APPARATUS FOR PRODUCING PREFORM FOR OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To obtain an apparatus for producing a preform for optical fibers constituted to maintain the specified deposition rate in the axial and diametral directions of soot by suppressing the change in the flow direction of the waste gas by clogging of the inlet part of a discharge pipe in formation of the porous preform by a VAD method. SOLUTION: A quartz target rod 10 and a burner 11 are housed into a reaction vessel 9. The target rod 10 is so constituted as to be pulled up according to the deposition of oxide soot. The discharge pipe 13 is connected to the side part of the reaction vessel 9. The reaction vessel 9 near the connecting port of the discharge pipe is internally provided with a discharge direction regulator 16 constructed by assembling and connecting plural sectorial valve members 16a around a central connecting part 16b and a discharge direction detector 15. The opening and closing of the respective valve members 16a are controlled by the signals from the discharge direction detector 15 and the flow direction of the waste gas from the reaction vessel 9 to the discharge pipe 13 is so controlled as to be kept constant and optimum.