JP2013116827A - Method and apparatus for producing glass preform - Google Patents

Method and apparatus for producing glass preform Download PDF

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JP2013116827A
JP2013116827A JP2011263615A JP2011263615A JP2013116827A JP 2013116827 A JP2013116827 A JP 2013116827A JP 2011263615 A JP2011263615 A JP 2011263615A JP 2011263615 A JP2011263615 A JP 2011263615A JP 2013116827 A JP2013116827 A JP 2013116827A
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glass
pipe
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glass pipe
gas supply
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JP5831181B2 (en
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Shinji Hasegawa
慎治 長谷川
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Sumitomo Electric Industries Ltd
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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
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
    • C03B37/01248—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing by collapsing without drawing

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Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing glass preform producible of high quality glass preform smoothly.SOLUTION: The production method for glass preform comprises: connecting a gas supply pipe 27 in which a gas regulated of flow rate by a flow rate controller 39 is fed to a primary side forming an end side of a glass pipe 25 in which a glass rod 23 is inserted; and connecting a gas exhaust pipe 31 to a secondary side forming an other side of the glass pipe 25; and further connecting a bypass pipe 41 to flow surplus of gas supplied to the glass pipe 25 from the gas supply pipe 27 between the gas supply pipe 27 and the gas exhaust pipe 31; in this state, performing integration starting treatment by heating, with a heating oven 37, a part of glass pipe 25 in axial direction to integrate the part of the glass pipe 25 in axial direction with the glass rod 23 in axial direction; and performing a continuous integration treatment by moving the heating oven 37 to integrate the glass pipe 23 and the glass rod 25 across the axial direction to obtain the glass preform. The integration starting treatment and the continuous integration treatment are carried out while the primary side pressure P1 is always held higher than the secondary side pressure P2.

Description

本発明は、ガラスパイプ内にガラスロッドを挿入して、両者を加熱して一体化することで光ファイバ用のガラス母材を製造するガラス母材の製造方法及び製造装置に関する。   The present invention relates to a glass base material manufacturing method and a manufacturing apparatus for manufacturing a glass base material for an optical fiber by inserting a glass rod into a glass pipe and heating and integrating them.

分散補償ファイバや分散シフトファイバといった複雑な屈折率分布を有する光ファイバを製造するのに適したガラス母材の製造方法として、ガラスパイプ内にガラスロッドを挿入した後に両者を加熱して一体化するロッドインコラプス法が知られている。   As a method of manufacturing a glass base material suitable for manufacturing an optical fiber having a complicated refractive index distribution such as a dispersion compensating fiber or a dispersion shifted fiber, a glass rod is inserted into a glass pipe and then both are heated and integrated. The rod-in collapse method is known.

このロッドインコラプス法によるガラス母材の製造方法として、図４に示すように、ガス供給管２７から供給するガスの余剰分を、バイパス管４１を経由してガス排気管３１に逃がし、バイパス管４１に流入するガス流量を測定し、測定されたガス流量とガス供給管から供給するガス流量の差が所定値以下になった後、連続一体化処理を開始する方法が知られている（例えば、特許文献１参照）。   As a method for manufacturing a glass base material by this rod in collapse method, as shown in FIG. 4, excess gas supplied from a gas supply pipe 27 is released to a gas exhaust pipe 31 via a bypass pipe 41, A method is known in which the flow rate of gas flowing into 41 is measured, and the continuous integration process is started after the difference between the measured gas flow rate and the gas flow rate supplied from the gas supply pipe falls below a predetermined value (for example, , See Patent Document 1).

この製造方法によれば、加熱炉に隠れている部位における一体化の進行度合いを、正確に検知でき、その検知結果に応じてガラスパイプ内へのガスの供給を制御することで、ガラスパイプの破損を回避すると共に、下流側の外気の巻き込み等の不都合の発生を防止して、円滑に安定した品質のガラス母材を製造することができる。   According to this manufacturing method, it is possible to accurately detect the progress of integration in the portion hidden in the heating furnace, and by controlling the gas supply into the glass pipe according to the detection result, In addition to avoiding breakage, it is possible to prevent the occurrence of inconvenience such as entrainment of the outside air on the downstream side, and to manufacture a glass base material having a stable quality.

特開２００５−１６２５３１号公報JP 2005-162531 A

ところで、上記の製造方法では、一体化の開始を検知したらガス供給管２７からのガスの供給を停止してガスの供給側を真空吸引装置４７で吸引することにより連続一体化処理を開始する。このため、一体化開始端での一体化が不完全であった（隙間が残った）場合、ガス供給側からガスを吸引することにより、水蒸気等が残留したガス排気側の清浄でないガスがガラスパイプ内に流入し、コラプス後の光ファイバ母材内に水分や不純物等が取り込まれるおそれがある。このような水分等が取り込まれた母材から光ファイバを作製すると、その光ファイバにおいてはＯＨ基に起因する吸収損失(ＯＨ損失)が大きくなってしまう。   By the way, in the above manufacturing method, when the start of integration is detected, the supply of gas from the gas supply pipe 27 is stopped, and the gas supply side is sucked by the vacuum suction device 47 to start the continuous integration process. For this reason, when the integration at the integration start end is incomplete (a gap is left), the gas is sucked from the gas supply side, so that the unclean gas on the gas exhaust side where water vapor or the like remains is glass. There is a possibility that moisture, impurities, etc. may be taken into the optical fiber preform after collapsing into the pipe. When an optical fiber is manufactured from such a base material in which moisture or the like is taken in, an absorption loss (OH loss) due to the OH group increases in the optical fiber.

