JP2007106647A - Method for manufacturing deposited body of glass fine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a deposited body of glass fine particle which can manufacture a high quality deposited body of glass fine particle by sufficiently cleaning the surface without softening the starting seed rod. <P>SOLUTION: The method comprises flame washing a starting seed rod 13 by periodically changing the flame temperature through periodically changing the flow rate of at least one of a combustion gas and a supporting gas of the fire polishing burner 16 when manufacturing the deposited body of glass fine particle 15 by depositing the glass fine particle, which is synthesized by hydrolyzing or oxidizing a glass raw material, on the starting seed rod 13 in the flame 14a that is formed by the burner 14. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a glass fine particle deposit by producing glass fine particle deposits by depositing glass fine particles synthesized by hydrolysis or oxidation reaction of glass raw materials in a flame formed by a burner on a starting seed rod. It is.

Conventionally, a flame polishing method is known in which the surface of a glass base material is flame-polished with an oxyhydrogen flame (see, for example, Patent Document 1).
As shown in FIG. 4, in the flame polishing apparatus 100 used in this flame polishing method, a starting seed is provided via a support bar 103 at the lower end of a main bar 102 that is gripped by a rotary chuck 101 so as to be rotatable and vertically movable. A bar 104 is connected. A plurality of flame polishing hydrogen burners 105 are provided around the entire circumference of the starting seed bar 104. Further, a plurality of auxiliary heating oxyhydrogen burners 106 are provided over the entire circumference at a position below the flame polishing oxyhydrogen burner 105.
Therefore, the surface of the glass base material 107 is flame-polished by moving the glass base material 107 rotated by the rotating chuck 101 up and down and moving the flame polishing oxyhydrogen burner 105 relatively in the longitudinal direction.
JP-A-6-247735 (FIG. 1)

By the way, a glass raw material is introduced into a flame, a glass particle is synthesized by hydrolysis reaction or oxidation reaction in the flame, and this is deposited on the surface of the starting seed bar to produce a glass particle deposition base material. For example, in the VAD method (vapor phase shafting method) or the like, if impurities such as dust adhere to the surface of the starting seed bar, there is a possibility that a high-quality glass particulate deposition base material cannot be obtained. For this reason, the surface of the starting seed bar is cleaned by flame polishing before the deposition of the glass fine particles.
However, if the flame polishing is performed at a high temperature, the cleaning ability is improved, but the temperature of the starting seed bar is raised and softened, which may be bent. On the other hand, when flame polishing is performed at a low temperature, there is a possibility that sufficient cleaning cannot be performed.

  An object of the present invention is to provide a method for producing a glass fine particle deposit capable of producing a high-quality glass fine particle deposit by sufficiently cleaning the surface without softening the starting seed bar.

  In order to achieve the above-mentioned object, the first feature of the method for producing a glass fine particle deposit according to the present invention is that glass fine particles synthesized by hydrolysis or oxidation reaction of a glass raw material in a flame formed by a burner are used. A method for producing a glass fine particle deposit by depositing on a starting seed rod, wherein the surface of the starting seed rod is subjected to flame cleaning by periodically changing the flow rate of at least one of combustion gas and auxiliary combustion gas.

  In the method for producing a glass particulate deposit constructed as described above, a glass particulate deposit is obtained by depositing glass particulate synthesized by hydrolysis or oxidation reaction of a glass raw material in a flame formed by a burner on a starting seed rod. In the manufacturing process, the starting seed bar is flame cleaned. At this time, if the flame cleaning is performed at a high temperature, the cleaning ability is further improved, but the starting seed bar is softened and bent, and there is a possibility that a high-quality glass particulate deposit cannot be produced. On the other hand, if the flame temperature is low, there is no concern that the starting seed bar will bend, but cleaning will not be performed well. Therefore, sufficient cleaning can be performed without bending the starting seed bar by periodically changing the flame temperature by periodically changing the flow rate of at least one of the combustion gas and the auxiliary combustion gas. For example, the surface of the starting seed bar can be cleaned cleanly by combining high and low temperatures.

