| 摘要 |
PURPOSE:To improve the control of the feed of fine glass powder or quartz powder, and to eliminate the bubbles in the manufactured preform, in the manufacturing process of an optical fiber preform comprising the arbitrary heat- treatment and melting of fine glass powder or quartz powder, by exposing the powder to a specific atmosphere of vapor. CONSTITUTION:Fine glass powder and/or quartz powder 4 containing or devoid of a dopant such as GeO2 as a solid solution, are introduced into the treating vessel 1 through, e.g. a thick pipe 2. Separately, one or more materials selected from steam and alcohols are introduced as the gas for the elimination of electric charge into the vessel 1 through the pipe 7. In the case of steam, water is heated in the vessel 5 at a desired temperature, and the generated steam is transferred to the vessel 1 with the carrier Ar gas. After the elimination of the electric charge from the powder 4 by the exposure to the gas for the charge elimination, the powder is supplied through the pipe 3 into a flame or a plasma flame. The adhesion of the powder to the inner surface of the pipe or the cohesion of the powder caused by the electric charge can be prevented by this procedure. |
