characterized in that a fixing aid is provided on the outer periphery of the outermost tube of the burner, a burner cover is inserted from the front end of the outermost tube of the burner, a part of the fixing aid is clamped between the burner cover and the outermost tube of the burner and compressed, thereby fixing the burner cover to the burner, and furthermore, the outer diameter of the part of the fixing aid which is not compressed is larger than the inner diameter of the part of the burner cover inserted to the front end of the outermost tube of the burner.

2. The method for producing a glass particle stack according to claim 1, wherein the fixing aid contains at least one of PTFE, PFA, and polyimide.

3. The method for producing a glass particle stack according to claim 1 or 2, wherein the fixing aid is formed by winding a tape or a film around an outermost tube periphery of the burner.

4. The method for producing a glass particulate deposit according to any one of claims 1 to 3, wherein, when the burner cover is fixed to the burner, the difference between the inner diameter of the burner cover and the outer diameter of the outermost tube of the burner in a cross section perpendicular to the burner longitudinal direction is 0.5mm or more and 4mm or less.

5. The method for producing a glass particulate deposit according to any one of claims 1 to 4, wherein a protruding distance of the tip of the burner cover from the tip of the burner is 20mm or more and 40mm or less.

6. A burner, characterized by comprising:

a multi-tube burner;

a burner housing; and

a fixing aid provided on an outermost tube outer periphery of the multi-tube combustor, and a part of which is sandwiched between the combustor casing and the multi-tube combustor and compressed, thereby fixing the combustor casing to the multi-tube combustor;

an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of a portion of the burner housing.

7. The burner of claim 6, wherein the fixation aid comprises at least one of PTFE, PFA, polyimide.

8. The burner according to claim 6 or 7, wherein the fixing aid comprises a tape or a film wound around the outermost tube circumference of the multi-tube burner.

9. The burner according to any one of claims 6 to 8, wherein when the burner cover is fixed to the multi-tube burner, the difference between the inner diameter of the burner cover and the outer diameter of the outermost tube of the multi-tube burner in a cross section orthogonal to the longitudinal direction of the multi-tube burner is 0.5mm or more and 4mm or less.

10. The burner according to any one of claims 6 to 9, wherein a protruding distance of the front end of the burner cover from the front end of the multi-tube burner is 20mm or more and 40mm or less.

11. The burner according to any one of claims 6 to 10, wherein the fixing aid has an abutment portion against which an end face of the burner housing abuts.

Technical Field

The present invention relates to a method for producing a glass particle deposit and a burner for producing a glass particle deposit by depositing glass particles on a starting rod by an OVD method (outside vapor deposition method), a VAD method (vapor axial deposition method), an MMD method (multi-burner multi-layer deposition method), or the like.

Background

In a conventionally known manufacturing apparatus for manufacturing an optical fiber preform by an OVD method, a reaction is performedA starting rod and a burner for generating glass particles are arranged in the container, SiCl is supplied to the burner₄And depositing glass particles generated by a flame hydrolysis reaction in a flame formed by the burner around the starter rod to form a glass particle deposit.

In such a method for producing a glass particle deposit, it is known that a detachable burner cover (burner cover) is fitted over the tip of a burner in order to prevent adhesion of glass particles to the tip of the burner made of quartz glass, prevent a change in shape of the burner tip due to deterioration, or control the flow of the burner flame (see documents 1, 2, 3, and 4).

Further, a technique is known in which the position or angle of the burner is changed in accordance with the growth of the glass particle deposit. (see documents 5 and 6)

[ background Art document ]

[ patent document ]

[ document 1] Japanese patent laid-open No. Sho 63-110535;

[ document 2] Japanese patent laid-open No. Sho 63-81828;

[ document 3] Japanese patent laid-open No. 2010-96378;

[ document 4] Japanese patent laid-open No. 2006-199527;

[ document 5] Japanese patent laid-open publication No. 2017-071513;

[ document 6] Japanese patent No. 6505188.

Disclosure of Invention

[ problems to be solved by the invention ]

The burners and burner covers are often made of quartz glass, which is excellent in heat resistance and corrosion resistance. The quartz glass burners are often produced by manually welding circular tubes made of quartz glass, and since the circular tubes themselves made of quartz glass are also produced by adjusting the inner and outer diameters by heating and drawing, the individual burners are likely to have different shapes. Therefore, it is often the case that even if the burner cover is fitted over the burner, reproducibility of the position of the burner cover cannot be obtained. Specifically, the burner housing is not fixed to a specific position of the burner, and sometimes is inserted too deeply, and sometimes conversely, is inserted only to a near front position. Therefore, the state of the flame of the burner is different between individual burners, and the shape of the glass particle deposition body is likely to be different.

