JP2002338256A - Method and apparatus for manufacturing glass particulate deposit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass particulate deposit which is capable of decreasing the tapered segments formed at an end, and an apparatus for the same. SOLUTION: The method for manufactures the glass particulate deposit by moving a rotating glass rod 1 and a plurality of glass particulate-synthesizing burners 8 and 9 relatively back and forth in parallel and depositing the glass particulates (soot) 6 on the surface of the glass rod while moving the turn back position of traversing in a specified direction is characterized in that the deposition of the soot is performed in the state of inclining the burners at both ends to the burner side on the inner side adjacent thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a glass particle deposit body for depositing glass particles in a radial direction on a glass rod while relatively moving a glass rod and a burner for synthesizing glass particles, and an apparatus therefor. ,
In particular, the present invention relates to a method of manufacturing a porous glass base material that can obtain a porous glass base material having a small number of tapered portions formed at both ends of a glass fine particle deposit, and an apparatus therefor.

[0002]

2. Description of the Related Art As a method of manufacturing a large-sized optical fiber preform at a high speed, a plurality of burners 7 for synthesizing glass fine particles are arranged at regular intervals in opposition to a glass rod 1 in a container 4 as shown in FIG. The row of the rotating glass rod 1 and the burner 7 are relatively reciprocated (in the figure, an example is shown in which the glass rod 1 is reciprocated up and down), and fine glass particles (soot) are deposited on the surface of the glass rod 1. There is a method of obtaining a glass fine particle deposit (soot body) 6 by depositing in a layered manner (multilayer soot attachment).

In such a method for depositing fine glass particles (soot attachment method), the variation in outer diameter in the longitudinal direction of the fine glass particle deposit 6 is reduced from the viewpoint of quality improvement, and the fine glass particle deposit 6 is reduced from the viewpoint of productivity. The main issues are to reduce the length of the tapered portion (ineffective portion) formed at the end of the substrate as much as possible and to increase the deposition efficiency, and various methods have been proposed. For example, the start position of the traverse is moved for each relative movement (traverse) between the glass rod and the burner, and after moving to a predetermined position, the traverse is moved in the opposite direction to return to the first traverse start position. Dispersion of the variation of how to hit the glass particle deposit such as the traverse end or burner flame where the sooting time is longer is dispersed throughout the glass particle deposit, There has been proposed a method of reducing the outer diameter fluctuation by equalizing the atmosphere to equalize the deposition amount of the glass fine particles in the longitudinal direction (Japanese Patent No. 2612949).

[0004] When each burner is located in the middle area except for the end area of the traverse, the burners are held at a fixed interval and in a fixed direction. When each burner is located in the end area of the traverse, the outermost burner is located. By inclining at least one or more burners including the second burner in the direction of the outermost burner without moving the second burner, the glass particles are intensively sprayed and deposited on the end side of the porous glass layer, A method of shortening the tapered portions generated at both ends of the glass layer has also been proposed (Japanese Patent Laid-Open No. Hei 5-
221660 publication).

The method disclosed in Japanese Patent No. 2612949 has an effect of reducing the variation in the outer diameter of the glass fine particle deposit in the longitudinal direction. However, since the folding position of the traverse is moved, the glass synthesized by the burner at the end is used. There is a problem that the region where the fine particles are deposited becomes longer, and as a result, the length of the tapered portion becomes longer. Also, Japanese Patent Application Laid-Open No.
According to the method disclosed in Japanese Patent Application Publication No. 60-260, when the burner is directed outward in the end region of the traverse, the amount of glass fine particles deposited on that portion is reduced, and the outer diameter fluctuates in that portion. Furthermore, since this method moves each burner over substantially the entire length of the glass fine particle deposit, increasing the number of burners increases the length of the end portion, so that the effective portion of the glass fine particle deposit does not become longer, thereby improving productivity. Can not hope.

