WO2021193567A1 - Four de tréfilage de fibre optique et procédé de production de fibre optique - Google Patents

Four de tréfilage de fibre optique et procédé de production de fibre optique Download PDF

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Publication number
WO2021193567A1
WO2021193567A1 PCT/JP2021/011793 JP2021011793W WO2021193567A1 WO 2021193567 A1 WO2021193567 A1 WO 2021193567A1 JP 2021011793 W JP2021011793 W JP 2021011793W WO 2021193567 A1 WO2021193567 A1 WO 2021193567A1
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WO
WIPO (PCT)
Prior art keywords
optical fiber
gas
drawing furnace
lower chamber
protective tube
Prior art date
Application number
PCT/JP2021/011793
Other languages
English (en)
Japanese (ja)
Inventor
巌 岡崎
惣太郎 井田
仁広 森本
Original Assignee
住友電気工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友電気工業株式会社 filed Critical 住友電気工業株式会社
Priority to JP2022510503A priority Critical patent/JPWO2021193567A1/ja
Priority to CN202180023039.3A priority patent/CN115335337A/zh
Publication of WO2021193567A1 publication Critical patent/WO2021193567A1/fr

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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
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/029—Furnaces therefor

Definitions

  • the present disclosure relates to an optical fiber drawing furnace and an optical fiber manufacturing method.
  • This application claims priority based on Japanese Patent Application No. 2020-051898 filed on March 23, 2020, and incorporates all the contents described in the above application.
  • Patent Document 1 discloses an optical fiber manufacturing apparatus in which helium gas is supplied into a drawing furnace to draw an optical fiber, and the drawn optical fiber is cooled in argon gas in a cooling pipe connected to the drawing furnace. Has been done.
  • the optical fiber wire drawing furnace houses a core tube into which a glass base material for optical fiber is inserted, a heater for heating the glass base material for optical fiber from the outside, and the core tube inside.
  • the furnace body the lower chamber arranged below the core tube, the protective tube arranged below the lower chamber, and the in-core gas introduction in which the inert gas flows into the core tube from above to below.
  • An optical fiber wire drawing furnace provided with a portion, which has a gas introduction port for introducing a predetermined gas into the protective tube, and has a radial cross-sectional area of an internal space on the upper side of the gas introduction port. It has a smaller constriction than the lower chamber.
  • optical fiber manufacturing method is a method of manufacturing an optical fiber using the above-mentioned optical fiber drawing furnace.
  • FIG. 1 is a schematic view of an optical fiber drawing furnace according to an embodiment of the present disclosure.
  • FIG. 2A is a diagram showing another example of the gas inlet of the protective tube.
  • FIG. 2B is a diagram showing still another example of the gas inlet of the protective tube.
  • FIG. 3A is a schematic view of an optical fiber drawing furnace according to another embodiment of the present disclosure.
  • FIG. 3B is a cross-sectional view taken along the line 3B-3B of FIG. 3A.
  • the drawing furnace is provided with a lower chamber (lower chimney) and a protective tube below the lower chamber, and inside the lower chamber and the protective tube so that the glass diameter of the optical fiber (glass fiber portion) is stable.
  • the optical fiber is protected by.
  • SiO 2 gas or the like since SiO 2 gas or the like is generated from the high temperature glass base material, the SiO 2 gas or the like cools in the lower chamber and silica (SiO 2 ) powder is generated.
  • Silica powder floats in the inert gas flowing into the drawing furnace, accumulates in the drawing furnace, is discharged to the outside of the furnace from the lower chamber of the drawing furnace or the outlet of the protective pipe, or comes into contact with the optical fiber. Or collide.
  • the strength of the optical fiber decreases.
  • the frequency of disconnection of the optical fiber increases in the fiber screening test (proof test) performed after the drawing is completed, and the productivity may decrease.
  • the temperature of the drawing furnace In order to reduce the amount of silica powder generated from the glass base material, there is a method of lowering the temperature of the drawing furnace.
  • it is difficult to simply lower the drawing furnace temperature because the drawing furnace temperature affects the desired glass tension during drawing and also depends on the size of the base metal and the like.
  • the optical fiber drawing furnace houses (1) a core tube into which a glass base material for optical fiber is inserted, a heater for heating the glass base material for optical fiber from the outside, and the core tube inside.
