JPH0442339B2 - - Google Patents
Info
- Publication number
- JPH0442339B2 JPH0442339B2 JP33200588A JP33200588A JPH0442339B2 JP H0442339 B2 JPH0442339 B2 JP H0442339B2 JP 33200588 A JP33200588 A JP 33200588A JP 33200588 A JP33200588 A JP 33200588A JP H0442339 B2 JPH0442339 B2 JP H0442339B2
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- core tube
- furnace core
- base material
- heating
- 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.)
- Expired - Lifetime
Links
- 238000010438 heat treatment Methods 0.000 claims description 47
- 239000000463 material Substances 0.000 claims description 39
- 239000005373 porous glass Substances 0.000 claims description 32
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 31
- 229910052799 carbon Inorganic materials 0.000 claims description 30
- 238000005192 partition Methods 0.000 claims description 29
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- 239000010453 quartz Substances 0.000 claims description 9
- 238000000638 solvent extraction Methods 0.000 claims description 2
- 239000011162 core material Substances 0.000 description 65
- 239000007789 gas Substances 0.000 description 26
- 239000011521 glass Substances 0.000 description 25
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- 239000012298 atmosphere Substances 0.000 description 20
- 229910001873 dinitrogen Inorganic materials 0.000 description 16
- 239000013307 optical fiber Substances 0.000 description 10
- 238000010926 purge Methods 0.000 description 10
- 238000005245 sintering Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 235000012239 silicon dioxide Nutrition 0.000 description 5
- 238000004031 devitrification Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- 230000004580 weight loss Effects 0.000 description 2
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 229910004014 SiF4 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 1
- 235000019404 dichlorodifluoromethane Nutrition 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- ABTOQLMXBSRXSM-UHFFFAOYSA-N silicon tetrafluoride Chemical compound F[Si](F)(F)F ABTOQLMXBSRXSM-UHFFFAOYSA-N 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- SFZCNBIFKDRMGX-UHFFFAOYSA-N sulfur hexafluoride Chemical compound FS(F)(F)(F)(F)F SFZCNBIFKDRMGX-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Glass Melting And Manufacturing (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、光フアイバなどの製造に用いる高純
度石英ガラス母材の加熱炉に関し、更に詳しく
は、多孔質ガラス体を加熱処理（たとえば脱水、
ドーパンド添加、焼結）して光フアイバなどの製
造に用いる透明な高純度石英ガラス母材とする加
熱炉に関する。Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a heating furnace for a high-purity quartz glass base material used in the production of optical fibers, etc. ,
This invention relates to a heating furnace that produces a transparent high-purity quartz glass base material for use in manufacturing optical fibers and the like by adding dopants and sintering.
［従来の技術と解決すべき課題］
光フアイバ用ガラス母材を製造するために使用
する加熱炉において、従来、例えば特公昭58−
42136及び58−58299号公報並びに特開昭60−
86049号公報に示されているように、炉芯管とし
て石英ガラス管を使用することが提案されてい
る。しかしながら、石英ガラス管には高温で変化
し易いという重大な問題点が存在する。実際、
1500℃以上で加熱炉を使用した場合、炉芯管の支
持方法と炉芯管内外の差圧とを厳密に調節しない
と石英ガラス管が変形し、使用不可能となつてし
まう。また、1150℃以上で長時間使用すると、石
英ガラス管において失透（結晶化）が生じる。ガ
ラス層と失透層とは、熱膨張係数が異なるため、
生じた歪によつて、炉芯管が破壊するという問題
点も存在する。[Prior art and problems to be solved] Conventionally, in the heating furnace used to manufacture the glass base material for optical fiber, for example,
Publications 42136 and 58-58299 and JP-A-60-
As shown in Publication No. 86049, it has been proposed to use a quartz glass tube as a furnace core tube. However, a serious problem with quartz glass tubes is that they are susceptible to change at high temperatures. actual,
If a heating furnace is used at temperatures above 1500°C, the quartz glass tube will deform and become unusable unless the method of supporting the furnace core tube and the differential pressure inside and outside the furnace core tube are carefully controlled. Furthermore, when used for a long time at temperatures above 1150°C, devitrification (crystallization) occurs in the quartz glass tube. Since the glass layer and the devitrification layer have different coefficients of thermal expansion,
There is also the problem that the furnace core tube may be destroyed due to the strain that occurs.
