Glass melting furnaces and vessels with improved electrical resistivity

Abstract

The glass melting furnace includes a melting tank having a bed, a feeding mechanism configured to feed raw materials to the melting tank, a heating mechanism configured to convert the raw materials fed to the melting tank into molten glass, and a layer including an electrical resistivity enhancing material configured to diffuse into at least one layer of the bed including a refractory ceramic material.

Description

Description of Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Patent Application No. 63 / 313,883, filed February 25, 2022, the contents of which are relied upon and incorporated herein by reference in their entirety. [Technical field]

[0002] FIELD OF THE DISCLOSURE This disclosure relates generally to glass melting furnaces and vessels, and more particularly to glass melting furnaces and vessels having improved electrical resistivity. [Background technology]

[0003] In the manufacture of glass articles such as glass sheets for display applications including televisions and portable devices such as phones and tablets, glass compositions are typically melted in a melting tank. During operation of the melting tank over the course of a production run, hot spots can develop in certain areas of the melting tank, which over time can cause degradation of the melting tank material, eventually resulting in a phenomenon known as "fire through," which can ultimately result in mechanical failure of the melting tank material. When such an event occurs, it can result in significant disruptions to production, as well as substantial repair costs. Summary of the Invention [Problem to be solved by the invention]

[0004] It would therefore be desirable to minimize the occurrence of such events. [Means for solving the problem]

[0005] An embodiment disclosed herein includes a glass melting tank comprising a heating mechanism and a bed, the bed including at least one layer including a refractory ceramic material, the bed also including a layer including an electrical resistivity enhancing material, the electrical resistivity enhancing material configured to diffuse into the at least one layer including the refractory ceramic material during operation of the glass melting tank.

[0006] Embodiments disclosed herein also include a method of operating a glass melting tank. The glass melting tank includes a bed including at least one layer including a refractory ceramic material. The bed also includes a layer including an electrical resistivity enhancing material. The method includes providing raw materials to the melting tank. The method also includes converting the raw materials provided to the melting tank into molten glass. Additionally, the method includes diffusing the electrical resistivity enhancing material into the at least one layer including the refractory ceramic material during operation of the glass melting tank.

[0007] Additional features and advantages of the embodiments disclosed herein are set forth in the following detailed description, and in part will be readily apparent to those skilled in the art from that description, or may be learned by practicing the embodiments of the disclosure as described herein, including the following detailed description, claims, and accompanying drawings.

[0008] It is to be understood that both the foregoing general description and the following detailed description present embodiments that are intended to provide an overview or framework for understanding the nature and characteristics of the claimed embodiments. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the present disclosure and, together with the description, serve to explain the principles and operation thereof. [Brief description of the drawings]

[0009] [Figure 1] Illustrative diagram of an exemplary fusion downdraw glass manufacturing apparatus and process [Diagram 2] FIG. 1 is a side cutaway view of an exemplary glass melting tank according to embodiments disclosed herein. [Diagram 3] FIG. 3 is a top cutaway view of the exemplary glass melting tank of FIG. [Figure 4] 2-3 are cutaway end views of the exemplary glass melting tanks. [Diagram 5] 5 is a bottom cutaway view of the exemplary glass melting tank of FIGS. [Figure 6]FIG. 1 is a side cutaway view of an exemplary glass melting tank floor according to embodiments disclosed herein; [Figure 7] FIG. 1 is a side cutaway view of an exemplary glass melting tank floor according to embodiments disclosed herein; [Figure 8] Top cutaway of part of the floor in Figure 7 [Figure 9] FIG. 1 is a side cutaway view of an exemplary glass melting tank floor according to embodiments disclosed herein; [Figure 10] FIG. 1 is a side cutaway view of an exemplary glass melting tank floor according to embodiments disclosed herein; [Figure 11] FIG. 1 is an end cutaway view of a floor area of ​​an exemplary glass melting tank according to embodiments disclosed herein; [Figure 12] Top cutaway of part of the floor in Figure 11 [Figure 13] FIG. 1 is an end cutaway view of an exemplary glass melting tank floor according to embodiments disclosed herein; [Figure 14] Top cutaway of part of the floor in Figure 13 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0011] Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, for example by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0012] Any directional terms used herein - e.g., up, down, right, left, front, back, upper and bottom - are used only with reference to the drawings depicted and are not intended to imply absolute orientation.

