JP6086168B2 - Method for producing glass particulate deposit and method for producing glass base material - Google Patents

Description

  The present invention is a glass for producing a glass particulate deposit by depositing glass particulates on a starting rod by the OVD method (external method), VAD method (vapor phase axis method), MMD method (multi-burner multilayer method), or the like. The present invention relates to a method for producing a fine particle deposit and a method for producing a glass base material by heating the glass fine particle deposit to make it transparent.

  Conventionally, as a method for producing a glass base material, a deposition process for producing a glass fine particle deposit by an OVD method, a VAD method or the like, and a transparentizing step for heating the glass fine particle deposit to produce a transparent glass base material, The manufacturing method containing this is known.

For example, Patent Document 1 discloses a precision burner that oxidizes a silicon-containing compound that does not contain a halide such as octamethylcyclotetrasiloxane (OMCTS), which is used when forming a preform (glass base material).
Patent Document 2 discloses a linear burner in which a silicon-containing compound such as SiCl ₄ , GeCl _4, or OMCTS is hydrolyzed or oxidized.

Japanese National Patent Publication No. 11-510778 US Pat. No. 6,743,011

  However, in the burners described in Patent Document 1 and Patent Document 2, the glass raw material yield is improved when the glass fine particle deposit is produced by depositing the glass fine particles generated in the flame of the burner on the starting rod. There was room for improvement.

  Therefore, the present invention has been made in view of such problems, and provides a method for producing a glass fine particle deposit and a method for producing a glass base material that can improve the glass raw material yield of the glass fine particle deposit. The purpose is to do.

In order to solve the above problems, the method for producing a glass fine particle deposit according to the present invention comprises:
A starting rod and a glass fine particle production burner are installed in the reaction vessel, glass raw material is introduced into the burner, and glass fine particles are generated by flame pyrolysis reaction in the flame formed by the burner. A method for producing a glass particulate deposit having a deposition step of depositing the glass particulate on the starting rod to produce a glass particulate deposit,
In the deposition step, at least two glass material outlets ejected from the burner are provided per burner, and the area of at least one of the outlets is 2.25 of the area of the flame forming portion of the burner. × 10 ⁻⁴ or less, the glass raw material is supplied to each of the outlets in a liquid state, and the inner periphery of the gas outlet is disposed at a position within 1.0 mm outside of the outer periphery of each of the outlets. Gas is spouted from the exit.

Moreover, the manufacturing method of the glass base material of the present invention includes
A glass fine particle deposit is produced by the above-described method for producing a glass fine particle deposit, and the produced glass fine particle deposit is heated to produce a transparent glass base material.

  According to the method for producing a glass fine particle deposit and the method for producing a glass base material of the present invention, the glass raw material yield of the glass fine particle deposit can be improved.

It is a block diagram which shows one form of the manufacturing apparatus which enforces the manufacturing method of the glass fine particle deposit body concerning this invention. (A) is a top view of the burner surface which shows one form of the burner which produces | generates glass particulates in the manufacturing apparatus shown in FIG. 1, (b) is an enlarged view of the burner surface which shows the raw material port of a burner. It is a partial expanded sectional view of the burner which shows the state which supplied the liquid raw material to the raw material port shown in FIG.2 (b), and supplied the gas from the outer side. It is an enlarged view of the burner surface which shows the raw material port of the burner which concerns on the modification of this invention. It is a top view of the burner surface which shows another form of the burner which produces | generates glass particulates in the manufacturing apparatus shown in FIG.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.
The method for producing a glass particulate deposit according to the present invention comprises:
(1) A starting rod and a glass fine particle producing burner are installed in a reaction vessel, glass raw material is introduced into the burner, and glass fine particles are generated by flame pyrolysis reaction in the flame formed by the burner. And a method for producing a glass particulate deposit having a deposition step of depositing the produced glass particulate on the starting rod to produce a glass particulate deposit,
In the deposition step, at least two glass material outlets ejected from the burner are provided per burner, and the area of at least one of the outlets is 2.25 of the area of the flame forming portion of the burner. × 10 ⁻⁴ or less, the glass raw material is supplied to each of the outlets in a liquid state, and the inner periphery of the gas outlet is disposed at a position within 1.0 mm outside of the outer periphery of each of the outlets. Gas is spouted from the exit.
According to this configuration, it is possible to reduce the amount of the glass raw material injected from each outlet of the glass fine particle generating burner, promote the reaction of the glass raw material, and improve the glass raw material yield of the glass fine particle deposit. be able to. Further, since the glass raw material is supplied in a liquid state, it is not necessary to provide an expensive processing apparatus for vaporizing the glass raw material having a high boiling point, and the manufacturing cost of the glass fine particle deposit can be suppressed. Furthermore, since the gas is ejected from the very vicinity outside the emission port from which the liquid material is ejected, the glass material can be efficiently atomized.

(2) In the deposition step, it is preferable to provide five or more outlets per one burner.
According to this configuration, the glass raw material yield can be further improved by further promoting the reaction of the glass raw material.

(3) In the deposition step, it is preferable that the area of the one emission port is 1.00 × 10 ⁻⁴ or less of the area of the flame forming portion.
According to this configuration, since the glass raw material can be spread in the flame, the reaction of the glass raw material can be promoted.

