METHOD FOR PRODUCING POROUS PREFORM AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a porous preform and an apparatus therefor by which centering of a starting preform rod and surface treatment throughout the whole area of the starting preform rod can be carried out in the apparatus for producing the porous preform and generation of a foam caused from the starting preform rod or a burner for flame processing can be suppressed to allow a high-speed deposition. SOLUTION: This method is characterized by comprising setting the burner 12 for flame processing in a transfer mechanism separately installed from a transfer mechanism of a burner 4 for generating a glass particulate, smoothly carrying out flame processing of the surface of the starting preform rod 1 by the burner 12 for flame processing and then depositing the glass particulate on the starting preform rod 1 by the burner 4 for generating the glass particulate when transferring the burner 4 for generating the glass particulate along the starting preform rod 1 and depositing the glass particulate generated by a flame hydrolysis reaction on the starting preform rod 1 to form a glass particulate deposition.