  Moreover, the manufacturing method of the glass fine particle deposit | stacking body concerning this invention exists in carrying out the flame cleaning of the surface of the said starting seed stick | rod, depositing glass particulates on a starting seed stick | rod.

  In the method for producing a glass fine particle deposit body configured in this way, the surface of the starting seed rod is flame-cleaned, and subsequently the glass fine particles are deposited on the surface of the cleaned starting seed rod. It is possible to omit the flame cleaning process performed before the manufacturing process and the deposition of the glass fine particles.

  The method for producing a glass fine particle deposit according to the present invention is to perform flame cleaning so that the surface temperature of the starting seed bar becomes high in the initial stage of depositing the glass fine particles on the starting seed bar.

  In the method for producing a glass fine particle deposit body configured as described above, generally, there is a tendency that foreign matters such as carbon and glass powder tend to adhere to the surface of the starting seed rod in the initial stage of starting the deposition of the glass fine particles. Is known, and can be efficiently cleaned by high-temperature cleaning the seed bar in this initial stage. Since the starting seed bar uses quartz glass with high viscosity, it is difficult to soften even at high temperatures. In addition, if the ineffective portion is washed cleanly, a clean glass particulate deposit is completed.

  Further, the method for producing a glass fine particle deposit according to the present invention is to perform flame cleaning so that the surface temperature of the starting seed rod becomes higher in the latter half compared to the first half of the deposition step in which the glass fine particles are deposited on the starting seed rod. .

  In the method for producing a glass particulate deposit body configured as described above, flame cleaning is performed so that the surface temperature of the starting seed rod becomes higher in the latter half compared to the first half of the deposition step in which the glass particulate is deposited on the starting seed rod. Thus, sufficient cleaning can be performed.

  Further, the method for producing a glass fine particle deposit according to the present invention is such that, when the glass fine particles are deposited on the starting seed rod, the surface temperature of the starting seed rod is increased when the rotational speed or pulling speed of the starting seed rod is increased. Is to change the flow rate pattern of the combustion gas or the auxiliary combustion gas so as to be high.

  In the method for producing a glass particulate deposit constructed as described above, since the surface temperature of the seed rod tends to decrease and the flame cleaning ability decreases as the rotation speed and pulling speed of the seed rod increase, the rotation speed and pulling speed increase. By increasing the surface temperature of the seed bar in response to the increase in speed and increasing the flame cleaning ability, foreign substances can be removed and a clean surface can be obtained.

  According to the present invention, since the flame temperature is periodically changed by periodically changing the flow rate of at least one of the combustion gas and the auxiliary combustion gas, the flame cleaning is performed at a high temperature as in the prior art. The problem that the seed bar softens and bends, and the problem that the flame temperature is low and sufficient cleaning is not performed can be solved, and the effect that sufficient cleaning can be performed without bending the starting seed bar. can get.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an example of a production apparatus for carrying out the method for producing a glass fine particle deposit according to the present invention, FIG. 2 is a graph showing an example of a pattern of periodic changes in hydrogen and oxygen supply flow rates, and FIG. -(C) is a graph which shows the example of a pattern of the other periodic change.

As shown in FIG. 1, an apparatus 10 for producing a glass fine particle deposit for carrying out a VAD method (vapor phase shafting method) which is a first embodiment of a method for producing a glass fine particle deposit according to the present invention comprises a reaction vessel. A rotary pulling device 12 is provided on the chamber 11, and the starting seed bar 13 is suspended in the chamber 11 so as to be rotatable and liftable. The chamber 11 is provided with a burner 14 for depositing glass fine particles to which a silicon compound such as SiCl ₄ as a soot source gas and a fuel gas such as H ₂ and O ₂ are supplied. Glass particulates 15 are manufactured by forming glass particulates by hydrolysis or oxidation reaction of a glass raw material in a flame and depositing them on the outer peripheral surface of the starting seed bar 13. A flame polishing burner 16 for flame polishing the starting seed bar is provided below the burner 14.
The chamber 11 is provided with an exhaust pipe 17 so that the inside of the chamber 11 is exhausted.

