JP2005225733A - Furnace and method for drawing optical fiber - Google Patents
Furnace and method for drawing optical fiber Download PDFInfo
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- JP2005225733A JP2005225733A JP2004037506A JP2004037506A JP2005225733A JP 2005225733 A JP2005225733 A JP 2005225733A JP 2004037506 A JP2004037506 A JP 2004037506A JP 2004037506 A JP2004037506 A JP 2004037506A JP 2005225733 A JP2005225733 A JP 2005225733A
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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
- C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
- C03B37/02736—Means for supporting, rotating or feeding the tubes, rods, fibres or filaments to be drawn, e.g. fibre draw towers, preform alignment, butt-joining preforms or dummy parts during feeding
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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
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- 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
- C03B2205/80—Means for sealing the preform entry or upper end of the furnace
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- 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
- C03B2205/90—Manipulating the gas flow through the furnace other than by use of upper or lower seals, e.g. by modification of the core tube shape or by using baffles
- C03B2205/92—Manipulating the gas flow through the furnace other than by use of upper or lower seals, e.g. by modification of the core tube shape or by using baffles using means for gradually reducing the cross-section towards the outlet or around the preform draw end, e.g. tapered
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- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
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- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
本発明は、光ファイバ線引炉及び光ファイバ線引き方法に関する。 The present invention relates to an optical fiber drawing furnace and an optical fiber drawing method.
光ファイバは、線引炉内で石英を主成分とした光ファイバ母材を加熱溶融して、線引きすることにより製造される。線引炉内部には、内部部品の劣化・酸化を防ぐために不活性ガスを常時流入させているが、線引炉内での不活性ガスの気流に乱れが生じると、光ファイバの外径の変動が発生しやすくなる。この対策として、不活性ガスの流動を安定化するための種々の技術が開示されている(例えば、特許文献1及び特許文献2参照)。 The optical fiber is manufactured by heating and melting an optical fiber preform mainly composed of quartz in a drawing furnace and drawing the optical fiber preform. An inert gas is always allowed to flow into the drawing furnace to prevent deterioration and oxidation of internal parts. However, if the inert gas flow in the drawing furnace is disturbed, the outer diameter of the optical fiber is reduced. Fluctuation is likely to occur. As countermeasures, various techniques for stabilizing the flow of an inert gas have been disclosed (see, for example, Patent Document 1 and Patent Document 2).
従来の光ファイバ線引炉の一例を図5に示す(特許文献1。)。図5に示す光ファイバ線引炉100は、炉芯部101と煙突部102とからなる。炉芯部101は、カーボン等からなる炉芯管103の周囲にヒータ104を設けた構造であり、煙突部102は、炉芯管103と同径の内筒管107を有している。
内筒管107の上部壁面には不活性ガス噴出口111が形成され、不活性ガスが光ファイバ線引炉100内に連続的に流入されるようになっている。ダミー棒109に光ファイバ母材110が支持されており、ダミー棒109の途中には、円盤状の仕切板120が係止され、炉内の光ファイバ母材110より上方の空間を上下に画成している。
An example of a conventional optical fiber drawing furnace is shown in FIG. 5 (Patent Document 1). An optical fiber drawing furnace 100 shown in FIG. 5 includes a furnace core 101 and a chimney 102. The furnace core portion 101 has a structure in which a heater 104 is provided around a furnace core tube 103 made of carbon or the like, and the chimney portion 102 has an inner tube 107 having the same diameter as the furnace core tube 103.
An inert gas outlet 111 is formed on the upper wall surface of the inner tube 107 so that the inert gas can continuously flow into the optical fiber drawing furnace 100. An optical fiber preform 110 is supported on the dummy rod 109, and a disk-shaped partition plate 120 is locked in the middle of the dummy rod 109, so that a space above the optical fiber preform 110 in the furnace is vertically divided. It is made.
また、光ファイバ線引炉の別の従来例を図6に示す(特許文献2)。図6に示す光ファイバ線引炉200は、炉心管210の上部に内筒管205と外筒管206とが連結されており、内筒管205の内面に、外部から不活性ガスを流入するガス吹き込み孔208を有している。ダミー棒202には、複数の仕切板204を貫挿して連結部203上に配置している。光ファイバ201aの線引きが進行して、ダミー棒202と共に光ファイバ母材201が降下するに従い、複数組の仕切板204は、上部の仕切板から順次内筒管205の内壁面に1組ずつ係止される。 FIG. 6 shows another conventional example of an optical fiber drawing furnace (Patent Document 2). In an optical fiber drawing furnace 200 shown in FIG. 6, an inner tube 205 and an outer tube 206 are connected to an upper portion of a core tube 210, and an inert gas flows into the inner surface of the inner tube 205 from the outside. A gas blowing hole 208 is provided. A plurality of partition plates 204 are inserted into the dummy bar 202 and disposed on the connecting portion 203. As the drawing of the optical fiber 201a progresses and the optical fiber preform 201 descends together with the dummy rod 202, the plurality of sets of partition plates 204 are sequentially engaged with the inner wall surface of the inner tube 205 one by one from the upper partition plate. Stopped.