[0013] Unless otherwise expressly stated, it is never intended that any method described herein be construed as requiring that its steps be performed in a particular order, or that any particular orientation of any apparatus be required. Thus, where a method claim does not actually recite an order in which its steps must be followed, or an apparatus claim does not actually recite an order or orientation for individual components, or where it is otherwise specifically stated in the claim or description that the steps are to be limited to a particular order, or where a particular order or orientation for the apparatus components is not recited, no order or orientation is ever intended to be implied. This applies to any possible non-expressive criteria of interpretation, including sequence of steps, flow of operations, order of components, or orientation of components; obvious meanings derived from grammatical construction or punctuation; and logical matters regarding the number or type of embodiments described in the specification.

[0014] As used herein, nouns include plural referents unless the context clearly indicates otherwise. Thus, for example, a reference to a component includes aspects having two or more of such components unless the context clearly indicates otherwise.

[0015] As used herein, the term "heating mechanism" refers to a mechanism that provides heat to the glass melting furnace and / or melting tank, such as by the action of electrodes, combustion burners, or both.

[0016] As used herein, the term "electrical resistivity enhancing material" refers to a material that increases the electrical resistivity of a material or layer of material into which it is incorporated, such as increased electrical resistivity of the material or layer of material during the operating conditions of a glass melting furnace and / or melting tank.

[0017] An example glass manufacturing apparatus 10 is shown in FIG. 1. In some cases, the glass manufacturing apparatus 10 may include a glass melting furnace 12, which may include a melting tank 14. The glass melting furnace 12, including the melting tank 14, may include one or more additional components, such as heating elements or mechanisms (e.g., combustion burners and electrodes) that heat the raw materials and convert the raw materials into molten glass. In further examples, the glass melting furnace 12 may include thermal management devices (e.g., insulating components) that reduce heat lost from the vicinity of the melting tank. In yet further examples, the glass melting furnace 12 may include electronic and / or electromechanical devices that facilitate melting of the raw materials into a glass melt. Still further, the glass melting furnace 12 may include a support structure (e.g., a support chassis, support members, etc.) or other components.

[0018] The glass melting tank 14 is typically made from a refractory material, such as a refractory ceramic material including alumina or zirconia. In some cases, the glass melting tank 14 may be constructed from refractory ceramic bricks. Specific embodiments of the glass melting tank 14 are described in more detail below.

[0019] In some cases, the glass melting furnace may be incorporated as a component of a glass manufacturing apparatus for producing glass substrates, e.g., continuous lengths of glass ribbons. In some cases, the glass melting furnace of the present disclosure may be incorporated as a component of a glass manufacturing apparatus including a slot draw apparatus, a float bath apparatus, a downdraw apparatus such as a fusion process, an updraw apparatus, a rolling apparatus, a tube drawing apparatus, or any other glass manufacturing apparatus that would benefit from the embodiments disclosed herein. As an example, FIG. 1 illustrates a schematic of a glass melting furnace 12 as a component of a fusion downdraw glass manufacturing apparatus 10 for fusion drawing a glass ribbon for subsequent processing into individual glass sheets.

[0020] The glass manufacturing system 10 (e.g., the fusion downdraw system 10) may optionally include upstream glass manufacturing equipment 16 positioned upstream relative to the glass melting tank 14. In some cases, some or all of the upstream glass manufacturing equipment 16 may be incorporated as part of the glass melting furnace 12.

[0021] As shown in the illustrated example, the upstream glass manufacturing apparatus 16 may include a storage vessel 18, a raw material supply 20, and a motor 22 connected to the raw material supply. The storage vessel 18 may be configured to store a quantity of raw material 24 that may be supplied to the melting tank 14 of the glass melting furnace 12, as indicated by arrow 26. The raw material 24 typically includes one or more glass-forming metal oxides and one or more modifiers. In some cases, the raw material supply 20 may be driven by the motor 22 such that the raw material supply 20 delivers a predetermined amount of the raw material 24 from the storage vessel 18 to the melting tank 14. In a further example, the motor 22 may drive the raw material supply 20 to introduce the raw material 24 at a controlled rate based on a level of molten glass sensed downstream of the melting tank 14. The raw material 24 in the melting tank 14 may then be heated to form molten glass 28.

[0022] The glass manufacturing apparatus 10 may optionally include downstream glass manufacturing apparatus 30 located downstream relative to the glass melting furnace 12. In some cases, a portion of the downstream glass manufacturing apparatus 30 may be incorporated as part of the glass melting furnace 12. In some cases, the first connecting conduit 32, described below, or other portions of the downstream glass manufacturing apparatus 30 may be incorporated as part of the glass melting furnace 12. The elements of the downstream glass manufacturing apparatus, including the first connecting conduit 32, may be formed from a precious metal. Suitable precious metals include platinum group metals selected from the group of metals consisting of platinum, iridium, rhodium, osmium, ruthenium, and palladium, or alloys thereof. For example, the downstream components of the glass manufacturing apparatus may be formed from a platinum-rhodium alloy including about 70% to about 90% platinum and about 10% to about 30% rhodium, by weight. However, other suitable metals may include molybdenum, palladium, ruthenium, tantalum, titanium, tungsten, and alloys thereof.

