| 摘要 |
PROBLEM TO BE SOLVED: To prevent oxidation or burning out of a heater and a heat insulator made of a carbon material and to extend their life in a heating furnace for manufacturing an optical fiber, having a heating part equipped with the heater and the heat insulator. SOLUTION: In the heating furnace equipped with the heating part 2 comprising the heater 4 and the heat insulator 5 made of the carbon material, the heating part 2 is provided with an inert gas inlet 9. The inert gas inlet 9 is connected to an inert gas cylinder 10 as an inert gas supply source and inert gas such as argon is introduced into the heating part 2 to control the inner pressure of the heating part 2 higher than the external pressure by≥2 Pa so as to prevent intrusion of external air into the heating part 2. COPYRIGHT: (C)2004,JPO |