  • the furnace body the lower chamber arranged below the core tube, the protective tube arranged below the lower chamber, and the in-core gas introduction in which the inert gas flows into the core tube from above to below.
  • An optical fiber wire drawing furnace provided with a portion, which has a gas introduction port for introducing a predetermined gas into the protective tube, and has a radial cross-sectional area of an internal space on the upper side of the gas introduction port.
  • the concentration of silica powder per gas flow rate in the protective tube can be reduced, so that the probability that the silica powder comes into contact with or collides with the optical fiber is reduced, and the occurrence of a decrease in the strength of the optical fiber can be suppressed.
  • the protective tube may be connected below the lower chamber. As a result, the optical fiber is not exposed to the outside air between the lower chamber and the protective tube, and the glass diameter is stabilized.
  • the gas inlet is provided from the center to the upper side of the protective pipe.
  • the concentration of silica powder per gas flow rate can be reduced in most of the inside of the protective tube, so that the probability that the silica powder comes into contact with or collides with the optical fiber is reduced, and the occurrence of a decrease in the strength of the optical fiber is suppressed. Can be done.
  • the lower part of the lower chamber may have a gas vent hole for discharging the inert gas in the lower chamber to the outside.
  • Gas may be forcibly exhausted from the gas vent hole. As a result, the probability that the silica powder comes into contact with or collides with the optical fiber is further reduced, and the occurrence of a decrease in the strength of the optical fiber can be suppressed.
  • the gas introduction port is provided at the upper end of the protective pipe.
  • the concentration of the silica powder can be rapidly reduced in the protective tube over almost the entire length of the protective tube, and the probability of the silica powder coming into contact with or colliding with the optical fiber is further reduced.
  • the predetermined gas may be argon, nitrogen, or air.
  • the gas introduction ports may be provided at equal intervals in the circumferential direction of the protective pipe. As a result, the gas evenly hits around the optical fiber, so that the optical fiber can be prevented from shaking in the protective tube, which affects the fluctuation of the optical fiber diameter and the bending of the fiber due to the non-uniformity of temperature (fiber curl). Can be suppressed.
  • the gas introduction port may be provided downward so as to introduce the predetermined gas downward into the inside of the protective pipe. As a result, turbulence of the gas flow in the protective tube can be suppressed.
  • the gas introduction port may be obliquely downward and may face in a direction along the wall surface of the protective pipe so as to introduce the predetermined gas into the protective pipe in a spiral shape. This makes it easier to separate the silica powder from the periphery of the fiber. Moreover, the turbulence of the gas flow around the fiber can be reduced.
  • the optical fiber manufacturing method is (11) a method of manufacturing an optical fiber using the above-mentioned optical fiber drawing furnace.
  • the concentration of silica powder per gas flow rate in the protective tube can be reduced, so that the probability that the silica powder comes into contact with or collides with the optical fiber is reduced, and the occurrence of a decrease in the strength of the optical fiber can be suppressed.
  • FIG. 1 is a schematic view of an optical fiber drawing furnace according to one aspect of the present disclosure.
  • the optical fiber wire drawing furnace (hereinafter referred to as “line drawing furnace”) 10 has a furnace main body 11, an upper chamber 12 provided above the furnace main body 11, and a lower chamber 13 provided below the furnace main body 11. ..
  • the upper chamber 12 and the lower chamber 13 have a hollow tube shape.
  • a heater 15 for heating and melting the glass base material 1 is arranged inside the furnace body 11, and a cylindrical core tube 14 is arranged so as to be surrounded by the heater 15.
  • a heat insulating material 16 is provided between the heater 15 and the furnace body 11 so as to surround the heater 15 so that the heat from the heater 15 is not dissipated to the outside.
  • the heater may be one using induction heating.
  • a protective tube 20, which will be described in detail later, is arranged below the lower chamber 13, a protective tube 20, which will be described in detail later, is arranged.
