JP4435390B2 - Heat shield cylinder, glass base material manufacturing apparatus and method including the same - Google Patents

Heat shield cylinder, glass base material manufacturing apparatus and method including the same Download PDF

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JP4435390B2
JP4435390B2 JP2000234678A JP2000234678A JP4435390B2 JP 4435390 B2 JP4435390 B2 JP 4435390B2 JP 2000234678 A JP2000234678 A JP 2000234678A JP 2000234678 A JP2000234678 A JP 2000234678A JP 4435390 B2 JP4435390 B2 JP 4435390B2
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base material
heat shield
glass base
heat
porous glass
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JP2002047014A (en
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哲也 乙坂
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Shin Etsu Chemical Co 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
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • C03B37/0146—Furnaces therefor, e.g. muffle tubes, furnace linings
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/01486—Means for supporting, rotating or translating the preforms being formed, e.g. lathes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

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  • Engineering & Computer Science (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Glass Melting And Manufacturing (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、多孔質ガラス母材を反応容器内で加熱処理し、透明ガラス化を行ってガラス母材、特には、線引きして光ファイバを得るのに好適なガラス母材の製造に際して用いられる遮熱筒、これを備えたガラス母材の製造装置及び製造方法に関する。
【０００２】
【従来の技術】
ＶＡＤ法やＯＶＤ法による多孔質ガラス母材の製造は、ＳｉＣｌ4，ＧｅＣｌ4などの原料ガスを酸素・水素火炎中に供給して火炎加水分解反応により生成するガラス微粒子 (スート)をダミー棒もしくはコアとなる出発ターゲット棒に堆積させて多孔質ガラス母材（スート堆積体）を合成し、さらに１,５００℃程度の温度で脱水、透明ガラス化してガラス母材を得ている。
特に、光ファイバ用ガラス母材の合成は、透明ガラス化中、あるいは透明ガラス化処理に先立って、多孔質ガラス母材を塩素を含む脱水ガス雰囲気中で加熱することにより、光ファイバの伝送損失の要因となる水酸基を除去する脱水処理を行っている。
【０００３】
多孔質ガラス母材の透明ガラス化処理を、図４を用いて説明する。
多孔質ガラス母材１をシャフト２に接続部３で接続し、炉芯管４内にセットする。その後、回転モータ５により、シャフト２を介して多孔質ガラス母材１を回転させつつ引き下げ、加熱器６で加熱し、脱水、透明ガラス化を行う。このとき、ガス導入口７よりＨｅ，Ｃｌ2等の焼結ガスを供給し、排気口８より排気する。なお、ここでは多孔質ガラス母材１を引き下げつつ、多孔質ガラス母材１の下部から透明ガラス化する方法を示したが、多孔質ガラス母材１を加熱器６より下方に一旦降ろしてから、引き上げつつ多孔質ガラス母材１の上部からガラス化を行う方法もある。また、多孔質ガラス母材１の吊り下げ部は、多孔質ガラス母材製造時の石英ガラスからなるダミー棒もしくは出発ターゲット棒（以下、単に石英ロッドという）９が吊り下げ部材としての役割を担っている。
【０００４】
図５および図６に、多孔質ガラス母材上部の石英ロッド９とシャフト２との接続の例を示す。
図５は、石英ロッド９の上端部にくさび部１０を設け、シャフト２の下端部に取り付けられたシャフト管１１の中にくさび部１０を差し込み、シャフト管１１の側面にあけられた穴１２にピン１３を差し込むことで接続している。
