Flange design for direct heating of platinum delivery system

Abstract

A glass transfer system for heating molten glass is provided. The glass transfer system comprises a glass transfer tube that is configured to allow molten glass to flow within an internal volume of the glass transfer tube. The glass transfer system also comprises a support assembly having an inner surface defining an internal opening therein configured to receive the glass transfer tube. The internal opening defines a height and a width, the height is greater than the width, and the support assembly is configured to receive the glass transfer tube within the internal opening.

Description

SP24-215FLANGE DESIGN FOR DIRECT HEATING OF PLATINUM DELIVERY SYSTEMCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63 / 683408 filed on August 15, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.FIELD

[0002] Embodiments relate generally to flanges assemblies for heating molten glass within glass transfer tubes and support assemblies providing improved support for glass transfer tubes.BACKGROUND

[0003] In glass transfer systems, molten glass is channeled through a delivery system comprising sets of tubing. This tubing often includes precious metals such as platinum or platinum -rhodium alloys. The tubing is capable of receiving an electrical current, and this electrical current is configured to heat the tubing and the molten glass within the tubing.

[0004] In existing flange designs, electrical current reaches the tubing at different electrical current densities around the perimeter of the tubing, and, thus, existing flange designs often fail to adequately distribute the electrical current around the perimeter of the tubing with high electrical current densities at certain areas and low electrical current densities at other areas. Where electrical current densities are significantly different in different locations, locations in the tubing or the flange assemblies may be hotter in temperature or colder in temperature compared to other locations. The differences in temperature may lead to thermal inhomogeneities in the glass itself that can lead to quality issues such as devitrification, streak defects, unmelted batch inclusions, etc. Additionally, where electrical current densities are significantly different in different locations, material within the tubing and / or the flange assemblies may be degraded at a faster rate, leading to a reduction in the life of the tubing and / or the flange assemblies.

[0005] To form glass, molten glass is typically transferred from one location to another within a larger assembly so that the molten glass may be refined. For example, glass is often melted, fined, and stirred. In transferring the molten glass, the assembly for transferring the molten glass is exposed to very high temperatures. Additionally, molten glass is sometimes transferred using tubes with an inner volume defining an oblong or oval shape, with the width forming the major axis of the shape and with the height forming the minor axis. The inner volume defines a width-to-height ratio, with this ratio being the width of the inner volumeSP24-215 divided by the height. In many existing assemblies, the inner volume defines a width-to-height ratio of above about 1.5. Where these configurations are used, glass transfer tubes often tend to deform in shape at certain areas such as the upper portions of the glass transfer tubes.BRIEF SUMMARY

[0006] Various embodiments described herein provide designs for flange assemblies. The flange assemblies may define central openings therein that are configured to receive glass transfer tubes such as stir-chamber-to-bowl connections in glass transfer systems. The flange assemblies may be connected to an electrical power source so that electrical current is conducted through the flange assemblies, and to the glass transfer tube so that the glass transfer tube is heated and so that this heat is transferred at least partially to the molten glass.

[0007] These flange assemblies may be provided with improved electrical current uniformity throughout the flange assemblies while also allowing for a reduction in the amount of material that is used in flange assemblies. Flange assemblies may be provided with cut-outs and particular geometries that may provide these benefits. For example, the flange assemblies may include additional openings, different thicknesses at segments therein, curved segments to increase the electrical current path in certain segments, and different fillet sizes. However, other changes are also contemplated. Flange assemblies may also be used with smaller power supplies (e.g., low frequency power supplies), and this may also lead to further improvements in electrical current distribution. Flange assemblies may also be made in a more cost effective manner as transformers with lower power capability may be mounted directly to the flanges assemblies of various embodiments described herein.

[0008] Support assemblies for glass transfer tubes are also contemplated in various embodiments herein. These support assemblies may include castable material, refractory material, and other materials. The support assemblies include internal surfaces defining internal openings therein. The internal openings possess a vertical geometry where the width of the internal openings is less than the height of the internal openings. Glass transfer tubes comprising platinum may be positioned in the internal openings of support assemblies. Having internal openings with a width that is less than the height may enable the shape of the glass transfer tubes to be maintained during heating to an operating temperature and when the glass transfer tubes are experiencing little internal pressure. In some embodiments, the shape of the glass transfer tubes may be maintained without using any additional internal or external supports, with the natural stability of the arch providing support to prevent sagging of the glassSP24-215 transfer tubes during periods when the glass transfer tubes are experiencing little internal pressure (e.g., when molten glass is not yet flowing through the glass transfer tubes) and when the glass transfer tubes are heated to higher temperatures. Where sagging occurs at the top of glass transfer tubes, this may lead to failure for thermocouples positioned in the glass transfer tube and may also lead to collapse of the glass transfer tube.

[0009] With the natural stability of arch providing improved support, support assemblies may be made with significantly less metal materials. In some embodiments, support assemblies may be made with at least about 20% less metal than other support assemblies using a horizontal geometry. This may enable support assemblies to be made in a more cost-effective manner.

[0010] Having internal openings with a width that is less than the height provides a support solution that does not introduce potential high stress and high strain to the body of glass transfer tubes. A width-to-height ratio for internal openings may be optimized to provide a high amount of support for glass transfer tubes, and the width-to-height ratio (width divided by the height) may be less than 1, between about 0.5 and about 0.9, between about 0.6 and about 0.8, between about 0.65 and about 0.75, or about 0.7.

[0011] As glass transfer tubes are used at higher temperatures, support of the material within the glass transfer tubes (e.g., platinum) becomes more critical. Even when the same amount of stress is applied, the creep rate for glass transfer tubes increases exponentially as the temperature is increased. Providing support for the glass transfer tubes is important to mitigate the risk of glass leaks from the glass transfer tubes. A castable material may be provided adjacent to the glass transfer tube, with the castable material providing close support to the glass transfer tube and reducing the risk of leaks from the glass transfer tube.

[0012] In an example embodiment, a glass transfer system for heating molten glass is provided. The glass transfer system includes a glass transfer tube configured to allow molten glass to flow within an internal volume of the glass transfer tube . The glass transfer system also includes a support assembly having an inner surface defining an internal opening therein configured to receive the glass transfer tube. The internal opening defines a height and a width, the height is greater than the width, and the support assembly is configured to receive the glass transfer tube within the internal opening.

[0013] In some embodiments, a width-to-height ratio may be equal to the width divided by the height, and the width-to-height ratio may be between about 0.5 and about 0.9. Additionally,SP24-215 in some embodiments, the width-to-height ratio may be between about 0.6 and about 0.8. In some embodiments, the width-to-height ratio may be between about 0.65 and about 0.75.

[0014] In some embodiments, the glass transfer tube may include platinum.