(4) In the deposition step, it is preferable that the area of the one emission port is 2.50 × 10 ⁻⁵ or less of the area of the flame forming portion.

(5) In the deposition step, it is preferable that an area of the one emission port is 4.00 × 10 ⁻⁶ or less of an area of the flame forming portion.

(6) In the said deposition process, it is preferable to eject the gas containing oxygen gas from each said gas ejection port, and to atomize the said glass raw material ejected from each said ejection port.
According to this structure, the oxidation reaction of a glass raw material can be accelerated | stimulated by ejecting the gas containing oxygen gas from the very vicinity of the emission port outer side of a liquid raw material.

(7) In the deposition step, it is preferable that a gas having a flow velocity of 855 m / s or more is ejected from each gas ejection port to atomize the glass material ejected from each ejection port.
According to this structure, the spray liquid diameter of a glass raw material can be made small, and the vaporization efficiency of the atomized glass raw material can be raised.

  (8) In the deposition step, it is preferable that a gas having a flow velocity of 1283 m / s or more is ejected from each gas ejection port to atomize the glass material ejected from each ejection port.

(9) In the deposition step, it is preferable that the number of oxygen molecules contained in the gas ejected from each gas ejection port is equal to or greater than the number of Si atoms contained in the glass raw material ejected from each emission port.
According to this configuration, the efficiency of oxidizing the glass raw material to SiO ₂ can be increased.

  (10) In the deposition step, the number of oxygen molecules contained in the gas ejected from each gas outlet is 1.5 times or more the number of Si atoms contained in the glass raw material ejected from each outlet. It is preferable to do.

(11) In the deposition step, the glass raw material supplied to the burner is preferably siloxane.
According to this configuration, it is possible to suppress the manufacturing cost of the glass particulate deposit without generating harmful substances such as HCl when producing the glass particulates.

  (12) In the deposition step, it is preferable that the glass raw material supplied to the burner is octamethylcyclotetrasiloxane (OMCTS).

Moreover, the manufacturing method of the glass base material of the present invention includes
(13) A glass fine particle deposit is produced by the method for producing a glass fine particle deposit according to any one of (1) to (12) above, and the produced glass fine particle deposit is heated to produce a transparent glass base material. A transparentizing step.
According to this structure, the manufacturing method of the glass base material which can improve the glass raw material yield of a glass particulate deposit body can be provided.

  (14) It is preferable to deposit glass fine particles on the starting rod in the deposition step by any one of the OVD method, the VAD method, and the MMD method.

[Details of the embodiment of the present invention]
Hereinafter, an example of an embodiment of a manufacturing method of a glass particulate deposition object and a manufacturing method of a glass base material concerning the present invention is described based on an accompanying drawing. As a manufacturing method shown below, an OVD (Outside Vapor Deposition) method will be described as an example, but the present invention is not limited to the OVD method. Similar to the OVD method, the present invention can be applied to a method of depositing glass from a glass raw material using a flame pyrolysis reaction, for example, a VAD (Vapor Phase Axial Deposition) method or an MMD (Multiburner Multilayer Deposition) method. It is.

  FIG. 1 is a configuration diagram of a manufacturing apparatus 1 that performs the method for manufacturing a glass fine particle deposit according to the present embodiment. The production apparatus 1 includes a reaction vessel 2, an elevating and rotating device 3, a raw material supply device 21, a glass particle producing burner 22, and a control unit 5 that controls the operation of each unit.

  The reaction container 2 is a container in which the glass particulate deposit M is formed, and includes an exhaust pipe 12 attached to a side surface of the container.

  The lifting / lowering rotation device 3 is a device that moves the glass particulate deposit M up and down and rotates via the support rod 10 and the starting rod 11. The lifting / lowering rotation device 3 controls the operation of the support bar 10 based on a control signal transmitted from the control unit 5. The elevating and rotating device 3 elevates and lowers the glass particulate deposit M while rotating it.

  The support rod 10 is disposed through a through hole formed in the upper wall of the reaction vessel 2, and a starting rod 11 is provided at one end portion (lower end portion in FIG. 1) disposed in the reaction vessel 2. Is attached. The other end (upper end in FIG. 1) of the support bar 10 is held by the elevating and rotating device 3.

  The starting rod 11 is a rod on which glass fine particles are deposited, and is attached to the support rod 10.

  The exhaust pipe 12 is a pipe for discharging the glass fine particles not attached to the starting rod 11 and the glass fine particle deposit M to the outside of the reaction vessel 2.

A liquid source 23 is supplied to the burner 22 by a source supply device 21. In FIG. 1, the gas supply device that supplies the flame forming gas is omitted.
The raw material supply device 21 includes a raw material container 24 that stores the liquid raw material 23, a pump 25 that supplies the liquid raw material 23, a supply pipe 26 that leads the liquid raw material 23 to the burner 22, a raw material container 24, a pump 25, and a supply pipe 26. A temperature control booth 27 for adjusting the temperature including a part of the temperature control booth 27.

