JP2003048722A - Method for manufacturing porous glass preform - Google Patents

Method for manufacturing porous glass preform

Info

Publication number
JP2003048722A
JP2003048722A JP2001237797A JP2001237797A JP2003048722A JP 2003048722 A JP2003048722 A JP 2003048722A JP 2001237797 A JP2001237797 A JP 2001237797A JP 2001237797 A JP2001237797 A JP 2001237797A JP 2003048722 A JP2003048722 A JP 2003048722A
Authority
JP
Japan
Prior art keywords
burner
glass
flame
porous glass
distance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
JP2001237797A
Other languages
Japanese (ja)
Inventor
Toshihiro Oishi
敏弘 大石
Motonori Nakamura
元宣 中村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP2001237797A priority Critical patent/JP2003048722A/en
Publication of JP2003048722A publication Critical patent/JP2003048722A/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—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]
    • C03B37/01413—Reactant delivery systems
    • C03B37/0142—Reactant deposition burners
    • 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
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/50—Multiple burner arrangements
    • C03B2207/52—Linear array of like burners
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/60—Relationship between burner and deposit, e.g. position
    • C03B2207/66—Relative motion
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/70—Control measures

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Glass Melting And Manufacturing (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a porous glass preform which is capable of effectively eliminating the fluctuation (the fluctuation in the exter nal diameter) of the amount of glass particulate deposition in a turn-back posi tion of reciprocation motion and is low in the ratio of forming the non-effective section of an end in a high-speed multilayer deposition method of using a plural ity of burners and successively depositing the glass particulate synthesized by the burners on the surface of a starting rood while relatively moving the rotating starting rod and the burners back and forth. SOLUTION: The method of manufacturing the porous glass preform comprises performing the high-speed multilayer deposition method by a system of turning back the reciprocating motion after moving the burners by a distance ±B around a reference point and setting the distance B at <1/2 the spacing L between the burners and changing the distance according to the growth of a glass particulate deposit.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、出発ロッドとガラ
ス微粒子合成用バーナとを相対的に往復運動させなが
ら、ロッド上に径方向にガラス微粒子を堆積させる多孔
質ガラス母材の製造方法に関し、特に外径変動が少なく
両端に形成されるテーパ部が少ない多孔質ガラス母材が
得られる多孔質ガラス母材の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous glass base material in which glass particles are deposited in a radial direction on a rod while reciprocating a starting rod and a burner for synthesizing glass particles relatively. In particular, the present invention relates to a method for producing a porous glass base material that can obtain a porous glass base material that has a small outer diameter variation and a small number of tapered portions formed on both ends.

【０００２】[0002]

【従来の技術】大型の多孔質ガラス母材を高速で製造す
る方法として、反応容器内の出発ロッドに対向させて複
数のガラス微粒子合成用バーナを一定間隔で配置し、回
転する出発ロッドと前記バーナの列を相対的に往復移動
させ、出発ロッドの表面にガラス微粒子を層状に堆積さ
せてガラス微粒子堆積体を得る方法（多層付け法）があ
る。2. Description of the Related Art As a method for producing a large-sized porous glass preform at a high speed, a plurality of burners for synthesizing glass particles are arranged at regular intervals so as to face a starting rod in a reaction vessel, and a rotating starting rod and There is a method (multilayering method) in which a row of burners is relatively reciprocally moved and glass particles are deposited in layers on the surface of a starting rod to obtain a glass particle deposit.

【０００３】以下、説明の簡略化のため出発ロッドを固
定し、バーナを往復運動させる形式を主体に説明する。
前記のような方法において、複数本のバーナを均等間隔
に配置、固定したバーナアレイをバーナ間隔分だけ往復
運動させると、各バーナがバーナ間隔分の区間にガラス
微粒子を堆積させていくことになり、これらの区間が合
体して大型の多孔質ガラス母材が形成される。各バーナ
についてバーナの折り返し位置は、隣接するバーナがガ
ラス微粒子を堆積している区間との境目となる。この折
り返し位置では、バーナが定速で移動しながらガラス微
粒子を堆積している区間とは異なる要因が多く存在す
る。For the sake of simplification of the description, a method of fixing the starting rod and reciprocating the burner will be mainly described below.
In the above method, a plurality of burners are arranged at equal intervals, and when the fixed burner array is reciprocated by the burner interval, each burner will deposit glass particles in the interval corresponding to the burner interval. These sections are united to form a large-sized porous glass preform. The folding position of the burner for each burner is a boundary with the section where the adjacent burner deposits glass particles. At this folding position, there are many factors different from the section where the burner moves at a constant speed and the glass particles are deposited.