特許文献1の光ファイバ線引炉の場合、不活性ガス噴出口から入った不活性ガスは、仕切板より上方の空間内に一旦入り、図5の矢印で示すように、仕切板の通気孔又は仕切板と内筒管との隙間から下方空間に流入する。しかし、仕切板の上方空間が大きいため、不活性ガスの対流が起こり、不活性ガスの気流の乱れが発生しやすくなる。この仕切板の上方空間での気流の乱れが下方空間に伝わり、光ファイバ母材の周囲の不活性ガスの流動を安定化させることが困難となる。 In the case of the optical fiber drawing furnace of Patent Document 1, the inert gas that has entered from the inert gas outlet once enters the space above the partition plate, and as shown by the arrows in FIG. Or, it flows into the lower space through the gap between the partition plate and the inner tube. However, since the space above the partition plate is large, convection of the inert gas occurs, and disturbance of the air flow of the inert gas is likely to occur. The turbulence of the airflow in the upper space of the partition plate is transmitted to the lower space, and it becomes difficult to stabilize the flow of the inert gas around the optical fiber preform.
特許文献2の光ファイバ線引炉は、内筒管内の空間を幾つもの上下部分に仕切ることで、仕切板によって仕切られた各空間の大きさを小さくし、不活性ガスの気流をより安定化させたものである。しかしながら、図6の矢印で示すように、複数の仕切板を備えているために加熱ヒータの直ぐ上方に不活性ガス流入口が設置せざるを得ず、このため、常温の不活性ガスが光ファイバ母材下端の加熱溶融部分に流入することになり、光ファイバ母材周囲の温度分布が乱れて光ファイバの外径に変動が生じてしまう。 The optical fiber drawing furnace of Patent Document 2 divides the space in the inner tube into a number of upper and lower parts, thereby reducing the size of each space partitioned by the partition plate and further stabilizing the air flow of the inert gas. It has been made. However, as shown by the arrows in FIG. 6, since a plurality of partition plates are provided, an inert gas inflow port must be installed immediately above the heater, so that the inert gas at room temperature is not light. It flows into the heating and melting part at the lower end of the fiber preform, and the temperature distribution around the optical fiber preform is disturbed, resulting in fluctuations in the outer diameter of the optical fiber.
本発明は以上の問題点に鑑みなされたものであり、その目的は、炉内の温度分布が均一で気流の乱れが発生しない光ファイバ線引炉を提供することである。
また、本発明の別の目的は、外径の均一な光ファイバを製造できる光ファイバ線引き方法を提供することである。
The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical fiber drawing furnace in which the temperature distribution in the furnace is uniform and the turbulence of airflow does not occur.
Another object of the present invention is to provide an optical fiber drawing method capable of producing an optical fiber having a uniform outer diameter.
本発明に係る光ファイバ線引炉は、煙突部と炉芯部との内部に形成された線引室を有し、前記線引室の上方にガス流入口を備え、前記線引室内でダミー棒に支えられた光ファイバ母材を加熱溶融して光ファイバを線引きする光ファイバ線引炉であって、
前記煙突部内の前記線引室を上下に仕切るための複数の仕切板と、前記仕切板が係止される複数の係止部とを備え、前記仕切板は、前記ダミー棒を貫通させる貫通孔と気体が流通する通気孔とを有し、前記複数の仕切板同士は、気体の流通が可能に間隔が保持されていることを特徴としている。
An optical fiber drawing furnace according to the present invention has a drawing chamber formed inside a chimney portion and a furnace core portion, and has a gas inflow port above the drawing chamber, and a dummy in the drawing chamber. An optical fiber drawing furnace for drawing an optical fiber by heating and melting an optical fiber preform supported by a rod,
A plurality of partition plates for vertically partitioning the drawing chamber in the chimney, and a plurality of locking portions for locking the partition plates, the partition plate being a through-hole through which the dummy bar passes And a vent hole through which gas flows, and the plurality of partition plates are characterized in that the gap is maintained so that gas can flow.
