JP3682383B2 - Heating furnace for dehydration sintering of porous glass base material - Google Patents

Heating furnace for dehydration sintering of porous glass base material Download PDF

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Publication number
JP3682383B2
JP3682383B2 JP02723899A JP2723899A JP3682383B2 JP 3682383 B2 JP3682383 B2 JP 3682383B2 JP 02723899 A JP02723899 A JP 02723899A JP 2723899 A JP2723899 A JP 2723899A JP 3682383 B2 JP3682383 B2 JP 3682383B2
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core tube
base material
weight
furnace
porous glass
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JP2000226217A (en
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伸昭 折田
聡 杉山
昌之 坂本
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THE FURUKAW ELECTRIC CO., LTD.
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THE FURUKAW ELECTRIC 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

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脱水し、焼結して透明ガラス化するための多孔質ガラス母材の脱水焼結用加熱炉に関するものである。
【０００２】
【従来の技術】
図４及び図５は、従来のこの種の多孔質ガラス母材の脱水焼結用加熱炉の２種の構造を示したものである。
【０００３】
これらの多孔質ガラス母材の脱水焼結用加熱炉は、炉体１の中心部を貫通していて内部に多孔質ガラス母材２を収容する石英ガラス等よりなる炉心管３と、炉体１内で炉心管３の周囲に配置されて該炉心管３内の多孔質ガラス母材２を加熱する電気ヒータの如き発熱体４と、炉心管３と発熱体４との間で炉心管３の外周を包囲して配置されたマッフル管５と、このマッフル管５の外側で炉体１の内壁に沿って配置された断熱材６とを主体として構成されている。図４に示す脱水焼結用加熱炉においては発熱体４が１個の場合の例を示し、図５に示す脱水焼結用加熱炉においては発熱体４が複数個（この例では、５個）の場合の例を示している。炉心管３は、その上部外周に一体に突設された石英製の環状の鍔部７が炉体１の上面１ａに載ることにより、またその下部外周に一体に突設された石英製の環状の鍔部７が炉体１の底面１ｂに載ることにより、炉体１に支持されている。炉心管３の上端は上蓋８により塞がれており、この上蓋８には多孔質ガラス母材２の出発母材２ａを貫通させる孔９があけられている。炉心管３の下端には処理ガス導入口１０が設けられ、炉心管３内にＨｅガスやＣｌ２ ガス等が供給されるようになっている。炉心管３の上部には、炉心管３内の排気ガスを排出する排気口１１が設けられている。炉体１内には、ＡｒガスやＮ２ ガス等の不活性ガスが供給させるようになっている。
【０００４】
このような脱水焼結用加熱炉を用いた多孔質ガラス母材２の脱水，焼結は、図４に示す発熱体４が１個の場合には、該発熱体４を炉体１内の上下方向に動かすか、固定された発熱体４に対して多孔質ガラス母材２を上下方向に動かすことにより行われ、図５に示す発熱体４が複数個の場合には、各発熱体４への通電を切り換えて各発熱体４がそれぞれ作る加熱ゾーンを上下方向に動かすことにより行われる。
【０００５】
【発明が解決しようとする課題】
近年、光ファイバの需要増加に伴い、光ファイバ用の多孔質ガラス母材２の大型化と長尺化が進み、これを脱水焼結してガラス化するための大型の加熱炉が必要になってきている。しかしながら、大型で長尺の多孔質ガラス母材２を脱水焼結する際には、石英製の炉心管３が広範囲に渡って1500 ℃以上に加熱されるため、石英が軟化して炉心管３が自重で座屈変形してしまう問題点があった。
【０００６】
本発明の目的は、高温加熱時に炉心管が自重により座屈変形するのを防止できる多孔質ガラス母材の脱水焼結用加熱炉を提供することにある。