Further, in the process of producing the glass particle deposit, there is a problem that the burner cover is displaced from a specific position when the burner position or angle is changed (see documents 5 and 6).

In the burner described in document 1, although the burner cover is fixed to the burner by a fixing material such as teflon tape, the fixing material cannot support the burner cover, and the position of the burner cover is displaced when the glass particle deposition body is repeatedly manufactured, which makes it difficult to obtain reproducibility of the flame state.

In the burner described in document 2, the burner cover is fixed to the burner by winding the heat-resistant tape around the outermost tube of the burner so that the diameter of the heat-resistant tape is the same as the inner diameter of the burner cover, and then the burner cover is attached thereto, and then winding the fixing tape so that the base of the attached burner cover and the exposed portion of the heat-resistant tape wound around the burner are covered with the fixing tape.

In the burner described in document 3, a joint made of heat-resistant resin for connecting nozzles is provided at the tip of the burner, but it is difficult to provide a joint between the burners and the nozzles having large individual differences. In addition, the complex joints are heavy and expensive, which leads to a lack of stability of the burner and also to an increase in costs.

In the burner described in document 4, the double-layer cover is provided at the front end of the burner, which not only increases the cost of the outer cover but also complicates the installation method, and further, the burner front end is heavy, which causes the burner to lack stability and also increases the cost.

In view of these problems, the present invention is intended to provide a method for producing a glass particle deposit, which can easily fix a burner cover having a large individual difference to a specific position of a burner, and which can be easily attached and detached without causing positional deviation due to movement of the burner during production or the like.

[ means for solving problems ]

One embodiment of the present invention is a method for manufacturing a glass fine particle deposit, which is intended to solve the above-described problems, and comprises providing a starting rod and a burner in a reaction vessel, introducing a glass raw material into the burner, causing the glass raw material to undergo a flame hydrolysis reaction in a flame formed by the burner to generate glass fine particles, and depositing the generated glass fine particles on the starting rod to manufacture a glass fine particle deposit; the method for producing a glass fine particle deposited body includes: the burner cover is fixed to the burner by providing a fixing aid around the outermost tube of the burner, inserting a burner cover from the front end of the outermost tube of the burner, and compressing a part of the fixing aid by sandwiching the burner cover and the outermost tube of the burner, and further, the outer diameter of a part of the fixing aid that is not compressed is larger than the inner diameter of a part of the burner cover inserted to the front end of the outermost tube of the burner.

In addition, the fixing aid preferably includes at least one of PTFE (Polytetrafluoroethylene), PFA (Perfluoroalkoxy alkane), and polyimide, and may be provided by winding a tape or a film around the outer circumference of the outermost tube of the burner.

When the burner cover is fixed to the burner, the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner in a cross section perpendicular to the burner longitudinal direction may be 0.5mm to 4mm, and the protrusion distance of the tip of the burner cover from the tip of the burner is preferably 20mm to 40 mm.

A burner according to another embodiment of the present invention includes: a multi-tube burner; a burner housing; and a fixing aid provided on an outer periphery of an outermost tube of the multi-tube burner, and a part of which is sandwiched between the burner cover and the multi-tube burner and compressed, thereby fixing the burner cover to the multi-tube burner; an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of a portion of the burner housing.

[ Effect of the invention ]

According to the present invention, even in a burner having a large individual difference in shape, the burner cover can be easily installed at a specific position of the burner by compressing a part of the fixing aid by being sandwiched between the burner cover and the outermost pipe of the burner. If the fixing aid is formed by winding a sealing tape around the outer periphery of the outermost pipe of the burner for a plurality of times, for example, individual differences between the burner and the burner cover can be absorbed very easily and economically, the burner cover can be firmly set at a specific position, and the burner cover can be prevented from being displaced and dropped during manufacture. Further, the replacement of the burner cover, the attachment and detachment accompanying the replacement, the fine adjustment of the individual burner, and the like are also facilitated, and the time required for the adjustment work can be shortened.