  The pump 25 is a device that supplies the liquid raw material 23 emitted from the burner 22 to the burner 22 via a supply pipe 26. The pump 25 controls the supply amount of the liquid raw material 23 supplied to the burner 22 based on the control signal transmitted from the control unit 5.

  The supply pipe 26 is a pipe that guides the liquid raw material 23 to the burner 22. In order to maintain the temperature of the supply pipe 26 at a high temperature, it is preferable that a tape heater 28 as a heating element is wound around the outer periphery of the supply pipe 26 and a part of the outer periphery of the burner 22. When the tape heater 28 is energized, the supply pipe 26 and the burner 22 are heated, and the temperature of the liquid raw material 23 emitted from the burner 22 can be raised to a temperature suitable for the raw material reaction. For example, if the liquid raw material 23 is an octamethylcyclotetrasiloxane (OMCTS) liquid, the temperature may be raised to 30 to 170 ° C.

  The burner 22 vaporizes the liquid raw material 23 in a flame, and further generates a glass fine particle 30 by oxidizing the vaporized raw material.

  The control unit 5 controls each operation of the elevating and rotating device 3, the raw material supply device 21, and the like. The control unit 5 transmits a control signal for controlling the ascending / descending speed and the rotating speed of the glass particulate deposit M to the ascending / descending rotation device 3. In addition, the control unit 5 transmits a control signal for controlling the flow rate of the liquid raw material 23 emitted from the burner 22 to the pump 25 of the raw material supply device 21.

  For example, a cylindrical multi-nozzle structure or a linear multi-nozzle structure is used as the burner 22 in order to eject glass raw material or flame forming gas.

Fig.2 (a) has shown the top view of the burner surface which concerns on one form of the burner 22 which has a multi-nozzle structure.
The burner 22 shown in FIG. 2A has a raw material port 31 for ejecting the liquid raw material 23 at the center of the burner surface. In the raw material port 31, there are a liquid raw material port (an example of a glass raw material outlet) 31a through which the liquid raw material 23 is jetted, and a jet gas port (an example of a gas jet outlet) 31b around it. The ejection gas port 31b is installed so that the inner periphery thereof is disposed within 1.0 mm on the outer side from the outer periphery of the liquid source port 31a. The raw material port 31 atomizes the liquid raw material by applying the gas ejected from the ejection gas port 31b to the liquid raw material ejected from the liquid raw material port 31a. A seal gas port 32 is provided on the outer periphery of the raw material port 31. Further, around the seal gas port 32, a plurality of combustion gas ports 33 for ejecting combustion gas are concentrically arranged.
From the liquid raw material port 31 a of the central raw material port 31, for example, a siloxane liquid represented by OMCTS or the like is ejected as the liquid raw material 23. For example, gases such as nitrogen (N ₂ ), oxygen (O ₂ ), and argon (Ar) are individually or mixed and ejected from the ejection gas port 31 b of the central raw material port 31. From the seal gas port 32, for example, nitrogen (N ₂ ) or argon (Ar) gas, which is an inert gas, is supplied as a seal gas. In addition, in the combustion gas port 33, for example, hydrogen (H ₂ ) that is a combustible gas is ejected from the port 33a on the inner peripheral side, and oxygen (O ₂ ) that is the auxiliary combustion gas is ejected from the port 33b on the outer peripheral side. .

As shown in FIG. 2B, in the present embodiment, two raw material ports 31 are provided in the central portion of the burner 22. The liquid raw material port 31a of each raw material port 31 is supplied with siloxane in a liquid state, and this siloxane liquid is ejected from the liquid raw material port 31a. By using two or more raw material ports 31, the amount of the raw material ejected from one liquid raw material port 31a can be lowered, and the efficiency of chemically changing the raw material to SiO ₂ can be increased. In particular, when the raw material liquid is sprayed and emitted to the burner flame, the spray liquid diameter can be reduced, and the vaporization efficiency of the raw material liquid can be increased. The effect becomes higher as the number of glass material outlets (liquid material port 31a) increases, and if the number is 5 or more, the vaporization efficiency can be further increased. However, if too much, the price of the burner becomes expensive.

A broken line portion in FIG. 2A indicates the flame forming portion 35 in the burner 22. The flame forming part 35 has an area up to the outer side of the outermost peripheral port 33b arranged concentrically. In the present embodiment, the area of any one of the liquid source ports 31a (at least one, all in the present embodiment) is 31. It is set to be 25 × 10 ⁻⁴ or less. If the area of one liquid source port 31a is larger than 2.25 × 10 ^{−4 with} respect to the area of the flame forming portion 35, the improvement of the glass source yield when the glass particulate deposit M is produced cannot be expected.
More preferably, the area of each liquid source port 31a is set to 1.00 × 10 ⁻⁴ or less with respect to the area of the flame forming portion 35. More preferably, the area of each liquid source port 31a is 2.50 × 10 ⁻⁵ or less, more preferably 4.00 × 10 ⁻⁶ or less with respect to the area of the flame forming portion 35.
The lower limit value of the area of one liquid source port 31a is determined by the limit value of processing accuracy.

