Verfahren zur Herstellung eines Rohres aus glasigem Werkstoff, insbesondere aus Quarzglas

摘要

According to a prior method for producing a tube of glassy material, especially quartz glass, a hollow cylindrical tube rounds of glassy material is fed in an essentially vertical manner to a heating zone, where said tube rounds is heated and drawn off downwards to the tube without using tools and by producing a transition area from the tube rounds to the tube. The diameter and the wall thickness of the tube are continually measured and the measured geometrical data of the tube are used for generating a control signal by means of which a pressure difference between the pressure P1 in the inner chamber of the tube rounds, the transition area and the tube and the pressure P2 in the heating chamber is controlled in the heating zone at least in the transition area from the tube rounds to the tube and the tube area adjacent thereto. Said method should be refined in such a way that a broader spectrum of hollow cylindrical tube rounds can be processed to tubes having desired internal and external dimensions. The aim of the invention is to produce tubes whose ratio from the outer diameter (DRa) to the inner diameter (DRi) is greater than the ratio from the outer diameter (DHa) to the inner diameter (DHi) of the tube rounds. The pressure P1 in the inner chamber of the transition area and of the tube rounds and of the tube is maintained at a value which is less than the value of the pressure P2 in the heating chamber, whereby the pressure P1 is maintained by means of a suction pump.