Process and apparatus for the production of a quartz glass blank

US5788730A · kind A · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Klaus Ruppert · Siegen, DE
• Anton Steinkohl · Grundau, DE

Key dates

• Filing date: Jul 10, 1996
• Grant date: Aug 4, 1998
• Expiry date: Jul 10, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03B2207/70
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A silicon-containing glass starting material is fed through a central area of a multi-nozzle burner head while the fuel gases are fed through an outer area surrounding the center. In a reaction zone near the burner head, fine SiO.sub.2 soot particles are formed, which are deposited on a carrier to build up a porous soot body, which is then sintered. During the process of building up the soot body, the fuel gas stream is varied to achieve a desired radial or axial density profile in the soot body. To separate the glass starting material from the fuel gas in the area extending from the burner head to the reaction zone, a barrier gas stream is provided between the burner gas stream and the stream of glass starting material. The burner head has a central, tubular nozzle and several ring nozzles arranged coaxially around it. Between the central nozzle and the ring nozzles, a ring-shaped barrier gas nozzle is provided, which has inner and outer boundary walls which are circular in radial cross section. At least the outer boundary wall slants toward the central nozzle in an area extending from underneath the nozzle orifice to a point level with the nozzle orifice.