Vacuum degassing apparatus, apparatus for producing glassware, and method for producing glassware

A vacuum degassing apparatus for molten glass, comprising:

• a vacuum housing, the interior of which is vacuumed;
• a vacuum vessel disposed in the vacuum housing for introducing molten glass thereinto;
• an introduction pipe and a discharge pipe disposed in the vacuum housing and assembled by a plurality of bricks, the introduction pipe and discharge pipe being respectively disposed upstream and downstream the vacuum vessel for introducing and discharging the molten glass, the introduction pipe and the discharge pipe being connected to the vacuum vessel;
• and
• an extension pipe connected to at least one of an upstream end of the introduction pipe and a downstream end of the discharge pipe and made of heat-resisting metal;
• the extension pipe including a base end portion formed on one end close to the vacuum vessel, a body portion formed so as to be continuous to the base end portion, and a sealing flange extending from an outer peripheral side of the body portion and mounted so as to cover through holes from an outer side of an outer wall for the vacuum housing, the sealing flange being positioned at at least one of the introduction pipe and the discharge pipe;
• and
• the extension pipe being detachably fixed to the outer side of the outer wall through a fixing structure disposed on an outer peripheral portion of the sealing flange at a position where the base end portion is received in an end brick constituting an opening on the upstream end of the introduction pipe or the downstream end of the discharge pipe.