JPH06235828A - Heating furnace for drawing optical fiber preform - Google Patents
Heating furnace for drawing optical fiber preformInfo
- Publication number
- JPH06235828A JPH06235828A JP5022693A JP2269393A JPH06235828A JP H06235828 A JPH06235828 A JP H06235828A JP 5022693 A JP5022693 A JP 5022693A JP 2269393 A JP2269393 A JP 2269393A JP H06235828 A JPH06235828 A JP H06235828A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- heating furnace
- fiber preform
- temperature
- preform
- Prior art date
- Legal status (The legal status 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 status listed.)
- Pending
Links
Classifications
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2205/00—Fibre drawing or extruding details
- C03B2205/60—Optical fibre draw furnaces
- C03B2205/62—Heating means for drawing
- C03B2205/63—Ohmic resistance heaters, e.g. carbon or graphite resistance heaters
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2205/00—Fibre drawing or extruding details
- C03B2205/60—Optical fibre draw furnaces
- C03B2205/72—Controlling or measuring the draw furnace temperature
Landscapes
- 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)
- Glass Melting And Manufacturing (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は光ファイバ延伸用加熱炉
に関し、特に光ファイバ母材を真円に延伸できる加熱炉
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace for drawing an optical fiber, and more particularly to a heating furnace capable of drawing an optical fiber preform in a perfect circle.
【0002】[0002]
【従来の技術】光ファイバは通常、光ファイバ母材を加
熱炉で加熱、溶融しながら延伸、線引きして形成され
る。このような延伸用加熱炉(以下加熱炉と略記する場
合もある)は一般的に保守が比較的容易で熱的に安定性
の良いカーボンを用いた電気抵抗加熱炉が採用されてい
る。従来の加熱装置の一例の断面形状を図3に示す。ケ
ース(6)の中央部にある光ファイバ母材(1)の外周に
は、電源(5)により電気を供給することで自らの電気抵
抗で発熱するリング状のカーボンヒーター(2)の上端部
が電極(3)を介して取り付けられている。ケース(1)と
カーボンヒーター(2)との間にはカーボン、フェルト等
の断熱材(4)が環状に配置され、カーボンヒーター(2)
の熱がケース(6)の外側へ放熱するのを防いでいる。
〔文献:WIRE JOURNAL(APRIL 19
81)p86〜90〕2. Description of the Related Art An optical fiber is usually formed by heating and melting an optical fiber preform in a heating furnace while stretching and drawing. As such a drawing heating furnace (hereinafter sometimes abbreviated as a heating furnace), an electric resistance heating furnace using carbon, which is relatively easy to maintain and has good thermal stability, is generally adopted. A cross-sectional shape of an example of a conventional heating device is shown in FIG. On the outer circumference of the optical fiber preform (1) in the center of the case (6), the upper end of the ring-shaped carbon heater (2) that generates heat by its own electric resistance by supplying electricity from the power supply (5). Are attached via electrodes (3). An insulating material (4) such as carbon or felt is annularly arranged between the case (1) and the carbon heater (2).
This prevents the heat from radiating to the outside of the case (6).
[Reference: WIRE JOURNAL (APRIL 19
81) p86-90]
【0003】[0003]
【発明が解決しようとする課題】従来の加熱炉はカーボ
ンヒーターの周方向での断面積の変化や、その外側に環
状に配置された断熱材の厚みの不均一性により、光ファ
イバ母材の円周方向で温度が不均一となっていまい、延
伸されたファイバの非円率(本明細書において「非円率
(%)」は「非円率(%)=外径差/外径×100
(%)」の式で定義される)が悪くなるという問題があ
る。ファイバの非円は接続ロスを少なくするための重要
な要因であり、小さい方(即ち真円に近い断面)である
ほど望ましい。本発明は延伸後にその断面形状が真円に
近いファイバを得ることのできる光ファイバ母材延伸用
加熱炉を課題としてなされたものである。In the conventional heating furnace, due to the change in the cross-sectional area of the carbon heater in the circumferential direction and the nonuniformity of the thickness of the heat insulating material annularly arranged outside the carbon heater, The temperature is not uniform in the circumferential direction, and the non-circularity of the drawn fiber (in the present specification, "non-circularity (%)" means "non-circularity (%) = outer diameter difference / outer diameter x 100
(Defined by the formula (%)) becomes worse. The non-circular shape of the fiber is an important factor for reducing the splice loss, and the smaller one (that is, the cross section closer to a perfect circle) is more preferable. An object of the present invention is to provide a heating furnace for drawing an optical fiber preform capable of obtaining a fiber whose cross-sectional shape is close to a perfect circle after drawing.
