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. 25, 1991
Filed:
Apr. 17, 1990
Helmut Lebert, Hanau, DE;
Nigel R Whippey, Seligenstadt, DE;
Heraeus Quarzglas GmbH, Hanau, DE;
Abstract
A process is described for manufacturing vertically withdrawn pipes from quartz glass or glasses having a high content of silica with only minor diameter deviation. In an electrically heated furnace, the initial material is heated up to the softening point. A pipe is formed in a deformation zone and is downwardly withdrawn. In this deformation zone, a constant pressure difference is maintained between the pressure in the pipe interior and the pressure in a chamber and/or heating chamber. The pressure is continuously measured and controlled so as to be at a constant difference. In order to maintain a higher pressure in the pipe interior as opposed to the pressure in the chamber and/or the heating chamber, the withdrawn pipe end of the pipe to be manufactured is sealed.