[0006]

SUMMARY OF THE INVENTION The present invention solves such a problem in the prior art, and can shorten the tapered portion formed at the end of the glass fine particle deposit.
In addition, it is an object of the present invention to provide a method for producing a glass particle deposited body capable of efficiently depositing glass particles at a high synthesis rate, and an apparatus therefor.

[0007]

According to the present invention, as means for solving the above problems, the following constitutions (1) to (7) are employed. (1) A plurality of burners for synthesizing glass microparticles are arranged in opposition to a rotating glass rod, and the glass rod and the burner for synthesizing glass microparticles are relatively reciprocated in parallel, and the traverse turning position is determined by the burner interval. Is moved in a fixed direction by a fraction of an integer, and when the turn-back position is moved by the distance of the burner, it is moved in the opposite direction, and this operation is sequentially repeated, so that the glass fine particles synthesized by the burner are put on the surface of the glass rod. A method for producing a glass fine particle deposit by sequentially depositing glass fine particles, wherein the glass fine particles are deposited while the burners at both ends are inclined toward a burner adjacent to them. (2) The method according to (1), wherein the angle between the center line of the burner at each end and the center line of the glass rod is set to 30 ° to 75 °. (3) The method according to (1) or (2), wherein an interval between the burners at both ends and a burner adjacent thereto is set to be larger than an interval between intermediate burners other than the burners at both ends. A method for producing a glass particle deposit.

(4) The distance between the point at which the center lines of the burners at both ends intersect the glass particle deposition surface and the point at which the center lines of the burners adjacent to the burners at both ends intersect with the glass particle deposition surface are different from those at both ends. Wherein the center line of the intermediate burner is set to be equal to the distance between points where the center line intersects the glass particle deposition surface.

(5) A plurality of burners for synthesizing glass particles are arranged in opposition to the rotating glass rod, and the glass rod and the burner for synthesizing glass particles are relatively reciprocated in parallel and synthesized by the burner. An apparatus for manufacturing a glass fine particle deposit by sequentially depositing glass fine particles to be formed on the surface of a glass rod, wherein the burners at both ends are arranged in a state inclined to the burner side adjacent to them. Equipment for manufacturing glass particle deposits. (6) The apparatus for producing a glass fine particle deposit according to the above (5), wherein the burners at both ends are attached so as to be able to adjust the angle with respect to the glass rod arbitrarily. (7) The apparatus for producing a glass fine particle deposit according to the above (5) or (6), wherein the burners at both ends are attached so as to be able to arbitrarily adjust a distance between the burners adjacent to the burners.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A plurality of burners are arranged, and while being reciprocated (traverse) relative to a target rod (glass rod), the turning position of the traverse is moved by a fixed amount, and the moving width is substantially equal to that of the burner. In the method for manufacturing a glass fine particle deposit body that repeats a pattern in which the turning position is sequentially moved in the opposite direction after moving by an amount corresponding to the interval, the moving width is approximately the interval of the burner, so it is theoretically the burner interval. The outer diameter unsteady portion (tapered portion) should be generated. However, since the glass fine particles synthesized by the second and subsequent burners from the outside also flow in the inclined direction of the tapered portion, the length of the tapered portion (tapered portion) Length) is considerably longer than the interval between the burners.

According to the present invention, in the above-mentioned method, the glass fine particles flow toward the end by depositing the glass fine particles in a state where the burners located at both ends in the relative movement direction are inclined toward the burners adjacent to them. And the taper length formed at the end is reduced. Here, to incline the burners at both ends to the side of the burner adjacent to them means to incline so that the angle between the burner and the inclined surface of the tapered portion approaches 90 °. FIG. 1 schematically shows the state of deposition of glass particles by each burner. In the prior art, FIG.
As shown in (a), the end burner 8 and the other intermediate burners 9 are both the center line of the burner and the glass rod 1.
Is 90 ° (corresponding to θ in FIG. 1).
The glass fine particles ejected from the end burners 8 located at both ends are gradually increased in the taper portion 2 as the outer diameter of the glass fine particle deposit (soot body 6) increases (see FIG. 1).
(The direction of the white arrow in (a)).