本発明の目的は、高品質なガラス母材を円滑に製造することができるガラス母材の製造方法及び製造装置を提供することにある。   The objective of this invention is providing the manufacturing method and manufacturing apparatus of a glass base material which can manufacture a high quality glass base material smoothly.

上記課題を解決することのできる本発明のガラス母材の製造方法は、ガラスロッドを挿入したガラスパイプの一端側からなる１次側にガス供給管を接続するとともに前記ガラスパイプの他端側からなる２次側にガス排気管を接続し、さらに前記ガス供給管から前記ガラスパイプに供給されるガスの余剰分を流すバイパス管を前記ガス供給管と前記ガス排気管との間に接続した状態で、
前記ガラスパイプの軸方向の一部を加熱手段で加熱して前記ガラスパイプの軸方向の一部と前記ガラスロッドの軸方向の一部とを一体化させる始端一体化処理を行い、次いで、前記加熱手段を前記ガラスパイプに対して相対的に移動させて前記ガラスパイプと前記ガラスロッドとを軸方向にわたって一体化させる連続一体化処理を行ってガラス母材を得るガラス母材の製造方法であって、
前記ガラスパイプの１次側圧力を常に２次側圧力以上に維持させながら、前記始端一体化処理及び前記連続一体化処理を行うことを特徴とする。 The method for producing a glass base material of the present invention capable of solving the above-described problem is to connect a gas supply pipe to the primary side consisting of one end side of a glass pipe into which a glass rod is inserted and from the other end side of the glass pipe. A state in which a gas exhaust pipe is connected to the secondary side, and a bypass pipe for passing an excess of gas supplied from the gas supply pipe to the glass pipe is connected between the gas supply pipe and the gas exhaust pipe so,
A starting end integration process is performed in which a part of the glass pipe in the axial direction is heated by a heating means to integrate a part of the glass pipe in the axial direction and a part of the glass rod in the axial direction, A glass base material manufacturing method for obtaining a glass base material by performing a continuous integration process in which a heating means is moved relative to the glass pipe to integrate the glass pipe and the glass rod in the axial direction. And
The starting end integration process and the continuous integration process are performed while the primary pressure of the glass pipe is always maintained to be equal to or higher than the secondary pressure.

本発明のガラス母材の製造方法において、前記ガラスパイプの２次側のみにガス吸引器を設け、前記始端一体化処理時及び前記連続一体化処理時に前記ガス吸引器によって２次側のガスを前記ガス排気管から吸引して前記ガラスパイプの１次側圧力を常に２次側圧力以上に維持させることが好ましい。   In the method for producing a glass base material of the present invention, a gas suction device is provided only on the secondary side of the glass pipe, and the gas on the secondary side is supplied by the gas suction device during the start-end integration processing and the continuous integration processing. It is preferable that the primary pressure of the glass pipe is always maintained at or higher than the secondary pressure by suction from the gas exhaust pipe.

本発明のガラス母材の製造装置は、ガラスパイプにガラスロッドを挿入した状態で加熱し一体化させてガラス母材を製造するガラス母材の製造装置であって、
前記ガラスロッドが挿入された前記ガラスパイプの一端側からなる１次側に接続されるガス供給管と、
前記ガラスパイプの他端側からなる２次側に接続されるガス排気管と、
前記ガス供給管に流量を調整してガスを送り込む流量制御手段と、
前記ガス供給管と前記ガス排気管との間に接続されて前記ガス供給管から前記ガラスパイプに供給されるガスの余剰分を流すバイパス管と、
前記ガラスパイプの軸方向の一部を加熱しながら前記ガラスパイプの軸方向に沿って前記ガラスパイプに対して相対的に移動して前記ガラスパイプと前記ガラスロッドとを一体化させる加熱手段と、
前記ガラスパイプの２次側のみに設けられ、２次側のガスを前記ガス排気管から吸引して前記ガラスパイプの１次側圧力を２次側圧力以上に維持させるガス吸引器と、
を備えることを特徴とする。 The glass base material manufacturing apparatus of the present invention is a glass base material manufacturing apparatus that manufactures a glass base material by heating and integrating in a state where a glass rod is inserted into a glass pipe,
A gas supply pipe connected to a primary side composed of one end side of the glass pipe into which the glass rod is inserted;
A gas exhaust pipe connected to the secondary side consisting of the other end of the glass pipe;
Flow rate control means for adjusting the flow rate to the gas supply pipe and feeding the gas;
A bypass pipe connected between the gas supply pipe and the gas exhaust pipe to flow an excess of gas supplied from the gas supply pipe to the glass pipe;
Heating means for moving the glass pipe and the glass rod together by moving relative to the glass pipe along the axial direction of the glass pipe while heating a part of the glass pipe in the axial direction;
A gas suction device that is provided only on the secondary side of the glass pipe and sucks the gas on the secondary side from the gas exhaust pipe so as to maintain the primary side pressure of the glass pipe at or above the secondary side pressure;
It is characterized by providing.

