WO2023038124A1 - Device and method for manufacturing glass preform for optical fiber - Google Patents

Device and method for manufacturing glass preform for optical fiber Download PDF

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Publication number
WO2023038124A1
WO2023038124A1 PCT/JP2022/033929 JP2022033929W WO2023038124A1 WO 2023038124 A1 WO2023038124 A1 WO 2023038124A1 JP 2022033929 W JP2022033929 W JP 2022033929W WO 2023038124 A1 WO2023038124 A1 WO 2023038124A1
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Prior art keywords
supply pipe
raw material
optical fiber
vaporizer
degasser
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PCT/JP2022/033929
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French (fr)
Japanese (ja)
Inventor
盛司 荒川
正敏 早川
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住友電気工業株式会社
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Publication of WO2023038124A1 publication Critical patent/WO2023038124A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/018—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Definitions

  • the present disclosure relates to an optical fiber glass preform manufacturing apparatus and an optical fiber glass preform manufacturing method.
  • This application claims priority based on Japanese Patent Application No. 2021-147769 filed on September 10, 2021, and incorporates all the descriptions described in the Japanese Patent Application.
  • Patent Document 1 discloses a manufacturing apparatus that implements a method for manufacturing a glass particulate deposit.
  • the manufacturing apparatus includes a reaction vessel, a gas supply device, and a burner for producing glass microparticles.
  • the apparatus for manufacturing an optical fiber glass preform includes: A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. and a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe.
  • the manufacturing method of the glass preform for optical fiber of the present disclosure includes: A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. It is a manufacturing method of the glass base material for optical fibers to be used.
  • FIG. 1 is a diagram showing an apparatus for manufacturing an optical fiber glass preform according to an embodiment.
  • An apparatus for manufacturing an optical fiber glass preform ejects a raw material from a burner, oxidizes it in a flame to form glass particles, and deposits the glass particles to produce an optical fiber glass preform. If the raw material is liquid, the raw material is pressurized by gas in the tank and supplied to the vaporizer. However, if the supply amount of the raw material fluctuates, the amount of the formed glass particles also fluctuates, which may cause molding defects in the optical fiber glass preform.
  • An object of the present disclosure is to provide an apparatus for manufacturing an optical fiber glass preform and a method for manufacturing an optical fiber glass preform that can suppress the occurrence of molding defects in the optical fiber glass preform.
  • An apparatus for manufacturing an optical fiber glass preform includes: A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. and a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe.
  • the gas dissolved in the liquid raw material sometimes spouts out as bubbles and stays in the supply pipe.
  • the degasser is provided in the supply pipe, it is possible to remove the gas inside the supply pipe, and it is possible to suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of molding defects in the optical fiber glass preform can be suppressed.
  • the supply pipe may extend vertically upward and then vertically downward from upstream to downstream.
  • gas tends to stay at the top in the vertical direction of the supply pipe.
  • At least one degasser may be provided at the top in the vertical direction of the supply pipe or at a portion downstream of the top in the raw material supply channel.
  • the gas inside the supply pipe can be preferably removed.
  • a method for manufacturing an optical fiber glass preform includes: A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. It is a manufacturing method of the glass base material for optical fibers to be used. The gas dissolved in the liquid raw material sometimes spouts out as bubbles and stays in the supply pipe.
  • the degasser is provided in the supply pipe, it is possible to remove the gas inside the supply pipe, and it is possible to suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of molding defects in the optical fiber glass preform can be suppressed.
  • the supply pipe may extend vertically upward and then vertically downward from upstream to downstream.
  • gas tends to stay at the top in the vertical direction of the supply pipe.
  • At least one degasser may be provided at the top in the vertical direction of the supply pipe or at a portion downstream of the top in the raw material supply channel.
  • the gas inside the supply pipe can be preferably removed.
  • FIG. 1 is a configuration diagram of an apparatus 100 for manufacturing an optical fiber glass preform 8 according to an embodiment.
  • the manufacturing apparatus 100 includes a tank 10 , a supply pipe 40 , a supply device 20 , a burner 30 and a reaction vessel 130 .
  • the arrow labeled A in FIG. 1 indicates the vertical direction.
  • the tank 10 is installed on the vertically lower floor 110
  • the feeder 20 , the burner 30 and the reaction vessel 130 are installed on the vertically upper floor 120 .
  • the supply pipe 40 is laid across the lower floor 110 and the upper floor 120 .
  • the tank 10 is a container that stores the liquid raw material 2 that forms the basis of the glass fine particles 6 .
  • the liquid raw material 2 include silicon tetrachloride and siloxane (eg, octamethylcyclotetrasiloxane).
  • liquid source 2 is pressurized with gas 4 and introduced into supply pipe 40 .
  • gas for pressurizing the liquid raw material 2 an inert gas such as He that is sparingly soluble in liquid at room temperature (20° C.) is used.
  • the supply pipe 40 is a pipe that guides the liquid raw material 2 to the burner 30 .
  • the supply pipe 40 is connected with the burner 30 .
  • the supply device 20 is provided on the supply pipe 40 at a position immediately before the portion connected to the burner 30 . In FIG. 1, five burners 30 and five feeders 20 are shown by way of example.
  • the supply pipe 40 branches into five between the tank 10 and the supply device 20 .
  • a supply device 20 is provided in each of the branched supply pipes 40 .
  • the supply pipe 40 extends vertically upward and then vertically downward from upstream to downstream. Specifically, the supply pipe 40 extends to the top of the upper floor 120 and then extends vertically downward in steps to the position of the supply device 20 .
  • a degasser 42 is provided at a vertical uppermost portion 44 of the supply pipe 40 .
  • a degasser 42 is a device that removes gas from a liquid using a degassing membrane. Specifically, the degasser 42 is connected between the supply pipes 40 to remove gas in the liquid source 2 on-line.
  • the aspect of the convex pipe in the present disclosure does not refer only to the aspect of the pipe that bends at a strictly right angle, but the aspect of the pipe that bends at an obtuse angle or an acute angle, or the aspect of the curved pipe that vertically extends the supply pipe 40 upward. Including those that protrude.
  • the aspect of convex piping in the present disclosure also includes the aspect of piping including a portion in which the supply pipe extends obliquely with respect to the vertical direction.
  • the degasser 42 may be provided at a portion 46 downstream of the uppermost portion 44 of the supply pipe 40 in the supply channel of the liquid raw material 2 , instead of the uppermost portion 44 .
