JP5762374B2 - Porous glass base material manufacturing equipment - Google Patents

Porous glass base material manufacturing equipment Download PDF

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JP5762374B2
JP5762374B2 JP2012206796A JP2012206796A JP5762374B2 JP 5762374 B2 JP5762374 B2 JP 5762374B2 JP 2012206796 A JP2012206796 A JP 2012206796A JP 2012206796 A JP2012206796 A JP 2012206796A JP 5762374 B2 JP5762374 B2 JP 5762374B2
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真 吉田
真 吉田
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Shin Etsu Chemical Co Ltd
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Description

本発明は、大型の多孔質ガラス母材を製造する場合においても、反応容器内の気流を安定させて火炎の乱れを抑制することができ、割れが発生しにくい多孔質ガラス母材の製造装置に関する。   Even when manufacturing a large porous glass base material, the present invention can stabilize the air flow in the reaction vessel and suppress the turbulence of the flame, and the device for manufacturing the porous glass base material that is less likely to crack About.

光ファイバの製造方法としては、VAD法は良く知られた方法である。
この方法では、回転しつつ上昇するシャフトに出発部材を取り付けて反応室内に垂下し、反応室内に設置されたコア堆積バーナ及びクラッド堆積バーナにより生成されたガラス微粒子を出発部材上に堆積させて、コア層とクラッド層からなる多孔質ガラス母材（以下、単に多孔質母材と称する）が製造される。 As a method for manufacturing an optical fiber, the VAD method is a well-known method.
In this method, a starting member is attached to a shaft that rises while rotating and is suspended in a reaction chamber, and glass fine particles generated by a core deposition burner and a cladding deposition burner installed in the reaction chamber are deposited on the starting member, A porous glass base material (hereinafter simply referred to as a porous base material) composed of a core layer and a clad layer is manufactured.

一般的に、このようなVAD装置で使用される反応容器は、複数本のバーナと、出発部材上にガラス微粒子の堆積を行う堆積室と、引上げられた多孔質母材が格納される円筒部から構成される。
ここで、生成されたガラス微粒子の堆積効率は100％とはならず、堆積されなかった未付着のガラス微粒子が、製造中、常に発生している。この未付着のガラス微粒子が、堆積中の多孔質母材に付着すると、透明ガラス化時に気泡が発生し、収率を大きく下げる。 In general, a reaction vessel used in such a VAD apparatus includes a plurality of burners, a deposition chamber for depositing glass fine particles on a starting member, and a cylindrical portion in which a pulled porous base material is stored. Consists of
Here, the deposition efficiency of the generated glass particles does not reach 100%, and unattached glass particles that have not been deposited are always generated during the production. When the unadhered glass fine particles adhere to the porous base material being deposited, bubbles are generated during the formation of transparent glass, greatly reducing the yield.

これを防止する方法として、特許文献１及び特許文献２に示されるように、空気を積極的に反応容器内に導き、反応容器内に線速の大きな整った気流を作り、これに反応容器内の未付着ガラス微粒子を載せることによって、効率的に堆積室内の排出口から排出させる方法が提案されている。   As a method for preventing this, as shown in Patent Document 1 and Patent Document 2, air is actively guided into the reaction vessel to create a well-balanced air stream having a high linear velocity in the reaction vessel. There has been proposed a method for efficiently discharging the unadhered glass particles from the discharge port in the deposition chamber.

特許第3,998,450号Patent 3,998,450 特許第4,466,997号Patent No. 4,466,997

従来は、図１に示すように、シャフト１に出発部材２を取り付け、図示されていない吊下げ機構により堆積室３内に垂下され、コア堆積用バーナ５、クラッド堆積用バーナ６，７により火炎加水分解で生成したガラス微粒子が出発部材２上に堆積され、形成された多孔質母材は円筒部４内に引き上げられる。なお、符号８a，８bは堆積室へのガス供給口、符号９は円筒部へのガス供給口であり、符号10はガス排出部である。   Conventionally, as shown in FIG. 1, a starting member 2 is attached to a shaft 1 and suspended in a deposition chamber 3 by a suspension mechanism (not shown), and flame is generated by a core deposition burner 5 and cladding deposition burners 6 and 7. Glass particles generated by hydrolysis are deposited on the starting member 2, and the formed porous base material is pulled up into the cylindrical portion 4. Reference numerals 8a and 8b are gas supply ports to the deposition chamber, reference numeral 9 is a gas supply port to the cylindrical portion, and reference numeral 10 is a gas discharge portion.