本発明によれば、ガラスパイプの１次側圧力を常に２次側圧力以上に維持させながら一体化処理を実施する。これにより、ガラスパイプの始端での一体化が不完全であったとしても、ガラスパイプ内で２次側から１次側へガスが流れることはない。したがって、ガラスパイプ内への２次側の排ガスの逆流を防止することができ、水分や不純物の混入を防止して高品質なガラス母材を製造することができる。すなわち、製造したガラス母材から、伝送損失が低く信頼性の高い光ファイバを製造することができる。   According to the present invention, the integration process is performed while the primary pressure of the glass pipe is always maintained at or above the secondary pressure. Thereby, even if integration at the starting end of the glass pipe is incomplete, gas does not flow from the secondary side to the primary side in the glass pipe. Therefore, the backflow of the secondary side exhaust gas into the glass pipe can be prevented, and mixing of moisture and impurities can be prevented and a high-quality glass base material can be manufactured. That is, an optical fiber with low transmission loss and high reliability can be manufactured from the manufactured glass preform.

本発明に係るガラス母材の製造装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the manufacturing apparatus of the glass base material which concerns on this invention. 図１に示した製造装置で一体化処理の開始後における状態を示す概略構成図である。It is a schematic block diagram which shows the state after the start of an integration process with the manufacturing apparatus shown in FIG. 図１の製造装置の変形例を示す概略構成図である。It is a schematic block diagram which shows the modification of the manufacturing apparatus of FIG. 従来のガラス母材の製造装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the manufacturing apparatus of the conventional glass base material.

以下、本発明に係るガラス母材の製造方法及び製造装置の実施の形態の例を、図面を参照して説明する。
図１に示すように、本実施形態に係るガラス母材の製造装置２１は、所謂、ロッドインコラプス法によって所定長のガラス母材を得るものである。 Hereinafter, an example of an embodiment of a glass base material manufacturing method and manufacturing apparatus according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the glass base material manufacturing apparatus 21 according to the present embodiment obtains a glass base material having a predetermined length by a so-called rod-in collapse method.

製造装置２１は、ガラスロッド２３が挿入されたガラスパイプ２５の一端側である１次側にガス供給管２７を気密に接続する管継手としての第１シールボックス２９と、ガラスパイプ２５の他端側である２次側にガス排気管３１を気密に接続する管継手としての第２シールボックス３３とを備えている。これらの第１シールボックス２９及び第２シールボックス３３は、基台３５に支持されており、これにより、内側にガラスロッド２３が挿入されて保持されたガラスパイプ２５が水平に支持される。   The manufacturing apparatus 21 includes a first seal box 29 as a pipe joint that hermetically connects the gas supply pipe 27 to the primary side that is one end side of the glass pipe 25 into which the glass rod 23 is inserted, and the other end of the glass pipe 25. A second seal box 33 is provided as a pipe joint for airtightly connecting the gas exhaust pipe 31 to the secondary side. The first seal box 29 and the second seal box 33 are supported by the base 35, and thereby the glass pipe 25 in which the glass rod 23 is inserted and held is supported horizontally.

製造装置２１は、ガラスパイプ２５を加熱する加熱手段としての加熱炉３７を備えている。加熱炉３７は、ガラスパイプ２５の外周を囲う略環状の炉体３７ａ内に、略環状の加熱ヒータ３７ｂを配置したものであり、ガラスパイプ２５を周方向に略均一に加熱することができる。この加熱炉３７は、図１に矢印Ａで示すように、ガラスパイプ２５の中心軸の方向に沿って移動可能に設置されている。なお、加熱炉３７を固定式にして、ガラスパイプ２５が軸方向に沿って移動する構成としたり、両者が共に相対的に移動する構成としてもよい。   The manufacturing apparatus 21 includes a heating furnace 37 as a heating means for heating the glass pipe 25. The heating furnace 37 is configured by disposing a substantially annular heater 37b in a substantially annular furnace body 37a surrounding the outer periphery of the glass pipe 25, and can heat the glass pipe 25 substantially uniformly in the circumferential direction. The heating furnace 37 is installed so as to be movable along the direction of the central axis of the glass pipe 25 as indicated by an arrow A in FIG. The heating furnace 37 may be fixed and the glass pipe 25 may move along the axial direction, or both may move relatively.

ガス供給管２７には、ガス供給手段（図示省略）が接続されており、このガス供給手段から所定のガスが供給される。ガス供給管２７には、その途中に、ガス供給手段からガス供給管２７へ供給されるガスの流量を制御する流量制御手段（ＭＦＣ）３９が設けられている。   A gas supply means (not shown) is connected to the gas supply pipe 27, and a predetermined gas is supplied from this gas supply means. In the middle of the gas supply pipe 27, a flow rate control means (MFC) 39 for controlling the flow rate of the gas supplied from the gas supply means to the gas supply pipe 27 is provided.

