Patents Assigned to Heraeus Quarzschmelze GmbH, Quarzstrasse
  • Method for the production of flat, transparent vitreous silica slabs of low bubble content
    Patent number: 4377405
    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.
    Type: Grant
    Filed: April 16, 1981
    Date of Patent: March 22, 1983
    Assignee: Heraeus Quarzschmelze GmbH, Quarzstrasse
    Inventors: Lutz Brandt, Karl Kreutzer, Karlheinz Rau, Horst Schmidt, Fritz Simmat