本発明者等は、この問題点を解決するため、炉
芯管としてカーボン管が有効であることを既に見
出している（例えば、国際出願公開WO88／
06145参照）。カーボン管は、2000℃以上において
も安定であり耐熱性に優れるばかりでなく、灰分
を20ppm以下にでき高純度化が行ないやすく、ま
た、光フアイバ用ガラス母材の加熱処理に有用な
反応性ガス（Cl2、CCl4、SiF4、SF6、CCl2F2等）
と反応しないという長所をもつている。カーボン
管は加工精度が良いので、組立式にし、低コスト
化をはかることができ、さらに外面をSiCコート
やカーボンコートすることにより気密性が向上す
るのでさらに高品質の光フアイバ用ガラス母材を
得ることができる。 The present inventors have already found that a carbon tube is effective as a furnace core tube in order to solve this problem (for example, International Application Publication WO88/
06145). Carbon tubes are not only stable at temperatures above 2000℃ and have excellent heat resistance, but also have an ash content of less than 20ppm, making it easy to achieve high purity, and are also a reactive gas useful for heat treatment of glass base materials for optical fibers. ( Cl2 , CCl4 , SiF4 , SF6 , CCl2F2 , etc. )
It has the advantage of not reacting with Carbon tubes have good processing accuracy, so they can be assembled into an assembly type to reduce costs.Furthermore, by coating the outer surface with SiC or carbon, airtightness is improved, making it possible to use even higher quality glass base materials for optical fibers. Obtainable.
従来の加熱炉は、例えば、第３図のように構成
されている。この加熱炉は、中空のゾーンヒータ
により加熱処理を行なう加熱炉の一例を示したも
ので、炉体５の内側にカーボンヒータ４及び炉芯
管３が設けられている。この加熱炉は、炉体パー
ジ用窒素ガス入口６、炉芯管内雰囲気ガス入口７
及びガラス母材支持治具２を有しており、多孔質
ガラス体１が加熱炉の中に挿入されている。炉芯
管３は、上部３４、中央部３５及び下部３６から
構成され、少なくとも中央部３５はカーボンから
できており、カーボンの表面にはSiCコーテイン
グまたはカーボンコーテイングが施されているこ
ともある。 A conventional heating furnace is configured as shown in FIG. 3, for example. This heating furnace is an example of a heating furnace that performs heat treatment using a hollow zone heater, and a carbon heater 4 and a furnace core tube 3 are provided inside a furnace body 5. This heating furnace has a nitrogen gas inlet 6 for purging the furnace body, and an atmosphere gas inlet 7 in the furnace core tube.
and a glass base material support jig 2, and a porous glass body 1 is inserted into a heating furnace. The furnace core tube 3 is composed of an upper part 34, a central part 35, and a lower part 36, and at least the central part 35 is made of carbon, and the surface of the carbon may be coated with SiC or carbon.
従来の加熱炉は、第３図に示すように構成され
ているので、ガラス体を出し入れする時に、炉芯
管内に大気（作業室の雰囲気）が混入する。第４
図は、大気の混入量を測定する実験に使用するた
装置の概略図であるが、この装置は炉芯管１０
１、パージガス入口１０２、ガス採取管１０３、
酸素濃度測定装置１０４およびポンプ１０５を有
し、更に炉芯管１０１の周囲にゾーン（図示せ
ず）を有する。炉芯管１０１の内径は150mmであ
り、ガス採取管の先端は炉芯管の開口部より1m
入つた点に固定した。結果を第５図のグラフに示
す。炉芯管中に大気が混入しており、パージ窒素
ガス流量を増やしたとしても大気混入を防止する
ことは不可能であることがわかる。 Since the conventional heating furnace is constructed as shown in FIG. 3, the atmosphere (the atmosphere of the working chamber) gets mixed into the furnace core tube when the glass body is taken in and out. Fourth
The figure is a schematic diagram of the device used in the experiment to measure the amount of air mixed in.
1, purge gas inlet 102, gas sampling pipe 103,
It has an oxygen concentration measuring device 104 and a pump 105, and further has a zone (not shown) around the furnace core tube 101. The inner diameter of the furnace core tube 101 is 150 mm, and the tip of the gas sampling tube is 1 m from the opening of the furnace core tube.
Fixed at the point entered. The results are shown in the graph of FIG. It can be seen that air is mixed into the furnace core tube, and that it is impossible to prevent air mixing even if the purge nitrogen gas flow rate is increased.