  • the protective tube 20 is preferably in close contact with and connected to the lower chamber 13, but there may be a gap between the protective tube 20 and the lower chamber 13 to some extent. Further, in the present embodiment, the lower chamber 13 and the protective tube 20 are described one by one, but each of them may be divided into a plurality of parts or may be integrated with each other.
  • the glass base material 1 is suspended in the core tube 14 by a base material suspension mechanism (not shown), the lower part of the glass base material 1 is heated by the heater 15, and the lower end portion of the molten glass base material 1 is drawn.
  • This is a step of melting and hanging the optical fiber (glass fiber portion) 2 from the glass fiber (glass fiber portion) 2 so that the optical fiber 2 taken out from below the drawing furnace 10 has a predetermined outer diameter.
  • Nitrogen introduced from the in-core gas introduction unit 17 or an inert gas such as helium or argon is supplied into the core tube 14 from above to below. Since the inside of the core tube 14 is under an inert gas atmosphere, it is possible to prevent oxidation of the core tube 14 and the like, which are carbon components, and to keep the inside clean.
  • the inert gas introduced into the core tube 14 is heated to about 2000 ° C. or higher in the core tube 14. Then, a part of the heated inert gas is discharged to the outside together with the optical fiber 2 through the space inside the core tube 14 through the lower chamber 13 and the protective tube 20 by the downflow.
  • the lower chamber 13 and the protective tube 20 are connected to each other, and the narrowed portion 13a and the protective tube 20 of the lower chamber 13 whose internal space cross-sectional area is smaller than that of the lower chamber 13 are narrowed at the connecting portion, respectively.
  • the portion 20a is formed.
  • a gas introduction port 21 is provided directly below the narrowed portion 20a of the protective tube 20.
  • the gas introduction ports 21 are provided at equal intervals, for example, at four locations in the circumferential direction of the protective tube 20.
  • the narrowed portion 13a and the narrowed portion 20a make the pressure inside the core tube 14 and the lower chamber 13 above the narrowed portions 13a and 20a more positive than the pressure inside the protective tube 20 below the narrowed portions 13a and 20a. It is for keeping pressure.
  • the constriction portion is not limited to being provided at the connecting portion between the lower chamber 13 and the protective pipe 20, but is provided only at one of the lower chamber 13 and the protective pipe 20. You may.
  • the gas introduction port 21 is preferably provided at the upper end portion of the protective pipe 20 (including not only the upper end but also the vicinity of the upper end), but the gas introduction port 21 may be provided from the center in the longitudinal direction to the upper side of the protective pipe 20.
  • a clean gas such as argon, nitrogen, or air, which is cheaper than helium, is introduced into the gas introduction port 21 from the outside.
  • the concentration of silica powder suspended in the inert gas in the drawing furnace 10 per unit gas flow rate is lowered in the protective tube 20 having the gas introduction port 21, so that the optical fiber 2 being drawn is drawn. Reduces the chance that the gas will come into contact with or collide with the silica powder.
  • the concentration of the silica powder in the protective tube 20 per gas flow rate is N / Q3, and the concentration of the silica powder suspended in the inert gas in the drawing furnace 10 per unit gas flow rate is set to the gas introduction port 21. It can be lowered in the protective tube 20 having the.
  • the pressure inside the lower chamber 13 is higher than the pressure inside the protective tube 20 below the narrowed portions 13a and 20a. Can be kept. As a result, the gas introduced from the gas introduction port 21 is suppressed from flowing to the lower chamber 13 side.
  • the probability that the silica powder comes into contact with or collides with the optical fiber 2 in the protective tube 20 can be reduced.
  • the silica powder contained in the gas flowing in the core tube 14 is quickly discharged to the outside from the inside of the protection tube 20 by the gas introduced from the gas introduction port 21 of the protection tube 20.
  • the optical fiber 2 moves through the core tube 14, the lower chamber 13, and the protective tube 20 at a constant speed, but the concentration of silica powder per unit gas flow rate when passing through the protective tube 20 does not introduce gas. Since it is lower than that of the above, the probability of contact or collision of silica powder can be reduced as a whole, and the occurrence of a decrease in the strength of the optical fiber can be suppressed.