上記のように構成された光ファイバ線引炉は、気体を上方から流入させると共に、通気孔を有する仕切板が炉内を複数の空間に仕切ることにより、気流の乱れを緩衝し、光ファイバ母材周囲の気体の流動を安定化することができる。また、上方から流入した気体は、複数の空間を通過することにより、徐々に線引室内の温度に暖められて、光ファイバ母材の加熱溶融部分に到達するので、光ファイバ母材の加熱溶融部分に温度差の大きい気体が流入することがない。
また、上記のように構成された光ファイバ線引炉は、常に気体の流通が確保されるように複数の仕切板同士の間隔が保持されているので、通気孔が互いの仕切板によって塞がれることがなく、線引き開始直後に複数の仕切板が重なって待機している時でも、上方から流入した気体を下方へ流通させることができる。
The optical fiber drawing furnace configured as described above allows gas to flow from above, and a partition plate having a vent hole partitions the interior of the furnace into a plurality of spaces, thereby buffering the turbulence of the air flow and The flow of gas around the material can be stabilized. In addition, the gas flowing in from above passes through a plurality of spaces, and is gradually warmed to the temperature in the drawing chamber and reaches the heating and melting portion of the optical fiber preform, so that the optical fiber preform is heated and melted. Gas with a large temperature difference does not flow into the part.
Further, the optical fiber drawing furnace configured as described above maintains the interval between the plurality of partition plates so that the gas flow is always ensured, so that the air holes are closed by the partition plates. Even when a plurality of partition plates overlap and stand by immediately after the start of drawing, the gas flowing in from above can be circulated downward.
前記仕切板は第一部材と第二部材とから構成され、前記第一部材は、前記貫通孔を有する貫通孔領域と前記通気孔を有する通気孔領域とを有し、前記第二部材の貫通孔の直径は、前記第一部材の貫通孔の直径より小さく、前記第二部材の外径は、前記第一部材の貫通孔の直径より大きく、かつ前記通気孔領域の内直径より小さいことが好ましい。 The partition plate includes a first member and a second member, and the first member has a through-hole region having the through-hole and a vent-hole region having the vent hole, and is penetrated by the second member. The diameter of the hole is smaller than the diameter of the through hole of the first member, and the outer diameter of the second member is larger than the diameter of the through hole of the first member and smaller than the inner diameter of the vent hole region. preferable.
また、本発明に係る光ファイバ線引き方法は、上記光ファイバ線引炉を用いる光ファイバ線引き方法であって、前記光ファイバ母材の降下に従って、前記複数の仕切板を最上部の仕切板から順次一つずつ係止部に係止することを特徴としている。 Further, an optical fiber drawing method according to the present invention is an optical fiber drawing method using the optical fiber drawing furnace, wherein the plurality of partition plates are sequentially arranged from the uppermost partition plate according to the descending of the optical fiber preform. It is characterized by being locked to the locking portion one by one.
このような光ファイバ線引き方法によれば、温度分布が均一で炉内の気流の乱れのない状態で光ファイバを線引きできるので、外径が均一な光ファイバを製造できる。 According to such an optical fiber drawing method, the optical fiber can be drawn in a state where the temperature distribution is uniform and the air flow in the furnace is not disturbed, so that an optical fiber having a uniform outer diameter can be manufactured.
本発明の光ファイバ線引炉は、不活性ガスを線引室の上方から流入させると共に、通気孔を有する仕切板で炉内の上方を複数の空間に仕切ることにより、炉内の気流を安定化させ、かつ温度分布を均一にすることができる。したがって、外径が均一な光ファイバを製造することができるものである。また、本発明の光ファイバ線引き方法は、本発明の光ファイバ線引炉を用いることにより、外径が均一な光ファイバを製造できる。 The optical fiber drawing furnace of the present invention stabilizes the airflow in the furnace by allowing an inert gas to flow from above the drawing chamber and partitioning the inside of the furnace into a plurality of spaces with a partition plate having a vent hole. And uniform temperature distribution. Therefore, an optical fiber having a uniform outer diameter can be manufactured. Moreover, the optical fiber drawing method of the present invention can produce an optical fiber having a uniform outer diameter by using the optical fiber drawing furnace of the present invention.
以下、本発明に係る光ファイバ線引炉の実施形態を、図面に基づいて説明する。
図1は、本発明の実施形態に係る光ファイバ線引炉50の概略を示す縦断面図である。図1に示す光ファイバ線引炉50は、例えばカーボン製の炉芯部1の上方に、煙突部2が設けられた構造である。炉芯部1の外周にはヒータ4を備えており、さらにヒータ4の周囲は断熱材6で覆われている。炉芯部1の下端には、線引きされた光ファイバ12が引き出される下端開口1bが設けられている。煙突部2の上端は、上蓋20で閉塞されており、上蓋20はダミー棒3を貫通する開口部21を有する。開口部21は、その大きさが拡縮可能に構成されている。
炉芯部1と煙突部2とは連続して一つの空間を形成しており、この炉芯部1と煙突部2とで形成された空間が線引室8となっている。煙突部2の上部壁面にはガス流入口9が設けられ、ヘリウムガスや窒素ガス等の不活性ガスを線引室8の上方から内部に連続的に供給している。
Embodiments of an optical fiber drawing furnace according to the present invention will be described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an outline of an optical fiber drawing furnace 50 according to an embodiment of the present invention. An optical fiber drawing furnace 50 shown in FIG. 1 has a structure in which a chimney 2 is provided above a furnace core 1 made of carbon, for example. A heater 4 is provided on the outer periphery of the furnace core portion 1, and the periphery of the heater 4 is covered with a heat insulating material 6. At the lower end of the furnace core portion 1, a lower end opening 1 b from which the drawn optical fiber 12 is drawn is provided. The upper end of the chimney 2 is closed by the upper lid 20, and the upper lid 20 has an opening 21 that penetrates the dummy bar 3. The opening 21 is configured such that its size can be expanded and contracted.
The furnace core part 1 and the chimney part 2 continuously form one space, and the space formed by the furnace core part 1 and the chimney part 2 is a drawing chamber 8. A gas inlet 9 is provided on the upper wall surface of the chimney 2, and an inert gas such as helium gas or nitrogen gas is continuously supplied from above the drawing chamber 8.
また、図1に示す光ファイバ線引炉50は、線引室8に光ファイバ母材10を支持するダミー棒3が配置され、光ファイバ母材10の上端部とダミー棒3の下端部とは連結部11により連結される。
連結部11より上方には、複数の仕切板7がダミー棒3に積層してはめ込まれており、仕切板同士の間には円筒状のスペーサ5が配置され、仕切板7同士の間隔を保持している。仕切板7は、それぞれ円環状の第一部材7aと円環状の第二部材7bとから構成されている。第一部材7aの外径は、上方から下方に向かって、徐々に小さくなっている。
Further, in the optical fiber drawing furnace 50 shown in FIG. 1, the dummy rod 3 that supports the optical fiber preform 10 is disposed in the drawing chamber 8, and the upper end portion of the optical fiber preform 10 and the lower end portion of the dummy rod 3 are arranged. Are connected by a connecting portion 11.
Above the connecting portion 11, a plurality of partition plates 7 are stacked and fitted on the dummy bar 3, and a cylindrical spacer 5 is disposed between the partition plates to maintain a space between the partition plates 7. doing. The partition plate 7 includes an annular first member 7a and an annular second member 7b. The outer diameter of the first member 7a is gradually reduced from the upper side to the lower side.
さらに、煙突部2の内部壁面には、仕切板7の第一部材7aの外周縁を係止する係止部14が設けられている。係止部14は、煙突部2の下方に向かって階段状に形成されており、係止部14ごとに煙突部2の内径が段階的に小さくなっている。 Furthermore, a locking portion 14 that locks the outer peripheral edge of the first member 7 a of the partition plate 7 is provided on the inner wall surface of the chimney portion 2. The locking portion 14 is formed in a stepped shape toward the lower side of the chimney portion 2, and the inner diameter of the chimney portion 2 is gradually reduced for each locking portion 14.
本実施形態に係る仕切板7について、図2を参照して、より詳細に説明する。図2(A)及び(B)は、仕切板7の第一部材7a及び第二部材7bの上面を示す平面図である。図2(A)に示すように、第一部材7aは、第一部材7aと同心円状の貫通孔領域77と通気孔領域78とからなる。貫通孔領域77は、ダミー棒3を挿通する貫通孔71が中心部に形成されている領域であり、通気孔領域78は、第一部材7aの外周に沿って複数の通気孔72が形成されている領域である。また、図2(B)に示すように、第二部材7bは中心部にダミー棒3を挿通する貫通孔75が設けられている。
ここで、第一部材7aの貫通孔71の直径をD1とし、通気孔72’から最遠の通気孔72”までの距離を通気孔領域の内直径D3と定義する。また、第二部材7bの貫通孔75の直径をd1、第二部材7bの外径をd2とする。
The partition plate 7 according to the present embodiment will be described in more detail with reference to FIG. 2A and 2B are plan views showing the top surfaces of the first member 7a and the second member 7b of the partition plate 7. FIG. As shown in FIG. 2A, the first member 7a includes a through-hole region 77 and a vent hole region 78 that are concentric with the first member 7a. The through-hole region 77 is a region where a through-hole 71 through which the dummy rod 3 is inserted is formed at the center, and the vent hole region 78 is formed with a plurality of vent holes 72 along the outer periphery of the first member 7a. It is an area. As shown in FIG. 2B, the second member 7b is provided with a through-hole 75 through which the dummy bar 3 is inserted at the center.
Here, the diameter of the through hole 71 of the first member 7a is defined as D1, and the distance from the vent hole 72 ′ to the farthest vent hole 72 ″ is defined as the inner diameter D3 of the vent hole region. The second member 7b. The diameter of the through hole 75 is d1, and the outer diameter of the second member 7b is d2.
第二部材7bの貫通孔75の直径d1は、ダミー棒3の外径とほぼ同径である。ここで、「第二部材7bの貫通孔75の直径d1がダミー棒3の外径とほぼ同径である」とは、ダミー棒3の外径よりも僅かに大きく、ダミー棒3が貫通孔75を通過可能な程度の直径であることをいう。
また、第二部材7bの貫通孔75の直径d1は、第一部材7aの貫通孔71の直径D1より小さくなるように形成されている。第二部材7bの外径d2は、第一部材7aの貫通孔71の直径D1より大きく、通気孔領域における内直径D3より小さくなるように形成されており、通気孔領域78の通気孔72を塞がないようになっている。以上の関係をまとめると、d1<D1<d2<D3となる。
The diameter d1 of the through hole 75 of the second member 7b is substantially the same as the outer diameter of the dummy bar 3. Here, “the diameter d1 of the through hole 75 of the second member 7b is substantially the same as the outer diameter of the dummy bar 3” means that the dummy bar 3 is slightly larger than the outer diameter of the dummy bar 3. The diameter is such that it can pass through 75.
The diameter d1 of the through hole 75 of the second member 7b is formed to be smaller than the diameter D1 of the through hole 71 of the first member 7a. The outer diameter d2 of the second member 7b is formed to be larger than the diameter D1 of the through hole 71 of the first member 7a and smaller than the inner diameter D3 in the vent hole region. There is no blockage. To summarize the above relationship, d1 <D1 <d2 <D3.
上記のように、仕切板7が第一部材7aと第二部材7bとから構成されていると、ダミー棒3(図1)が線引室8の長手方向に垂直な方向に揺動した時に、第一部材7aが係止部14に固定された状態で、第二部材7bがダミー棒3と共に第一部材7a上を滑り動くことができる。従って、このように構成された光ファイバ線引炉50は、ダミー棒3の揺動に追従して第二部材7bがスライドできるため、仕切板に割れ等が発生することがなく、好ましい。 As described above, when the partition plate 7 is composed of the first member 7a and the second member 7b, when the dummy bar 3 (FIG. 1) swings in a direction perpendicular to the longitudinal direction of the drawing chamber 8. In a state where the first member 7 a is fixed to the locking portion 14, the second member 7 b can slide on the first member 7 a together with the dummy bar 3. Therefore, the optical fiber drawing furnace 50 configured as described above is preferable because the second member 7b can slide following the swinging of the dummy rod 3, so that the partition plate is not cracked.
なお、隣接した2枚の仕切板7同士の間に配置されたスペーサ5(図1)の内径は、ダミー棒3の外径よりほぼ同径かそれよりも大きく、第一部材7bの貫通孔71の大きさD1よりも小さくなるように形成されている。 The inner diameter of the spacer 5 (FIG. 1) disposed between two adjacent partition plates 7 is substantially the same as or larger than the outer diameter of the dummy bar 3, and the through hole of the first member 7b. It is formed to be smaller than the size D1 of 71.
次に、本実施形態に係る光ファイバ線引炉50を用いて光ファイバを線引きする方法を説明する。図1に示すように、ダミー棒3を複数の仕切板7(第一部材7a及び第二部材7b)及びスペーサ5に挿通させる。連結部11ではダミー棒3の下端に光ファイバ母材10の上端を連結し、ダミー棒3を連結した光ファイバ母材10を線引室8内へ導入し、光ファイバ母材10の下端をヒータ4の位置まで降下させる。そして、煙突部2の上部開口部を上蓋20によって閉塞し、不活性ガスをガス流入口9より線引室8内へ流入させて、線引室8内部が不活性ガスで十分満たされるようにする。ヒータ4を作動させて炉芯部1を加熱し、光ファイバ母材10の下端から光ファイバ12を線引し、下端開口1bから外部へ送出する。 Next, a method for drawing an optical fiber using the optical fiber drawing furnace 50 according to the present embodiment will be described. As shown in FIG. 1, the dummy bar 3 is inserted through a plurality of partition plates 7 (first member 7 a and second member 7 b) and spacer 5. In the connecting portion 11, the upper end of the optical fiber preform 10 is connected to the lower end of the dummy rod 3, the optical fiber preform 10 connected to the dummy rod 3 is introduced into the drawing chamber 8, and the lower end of the optical fiber preform 10 is Lower to the position of the heater 4. And the upper opening part of the chimney part 2 is obstruct | occluded with the upper cover 20, and an inert gas is made to flow in into the drawing chamber 8 from the gas inflow port 9, and the inside of the drawing chamber 8 is fully filled with an inert gas. To do. The heater core 4 is heated by operating the heater 4, the optical fiber 12 is drawn from the lower end of the optical fiber preform 10, and sent to the outside through the lower end opening 1 b.