【０００４】多孔質ガラス母材の外径変動に与える影響
が最も大きい要因は、ガラス微粒子はバーナに相対する
点で堆積していくわけではなく、バーナ火炎の広がりに
依存した広さをもって堆積していくため、バーナの折り
返し位置では隣接したバーナにより堆積したガラス微粒
子も存在し、二重塗りのような状態となっていることで
ある。他の要因としては、折り返しをするためにはバー
ナアレイの駆動が一旦停止するため、折り返し位置では
定速で移動している部分よりも長時間バーナが存在する
ことになり、ガラス微粒子の堆積量が増えることであ
る。The most significant factor affecting the variation of the outer diameter of the porous glass base material is that the glass particles are not deposited at the points facing the burner, but are deposited with an area depending on the spread of the burner flame. Therefore, at the turning position of the burner, the glass particles deposited by the adjacent burner are also present, and the state is like double coating. Another factor is that the drive of the burner array is temporarily stopped in order to make a turnaround, so that the burner exists at the turnaround position for a longer period of time than at the part that is moving at a constant speed, and the deposition amount of glass particles is reduced. It is to increase.

【０００５】これらの問題を解消するため、折り返しの
位置においてバーナへの原料の供給量を調整しようとす
ると原料と酸水素火炎の割合が大きく変化し、このため
ガラス微粒子堆積面の温度が変化してしまい（原料を大
幅に減らすと堆積面温度は著しく高くなる）、ガラス密
度の変動を招く。ガラス密度が変わるとガラス層の厚み
が変化することから外径変動につながることとなる。こ
のような複合要因により、折り返し位置ではガラス微粒
子の堆積量の変化が発生している。In order to solve these problems, if the feed amount of the raw material to the burner is adjusted at the turnaround position, the ratio of the raw material and the oxyhydrogen flame greatly changes, which changes the temperature of the glass particulate deposition surface. (The temperature of the deposition surface becomes extremely high when the raw material is drastically reduced), which causes the fluctuation of the glass density. When the glass density changes, the thickness of the glass layer changes, which leads to a change in outer diameter. Due to such complex factors, the amount of glass particles deposited changes at the folding position.

【０００６】前記の複数本のバーナを使用した高速多層
付け方法の従来技術として特開平３−２２８８４５号公
報あるいは特開平４−２６０６１８号公報などがある。
これらの公報に提案された技術においては、前記のよう
なバーナの折り返し位置の問題を解消するため、往復運
動における往路と復路の移動距離を異ならせることによ
り折り返し位置を移動させている。すなわち、バーナと
出発ロッドの相対往復運動の折り返し位置による影響を
多孔質ガラス母材全長に分散させることによって、堆積
量を平均化させ多孔質ガラス母材の外径均一化を行って
いる。As a conventional technique for a high-speed multi-layering method using a plurality of burners described above, there are JP-A-3-228845 and JP-A-4-260618.
In the techniques proposed in these publications, in order to solve the problem of the turning position of the burner as described above, the turning position is moved by making the moving distance of the forward path and the returning path in the reciprocating motion different. That is, the influence of the turn-back position of the relative reciprocating motion of the burner and the starting rod is dispersed over the entire length of the porous glass base material to average the deposition amount and make the outer diameter of the porous glass base material uniform.

【０００７】例えば前記特開平３−２２８８４５号公報
の方法では、往復運動の往路の距離を一定とし、復路の
距離を（往路の距離±α）に変化させることで折り返し
位置の移動を行っている。すなわち、復路の距離を（往
路の距離−α）として往復を行わせると、折り返し位置
が一方向にαずつ移動していく。折り返し位置がバーナ
の間隔分移動したところで復路の距離を（往路の距離＋
α）に変更すると、今度は折り返し位置が逆方向にαず
つ移動していき、最初の折り返し位置に戻る。各バーナ
の折り返し位置の出現パターンに着目すれば、折り返し
位置がαの間隔で母材全長に分散された形になっている
ことがわかる。For example, in the method disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-228845, the turn-back position is moved by keeping the forward path distance of the reciprocating motion constant and changing the backward path distance (outward path distance ± α). . That is, when the vehicle is reciprocated with the distance of the return path being (the distance of the outward path-α), the turn-back position moves by α in one direction. When the turn-back position has moved by the burner interval, the return path distance (outward path distance +
If it is changed to α), the turnaround position moves in the opposite direction by α, and returns to the first turnaround position. Focusing on the appearance pattern of the turning position of each burner, it is found that the turning positions are distributed over the entire length of the base material at intervals of α.

【０００８】[0008]

【発明が解決しようとする課題】前記従来技術は、有効
部の外径変動を少なくするという面では効果が大きいも
のである。しかし往復運動の折り返し位置を例えばバー
ナ間隔分だけ移動させるので、多孔質ガラス母材の両端
部ではガラス微粒子の堆積量が少なくなり、移動させた
分だけ多孔質ガラス母材の両端に形成される非有効部の
長さが長くなるという問題がある。本発明はこのような
従来技術の実状に鑑み、複数本のバーナを使用した高速
多層付け方法において、往復運動の折り返し位置に相当
する部分でのガラス微粒子堆積量の変動（外径変動）を
効果的に解消でき、しかも端部の非有効部の形成割合が
少ない多孔質ガラス母材の製造方法を提供することを目
的とする。The prior art described above is very effective in reducing the fluctuation of the outer diameter of the effective portion. However, since the turn-back position of the reciprocating movement is moved by, for example, the burner interval, the amount of fine glass particles deposited on both ends of the porous glass base material is small, and the amount of movement is formed on both ends of the porous glass base material. There is a problem that the length of the ineffective portion becomes long. In view of such a state of the art as described above, the present invention has an effect on the fluctuation (outer diameter fluctuation) of the glass particulate deposition amount in the portion corresponding to the turning position of the reciprocating motion in the high-speed multi-layering method using a plurality of burners. It is an object of the present invention to provide a method for producing a porous glass base material which can be eliminated in a simple manner and in which the ratio of formation of ineffective portions at the ends is small.

