METHOD FOR CONTINUOUSLY MAKING TUBES OR RODS FROM QUARTZ GLASS

摘要

In the process, particulate silicon dioxide is heated to the softening point in a crucible and withdrawn continuously downward from a base outlet aperture in which a mould is arranged. In the annular space between the mould and the base outlet aperture, the softened silicon dioxide is subjected to an electrical field. In crucibles sealed to the outside, a hydrogen-containing atmosphere having a hydrogen content of at least 80 % is maintained above the silicon dioxide and in the space following the moulding zone below the crucible.