[0023] The downstream glass making apparatus 30 may include a first conditioning (i.e., processing) vessel, such as a fining vessel 34, located downstream of the melting vessel 14 and connected to the melting vessel 14 by the first connecting conduit 32 described above. In some cases, the molten glass 28 may be gravity fed from the melting vessel 14 to the fining vessel 34 by the first connecting conduit 32. For example, gravity may cause the molten glass 28 to pass from the melting vessel 14 to the fining vessel 34 through the internal passage of the first connecting conduit 32. However, other conditioning vessels may be located downstream of the melting vessel 14, for example, between the melting vessel 14 and the fining vessel 34. In some embodiments, a conditioning vessel may be utilized between the melting vessel and the fining vessel, where the molten glass from the primary melting vessel is cooled to a temperature below that of the molten glass in the melting vessel before being further heated to continue the melting process or entering the fining vessel.

[0024] Air bubbles may be removed from the molten glass 28 in the fining vessel 34 by various techniques. For example, the raw material 24 may contain polyvalent compounds (i.e., fining agents) such as tin oxide that undergo a chemical reduction reaction to release oxygen when heated. Other suitable fining agents include, without limitation, arsenic, antimony, iron, and cerium. The fining vessel 34 is heated to a temperature higher than the temperature of the melting bath, thereby heating the molten glass and fining agent. The oxygen produced by the temperature-induced chemical reduction of the fining agent may diffuse into or fuse with air bubbles that were generated in the molten glass during the melting process. The enlarged air bubbles may then rise to the free surface of the molten glass in the fining vessel and then be released from the fining vessel. The air bubbles may further induce mechanical mixing of the molten glass in the fining vessel.

[0025] The downstream glass manufacturing apparatus 30 may further include another conditioning vessel, such as a mixing vessel 36 for mixing the molten glass. The mixing vessel 36 may be located downstream of the fining vessel 34. The mixing vessel 36 may be used to provide a homogenous glass melt composition, thereby reducing streaks of chemical or thermal inhomogeneities that would otherwise be present in the fined molten glass exiting the fining vessel. As can be seen, the fining vessel 34 may be connected to the mixing vessel 36 by a second connecting conduit 38. In some cases, the molten glass 28 may be gravity fed from the fining vessel 34 to the mixing vessel 36 by the second connecting conduit 38. For example, gravity may cause the molten glass 28 to pass from the fining vessel 34 to the mixing vessel 36 through an internal passageway of the second connecting conduit 38. Although the mixing vessel 36 is shown downstream of the fining vessel 34, the mixing vessel 36 may also be located upstream of the fining vessel 34. In some embodiments, downstream glass manufacturing equipment 30 may include multiple mixing vessels, such as a mixing vessel upstream of fining vessel 34 and a mixing vessel downstream of fining vessel 34. These multiple mixing vessels may be of the same design or of different designs.

[0026] The downstream glass manufacturing apparatus 30 may further include another conditioning vessel, such as a feed vessel 40, which may be located downstream of the mixing vessel 36. The feed vessel 40 may condition the molten glass 28 to be fed to the downstream forming apparatus. For example, the feed vessel 40 may act as an accumulator and / or flow regulator to regulate and / or provide a consistent flow of the molten glass 28 to the forming body 42 via an outlet conduit 44. As can be seen, the mixing vessel 36 may be coupled to the feed vessel 40 by a third connecting conduit 46. In some cases, the molten glass 28 may be gravity fed from the mixing vessel 36 to the feed vessel 40 by the third connecting conduit 46. For example, gravity may cause the molten glass 28 to pass from the mixing vessel 36 to the feed vessel 40 through an internal passage of the third connecting conduit 46.

