| 摘要 |
PROBLEM TO BE SOLVED: To reduce the decentering and outer diameter fluctuation width of a glass rod to obtain a good optical fiber, by disposing mechanisms for inhibiting the rise in the temperatures of portions for gripping a glass rod. SOLUTION: In this processing device, cooling devices 5 are disposed in portions 4 for gripping a quartz-based glass rod 7 whose inner portion is hollow. Cooling water is circulated in the cooling devices 5 to protect the gripping portions 4 from the radiant heat of a burner 1. In the device, a mixed gas of oxygen with hydrogen is supplied to a burner 1, and, for example, a burner and a glass rod which has an outer diameter of 50 mm and a length of 1,000 mm and is rotated at 15 rpm are relatively moved at a rate of about 20 mm/min to carry out a flame polishing treatment. Therein, the grip portions 4 are held at an extremely low temperature of about 45 deg.C. Consequently, the change in a driving force for rotating the glass rod 7 due to the deformation of the grip portions 4 is not caused, and the processed glass rod 7 having an outer diameter value in an extremely high processing accuracy fluctuation width of 0.02% is obtained. |