  As shown in FIG. 3, the raw material port 31 includes a liquid raw material port 31a and an ejection gas port 31b, and the ejection gas port 31b is inclined toward the liquid raw material port 31a on the inner periphery. It has a shape. Thereby, the gas injection direction is inclined toward the central axis of the liquid source port 31a, and the gas collides with the siloxane liquid ejected from the liquid source port 31a. The siloxane liquid ejected from the liquid raw material port 31a is atomized by gas collision, and spreads substantially uniformly in the radial direction of the burner 22 in the flame.

  In the present embodiment, siloxane jetted from each liquid feed port 31a, with a gas containing oxygen gas jetted at a flow rate of 855 m / s or more from a jet gas port 31b provided on the outer peripheral side in the feed port 31. By colliding with the liquid, the diameter of the siloxane spray liquid can be reduced. More preferably, the gas is ejected from the ejection gas port 31b so as to have a flow velocity of 1283 m / s or more.

Furthermore, in the present embodiment, the number of O ₂ molecules contained in the gas ejected from the ejection gas port 31b provided on the outer peripheral side in the material port 31 is included in the liquid material 23 ejected from each liquid material port 31a. It is set to be equal to or more than the number of Si atoms. By making the number of O ₂ molecules contained in the gas equal to or greater than the number of Si atoms contained in the liquid raw material 23, the efficiency of oxidizing the liquid raw material 23 to SiO ₂ can be increased. More preferably, the number of O ₂ molecules of the gas ejected from the ejection gas port 31b is 1.5 times or more the number of Si atoms of the liquid source 23 ejected from each liquid source port 31a.

Thereby, in the burner 22, the siloxane liquid is jetted into the oxyhydrogen flame generated by the flame forming gas, atomized by the collision of the gas, vaporized by the heat of the oxyhydrogen flame, and the vaporized raw material is oxygen in the flame. And silicon oxide (SiO ₂ ) particles are generated as glass fine particles 30 by a pyrolytic oxidation reaction. The generated glass particles 30 are deposited on the starting rod 11 to produce a glass particle deposit M having a predetermined outer diameter.

Next, the procedure of the method for producing the glass fine particle deposit and the glass base material will be described.
[Deposition process]
Glass fine particles are deposited by the OVD method (external method) to produce a glass fine particle deposit M. First, as shown in FIG. 1, with the support rod 10 attached to the elevating and rotating device 3, and with the start rod 11 attached to the lower end of the support rod 10, a part of the start rod 11 and the support rod 10 are placed in the reaction vessel. Put it in 2.

  Subsequently, the pump 25 supplies the liquid raw material 23 to the burner 22 while controlling the supply amount based on the control signal transmitted from the control unit 5.

  The liquid raw material 23, gas, and oxyhydrogen gas (flame forming gas) are supplied to the burner 22, the liquid raw material 23 in a sprayed state is vaporized in an oxyhydrogen flame, and then oxidized to generate glass fine particles 30. To do.

  The burner 22 continuously deposits the glass particles 30 generated in the flame on the starting rod 11 that rotates and moves up and down.

  The elevating and rotating device 3 moves up and down and rotates the starting rod 11 and the glass particulate deposit M deposited on the starting rod 11 based on a control signal from the control unit 5.

[Transparency process]
Next, the obtained glass fine particle deposit M is heated to 1100 ° C. in a mixed atmosphere of an inert gas and a chlorine gas, and then heated to 1550 ° C. in a He atmosphere to obtain a transparent glass base material. Such a glass base material is repeatedly manufactured.

As described above, in the present embodiment, in the deposition step, two liquid source ports 31a that are outlets for the glass raw material (liquid raw material 23) are provided per burner 22, and two liquids are provided. The area of the liquid material port 31a per one of the material ports 31a is 2.25 × 10 ⁻⁴ or less with respect to the area of the flame forming portion. Further, the glass raw material is supplied in a liquid state to the liquid raw material port 31a, and the inner periphery of the ejection gas port 31b is disposed at a position within 1.0 mm outside from the outer periphery of each liquid raw material port 31a, from the ejection gas port 31b. Gas is ejected. By using two or more liquid raw material ports 31a, the amount of liquid raw material 23 ejected from each liquid raw material port 31a can be reduced, and the amount of glass raw material collected when the liquid raw material 23 is chemically reacted with SiO ₂ is reduced. The rate can be improved. In particular, when the liquid raw material 23 is sprayed and emitted into the flame formed by the burner 22, the spray liquid diameter of the liquid raw material 23 can be reduced, so that the sprayed liquid raw material 23 is heated by the heat of the burner flame. The efficiency of vaporization can be increased.

Further, in the present embodiment, the area of one liquid source port 31a is 1.00 × 10 ⁻⁴ or less, more preferably 2.50 × 10 ⁻⁵ or less, more preferably with respect to the area of the flame forming portion 35. Is 4.00 × 10 ⁻⁶ or less. By doing in this way, since the liquid raw material 23 becomes easy to spread from the flame center to the outer peripheral direction of the flame by the free jet, the stirring of the raw material and oxygen is promoted, and the oxidation reaction of the raw material can be further advanced. Further, when the liquid raw material 23 is sprayed and emitted into the flame formed by the burner 22, the effect of reducing the spray liquid diameter of the liquid raw material 23 is exhibited by the above-described configuration, and the vaporization efficiency of the liquid raw material 23 is exhibited. The raw material reaction efficiency can be increased.