  • the supply device 20 includes, for example, a supply section 22, a vaporization device 24, a control valve 26, and a mass flow meter (MFM) 28. These are arranged in the order of the MFM 28 , the control valve 26 , the vaporizer 24 and the supply section 22 from the upstream in the supply flow path of the liquid raw material 2 .
  • the MFM 28 is a device that measures the supply flow rate of the liquid raw material 2 .
  • the control valve 26 is a valve that controls the supply flow rate of the liquid raw material 2 to the vaporizer 24 .
  • the control valve 26 is configured to control the degree of opening of the valve based on the supply flow rate of the liquid raw material 2 detected by the MFM 28 .
  • the vaporizer 24 is a device that introduces a carrier gas such as nitrogen into the liquid raw material 2 to vaporize the liquid raw material 2 (into a mist state).
  • the supply part 22 is a part that supplies the liquid raw material 2 in a mist state to the burner 30 .
  • the burner 30 is a member that generates the glass microparticles 6 by thermally decomposing and oxidizing the vaporized raw material in a flame inside the reaction vessel 130 .
  • the burner 30 sprays and deposits the generated glass fine particles 6 on the starting rod 132 rotating about the axis, thereby manufacturing the optical fiber glass preform 8 .
  • the burner 30 is supplied with a flame forming gas such as H 2 and O 2 and an inert gas such as N 2 and Ar as a burner sealing gas.
  • the reaction vessel 130 includes, for example, a burner 30, an end heating burner 32, and an exhaust section 134.
  • a starting rod 132 is arranged at a predetermined position when manufacturing the optical fiber glass preform 8.
  • the exhaust part 134 is a part for discharging the glass particles 6 that have not adhered to the starting rod 132 and the optical fiber glass base material 8 to the outside of the reaction vessel 130 together with the gas inside the reaction vessel 130 .
  • the end heating burners 32 are burners for heating the upper and lower ends of the optical fiber glass preform 8 . In FIG. 1, two end heating burners 32 are shown by way of example. The two end heating burners 32 are arranged so as to sandwich the five burners 30 from above and below.
  • a method for manufacturing an optical fiber glass preform according to the present embodiment using the manufacturing apparatus 100 described above will be described.
  • a manufacturing apparatus 100 in which a degasser 42 is provided in a supply pipe 40 is used. Then, the vaporized raw material is supplied to the burner 30 via the supply device 20, and the glass microparticles 6 are generated by thermally decomposing and oxidizing the raw material in the flame. Then, the generated glass particles 6 are sprayed and deposited on the starting rod 132 rotating about the axis to manufacture the optical fiber glass preform 8 .
  • Gases such as He are generally poorly soluble in liquids. Melt into raw materials. When the pressure applied to the liquid raw material drops due to pressure loss in the supply pipe or the like, the dissolved gas gushes out as bubbles. If this bubbling gas stays in the supply pipe and the staying gas flows into the supply device at once in a short period of time, a hunting phenomenon may occur. For example, when an MFM is employed, if stagnant gas flows into the MFM at once in a short period of time, the flow rate detected by the MFM becomes 0, the opening of the control valve increases, and a hunting phenomenon occurs. As a result, the liquid raw material flows into the vaporizer at once in a short time, and a large amount of raw material gas is jetted out. If such a hunting phenomenon occurs, there is a possibility that the manufactured optical fiber glass preform may have a molding defect.
  • the degasser 42 is provided in the supply pipe 40, so that the gas inside the supply pipe 40 can be removed, and the stagnant gas is vaporized at once in a short time. It is possible to suppress the instability of the raw material supply due to the raw material flowing into 24 . As a result, the occurrence of molding defects in the optical fiber glass preform can be suppressed.
  • destabilization of raw material supply can also be suppressed by providing a degasser 42 in a supply pipe having a shape other than a convex shape.
  • the degasser 42 is provided in the supply pipe 40 to prevent the supply of the raw material from becoming unstable. can be suppressed.
  • At least the uppermost portion 44 in the vertical direction of the supply pipe 40 where gas tends to accumulate or the portion 46 downstream of the uppermost portion 44 in the supply channel of the liquid raw material 2 is at least
  • the gas inside the supply pipe 40 can be preferably removed, and the instability of the raw material supply due to the stagnant gas flowing into the vaporizer 24 in a short period of time can be suppressed. can.
  • the occurrence of poor molding of the optical fiber glass preform can be suitably suppressed.
  • siloxane has a higher boiling point than silicon tetrachloride and is difficult to vaporize, it is necessary to supply it in a liquid state for a longer period. Therefore, if the present disclosure is applied when siloxane is used as a raw material, the occurrence of the hunting phenomenon can be suppressed more appropriately.
  • a pipe having an outer diameter of 4 mm to 10 mm and an inner diameter of about 3 mm to 9 mm can be used as the pipe of the supply pipe 40.
  • the inner diameter of the pipe is smaller than 3 mm, the pressure loss increases, and when the inner diameter is larger than 9 mm, air bubbles tend to increase due to cavities in the pipe.
  • Table 1 shows the presence or absence of hunting when the supply pipe 40 having a convex shape is provided with the degasser 42 and when it is not provided.
  • the presence or absence of hunting was examined for the case where the degasser 42 was provided at the top of the supply pipe 40 and the case where the degasser 42 was provided at the inlet portion of the supply pipe 40 .
  • the supply pipe 40 was made of Teflon (registered trademark) and had an inner diameter of 4 mm and an outer diameter of 6 mm.
  • a liquid glass raw material was supplied to the supply pipe 40 at a set supply amount of 50 g/min.
  • “Top” is “the highest position in the pipe having a convex shape”
  • “introducing the degasser to the top” in Table 1 means that the degasser pipe is connected to the “top”
  • the results are shown when
  • the "inlet part” is “a position on the upstream side separated by a pipe length of 1 m or more from the uppermost position of the pipe having a convex shape”
  • "Introducing the degasser to the inlet part” in Table 1 shows the results when the degasser pipe is connected to the "inlet”.

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  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
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Abstract

The present disclosure pertains to a device for manufacturing a glass preform for an optical fiber, said device comprising: a tank for pressurizing a liquid starting material with a gas; a vaporizer for vaporizing the pressurized starting material; a burner for blowing out the starting material vaporized by the vaporizer and thus forming fine glass particles; and a supply pipe for supplying the starting material pressurized in the tank to the vaporizer, wherein the supply pipe is provided with a degasser for removing the gas accumulated in the supply pipe.

