Heraeus Quarzschmelze Gmbh

Heraeus Quarzglas Gmbh

Heraeus Quarzglas Gmbh & Co Kg

Heraeus Quartzglas Gmbh

Anton Steinkohl

Uwe Christiansen

Klaus Ruppert

Fritz Simmat

Karlheinz Rau

Klaus Dittmer

Wolfgang Englisch

Albert Muhlich

Ralf Takke

Karl Kreutzer

Bruno Streb

Hans-Ulrich Bonewitz

Dieter Ross

Karl-Friedrich Klein

Wolfgang Ruffing

In a known method, a quartz glass preform is produced by supplying a glass-forming base material in liquid form to an injection nozzle of a multi-nozzle flame deposition burner, vaporizing or gasifying the liquid glass-forming base material in the deposition burner, mixing the vaporized or gasified glass-forming base material with a gas containing oxygen under creation of SiO.sub.2 particles in a chemical reaction, deposition of the SiO.sub.2 particles on a substrate under creation of a porous preform and sintering of the preform. In this method, expensive devices such as pumps and ultrasonic vaporizers are needed for the vaporization of the liquid glass-forming base material; in addition, these devices are subject to mechanical wear and chemical attack and furthermore, they require extensive maintenance and due to their size result in a great height of construction. In order to avoid these disadvantages, a method is proposed according to the invention wherein a gas for the creation of a mist is fed to the deposition burner for the vaporization or gasification of the glass-forming base material, resulting in the creation of a low pressure in the area of the injection nozzle orifice. In an apparatus suitable for implementing the method, a vaporizing device comprises a vaporizing nozzle for the supply of a vaporizing gas, said nozzle being located adjacent to the injection nozzle and having an opening which, as seen in the direction of travel of the vaporizing gas, extends in a plane behind the injection nozzle opening.

Method for the production of a quartz glass blank and apparatus suitable

A silicon-containing glass starting material is fed through a central area of a multi-nozzle burner head while the fuel gases are fed through an outer area surrounding the center. In a reaction zone near the burner head, fine SiO.sub.2 soot particles are formed, which are deposited on a carrier to build up a porous soot body, which is then sintered. During the process of building up the soot body, the fuel gas stream is varied to achieve a desired radial or axial density profile in the soot body. To separate the glass starting material from the fuel gas in the area extending from the burner head to the reaction zone, a barrier gas stream is provided between the burner gas stream and the stream of glass starting material. The burner head has a central, tubular nozzle and several ring nozzles arranged coaxially around it. Between the central nozzle and the ring nozzles, a ring-shaped barrier gas nozzle is provided, which has inner and outer boundary walls which are circular in radial cross section. At least the outer boundary wall slants toward the central nozzle in an area extending from underneath the nozzle orifice to a point level with the nozzle orifice.

Process and apparatus for the production of a quartz glass blank

A hollow cylinder is held in a vertical orientation and sent continuously through a heating zone for sintering. In a first phase of the sintering operation, the hollow cylinder stands on a support while the upper end (12) of the cylinder is being sintered. In a second phase the cylinder hangs from a hanging element while its lower end (10) is sintered. A vertical rod is fixed to the base on which the lower end is supported, and extends through the hollow cylinder. A retaining ring is fixed inside the upper end of the hollow cylinder. During the first phase, the upper end vitrifies and contracts so that the retaining ring engages the vertical rod. Longitudinal contraction causes the lower end to lift off the base so that the cylinder is suspended during the second phase.

Apparatus for holding a hollow cylinder of silicon dioxide soot

A layer of quartz glass soot is deposited continuously on a substrate consisting of quartz glass grains with a lower degree of sintering activity than the quartz glass soot and the soot is sintered by passing it continuously through a heating zone to form a quartz glass strip which is severed to form plates. Apparatus for implementing the process includes a conveyor suitable for the transport of quartz glass grains; a loading device for the deposition of the quartz glass grains onto the conveyor; nozzles for depositing a layer of synthetic quartz glass soot on the quartz glass grains; and a heating unit to heat the layer.

Method for manufacture of quartz glass plates

Process for the sintering of hollow cylinders of silicon dioxide soot

A method of vitrifying a porous cylindrical article made out of glass soot, especially for manufacturing a preliminary blank for optical fibers. The article is heat-treated in a furnace in a vacuum or in an atmosphere that contains helium. The porous article is placed in a horizontal graphite tube in the furnace, is sintered therein for 20 to 40 minutes in a vacuum or in a helium atmosphere with reduced pressure at 1250.degree. to 1400.degree. C., and is subsequently vitrified by heat-treating the sintered article at first in the sintering atmosphere, while slowly rotating it in the hot graphite tube for 20 to 40 minutes at approximately 1450.degree. to 1600.degree. C. and then while rotating it in the graphite tube more rapidly than in the first stage for 10 to 30 minutes at approximately 1650.degree. to 1750.degree. C.

Method of verifying a porous article made out of glass soot and furnace

Disclosed is a method for the axial building up, in a vertical arrangement, of a hollow cylindrical soot body having no internal support and consisting substantially of silicon dioxide by means of at least one flame hydrolysis build-up burner serving for the soot production. In this method the soot is deposited at the beginning of the build-up onto an auxiliary body, and during the build-up the build-up burner and the growing soot body are rotated relative to one another, and the burner is at the same time held at an unvarying distance from the growing end of the hollow cylinder and centrally above the predetermined cross section of the upwardly growing end of the cylinder wall. The penetration of soot into the interior of the cylinder is prevented by means of a directed gas stream.

Method for the continuous building of a hollow cylindrical soot body

A light-weight mirror for astronomical purposes is disclosed. The mirror consists of a mirror plate, a back plate and a supporting framework disposed between them and consisting of a plurality of rows of tubes. The rows of tubes are staggered one from the other. Each tube in a row has a line or strip of contact with two adjacently disposed tubes of the next row. The tubes are welded together along the contact line or strip. The thickness of the tube wall is reduced in the area of the contact line or strip.

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Grundau, Germany

Anton Steinkohl