Vacuum degassing apparatus for molten glass

A parallel arrangement of vacuum degassing apparatus comprising;

• a plurality of vacuum degassing units for vacuum-degassing molten glass supplied from a melting vessel;
• and
• a merging unit for merging the molten glass supplied from the vacuum degassing units, stirring the merged molten glass and supplying the stirred molten glass to a downstream side;
• wherein each of the vacuum degassing units includes a vacuum housing where a vacuum is created, a vacuum degassing vessel housed in the vacuum housing to vacuum-degas the molten glass, an introduction device communicated to the vacuum degassing vessel so as to introduce the molten glass before degassing into the vacuum degassing vessel;
• and a discharge device communicated to the vacuum degassing vessel so as to discharge the molten glass after degassing from the vacuum degassing vessel into the merging unit;
• wherein a pressure-equalizing pipe is provided to communicate between the vacuum degassing units;
• and
• wherein the pressure-equalizing pipe is provided with a cock to close communication between the vacuum degassing vessels.

A vacuum degassing apparatus for molten glass comprising:

• a plurality of vacuum degassing units for vacuum-degassing molten glass supplied from a melting vessel;
• and
• a merging unit for merging the molten glass supplied from the vacuum degassing units, stirring the merged molten glass and supplying the stirred molten glass to a downstream side;
• wherein each of the vacuum degassing units includes a vacuum housing where a vacuum is created, a vacuum degassing vessel housed in the vacuum housing to vacuum-degas the molten glass, an introduction device communicated to the vacuum degassing vessel so as to introduce the molten glass before degassing into the vacuum degassing vessel, and a discharge device communicated to the vacuum degassing vessel so as to discharge the molten glass after degassing from the vacuum degassing vessel into the merging unit;
• wherein a pressure-equalizing pipe is provided to communicate between the vacuum degassing units;
• wherein at least portions of the introduction device, the vacuum degassing vessel and the discharge device that directly contact the molten glass are constituted by refractory material having a porosity of not greater than 5%;
• and
• wherein a cortex of the refractory material is scalped by at least 5 mm.

A vacuum degassing apparatus for molten glass, comprising:

• a vacuum housing where a vacuum is created;
• a vacuum degassing vessel housed in the vacuum housing;
• an introduction device communicated to the vacuum degassing vessel so as to introduce molten glass before degassing into the vacuum degassing vessel;
• and
• a discharge device communicated to the vacuum degassing vessel so as to discharge the molten glass after degassing from the vacuum degassing vessel;
• wherein the vacuum degassing vessel includes a path to flow a large quantity of the molten glass and a degassing space, and a portion of the path that directly contacts the molten glass is constituted by refractory material having a porosity of not greater than 5%;
• and
• further wherein a cortex of the refractory material that directly contacts the molten glass is scalped by at least 5 mm.