【０００９】[0009]

【課題を解決するための手段】本発明は上記課題を解決
する手段として、次の（１）〜（７）に示す構成を採る
ものである。 （１）回転する出発ロッドに対向させて複数本のガラス
微粒子合成用バーナを配置し、前記出発ロッドとガラス
微粒子合成用バーナとを平行に相対的に往復運動させな
がらバーナで合成されるガラス微粒子を出発ロッドの表
面に順次堆積させて多孔質ガラス母材を製造する方法に
おいて、往復運動を基準点を中心に一方向に距離Ｂだけ
移動して折り返し、反対方向へ基準点から距離Ｂだけ移
動して折り返す方式で行い、距離Ｂをバーナ間隔Ｌの１
／２未満とし、かつ、ガラス微粒子堆積体の成長に応じ
て変化させることを特徴とする多孔質ガラス母材の製造
方法。 （２）前記距離Ｂをガラス微粒子堆積面における火炎の
広がりを基準にして変化させることを特徴とする前記
（１）の多孔質ガラス母材の製造方法。The present invention adopts the following constitutions (1) to (7) as means for solving the above problems. (1) A plurality of glass fine particle synthesizing burners are arranged facing a rotating starting rod, and the fine glass particles are synthesized by the burner while relatively reciprocating the starting rod and the glass fine particle synthesizing burner in parallel. In the method of manufacturing a porous glass preform by sequentially depositing on the surface of the starting rod, the reciprocating motion is moved by a distance B in one direction around the reference point and folded back, and moved in the opposite direction by a distance B from the reference point. Then, the distance B is set to 1 of the burner interval L.
A method for producing a porous glass preform, which is less than / 2 and is changed according to the growth of the glass fine particle deposit. (2) The method for producing a porous glass preform according to (1) above, wherein the distance B is changed with reference to the spread of the flame on the glass particulate deposition surface.

【００１０】（３）火炎の広がりが、バーナ火炎の輝度
分布、ＣＣＤカメラ等による画像処理、及び温度測定装
置により測定される温度分布のうちの１つ以上の手段に
より測定される値により定義されることを特徴とする前
記（２）の多孔質ガラス母材の製造方法。 （４）前記ＢがＢ＝（Ｌ−Ｘ）／２〔ただし、Ｌ：バー
ナ間隔、Ｘ：ガラス微粒子堆積面における１つのバーナ
の火炎による堆積面の温度が所定温度以上となる範囲の
長さ〕で定義される値であることを特徴とする前記
（３）の多孔質ガラス母材の製造方法。 （５）前記往復運動の移動速度を５〜６００ｍｍ／分と
することを特徴とする前記（１）〜（４）のいずれか１
項に記載の多孔質ガラス母材の製造方法。 （６）往復運動の折り返し位置において、ガラス微粒子
合成用バーナによるガラス微粒子の発生量を調整するこ
とを特徴とする前記（１）〜（５）のいずれか１つの多
孔質ガラス母材の製造方法。 （７）前記ガラス微粒子発生量の調整を、ガラス原料供
給量を調整することによって行い、かつ、往復運動定常
部におけるバーナの火炎温度に対する火炎温度の変化が
±１５℃以内となる範囲で行うことを特徴とする前記
（６）の多孔質ガラス母材の製造方法。(3) The spread of the flame is defined by a value measured by one or more of a brightness distribution of the burner flame, image processing by a CCD camera, and a temperature distribution measured by a temperature measuring device. (2) The method for producing a porous glass preform according to (2) above. (4) B is B = (L−X) / 2 [where L: burner interval, X: length of a range in which the temperature of the deposition surface due to the flame of one burner on the glass particulate deposition surface is equal to or higher than a predetermined temperature] ] It is a value defined by these, The manufacturing method of the porous glass base material of said (3) characterized by the above-mentioned. (5) Any one of (1) to (4) above, wherein the reciprocating movement speed is 5 to 600 mm / min.
The method for producing a porous glass preform according to item. (6) The method for producing a porous glass preform according to any one of the above (1) to (5), wherein the amount of glass particles generated by the burner for synthesizing glass particles is adjusted at the turning back position of the reciprocating motion. . (7) The amount of glass particles generated is adjusted by adjusting the amount of glass raw material supplied, and within a range where the change in flame temperature with respect to the flame temperature of the burner in the reciprocating motion stationary part is within ± 15 ° C. (6) The method for producing a porous glass preform according to (6) above.

