EP1218300A1 - Appareil de fabrication de preforme de verre par hydrolyse a la flamme - Google Patents

Appareil de fabrication de preforme de verre par hydrolyse a la flamme

Info

Publication number
EP1218300A1
EP1218300A1 EP00959949A EP00959949A EP1218300A1 EP 1218300 A1 EP1218300 A1 EP 1218300A1 EP 00959949 A EP00959949 A EP 00959949A EP 00959949 A EP00959949 A EP 00959949A EP 1218300 A1 EP1218300 A1 EP 1218300A1
Authority
EP
European Patent Office
Prior art keywords
flame
burner
soot
streams
forming
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00959949A
Other languages
German (de)
English (en)
Inventor
Arnab Sarkar
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bular LLC
Original Assignee
Bular LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bular LLC filed Critical Bular LLC
Publication of EP1218300A1 publication Critical patent/EP1218300A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/01413—Reactant delivery systems
    • C03B37/0142—Reactant deposition burners
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00—Other methods of shaping glass
    • C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
    • C03B19/1415—Reactant delivery systems
    • C03B19/1423—Reactant deposition burners
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C03B2207/06—Concentric circular ports
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C03B2207/08—Recessed or protruding ports
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C03B2207/12—Nozzle or orifice plates
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C03B2207/14—Tapered or flared nozzles or ports angled to central burner axis
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C03B2207/18—Eccentric ports
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/20—Specific substances in specified ports, e.g. all gas flows specified
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/20—Specific substances in specified ports, e.g. all gas flows specified
    • C03B2207/26—Multiple ports for glass precursor
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/50—Multiple burner arrangements
    • C03B2207/54—Multiple burner arrangements combined with means for heating the deposit, e.g. non-deposition burner