  Further, since the standard boiling point of OMCTS is as high as 175 ° C., it is necessary to provide a separate expensive processing device in order to vaporize the OMCTS and supply it to the burner 22 in a gas state. Therefore, in the present embodiment, OMCTS is supplied to the burner 22 in a liquid state, and gas is blown from around the OMCTS liquid ejected from the burner 22 (within 1.0 mm outside the outer periphery of the liquid raw material port 31a). As a result, the OMCTS liquid is atomized. According to this configuration, it is not necessary to provide an expensive processing device for vaporizing OMCTS, which is a glass material having a high boiling point, and the manufacturing cost of the glass particulate deposit M can be suppressed.

Further, in the present embodiment, a liquid material 23 ejected from each liquid material port 31a by ejecting a gas having a flow velocity of 855 m / s or more from an ejection gas port 31b in the vicinity of the outer periphery of each liquid material port 31a. Is atomized. Thereby, the spray liquid diameter of the liquid raw material 23 can be made small, and the vaporization efficiency of the mist-like liquid raw material 23 can be raised.
Moreover, the above-mentioned effect can be further enhanced by ejecting a gas having a flow velocity of 1283 m / s or more from the ejection gas port 31b in the vicinity of the outer periphery of each liquid source port 31a.

Further, according to the present embodiment, the number of oxygen molecules contained in the gas ejected from the ejection gas port 31b near the outer periphery of each liquid source port 31a is included in the liquid source 23 ejected from each liquid source port 31a. Or more than the number of Si atoms. Thereby, the efficiency of oxidizing the liquid raw material 23 to SiO ₂ can be increased. In addition, the number of oxygen molecules contained in the gas ejected from the ejection gas port 31b in the vicinity of the outer periphery of each liquid source port 31a is set to 1 of the number of Si atoms contained in the liquid source 23 ejected from each liquid source port 31a. By making it 5 times or more, the above-mentioned effect can be further enhanced.

In the present embodiment, siloxane which is a halogen-free raw material, preferably OMCTS liquid is used as the liquid raw material 23. Conventionally, SiCl ₄ used as a glass raw material generates SiO ₂ glass fine particles based on the following formula (1).
SiCl ₄ + 2H ₂ 0 → SiO ₂ + 4HCl Formula (1)
In this case, HCl (hydrochloric acid) that adversely affects the environment is generated as a by-product, so that a treatment apparatus that renders hydrochloric acid harmless is required, and the running cost for manufacturing the glass base material becomes very high.
On the other hand, when a siloxane liquid represented by, for example, OMCTS is used as in this embodiment, SiO ₂ glass fine particles are generated based on the following formula (2).
_{[SiO (CH 3) 2]} 4 + 16O 2 → 4SiO 2 + 8CO 2 + 12H 2 0 ... formula (2)
Thus, when siloxane, more preferably OMCTS, is used as the glass raw material supplied to the burner, harmful substances such as hydrochloric acid are not discharged. Therefore, it is not necessary to provide a processing device for removing or detoxifying harmful substances, and the manufacturing cost of the glass base material can be suppressed.

In the above embodiment, the two raw material ports 31 having the liquid raw material port 31a and the ejection gas port 31b are provided in the central portion of the burner 22, but the present invention is not limited to this example. For example, as shown to Fig.4 (a), it is good also as a structure by which the five raw material ports 31A are provided concentrically in the burner center part. Moreover, as shown in FIG.4 (b), it is good also as a structure by which the five raw material ports 31B are arrange | positioned in a row in the burner center part. Furthermore, as shown in FIG.4 (c), it is good also as a structure by which the 10 raw material ports 31C are provided concentrically in the burner center part.
Thus, by providing five or more raw material ports 31A, 31B, 31C per one burner 22, the glass raw material yield of the produced glass fine particle deposit M can be further increased.

Moreover, in the said embodiment, although the columnar burner 22 is used, it is not restricted to this example. For example, a linear burner 122 can be used as shown in FIG.
In the linear burner 122, a plurality of raw material ports 131 are arranged in a line along the longitudinal direction of the burner 122 at the center in the short direction of the burner 122. The structure of the raw material port 131 is the same as that of the raw material port 31 described above. A plurality of seal gas ports 132 are arranged on both sides of the raw material ports 131 arranged in a line. Further, a plurality of combustion gas ports 133 are arranged in two rows outside the seal gas port 132. Similar to the above-described embodiment, for example, a siloxane liquid typified by OMCTS or the like is ejected from the liquid material port (an example of the glass material outlet) of the central material port 131 as the liquid material 23. An ejection gas port exists around the liquid source port. For example, gases such as nitrogen (N ₂ ), oxygen (O ₂ ), and argon (Ar) are individually or mixed and ejected. From the seal gas port 132, for example, nitrogen (N ₂ ) or argon (Ar) gas is supplied as a seal gas. Of the combustion gas ports 133 arranged in two rows, hydrogen (H ₂ ), which is a combustible gas, is ejected from the inner port 133a, and oxygen (O ₂ ), which is a combustible gas, is ejected from the outer port 133b. Is done.