Description

光ファイバ用ガラス母材の製造装置および光ファイバ用ガラス母材の製造方法Optical fiber glass preform manufacturing apparatus and optical fiber glass preform manufacturing method
　本開示は、光ファイバ用ガラス母材の製造装置および光ファイバ用ガラス母材の製造方法に関する。本出願は、２０２１年９月１０日出願の日本国特許出願第２０２１－１４７７６９号に基づく優先権を主張し、前記日本国特許出願に記載された全ての記載内容を援用するものである。 The present disclosure relates to an optical fiber glass preform manufacturing apparatus and an optical fiber glass preform manufacturing method. This application claims priority based on Japanese Patent Application No. 2021-147769 filed on September 10, 2021, and incorporates all the descriptions described in the Japanese Patent Application.
　特許文献１は、ガラス微粒子堆積体の製造方法を実施する製造装置を開示している。当該製造装置は、反応容器と、ガス供給装置と、ガラス微粒子生成用のバーナーと、を備えている。 Patent Document 1 discloses a manufacturing apparatus that implements a method for manufacturing a glass particulate deposit. The manufacturing apparatus includes a reaction vessel, a gas supply device, and a burner for producing glass microparticles.
日本国特開２０１４－２２４００７号公報Japanese Patent Application Laid-Open No. 2014-224007
　本開示の光ファイバ用ガラス母材の製造装置は、
　液体の原料をガスで加圧するタンクと、加圧された前記原料を気化させる気化装置と、前記気化装置で気化された前記原料を噴出させてガラス微粒子を形成するバーナーと、前記タンクで加圧された前記原料を前記気化装置に供給する供給管と、を備え、前記供給管に、前記供給管内に滞留したガスを除去するデガッサーが設けられている、光ファイバ用ガラス母材の製造装置である。 The apparatus for manufacturing an optical fiber glass preform according to the present disclosure includes:
A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. and a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. be.
　本開示の光ファイバ用ガラス母材の製造方法は、
　液体の原料をガスで加圧するタンクと、加圧された前記原料を気化させる気化装置と、前記気化装置で気化された前記原料を噴出させてガラス微粒子を形成するバーナーと、前記タンクで加圧された前記原料を前記気化装置に供給する供給管と、を備え、前記供給管に、前記供給管内に滞留したガスを除去するデガッサーが設けられている、光ファイバ用ガラス母材の製造装置を用いる光ファイバ用ガラス母材の製造方法である。 The manufacturing method of the glass preform for optical fiber of the present disclosure includes:
A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. It is a manufacturing method of the glass base material for optical fibers to be used.
図１は実施形態に係る光ファイバ用ガラス母材の製造装置を示す図である。FIG. 1 is a diagram showing an apparatus for manufacturing an optical fiber glass preform according to an embodiment.
［本開示が解決しようとする課題］
　光ファイバ用ガラス母材の製造装置は、原料をバーナーから噴出し、火炎中において酸化反応させることでガラス微粒子を形成し、このガラス微粒子を堆積させることで光ファイバ用ガラス母材を製造する。原料が液体である場合には、原料をタンク内でガスによって加圧して気化装置へ供給する。しかしながら、この原料の供給量が変動すると形成されるガラス微粒子の量も変動し、光ファイバ用ガラス母材に成形不良が発生する場合がある。 [Problems to be Solved by the Present Disclosure]
An apparatus for manufacturing an optical fiber glass preform ejects a raw material from a burner, oxidizes it in a flame to form glass particles, and deposits the glass particles to produce an optical fiber glass preform. If the raw material is liquid, the raw material is pressurized by gas in the tank and supplied to the vaporizer. However, if the supply amount of the raw material fluctuates, the amount of the formed glass particles also fluctuates, which may cause molding defects in the optical fiber glass preform.
　本開示は、光ファイバ用ガラス母材の成形不良の発生を抑制できる、光ファイバ用ガラス母材の製造装置および光ファイバ用ガラス母材の製造方法を提供することを目的とする。 An object of the present disclosure is to provide an apparatus for manufacturing an optical fiber glass preform and a method for manufacturing an optical fiber glass preform that can suppress the occurrence of molding defects in the optical fiber glass preform.
［本開示の効果］
　本開示によれば、光ファイバ用ガラス母材の成形不良の発生を抑制できる、光ファイバ用ガラス母材の製造装置および光ファイバ用ガラス母材の製造方法を提供できる。 [Effect of the present disclosure]
ADVANTAGE OF THE INVENTION According to this indication, the manufacturing apparatus of the glass preform for optical fibers and the manufacturing method of the glass preform for optical fibers which can suppress generation|occurrence|production of the molding defect of the glass preform for optical fibers can be provided.
［本開示の実施形態の説明］
　最初に本開示の実施形態を列記して説明する。
（１）実施形態に係る光ファイバ用ガラス母材の製造装置は、
　液体の原料をガスで加圧するタンクと、加圧された前記原料を気化させる気化装置と、前記気化装置で気化された前記原料を噴出させてガラス微粒子を形成するバーナーと、前記タンクで加圧された前記原料を前記気化装置に供給する供給管と、を備え、前記供給管に、前記供給管内に滞留したガスを除去するデガッサーが設けられている、光ファイバ用ガラス母材の製造装置である。
　液体の原料に溶存したガスは、気泡として湧き出して供給管に滞留することがある。供給管にデガッサーが設けられていることで供給管の内部のガスを取り除くことができ、滞留したガスが短時間で一気に気化装置に流れ込むことによる原料の供給の不安定化を抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を抑制できる。 [Description of Embodiments of the Present Disclosure]
First, the embodiments of the present disclosure will be listed and described.
(1) An apparatus for manufacturing an optical fiber glass preform according to an embodiment includes:
A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. and a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. be.
The gas dissolved in the liquid raw material sometimes spouts out as bubbles and stays in the supply pipe. Since the degasser is provided in the supply pipe, it is possible to remove the gas inside the supply pipe, and it is possible to suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of molding defects in the optical fiber glass preform can be suppressed.
（２）上記（１）の光ファイバ用ガラス母材の製造装置は、
　前記供給管が、上流から下流に向かって、鉛直方向上方に延びてから鉛直方向下方に延びていてもよい。
　鉛直方向上方に延びてから鉛直方向下方に延びる凸型の形状を有する供給管では、供給管の鉛直方向の最上部にガスが滞留しやすい。凸型の形状を有する供給管にデガッサーを設けることで、滞留したガスが短時間で一気に気化装置に流れ込むことによる原料の供給の不安定化を好適に抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を好適に抑制できる。 (2) The apparatus for manufacturing an optical fiber glass preform according to (1) above,
The supply pipe may extend vertically upward and then vertically downward from upstream to downstream.
