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WO2002008129A1 - Method for the vitrification of a porous soot body - Google Patents

Method for the vitrification of a porous soot body Download PDF

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Publication number
WO2002008129A1
WO2002008129A1 PCT/EP2001/008436 EP0108436W WO0208129A1 WO 2002008129 A1 WO2002008129 A1 WO 2002008129A1 EP 0108436 W EP0108436 W EP 0108436W WO 0208129 A1 WO0208129 A1 WO 0208129A1
Authority
WO
WIPO (PCT)
Prior art keywords
soot body
soot
heating zone
glazing
porous
Prior art date
Application number
PCT/EP2001/008436
Other languages
German (de)
French (fr)
Inventor
Gerhart Vilsmeier
Horst Heidsieck
Original Assignee
Heraeus Tenevo Ag
Shin-Etsu Quartz Products Co., 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
Priority claimed from DE10041467A external-priority patent/DE10041467C1/en
Application filed by Heraeus Tenevo Ag, Shin-Etsu Quartz Products Co., Ltd. filed Critical Heraeus Tenevo Ag
Priority to JP2002513830A priority Critical patent/JP2004525842A/en
Priority to KR10-2003-7001032A priority patent/KR20030051601A/en
Publication of WO2002008129A1 publication Critical patent/WO2002008129A1/en

Links

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]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • C03B37/0146—Furnaces therefor, e.g. muffle tubes, furnace linings
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00—Other methods of shaping glass
    • C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
    • C03B19/1453—Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00—Other methods of shaping glass
    • C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
    • C03B19/1469—Means for changing or stabilising the shape or form of the shaped article or deposit
    • 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]
    • C03B37/01466—Means for changing or stabilising the diameter or form of tubes or rods
    • 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
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/47—Shaping the preform draw bulb before or during drawing

Definitions

  • the invention relates to a method for vitrifying a porous soot body made of silicon dioxide, with a soot body which is held in a vertical orientation by means of a holding device and is continuously fed to a heating zone, the soot body being surrounded by a mold at least from the entry into the heating zone.
  • the holder consists of a bracket formed from platinum wires, on which the hollow cylindrical soot body is suspended.
  • the hollow cylinder wall has two horizontally extending through holes in its upper region, through which the platinum wires are guided.
  • the soot body is continuously fed to a vertically oriented sintering furnace. The soot body softens in a softening zone.
  • the softening zone begins at the lower end of the soot body. With the Lowering the soot body into the sintering furnace continuously moves the softening zone in the soot body upwards. The weight of the already sintered part of the soot body hanging from the softening zone increases continuously. Due to the low viscosity in the softening zone, the soot body lengthens when it is lowered under its own weight. The method is therefore particularly unsuitable for sintering large-volume and heavy soot bodies and it leads to relatively imprecise quartz glass bodies in terms of their dimensions, which have to be reworked, for example, by grinding.
  • volume contraction of the soot body is determined on the basis of its sintering activity, but this does not lead to sufficiently exact dimensions or deformations (so-called banana shape). It is therefore also necessary with this method to rework the glazed quartz glass body by grinding.
  • a method in which a rod-shaped soot body made of silicon dioxide is glazed within a mold is known from DE 3521 119 A1.
  • the shape itself is also made of quartz glass and forms the cladding glass of a preform for optical fibers.
  • the cladding glass shrinks inextricably onto the glazing soot body.
  • This procedure is solely aimed at producing an optical fiber preform.
  • the permanent connection between the cladding glass and the soot body to be glazed inside is useful for this application.
  • a general shaping glazing of soot bodies made of silicon dioxide by means of quartz glass molds is disadvantageous, since after the glazing the outer area of the obtained
  • Quartz glass body which corresponds to the original shape, for example, would have to be removed again by complex grinding. Furthermore, it cannot be ruled out that in the cross section of the quartz glass body obtained at the transition area between the original soot body and the quartz glass shape, undesirable jumps in the glass properties can be recorded.
  • this object is achieved according to the invention in that the soot body within the
  • Heating zone is heated to a temperature at which it softens to the extent that it takes on the lateral dimensions of the mold to form a glazed soot body, and that the glazed soot body is detached from the mold.
  • the soot body to be sintered is essentially dimensionally stable at room temperature. This means that it can be set up or hung up vertically without plastically deforming under its own weight.
  • the silicon dioxide soot softens in the heating zone. Its viscosity decreases, so that the soot body deforms under the forces acting on the softening zone. In addition to gravity, it also works Deformation forces due to a volume contraction on the soot body.
  • the soot body has a density of only approx. 30% of the solid quartz glass. Since the sintering or vitrification takes place continuously, the softening zone moves from one end of the soot body to the opposite end.
  • the soot body is continuously introduced into the heating zone of a sintering or glazing furnace and is thereby heated to a temperature at which the soot body softens to such an extent that it flows out into a shape surrounding it or fills the hollow dimensions of a shape surrounding it.
  • the shape itself can either be carried with the soot body before the soot body is immersed in the heating zone or it is located within the sintering furnace and only takes up the soot body there.
  • the shape is such that the softening soot body or the glazed quartz glass body does not adhere to it and can therefore be removed from it without destroying it.
  • the shape can expediently consist of several parts that can be assembled.
  • the method according to the invention enables soot bodies to be vitrified continuously with relatively precise predetermination of the final dimensions of the quartz glass body to be obtained. Distortion or deformation of the glazing soot body, as can be observed in the method according to the prior art, are excluded with the method according to the invention.
  • the method according to the invention has proven particularly useful when a holding device acts at least on the upper end of the soot body to be glazed, a cylindrical graphite rod which is guided through the longitudinal bore of the hollow cylindrical soot body being advantageous as the holding device, and which helps stabilize the soot body.
  • the holding device can also support the soot body at the base.
  • the holding device is moved in the vertical direction with a controllable or controllable movement speed by means of a movement unit such that the soot body is fed to the heating zone in accordance with its length contraction.
  • the holding device is connected to a movement unit.
  • the vertical movement of the holding device with the soot body can be controlled or regulated in accordance with the contraction in length of the soot body during the glazing. This means that the feed rate into the heating zone can be varied and adapted to the volume and length contraction.
  • the porous soot body is expediently produced by the flame hydrolysis process.
  • the Si0 2 particles resulting from flame hydrolysis are collected on a support and form the porous soot body. If the carrier is, for example, a cylindrical rod which is removed again after the separation, a hollow cylindrical soot body is obtained.
  • a hollow cylindrical soot body has the advantage that, as long as the cavity is deliberately maintained during glazing, a quartz glass rod can be inserted into the cavity if necessary, which forms the core for a preform from which optical fibers can be drawn.
  • the Si0 2 -Mate ⁇ ' al from such a core rod and from the jacket surrounding the core rod can differ in terms of dopants.
  • the temperature for the glazing is preferably carried out in two steps with a pre-sintering at approximately 1300 to 1350 ° C. and a final glazing at approximately 1700 to 1750 ° C.
  • a material that is stable up to 1800 ° C. is expedient. Ceramic materials are suitable for such applications. Graphite or silicon carbide has proven particularly useful.
  • the molding material can be gas-permeable in order to enable or improve the application of gas or also the removal of gas during or before the glazing. Different grades of graphite can be used, carbon-fiber-reinforced graphite (CFC) being particularly suitable.
  • CFC carbon-fiber-reinforced graphite
  • refractory metals preferably molybdenum or platinum, are also suitable.
  • a halogen-containing gas is applied to expel water from the soot.
  • Chlorine gas has proven itself as a halogen-containing gas.
  • This treatment step is also called chlorination.
  • the chlorination can take place as a separate process step before the soot body is vitrified, or if the soot body is already in the glazing furnace (inside or outside the mold), but before the soot sinters, i.e. in a temperature range between 800 ° C and about 1200 ° C.
  • soot body is glazed under a vacuum or protective gas atmosphere, since this prevents or largely reduces oxidation of the graphite or molybdenum mold material, and also ensures high quality in terms of purity for the soot body to be glazed.
  • a vacuum or protective gas atmosphere Argon, Helium or nitrogen proven.
  • a helium atmosphere is particularly preferred because of the relatively good heat transfer.
  • FIGS. 1 and 2 show a schematic illustration of simple glazing devices for the method according to the invention.
  • the device according to FIG. 1 has an oven 1 with a vertical, cylindrical protective tube, which is surrounded on the outside by heating elements 2.
  • the heating elements 2 generate a heating zone 2a in the furnace (indicated schematically in FIGS. 1 and 2 by horizontal, dashed boundary lines within the furnace protection tube).
  • the hollow cylindrical soot body 3 to be glazed is now - after chlorination (chlorine gas flow 36 l / h) at 1000 ° C. - in the graphite mold 4, with a holding rod 5 being inserted into the longitudinal bore of the soot body 3 to stabilize the soot body 3.
  • the holding rod 5 engages with a plate 6 at the upper end of the soot body 3 and is additionally supported on the bottom of the graphite mold 4.
  • the graphite mold 4 is slowly fed into the furnace 1 from above by means of a movement unit 7, so that the lower part of the soot body 3 first reaches the heating zone 2a and is glazed there. To ensure complete glazing, the temperature in the hottest area of heating zone 2a is set to approximately 1700 ° C. A vacuum of 0.1 mbar prevails in the furnace 1. When the graphite mold 4 is lowered further with the soot body 3, the glazed area of the soot body 3 moves further upwards until a completely glazed quartz glass body has formed. Escaping residual gases can be discharged upwards through the porous part of the soot body 3.
  • the slowly glazing soot body 3 assumes the hollow dimensions of the shape 4 surrounding it.
  • Typical dimensions of the soot body 3 before glazing are in the range from 400 to 450 mm for the outer diameter and with a length of 2.5 to 3.0 meters.
  • the diameter of the longitudinal bore or the holding rod 5 is approximately 50 to 80 mm.
  • an average feed speed of the movement unit 7 of approximately 3 mm / min (downwards)
  • a glazed quartz glass hollow cylinder with an outer diameter of 150 to 200 mm (diameter of the bore approximately 50 to 80 mm) and a length of 2 meters can be obtained.
  • FIG. 2 shows a device for the method according to the invention, which comprises integrated chlorination and allows the end dimensions of the glazed quartz glass body to differ more than the geometry of the soot body 3.
  • the soot body 3 to be glazed is located in an upper part of a gas-permeable graphite mold 4a, which is initially let into an upper but colder area of an oven 1 as explained with FIG. 1 and is charged with chlorine gas.
  • the temperature during the chlorination is about 950 ° C at 10 vol% Cl 2 in helium (Cl 2 / He).
  • the gas is fed into the furnace 1 from below.
  • the gas flows through the soot body 3 and is led outwards again through the graphite form 4a which is gas-permeable at least in the upper region.
  • the soot body 3, together with the mold 4a is slowly lowered further into higher temperature ranges, so that a pre-sintering phase at
  • the graphite mold 4a is removed from the quartz glass body. It is not necessary to rework the quartz glass body.