Definitions

  • This invention relates generally to apparatus for making glass preforms by flame hydrolysis and, more particularly, to such apparatus that produce glass preforms at a higher deposition rate and an improved efficiency.
  • cylindrical glass preforms for use in making optical fibers have been produced by manufacturing synthetic vitreous silica, using a two-step process of soot deposition by flame hydrolysis and sintering.
  • Two major optical fiber production processes that use this flame hydrolysis process are called outside vapor deposition (OVD) and vapor phase axial deposition (VAD).
  • Two other commercial optical fiber production processes, which do not use flame hydrolysis, are called modified chemical vapor deposition (MCVD) and plasma chemical vapor deposition (PCVD).
  • the basic process of flame hydrolysis was invented more than 50 years ago. It was first commercialized in a one-step deposition process, in which the deposition temperature was maintained sufficiently high for the deposited material to be a dully-dense clear glass.
  • the two-step deposition in which a porous preform is first deposited at a significantly lower temperature and then sintered into a clear glass, was later commercialized, with the advent of optical fibers.
  • This two- step process also has been adapted to other applications, because it permits the production of materials incorporating fewer hydroxyl ions.
  • silicon-containing precursor materials of various kinds are vaporized and then fed with reactant gases to a burner that produces an oxy-hydrogen or oxy-gas flame within a deposition chamber.
  • thermophoresis in which particles present in a thermal gradient are caused to move towards the colder surface.
  • Deposition rate and soot collection efficiency are two key parameters affecting process economy. These parameters are controlled in large part by the configurations of the burner and the deposition chamber. In designing these components, it must be recognized that the deposition can occur over a range of shapes, one of which being a cylindrical rod shape. In cylindrical deposition, the starting mandrel diameter can be less than 1 cm and the final diameter can be greater than 40 cm. In addition, it is important to maintain the temperature of the deposition surface sufficiently high to provide a high soot density and prevent cracking, but not so high as to cause partial sintering, which can form bubbles in the sintered glass. The diameter of the deposited material must be uniform, and the ends of the deposited material must be maintained at a temperature sufficiently high to prevent flaking.
  • the efficiency of the flame hydrolysis process described briefly above depends on many factors, including the choice of reactants, the choice of flame gases, the choice of the starting diameter and final diameter of the deposited material, the design of the burner, and the design of the deposition chamber.
  • Numerous burner configurations have been developed over the years for use in the optical fiber industry, the most common being referred to as concentric tube burners and aperture burners. Schematic diagrams of such burners are shown in FIGS. 1 and 2, respectively.
  • Another common type of burner, used in the fused silica products industry combines certain characteristics of both concentric tube burners and aperture burners. A schematic diagram of the face of such a burner is shown in FIG. 3.
  • These burners use oxy-hydrogen or oxy-gas flames, and they function as surface mixed and premixed burners.
  • These burners typically are constructed of fused silica glass or metals, such as aluminum or stainless steel.
  • the basic burner configurations of FIGS. 1-3 have the common design feature of circular symmetry.
  • the reacting chemicals are ejected in a stream from the center of the burner, and a shield gas stream encircles the chemical stream, to shield it from the surrounding flame.
  • the reaction occurs away from the burner face, which in turn prevents an undesired build-up of reactants on the burner surface, which could adversely affect performance.
  • These burners all are configured such that their faces, from which the gases and chemicals are ejected, are substantially planar.
  • the burner configurations differ from each other in several ways, including their thermal profile, the Reynolds number at which each operates optimally, the distance from the face at which the reaction occurs, and the length of the flame. Those skilled in the art will recognize the significance of these parameters in the deposition process.
  • burner configurations include: 1) ribbon burners having multiple chemical flows ports and non-circular flame configurations, 2) offset chemical tube burners, and 3) multiple flame burners configured to provide flames that exit the burner at different planes.
  • Most optical fiber preform producers use reactants that are chlorides of glass-forming materials, and one of the reaction products is hydrochloric acid.
  • the glass-forming oxide particles, or soot are collected on the deposition surface. Consequently, the deposition chamber needs to be closed, and the exhaust needs to be treated to neutralize the acid and to remove the undeposited soot particles.
  • FIG. 4 depicts a simple form of a deposition chamber for depositing a cylindrical shape.
  • the depicted chamber incorporates a stationary burner located on one side of the chamber and an exhaust port on the opposite side.
  • a chuck assembly holds the mandrel, on which soot is deposited to form a rod, in a vertical orientation.
  • a motor located above the chuck assembly rotates the mandrel, and the entire mechanism is mounted on a traverse mechanism that allows the entire length of the rod to be moved up and down across the flame and the stream of soot particles produced by the burner.
  • a layer of soot is deposited onto the rod each time the rod traverses the burner flame, and the process continues until the desired amount of glass has been deposited.
  • the rod can have a horizontal orientation, and the burner can traverse along the stationary but rotating rod to deposit soot, layer by layer.
