Method and apparatus for preventing bubble nucleation and growth in a molten glass delivery facility

Claim 2

In an apparatus for delivering molten glass onto a pool of molten tin-containing metal for forming into flat glass which includes a glass-supporting, silica-containing refractory member for supporting molten glass immediately prior to its delivery onto the molten metal which member is contacted by glass and tin, the improvement comprising a semi-adherent glaze of glass which behaves as a viscous liquid at molten glass delivery temperatures disposed on glass and tin-contacting surfaces of the silica-containing refractory member wherein said glass is disposed on such surfaces prior to first contact by molten glass being delivered thereover.

Claim 3

The apparatus according to claim 1 wherein the glaze is a silica-containing glass.

Claim 4

In a method of preparing a flat glassmaking apparatus for use in the manufacture of flat glass by delivering molten glass over a glass-supporting, silica-containing refractory member to a forming chamber onto a glass-supporting surface of a pool of molten tin-containing metal and thereafter cooling and forming the glass into a continuous sheet of glass, wherein the glass-supporting refractory is mounted in place, the forming chamber and refractory are heated to a temperature within range sufficient to provide a pool of the metal in a molten state and for receiving molten glass, providing a protective atmosphere in the forming chamber and initiating the flow of molten glass over the glass-supporting refractory and onto the pool of molten metal; the improvement comprising establishing on glass and tin-contacting surfaces of the glass-supporting refractory a glaze of glass which becomes viscous at the temperature to which the refractory is heated prior to initiation of molten glass flow; and maintaining the temperature of the glass-supporting refractory sufficient during initial molten glass flow to permit a portion of the glaze to slough off from the glass-supporting refractory and be removed by adherence to the molten glass.

Claim 5

In a method of preparing a flat glassmaking apparatus for use in the manufacture of flat glass by delivering molten glass over a glass-supporting, silica-containing refractory member to a forming chamber onto a glass-supporting surface of a pool of molten tin-containing metal and thereafter cooling and forming the glass into a continuous sheet of glass, wherein the glass-supporting refractory is mounted in place, the forming chamber and refractory are heated to a temperature within range sufficient to provide a pool of the metal in a molten state and for receiving molten glass, providing a protective atmosphere in the forming chamber and initiating the flow of molten glass over the glass-supporting refractory and onto the pool of molten metal; the improvement comprising establishing on glass and tin-contacting surfaces of the glass-supporting refractory a glaze of glass which becomes viscous at the temperature to which the refractory is heated prior to initiation of molten glass flow; and maintaining the temperature of the glass-supporting refractory sufficient during initial molten glass flow to permit a portion of the glaze to slough off from the glass-supporting refractory and be removed by adherence to the molten glass.

Claim 6

The method according to claim 3 wherein the glass is a silica-containing glass.

Claim 7

The method according to claim 4 wherein the glaze of silica-containing glass is established as an essentially sulfate-free glaze.

Claim 8

The method according to claim 3 wherein the glaze of glass is established with a thickness of from about 0.005 to 0.5 inch prior to heating in preparation for receiving molten glass.

Claim 9

The method according to claim 3 wherein substantially all exposed surfaces of the glass-supporting refractory have the glaze of glass established on them.