Abstract: A disclosed glass plate is formed by converging flow streams of molten glass, which have a same composition and are caused to flow downward along left and right surfaces respectively of a forming body, in a vicinity of a root of the forming body, wherein neither front nor back surface of the glass plate is polished, wherein a convergent plane between the flow streams deviates to one side from a center plane lying at a center between the front surface of the glass plate and the back surface of the glass plate.

Abstract: An apparatus for measuring a shape profile of a surface of a sheet of material includes a light source for providing a light beam to be directed at the surface of the sheet of material, a linear translation stage coupled to the light source for translating the light source over the surface of the sheet of material such that the light beam, when directed at the surface, is incident on the surface at multiple positions and produces a reflected light beam at each of the multiple positions, a plurality of light receivers located at predetermined positions for selectively intercepting the reflected light beam produced at each of the multiple positions, a data acquisition device configured to receive information related to position difference between the light source and a selected one of the plurality of light receivers intercepting the reflected light beam produced at each of the multiple positions, and a data analysis device configured to correlate the position difference information to a shape profile of the su

Abstract: A method of manufacturing a glass sheet includes creating split flows of molten glass in a forming body (10) and causing the molten glass to flow down, subsequently merging the flows at a merging point to form a glass sheet G and causing the glass sheet to flow downward in the vertical direction. A plurality of chambers (42b, 42c, . . . ) separated by heat-insulating plates (40a, 40b, . . . ) in the direction of movement of the glass sheet G are provided. A heater (60a, 60b, . . . ) is provided for each of the chambers (42b, 42c, . . . ) so that the temperature decreases in the direction of movement. The heat-insulating plates (40a, 40b, . . . ) are disposed facing the glass sheet G, and facing surfaces of the heat-insulating plates (40a, 40b, . . . ) are shaped so as to correspond to a sheet thickness variation of the glass sheet G.

Abstract: Apparatus and method for balancing the mass flow rate of molten glass flowing over a forming body to form a glass ribbon. The apparatus comprises upper and lower transition members that surround the glass ribbon as the glass ribbon is drawn from the forming body. The upper and lower transition members are independently moveable, and separated by a gap less than 8 cm across. The narrow gap minimizes disruption to the thermal environment contained within the upper and lower transition members, and is positioned a sufficient distance above the setting zone of the ribbon to minimize any influence on the dimensional consistency of the ribbon.

Abstract: Described herein are alkali-free, boroalumino silicate glasses exhibiting desirable physical and chemical properties for use as substrates in flat panel display devices, such as, active matrix liquid crystal displays (AMLCDs). In accordance with certain of its aspects, the glasses possess good dimensional stability as a function of temperature.

Abstract: The present invention relates to a method for manufacturing a glass sheet, the method including: running down molten glass along both side surfaces of a molded body; joining and integrating the molten glass just under a lower edge part of the molded body; and drawing downward and molding an integrated sheet-shaped glass ribbon, in which a guide member which contacts to an end in a width direction of a joined molten glass is provided, and a relative position and/or a relative angle between the guide member and a lower edge of the molded body is/are adjusted.

Abstract: A sealing apparatus for use in conveying molten glass from a first vessel to a second vessel, wherein at least a portion of the first vessel is nested within the second vessel without contact between the first and second vessels, and a flexible member comprising a gas-tight seal separates an atmosphere enclosed by the sealing apparatus and an ambient atmosphere. The sealing apparatus is useful for flexibly sealing a non-contact joint between conduits for supplying molten glass to a forming body.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces.

Abstract: A method of manufacturing a glass sheet according to the present invention comprises the steps of creating split flows of molten glass in a forming body 10 and causing the molten glass to flow down, subsequently merging the flows at a merging point to form a glass sheet G and causing the glass sheet to flow downward in the vertical direction. In this method of manufacturing a glass sheet, a partition member 20 is disposed facing the glass sheet G in the vicinity of a location below the forming body 10, and a facing surface of the partition member 20 is shaped so as to correspond to a sheet thickness variation of the glass sheet G, so that a gap between the glass sheet G and the partition member 20 is substantially uniform.