Drawings

Fig. 1 is a schematic view showing a state in which a combustor cover is provided to a combustor via a fixing aid according to an embodiment, wherein a left side view shows a state before the combustor cover is attached, and a right side view shows the state after the combustor cover is attached.

Fig. 2 is a schematic view showing a state in which a combustor cover is provided to a combustor via a compressible auxiliary, the left side of which shows a state before the combustor cover is attached, and the right side of which shows a state after the combustor cover is attached.

FIG. 3 is a schematic configuration diagram showing a manufacturing apparatus for a glass particle deposit with a change in burner angle.

FIG. 4 is a schematic configuration diagram showing a manufacturing apparatus for a glass particle deposit with movement of a burner.

[ description of reference numerals ]

1 burner

2 burner outer cover

3 fixed assistive device

4 glass fine particle deposition body

5 starting lever

6 reaction vessel

7 burner

8 glass fine particles

9 burner for cladding deposition

10 burner housing

Detailed Description

Hereinafter, an example of an embodiment of a method for producing a glass particle deposited body will be described based on the attached drawings. The present invention is not limited to the embodiments described below.

Fig. 1 is a structural diagram of a burner for producing a glass particle deposit according to the present embodiment, wherein the left side shows a state before a burner cover is attached to the burner, and the right side shows a state after the burner cover is attached.

The multi-tube burner 1 is provided with a fixing aid 3 at its outermost tube, and the burner housing 2 is fixed to the burner 1 via the fixing aid 3. Here, gaseous SiCl as a glass raw material gas is accommodated in the multi-tube burner 1₄H as a flame forming gas₂Or O₂Etc. as burner seal gas N₂Or piping of inert gas such as Ar, but not shown.

The glass raw material introduced into the burner is subjected to flame hydrolysis reaction in the flame formed by the burner to produce glass particles, and the glass particles thus produced are deposited on the actuating rod to produce a glass particle deposited body. In this case, it is known that a burner cover is fitted over the tip of the burner in order to prevent glass particles from adhering to the tip of the burner, prevent the tip of the burner from deteriorating and changing its shape, and control the flow of the burner flame.

However, in particular, the quartz glass burner and the burner cover are complicated in structure and difficult to manufacture, and are often manufactured by a single person, so that the individual differences in shape are large in many cases. Therefore, it is difficult to fix the burner cover to a specific position of the burner, and it is difficult to replace the burner cover by attaching and detaching the burner cover.

If the difference in the outer diameters of the burner and the burner cover is large, for example, the distance of projection of the burner cover from the tip of the burner varies depending on the burner, and this affects the flow of the formed flame and the state of deposition of glass particles, thereby deteriorating the shape of the glass particle deposition body and the deposition efficiency. Further, the burner cover is shaken during the deposition of the glass particle deposition body, and adversely affects the flow of the flame or causes breakage. In particular, when the burner angle is changed or the burner position is moved during the deposition to produce the glass particle deposition body, the influence is easily caused.

In order to solve the above-described problems, the present embodiment is configured as follows as shown in fig. 1: a fixing aid 3 for fixing the burner cover 2 to the burner 1 is provided on the outer periphery of the outermost pipe of the burner 1, and the burner cover 2 is provided at the front end of the burner 1 via the fixing aid; and the burner housing 2 is fixed to the burner 1 by compressing a part of the fixing aid in a state of being sandwiched between the burner housing 2 and the outermost tube of the burner 1; further, in the present embodiment, the outer diameter of a part of the uncompressed fixing aid is larger than the inner diameter of the lower part of the burner housing 2. Thereby, the burner housing 2 is always firmly fixed at a specific position of the burner 1.

The material of the fixing aid 3 is not particularly limited, and may be a viscous gel-like material or the like in addition to a solid material, but is preferably a material that is not easily affected by heat or reaction gas generated by a flame emitted from a burner. For example, NITOFLON tape (trade name, manufactured by NITTON electrician) or Walca sealing tape #20 (trade name, manufactured by Walca).

The fixing aid 3 is preferably a tape or a film made of polyimide, PFA (fluororesin), or PTFE (teflon resin) having excellent heat resistance and chemical resistance, and is wound around the outer periphery of the outermost tube of the burner 1 to obtain a good effect. The wallka sealing tape is made of PTFE (teflon resin) or the like, has excellent heat resistance and chemical resistance, is easy to process, is stretchable, and is inexpensive, and can be suitably used in the present embodiment.

