| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drawing apparatus and a drawing method for optical fiber where soot does not accumulate to the inner diameter direction, even if gas in a gap furnace case neighboring the joint of a furnace core tube lower end is flowed into the furnace core tube. <P>SOLUTION: The gap width H of the outlet part at the gas leakage outlet of the joint is set for satisfying [R=(3D<SP POS="POST">2</SP>Q<SB POS="POST">2</SB>)/(4H<SP POS="POST">2</SP>Q<SB POS="POST">1</SB>)≤3], wherein the volume flow rate of inert gas which is flowed into the furnace core tube 13 and flows downward is taken as Q<SB POS="POST">1</SB>, the volume flow rate of inert gas which leaks from the furnace housing 14 into the furnace core tube is taken as Q<SB POS="POST">2</SB>, the inner diameter of the furnace core tube lower end is taken as 2D, the gap width for the outlet at gas leakage outlet 19 of the joint of the furnace core tube 13 and the extension tube 17 is taken as H, and the ratio of shear force of Q<SB POS="POST">1</SB>and Q<SB POS="POST">2</SB>at the wall surface where the volume flow rate Q<SB POS="POST">1</SB>and Q<SB POS="POST">2</SB>intersect is taken as R. <P>COPYRIGHT: (C)2013,JPO&INPIT |