【0004】[0004]
【課題を解決するための手段】上記課題を解決するため
の手段として、本発明は光ファイバ母材を加熱、溶融し
延伸する加熱炉において、独立した複数個のヒーターを
光ファイバ母材の外周にリング状に配置してなることを
特徴とする光ファイバ母材延伸用加熱炉加熱炉を提供す
る。本発明における特に好ましい実施態様として、上記
の独立した複数個のヒーターの温度を測定し円周方向で
同一温度となるよう制御する手段を有してなる上記光フ
ァイバ母材延伸用加熱炉を挙げることができる。本発明
における特に好ましい別の実施態様として、上記加熱、
溶融し延伸することにより延伸された光ファイバの位置
の測定手段及び該測定手段で得られた測定値により延伸
された光ファイバ位置を一定になるように上記の個々の
ヒーターの温度を制御する手段を有してなる上記光ファ
イバ母材延伸用加熱炉を挙げることができる。As a means for solving the above problems, the present invention is a heating furnace for heating, melting and stretching an optical fiber preform, in which a plurality of independent heaters are provided on the outer periphery of the optical fiber preform. Provided is a heating furnace for drawing an optical fiber preform, which is arranged in a ring shape. As a particularly preferred embodiment of the present invention, the heating furnace for drawing the optical fiber preform is provided which has means for measuring the temperatures of the plurality of independent heaters and controlling the temperatures to be the same in the circumferential direction. be able to. As another particularly preferred embodiment of the present invention, the above heating,
Means for measuring the position of the optical fiber drawn by melting and drawing, and means for controlling the temperature of the individual heaters so that the position of the drawn optical fiber becomes constant according to the measurement value obtained by the measuring means. The heating furnace for drawing the optical fiber preform can be mentioned.
【0005】[0005]
【作用及び実施例】本発明による光ファイバ母材延伸用
加熱炉を図を参照して説明する。図1は本発明の一実施
例の断面図であり、(1)は光ファイバ母材、(2)はカー
ボンヒーター、(4)は断熱材を示す。図1の例では4個
のカーボンヒーター(2)がそれぞれ電源(5)に接続さ
れ、光ファイバ母材(1)の周りにリング状に配置されて
いる。個々のカーボンヒーター(2)は、それぞれケース
(6)並びに断熱材(4)に設けられた測定孔(9)により放
射されるヒーターの熱を温度計(7)で測定できるように
なっていて、この測定値は図示は省略したが信号として
制御系に送られ、該制御系はすべてのヒーターの温度を
同一とするように制御することができる。これにより、
光ファイバ母材の円周方向での温度が均一となり、延伸
された光ファイバ(10) の断面は非常に真円に近いもの
となる。温度系(7)として具体的には放射温度計を使用
し、断熱材(4)としては、例えばカーボンフェルト等を
使用する。またケース(6)は例えばステンレス鋼等で形
成され水冷できる構造となっている。Operation and Examples A heating furnace for drawing an optical fiber preform according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of the present invention. (1) shows an optical fiber preform, (2) shows a carbon heater, and (4) shows a heat insulating material. In the example of FIG. 1, four carbon heaters (2) are connected to a power source (5), respectively, and are arranged in a ring shape around the optical fiber preform (1). Each carbon heater (2) can measure the heat of the heater radiated by the measurement hole (9) provided in the case (6) and the heat insulating material (4) with the thermometer (7). Although not shown, this measured value is sent to the control system as a signal, and the control system can control the temperature of all the heaters to be the same. This allows
The temperature of the optical fiber preform becomes uniform in the circumferential direction, and the cross section of the stretched optical fiber (10) becomes very close to a perfect circle. Specifically, a radiation thermometer is used as the temperature system (7) and, for example, carbon felt or the like is used as the heat insulating material (4). The case (6) is made of, for example, stainless steel or the like and has a structure that can be water-cooled.
【0006】また、本発明者らは延伸された光ファイバ
の位置を一定にすることによっても光ファイバ母材の円
周方向での温度の均一性が図れることをも見いだした。
即ち、図2に示す如く、円周方向での温度の不均一性が
あると光ファイバ母材は非対称に伸ばされてしまい、加
熱炉出口での光ファイバの位置が変化する。図2におい
ては向かって右側のカーボンヒーター温度が高いため
に、光ファイバ母材の右側がより溶融し母材は非対称に
延ばされ光ファイバ(10)は向かって左側へ移動してし
まう。この光ファイバ(10)の位置を位置測定器(8)で
測定して、図示されていない制御系を介して光ファイバ
(10)の移動している側のカーボンヒーター温度を上げ
るように、または逆に移動していない側のカーボンヒー
ターの温度を下げるようにカーボンヒーターへの電気供
給量を制限することにより、常に加熱炉の中心位置に光
ファイバ(10)が位置するようにすることによっても均
一な温度分布が得られ、非円率の小さい光ファイバを延
伸することが可能となった。The present inventors have also found that the temperature uniformity in the circumferential direction of the optical fiber preform can be achieved also by keeping the position of the stretched optical fiber constant.
