Method and apparatus for producing a quartz glass cylinder
US8613207B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2009 |
| Grant date | Dec 24, 2013 |
| Priority date | — |
| Expiry date | Aug 23, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03B5/182
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In a known method for drawing a tubular quartz glass strand, SiO2-containing starting material is fed to a melting crucible, softened therein into a viscous quartz glass mass (27), and said mass is pulled vertically downward as a cylindrical quartz glass strand (5; 33) through a die (4; 34) provided in the bottom region of the melting crucible (1), said die having a gap-shaped outlet (25; 36), which is defined by a bottom opening and a die inside part, and thereafter the quartz glass cylinder is cut to length. In order to provide a method starting from this which facilitates the production of homogeneous quartz glass cylinders, even if the lateral dimensions thereof are in the range of the inside diameters of conventional melting crucibles (1), according to the invention the viscous quartz glass mass is drawn over a flow constriction (12; 32) provided in an upper region of the die (4; 34) and leading downward into the outlet (25; 36) via a flow channel, said region facing the crucible interior, wherein the outlet has an opening width that is larger than the width of the flow constriction (12; 32), and wherein a first minimum circumscribed circle around the flow constriction (12; 32…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.