The inner diameter of the burner housing 2 is designed to be slightly larger than the outer diameter of the outermost tube of the burner 1 so as not to be affected by the difference in shape of each of the burner 1 and the burner housing 2, and as shown in fig. 2, the tape or film is wound as a fixing aid 3 at a position where the housing is desired to be provided on the outer periphery of the outermost tube of the burner 1, and thereafter, the burner housing 2 is inserted so as to be sandwiched between the burner housing and the outermost tube of the burner 1, and is provided so as to be compressed by the margin of collapse thereof, whereby the burner housing 2 can be easily fixed at a specific position.

At this time, if the burner housing 2 is pushed into the fixing aid by hand with a slow screw, the fixing aid having an outer diameter larger than the inner diameter of the lower end of the burner housing 2 can be set while being collapsed and compressed. At this time, the burner cover 2 is fixed to the outermost pipe of the burner 1 via the fixing aid, and the burner cover 2 does not directly contact the burner 1, so that the fixed state is not easily affected even if there is a difference in the shape of the burner 1 and the burner cover 2. In addition, the combustor cover 2 is fixed to the combustor 1 mainly by a restoring force with which the compressed portion of the fixing aid is restored to the radially outer side. Even if the inner diameter of the burner cover 2 differs from the outer diameter of the outermost pipe of the burner 1, the number of turns of the band serving as the fixing aid can be changed to allow easy adjustment. In addition, there are the following advantages: it is not necessary to prepare a dedicated fixture, maintenance such as replacement is easy, and it is not necessary to finely design the burner 1 and the burner cover 2. Further, by providing the fixing aid 3 in advance such that the outer diameter of an uncompressed portion of the fixing aid is larger than the outer diameter of the outermost pipe at the lower end of the burner housing 2, the burner housing 2 can be fixed at a specific position, and further, the burner housing 2 can be prevented from being displaced downward and falling due to vibration or the like during repeated manufacturing, and flame stability can be ensured even when the burner housing is continuously used.

The fixing aid 3 may be a resin molded article having elasticity and previously molded into a cylindrical shape, instead of a tape or a film. In this case, since the fixing aid 3 has elasticity, the fixing aid 3 can be also spread and fitted around the outer periphery of the outermost tube of the combustor 1.

The outer diameter of the fixing aid 3 on the front end side of the burner 1 is preferably smaller than the outer diameter on the side opposite to the front end. In the embodiment shown in fig. 1 and 2, a step 3a is provided between the two. By pressing the end surface of the burner cover 2 on the side opposite to the burner 1 until the end surface abuts against the step 3a, the burner cover 2 can be fixed at a specific position in the longitudinal direction. In other words, the step 3a functions as an abutting portion.

Instead of providing a step, the fixing aid can also be provided, for example, in the form of a cone. In this case, the outer diameter of the fixing aid 3 may be a shape gradually increasing from the front end side of the burner 1 along the longitudinal direction.

Alternatively, the outer diameter of the main body portion of the fixing aid 3 may be made constant in the length direction, that is, provided in a cylindrical shape, and a protrusion protruding more in the radial direction than the inner diameter of the burner housing 2 from the main body portion may be provided. In this case, the burner cover 2 can be fixed at a specific position in the longitudinal direction by pressing the burner cover 2 until the burner cover abuts against the projection. In other words, the protrusion functions as an abutting portion.

[ examples ]

Fig. 3 is a schematic configuration diagram showing a manufacturing apparatus of a glass particle deposition body with a change in burner angle, and it is effective to provide a fixing aid of the present embodiment to a cladding deposition burner mainly used for cladding deposition.

Fig. 4 is a schematic configuration diagram showing a manufacturing apparatus of a glass particle deposition body with movement of a burner, and it is effective to provide a fixing aid of the present embodiment in the burner 7.

In this example, the glass fine particles were deposited, that is, the glass fine particle deposited body was produced by the OVD method using the production apparatus shown in fig. 4.

A starter rod 5, which was formed by welding dummy quartz rods to both ends of a core member for a single-mode optical fiber having a diameter of 35mm and a length of 1400mm and having a refractive index adjusted to a single-mode optical fiber, was set in a reaction vessel 6 and rotated at 40rpm by a core member rotating motor of a rotating mechanism not shown.