  • the exhaust port can be stationary or can traverse in synchronism with the burner.
  • the burner can be oriented either horizontally or vertically.
  • burners described briefly above are all must be configured to provide three distinct functions: (1) generating soot, (2) providing a thermophoretic-driving force required for efficiently depositing the soot on the substrate, and (3) supplying heat to control the deposited soot density. This has limited the deposition rate that can be achieved using just a single burner. In addition, systems incorporating multiple burners are considered to require unduly complex control schemes and a much higher degree of precision in burner design.
  • thermophoretic-driving force can limit the size of the deposition surface that can be produced efficiently.
  • a thermophoretic driving force exists only if the soot stream is confined between the flame envelope and the deposition surface. Consequently, the flame length must be sufficient to completely wrap around the deposition substrate, as shown in FIG. 5.
  • the deposition rate for a given burner should generally be proportional to the rod's diameter.
  • higher average deposition rates are achieved for preforms having larger diameters.
  • the deposition rates of conventional burners increase generally linearly with diameter, as is theoretically predicted.
  • the deposition rates of such burners fail to continue increasing after the rod diameter has reached a specific value, e.g., about 12 cm.
  • Turbulence in the deposition zone can be controlled if the flame is oriented so as to impinge on the deposition surface at an angle along the rotation axis. This can improve the soot collection efficiency to about 70%, but it restricts the number of burners to only one. In addition, the flame length of this single burner can limit preform diameter.
  • One way to provide increased flame length is to use a multi-flame burner, in which two or more flames are produced concentrically around the chemical tube.
  • the first flame originates at the exit plane of the chemicals from the burner, and the other flames originate closer to the deposition target.
  • One problem with this design is that the widths of the flames increases, which creates a longer path for soot particles to travel before they deposit. The increase in flame length also is limited.
  • Another approach is to use multiple burners, separated axially along the target rod, with soot streams being directed perpendicular to the deposition surface.
  • the axial separation of the burners can increase the size of the ends of the deposition surface subject to nonuniformity.
  • the effective collection efficiency of usable soot drops to only about 30%.
  • the present invention resides in a deposition apparatus for making a glass preform by flame hydrolysis, with an improved efficiency.
  • the apparatus includes a support mandrel mounted within a deposition chamber, for rotation about a longitudinal axis, and a main deposition burner configured to direct a stream of soot-forming reactants and a stream of flame gases toward the support mandrel, so as to form by flame hydrolysis a glass preform on the mandrel.
  • One or more auxiliary burners configured to introduce a stream of flame gases, but no stream of soot-forming reactants, toward the glass preform, to heat portions of the preform not fully heated by the stream of flame gases directed by the main deposition burner.
  • a controller is configured to controllably operate the one or more auxiliary burners after the glass preform formed on the support mandrel has reached a predetermined size.
  • the auxiliary burners can be located on opposite sides of the main deposition burner, spaced circumferentially around the support mandrel.
  • the main deposition burner is configured to direct a stream of soot-forming reactants quasi-tangentially toward the glass preform being formed on the support mandrel.
  • the apparatus can further include a mount configured to withdraw the main deposition burner from the glass preform as the preform grows in size.
  • the main deposition burner includes a reactant port, aligned with a central axis, for forming the stream of soot-forming reactants, and it further includes a plurality of flame ports, arranged concentrically around the reactant port, for forming the flame concentrically around the stream of soot-forming reactants.
  • the main deposition burner can further include a first plurality of shield gas ports, arranged concentrically around the reactant port, between the reactant port and the plurality of flame ports, for forming an inner shield gas stream between the stream of soot-forming reactants and the flame, and a second plurality of shield gas ports, arranged concentrically around the reactant port, radially outward of the plurality of flame ports, for forming an outer shield gas stream radially outward of the flame.
  • the plurality of flame ports can be configured to direct the flame obliquely inwardly toward the main deposition burner's central axis.
  • These flame ports can be asymmetrically configured, such that the flame is oriented obliquely inwardly toward the main deposition burner's central axis along one transverse axis, but is oriented substantially parallel with such central axis along an orthogonal transverse axis.
  • the main deposition burner can include a central reactant port, aligned with the burner's central axis, for forming a central stream of soot-forming reactants that impinges substantially radially on the glass preform being formed on the support mandrel, and can further include a pair of supplemental reactant ports located on opposite sides of the central reactant port, for forming supplemental streams of soot-forming reactants that impinge quasi- tangentially on the glass preform.
  • a valve can control the delivery of reactant gases to the central port and to the pair of supplemental ports, according to the size of the glass preform being formed on the support mandrel.
  • the main deposition burner can be configured to burn either a mixture of oxygen and natural gas or a mixture of oxygen and hydrogen.
  • FIG. 1 is a simplified perspective view of a prior art concentric tube burner .
