| 摘要 |
PURPOSE:To obtain a dehydrating and sintering furnace for producing the base material of optical fiber which is capable of dehydration of the base material, addition of an element for controlling refractive index and treatment velocity of sintering by forming an annular heater surrounding a furnace core pipe penetrating a hollow furnace body so that calorific value in the central part of the vertical direction is made smaller than the calorific value in the upper and lower end parts. CONSTITUTION:In the titled sintering furnace consisting of both a furnace core pipe 2 penetrating the inside of a hollow furnace body 1 and an annular heater 3 surrounding the furnace core pipe 2, the heater 3 (30) is constituted as follows. In other words, respective slits 30a provided to the heater 30 are made narrow by linearly decreasing the width to the center 0 of an interval A from one end edge part and thereafter these are formed at the same width until the vicinity of the other end edge. As a result, calorific value in the central part can be made smaller than the calorific value in the upper and lower end parts. In the titled dehydrating and sintering furnace of this invention, uniformity of temp. distribution in the heating zone is enhanced and dehydration of a base material for optical fiber, addition of an element for controlling refractive index and shortening of treatment time for sintering are enabled and also the quality of the produced optical fiber can be enhanced. Further an electrode is shown as 7 in the figure. |