The broken line portion in FIG. 5 shows the flame forming portion 135 in the burner 122. The flame forming part 135 has an area up to the outside of the port 133b arranged at both ends. Similar to the above embodiments, linear even in the burner 122, 2.25 × the area of the liquid material port of any one of the raw material port 131 to the area of the flame formation portion 135 of the feed ports 131 10 ^- It is set to be ⁴ or less.
More preferably, the area of the liquid source port of each source port 131 is set to 1.00 × 10 ⁻⁴ or less with respect to the area of the flame forming portion 135. More preferably, the area of the liquid source port of each source port 131 is 2.50 × 10 ⁻⁵ or less, more preferably 4.00 × 10 ⁻⁶ or less with respect to the area of the flame forming portion 35.

According to the linear burner 122 as shown in FIG. 5, the input amount of the liquid raw material 23 ejected from each raw material port 131 can be reduced similarly to the above embodiment, and the liquid raw material 23 is chemically reacted with SiO ₂ . The glass raw material yield at the time of making it can be improved. In particular, when the liquid raw material 23 is sprayed and emitted into the flame formed by the linear burner 122, the spray liquid diameter of the liquid raw material 23 can be reduced. The efficiency of vaporization by the heat of can be increased.

In the above embodiment, OMCTS is described as an example of the siloxane liquid. However, other siloxanes such as DMCPS have the same effect as the above embodiment.
Moreover, even if it is raw materials other than siloxane such as SiCl _4, the effect of increasing the glass raw material yield is also the same.

  1 is deposited by the OVD method, that is, the glass particulate deposit M is produced [deposition step]. Further, the obtained glass fine particle deposit M is heated to 1100 ° C. in a mixed atmosphere of an inert gas and a chlorine gas, and then heated to 1550 ° C. in a He atmosphere to perform transparent vitrification [translucent step].

Pure quartz glass having a diameter of 36 mm and a length of 400 mm is used as the starting rod. The OMCTS liquid which is 16.5 g / min in total is supplied to all liquid raw material ports of the burner. When there are five liquid source ports in one burner, the Si atom flow rate per port is 0.044 mol / min. H ₂ (flow rate: 20 to 70 SLM) and O ₂ (flow rate: 30 to 70 SLM) are supplied as the flame forming gas, and Ar (flow rate of 1 to 8 SLM) is supplied as the burner seal gas.

In the above deposition step, the number of raw material ports per burner X, the ratio Y of the area of one liquid raw material port to the area of the flame forming portion, and the vicinity of the outer periphery of each liquid raw material port (spouting gas port) It is produced by appropriately changing the O ₂ molecular flow rate Z (mol / min) in the gas and the flow velocity W (m / s) of the gas ejected from each ejection gas port, and depositing glass particles on the starting rod. The raw material yield A (%) of the glass fine particle deposit and the equipment cost of each example are relatively evaluated. In addition, the area of a flame formation part is defined by the area of the broken line part of the burner shown to Fig.2 (a) and FIG. Moreover, in each Example, the exit area of the liquid material port and the ejection gas port installed in the burner is the same for the liquid material ports in the burner of the example, and the ejection gas ports are the same. In each embodiment, the inner periphery of the ejection gas port is located 0.9 mm away from the outer periphery of the liquid source port. On the other hand, in the comparative example, the inner periphery of the ejection gas port is located 1.1 mm away from the outer periphery of the liquid source port. The raw material yield A is the mass ratio of the glass particles actually deposited on the starting rod and the glass particle deposit to the SiO ₂ mass when the OMCTS liquid charged into the burner chemically reacts with 100% quartz glass particles. It is. In addition, a multi-nozzle type burner shown in FIG. 2A is used as the burner A, and a linear burner shown in FIG.
The results are shown in Table 1.

[Example 1]
From Example 1, the number of raw material ports per burner is two, the ratio of the area of one liquid raw material port to the area of the flame forming portion is 2.50 × 10 ⁻⁵ , and the gas jetted from each jet gas port Assuming that the O ₂ molecular flow rate is 0.027 mol / min and the flow rate of the gas ejected from each ejection gas port is 513 m / s, the raw material yield is 50%.

[Comparative Example 1]
On the other hand, as in Comparative Example 1, the number of raw material ports per burner is one, and the ratio of the area of the liquid raw material port to the area of the flame forming portion is larger than 2.50 × 10 ⁻⁵ , for example 4 .00 × 10 ⁻⁴ , and when the inner periphery of the ejection gas port is 1.1 mm away from the outer periphery of the liquid source port, the O ₂ molecular flow rate Z of the gas ejected from each ejection gas port and each ejection gas port Even if the flow velocity W of the gas ejected from the same value as in Example 1, the raw material yield remains 20%.

From this result, the number of the raw material ports per burner is set to two or more, the ratio of the area of the liquid raw material port to the area of the flame forming portion is smaller than 2.25 × 10 ⁻⁴ , and at least the ejection gas port It can be confirmed that the raw material yield is greatly improved by installing a part within 1.0 mm from the outer periphery of the liquid raw material port.