図６の接続例は、石英ロッド９の上端に凸部１４を設け、シャフト２の下端に取り付けられた嵌合部材１５の嵌合部１６に、凸部１４を嵌め合わせるものである。
シャフト２、シャフト管１１および嵌合部材１５には、耐熱性、耐熱衝撃性、耐塩素性等が要求されるため、これらの特性を満たすＳｉ3Ｎ4が用いられることが多い。
【０００５】
透明ガラス化の進行にともない、接続部3が加熱器６およびその周囲の断熱材等の高温体に接近すると、接続部3の温度は上がり高くなる。Ｓｉ3Ｎ4と石英ガラスの熱膨張率を比較すると、Ｓｉ3Ｎ4の方が大きいため、接続部3が高温になると、図５の接続構成では、シャフト管１１がより大きく膨張し、くさび部１０は矢印１７の方向にずれ石英ロッド９が下がる。この後、透明ガラス化が終了して接続部３が高温体から遠ざけられ、接続部3の温度が下がると、シャフト管１１は収縮し、くさび部１０がピン１３とシャフト管１１の間で圧縮力を受け、くさび部１０やシャフト管１１、ピン１３等が破損する。このような現象を「焼きばめ」と称している。
【０００６】
図６の接続構成においても高温体への接近・離間があると、同様に焼きばめが起こり、凸部１４や嵌合部１６が破損する。これらの破損にともない、高温の多孔質ガラス母材（あるいは、透明ガラス化されたガラス母材）は落下し、炉芯管や加熱器等の破損を引き起こす。これは非常に危険であり、かつ製造コストを押し上げる。
従来、このような焼きばめによる事故を防ぐため、多孔質ガラス母材の上端から接続部までの距離を十分に離し、接続部が高温にならないようにしていた。
【０００７】
しかしながら、ＯＶＤ法で多孔質ガラス母材を合成しガラス化する場合、上記したように、シャフトとの接続部から、ガラス化される多孔質ガラス母材有効部の上端位置までの距離がかなり必要とされるため、図７（ａ）に示すように、チャック間距離１８に対してガラス化される多孔質ガラス母材１の有効部１９の長さが相対的に短くなるが、接続部３と有効部１９の上端位置までの距離２０を短くすることができれば、図７（ｂ）に示すように、チャック間距離１８を十分に活用してガラス微粒子堆積用バーナ２１の移動範囲を広げることができ、より長尺の多孔質ガラス母材１を合成してガラス化することができ、多孔質ガラス母材１の全長に対する有効部１９の比率が上がり、製品になり得ず廃棄処分されるテーパー部２２の比率を相対的に下げることができる。
【０００８】
【発明が解決しようとする課題】
本発明は、上記事情に鑑みてなされたものであり、多孔質ガラス母材を吊り下げるシャフトと多孔質ガラス母材上部の石英ロッドとの接続部の温度上昇を抑えることができ、接続部から多孔質ガラス母材の有効部までの距離を短くすることのできるガラス母材を得るのに好適な遮熱筒、これを備えたガラス母材の製造装置及び製造方法を提供することを課題としている。
【０００９】
【課題を解決するための手段】
本発明の遮熱筒は、反応容器内に吊り下げられた多孔質ガラス母材を加熱処理し、透明ガラス化を行う装置において、多孔質ガラス母材を吊り下げるシャフトと、多孔質ガラス母材上部の石英ロッドとの接続部が加熱手段および周囲の高温体から受ける輻射熱量を低減するために、該接続部近傍に設けられた筒状の接続部遮熱部材であり、該遮熱筒は有底筒状のもの、あるいは無底で下部からの輻射熱を防ぐための遮熱板上に設けられていることを特徴としている。
なお、この遮熱筒は、耐熱性および耐塩素性を有する素材、例えば、表面をサンドブラスト処理された石英ガラス、不透明石英ガラス、Ｓｉ3Ｎ4等を用いて形成し、接続部近傍の周囲を取り囲むように設けるのが好ましい。
本発明のガラス母材の製造装置は、反応容器内に吊り下げられた多孔質ガラス母材を加熱処理し、透明ガラス化を行う装置であって、多孔質ガラス母材を吊り下げるシャフトと多孔質ガラス母材上部の石英ロッドとの接続部が加熱手段および周囲の高温体から受ける輻射熱量を低減するため、該接続部近傍に遮熱筒を備えたものであり、該遮熱筒は接続部を覆うように設けられる。なお、遮熱筒は有底筒状のものとするか、あるいは無底で下部からの輻射熱を防ぐための遮熱板上に設けてもよい。
本発明のガラス母材の製造方法は、このような製造装置を用いて製造するものである。
【００１０】
【発明の実施の形態】
図１〜図３を用いて本発明のガラス母材の製造装置をさらに詳細に説明する。
図１は、本発明のガラス母材の製造装置を示す概略断面図であり、多孔質ガラス母材１は炉心管４内にセットされ、遮熱筒２３が、多孔質ガラス母材上部の石英ロッド９とシャフト２との接続部３を覆うように設けられている。多孔質ガラス母材１は、回転モータ５によってシャフト２によって回転しつつ引き下げられ、加熱器６で加熱されて透明ガラス化が行われる。この間、ガス導入口７からＨｅ等の焼結ガスが供給され、排気口８から排気される。
【００１１】
遮熱筒２３は、石英ロッド９に形成された凸部２４上に、接続部３を覆うように装着される。このとき、凸部２４の上部に平面部を設け、遮熱筒２３と凸部２４の間に焼きばめが起こらないように装着するのが望ましい。遮熱筒２３は、接続部３が受ける、加熱器６やその周囲に配設された断熱材等の高温体による下方および側方からの輻射熱を遮るのに十分な大きさとする必要がある。
【００１２】
図２に示す態様は、石英ロッド９に形成された凸部２４上に遮熱板２５を配設し、この上に遮熱筒２３を設けたものであり、下方からの熱の多くは遮熱板２５で遮ぎられるため、さらに接続部３に対する遮熱性能が向上し、接続部への熱負荷が低減する。この場合、遮熱筒自体には、下方からの輻射熱を遮る手段を設けなくてもよい。遮熱筒２３と遮熱板２５の併用は、図１に示した遮熱筒２３のみを使用する態様よりもさらに有効である。
