| 摘要 |
PURPOSE:To uniform outer diameter of parent material of preform of optical fiber by arranging plural burners of the same dimension at equal intervals at the outer periphery of core glass rod for optical fiber and making the shape of piled material uniform according to piling schedule by control. CONSTITUTION:Three or more oxyhydrogen flame burners 2 of the same dimension are arranged in series at the outer periphery of a glass rod 1 for optical fiber. Then a gaseous glass raw material is sent to the burners 2, hydrolyzed by flame, generated fine particles are piled on the glass rod 1 to form a porous glass preform 4. The outer diameters of the preform 4 along the whole length are measured by an outer diameter by a measuring device 6 of outer diameter, the average outer diameter is obtained, simultaneously the whole weight is measured, difference between given preset outer diameter and the weight is detected, a gas condition of each burner 2 is always compensated and controlled by using a control mechanism A attached to a gas main valve 5 and control mechanisms B fixed to each burner 2 based on the difference. |