The flame polishing burner 16 is provided with a hydrogen mass flow controller 18a for controlling the flow rate of hydrogen (H ₂ ) supplied to the flame polishing burner 16 and an oxygen mass flow controller 18b for controlling the flow rate of oxygen (O ₂ ). It has been.

Next, a method for producing a glass particulate deposit according to the present invention will be described.
This manufacturing method is a method of manufacturing a glass fine particle deposit 15 by depositing glass fine particles synthesized by hydrolysis or oxidation reaction of a glass raw material in a flame 14 a formed by a burner 14 on a starting seed rod 13. The surface of the starting seed bar 13 is subjected to flame cleaning by periodically changing the flow rate of at least one of combustion gas and auxiliary combustion gas.

The flame cleaning is performed by the flame polishing burner 16, and at least one supply amount of oxygen (O ₂ ) as a combustion gas or hydrogen (H ₂ ) as a combustion gas supplied to the flame polishing burner 16 is periodically cycled. Change. This change in the supply amount is performed using the hydrogen mass flow controller 18a or the oxygen mass flow controller 18b. In other words, the polishing power is controlled by adjusting the heating power of the flame polishing burner 16 by controlling either the oxygen supply amount, the hydrogen supply amount, or both.

  It is desirable that the surface of the starting seed bar 13 be flame cleaned while depositing glass particles on the starting seed bar 13. As a result, the surface of the starting seed rod 13 is flame-cleaned, and glass particles are subsequently deposited on the cleaned surface of the starting seed rod 13, so that a separate flame is prepared in advance before the manufacturing process of the starting seed rod 13 and the deposition of the glass particles. The cleaning process can be omitted. Further, the glass fine particles are deposited on the cleaned starting seed rod 13, and a high-quality glass fine particle deposit 15 can be manufactured.

  In addition, in the flame polishing, it is desirable to perform flame cleaning so that the surface temperature of the starting seed bar 13 becomes high in the initial stage of depositing the glass fine particles on the starting seed bar 13. This is because, generally, foreign substances such as carbon and glass powder tend to adhere to the surface of the starting seed bar 13 at the initial stage of starting the deposition of the fine glass particles. This is because cleaning can be performed efficiently. Since the starting seed bar 13 uses quartz glass having a high viscosity, it is difficult to soften even at a high temperature. Further, if the ineffective portion is washed cleanly, a clean glass particulate deposit 15 is completed.

  Further, it is desirable to perform flame cleaning so that the surface temperature of the starting seed bar 13 is higher in the latter half than in the first half of the deposition step in which the glass fine particles are deposited on the starting seed bar 13.

When glass fine particles are deposited on the starting seed rod 13, if the rotation speed or pulling speed of the starting seed rod 13 increases, the combustion gas or auxiliary combustion is performed so that the surface temperature of the starting seed rod 13 can be increased to perform flame cleaning. It is desirable to change the gas flow pattern.
That is, when the rotation speed and the pulling speed of the starting seed bar 13 are increased, the surface temperature of the starting seed bar 13 tends to decrease and the flame cleaning ability tends to decrease. For this reason, the flow rate pattern is changed so as to increase the flow rate of the combustion gas or auxiliary combustion gas to increase the thermal power of the flame polishing burner 16 in response to the increase in the rotational speed and the pulling speed. Thereby, by raising the surface temperature of the starting seed bar 13 and increasing the flame cleaning ability, foreign substances can be removed and a clean surface can be obtained.