多孔質母材の安定した形状部が円筒部入口に入るまでの堆積初期においては、図２に示すように、円筒部内には、シャフト１もしくは出発部材２しか存在しないため、堆積室３の上部に大きな空間が存在するような形となり、堆積室３の上部に設けられたガス供給口８aから供給されたガスの一部が容積の大きな円筒部内に流れ込むため、ガス排出部10へと向かう堆積室内の気流13の乱れが非常に大きくなっていた。
ある程度堆積が進むと、図３に示すように、円筒部４内に多孔質母材12が入り込むことにより、円筒部４の内壁と多孔質母材12との間隙15が狭くなり、この間隙に流れ込む空気によって、円筒部４から堆積室３に流れ込む線速の大きな気流14ができ、堆積室の気流13は極めて安定する。 At the initial stage of deposition until the stable shape portion of the porous base material enters the entrance of the cylindrical portion, as shown in FIG. 2, only the shaft 1 or the starting member 2 exists in the cylindrical portion, so the upper portion of the deposition chamber 3 Since a part of the gas supplied from the gas supply port 8a provided at the upper part of the deposition chamber 3 flows into the large volume cylindrical portion, the deposition toward the gas discharge portion 10 is performed. The turbulence of the airflow 13 in the room was very large.
When the deposition proceeds to some extent, as shown in FIG. 3, the porous base material 12 enters the cylindrical portion 4, thereby narrowing the gap 15 between the inner wall of the cylindrical portion 4 and the porous base material 12. The air flowing in creates a large linear velocity air flow 14 flowing from the cylindrical portion 4 into the deposition chamber 3, and the air flow 13 in the deposition chamber is extremely stable.

このように気流が乱れた状態になるのは、堆積初期なので、未付着のガラス微粒子の付着といった問題は大きくないが、気流の乱れに伴って、火炎流が大きく乱れ、多孔質母材が安定して加熱されなくなる。
その結果、多孔質母材に割れが発生する確率が高くなるという問題が生じた。
特に、大型品を製造する反応容器は、格納する円筒部の内径を大きくしなければならないため、この影響が非常に大きい。 In this way, the airflow is disturbed because it is in the early stage of deposition, so the problem of adhesion of unattached glass particles is not significant, but the flame flow is greatly disturbed with the airflow disturbance, and the porous base material is stable. And no longer heated.
As a result, there arises a problem that the probability of cracking in the porous base material is increased.
In particular, a reaction vessel for producing a large product has a very large influence because the inner diameter of the cylindrical portion to be stored must be increased.

本発明の目的は、VAD法により大型の多孔質母材を製造する装置において、堆積初期における反応容器内の気流の乱れを防止し、多孔質母材の割れが発生しにくい多孔質母材の製造装置を提供することにある。   An object of the present invention is an apparatus for producing a large porous base material by the VAD method, which prevents turbulence of the air flow in the reaction vessel in the initial stage of deposition and prevents the porous base material from cracking. It is to provide a manufacturing apparatus.