このような大気の混入があると、次の様な問題
を生じる。第１に、炉芯管内が大気中にダストに
より汚染される。ダストは、SiO2、Al2O3、
Fe2O3等で構成されており、このうちAl2O3は母
材失透の、Fe2O3はロス増加の原因となる。第２
に、カーボン炉芯管内面の酸化がおこる。カーボ
ン焼成体の酸化では、バインダとして使われてい
るタール及びピツチがまず酸化することが知られ
ている。そのため、残された黒鉛粒子は脱落及び
飛散し、炉内を舞う。この粒子が、焼結したガラ
ス母材の表面に付着するので、このガラス母材か
ら作つたフアイバには、低強度部分が多く含まれ
ることになる。また当然のことながら、カーボン
炉芯管の寿命が極端に短くなる。 Such atmospheric contamination causes the following problems. First, the inside of the furnace core tube is contaminated by dust in the atmosphere. The dust is SiO 2 , Al 2 O 3 ,
It is composed of Fe 2 O 3 and the like, among which Al 2 O 3 causes devitrification of the base material, and Fe 2 O 3 causes an increase in loss. Second
Then, oxidation occurs on the inner surface of the carbon furnace core tube. It is known that when carbon fired bodies are oxidized, tar and pitch used as binders are first oxidized. Therefore, the remaining graphite particles fall off, scatter, and fly around in the furnace. Since these particles adhere to the surface of the sintered glass preform, fibers made from this glass preform will contain many low-strength portions. Also, as a matter of course, the life of the carbon furnace tube becomes extremely short.
この様な炉芯管の酸化を防ぐ方法の第１は、ガ
ラス体の出し入れ温度をカーボンが酸化しない
400℃以下に設定することである。しかしこの方
法では、炉の稼動率が大幅に低下する上に、カー
ボン炉芯管は多孔質であるので大気に一度暴露す
ると、炉芯管に大気中の酸素や水分が相当量吸着
してしまうため、酸化消耗を完全には防ぎきれな
い。 The first way to prevent oxidation of the furnace core tube is to control the temperature at which the glass body is taken in and out so that carbon does not oxidize.
The temperature should be set below 400℃. However, with this method, the operating rate of the furnace decreases significantly, and since the carbon furnace core tube is porous, once exposed to the atmosphere, a considerable amount of oxygen and moisture in the atmosphere will be adsorbed into the furnace core tube. Therefore, oxidative consumption cannot be completely prevented.
第２の方法として、炉芯管の上部に前室を設
け、多孔質ガラス母材を前室に一度収容し、ガス
置換した後多孔質ガラス母材を炉芯管内に移動す
る方法が前記国際出願公開WO88／06145に開示
されている。この前室付き炉芯管の概略断面図を
第６図に示す。 The second method is to provide a front chamber in the upper part of the furnace core tube, store the porous glass base material in the front chamber, replace the gas, and then move the porous glass base material into the furnace core tube. It is disclosed in application publication WO88/06145. A schematic cross-sectional view of this furnace core tube with a front chamber is shown in FIG.
炉体５の内側にカーボンヒータ４及びカーボン
炉芯管３５が設けられている。この加熱炉は、炉
体パージ用窒素ガス入口６、炉芯管内雰囲気ガス
入口７、ガラス母材支持治具２、前室１１、前室
ガス出口１４、前室パージガス入口１５及び間仕
切り１６を有しており、多孔質ガラス体１が加熱
炉中に挿入されている。 A carbon heater 4 and a carbon furnace core tube 35 are provided inside the furnace body 5. This heating furnace has a nitrogen gas inlet 6 for purging the furnace body, an atmospheric gas inlet 7 in the furnace core tube, a glass base material support jig 2, a front chamber 11, a front chamber gas outlet 14, a front chamber purge gas inlet 15, and a partition 16. A porous glass body 1 is inserted into a heating furnace.
第６図の焼結炉へ多孔質ガラス体を挿入するに
は、次の様にする。 To insert the porous glass body into the sintering furnace of FIG. 6, proceed as follows.
１ 回転・上下動可能なチヤツクに多孔質ガラス
体１を支持棒２を介して取り付ける。1. A porous glass body 1 is attached via a support rod 2 to a chuck that can be rotated and moved up and down.
２ 前室１１の上ブタを開け、多孔質ガラス体１
を前室１１内に降下させる。2 Open the top lid of the front chamber 11 and remove the porous glass body 1.
is lowered into the front chamber 11.
３ 上ブタを閉じ、前室内を不活性ガス（N2又
はHe等）で置換する。3 Close the top lid and replace the inside of the front chamber with inert gas (N 2 or He, etc.).
４ 前室１１と加熱雰囲気を隔てる間仕切り１６
を開け、多孔質ガラス体１をあらかじめ加熱処
理温度に保たれた加熱雰囲気へ導入する。4 Partition 16 separating the front chamber 11 and the heating atmosphere
The chamber is opened and the porous glass body 1 is introduced into a heated atmosphere that has been maintained at a heat treatment temperature in advance.
５ 間仕切り１６を閉める。5 Close the partition 16.
また、この加熱炉から母材を取り出すには、次
の様にする。 Further, to take out the base material from this heating furnace, proceed as follows.
１ 間仕切り１６を開ける。1 Open the partition 16.
２ 加熱処理が終わつた母材１を加熱雰囲気から
前室１１へ引上げる。その際、加熱雰囲気の温
度は、必ずしも下げる必要はない。2. The base material 1 that has been subjected to the heat treatment is pulled up from the heating atmosphere to the front chamber 11. At that time, the temperature of the heating atmosphere does not necessarily need to be lowered.
