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.

Provided is a sheet forming thickness control method of an overflow brick, including: S1: obtaining a free flow thickness distribution and a free flow speed distribution of an overflow of a glass on an overflow surface of the overflow brick through simulation; S2: calculating an equivalent drawing speed distribution of an overflow guide plate and a critical equivalent drawing speed of the overflow guide plate; S3: calculating an equivalent drawing thickness distribution and a forming thickness distribution of the overflow of the glass; S4: calculating an extreme thickness difference of a formed glass substrate; and S5: when the extreme thickness difference is greater than a preset threshold, changing current parameters and repeating steps S1 to S4; and when the extreme thickness difference is smaller than or equal to the preset threshold, processing the overflow brick and producing the glass substrate in accordance with the current parameters.

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.

An alkali-free glass substrate which is a glass substrate includes, as represented by molar percentage based on oxides, 0.1% to 10% of ZnO. The alkali-free glass substrate has an average coefficient of thermal expansion α.sub.50/100 at 50 to 100° C. of from 2.70 ppm/° C. to 3.20 ppm/° C., an average coefficient of thermal expansion α.sub.200/300 at 200 to 300° C. of from 3.45 ppm/° C. to 3.95 ppm/° C., and a value α.sub.200/300/α.sub.50/100 obtained by dividing the average coefficient of thermal expansion α.sub.200/300 at 200 to 300° C. by the average coefficient of thermal expansion α.sub.50/100 at 50 to 100° C. of from 1.20 to 1.30.

A method for forming a laminated glass article may include flowing a molten first glass composition having a first R.sub.2O concentration and a first fining agent with a first fining agent concentration. The method may also include flowing a molten second glass composition having a second R.sub.2O concentration less than the first R.sub.2O concentration of the first glass composition and a second fining agent with a second fining agent concentration that is greater than or equal to the first fining agent concentration of the first glass composition. The molten first glass composition may be contacted with the molten second glass composition to form an interface between the molten first glass composition and the molten second glass composition.

A base substrate includes a first base layer and an electrostatic resistant layer that are disposed in a stack.

A tempered glass of the present invention includes, as a glass composition, in terms of mass %, 45 to 75% of SiO.sub.2, 0 to 30% of Al.sub.2O.sub.3, and 0 to 30% of Li.sub.2O+Na.sub.2O+K.sub.2O and has a β-OH value of 0.3 to 1/mm.

Low CTE glass compositions and glass articles formed from the same are described. In one embodiment, a glass composition includes from about 60 mol. % to about 66 mol. % SiO.sub.2; from about 7 mol. % to about 10 mol. % AI.sub.2O.sub.3; and from about 14 mol. % to about 18 mol. % B.sub.2O.sub.3 as glass network formers. The glass composition may further include from about 9 mol. % to about 16 mol. % alkaline earth oxide. The alkaline earth oxide includes at least CaO. The CaO may be present in the glass composition in a concentration from about 3 mol. % to about 12 mol. %. The glass composition is free from alkali metals. The glass composition has a coefficient of thermal expansion which is less than or equal to 40×10.sup.−7/° C. averaged over the temperature range from about 20° C. to 300° C. The glass composition is particularly well suited for use as a glass cladding layer in a laminated glass article.

Provided is a glass ribbon manufacturing apparatus in which at least one of support rollers configured to support both sides of a glass ribbon (G) in a width direction in an annealing region and a cooling region is a shape stabilization roller configured to stabilize a shape of the glass ribbon (G) curved in the width direction. The shape stabilization roller includes a first roller (11) arranged on one surface side of the glass ribbon (G) and a second roller (12) arranged on another surface side of the glass ribbon (G). Inner end portions (11c) of rollers (11a) of the first roller (11) are all positioned on an outer side, in the width direction, of outer end portions (12c) of rollers (12a) of the corresponding second roller (12) in the width direction.

Methods for producing a glass ribbon include drawing a quantity of molten material from a forming vessel into a glass ribbon with the forming vessel positioned within a first portion of a housing located within an upper chamber. The methods further include drawing the glass ribbon along a draw path passing through a second portion of the housing at least partially located within a lower chamber. The methods further include venting gas from an interior of housing through a wall of the second portion of the housing. In one example, the method further includes maintaining a pressure difference between the lower chamber and the upper chamber. In another example, the method includes maintaining a pressure difference between the interior of the housing and the upper chamber.