Next, oxygen gas as a flame forming gas, hydrogen gas at 190l/min, and oxygen gas as a carrier gas at 12l/min were supplied to the burner 7 from a gas supply device not shown, and at the same time, SiCl as a raw material gas was supplied at 45g/min₄. The burner 7 was reciprocated at a speed of 150mm/min in the range of 1800mm along the starting rod 5 by a burner traverse motor not shown, and SiCl was used₄The glass fine particles 8 generated by the flame hydrolysis of (3) were deposited around the starter rod 5, and after 30 hours, the glass fine particle deposited body 4 having an outer diameter of 150mm phi and a total weight of 30kg was produced.

Comparative example 1

In comparative example 1, in the production of the glass fine particle deposited body 4, a burner cover fixing aid was not used, but the burner cover was directly placed on the burner and fixed by an adhesive aluminum tape. Here, the burner is a glass multi-tube burner having a straight body portion of 40cm in length, and has oxygen gas and hydrogen gas as flame forming gas, oxygen gas as carrier gas, and SiCl as raw material gas at the root portion₄A flow-through branch pipe. The burner cover is a cylindrical glass having a straight body length of 40 cm. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 1.5mm, and the protrusion distance of the tip end of the burner cover from the tip end of the burner was 30 mm.

In the following embodiments, the same device is used as the burner and the burner cover.

The inner diameter of the burner cover was measured at 5cm intervals in the longitudinal direction by an inner diameter measuring instrument 141 series manufactured by Mitutoyo (Mitutoyo), and the outer diameter of the outermost tube of the burner was measured at 5cm intervals in the longitudinal direction by a vernier caliper 500 series manufactured by Mitutoyo. Hereinafter, the inner diameter and the outer diameter are also measured in the same manner.

[ example 1]

In example 1, in the production of the glass particle deposition body 4, a fastening aid having a thickness of 0.3mm was provided by winding a wallka seal tape (#20) (having a thickness of 0.15mm and a width of 20mm, containing PTFE) around the outer periphery of the outermost tube of the burner for about 2 cycles, and the burner cover was inserted into the fastening aid at a position of 10mm on the burner tip side, and the fastening aid was sandwiched between the burner cover and the outer periphery of the outermost tube of the burner and compressed, thereby attaching the burner cover to the burner via the fastening aid. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 0.2mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 2]

In example 2, a fastening aid having a thickness of 0.75mm was provided by winding a wallka seal tape (#20) (having a thickness of 0.15mm and a width of 20mm, and containing PTFE) around the outer periphery of the outermost tube of the burner for about 5 cycles, and the burner cover was attached to the burner in the same manner as in example 1. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 0.5mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 3]

In example 3, a fastening aid having a thickness of 1.5mm was provided by winding a wallka seal tape (#20) (having a thickness of 0.15mm and a width of 20mm, and containing PTFE) around the outer periphery of the outermost tube of the burner for about 10 cycles, and the burner cover was attached to the burner in the same manner as in example 1. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 1.3mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 4]

In example 4, a fastening aid having a thickness of 4.5mm was provided by winding a wallka seal tape (#20) (having a thickness of 0.15mm and a width of 20mm, and containing PTFE) around the outer periphery of the outermost tube of the burner for about 30 cycles, and the burner cover was attached to the burner in the same manner as in example 1. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 4mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 5]

In example 5, a fastening aid having a thickness of 5mm was wound around the outer periphery of the outermost tube of the burner for about 33 cycles of a wallka seal tape (#20) (0.15 mm in thickness, 20mm in width, containing PTFE), and the burner cover was attached to the burner via the fastening aid in the same manner as in example 1. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 4.7mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 6]

In example 6, a fastening aid having a thickness of 1.5mm was wound around the outer periphery of the outermost tube of the burner by a walca sealing tape (#20) (having a thickness of 0.15mm and a width of 20mm and containing PTFE) for about 10 cycles, and the burner cover was inserted into the fastening aid at a position of 10mm on the burner tip side, and the fastening aid was sandwiched between the burner cover and the outer periphery of the outermost tube of the burner and compressed, thereby attaching the burner cover to the burner via the fastening aid. At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 1.3mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 15 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 7]

In example 7, the burner cover was attached to the burner via the fixing aid in the same manner as in example 6 except that the protruding distance of the tip end of the burner cover from the tip end of the burner was set to 20 mm.

The minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner is 1.3mm, and the outer diameter of a part of the uncompressed fastening aid is larger than the inner diameter of the outermost pipe at the lower end of the burner cover.