ガス供給手段は、ガラスパイプ２５内にガラスロッド２３を挿入する前にガラスパイプ２５の内周面をエッチング処理する工程で六弗化硫黄（ＳＦ6）等のエッチングガスをガス供給管２７に供給する際や、始端一体化処理を実施する際に、脱水効果の高い塩素（Ｃｌ2）ガス等をガス供給管２７に供給する。 The gas supply means supplies an etching gas such as sulfur hexafluoride (SF 6 ) to the gas supply pipe 27 in the step of etching the inner peripheral surface of the glass pipe 25 before inserting the glass rod 23 into the glass pipe 25. When performing the start end integration process, a chlorine (Cl 2 ) gas having a high dehydrating effect is supplied to the gas supply pipe 27.

ガス供給管２７及びガス排気管３１には、バイパス管４１が接続されている。このバイパス管４１には、ガス供給管２７からガラスパイプ２５内へ供給されるガス圧が一定以上にならないように、ガスの余剰分をバイパス管４１へ逃がすガス量調整弁４３および自動弁４９が設けられている。また、このバイパス管４１の途中には、流れるガス流量を検出するバイパス流量測定手段（ＭＦＭ）４５が設けられている。
また、ガス排気管３１には、ガス吸引器である真空吸引装置４８が接続されており、この真空吸引装置４８は、ガス排気管３１内のガスを吸引する。 A bypass pipe 41 is connected to the gas supply pipe 27 and the gas exhaust pipe 31. The bypass pipe 41 is provided with a gas amount adjusting valve 43 and an automatic valve 49 for releasing excess gas to the bypass pipe 41 so that the gas pressure supplied from the gas supply pipe 27 into the glass pipe 25 does not exceed a certain level. Is provided. In the middle of the bypass pipe 41, a bypass flow rate measuring means (MFM) 45 for detecting the flow rate of the flowing gas is provided.
The gas exhaust pipe 31 is connected to a vacuum suction device 48 that is a gas suction device. The vacuum suction device 48 sucks the gas in the gas exhaust pipe 31.

上記の製造装置２１は、制御装置（ＣＰＵ）６０を備えている。この制御装置６０は、バイパス流量測定手段４５で測定されたガス流量とガス供給管２７から供給するガス流量の差を計算する。   The manufacturing apparatus 21 includes a control device (CPU) 60. The control device 60 calculates the difference between the gas flow rate measured by the bypass flow rate measuring means 45 and the gas flow rate supplied from the gas supply pipe 27.

ガラスパイプ２５は、予め両端にダミーパイプ２６ａ，２６ｂが気密に接合される。そして、１次側のダミーパイプ２６ａが第１シールボックス２９を介してガス供給管２７に接続され、２次側のダミーパイプ２６ｂが第２シールボックス３３を介してガス排気管３１に接続される。   In the glass pipe 25, dummy pipes 26a and 26b are airtightly bonded to both ends in advance. The primary dummy pipe 26 a is connected to the gas supply pipe 27 via the first seal box 29, and the secondary dummy pipe 26 b is connected to the gas exhaust pipe 31 via the second seal box 33. .

両端にダミーパイプ２６ａ，２６ｂが接続されたガラスパイプ２５は、ガラスロッド２３が未挿入の状態で、第１シールボックス２９及び第２シールボックス３３に接続され、その内部にエッチングガスを流すことによって、内周面がエッチングされる。そして、エッチング処理後に、一旦、第１シールボックス２９及び第２シールボックス３３から取り外されて、ガラスロッド２３が挿通されて保持された状態とされ、再度、第１シールボックス２９及び第２シールボックス３３間に取り付けられて、ガラスロッド２３とガラスパイプ２５とを一体化するための始端一体化処理及び連続一体化処理が順次実施される。   The glass pipe 25 having the dummy pipes 26a and 26b connected to both ends is connected to the first seal box 29 and the second seal box 33 with the glass rod 23 not inserted, and an etching gas is caused to flow therein. The inner peripheral surface is etched. After the etching process, the first seal box 29 and the second seal box 33 are once removed and the glass rod 23 is inserted and held. The first seal box 29 and the second seal box are once again held. 33, the start end integration process and the continuous integration process for integrating the glass rod 23 and the glass pipe 25 are sequentially performed.

次に、上記の製造装置２１によるガラス母材の製造方法の手順の一例を説明する。
予め、光ファイバのコア部となるガラスロッド２３と、光ファイバのクラッド部の一部となるガラスパイプ２５を用意しておく。ガラスパイプ２５は、図１に示すように、両端にダミーパイプ２６ａ，２６ｂを接合した状態で用意しておく。 Next, an example of the procedure of the glass base material manufacturing method by the manufacturing apparatus 21 will be described.
A glass rod 23 serving as a core portion of the optical fiber and a glass pipe 25 serving as a part of the clad portion of the optical fiber are prepared in advance. As shown in FIG. 1, the glass pipe 25 is prepared with dummy pipes 26a and 26b joined to both ends.

そして、まず、ガラスパイプ２５の両端のダミーパイプ２６ａ，２６ｂを、第１シールボックス２９及び第２シールボックス３３に取り付けて、ガラスパイプ２５の両端にガス供給管２７及びガス排気管３１が接続された状態にする。   First, dummy pipes 26 a and 26 b at both ends of the glass pipe 25 are attached to the first seal box 29 and the second seal box 33, and the gas supply pipe 27 and the gas exhaust pipe 31 are connected to both ends of the glass pipe 25. To the state.