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

Abstract

In a conventional method for the vitrification of a porous soot body of silicon dioxide, the soot body is retained in the vertical direction by means of a retaining device and continuously fed into a heating zone. Further to the above the soot body, at least from the entry to the heating zone onwards, is surrounded by a mould. According to the invention, in order to achieve an economical method, suitable for the vitrification of large volume porous soot bodies of silicon dioxide, whereby the refinishing steps for optimising the external dimensions of the obtained quartz glass body can be minimised, the soot body (3) is heated to a temperature, within the heating zone (2a), whereby said body is softened to the extent that on forming the vitrified soot body (3), said body adopts the lateral dimensions of the mould (4; 4a) and that the vitrified soot body (3) is released from the mould (4; 4a).

Description

Verfahren zum Verglasen von porösen Sootkörpern Process for glazing porous soot bodies
Die Erfindung betrifft ein Verfahren zum Verglasen eines porösen Sootkörpers aus Siliziumdioxid, mit einem Sootkörper, der mittels einer Haltevorrichtung in vertikaler Ausrichtung gehalten und kontinuierlich einer Erhitzungszone zugeführt wird, wobei der Sootkörper zumindest ab dem Eintritt in die Erhitzungszone von einer Form umgeben ist.The invention relates to a method for vitrifying a porous soot body made of silicon dioxide, with a soot body which is held in a vertical orientation by means of a holding device and is continuously fed to a heating zone, the soot body being surrounded by a mold at least from the entry into the heating zone.
Die Herstellung von Vorformen für optische Fasern und die von Vorformen für Ofenbauteile für die Halbleitertechnik erfolgt häufig über ein Zwischenprodukt, einem porösen Sootkörper aus Siliziumdioxid. Diese sogenannten „Sootkörper" sind mechanisch instabil und daher insbesondere bei großen Volumen und hohem Gewicht nur schwer handhabbar. Für die Einsatzzwecke in der optischen Nachrichtentechnik und in der Halbleitertechnik werden höchste Anforderungen an die Reinheit der Sootkörper gestellt, so dass derenThe production of preforms for optical fibers and preforms for furnace components for semiconductor technology often takes place via an intermediate product, a porous soot body made of silicon dioxide. These so-called "soot bodies" are mechanically unstable and are therefore difficult to handle, particularly in the case of large volumes and high weight. For the purposes of use in optical communications technology and in semiconductor technology, the highest demands are placed on the purity of the soot bodies, so that their soot
Handhabung bei den weiteren Verarbeitungsschritten, beispielsweise einer Temperatur- oder einer Gasbehandlung, besondere Aufmerksamkeit zu widmen ist.Handling during the further processing steps, for example a temperature or gas treatment, must be given special attention.
Bei der Behandlung derartiger Sootkörper in einem Behandlungsraum, wie beispielsweise in einem Sinterofen, ergibt sich unter anderem das Problem der Halterung der mechanisch nur wenig belastbaren Sootkörper. Bei dem aus der US-PS 4,251 ,251 bekannten Verfahren besteht die Halterung aus einem aus Platindrähten geformten Bügel, an dem der hohlzylindrische Sootkörper aufgehängt wird. Zur Befestigung der Platindrähte am Sootkörper weist die Hohlzylinderwandung in ihrem oberen Bereich zwei waagrecht verlaufende Durchgangsbohrungen auf, durch die hindurch die Platindrähte geführt sind. Zum Sintern wird der Sootkörper kontinuierlich einem vertikal orientierten Sinterofen zugeführt. Dabei erweicht der Sootkörper in einer Erweichungszone. Die Erweichungszone beginnt am unteren Ende des Sootkörpers. Mit dem Absenken des Sootkörpers in den Sinterofen wandert die Erweichungszone im Sootkörper kontinuierlich nach oben. Dabei nimmt das an der Erweichungszone hängende Gewicht des bereits gesinterten Teils des Sootkörpers kontinuierlich zu. Aufgrund der geringen Viskosität in der Erweichungszone verlängert sich der Sootkörper daher beim Absenken unter seinem eigenen Gewicht. Das Verfahren ist daher insbesondere zum Sintern großvolumiger und schwerer Sootkörper nicht geeignet und es führt zu in ihren Abmessungen relativ ungenauen Quarzglaskörpern, die beispielsweise durch Überschleifen nachbearbeitet werden müssen.When treating such soot bodies in a treatment room, such as, for example, in a sintering furnace, there is, among other things, the problem of holding the soot bodies, which are mechanically only slightly resilient. In the method known from US Pat. No. 4,251,251, the holder consists of a bracket formed from platinum wires, on which the hollow cylindrical soot body is suspended. To attach the platinum wires to the soot body, the hollow cylinder wall has two horizontally extending through holes in its upper region, through which the platinum wires are guided. For sintering, the soot body is continuously fed to a vertically oriented sintering furnace. The soot body softens in a softening zone. The softening zone begins at the lower end of the soot body. With the Lowering the soot body into the sintering furnace continuously moves the softening zone in the soot body upwards. The weight of the already sintered part of the soot body hanging from the softening zone increases continuously. Due to the low viscosity in the softening zone, the soot body lengthens when it is lowered under its own weight. The method is therefore particularly unsuitable for sintering large-volume and heavy soot bodies and it leads to relatively imprecise quartz glass bodies in terms of their dimensions, which have to be reworked, for example, by grinding.