[0027] The downstream glass manufacturing apparatus 30 may further include a forming apparatus 48 including the forming body 42 and inlet conduit 50 described above. The outlet conduit 44 may be positioned to deliver the molten glass 28 from the feed vessel 40 to the inlet conduit 50 of the forming apparatus 48. For example, the outlet conduit 44 may be nested within the inlet conduit 50 and spaced from its inner surface, thereby providing a free surface of molten glass positioned between the outer surface of the outlet conduit 44 and the inner surface of the inlet conduit 50. The forming body 42 in a fusion downdraw glass manufacturing apparatus may include a trough 52 positioned on the top surface of the forming body 42 and a converging forming surface 54 that converges in the draw direction along a bottom edge 56 of the forming body 42. The molten glass delivered to the trough of the forming body through the feed vessel 40, the outlet conduit 44, and the inlet conduit 50 overflows the sidewall of the trough and descends along the converging forming surface 54 as a separate stream of molten glass. The separate streams of molten glass join below and along the bottom edge 56 to produce a single glass ribbon 58, which is drawn in a flow direction 60 from the bottom edge 56 by applying tension to the glass ribbon, such as by gravity, edge rolls 72 and pulling rolls 82, to control the dimensions of the glass ribbon as the glass cools and the viscosity of the glass increases. Thus, the glass ribbon 58 undergoes a viscoelastic transition and acquires mechanical properties that give the glass ribbon 58 stable dimensional characteristics. The glass ribbon 58 may be divided into individual glass sheets 62 at a glass dividing device 100 in the elastic region of the glass ribbon, in some embodiments. A robot 64 may then transfer the individual glass sheets 62 using grippers 65 to a transport system where the individual glass sheets may be further processed.

[0028] 2 shows a side cutaway view of an exemplary glass melting tank 14 according to embodiments disclosed herein. The glass melting tank 14 includes a tank 114 positioned above a floor 126, where a raw material feeder 20 delivers a predetermined amount of raw materials 24 to the tank 114 through a feed port 116, the combination of the raw material feeder 20 and the feed port 116 comprising a feeder. The glass melting tank 14 may also include a plurality of electrodes 102 and a plurality of combustion burners 104.

[0029] During operation, the multiple electrodes 102 and the multiple combustion burners 104 heat the vessel 114 such that the raw material 24 is melted into molten glass 28 to a predetermined level (L) within the vessel 114. As can be seen in FIG 2, the multiple combustion burners 104 are positioned above the predetermined level (L) and the multiple electrodes 102 are positioned below the predetermined level (L).

[0030] 3 and 4 respectively show cutaway top and end views of the exemplary glass melting tank 14 of FIG. 2. As can be seen from FIG. 3 and 4, each combustion burner 104 emits a flame 108 into the tank 114. In addition, as shown in FIG. 3, the feed port 116 is disposed in a first wall 120 of the tank 114, and the plurality of combustion burners 104 are disposed in second and third walls 122, 124 of the tank 114, each of which is generally parallel to one another and extends in a direction generally perpendicular to the first wall 120. The first, second and third walls 120, 122 and 124 are also generally perpendicular to the floor 126.

[0031] As shown in Figure 4, the glass melting tank 14 includes an electrode 106 extending from a floor 126, the electrode 106 being positioned below a predetermined level (L). As further shown in Figure 4, the combustion burner 104 emits a flame 108 in a direction generally parallel to the predetermined level (L).

[0032] 2-4 depict the glass melting tank 14 including an electrode 102 extending from the wall of the tank 114, an electrode 106 extending from the floor 126, and a combustion burner 104, embodiments disclosed herein can include glass melting tanks 14 that do not include one or more of these components. Collectively, one or more of these components comprise a heating mechanism.

[0033] In certain exemplary embodiments, electrode 102 and / or electrode 106 are made from at least one of tin oxide and molybdenum, hi certain exemplary embodiments, electrode 102 is made from tin oxide and electrode 106 is made from molybdenum.

[0034] Figure 5 shows a bottom cutaway view of the example glass melting tank 14 of Figures 2-4. As shown in Figure 5, the electrodes 106 extending from the floor 126 form a plurality of electrodes 106 extending along linear, generally parallel lengths of the glass melting tank 14.

[0035] FIGURE 6 illustrates a side cutaway view of a floor 126 of an exemplary glass melting tank 14 according to embodiments disclosed herein. As shown in FIGURE 6, the bed 126 includes multiple layers. Specifically, the bed 126 includes a first layer 150 made from a first refractory ceramic material and a second layer 152 made from a second refractory ceramic material. The bed 126 also includes a layer 154 made from an electrical resistivity enhancing material positioned between the first layer 150 and the second layer 152.

[0036] In certain exemplary embodiments, the first refractory ceramic material comprises zirconia, such as fused zirconia, including CZ-type fused zirconia, such as Scimos CZ, Scimos Z, Xilec 9, Xilec 5, or ER1195 available from St. Gobain, Monofrax ZHR or Mono Z available from Monofrax LLC, or ZBX9510 or ZBX9540 available from Asahi Ceramics.

[0037] In certain exemplary embodiments, the second refractory ceramic material comprises alumina, zircon, or alumina zirconia silica (AZS), such as A1148 (alumina) and ZS1300 (zircon) available from St. Gbain, Mono CS-3 or Mono CS-5 available from Monofrax LLC, or Supral S70, Supral AZ 50, or Supral AZ 70 available from RHI Magnesita.

