Heraeus Quarzglas Gmbh & Co Kg

Heraeus Quartz North America LLC

Heraeus Tenevo Gmbh

Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Oliver Ganz

Martin Trommer

Thomas Bogdahn

Harald Hain

Ralph Sattmann

Jan Vydra

Manuel Rosenberger

Kai Huei Chang

Kay Schuster

Clemens Schmitt

James E Beavers, Jr

Steffen Weimann

Georges Levon Fattal

Norbert Cibis

Peter Bauer

Rene Sowa

Oliver Humbach

Thomas Bernard

Eric Emmert

Frank G&auml;nsicke

Tim Alan Pontsler

Kenneth Robert Koch

Michael HÜNERMANN

An apparatus and related process for producing a high-strength weld between two glass components. Chucks clamp and move respective first ends of the glass components toward each other inside an enclosure, where the second ends are heated, softened, and welded together in a weld zone. The enclosure has layers of stacked quartz glass bricks and allows the weld zone to cool slowly and avoid stress. A propane quartz melting torch directs a flame inside the enclosure and toward the second ends as the glass components move toward each other. The flame softens the second ends and creates substantially smooth polished surfaces in the weld zone having an increased hydroxide content. At least 80% of the weld zone has a hydroxide content greater than about 10 ppm average in a 10 &#x3bc;m depth from the surface and the tensile strength of the weld zone is above about 10 MPa.

High-strength welding process for making heavy glass preforms with large cross sectional areas

Known heating burners for producing a welded joint between components of quartz glass include a burner head in which at least one burner nozzle is formed, a burner-head cooling system for the temperature control of the burner head and a supply line connected to the burner nozzle for a fuel gas. Starting from this, to modify a heating burner in such a way that impurities in the weld seam between quartz-glass components to be connected are largely avoided, it is suggested that the burner head should include a base body of silver or of a silver-based alloy.

Heating burner for producing an integral bond between components of quartz glass

Method for producing an integral bond between components of quartz glass and heating burner suited therefor

Apparatus and method for producing elongated glass components with low bow. The apparatus may include a heating element to heat a bulk glass component where a strand may be drawn from the bulk glass component in a downward direction and a gripper device including a clamping element to support the strand while pulling or drawing it from the bulk glass component in a linear motion, and a low-friction mounting element attached to the clamping element which allows translational movement of the clamping element in an x-y plane. The gripper device may further be used to reduce bow in the strand while it is being drawn by moving the clamping element on the mounting element in a direction opposite the direction of any measured transverse acceleration.

Formation of elongated glass components with low bow using a gripper device

A method for producing substrate tubes of quartz glass includes continuously supplying a hollow cylinder of quartz glass to a heating zone, softening the hollow cylinder zonewise in the heating zone, and drawing off a tubular strand from the softened portion. The hollow cylinder has an outer diameter C, an inner diameter Cand an inner bore. The tubular strand has an outer diameter Tand an inner diameter T. The following parameters are applicable to the hollow cylinder and the tubular strand: C&#x3e;180 mm, C&#x3e;3 with C=C/C, T&#x3c;1.6 with T=T/Tand C/T&#x3c;2.5. The blow pressure in an inner bore is adjusted to a value in the range of 4 to 10 mbar. Substrate tubes, obtained by cutting the tubular strand to the desired length, serve as semi-finished products for the manufacture of preforms for optical fibers.

Method for producing a substrate tube of quartz glass

A method for using a temperature control loop in order to further develop process control during elongation of a cylindrical preform such that a component strand with high dimensional accuracy can be drawn even in the presence of temperature-effective defects during the elongation process: (a) the continuous measurement of a first temperature value, T, at an upper measuring point on the surface of the cylindrical preform; (b) the continuous measurement of a second temperature value, T, at a lower measuring point; (c) calculation of a temperature distribution in the region between the measuring points Tand T, and determination of a modelled deformation temperature, T, using an algorithmic model taking with first and the second temperature values as model input parameters, and the modelled deformation temperature, T, as a regulating variable and the heating-zone temperature Tas a manipulated variable for the temperature-control loop.

Process for producing a cylindrical component made of glass by elongation

A method of manufacturing an optical fiber preform or an optical fiber is provided. The method includes the steps of: (a) providing a glass tube and a glass core rod; (b) inserting the glass core rod into the glass tube to form an assembled body; (c) heating the assembled body to cause the glass tube to collapse on and adhere to the glass core rod; and (d) treating an interface gap between the glass core rod and the glass tube during heating of at least a portion of the assembled body. Treating of the interface gap involves: (i) establishing a vacuum pressure in the interface gap, (ii) increasing a pressure of the interface gap by a treatment gas through the interface gap for a predetermined time, and (iii) re-establishing a vacuum pressure in the interface gap after the predetermined time has elapsed.

System and method for fabricating optical fiber preform and optical fiber

The present invention refers to a drawing method for producing cylindrical components of quartz glass in that a quartz glass strand is drawn off in the direction of a drawing axis from a shaping zone of soft quartz glass mass and sections having a cutting length are separated from the quartz glass strand, and the cylindrical components are produced from the sections.