  • FIG. 2 is a simplified perspective view of a prior art aperture burner.
  • FIG. 3 is a simplified view of the face of a prior art combination aperture/concentric tube burner.
  • FIG. 4 is a schematic diagram of a prior art deposition system for producing a cylindrical glass preform by flame hydrolysis.
  • FIG. 5 is an end view of the prior art deposition system of FIG. 4, showing the flame wrapped around the cylindrical preform.
  • FIG. 6 is a graph depicting the relationship between target diameter and deposition rate for a typical prior art single-burner deposition system.
  • FIG. 7 is a simplified schematic drawing of one embodiment of a deposition system for producing a cylindrical glass preform by flame hydrolysis in accordance with the invention.
  • FIG. 8 is a view of the face of a first embodiment of a burner assembly in accordance with the invention.
  • FIG. 9 is a cross-sectional view of the burner assembly of FIG. 8, taken substantially in the direction of the arrows 9-9 in FIG. 8.
  • FIG. 10 is a view of the face of a second embodiment of a burner assembly in accordance with the invention, this embodiment differing from the embodiment of FIGS. 8 and 9 in that the flame is directed inwardly toward the burner's central axis.
  • FIG. 11 is a cross-sectional view of the burner assembly of FIG. 10, taken substantially in the direction of the arrows 11-11 in FIG. 10.
  • FIG. 12 is a view of the face of a third embodiment of a burner assembly in accordance with the invention, this embodiment differing from the embodiments of FIGS. 8-11 in that the flame is directed inwardly toward the burner's central axis only in the direction along the axis of the target rod.
  • FIG. 13 is a cross-sectional view of the burner assembly of FIG. 12, taken substantially in the direction of the arrows 13-13 in FIG. 12.
  • FIG. 14 is a cross-sectional view of the burner assembly of FIG. 12, taken substantially in the direction of the arrows 14-14 in FIG. 12.
  • FIG. 15 is a view of the face of a fourth embodiment of a burner assembly in accordance with the invention.
  • FIG. 16 is a view of the face of a fifth embodiment of a burner assembly in accordance with the invention.
  • the preform is formed on a starting mandrel or rod 22, which is mounted for rotation within a deposition chamber 24.
  • a main deposition burner 26 directs both a stream of soot particles 28 and an encircling flame 30 toward the rotating rod.
  • the soot particles are caused to move away from the flame and toward the rotating rod, for deposition on the rod as a thin layer.
  • the main burner is moved axially relative to the rotating rod by a carriage assembly (not shown in the drawings).
  • the glass preform thereby is built up, layer by layer, into a cylindrical shape.
  • the system further incorporates additional pairs of auxiliary burners 34a,b and 36a,b, spaced circumferentially around the rod 22 and preform 20, on opposite sides of the main burner. These auxiliary burners are controlled so as to direct flames 38 toward the preform after the preform has grown to a predetermined size.
  • the auxiliary flames 38 ensure that the substrate's entire circumference is enveloped by flame, even as the preform substrate 20 approaches its final diameter.
  • the auxiliary flames impinge obliquely on the preform, and the velocities of the flames are controlled, so as to minimize turbulence on the preform's deposition surface.
  • additional (or fewer) auxiliary burners alternatively could be used, and the relative positioning of the auxiliary burners could be modified, depending on various factors, including the lengths of the flames and the preform's anticipated final diameter.
  • the main deposition burner 26 incorporates three reactant feed tubes 40a,b,c, which generate three soot streams 42a,b,c.
  • the center feed tube 40b is oriented radially relative to the axis of the rotating rod 22 and preform 20.
  • a valve 44 controls the delivery of the reactants to the feed tubes.
  • the lateral soot streams 42a,c produced by the lateral feed tubes impinge quasi-tangentially on the deposition substrate, to reduce turbulence at the preform's deposition surface.
  • the main deposition burner 26 produces the flame 30 by directing a mixture of oxygen and natural gas or oxygen and hydrogen into a ring-shaped gas chamber 46 concentric with the center of the feed tubes 40a,b,c.
  • the gas mixture exits the gas chamber via a number of ports 48 forming a ring around the feed tubes.
  • Concentric with the gas chamber are a ring-shaped inner shield chamber 50 and a ring-shaped outer shield chamber 52, which receive a nitrogen shield gas and direct this shield gas via exit ports 54 and 56, respectively.
  • the ports that form these two shield gas streams are oriented such that the streams follow non-convergent paths that are substantially parallel with the burner's central axis.
  • the main deposition burner 26 is mounted on a carriage 58 that permits the burner to be withdrawn from the preform as the preform's diameter continues to grow. It should be understood that if the starting rod diameter is sufficiently large, the central feed tube 40b could be eliminated, leaving just the two lateral feed tubes 40a,c for producing two quasi-tangential soot streams.
  • FIGS. 10 and 11 depict an alternative embodiment of a main deposition burner 26' in accordance with the invention.
  • This burner differs from the burner 26 of FIGS. 8 and 9 in that ports 48' that produce the flame 30' and the ports 56' that produce the outer ring-shaped shield gas stream are oriented such that the two streams converge toward the central soot stream 42b.
  • This configuration provides a flame of reduced width. It is particularly useful as part of a deposition machine having multiple deposition burners spaced axially along the rotating rod and deposition substrate.
  • FIGS. 12-14 depict another alternative embodiment of a main deposition burner 26" in accordance with the invention. This burner differs from the burner 26 of FIGS. 8 and 9 and the burner 26' of FIGS. 10-11, in that it is asymmetric.