その後、ガス供給手段、流量制御手段３９、及びガス供給管２７により、ＳＦ6ガス及びＣｌ2ガスをそれぞれ所定の流量で、ガラスパイプ２５に供給し、真空吸引装置４８によりガス排気管３１にガスを引き込む。これにより、ガラスパイプ２５の内部はこれらのガスで置換される。上記のガスを流したまま、加熱炉３７を用いてガラスパイプ２５を加熱し、ガラスパイプ２５の内面をエッチングするエッチング処理を実施する。 Thereafter, SF 6 gas and Cl 2 gas are respectively supplied to the glass pipe 25 at a predetermined flow rate by the gas supply means, the flow rate control means 39 and the gas supply pipe 27, and gas is supplied to the gas exhaust pipe 31 by the vacuum suction device 48. Pull in. Thereby, the inside of the glass pipe 25 is replaced with these gases. An etching process is performed in which the glass pipe 25 is heated using the heating furnace 37 while the gas is flowing, and the inner surface of the glass pipe 25 is etched.

このエッチング処理においては、ガラスパイプ２５における光ファイバの有効部となる範囲において、加熱炉３７をほぼ一定の速度で移動させ、エッチング量がほぼ一定となるようにする。このエッチング処理によりガラスパイプ２５の内径が所定の値となった後、エッチングを終了させる。   In this etching process, the heating furnace 37 is moved at a substantially constant speed in a range that is an effective portion of the optical fiber in the glass pipe 25 so that the etching amount becomes substantially constant. The etching is terminated after the inner diameter of the glass pipe 25 reaches a predetermined value by this etching process.

次いで、第２シールボックス３３をガラスパイプ２５から取り外し、ガラスパイプ２５の内部にガラスロッド２３を挿入して保持させる。
そして、再び第２シールボックス３３をガラスパイプ２５に取り付けた後、ガス供給手段及び、流量制御手段３９、ガス供給管２７により、ガラスパイプ２５内にＣｌ2ガスを供給しながら、真空吸引装置４８でガス排気管３１にガスを引き込む。 Next, the second seal box 33 is removed from the glass pipe 25, and the glass rod 23 is inserted and held inside the glass pipe 25.
Then, after the second seal box 33 is attached to the glass pipe 25 again, the vacuum suction device 48 is supplied while Cl 2 gas is supplied into the glass pipe 25 by the gas supply means, the flow rate control means 39 and the gas supply pipe 27. Then, gas is drawn into the gas exhaust pipe 31.

このようにガラスロッド２３とガラスパイプ２５との間隙部の圧力が外気圧よりも高い場合には、第１シールボックス２９または第２シールボックス３３との接続部から外気がガラスパイプ２５の内部に侵入することが防止される。   Thus, when the pressure in the gap between the glass rod 23 and the glass pipe 25 is higher than the outside air pressure, the outside air enters the inside of the glass pipe 25 from the connecting portion with the first seal box 29 or the second seal box 33. Intrusion is prevented.

そして、ガラスパイプ２５の内部がＣｌ2ガスで十分に置換された後、ガラスパイプ２５の内部の圧力をその外部の圧力より高く保ったまま、ガラスパイプ２５を加熱炉３７で加熱して脱水処理を行う。これにより、ガラスロッド２３の外周面及びガラスパイプ２５の内面に付着した水分を除去する。 Then, after the inside of the glass pipe 25 is sufficiently replaced with Cl 2 gas, the glass pipe 25 is heated in the heating furnace 37 while the pressure inside the glass pipe 25 is kept higher than the pressure outside the glass pipe 25, and dehydration treatment is performed. I do. Thereby, the water | moisture content adhering to the outer peripheral surface of the glass rod 23 and the inner surface of the glass pipe 25 is removed.

その後、自動弁４９を開き、ガラスパイプ２５の２次側の任意の位置(以下、開始位置)でガラスパイプ２５の軸方向の一部とガラスロッド２３の軸方向の一部を加熱して一体化する始端一体化処理を実施する。このとき、ガス供給管２７にはＣｌ2，Ｏ2，Ｎ2等のガスが供給され、ガス供給管２７に供給されたそれらのガスは、まだその全量がガラスパイプ２５側に流れて、ガス排気管３１に排出される。 Thereafter, the automatic valve 49 is opened, and a part of the glass pipe 25 in the axial direction and a part of the glass rod 23 in the axial direction are heated and integrated at an arbitrary position (hereinafter referred to as a starting position) on the secondary side of the glass pipe 25. The starting end integration process is implemented. At this time, gases such as Cl 2 , O 2 , and N 2 are supplied to the gas supply pipe 27, and all of the gases supplied to the gas supply pipe 27 still flow toward the glass pipe 25, It is discharged to the exhaust pipe 31.