Abstract: A reactive-ceramming process for making YPO4 ceramics involving the reaction between a YP-glass and a Y-source material. The invention can be used to synthesize, inter alia, phase-pure YPO4 ceramic material 5 at a relatively low temperature in a relatively short period of time and at a low cost. Invention can be used to make large piece of YPO4 blocks suitable for, e.g., an isopipe in a fusion down-draw process for making large-size glass sheets.

Abstract: A process produces a glass sheet. The process includes down-drawing a molten glass into a sheet-like glass ribbon, in which the molten glass is fed to a forming trough arranged in a forming furnace and the molten glass is caused to flow down from the forming trough through a conveyance passage extending vertically. The process also includes removing an internal strain in the glass ribbon in an annealing furnace, cooling the glass ribbon to around room temperature in a cooling chamber, and cutting the glass ribbon into a given size, in which the cooling chamber is provided with a gas exhausting passage, thereby exhausting air in the cooling chamber to an outside.

Abstract: A process produces a glass sheet. The process includes down-drawing a molten glass into a sheet-like glass ribbon, in which the molten glass is fed to a forming trough arranged in a forming furnace and the molten glass is caused to flow down from the forming trough through a conveyance passage extending vertically. The process also includes removing an internal strain in the glass ribbon in an annealing furnace, cooling the glass ribbon to around room temperature, and cutting the glass ribbon in a given size, in which a pressure in an outside atmosphere of the forming furnace and/or the annealing furnace is elevated.

Abstract: A method keeps the width of the manufactured sheet substantially the same by attaching edge directors for the formed sheet to the manufacturing apparatus structure instead of to the forming block. Thus, sheet glass may be manufactured to specification for a longer time with the same forming block. An additional method adjusts the width of the manufactured sheet by changing the distance between the edge directors. Thus sheet glass may be manufactured to different width specifications with the same forming block.

Abstract: A refractory object can include at least 10 wt % Al2O3. Further, the refractory object may contain less than approximately 6 wt % SiO2 or may include a dopant that includes an oxide of Ti, Mg, Ta, Nb, or any combination thereof. In an embodiment, at least approximately 1% of the Al2O3 in the refractory object can be provided as reactive Al2O3. In another embodiment, the refractory object may have a density of at least approximately 3.55 g/cc, a corrosion rate of no greater than approximately 2.69 mm/year, or any combination of the foregoing. In a particular embodiment, the refractory object can be used to form an Al—Si—Mg glass sheet. In an embodiment, the refractory object may be formed by a process using a compound of Ti, Mg, Ta, Nb, or any combination thereof.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces.

Abstract: The invention provides an alkali-free glass substrate small in the variation of the thermal shrinkage and a process for producing the same. An alkali-free glass substrate of the invention has an absolute value of a thermal shrinkage of 50 ppm or more when the alkali-free glass substrate is heated at a rate of 10° C./min from a room temperature, kept at a holding temperature of 450° C. for 10 hr and then cooled at a rate of 10° C./min.

Abstract: A refractory object can include at least 10 wt % Al2O3. In an embodiment, the refractory object can further include a dopant including an oxide of a rare earth element, Ta, Nb, Hf, or any combination thereof. In another embodiment, the refractory object may have a property such that the averaged grain size does not increase more than 500% during sintering, an aspect ratio less than approximately 4.0, a creep rate less than approximately 1.0×10?5 ?m/(?m×hr), or any combination thereof. In a particular embodiment, the refractory object can be in the form of a refractory block or a glass overflow forming block. The glass overflow forming block can be useful in forming an Al—Si—Mg glass sheet. In a particular embodiment, a layer including Mg—Al oxide can initially form along exposed surfaces of the glass overflow forming block when forming the Al—Si—Mg glass sheet.