In a supply pipe having a convex shape that extends vertically upward and then vertically downward, gas tends to stay at the top in the vertical direction of the supply pipe. By providing the degasser in the convex supply pipe, it is possible to suitably suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of poor molding of the optical fiber glass preform can be suitably suppressed.
（３）上記（２）の光ファイバ用ガラス母材の製造装置は、
　前記デガッサーが、前記供給管の鉛直方向の最上部または前記最上部よりも前記原料の供給流路における下流の部分に少なくとも一つ設けられていてもよい。
　ガスの溜まりやすい供給管の鉛直方向の最上部または前記最上部よりも前記原料の供給流路における下流の部分に少なくとも一つのデガッサーを設けることで供給管の内部のガスを好適に取り除くことができる。また、滞留したガスが短時間で一気に気化装置に流れ込むことによる原料の供給の不安定化を好適に抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を好適に抑制できる。 (3) The apparatus for manufacturing the optical fiber glass base material of (2) above,
At least one degasser may be provided at the top in the vertical direction of the supply pipe or at a portion downstream of the top in the raw material supply channel.
By providing at least one degasser at the top of the supply pipe in the vertical direction where gas tends to accumulate or at a portion downstream of the top in the supply channel of the raw material, the gas inside the supply pipe can be preferably removed. . In addition, it is possible to suitably suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of molding defects in the optical fiber glass preform can be suitably suppressed.
（４）実施形態に係る光ファイバ用ガラス母材の製造方法は、
　液体の原料をガスで加圧するタンクと、加圧された前記原料を気化させる気化装置と、前記気化装置で気化された前記原料を噴出させてガラス微粒子を形成するバーナーと、前記タンクで加圧された前記原料を前記気化装置に供給する供給管と、を備え、前記供給管に、前記供給管内に滞留したガスを除去するデガッサーが設けられている、光ファイバ用ガラス母材の製造装置を用いる光ファイバ用ガラス母材の製造方法である。
　液体の原料に溶存したガスは、気泡として湧き出して供給管に滞留することがある。供給管にデガッサーが設けられていることで供給管の内部のガスを取り除くことができ、滞留したガスが短時間で一気に気化装置に流れ込むことによる原料の供給の不安定化を抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を抑制できる。 (4) A method for manufacturing an optical fiber glass preform according to an embodiment includes:
A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. It is a manufacturing method of the glass base material for optical fibers to be used.
The gas dissolved in the liquid raw material sometimes spouts out as bubbles and stays in the supply pipe. Since the degasser is provided in the supply pipe, it is possible to remove the gas inside the supply pipe, and it is possible to suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of molding defects in the optical fiber glass preform can be suppressed.
（５）上記（４）の光ファイバ用ガラス母材の製造方法は、
　前記供給管が、上流から下流に向かって、鉛直方向上方に延びてから鉛直方向下方に延びていてもよい。
　鉛直方向上方に延びてから鉛直方向下方に延びる凸型の形状を有する供給管では、供給管の鉛直方向の最上部にガスが滞留しやすい。凸型の形状を有している供給管にデガッサーを設けることで、滞留したガスが短時間で一気に気化装置に流れ込むことによる原料の供給の不安定化を好適に抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を好適に抑制できる。 (5) The method for producing the optical fiber glass base material of (4) above,
The supply pipe may extend vertically upward and then vertically downward from upstream to downstream.
In a supply pipe having a convex shape that extends vertically upward and then vertically downward, gas tends to stay at the top in the vertical direction of the supply pipe. By providing the degasser in the convex supply pipe, it is possible to suitably suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of poor molding of the optical fiber glass preform can be suitably suppressed.
（６）上記（５）の光ファイバ用ガラス母材の製造方法は、
　前記デガッサーが、前記供給管の鉛直方向の最上部または前記最上部よりも前記原料の供給流路における下流の部分に少なくとも一つ設けられていてもよい。
　ガスの溜まりやすい供給管の鉛直方向の最上部または前記最上部よりも前記原料の供給流路における下流の部分に少なくとも一つのデガッサーを設けることで供給管の内部のガスを好適に取り除くことができる。また、滞留したガスが短時間で一気に気化装置に流れ込むことによる原料の供給の不安定化を好適に抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を好適に抑制できる。 (6) The method for producing the optical fiber glass base material of (5) above,
At least one degasser may be provided at the top in the vertical direction of the supply pipe or at a portion downstream of the top in the raw material supply channel.
By providing at least one degasser at the top of the supply pipe in the vertical direction where gas tends to accumulate or at a portion downstream of the top in the supply channel of the raw material, the gas inside the supply pipe can be preferably removed. . In addition, it is possible to suitably suppress the instability of the raw material supply due to the stagnant gas flowing into the vaporizer at once in a short period of time. As a result, the occurrence of molding defects in the optical fiber glass preform can be suitably suppressed.
［本開示の実施形態の詳細］
　以下、本開示の光ファイバ用ガラス母材の製造装置および光ファイバ用ガラス母材の製造方法の実施形態の詳細を、図面を参照しつつ説明する。なお、以下に示す実施形態ではＭＭＤ法（多バーナー多層付け法）を基に説明するが、本開示はＭＭＤ法に限定されるものではなく、ＯＶＤ法（外付け法）やＶＡＤ法（気相軸付け法）にも適用可能である。 [Details of the embodiment of the present disclosure]
Hereinafter, details of embodiments of an apparatus for manufacturing an optical fiber glass preform and a method for manufacturing an optical fiber glass preform according to the present disclosure will be described with reference to the drawings. In addition, although the embodiment shown below will be described based on the MMD method (multi-burner multilayer method), the present disclosure is not limited to the MMD method, and the OVD method (external method) and the VAD method (vapor phase method). It is also applicable to the shaft attachment method).
　図１は、実施形態に係る光ファイバ用ガラス母材８の製造装置１００の構成図である。製造装置１００は、タンク１０と、供給管４０と、供給装置２０と、バーナー３０と、反応容器１３０と、を備える。図１における符号Ａが付された矢印は、鉛直方向を表す。タンク１０は鉛直方向下位のフロア１１０に設置され、供給装置２０、バーナー３０および反応容器１３０は鉛直方向上位のフロア１２０に設置されている。供給管４０は下位のフロア１１０と上位のフロア１２０とにわたって配管されている。 FIG. 1 is a configuration diagram of an apparatus 100 for manufacturing an optical fiber glass preform 8 according to an embodiment. The manufacturing apparatus 100 includes a tank 10 , a supply pipe 40 , a supply device 20 , a burner 30 and a reaction vessel 130 . The arrow labeled A in FIG. 1 indicates the vertical direction. The tank 10 is installed on the vertically lower floor 110 , and the feeder 20 , the burner 30 and the reaction vessel 130 are installed on the vertically upper floor 120 . The supply pipe 40 is laid across the lower floor 110 and the upper floor 120 .