【００１３】
図３に、本発明の遮熱筒２３の構造の一例を示す。
多孔質ガラス母材上部の石英ロッドとシャフトを接続した後、接続部を覆うように接続部近傍に、石英ロッドに設けられた凸部上に３面遮熱部品２６を装着し、これに１面遮熱部品２７を引っ掛けるようにして取り付ける。３面遮熱部品２６と１面遮熱部品２７との隙間を通って輻射熱が接続部近傍に到達しないように、１面遮熱部品２７には輻射熱漏入防止板２８が設けられている。遮熱筒２３の上方は開放され、内部に熱がこもらない構造になっている。
【００１４】
遮熱筒および遮熱板には、輻射熱遮蔽能が要求されるため、耐熱性、耐熱衝撃性、耐塩素性を有する材質のものが使用される。これらの要求を満たすものとしてＳｉ3Ｎ4が挙げられるが、Ｓｉ3Ｎ4は比較的高価な材質であり、これに代るものとして、不透明石英ガラスや、より安価なものとして石英ガラス表面にサンドブラスト処理を施したもの等を用いることもできる。
なお、遮熱筒は、接続部遮熱部材として設置されるものであり、その形状は接続部の周囲を取り囲むものであれば、円柱状、楕円柱状、角柱状のいずれであってもよい。また、遮熱筒の底部は有底とするが、遮熱板上に設置する場合は、無底のものであってもよい。
【００１５】
【実施例】
以下に、本発明の実施例、比較例を示すが、本発明はこれらに限定されるものではなく、様々な態様が可能である。
（実施例１）
ＯＶＤ法によって合成した直胴部の直径３５０ｍｍφ、長さ１,９００ｍｍ、シャフトとの接続部下端から直胴部上端までの距離が５００ｍｍの多孔質ガラス母材を、図５に示したくさび方式を用いて多孔質ガラス母材上部の石英ロッドと、回転自在に設けられたシャフトとを接続し、遮熱板および遮熱筒を装着して、図２に示すヒータ長４００ｍｍの加熱手段を有する装置を用いて透明ガラス化した。このようにして多孔質ガラス母材の直胴部上端が、ヒータ上端から２００ｍｍ下の位置まで来るようにして、２０本の多孔質ガラス母材の焼結、ガラス化を行ったが、焼きばめは起こらず、シャフト管、ピン、くさび部のいずれにも損傷はなかった。
【００１６】
（比較例１）
ＯＶＤ法によって合成した直胴部の直径３５０ｍｍφ、長さ１,９００ｍｍ、接続部下端から直胴部上端までの距離が５００ｍｍの多孔質ガラス母材を、図４に示すヒータ長４００ｍｍの加熱手段を有する装置を用い、遮熱板および遮熱筒を装着せずに、図５に示したくさび方式を用いて多孔質ガラス母材上部の石英ロッドとシャフトとを接続し、焼結、ガラス化を行った。このとき、多孔質ガラス母材の直胴部上端が、ヒータ上端から１５０ｍｍ下の位置まで来たところで、焼きばめが起こり、シャフト管に亀裂が入った。
【００１７】
【発明の効果】
本発明によれば、多孔質ガラス母材とシャフトとの接続部を覆うように接続部近傍に有底の遮熱筒を設けたことにより、もしくは遮熱板上に遮熱筒を設けたことにより、ヒータや断熱材等から受ける輻射熱が低減し、接続部の温度上昇が抑制され、焼きばめは防止される。これにより、接続部から母材有効部上端までの距離を、従来よりも短くすることができる。その分、多孔質ガラス母材の有効長を長くすることができ、廃棄されるテーパー部の比率が相対的に減り、収率が向上し、生産性が向上した。
【図面の簡単な説明】
【図１】 本発明のガラス母材の製造装置を示す概略縦断面図である。
【図２】 図１とは異なる態様のガラス母材の製造装置を示す概略縦断面図である。
【図３】 本発明の遮熱筒の構造の一例を示す概略斜視図である。
【図４】 多孔質ガラス母材の透明ガラス化処理を説明する概略縦断面図である。
【図５】 多孔質ガラス母材とシャフトとの接続例を示す部分概略縦断面図である。
【図６】 多孔質ガラス母材とシャフトとの接続例を示す部分概略縦断面図である。
【図７】 （ａ），（ｂ）は、多孔質ガラス母材の有効部の比率を説明する概略縦断面図である。
【符号の説明】
１． 多孔質ガラス母材
２． シャフト
３． 接続部
４． 炉芯管
５． 回転モータ
６． 加熱器
７． ガス導入口
８． 排気口
９． 石英ロッド
１０． くさび部
１１． シャフト管
１２． 穴
１３． ピン
１４． 凸部
１５． 嵌合部材
１６． 嵌合部
１７． 矢印
１８． チャック間距離
１９． 有効部
２０． 距離
２１． ガラス微粒子堆積用バーナ
２２． テーパー部
２３． 遮熱筒
２４． 凸部
２５． 遮熱板
２６． ３面遮熱部品
２７． １面遮熱部品
２８． 輻射熱漏入防止板[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is used for producing a glass preform suitable for obtaining an optical fiber by drawing a porous glass preform in a reaction vessel and carrying out transparent vitrification to draw an optical fiber. The present invention relates to a heat shield tube, a glass base material manufacturing apparatus and a manufacturing method including the same.
[0002]
[Prior art]
