Patent ID: 6938442

Claim:
A process for producing a cylindrical component of quartz glass, said process comprising: drawing a cylinder from a softened quartz glass mass in a predetermined drawing direction along a drawing axis by a drawing apparatus engaging the cylinder; said drawing being at a drawing rate; the drawing apparatus comprising at least three guide elements arranged serially along the drawing axis and each being supported by a movable support for reciprocal movement in the drawing apparatus in the drawing direction and in an opposite direction, wherein the movable supports are such that each of said guide elements can be moved in said reciprocal movement independently of the other guide elements; said guide elements selectively frictionally engaging with the cylinder so as to guide the cylinder and disengaging from the cylinder so as to be able to move relative thereto; two of said guide elements simultaneously frictionally engaging the cylinder and maintaining a grip distance therebetween, and being moved at the drawing rate in the drawing direction while a third of said guide elements is disengaged from the cylinder and moved in the opposite direction; the guide elements each being associated with a respective working zone that corresponds to an individual segment along the drawing axis, the guide elements moving within their respective working zones in the drawing direction and in the opposite direction; wherein the guide elements move in the opposite direction at a reverse movement rate that is at least twice the drawing rate, the working zones being shorter than the grip distance by a distance, and the ratio of the distance to the length of the respective working zone being at least as great as the ratio of the drawing rate to the reverse movement rate.