[0015] In some embodiments, the support assembly may include a refractory cradle positioned outwardly relative to the internal opening of the support assembly, and the refractory cradle may include a refractory material. Additionally, in some embodiments, the support assembly may comprise a castable material positioned outwardly relative to the internal opening of the support assembly, and the castable material may be positioned inwardly relative to the refractory cradle.

[0016] In some embodiments, the glass transfer system also includes a stir chamber and a bowl. The glass transfer tube may extend between the stir chamber and the bowl.

[0017] In some embodiments, the glass transfer tube may define an inlet and an outlet, the glass transfer system may be configured to reach an inlet temperature at the inlet of the glass transfer tube, and the inlet temperature may be at least about 1300 degrees Celsius. In some embodiments, the inlet temperature may be between about 1300 degrees Celsius and about 1570 degrees Celsius.

[0018] In some embodiments, the internal surface of the support assembly may define a top rounded portion, a bottom rounded portion, and two planar side surfaces. Additionally, in some embodiments, a radius of curvature at the top rounded portion and a radius of curvature at the bottom rounded portion may be constant.

[0019] In some embodiments, the support assembly may also include a support tab. A first end of the support tab may be attached to the glass transfer tube, and the support tab may be configured to apply a force to the glass transfer tube to reduce elastic buckling, plastic buckling, creep buckling, or creep sag deformation at the glass transfer tube.

[0020] In another example embodiment, a support assembly for a glass transfer tube is provided. The support assembly comprises at least one support section. The support section(s) comprises a refractory cradle comprising a refractory material, and the support section(s) includes an internal surface defining an internal opening therein. The internal opening is configured to receive the glass transfer tube, the internal opening has a height and a width, and the height is greater than the width. The support assembly is configured to receive the glass transfer tube within the internal opening so that the support assembly contacts the glass transfer tube.SP24-215

[0021] In some embodiments, a width-to-height ratio is equal to the width divided by the height, and the width-to-height ratio may be between about 0.5 and about 0.9. The width-to- height ratio may be between about 0.6 and about 0.8 or between about 0.65 and about 0.75.

[0022] In some embodiments, the support section(s) may comprise a castable material positioned outwardly relative to the internal opening, and the castable material may be positioned inwardly relative to the refractory cradle. In some embodiments, the castable material may be positioned adjacent to the internal opening such that the castable material forms the internal surface.

[0023] In some embodiments, the internal surface may define a top rounded portion, a bottom rounded portion, and two planar side surfaces. Additionally, in some embodiments, a radius of curvature at the top rounded portion and the bottom rounded portion may be constant.

[0024] In some embodiments, the support assembly may also include a support tab, a first end of the support tab may be attached to the glass transfer tube, and the support tab may be configured to apply a force to the glass transfer tube to reduce buckling at the glass transfer tube.

[0025] In some embodiments, the internal opening may define a top rounded portion, a bottom rounded portion, and two planar side surfaces, and the support tab may be positioned proximate to the top rounded portion or one of the two planar side surfaces.

[0026] In another example embodiment, a method of using a glass transfer system for heating molten glass is provided. The method comprises positioning a glass transfer tube relative to a support assembly. The support assembly comprises an internal surface defining an internal opening therein, and the glass transfer tube is positioned within the internal opening so that the glass transfer tube is in contact with the support assembly. The internal opening defines a height and a width, and the height is greater than the width. The method also includes causing molten glass to flow through an internal volume of the glass transfer tube. In some embodiments, a width-to-height ratio is equal to the width divided by the height, and the width- to-height ratio is between about 0.65 and about 0.75.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:SP24-215

[0028] FIG. 1A is a schematic view illustrating a glass transfer tube positioned relative to other components of an exemplary glass manufacturing system, in accordance with some embodiments discussed herein;

[0029] FIG. IB is an enhanced view illustrating an example flange assembly of a glass transfer system, in accordance with some embodiments discussed herein;

[0030] FIG. 2 is a front view illustrating an example flange assembly, in accordance with some embodiments discussed herein;

[0031] FIG. 3 is a front view illustrating the electrical current density at various locations on one side of a flange assembly, in accordance with some embodiments discussed herein;

[0032] FIG. 4 is a front view illustrating another example flange assembly and the electrical current density at various locations on the flange assembly, in accordance with some embodiments discussed herein;

[0033] FIG. 5 is a graph illustrating how a top rib thickness impacts the electrical current properties within a flange assembly, in accordance with some embodiments discussed herein;

[0034] FIG. 6 is a line graph illustrating a normalized electrical current density at various points around a tube for different flange assembly designs, in accordance with some embodiments discussed herein;

[0035] FIGS. 7-8 are front views illustrating example flange assemblies, in accordance with some embodiments discussed herein;

[0036] FIG. 9 is a front view illustrating one side of another example flange assembly and electrical current density at various locations on that side of the flange assembly, in accordance with some embodiments discussed herein;

[0037] FIG. 10 is a front view illustrating an example side of another example flange assembly and various dimensions for the flange assembly, in accordance with some embodiments discussed herein;

[0038] FIG. 11 illustrating another two sides from different flange assemblies and the electrical current density at various locations on the sides is a front view illustrating one side of one example flange assembly positioned adjacent to one side of another example flange assembly so that impact of the design for the two flange assemblies on the electrical current density may be seen, in accordance with some embodiments discussed herein;

[0039] FIG. 12 is a front view illustrating one side of one example flange assembly positioned adjacent to one side of another example flange assembly so that impact of the designSP24-215 for the two flange assemblies on the electrical current density may be seen, in accordance with some embodiments discussed herein;

[0040] FIG. 13 is a graph illustrating how different sizes for a fillet radius of a fillet impacts electrical current properties within a flange assembly, in accordance with some embodiments discussed herein;

[0041] FIG. 14 is a line graph illustrating the normalized electrical current density at various points around a tube for different flange assembly designs, in accordance with some embodiments discussed herein;

[0042] FIG. 15 is a front view illustrating a first side 1526A of one example flange assembly positioned adjacent to a second side 1526B of another example flange assembly so that differences in the design for the two flange assemblies may be seen, in accordance with some embodiments discussed herein;

[0043] FIG. 16A is a schematic view illustrating an example support assembly with an internal opening having a width that is greater than the height, in accordance with some embodiments discussed herein;

[0044] FIG. 16B is an enhanced view of the support assembly of FIG. 16A where an example support tab may be seen in greater detail, in accordance with some embodiments discussed herein;

[0045] FIG. 17 is a schematic view illustrating an example support assembly with an internal opening having a width that is less than its height, in accordance with some embodiments discussed herein;

[0046] FIGS. 18A-18C and FIGS. 19A-19C are schematic views illustrating deformation within a glass transfer tube comprising platinum when different internal opening geometries are used, in accordance with some embodiments discussed herein; and

[0047] FIG. 20 is a flow chart illustrating an example method for using a flange assembly and a support assembly, in accordance with some embodiments discussed herein.DETAILED DESCRIPTION

[0048] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments are shown. Other than the reference numbers set forth in FIGS. 1A and 20, like reference numerals generally refer to like elements throughout. For example, reference numbers 118, 218, 318, 418, etc. each refer to inner structures. Additionally, any connections or attachments may be direct or indirect connections or attachments unless specifically noted otherwise. As used herein, the termsSP24-215“central opening,” “middle opening,” and “internal opening” are intended to refer to different openings.