That is, as shown in FIG. 2, if there is temperature nonuniformity in the circumferential direction, the optical fiber preform is stretched asymmetrically, and the position of the optical fiber at the exit of the heating furnace changes. Since the temperature of the carbon heater on the right side in FIG. 2 is high, the right side of the optical fiber preform is more melted, the preform is asymmetrically extended, and the optical fiber (10) moves toward the left side. The position of the optical fiber (10) is measured by a position measuring device (8) to raise the temperature of the carbon heater on the moving side of the optical fiber (10) via a control system (not shown), or Conversely, by limiting the amount of electricity supplied to the carbon heater so as to lower the temperature of the carbon heater on the non-moving side, it is possible to keep the optical fiber (10) always at the center of the heating furnace. A uniform temperature distribution was obtained, and it became possible to draw an optical fiber with a small non-circularity.
【0007】〔実施例〕本発明により図1の構成の加熱
炉を用いて、光ファイバ外周のヒーターの円周方向の温
度が2100±2℃になるよう制御しながら、外径24
mmφの光ファイバ母材を延伸し、外径125μmの光
ファイバに紡糸した。このときの温度計は放射温度計を
用いた。得られた光ファイバの非円率〔外径差/外径×
100(%)〕を測定したところ、0〜0.2%と小さ
い光ファイバであった。[Examples] [0007] According to the present invention, an outer diameter of 24 is controlled by controlling the temperature of the heater on the outer circumference of the optical fiber in the circumferential direction to be 2100 ± 2 ° C by using the heating furnace having the configuration of Fig. 1.
The mmφ optical fiber preform was drawn and spun into an optical fiber having an outer diameter of 125 μm. A radiation thermometer was used as the thermometer at this time. Non-circularity of the obtained optical fiber [outer diameter difference / outer diameter x
100 (%)], the optical fiber was as small as 0 to 0.2%.
【0008】〔比較例〕図3に示す従来構成の加熱炉に
より、光ファイバ母材と設定加熱温度は実施例1と同様
にして外径125μmの光ファイバを紡糸した。得られ
た光ファイバの非円率は0.3〜0.6%と、実施例の
本発明品より高かった。[Comparative Example] An optical fiber having a 125 μm outer diameter was spun by the conventional heating furnace shown in FIG. The non-circularity of the obtained optical fiber was 0.3 to 0.6%, which was higher than that of the inventive product of the example.
【0009】[0009]
【発明の効果】本発明の光ファイバ母材延伸用加熱炉
は、複数個のカーボンヒーターを光ファイバ母材外周に
リング状に配置し、各々のヒーターの温度を同一になる
よう制御しながら延伸、紡糸することが可能であるた
め、母材円周での温度分布が均一にでき、非円率の小さ
い光ファイバを製造することが可能であり、このように
真円に近い光ファイバは接続等が容易であり、非常に有
効なものである。In the heating furnace for drawing an optical fiber preform of the present invention, a plurality of carbon heaters are arranged in a ring shape on the outer periphery of the optical fiber preform, and the drawing is performed while controlling the temperature of each heater to be the same. Since the fiber can be spun, the temperature distribution on the circumference of the base material can be made uniform, and it is possible to manufacture an optical fiber with a small non-circularity. Etc. are easy and very effective.
【0010】[0010]
【図1】は本発明の光ファイバ母材延伸用加熱炉の一実
施態様を説明する母材の軸方向に垂直方向の概略断面図
である。FIG. 1 is a schematic sectional view of a heating furnace for drawing an optical fiber preform according to an embodiment of the present invention in a direction perpendicular to an axial direction of the preform.
【図2】は本発明の別の実施態様である、位置測定器に
より光ファイバ位置を制御して母材外周を均一に加熱す
る例を示す母材軸方向の概略断面図である。FIG. 2 is a schematic cross-sectional view in the axial direction of the preform showing another example of the present invention, in which the position of the optical fiber is controlled by a position measuring device to uniformly heat the outer circumference of the preform.
【図3】は従来の加熱炉を説明する概略図である。FIG. 3 is a schematic diagram illustrating a conventional heating furnace.