Ein anderes Verfahren zum Sintern bzw. Verglasen eines hohlzylindrischen Si02 Sootkörpers ist aus DE-A 44 32 806 bekannt, wobei der Hohlzylinder mittels einer Haltevorrichtung in vertikaler Ausrichtung gehalten und kontinuierlich einem Sinterofen zugeführt wird. Der Sootkörper sintert je nach Sinterabschnitt auf einem Haltefuß stehend oder an einer Tragestange hängend, wobei ein Hüllrohr in die Bohrung des Hohlzylinders eingeführt ist, dessen Außendurchmesser den Innendurchmesser des erhaltenen Quarzglasrohres bestimmt. Das Hüllrohr hat demnach eine gewisse formgebende Funktion für den zu verglasenden Sootkörper. Der Außendurchmesser des erhaltenen Quarzglaskörpers wird aber von derAnother method for sintering or vitrifying a hollow cylindrical Si0 2 soot body is known from DE-A 44 32 806, the hollow cylinder being held in a vertical orientation by means of a holding device and being continuously fed to a sintering furnace. Depending on the sintering section, the soot body sinters standing on a support foot or hanging on a support rod, a cladding tube being inserted into the bore of the hollow cylinder, the outside diameter of which determines the inside diameter of the quartz glass tube obtained. The cladding tube therefore has a certain shaping function for the soot body to be glazed. The outer diameter of the quartz glass body obtained is, however, of
Volumenkontraktion des Sootkörpers aufgrund seiner Sinteraktivität bestimmt, was allerdings nicht zu ausreichend exakten Abmessungen bzw. zu Verformungen (sogenannte Bananenform) führt. Es ist deshalb auch bei diesem Verfahren eine nachträgliche Überarbeitung des verglasten Quarzglaskörpers durch Überschleifen notwendig.Volume contraction of the soot body is determined on the basis of its sintering activity, but this does not lead to sufficiently exact dimensions or deformations (so-called banana shape). It is therefore also necessary with this method to rework the glazed quartz glass body by grinding.
Ein Verfahren, bei dem ein stabförmiger Sootkörper aus Siliziumdioxid innerhalb einer Form verglast wird, ist aus DE 3521 119 A1 bekannt. Hierbei besteht die Form selbst auch aus Quarzglas und bildet das Mantelglas einer Vorform für optische Fasern. Während des Durchgangs durch eine Heizzone schrumpft das Mantelglas unlösbar auf den verglasenden Sootkörper auf. Dieses Verfahren ist allein auf die Herstellung einer Vorform für optische Fasern gerichtet. Die unlösbare Verbindung des Mantelglases mit dem zu verglasenden Sootkörper im Innern ist für diese Anwendung sinnvoll. Eine allgemeine formgebende Verglasung von Sootkörpern aus Siliziumdioxid mittels Quarzglasformen ist aber nachteilig, da nach dem Verglasen der äußere Bereich des erhaltenenA method in which a rod-shaped soot body made of silicon dioxide is glazed within a mold is known from DE 3521 119 A1. The shape itself is also made of quartz glass and forms the cladding glass of a preform for optical fibers. During the passage through a heating zone, the cladding glass shrinks inextricably onto the glazing soot body. This procedure is solely aimed at producing an optical fiber preform. The permanent connection between the cladding glass and the soot body to be glazed inside is useful for this application. A general shaping glazing of soot bodies made of silicon dioxide by means of quartz glass molds is disadvantageous, since after the glazing the outer area of the obtained
Quarzglaskörpers, der der ursprünglichen Form entspricht, beispielsweise durch aufwendiges Abschleifen wieder entfernt werden müsste. Ferner ist nicht auszuschließen, dass im Querschnitt des erhaltenen Quarzglaskörpers am Übergangsbereich zwischen dem ursprünglichen Sootkörper und der Quarzglasform unerwünschte Sprünge in den Glaseigenschaften zu verzeichnen sind.Quartz glass body, which corresponds to the original shape, for example, would have to be removed again by complex grinding. Furthermore, it cannot be ruled out that in the cross section of the quartz glass body obtained at the transition area between the original soot body and the quartz glass shape, undesirable jumps in the glass properties can be recorded.
Es ist daher Aufgabe der vorliegenden Erfindung, ein für das Verglasen großvolumiger, poröser Sootkörper aus Siliziumdioxid geeignetes, kostengünstiges Verfahren anzugeben, bei dem die Nachbearbeitungsschritte zur Optimierung der äußeren Abmessungen des erhaltenen Quarzglaskörpers minimiert werden können.It is therefore an object of the present invention to provide an inexpensive method which is suitable for vitrification of large-volume, porous soot bodies made of silicon dioxide and in which the postprocessing steps for optimizing the outer dimensions of the quartz glass body obtained can be minimized.
Diese Aufgabe wird ausgehend von den eingangs genannten Verfahren erfindungsgemäß dadurch gelöst, dass der Sootkörper innerhalb derBased on the methods mentioned at the outset, this object is achieved according to the invention in that the soot body within the
Erhitzungszone auf eine Temperatur erhitzt wird, bei der er soweit erweicht, dass er unter Bildung eines verglasten Sootkörpers die lateralen Abmessungen der Form annimmt, und dass der verglaste Sootkörper von der Form gelöst wird.Heating zone is heated to a temperature at which it softens to the extent that it takes on the lateral dimensions of the mold to form a glazed soot body, and that the glazed soot body is detached from the mold.
Bei Raumtemperatur ist der zu sinternde Sootkörper im wesentlichen formstabil. Das heißt, er kann vertikal aufgestellt oder aufgehängt werden, ohne dass er sich unter seinem eigenen Gewicht plastisch verformt. Bei Temperaturerhöhung erweicht der Siliziumdioxid-Soot in der Erhitzungszone. Seine Viskosität nimmt ab, so dass sich der Sootkörper unter den auf die Erweichungszone einwirkenden Kräften verformt. Neben der Schwerkraft wirken dabei auch Verformungskräfte infolge einer Volumenkontraktion auf den Sootkörper ein. Der Sootkörper weist eine Dichte von nur ca. 30 % des festen Quarzglases auf. Da das Sintern oder Verglasen kontinuierlich erfolgt, wandert die Erweichungszone von einem Ende des Sootkörpers zu dem gegenüberliegenden Ende.The soot body to be sintered is essentially dimensionally stable at room temperature. This means that it can be set up or hung up vertically without plastically deforming under its own weight. When the temperature rises, the silicon dioxide soot softens in the heating zone. Its viscosity decreases, so that the soot body deforms under the forces acting on the softening zone. In addition to gravity, it also works Deformation forces due to a volume contraction on the soot body. The soot body has a density of only approx. 30% of the solid quartz glass. Since the sintering or vitrification takes place continuously, the softening zone moves from one end of the soot body to the opposite end.