【０００７】
本発明の他の目的は、高温加熱時に炉心管が自重により座屈変形するのをマッフル管を利用して防止できる多孔質ガラス母材の脱水焼結用加熱炉を提供することにある。
【０００８】
【課題を解決するための手段】
本発明は、炉体の中心部を貫通していて内部に多孔質ガラス母材を収容する炉心管と、炉体内で炉心管の周囲に配置されて該炉心管内の多孔質ガラス母材を加熱する発熱体とを備えた多孔質ガラス母材の脱水焼結用加熱炉を改良するものである。
【０００９】
請求項１に記載の多孔質ガラス母材の脱水焼結用加熱炉は、炉心管の加熱を受ける部分の外周には該炉心管自身の自重をその長手方向に分割負担する炉心管自重分割負担手段が設けられていることを特徴とする。
【００１０】
このように炉心管の加熱を受ける部分の外周に、該炉心管自身の自重をその長手方向に分割負担する炉心管自重分割負担手段を設けると、炉心管自身の自重が該炉心管の長手方向の複数箇所で分割負担されるので、高温加熱時に炉心管が自重により座屈変形するのを防止することができる。
【００１１】
請求項２に記載の多孔質ガラス母材の脱水焼結用加熱炉は、請求項１において、炉心管自重分割負担手段が、炉心管の加熱を受ける部分の外周にその長手方向に所定間隔で突設された複数の鍔部と、炉心管の加熱を受ける部分の外周で各鍔部を支える炉心管自重受け手段とで構成されていることを特徴とする。
【００１２】
このように炉心管の加熱を受ける部分の外周にその長手方向に所定間隔で突設された複数の鍔部と、炉心管の加熱を受ける部分の外周で各鍔部を支える炉心管自重受け手段とで炉心管自重分割負担手段を構成すると、炉心管自身の自重をその長手方向の複数箇所で容易に分割負担させることができる。
【００１３】
請求項３に記載の多孔質ガラス母材の脱水焼結用加熱炉は、請求項２において、炉心管自重受け手段が、上下に隣接する各鍔部の間で炉心管の加熱を受ける部分の外周にそれぞれ介在されて上側の鍔部に作用する炉心管の自重を負担するマッフル管により構成されていることを特徴とする。
【００１４】
このように炉心管自重受け手段を構成すると、短尺の複数のマッフル管を利用して炉心管自重受け手段を構成することができる。
【００１５】
請求項４に記載の多孔質ガラス母材の脱水焼結用加熱炉は、請求項２において、炉心管自重受け手段が、炉心管の加熱を受ける部分の外周に沿って配置されたマッフル管と、炉心管の各鍔部に対応してマッフル管にそれぞれ設けられて各鍔部を支える複数の支え部とにより構成されていることを特徴とする。
【００１６】
このように炉心管自重受け手段を構成すると、長手方向に所定間隔で支え部を設けたマッフル管を利用して炉心管自重受け手段を構成することができる。
【００１７】
【発明の実施の形態】
図１（Ａ）（Ｂ）は本発明に係る多孔質ガラス母材の脱水焼結用加熱炉における実施の形態の第１例を示したもので、図１（Ａ）は該脱水焼結用加熱炉の縦断端面図、図１（Ｂ）は該脱水焼結用加熱炉で用いている炉心管自重分割負担手段の構成を示す斜視図である。本例は、前述した図５に示す複数の発熱体４を有するタイプの脱水焼結用加熱炉に本発明を適用した例を示したもので、該図５と対応する部分には、同一符号を付けて示している。
【００１８】
本例の多孔質ガラス母材の脱水焼結用加熱炉においては、石英製の炉心管３の加熱を受ける部分の外周に、該炉心管３自身の自重をその長手方向に分割負担する炉心管自重分割負担手段１３が設けられている。この炉心管自重分割負担手段１３は、炉心管３の中間部の加熱を受ける部分の外周にその長手方向に所定間隔で一体に環状に突設された石英製の複数の鍔部７と、炉心管３の加熱を受ける部分の外周で各鍔部７を支える炉心管自重受け手段１４とで構成されている。本例では、炉心管自重受け手段１４は、上下に隣接する各鍔部７の間で炉心管３の加熱を受ける部分の外周にそれぞれ介在されて上側の鍔部７に作用する炉心管３の自重を負担する短尺のマッフル管５により構成されている。これら短尺のマッフル管５は、上下に隣接する各鍔部７間の長さに設定され、その装着を容易にするために長手方向に沿って割り部５ａが設けられた２つ割り構造になっている。これらマッフル管５は、炭素繊維強化炭素等により構成されている。
【００１９】
このように炉心管３の加熱を受ける部分の外周に、該炉心管３自身の自重をその長手方向に分割負担する炉心管自重分割負担手段１３を設けると、炉心管３自身の自重が該炉心管３の長手方向の複数箇所で分割負担されるので、高温加熱時に炉心管３が自重により座屈変形するのを防止することができる。
【００２０】
また、炉心管自重分割負担手段１３が、炉心管３の加熱を受ける部分の外周にその長手方向に所定間隔で突設された複数の鍔部７と、炉心管３の加熱を受ける部分の外周で各鍔部７を支える炉心管自重受け手段１４とで構成されていると、炉心管３自身の自重をその長手方向の複数箇所で容易に分割負担させることができる。
