| 摘要 |
PURPOSE:In the process where glass fine particles are deposited on a cylindrical or tubular material on its outer surface, the material is always kept clean with a gas on its surface to produce the title deposit free from contaminants and bubbles. CONSTITUTION:Glass fine particles formed by burner 12 are deposited on the outer surface of a rod 11 which is being lifted, as it is rotated, and the undeposited particles are exhausted out of the tube 14 to form a deposit 13 of glass particles. At this time,the part of the rod for the glass particles to be deposited is covered with a muffle 18 for purging and a clean gas 17 for purging is fed from the inlet 19 to keep the surface of the part 16 always clean. Thus, in the following steps, the bubbling on the boundary surfaces can be avoided in the heat treatment in a high-temperature oven and contamination can also be inhibited. |
