Patent ID: 9567252
Date: 2017-02-14
CPC Classifications: C03B

Claim:
1. An optical fiber drawing method for drawing an optical fiber by joining an optical fiber glass preform to a dummy rod and hanging and downwardly moving the optical fiber glass preform inside a drawing furnace while sealing with a seal mechanism of an upper part of the drawing furnace, comprising: starting drawing of the optical fiber; sealing an outer peripheral surface of the optical fiber glass preform with a first seal part of the seal mechanism; and starting a vicinity of a taper part of the optical fiber glass preform to pass through the first seal part, performing switching to a second seal part arranged above the first seal part, and sealing an outer peripheral surface of a sleeve member fixed so as to surround an outer periphery of the dummy rod with the second seal part and downwardly moving the sleeve member together with the optical fiber glass preform until the drawing is ended.