SEAL STRUCTURE OF FIBER DRAWING FURNACE FOR OPTICAL FIBER AND FIBER DRAWING METHOD FOR OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a seal structure of a fiber drawing furnace for an optical fiber and a fiber drawing method for the optical fiber which can achieve avoidance of entrainment of outside air into a fiber drawing furnace and reduction in an amount of use of an inert gas and the like.SOLUTION: The seal structure of a fiber drawing furnace for an optical fiber is provided which closes a gap between an upper-end opening part of the fiber drawing furnace for the optical fiber and an optical fiber glass preform to be inserted from the upper end opening part. A plurality of blade members 14, 15 are arranged alternately in two upper and lower stages, and have tip parts 14a, 15a which abut on a side face of the optical fiber glass preform 5. The tip parts are formed in such a shape that the tip parts come into linear contact with the side face of the optical fiber glass preform, in a position where the upper and lower blade members overlap each other.