Bei dem erfindungsgemäßen Verfahren wird der Sootkörper in die Erhitzungszone eines Sinter- oder Verglasungsofens kontinuierlich eingebracht und dabei auf eine Temperatur aufgeheizt, bei der der Sootkörper soweit erweicht, dass er in eine ihn umgebende Form ausfließt bzw. die Hohlmaße einer ihn umgebenden Form ausfüllt. Die Form selbst kann dabei entweder bereits vor dem Eintauchen des Sootkörpers in die Erhitzungszone mit dem Sootkörper mitgeführt werden oder sie befindet sich innerhalb des Sinterofens und nimmt den Sootkörper erst dort auf. Die Form ist so beschaffen, dass der erweichende Sootkörper oder der verglaste Quarzglaskörper nicht an ihr haftet und somit zerstörungsfrei von ihr lösbar ist. Die Form kann dafür zweckmäßigerweise aus mehreren zusammensetzbaren Teilen bestehen. Das erfindungsgemäße Verfahren ermöglicht ein kontinuierliches Verglasen von Sootkörpern mit relativ präziser Vorbestimmung der Endabmessungen des zu erhaltenden Quarzglaskörpers. Verzug oder Verformungen des verglasenden Sootkörpers, wie sie bei dem Verfahren nach dem Stand der Technik zu beobachten sind, werden mit dem erfindungsgemäßen Verfahren ausgeschlossen.In the method according to the invention, the soot body is continuously introduced into the heating zone of a sintering or glazing furnace and is thereby heated to a temperature at which the soot body softens to such an extent that it flows out into a shape surrounding it or fills the hollow dimensions of a shape surrounding it. The shape itself can either be carried with the soot body before the soot body is immersed in the heating zone or it is located within the sintering furnace and only takes up the soot body there. The shape is such that the softening soot body or the glazed quartz glass body does not adhere to it and can therefore be removed from it without destroying it. The shape can expediently consist of several parts that can be assembled. The method according to the invention enables soot bodies to be vitrified continuously with relatively precise predetermination of the final dimensions of the quartz glass body to be obtained. Distortion or deformation of the glazing soot body, as can be observed in the method according to the prior art, are excluded with the method according to the invention.
Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen 2 bis 10 aufgeführt.Advantageous embodiments of the invention are set out in subclaims 2 to 10.
Das erfindungsgemäße Verfahren hat sich besonders bewährt, wenn zumindest am oberen Ende des zu verglasenden Sootkörpers eine Haltevorrichtung angreift, wobei als Haltevorrichtung ein zylindrischer Graphitstab vorteilhaft ist, der durch die Längsbohrung des hohlzylindrischen Sootkörpers geführt ist, und der zur Stabilisierung des Sootkörpers beiträgt. Die Haltevorrichtung kann zusätzlich den Sootkörper auch an der Basis stützen.The method according to the invention has proven particularly useful when a holding device acts at least on the upper end of the soot body to be glazed, a cylindrical graphite rod which is guided through the longitudinal bore of the hollow cylindrical soot body being advantageous as the holding device, and which helps stabilize the soot body. The holding device can also support the soot body at the base.
Zur exakten Steuerung der Verglasung und der Kontrolle der damit einhergehenden Geometrieänderungen des Quarzglaskörpers, wird die Haltevorrichtung in vertikaler Richtung mit regelbarer oder steuerbarer Bewegungsgeschwindigkeit mittels einer Bewegungseinheit derart bewegt, dass der Sootkörper entsprechend seiner Längenkontraktion der Erhitzungszone zugeführt wird. Die Haltevorrichtung ist mit einer Bewegungseinheit verbunden. Die vertikale Bewegung der Haltevorrichtung mit dem Sootkörper ist entsprechend der Längenkontraktion des Sootkörpers während der Verglasung steuerbar oder regelbar. Das heißt die Zuführungsgeschwindgkeit in die Erhitzungszone kann variiert und an die Volumen- und Längenkontraktion angepasst werden.For precise control of the glazing and the control of the associated changes in the geometry of the quartz glass body, the holding device is moved in the vertical direction with a controllable or controllable movement speed by means of a movement unit such that the soot body is fed to the heating zone in accordance with its length contraction. The holding device is connected to a movement unit. The vertical movement of the holding device with the soot body can be controlled or regulated in accordance with the contraction in length of the soot body during the glazing. This means that the feed rate into the heating zone can be varied and adapted to the volume and length contraction.
Der poröse Sootkörper wird zweckmäßig nach dem Flammhydrolyseverfahren hergestellt. Die bei der Flammhydrolyse anfallenden Si02 Partikel werden auf einem Träger aufgefangen und bilden den porösen Sootkörper. Ist der Träger beispielsweise eine zylindrische Stange, die nach dem Abscheiden wieder entfernt wird, so erhält man einen hohlzylindrischen Sootkörper.The porous soot body is expediently produced by the flame hydrolysis process. The Si0 2 particles resulting from flame hydrolysis are collected on a support and form the porous soot body. If the carrier is, for example, a cylindrical rod which is removed again after the separation, a hollow cylindrical soot body is obtained.
Ein hohlzylindrischer Sootkörper bietet den Vorteil, dass, soweit der Hohlraum beim Verglasen bewußt beibehalten wird, in den Hohlraum bei Bedarf ein Quarzglasstab eingesetzt werden kann, der den Kern für eine Vorform bildet, aus der optische Fasern gezogen werden können. Das Si02-Mateπ'al von einem derartigen Kernstab und vom dem den Kemstab umgebenden Mantel kann sich in Bezug auf Dotierstoffe unterscheiden.A hollow cylindrical soot body has the advantage that, as long as the cavity is deliberately maintained during glazing, a quartz glass rod can be inserted into the cavity if necessary, which forms the core for a preform from which optical fibers can be drawn. The Si0 2 -Mateπ ' al from such a core rod and from the jacket surrounding the core rod can differ in terms of dopants.