  • Ports 48" for the flame gases are oriented such that the flame 30" converges toward the burner's soot stream 42b only along one of its two orthogonal axes, i.e., the axis depicted in FIG. 13. Ordinarily, this axis would be aligned parallel with the axis of the rotating rod and deposition substrate, thereby reducing flame width along that axis.
  • the flame does not converge along the orthogonal axis (FIG. 14), but instead is oriented substantially perpendicular to the burner's face. This facilitates a quasi-tangential flow along the deposition substrate's circumference.
  • This burner configuration is particularly suitable for use in depositing soot onto substrates having a large diameter.
  • auxiliary burners 34a,b and 36a,b can have a configuration that is the same as that of the concentric tube burner or aperture burner of prior art, but without the central chemical stream.
  • the preferred burner design is the aperture burner 26 of FIGS. 8 and 9 and it formed of a suitable metallic material.
  • Surface-mixed burners also are suitable, and all of the features of this invention can be designed into surface-mixed burners.
  • the preferred burner design is a concentric tube burner constructed of glass tubes. Those skilled in the art are readily capable of designing a suitable concentric tube burner having a design according to this invention.
  • FIG. 15 depicts the face of a fourth preferred embodiment of a main deposition burner 60 in accordance with the invention.
  • the face of this burner is asymmetric; however, unlike the burner of FIGS. 12-14, this burner 60 does not incorporate ports for forming an outer shield gas stream.
  • the burner is of the chemical tube aperture type, and it is particularly suited for burning an oxygen/natural gas premix. The parameters set forth below are considered suitable for a deposition machine incorporating the burner 60 of FIG. 15.
  • Inner shield Asymmetric chamber: Minor axis - 15 mm
  • Premixed oxygen/gas Axial taper angle : 15° Minor axis width: 35 mm Major axis width: 55 mm Number of apertures rings: 2 Number of apertures: 30 to 90
  • Oxygen/natural gas 40 slpm (constant)
  • Inner shield same as oxygen/natural gas
  • Oxygen in chemical tube 1 slpm (optional)
  • Rod rotation rate 60 rpm
  • Flame orientation Vertically upward Material of construction: 316 Stainless Steel
  • Burner shield Silica tube protruding 50 mm upwardly from the burner face
  • Flow rate as needed, for density control
  • the flow of the central chemical stream is likely to exceed a Reynolds number of 2000, and the flow at the face of the burner 60 might be turbulent.
  • the velocity of this stream will decrease as it flows toward the deposition surface, and the process will remain efficient so long as the stream becomes laminar by the time it reaches the surface.
  • the auxiliary burners are operated only after the diameter of the preform has reached a predetermined value, and the heat they generate should be gradually increased as the preform diameter increases.
  • FIG. 16 depicts the face of a fifth preferred embodiment of a main deposition burner 62 in accordance with the invention.
  • the burner is asymmetric, like the burner 60 of FIG. 15, but it is of the quartz tube type. It is particularly suited for burning an oxygen/hydrogen mixture.
  • the parameters set forth below are considered suitable for a deposition machine incorporating the burner 62 of FIG. 16.
  • Inner shield as required, to prevent burner build-up
  • Oxygen in chemical tube 1 slpm (optional)
  • Rod rotation rate 60 rpm
  • Flame orientation Vertically upward Material of construction: Fused silica Burner shield: Silica tube protruding 50 mm upwardly from the burner face Burner traverse: 30 cm/m
  • Burner to deposition surface distance 15 cm, start to 5 cm diameter
  • the flow of the central chemical stream is likely to exceed a Reynolds number of 2000, and the flow at the face of the burner 62 might be turbulent.
  • the velocity of this stream will decrease as it flows toward the deposition surface, and the process will remain efficient so long as the stream becomes laminar by the time it reaches the surface.
  • the auxiliary burners are operated only after the diameter of the preform has reached a predetermined value, and the heat they generate should be gradually increased as the preform diameter increases.
  • a deposition system in accordance with the invention uses a main deposition burner that is symmetric, like the burner 26 of FIGS. 8 and 9. It is of the quartz tube type, with only two chemical tubes, each configured to produce a reactant stream having an oblique incidence on the target rod.
  • the burner is particularly suited for burning an oxygen/hydrogen mixture. Its purpose is to clad vapor phase axial deposition (VAD) cores on line.
  • VAD vapor phase axial deposition
  • Inner shield Chamber diameter: 25 mm
  • Flame hydrogen Cylindrical, diameter adjusted for proper velocity
  • Inner shield as required, to prevent burner build-up SiCl 4 : adjusted for desired t/a ratio
  • Rod rotation rate As practiced in conventional VAD Flame orientation: Inclined 15 ° upward from horizontal Material of construction: Fused silica Burner shield: Fused silica protruding at least 50 mm from burner face
  • Burner to deposition surface distance 15 cm Auxiliary burners: Number of burners: 2 Orientation: inclined 15 ° upward Distance from starting rod surface: 15 cm Distance between burner axes: 10 cm Flame width: 25 mm (approximately) Flows: flame hydrogen and oxygen Flow rate: as needed, for density control
  • the present invention provides an improved apparatus, and related method, for making a glass preform by flame hydrolysis.
  • the apparatus includes a main deposition burner configured to direct a stream of soot-forming reactants and a stream of flame gases into a deposition chamber, in a direction toward a rotating support mandrel, so as to form by flame hydrolysis a glass preform on the mandrel.
  • a pair of auxiliary burners is included, for introducing streams of flame gases, but no streams of soot-forming reactants, toward the glass preform, from opposite lateral sides of the main deposition burner; to provide additional heat when the preform has reached a predetermined size, thereby improving efficiency.