【００２１】
特に、本例のように炉心管自重受け手段１４が、上下に隣接する各鍔部７の間で炉心管３の加熱を受ける部分の外周にそれぞれ介在されて上側の鍔部７に作用する炉心管３の自重を負担するマッフル管５により構成されていると、短尺の複数のマッフル管５を利用して炉心管自重受け手段１４を構成することができる。
【００２２】
図２（Ａ）（Ｂ）は本発明に係る多孔質ガラス母材の脱水焼結用加熱炉における実施の形態の第２例を示したもので、図２（Ａ）は該脱水焼結用加熱炉の縦断端面図、図２（Ｂ）は該脱水焼結用加熱炉で用いている炉心管自重分割負担手段の構成を示す斜視図である。本例も、前述した図５に示す複数の発熱体４を有するタイプの脱水焼結用加熱炉に本発明を適用した例を示したものである。なお、前述した図１（Ａ）（Ｂ）と対応する部分には、同一符号を付けて示している。
【００２３】
本例の多孔質ガラス母材の脱水焼結用加熱炉においては、石英製の炉心管３の加熱を受ける部分の外周に、該炉心管３自身の自重をその長手方向に分割負担する炉心管自重分割負担手段１３が設けられ、この炉心管自重分割負担手段１３が、炉心管３の中間部の加熱を受ける部分の外周にその長手方向に所定間隔で一体に環状に突設された石英製の複数の鍔部７と、炉心管３の加熱を受ける部分の外周で各鍔部７を支える炉心管自重受け手段１４とで構成されている点は、第１例と同様である。
【００２４】
特に、本例の脱水焼結用加熱炉においては、炉心管自重受け手段１４が、炉心管３の加熱を受ける部分の外周に沿って配置されたマッフル管５と、炉心管３の各鍔部７に対応してマッフル管５にそれぞれ設けられて各鍔部７を支える複数の支え部１５とにより構成されている。このマッフル管５も、炭素繊維強化炭素等により構成されている。所要長さのマッフル管５の内周に長手方向に所定間隔で支え部１５を設けるために、本例では短尺のマッフル管５を支え部１５を介して交互に連結している。
【００２５】
このように炉心管自重受け手段１４を構成すると、長手方向に所定間隔で支え部１５を設けたマッフル管５を利用して炉心管自重受け手段１４を構成することができる。
【００２６】
図３は本発明に係る多孔質ガラス母材の脱水焼結用加熱炉における実施の形態の第３例を示した縦断端面図である。本例は、前述した図４に示す１つの発熱体４を有するタイプの脱水焼結用加熱炉に本発明を適用した例を示したものである。なお、前述した図１（Ａ）（Ｂ）と対応する部分には、同一符号を付けて示している。
【００２７】
本例の多孔質ガラス母材の脱水焼結用加熱炉においては、図１（Ａ）（Ｂ）に示す第１例が複数の発熱体４を有するタイプであるのに対し、本例では１つの発熱体４を有するタイプである点で相違し、その他の構成、特に炉心管自重分割負担手段１３の構成は図１（Ａ）（Ｂ）に示す第１例と同様である。
【００２８】
従って、炉心管自重分割負担手段１３による効果については、図１（Ａ）（Ｂ）に示す第１例と同様である。
【００２９】
【発明の効果】
本発明に係る多孔質ガラス母材の脱水焼結用加熱炉では、炉心管の加熱を受ける部分の外周に、該炉心管自身の自重をその長手方向に分割負担する炉心管自重分割負担手段を設けているので、炉心管自身の自重が該炉心管の長手方向の複数箇所で分割負担されるので、高温加熱時に炉心管が自重により座屈変形するのを防止することができる。
【図面の簡単な説明】
【図１】 （Ａ）（Ｂ）は本発明に係る多孔質ガラス母材の脱水焼結用加熱炉における実施の形態の第１例を示したもので、（Ａ）は該脱水焼結用加熱炉の縦断端面図、（Ｂ）は該脱水焼結用加熱炉で用いている炉心管自重分割負担手段の構成を示す斜視図である。
【図２】 （Ａ）（Ｂ）は本発明に係る多孔質ガラス母材の脱水焼結用加熱炉における実施の形態の第２例を示したもので、（Ａ）は該脱水焼結用加熱炉の縦断端面図、（Ｂ）は該脱水焼結用加熱炉で用いている炉心管自重分割負担手段の構成を示す斜視図である。
【図３】 本発明に係る多孔質ガラス母材の脱水焼結用加熱炉における実施の形態の第３例を示した縦断端面図である。
【図４】 発熱体が１個の場合の従来の多孔質ガラス母材の脱水焼結用加熱炉の構造を示す縦断端面図である。
【図５】 発熱体が複数個の場合の従来の多孔質ガラス母材の脱水焼結用加熱炉の構造を示す縦断端面図である。
【符号の説明】
１ 炉体
１ａ 上面
１ｂ 底面
２ 多孔質ガラス母材
２ａ 出発母材
３ 炉心管
４ 発熱体
５ マッフル管
５ａ 割り部
６ 断熱材
７ 鍔部
８ 上蓋
９ 孔
１０ 処理ガス導入口
１１ 排気口
１３ 炉心管自重分割負担手段
１４ 炉心管自重受け手段
１５ 支え部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a furnace for dehydration and sintering of a porous glass base material for dehydrating and sintering a porous glass base material to form a transparent glass.
