DEHYDRATION SINTERING FURNACE FOR OPTICAL FIBER PREFORM

摘要

PURPOSE:To provide the dehydration sintering furnace for an optical fiber preform capable of absorbing the short and periodic pressure fluctuations in a furnace core tube. CONSTITUTION:The optical fiber preform 1 to be dehydration sintered is housed into the furnace core tube 2. A heater 3 for heating the optical fiber preform 1 is placed outside the furnace core tube 2. A furnace body 5 housing a heater 3 via a heat insulating material 4 is placed on the outer periphery of the furnace core tube 2. An inert gas is supplied into the furnace core tube 2 and into the furnace body 5. The gaseous pressures in the furnace core tube 2 and the furnace body 5 are compared by a differential pressure gage 11 and these pressures are so controlled by a motor operated valve 12 in such a manner that the gaseous pressure in the furnace core tube 2 attains the prescribed pressure. A pressure fluctuation absorbing container 13 for absorbing the fluctuation in its internal pressure is connected to the furnace core tube 2.