[0038] In certain exemplary embodiments, the electrical resistivity enhancing material includes at least one material selected from Ta, Nb, Mo, W, V, or Cr, and / or an oxide thereof, including Ta2O5, Nb2O5, MoO3, WO3, V2O5, or CrO3. In certain exemplary embodiments, the electrical resistivity enhancing material includes Ta2O5.

[0039] In certain exemplary embodiments, the layer 154 made from an electrical resistivity enhancing material includes at least one of alumina, silica, or glass, such as an alumina silicate glass, including a boron-containing alumina silicate glass.

[0040] In certain exemplary embodiments, the layer 154 made from the electrical resistivity enhancing material has a thickness ranging from about 0.03 inches to about 6 inches (about 0.762 mm to about 15.2 cm), such as from about 0.1 inches to about 3 inches (about 2.54 mm to about 7.62 cm), even from about 0.5 inches to about 1 inch (about 1.27 cm to about 2.54 cm).

[0041] In certain exemplary embodiments, the electrical resistivity enhancing material comprises from about 0.1 to about 100 weight percent of the layer 154 made from the electrical resistivity enhancing material, such as from about 1 to about 80 weight percent, or even from about 5 to about 50 weight percent.

[0042] FIG. 7 illustrates a side cutaway view of the floor 126 of an exemplary glass melting tank 14 according to embodiments disclosed herein, and FIG. 8 illustrates a top cutaway view of a portion of the floor 126 of FIG. 7. As shown in FIGS. 7 and 8, the layer 154 made of electrical resistivity enhancing material includes a first region 154a and a second region 154b. The first region 154a includes a higher concentration of electrical resistivity enhancing material than the second region 154b. For example, prior to or during diffusion of the electrical resistivity enhancing material, the first region 154a may include at least about 1.1 times higher concentration of electrical resistivity enhancing material, such as at least about 1.5 times, even at least about 2 times, or even at least about 10 times, of the second region, which includes about 1.1 times to about 1000 times, even about 1.5 times to about 500 times, even about 2 times to about 200 times, even about 5 times to about 100 times higher concentration of electrical resistivity enhancing material than the second region.

[0043] 7 and 8 show alternating regular cross-sectional areas of the first and second regions 154a, 154b, embodiments disclosed herein may include other configurations of the first and second regions 154a, 154b, such as other polynomial cross-sections and / or shapes of the first and / or second regions 154a, 154b and / or shapes having circular or elliptical cross-sections, for example, spherical or tubular shapes of the first and / or second regions 154a, 154b, and / or configurations where at least one of the first regions 154a surrounds at least one of the second regions 154b and / or where at least one of the second regions 154b surrounds at least one of the first regions 154a.

[0044] For example, the first region 154a may include a higher concentration of at least one of Ta, Nb, Mo, W, V, or Cr, and / or Ta2O5, Nb2O5, MoO3, WO3, VO5, or CrO3 than the second region 154b, while the second region 154b may include a higher concentration of at least one of alumina, silica, or glass than the first region 154a.

[0045] 9 illustrates a side cutaway view of the floor 126 of an example glass melting tank 14 according to embodiments disclosed herein. The example glass melting tank 14 of FIG. 9 is similar to that of FIG. 6, except that a shielding layer 158 is positioned between the layer 154 made of the electrical resistivity enhancing material and the second layer 152. The shielding layer 158 can reduce or prevent diffusion of the electrical resistivity enhancing material into the second layer 152 and / or promote increased diffusion of the electrical resistivity enhancing material into the first layer 150.

[0046] In certain exemplary embodiments, the shielding layer 158 is made from a highly crystalline (at least 95% crystalline phase by mass), highly porous (at least 10% porosity by volume) material, which may include, for example, one or more solid paving layers, brick layers, or monolith powder layers. For example, the shielding layer 158 may be made from recombined fused mullite, alumina, or andalusite, such as Supral E 75, Supral K 99, Supral S 70, or Supral S 60, available from RHI Magnesita. In certain exemplary embodiments, the shielding layer 158 has a thickness ranging from about 0.5 inches to about 3 inches (about 1.27 cm to about 7.62 cm), such as from about 1 inch to about 2 inches (about 2.54 cm to about 5.08 cm).

[0047] Figure 10 illustrates a side cutaway view of floor 126 of an example glass melting tank 14 according to embodiments disclosed herein. The example glass melting tank 14 of Figure 10 is similar to that of Figure 6, except that a layer 154 made from an electrical resistivity enhancing material is positioned within first layer 150 such that a first portion 150a of first layer 150 is positioned above layer 154 made from electrical resistivity enhancing material and a second portion 150b of first layer 150 is positioned below layer 154 made from electrical resistivity enhancing material.