３ 間仕切り１６を閉じる。3 Close the partition 16.
４ 前室１１の上ブタを開け、母材１を取り出
す。4 Open the top lid of the front chamber 11 and take out the base material 1.
この装置は酸化を防止するという機能において
は優れた効果を示すが、装置全長が長くなりす
ぎ、また間仕切り１６が複雑な構造となるという
欠点があつた。第７図は、多孔質ガラス母材全長
800mm、種棒長200mmの場合の装置全長の例であ
る。この場合、チヤツク下端の位置で6760mm必要
であり、設計や作業上必要なスペースを見込むと
8000mm近くになつてしまう。 Although this device has an excellent effect in preventing oxidation, it has the disadvantage that the overall length of the device is too long and the partition 16 has a complicated structure. Figure 7 shows the total length of the porous glass base material.
This is an example of the total length of the device when the seed rod length is 800 mm and the seed rod length is 200 mm. In this case, 6760 mm is required at the bottom end of the chuck, and considering the space required for design and work.
It will be close to 8000mm.
また間仕切り１６は多孔質ガラス母材支持治具
が貫通している時としていない時の両方の場合に
対応しなければならないので、保持棒部を切欠い
た２つ割の部品と支持治具貫通部を塞ぐ部品と計
３個の部品で前室と炉芯管を間仕切る必要があつ
た。 In addition, the partition 16 must be compatible with both cases when the porous glass base material support jig penetrates and when it does not, so it must be divided into two parts with the holding rod section cut out and the support jig penetration section. It was necessary to partition the front chamber and the furnace core tube with a total of three parts, including one to block the front chamber.
［課題を解決するための手段］
本発明は、このような従来の加熱炉の欠点に鑑
みなされたもので、その要旨は、中空のゾーンヒ
ータを有する炉体と、この炉体を貫通する炉芯管
とを有し、高純度石英多孔質ガラス母材を該炉芯
管内上下方向に通過させて加熱処理する為の加熱
炉において、該加熱炉が炉体の上部に突出してい
る部分において炉芯管内空間を上下に仕切る手段
を有することを特徴とする高純度石英母材製造用
加熱炉に関する。[Means for Solving the Problems] The present invention was made in view of the drawbacks of such conventional heating furnaces, and the gist thereof is to provide a furnace body having a hollow zone heater, and a furnace penetrating the furnace body. In a heating furnace that has a core tube and heat-treats a high-purity quartz porous glass base material by passing it in the vertical direction inside the furnace core tube, a furnace The present invention relates to a heating furnace for producing a high-purity quartz base material, which is characterized by having means for partitioning the inner space of a core tube into upper and lower parts.
本発明を、添付図面を参照して、具体的に説明
する。 The present invention will be specifically described with reference to the accompanying drawings.
第１図は本発明の加熱炉の一具体例である。第
１図において、炉体５の内側にカーボンヒータ４
及び炉芯管３が設けられている。炉芯管３は高純
度カーボンの表面にSiCコーテイング又はカーボ
ンコーテイングを施した中央部３５、下部３６と
石英製の上部３４及び上蓋３７からなつている。
この加熱炉には、炉体パージ用窒素ガス入口６、
炉芯管内雰囲気ガス入口７、ガラス母材支持具
２、炉芯管雰囲気ガス排気口２１、炉芯管上部ガ
ス置換用窒素ガス入口２２、ガス通過用の小穴２
４を持つ石英製仕切り２３を有しており、多孔質
ガラス母材１が炉芯管中に挿入される。仕切り２
３は、外部から石英製仕切移動治具２６で開閉で
きる様になつている。仕切り２３を閉じた状態
で、ガスが炉芯管の下部から上部へわずかなすき
間を通つて流れる構造になつていればその手段は
小穴２４でなくても良い。また仕切り２３より上
の炉芯管内空間にガラス母材１が存在する時に
100℃ないし800℃に加熱することができるヒータ
２５が取り付けられる場合がある。このヒータは
抵抗発熱体でもよいし、赤外線加熱ランプでもよ
い。ガラス母材１は、仕切り２３の上方空間に完
全に収容できる必要があるが、仕切２３はヒータ
４より上にあれば、位置はどこでも良く、図示の
位置に限定されるものではない。一般には炉体５
の上部におかれる。 FIG. 1 shows a specific example of the heating furnace of the present invention. In FIG. 1, a carbon heater 4 is installed inside the furnace body 5.
and a furnace core tube 3 are provided. The furnace core tube 3 consists of a central part 35 and a lower part 36 made of high-purity carbon whose surface is coated with SiC or carbon, and an upper part 34 and a top cover 37 made of quartz.