1 光ファイバ母材、 2 カーボンヒーター、3 電
極、 4 断熱材、5 電源、 6 ケース、 7 温
度計、 8 位置測定器、 9 測定孔、10 光ファ
イバ。1 optical fiber base material, 2 carbon heater, 3 electrodes, 4 heat insulating material, 5 power source, 6 case, 7 thermometer, 8 position measuring instrument, 9 measuring hole, 10 optical fiber.
Claims (3)
加熱炉において、独立した複数個のヒーターを光ファイ
バ母材の外周にリング状に配置してなることを特徴とす
る光ファイバ母材延伸用加熱炉加熱炉。1. A heating furnace for heating, melting and stretching an optical fiber preform, wherein a plurality of independent heaters are arranged in a ring shape on the outer periphery of the optical fiber preform. Drawing furnace heating furnace.
を測定する手段及び該測定手段で得られた測定値により
上記の個々のヒーターが円周方向で同一温度となるよう
制御する手段を有してなる請求項1記載の光ファイバ母
材延伸用加熱炉。2. A means for measuring the temperature of the plurality of independent heaters, and a means for controlling the individual heaters to have the same temperature in the circumferential direction based on the measurement values obtained by the measuring means. A heating furnace for drawing an optical fiber preform according to claim 1.
伸された光ファイバの位置の測定手段及び該測定手段で
得られた測定値により延伸された光ファイバ位置を一定
になるように上記の個々のヒーターの温度を制御する手
段を有してなる請求項1又は請求項2記載の光ファイバ
母材延伸用加熱炉。3. A means for measuring the position of the optical fiber stretched by heating, melting and stretching, and the above-mentioned individual so that the stretched optical fiber position becomes constant according to the measurement value obtained by the measuring means. The heating furnace for drawing an optical fiber preform according to claim 1 or 2, further comprising means for controlling the temperature of the heater.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5022693A JPH06235828A (en) | 1993-02-10 | 1993-02-10 | Heating furnace for drawing optical fiber preform |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5022693A JPH06235828A (en) | 1993-02-10 | 1993-02-10 | Heating furnace for drawing optical fiber preform |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH06235828A true JPH06235828A (en) | 1994-08-23 |
Family
ID=12089958
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5022693A Pending JPH06235828A (en) | 1993-02-10 | 1993-02-10 | Heating furnace for drawing optical fiber preform |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH06235828A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0752393A1 (en) * | 1995-07-05 | 1997-01-08 | Sumitomo Electric Industries, Ltd | Furnace for drawing an optical fiber from a preform |
KR100298045B1 (en) * | 1998-11-23 | 2001-09-06 | 권문구 | Radiation Loss Reduction Device for Optical Fiber Manufacturing Using Cylindrical and Spherical Mirrors |
JP2002211942A (en) * | 2001-01-10 | 2002-07-31 | Shin Etsu Chem Co Ltd | Drawing machine for glass perform |
US6941774B2 (en) * | 2001-08-16 | 2005-09-13 | Kobe Steel, Ltd. | Optical fiber preform-heating furnace |
JP2006056755A (en) * | 2004-08-23 | 2006-03-02 | Furukawa Electric Co Ltd:The | Method for producing optical fiber preform |
-
1993
- 1993-02-10 JP JP5022693A patent/JPH06235828A/en active Pending
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0752393A1 (en) * | 1995-07-05 | 1997-01-08 | Sumitomo Electric Industries, Ltd | Furnace for drawing an optical fiber from a preform |
AU718301B2 (en) * | 1995-07-05 | 2000-04-13 | Sumitomo Electric Industries, Ltd. | Optical fiber drawing furnace |
US6546760B1 (en) | 1995-07-05 | 2003-04-15 | Sumitomo Electric Industries, Ltd. | Optical fiber drawing furnace with a zig zag heating element |
KR100298045B1 (en) * | 1998-11-23 | 2001-09-06 | 권문구 | Radiation Loss Reduction Device for Optical Fiber Manufacturing Using Cylindrical and Spherical Mirrors |
JP2002211942A (en) * | 2001-01-10 | 2002-07-31 | Shin Etsu Chem Co Ltd | Drawing machine for glass perform |
US6941774B2 (en) * | 2001-08-16 | 2005-09-13 | Kobe Steel, Ltd. | Optical fiber preform-heating furnace |
JP2006056755A (en) * | 2004-08-23 | 2006-03-02 | Furukawa Electric Co Ltd:The | Method for producing optical fiber preform |
JP4609839B2 (en) * | 2004-08-23 | 2011-01-12 | 古河電気工業株式会社 | Optical fiber preform manufacturing method |
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