[0048] FIG 11 illustrates an end cutaway view of a floor area of ​​an exemplary glass melting tank 15 according to embodiments disclosed herein, and FIG 12 illustrates a top cutaway view of a portion of the floor 126 of FIG 11. As shown in FIGs 11 and 12, a layer 154 made from an electrical resistivity enhancing material surrounds the first layer 150. As further shown in FIG 11, the layer 154 made from an electrical resistivity enhancing material is embedded within the walls (e.g., second and third walls 122, 124) of the glass melting tank 14.

[0049] FIG 13 illustrates an end cutaway view of a bed 126 of an exemplary glass melting tank 14 according to embodiments disclosed herein, and FIG 14 illustrates a top cutaway view of a portion of the bed 126 of FIG 13. As shown in FIGs 13 and 14, a layer 154 made from an electrical resistivity enhancing material includes a first region 154a and a second region 154b, where the first region 154a extends along a central length of the bed 126 and the second region 154b extends along an opposing length of the bed 126 to the first region 154a. As with the bed 126 described and illustrated with respect to FIGs 7 and 8, the first region 154a includes a higher concentration of electrical resistivity enhancing material than the second region 154b.

[0050] During operation, a heating mechanism, for example comprising at least one of the electrodes 102 or 106 or the combustion burner 104, converts the raw material 24 provided to the glass melting tank 14 into molten glass 28. Such a heating mechanism not only serves to heat the raw material 24, but also heats the components of the glass melting tank 14, including the bed 126. As the bed 126 heats, the diffusivity of the electrical resistivity enhancing material of the layer 154 increases such that the electrical resistivity enhancing material gradually diffuses into the at least one layer (e.g., the first layer 150) made of the refractory ceramic material during operation of the glass melting tank 14. This in turn increases the electrical resistivity of the at least one layer (e.g., the first layer 150) made of the refractory ceramic material.

[0051] For example, during steady state operation of the glass melting tank 14, the temperature of the layer 154 made from the electrical resistivity enhancing material may range from about 1300° C. to about 1500° C., such as from about 1350° C. to about 1450° C. Such a temperature range may increase the diffusivity of the electrical resistivity enhancing material while still maintaining the mechanical integrity of the layer 154 as well as the mechanical integrity of the first layer 150 and the second layer 152.

[0052] The embodiments disclosed herein can enable, for example, at least about 5%, e.g., at least 10%, e.g., about 5% to about 25% greater electrical resistivity of the bed 126 (or a portion of the bed 126, such as the first layer 150) at a given temperature and production run compared to a melting tank 14 that does not include a layer 154 made of an electrical resistivity-enhancing material that is adapted to diffuse into at least one layer (e.g., the first layer 150) made of a refractory ceramic material during operation of the glass melting tank 14.

[0053] Such increased electrical resistivity, in turn, can enable a glass melting furnace 12 and / or glass melting tank 14 in which the occurrence of fire-through is mitigated or delayed, such as delayed by a period of at least about one year during production operations (thereby extending the useful life of the melting furnace 12 and / or melting tank 14), as compared to a melting tank 14 that does not include a layer 154 made of an electrical resistivity-enhancing material that is configured to diffuse into at least one layer (e.g., first layer 150) made of a refractory ceramic material during operation of the glass melting tank 14.

[0054] Additionally, given that fire-through often occurs near or below areas of highest current density, embodiments disclosed herein include those in which the layer 154 made from electrical resistivity enhancing material includes one or more first regions 154a including a higher concentration of electrical resistivity enhancing material than one or more second regions 154b (such as those shown in FIGS. 7 and 8 ), where the regions 154a including the higher concentration of electrical resistivity enhancing material are positioned near or below the areas of highest current density, such as near or below areas where the electrodes 102 and / or 106 face each other across opposite sides of the glass melting tank 14.

[0055] In certain exemplary embodiments, electrical resistivity enhancing materials such as those present in layer 154 may be encapsulated or covered within a material that can dissolve or disintegrate over time to further control the diffusion rate, such as within a predetermined range.

[0056] In certain exemplary embodiments, one or more layers (e.g., first layer 150) made from a refractory ceramic material may be pre-doped with an electrical resistivity enhancing material prior to in situ diffusion of the electrical resistivity enhancing material (e.g., from layer 154 to first layer 150) during operation of the glass melting tank 14. For example, one or more layers (e.g., first layer 150) made from a refractory ceramic material may be pre-doped with at least one material selected from Ta2O5, Nb2O5, MoO3, WO3, VO5, or CrO3.