【００１１】[0011]

【発明の実施の形態】以下、本発明の方法について図面
を参照して説明する。図１は移動するバーナによるガラ
ス微粒子の堆積状態を模式的に示す説明図である。図１
において符号１は出発ロッド、２はバーナによる火炎、
３はガラス微粒子堆積層を示している。図１（ａ）は１
本のバーナ（第１バーナ４）が基準点（図中に一点破線
で示す）を中心に両側にバーナ間隔（２ａ）の１／２ず
つ往復（一方向への移動距離はバーナ間隔分となる）す
る間に堆積するガラス微粒子堆積層３の形態を示してい
る。DETAILED DESCRIPTION OF THE INVENTION The method of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view schematically showing a deposition state of glass particles by a moving burner. Figure 1
In FIG. 1, reference numeral 1 is a starting rod, 2 is a burner flame,
Reference numeral 3 indicates a glass particle deposition layer. 1 in FIG.
The book burner (first burner 4) reciprocates by ½ of the burner interval (2a) on both sides around the reference point (indicated by the dashed line in the figure) (the moving distance in one direction is the burner interval). 2 shows the morphology of the glass particle deposition layer 3 deposited during the process.

【００１２】バーナ本数が２本（第１バーナ４と第２バ
ーナ５）になると、図１（ｂ）に示すようにバーナ間隔
分移動させると折り返し位置で二重堆積状態が生じ、堆
積量が増加し、外径変動の原因となる。なお、説明の簡
略化のため図には記載していないが、折り返し点近傍で
は後述するようにバーナの移動停止による堆積量の増加
もあり、移動速度によってはその影響も考慮する必要が
ある。隣接バーナによる堆積量増加を抑制するために
は、図１（ｃ）に示すように往復運動の距離をバーナ間
隔よりも若干短い２ｂ（ａ＞ｂ）とし、重複堆積量を少
なくすることによって、折り返し位置での堆積量の均等
化が可能である。When the number of burners becomes two (the first burner 4 and the second burner 5), when the burner is moved by the burner interval as shown in FIG. Increase and cause variation in outer diameter. Although not shown in the figure for simplification of the description, there is an increase in the amount of deposition due to the stop of the burner movement in the vicinity of the turning point, as will be described later, and it is necessary to consider the effect depending on the movement speed. In order to suppress the increase in the deposition amount due to the adjacent burners, the reciprocating motion distance is set to 2b (a> b), which is slightly shorter than the burner interval, as shown in FIG. It is possible to equalize the amount of deposition at the folding position.

【００１３】しかしながら、堆積量の均等化のためには
ガラス微粒子堆積体の成長により、堆積面における火炎
の広がり（ガラス微粒子の堆積が生じる温度以上となる
範囲）が変化してくることを考慮する必要がある。すな
わち、図２に示すようにガラス微粒子堆積体が成長する
と堆積面における火炎の広がりはｘ1 からｘ2 に増大す
る。その結果図３に示すように、往復運動の距離をバー
ナ間隔よりも若干短い２ｂとしておいても、火炎の広が
りによる重複堆積量の増加により外径変動を生じるよう
になる。ガラス微粒子の堆積形態を注意深く調査した結
果、ガラス微粒子の堆積量はバーナの中心が最も多く、
火炎の最外部へ向かって減少していく。このことから、
図４に示すように一つのバーナの火炎の端（バーナ火炎
によってガラス微粒子の堆積が生じる温度以上となる範
囲の端）が、隣接バーナの火炎の中心にくるようにする
のがよいことがわかる。However, in order to equalize the amount of deposition, it is considered that the spread of the flame on the deposition surface (the range above the temperature at which the deposition of glass particles occurs) changes due to the growth of the glass particle deposit body. There is a need. That is, as shown in FIG. 2, when the glass particulate deposit grows, the spread of the flame on the deposition surface increases from x 1 to x 2 . As a result, as shown in FIG. 3, even if the distance of the reciprocating motion is set to 2b, which is slightly shorter than the burner interval, the outer diameter changes due to the increase in the overlapping deposition amount due to the spread of the flame. As a result of careful investigation of the deposition form of glass particles, the deposition amount of glass particles was highest in the center of the burner,
It decreases toward the outermost part of the flame. From this,
As shown in FIG. 4, it can be seen that the end of the flame of one burner (the end of the range above the temperature at which glass particulates are deposited by the burner flame) is located at the center of the flame of the adjacent burner. .