FIG. 2 shows a flow rate pattern of the combustion gas or auxiliary combustion gas.
In the pattern shown in FIG. 2, the hydrogen flow rate and the oxygen flow rate are increased or decreased simultaneously in a rectangular pulse shape. That is, the flow rate and duration for raising the surface temperature of the starting seed bar 13 and the flow rate and duration for lowering the temperature of the starting seed bar 13 are alternately arranged at a constant cycle. At this time, as the high temperature, the temperature is set high and the time is set within a range in which the starting seed bar 13 is not softened. In addition, as the low temperature, a temperature and a time at which the surface temperature of the starting seed bar 13 can be maintained so as not to be lower than a predetermined temperature are set.
Note that FIG. 2 shows a case where the flow rate is changed for both hydrogen and oxygen, but it is also possible to make the oxygen constant without changing oxygen.

Further, as shown in FIG. 3A, the change between the high temperature and the low temperature can be changed in a curved line. In FIG. 3A, only the change in the hydrogen supply amount is shown. However, oxygen is the same as in the case described above in FIG. 2, and may be changed in the same manner as hydrogen. Good.
Similarly, as shown in FIG. 3B, it may be changed into a sawtooth shape. Furthermore, as shown in FIG. 3C, the supply time can be changed with the change in the supply amount. Also in this case, the supply amount and time for which the starting seed bar 13 is not bent and the supply amount and time for which the temperature does not fall below the predetermined temperature are the same.

  According to the method for producing a glass fine particle deposit described above, sufficient flame cleaning can be performed without bending the starting seed bar 13 by periodically changing the flame temperature by periodically changing at least one of hydrogen and oxygen. Thus, a high-quality glass fine particle deposit can be produced.

In addition, the manufacturing method of the glass fine particle deposit body of this invention is not limited to embodiment mentioned above, A suitable deformation | transformation, improvement, etc. are possible.
For example, the supply pattern of hydrogen and oxygen shown in the above-described embodiment is merely an example, and the supply amount and time for which the starting seed bar 13 is not bent is changed periodically as the supply amount and time for which the temperature does not fall below a predetermined temperature. Pattern.
In the above-described embodiment, the case where the flame polishing is performed simultaneously with the deposition of the glass fine particles has been described. However, the flame polishing can be performed in advance.
Further, in the manufacturing apparatus 10 described above, a case where one burner 14 and one flame polishing burner 16 are used has been described, but a plurality of burners 14 and 16 may be used.
Further, in the above-described method for manufacturing the glass fine particle deposit, the case where the glass fine particle deposit 15 is formed by depositing the glass fine particles at once while rotating and raising the starting seed bar 13 has been described. On the other hand, glass fine particles can be deposited in multiple layers while the starting seed rod 13 is reciprocated up and down.

Next, specific examples will be described in comparison with comparative examples.
Example 1
A glass particulate deposit 15 was manufactured by the VAD method using the manufacturing apparatus 10 shown in FIG. At this time, the starting seed rod 13 was flame-polished simultaneously with the deposition of the glass fine particles. Therefore, the pre-process for flame polishing the starting seed bar 13 in advance is omitted.
The starting seed bar 13 had a diameter of 25 mm and a lifting speed of 80 mm / hour. The first half of the total length of the starting seed bar 13 is supplied to a flame polishing burner 16 at a hydrogen temperature of 25 liters / minute and oxygen at 10 liters / minute for 20 seconds to form a high temperature part, hydrogen at 10 liters / minute, and oxygen at 7 liters. This was repeated as a low temperature part by supplying for 10 seconds at / min. On the other hand, in the latter half, hydrogen was supplied at 20 liters / minute and oxygen at 10 liters / minute for 15 seconds to supply a high-temperature part, and hydrogen was supplied at 15 liters / minute and oxygen at 7 liters / minute for 10 seconds to form a low-temperature part. Repeated.
As a result, the surface temperature of the starting seed rod 13 varied between 1400 ° C. and 1300 ° C., but the bending of the starting seed rod 13 did not occur. Further, when the base material was manufactured by heating and transparentizing the manufactured glass particulate deposit 15, the number of foreign matters on the surface was five per base material and was very small.