　タンク１０は、ガラス微粒子６の基となる液体原料２を貯留する容器である。液体原料２としては、例えば四塩化ケイ素、シロキサン（例えばオクタメチルシクロテトラシロキサン）等が挙げられる。タンク１０において、液体原料２はガス４で加圧されて供給管４０に導入される。液体原料２を加圧するガスとしては、常温（２０℃）で液体に難溶であるＨｅなどの不活性ガスが用いられる。 The tank 10 is a container that stores the liquid raw material 2 that forms the basis of the glass fine particles 6 . Examples of the liquid raw material 2 include silicon tetrachloride and siloxane (eg, octamethylcyclotetrasiloxane). In tank 10 , liquid source 2 is pressurized with gas 4 and introduced into supply pipe 40 . As the gas for pressurizing the liquid raw material 2, an inert gas such as He that is sparingly soluble in liquid at room temperature (20° C.) is used.
　供給管４０は、液体原料２をバーナー３０へ導く管である。供給管４０は、バーナー３０と連結されている。供給管４０には、バーナー３０と連結される部分の直前の位置に、供給装置２０が設けられている。図１においては、一例として、５つのバーナー３０と５つの供給装置２０が示されている。供給管４０は、タンク１０と供給装置２０との間で５つに分岐している。分岐したそれぞれの供給管４０に供給装置２０が設けられている。 The supply pipe 40 is a pipe that guides the liquid raw material 2 to the burner 30 . The supply pipe 40 is connected with the burner 30 . The supply device 20 is provided on the supply pipe 40 at a position immediately before the portion connected to the burner 30 . In FIG. 1, five burners 30 and five feeders 20 are shown by way of example. The supply pipe 40 branches into five between the tank 10 and the supply device 20 . A supply device 20 is provided in each of the branched supply pipes 40 .
　供給管４０は、上流から下流に向かって、鉛直方向上方に延びてから鉛直方向下方に延びている。詳細には、供給管４０は、上位のフロア１２０の上部まで延びた後、供給装置２０の位置まで段階的に鉛直方向下方に延びる。供給管４０の鉛直方向の最上部４４には、デガッサー４２が設けられている。デガッサー４２は脱気膜により液体中のガスを除去する装置である。詳細には、デガッサー４２は供給管４０の間に接続されてオンラインで液体原料２中のガスを除去する。なお、本開示における凸型の配管の態様は、厳密に直角に曲がる配管の態様のみを指すものではなく、鈍角や鋭角で曲がる配管の態様や湾曲した配管の態様で鉛直方向上方に供給管４０が突き出るものも含む。また、本開示における凸型の配管の態様は、供給管が鉛直方向に対して傾斜して延びる部分を含む配管の態様も含む。またデガッサー４２は、供給管４０の最上部４４以外にも、最上部４４よりも液体原料２の供給流路における下流の部分４６に設けられていてもよい。 The supply pipe 40 extends vertically upward and then vertically downward from upstream to downstream. Specifically, the supply pipe 40 extends to the top of the upper floor 120 and then extends vertically downward in steps to the position of the supply device 20 . A degasser 42 is provided at a vertical uppermost portion 44 of the supply pipe 40 . A degasser 42 is a device that removes gas from a liquid using a degassing membrane. Specifically, the degasser 42 is connected between the supply pipes 40 to remove gas in the liquid source 2 on-line. It should be noted that the aspect of the convex pipe in the present disclosure does not refer only to the aspect of the pipe that bends at a strictly right angle, but the aspect of the pipe that bends at an obtuse angle or an acute angle, or the aspect of the curved pipe that vertically extends the supply pipe 40 upward. Including those that protrude. In addition, the aspect of convex piping in the present disclosure also includes the aspect of piping including a portion in which the supply pipe extends obliquely with respect to the vertical direction. Further, the degasser 42 may be provided at a portion 46 downstream of the uppermost portion 44 of the supply pipe 40 in the supply channel of the liquid raw material 2 , instead of the uppermost portion 44 .
　供給装置２０は、例えば供給部２２と、気化装置２４と、コントロールバルブ２６と、マスフローメーター（ＭＦＭ）２８と、を備える。これらは液体原料２の供給流路における上流からＭＦＭ２８、コントロールバルブ２６、気化装置２４、供給部２２、の順に配置されている。ＭＦＭ２８は、液体原料２の供給流量を測定する装置である。コントロールバルブ２６は、気化装置２４への液体原料２の供給流量を制御するバルブである。コントロールバルブ２６は、ＭＦＭ２８が検知した液体原料２の供給流量に基づいてバルブの開度を制御するように構成されている。気化装置２４は、液体原料２に窒素などのキャリアガスを導入して、液体原料２を気化（ミスト状態に）する装置である。供給部２２は、ミスト状態の液体原料２を、バーナー３０に供給する部分である。 The supply device 20 includes, for example, a supply section 22, a vaporization device 24, a control valve 26, and a mass flow meter (MFM) 28. These are arranged in the order of the MFM 28 , the control valve 26 , the vaporizer 24 and the supply section 22 from the upstream in the supply flow path of the liquid raw material 2 . The MFM 28 is a device that measures the supply flow rate of the liquid raw material 2 . The control valve 26 is a valve that controls the supply flow rate of the liquid raw material 2 to the vaporizer 24 . The control valve 26 is configured to control the degree of opening of the valve based on the supply flow rate of the liquid raw material 2 detected by the MFM 28 . The vaporizer 24 is a device that introduces a carrier gas such as nitrogen into the liquid raw material 2 to vaporize the liquid raw material 2 (into a mist state). The supply part 22 is a part that supplies the liquid raw material 2 in a mist state to the burner 30 .
　バーナー３０は、反応容器１３０の内部で、気化された原料を火炎中において熱分解酸化反応させることでガラス微粒子６を生成する部材である。バーナー３０は、生成されたガラス微粒子６を、軸周りに回転する出発ロッド１３２に噴きつけて堆積させて、光ファイバ用ガラス母材８を製造する。バーナー３０には原料ガスの他、火炎形成ガスとしてＨ２やＯ２等、バーナーシールガスとしてＮ２やＡｒ等の不活性ガスが供給される。 The burner 30 is a member that generates the glass microparticles 6 by thermally decomposing and oxidizing the vaporized raw material in a flame inside the reaction vessel 130 . The burner 30 sprays and deposits the generated glass fine particles 6 on the starting rod 132 rotating about the axis, thereby manufacturing the optical fiber glass preform 8 . In addition to the raw material gas, the burner 30 is supplied with a flame forming gas such as H 2 and O 2 and an inert gas such as N 2 and Ar as a burner sealing gas.
