| 摘要 |
PROBLEM TO BE SOLVED: To realize a clean environment inside the furnace, to prolong the service lives of furnace internals such as heating element and furnace heat insulator, and to improve furnace efficiency, in an optical fiber drawing furnace for drawing an optical fiber from a preform. SOLUTION: The optical fiber drawing furnace is provided with: a heating element 22 that is placed so as to encircle a preform and has an appropriate shape for heating; and a graphite liner 12 that has a shape corresponding to the shape of the heating element 22 and is used as a barrier between the heating element 22 and a preform. In this furnace, the graphite liner 12 is completely impregnated with glassy carbon throughout the graphite liner matrix so as to form a high density extruded liner, or the heating element 22 is completely impregnated with glassy carbon throughout the graphite heating element matrix so as to form a high density extruded graphite heating element, or further, both the graphite liner 12 and the heating element 22 are made of high density extruded graphite. |
