Process for manufacturing quartz glass pipes having a high content of silica with only minor diameter deviations

US5026413A · kind A · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Helmut Lebert · Hanau, DE
• Nigel Whippey · Seligenstadt, DE

Key dates

• Filing date: Apr 17, 1990
• Grant date: Jun 25, 1991
• Expiry date: Apr 17, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03B33/06
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

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A process is described for manufacturing vertically withdrawn pipes from quartz glass or glasses having a high content of silica with only minor diameter deviation.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 A pipe is formed in a deformation zone and is downwardly withdrawn.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a higher pressure in the pipe interior as opposed to the pressure in the chamber and/or the heating chamber, the withdrawn pipe end of the pipe to be manufactured is sealed.