This heating furnace includes a nitrogen gas inlet 6 for purging the furnace body,
Furnace core tube internal atmosphere gas inlet 7, glass base material support 2, furnace core tube atmosphere gas exhaust port 21, furnace core tube upper gas replacement nitrogen gas inlet 22, small hole 2 for gas passage
The porous glass preform 1 is inserted into the furnace core tube. Partition 2
3 can be opened and closed from the outside using a quartz partition moving jig 26. The means need not be the small holes 24 as long as the gas flows from the bottom to the top of the furnace core tube through a slight gap when the partition 23 is closed. Also, when the glass base material 1 is present in the space inside the furnace core tube above the partition 23,
A heater 25 capable of heating to 100°C to 800°C may be attached. This heater may be a resistive heating element or an infrared heating lamp. The glass base material 1 needs to be completely accommodated in the space above the partition 23, but the partition 23 may be positioned anywhere as long as it is above the heater 4, and is not limited to the illustrated position. Generally, the furnace body 5
placed on top of the
第１図の焼結炉へ多孔質ガラス体を挿入するに
は次の様にする。 The porous glass body is inserted into the sintering furnace of FIG. 1 as follows.
１ 回転・上下可能なチヤツクに多孔質ガラス体
１を支持棒２を介して取り付ける。1. A porous glass body 1 is attached via a support rod 2 to a chuck that can be rotated and moved up and down.
２ 炉芯管３の上蓋３７を開け、多孔質ガラス体
を炉芯管３の上部３４内に降下させる。この
際、仕切２３は閉じられており、炉芯管雰囲気
ガス入口７よりパージ用窒素ガスが炉芯管３内
に導入され、仕切り２３の小穴２４を通じて炉
芯管上部３４の空間に流入している。従つて、
炉芯管の中下部の空間は窒素ガス雰囲気であ
り、上蓋３５を開いても仕切り２３が存在する
ので大気を巻きこむことはない。2 Open the upper cover 37 of the furnace core tube 3 and lower the porous glass body into the upper part 34 of the furnace core tube 3. At this time, the partition 23 is closed, and nitrogen gas for purging is introduced into the furnace core tube 3 from the furnace tube atmospheric gas inlet 7, and flows into the space in the upper part of the furnace core tube 34 through the small hole 24 of the partition 23. There is. Therefore,
The space in the middle and lower part of the furnace core tube is in a nitrogen gas atmosphere, and even if the upper lid 35 is opened, the presence of the partition 23 prevents atmospheric air from being drawn in.
３ 上蓋３７を閉め、炉芯管上部窒素パージ口２
２から窒素ガスを導入し、炉芯管上部３４内の
空間を窒素ガスに置換する。この時ヒータ２５
により多孔質ガラス体１を加熱すると、多孔質
ガラス体には吸着していたガスがより効率的に
放出される。3 Close the upper lid 37 and open the upper nitrogen purge port 2 of the furnace core tube.
Nitrogen gas is introduced from 2 to replace the space in the upper part 34 of the furnace core tube with nitrogen gas. At this time, heater 25
When the porous glass body 1 is heated, the gas adsorbed in the porous glass body is released more efficiently.
４ 仕切り２３を開け、多孔質ガラス体を処理開
始位置まで（例えばヒータ上端に多孔質ガラス
体下端が来る位置まで）下げる。上部パージ用
ガス入口２２からのガス供給を停止し、ヒータ
２５も切つて、多孔質ガラス体の焼結処理を開
始する。4 Open the partition 23 and lower the porous glass body to the processing start position (for example, to the position where the bottom end of the porous glass body is at the top end of the heater). Gas supply from the upper purge gas inlet 22 is stopped, the heater 25 is also turned off, and the sintering process of the porous glass body is started.
また第１図の焼結炉から母材を取り出すには次
の様にする。 Further, the base material is taken out from the sintering furnace shown in FIG. 1 in the following manner.
１ 処理を終わつた母材を仕切り２３の上まで引
き上げる。炉芯管雰囲気ガス導入口７から窒素
ガスを導入しつつ、雰囲気ガスを排気口２１か
ら排気し、炉芯管３内を完全に窒素雰囲気に置
換する。1. Pull the treated base material up to the top of the partition 23. While nitrogen gas is introduced through the furnace core tube atmosphere gas inlet 7, the atmosphere gas is exhausted through the exhaust port 21 to completely replace the inside of the furnace core tube 3 with a nitrogen atmosphere.
２ 仕切２３を閉じる。導入口７からの窒素ガス
導入は流量を減らしてもよいが、小穴２４を通
して上部のガスを中下部に巻き込まない様に流
し続ける。2 Close the partition 23. The flow rate of nitrogen gas introduced from the inlet 7 may be reduced, but the upper gas continues to flow through the small hole 24 so as not to get caught up in the middle and lower parts.