　反応容器１３０は、例えばバーナー３０と、端部加熱バーナー３２と、排気部１３４と、を備える。例えば、反応容器１３０の内部には、光ファイバ用ガラス母材８を製造する際に出発ロッド１３２が所定の位置に配置される。上述の様に、反応容器１３０においてバーナー３０により生成されたガラス微粒子６が出発ロッド１３２に噴きつけられて、光ファイバ用ガラス母材８が製造される。排気部１３４は、出発ロッド１３２および光ファイバ用ガラス母材８に付着しなかったガラス微粒子６などを反応容器１３０内のガスとともに反応容器１３０の外部に排出する部分である。端部加熱バーナー３２は、光ファイバ用ガラス母材８の上下の端部を加熱するバーナーである。図１においては、一例として、２つの端部加熱バーナー３２が示されている。２つの端部加熱バーナー３２は、５つのバーナー３０を上下で挟むように配置されている。 The reaction vessel 130 includes, for example, a burner 30, an end heating burner 32, and an exhaust section 134. For example, inside the reaction vessel 130, a starting rod 132 is arranged at a predetermined position when manufacturing the optical fiber glass preform 8. As shown in FIG. As described above, the glass particles 6 generated by the burner 30 in the reaction vessel 130 are sprayed onto the starting rod 132 to produce the optical fiber glass preform 8 . The exhaust part 134 is a part for discharging the glass particles 6 that have not adhered to the starting rod 132 and the optical fiber glass base material 8 to the outside of the reaction vessel 130 together with the gas inside the reaction vessel 130 . The end heating burners 32 are burners for heating the upper and lower ends of the optical fiber glass preform 8 . In FIG. 1, two end heating burners 32 are shown by way of example. The two end heating burners 32 are arranged so as to sandwich the five burners 30 from above and below.
　続いて、上記の製造装置１００を用いた本実施形態の光ファイバ用ガラス母材の製造方法を説明する。当該製造方法では、供給管４０にデガッサー４２が設けられている製造装置１００を用いる。そして、供給装置２０を介してバーナー３０に気化した原料を供給し、当該原料を火炎中において熱分解酸化反応させることでガラス微粒子６を生成する。そして、生成されたガラス微粒子６を、軸周りに回転する出発ロッド１３２に噴きつけて堆積させて、光ファイバ用ガラス母材８を製造する。 Next, a method for manufacturing an optical fiber glass preform according to the present embodiment using the manufacturing apparatus 100 described above will be described. In this manufacturing method, a manufacturing apparatus 100 in which a degasser 42 is provided in a supply pipe 40 is used. Then, the vaporized raw material is supplied to the burner 30 via the supply device 20, and the glass microparticles 6 are generated by thermally decomposing and oxidizing the raw material in the flame. Then, the generated glass particles 6 are sprayed and deposited on the starting rod 132 rotating about the axis to manufacture the optical fiber glass preform 8 .
　ところで、液体原料の供給流量が急峻に変動すると、気化装置に供給される液体原料が増減を繰り返す現象（ハンチング現象）が発生する場合がある。ハンチング現象が発生すると、製造されるガラス母材に成形不良が発生するおそれがある。 By the way, if the supply flow rate of the liquid raw material fluctuates sharply, a phenomenon (hunting phenomenon) may occur in which the liquid raw material supplied to the vaporizer repeats an increase and decrease. When the hunting phenomenon occurs, there is a risk that the manufactured glass base material will have a molding defect.
　Ｈｅなどのガスは、一般的に液体に難溶であるが、液体原料がＨｅなどのガスによって加圧されて供給管に導入される際、当該ガスはヘンリーの法則に従ってその一部が液体の原料に溶け込む。そして供給管での圧力損失などにより液体原料にかかる圧力が低下すると、溶けたガスが気泡として湧き出す。この湧き出したガスが供給管内で滞留し、滞留したガスが供給装置に短時間で一気に流れ込むと、ハンチング現象を起こす場合がある。例えばＭＦＭを採用している場合に滞留したガスがＭＦＭに短時間で一気に流れ込むと、ＭＦＭが検知する流量が０となり、コントロールバルブの開度が増大し、ハンチング現象を起こす。その結果、液体原料が短時間で一気に気化装置に流れ込み、大量の原料ガスを噴出することになる。このようなハンチング現象が起きると、製造される光ファイバ用ガラス母材に成形不良が発生するおそれがある。 Gases such as He are generally poorly soluble in liquids. Melt into raw materials. When the pressure applied to the liquid raw material drops due to pressure loss in the supply pipe or the like, the dissolved gas gushes out as bubbles. If this bubbling gas stays in the supply pipe and the staying gas flows into the supply device at once in a short period of time, a hunting phenomenon may occur. For example, when an MFM is employed, if stagnant gas flows into the MFM at once in a short period of time, the flow rate detected by the MFM becomes 0, the opening of the control valve increases, and a hunting phenomenon occurs. As a result, the liquid raw material flows into the vaporizer at once in a short time, and a large amount of raw material gas is jetted out. If such a hunting phenomenon occurs, there is a possibility that the manufactured optical fiber glass preform may have a molding defect.
　本実施形態の製造装置１００および製造方法によれば、供給管４０にデガッサー４２が設けられていることで供給管４０の内部のガスを取り除くことができ、滞留したガスが短時間で一気に気化装置２４に流れ込むことによる原料の供給の不安定化を抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を抑制できる。 According to the manufacturing apparatus 100 and the manufacturing method of the present embodiment, the degasser 42 is provided in the supply pipe 40, so that the gas inside the supply pipe 40 can be removed, and the stagnant gas is vaporized at once in a short time. It is possible to suppress the instability of the raw material supply due to the raw material flowing into 24 . As a result, the occurrence of molding defects in the optical fiber glass preform can be suppressed.
