The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 2004
Filed:
Aug. 16, 2001
Waltraud Werdecker, Hanau, DE;
Johann Leist, Altenstadt, DE;
Heraeus Quarzglas GmbH & Co. KG, Hanau, DE;
Abstract
In order to provide a quartz glass crucible distinguished by high purity, high opacity and/or low transmissibility in the IR spectrum, it is proposed on the basis of a known quartz glass crucible of opaque quartz glass with a crucible body symmetrical in relation to a rotational axis, an outer zone ( ) of opaque quartz glass transitioning radially toward the inside into an inner zone ( ) of transparent quartz glass and with a density of at least 2.15 g/cm , that according to the invention, the crucible body ( ) be made of a synthetic SiO granulate with a specific BET surface ranging from 0.5 m /g to 40 m /g, a tamped volume of at least 0.8 g/cm and produced from at least partially porous agglomerates of SiO primary particles. A process for producing a quartz glass crucible of this kind is distinguished according to the invention in that for the production of the crucible a SiO granulate is used which was formed from at least partially porous agglomerates of synthetically manufactured SiO primary particles and that it has a specific BET surface ranging from 0.5 m /g to 40 m /g and a tamped volume of at least 0.8 g/cm , the heating effected in such a way that a vitrification front advances from the inside outward while an inner zone ( ) of transparent quartz glass is being formed.