３ 上蓋３７を開き、母材１を取り出す。3 Open the top lid 37 and take out the base material 1.
［実施例］ 以下に本発明の実施例を示す。[Example] Examples of the present invention are shown below.
実施例 １
第１図に相当する多孔質ガラス母材全長800mm、
種棒長200mmの場合に適した装置を、本発明に従
つて設計した。最低必要な寸法は、第２図の様
に、チヤツク下端の位置で5560mmであつた。設計
上必要なスペースや作業上必要なスペースも含め
て実際に設計した装置の全高は6800mmであつた。
第６図の同じ大きさの母材を処理する装置より約
1.2m低くてよいことがわかつた。Example 1 Porous glass base material total length 800 mm corresponding to Fig. 1,
A device suitable for a seed rod length of 200 mm was designed according to the invention. The minimum required dimension was 5560mm at the bottom of the chuck, as shown in Figure 2. The total height of the actually designed equipment, including the space required for design and work, was 6800mm.
Approx.
I found out that 1.2m lower is fine.
実施例 ２ 第１図に示す加熱炉を使用した。Example 2 A heating furnace shown in FIG. 1 was used.
多孔質ガラス体を炉芯管上部に入れ、炉芯管の
上蓋を閉じ、上部内に窒素ガスを10／分で10分
間流し、また下部からも窒素ガスを10／分で流
し続けた。炉芯管の中央部及び下部として、それ
ぞれ外表面にガス不透過性カーボン膜またはSiC
膜をコーテイングした高純度カーボン製管を用い
た。 The porous glass body was placed in the upper part of the furnace core tube, the upper lid of the furnace core tube was closed, nitrogen gas was flowed into the upper part at 10/min for 10 minutes, and nitrogen gas was continued to flow from the lower part at 10/min. Gas-impermeable carbon membrane or SiC is applied to the outer surface of the central and lower parts of the furnace core tube, respectively.
A high-purity carbon tube coated with a membrane was used.
仕切りを開け、透明な光フアイバ用ガラス母材
を製造した。なお、脱水および焼結の条件は以下
の通りであつた。 The partition was opened and a transparent glass base material for optical fiber was manufactured. The conditions for dehydration and sintering were as follows.
脱 水
He 10／分
Cl2 500c.c.／分
トラバース速度 ８mm／分
温 度 1100℃
焼 結
He 10／分
トラバース速度 ３mm／分
温 度 1650℃
このガラス母材をコア材として用い、クラツド
としては別途作成したふつ素を添加したガラスパ
イプを用い、これらを抵抗炉により一体化し、さ
らに外径調整のための外付け法によりガラス層を
付けた光フアイバ母材を線引きし、純シリカコア
シングルモード光フアイバを作つたところ、
0.18dB／Km（光波長1.55μmにおいて）と低損失
であつた。 Dehydrated He 10/min Cl 2 500c.c./min Traverse speed 8mm/min Temperature 1100℃ Sintered He 10/min Traverse speed 3mm/min Temperature 1650℃ This glass base material is used as a core material and as a cladding. Using glass pipes doped with fluorine, which were prepared separately, these were integrated in a resistance furnace, and an optical fiber base material with a glass layer was drawn using an external attachment method to adjust the outer diameter, resulting in a pure silica core single. When I made a mode optical fiber,
The loss was as low as 0.18 dB/Km (at an optical wavelength of 1.55 μm).
実施例 ３
実施例２と同様の方法で多孔質ガラス体の焼結
処理を40回行なつた。この間のカーボン炉芯管の
減量は14ｇ（加熱部で35μmの酸化消耗に相当）
であつた。この量はカーボン炉芯管が２年程度使
用可能であることを示している。Example 3 A porous glass body was sintered 40 times in the same manner as in Example 2. The weight loss of the carbon furnace core tube during this time was 14g (equivalent to oxidation consumption of 35μm in the heating section)
It was hot. This amount indicates that the carbon furnace core tube can be used for about two years.
比較例 １ 第６図に示す従来技術の加熱炉を使用した。Comparative example 1 A conventional heating furnace shown in FIG. 6 was used.
多孔質ガラス体を前室に入れ、前室の上ブタを
閉じ、前室内に窒素ガスを10／分で10分間流
し、前室内を窒素ガスで置換した。その後、間仕
切りを開け、多孔質ガラス体を前室から炉芯管内
へ移動させ、間仕切りを閉めた後加熱処理を行な
い、透明な光フアイバ用ガラス母材を製造した。
母材の取り出し時には先ず間仕切りを開け、ガラ
ス母材を前室に移動させた後に間仕切りを閉め、
その後上ブタを開けガラス母材を取り出した。こ
のガラス母材をコア材として光フアイバを作つた
ところ、0.18dB／Km（光波長1.55μmに於いて）
と低損失であつた。 The porous glass body was placed in the front chamber, the top lid of the front chamber was closed, and nitrogen gas was flowed into the front chamber at 10/min for 10 minutes to replace the inside of the front chamber with nitrogen gas. Thereafter, the partition was opened, the porous glass body was moved from the front chamber into the furnace core tube, and after the partition was closed, heat treatment was performed to produce a transparent glass preform for optical fiber.
