METHOD AND APPARATUS FOR PRODUCING POROUS GLASS PREFORM

摘要

PROBLEM TO BE SOLVED: To produce a high quality porous glass preform by controlling the adhesion of fine glass particles on an upper inner tube inside and by preventing the bad condition of the porous glass preform caused by the fine glass particles heaped on the upper inner tube inside. SOLUTION: An apparatus for producing the porous glass preform is that an upper tube 2 which has a double-tube structure consisting of an inner wall 5 and an outer wall 6 is set on a reaction vessel 1 where a burner 11 to generate the fine glass particles is set and that a plurality of blow outlets 8 to blow a gas supplied to a flow path 7 which is a space between the inner wall 5 and the outer wall 6 are formed on the inner wall 5 at the lower half of the upper tube 2. A method for producing the porous glass preform is that the adhesion of surplus glass particles on the inside of the upper tube 2 is controlled by blowing the gas, which is an inert gas supplied to the flow path 7 when the glass particles are heaped on a starting rod 3 in the reaction vessel 1, from the blow outlets 8 into the upper tube 2. COPYRIGHT: (C)2005,JPO&NCIPI