INDUCTION FURNACE USED FOR STRETCHING LARGE DIAMETER PREFORMED BARS OF OPTICAL FIBER

摘要

An induction furnace used for stretching large-diameter preformed bars of optical fiber, said furnace comprising a furnace casing, a graphite exothermic sleeve, an insulating layer and an induction coil. At the upper end of the graphite exothermic sleeve is provided a floating seal gland, the inner bore thereof being adapted to the upper end of the graphite exothermic sleeve, and the outer periphery of the floating seal gland being adapted to the top cover plate furnace hole of the furnace casing. The use of the floating seal gland increases furnace stability and prolongs furnace life.