SINTERING FURNACE FOR PRODUCING QUARTZ BASE MATERIAL.

摘要

A furnace used for conducting at least one of the steps of dehydration, fluorine addition and sintering of porous quartz base material prepd by flame hydolysis techniques such as vaporphase axial deposition or outside seeding, which makes it possible to keep completely airtight the joints of a long core tube, which cannot be mfd. monolithically, to prevent moisture, oxygen and other impurities contained in the outer atmosphere from intruding inside the core tube, and to prevent corrosive and toxic gases present inside the core tube from leaking outside. The core tube is made of high-purity carbon with its inner wall and/or outer wall being coated with a gas-impermeable coating film. It has a cylindrical form with its axis extending lengthwise, and is divided into several portions along the axis, and the upper and lower edges of each divided portions are flattened to provide contact faces, which are sealed with carbon packing interposed therebetween. The core tube has a mechanism for axially pushing it with a uniform force from around its periphery.