【００１４】これらの知見から、本発明においては堆積
面の温度を測定しながら、図４の状態を常に維持できる
ように往復運動の移動距離を調整するようにした。すな
わち、図５に示すように基準点を中心に±βの距離の移
動を行わせるようにし（プラス側に距離β移動させて折
り返して基準点に戻り、マイナス側に距離β移動させて
折り返して基準点に戻るまでを往復運動１回とする）、
数回〜数十回の往復運動ごとに移動距離の修正を行い、
図４の形に近づくようにβの値を小さくすることとし
た。具体的には修正の都度、βがＢ＝（Ｌ−Ｘ）／２
〔ただし、Ｌ：バーナ間隔、Ｘ：ガラス微粒子堆積面に
おける１つのバーナの火炎による堆積面の温度が所定温
度以上となる範囲の長さ〕で定義されるＢの値になるよ
うにし、少なくともＢ±１０ｍｍの範囲とするのが好ま
しい。なお、上記の所定温度以上とは、ガラス微粒子の
堆積が生じる温度以上を意味する。ガラス微粒子堆積面
の温度は、バーナ火炎の輝度分布、ＣＣＤカメラ等の光
学機器による画像処理、及び温度測定装置などにより測
定することができる。From these findings, in the present invention, the moving distance of the reciprocating motion is adjusted so that the state of FIG. 4 can always be maintained while measuring the temperature of the deposition surface. That is, as shown in FIG. 5, a distance of ± β is moved around the reference point (the distance β is moved to the plus side and folded back to the reference point, and the distance β is moved to the minus side and folded back. One reciprocating motion is required to return to the reference point),
The travel distance is corrected for each reciprocating motion of several times to several tens of times.
It was decided to reduce the value of β so as to approach the shape of FIG. Specifically, β is B = (L−X) / 2 each time it is corrected.
[Where L is the burner interval, X is the length of the range where the temperature of the deposition surface due to the flame of one burner on the glass particulate deposition surface is equal to or higher than a predetermined temperature], and the value of B is at least B The range is preferably ± 10 mm. The above-mentioned predetermined temperature or higher means a temperature higher than the temperature at which the deposition of glass particles occurs. The temperature of the glass particle deposition surface can be measured by the brightness distribution of the burner flame, image processing by an optical device such as a CCD camera, and a temperature measuring device.

【００１５】前記のように往復運動の折り返し位置にお
いては、隣接バーナによる重複堆積の他に折り返し時の
バーナの一時的停止による堆積量の増加という問題があ
る。本発明のような複数本のバーナを使用した高速多層
付け方法においては、通常、バーナの移動速度は７００
〜１０００ｍｍ／分程度である。折り返し位置における
バーナの停止の影響は定速移動時のバーナの移動速度が
速いほど大きくなる。そのためバーナの停止による影響
が大きい場合には定速移動時のバーナの移動速度を５０
〜６００ｍｍ／分程度に低下させるのが望ましい。機械
的な停止時間はバーナの移動速度が変わっても大きく変
わることはないので、移動速度を遅くすることで定速移
動部との堆積時間の差を減少させることができる。As described above, at the turn-back position of the reciprocating motion, there is a problem that the deposition amount increases due to the temporary stop of the burner at the time of turn-back, in addition to the overlapping deposition by the adjacent burners. In a high-speed multi-layering method using a plurality of burners as in the present invention, the burner moving speed is usually 700.
It is about 1000 mm / min. The influence of the stop of the burner at the folding position becomes greater as the moving speed of the burner during constant speed movement becomes faster. Therefore, if the effect of stopping the burner is great, set the moving speed of the burner to 50 when moving at a constant speed.
It is desirable to reduce the pressure to about 600 mm / min. Since the mechanical stop time does not change significantly even if the moving speed of the burner changes, it is possible to reduce the difference in the deposition time from the constant speed moving section by slowing the moving speed.

【００１６】バーナの特性等により、移動速度を遅くす
るだけでは折り返し位置でのバーナ停止時の堆積量と定
速移動中の堆積量との差を吸収しきれず問題となる場合
には、さらにガラス微粒子の堆積面温度が変化しない程
度でガラス原料等の供給量を調整することでガラス微粒
子生成量を微調整し、折り返し位置での堆積量の調整を
行うのが好ましい。具体的な調整方法は特に限定される
ものではないが、例えば定速移動部の原料流量をＭ、実
測折り返し時間をＴ、計算折り返し時間をＴ0としたと
きに、停止時のバーナの原料流量Ｍ′がＭ′＝Ｍ×〔１
−（Ｔ−Ｔ0 ）／Ｔ0 〕となるように調整すればよい。If the difference between the amount of deposits when the burner is stopped at the turn-back position and the amount of deposits during constant speed movement cannot be fully absorbed due to the characteristics of the burner and the like, and only a problem is caused, a glass is further added. It is preferable to finely adjust the amount of glass fine particles produced by adjusting the supply amount of the glass raw material or the like to the extent that the temperature of the deposition surface of the fine particles does not change, and to adjust the amount of deposition at the folding position. Although the specific adjustment method is not particularly limited, for example, when the flow rate of the raw material in the constant velocity moving part is M, the measured turnaround time is T, and the calculated turnaround time is T 0 , the raw material flow rate of the burner at the time of stop is M ′ is M ′ = M × [1
It may be adjusted such that − (T−T 0 ) / T 0 ].