[0002]
[Prior art]
4 and 5 show two types of conventional furnaces for dehydration sintering of this kind of porous glass base material.
[0003]
A furnace for dehydration and sintering of these porous glass base materials includes a furnace core tube 3 made of quartz glass or the like that penetrates the center of the furnace body 1 and accommodates the porous glass base material 2 therein, and a furnace body. 1 is disposed around the core tube 3 within the furnace core 3, and a heating element 4 such as an electric heater for heating the porous glass preform 2 in the core tube 3, and the core tube 3 between the core tube 3 and the heating element 4. Are mainly composed of a muffle tube 5 disposed so as to surround the outer periphery thereof and a heat insulating material 6 disposed along the inner wall of the furnace body 1 outside the muffle tube 5. In the dehydration sintering heating furnace shown in FIG. 4, an example in which there is one heating element 4 is shown, and in the dehydration sintering heating furnace shown in FIG. 5, a plurality of heating elements 4 (in this example, five heating elements 4 are used). ) Shows an example. The reactor core tube 3 has a quartz ring-shaped flange 7 integrally projecting from the upper outer periphery thereof and is mounted on the upper surface 1a of the furnace body 1 and a quartz ring projecting integrally from the lower outer periphery thereof. Is supported by the furnace body 1 by placing the flange portion 7 on the bottom surface 1 b of the furnace body 1. The upper end of the core tube 3 is closed by an upper lid 8, and a hole 9 through which the starting base material 2 a of the porous glass base material 2 passes is formed in the upper lid 8. A processing gas inlet 10 is provided at the lower end of the core tube 3, and He gas, Cl 2 gas, and the like are supplied into the core tube 3. An exhaust port 11 for exhausting exhaust gas in the core tube 3 is provided on the top of the core tube 3. An inert gas such as Ar gas or N 2 gas is supplied into the furnace body 1.