鋭意検討の結果、形成された多孔質母材が円筒部に格納される前の堆積初期の状態において、円筒部内に整流部材を設置し、堆積室の気流が、円筒部のほうに行かないようにすることが効果的であることが判明し、本発明を達成した。
すなわち、本発明の多孔質母材の製造装置は、ガラス用原料、可燃性ガス及び助燃性ガスをバーナに供給して、ガラス原料を酸水素火炎中で加水分解してガラス微粒子を生成し、回転しつつ引上げられる出発部材に、生成したガラス微粒子を堆積して多孔質ガラス母材を製造する装置において、ガラス微粒子の堆積を行う堆積室と堆積された多孔質ガラス母材を堆積室上部に格納する円筒部とを有する反応容器において、該反応容器内に設置された出発部材の上部に、外径Ｄ２の円筒上部に外径Ｄ２の円板を組み付けてなる整流部材を配置し、前記円筒部の内径をＤ１とするとき、前記整流部材の外径Ｄ２がＤ２／Ｄ１≧０．８の関係を満たすことを特徴としている。
なお、前記整流部材は、円筒と該円筒の上部のみに、もしくは上下部のそれぞれに円板が組み付けられたものであっても良い。 As a result of intensive investigation, in the initial deposition state before the formed porous base material is stored in the cylindrical part, a rectifying member is installed in the cylindrical part so that the air flow in the deposition chamber does not go toward the cylindrical part. It was proved effective to achieve the present invention.
That is, the porous base material manufacturing apparatus of the present invention supplies glass raw material, combustible gas and auxiliary combustible gas to a burner, and hydrolyzes the glass raw material in an oxyhydrogen flame to produce glass fine particles, In an apparatus for producing a porous glass base material by depositing the generated glass fine particles on a starting member that is pulled up while rotating, a deposition chamber for depositing glass fine particles and a porous glass base material that has been deposited on the upper part of the deposition chamber. in a reaction vessel having a cylindrical portion for storing, on top of the installed starting member in the reaction vessel was placed a rectifying member in the cylindrical upper portion of the outer diameter D 2 formed by assembling a disc of outer diameter D 2, when the inner diameter of the cylindrical part and D 1, the outer diameter D 2 of the rectifying member is characterized by satisfying the relationship of D 2 / D 1 ≧ 0.8.
The rectifying member may be a cylinder and a disc assembled to only the upper part of the cylinder or the upper and lower parts.

本発明によれば、堆積初期における反応容器内の気流の乱れを防止することができ、多孔質母材の割れの発生を抑制することができる。   According to the present invention, it is possible to prevent the turbulence of the air flow in the reaction vessel at the initial stage of deposition, and to suppress the occurrence of cracks in the porous base material.

従来の製造装置の概略を示す縦断面図である。It is a longitudinal cross-sectional view which shows the outline of the conventional manufacturing apparatus. 従来の製造装置での堆積初期の気流の状態を示す模式図である。It is a schematic diagram which shows the state of the airflow of the initial stage of deposition in the conventional manufacturing apparatus. 従来の製造装置での堆積後半の気流の状態を示す模式図である。It is a schematic diagram which shows the state of the airflow of the second half of deposition in the conventional manufacturing apparatus. 本発明の製造装置の概略を示す縦断面図である。It is a longitudinal cross-sectional view which shows the outline of the manufacturing apparatus of this invention. 本発明の製造装置による堆積初期の気流の状態を示す模式図である。It is a schematic diagram which shows the state of the airflow of the initial stage of deposition by the manufacturing apparatus of this invention. （Ａ），（Ｂ）は、本発明の整流部材の概略を示す斜視図である。(A), (B) is a perspective view which shows the outline of the rectification | straightening member of this invention.

以下、本発明の実施の形態について説明するが、本発明はこれらに限定されるものではない。
図４に示すように、出発部材２の上部に円筒部４の内径よりも少し外径の小さな整流部材11を取付け、これをシャフト１に設置して、堆積を開始する。
その結果、図５に示すように、堆積初期においても、円筒部４よりも少し外径の小さな整流部材11が壁となるうえ、円筒部４の内壁と整流部材11との狭い間隙15から線速の大きな気流14が流れ出るので、堆積室内の気流13は、円筒部４の方に向かうことなく、ガス排出部10からスムーズに排気されていくようになる。 Hereinafter, although embodiment of this invention is described, this invention is not limited to these.
As shown in FIG. 4, a flow regulating member 11 having an outer diameter slightly smaller than the inner diameter of the cylindrical portion 4 is attached to the upper portion of the starting member 2, and this is installed on the shaft 1 to start deposition.
As a result, as shown in FIG. 5, even in the initial stage of deposition, the rectifying member 11 having a slightly smaller outer diameter than the cylindrical portion 4 becomes a wall, and a line is formed from a narrow gap 15 between the inner wall of the cylindrical portion 4 and the rectifying member 11. Since the high-speed air flow 14 flows out, the air flow 13 in the deposition chamber is smoothly exhausted from the gas discharge unit 10 without going toward the cylindrical portion 4.