The porous glass base material is manufactured by the VAD method or the OVD method by supplying a raw material gas such as SiCl 4 or GeCl 4 into an oxygen / hydrogen flame to generate glass fine particles (soot) generated by a flame hydrolysis reaction with a dummy rod or A porous glass base material (soot deposit) is synthesized by depositing on a starting target rod as a core, and further dehydrated at a temperature of about 1500 ° C. to form a transparent glass to obtain a glass base material.
In particular, the synthesis of a glass preform for an optical fiber involves the transmission loss of an optical fiber by heating the porous glass preform in a dehydrated gas atmosphere containing chlorine during or prior to transparent vitrification. Dehydration treatment is performed to remove the hydroxyl group that causes the above.
[0003]
The transparent vitrification treatment of the porous glass base material will be described with reference to FIG.
The porous glass base material 1 is connected to the shaft 2 at the connection portion 3 and set in the furnace core tube 4. After that, the rotary motor 5 is pulled down while rotating the porous glass base material 1 through the shaft 2 and heated by the heater 6 to perform dehydration and transparent vitrification. At this time, a sintering gas such as He and Cl 2 is supplied from the gas inlet 7 and exhausted from the exhaust port 8. In addition, although the method of transparent-glass-forming from the lower part of the porous glass base material 1 was shown here pulling down the porous glass base material 1, after lowering the porous glass base material 1 downward from the heater 6 once. There is also a method of vitrifying from the upper part of the porous glass base material 1 while pulling up. In addition, the suspension portion of the porous glass base material 1 has a dummy rod or a starting target rod (hereinafter simply referred to as a quartz rod) 9 made of quartz glass at the time of manufacturing the porous glass base material serving as a suspension member. ing.
[0004]
5 and 6 show examples of connection between the quartz rod 9 and the shaft 2 on the upper part of the porous glass base material.
In FIG. 5, a wedge portion 10 is provided at the upper end portion of the quartz rod 9, the wedge portion 10 is inserted into the shaft tube 11 attached to the lower end portion of the shaft 2, and the hole 12 formed in the side surface of the shaft tube 11 is inserted. It is connected by inserting the pin 13.
