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:
Mar. 01, 1977
Filed:
Jun. 16, 1975
Herbert Schul, Hanau am Main, DT;
Heraeus-Schott Quarzschmelze GmbH, Hanua am Main, DT;
Abstract
Tubes of transparent, translucent or opaque fused silica are made by heating a hollow cylindrical blank in a drawing zone, drawing the blank from the zone while maintaining its interior under pressure and rotating same about its longitudinal axis, and calibrating the still-plastic tube immediately upon leaving the drawing zone in a calibration zone defined by two graphite plates. Apparatus for carrying out the method includes means for heating the blank to a drawing temperature in a drawing zone, means for drawing the blank from the zone, means for maintaining the interior of the blank under pressure and means for rotating the blank as it is drawn, and calibrating means for calibrating the still-plastic tube immediately upon leaving the drawing zone including two graphite plate means disposed on metal plates through which a coolant can flow.