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:
Jun. 13, 2017
Filed:
Aug. 20, 2014
Schott Ag, Mainz, DE;
Frank-Thomas Lentes, Bingen, DE;
Karin Naumann, Ober-Olm, DE;
Ulrich Schiffner, Mainz, DE;
Friedrich Siebers, Nierstein, DE;
Christian Mueller, Mainz, DE;
Klaus Schoenberger, Mainz, DE;
Evelin Weiss, Mainz, DE;
SCHOTT AG, Mainz, DE;
Abstract
A method for producing bubble-free glasses is provided, in which a glass mixture that is arsenic-free, antimony-free and tin-free with the exception of any unavoidable raw material impurities and at least one sulfate compound as a refining agent are used. The glass mixture and refining agent are melted and primarily refined in a first region of a melting tank, an average melting temperature (T1) is set at T1>1580° C. and an average melt residence time (t1) is set at t1>2 hours. A secondary refinement is carried out in a second region, an average melting temperature (T2) is set at T2>1660° C. and an average melt residence time (t2) is set at t2>1 hour, and the proportion of the SOresulting from decomposition of the sulfate is reduced to less than 0.002 wt. %.