Abstract: An apparatus for forming a glass sheet with reduced zircon inclusions in the glass sheet is disclosed. In one embodiment, the apparatus comprises heating elements distributed vertically between the weirs of a forming wedge and the root of the forming wedge, and wherein a thermal barrier is disposed between adjacent heating elements. A method of using the apparatus is also disclosed.

Abstract: Managing pressure within a thickness-control-zone (muffle door) housing (20) relative to pressures in a glass-making machine enclosure (60) and an upper chamber (40)—that is disposed outside the enclosure—so as to minimize or control undesired airflows that would adversely affect thickness (9) of glass ribbon (8). According to one pressure-management technique, the pressure at a location (25) in the housing (20) is managed so as to be less than the pressure at a location (65) that is within the enclosure (60) as well as both outside and adjacent to the housing. In the event of a leak, as by a crack or unintended opening in the housing, for example, this pressure difference reduces or prevents airflow toward the ribbon and, thereby, undesired thickness variation in the ribbon. According to a second pressure-management technique, the pressure at location (25) is managed so as to be greater than the pressure in the upper chamber.

Abstract: An apparatus and method for removing volatilized chemical compounds from within enclosed or partially enclosed spaces containing molten glass. One or more condensing devices are positioned within the enclosure to produce preferential condensation of the vapor on condensing elements of the condensing devices, thereby facilitating easy removal of the condensates from the enclosure. The condensing elements may have a variety of shapes and sizes depending on the design of the enclosure.

Abstract: An apparatus and method for removing volatilized chemical compounds from within enclosed or partially enclosed spaces containing molten glass. One or more condensing devices are positioned within the enclosure to produce preferential condensation of the vapor on condensing elements of the condensing devices, thereby facilitating easy removal of the condensates from the enclosure. The condensing elements may have a variety of shapes and sizes depending on the design of the enclosure.

Abstract: Disclosed is an apparatus for producing a glass sheet comprising lower thermal shields positioned below cooling doors for minimizing radiative heat loss from a forming body used to form a ribbon of molten glass from which a glass sheet is cut, and upper thermal shields positioned between the cooling doors and a root of the forming body for minimizing radiative heat loss from the forming body. The thermal shields are typically arranged as pairs and positioned on horizontally opposite sides of a flow of molten glass descending as a continuous ribbon from the forming body. Each thermal shield of the lower and upper thermal shield pairs may comprise a plurality of segments, including end segments and a central segment, wherein the end segments may be separately movable relative to the central segment, allowing an edge of the thermal shield adjacent the ribbon to be varied.

Abstract: In the formation of sheet material from molten glass, a cooling tube is positioned in the forming area for directing a flow of cooling gas on discrete portions of the molten glass proximate a draw line or root to control local thickness variations in the sheet and thereby provide a uniform glass sheet thickness across the width of the sheet. The cooling tube is disposed in a pivot member configured to rotate about at least one axis, thereby causing an end of the cooling tube to direct the cooling gas over a wide range of angular positions across a portion of the width of the molten glass flowing over and from a forming body.

Abstract: Methods and apparatus for controlling the stress in, and the shape of, the glass ribbon (15) formed in a downdraw glass manufacturing process (e.g., the fusion downdraw process) are provided. In certain embodiments, the control is achieved by cooling the bead portions (21a, 21b) of the ribbon (15) at a rate which provides a heat flux Q?b at the thickest part of the bead (23a, 23b) which is given by Q?b=Q?q+?Q?, where (i) Q?q is the heat flux at a transverse position adjacent to the bead portion (21a, 21b) at which the ribbon's thickness equals 1.05*tcenter, where tcenter is the final thickness at the ribbon's center line (17), and (ii) ?Q??(tb/tq?1)Q?q+10 kilowatts/meter2, where tb is the thickness of the thickest part of the bead portion. The cooling can take place along the entire length of the ribbon (15) or at selected locations, e.g.

Abstract: Apparatus for producing glass ribbon comprises a plurality of cooling coils positioned along a cooling axis of the apparatus extending transverse to a draw direction. The cooling coils are configured to control a transverse temperature profile of the glass ribbon along a cooling axis. Each cooling coil can be fabricated from at least one tube and configured to circulate fluid to remove heat from the cooling coil. In further examples, methods of producing a glass ribbon include the step of controlling a transverse temperature profile of the glass ribbon along a width of the glass ribbon. The step of controlling the temperature profile includes selectively removing heat from at least one of a plurality of cooling coils positioned along the cooling axis.

Abstract: A float bath for manufacturing a float glass includes a brick assembly composed of a plurality of bricks to store a molten metal so that a float glass is capable of moving forward while floating on the molten metal, a bottom casing for forming an outer side of the brick assembly, and an air blower installed away from the bottom casing to supply a cooling air toward the bottom casing. The air blower is disposed so that the cooling air is injected toward gaps between the bricks.