Abstract: A sealing apparatus for use in conveying molten glass from a first vessel to a second vessel, wherein at least a portion of the first vessel is nested within the second vessel without contact between the first and second vessels, and a flexible member comprising a gas-tight seal separates an atmosphere enclosed by the sealing apparatus and an ambient atmosphere. The sealing apparatus is useful for flexibly sealing a non-contact joint between conduits for supplying molten glass to a forming body.

Abstract: A method keeps the width of the manufactured sheet substantially the same by attaching edge directors for the formed sheet to the manufacturing apparatus structure instead of to the forming block. Thus, sheet glass may be manufactured to specification for a longer time with the same forming block. An additional method adjusts the width of the manufactured sheet by changing the distance between the edge directors. Thus sheet glass may be manufactured to different width specifications with the same forming block.

Abstract: Isopipes (13) for making a glass or a glass-ceramic using a fusion process are provided. The isopipes are made from an alumina material which has a higher static fatigue than existing alumina materials intended for use as isopipes. In particular, the alumina materials have times-to-failure (static fatigues) of greater than one hour at 1200° C. at an applied stress of 10,000 psi. These high levels of static fatigue allow alumina isopipes to replace zircon isopipes in the manufacture of high performance glass sheets by the fusion process, including glass sheets which are incompatible with zircon isopipes but compatible with alumina isopipes, e.g., chip and scratch resistant glass sheets which have high alkali contents.

Abstract: A laminated sheet includes a surface layer having an optical surface that is of fire-polished quality and a core layer having a higher modulus than the surface layer to increase an overall stiffness or fracture toughness of the laminated sheet.

Abstract: In a method of making a glass sheet using an overflow fusion downdraw process, a glass sheet quality metric level Q1 is selected, where Q1 is a measure of allowable retardation in the glass sheet. A glass ribbon temperature T1 at which a potential glass ribbon thermal artifact could occur in a glass ribbon while the glass ribbon is being drawn through a drawing machine enclosure is identified. A thermal artifact envelope E1 is determined, where E1 contains types of glass ribbon thermal artifacts allowable at T1 and Q1. A glass melt is overflowed from an isopipe to form a glass ribbon at the root of the isopipe. The glass ribbon is drawn below the root of the isopipe through the drawing machine enclosure to form the glass sheet.

Abstract: The present invention relates to a method for manufacturing a glass sheet, the method including: running down molten glass along both side surfaces of a molded body arranged inside a molding chamber; joining and integrating the molten glass just under a lower edge part of the molded body; and drawing downward an integrated sheet-shaped glass ribbon out of an opening of the molding chamber.

Abstract: The present invention relates to a method for manufacturing a glass sheet, including: running down molten glass along both side surfaces of a molded body; joining and integrating the molten glass just under a lower edge part of the molded body; and pinching and downward delivering an end in a width direction of an integrated sheet-shaped glass ribbon by a roller pair, thereby drawing downward the glass ribbon and molding a center in the width direction of the glass ribbon to have an average thickness of 0.3 mm or less in which a pinching force is adjusted in a desired range.

Abstract: The present invention relates to a method for manufacturing a glass sheet, the method including: running down molten glass along both side surfaces of a molded body; joining and integrating the molten glass just under a lower edge part of the molded body; and drawing downward and molding an integrated sheet-shaped glass ribbon, in which a guide member which contacts to an end in a width direction of a joined molten glass is provided, and a relative position and/or a relative angle between the guide member and a lower edge of the molded body is/are adjusted.

Abstract: A process and apparatus for cutting a continuous glass ribbon involving the use of edge restrainers such as suction cups and clamps connected to an actuator of a robot tooling through a flexible linkage capable of reciprocal motion in the direction of the ribbon velocity. The use of the flexible linkage reduces peak pulling-force when the glass ribbon is pulled or pushed laterally to during bending and separation along a pre-formed score-line. The invention can be advantageously used in the bottom of the draw of a vertical down-draw forming process.