この整流部材11を構成する円筒16の長さＬは、取付け、取り出し工程で干渉しない範囲で、出来るだけ長いほうが効果は大きい。
また、円筒16に組み合わせる円板17は、図６（Ａ）では、円筒16の上部に取り付けられているが、円筒16の下部に取り付けても良く、また図６（Ｂ）のように、円筒16の上下両方につけても良い。 As long as the length L of the cylinder 16 constituting the rectifying member 11 does not interfere with the attachment and removal processes, the effect is larger as long as possible.
Further, the disk 17 to be combined with the cylinder 16 is attached to the upper part of the cylinder 16 in FIG. 6A, but it may be attached to the lower part of the cylinder 16 or as shown in FIG. 6B. It may be attached to both the top and bottom of 16.

図４に示すような堆積室３と内径250mmφの円筒部４からなる反応容器を用意し、堆積室３には、上の給気口８aから1000〔L/min〕、下の給気口８bから200〔L/min〕の空気をそれぞれ供給し、円筒部４には、給気口９から300〔L/min〕の空気を供給した。
出発部材２として、外径30mmφ、長さ500mmの石英ガラス材を用意し、これに７種類の外径（160〜220mm）で作成した整流部材11（長さＬ＝150mm）を取り付けて、シャフト１に吊り下げた。 A reaction vessel comprising a deposition chamber 3 and a cylindrical portion 4 having an inner diameter of 250 mmφ as shown in FIG. 4 is prepared. The deposition chamber 3 has an upper supply port 8a to 1000 [L / min] and a lower supply port 8b. 200 [L / min] was supplied from the air supply port 9, and 300 [L / min] air was supplied to the cylindrical portion 4 from the air supply port 9.
A quartz glass material with an outer diameter of 30 mmφ and a length of 500 mm is prepared as the starting member 2, and a straightening member 11 (length L = 150 mm) created with seven types of outer diameters (160 to 220 mm) is attached to the shaft. 1 suspended.

ここで、堆積室３に設置したコア堆積用バーナ５には、原料ガスとして500〔ml/min〕のSiCl４と20〔ml/min〕のGeCl４を供給した。クラッド堆積用バーナ６，７には原料ガスとしてそれぞれ1.0〔l/min〕、3.5〔l/min〕のSiCl４を供給した。さらに、各堆積用バーナには、それぞれ燃焼ガスとしてＨ２を、助燃ガスとしてＯ２を供給した。
このようにして堆積を行い、長さ1000mmの多孔質母材を各30本ずつ得た。また、比較用として、整流部材を設置しない条件でも堆積を行った。その結果を表１に示す。 Here, the core deposition burner 5 installed in the deposition chamber 3 was supplied with 500 [ml / min] SiCl 4 and 20 [ml / min] GeCl 4 as source gases. The cladding deposition burners 6 and 7 were supplied with 1.0 [l / min] and 3.5 [l / min] SiCl 4 as source gases, respectively. Further, each deposition burner was supplied with H 2 as a combustion gas and O 2 as an auxiliary combustion gas.
Deposition was carried out in this way, and 30 porous substrates each having a length of 1000 mm were obtained. For comparison, deposition was also performed under the condition that no rectifying member was installed. The results are shown in Table 1.

