| 摘要 |
A process is disclosed for making a cylindrical glass preform by outside vapor deposition. Initially, a glass soot stream is directed from a deposition burner to a tapered mandrel, as the mandrel rotates about its longitudinal axis and as the burner reciprocates longitudinally along the mandrel. Mounted at opposite ends of the mandrel are a tubular glass handle and a glass tube having a closed end. After deposition has been completed, the mandrel is removed, leaving a porous glass preform with a central aperture and with the glass handle and the glass tube located at its opposite ends. The porous preform then is dehydrated and sintered into a dense glass preform, which is placed in an elongation machine that heats the end of the preform carrying the closed glass tube, while a vacuum is drawn from the central aperture via the handle. This collapses the aperture and elongates the preform into a solid glass rod. |