[0049] FIG. 1A is a schematic view illustrating a molten glass transfer assembly 115 in the positioned relative to other components of an exemplary glass manufacturing system 111. The glass manufacturing system 111 may use a fusion process to make a glass substrate 131. As shown in FIG. 1A, the glass manufacturing system 111 includes a melting vessel 105, a fining vessel 109, a stir chamber 133 (e.g., a mixing vessel), a delivery vessel 117, a glass forming apparatus 125A, and a pull roll assembly 129 (e.g., a draw machine). The melting vessel 105 is where the glass batch materials are introduced as shown by arrow 101 and melted to form molten glass 103. The temperature of the melting vessel (Tm) may vary based on the specific glass composition but may range from between about 1500 degrees Celsius and about 1650 degrees Celsius. For display glasses for use in liquid-crystal displays (LCDs), melting temperatures may exceed about 1500 degrees Celsius, about 1550 degrees Celsius and for some glasses, may even exceed about 1650 degrees Celsius. A cooling refractory tube 107 may optionally be present connecting the melting vessel 105 with the fining vessel 109. This cooling refractory tube 107 may have a temperature (Tc) between about 0 degrees Celsius and about 15 degrees Celsius cooler than the temperature of the melting vessel 105. The fining vessel 109 (e.g., a finer tube) has a high temperature processing area that receives the molten glass 103 from the melting vessel 105 and in which bubbles are removed from the molten glass 103. The temperature of the fining vessel 109 (Tf) is generally equal to or higher than that of the melting vessel 105 (Tm) in order to lower viscosity and encourage gas removal from the molten glass. In some embodiments, the fining vessel temperature is between about 1600 degrees Celsius and about 1720 degrees Celsius, and in some embodiments exceeds the temperature of the melting vessel by about 20 degrees Celsius to about 70 degrees Celsius, or more.

[0050] The fining vessel 109 is connected to the stir chamber 133 by a glass transfer assembly 113 in the form of finer to stir chamber (FSC). The glass transfer assembly 113 includes a glass transfer tube, with the glass transfer tube defining a hollow shape. Examples of molten glass transfer assemblies are described in greater detail herein. The hollow shape of the glass transfer tube may allow molten glass to flow within an internal volume of the glass transfer tube.

[0051] Within the glass transfer tube of the glass transfer assembly 113, the glass temperature is continually and steadily decreased from the fining vessel temperature (Tr) to theSP24-215 stir chamber temperature (Ts), which typically represents a temperature decrease of between about 150 degrees Celsius and about 300 degrees Celsius. Thus, the stir chamber 133 may generally operate at an operating temperature of between about 1300 degrees Celsius and about 1570 degrees Celsius in some embodiments, but other operating temperatures may be used for the stir chamber 133 in other embodiments.

[0052] The stir chamber 133 is connected to the delivery vessel 117 by another glass transfer assembly 115 in the form of a stir chamber to bowl connecting tube. The stir chamber 133 is responsible for stirring and homogenizing the glass melt and removing concentration differences within the glass that may cause defects. The glass transfer assembly 115 may include an area 115C proximate to the top of the glass transfer tube and proximate to the inlet 115A. This area 115C may be the area that is subject to the highest amounts of deflection within the glass transfer assembly 115, and this area 115C may be the area that is subject to the highest stresses within the glass transfer assembly 115. Where glass transfer assemblies are utilized with a horizontal geometry and with a width-to-height ratio of above 1, the maximum deflection amounts at the area 115C may reach up to about 17.526 millimeters (0.69 inches) and the stress at the area may reach up to about 2.4 MPa.

[0053] The delivery vessel 117 delivers the molten glass 103 through a downcomer 119 to an inlet 121 and into the glass forming apparatus 125A. The glass forming apparatus 125A includes an inlet 125B that receives the molten glass which flows into a trough 123 and then overflows and runs down a first side 125D and a second side (not shown) opposite the first side 125D before fusing together at what is known as a root 125C. The root 125C is where the first side 125D and the second side come together and where the two overflow walls of molten glass 127 rejoin (e.g., refuse) before being drawn downward between two rolls in the pull roll assembly 129 to form the glass substrate 131. The glass substrate 131 may eventually form one or more glass products.

[0054] FIG. IB is an enhanced view illustrating a flange assembly 112. The flange assembly 112 includes an inner structure 118. The inner structure 118 includes a first portion 118A and the second portion 118B. Both portions 118A, 118B may both comprise platinum, and the compositions of these portions 118A, 118B may be different in some embodiments. However, other metals or metal alloys may be used in place of platinum in other embodiments. The second portion 118B is positioned inwardly relative to the first portion 118A. While a first portion 118A and a second portion 118B are illustrated in the embodiment of FIG. IB, additional portions may be used in other embodiments, and each internal structure may have aSP24-215 different composition. The portions 118A, 118B may be attached together using welding or another attachment approach.

[0055] A central opening 120 is defined within the inner structure 118 where the glass transfer tube 114 may be received. Like the internal openings defined by support assemblies described herein, the central opening 120 may define a width-to-height ratio that is less than 1 such that the central opening 120 defines an oblong shape. This width-to-height ratio is the width of the central opening 120 divided by the height of the central opening 120. In some embodiments, the width-to-height ratio may be between about 0.5 and about 0.9, between about 0.6 and about 0.8, or between about 0.65 and about 0.75. In the illustrated embodiment, the width-to-height ratio is about 0.7. The flange assembly 112 may be connected to an electrical power source, and electrical current may be conducted through the arms of the flange assembly 112 to the inner structure 118 and to the glass transfer tube 114. This electrical current may generate heat that is transferred to the molten glass within the glass transfer tube 114.

[0056] The glass transfer tube 114 may serve as a stir-chamber-to-bowl (SCB) connection, with the glass transfer tube 114 extending from a stir chamber to a bowl. The bowl may be configured to interface at its bottom with a downcomer 119 (see FIG. 1A). The downcomer 119 (see FIG. 1 A) may be configured to deposit molten glass into a receiving passage of a glass forming system (e.g., an inlet pipe of a fusion forming assembly).

