| 摘要 |
A porous glass base material manufacturing burner comprising a combustible gas emission nozzle having one or more rows of small-diameter combustion assisting gas emission nozzles arranged around a central glass raw material gas emission nozzle. When a cross section of the burner formed by cleaving in a direction perpendicular to a central axis of the burner is divided into four equal regions by two orthogonal straight lines intersecting at a center of the cross section, total flow path surface area of the small-diameter combustion assisting gas emission nozzles included in two of the four regions through which passes a straight line running along the starting member and through the center of the cross section is less than the total flow path surface area of the small-diameter combustion assisting gas emission nozzles included in the other two of the four regions. |