Um aus dem porösen Sootkörper einen dichten, blasen- und schlierenfreien Quarzglaskörper zu erhalten, ist es zweckmäßig die Temperatur für die Verglasung auf einen Wert im Bereich zwischen 1300°C und 1750°C einzustellen. Dabei erfolgt die Verglasung vorzugsweise in zwei Schritten mit einer Vorsinterung bei etwa 1300 bis 1350°C und einer endgültigen Verglasung bei etwa 1700 bis 1750°C.In order to obtain a dense, bubble-free and streak-free quartz glass body from the porous soot body, it is expedient to set the temperature for the glazing to a value in the range between 1300 ° C. and 1750 ° C. adjust. The glazing is preferably carried out in two steps with a pre-sintering at approximately 1300 to 1350 ° C. and a final glazing at approximately 1700 to 1750 ° C.
Hinsichtlich des Formmaterials für das erfindungsgemäße Verfahren ist ein bis 1800°C stabiles Material zweckmäßig. Keramische Werkstoffe sind für derartige Anwendungen geeignet. Graphit oder Siliziumkarbid hat sich besonders bewährt. Das Formmaterial kann gasdurchlässig sein, um eine Gasbeaufschlagung oder auch eine Gasabführung während oder vor der Verglasung zu ermöglichen oder zu verbessern. Es können verschiedene Graphitqualitäten eingesetzt werden, wobei besonders kohlenstofffaserverstärkter Graphit (CFC) geeignet ist. Neben den keramischen Formmaterialien sind auch hochschmelzende Metalle, vorzugsweise Molybdän oder Platin geeignet.With regard to the molding material for the process according to the invention, a material that is stable up to 1800 ° C. is expedient. Ceramic materials are suitable for such applications. Graphite or silicon carbide has proven particularly useful. The molding material can be gas-permeable in order to enable or improve the application of gas or also the removal of gas during or before the glazing. Different grades of graphite can be used, carbon-fiber-reinforced graphite (CFC) being particularly suitable. In addition to the ceramic molding materials, refractory metals, preferably molybdenum or platinum, are also suitable.
Vor dem Einstellen der Temperatur zum Verglasen des Sootkörpers wird dieser jedoch zum Austreiben von Wasser aus dem Soot mit einem halogenhaltigen Gas beaufschlagt. Als halogenhaltiges Gas hat sich Chlorgas bewährt. Dieser Behandlungsschritt wird auch als Chlorierung bezeichnet. Die Chlorierung kann als getrennter Verfahrensschritt vor dem Verglasen des Sootkörpers erfolgen, oder aber wenn sich der Sootkörper (innerhalb oder noch außerhalb der Form) bereits im Verglasungsofen befindet, bevor jedoch die Versinterung des Soots einsetzt, das heißt in einem Temperaturbereich zwischen 800°C und etwa 1200°C.Before setting the temperature for vitrifying the soot body, however, a halogen-containing gas is applied to expel water from the soot. Chlorine gas has proven itself as a halogen-containing gas. This treatment step is also called chlorination. The chlorination can take place as a separate process step before the soot body is vitrified, or if the soot body is already in the glazing furnace (inside or outside the mold), but before the soot sinters, i.e. in a temperature range between 800 ° C and about 1200 ° C.
Weiterhin ist es zweckmäßig, wenn die Verglasung des Sootkörpers unter Vakuum oder Schutzgasatmosphäre erfolgt, da hierdurch sowohl eine Oxidation des Formenmaterials Graphit oder auch Molybdän vermieden oder weitgehend reduziert, als auch eine hohe Qualität hinsichtlich Reinheit für den zu verglasenden Sootkörper gewährleistet wird . Als Schutzgase haben sich Argon, Helium oder Stickstoff bewährt. Besonders bevorzugt wird wegen relativ guter Wärmeübertragung eine Helium-Atmosphäre.It is also expedient if the soot body is glazed under a vacuum or protective gas atmosphere, since this prevents or largely reduces oxidation of the graphite or molybdenum mold material, and also ensures high quality in terms of purity for the soot body to be glazed. Argon, Helium or nitrogen proven. A helium atmosphere is particularly preferred because of the relatively good heat transfer.
Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und werden nachfolgend erläutert. In der Zeichnung zeigen die Figuren 1 und 2 in schematischer Darstellung einfache Verglasungsvorrichtungen für das erfindungsgemäße Verfahren.Embodiments of the invention are shown in the drawing and are explained below. In the drawing, FIGS. 1 and 2 show a schematic illustration of simple glazing devices for the method according to the invention.
Die Vorrichtung gemäß Figur 1 weist einen Ofen 1 mit einem vertikalen, zylindrischen Schutzrohr auf, das außen von Heizelementen 2 umfaßt wird. Die Heizelemente 2 erzeugen im Ofen eine Erhitzungszone 2a (in Fig. 1 und 2 schematisch angedeutet durch horizontale, gestrichelte Begrenzungslinien innerhalb des Ofen-Schutzrohres). Der zu verglasende, hohlzylindrische Sootkörper 3 befindet sich - nach einer Chlorierung (Chlorgasstrom 36 l/h) bei 1000°C - nun in die Graphitform 4, wobei zur Stabilisierung des Sootkörpers 3 ein Haltestab 5 in die Längsbohrung des Sootkörpers 3 eingeführt ist. Der Haltestab 5 greift mit einem Teller 6 am oberen Ende des Sootkörpers 3 an und stützt sich zusätzlich auf dem Boden der Graphitform 4 ab. Die Graphitform 4 wird mittels einer Bewegungseinheit 7 langsam von oben in den Ofen 1 zugeführt, so dass zuerst der untere Teil des Sootkörpers 3 die Heizzone 2a erreicht und dort verglast. Um eine vollständige Verglasung zu gewährleisten, ist die Temperatur im heißesten Bereich der Heizzone 2a auf etwa 1700°C eingestellt. Im Ofen 1 herrscht ein Vakuum von 0,1mbar. Bei weiteren Absenken der Graphitform 4 mit dem Sootkörper 3 wandert der verglaste Bereich des Sootkörpers 3 weiter nach oben bis ein vollständig verglaster Quarzglaskörper entstanden ist. Austretende Restgase können nach oben durch den porösen Teil des Sootkörpers 3 abgeführt werden. Durch geeignete Auswahl der Formgeometrie und der Absenkgeschwindigkeit nimmt der langsam verglasende Sootkörper 3 die Hohlmaße der ihn umgebenden Form 4 an. Typische Abmessungen des Sootkörpers 3 vor dem Verglasen liegen im Bereich von 400 bis 450 mm für den Außendurchmesser und bei einer Länge von 2,5 bis 3,0 Metern. Der Durchmesser der Längsbohrung bzw. des Haltestabes 5 beträgt etwa 50 bis 80 mm. Bei einer mittleren Vorschubgeschwindigkeit der Bewegungseinheit 7 von etwa 3 mm/min (abwärts) kann ein verglaster Quarzglas-Hohlzylinder mit einem Aussendurchmesser von 150 bis 200 mm (Durchmesser der Bohrung etwa 50 bis 80 mm) und einer Länge von 2 Metern erhalten werden. Grundsätzlich ist es auch möglich