[0057] Flange assemblies like flange assembly 112 are positioned around the glass transfer tube 114 and may be welded or otherwise attached to the glass transfer tube 114. Flange assembly 112 has a rough gullwing-type shape. While the flange assembly 112 is used with a glass transfer tube 114 that acts as an SCB connection, flange assemblies may be used with glass transfer tubes used for other purposes. For example, flange assemblies may be incorporated at other locations in a glass formation system or with other transfer tubes where some other fluid material is transferred.

[0058] FIG. 2 is a front view illustrating an example flange assembly 212. The inner structure 218 includes a first portion 218A and a second portion 218B . The first portion 218A and the second portion 218B may both comprise platinum, but the compositions of the first portion 218A and the second portion 218B may be different in some embodiments. For example, other metals or metal alloys may be used in place of platinum in some embodiments. The second portion 218B is positioned inwardly relative to the first portion 218A. While a first portion 218 A and a second portion 218B are illustrated in the embodiment of FIG. 2, additional portions may be used in other embodiments, and each portion may have a differentSP24-215 composition. For example, four or more portions may be used in some embodiments. The portions 218A, 218B may be attached together using welding or another attachment approach. For example, portions 218A, 218B and other portions that form the inner structures described herein may be welded together and flattened during fabrication to form a singular continuous ring structure.

[0059] A central opening 220 is positioned within the inner structure 218 within the second portion 218B, and a glass transfer tube may be received within the central opening 220 so that the glass transfer tube comes in contact with the second portion 218B. The central opening 220 has a shape similar to the central opening 120 of FIG. 1C, and the central opening 220 may be configured to receive a glass transfer tube with a similar cross-sectional shape. However, the central opening 220 may possess another shape (e.g., a circular shape, a shape with a width greater than the height, etc.) in other embodiments.

[0060] The flange assembly 212 also includes an outer structure attached to the inner structure 218. The outer structure in flange assembly 212 and in other flange assemblies described herein may comprise a material other than platinum. In some embodiments, the outer structure in flange assembly 212 and in other flange assemblies described herein may comprise nickel. Further information regarding nickel-containing flange designs may be found in U.S. Pat. No. 8,796,579, entitled “Nickel-containing flanges for use in direct resistance heating of platinum-containing vessels,” which is incorporated by reference herein for all purposes.

[0061] The outer structure includes a central flange element 230, a first arm 228A, and a second arm 228B. In some embodiments, the outer structure may be of a singular design, with the different portions of the outer structure being integrally attached together. However, in other embodiments, the different portions of the outer structure (e.g., central flange element 230, a first arm 228A, a second arm 228B, etc.) may be attached together through welds or other attachment approaches.

[0062] The arms 228A, 228B extend from the central flange element 230. The central flange element 230 may be the part of the outer structure that is directly attached to the inner structure 218, and the central flange element 230 generally defines a shape similar to the shape of the central opening 220. The central flange element 230 includes an upper portion 231, a bottom portion 232, and two side portions 234A, 234B.

[0063] The arms 228A, 228B may also be connected to electrical power source(s) 255. The electrical power source(s) 255 may generate an electrical current that is conducted through the arms 228A, 228B, through the central flange element 230, through the inner structure 218,SP24-215 and through a glass transfer tube positioned within the central opening 220 so that molten glass therein may be heated. While two arms 228A, 228B are included within the outer structure in the illustrated embodiment a greater or lesser number of arms may be included in other embodiments. The electrical power source(s) 255 may be connected to the arms 228A, 228B via electric cables (e.g., buses) that interface with electrode extensions, and other flange assemblies described herein may be connected similarly.

[0064] The first arm 228A includes a first segment 236A and a second segment 238A connected to the central flange element 230. The first segment 236A and the second segment 238A have about the same thickness, but the thicknesses of the two segments 236A, 238A may be different in other embodiments. The first segment 236A and the second segment 238A are both straight, but the segments 236A, 238A may possess a different shape such as a curved shape in other embodiments. The first segment 236A and the second segment 238A join at a third segment 229A that is connected to the electrical power source 255. The first segment 236A, the second segment 238A, and the side portion 234A of the central flange element 230 surround the opening 240A. The opening 240A may define a generally triangular shape, but the comers of this shape may be rounded. The third segment 229A of the first arm 228A transitions so that the third segment 229A extends vertically as it approaches the electrical power source 255, and fillets 242A, 244A are provided at this transition to provide increased structural support at these areas.

[0065] The second arm 228B is generally symmetrical to the first arm 228A. A midline 224 bisects the flange assembly 212, and the midline 224 separates the first side 226A and the second side 226B. The flange assembly 212 may be symmetrical about the midline 224, and other flange assemblies described herein may similarly be symmetrical about their midlines. By making the flange assemblies symmetrical, the electrical current flow uniformity within the flange assembly 212 and within the inner structure 218 may be maximized. However, in other embodiments, flange assemblies may be made asymmetrical.

[0066] The second arm 228B includes a first segment 236B and a second segment 238B connected to the central flange element 230. The first segment 236B and the second segment 238B have about the same thickness, but the thicknesses of the two segments 236B, 238B may be different in other embodiments. The first segment 236B and the second segment 238B are both straight, but the segments 236B, 238B may possess a different shape such as a curved shape in other embodiments. The first segment 236B and the second segment 238B join at a third segment 229B that is connected to the electrical power source 255. The first segmentSP24-215236B, the second segment 238B, and the side portion 234B of the central flange element 230 surround the opening 240B. The opening 240B may define a generally triangular shape, but the corners of this shape may be rounded. The third segment 229B of the second arm 228B transitions so that it extends vertically as it approaches the electrical power source 255, and fillets 242B, 244B are provided at this transition to provide increased structural support at these areas. The fillets 242A, 242B are symmetrical to each other and possess a similar curvature, and the fillets 244A, 244B are symmetrical to each other and possess a similar curvature.

[0067] The openings 240A, 240B and other similar openings described herein may enable minimization of usage of precious metals. The openings 240A, 240B and other similar openings described herein may also provide improved electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 236A, 238A, 236B, 238B.

[0068] FIG. 3 is a front view illustrating the electrical current density at various locations on one side of a flange assembly. The side 326B that is illustrated in FIG. 3 is similar to the second side 226B of FIG. 2. FIG. 3 illustrates that electrical current may reach the inner structure 318 in different electrical current paths.

