Heraeus Quarzglas Gmbh & Co Kg

Sven Schmidt

Udo Peper

Steffen Zwarg

Juergen Roeper

Hans-Georg Fritsche

Frank Hoff

Michael Muschler

Andreas Helm

A known method for producing a cylinder of quartz glass comprises a method step in which a porous SiObody comprising a central inner bore, a lower end and an upper end is sintered in a sintering furnace zone by zone, starting from the upper end, to obtain the quartz glass cylinder, a holding device being used by means of which the SiObody is held standing in vertical orientation during a first sintering phase and suspended in a second sintering phase. Starting therefrom, to indicate a method by means of which even heavy bodies of porous SiOcan be reliably held during sintering, it is suggested according to the invention that the holding device comprises a fusion body of quartz glass which is arranged in the area of the upper end in the inner bore and which in the course of the first sintering phase fuses with the quartz glass of the SiObody and which during the second sintering phase is in operative interaction with a holding element of the holding device and together with said element contributes to a suspended holding of the SiObody to be sintered.

Method for producing a cylinder of quartz glass using a holding device and appropriate holding device for performing the method

Method for producing a semifinished product from synthetic quartz glass Methods for producing a semifinished product from synthetic quartz glass by plastic deformation of a softened SiOmass in a melt mold are known. Starting from this, to avoid fusion defects as much as possible and to obtain semifinished products of quartz glass in a reproducibly high quality, a method is suggested that comprises the following steps: (a) providing a porous SiOsoot body, (b) zonewise sintering of the SiOsoot body in the melt mold at a sintering temperature and during a sintering period with formation of a completely sintered transparent quartz glass body, and directly thereafter (c) shaping the sintered quartz glass body by softening in the melt mold with formation of a viscous quartz glass mass which fills the volume of the melt mold entirely or partly, and (d) cooling the quartz glass mass and removing the mass from the melt mold with formation of the semifinished product.

Method for producing a semifinished product from synthetic quartz glass

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Zorbig, Germany

Sven Schmidt