TRANSPARENT VITRIFICATION FURNACE FOR OPTICAL GLASS SOOT

摘要

PURPOSE:To prevent an inside wall of a quartz reactor core pipe from being eroded by fluorine in case of inserting optical glass soot into the inside of the quartz reactor core pipe in the fluorine-contg. atmosphere and subjecting it to transparent vitrification by providing a formation part of a gas curtain due to inert gas to the inside wall of the reactor core pipe. CONSTITUTION:A blow-off port 4 of a shielding gas is provided to a bottom part of a part 1b to be shielded of an inside wall of a quartz series reactor core pipe 1. Inert gas (e.g., Ar) is introduced through an introduction port 5 of the shielding gas and blown off to the inside of the reactor core pipe 1 through the blow-off port 4 and discharged via a blow-in port 6 and an exhaust port 7. Thereby a gas curtain due to inert gas is formed in the part 1b to be shielded and the part 1b is shielded. Simultaneously a fluoride-contg. gas (e.g. gaseous mixture of SF6 and He) is introduced into the inside of the reactor core pipe 1 through an introduction port 2 and the inside of the reactor core pipe 1 is made to the fluoride-contg. atmosphere, and optical glass soot 10 is introduced into the inside of the reactor core pipe 1 and heated by an electric furnace 8 to subject it to transparent vitrification.