Heraeus Quarzglas Gmbh

Heraeus Quarzglas Gmbh & Co Kg

Other

Shin-etsu Quartz Products Co., Ltd.

Heraeus Quarzschmelze Gmbh

Heraeus Quarschmelze Gmbh

Helmut Leber

Nigel Robert Whippey

Klaus Reimann

Poul E Breidenbach

Heinz Herzog

Jurgen Pottker

Rainer Berg

Martin Trommer

Waltraud Werdecker

Fritz Simmat

Wolfgang Englisch

Johann Leist

Juergen Weber

Hartwig Schaper

Udo Gertig

Dietmar Hellmann

Norbert Traeger

Gerhart Vilsmeier

Norbert Treber

Joerg Becker

Bernhard Franz

In a known method for drawing a tubular quartz glass strand, SiO-containing starting material is fed to a melting crucible, softened therein into a viscous quartz glass mass (), and said mass is pulled vertically downward as a cylindrical quartz glass strand () through a die () provided in the bottom region of the melting crucible (), said die having a gap-shaped outlet (), which is defined by a bottom opening and a die inside part, and thereafter the quartz glass cylinder is cut to length. In order to provide a method starting from this which facilitates the production of homogeneous quartz glass cylinders, even if the lateral dimensions thereof are in the range of the inside diameters of conventional melting crucibles (), according to the invention the viscous quartz glass mass is drawn over a flow constriction () provided in an upper region of the die () and leading downward into the outlet () via a flow channel, said region facing the crucible interior, wherein the outlet has an opening width that is larger than the width of the flow constriction (), and wherein a first minimum circumscribed circle around the flow constriction () has a diameter that is a maximum of 30% of the diameter of a second minimum circumscribed circle around the quartz glass strand () to be drawn. The invention further relates to a corresponding apparatus.

Method and apparatus for producing a quartz glass cylinder

In a known method for coating a crucible for use at a high working temperature in a crucible drawing method for quartz glass, a base body wall of tungsten has applied thereto a protective layer containing a coating metal consisting of the group selected from iridium, rhenium, osmium and ruthenium. Starting therefrom, to provide a method for producing such a component exhibiting high corrosion resistance to the quartz glass melt at low material costs, it is suggested according to the invention that the protective layer should be produced from a layer material which contains tungsten and the coating metal, and in which the amount of the coating metal should be dimensioned such that it exceeds the limit amount of a coating metal-rich phase boundary of a solid mixture phase of tungsten and the coating metal, with the solid mixture phase being thermodynamically stable at the working temperature, by not more than 25 at. % (based on the total amount of tungsten and the coating metal in the layer material).

Method for coating a component for use in a crucible drawing method for quartz glass, and coated component obtained according to the method

A process for manufacture of a component made of opaque synthetic quartz glass, and a quartz glass tube manufactured according to said process. The process comprises (i) providing a starting material in the form of granulated material of highly pure, synthetic SiO comprising at least partially porous agglomerates of SiO primary particles, the granulated material having a compacted bulk density of no less than 0.8 g/cm , (ii) filling the granulated material into a mold and converting it to an opaque quartz glass preform through a process of melting, and (iii) reshaping the preform in a heat reshaping process to obtain a component made of opaque quartz glass. A quartz glass tube is made of quartz glass consisting of a granulated material of synthetic SiO with a lithium content of no more than 100 wt-ppb, and the wall thickness of said component being in the range of 0.5 mm to 15 mm.

Process for manufacture of a component made of opaque synthetic quartz glass

A preferred embodiment of the present invention comprises a vitreous quartz pipe or container having a connector including a flange formed from at least one strip or rod-shaped piece of transparent quartz glass which is wound circumferentially around either an inner or outer surface of a portion of the pipe or container and secured to the pipe or container to thereby form a closed-ring flange. The portion of the pipe or container having the attached flange may be an open end of the pipe or container or may be a wall portion where a connector for mounting to fixtures or other fittings may be desired. This type of strip or rod-shaped piece of quartz glass can be made via a conventional pulling technique such that a strip or rod having the appropriate uniform cross-sectional shape is obtained. The prepared strips or rod-shaped pieces are then easily cut with a saw device to appropriate lengths. According to a preferred method of the present invention, a small portion of a strip or rod-shaped piece of transparent quartz glass is made pliable with the direct application of heat. As the portion of the strip or rod-shaped piece of quartz glass becomes pliable, the strip or rod-shaped piece of quartz glass is made to conform to the curvature of the underlying inner or outer pipe or container surface. At the same time, heat is applied to the pipe or container surface and the facing underside of the strip or rod-shaped piece of quartz glass and light pressure forms a secure weld between the pipe or container surface and the strip or rod-shaped piece of quartz glass. To achieve a flange having a radial depth greater than the corresponding dimensional thickness of a single prepared strip or rod-shaped piece of quartz glass, multiple layers of the strip or rod-shaped piece of quartz glass may be applied one upon the other extending radially from the surface of the pipe or container.

