Patent ID: 7650764
Filing Date: 2010-01-26
Classification: C03B

Abstract:
1. A vacuum degassing apparatus for molten glass, comprising: a vacuum housing which is evacuated to be depressurized therein; a vacuum degassing vessel which is provided in the vacuum housing to vacuum-degas molten glass as the molten glass flows therein; an uprising pipe which connects upright to the vacuum degassing vessel and forms a path for molten glass extending between the lower end portion of the uprising pipe and the upper end portion of the uprising pipe, wherein undegassed molten glass is sucked and rises through said path in the uprising pipe to introduce the undegassed molten glass into the vacuum degassing vessel; and a downfalling pipe which connects to the vacuum degassing vessel and draws down degassed molten glass from the vacuum degassing vessel to discharge the degassed molten glass, wherein a lowermost position of a critical portion is located at the lower end portion or between the lower end portion and the upper end portion of the uprising pipe; wherein the cross sectional area of the path in said uprising pipe gradually increases from the lowermost position of the critical portion of the uprising pipe toward the upper end portion of said uprising pipe.