始端一体化処理の開始後は、バイパス流量測定手段４５の検出値を監視する。ガラスパイプ２５とガラスロッド２３とが溶着して一体化が始まると、ガラスパイプ２５内の間隙部が絞られた状態になって、ガス排気管３１側へガスが流れにくくなる。そのため、一体化の進行に伴って、ガラスパイプ２５内の圧力が上昇する。これにより、ガラスパイプ２５の１次側圧力Ｐ１が、ガラスパイプ２５の２次側圧力Ｐ２以上に保たれる。   After the start end integration process is started, the detection value of the bypass flow rate measuring means 45 is monitored. When the glass pipe 25 and the glass rod 23 are welded and integration is started, the gap in the glass pipe 25 is narrowed and the gas does not easily flow to the gas exhaust pipe 31 side. Therefore, the pressure in the glass pipe 25 increases with the progress of integration. Thereby, the primary side pressure P1 of the glass pipe 25 is kept more than the secondary side pressure P2 of the glass pipe 25.

そして、ガラスパイプ２５の１次側圧力Ｐ１が上昇し、予め設定した基準の圧力を越える余剰分のガスは、バイパス管４１に流れるようになる。即ち、始端一体化の進行に伴って、バイパス管４１に流れるガス量が増加していくことになり、バイパス管４１に流れるガス量を監視することで、始端一体化の進行状態を検知することができる。   Then, the primary pressure P1 of the glass pipe 25 increases, and surplus gas exceeding the preset reference pressure flows to the bypass pipe 41. That is, as the start-end integration progresses, the amount of gas flowing to the bypass pipe 41 increases, and the progress of the start-end integration is detected by monitoring the amount of gas flowing to the bypass pipe 41. Can do.

始端一体化処理の開始後、一体化の進行に応じてガス供給管２７からバイパス管４１へのガスの流入量が増え始めた後も、真空吸引装置４８によってガラスパイプ２５の２次側のガスをガス排気管３１へ引き込み、常に、ガラスパイプ２５の１次側圧力Ｐ１を２次側圧力Ｐ２以上となるように維持する。   After the start-end integration process is started, the gas on the secondary side of the glass pipe 25 is also collected by the vacuum suction device 48 after the inflow of gas from the gas supply pipe 27 to the bypass pipe 41 starts to increase as the integration progresses. Is drawn into the gas exhaust pipe 31, and the primary pressure P1 of the glass pipe 25 is always maintained to be equal to or higher than the secondary pressure P2.

なお、一体化の進行に応じてガス供給管２７からバイパス管４１へのガスの流入量が増え始めた後は、流量制御手段３９によって徐々にガス供給管２７へのガス供給量を減少させたり、ガラスパイプ２５の１次側圧力Ｐ１及び２次側圧力Ｐ２の条件を変更したりして、必要以上の圧力がガラスパイプ２５に作用しないようにしてもよい。また、ガス供給手段から供給するガスの種類を変更しても良い。   In addition, after the inflow of gas from the gas supply pipe 27 to the bypass pipe 41 starts to increase with the progress of integration, the gas supply quantity to the gas supply pipe 27 is gradually decreased by the flow rate control means 39. The conditions of the primary side pressure P1 and the secondary side pressure P2 of the glass pipe 25 may be changed so that an unnecessary pressure does not act on the glass pipe 25. Moreover, you may change the kind of gas supplied from a gas supply means.

始端一体化処理による一体化がガラスパイプ２５の周方向にわたって完了すると、その部分のガラスパイプ２５の内側は封止されてガラスパイプ２５からガス排気管３１側へガスが通過することができない。そのため、ガス供給管２７に供給されたガス量は、全量がバイパス管４１に流れることになる。   When the integration by the start end integration process is completed in the circumferential direction of the glass pipe 25, the inside of the glass pipe 25 at that portion is sealed, and gas cannot pass from the glass pipe 25 to the gas exhaust pipe 31 side. Therefore, the total amount of gas supplied to the gas supply pipe 27 flows to the bypass pipe 41.

そこで、バイパス流量測定手段４５を監視していて、ガス供給管２７に供給されたガス量の全量がバイパス管４１に流れた時、始端一体化処理が完了したとみなすことができる。   Therefore, when the bypass flow rate measuring means 45 is monitored and the entire amount of the gas supplied to the gas supply pipe 27 flows to the bypass pipe 41, it can be considered that the start end integration process has been completed.

始端一体化処理が完了した後、図２に示すように、一体化の開始位置からガラスパイプ２５の１次側に加熱炉３７を徐々に移動させて、ガラスパイプ２５を収縮（所謂、コラプス）させることで、ガラスパイプ２５とガラスロッド２３との加熱一体化域を１次側に延長して軸方向にわたって一体化させる連続一体化処理を実施する。これにより、ガラスパイプ２５及びガラスロッド２３の両者が所定の長さにわたって一体化される。   After the start end integration process is completed, as shown in FIG. 2, the heating furnace 37 is gradually moved from the integration start position to the primary side of the glass pipe 25 to shrink the glass pipe 25 (so-called collapse). Thus, a continuous integration process is performed in which the heating integrated region of the glass pipe 25 and the glass rod 23 is extended to the primary side and integrated in the axial direction. Thereby, both the glass pipe 25 and the glass rod 23 are integrated over predetermined length.

