Abstract: A vacuum degassing apparatus for molten glass includes 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 the degassed molten glass from the vacuum degassing vessel to discharge the degassed molten glass. The cross sectional area of the path at the upper end portion of the uprising pipe is larger than the cross sectional area of the path at the lower end portion of the uprising pipe.

Abstract: A vacuum degassing apparatus for molten glass includes 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 the degassed molten glass from the vacuum degassing vessel to discharge the degassed molten glass. The cross sectional area of the path at the upper end portion of the uprising pipe is larger than the cross sectional area of the path at the lower end portion of the uprising pipe.

Abstract: A method for reducing NOx, in a combustion gas which is discharged from a combustion furnace for burning a fuel by means of a gas containing oxygen in an amount of at least 80 vol % and which contains oxygen, which method comprises adding a combustible material to the combustion gas at a temperature of from 1,000 to 1,500° C., wherein the combustible material contains a compound comprising C and H.

Abstract: 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 the degassed molten glass from the vacuum degassing vessel to discharge the degassed molten glass; wherein the cross sectional area of the path at the upper end portion of said uprising pipe is larger than the cross sectional area of the path at the lower end portion of said uprising pipe.

Abstract: A method for reducing NOx, in a combustion gas which is discharged from a combustion furnace for burning a fuel by means of a gas containing oxygen in an amount of at least 80 vol % and which contains oxygen, which method comprises adding a combustible material to the combustion gas at a temperature of from 1,000 to 1,500° C., wherein the combustible material contains a compound comprising C and H.

Abstract: Molten glass has a liquid level located at a higher level than lower ends of an uprising pipe and a downfalling. In addition, a contacting portion of the uprising pipe or the downfalling pipe and a brick receiver on an upstream or downstream pit for supporting the uprising or downfalling pipe, or a joint in the brick receiver is filled with sealing material.

Abstract: A vacuum degassing apparatus for molten glass, comprising:

Abstract: 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.

Abstract: A vacuum degassing apparatus comprises a path made of dense refractory bricks, the path including an inner surface brick layer, the refractory bricks in the inner surface brick layer having a flatness of 0.5 mm on contacting surfaces with one anther, and the path including a backup brick layer and a ramming material filling layer besides the inner surface brick layer.

Abstract: A vacuum degassing method for molten glass, which comprises introducing molten glass into a vacuum degassing apparatus, subjecting it to degassing treatment under a predetermined reduced pressure condition and then withdrawing it for a subsequent step, wherein during the degassing treatment, a metal compound which is at least one compound of metal selected from the group consisting of aluminum, titanium, silicon, zinc, magnesium, iron, chromium, cobalt, cerium and calcium, is supplied from outside of the vacuum degassing apparatus to the surface of a bubble layer formed in the molten glass to diminish or extinguish the bubble layer.

Abstract: Molten glass has a liquid level located at a higher level than lower ends of an uprising pipe and a downfalling. In addition, a contacting portion of the uprising pipe or the downfalling pipe and a brick receiver on an upstream or downstream pit for supporting the uprising or downfalling pipe, or a joint in the brick receiver is filled with sealing material.

Abstract: Molten glass has a liquid level located at a higher level than lower ends of an uprising pipe and a downfalling. In addition, a contacting portion of the uprising pipe or the downfalling pipe and a brick receiver on an upstream or downstream pit for supporting the uprising or downfalling pipe, or a joint in the brick receiver is filled with sealing material.

Abstract: 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.