In the connection example of FIG. 6, the convex portion 14 is provided at the upper end of the quartz rod 9, and the convex portion 14 is fitted into the fitting portion 16 of the fitting member 15 attached to the lower end of the shaft 2.
Since the shaft 2, the shaft tube 11, and the fitting member 15 are required to have heat resistance, thermal shock resistance, chlorine resistance, and the like, Si 3 N 4 that satisfies these characteristics is often used.
[0005]
As the transparent vitrification progresses, the temperature of the connecting portion 3 increases as the connecting portion 3 approaches a high-temperature body such as the heater 6 and the surrounding heat insulating material. Comparing the thermal expansion coefficients of Si 3 N 4 and quartz glass, Si 3 N 4 is larger. Therefore, when the connecting portion 3 becomes hot, the shaft tube 11 expands more greatly in the connection configuration shown in FIG. The part 10 is displaced in the direction of the arrow 17 and the quartz rod 9 is lowered. Thereafter, when the transparent vitrification is completed and the connecting portion 3 is moved away from the high temperature body and the temperature of the connecting portion 3 is lowered, the shaft tube 11 contracts and the wedge portion 10 is compressed between the pin 13 and the shaft tube 11. Due to the force, the wedge portion 10, the shaft tube 11, the pin 13, and the like are damaged. Such a phenomenon is called “shrink fit”.
[0006]
In the connection configuration of FIG. 6, if there is an approach / separation to a high temperature body, shrink fitting similarly occurs, and the convex portion 14 and the fitting portion 16 are damaged. Along with these damages, the high-temperature porous glass base material (or the glass base material made into transparent glass) falls, causing damage to the furnace core tube and the heater. This is very dangerous and increases manufacturing costs.
Conventionally, in order to prevent such an accident caused by shrink fitting, the distance from the upper end of the porous glass base material to the connection portion is sufficiently separated so that the connection portion does not become hot.
[0007]
However, when the porous glass base material is synthesized and vitrified by the OVD method, as described above, a considerable distance from the connecting portion with the shaft to the upper end position of the porous glass base material effective portion to be vitrified is necessary. Therefore, as shown in FIG. 7A, the length of the effective portion 19 of the porous glass base material 1 that is vitrified with respect to the inter-chuck distance 18 is relatively short. If the distance 20 to the upper end position of the effective portion 19 can be shortened, as shown in FIG. 7B, the distance 18 between the chucks can be fully utilized to widen the moving range of the glass particle deposition burner 21. The longer porous glass base material 1 can be synthesized and vitrified, and the ratio of the effective portion 19 to the entire length of the porous glass base material 1 is increased, so that it cannot be a product and is discarded. The ratio of the taper part 22 It can be reduced to a pair manner.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and can suppress an increase in the temperature of the connection portion between the shaft that suspends the porous glass base material and the quartz rod on the porous glass base material. An object of the present invention is to provide a heat shield tube suitable for obtaining a glass base material capable of shortening the distance to the effective portion of the porous glass base material, a glass base material manufacturing apparatus and a manufacturing method including the same. Yes.
[0009]
[Means for Solving the Problems]
The heat shield cylinder of the present invention includes a shaft for suspending a porous glass base material and a porous glass base material in an apparatus for heat-treating the porous glass base material suspended in a reaction vessel and converting into a transparent glass. for connection of the upper portion of the quartz rod to reduce the radiation heat amount received from the heating means and the surrounding high-temperature body, a tubular connecting portion heat insulating member provided in the vicinity of the connecting portion, shielding heat barrel It is characterized by being provided with a bottomed cylindrical shape or a heat shield for preventing radiant heat from the bottom without bottom.
The heat shield cylinder is formed of a material having heat resistance and chlorine resistance, for example, quartz glass, opaque quartz glass, Si 3 N 4 or the like whose surface is sandblasted, and the periphery of the connection portion is formed. It is preferable to provide it so as to surround it.
An apparatus for producing a glass base material according to the present invention is an apparatus for heat-treating a porous glass base material suspended in a reaction vessel to form a transparent glass, and a shaft and a porous member for suspending the porous glass base material. In order to reduce the amount of radiant heat received from the heating means and the surrounding high-temperature body at the connection part with the quartz rod on the upper part of the glass base material, a heat shield cylinder is provided in the vicinity of the connection part. It is provided so as to cover the part. The heat shield cylinder may be a bottomed cylinder, or may be provided on a heat shield plate without bottom to prevent radiant heat from the lower part.