[Examples 2 to 5]
In Examples 2 to 5, the number X of raw material ports per burner unit is increased from that in Example 1, Example 2 has 5 raw material ports, Example 3 has 10 raw material ports, and Example 4 has raw material ports. Burners with 50 ports and Example 5 with 100 raw material ports are used. In Examples 2 to 5, the ratio Y of the area of one liquid source port to the area of the flame forming portion, the O ₂ molecular flow rate Z of the gas ejected from each ejection gas port, and the gas ejected from each ejection gas port The same value as in Example 1 is used for the flow velocity W of.
As a result, as shown in Table 1, it can be confirmed that the raw material yield improves as the number of raw material ports per burner increases. In Examples 4 and 5, the linear burner of FIG. 5 is used as the burner.

[Examples 6 to 8]
In Examples 6 to 8, the ratio Y of the area of one liquid source port to the area of the flame forming portion was changed, and Example 6 was 2.25 × 10 ⁻⁴ , and Example 7 was 1.00 ×. 10 ⁻⁴ , Example 8 uses a burner that is 4.00 × 10 ⁻⁶ . In Examples 6 to 8, the number X of raw material ports per burner unit, the O ₂ molecular flow rate Z of the gas ejected from each ejection gas port, and the flow velocity W of the gas ejected from each ejection gas port The same value as 2 is used.
As a result, as shown in Example 6 of Table 1, the ratio of the area of one liquid source port to the area of the flame forming portion is 2.25 × 10 ⁻⁴ or less, compared with Comparative Example 1. It can be confirmed that the raw material yield is sufficiently improved. Further, from the results of Examples 2 and 6 to 8, it can be confirmed that the raw material yield is improved as the ratio Y of the area of one liquid raw material port to the area of the flame forming portion is decreased.

[Examples 9 to 12]
In Examples 9 to 12, the O ₂ molecular flow rate Z of the gas ejected from each ejection gas port and the value of the flow velocity W of the gas ejected from each ejection gas port were changed. In Example 9, 0 mol / min and 513 m / s, Example 10 is 0.045 mol / min and 856 m / s, Example 11 is 0.067 mol / min and 1284 m / s, and Example 12 is 0.089 mol / min and 1711 m / s. In Examples 9 to 12, the same value as in Example 2 is used for the number X of raw material ports per burner and the ratio Y of the area of one liquid raw material port to the area of the flame forming portion.
As a result, as shown in Table 1, it can be confirmed that the raw material yield is sufficiently improved as compared with Comparative Example 1 by increasing the O ₂ molecular flow rate Z of the gas ejected from each ejection gas port. Specifically, as in Example 10, the O ₂ molecular flow rate (0.045 mol / min) in the gas is set to be equal to or higher than the Si atom flow rate (0.044 mol / min) in the OMCTS ejected as the liquid raw material. Thus, the raw material yield is greatly improved. Moreover, since the raw material yield is further improved when the number of O ₂ molecules in the gas is 1.5 times the number of Si atoms in the OMCTS as in Examples 11 and 12, the raw material yield increases as the molecular flow rate Z increases. It can be confirmed that the rate is improved. Further, Example 9 is an example in which the O ₂ molecular flow rate is 0 mol / min. However, even if the flow velocity W of the gas ejected from each ejection gas port is the same value as in Comparative Example 1, the raw material yield is in Example 9. It can be seen that is overwhelmingly higher. Therefore, the number of raw material ports per burner is two or more, the ratio of the area of the liquid raw material port to the area of the flame forming portion is 2.25 × 10 ⁻⁴ or less, and the jet gas port is used as the liquid raw material. It can be seen that it is important to improve the raw material yield to be installed within the range of 1.0 mm from the outer periphery of the service port.

[Examples 13 to 15]
In Examples 13 to 15, the flow velocity W of the gas ejected from the ejection gas port is 152 m / s in Example 13, 856 m / s in Example 14, and 2158 m / s in Example 15. In Examples 13 to 15, the number X of raw material ports per burner, the ratio Y of the area of one liquid raw material port to the area of the flame forming portion, and O _{2 of} the gas ejected from each ejection gas port The molecular flow rate Z uses the same value as in Example 2.
As a result, as shown in Table 1, it can be confirmed that the raw material yield is sufficiently improved as compared with Comparative Example 1 by setting the flow velocity W of the gas ejected from each ejection gas port to 152 m / s or more. Moreover, from the results of Examples 2 and 13 to 15, it can be confirmed that the raw material yield is improved as the flow velocity W is increased.

[Comparative Examples 2 and 3]
Comparative examples 2 and 3 are examples in which the number of raw material ports is one and the respective parameters are changed as in comparative example 1. From the above-mentioned Examples 9 to 15, when the O ₂ molecular flow rate Z of the gas ejected from each ejection gas port is increased or the flow velocity W of the gas ejected from each ejection gas port is increased, the result that the raw material yield is improved. Has been obtained. However, as shown in Comparative Examples 2 and 3 in Table 1, the number of raw material ports per burner is one, and the ratio Y of the area of one liquid raw material port to the area of the flame forming portion is large, When the inner periphery of the ejection gas port is more than 1.0 mm away from the outer periphery of the liquid raw material port, there is a slight effect of changing each parameter, but the raw material yield cannot be improved to the value of the example. .
[Comparative Example 4]
Although the comparative example 4 is an example which supplies a raw material to a burner in the state which vaporized, since an expensive vaporizer (illustration omitted) is required, when supplying a raw material with a liquid (Examples 1-15, comparative example) It can be seen that the equipment cost is 1.3 times that of 1 to 3). Further, when the vaporized raw material is emitted from the liquid raw material port and a gas containing an O ₂ molecular flow rate of 0.027 mol / min is introduced from the outer periphery, glass particles are generated in the vicinity of the burner, and the glass particles are deposited on the burner. As a result, there is a problem that the burner is clogged. For this reason, the raw material yield cannot be measured.

