A glass-ceramic that includes: SiO.sub.2 from about 35 mol % to about 80 mol %; B.sub.2O.sub.3 from about 10 mol % to about 50 mol %; P.sub.2O.sub.5 from about 10 mol % to about 50 mol %; and an optional addition of one or more of CaO, MgO and Bi.sub.2O.sub.3 from 0 mol % to about 5 mol %, wherein the glass-ceramic further comprises a boron-phosphate crystalline phase.

A method includes heating a glass preform having a plurality of glass layers and drawing the glass preform in a distal direction to form a drawn glass sheet extending distally from the glass preform and having the plurality of glass layers. The drawn glass sheet is thinner than the glass preform. The drawn glass sheet can be rolled onto a collection spool. At least a portion of a glass layer can be removed from the drawn glass sheet. An exemplary glass sheet includes a first glass layer, a second glass layer adjacent to the first glass layer, and a thickness of at most about 0.1 mm. An exemplary ion exchanged glass sheet includes a thickness of at most about 0.1 mm and a surface layer that is under a compressive stress and extends into an interior of the glass sheet to a depth of layer.

A glass manufacturing apparatus includes a vessel and a filter positioned to receive a beam of light. The filter passes a second wavelength component of the beam of light through the filter while preventing a first wavelength component from the beam of light from passing through the filter. The glass manufacturing apparatus comprises a sensor positioned to receive the second wavelength component that has passed through the filter and that has been reflected within the vessel. Additionally, methods of determining a level of molten material within a glass manufacturing apparatus and methods of manufacturing glass are provided.

A method of making a glass sheet comprises laminating a high CTE core glass to a low CTE clad glass at high temperatures and allowing the laminate to cool creating compressive stress in the clad glass, and then ion exchanging the laminate to increase the compressive stress in the outer near surface regions of the clad glass. The core glass may include ions that exchange with ion in the clad glass to increase the compressive stress in inner surface regions of the clad glass adjacent to the clad glass/core glass interfaces. The glass laminate may be formed and laminated using a fusion forming and laminating process and fusion formable and ion exchangeable glass compositions.

A laminated glass article includes a core layer and a clad layer directly adjacent to the core layer. The core layer is formed from a core glass composition. The clad layer is formed from a clad glass composition. An average clad coefficient of thermal expansion (CTE) is less than an average core CTE such that the clad layer is in compression and the core layer is in tension. A compressive stress of the clad layer decreases with increasing distance from an outer surface of the clad layer within an outer portion of the clad layer and remains substantially constant with increasing distance from the outer surface of the clad layer within an intermediate portion of the clad layer disposed between the outer portion and the core layer. A thickness of the intermediate portion of the clad layer is at least about 82% of a thickness of the clad layer.

A method of controlling a flowrate of molten material at a downstream location in a glass manufacturing process can include mixing the molten material at an upstream location positioned upstream from the downstream location relative to a flow direction of the molten material with a shaft including a plurality of protrusions. The method can also include measuring a torque of the shaft, measuring a level of the molten material at the upstream location, and calculating a viscosity of the molten material at the upstream location based on the measured torque and the measured level. In addition, the method can include estimating the flowrate based on the calculated viscosity, and controlling the flowrate at the downstream location based on the estimated flowrate.

Apparatus can comprise a conduit with at least one slot of a plurality of slots comprising an intermediate length including a maximum width that is less than a maximum width of a first end portion and/or a maximum width of a second end portion of the slot. In some embodiments, methods produce a glass ribbon with an apparatus comprising at least one slot within a peripheral wall of a conduit. In some embodiments, methods are provided for determining a volumetric flow profile dQ(x)/dx of molten material flowing through a slot in a peripheral wall of a conduit. In some embodiments, methods and apparatus provide a slot extending through an outer peripheral surface of a peripheral wall of a conduit that can comprise a width profile d(x) along a length of the slot to achieve a predetermined volumetric flow profile dQ(x)/dx of molten material through the slot.

A manufacturing method for a band-shaped glass film (GF) includes use of: a plurality of rollers (10) configured to change a direction of the falling band-shaped glass film (GF) to a horizontal direction; and a first horizontal-conveyance unit (4) configured to convey the band-shaped glass film (GF) in the horizontal direction after the changing of the direction of the band-shaped glass film (GF). After a lower end of the band-shaped glass film (GF) passes through a position between the plurality of rollers (10) being at a retreated position (P2) and the first horizontal-conveyance unit (4), the plurality of rollers (10) are moved from the retreated position (P2) to a regular position (P1) to apply a pressing force to the band-shaped glass film (GF), to thereby cut the band-shaped glass film (GF) along a width direction by bend-breaking.

Methods for making a glass article are described that include flowing molten glass through a metallic vessel, and supplying alternating electrical currents to multiple electrical circuits, each electrical circuit including a power supply, a pair of adjacent electrical flanges connected to the power supply, and a portion of the metallic vessel extending between and in electrical communication with the pair of adjacent flanges. At least two adjacent electrical circuits of the multiple electrical circuits share an electrical flange that is a common electrical path for the two adjacent electrical circuits, the two adjacent electrical circuits being supplied with alternating electrical currents, wherein at least one of the electrical currents is cut by a phase-fired controller.

A method for producing a flat thin glass ribbon is provided. The method includes the steps of drawing melted glass downward away from a tank in a pulling direction while applying tensile forces which act in the pulling direction to form the thin glass ribbon having a thickness of at most 250 μm and cooling the thin glass ribbon until a temperature of the thin glass ribbon undershoots a glass transition temperature. The tensile forces are transferred to the thin glass ribbon by at least two pairs of drawing rollers. The at least two pairs of drawing rollers are spaced apart transversely to the pulling direction and contact the thin glass ribbon on longitudinal edges of the thin glass ribbon. The thin glass ribbon only makes contact with the at least two pairs of drawing rollers at a position where the temperature of the thin glass ribbon is at most at or below 500° C.