Abstract: An apparatus for making a glass sheet using overflow fusion down-draw process comprising an inlet assembly having an elliptic cylindrical section coupled to a transition section which is, in turn, coupled to an open end of an open channel of an isopipe, and an overflow fusion down-draw process for making glass sheet. The glass melt flow has a high surface velocity profile conducive to the formation of a glass ribbon over the surface of the weirs and the wedge side surfaces with the desired mass distribution.

Abstract: A substrate (100) comprising a sheet of either a glass, a glass ceramic, or a ceramic and having increased edge strength. A polymeric edge coating (120) prevents creation of strength limiting defects along the edges of the substrate and protects the bend strength of the edges. The substrate may also have at least two parallel high strength edges (110, 112) and an edge coating (120) of a polymeric material covering at least a portion of each of the high strength edges to preserve the high strength edges from the introduction of defects and damage to the edges. Each of the two parallel high strength edges has a bend strength that is capable of less than about 2% failure probability at a stress level of 200 MPa over a test length of 50 mm. A method of making the substrate is also provided.

Abstract: The present invention discloses improved methods and apparatus for forming sheet glass. In one embodiment, the invention introduces a counteracting force to the stresses on the forming structure in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming structure.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces. In an alternative embodiment, the glass is preferentially cooled across its width to create forming stresses during solidification, which ensures that the glass sheet drawn is inherently flat.

Abstract: The present invention significantly modifies “The Overflow Process”. It includes a method and apparatus for measuring glass flow rate and maintaining a constant glass flow rate. It also embodies design features and methods that support and stress the forming apparatus in a manner such that the deformation that results from thermal creep is corrected, thus minimizing the effect of the thermal creep on the thickness variation of the glass sheet. The present invention also embodies design features that change the process from a single step (combined flow distribution and cooling) to a two step process; step one being flow distribution and step two being cooling.

Abstract: Methods for reducing stress on an isopipe during manufacture of a drawn glass sheet are disclosed including a method comprising providing an isopipe having a root, heating the isopipe to a predetermined temperature, maintaining the isopipe at the predetermined temperature for a period of time sufficient to relieve at least a portion of a tensile stress on the isopipe root, coupling the isopipe to a down-comer, and then providing glass to the isopipe. Also disclosed is a method comprising heating an isopipe such that the temperature difference between the weir and the root of the isopipe, after heating and prior to coupling, is less than about 100° C. A method comprising application of a compressive force to the ends of an isopipe root during heating is also disclosed.

Abstract: Disclosed is an isopipe for use in the manufacture of sheet glass by, and more specifically to an isopipe designed to control sag during use, as well as a method for reducing the sag of an isopipe used in a fusion process for molten glass. In one embodiment, the isopipe comprises a cavity that extends at least partially through the refractory body of the isopipe along its longitudinal length. The cavity has varying cross-sections configured such that, for at least a portion of the length of the isopipe, the load bending moment is greater than or generally equal to the gravity bending moment. In one embodiment, the neutral axis varies along the length of the cavity and has a similar profile to that of the gravity bending moment diagram.

Abstract: An element sealed body comprises a glass substrate, an element mounted on the glass substrate, and a protective glass for sealing the element, wherein a surface of the protective glass and a surface of the glass substrate, which are brought into contact with each other, have a surface roughness Ra of 2.0 nm or less respectively.

Abstract: Isopipes for use in making sheet glass by a fusion process are provided which exhibit reduced sag. The isopipes are composed of a zircon refractory which has a mean creep rate (MCR) at 1180° C. and 250 psi and a 95 percent confidence band (CB) for said mean creep rate such that the CB to MCR ratio is less than 0.5, the MCR and the CB both being determined using a power law model. The zircon refractory can contain titania (TiO2) at a concentration greater than 0.2 wt % and less than 0.4 wt %. A concentration of titania in this range causes the zircon refractory to exhibit a lower mean creep rate than zircon refractories previously used to make isopipes. In addition, the variation in mean creep rate is also reduced which reduces the chances that the zircon refractory of a particular isopipe will have an abnormally high creep rate and thus exhibit unacceptable sag prematurely.

