METHOD FOR THE PRODUCTION OF A HOLLOW CYLINDER MADE OF SYNTHETIC QUARTZ GLASS WITH THE AID OF A HOLDING DEVICE, AND APPROPRIATE HOLDING DEVICE FOR CARRYING OUT SAID METHOD

摘要

In a previously known method for producing a hollow cylinder made of synthetic quartz glass, a silicon-containing compound is flame-hydrolyzed and SiO2 particles are deposited layer by layer on a rotating support, resulting in the production of an elongate porous soot body (5) having a central internal bore. Said soot body is dehydrated, doped, or vitrified, a process during which the soot body is held in a vertical direction inside a treatment oven by means of a holding device (9) comprising an elongate holding body (1) which protrudes into the internal bore of the soot body and is made of a material having a higher softening temperature than quartz glass. The aim of the invention is to create a method which is based on the previously known method and by means of which the purity of the hollow cylinder is maintained during said heating process while requiring little time and material for aftertreating the internal bore. Said aim is achieved by providing a gas-impermeable envelope (2) made of synthetic quartz glass between the holding body and the soot body. The holding device that is appropriate for carrying out the inventive method is characterized by the fact that a gas-impermeable envelope made of synthetic quartz glass is provided between the holding body and the soot body.