| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber drawing furnace in which the degradation of a furnace core pipe by oxidation and the deterioration of strength of an optical fiber are prevented by preventing the flow-in of atmospheric air in a furnace core. SOLUTION: In the optical fiber drawing furnace 21 for drawing an optical fiber preform 23 to which a dummy rod 22 is connected in advance, a sheet like heat resistant sealing material 28 for preventing the flow-in of the atmospheric air to the inside of the furnace core 26 by sealing a gap between the optical fiber preform and an optical fiber preform inserting port 27 on the upper part of the furnace core pipe 25 of the drawing furnace 21 is provided in the optical fiber preform inserting port 27, a small chamber 29 covering the sheet like heat resistant sealing material 28 is formed above the optical fiber preform inserting port 27 and a sheet like sealing material 43 for sealing a gap formed between the dummy rod 22 and the optical fiber preform inserting port 35 in the upper part of the small chamber 29 is provided in the dummy rod 22 side of the outside of the small chamber 29. COPYRIGHT: (C)2003,JPO |