[0069] A single inner structure 318 is illustrated, but the inner structure 318 may comprise different sections in some embodiments. The inner structure 318 may comprise platinum. However, other metals or metal alloys may be used in place of platinum in other embodiments. A central opening 320 is positioned within the inner structure 318, and a glass transfer tube may be received within the central opening 320 so that the glass transfer tube comes in contact with the inner structure 318. The central opening 320 has a shape similar to the central opening 120 of FIG. 1C, and the central opening 320 may be configured to receive a glass transfer tube with a similar cross-sectional shape. However, the central opening 320 may possess another shape (e.g., a circular shape, a shape with a width greater than the height, etc.) in other embodiments.

[0070] The flange assembly that is partially illustrated in FIG. 3 also includes an outer structure attached to the inner structure 318. The outer structure may comprise nickel in some embodiments, but other materials may be used. The outer structure includes a central flange element 330, a first arm (not shown), and a second arm 328B. The arms extend from the central flange element 330. The central flange element 330 may be the part of the outer structure that is directly attached to the inner structure 318, and the central flange element 330 generally defines a shape similar to the shape of the central opening. The central flange element 330SP24-215 includes an upper portion 331, a bottom portion 332, a left-side portion (not shown), and a right-side portion 334B.

[0071] The arm 328B may also be connected to an electrical power source. The electrical power source may generate an electrical current that is conducted through the arm 328B, through the central flange element 330, through the inner structure 318, and through a glass transfer tube positioned within the central opening 320 so that molten glass therein may be heated.

[0072] The arm 328B is generally similar to the second arm 228B of FIG. 2. The arm 328B includes a first segment 336B and a second segment 338B connected to the central flange element 330. The first segment 336B and the second segment 338B have about the same thickness, but the thicknesses of the two segments 336B, 338B may be different in other embodiments. The first segment 336B and the second segment 338B are both straight, but the segments 336B, 338B may possess a different shape such as a curved shape in other embodiments. The first segment 336B and the second segment 338B join at a third segment 329B that is connected to an electrical power source. The first segment 336B, the second segment 338B, and the central flange element 330 surround an opening 340B. More specifically, the first segment 336B, the second segment 338B, and the right-side portion 334B of the central flange element 330 surround the opening 340B. The opening 340B may define a generally triangular shape, but the comers of this shape may be rounded. The third segment 329B of the arm 328B transitions so that the third segment 329B extends to a vertical angle as the third segment 329B approaches the electrical power source, and fillets 342B, 344B may be provided at this transition to provide increased structural support at these areas.

[0073] The opening 340B and other similar openings described herein may enable minimization of usage of precious metals. The opening 340B and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 336B, 338B.

[0074] In FIG. 3, modeling is illustrated depicting the electrical current distribution within the side 326B of the flange assembly. This modeling was done to see if additional improvements to the overall electrical current distribution could be achieved. Smaller segments included throughout the side 326B of the flange assembly indicate the general direction of electrical current at different locations within the flange assembly. In the side 326B, two different electrical current paths 348A, 348B are illustrated from the line 346 to the inner structure 318. The first electrical current path 348A travels from the line 346 through theSP24-215 first segment 336B and to the inner structure 318. The second electrical current path 348B travels from the line 346 through the second segment 338B and to the inner structure 318. The second electrical current path 348B is about 1.5333 times longer than the first electrical current path 348A. Resistance of an electrical current path depends on a cross-sectional size of different portions of the flange assembly that the path extends within, a length of the electrical current path, and a material resistivity for materials used within different portions of the flange assembly. Thus, with the sizes of the path-cross sections and material resistivity for paths 348A, 348B being about the same, the second electrical current path 348B may have a greater resistance relative to the first electrical current path 348A due to the greater length of the second electrical current path 348B. To make the paths 348A, 348B have similar resistances, the thickness or size of the first segment 336B may be decreased or the thickness or size of the second segment 338B may be increased. By decreasing the thickness or size of the first segment 336B, part of the electrical current flowing through the first segment 336B may instead flow through the second segment 338B, enabling improved electrical current density uniformity at the inner structure 318. In some embodiments, the thickness of the first segment 336B may be at least about 1.25 times smaller, at least about 1.5 times smaller, at least about 1.75 times smaller, or at least about 2 times smaller than the thickness of the second segment 338B.

[0075] Alternatively, the materials used at the first segment 336B or the second segment 338B may be adjusted, or the first segment 336B may be curved to effectively increase the length of the first electrical current path 348A. By designing the flange assembly so that all paths to the inner structure 318 have a similar resistance, a more uniform electrical current distribution may be accomplished at the inner structure 318 and at other locations within the flange assembly.

[0076] A similar material may be used throughout the side 326B of the flange assembly, making the material resistivity relatively similar throughout the flange assembly. However, the material resistivity may be different within the flange assembly where the temperature is significantly different in certain locations.

[0077] The electrical current density is between about 3.2 amps per square millimeter and about 3.6 amps per square millimeter proximate to the fillet 342B. However, the electrical current density is lower at other locations, with the electrical current density being between about 0 amps per square millimeter and about 0.4 amps per square millimeter at certain portionsSP24-215 of the central flange element 330 and at the junction between the second segment 338B and the third segment 329B.

[0078] FIG. 4 is a front view illustrating another example flange assembly 412 and the electrical current density at various locations on the flange assembly 412. Each of the features within the flange assembly 412 of FIG. 4 may be similar to corresponding features described in other embodiments. The flange assembly 412 includes a first side 426A and a second side 426B, with these two sides 426A, 426B being bisected by a midline 424. The first side 426A of the flange assembly 412 is made different from the second side 426B so that the effects of different geometries may be more easily seen.

[0079] The same features are present on both sides 426A, 426B, but the geometries used for different features on the two sides 426A, 426B are different. A single inner structure 418 is illustrated that is similar to the inner structure 318 of FIG. 3, and a central opening 420 is positioned in the inner structure 418 where a glass transfer tube may be received so that the glass transfer tube comes in contact with the inner structure 418. The inner structure 418 may be formed from one continuous disc, and the shape of the disc may generally share a shape similar to the central opening 420. Other inner structures described herein that do not include multiple portions therein may be similar to the inner structure 418.

[0080] The flange assembly 412 also includes an outer structure attached to the inner structure 418. The outer structure includes a central flange element 430, a first arm 428A, and a second arm 428B. The central flange element 430 includes an upper portion 431, a bottom portion 432, and two side portions 434A, 434B. The arms 428A, 428B may be connected to an electrical power source that may generate an electrical current that is conducted through the flange assembly to heat molten glass.

[0081] The first arm 428A includes a first segment 436A, a second segment 438A, and a third segment 429A. The first segment 436A, the second segment 438A, and the side portion 434A of the central flange element 430 surround the opening 440A. The third segment 429A of the first arm 428A transitions so that the third segment 429A extends to a vertical angle as the third segment 429A approaches the electrical power source, and fillets 442A, 444A may be provided at this transition to provide increased structural support at these areas.

