FURNACE AND PROCESS FOR OPTICAL FIBER DRAWING

摘要

A drawing furnace for an optical fiber comprises a member in which a preform for the optical fiber is accommodated, a muffle tube connected to the accommodating member, around which a heater is disposed and in which a tip portion of the preform is heated and melted. Inert purging gas is supplied to the muffle tube or to both the accommodating member and the muffle tube. The invention is characterized in that at least a portion of at least one of the muffle tube and the accommodating member comprises at least two furnace walls defining a space between them. The outermost wall has an inlet through which the purging gas is supplied to the space, and the innermost wall has an outlet through which the purging gas leaves the space after flowing between the walls.