Abstract: A method keeps the width of the manufactured sheet substantially the same by attaching edge directors for the formed sheet to the manufacturing apparatus structure instead of to the forming block. Thus, sheet glass may be manufactured to specification for a longer time with the same forming block. An additional method adjusts the width of the manufactured sheet by changing the distance between the edge directors. Thus sheet glass may be manufactured to different width specifications with the same forming block.

Abstract: A method of minimizing distortion in a glass sheet manufacturing process wherein the stress in a parent sheet of glass is measured along each edge of the sheet. The stress data is then used to develop a distortion predictor for predicting the in-plane distortion which sub-sheets of the parent sheet are likely to exhibit when the parent sheet is cut into pre-determined sizes. The in-plane distortion may be predicted based on criteria established by the glass manufacturer, or supplied by an original equipment manufacturer (OEM).

Abstract: Isopipes for use in making sheet glass by a fusion process are provided which exhibit reduced sag. The isopipes are composed of a zircon refractory which has a mean creep rate (MCR) at 1180° C. and 250 psi and a 95 percent confidence band (CB) for said mean creep rate such that the CB to MCR ratio is less than 0.5, the MCR and the CB both being determined using a power law model. The zircon refractory can contain titania (TiO2) at a concentration greater than 0.2 wt % and less than 0.4 wt %. A concentration of titania in this range causes the zircon refractory to exhibit a lower mean creep rate than zircon refractories previously used to make isopipes. In addition, the variation in mean creep rate is also reduced which reduces the chances that the zircon refractory of a particular isopipe will have an abnormally high creep rate and thus exhibit unacceptable sag prematurely.

Abstract: A laminated sheet includes a surface layer having an optical surface that is of fire-polished quality and a core layer having a higher modulus than the surface layer to increase an overall stiffness or fracture toughness of the laminated sheet.

Abstract: A pull roll assembly is described herein that is used to draw a glass sheet. The pull roll assembly includes a first roll assembly, a second roll assembly and a device (e.g., differential drive, sensor(s)). The device enables one to control the first and/or second roll assemblies based in part on pulling forces (e.g., glass contact normal force and/or required sheet pulling force) associated with a glass sheet while the glass sheet is being drawn between the first and second roll assemblies. A glass manufacturing system and method for using the pull roll assembly are also described herein.

Abstract: A molten glass delivery system for use in producing sheet glass by a fusion process is provided. The delivery system includes a first conduit (9) which surrounds a portion of a second conduit (19) with a free surface (21) of molten glass (31) being formed between the two conduits. The first (9) and second (19) conduits are positioned with respect to one another so that the spatial relationship between the exit end (20) of the second conduit (19) and the free surface (21) results in neither substantial numbers of devitrification defects (27, 29) nor substantial numbers of blister defects (35) in finished sheets of devitrification sensitive glass, e.g., high silica LCD glass.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces. In an alternative embodiment, the glass is preferentially cooled across its width to create forming stresses during solidification, which ensures that the glass sheet drawn is inherently flat.

Abstract: Methods of manufacturing glass sheets with manufacturing systems that including platinum-containing components are provided. The method includes providing a barrier coating to reduce the hydrogen permeability of the platinum-containing components which reduces the propensity for blistering of glass sheets made using the components.

Abstract: The forming apparatus of the present invention preferably includes an orifice on top of the trough. The uniquely shaped orifice substitutes for the weirs as the controlling entity for glass thickness. The orifice is designed such that as it deforms, it maintains a linear flow characteristic with respect to its length. As the orifice is made larger by the applied stress, the percentage width increase is the same over its length and consequently the percentage flow increase is the same over the length of the orifice. In another embodiment, the present invention provides an adjustment to change the flow characteristics of the trough to compensate for the degradation of the forming trough during an extended production run. A flow control plug can be inserted into the trough, such that flow dynamics can be altered during hot operation by insertion, removal or position adjustment of the flow control plug.