die Heizelemente 2 anstelle des Sootkörpers 3 zu bewegen, und zwar müssen in diesem Fall die Heizelemente 2 von unten nach oben bewegt werden.The device according to FIG. 1 has an oven 1 with a vertical, cylindrical protective tube, which is surrounded on the outside by heating elements 2. The heating elements 2 generate a heating zone 2a in the furnace (indicated schematically in FIGS. 1 and 2 by horizontal, dashed boundary lines within the furnace protection tube). The hollow cylindrical soot body 3 to be glazed is now - after chlorination (chlorine gas flow 36 l / h) at 1000 ° C. - in the graphite mold 4, with a holding rod 5 being inserted into the longitudinal bore of the soot body 3 to stabilize the soot body 3. The holding rod 5 engages with a plate 6 at the upper end of the soot body 3 and is additionally supported on the bottom of the graphite mold 4. The graphite mold 4 is slowly fed into the furnace 1 from above by means of a movement unit 7, so that the lower part of the soot body 3 first reaches the heating zone 2a and is glazed there. To ensure complete glazing, the temperature in the hottest area of heating zone 2a is set to approximately 1700 ° C. A vacuum of 0.1 mbar prevails in the furnace 1. When the graphite mold 4 is lowered further with the soot body 3, the glazed area of the soot body 3 moves further upwards until a completely glazed quartz glass body has formed. Escaping residual gases can be discharged upwards through the porous part of the soot body 3. Through a suitable selection of the shape geometry and the lowering speed, the slowly glazing soot body 3 assumes the hollow dimensions of the shape 4 surrounding it. Typical dimensions of the soot body 3 before glazing are in the range from 400 to 450 mm for the outer diameter and with a length of 2.5 to 3.0 meters. The diameter of the longitudinal bore or the holding rod 5 is approximately 50 to 80 mm. With an average feed speed of the movement unit 7 of approximately 3 mm / min (downwards), a glazed quartz glass hollow cylinder with an outer diameter of 150 to 200 mm (diameter of the bore approximately 50 to 80 mm) and a length of 2 meters can be obtained. In principle, it is also possible to move the heating elements 2 instead of the soot body 3, and in this case the heating elements 2 must be moved from the bottom up.
Nach dem langsamen Abkühlen des Quarzglaskörpers in der Graphitform 4, kann dieser zerstörungsfrei von der Graphitform 4 gelöst werden. Eine Nachbearbeitung auf gewünschte Endabmessungen kann in der Regel entfallen.After slow cooling of the quartz glass body in the graphite mold 4, it can be detached from the graphite mold 4 without destruction. Post-processing to the desired final dimensions can usually be omitted.
In Figur 2 ist eine Vorrichtung für das erfindungsgemäße Verfahren dargestellt, das eine integrierte Chlorierung umfaßt und gegenüber der Geometrie des Sootkörpers 3 stärker abweichende Endabmessungen des verglasten Quarzglaskörpers erlaubt. Der zu verglasende Sootkörper 3 befindet sich gemäß Figur 2 in einem oberen Teil einer gasdurchlässigen Graphitform 4a, die zunächst in einen oberen, aber kälteren Bereich eines wie mit Figur 1 erläuterten Ofens 1 eingelassen und mit Chlorgas beaufschlagt wird. Die Temperatur während der Chlorierung beträgt etwa 950°C bei 10 Vol% Cl2 in Helium (Cl2/He). Die Gaszufuhr in den Ofen 1 erfolgt von unten. Das Gas durchströmt den Sootkörper 3 und wird durch die zumindest im oberen Bereich gasdurchlässige Graphitform 4a wieder nach außen geführt. Nach diesem Prozeßschritt wird der Sootkörper 3 zusammen mit der Form 4a langsam weiter in höhere Temperaturbereiche abgesenkt, so dass eine Vorsinterphase beiFIG. 2 shows a device for the method according to the invention, which comprises integrated chlorination and allows the end dimensions of the glazed quartz glass body to differ more than the geometry of the soot body 3. According to FIG. 2, the soot body 3 to be glazed is located in an upper part of a gas-permeable graphite mold 4a, which is initially let into an upper but colder area of an oven 1 as explained with FIG. 1 and is charged with chlorine gas. The temperature during the chlorination is about 950 ° C at 10 vol% Cl 2 in helium (Cl 2 / He). The gas is fed into the furnace 1 from below. The gas flows through the soot body 3 and is led outwards again through the graphite form 4a which is gas-permeable at least in the upper region. After this process step, the soot body 3, together with the mold 4a, is slowly lowered further into higher temperature ranges, so that a pre-sintering phase at
1350°C in Helium Atmosphäre erfolgt. Diese Bedingungen werden für etwa 12 h konstant gehalten. Während des Sinterns ist bereits eine Volumenkontraktion des Sootkörpers 3 zu beobachten. Die endgültige Verglasung erfolgt bei 1750°C, wobei die Graphitform 4a mit dem vorgesinterten Sootkörper 3 noch ein Stück in Richtung der höheren Temperatur bewegt wird. Bei einer Verweilzeit von 8 Stunden in dieser Position erweicht der vorgesinterte Sootkörper 3 soweit, dass er durch einen trichterförmigen Übergang 4b der Form 4a vom oberen, weiten Bereich der Graphitform 4a in einen unteren Teil der Form mit wesentlich kleinerem Durchmesser „fließt". Das zähe Fließen kann durch Herunterdrücken des Tellers 6 des Haltestabes 5 oder eine andere geeignete Auflage unterstützt werden. Nach dem Erkalten des1350 ° C in a helium atmosphere. These conditions will last for about 12 h kept constant. A volume contraction of the soot body 3 can already be observed during the sintering. The final glazing takes place at 1750 ° C., the graphite mold 4a with the presintered soot body 3 being moved a little further in the direction of the higher temperature. With a residence time of 8 hours in this position, the presintered soot body 3 softens to such an extent that it "flows" through a funnel-shaped transition 4b of the shape 4a from the upper, wide area of the graphite shape 4a into a lower part of the shape with a much smaller diameter Flow can be supported by pressing down the plate 6 of the holding rod 5 or another suitable support
Quarzglaskörpers wird die Graphitform 4a entfernt. Eine Nachbearbeitung des Quarzglaskörpers ist nicht erforderlich. The graphite mold 4a is removed from the quartz glass body. It is not necessary to rework the quartz glass body.