When taking out the base material, first open the partition, move the glass base material to the front chamber, close the partition,
After that, the upper lid was opened and the glass base material was taken out. When an optical fiber was made using this glass base material as a core material, the result was 0.18 dB/Km (at a light wavelength of 1.55 μm)
The loss was low.
比較例 ２
比較例１と同様の方法で、多孔質ガラス体の加
熱処理を40回行なつた。この間のカーボン炉芯管
の減量は20ｇ（表面より50μmの酸化消耗に相当）
であつた。この量は、カーボン炉芯管が1.5年程
度使用可能であることを示している。Comparative Example 2 A porous glass body was heated 40 times in the same manner as in Comparative Example 1. During this time, the weight loss of the carbon furnace core tube was 20g (equivalent to oxidation consumption of 50μm from the surface).
It was hot. This amount indicates that the carbon furnace tube can be used for about 1.5 years.
実施例３と比較例２の炉芯管の消耗量の差は、
実施例３では炉芯管下部からも窒素の供給があつ
たこと、比較例１の方が間仕切が複雑で置換部容
積が広がつたこと、実施例３の方が多孔質ガラス
体が置換時ヒータに近い位置にあるため多孔質ガ
ラス体からのガス放出が進んだことの３点の複合
作用の結果であると考えられる。 The difference in the amount of wear of the furnace core tube between Example 3 and Comparative Example 2 is as follows:
In Example 3, nitrogen was also supplied from the lower part of the furnace core tube, in Comparative Example 1, the partition was more complicated and the volume of the replacement section was larger, and in Example 3, the porous glass body was larger during replacement. This is considered to be the result of a combination of three factors: gas release from the porous glass body progressed because it was located close to the heater.
実施例 ４
実施例２と同条件で置換時間を20分間に増や
し、置換中多孔質ガラス体を800Wの赤外線ラン
プ灯で加熱した。置換中多孔質ガラス体が均一に
加熱されるように回転させた。40本の焼結処理後
のカーボン炉芯管の消費量は６ｇ（表面より
15μmの消耗）であつた。この量はカーボン炉芯
管が５年程度使用可能であることを示している。Example 4 The replacement time was increased to 20 minutes under the same conditions as in Example 2, and the porous glass body was heated with an 800W infrared lamp during the replacement. During substitution, the porous glass body was rotated to ensure uniform heating. The consumption of 40 carbon furnace core tubes after sintering is 6g (from the surface).
15 μm of wear). This amount indicates that the carbon furnace tube can be used for about 5 years.
［発明の効果］ 本発明の効果は、以下の通りである。[Effect of the invention] The effects of the present invention are as follows.
加熱雰囲気への大気（作業室の雰囲気）の混入
がなくなり、炉芯管内の不純物による汚染がなく
なる。それ故、ガラス母材の失透が防げると共
に、透明度が向上する。 Air (work room atmosphere) is no longer mixed into the heating atmosphere, and contamination by impurities in the furnace core tube is eliminated. Therefore, devitrification of the glass base material can be prevented and transparency can be improved.
炉芯管がカーボンから製造されている場合、カ
ーボンの酸化消耗が抑えられ、炉芯管の寿命が伸
びる。また同様の目的で前室を設けた従来技術の
加熱炉式と比較して、構造、機構が単純であるに
も拘わらず同等かそれ以上の効果があり、かつ装
置全高も低くてすむ。 When the furnace core tube is manufactured from carbon, the oxidative consumption of carbon is suppressed and the life of the furnace core tube is extended. Furthermore, compared to the conventional heating furnace type which has a front chamber for the same purpose, although the structure and mechanism are simple, it has the same or better effect, and the overall height of the device can be reduced.
ガラス母材の出し入れ時に、炉体を降温させる
ことがないので、炉の稼動率が高い。 Since the temperature of the furnace body is not lowered when the glass base material is taken in and out, the furnace operation rate is high.