Drawing method for producing cylindrical-shaped components from quartz glass

According to a known vertical drawing method for producing a cylindrical glass body, the cylinder longitudinal axis of the glass cylinder is adjusted by hand in relation to the longitudinal axis of a heating tube. The aim of the invention is to optimize the stability of said glass body. Said aim is achieved, whereby adjustment comprises the steps of detecting a value for a first radial x-y position of the cylinder longitudinal axis () of the glass cylinder () in a first horizontal detection plane (E), drawing the glass cylinder (), placed in the first x-y position, to form a test glass strand (), measuring an actual state of a radial circular, or annular dimension of the test glass strand, determining a deviation between the actual state and a set state of said circular, or annular dimension with regard to the size and position thereof, while considering the position of the glass cylinder () in relation to the inner wall of the heating tube () during drawing, calculating a corrected x-y position of the cylinder longitudinal axis () by means of a correction factor (K), the value and position of the deviation, arranging the glass cylinder () into the heating tube (), so that the cylinder longitudinal axis () extends at least in the first horizontal detection plane (E) in the x-y position and drawing the glass cylinder (), arranged in the corrected x-y position, to form another test glass strand ().

Vertical drawing method for producing a cylindrical glass body and device for carrying out said method

In a known method for producing tubes of quartz glass, a hollow cylinder () of quartz glass is continuously supplied to a heating zone () and is softened therein in regions, and a tube strand () is drawn off at a drawing speed from the softened region with formation of a drawing bulb (), and the tubes to be produced are cut to length in the form of tube strand pieces by separating the tube strand () at a desired separation point (T, Vu, Vo) and an internal pressure differing from the external pressure applied to the outer cladding is maintained in the inner bore () of the hollow cylinder () in that the inner bore () of the tube strand is provided with a flow obstacle. Starting therefrom to indicate a simple method which permits the manufacture of particularly large volume quartz glass tubes with utmost precision, while observing narrow tolerances, it is suggested according to the invention that the flow obstacle should be configured as a constriction () of the inner bore which is produced by softening and plastic deformation of the tube strand in the area of a deformation zone (Vu, Vo).

Method for producing tubes of quartz glass

The production of an optical component from quartz glass, by elongation of a coaxial arrangement of a core rod and a hollow cylinder of a given length, is known. The arrangement is thus introduced into a heating zone with a vertical orientation, such that the lower end begins to partly soften and the component is drawn downwards from the softened part. The hollow cylinder has an inner passage, provided with a restriction in the region of the lower end thereof, on which the core rod is supported. Several methods are disclosed for formation of the restriction in which the inner passage () is mechanically machined to a final dimension and, in one version of the method, the restriction in the inner passage () is generated by means of softening the lower end face of the hollow cylinder, swaged against a tool and thus folded inwards with formation of a peripheral bead ring.

Method for production of an optical component made from quartz glass

In a known method for producing a cylindrical glass body in a vertical drawing process, a glass blank is softened in a heating zone and drawn off as a glass strand by means of a draw-off device at a controlled drawing speed, the draw-off device comprising a first draw-off unit with rolling bodies rolling on the glass strand and being distributed around the circumference thereof, the rolling bodies being formed by a reference rolling body and at least one auxiliary rolling body, the drawing speed being controlled via the speed of the reference rolling body. Starting therefrom, in order to reduce damage to the surface of the glass strand caused by the draw-off device and to avoid deformations caused by existing bends of the glass strand, it is suggested according to the invention that a value for the torque of the reference rolling body () should be determined in dependence upon the weight of the drawn-off glass strand (), and that the determined value should be used as a setpoint torque for setting the torque in the at least one auxiliary rolling body ().

Method and device for producing a cylindrical glass body

A resistance furnace has a tubular heating element with a vertically-oriented longitudinal axis. The heating element has a shell surface defined by an upper side and a lower side and surrounding a furnace chamber. The heating element is connected to at least two supply terminals by which heating current is introduced at power supply points into the heating element. The supply terminals include a surrounding upper annular collar adjacent the upper side of the shell surface, and also a surrounding lower annular collar adjacent the lower side of the shell surface.

Resistance furnace with tubular heating element

In a known method for the manufacture of a tube made of a vitreous material, especially of quartz glass, a hollow cylindrical semifinished product made of a vitreous material is carried essentially vertically to a heating zone, wherein it is heated and drawn off downwards&mdash;without the use of tools&mdash;to the tube by forming a transitional area from semifinished product to tube, while diameter and wall thickness of the tube are continuously measured, and the tube's measured geometrical data being used to generate a control signal with the aid of which a pressure difference is regulated between pressure P in the interior space of the semifinished product, the transitional area and the tube, as well as pressure P in the heating chamber which is regulated in the heating zone at least in the transitional area from semifinished product to tube and its adjacent tube area. This method is to be developed further so as to enable the processing of a broader spectrum of hollow cylindrical semifinished products to tubes with the desired inside and outside dimensions. This task is solved according to the invention such that for the manufacture of tubes with the ratio of their outside diameter (D ) to their inside diameter (D ) being greater than the ratio of the outside diameter (D ) to the inside diameter (D ) of the semifinished product&mdash;pressure P in the inside space of the semifinished product, the transitional area and the tube being kept at a value which is smaller than the value of pressure P in the heating chamber, with pressure P being maintained by means of a suction (vacuum) pump.

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Bruchkoebel, Germany

Oliver Ganz