Vacuum degassing apparatus for molten glass

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 to the vacuum degassing vessel, and sucks and draws up undegassed molten glass 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 at at least a part of the path for molten glass in the flow direction in said vacuum degassing vessel, a bottom portion at the center in the transverse direction of the path, has a ridge shape and bottom portions at both ends in the transverse direction of the path, which are located on both sides of the center bottom portion, have valley shapes.