[0004]
The dehydration and sintering of the porous glass base material 2 using such a heating furnace for dehydration sintering is performed when the heating element 4 shown in FIG. This is performed by moving the porous glass base material 2 in the vertical direction or by moving the porous glass base material 2 in the vertical direction with respect to the fixed heating element 4. When there are a plurality of heating elements 4 shown in FIG. This is performed by moving the heating zones formed by the respective heating elements 4 in the vertical direction by switching the energization to.
[0005]
[Problems to be solved by the invention]
In recent years, with the increase in demand for optical fibers, the size and length of the porous glass preform 2 for optical fibers have been increased, and a large heating furnace is required to dehydrate and sinter the glass. It is coming. However, when the large and long porous glass base material 2 is dehydrated and sintered, the quartz core tube 3 is heated to 1500 ° C. or more over a wide range, so that the quartz is softened and the core tube 3 is softened. However, there was a problem that buckled and deformed by its own weight.
[0006]
An object of the present invention is to provide a furnace for dehydration and sintering of a porous glass base material that can prevent a furnace core tube from buckling due to its own weight during high-temperature heating.
[0007]
Another object of the present invention is to provide a heating furnace for dehydration and sintering of a porous glass base material that can prevent a furnace core tube from buckling and deforming due to its own weight during high-temperature heating using a muffle tube.
[0008]
[Means for Solving the Problems]
The present invention includes a core tube that passes through the center of the furnace body and accommodates the porous glass base material therein, and is disposed around the core tube within the furnace body to heat the porous glass base material in the core tube. And a heating furnace for dehydration sintering of a porous glass base material provided with a heating element.
[0009]
The furnace for dehydration and sintering of a porous glass preform according to claim 1, wherein the core tube self-weight division burden is obtained by dividing the weight of the core tube itself in the longitudinal direction on the outer periphery of the portion to be heated by the core tube. Means are provided.
[0010]
In this way, when a reactor core tube self-weight division burdening means is provided on the outer periphery of the portion subjected to heating of the reactor core tube, the reactor core tube self-weight splitting means for dividing and burdening the reactor core tube itself in the longitudinal direction, the reactor core tube itself is subjected to its own weight in the longitudinal direction of the reactor core tube. Therefore, it is possible to prevent the core tube from being buckled and deformed by its own weight during high-temperature heating.
[0011]
A heating furnace for dehydration and sintering of a porous glass base material according to claim 2 is the heating furnace according to claim 1, wherein the core tube self-weight division burdening means is provided at a predetermined interval in the longitudinal direction on the outer periphery of the portion where the core tube is heated. It is characterized by comprising a plurality of protruding flanges and a core tube self-weight receiving means for supporting each flange on the outer periphery of the portion where the core tube is heated .
[0012]
Thus a plurality of flange portions which protrude at predetermined intervals in the longitudinal direction on the outer periphery of the portion receiving the heat of the core tube, core tube own weight receiving means for supporting the respective flange portions at the outer periphery of the portion receiving the heat of the core tube If the core tube self-weight division burden means is configured, the self-weight of the core tube itself can be easily divided and burdened at a plurality of locations in the longitudinal direction.