第１図は、本発明の加熱炉の一具体例の概略断
面図、第２図は、本発明の加熱炉に必要な全高を
示す模式図、第３図は、従来技術の加熱炉の１例
の断面図、第４図は、炉芯管への大気の混入量を
測定する装置の模式図、第５図は、第４図の装置
で測定した従来技術の加熱炉の炉芯管への大気混
入量を示すグラフ、第６図は、従来技術の加熱炉
の他の例の断面図、および第７図は、第６図の加
熱炉の全高を示す模視図である。
１…ガラス母材、２…ガラス母材用支持治具、
３…炉芯管、４…カーボンヒータ、５…炉体、６
…炉体パージ用窒素ガス入口、７…炉芯管内雰囲
気ガス入口、２１…炉芯管雰囲気ガス排出口、２
２…炉芯管上部ガス置換用雰囲気ガス入口、２３
…仕切り、２４…小穴、２５…ヒータ。
FIG. 1 is a schematic sectional view of a specific example of the heating furnace of the present invention, FIG. 2 is a schematic diagram showing the total height required for the heating furnace of the present invention, and FIG. 3 is a schematic cross-sectional view of a specific example of the heating furnace of the present invention. 4 is a schematic diagram of a device for measuring the amount of air entering the furnace core tube, and FIG. 5 is a cross-sectional view of the furnace core tube of a conventional heating furnace measured with the device shown in FIG. 4. FIG. 6 is a cross-sectional view of another example of the heating furnace of the prior art, and FIG. 7 is a schematic diagram showing the total height of the heating furnace of FIG. 6. 1...Glass base material, 2...Support jig for glass base material,
3...Furnace core tube, 4...Carbon heater, 5...Furnace body, 6
...Nitrogen gas inlet for furnace body purge, 7...Atmosphere gas inlet in furnace core tube, 21...Atmosphere gas outlet in furnace core tube, 2
2...Atmosphere gas inlet for upper gas replacement of the furnace core tube, 23
...Partition, 24...Small hole, 25...Heater.
Claims (1)
体を貫通する炉芯管とを有し、高純度石英多孔質
ガラス母材を該炉芯管内上下方向に通過させて加
熱処理する為の加熱炉において、該炉芯管が炉体
の上部に突出している部分において炉芯管内空間
を上下に仕切る手段を有することを特徴とする高
純度石英母材製造用加熱炉。 ２ 仕切られた炉芯管の上部空間は、石英多孔質
ガラス母材を完全に収納できる容積を持つ特許請
求第１項記載の加熱炉。 ３ 仕切り手段より下部にある炉芯管部分が高純
度カーボンからなる特許請求第１項記載の加熱
炉。 ４ 仕切り手段より上部にある炉芯管部分が石英
からなる特許請求第１項記載の加熱炉。 ５ 仕切られた炉芯管の上部空間の周囲に熱源を
有する特許請求第１項記載の加熱炉。[Claims] 1. A furnace having a furnace body having a hollow zone heater and a furnace core tube passing through the furnace body, and having a high purity quartz porous glass base material passed in the vertical direction inside the furnace core tube. A heating furnace for producing a high-purity quartz base material, characterized in that the heating furnace for producing a high-purity quartz base material is provided with means for partitioning the inner space of the furnace core tube into upper and lower parts at a portion where the furnace core tube projects above the furnace body. 2. The heating furnace according to claim 1, wherein the upper space of the partitioned furnace core tube has a volume that can completely accommodate the quartz porous glass base material. 3. The heating furnace according to claim 1, wherein the furnace core tube portion located below the partition means is made of high-purity carbon. 4. The heating furnace according to claim 1, wherein the furnace core tube portion located above the partition means is made of quartz. 5. The heating furnace according to claim 1, which has a heat source around the upper space of the partitioned furnace core tube.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63332005A JPH02180728A (en) | 1988-12-29 | 1988-12-29 | Heating furnace for producing high-purity quartz preform |
| AU46870/89A AU626362B2 (en) | 1988-12-29 | 1989-12-19 | Furnace for producing high purity quartz glass preform |
| GB8928691A GB2226628B (en) | 1988-12-29 | 1989-12-20 | Furnace |
| US07/459,299 US5032079A (en) | 1988-12-29 | 1989-12-29 | Furnace for producing high purity quartz glass preform |
| KR898920189A KR920001386B1 (en) | 1988-12-29 | 1989-12-29 | Heating furnace for producing high-purity quartz preform |
| EP90106551A EP0450124B1 (en) | 1988-12-29 | 1990-04-05 | Furnace for producing high purity quartz glass preform |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63332005A JPH02180728A (en) | 1988-12-29 | 1988-12-29 | Heating furnace for producing high-purity quartz preform |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02180728A JPH02180728A (en) | 1990-07-13 |
| JPH0442339B2 true JPH0442339B2 (en) | 1992-07-13 |
Family
ID=18250074
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63332005A Granted JPH02180728A (en) | 1988-12-29 | 1988-12-29 | Heating furnace for producing high-purity quartz preform |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02180728A (en) |
-
1988
- 1988-12-29 JP JP63332005A patent/JPH02180728A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02180728A (en) | 1990-07-13 |
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