【００１７】ここで、計算折り返し時間とは停止時間な
しで折り返しを行うと仮定したときの往復運動時間であ
り、実測折り返し時間とは折り返しの停止時間を含んだ
往復運動時間である。さらに詳述すれば基準点からスタ
ートし、相対運動の折り返しが１回行われ基準点に戻っ
てくるまでの所要時間が実測折り返し時間であり、設定
速度で同距離動くのに要する時間を求めたのが計算折り
返し時間である。また、この流量調整は折り返し位置に
おいて瞬時的に変更するのではなく、バーナの加減速を
考慮し、Ｍから徐々に（例えば直線的に）Ｍ′に近づけ
ていき、折り返しの瞬間にはＭ′となるように調整する
のが望ましい。なお、条件によっては移動速度の調整は
行わず原料の流量調整のみで、折り返し位置におけるガ
ラス微粒子堆積量の調整を行うこともできる。Here, the calculated turnaround time is the reciprocating time when it is assumed that the turnaround is performed without the stop time, and the actually measured turnaround time is the reciprocating time including the stop time of the turnaround. More specifically, the time required to start from the reference point and return to the reference point after one turn of relative movement is performed is the actually measured turnaround time, and the time required to move the same distance at the set speed was obtained. Is the calculated turnaround time. Further, this flow rate adjustment does not change instantaneously at the turn-back position, but gradually increases (for example, linearly) from M to M'in consideration of burner acceleration and deceleration, and at the moment of turn-back, M ' It is desirable to adjust so that Depending on the conditions, it is possible to adjust the glass particulate deposition amount at the folding position by only adjusting the flow rate of the raw material without adjusting the moving speed.

【００１８】ガラス原料の供給量の調整によるガラス微
粒子生成量の調整を行う場合には、往復運動定常部にお
けるバーナの火炎温度に対する火炎温度の変化が±１５
℃以内となる範囲で行うことが望ましい。温度変化がこ
の範囲を超えると嵩密度の変化が大きくなり、これが新
たな外径変動の要因となるおそれがあるためである。When the production amount of glass particles is adjusted by adjusting the supply amount of the glass raw material, the change in flame temperature with respect to the flame temperature of the burner in the steady part of the reciprocating motion is ± 15.
It is desirable to perform it within the range of ℃. This is because if the temperature change exceeds this range, the change in bulk density becomes large, which may cause a new variation in outer diameter.

【００１９】[0019]

【実施例】以下、実施例により本発明の方法をさらに具
体的に説明するが、本発明はこれに限定されるものでは
ない。 （実施例１）出発ロッド（直径３６ｍｍ、長さ１３００
ｍｍ）に対向させて４本のバーナを２００ｍｍ間隔で配
置し、出発ロッドを軸回りに回転させながら往復運動さ
せる方式でガラス微粒子の堆積を行った。出発ロッドの
移動速度は５０ｍｍ／分とし、バーナ火炎の広がりが測
定できるようにサーモトレーサーを配置して感知温度を
３５０℃以上にセットし、バーナ火炎によりガラス微粒
子堆積面温度が４００℃以上となる部分の長さ（出発ロ
ッドの長さ方向の長さ）を火炎の広がりとして定義し
た。EXAMPLES The method of the present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. (Example 1) Starting rod (diameter 36 mm, length 1300)
mm) and four burners are arranged at intervals of 200 mm, and glass fine particles are deposited by a method of reciprocating while rotating the starting rod around the axis. The moving speed of the starting rod is 50 mm / min, the thermotracer is arranged so that the spread of the burner flame can be measured, and the sensing temperature is set to 350 ° C or higher, and the temperature of the glass particulate deposition surface becomes 400 ° C or higher due to the burner flame. The length of the part (length along the length of the starting rod) was defined as the spread of the flame.

【００２０】火炎の広がりはガラス微粒子堆積体の成長
により変化していくため、ここでは上記測定により得ら
れた火炎の広がりをＡｍｍとし、往復運動は基準点を中
心に±βｍｍ移動させることとし、βは所定の往復運動
回数ごとにＡを測定し、β＝（２００−Ａ）／２の式に
より移動距離を修正した。図６にガラス微粒子堆積体の
成長に伴ってＡが変化していく状態を模式的に示す。図
６はガラス微粒子堆積層３が左側の大きさ（堆積層の厚
みｙ1 ）であった時のバーナ６の火炎２の広がりがＡ1
であったのに対し、ガラス微粒子堆積層３が成長して右
側の大きさ（堆積層の厚みｙ2 ）となったときの火炎２
の広がりがＡ2 となったことを示している。なお、図６
には火炎の形状として、ガラス微粒子の堆積温度以下の
部分を含めた火炎全体の到達範囲を示しているが、この
うちの温度４００℃以上の範囲が上記の火炎の広がりＡ
に相当する。Since the spread of the flame changes with the growth of the glass particulate deposit, the spread of the flame obtained by the above measurement is Amm, and the reciprocating motion is to move ± βmm around the reference point. As for β, A was measured for each predetermined number of reciprocating movements, and the moving distance was corrected by the formula of β = (200−A) / 2. FIG. 6 schematically shows a state in which A changes with the growth of the glass particulate deposit. In FIG. 6, the spread of the flame 2 of the burner 6 is A 1 when the glass particle deposition layer 3 has a size on the left side (deposition layer thickness y 1 ).
On the other hand, the flame 2 when the glass particle deposition layer 3 grew to the size on the right side (deposition layer thickness y 2 ).
Indicates that the spread of A became A 2 . Note that FIG.
Shows the reach range of the entire flame including the portion below the deposition temperature of the glass particles as the shape of the flame. Of these, the range above 400 ° C. is the spread of the above flame A
Equivalent to.