[0013]
A heating furnace for dehydration and sintering of a porous glass base material according to claim 3 is the heating furnace according to claim 2, wherein the core tube self-weight receiving means receives the heating of the core tube between upper and lower adjacent flanges . It is characterized by comprising a muffle tube that bears the weight of the core tube that is interposed on the outer periphery and acts on the upper flange.
[0014]
If the core tube self-weight receiving means is configured in this way, the core tube self-weight receiving means can be configured using a plurality of short muffle tubes.
[0015]
A heating furnace for dehydration and sintering of a porous glass base material according to claim 4 is the muffle tube according to claim 2, wherein the core tube self-weight receiving means is disposed along the outer periphery of the portion that receives the heating of the core tube. The muffle tube includes a plurality of support portions that are provided in the muffle tube corresponding to the flange portions of the core tube and support the flange portions.
[0016]
If the core tube self-weight receiving means is configured as described above, the core tube self-weight receiving means can be configured using a muffle tube provided with support portions at predetermined intervals in the longitudinal direction.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
1A and 1B show a first example of an embodiment of a heating furnace for dehydration sintering of a porous glass base material according to the present invention, and FIG. FIG. 1B is a perspective view showing the configuration of the core weight self-loading division means used in the dehydration sintering heating furnace. This example shows an example in which the present invention is applied to a heating furnace for dehydration sintering of the type having the plurality of heating elements 4 shown in FIG. 5 described above, and parts corresponding to those in FIG. It shows with.
[0018]
In the heating furnace for dehydration and sintering of the porous glass base material of the present example, a core tube that divides and bears the own weight of the core tube 3 itself in the longitudinal direction on the outer periphery of the portion of the quartz core tube 3 that is heated. A self-weight division burdening means 13 is provided. The core tube self-weight division burdening means 13 includes a plurality of quartz flanges 7 that project integrally and annularly at predetermined intervals in the longitudinal direction on the outer periphery of a portion of the core tube 3 that is heated in the middle, and the core It is comprised with the core tube self weight receiving means 14 which supports each collar part 7 in the outer periphery of the part which receives the heating of the pipe | tube 3. As shown in FIG. In the present example, the core tube self-weight receiving means 14 is interposed between the upper and lower adjacent flanges 7 on the outer periphery of the portion where the core tube 3 is heated, and acts on the upper flange 7. It is composed of a short muffle tube 5 that bears its own weight. These short muffle pipes 5 are set to the length between the flanges 7 adjacent to each other in the vertical direction, and have a split structure in which a split part 5a is provided along the longitudinal direction in order to facilitate the mounting thereof. ing. These muffle tubes 5 are made of carbon fiber reinforced carbon or the like.
[0019]
When the core tube self-weight splitting means 13 for splitting the weight of the core tube 3 itself in the longitudinal direction is provided on the outer periphery of the portion where the core tube 3 is heated , the core tube 3 itself has its own weight. Since the burden is divided at a plurality of locations in the longitudinal direction of the tube 3, it is possible to prevent the core tube 3 from being buckled and deformed by its own weight during high-temperature heating.
[0020]
Further, the core tube self-weight division burdening means 13 has a plurality of flanges 7 projecting at a predetermined interval in the longitudinal direction on the outer periphery of the portion where the core tube 3 is heated, and the outer periphery of the portion where the core tube 3 is heated. Thus, if the core tube self-weight receiving means 14 that supports each flange 7 is configured, the self-weight of the core tube 3 itself can be easily divided and divided at a plurality of locations in the longitudinal direction.
[0021]
In particular, as in the present example, the core tube weight receiving means 14 is interposed on the outer periphery of the portion where the core tube 3 is heated between the upper and lower adjacent flange portions 7 and acts on the upper flange portion 7. When the muffle tube 5 that bears the weight of the tube 3 is used, the core tube self-weight receiving means 14 can be configured using a plurality of short muffle tubes 5.