[0082] The second arm 428B includes a first segment 436B, a second segment 438B, and a third segment 429B. The first segment 436B, the second segment 438B, and the side portion 434B of the central flange element 430 surround the opening 440B. The third segment 429B of the second arm 428B transitions so that the third segment 429B extends to a vertical angleSP24-215 as the third segment 429B approaches the electrical power source, and fillets 442B, 444B are provided at this transition to provide increased structural support at these areas.

[0083] The openings 440A, 440B and other similar openings described herein may enable minimization of usage of precious metals. The openings 440A, 440B and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 436A, 436B, 438A, 438B.

[0084] On the first arm 428 A, the first segment 436A and the second segment 438 A have about the same thickness DI. On the second arm 428B, the second segment 438B has a thickness similar to the thickness DI used for the first segment 436A, 438 A on the first side 426A. However, the first segment 436B has a thickness D2 that is less than the thickness DI. Due to the reduced thickness D2 at the first segment 436B, the opening 440B is made larger and the second side 426B is made with less material.

[0085] On the inner structure 418 at the first side 426A, the electrical current density generally falls between about 0.5 amps per square millimeter to about 1.5 amps per square millimeter. Thus, the electrical current density distribution across the inner structure 418 is fairly uniform on the first side 426A and may fall well below critical values.

[0086] On the inner structure 418 at the second side 426B, the electrical current density generally falls between about 0.5 amps per square millimeter to about 1.5 amps per square millimeter. Thus, the electrical current density distribution across the inner structure 418 is fairly uniform on the first side 426B and may fall well below critical values. However, the inner structure 418 has more areas that are lower than about 1.0 amps per square millimeter on the second side 426B compared to the first side 426A, and the electrical current density remains relatively constant around the inner structure 418 on the second side 426B. For example, at all locations around the curved path 450, the electrical current density is below 1 amp per square millimeter. Thus, by using the outer structure on the second side 426B, greater electrical current uniformity may be accomplished at the inner structure 418 while also using less material in the outer structure.

[0087] In the outer structure on the first side 426A, the electrical current density is at levels between about 3.5 amps per square millimeter and about 4.0 amps per square millimeter at small parts of the upper portion 431 and the bottom portion 432 that are closest to the inner structure 418. At other parts of the outer structure, the electrical current density may be lower, with the electrical current density ranging from about 1.0 amps per square millimeter to aboutSP24-2151.5 amps per square millimeter proximate to the location where the segments 436A, 438 A meet. Electrical current densities at other locations generally fall between about 1.5 amps per square millimeter and about 3.5 amps per square millimeter.

[0088] Despite the fact that the outer structure on the second side 426B uses less material than the outer structure on the first side 426A, the electrical current density is generally similar in the outer structure on the first side 426A and the second side 426B. In the outer structure on the second side 426B, the electrical current density is at levels between about 3.5 amps per square millimeter and about 4.0 amps per square millimeter at small parts of the upper portion 431 and the bottom portion 432 that are closest to the inner structure 418. At other parts of the outer structure, the electrical current density is lower, with the electrical current density ranging from about 1.0 amps per square millimeter to about 1.5 amps per square millimeter proximate to the location where the segments 436A, 438 A meet. Electrical current densities at other locations on the second side 426B generally fall between about 1.5 amps per square millimeter and about 3.5 amps per square millimeter.

[0089] Having areas with an excessively high electrical current density in the outer structure may result in local heating of the outer structure, and this local heating may result in added stress on the connection between the outer structure and the inner structure at the interface between the two. Thus, by using a design for flange assemblies like the ones illustrated on the first side 426A or the second side 426B, these issues may be mitigated.

[0090] FIG. 5 is a graph 566 illustrating how different rib thicknesses impact electrical current properties within a flange assembly. Points 566A illustrate the deviation of the maximum electrical current value from the average electrical current value for different thicknesses D2 for the segment 436B, with these values provided in terms of percentages. Points 566A are represented with circles. For the modelling that was done to obtain the results in the graph 566, the segment 438B was maintained at the same thickness as the thickness D2 of the segment 436B was adjusted. Points 566A may be obtained by subtracting the average electrical current value from the maximum electrical current value and by dividing that number by the average electrical current value. Points 566B are represented with squares. Points 566B illustrate the deviation of the minimum electrical current value from the average electrical current value for different rib thicknesses, with these values provided in terms of percentages. Points 566B may be obtained by subtracting the minimum electrical current value from the average electrical current value and by dividing that number by the average electrical current value. Points 566C are represented with triangles. Points 566C illustrate the standard deviationSP24-215 divided by the average electrical current value for different rib thicknesses, with these values provided in terms of percentages. Points 566C may be obtained by subtracting the standard deviation value from the average electrical current value and by dividing that number by the average electrical current value.

[0091] As illustrated, a substantial amount of deviation occurs for the minimum value and the standard deviation value at the highest thicknesses towards the left. However, relatively small electrical current deviation values may be accomplished when the thickness is about 76.2 millimeters (3 inches) or more. For points 566A (which shows deviation percentages of the maximum electrical current values), the percentages are about 62 percent at athickness of about 76.2 millimeters (3 inches), about 61.6 percent at a thickness of about 68.58 millimeters (2.7 inches), about 61 percent at a thickness of about 60.96 millimeters (2.4 inches), about 60.5 percent at a thickness of about 53.34 millimeters (2.1 inches), about 60 percent at athickness of about 45.72 millimeters (1.8 inches), about 59 percent at a thickness of about 38.1 millimeters (1.5 inches), about 60.5 percent at a thickness of about 30.48 millimeters (1.2 inches), and about 64.5 percent at a thickness of about 22.86 millimeters (0.9 inches). Thus, the lowest deviation percentage arose at a thickness of about 38.1 millimeters (1.5 inches).

[0092] For points 566B (which shows deviation percentages of minimum electrical current values), the percentages are about 52 percent at thicknesses of about 76.2 millimeters (3 inches), about 68.58 millimeters (2.7 inches), about 60.96 millimeters (2.4 inches), about 53.34 millimeters (2.1 inches), and about 45.72 millimeters (1.8 inches). For points 566B, the percentages are also about 51.5 percent at thicknesses of about 38.1 millimeters (1.5 inches), about 51 percent at a thickness of about 30.48 millimeters (1.2 inches), and about 50.5 percent at athickness of about 22.86 millimeters (0.9 inches). Thus, the lowest deviation percentages arose at thicknesses of about 38.1 millimeters (1.5 inches), about 30.48 millimeters (1.2 inches), and about 22.86 millimeters (0.9 inches), and the thickness of about 38.1 millimeters (1.5 inches) may be beneficial over smaller thicknesses to ensure that the segment provides sufficient structural strength and because the deviation percentages of the maximum electrical current values are greater at thicknesses of 30.48 millimeters (1.2 inches) and 22.86 millimeters (0.9 inches) than for a thickness of 38.1 millimeters (1.5 inches).