The manufacturing method of the glass base material of this invention manufactures using such a manufacturing apparatus.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The glass base material manufacturing apparatus of the present invention will be described in more detail with reference to FIGS.
FIG. 1 is a schematic cross-sectional view showing a glass base material manufacturing apparatus according to the present invention, in which a porous glass base material 1 is set in a furnace core tube 4, and a heat shield cylinder 23 is formed on quartz above the porous glass base material. It is provided so as to cover the connecting portion 3 between the rod 9 and the shaft 2. The porous glass base material 1 is pulled down while being rotated by the shaft 2 by the rotary motor 5, and is heated by the heater 6 to be transparent vitrified. During this time, a sintering gas such as He is supplied from the gas introduction port 7 and is exhausted from the exhaust port 8.
[0011]
The heat shield cylinder 23 is mounted on the convex part 24 formed on the quartz rod 9 so as to cover the connection part 3. At this time, it is desirable to provide a flat part on the upper part of the convex part 24 and install it so that shrink fitting does not occur between the heat shield cylinder 23 and the convex part 24. The heat shield cylinder 23 needs to be large enough to shield the radiant heat from the lower side and the side by the high temperature body such as the heater 6 and the heat insulating material disposed around the heater 6 and received by the connecting portion 3.
[0012]
In the embodiment shown in FIG. 2, a heat shield plate 25 is provided on a convex portion 24 formed on the quartz rod 9, and a heat shield cylinder 23 is provided thereon. Most of heat from below is shielded. Since it is blocked by the hot plate 25, the heat shielding performance for the connecting portion 3 is further improved, and the thermal load on the connecting portion is reduced. In this case, the heat shield cylinder itself need not be provided with means for shielding the radiant heat from below. The combined use of the heat shield cylinder 23 and the heat shield plate 25 is more effective than the embodiment using only the heat shield cylinder 23 shown in FIG.
[0013]
FIG. 3 shows an example of the structure of the heat shield cylinder 23 of the present invention.
After connecting the quartz rod on the upper part of the porous glass base material and the shaft, a three-surface heat shielding component 26 is mounted on the convex portion provided on the quartz rod in the vicinity of the connecting portion so as to cover the connecting portion. The surface heat shield component 27 is attached so as to be hooked. A radiant heat leakage prevention plate 28 is provided on the one surface heat shield component 27 so that the radiant heat does not reach the vicinity of the connecting portion through the gap between the three surface heat shield component 26 and the one surface heat shield component 27. The upper part of the heat shield cylinder 23 is opened and has a structure in which heat is not accumulated inside.
[0014]
Since the heat shield cylinder and the heat shield plate are required to have a radiant heat shielding ability, a material having heat resistance, thermal shock resistance, and chlorine resistance is used. Si 3 N 4 can be cited as a material that satisfies these requirements, but Si 3 N 4 is a relatively expensive material. As an alternative to this, opaque quartz glass or a cheaper one on the quartz glass surface can be used. Those subjected to sandblast treatment can also be used.
The heat shield cylinder is installed as a connection portion heat shield member, and the shape may be any of a cylindrical shape, an elliptical column shape, and a prismatic shape as long as the shape surrounds the periphery of the connection portion. Moreover, although the bottom part of a heat insulation cylinder is bottomed , when installing on a heat insulation board, a bottomless thing may be sufficient.
[0015]
【Example】
Examples of the present invention and comparative examples are shown below, but the present invention is not limited to these, and various modes are possible.
Example 1
A porous glass base material having a diameter of 350 mmφ, a length of 1,900 mm, and a distance from the lower end of the connecting portion to the shaft to the upper end of the straight body synthesized by the OVD method is 500 mm. The wedge method shown in FIG. 2. A device having a heating means having a heater length of 400 mm shown in FIG. 2, in which a quartz rod on the upper part of a porous glass base material is connected to a shaft provided rotatably and a heat shield plate and a heat shield cylinder are mounted. Was used for transparent vitrification. In this way, 20 porous glass base materials were sintered and vitrified so that the upper end of the straight body of the porous glass base material came to a position 200 mm below the upper end of the heater. The shaft tube, pin, and wedge were not damaged.