  While the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. In addition, the number, position, shape, and the like of the constituent members described above are not limited to the above-described embodiments, and can be changed to a number, position, shape, and the like that are suitable for carrying out the present invention.

1: Manufacturing device 2: Reaction vessel 3: Elevating and rotating device 5: Control unit 10: Support rod 11: Starting rod 21: Raw material supply device 22: Burner 23: Liquid raw material 24: Raw material container 25: Pump 26: Supply piping 27: Temperature control booth 28: Tape heater 30: Glass fine particles 31: Raw material port 31a: Port for liquid raw material (an example of a glass raw material outlet)
31b: ejection gas port (an example of a gas ejection port)
32: Seal gas port 33: Combustion gas port 35: Flame formation part 122: Linear burner 131: Raw material port 132: Seal gas port 133: Combustion gas port 135: Flame formation part M: Glass particulate deposit

Claims (15)

A starting rod and a glass fine particle production burner are installed in the reaction vessel, glass raw material is introduced into the burner, and glass fine particles are generated by flame pyrolysis reaction in the flame formed by the burner. A method for producing a glass particulate deposit having a deposition step of depositing the glass particulate on the starting rod to produce a glass particulate deposit,
In the deposition step, at least two glass material outlets ejected from the burner are provided per burner, and the area of at least one of the outlets is 2.25 of the area of the flame forming portion of the burner. × 10 ^-4 or less, and the glass raw material is supplied to each of the outlets in a liquid state, and the gas outlets arranged in concentric relation with the glass raw material outlets in contact with the outside of the glass raw material outlets Provided, the gas outlet is disposed within 1.0 mm from the outer periphery of each glass raw material outlet around the entire circumference of each glass raw material outlet, gas is jetted from the gas outlet, and the glass raw material is fogged A method for producing a glass fine particle deposit.   2. The method for producing a glass particulate deposit according to claim 1, wherein, in the deposition step, the ejection gas port has a shape in which a tip end portion is inclined toward an inner liquid source port.   3. The method for producing a glass particulate deposit according to claim 1, wherein, in the deposition step, five or more outlets are provided per one burner. 4. The glass particulate deposit according to claim 1, wherein in the deposition step, an area of the one emission port is set to 1.00 × 10 ⁻⁴ or less of an area of the flame forming portion. 5. Manufacturing method. 4. The glass fine particle deposit according to claim 1, wherein, in the deposition step, an area of the one emission port is set to 2.50 × 10 ⁻⁵ or less of an area of the flame forming portion. ^5. Manufacturing method. 4. The glass particulate deposit according to claim 1, wherein, in the deposition step, an area of the one emission port is 4.00 × 10 ⁻⁶ or less of an area of the flame forming portion. 5. Manufacturing method.   The said deposition process WHEREIN: The gas containing oxygen gas is ejected from the said gas ejection port, The said glass raw material ejected from each said ejection port is atomized, It is any one of Claims 1-6. A method for producing a glass particulate deposit.   The glass particle deposition according to claim 7, wherein, in the deposition step, a gas having a flow velocity of 856 m / s or more is ejected from each gas ejection port to atomize the glass raw material ejected from each ejection port. Body manufacturing method.   The glass particle deposition according to claim 7, wherein in the deposition step, a gas having a flow velocity of 1283 m / s or more is ejected from each gas ejection port to atomize the glass raw material ejected from each ejection port. Body manufacturing method.   The said deposition process WHEREIN: The oxygen molecule number contained in the said gas ejected from each said gas ejection port shall be more than the number of Si atoms contained in the said glass raw material ejected from each said ejection port. 9. A method for producing a glass fine particle deposit according to 9.   In the deposition step, the number of oxygen molecules contained in the gas ejected from each gas ejection port is 1.5 times or more the number of Si atoms contained in the glass raw material ejected from each emission port. Item 10. A method for producing a glass particulate deposit according to Item 8 or Item 9.   The method for producing a glass particulate deposit according to any one of claims 1 to 11, wherein in the deposition step, the glass raw material supplied to the burner is siloxane.   The method for producing a glass particulate deposit according to any one of claims 1 to 11, wherein in the deposition step, the glass raw material supplied to the burner is octamethylcyclotetrasiloxane (OMCTS).   A glass particulate deposit is produced by the method for producing a glass particulate deposit according to any one of claims 1 to 13, and the produced glass particulate deposit is heated to produce a transparent glass base material. A method for producing a glass base material, comprising a transparentization step. Glass particles are deposited on the starting rod in the deposition step by OVD method, VAD method,
The manufacturing method of the glass base material of Claim 14 performed by either of MMD methods.

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