Patent · US Expired

Method for the production of flat, transparent vitreous silica slabs of low bubble content

US4377405A · kind A · utility

1Cited by

5References

7Claims

0Family size

Assignee

Heraeus Quarzschmelze GmbH, Quarzstrasse · DE

Inventors

Lutz Brandt · Maintal, DE
Karl Kreutzer · Leverkusen, DE
Karlheinz Rau · Hanau, DE
Horst Schmidt · Bad Endbach, DE
Fritz Simmat · Gelnhausen, DE

Key dates

Filing date	Apr 16, 1981
Grant date	Mar 22, 1983
Priority date	—
Expiry date	Apr 16, 2001

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC03B5/0334
WIPO fieldOther special machines
WIPO sectorMechanical engineering

Abstract

Flat, transparent slabs of vitreous silica of optical quality are produced by melting granular starting material in a vacuum by means of an electrical heating system. The starting material is melted while sustaining a heat flow from the top to the bottom of the crucible. The bottom of the crucible is made permeable to gases. The heat isolation power of the crucible wall increases from the bottom to the top of the crucible.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.