[0016]
(Comparative Example 1)
A porous glass base material having a diameter of 350 mmφ, a length of 1,900 mm, and a distance of 500 mm from the lower end of the connecting portion to the upper end of the straight barrel synthesized by the OVD method is used as a heating means having a heater length of 400 mm shown in FIG. Without using a heat shield plate and heat shield cylinder, connect the quartz rod on the top of the porous glass base and the shaft using the wedge method shown in FIG. went. At this time, when the upper end of the straight body of the porous glass base material reached a position 150 mm below the upper end of the heater, shrink fitting occurred, and the shaft tube was cracked.
[0017]
【The invention's effect】
According to the present invention, a bottomed heat shield cylinder is provided in the vicinity of the connection portion so as to cover the connection portion between the porous glass base material and the shaft, or a heat shield cylinder is provided on the heat shield plate. Thus, the radiant heat received from the heater, the heat insulating material, etc. is reduced, the temperature rise of the connecting portion is suppressed, and shrink fitting is prevented. Thereby, the distance from a connection part to a base material effective part upper end can be made shorter than before. Accordingly, the effective length of the porous glass base material can be increased, the ratio of the tapered portion to be discarded is relatively reduced, the yield is improved, and the productivity is improved.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a glass base material manufacturing apparatus according to the present invention.
FIG. 2 is a schematic longitudinal sectional view showing a glass base material manufacturing apparatus different from FIG.
FIG. 3 is a schematic perspective view showing an example of the structure of the heat shield cylinder of the present invention.
FIG. 4 is a schematic longitudinal sectional view for explaining a transparent vitrification treatment of a porous glass base material.
FIG. 5 is a partial schematic longitudinal sectional view showing a connection example between a porous glass base material and a shaft.
FIG. 6 is a partial schematic longitudinal sectional view showing an example of connection between a porous glass base material and a shaft.
FIGS. 7A and 7B are schematic longitudinal sectional views for explaining the ratio of the effective portion of the porous glass base material. FIGS.
[Explanation of symbols]
1. 1. Porous glass base material Shaft 3. Connection unit 4. 4. Furnace core tube Rotating motor6. 6. Heater 7. Gas inlet 8. Exhaust port Quartz rod 10. 10. Wedge part Shaft tube 12. Hole 13. Pin 14. Convex part 15. Fitting member 16. Fitting part 17. Arrow 18. Distance between chucks 19. Effective part 20. Distance 21. Burner for depositing glass particles 22. Tapered portion 23. Heat shield cylinder 24. Convex part 25. Heat shield 26. Three-sided heat shielding component 27. One side heat shield component 28. Radiation heat leakage prevention plate

Claims (12)

反応容器内に吊り下げられた多孔質ガラス母材を加熱処理し、透明ガラス化を行う装置において、多孔質ガラス母材を吊り下げるシャフトと、多孔質ガラス母材上部の石英ロッドとの接続部が加熱手段および周囲の高温体から受ける輻射熱量を低減するために、該接続部近傍に設けられた有底筒状の接続部遮熱部材であることを特徴とする遮熱筒。  In a device that heat-treats the porous glass base material suspended in the reaction vessel and transforms it into a transparent glass, a connection part between the shaft for suspending the porous glass base material and the quartz rod above the porous glass base material In order to reduce the amount of radiant heat received from the heating means and the surrounding high-temperature body, the heat shield cylinder is a bottomed tubular connection portion heat shield member provided in the vicinity of the connection portion. 反応容器内に吊り下げられた多孔質ガラス母材を加熱処理し、透明ガラス化を行う装置において、多孔質ガラス母材を吊り下げるシャフトと、多孔質ガラス母材上部の石英ロッドとの接続部が加熱手段および周囲の高温体から受ける輻射熱量を低減するために、該接続部近傍に設けられた筒状の接続部遮熱部材であり、該接続部遮熱部材が下部からの輻射熱を防ぐための遮熱板上に設けられていることを特徴とする遮熱筒。  