Abstract: A system and method for suppressing the formation of gaseous inclusions in glass sheets and the resulting glass sheets are described herein. The system includes a melting, fining, delivery, mixing or forming vessel that has a refractory metal component (e.g., platinum component) which has an inner wall that contacts molten glass and an outer wall coated with an oxygen ion transportable material (e.g., zirconia) which is coated with a conductive electrode. The system also includes a DC power source that supplies DC power across the oxygen ion transportable material which causes oxygen ions to migrate from the refractory metal component to the conductive electrode and enables one to control the partial pressure of oxygen around an exterior of the vessel which helps one to effectively prevent hydrogen permeation from the molten glass in order to suppress the formation of undesirable gaseous inclusions and surface blisters within the glass sheet.

Abstract: The present invention alters the flow path at the inlet of the sheet glass forming apparatus to improve quality. The bottom of the downcomer pipe is preferably shaped to alter the character of the vortex flow in the quiescent flow zone between the pipes. In another embodiment, a bead guide provides hydraulic stresses that are in opposition to the surface tension stress and thus reduces the influence of surface tension on the formation of thick beads on the edges of the sheet. The present invention also measures the temperature of the glass by immersing thermocouples in the glass, at locations where any defects caused by the immersion are in the glass that forms the unusable edges of the sheet. In another embodiment, the support structure for the trough is altered to substantially reduce the aging of the trough due to thermal creep.

Abstract: The present invention alters the flow path at the inlet of the sheet glass forming apparatus to improve quality. The bottom of the downcomer pipe is preferably shaped to alter the character of the vortex flow in the quiescent flow zone between the pipes. In another embodiment, a bead guide provides hydraulic stresses that are in opposition to the surface tension stress and thus reduces the influence of surface tension on the formation of thick beads on the edges of the sheet. The present invention also measures the temperature of the glass by immersing thermocouples in the glass, at locations where any defects caused by the immersion are in the glass that forms the unusable edges of the sheet. In another embodiment, the support structure for the trough is altered to substantially reduce the aging of the trough due to thermal creep.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces. In an alternative embodiment, the glass is preferentially cooled across its width to create forming stresses during solidification, which ensures that the glass sheet drawn is inherently flat.

Abstract: The present invention alters the flow path at the inlet of the sheet glass forming apparatus to improve quality. The bottom of the downcomer pipe is preferably shaped to alter the character of the vortex flow in the quiescent flow zone between the pipes. In another embodiment, a bead guide provides hydraulic stresses that are in opposition to the surface tension stress and thus reduces the influence of surface tension on the formation of thick beads on the edges of the sheet. The present invention also measures the temperature of the glass by immersing thermocouples in the glass, at locations where any defects caused by the immersion are in the glass that forms the unusable edges of the sheet. In another embodiment, the support structure for the trough is altered to substantially reduce the aging of the trough due to thermal creep.

Abstract: The disclosure teaches design features that can be used alone or in combination to facilitate faster, more uniform flow of glass through the apparatus and allows the thickness of the sheet to be adjusted. An overflow device is provided at the far end of the trough and is used in conjunction with tilting of the apparatus to expand the range of glass flow rate and glass viscosity for which this invention will produce satisfactory product. The forming apparatus can be made with non-linear weirs and the trough bottom to provide a greater range of flow rates. The glass flow in the inflow pipe can modulated or a contoured trough cross-section used to provide more uniform time dependent flow for forming the sheet. The forming apparatus can include an orifice on top of the trough and glass can be moved through the apparatus using pressure. Additional orifices can be provided on the bottom or sides to allow greater variability in sheet thickness.