Landscapes

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

Abstract

La présente invention concerne un appareil de fabrication de préforme de verre par hydrolyse à la flamme. Cet appareil comprend un brûleur principal de dépôt agencé de façon à diriger au moins deux flux de réactifs formant de la suie et un flux de flamme de gaz dans une chambre de dépôt, en direction d'un mandrin de support rotatif, de façon à former par hydrolyse à la flamme une préforme de verre sur un mandrin. Une ou plusieurs paires de brûleurs auxiliaires peuvent aussi être incluses, de façon à introduire de nouveaux flux de flamme de gaz, mais pas de flux de réactifs formant de la suie, en direction de la préforme de verre, et en provenance des côtés latéraux opposés du brûleur principal de dépôt, et de façon à apporter de la chaleur additionnelle lorsque la préforme a atteint une taille prédéterminée, et améliorer ainsi l'efficacité. Le brûleur principal de dépôt peut être agencé de façon à diriger au moins deux des flux de réactifs formant de la suie afin d'avoir une incidence quasi tangentielle vers le mandrin et, à diriger ensuite le flux des flammes de gaz en oblique vers l'intérieur en direction des flux de réactifs formant de la suie, de façon à rétrécir la largeur de la flamme le long d'un ou des deux axes orthogonaux.
EP00959949A 1999-09-03 2000-09-01 Appareil de fabrication de preforme de verre par hydrolyse a la flamme Withdrawn EP1218300A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US15229399P 1999-09-03 1999-09-03
US152293P 1999-09-03
PCT/US2000/024456 WO2001017918A1 (fr) 1999-09-03 2000-09-01 Appareil de fabrication de preforme de verre par hydrolyse a la flamme

Publications (1)

Publication Number Publication Date
EP1218300A1 true EP1218300A1 (fr) 2002-07-03

Family

ID=22542308

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00959949A Withdrawn EP1218300A1 (fr) 1999-09-03 2000-09-01 Appareil de fabrication de preforme de verre par hydrolyse a la flamme

Country Status (6)

Country Link
EP (1) EP1218300A1 (fr)
JP (1) JP2003508336A (fr)
KR (1) KR20020029774A (fr)
CN (1) CN1367762A (fr)
AU (1) AU7117900A (fr)
WO (1) WO2001017918A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100521957B1 (ko) * 2003-07-11 2005-10-14 엘에스전선 주식회사 광섬유 제조를 위한 외부 기상 증착 장치 및 이를 이용한광섬유 모재 제조방법
JP4358088B2 (ja) * 2004-01-14 2009-11-04 株式会社フジクラ 光ファイバ用多孔質ガラス母材の製造装置
JP5748633B2 (ja) 2011-10-18 2015-07-15 信越化学工業株式会社 多孔質ガラス母材製造用バーナ及び多孔質ガラス母材の製造方法
US9540272B2 (en) 2014-05-22 2017-01-10 Corning Incorporated Burner shield to reduce soot buildup
JP6570489B2 (ja) * 2016-08-16 2019-09-04 信越化学工業株式会社 ガラス微粒子堆積体の製造装置