Claims

Patentansprüche claims
1. Verfahren zum Verglasen eines porösen Sootkörpers aus Siliziumdioxid, bei dem der Sootkörper mittels einer Haltevorrichtung in vertikaler Ausrichtung gehalten und kontinuierlich einer Erhitzungszone zugeführt wird, wobei der1. A method for vitrifying a porous soot body made of silicon dioxide, in which the soot body is held in a vertical orientation by means of a holding device and is continuously fed to a heating zone, the
Sootkörper zumindest ab Eintritt in die Erhitzungszone von einer Form umgeben ist, dadurch gekennzeichnet, dass der Sootkörper (3) innerhalb der Erhitzungszone (2a) auf eine Temperatur erhitzt wird, bei der er soweit erweicht, dass er unter Bildung eines verglasten Sootkörpers (3) die lateralen Abmessungen der Form (4; 4a) annimmt, und dass der verglasteSoot body is surrounded by a shape at least from the point of entry into the heating zone, characterized in that the soot body (3) is heated to a temperature within the heating zone (2a) at which it softens to the extent that it forms a glazed soot body (3). the lateral dimensions of the form (4; 4a) and that of the glazed
Sootkörper (3) von der Form (4; 4a) gelöst wird.Soot body (3) from the mold (4; 4a) is released.
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, dass der Sootkörper während der Verglasung eine Längenkontraktion erfährt, und dass die Haltevorrichtung (5) in vertikaler Richtung mit regelbarer oder steuerbarer Bewegungsgeschwindigkeit mittels einer Bewegungseinheit (7) derart bewegt wird, dass der Sootkörper (3) entsprechend seiner Längenkontraktion der Erhitzungszone (2a) zugeführt wird.2. The method according to claim 1, characterized in that the soot body undergoes a length contraction during the glazing, and that the holding device (5) is moved in the vertical direction with adjustable or controllable movement speed by means of a movement unit (7) such that the soot body (3 ) is fed to the heating zone (2a) according to its length contraction.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der poröse Sootkörper (3) ein nach dem Flammhydrolyseverfahren hergestellter Sootkörper (3) ist.3. The method according to claim 1 or 2, characterized in that the porous soot body (3) is a soot body (3) produced by the flame hydrolysis process.
4. Verfahren nach einem der Ansprüche Ibis 3, dadurch gekennzeichnet, dass als poröser Sootkörper (3) ein Hohlzylinder eingesetzt wird.4. The method according to any one of claims 3, characterized in that a hollow cylinder is used as the porous soot body (3).
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass die für die Verglasung des Sootkörpers (3) erforderliche Temperatur auf einen Wert im Bereich von 1300°C bis 1750X eingestellt wird. 5. The method according to any one of claims 1 to 4, characterized in that the temperature required for the glazing of the soot body (3) is set to a value in the range from 1300 ° C to 1750X.
6. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die den Sootkörper (3) umgebende Form (4; 4a) aus einem bis 1800°C stabilem Material besteht.6. The method according to any one of claims 1 to 5, characterized in that the soot body (3) surrounding shape (4; 4a) consists of a stable to 1800 ° C material.
7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, dass die den Sootkörper (3) umgebende Form (4; 4a) aus einem keramischen Material, vorzugsweise aus Graphit oder aus Siliziumkarbid, oder aus einem hochschmelzenden Metall, vorzugsweise aus Molybdän oder Platin, besteht.7. The method according to claim 6, characterized in that the soot body (3) surrounding shape (4; 4a) consists of a ceramic material, preferably of graphite or silicon carbide, or of a high-melting metal, preferably of molybdenum or platinum.
8. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass vor dem Einstellen der Temperatur zum Verglasen der Sootkörper (3) mit einem halogenhaltigen Gas beaufschlagt wird.8. The method according to any one of claims 1 to 7, characterized in that a halogen-containing gas is applied to the soot body (3) before the temperature is set for glazing.
9. Verfahren nach einem der Ansprüche 1 bis 8 dadurch gekennzeichnet, dass das Verglasen des Sootkörpers (3) unter Vakuum oder unter einer Schutzgasatmosphäre erfolgt.9. The method according to any one of claims 1 to 8, characterized in that the glazing of the soot body (3) is carried out under vacuum or under a protective gas atmosphere.
10. Verfahren nach Anspruch 9, dadurch gekennzeichnet, dass das Verglasen des Sootkörpers (3) unter einer Argon- und/oder Helium- und/oder Stickstoff-Schutzgasatmosphäre erfolgt. 10. The method according to claim 9, characterized in that the vitrification of the soot body (3) takes place under an argon and / or helium and / or nitrogen protective gas atmosphere.
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DE10041467A DE10041467C1 (en) 2000-07-26 2000-08-23 Process for vitrifying a porous soot body made of silicon dioxide used in the production of blanks for optical fibers comprises holding the soot body in a vertical position using a holding device, and continuously feeding to a heating zone
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004067458A2 (en) * 2003-01-28 2004-08-12 Heraeus Tenevo Gmbh Method for the production of a hollow cylinder made of synthetic quartz glass with the aid of a holding device, and appropriate holding device for carrying out said method
WO2005097693A1 (en) * 2004-04-07 2005-10-20 Heraeus Tenevo Gmbh Method for producing a hollow cylinder from synthetic quartz glass, using a retaining device
WO2006068136A1 (en) * 2004-12-21 2006-06-29 Mitsubishi Materials Corporation OXIDE FILM COATED Fe-Ni-Mo BASED FLAT METAL SOFT MAGNETIC POWDER HAVING HIGH SURFACE ROUGHNESS AND METHOD FOR PRODUCTION THEREOF
WO2009090257A1 (en) * 2008-01-18 2009-07-23 Heraeus Quartz Uk Limited Heat treatment furnaces
US8393179B2 (en) 2006-05-24 2013-03-12 Heraeus Quarzglas Gmbh & Co. Kg Method for producing a semifinished product from synthetic quartz glass
US9701561B2 (en) 2010-07-09 2017-07-11 Heraeus Quartz UK Ltd. High purity synthetic silica and items such as semiconductor jigs manufactured therefrom