[0093] For points 566C (which shows deviation percentages of standard deviation values), the percentages are about 18.5 percent at thickness of about 76.2 millimeters (3 inches), about 68.58 millimeters (2.7 inches), about 60.96 millimeters (2.4 inches), and about 53.34 millimeters (2.1 inches). The percentages are about 19 percent at a thickness of about 45.72SP24-215 millimeters (1.8 inches), about 20.5 percent at a thickness of about 38.1 millimeters (1.5 inches), about 22.5 percent at a thickness of about 30.48 millimeters (1.2 inches), and about 24.5 percent at a thickness of about 22.86 millimeters (0.9 inches).

[0094] Where the line graph 566 indicates C-l, this corresponds to data obtained using a design concept similar to the one illustrated in side 926A in FIG. 11 where the top rib thickness was around 50.8 millimeters (2 inches). The point 566A corresponding to this design concept is at about 71.5 percent, and the point 566C corresponding to this design concept is at about 29 percent.

[0095] FIG. 6 is a line graph 668 illustrating the normalized electrical current density at various points around inner structures for different flange assembly designs. A position value is used as the variable on the x-axis, with this position being the position along a curved path on the respective inner structures. For example, the line 668D presents a normalized electrical current density for the second side 426B of FIG. 4 at various positions along the curved path 450. The 0.0 position corresponds to the position at the beginning of the curved path 450 near the bottom of the inner structure 418. The maximum position corresponds to the position at the end of the curved path 450 near the top of the inner structure 418. For example, the point 452 may correspond to a position of about 0.10 meters.

[0096] The line 668A presents a best theoretical normalized electrical current density at various positions along a curved path similar to the curved path 1250A of FIG. 12. The line 668B presents a normalized electrical current density for the embodiment illustrated in FIG. 9 at various positions along the curved path 950. The line 668C presents a normalized electrical current density for the first side 1226A illustrated in FIG. 12 at various positions along the curved path 1250A when the thickness D7 is about 76.2 millimeters (3 inches). The line 668D presents a normalized electrical current density for the second side 426B illustrated in FIG. 4 at various positions along the curved path 450 when the thickness D2 is about 38.1 millimeters (1.5 inches).

[0097] For the line 668A, the normalized electrical current density generally remains about 1.55 amps per square millimeter. For the line 668B, the minimum electrical current density is about 0.72 amps per square millimeter and the maximum electrical current density is about 2.22 amps per square millimeter. Thus, for the line 668B, the maximum electrical current density was about 3.08 times the minimum electrical current density. For the line 668C, the minimum electrical current density is about 1.08 amps per square millimeter and the maximum electrical current density is about 1.88 amps per square millimeter. Thus, for the line 668C,SP24-215 the maximum electrical current density was about 1.74 times the minimum electrical current density. For the line 668D, the minimum electrical current density is about 1.18 amps per square millimeter and the maximum electrical current density is about 1.73 amps per square millimeter. Thus, for the line 668D, the maximum electrical current density was about 1.47 times the minimum electrical current density, which was a smaller number than any of the other designs represented in FIG. 6. Thus, by using a smaller rib thickness for the segment 436B, the electrical current uniformity within the inner structure may be improved. The minimum electrical current densities all occurred at the zero position, which corresponds to the bottom of the inner structure.

[0098] FIG. 7 is a front view illustrating another example flange assembly 712. Each of the features within the flange assembly 712 of FIG. 7 may be similar to corresponding features described in other embodiments. The flange assembly 712 includes a first side 726A and a second side 726B, with these two sides 726A, 726B being bisected by a midline 724. The first side 726A and the second side 726B are symmetrical to each other.

[0099] The flange assembly includes an inner structure 718, and the flange assembly 712 also includes an outer structure attached to the inner structure 718. The outer structure includes a central flange element 730, a first arm 728A, and a second arm 728B. The central flange element 730 includes an upper portion 731, a bottom portion 732, and two side portions 734A, 734B. The arms 728A, 728B may be connected to an electrical power source that may generate an electrical current that is conducted through the flange assembly 712 to heat molten glass. The central opening 720 has a shape similar to the central opening 120 of FIG. 1C, and the central opening 720 may be configured to receive a glass transfer tube with a similar cross- sectional shape. However, the central opening 720 may possess another shape (e.g., a circular shape, a shape with a width greater than the height, etc.) in other embodiments.

[0100] The first arm 728 A includes a first segment 736 A, a second segment 738 A, and a third segment 729A. The first segment 736A, the second segment 738A, and the left-side portion 734 A of the central flange element 730 surround the opening 740 A. The third segment 729A of the first arm 728A generally extends at the same angle as it approaches the electrical power source, with the third segment 729A extending in a direction that is offset about 45 degrees relative to the horizontal. However, the third segment 729A may be offset at other angles relative to the horizontal. For example, the third segment 729A may be offset by about 30 degrees to about 60 degrees relative to the horizontal in other embodiments, or the third segment 729 A may be modified so that it extends vertically.SP24-215

[0101] The second arm 728B includes a first segment 736B, a second segment 738B, and a third segment 729B. The first segment 736B, the second segment 738B, and the right-side portion 734B of the central flange element 730 surround the opening 740B. The third segment 729B of the second arm 728B generally extends at the same angle as the third segment 729B approaches the electrical power source, with the third segment 729B extending in a direction that is offset about 45 degrees relative to the horizontal. However, the third segment 729B may be offset at other angles relative to the horizontal. For example, the third segment 729B may be offset by about 30 degrees to about 60 degrees relative to the horizontal in other embodiments, or the third segment 729B may be modified so that the third segment 729B extends vertically.

[0102] The shape of the openings 740A, 740B is different from the shape of the openings described above. The openings 740A, 740B have a rough rounded scalene triangle-like shape, with a horizontally extending wall formed at the bottom of the openings 740A, 740B. Relative to other openings described above, the openings 740A, 740B include additional material in areas 754A, 754B proximate to the horizontally extending wall. The area 754A is positioned at the junction between the second segment 738A of the first arm 728A and the left-side portion 734A of the central flange element 730, and the area 754B is positioned at the junction between the second segment 738B of the second arm 728B and the right-side portion 734B of the central flange element 730.

[0103] The openings 740A, 740B and other similar openings described herein may enable minimization of usage of precious metals. The openings 740A, 740B and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 736A, 736B, 738A, 738B. The inclusion of additional material at the areas 754A, 754B may be beneficial in some designs to shorten the electrical current paths to certain parts of the side portions 734A, 734B and to improve electrical current density uniformity.

