Patent ID: 8245542
Filing Date: 2012-08-21
Classification: C03B

Abstract:
1. A method for producing a cylinder of synthetic quartz glass, said method comprising the following method steps: (a) forming SiO (b) thermally drying the porous soot body by holding said porous soot body within a range of a drying temperature in such a way that a predetermined mean concentration of hydroxyl groups and a radial profile of the hydroxyl group concentration with a maximum in the inner portion of the soot body are obtained; and (c) vitrifying the dried soot body so as to form the cylinder of synthetic quartz glass, wherein the dried SiO (I) heating the soot body to a consolidation temperature to form a sealing layer in an area of the at least one cylinder jacket surface, the sealing layer sealing the inner portion to the outside; (II) cooling the soot body from the consolidation temperature; and (III) annealing the soot body by heating it in a range of a homogenization temperature during a period of at least 5 h so that the radial profile of the hydroxyl group concentration flattens in the inner portion.