PRODUCTION OF FLUORINE-DOPED HIGH-PURITY QUARTZ GLASS PIPE

摘要

PURPOSE:To produce the titled quartz pipe having smooth and high-accuracy inner and outer surfaces without causing cracking in the pipe, by depositing pure silica glass soot by VAD process, preliminarily sintering the deposited soot to form a porous intermediate, boring the intermediate and melting and integrating the bored intermediate. CONSTITUTION:Deposited pure silica glass soot is preliminarily sintered to obtain a porous intermediate, which is bored and integrated by melting in a furnace. The preliminary sintering or melt integration is carried out in an atmosphere (e.g. He) added at least temporarily with fluorine. It is preferable to grind the outer surface of the above porous intermediate before or after the boring process to improve the dimensional accuracy of the produced glass pipe.