光ファイバ12の線引き開始直後は、光ファイバ母材10が長大でダミー棒3が線引室8の下方まで移動していないため、ダミー棒3にはめ込まれた複数の仕切板7は係止部14に係止されず、スペーサ5と共に煙突部2の上方で多段に積み重なった状態で待機している。
ここで、複数の仕切板7がスペーサ5と共に多段に積み重なって待機した状態を示す縦断面図を図3に示す。図3に示す複数の仕切板は、第一部材31a〜34aと第二部材31b〜34bとから構成されている。第一部材31a〜34a及び第二部材31b〜34bは、第二部材31bと第一部材31aと第二部材32b、第一部材32aと第二部材33b、第一部材33aと第二部材34b、第一部材34aと第二部材35b、とがそれぞれ一組となって積層している。そして、第二部材32b〜34bの間には、それぞれスペーサ33c〜35cが配置されており、第一部材31a〜34a同士が重なり合わないように間隔が保持されている。なお、最下部の第二部材35bは、ダミー棒3下端の連結部11上に載置され、上記のように多段に積み重ねられた仕切板全体が支持されている。
Immediately after the drawing of the optical fiber 12 is started, the optical fiber preform 10 is long and the dummy bar 3 has not moved below the drawing chamber 8, so that the plurality of partition plates 7 fitted into the dummy bar 3 have locking portions. 14 is not locked and is waiting in a state of being stacked in multiple stages above the chimney 2 together with the spacer 5.
Here, the longitudinal cross-sectional view which shows the state which the several partition plate 7 piled up with the spacer 5 in multiple steps and waited is shown in FIG. The some partition plate shown in FIG. 3 is comprised from the 1st members 31a-34a and the 2nd members 31b-34b. The first members 31a to 34a and the second members 31b to 34b are the second member 31b, the first member 31a and the second member 32b, the first member 32a and the second member 33b, the first member 33a and the second member 34b, The first member 34a and the second member 35b are laminated as a set. Then, spacers 33c to 35c are disposed between the second members 32b to 34b, respectively, and the intervals are maintained so that the first members 31a to 34a do not overlap each other. The lowermost second member 35b is placed on the connecting portion 11 at the lower end of the dummy bar 3, and the entire partition plates stacked in multiple stages as described above are supported.
このように、上記の本実施形態の光ファイバ線引炉50は、複数の仕切板が多段に重なって待機している状態でも、常に不活性ガスの流通が確保されるように、第一部材31a〜34aの間隔がスペーサ33c〜35cによって保持されている。従って、第一部材31a〜34aの通気孔が互いの仕切板によって塞がれることがなく、上方から流入した不活性ガスを下方へ流通させることができる。そのため、線引室8の下方の炉芯部1内も不活性ガス雰囲気とすることができるので、炉芯部1のカーボンの酸化を防止できる。 As described above, the optical fiber drawing furnace 50 according to the present embodiment is configured so that the flow of the inert gas is always ensured even when the plurality of partition plates are waiting in a multi-stage overlapping manner. The intervals 31a to 34a are held by the spacers 33c to 35c. Therefore, the vent holes of the first members 31a to 34a are not blocked by the partition plates, and the inert gas flowing in from above can be circulated downward. Therefore, since the inside of the furnace core part 1 below the drawing chamber 8 can also be made an inert gas atmosphere, the oxidation of carbon in the furnace core part 1 can be prevented.
そして、多段に積み重ねられた第一部材31a〜34aと第二部材31b〜34bは、ダミー棒3の降下に伴い、第一部材31a〜34aが係止部14(図1)に順次係止されていく。図4は、図3に示す仕切板の第一部材31a〜34aが係止部14に係止された状態を示している。なお、図4において、係止部14は図示していない。
図4に示すように、第一部材31a〜34aは、最上部から、第二部材31bと第一部材31aとからなる仕切板31、第二部材32bと第一部材32aとからなる仕切板32、第二部材33bと第一部材33aとからなる仕切板33、及び、第二部材34bと第一部材34aとからなる仕切板34、がこの順序で係止部に係止される。第一部材31a〜34aがこのように係止部に係止されることにより、線引室8(図1)の上方空間を複数の空間に仕切ることができる。スペーサ33c及び34cは、それぞれ第二部材33及び34上に残り、連結部11上に第二部材35bとスペーサ35cが残ることになる。
The first members 31a to 34a and the second members 31b to 34b stacked in multiple stages are sequentially locked to the locking portion 14 (FIG. 1) as the dummy bar 3 is lowered. To go. 4 shows a state in which the first members 31a to 34a of the partition plate shown in FIG. In FIG. 4, the locking portion 14 is not shown.
