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. 27, 1989
Filed:
Mar. 02, 1988
Karl Kreutzer, Gelnhausen, DE;
Fritz Simmat, Gelnhausen, DE;
Anton Steinkohl, Grundau, DE;
Wolfgang Englisch, Kelkheim, DE;
Heraeus Quarzschmelze GmbH, Quarzstrabe, DE;
Abstract
A method of vitrifying a porous cylindrical article made out of glass soot, especially for manufacturing a preliminary blank for optical fibers. The article is heat-treated in a furnace in a vacuum or in an atmosphere that contains helium. The porous article is placed in a horizontal graphite tube in the furnace, is sintered therein for 20 to 40 minutes in a vacuum or in a helium atmosphere with reduced pressure at 1250.degree. to 1400.degree. C., and is subsequently vitrified by heat-treating the sintered article at first in the sintering atmosphere, while slowly rotating it in the hot graphite tube for 20 to 40 minutes at approximately 1450.degree. to 1600.degree. C. and then while rotating it in the graphite tube more rapidly than in the first stage for 10 to 30 minutes at approximately 1650.degree. to 1750.degree. C.