[0022]
2 (A) and 2 (B) show a second example of the embodiment in the heating furnace for dehydration sintering of the porous glass base material according to the present invention, and FIG. 2 (A) is for the dehydration sintering. FIG. 2 (B) is a perspective view showing the configuration of the furnace core tube self-weight division burdening means used in the heating furnace for dehydration sintering. This example also shows an example in which the present invention is applied to a heating furnace for dehydration sintering of the type having the plurality of heating elements 4 shown in FIG. Note that portions corresponding to those in FIGS. 1A and 1B are denoted by the same reference numerals.
[0023]
In the heating furnace for dehydration and sintering of the porous glass base material of the present example, a core tube that divides and bears the own weight of the core tube 3 itself in the longitudinal direction on the outer periphery of the portion of the quartz core tube 3 that is heated. A self-weight division burdening means 13 is provided, and this core weight self-weight division burdening means 13 is made of quartz, which protrudes in an annular shape integrally with a predetermined interval in the longitudinal direction on the outer periphery of the portion that receives the heating of the intermediate part of the core tube 3. These are the same as in the first example in that the plurality of flanges 7 and the core tube weight receiving means 14 that supports the flanges 7 on the outer periphery of the portion that receives the heating of the core tube 3 are configured.
[0024]
In particular, in the heating furnace for dehydration and sintering of this example, the core tube self-weight receiving means 14 includes the muffle tube 5 disposed along the outer periphery of the portion where the core tube 3 is heated, and the flanges of the core tube 3. 7 and a plurality of support portions 15 that are provided on the muffle tube 5 and support the flanges 7 respectively. The muffle tube 5 is also made of carbon fiber reinforced carbon or the like. In order to provide the support portions 15 at predetermined intervals in the longitudinal direction on the inner periphery of the muffle tube 5 having a required length, in this example, the short muffle tubes 5 are alternately connected via the support portions 15.
[0025]
If the core tube self-weight receiving means 14 is configured in this way, the core tube self-weight receiving means 14 can be configured using the muffle tube 5 provided with the support portions 15 at predetermined intervals in the longitudinal direction.
[0026]
FIG. 3 is a longitudinal end view showing a third example of the embodiment in the heating furnace for dehydration sintering of the porous glass base material according to the present invention. This example shows an example in which the present invention is applied to a heating furnace for dehydration sintering of the type having the one heating element 4 shown in FIG. Note that portions corresponding to those in FIGS. 1A and 1B are denoted by the same reference numerals.
[0027]
In the heating furnace for dehydration and sintering of the porous glass base material of this example, the first example shown in FIGS. 1A and 1B is a type having a plurality of heating elements 4, whereas in this example, 1 It differs in that it is a type having two heating elements 4, and other configurations, in particular, the configuration of the reactor core tube self-weight division burden means 13 are the same as those in the first example shown in FIGS.
[0028]
Accordingly, the effect of the core tube self-weight division burdening means 13 is the same as that of the first example shown in FIGS.
[0029]
【The invention's effect】
In the heating furnace for dehydration and sintering of the porous glass base material according to the present invention, the core tube self-weight division burdening means for splitting the weight of the core tube itself in the longitudinal direction is provided on the outer periphery of the portion to be heated of the core tube. Since it is provided, the own weight of the core tube itself is divided and burdened at a plurality of locations in the longitudinal direction of the core tube, so that it is possible to prevent the core tube from being buckled and deformed by its own weight during high temperature heating.
[Brief description of the drawings]
FIGS. 1A and 1B show a first example of an embodiment of a heating furnace for dehydration sintering of a porous glass base material according to the present invention, and FIG. A longitudinal end view of the heating furnace, (B) is a perspective view showing the configuration of the furnace core tube self-weight division burden means used in the heating furnace for dehydration sintering.
FIGS. 2A and 2B show a second example of an embodiment of a heating furnace for dehydration sintering of a porous glass base material according to the present invention, and FIG. A longitudinal end view of the heating furnace, (B) is a perspective view showing the configuration of the furnace core tube self-weight division burden means used in the heating furnace for dehydration sintering.