As shown in FIG. 4, the first members 31a to 34a are, from the top, the partition plate 31 composed of the second member 31b and the first member 31a, and the partition plate 32 composed of the second member 32b and the first member 32a. The partition plate 33 composed of the second member 33b and the first member 33a and the partition plate 34 composed of the second member 34b and the first member 34a are locked to the locking portion in this order. By locking the first members 31a to 34a to the locking portions in this manner, the upper space of the drawing chamber 8 (FIG. 1) can be partitioned into a plurality of spaces. The spacers 33c and 34c remain on the second members 33 and 34, respectively, and the second member 35b and the spacer 35c remain on the connecting portion 11.
以上のように、図1に示す本実施形態の光ファイバ線引炉50は、不活性ガスを上方から流入させると共に、通気孔を有する仕切板7で線引室8の上方空間を複数の空間に仕切りながら、光ファイバ12の線引きを行うことができるものである。このような光ファイバ線引炉50によれば、不活性ガス流入時の気流の乱れを複数の仕切板によって緩衝でき、かつ、仕切板7によって仕切られた空間が小さいため空間内での気流の乱れが生じにくい。よって、本実施形態の光ファイバ線引炉50は、光ファイバ母材10、特に光ファイバ母材10の加熱溶融部分周囲の気流の乱れを防止でき、外径が均一な光ファイバを線引きできるものである。 As described above, the optical fiber drawing furnace 50 according to the present embodiment shown in FIG. 1 allows an inert gas to flow from above, and the partition plate 7 having a vent hole forms a plurality of spaces above the drawing chamber 8. The optical fiber 12 can be drawn while being partitioned. According to such an optical fiber drawing furnace 50, the turbulence of the air flow during the inflow of the inert gas can be buffered by the plurality of partition plates, and the space partitioned by the partition plates 7 is small, so the air flow in the space is reduced. Disturbance is unlikely to occur. Therefore, the optical fiber drawing furnace 50 of the present embodiment can prevent the disturbance of the air current around the optical fiber preform 10, particularly the heated and melted portion of the optical fiber preform 10, and can draw an optical fiber having a uniform outer diameter. It is.
また、線引室8の上方から流入した不活性ガスは、図1に示す矢印のように、仕切板7によって仕切られた幾つもの空間を通過することにより、徐々に線引室8内の温度に暖められ、下方に静かに移動していく。よって、光ファイバ母材10の加熱溶融部分に温度差の大きい気体が流入することがなく、急激な温度変化による外径変動を防止することができる。 Moreover, the inert gas which flowed in from the upper part of the drawing chamber 8 passes through several spaces partitioned by the partition plate 7 as shown by the arrows in FIG. It will be warmed up and move gently downward. Therefore, a gas having a large temperature difference does not flow into the heated and melted portion of the optical fiber preform 10, and fluctuations in the outer diameter due to a sudden temperature change can be prevented.
以上の実施形態においては、複数の仕切板同士は、スペーサによってその間隔が保持されている形態を示したが、本発明に係る光ファイバ線引炉50は、仕切板の間隔が保持されるように構成されていればスペーサを用いなくともよい。例えば、スペーサ5の替わりに第二部材の厚みを厚くすることによって、第一部材同士の間隔を確保するようにしてもよい。
また、第一部材及び第二部材は、図3に示す順序で積み上げているが、待機状態でも仕切板の間隔が保持され、かつ線引室内の上方空間を仕切ることができれば、必ずしも図3に示す順序で積み上げ方でなくともよい。
In the above embodiment, although the space | interval of several partition plates showed the form hold | maintained with the spacer, the optical fiber drawing furnace 50 which concerns on this invention seems to maintain the space | interval of a partition plate. As long as it is configured as described above, the spacer need not be used. For example, the interval between the first members may be secured by increasing the thickness of the second member instead of the spacer 5.
Moreover, although the 1st member and the 2nd member are piled up in the order shown in FIG. 3, if the space | interval of a partition plate is hold | maintained also in a standby state and the upper space in a drawing room can be partitioned, it is not necessarily in FIG. It does not have to be stacked in the order shown.
仕切板を構成する第一部材及び第二部材の材質は、耐熱性を有するものであれば特に限定されず、石英、カーボン、炭化珪素(SiC)等を用いることができる。仕切板の枚数も特に限定されるものではなく、線引炉の規模等により適宜変更することができる。 The material of the first member and the second member constituting the partition plate is not particularly limited as long as it has heat resistance, and quartz, carbon, silicon carbide (SiC), or the like can be used. The number of partition plates is not particularly limited, and can be appropriately changed depending on the scale of the drawing furnace.
