| 摘要 |
PURPOSE:To improve the yield in the initial stage and shorten the time of the initial stage, by changing the relative position of a combustion burner to the base material gradually in the initial stage in producing the titled base material using a flame hydrolytic reaction. CONSTITUTION:For example, in producing a porous glass base material with one burner 12, the initial position of the burner 12 is set at the position shown in the figure. Thus, the burner 12 is set at the position where the central axis 14 passes the pulling up controlling position 13 of the above-mentioned base material (the base material is pulled up to place the tip of the base material always at this position). The burner 12 is moved at about 1mm for 5min in the direction of arrow 15 as fine particles of glass apply to the stating material or core rod 11 and finally moved at about 6mm distance. Thus, the tip shape of the base material is stabilized, and the time to reach the steady state can be shortened. |
