FABRICATION OF HEAVY WALLED SILICA TUBING

摘要

A method for producing a silica glass body having a low bubble content includes melting silica sand in a chamber (62) of a rotating furnace housing (20) to form molten silica. Helium-containing gas is fed into the chamber, both during introduction of the sand and during the heating step. The helium diffuses more readily from the molten silica than other gases, resulting in lower bubble content. After the melting stage the helium can be replaced by argon, resulting in an even lower bubble count. The furnace is heated by establishing a glas (60) between spaced electrodes (64, 66) within the chamber.