| 摘要 |
PURPOSE:To obtain an optical transmission glass fiber base material of large diameter and long size with high productivity by heating a glass tube composite body, to a high temp., grown by feeding gas of a glass-forming metal cpd. and steam from a glass tube end which is not a growing portion. CONSTITUTION:Gas of silicon halide or hydride, steam, hydrogen gas, inert gas and oxygen gas are fed to burner nozzle 1 to form combustion flame 2, and silicon dioxide powder 3 formed is supplied onto quartz glass tube substrate 10 to continuously form transparent quartz glass tube 7 while melting with oxyhydrogen flame 4. When the form of a tube 7 growing portion becomes stable, while feeding gas of silicate glass-forming metal cpd. 5 and steam together with carrier gas 6 to the growing portion from an end which is not a tube 7 growing portion, composite body 12 provided with molten body 9 and sintered body 8 on the inner wall of tube 7 is grown. Body 12 grown to a predetermined length is then heated with oxyhydrogen burner 15 to vitrify body 8 and made solid. |
