Patent ID: 9352994
Filing Date: 2016-05-31
CPC Classification: C03B

Claim Text:
1. A method, comprising: passing a molten silicate glass through a glass flow passage in a vacuum degassing vessel, the interior of which is maintained in a reduced pressure state, to vacuum-degas the molten glass, the molten silicate glass comprising a refining agent containing S (sulfur) element, an amount of the refining agent in the molten silicate glass being 0.043 weight % or more as calculated as SO wherein vacuum-degassing of the molten glass is carried out under conditions satisfying formula (1) at least at a bottom portion on a downstream side of the glass flow passage of the vacuum degassing vessel, such that formation of bubbles at an interface between furnace material of the vacuum degassing vessel and the molten silicate glass is suppressed: wherein: