| 摘要 |
PURPOSE:To effectively obtain the title high-quality optical fiber without unstable fiber stream with a low cost of the device by dropping a specified liq., and cooling the inside of a tubular cooling part by the vaporized gas or the heat of vaporization to cool the surface of the fiber. CONSTITUTION:A base material 1 is sent out into the furnace core tube 3 heated by a heating furnace 2, a specified tension is exerted on the tip of the base material 1 heated and melted in the furnace core tube 3 to draw the material in the axial direction, and a fiber 4 streams drawn out. The drawn fiber 4 is firstly passed through the tubular cooling part 13 and then introduced into a cooling die 5. The liq. 9 supplied into an upper liq. storage 17 from a tank 10 falls into a fiber cooling part 16 through a pore in the tubular cooling part 13, the liq. is vaporized during falling, and a cold gas is generated. In addition, the inside of the fiber cooling part 16 is cooled by the heat of vaporization. The drawn fiber 4 is passed through the inside of the fiber cooling part 16 and cooled. A liq. having the b.p. lower than room temp. is used as the liq. 9, such as liquefied N2 or Ar. |