　また、上流から下流に向かって、鉛直方向上方に延びてから鉛直方向下方に延びている供給管では、供給管の鉛直方向の最上部にガスが滞留しやすい。本実施形態の製造装置１００および製造方法によれば、凸型の形状を有している供給管４０にデガッサー４２を設けることで、滞留したガスが短時間で一気に気化装置２４に流れ込むことによる原料の供給の不安定化を好適に抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を好適に抑制できる。 In addition, in a supply pipe that extends vertically upward and then vertically downward from upstream to downstream, gas tends to stay at the top of the supply pipe in the vertical direction. According to the manufacturing apparatus 100 and the manufacturing method of the present embodiment, by providing the degasser 42 in the supply pipe 40 having a convex shape, the stagnant gas flows into the vaporization device 24 at once in a short time, thereby degassing the raw material. destabilization of the supply of can be suitably suppressed. As a result, the occurrence of poor molding of the optical fiber glass preform can be suitably suppressed.
　なお、凸型以外の形状を有した供給管にデガッサー４２を設けることでも原料の供給の不安定化を抑制できる。その一方で、上述の様に凸型の形状を有する供給管４０では最上部４４にガスが滞留しやすいので、供給管４０にデガッサー４２を設けることで原料の供給の不安定化をより好適に抑制できる。 It should be noted that destabilization of raw material supply can also be suppressed by providing a degasser 42 in a supply pipe having a shape other than a convex shape. On the other hand, since gas tends to stay in the uppermost portion 44 of the supply pipe 40 having a convex shape as described above, the degasser 42 is provided in the supply pipe 40 to prevent the supply of the raw material from becoming unstable. can be suppressed.
　また、本実施形態の製造装置１００および製造方法によれば、ガスの溜まりやすい供給管４０の鉛直方向の最上部４４または最上部４４よりも液体原料２の供給流路における下流の部分４６に少なくとも一つのデガッサー４２を設けることで、供給管４０の内部のガスを好適に取り除くことができ、滞留したガスが短時間で一気に気化装置２４に流れ込むことによる原料の供給の不安定化を好適に抑制できる。これにより、光ファイバ用ガラス母材の成形不良の発生を好適に抑制できる。 In addition, according to the manufacturing apparatus 100 and the manufacturing method of the present embodiment, at least the uppermost portion 44 in the vertical direction of the supply pipe 40 where gas tends to accumulate or the portion 46 downstream of the uppermost portion 44 in the supply channel of the liquid raw material 2 is at least By providing one degasser 42, the gas inside the supply pipe 40 can be preferably removed, and the instability of the raw material supply due to the stagnant gas flowing into the vaporizer 24 in a short period of time can be suppressed. can. As a result, the occurrence of poor molding of the optical fiber glass preform can be suitably suppressed.
　また、液体原料２として、四塩化ケイ素やシロキサンを例示したが、シロキサンは四塩化ケイ素と比べて沸点が高く気化させにくいため液体状態での供給区間がより長い必要がある。そのため、シロキサンを原料とする場合に本開示を適用すると、より好適にハンチング現象の発生を抑制できる。 In addition, silicon tetrachloride and siloxane were exemplified as the liquid raw material 2, but since siloxane has a higher boiling point than silicon tetrachloride and is difficult to vaporize, it is necessary to supply it in a liquid state for a longer period. Therefore, if the present disclosure is applied when siloxane is used as a raw material, the occurrence of the hunting phenomenon can be suppressed more appropriately.
　また、供給管４０の配管としては、外径が４ｍｍから１０ｍｍ、内径が３ｍｍから９ｍｍ程度のものを用いることができる。配管の内径が３ｍｍより小さくなると圧損が大きくなり、内径が９ｍｍより大きくなると、配管内の空洞により、気泡が増加しやすくなる。 Also, as the pipe of the supply pipe 40, a pipe having an outer diameter of 4 mm to 10 mm and an inner diameter of about 3 mm to 9 mm can be used. When the inner diameter of the pipe is smaller than 3 mm, the pressure loss increases, and when the inner diameter is larger than 9 mm, air bubbles tend to increase due to cavities in the pipe.
　ここで、デガッサー４２の有無によるハンチング現象への影響について検証した結果を示す。表１は、凸型の形状を有する供給管４０にデガッサー４２を設けた場合と、設けなかった場合の、ハンチングの有無を示す表である。デガッサー４２を設けた場合については、デガッサー４２を供給管４０の最上部に設けた場合と、供給管４０の入口部に設けた場合について、ハンチングの有無を調べた。なお、供給管４０はテフロン（登録商標）製で、配管径が、内径４ｍｍ、外径６ｍｍのものを使用した。この供給管４０に、液体ガラス原料を、設定供給量を５０ｇ／分として供給した。 Here, the result of verifying the influence of the presence or absence of the degasser 42 on the hunting phenomenon will be shown. Table 1 shows the presence or absence of hunting when the supply pipe 40 having a convex shape is provided with the degasser 42 and when it is not provided. With respect to the case where the degasser 42 was provided, the presence or absence of hunting was examined for the case where the degasser 42 was provided at the top of the supply pipe 40 and the case where the degasser 42 was provided at the inlet portion of the supply pipe 40 . The supply pipe 40 was made of Teflon (registered trademark) and had an inner diameter of 4 mm and an outer diameter of 6 mm. A liquid glass raw material was supplied to the supply pipe 40 at a set supply amount of 50 g/min.
　「最上部」とは、「凸型の形状を有する配管で一番高さが高い位置」であり、表１における「デガッサーを最上部に導入」は、「最上部」にデガッサーの配管を接続した場合の結果を示している。また、「入口部」とは、「凸型の形状を有する配管の最上部の位置から配管長で１ｍ以上離れた上流側の位置」であり、表１における「デガッサーを入口部に導入」は、「入口部」にデガッサーの配管を接続した場合の結果を示している。 "Top" is "the highest position in the pipe having a convex shape", and "introducing the degasser to the top" in Table 1 means that the degasser pipe is connected to the "top" The results are shown when In addition, the "inlet part" is "a position on the upstream side separated by a pipe length of 1 m or more from the uppermost position of the pipe having a convex shape", and "Introducing the degasser to the inlet part" in Table 1 , shows the results when the degasser pipe is connected to the "inlet".
