METHOD FOR MANUFACTURING GLASS PREFORM

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass preform by which the temperature rising of a plastic-containing duct is prevented in discharging an exhaust gas from a reaction vessel in which the glass preform is manufactured. SOLUTION: In the method for manufacturing the glass preform, when the exhaust gas is discharged from the reaction vessel 10 for manufacturing a porous glass preform G using flame through a metallic duct 20 and a plastic-containing duct 21 present in the downstream side of the metallic duct 20, the temperature of the exhaust gas is measured and air (a gas for cooling) is introduced and the introducing quantity is controlled so that the temperature of the exhaust gas introduced into the plastic-containing duct 21 does not exceed the allowable temperature of the plastic-containing duct 21. COPYRIGHT: (C)2005,JPO&NCIPI