この連続一体化処理時においても、真空吸引装置４８によってガラスパイプ２５の２次側のガスをガス排気管３１へ引き込み、常に、ガラスパイプ２５の１次側圧力Ｐ１を２次側圧力Ｐ２以上になるように維持する。   Even during this continuous integration process, the secondary side gas P1 of the glass pipe 25 is drawn into the gas exhaust pipe 31 by the vacuum suction device 48, and the primary side pressure P1 of the glass pipe 25 is always higher than the secondary side pressure P2. To keep.

このように、本実施形態では、ガラスパイプ２５の１次側圧力Ｐ１を常に２次側圧力Ｐ２以上に維持させながら始端一体化処理及び連続一体化処理を実施する。そのため、始端一体化処理の際、ガラスパイプ２５とガラスロッド２３との一体化が不完全となっても、ガラスパイプ２５内で２次側から１次側へガスが流れることはない。したがって、ガラスパイプ２５内への２次側の排ガスの逆流を防止することができ、水分や不純物の混入を防止して高品質なガラス母材を製造することができる。これにより、製造したガラス母材から、伝送損失が低く信頼性の高い光ファイバを製造することができる。   As described above, in the present embodiment, the starting end integration process and the continuous integration process are performed while the primary pressure P1 of the glass pipe 25 is constantly maintained at the secondary pressure P2 or higher. Therefore, even when the integration of the glass pipe 25 and the glass rod 23 is incomplete during the start-end integration process, gas does not flow from the secondary side to the primary side in the glass pipe 25. Accordingly, the backflow of the secondary side exhaust gas into the glass pipe 25 can be prevented, and mixing of moisture and impurities can be prevented and a high-quality glass base material can be manufactured. Thereby, an optical fiber with low transmission loss and high reliability can be manufactured from the manufactured glass preform.

さらに、上記の製造装置２１では、始端一体化処理時及び連続一体化処理時に２次側のガスを吸引するガス吸引器として、ガラスパイプ２５の２次側のみに真空吸引装置４８を設けたので、１次側のガスを吸引して圧力調整を行う従来例である図４の製造装置と比較して、１次側のガス吸引器及びガス処理装置を不要とすることができ、装置の大幅なコスト削減を図ることができる。   Further, in the manufacturing apparatus 21 described above, the vacuum suction device 48 is provided only on the secondary side of the glass pipe 25 as a gas suction device that sucks the secondary side gas during the start-end integration process and the continuous integration process. Compared with the manufacturing apparatus of FIG. 4 which is a conventional example in which the pressure is adjusted by sucking the primary side gas, the primary side gas suction device and the gas processing apparatus can be dispensed with. Cost reduction can be achieved.

なお、上記の製造装置２１では、２次側に設けた一つの真空吸引装置４８でガス排気管３１へのガスの引き込みを行うようにしたが、図３に示す製造装置２１Ａのように、真空吸引装置４８とは別の強吸引用の真空ポンプ５１を設け、始端一体化処理後における連続一体化処理での２次側のガスの吸引時に、真空ポンプ５１の上流側に設けられたバルブ５２を開いて真空ポンプ５１を作動させ、２次側のガスの吸引を真空吸引装置４８より吸引力の強い真空ポンプ５１で行っても良い。   In the manufacturing apparatus 21 described above, gas is drawn into the gas exhaust pipe 31 by one vacuum suction device 48 provided on the secondary side. However, as in the manufacturing apparatus 21A shown in FIG. A vacuum pump 51 for strong suction different from the suction device 48 is provided, and a valve 52 provided on the upstream side of the vacuum pump 51 at the time of suction of the secondary gas in the continuous integration process after the start end integration process. May be opened and the vacuum pump 51 may be operated to suck the secondary gas with the vacuum pump 51 having a stronger suction than the vacuum suction device 48.

このように、真空吸引装置４８と真空ポンプ５１を適宜併用して始端一体化処理と連続一体化処理での吸引を行うことにより、連続一体化処理で１次側と２次側との圧力調整を高精度に行うことができる。なお、始端一体化処理後における連続一体化処理での吸引の際に、真空吸引装置４８による吸引と真空ポンプ５１による吸引を両方行うようにしても良い。   In this way, the vacuum suction device 48 and the vacuum pump 51 are appropriately used together to perform suction in the start end integration process and the continuous integration process, thereby adjusting the pressure on the primary side and the secondary side in the continuous integration process. Can be performed with high accuracy. Note that both suction by the vacuum suction device 48 and suction by the vacuum pump 51 may be performed during suction in the continuous integration process after the start-end integration process.