　表１における圧力差ΔＰとは、製造装置１００のタンク１０における液体原料２へのガス４の供給圧力をＰ１とし、製造装置１００の気化装置２４に供給される直前の液体原料２の圧力をＰ２とした時の、Ｐ１とＰ２との差であり、ΔＰ＝Ｐ１－Ｐ２で表される。圧力差ΔＰを変えながら、ＭＦＭの流量変動を観察することにより、ハンチング現象の有無を判断した。 The pressure difference ΔP in Table 1 means that P1 is the supply pressure of the gas 4 to the liquid source 2 in the tank 10 of the manufacturing apparatus 100, and P2 is the pressure of the liquid source 2 immediately before being supplied to the vaporizer 24 of the manufacturing apparatus 100. is the difference between P1 and P2 when .DELTA.P=P1-P2. The presence or absence of the hunting phenomenon was determined by observing the MFM flow rate fluctuation while changing the pressure difference ΔP.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
　表１の結果から、デガッサー４２を設けない場合と比較して、デガッサー４２を設けた場合には、圧力差ΔＰが大きい時のハンチング現象の発生が抑制されていることがわかる。また、デガッサー４２を供給管４０の入口部に設けた場合と比較して、デガッサー４２を供給管４０の最上部に設けた場合には、ハンチング現象の発生を抑制する効果が高くなることがわかる。なお、供給管４０の最上部よりも下流側にデガッサー４２を設けた場合も、最上部に設けた場合と同様に、デガッサー４２を供給管４０の入口部に設けた場合と比較して、ハンチング現象の発生を抑制する効果が高くなる。 From the results in Table 1, it can be seen that the occurrence of the hunting phenomenon when the pressure difference ΔP is large is suppressed when the degasser 42 is provided, compared to when the degasser 42 is not provided. Further, it can be seen that the effect of suppressing the occurrence of the hunting phenomenon is enhanced when the degasser 42 is provided at the top of the supply pipe 40 as compared with the case where the degasser 42 is provided at the inlet of the supply pipe 40. . When the degasser 42 is provided downstream of the uppermost portion of the supply pipe 40, hunting is more likely to occur than when the degasser 42 is provided at the inlet portion of the supply pipe 40, as in the case of providing the degasser 42 at the uppermost portion. The effect of suppressing the occurrence of the phenomenon is enhanced.
　以上、特定の実施形態に基づいて本開示を説明したが、本発明はこれらの例示に限定されるものではなく、請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 As described above, the present disclosure has been described based on specific embodiments, but the present invention is not limited to these exemplifications, and is indicated by the scope of the claims. is intended to include changes to
　２：液体原料
　４：ガス
　６：ガラス微粒子
　８：光ファイバ用ガラス母材
　１０：タンク
　２０：供給装置
　２２：供給部
　２４：気化装置
　２６：コントロールバルブ
　２８：マスフローメーター
　３０：バーナー
　３２：端部加熱バーナー
　４０：供給管
　４２：デガッサー
　４４：最上部
　４６：下流の部分
　１００：光ファイバ用ガラス母材の製造装置
　１１０：下位のフロア
　１２０：上位のフロア
　１３０：反応容器
　１３２：出発ロッド
　１３４：排気部 2: liquid raw material 4: gas 6: fine glass particles 8: glass base material for optical fiber 10: tank 20: supply device 22: supply unit 24: vaporization device 26: control valve 28: mass flow meter 30: burner 32: edge heating Burner 40: Supply pipe 42: Degasser 44: Uppermost part 46: Downstream part 100: Optical fiber glass preform manufacturing apparatus 110: Lower floor 120: Upper floor 130: Reaction vessel 132: Departure rod 134: Exhaust part

Claims (6)

  1. 　液体の原料をガスで加圧するタンクと、加圧された前記原料を気化させる気化装置と、前記気化装置で気化された前記原料を噴出させてガラス微粒子を形成するバーナーと、前記タンクで加圧された前記原料を前記気化装置に供給する供給管と、を備え、前記供給管に、前記供給管内に滞留したガスを除去するデガッサーが設けられている、光ファイバ用ガラス母材の製造装置。 A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. and a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe.
  2. 　前記供給管が、上流から下流に向かって、鉛直方向上方に延びてから鉛直方向下方に延びている、請求項１に記載の光ファイバ用ガラス母材の製造装置。 The apparatus for manufacturing an optical fiber glass preform according to claim 1, wherein the supply pipe extends vertically upward and then vertically downward from upstream to downstream.
  3. 　前記デガッサーが、前記供給管の鉛直方向の最上部または前記最上部よりも前記原料の供給流路における下流の部分に少なくとも一つ設けられている、請求項２に記載の光ファイバ用ガラス母材の製造装置。 3. The optical fiber glass preform according to claim 2, wherein at least one degasser is provided at the uppermost part of the supply pipe in the vertical direction or at a portion downstream of the uppermost part in the supply channel of the raw material. manufacturing equipment.
  4. 　液体の原料をガスで加圧するタンクと、加圧された前記原料を気化させる気化装置と、前記気化装置で気化された前記原料を噴出させてガラス微粒子を形成するバーナーと、前記タンクで加圧された前記原料を前記気化装置に供給する供給管と、を備え、前記供給管に、前記供給管内に滞留したガスを除去するデガッサーが設けられている、光ファイバ用ガラス母材の製造装置を用いる光ファイバ用ガラス母材の製造方法。 A tank for pressurizing a liquid raw material with gas, a vaporizer for vaporizing the pressurized raw material, a burner for ejecting the raw material vaporized by the vaporizer to form glass fine particles, and pressurized by the tank. a supply pipe for supplying the vaporized raw material to the vaporizer, wherein the supply pipe is provided with a degasser for removing gas accumulated in the supply pipe. A method for producing an optical fiber glass preform used.
  5. 　前記供給管が、上流から下流に向かって、鉛直方向上方に延びてから鉛直方向下方に延びている、請求項４に記載の光ファイバ用ガラス母材の製造方法。 The method for manufacturing an optical fiber glass preform according to claim 4, wherein the supply pipe extends vertically upward and then vertically downward from upstream to downstream.
  6. 　前記デガッサーが、前記供給管の鉛直方向の最上部または前記最上部よりも前記原料の供給流路における下流の部分に少なくとも一つ設けられている、請求項５に記載の光ファイバ用ガラス母材の製造方法。 6. The optical fiber glass preform according to claim 5, wherein at least one degasser is provided at the uppermost part of the supply pipe in the vertical direction or at a portion downstream of the uppermost part in the supply channel of the raw material. manufacturing method.
PCT/JP2022/033929 2021-09-10 2022-09-09 Device and method for manufacturing glass preform for optical fiber WO2023038124A1 (en)

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JPH04110462A (en) * 1989-12-22 1992-04-10 Corning Inc Flash evaporating apparatus, flash evaporator and method of forming preform by flash evaporator
JPH0781965A (en) * 1993-07-22 1995-03-28 Sumitomo Electric Ind Ltd Gas producer, method for producing optical waveguide and optical fiber preform and device therefor
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