| 摘要 |
PROBLEM TO BE SOLVED: To provide a sealing member for a gap between the inner surface of a hole of the sealing member and an optical fiber preform. SOLUTION: A part of an inert gas fed from a communicating port 24 to grooves 30 is made to flow spirally along a first groove 31 and a second groove 36. Thereby, the gap 22 can be sealed across the whole peripheral direction of the hole 21. A part of the inert gas fed from the communicating port 24 to the grooves 30 is made to flow upward along the first groove 31. Then, the gas is discharged upward from the upper end of the gap 22 (flow 22f). Thereby, the inflow of the air from the gap 22 inside a fiber drawing furnace body can be suppressed. Therefore, the gap 22 can be sealed better as compared with the case of no grooves 30. A part of the inert gas fed from the communicating port 24 from the grooves 30 is made to flow downward along the second groove 36. Then, the gas is discharged downward from the lower end of the gap 22 (flow 22g). Therefore, the inert gas can be fed better inside the optical fiber drawing furnace body, as compared with the case of no grooves 30. COPYRIGHT: (C)2011,JPO&INPIT
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