[ example 8]

In example 8, the burner cover was attached to the burner via the fixing aid in the same manner as in example 6 except that the protruding distance of the cover front end of the burner from the front end of the burner was set to 40 mm.

The minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner is 1.3mm, and the outer diameter of a part of the uncompressed fastening aid is larger than the inner diameter of the outermost pipe at the lower end of the burner cover.

[ example 9]

In example 9, the burner cover was attached to the burner via the fixing aid in the same manner as in example 6 except that the protruding distance of the tip end of the burner cover from the tip end of the burner was set to 45 mm.

The minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner is 1.3mm, and the outer diameter of a part of the uncompressed fastening aid is larger than the inner diameter of the outermost pipe at the lower end of the burner cover.

[ example 10]

In example 10, a fixing aid having a thickness of 1.5mm was wound around the outer periphery of the outermost tube of the burner by a polyimide film (API-114AFR) (having a thickness of 0.06mm and a width of 25mm and containing polyimide) for about 25 cycles, and the burner cover was inserted into the fixing aid at a position of 10mm on the burner tip side, and the burner cover was sandwiched between the burner cover and the outer periphery of the outermost tube of the burner and compressed, thereby attaching the burner cover to the burner via the fixing aid.

At this time, the minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 1.3mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm.

In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 11]

In example 11, a burner cover was attached to a burner via a fixing aid in the same manner as in example 10 except that a PFA film (AFA-113A) (0.10 mm in thickness, 50mm in width, and containing PFA) was wound around the outer periphery of the outermost tube of the burner for about 15 weeks and the thickness of the fixing aid was set to 1.5 mm.

The minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 1.3mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

[ example 12]

In example 12, a burner cover was attached to a burner via a fixing aid in the same manner as in example 10 except that a polyethylene film (AUE-112B) (0.18 mm in thickness, 25mm in width, containing polyethylene) was wound for about 8 weeks and the thickness of the fixing aid was set to 1.5 mm.

The minimum value of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner was 1.3mm, and the protrusion distance of the tip of the burner cover from the tip of the burner was 30 mm. In addition, an outer diameter of a portion of the fixing aid that is not compressed is larger than an inner diameter of an outermost pipe at a lower end of the burner housing.

In the configurations of comparative example 1 and examples 1 to 12, the change in the outer diameter of the glass particle deposit, the amount of coal deposited on the burner tip, and the damage to the burner after 5 batches of production of the glass particle deposit were examined. The results are shown in table 1.

[ Table 1]

As is clear from comparison of examples 1, 2, 3, 4, and 5, when the burner cover is fixed to the burner, the minimum value (mm) of the difference between the inner diameter of the burner cover and the outer diameter of the outermost pipe of the burner in the cross section perpendicular to the longitudinal direction of the burner is preferably 0.5mm to 4 mm. If this value is less than 0.5mm, it is difficult to provide the burner cover to the burner, and in mass production, the burner cover and the burner may come into contact with each other due to vibration during movement of the burner, which may cause breakage of the burner, which is not preferable.

Further, if the value exceeds 4mm, it is difficult to install the burner cover in the burner, and the flame from the burner excessively spreads, and the distribution of the glass particles in the flame largely varies, resulting in an increase in diameter variation of the glass particle deposit.

As is clear from comparison of examples 3, 6, 7, 8 and 9, the protruding distance of the tip of the burner cover from the tip of the burner is preferably 20mm to 40 mm. If the value is less than 20mm, the effect of reducing the amount of coal adhering to the burner by the burner cover is reduced, coal adheres to the burner itself, the flow of flame is suppressed, and the diameter variation of the glass particle deposit is increased. If the value exceeds 40mm, the flame from the burner is excessively reduced, and the temperature of the portion where the flame contacts locally increases excessively, resulting in an increase in the diameter variation of the glass particle deposit.

In the comparative examples and examples 1, 10, 11 and 12, the material of the fixing aid contains at least one of PTFE, PFA and polyimide, and thus the fixing aid can be used in the present inventionBreakage of the burner can be suppressed. The damage of the burner is caused by deterioration of the fixing aid, deviation and falling of the burner cover from the burner, and the like. By using SiCl₄Since the inside of the chamber is a hydrochloric acid atmosphere as the raw material gas, it is possible to suppress deterioration of the fixing aid by using a member having excellent heat resistance and chemical resistance as the fixing aid.

The present invention is not limited to the above-described embodiments, and can be freely modified and improved as appropriate.