Heraeus Quarzglas Gmbh

Heraeus Tenevo Gmbh

Heraeus Quarzglas Gmbh & Co Kg

Rainer Köppler

Heinz Fabian

Wolfgang Englisch

Uwe Christiansen

Clemens Schmitt

Bruno Uebbing

Karsten Bräuer

Bodo Kühn

Ralf Takke

Fritz-Ulrich Kreis

Klaus Arnold

According to a prior art method for producing a cylindrical component comprised of silica glass, a cylinder comprised of a softened silica glass mass is drawn in a predetermined drawing direction along a drawing axis by means of a drawing device which acts upon said cylinder. The aim of the invention is to provide a method which prevents, to the greatest possible extent, warping of the drawn cylinder and other deviations from the ideal cylinder dimensions and to prevent, to the greatest possible extent, the outer surface of the drawn cylinder from being touched. To these ends, the invention provides that the drawing device comprises a plurality of guide elements which are arranged one behind the other along the drawing axis, and which can be displaced independently of one another in a drawing direction and in a direction opposite thereto. At least two of said guide elements which maintain an engaging distance from one another are simultaneously displaced, in a frictionally engaged manner, on the cylinder in a drawing direction and with an identical drawing speed. A device suited for carrying out the inventive method comprises a feed device, a heating zone and a drawing device by means of which a cylinder is drawn along a drawing axis and in a predetermined drawing direction with a controlled drawing speed. The drawing device comprises a number of drawing elements which are arranged one behind the other along the drawing axis and which can be displaced independently of one another in a drawing direction and in a direction opposite thereto.

Method for elongating a cylinder of silica glass

A method is provided for the manufacture of SiO.sub.2 granular material. Silicic acid is dispersed in a liquid to form a dispersion. The dispersion is stirred in a stirring tank with formation of a homogeneous liquid phase. The homogeneous liquid phase is maintained by stirring at a substantially constant rate until the granular mass develops, when the solids content of the dispersion is within the range of 65 to 80 weight percent. Moisture is gradually extracted to form a granular mass which is dried and sintered.

Method for the manufacture of SiO.sub.2 granular material

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Seligenstadt, Germany

Rainer Köppler