| 摘要 |
PROBLEM TO BE SOLVED: To provide a drawing oven having an oven core pipe through which a preformed material for optical fiber is fed, a heater surrounding the core pipe, and electrode joints, designed to obtain high-quality optical fibers reduced in nonroundness and low in connection loss by providing a means to uniformize the temperature distribution along the circumferential direction of the heater. SOLUTION: An example of a uniformizing means is shown in the figure. A heater 18 has an exothermic part 21 meandering vertically and cylindrical as a whole, a pair of supports 34, 35 rising on the upper end of the exothermic part 21 so as to stand against and 180 deg. apart from each other along the circumferential direction of the exothermic part, and electrode joints 22-25 projected respectively outside the radial direction from both ends of a part forkedly branched from the upper ends of these supports along the circumferential direction of the exothermic part 21, and the whole of these are made of graphite. Besides, at an intermediate part between the supports 34 and 35, an extended part 36 is provided so as to set its vertical height higher than the other parts to ensure heat balance between the extended part 36 and the supports 34, 35. |
