Production of a cylindrical glass body, especially a quartz glass body, in a vertical drawing process comprises feeding a glass blank to a heating zone, softening the blank, and withdrawing a glass strand from the softened region

摘要

Production of a cylindrical glass body, especially a quartz glass body, in a vertical drawing process comprises feeding a glass blank to a heating zone; softening the blank; and withdrawing a glass strand (5) from the softened region at a controlled speed using an extractor. The drawing speed is controlled via the number of revolutions of a reference rolling body (3) of the extractor. A value for the torque of the reference rolling body is determined depending on the weight of the glass strand withdrawn. The determined value is taken as the theoretical torque for adjusting the torque of the auxiliary rolling body (4, 7, 8) of the extractor. An independent claim is also included for a device for the production of a cylindrical glass body. Preferred Features: An extractor is used which has a withdrawal unit having several rolling bodies which move in a direction vertical to the longitudinal axis of the glass strand.