Here, the shape of the end of the soot body 6 can be changed by inclining the end burner 8 toward the adjacent intermediate burner 9, that is, making θ in FIG. 1 smaller than 90 °. If the degree of inclination of the end burner 8 is too large, the taper length will be lengthened rather. Therefore, it is necessary to set an appropriate angle in accordance with manufacturing conditions. FIG. 1B shows the deposited shape of the glass particles ejected from each burner when the inclination angle of the end burner 8 is changed, and FIG. 1C shows the shape of the tapered portion at that time.

Also, the taper length can be adjusted by changing the amount of glass particles deposited, and when the angle is small, the glass raw material, flammable gas, oxygen gas, and seal gas to be supplied to the burners located at both ends. By reducing the supply amount of at least one of the above, and conversely, under conditions where the angle is large, the taper length can be shortened by increasing the gas flow rate.

According to the results of the study by the present inventors, the state of the tapered portion of the glass fine particle deposition becomes the longest when the end burner is at 90 ° with respect to the target rod (glass rod). It was confirmed that the length became shorter. That is, when the supply amount of the glass raw material is constant, the effect of reducing the taper length is large when the burner angle (θ) is in the range of 30 ° to 75 °. When the burner angle exceeds 75 °, the effect of reducing the taper length decreases, and
At 5 °, soot deposition efficiency decreases and the taper length increases,
At 15 ° to 30 °, although the taper length was reduced, flame interference with adjacent burners occurred, and it was found that the soot body outer diameter at that portion increased. In this regard, by reducing the amount of the raw material for synthesizing glass particles supplied to the portion, the deposition efficiency can be reduced and the soot body shape can be stabilized.

As shown in FIG. 2A, the end burner 8
The end burner 8 is maintained with the distance a ₁ between the intermediate burner 9 and the adjacent intermediate burner 9 being the same as the distance b ₁ between the intermediate burners 9.
Is inclined toward the intermediate burner 9, a portion having a large outer diameter may be formed between the constant outer diameter portion and the tapered portion of the soot body 6 as described above. In this case, in addition to the method of reducing the supply amount of the glass raw material to the end burner 8, FIG.
The distance a ₂ between the point at which the center line of the end burner 8 intersects the glass particle deposition surface and the point at which the center line of the intermediate burner 9 adjacent to the end burner 8 intersects the glass particle deposition surface, as shown in FIG. by the center line of the middle burner 9 except parts burners 8 is set to be equal to the distance b ₂ of each other point of intersection with the glass particle deposition surface, it is possible to restrain the outer diameter becomes thicker.

The angle of inclination of the end burner and the size of the interval between the end burner and the intermediate burner adjacent to the end burner may be appropriately set according to the characteristics of the burner, the conditions for depositing the glass particles, and the like. For adjustment of the inclination angle and interval of the burner, a device in which the burner is set at a predetermined angle and interval in advance may be used, but a mechanism that arbitrarily adjusts the inclination angle at the end burners at both ends and an adjacent intermediate burner and It is convenient to use a device having a function that can arbitrarily set the interval between the images.

[0017]

EXAMPLES Hereinafter, the method of the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. (Example 1) Glass rod (core part has a diameter of 25
(mm, length: 750 mm), six burners were arranged at an interval of 150 mm, and glass particles were deposited by a method in which a starting rod was reciprocated up and down. To each burner, silicon tetrachloride: 3 L / min, hydrogen: 40 L / min, oxygen: 50 L / min, and argon: 5 L / min were supplied under the same conditions. The traverse distance is set to the burner interval. The traverse turning position is shifted by 25 mm, and when the traverse is shifted by the burner interval, the turning position is changed in the opposite direction. (Part) was 170 mm.

