SEAL STRUCTURE FOR OPTICAL FIBER DRAWING FURNACE

摘要

PROBLEM TO BE SOLVED: To provide a seal structure that can seal a gap created between an upper end opening or an optical fiber drawing furnace and an optical fiber preform by a simple structure even when the diameter variation of the optical fiber preform is large.

SOLUTION: The seal structure includes: a flexible seal member 21 arranged so as to abut on the side surface of the optical fiber preform 1; and a plurality of pressing mechanisms (members 22-28) for independently pressing the seal member 21 from each of equally divided directions in the multiple circumferential directions of the circumference of the optical fiber preform 1. The pressing mechanisms (members 22-28) convert gravity into horizontal force and obtain pressing force to the seal member 21.

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