Heraeus Quarzglas Gmbh & Co Kg

Norbert Cibis

Oliver Ganz

Jan Vydra

Ralph Sattmann

Clemens Schmitt

Peter Bauer

Rene Sowa

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

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Kahl, Germany

Norbert Cibis