【００２１】基準点からプラス側に移動し、折り返して
基準点に戻り、次にマイナス側に移動し、折り返して基
準点に戻る動きを往復運動１回と定義し、往復運動１０
回ごとにＡの値を見直して往復運動距離βの調整を行っ
た。この往復運動を１００回行い、外径が２５０±２ｍ
ｍの多孔質ガラス母材を得ることができた。このガラス
微粒子堆積工程中のＡ及びβの値の変化を表１に示す。
また、多孔質ガラス母材の両端に形成されたテーパ部の
長さはそれぞれ１２０ｍｍであった。多孔質ガラス母材
の長さは９００ｍｍであり、全長に占める非有効部（テ
ーパ部）の割合は２７％であった。The movement from the reference point to the plus side, the return to the reference point, the return to the minus side, the return to the reference point is defined as one reciprocating motion.
The value of A was reviewed every time and the reciprocating distance β was adjusted. This reciprocating motion is performed 100 times and the outer diameter is 250 ± 2 m.
m porous glass base material could be obtained. Table 1 shows the changes in the values of A and β during this glass particulate deposition process.
The length of the tapered portion formed on each end of the porous glass base material was 120 mm. The length of the porous glass base material was 900 mm, and the ratio of the ineffective portion (tapered portion) to the entire length was 27%.

【００２２】[0022]

【表１】 [Table 1]

【００２３】（比較例１）出発ロッド及びバーナの設定
は実施例１と同じとし、ガラス微粒子堆積体の成長に連
れての移動距離の調整は行わず、バーナの折り返し位置
を２０ｍｍずつ移動させていき、折り返し位置がバーナ
の間隔分（２００ｍｍ）移動したところで今度は反対側
に移動させる方式（特開平３−２２８８４５号公報の実
施例１に準じた方法）により多孔質ガラス母材を作製し
た。その結果、外径が２５０±２ｍｍの多孔質ガラス母
材を得ることができたが、両端のテーパ部の長さはそれ
ぞれ２８０ｍｍとなっていた。得られた多孔質ガラス母
材の長さは１１００ｍｍであり、全長に占める非有効部
の比率は５１％であった。(Comparative Example 1) The starting rod and burner were set the same as in Example 1, the moving distance was not adjusted as the glass particulate deposit grew, and the turning position of the burner was moved by 20 mm. A porous glass preform was prepared by a method of moving the folding position to the opposite side after moving by the burner interval (200 mm) (method according to Example 1 of JP-A-3-228845). As a result, it was possible to obtain a porous glass base material having an outer diameter of 250 ± 2 mm, but the lengths of the tapered portions at both ends were 280 mm, respectively. The length of the obtained porous glass base material was 1100 mm, and the ratio of the ineffective portion to the entire length was 51%.

【００２４】[0024]

【発明の効果】本発明によれば、複数本のバーナを使用
した高速多層付け方法において、往復運動の折り返し位
置に相当する部分でのガラス微粒子堆積量の変動（外径
変動）を効果的に解消でき、しかも端部の非有効部の形
成割合が少ない多孔質ガラス母材の製造方法が提供され
る。According to the present invention, in the high-speed multi-layering method using a plurality of burners, the fluctuation of the glass particulate deposition amount (outer diameter fluctuation) at the portion corresponding to the folding position of the reciprocating motion can be effectively performed. Provided is a method for producing a porous glass preform which can be eliminated and in which the ratio of formation of ineffective portions at the ends is small.

【図面の簡単な説明】[Brief description of drawings]

【図１】移動するバーナによるガラス微粒子の堆積状態
を模式的に示す説明図。FIG. 1 is an explanatory view schematically showing a deposition state of glass fine particles by a moving burner.

【図２】ガラス微粒子堆積体の成長により火炎の広がり
が変化する状態を示す説明図。FIG. 2 is an explanatory view showing a state in which the spread of the flame changes due to the growth of the glass particle deposit body.

【図３】隣接するバーナによる重複堆積の状態を示す説
明図。FIG. 3 is an explanatory view showing a state of overlapping deposition by adjacent burners.

【図４】隣接するバーナによる重複堆積を軽減した状態
を示す説明図。FIG. 4 is an explanatory view showing a state in which overlapping deposition by adjacent burners is reduced.

【図５】本発明における移動距離を決める基本的な考え
方を説明する図。FIG. 5 is a diagram for explaining a basic concept for determining a moving distance in the present invention.

【図６】実施例における移動距離修正の基になる火炎の
広がりの変化を示す説明図。FIG. 6 is an explanatory diagram showing a change in the spread of the flame which is a basis for correction of the moving distance in the embodiment.

