Asahi Glass Company, Limited

Toshihiro Ishino

Yusuke Takei

Otojiro Kida

Michito Sasaki

Takashi Kijima

Toshiyasu Kawaguchi

Atsushi Tanigaki

Masataka Matsuwaki

Katsuharu Imamaki

Atsushi Hayashi

Yoshihisa Beppu

Nobuyuki Kido

Kouzou Sakai

Kohzo Sakai

Kiyoharu Kuwabara

Porous high-alumina fused cast refractory and method of its production

A vacuum degassing apparatus for molten glass according to the present invention comprises a vacuum housing where a vacuum is created; a vacuum degassing vessel housed in the vacuum housing to degas the molten glass; an introduction device communicated to the vacuum degassing vessel so as to introduce untreated molten glass into the vacuum degassing vessel, or preferably an uprising pipe; and a discharge device to discharge treated molten glass from the vacuum degassing vessel, or preferably a downfalling pipe. In the apparatus, at least a portion of at least one of the vacuum degassing vessel, the uprising pipe and the downfalling pipe that directly contact with the molten glass is constituted by refractory material having a porosity of not greater than 5%. The apparatus can increase quantity of flow of the molten glass and consequently a degassing throughput of the molten glass in comparison with prior art, having the same size and the same pressure loss. The apparatus can further increase the quantity of flow and the degassing throughput without making the size of the apparatus excessively larger.

Vacuum degassing apparatus for molten glass

A vacuum degassing apparatus for molten glass includes a vacuum housing where a vacuum is created; a vacuum degassing vessel housed in the vacuum housing to degas the molten glass; an introduction device communicated to the vacuum degassing vessel so as to introduce untreated molten glass into the vacuum degassing vessel, or preferably an uprising pipe; and a discharge device to discharge treated molten glass from the vacuum degassing vessel, or preferably a downfalling pipe. In the apparatus, at least a portion of at least one of the vacuum degassing vessel, the uprising pipe and the downfalling pipe that directly contact the molten glass is constituted by refractory material having a porosity of not greater than 5%. The apparatus can increase quantity of flow of the molten glass and consequently a degassing throughput of the molten glass, having the same size and the same pressure loss. The apparatus can further increase the quantity of flow and the degassing throughput without making the size of the apparatus excessively larger.

High zirconia fused cast refractories which include as chemical components of refractories in weight %, 85 through 91% of ZrO.sub.2, 7.0 through 11.2% of SiO.sub.2, 0.85 through 3.0% of Al.sub.2 O.sub.3, 0.05 through 1.0% of P.sub.2 O.sub.5, 0.05 through 1.0% of B.sub.2 O.sub.3 and 0.01 through 0.12% of a summed amount of K.sub.2 O and Na.sub.2 O, wherein the weight % of K.sub.2 O is not smaller than the weight % of Na.sub.2 O.

High zirconia fused cast refractories

A high zirconia fused cast refractory which comprises from 90 to 95% by weight of ZrO.sub.2, from 3.5 to 7% by weight of SiO.sub.2, from 1.2 to 3% by weight of Al.sub.2 O.sub.3 and from 0.1 to 0.35% by weight in a total amount of Na.sub.2 O and/or K.sub.2 O, and which does not substantially contain any one of P.sub.2 O.sub.5, B.sub.2 O.sub.3 and CuO.

High zirconia fused cast refractory

A high zirconia fused cast refractory having excellent thermal cycle resistance which comprises, as chemical components of the refractory, from 90 to 95% by weight of ZrO.sub.2, from 3.5 to 7% by weight of SiO.sub.2 and from 1 to 3% by weight of Al.sub.2 O.sub.3 and which does not substantially contain any one of P.sub.2 O.sub.5, B.sub.2 O.sub.3 and CuO.

A high zirconia fused refractory product consisting essentially of the following constituents analytically, on a weight basis:

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Yokohama, Japan

Toshihiro Ishino