図1に示す光ファイバ線引炉50を使用して、外径125μmの光ファイバを線引きしたところ、線形変動は±0.1μmの範囲内であった。一方、比較例として、図6に示す従来の光ファイバ線引炉200を使用して外径125μmの光ファイバを線引きした。その結果、0.3〜0.5μmの線形変動が生じた。 When an optical fiber having an outer diameter of 125 μm was drawn using the optical fiber drawing furnace 50 shown in FIG. 1, the linear variation was within a range of ± 0.1 μm. On the other hand, as a comparative example, an optical fiber having an outer diameter of 125 μm was drawn using a conventional optical fiber drawing furnace 200 shown in FIG. As a result, a linear variation of 0.3 to 0.5 μm occurred.
1 炉芯部
2 煙突部
3 ダミー棒
7 仕切板
7a 第一部材
7b 第二部材
8 線引室
9 ガス流入口
10 光ファイバ母材
71 貫通孔
72,72’,72” 通気孔
77 貫通孔領域
78 通気孔領域
d1 第二部材の貫通孔の直径
d2 第二部材の外径
D1 第一部材の貫通孔の直径
D3 内直径
DESCRIPTION OF SYMBOLS 1 Furnace part 2 Chimney part 3 Dummy rod 7 Partition plate 7a First member 7b Second member 8 Drawing chamber 9 Gas inlet 10 Optical fiber preform 71 Through-hole 72, 72 ', 72 "Vent hole 77 Through-hole area 78 Vent hole area d1 Diameter d2 of through hole of second member Outer diameter D1 of second member Diameter D3 of through hole of first member Inner diameter
Claims (3)
前記煙突部内の前記線引室を上下に仕切るための複数の仕切板と、前記仕切板が係止される複数の係止部とを備え、前記仕切板は、前記ダミー棒を貫通させる貫通孔と気体が流通する通気孔とを有し、前記複数の仕切板同士は、気体の流通が可能に間隔が保持されていることを特徴とする光ファイバ線引炉。 It has a drawing chamber formed inside the chimney and the furnace core, has a gas inlet above the drawing chamber, and heats the optical fiber preform supported by a dummy rod in the drawing chamber An optical fiber drawing furnace for melting and drawing an optical fiber,
A plurality of partition plates for vertically partitioning the drawing chamber in the chimney, and a plurality of locking portions for locking the partition plates, the partition plate being a through-hole through which the dummy bar passes And an air hole through which the gas flows, and the plurality of partition plates are spaced apart so that the gas can flow.
前記第二部材の貫通孔の直径は、前記第一部材の貫通孔の直径より小さく、前記第二部材の外径は、前記第一部材の貫通孔の直径より大きく、かつ前記通気孔領域の内直径より小さいことを特徴とする請求項1に記載の光ファイバ線引炉。 The partition plate includes a first member and a second member, and the first member has a through-hole region having the through-hole and a vent-hole region having the vent.
The diameter of the through hole of the second member is smaller than the diameter of the through hole of the first member, the outer diameter of the second member is larger than the diameter of the through hole of the first member, and 2. The optical fiber drawing furnace according to claim 1, wherein the optical fiber drawing furnace is smaller than the inner diameter.
The optical fiber drawing method using the optical fiber drawing furnace according to claim 1 or 2, wherein the plurality of partition plates are sequentially locked one by one from the uppermost partition plate according to the descending of the optical fiber preform. An optical fiber drawing method characterized in that the optical fiber drawing method is characterized in that the optical fiber drawing method is performed.
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8631669B2 (en) | 2010-04-30 | 2014-01-21 | Fujikura Ltd. | Optical fiber manufacturing apparatus and optical fiber manufacturing method |
CN110577357A (en) * | 2018-06-11 | 2019-12-17 | 住友电气工业株式会社 | Method for drawing optical fiber |
CN113716858A (en) * | 2020-05-25 | 2021-11-30 | 中天科技精密材料有限公司 | Sintering equipment and sintering method |
US11584679B2 (en) * | 2019-12-11 | 2023-02-21 | Corning Incorporated | Apparatuses and methods for processing an optical fiber preform |
-
2004
- 2004-02-13 JP JP2004037506A patent/JP2005225733A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8631669B2 (en) | 2010-04-30 | 2014-01-21 | Fujikura Ltd. | Optical fiber manufacturing apparatus and optical fiber manufacturing method |
CN110577357A (en) * | 2018-06-11 | 2019-12-17 | 住友电气工业株式会社 | Method for drawing optical fiber |
CN110577357B (en) * | 2018-06-11 | 2023-03-03 | 住友电气工业株式会社 | Method for drawing optical fiber |
US11584679B2 (en) * | 2019-12-11 | 2023-02-21 | Corning Incorporated | Apparatuses and methods for processing an optical fiber preform |
CN113716858A (en) * | 2020-05-25 | 2021-11-30 | 中天科技精密材料有限公司 | Sintering equipment and sintering method |
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