  • the silica powder concentration in the protective tube 20 below the gas introduction port 21 can be quickly reduced. Therefore, it is desirable to reduce the silica powder concentration in the entire length of the protective tube 20 by providing the gas introduction port 21 near the upper end of the protective tube 20. Further, it is desirable that the gas introduced into the protective tube 20 flows evenly from the circumferential direction of the optical fiber 2 so as not to shake the optical fiber 2.
  • FIG. 2A is a view showing another example of the gas inlet of the protective tube, and is a cross-sectional view in the length direction.
  • the plurality of gas introduction ports 21'provided in the protection pipe 20 are provided so as to be inclined obliquely downward toward the protection pipe 20. Therefore, the gas introduced into the protective pipe 20 from the gas introduction port 21'is introduced into the protective pipe 20 at a downward angle.
  • the gas introduced into the protective tube 20 flows smoothly in the traveling direction of the optical fiber 2, so that the turbulence of the gas flow is suppressed, and the influence on the diameter fluctuation of the optical fiber 2 and the influence on the fiber curl are affected. It is suppressed. Also in this embodiment, it is desirable that the gas introduced into the protective tube 20 flows evenly from the circumferential direction of the optical fiber 2.
  • FIG. 2B is a diagram showing still another example of the gas inlet of the protective tube, and is a cross-sectional view in the radial direction.
  • the plurality of gas introduction ports 21 "provided in the protection pipe 20 are provided so as to introduce the gas in the direction along the wall surface, not in the direction toward the center of the protection pipe 20, but diagonally downward.
  • the gas introduced into the protective tube 20 swirls along the inner wall of the protective tube 20, that is, flows in a spiral shape in the circumferential direction, and easily separates the silica powder from the periphery of the optical fiber 2.
  • the gas to be introduced into the protection pipe 20 may be flown from one gas introduction port or may be uniformly flown from a plurality of gas introduction ports 21 ”.
  • FIG. 3A is a schematic view of an optical fiber drawing furnace according to another aspect of the present disclosure.
  • FIG. 3B is a cross-sectional view taken along the line 3B-3B of FIG. 3A.
  • the present embodiment is different from the first to third embodiments in that a gas vent hole 13b that opens to the outside is provided below the lower chamber 13, but the other configurations are the same, so that they overlap. The description of the configuration to be performed will be omitted.
  • a plurality of degassing holes 13b are provided at equal intervals around the narrowed portion 13a provided below the lower chamber 13. From the gas vent hole 13b, a part of the inert gas flowing through the core tube 14 and the lower chamber 13 is discharged to the outside together with the silica powder.
  • the degassing hole 13b is configured to discharge the inert gas below the lower chamber 13, but is provided on the lower side surface of the lower chamber so as to discharge the inert gas to the side of the lower chamber. You may.
  • the core tube 14 contains N silica powders per liter of Q1 when the inert gas having a flow rate of Q1slm is flowing downward.
  • the concentration of silica powder per gas flow rate in the lower chamber 13 is N / Q1.
  • the inert gas of Q4slm is discharged to the outside from the gas vent hole 13b, the gas of (Q1-Q4) slm is introduced into the protective tube 20 from the lower chamber 13.
  • the concentration of silica powder per gas flow rate contained in the inert gas introduced into the protective tube 20 is the same as N / Q1, but the amount of silica powder entering the protective tube 20 per minute is N. It becomes ⁇ (1-Q4 / Q1).
  • Q4 + Q2) It becomes slm. Therefore, the concentration of silica powder in the protective tube 20 per gas flow rate is ⁇ N ⁇ (1-Q4 / Q1) ⁇ / Q5. Therefore, the concentration of the silica powder suspended in the inert gas in the protective tube 20 per unit gas flow rate can be lowered as compared with the first embodiment.
  • the gas introduced into the protective tube 20 can be introduced into the protective tube 20 at a downward angle, or the protective tube 20 can be introduced. It is desirable to introduce it so that it flows in a spiral direction in the circumferential direction along the inner wall of the. Further, in order to make the flow rate of the inert gas discharged to the outside from the gas vent hole 13b larger than the flow rate of the inert gas toward the protection tube 20, the inert gas in the lower chamber 13 is sucked from the gas vent hole 13b. However, it may be forcibly exhausted. By discharging the inert gas from the gas vent hole 13b to the outside in this way, it is possible to control the ratio of the gas flow rate towed by the optical fiber to the gas flow rate discharged from the gas vent hole.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