In a device that heat-treats the porous glass base material suspended in the reaction vessel and transforms it into a transparent glass, a connection part between the shaft for suspending the porous glass base material and the quartz rod above the porous glass base material In order to reduce the amount of radiant heat received from the heating means and the surrounding high-temperature body, it is a cylindrical connection portion heat shield member provided in the vicinity of the connection portion, and the connection portion heat shield member prevents radiant heat from below. A heat shield cylinder provided on the heat shield plate for the heat shield. 前記遮熱筒が、接続部近傍の周囲を取り囲むように設けられている請求項１又は２に記載の遮熱筒。  The heat shield tube according to claim 1 or 2, wherein the heat shield tube is provided so as to surround a periphery in the vicinity of the connecting portion. 前記遮熱筒の材質が、耐熱性、耐塩素性を有する請求項１乃至３のいずれかに記載の遮熱筒。  The heat shield tube according to any one of claims 1 to 3, wherein a material of the heat shield tube has heat resistance and chlorine resistance. 前記遮熱筒の材質が、表面をサンドブラスト処理された石英ガラスである請求項１乃至３のいずれかに記載の遮熱筒。  The heat shield tube according to any one of claims 1 to 3, wherein a material of the heat shield tube is quartz glass whose surface is sandblasted. 前記遮熱筒の材質が、不透明石英ガラスである請求項１乃至３のいずれかに記載の遮熱筒。  The heat shield tube according to any one of claims 1 to 3, wherein a material of the heat shield tube is opaque quartz glass. 前記遮熱筒の材質が、Ｓｉ3Ｎ4である請求項１乃至３のいずれかに記載の遮熱筒。The heat shield tube according to any one of claims 1 to 3 , wherein a material of the heat shield tube is Si 3 N 4 . 反応容器内に吊り下げられた多孔質ガラス母材を加熱処理し、透明ガラス化を行う装置であって、多孔質ガラス母材を吊り下げるシャフトと多孔質ガラス母材上部の石英ロッドとの接続部が加熱手段および周囲の高温体から受ける輻射熱量を低減するために、該接続部近傍に有底筒状の遮熱筒が設けられていることを特徴とするガラス母材の製造装置。  A device that heat-treats the porous glass base material suspended in the reaction vessel and transforms it into a transparent glass, and connects the shaft that suspends the porous glass base material and the quartz rod above the porous glass base material. In order to reduce the amount of radiant heat received from the heating means and the surrounding high-temperature body, a glass base material manufacturing apparatus characterized in that a bottomed cylindrical heat shield cylinder is provided in the vicinity of the connecting portion. 反応容器内に吊り下げられた多孔質ガラス母材を加熱処理し、透明ガラス化を行う装置であって、多孔質ガラス母材を吊り下げるシャフトと多孔質ガラス母材上部の石英ロッドとの接続部が加熱手段および周囲の高温体から受ける輻射熱量を低減するために、該接続部近傍に遮熱筒が下部からの輻射熱を防ぐための遮熱板上に設けられていることを特徴とするガラス母材の製造装置。  A device that heat-treats the porous glass base material suspended in the reaction vessel and transforms it into a transparent glass, and connects the shaft that suspends the porous glass base material and the quartz rod above the porous glass base material. In order to reduce the amount of radiant heat received from the heating means and the surrounding high-temperature body, the heat shield tube is provided on the heat shield plate for preventing radiant heat from the lower part in the vicinity of the connecting portion. Glass base material manufacturing equipment. 請求項４乃至７のいずれかに記載の材質からなる遮熱筒が、接続部近傍に設けられている請求項８又は９に記載のガラス母材の製造装置。  The manufacturing apparatus of the glass base material of Claim 8 or 9 with which the heat shield cylinder which consists of a material in any one of Claim 4 thru | or 7 is provided in the connection part vicinity. 前記遮熱筒が、接続部近傍の周囲を取り囲むように設けられている請求項８又は９に記載のガラス母材の製造装置。  The manufacturing apparatus of the glass base material of Claim 8 or 9 with which the said heat insulation cylinder is provided so that the circumference | surroundings of the connection part vicinity may be enclosed. 請求項８乃至１１のいずれかに記載のガラス母材の製造装置を用いて製造することを特徴とするガラス母材の製造方法。  It manufactures using the manufacturing apparatus of the glass base material in any one of Claims 8 thru | or 11, The manufacturing method of the glass base material characterized by the above-mentioned.
JP2000234678A 2000-08-02 2000-08-02 Heat shield cylinder, glass base material manufacturing apparatus and method including the same Expired - Fee Related JP4435390B2 (en)

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JP5854964B2 (en) * 2012-10-05 2016-02-09 信越化学工業株式会社 Glass base material suspension mechanism
JP6184360B2 (en) * 2014-03-26 2017-08-23 信越化学工業株式会社 Sintering equipment for glass preform for optical fiber
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