Patent ID: 9242887
Filing Date: 2016-01-26
CPC Classification: C03B

Claim Text:
1. A method for drawing a quartz-glass strand, said method comprising: feeding a crucible with SiO softening said granules therein to obtain a quartz glass mass, drawing off the softened quartz-glass mass vertically downwards as a quartz-glass strand via a drawing nozzle, said nozzle being provided in a bottom area of the crucible and having a drawing nozzle opening, detecting a wall thickness profile of the quartz glass strand, heating the drawing nozzle using a plurality of heating elements which are distributed around the drawing nozzle opening and are electrically controllable independently of one another, and heating the quartz glass mass locally with the heating elements within the drawing nozzle opening in response to measurement results of the wall thickness profile; and wherein a position and an amount of a wall thickness deviation of the quartz glass strand are determined, the determined position being used to determine which of the heating elements is activated and the determined amount being used to regulate a heating temperature thereof.