The angle of inclination of the burners at both ends is 10 ° to 5 °.
Glass fine particle deposits were manufactured at different degrees, and the relationship between the inclination angle and the length of the tapered portions formed at both ends was examined.
The results are as shown in FIG. 4. In order to achieve an increase in the synthesis speed and a reduction in the taper length, a condition in which the angle of inclination (θ) of both end burners to the intermediate burner is in the range of 30 ° to 75 ° is suitable. You can see that it is. Note that, in this example, the length of the constant outer diameter portion was substantially the same.

[0019]

According to the present invention, a plurality of burners for synthesizing glass fine particles are arranged to face a rotating glass rod, and the glass rod and the burner for synthesizing glass fine particles are relatively reciprocated in parallel. The turning position of the traverse is moved in a fixed direction by a fraction of an integer of the burner interval, and the turning position is moved in the reverse direction when the turning position has moved by the burner interval. Solves the problem of increasing the number of tapered portions at both ends of a glass fine particle deposit, which occurs in a method of manufacturing a glass fine particle deposit by sequentially depositing glass fine particles on the surface of a glass rod, and depositing glass fine particles having a short tapered portion at both ends. A method of manufacturing a body and an apparatus therefor are provided.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a state of deposition of glass particles by an end burner and other intermediate burners.

FIG. 2 is a view for explaining a relationship between an interval between an end burner and an adjacent intermediate burner and a shape of a glass fine particle deposit near a tapered portion.

FIG. 3 is an explanatory view showing an outline of production of a glass particle deposit by a method of depositing multilayer glass particles.

FIG. 4 is a diagram showing a relationship between an inclination angle of an end burner and lengths of tapered portions formed at both ends in the first embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Glass rod 2 Tapered part 4 Container 5
Exhaust port 6 Glass particle deposit (soot body) 7 Burner 8 End burner 9 Intermediate burner

Claims (7)

[Claims] 1. A plurality of burners for synthesizing glass fine particles are arranged to face a rotating glass rod, and the glass rod and the burner for synthesizing glass fine particles are relatively reciprocated in parallel with each other, so that the traverse folding position is determined. The burner interval is moved in a fixed direction by a substantially integral number, and when the turning position is moved by the distance of the burner, it is moved in the opposite direction. In a method of manufacturing a glass fine particle deposit by sequentially depositing on the surface,
A method for producing a glass fine particle deposit, wherein glass fine particles are deposited in a state in which burners at both ends are inclined toward a burner adjacent to them. 2. The glass fine particle deposit according to claim 1, wherein an angle between a center line of the burners at both ends and a center line of the glass rod is set to 30 ° to 75 °. Production method. 3. The method according to claim 1, wherein an interval between the burners at both ends and a burner adjacent thereto is set to be larger than an interval between intermediate burners other than the burners at both ends. Method for producing a glass fine particle deposit. 4. The distance between the point at which the center line of the burners at both ends intersects the glass particle deposition surface and the point at which the center line of the burners adjacent to the burners at both ends intersects the glass particle deposition surface is different from that at both ends. The method according to claim 3, wherein the intermediate burner is set so as to have a distance between points where the center line of the intermediate burner intersects the glass particle deposition surface. 5. A plurality of burners for synthesizing glass fine particles are arranged in opposition to a rotating glass rod, and the glass rod and the burner for synthesizing glass fine particles are relatively reciprocated in parallel to be synthesized by the burner. For depositing glass fine particles sequentially on the surface of a glass rod to produce a glass fine particle deposit body, wherein the burners at both ends are arranged in a state inclined to the burner side adjacent thereto. Production equipment for fine particle deposits. 6. The apparatus according to claim 5, wherein the burners at both ends are attached so that the angle with respect to the glass rod can be arbitrarily adjusted. 7. The apparatus for producing a glass particle deposit according to claim 5, wherein the burners located at both ends are attached so that the distance between the burners and the burners adjacent to the burners can be arbitrarily adjusted. .