Abstract: Methods and apparatus for controlling the stress in, and the shape of, the glass ribbon (15) formed in a downdraw glass manufacturing process (e.g., the fusion downdraw process) are provided. In certain embodiments, the control is achieved by cooling the bead portions (21a, 21b) of the ribbon (15) at a rate which provides a heat flux Q?b at the thickest part of the bead (23a, 23b) which is given by Q?b=Q?q+?Q?, where (i) Q?q is the heat flux at a transverse position adjacent to the bead portion (21a, 21b) at which the ribbon's thickness equals 1.05*tcenter, where tcenter is the final thickness at the ribbon's center line (17), and (ii) ?Q??(tb/tq?1)Q?q+10 kilowatts/meter2, where tb is the thickness of the thickest part of the bead portion. The cooling can take place along the entire length of the ribbon (15) or at selected locations, e.g.

Abstract: Managing pressure within a thickness-control-zone (muffle door) housing (20) relative to pressures in a glass-making machine enclosure (60) and an upper chamber (40)—that is disposed outside the enclosure—so as to minimize or control undesired airflows that would adversely affect thickness (9) of glass ribbon (8). According to one pressure-management technique, the pressure at a location (25) in the housing (20) is managed so as to be less than the pressure at a location (65) that is within the enclosure (60) as well as both outside and adjacent to the housing. In the event of a leak, as by a crack or unintended opening in the housing, for example, this pressure difference reduces or prevents airflow toward the ribbon and, thereby, undesired thickness variation in the ribbon. According to a second pressure-management technique, the pressure at location (25) is managed so as to be greater than the pressure in the upper chamber.

Abstract: A method for drawing glass sheets of crystallization-sensitive glass such as borosilicate glass or glass ceramic. A melt in a vat of a glass furnace is supplied through a feed channel to a drawing chamber from which a glass sheet is drawn perpendicularly upwardly essentially across a full width of the drawing chamber. The melt in the drawing chamber is heated by at least two current-charged precious metal strips at each of the opposite sides of a drawing plane in a region of the surface of the sheet. This heating occurs in sections at each side of the drawing plans so that the melt is sectionally heated and crystallization at walls of the drawing chamber laying opposite one another at the vertical drawing plane is effectively prevented. In addition, the drawing chamber can be sectionally covered by slides.

Abstract: A method for drawing glass sheets of crystallization-sensitive glass such as borosilicate glass or glass ceramic. A melt in a vat of a glass furnace is supplied through a feed channel to a drawing chamber from which a glass sheet is drawn perpendicularly upwardly essentially across a full width of the drawing chamber. The melt in the drawing chamber is heated by at least two current-charged precious metal strips at each of the opposite sides of a drawing plane in a region of the surface of the sheet. This heating occurs in sections at each side of the drawing plans so that the melt is sectionally heated and crystallization at walls of the drawing chamber lying opposite one another at the vertical drawing plane is effectively prevented. In addition, the drawing chamber can be sectionally covered by slides.

Abstract: Molten glass 1 flows continuously from a glass melting furnace 2 to a drawing tank 7 when the glass is drawn as a continuous ribbon 10 and is passed over a bending roll 13 in a drawing chamber 8 above the tank 7 and then to a horizontal annealing lehr 14.A high yield of glass, especially thin glass, of a high standard of thickness uniformity and good planeity is promoted and facilitated by causing the molten glass 1 to flow upwardly through a slot 11 in a refractory device 12 partially immersed in molten glass in a deep drawing tank.

Abstract: An apparatus and method for the continuous production of glass articles characterized by the ability to form a single sheet of glass having two layers of different compositions, double glass panels having an air space between the panels or to produce tubes having either circular or eliptical cross-sections. The apparatus and method utilizes a molding body having a trough means which may be used to divide the glass mass into two cooperating flows over the working surfaces of an upper and lower molding body portions. The glass mass flows downwardly along an outer working surface of the upper body portion onto the inner working surfaces of the lower portion. A nozzle means provided with a ceramic shell or other refractory material may be disposed in an opening provided in the bottom portion of the molding body to provide a means for forming a closed double panel of sheet glass or a tube shaped article.

Abstract: A guide bar for stabilizing the position and orientation of a continuous sheet of flat glass being conveyed upwardly from a forming chamber comprises a transverse element located adjacent the continuous sheet of glass and spaced from it. The guide bar is preferably cooled or otherwise provided with means for controlling its temperature.

Abstract: Flat glass is produced by advancing a layer of molten glass on the surface of molten metal while cooling it sufficiently to form a continuous sheet of glass which is lifted upwardly from the surface of the supporting pool of molten metal and conveyed upwardly from it for further processing. A method is provided for selectively controlling the temperature, and thus the viscosity, of the glass of selected portions across the width of the continuous sheet of glass in order to adjust and maintain the relative lengths of the respective portions of the continuous sheet of glass as it is lifted upwardly from the supporting pool of molten metal and to thereby control the flatness of the continuous sheet of glass as it is ascending from the supporting pool of molten metal.

Abstract: In the manufacture of sheet glass by drawing a ribbon of glass upwardly from a molten glass bath via a meniscus located at the glass surface in the drawing zone, a pool of molten material is contained in the bath beneath the drawing zone by a refractory member and the molten material pool is thermally conditioned to maintain a predetermined temperature profile in at least part of the drawing zone.