[0057] Although the above-described embodiments have been described with reference to a fusion downdraw process, it should be understood that such embodiments are also applicable to other glass forming processes, such as slot-draw, float, updraw, and rolling processes.

[0058] Such processes can be used to manufacture glass articles, which can be used, for example, in electronic devices, as well as in other applications.

[0059] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present disclosure without departing from the spirit and scope of the disclosure, and therefore, the present disclosure is intended to cover such modifications and variations, provided they come within the scope of the appended claims and their equivalents.

[0060] Preferred embodiments of the present invention will be described below in detail.

[0061] EMBODIMENT 1 In the glass melting tank, A heating mechanism; a bed including at least one layer made of a refractory ceramic material and a layer made of an electrical resistivity enhancing material, the electrical resistivity enhancing material adapted to diffuse into the at least one layer made of the refractory ceramic material during operation of the glass melting tank; a glass melting tank comprising:

[0062] EMBODIMENT 2 2. The glass-melting tank of embodiment 1, wherein the at least one layer comprises a first layer made from a first refractory ceramic material and a second layer made from a second refractory ceramic material, and the layer made from an electrical resistivity-enhancing material is disposed between the first layer and the second layer.

[0063] EMBODIMENT 3 3. The glass melting tank of embodiment 2, wherein a shielding layer is disposed between the layer made of the electrical resistivity enhancing material and the second layer.

[0064] EMBODIMENT 4 3. The glass melting tank according to embodiment 2, wherein the first refractory ceramic material comprises zirconia and the second refractory ceramic material comprises alumina.

[0065] EMBODIMENT 5 2. The glass melting tank of embodiment 1, wherein the layer made of electrical resistivity enhancing material includes a first region and a second region, the first region including a higher concentration of electrical resistivity enhancing material than the second region.

[0066] EMBODIMENT 6 2. The glass melting tank of embodiment 1, wherein a layer made from the electrical resistivity enhancing material surrounds at least one layer made from the refractory ceramic material.

[0067] EMBODIMENT 7 2. The glass melting tank of embodiment 1, wherein the electrical resistivity enhancing material comprises about 0.1 to about 100 weight percent of the layer made from the electrical resistivity enhancing material.

[0068] EMBODIMENT 8 2. The glass melting tank of embodiment 1, wherein the electrical resistivity enhancing material comprises at least one material selected from Ta, Nb, Mo, W, V, Cr, Ta2O5, Nb2O5, MoO3, WO3, V2O5, or CrO3.

[0069] EMBODIMENT 9 9. The glass melting tank of embodiment 8, wherein the electrical resistivity enhancing material comprises Ta2O5.

[0070] EMBODIMENT 10 2. The glass melting tank of embodiment 1, wherein the layer made of an electrical resistivity enhancing material comprises at least one of alumina, silica, or glass.

[0071] EMBODIMENT 11 1. A method of operating a glass melting tank, comprising the steps of: The glass melting tank comprises: A floor comprising at least one layer made of a refractory ceramic material; and a layer made of an electrical resistivity enhancing material; Including, The method comprises: Supplying raw materials to the melting tank; converting the raw materials fed into the melting tank into molten glass; and diffusing said electrical resistivity enhancing material into at least one layer made of said refractory ceramic material during operation of said glass melting tank; A method comprising:

[0072] EMBODIMENT 12 12. The method of claim 11, wherein the at least one layer comprises a first layer made from a first refractory ceramic material and a second layer made from a second refractory ceramic material, and the layer made from an electrical resistivity enhancing material is disposed between the first layer and the second layer.

[0073] EMBODIMENT 13 13. The method of claim 12, wherein a shielding layer is disposed between the layer made of electrical resistivity enhancing material and the second layer.

[0074] EMBODIMENT 14 13. The method of embodiment 12, wherein the first refractory ceramic material comprises zirconia and the second refractory ceramic material comprises alumina.

[0075] EMBODIMENT 15 12. The method of claim 11, wherein the layer made of the electrical resistivity enhancing material comprises a first region and a second region, the first region comprising a higher concentration of the electrical resistivity enhancing material than the second region.

[0076] EMBODIMENT 16 12. The method of claim 11, wherein the layer made from the electrical resistivity enhancing material surrounds at least one layer made from the refractory ceramic material.

[0077] EMBODIMENT 17 12. The method of claim 11, wherein the electrical resistivity enhancing material comprises about 0.1 to about 100 weight percent of the layer made from the electrical resistivity enhancing material.