(Comparative Example 1)
Similarly to Example 1, the glass fine particle deposit 15 was produced by the VAD method using the production apparatus 10, and the starting seed rod 13 was flame-polished simultaneously with the deposition of the glass fine particles.
The starting seed bar 13 has a diameter of 25 mm and a pulling speed of 80 mm / hour, which is the same as in the first embodiment. The flame polishing burner 16 was continuously supplied with hydrogen at 20 liters / minute and oxygen at 10 liters / minute.
As a result, the surface temperature of the starting seed bar 13 was equal to the average temperature of Example 1 in which the supply amounts of hydrogen and oxygen were periodically changed, and became 1350 ° C. However, the starting seed bar 13 gradually softened and swayed, and the synthesis and deposition of the glass particles could not be continued.

(Comparative Example 2)
Similarly to Example 1, the glass fine particle deposit 15 was produced by the VAD method using the production apparatus 10, and the starting seed rod 13 was flame-polished simultaneously with the deposition of the glass fine particles.
The starting seed bar 13 has a diameter of 25 mm and a pulling speed of 80 mm / hour, which is the same as in the first embodiment. The flame polishing burner 16 was continuously supplied with hydrogen at 15 liters / minute and oxygen at 7 liters / minute.
As a result, the surface temperature of the starting seed bar 13 is equal to the temperature of the low temperature part of Example 1 in which the supply amounts of hydrogen and oxygen are periodically changed to 1300 ° C., and is equal to the temperature of the low temperature part of Example 1 became. Then, when the base material was manufactured by heating and transparentizing the manufactured glass particulate deposit 15, the number of foreign matters on the surface was 50 per base material, and about 70% of the foreign matters were generated in the first half of the starting seed bar 13. Concentrated on the part.

  As described above, in the method for producing a glass particulate deposit according to the present invention, the flame temperature is periodically changed by periodically changing the flow rate of at least one of the combustion gas and the auxiliary combustion gas. The problem is that the starting seed bar softens and bends because the flame cleaning is hot as before, and the problem that the cleaning is not performed sufficiently because the flame temperature is low can be solved, and the starting seed bar is bent. Glass particulate deposits by depositing glass particulates synthesized by hydrolysis or oxidation reaction of glass raw materials in the flame formed by the burner on the starting seed rod, with the effect that sufficient cleaning can be performed without It is useful as a method for producing a glass fine particle deposit for producing the above.

It is a block diagram which shows the example of the manufacturing apparatus which can implement the manufacturing method of the glass fine particle deposition body which concerns on this invention. It is a graph which shows the typical example of the supply pattern of combustion gas or auxiliary combustion gas. (A)-(C) are the graphs which show the other example of the supply pattern of combustion gas or auxiliary combustion gas. It is a perspective view which shows the conventional flame polishing method.

Explanation of symbols

13 Starting seed bar 14 Burner 14a Flame 15 Glass particulate deposit

Claims (5)

A method of producing a glass particulate deposit by depositing glass particulates synthesized by hydrolysis or oxidation reaction of a glass raw material in a flame formed by a burner on a starting seed rod,
A method for producing a glass particulate deposit, wherein the surface of the starting seed bar is subjected to flame cleaning by periodically changing the flow rate of at least one of combustion gas and auxiliary combustion gas.   2. The method for producing a glass particulate deposit according to claim 1, wherein the surface of the starting seed rod is subjected to flame cleaning while depositing the glass particulate on the starting seed rod.   3. The method for producing a glass particulate deposit according to claim 1 or 2, wherein in the initial stage of depositing the glass particulates on the starting seed rod, flame cleaning is performed such that the surface temperature of the starting seed rod is increased.   The flame cleaning is performed so that the surface temperature of the starting seed bar becomes higher in the latter half compared to the first half of the deposition step in which the glass fine particles are deposited on the starting seed bar. A method for producing a glass particulate deposit.   When depositing glass fine particles on the starting seed rod, if the rotational speed or pulling speed of the starting seed rod increases, the flow pattern of the combustion gas or auxiliary combustion gas is changed so that the surface temperature of the starting seed rod increases. The method for producing a glass fine particle deposit according to any one of claims 1 to 4, wherein:

Images