MULTITUBE BURNER AND PRODUCTION OF GLASS PREFORM FOR OPTICAL FIBER USING THE SAME

摘要

PROBLEM TO BE SOLVED: To form stable flame without causing condensation of the source material of a glass preform by controlling the flame in such a manner that the temp. of the flame where the source material of the glass preform for an optical fiber is passed as vaporized by the heat of the oxyhydrogen flame is kept higher than the boiling temp. of the source material of the glass preform. SOLUTION: This multitube burner consists of cylindrical quartz glass tubular burners A1 to A4 each having <=1.5 mm thickness arranged from the inside in this order and has gas passages B1 to B4 arranged in this order for the source materials of oxyhydrogen flame and for a glass preform for an optical fiber. The gas passage B1 is used as a passage for the source material of the glass preform, the passage B2 is used as a passage for an inert gas such argon, the passage B3 is used as a passage for hydrogen to produce oxyhydrogen flame, and the passage B4 is used as a passage for oxygen to produce oxygen flame. The source materials of oxyhydrogen flame are combusted by the multitubular burner and the part of the flame where the source material of the glass preform passes as heated by the flame is kept higher than the boiling temp. of the source material of the preform. Then the source material of the glass preform is supplied and hydrolyzed in the flame to produce the glass preform.