[0078] EMBODIMENT 18 12. The method of claim 11, wherein the electrical resistivity enhancing material comprises at least one material selected from Ta, Nb, Mo, W, V, Cr, Ta2O5, Nb2O5, MoO3, WO3, V2O5, or CrO3.

[0079] EMBODIMENT 19 20. The method of embodiment 18, wherein the electrical resistivity enhancing material comprises Ta2O5.

[0080] EMBODIMENT 20 12. The method of claim 11, wherein the layer made of electrical resistivity enhancing material comprises at least one of alumina, silica, or glass. [Explanation of symbols]

[0081] 10. Glass manufacturing equipment 12 Glass melting furnace 14 Melting tank 16 Upstream glass manufacturing equipment 18 Storage Containers 20 Raw material supply equipment 22 Motor 24 Raw Materials 28 Molten Glass 30 Downstream glass manufacturing equipment 32 First connecting conduit 34 Clarifying tank 36 Mixing tank 38 Second connecting conduit 40 Supply tank 42 Molded body 44 Outlet conduit 46 Third connecting conduit 48 Molding equipment 50 Inlet conduit 52 Gutter 54 Convergent forming surface 56 Lower edge 58 Glass Ribbon 62 Glass Sheet 64 Robot 65 Grasping instruments 72 Edge Roll 82 Traction Roll 102, 106 electrode 104 Combustion burner 108 Flame 114 tanks 116 Supply Port 120 The First Wall 122 The Second Wall 124 The Third Wall 126 Beds 150 First Layer 150a First Part 150b Second Part 152 Second Layer 154 Layers made from materials with enhanced electrical resistivity 154a First Area 154b Second Area

Claims

1. In the glass melting tank, A heating mechanism; a bed including at least one layer made of a refractory ceramic material and a layer made of an electrical resistivity enhancing material, the electrical resistivity enhancing material adapted to diffuse into the at least one layer made of the refractory ceramic material during operation of the glass melting tank; a glass melting tank comprising:

2. 2. The glass melting tank of claim 1, wherein the at least one layer includes a first layer made from a first refractory ceramic material and a second layer made from a second refractory ceramic material, the layer made from the electrical resistivity enhancing material being disposed between the first layer and the second layer.

3. The glass melting tank of claim 2 , wherein a shielding layer is disposed between the layer made of the electrical resistivity enhancing material and the second layer.

4. The glass melting tank of claim 2 , wherein the first refractory ceramic material comprises zirconia and the second refractory ceramic material comprises alumina.

5. 2. The glass melting tank of claim 1, wherein the layer made of the electrical resistivity enhancing material includes a first region and a second region, the first region including a higher concentration of the electrical resistivity enhancing material than the second region.

6. The glass melting tank of claim 1 , wherein the layer made of the electrical resistivity enhancing material surrounds at least one layer made of the refractory ceramic material.

7. The glass melting tank of claim 1 , wherein the electrical resistivity enhancing material comprises about 0.1 to about 100 weight percent of the layer made from the electrical resistivity enhancing material.

8. The electrical resistivity enhancing material is Ta, Nb, Mo, W, V, Cr, Ta ２ O ５ , Nb ２ O ５ , MoO ３ , W.O. ３ , V ２ O ５ , or CrO ３ The glass melting tank of claim 1 , comprising at least one material selected from the group consisting of:

9. 1. A method of operating a glass melting tank, comprising the steps of: The glass melting tank comprises: A floor comprising at least one layer made of a refractory ceramic material; and a layer made of an electrical resistivity enhancing material; Including, The method comprises: Supplying raw materials to the melting tank; converting the raw materials fed into the melting tank into molten glass; and diffusing said electrical resistivity enhancing material into at least one layer made of said refractory ceramic material during operation of said glass melting tank; A method comprising:

10. 10. The method of claim 9, wherein the at least one layer includes a first layer made from a first refractory ceramic material and a second layer made from a second refractory ceramic material, the layer made from the electrical resistivity enhancing material being disposed between the first layer and the second layer.

11. The method of claim 10 , wherein a shielding layer is disposed between the layer made of the electrical resistivity enhancing material and the second layer.

12. The method of claim 10 , wherein the first refractory ceramic material comprises zirconia and the second refractory ceramic material comprises alumina.

13. 10. The method of claim 9, wherein the layer made of electrical resistivity enhancing material includes a first region and a second region, the first region including a higher concentration of electrical resistivity enhancing material than the second region.

14. The method of claim 9 , wherein a layer made from the electrical resistivity enhancing material surrounds at least one layer made from the refractory ceramic material.

15. The method of claim 9 , wherein the electrical resistivity enhancing material comprises about 0.1 to about 100 weight percent of the layer made from the electrical resistivity enhancing material.

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