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

摘要

Provided are a seal structure for an optical fiber drawing furnace and an optical fiber drawing method that are capable of avoiding external air being drawn into a drawing furnace, capable of reducing the amount of inert gas used, and capable of reducing variation in the diameter of the drawn optical fiber. The seal structure for the optical fiber drawing furnace is for sealing gaps between an upper end opening in the optical fiber drawing furnace and the optical fiber glass base material inserted from the upper end opening. The seal structure comprises: a plurality of blade members; a supporting mechanism that supports the plurality of blade members; and a press-action mechanism that presses each of the plurality of blade members in the radial direction of the optical fiber glass base material, such that the tips of the plurality of blade members come in contact with the side surface of the optical fiber glass base material. The pressing force when the plurality of blade members come in contact with the optical fiber glass base material is 0.1-10 N per blade member.