| 摘要 |
PURPOSE:To prevent occurrence of flawing in a drying step, etc., and obtain a glass body in good yield, by preparing a wet gel, providing a protective film on the surface with the wet gel, carrying out drying and sintering and removing the protective film in the course of sintering. CONSTITUTION:Ethyl silicate is blended with water, hydrochloric acid, fine powdery silica, etc., to carry out hydrolysis and produce a sol solution. Aqueous ammonia is then added to the sol solution and the resultant solution is put in a cylindrical rotating vessel and gelatinized while rotated to produce a tubular wet gel. Aqueous ammonia is added to a separate sol solution and the resultant solution is used to prepare a protective film on the surface of the tubular wet gel. The resultant protective film is then dried to give a dry gel, which is then sintered and taken out in the course of sintering to peel the protective film with tweezers, etc. Sintering is then completed to afford the aimed glass tube without flows on the inner surface thereof. |