２１，２１Ａ：製造装置、２３：ガラスロッド、２５：ガラスパイプ、２７：ガス供給管、３１：ガス排気管、３７：加熱炉（加熱手段）、３９：流量制御手段、４１：バイパス管、４８：真空吸引装置（ガス吸引器）、５１：真空ポンプ（ガス吸引器）、Ｐ１：１次側圧力、Ｐ２：２次側圧力 21, 21A: Manufacturing apparatus, 23: Glass rod, 25: Glass pipe, 27: Gas supply pipe, 31: Gas exhaust pipe, 37: Heating furnace (heating means), 39: Flow control means, 41: Bypass pipe, 48 : Vacuum suction device (gas suction device), 51: Vacuum pump (gas suction device), P1: Primary pressure, P2: Secondary pressure

Claims (3)

ガラスロッドを挿入したガラスパイプの一端側からなる１次側にガス供給管を接続するとともに前記ガラスパイプの他端側からなる２次側にガス排気管を接続し、さらに前記ガス供給管から前記ガラスパイプに供給されるガスの余剰分を流すバイパス管を前記ガス供給管と前記ガス排気管との間に接続した状態で、
前記ガラスパイプの軸方向の一部を加熱手段で加熱して前記ガラスパイプの軸方向の一部と前記ガラスロッドの軸方向の一部とを一体化させる始端一体化処理を行い、次いで、前記加熱手段を前記ガラスパイプに対して相対的に移動させて前記ガラスパイプと前記ガラスロッドとを軸方向にわたって一体化させる連続一体化処理を行ってガラス母材を得るガラス母材の製造方法であって、
前記ガラスパイプの１次側圧力を常に２次側圧力以上に維持させながら、前記始端一体化処理及び前記連続一体化処理を行うことを特徴とするガラス母材の製造方法。 A gas supply pipe is connected to the primary side consisting of one end of the glass pipe into which the glass rod is inserted, and a gas exhaust pipe is connected to the secondary side consisting of the other end of the glass pipe. In a state where a bypass pipe for flowing excess gas supplied to the glass pipe is connected between the gas supply pipe and the gas exhaust pipe,
A starting end integration process is performed in which a part of the glass pipe in the axial direction is heated by a heating means to integrate a part of the glass pipe in the axial direction and a part of the glass rod in the axial direction, A glass base material manufacturing method for obtaining a glass base material by performing a continuous integration process in which a heating means is moved relative to the glass pipe to integrate the glass pipe and the glass rod in the axial direction. And
The method for producing a glass base material, wherein the starting end integration process and the continuous integration process are performed while the primary pressure of the glass pipe is always maintained to be equal to or higher than the secondary pressure. 請求項１に記載のガラス母材の製造方法であって、
前記ガラスパイプの２次側のみにガス吸引器を設け、前記始端一体化処理時及び前記連続一体化処理時に前記ガス吸引器によって２次側のガスを前記ガス排気管から吸引して前記ガラスパイプの１次側圧力を常に２次側圧力以上に維持させることを特徴とするガラス母材の製造方法。 It is a manufacturing method of the glass base material of Claim 1,
A gas suction device is provided only on the secondary side of the glass pipe, and the glass pipe sucks the secondary side gas from the gas exhaust pipe by the gas suction device during the start end integration process and the continuous integration process. A method for producing a glass base material, characterized in that the primary pressure is always maintained to be equal to or higher than the secondary pressure. ガラスパイプにガラスロッドを挿入した状態で加熱し一体化させてガラス母材を製造するガラス母材の製造装置であって、
前記ガラスロッドが挿入された前記ガラスパイプの一端側からなる１次側に接続されるガス供給管と、
前記ガラスパイプの他端側からなる２次側に接続されるガス排気管と、
前記ガス供給管に流量を調整してガスを送り込む流量制御手段と、
前記ガス供給管と前記ガス排気管との間に接続されて前記ガス供給管から前記ガラスパイプに供給されるガスの余剰分を流すバイパス管と、
前記ガラスパイプの軸方向の一部を加熱しながら前記ガラスパイプの軸方向に沿って前記ガラスパイプに対して相対的に移動して前記ガラスパイプと前記ガラスロッドとを一体化させる加熱手段と、
前記ガラスパイプの２次側のみに設けられ、２次側のガスを前記ガス排気管から吸引して前記ガラスパイプの１次側圧力を２次側圧力以上に維持させるガス吸引器と、
を備えることを特徴とするガラス母材の製造装置。 A glass base material manufacturing apparatus for manufacturing a glass base material by heating and integrating with a glass rod inserted into a glass pipe,
A gas supply pipe connected to a primary side composed of one end side of the glass pipe into which the glass rod is inserted;
A gas exhaust pipe connected to the secondary side consisting of the other end of the glass pipe;
Flow rate control means for adjusting the flow rate to the gas supply pipe and feeding the gas;
A bypass pipe connected between the gas supply pipe and the gas exhaust pipe to flow an excess of gas supplied from the gas supply pipe to the glass pipe;
Heating means for moving the glass pipe and the glass rod together by moving relative to the glass pipe along the axial direction of the glass pipe while heating a part of the glass pipe in the axial direction;
A gas suction device that is provided only on the secondary side of the glass pipe and sucks the gas on the secondary side from the gas exhaust pipe so as to maintain the primary side pressure of the glass pipe at or above the secondary side pressure;
An apparatus for producing a glass base material, comprising:
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Publication number Priority date Publication date Assignee Title
CN113248134A (en) * 2021-06-03 2021-08-13 武汉光盛通光电科技有限公司 Pressure adjusting device and method for rod making equipment by using in-pipe method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113248134A (en) * 2021-06-03 2021-08-13 武汉光盛通光电科技有限公司 Pressure adjusting device and method for rod making equipment by using in-pipe method

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