| 摘要 |
PURPOSE:To improve strength and quality by feeding the atmosphere gases past the circumference of a heater in a furnace body to the inside of a furnace core tube from its outlet side. CONSTITUTION:The atmosphere gases consisting of inert gases, such as He and Ar, are steadily supplied from gas introducing ports 27, 28 installed in the inlet part 23 and outlet part 24 of the furnace body 21 and the excess atmosphere gases are discharged to the exterior of the furnace body 21. While a glass rod G inserted from the inlet part 23 of the furnace body 21 into the furnace core tube 29 is heated by the heater 35, the glass rod is stretched by a take off device from the outlet part 24 side of the furnace body 21 to form an optical fiber F. Since the stretched outside diameter is determined by the relative relation between the introducing speed and stretching speed of the glass rod G, the optical fiber F of the desired outside diameter is obtd. by adjusting a speed difference. |
