A gradient fining tank and a method of operating the tank to refine foamy molten glass is disclosed. The gradient fining tank includes a floor, a roof, and two laterally-spaced sidewalls that at least partially define an interior chamber of the tank. The floor of the tank is profiled to provide the tank with an extended shallow portion that defines an inlet to the interior chamber and a deep holding portion that defines an outlet from the interior chamber. An entry section of the floor provides the extended shallow portion of the tank and a transition section and exit section of the floor provide the deep holding portion. A depth of the interior chamber at an outlet end of the deep holding portion is greater than a depth of the interior chamber at the outlet end of the extended shallow portion.

A gradient fining tank and a method of operating the tank to refine foamy molten glass is disclosed. The gradient fining tank includes a floor, a roof, and two laterally-spaced sidewalls that at least partially define an interior chamber of the tank. The floor of the tank is profiled to provide the tank with an extended shallow portion that defines an inlet to the interior chamber and a deep holding portion that defines an outlet from the interior chamber. An entry section of the floor provides the extended shallow portion of the tank and a transition section and exit section of the floor provide the deep holding portion. A depth of the interior chamber at an outlet end of the deep holding portion is greater than a depth of the interior chamber at the outlet end of the extended shallow portion.

Provided is a manufacturing method for a glass article, including: a glass melting step of continuously melting glass raw materials (Gr) in a glass melting furnace (1) by heating (electric heating) through application of a current with an electrode (11) to generate a molten glass (Gm); and a forming step of forming the molten glass (Gm) into a sheet glass by a down-draw method. The glass melting step includes adjusting a water vapor amount in an atmosphere in the glass melting furnace (1) to 15 g/Nm.sup.3 or less.

Provided is a manufacturing method for a glass article, including: a glass melting step of continuously melting glass raw materials (Gr) in a glass melting furnace (1) by heating (electric heating) through application of a current with an electrode (11) to generate a molten glass (Gm); and a forming step of forming the molten glass (Gm) into a sheet glass by a down-draw method. The glass melting step includes adjusting a water vapor amount in an atmosphere in the glass melting furnace (1) to 15 g/Nm.sup.3 or less.

A method of making glass products includes: heating material to obtain a glass melt; heating the glass melt in a melting tank having a melting tank bottom, the glass melt having a melt volume, a melt surface, and a viscosity of 10.sup.2 dPas at a temperature above 1580 C. The glass melt is heated such that at least some of the glass melt has a viscosity of 10.sup.2.5 dPas or less. An amount of thermal energy introduced directly into the melt volume is more than 60% of a total amount of thermal energy introduced into the glass melt. A maximum difference between a temperature at a location on the melt surface and a temperature at a location at the melting tank bottom vertically underneath the location on the melt surface is such that a difference in glass melt densities is less than 0.05 g/cm.sup.3 per meter distance between the locations.

A method of making glass products includes: heating material to obtain a glass melt; heating the glass melt in a melting tank having a melting tank bottom, the glass melt having a melt volume, a melt surface, and a viscosity of 10.sup.2 dPas at a temperature above 1580 C. The glass melt is heated such that at least some of the glass melt has a viscosity of 10.sup.2.5 dPas or less. An amount of thermal energy introduced directly into the melt volume is more than 60% of a total amount of thermal energy introduced into the glass melt. A maximum difference between a temperature at a location on the melt surface and a temperature at a location at the melting tank bottom vertically underneath the location on the melt surface is such that a difference in glass melt densities is less than 0.05 g/cm.sup.3 per meter distance between the locations.

A glass tank furnace having a high melting rate. The ratio of the length of the glass tank furnace to the width thereof is 2.3 to 2.8. By reducing the area of a furnace and optimizing the length-to-width ratio thereof, the heat loss of the tank furnace is reduced. By designing an appropriate liquid glass tank depth, the temperature of a furnace bottom is improved and the quality of the liquid glass is guaranteed. By providing pure oxygen burners (3) and electrodes (7), sufficient energy is guaranteed, the melting capability and the heating efficiency of the tank furnace are improved, and energy consumption and the discharge amount of carbon dioxide are significantly reduced. Weirs (5) arranged on the furnace bottom improve the outlet temperature of the liquid glass, reduce energy consumption, lower the temperature of the furnace bottom in the electrode area, prolong the service life of the furnace bottom, and guarantee an increased proportion of auxiliary power. By means of the design of bubbles (6) at the furnace bottom, the backflow strength of the liquid glass, the melting capability, and the quality of the liquid glass are improved.

A glass tank furnace having a high melting rate. The ratio of the length of the glass tank furnace to the width thereof is 2.3 to 2.8. By reducing the area of a furnace and optimizing the length-to-width ratio thereof, the heat loss of the tank furnace is reduced. By designing an appropriate liquid glass tank depth, the temperature of a furnace bottom is improved and the quality of the liquid glass is guaranteed. By providing pure oxygen burners (3) and electrodes (7), sufficient energy is guaranteed, the melting capability and the heating efficiency of the tank furnace are improved, and energy consumption and the discharge amount of carbon dioxide are significantly reduced. Weirs (5) arranged on the furnace bottom improve the outlet temperature of the liquid glass, reduce energy consumption, lower the temperature of the furnace bottom in the electrode area, prolong the service life of the furnace bottom, and guarantee an increased proportion of auxiliary power. By means of the design of bubbles (6) at the furnace bottom, the backflow strength of the liquid glass, the melting capability, and the quality of the liquid glass are improved.

A large melting furnace suitable for borosilicate glass. The melting furnace includes a melting area, a reinforcing area, an ascending area and a clarifying area. The melting area includes no furnace crown, a surface of molten glass in the melting area is not covered by any wall and exposed for feeding. The reinforcing area includes a first furnace crown, the first furnace crown includes a first partition wall and a second partition wall, and the reinforcing area and the melting area are separated by the first partition wall, and a lower end of the first partition wall goes deep below a surface of molten glass but is not in contact with a bottom of the melting furnace, so as to guarantee that the molten glass in the melting area and the reinforcing area is interconnected.

A large melting furnace suitable for borosilicate glass. The melting furnace includes a melting area, a reinforcing area, an ascending area and a clarifying area. The melting area includes no furnace crown, a surface of molten glass in the melting area is not covered by any wall and exposed for feeding. The reinforcing area includes a first furnace crown, the first furnace crown includes a first partition wall and a second partition wall, and the reinforcing area and the melting area are separated by the first partition wall, and a lower end of the first partition wall goes deep below a surface of molten glass but is not in contact with a bottom of the melting furnace, so as to guarantee that the molten glass in the melting area and the reinforcing area is interconnected.