Figure 0005762374
Figure 0005762374

その結果、25本に割れが発生したが、その全てが、多孔質母材が円筒部に入る前の堆積初期に発生したものであった。
その中でも、整流板を設置しなかった条件Ｈは、堆積初期の気流の乱れが大きく、多孔質母材が円筒部に入る前の堆積初期に、10/30本が割れてしまい、最も割れ数が多かった。
整流部材を設置したものの中では、整流部材11の外径Ｄ２が円筒部４の内径Ｄ1に対して小さいものほど割れた多孔質母材の数が多く、Ｄ２/Ｄ1≧0.8のものには、割れが発生しなかった。整流部材11の外径Ｄ２が小さいと、邪魔板効果が小さくなるとともに、円筒とのクリアランスが狭くならないので、間隙15を流れる空気の線速が大きくならず、堆積室３内の気流13を安定した状態に抑え込むことができない。 As a result, 25 cracks occurred, all of which occurred in the initial stage of deposition before the porous base material entered the cylindrical portion.
Among them, the condition H in which the rectifying plate was not installed is that the turbulence of the air flow at the initial stage of deposition was large, and 10/30 pieces were cracked at the initial stage of deposition before the porous base material entered the cylindrical portion. There were many.
Among those in which the rectifying member is installed, the smaller the outer diameter D 2 of the rectifying member 11 is smaller than the inner diameter D 1 of the cylindrical portion 4, the more porous base material is broken, and D 2 / D 1 ≧ 0.8 The thing did not crack. When the outer diameter D 2 of the straightening member 11 is small, with the baffle effect is small and the clearance between the cylinder does not become narrow, not linear velocity of the air flowing through the gap 15 is large, the air flow 13 in the deposition chamber 3 It cannot be held down to a stable state.

１．シャフト、
２．出発部材、
３．堆積室、
４．円筒部、
５．コア堆積用バーナ、
６，７．クラッド堆積用バーナ、
８a，８b，９．ガス供給口、
１０．ガス排出部、
１１．整流部材、
１２．多孔質母材、
１３，１４．気流、
１５．間隙、
１６．円筒、
１７．円板。 1. shaft,
2. Starting material,
3. Deposition chamber,
4). Cylindrical part,
5. Burner for core deposition,
6,7. Burner for clad deposition,
8a, 8b, 9. Gas supply port,
10. Gas exhaust,
11. Rectifying member,
12 Porous matrix,
13,14. air flow,
15. gap,
16. Cylinder,
17. Disc.

Claims (2)

ガラス用原料、可燃性ガス及び助燃性ガスをバーナに供給して、ガラス原料を酸水素火炎中で加水分解してガラス微粒子を生成し、回転しつつ引上げられる出発部材に、生成したガラス微粒子を堆積して多孔質ガラス母材を製造する装置において、ガラス微粒子の堆積を行う堆積室と堆積された多孔質ガラス母材を堆積室上部に格納する円筒部とを有する反応容器において、該反応容器内に設置された出発部材の上部に、外径Ｄ２の円筒上部に外径Ｄ２の円板を組み付けてなる整流部材を配置し、前記円筒部の内径をＤ１とするとき、前記整流部材の外径Ｄ２がＤ２／Ｄ１≧０．８の関係を満たすことを特徴とする多孔質ガラス母材の製造装置。 The raw material for glass, the combustible gas and the auxiliary combustible gas are supplied to the burner, the glass raw material is hydrolyzed in an oxyhydrogen flame to generate glass fine particles, and the generated glass fine particles are used as a starting member that is pulled up while rotating. In an apparatus for depositing and manufacturing a porous glass base material, a reaction vessel having a deposition chamber for depositing glass fine particles and a cylindrical portion for storing the deposited porous glass base material in the upper portion of the deposition chamber, on top of the installed starting member within the straightener member in the cylindrical upper portion of the outer diameter D 2 formed by assembling a disc of outer diameter D 2 is disposed, the inner diameter of the cylindrical portion when the D 1, the rectifier An apparatus for producing a porous glass base material, wherein an outer diameter D 2 of the member satisfies a relationship of D 2 / D 1 ≧ 0.8. 前記整流部材が、円筒と該円筒の上下部にそれぞれ円板が組み付けられている請求項１に記載の多孔質ガラス母材の製造装置。 The apparatus for producing a porous glass base material according to claim 1, wherein the straightening member has a cylinder and discs respectively assembled to the upper and lower portions of the cylinder.
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