Methods and apparatus for providing quartz glass connectors

A preferred embodiment of the present invention comprises a vitreous quartz pipe or container having a connector including a flange formed from at least one strip or rod-shaped piece of transparent quartz glass which is wound circumferentially around either an inner or outer surface of a portion of the pipe or container and secured to the pipe or container to thereby form a closed-ring flange. The portion of the pipe or container having the attached flange may be an open end of the pipe or container or may be a wall portion where a connector for mounting to fixtures or other fittings may be desired. This type of strip or rod-shaped piece of quartz glass can be made via a conventional pulling technique such that a strip or rod having the appropriate uniform cross-sectional shape is obtained. The prepared strips or rod-shaped pieces are then easily cut with a saw device to appropriate lengths. According to a preferred method of the present invention, a small portion of a strip or rod-shaped piece of transparent quartz glass is made pliable with the direct application of heat. As the portion of the strip or rod-shaped piece of quartz glass becomes pliable, the strip or rod-shaped piece of quartz glass is made to conform to the curvature of the underlying inner or outer pipe or container surface.

Quartz glass component having a coating with a silicon carbide surface includes a gradient layer of silicon carbide and at least one additional constituent which is less hard and has a lower modulus of elasticity than silicon carbide and whose concentration decreases across the thickness of the layer from inside to outside. The coated component has good thermal-shock resistance and long-term stability in terms of its chemical resistance to hydrofluoric acid and nitric acid as well as to a mixture of these two acids.

Coated quartz glass component

Starting from a process for producing a rod-like preform, in particular for optical fibers, in which a tubular blank whose refractive index changes, viewed in the radial direction is fed to a heating zone, is softened there, and in the softened state is shaped to give the preform, a method is described for producing preforms which are hyperpure and low in defects, in which the blank used is one whose refractive index decreases, viewed in the radial direction, from the outside inwards, starting from at least one interface which is at a sufficient distance from the outer surface of the blank, of which that part which has been softened in the heating zone is introverted apart from an outer skin, and by which the preform is formed in the longitudinal axis of the tubular blank, counter to the direction in which the latter is fed to the heating zone, and in which the remaining outer skin is drawn off as a rod in the feed direction of the blank.

Method of partially introverting a multiple layer tube to form an

A method for producing an elongated composite glass body by melting at least two starting materials of different material compositions, feeding the starting materials to a drawing die disposed at the bottom of an externally heated melting crucible, and continuously drawing the melts vertically out of the drawing die to form a composite body laminated transverse to the drawing direction. To provide an interface free from impurities between the starting materials in the composite body and to enable the path of the interface to be freely shaped, the starting materials are fed in particle form continuously to a single melting crucible and heaped therein to form a preformed body in which one starting material lies directly next to the other starting material forming an interface line therebetween that extends substantially vertically and parallel to the drawing direction.

Method for producing a composite glass body with drawing of concentric

A process is known for the tool-free reshaping of a tubular hollow body of amorphous, especially vitreous material to a rod by pressure constriction wherein a pressure depression below atmospheric pressure is sustained in the tubular part by continual evacuation during the constriction, while the hollow body is continually fed horizontally, at a given speed of rotation, to a heating zone, and there its viscosity is so lowered that, as a result of the pressure difference between the absolute value of pressure below atmospheric pressure in the hollow body and the external pressure acting on the hollow body, the hollow body becomes constricted to form a rod in the closing zone and the rod is continually pulled from the closing zone at a given rotatory speed; in order by such a process to produce homogeneous, rod-shaped bodies from hollow bodies in a single procedure and at reasonable cost, the outside dimensions and inside dimensions of the hollow body, the viscosity of the vitreous material in the closing zone, the pressure difference between the absolute value of pressure below atmospheric pressure in the hollow body and the external pressure, the level of the pressure constriction, the rate of withdrawal of the rod and the rate of feed of the hollow body, as well as the rotatory speeds of the rod and hollow body, are selected such that a spur of smaller cross-sectional dimensions than those of the rod is formed in the axis of the hollow body from the closing zone in a direction contrary to the direction of withdrawal of the rod.

Method for the tool-free reshapingof a tubular body

Granular silicon dioxide is placed in a treatment chamber which is heated to a temperature ranging from 700.degree. to 1300.degree. C. The chamber is then rotated for a prescribed period of time to mix the grains while a gaseous atmosphere of chlorine and/or hydrogen chloride is passed through the treatment chamber. The mixing period is followed by a resting period which is at least ten times longer than the mixing time. During the resting period the grains are exposed to a constant electric field having a strength of 600 to 1350 V/cm applied across the chamber. The foregoing cycle is repeated several times. For working the process a device is used which includes a quartz glass rotary tube into which hollow silicon carbide electrodes extend.

Process for the purification of granular silicon dioxide

A method for the continuous production of a tube or rod of vitreous fused silica. Silicon dioxide in particle form is heated in a crucible to the softening temperature and is withdrawn contiuously downward from a bottom outlet opening in which a shaping tool is disposed. In the annular space between the shaping tool and the bottom outlet opening the softened silicon dioxide is subjected to an electrical field. In the closed crucible, a hydrogen-containing atmosphere with a hydrogen content of at least 80% is sustained above the silicon dioxide and in the space underneath the crucible that adjoins the shaping region.

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Hanau, Germany

Helmut Leber