La présente invention concerne un four de tréfilage qui comprend : un tuyau de cœur de four dans lequel un matériau de base en verre pour fibre optique doit être inséré ; un corps de four qui loge à l'intérieur de celui-ci un dispositif de chauffage pour chauffer ledit matériau de base en verre pour une fibre optique depuis l'extérieur ; une chambre inférieure disposée au-dessous du tuyau central de four ; et un tuyau de protection disposé au-dessous de la chambre inférieure, un gaz inerte étant diffusé en continu de haut en bas à l'intérieur du tuyau central de four. En outre, le four de tréfilage comprend : un orifice d'introduction de gaz à travers lequel un gaz prescrit est introduit dans le tuyau de protection ; et une zone rétrécie qui est disposée sur le côté amont de l'orifice d'introduction de gaz et qui est pourvue d'un espace intérieur qui a une surface de section transversale orientée radialement plus petite que celle de la chambre inférieure.
PCT/JP2021/011793 2020-03-23 2021-03-22 Four de tréfilage de fibre optique et procédé de production de fibre optique WO2021193567A1 (fr)

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JP2022510503A JPWO2021193567A1 (fr) 2020-03-23 2021-03-22
CN202180023039.3A CN115335337A (zh) 2020-03-23 2021-03-22 光纤拉丝炉以及光纤制造方法

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JP2020051898 2020-03-23
JP2020-051898 2020-03-23

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000128566A (ja) * 1998-10-29 2000-05-09 Hitachi Cable Ltd 光ファイバの製造方法および製造装置
US20040050112A1 (en) * 2002-08-31 2004-03-18 Lg Cable Ltd. Furnace for drawing optical fiber preform to make optical fiber and method for drawing optical fiber using the same
JP2004250286A (ja) * 2003-02-20 2004-09-09 Sumitomo Electric Ind Ltd 光ファイバ線引装置及び線引方法
JP2006240930A (ja) * 2005-03-04 2006-09-14 Hitachi Cable Ltd 光ファイバ線引炉及び光ファイバの線引方法

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Publication number Priority date Publication date Assignee Title
JPS5913640A (ja) * 1982-07-09 1984-01-24 Nippon Telegr & Teleph Corp <Ntt> 光フアイバの製造方法
JPH059044A (ja) * 1991-06-26 1993-01-19 Furukawa Electric Co Ltd:The ハーメチツク被覆光フアイバーの製造方法及び製造装置
JP2760697B2 (ja) * 1992-04-03 1998-06-04 株式会社フジクラ 光ファイバ線引き炉
JPH08333130A (ja) * 1995-06-01 1996-12-17 Furukawa Electric Co Ltd:The 光ファイバ線引用加熱炉
EP1243568B1 (fr) * 1999-05-27 2013-03-06 Sumitomo Electric Industries, Ltd. Procede de production pour fibre optique
CN105948478A (zh) * 2016-06-20 2016-09-21 南京华信藤仓光通信有限公司 一种可降低氦气用量的光纤生产加热炉

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000128566A (ja) * 1998-10-29 2000-05-09 Hitachi Cable Ltd 光ファイバの製造方法および製造装置
US20040050112A1 (en) * 2002-08-31 2004-03-18 Lg Cable Ltd. Furnace for drawing optical fiber preform to make optical fiber and method for drawing optical fiber using the same
JP2004250286A (ja) * 2003-02-20 2004-09-09 Sumitomo Electric Ind Ltd 光ファイバ線引装置及び線引方法
JP2006240930A (ja) * 2005-03-04 2006-09-14 Hitachi Cable Ltd 光ファイバ線引炉及び光ファイバの線引方法

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JPWO2021193567A1 (fr) 2021-09-30
CN115335337A (zh) 2022-11-11

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