【符号の説明】[Explanation of symbols]

１ 出発ロッド ２ 火炎 ３ ガラス微粒子堆積層
４ 第１バーナ ５ 第２バーナ ６ バーナ1 Starting Rod 2 Flame 3 Glass Particle Deposit Layer 4 First Burner 5 Second Burner 6 Burner

Claims (7)

【特許請求の範囲】[Claims] 【請求項１】 回転する出発ロッドに対向させて複数本
のガラス微粒子合成用バーナを配置し、前記出発ロッド
とガラス微粒子合成用バーナとを平行に相対的に往復運
動させながらバーナで合成されるガラス微粒子を出発ロ
ッドの表面に順次堆積させて多孔質ガラス母材を製造す
る方法において、往復運動を基準点を中心に一方向に距
離Ｂだけ移動して折り返し、反対方向へ基準点から距離
Ｂだけ移動して折り返す方式で行い、距離Ｂをバーナ間
隔Ｌの１／２未満とし、かつ、ガラス微粒子堆積体の成
長に応じて変化させることを特徴とする多孔質ガラス母
材の製造方法。1. A plurality of burners for synthesizing glass fine particles are arranged so as to face a rotating starting rod, and the burner is synthesized by reciprocating the starting rod and the burner for synthesizing glass fine particles in parallel relatively. In a method for manufacturing a porous glass preform by sequentially depositing glass particles on the surface of a starting rod, a reciprocating motion is moved by a distance B in one direction around a reference point and folded back, and a distance B from the reference point in the opposite direction. The method for producing a porous glass preform is characterized in that the distance B is less than 1/2 of the burner interval L and is changed according to the growth of the glass particulate deposit body. 【請求項２】 前記距離Ｂをガラス微粒子堆積面におけ
る火炎の広がりを基準にして変化させることを特徴とす
る請求項１に記載の多孔質ガラス母材の製造方法。2. The method for producing a porous glass preform according to claim 1, wherein the distance B is changed with reference to the spread of the flame on the glass particulate deposition surface. 【請求項３】 火炎の広がりが、バーナ火炎の輝度分
布、ＣＣＤカメラ等による画像処理、及び温度測定装置
により測定される温度分布のうちの１つ以上の手段によ
り測定される値により定義されることを特徴とする請求
項２に記載の多孔質ガラス母材の製造方法。3. The spread of the flame is defined by a value measured by one or more means of a brightness distribution of the burner flame, image processing by a CCD camera or the like, and a temperature distribution measured by a temperature measuring device. The method for producing a porous glass preform according to claim 2, characterized in that. 【請求項４】 前記ＢがＢ＝（Ｌ−Ｘ）／２〔ただし、
Ｌ：バーナ間隔、Ｘ：ガラス微粒子堆積面における１つ
のバーナの火炎による堆積面の温度が所定温度以上とな
る範囲の長さ〕で定義される値であることを特徴とする
請求項３に記載の多孔質ガラス母材の製造方法。4. The B is B = (L−X) / 2 [wherein
L: burner interval, X: length of a range in which the temperature of the deposition surface due to the flame of one burner on the glass particulate deposition surface is equal to or higher than a predetermined temperature]. Of the porous glass base material of the above. 【請求項５】 前記往復運動の移動速度を５〜６００ｍ
ｍ／分とすることを特徴とする請求項１〜４のいずれか
１項に記載の多孔質ガラス母材の製造方法。5. The moving speed of the reciprocating motion is 5 to 600 m.
It is m / min, The manufacturing method of the porous glass base material of any one of Claims 1-4 characterized by the above-mentioned. 【請求項６】 往復運動の折り返し位置において、ガラ
ス微粒子合成用バーナによるガラス微粒子の発生量を調
整することを特徴とする請求項１〜５のいずれか１項に
記載の多孔質ガラス母材の製造方法。6. The porous glass preform according to claim 1, wherein the amount of glass fine particles generated by the burner for synthesizing glass fine particles is adjusted at the turning-back position of the reciprocating motion. Production method. 【請求項７】 前記ガラス微粒子発生量の調整を、ガラ
ス原料供給量を調整することによって行い、かつ、往復
運動定常部におけるバーナの火炎温度に対する火炎温度
の変化が±１５℃以内となる範囲で行うことを特徴とす
る請求項６に記載の多孔質ガラス母材の製造方法。7. The adjustment of the glass fine particle generation amount is performed by adjusting the glass raw material supply amount, and the change of the flame temperature with respect to the flame temperature of the burner in the reciprocating motion stationary part is within ± 15 ° C. The method for producing a porous glass preform according to claim 6, which is performed.
JP2001237797A 2001-08-06 2001-08-06 Method for manufacturing porous glass preform Withdrawn JP2003048722A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200255322A1 (en) * 2015-01-13 2020-08-13 Asi/Silica Machinery, Llc Enhanced Particle Deposition System and Method
WO2022158421A1 (en) * 2021-01-20 2022-07-28 古河電気工業株式会社 Device for manufacturing optical fiber preform and method for manufacturing optical fiber preform

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200255322A1 (en) * 2015-01-13 2020-08-13 Asi/Silica Machinery, Llc Enhanced Particle Deposition System and Method
US11993532B2 (en) * 2015-01-13 2024-05-28 Asi/Silica Machinery, Llc Enhanced particle deposition system and method
WO2022158421A1 (en) * 2021-01-20 2022-07-28 古河電気工業株式会社 Device for manufacturing optical fiber preform and method for manufacturing optical fiber preform

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