| 摘要 |
PURPOSE:To prepare optical fiber having improved strength with preventing inner dusts from attaching to a preform rod and the optical fiber, by providing the cylindrical inner wall face of the main body of the furnace for spinning optical fiber with a gas jetting pipe having a jetting angle approximately coincident with the tangential direction of the cylindrical wall face. CONSTITUTION:The bottom end of the preform rod 9 is inserted at low speed from the inlet 2 of the main body 1 of a furnace to the interior 1 of the main body of a furnace in high-temperature state, the bottom end melted under heating is drawn at high speed to give the optical fiber 10, which is introduced from the outlet 3 to a coating process, etc., out of the main body 1. In the operation, the inlet 2 is sealed with the sealing medium 8, and a pure inert gas such as N2, Ar, etc. is jetted from the gas jetting pipes 6a, 6b and 6c to the main body 1. The direction of the jetting flow of the gas is coincident with the tangential direction of the inner face 5, so inner dusts produced in the main body 1 are moved to the side of the inner face 5 by centrifugal force, discharged from the opening 7 out of the furnace, and not attached to the rod 9 and the fiber 10. |