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS557508A (en) * 1978-06-26 1980-01-19 Nippon Telegr & Teleph Corp <Ntt> Production of focusing type optical fiber base material
GB2083806B (en) * 1980-09-11 1984-08-08 Nippon Telegraph & Telephone Fabrication methods of doped silica glass and optical fibre preform by using the doped silica glass
JPS58213647A (ja) * 1982-06-04 1983-12-12 Nippon Telegr & Teleph Corp <Ntt> 光フアイバのコア用ス−ト棒製造方法
DE3474657D1 (en) * 1984-01-31 1988-11-24 Nippon Telegraph & Telephone Method of fabricating optical fiber preforms
JPH0264036A (ja) * 1988-08-30 1990-03-05 Fujikura Ltd 光ファイバ母材の製造方法
JPH04240125A (ja) * 1991-01-16 1992-08-27 Sumitomo Electric Ind Ltd 光ファイバ用母材の製造方法
JPH05330844A (ja) * 1992-05-27 1993-12-14 Fujikura Ltd 光ファイバ母材の製造方法
JPH0672733A (ja) * 1992-08-25 1994-03-15 Furukawa Electric Co Ltd:The ガラス微粒子合成バーナ及びこれを用いた光ファイバ母材の製造方法
JP3828192B2 (ja) * 1996-02-22 2006-10-04 株式会社フジクラ 光ファイバ母材の製造方法及び光ファイバ母材製造用バーナ

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0117918A1 *

Also Published As

Publication number Publication date
WO2001017918A1 (fr) 2001-03-15
CN1367762A (zh) 2002-09-04
AU7117900A (en) 2001-04-10
KR20020029774A (ko) 2002-04-19
JP2003508336A (ja) 2003-03-04

Similar Documents

Publication Publication Date Title
EP0656326B1 (fr) Procédé de fabrication d&#39;une optique à partir d&#39;une préforme
US6253580B1 (en) Method of making a tubular member for optical fiber production using plasma outside vapor deposition
JPH039047B2 (fr)
GB2128982A (en) Fabrication method of optical fiber preforms
AU750390B2 (en) Method of making an optical fiber preform
EP0231022B1 (fr) Appareil pour la fabrication d&#39;une préforme poreuse d&#39;un fibre optique
JP4498917B2 (ja) ガラス棒状体の製造方法
RU2284968C2 (ru) Способ изготовления оптического стекла
EP1218300A1 (fr) Appareil de fabrication de preforme de verre par hydrolyse a la flamme
US20030101770A1 (en) Method and system for producing deposit of fine glass particles
EP0072069B1 (fr) Procédé de fabrication de préformes pour étirer des fibres optiques et appareil pour la fabrication en continue de fibres optiques
JP4404767B2 (ja) プラズマ補助堆積法を用いて合成石英ガラスからプリフォームを製造するための方法及び装置
US4312654A (en) Method and apparatus for making large diameter optical waveguide preforms
EP1530551A1 (fr) Procede et dispositif permettant de produire des preformes de fibres optiques au moyen d&#39;un procede de depot externe en phase vapeur
JP3567574B2 (ja) 多孔質ガラス母材合成用バーナ
JPH0463018B2 (fr)
KR100630117B1 (ko) 기상 외부 증착 방법에 의한 광섬유 모재 제작 장치
US7441416B2 (en) Method for manufacturing optical fibre preforms
EP1343731B1 (fr) Bruleur de depot a flammes multiples et procede de fabrication de preformes de fibres optiques
US20060185399A1 (en) Apparatus for fabricating optical fiber preform through external vapor deposition process
JP2000007367A (ja) 光ファイバ用ガラス母材の製造装置および製造方法
JPH09188522A (ja) ガラス微粒子合成用トーチ
JP3275428B2 (ja) ガラス母材の製造方法及び装置
JP3998228B2 (ja) 光ファイバ多孔質母材、光ファイバガラス母材並びにこれらの製造方法
EP1216967A1 (fr) Procédé de fabrication d&#39;une préforme en verre pour fibres optiques par dépôt en phase vapeur

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20020214

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20021231