| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing a porous glass perform, in which characteristics of the porous glass perform are stable in the longitudinal direction and bubbles are hardly mingled when the porous glass perform for an optical fiber is synthesized by the VAD method. <P>SOLUTION: A reaction gas 15 containing a glass raw material gas and a combustion gas is jetted out from one or more burners 13 installed in a reaction vessel 11, and glass microparticles formed by the reaction of the reaction gas 15 are deposited on a target 17 to fabricate a porous glass perform 19. A clean air jet-out port 27 is disposed on a wall surface 21a of the reaction vessel 11 for the porous glass preform 19 such that the lower end 25 of the jet-out port is installed at a lower position than a lower end 23 of a burner 13 whose raw material charge amount is most. The clean air jet-out port 27 is set upward toward an exhaust port 29 positioned on a wall surface 21b opposing to the burner 13 and opening upward, and clean air 31 is fed from the clean air jet-out port 27 to the reaction vessel 11. <P>COPYRIGHT: (C)2012,JPO&INPIT |
