| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a burner for manufacturing a porous glass preform, in a multinozzle burner in which combustible gas ejection ports and small diameter auxiliary gas ejection ports are adjacent without a seal gas, even in a region where the flow velocity of the small-diameter gas ejection ports is low, seizure is not generated at the tip of the small diameter gas ejection ports, and to provide a manufacturing method of a porous glass preform. Ž<P>SOLUTION: In the burner for manufacturing a porous glass preform, the outside of a glass raw material gas ejection port as the center is provided with a combustible gas ejection port, and one or more sequences of small diameter auxiliary gas ejection ports are provided inside the combustible gas ejection port, to be coaxial with respect to the glass raw material gas ejection port, and, in each of the sequences, the small diameter auxiliary gas ejection ports have the same focal length as each other, and have a concave portion at an end surface thereof. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