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1529385A (en) * 1975-06-13 1978-10-18 Heraeus Schott Quarzschmelze Tubes of non-circular cross-section and the manufacture thereof
JPH01224236A (en) * 1988-03-01 1989-09-07 Furukawa Electric Co Ltd:The Making porous optical fiber preform into transparent glass
JPH05170473A (en) * 1991-12-18 1993-07-09 Shin Etsu Chem Co Ltd Production of preform for optical fiber
JPH05339012A (en) * 1992-06-08 1993-12-21 Fujikura Ltd Heating treatment device for glass preform
JPH07330362A (en) * 1994-06-06 1995-12-19 Fujikura Ltd Method for processing tip of preformed material for spinning glass fiber and apparatus therefor
DE19736949C1 (en) * 1997-08-25 1999-01-21 Heraeus Quarzglas Quartz glass articles production

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8403380A (en) * 1984-11-07 1986-06-02 Philips Nv METHOD AND APPARATUS FOR COMPACTING A PREFORMED POROUS BODY OF MATERIAL, THE MAIN COMPONENT OF WHICH IS SIO2.
JPS63147839A (en) * 1986-12-10 1988-06-20 Furukawa Electric Co Ltd:The Doping method for porous glass base material
JPH02149442A (en) * 1988-12-01 1990-06-08 Sumitomo Electric Ind Ltd Production of optical fiber preform

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1529385A (en) * 1975-06-13 1978-10-18 Heraeus Schott Quarzschmelze Tubes of non-circular cross-section and the manufacture thereof
JPH01224236A (en) * 1988-03-01 1989-09-07 Furukawa Electric Co Ltd:The Making porous optical fiber preform into transparent glass
JPH05170473A (en) * 1991-12-18 1993-07-09 Shin Etsu Chem Co Ltd Production of preform for optical fiber
JPH05339012A (en) * 1992-06-08 1993-12-21 Fujikura Ltd Heating treatment device for glass preform
JPH07330362A (en) * 1994-06-06 1995-12-19 Fujikura Ltd Method for processing tip of preformed material for spinning glass fiber and apparatus therefor
DE19736949C1 (en) * 1997-08-25 1999-01-21 Heraeus Quarzglas Quartz glass articles production

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 13, no. 546 6 December 1989 (1989-12-06) *
PATENT ABSTRACTS OF JAPAN vol. 17, no. 577 20 October 1993 (1993-10-20) *
PATENT ABSTRACTS OF JAPAN vol. 18, no. 176 25 March 1994 (1994-03-25) *
PATENT ABSTRACTS OF JAPAN vol. 1996, no. 4 30 April 1996 (1996-04-30) *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004067458A2 (en) * 2003-01-28 2004-08-12 Heraeus Tenevo Gmbh Method for the production of a hollow cylinder made of synthetic quartz glass with the aid of a holding device, and appropriate holding device for carrying out said method
WO2004067458A3 (en) * 2003-01-28 2005-02-24 Heraeus Tenevo Ag Method for the production of a hollow cylinder made of synthetic quartz glass with the aid of a holding device, and appropriate holding device for carrying out said method
CN100335430C (en) * 2003-01-28 2007-09-05 赫罗伊斯·坦尼沃有限责任公司 Method for the production of a hollow cylinder made of synthetic quartz glass with the aid of a holding device, and appropriate holding device for carrying out said method
WO2005097693A1 (en) * 2004-04-07 2005-10-20 Heraeus Tenevo Gmbh Method for producing a hollow cylinder from synthetic quartz glass, using a retaining device
WO2006068136A1 (en) * 2004-12-21 2006-06-29 Mitsubishi Materials Corporation OXIDE FILM COATED Fe-Ni-Mo BASED FLAT METAL SOFT MAGNETIC POWDER HAVING HIGH SURFACE ROUGHNESS AND METHOD FOR PRODUCTION THEREOF
US8393179B2 (en) 2006-05-24 2013-03-12 Heraeus Quarzglas Gmbh & Co. Kg Method for producing a semifinished product from synthetic quartz glass
WO2009090257A1 (en) * 2008-01-18 2009-07-23 Heraeus Quartz Uk Limited Heat treatment furnaces
US9701561B2 (en) 2010-07-09 2017-07-11 Heraeus Quartz UK Ltd. High purity synthetic silica and items such as semiconductor jigs manufactured therefrom

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