Apparatus, systems and methods for refining molten glass include a fining chamber having a refractory floor and a sidewall structure that may include a refractory liner, and includes an inlet transition region having increasing width from initial to a final width, and depth decreasing from an initial to final depth. The floor includes a raised curb having width equal to final width of the inlet transition region, curb length less than the length of the inlet transition region, and curb height forming a shallowest depth portion of the fining chamber. The raised curb separates the fining chamber into the inlet transition region and a primary fining region, the primary fining region defined by the refractory floor and sidewall structure. The primary fining region has a constant depth greater than the shallowest depth but less than the depth of the inlet transition region.

Apparatus, systems and methods for refining molten glass include a fining chamber having a refractory floor and a sidewall structure that may include a refractory liner, and includes an inlet transition region having increasing width from initial to a final width, and depth decreasing from an initial to final depth. The floor includes a raised curb having width equal to final width of the inlet transition region, curb length less than the length of the inlet transition region, and curb height forming a shallowest depth portion of the fining chamber. The raised curb separates the fining chamber into the inlet transition region and a primary fining region, the primary fining region defined by the refractory floor and sidewall structure. The primary fining region has a constant depth greater than the shallowest depth but less than the depth of the inlet transition region.

A glass substrate of the present invention has a temperature at a viscosity at high temperature of 10.sup.2.5 dPa.Math.s of 1,650° C. or less, and an estimated viscosity Log η.sub.500 at 500° C. of 26.0 or more calculated by the equation Log η.sub.500=0.167×Ps−0.015×Ta−0.062×Ts−18.5.

Submerged combustion glass manufacturing systems and methods include a melter having a floor, a roof, a wall structure connecting the floor and roof, and one or more submerged combustion burners mounted in the floor, roof, and/or wall structure discharging combustion products including water vapor under a level of material being melted in the melter and create turbulent conditions in the material. The floor, roof, or wall structure may include fluid-cooled refractory material and an optional metallic external shell, or the metallic shell may include coolant passages. One or more conduits drain water condensed from the water vapor from regions of refractory material substantially saturated with the water, and/or from burner supports.

Low-carbon monolithic refractories are provided. Methods of manufacturing glass employing low-carbon monolithic refractories are also provided. Methods and apparatuses for glass manufacture for reducing the formation of carbon dioxide blisters during glass manufacture are also provided.

Low-carbon monolithic refractories are provided. Methods of manufacturing glass employing low-carbon monolithic refractories are also provided. Methods and apparatuses for glass manufacture for reducing the formation of carbon dioxide blisters during glass manufacture are also provided.

A process for producing a refractory material for use in the superstructure of glass melting tanks contains, as main components, SiO.sub.2, SiC and a binder or binder mixture. A particulate substance, which in the spectral range from 1 μm to 5 μm and at temperatures above 1000° C. has a spectral emission capability which is higher than the spectral emission capability of the matrix of the refractory material, is incorporated into the matrix of the refractory material. A method of increasing the spectral emissivity of shaped, fired, refractory materials, is also provided.

A process for producing a refractory material for use in the superstructure of glass melting tanks contains, as main components, SiO.sub.2, SiC and a binder or binder mixture. A particulate substance, which in the spectral range from 1 μm to 5 μm and at temperatures above 1000° C. has a spectral emission capability which is higher than the spectral emission capability of the matrix of the refractory material, is incorporated into the matrix of the refractory material. A method of increasing the spectral emissivity of shaped, fired, refractory materials, is also provided.

Isopipes (13) for making glass sheets using a fusion process are provided. The isopipes are made from alumina materials which have low levels of the elements of group IVB of the periodic chart, i.e., Ti, Zr, and Hf, as well as low levels of Sn. In this way, the alumina isopipes can be used with glasses that contain tin (e.g., as a fining agent or as the result of the use of tin electrodes for electrical heating of molten glass) without generating unacceptable levels of tin-containing defects in the glass sheets, specifically, at the sheets' fusion lines. The alumina isopipes disclosed herein are especially beneficial when used with tin-containing glasses that exhibit low tin solubility, e.g., glasses that have (RO+R.sub.2O)/Al.sub.2O.sub.3 ratios between 0.9 and 1.1, where, in mole percent on an oxide basis, (RO+R.sub.2O) is the sum of the concentrations of the glass' alkaline earth and alkali metal oxides and Al.sub.2O.sub.3 is the glass' alumina concentration.

Isopipes (13) for making glass sheets using a fusion process are provided. The isopipes are made from alumina materials which have low levels of the elements of group IVB of the periodic chart, i.e., Ti, Zr, and Hf, as well as low levels of Sn. In this way, the alumina isopipes can be used with glasses that contain tin (e.g., as a fining agent or as the result of the use of tin electrodes for electrical heating of molten glass) without generating unacceptable levels of tin-containing defects in the glass sheets, specifically, at the sheets' fusion lines. The alumina isopipes disclosed herein are especially beneficial when used with tin-containing glasses that exhibit low tin solubility, e.g., glasses that have (RO+R.sub.2O)/Al.sub.2O.sub.3 ratios between 0.9 and 1.1, where, in mole percent on an oxide basis, (RO+R.sub.2O) is the sum of the concentrations of the glass' alkaline earth and alkali metal oxides and Al.sub.2O.sub.3 is the glass' alumina concentration.