FIG. 3 is a longitudinal end view showing a third example of the embodiment in the heating furnace for dehydration sintering of the porous glass base material according to the present invention.
FIG. 4 is a longitudinal end view showing the structure of a conventional furnace for dehydration and sintering of a porous glass base material when there is one heating element.
FIG. 5 is a longitudinal end view showing the structure of a conventional furnace for dehydration and sintering of a porous glass base material when a plurality of heating elements are used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Furnace 1a Upper surface 1b Bottom surface 2 Porous glass base material 2a Starting base material 3 Furnace core tube 4 Heating element 5 Muffle tube 5a Split part 6 Heat insulating material 7 Gutter part 8 Top cover 9 Hole 10 Process gas introduction port 11 Exhaust port 13 Core tube Self-weight division burden means 14 Reactor core weight receiving means 15 Support section

Claims (4)

炉体の中心部を貫通していて内部に多孔質ガラス母材を収容する炉心管と、前記炉体内で前記炉心管の周囲に配置されて該炉心管内の前記多孔質ガラス母材を加熱する発熱体とを備えた多孔質ガラス母材の脱水焼結用加熱炉において、
前記炉心管の加熱を受ける部分の外周には該炉心管自身の自重をその長手方向に分割負担する炉心管自重分割負担手段が設けられていることを特徴とする多孔質ガラス母材の脱水焼結用加熱炉。A core tube that passes through the center of the furnace body and accommodates the porous glass base material therein, and is disposed around the core tube within the furnace body to heat the porous glass base material in the core tube. In a heating furnace for dehydration sintering of a porous glass base material provided with a heating element,
A furnace core tube self-weight splitting means for splitting the weight of the core tube itself in the longitudinal direction is provided on the outer periphery of the portion to be heated of the core tube. A sintering furnace. 前記炉心管自重分割負担手段が、前記炉心管の加熱を受ける部分の外周にその長手方向に所定間隔で突設された複数の鍔部と、前記炉心管の加熱を受ける部分の外周で前記各鍔部を支える炉心管自重受け手段とで構成されてい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脱水焼結用加熱炉。The core tube own weight dividing load means, the outer peripheral portion for receiving a plurality of flange portions which protrude at predetermined intervals in the longitudinal direction on the outer periphery of the portion which receives the heating of the core tube, the heating of the core tube each The furnace for dehydration sintering of a porous glass base material according to claim 1, characterized in that the furnace core tube self-weight receiving means for supporting the flange portion is configured. 前記炉心管自重受け手段が、上下に隣接する前記各鍔部の間で前記炉心管の加熱を受ける部分の外周にそれぞれ介在されて上側の前記鍔部に作用する前記炉心管の自重を負担するマッフル管により構成されてい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脱水焼結用加熱炉。The core tube self-weight receiving means bears the self-weight of the core tube acting on the upper flange portion, which is interposed on the outer periphery of the portion where the core tube is heated between the upper and lower adjacent flange portions. The heating furnace for dehydration sintering of a porous glass base material according to claim 2, wherein the heating furnace is constituted by a muffle tube. 前記炉心管自重受け手段が、前記炉心管の加熱を受ける部分の外周に沿って配置されたマッフル管と、前記炉心管の前記各鍔部に対応して前記マッフル管にそれぞれ設けられて前記各鍔部を支える複数の支え部とにより構成されてい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脱水焼結用加熱炉。The core tube self-weight receiving means is provided on the muffle tube arranged along the outer periphery of the portion to be heated of the core tube, and the muffle tube corresponding to the flanges of the core tube, The heating furnace for dehydration and sintering of a porous glass base material according to claim 2, wherein the heating furnace comprises a plurality of support portions that support the flange portion.
JP02723899A 1999-02-04 1999-02-04 Heating furnace for dehydration sintering of porous glass base material Expired - Lifetime JP3682383B2 (en)

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JP5503339B2 (en) * 2009-03-16 2014-05-28 古河電気工業株式会社 Heating furnace for dehydration sintering of porous glass base material
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