[0104] FIG. 8 is a front view illustrating a portion of another example flange assembly 812. This flange assembly 812 may generally be similarto the flange assembly 712 in most respects, but the opening 840A is different from the opening 740A of FIG. 7. In the portion of the flange assembly 812 that is shown, portions of the first arm 828A and the central flange element 830 of the outer structure are visible. The first arm 828A includes a first segment 836A, a second segment 838A, and athird segment 829A. The first segment 836A, the second segment 838A, and the side portion 834A of the central flange element 830 surround the opening 840A.SP24-215

[0105] The main distinction between the flange assembly 812 and the flange assembly 712 of FIG. 7 is the openings that are present. The openings 740A, 740B are smaller than the opening 840A due to the additional material at the areas 754A, 754B. Less material is included at these corresponding areas in the flange assembly 812 such that the opening 840A is made larger. While only a portion of the flange assembly 812 is illustrated on the first arm 828A, the flange assembly 812 may be symmetrical such that the second arm (not shown) possesses similar features and a similar geometry.

[0106] The opening 840A and other similar openings described herein may enable minimization of usage of precious metals. The opening 840A and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses ofthe segments 836A, 838A.

[0107] FIG. 9 is a front view illustrating one side 926A of another example flange assembly, with the electrical current density at various locations being shown on the side 926A. Each of the features within the side 926A may be similar to the corresponding features within the flange assembly 812 of FIG. 8. The flange assembly includes an inner structure 918 and an outer structure. The inner structure 918 surrounds the central opening 920 where a glass transfer tube may be received. The inner structure 918 comprises platinum, but other metals or metal alloys may be used in place of platinum in other embodiments. The outer structure includes a central flange element 930, a first arm 928A, and a second arm (not shown). The central flange element 930 includes an upper portion 931, a bottom portion 932, a left-side portion 934A, and a right-side portion (not shown).

[0108] The first arm 928A includes a first segment 936A, a second segment 938A, and a third segment 929A. The first segment 936A, the second segment 938A, and the left-side portion 934A of the central flange element 930 surround the opening 940A. The third segment 929A of the first arm 928A generally extends at the same angle as the third segment 929A approaches the electrical power source, with the third segment 929A extending in a direction that is offset about 45 degrees relative to the horizontal. However, the third segment 929A may be offset at other angles relative to the horizontal.

[0109] The opening 940A and other similar openings described herein may enable minimization of usage of precious metals. The opening 940A and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses ofthe segments 936A, 938A.SP24-215

[0110] A single inner structure 918 is illustrated, but the inner structure 918 may comprise different sections in some embodiments. The inner structure 918 may comprise platinum. On the inner structure 918 at the side 926A, the electrical current density generally falls between about 0.4 amps per square millimeter to about 2.5 amps per square millimeter. The electrical current density is relatively low at upper and lower portions of the inner structure 918, and the electrical current density is relatively high at the side portions of the inner structure 918.

[0111] While the electrical current distribution in the inner structure 918 is fairly uniform, the electrical current distribution on the outer structure is not. In the outer structure, the electrical current density is at levels between about 4 amps per square millimeter and about 4.5 amps per square millimeter at certain parts of the upper portion 931, the bottom portion 932, the left-side portion 934A, and at elevated portions on the third segment 929A. At other parts of the outer structure, the electrical current density may be lower, with the electrical current density ranging from about 1.5 amps per square millimeter to about 2.0 amps per square millimeter proximate to the location where the segments 936A, 938 A meet and the location where the second segment 938 A connects to the central flange element 930. Electrical current densities at other locations generally fall between about 2 amps per square millimeter and about 4 amps per square millimeter. Having areas with an excessively high electrical current density in the outer structure may result in localized heating of the outer structure, and this localized heating may result in added stress on the connection between the outer structure and the inner structure at the interface between the two.

[0112] A side 1026B of another example flange assembly and various dimensions for the flange assembly are illustrated in the front view of FIG. 10. Each of the features within the side 1026B of FIG. 10 may be similar to corresponding features described in reference to the embodiments illustrated in FIGS. 7 and 8.

[0113] The inner structure 1018 includes a first portion 1018A and the second portion 1018B. The first portion 1018A and the second portion 1018B may both comprise platinum, and the compositions of the first portion 1018 A and the second portion 1018B may be different in some embodiments. For example, other metals or metal alloys may be used in place of platinum in other embodiments. The second portion 1018B is positioned inwardly relative to the first portion 1018A. While a first portion 1018A and a second portion 1018B are illustrated in the embodiment of FIG. 10, additional portions may be used in other embodiments, and each portion may have a different composition. The portions 1018A, 1018B may be attached together using welding or another attachment approach.SP24-215

[0114] The flange assembly 1012 also includes an outer structure attached to the inner structure 1018. The outer structure includes a central flange element 1030, a first arm (not shown), and a second arm 1028B. The central flange element 1030 includes an upper portion 1031, a bottom portion 1032, a left-side portion (not shown), and a right-side portion 1034B. The arms may be connected to an electrical power source that may generate an electrical current that is conducted through the flange assembly to heat molten glass. The central opening 1020 has a shape similar to the central opening 120 of FIG. 1C, and the central opening 1020 may be configured to receive a glass transfer tube with a similar cross-sectional shape. However, the central opening 1020 may possess another shape (e.g., a circular shape, a shape with a width greater than the height, etc.) in other embodiments.

[0115] The second arm 1028B includes a first segment 1036B, a second segment 1038B, and a third segment 1029B. The first segment 1036B, the second segment 1038B, and the right-side portion 1034B of the central flange element 1030 surround the opening 1040B. The third segment 1029B of the second arm 1028B generally extends at the same angle as the third segment 1029B approaches the electrical power source, with the third segment 1029B extending in a direction that is offset about 45 degrees relative to the horizontal. However, the third segment 1029B may be offset at other angles relative to the horizontal.

[0116] The shape of the openings 1040A, 1040B is similar in some respects to the openings 740A, 740B of FIG. 7. The openings 1040A, 1040B include additional material in areas 1054A, 1054B. In other embodiments described herein, material is not included in corresponding areas and the openings are instead made larger. The area 1054B is positioned at the junction between the second segment 1038B of the second arm 1028B and the right-side portion 1034B of the central flange element 1030.

[0117] The opening 1040B and other similar openings described herein may enable minimization of usage of precious metals. The opening 1040B and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 1036B, 1038B.

[0118] The first segment 1036B generally extends lengthwise along the line 1064A. This line 1064A may define an angle 63 relative to the horizontal. This angle 63 is about 19.8 degrees, but the angle 63 may possess different values in other embodiments. The first segment 1036B also defines a thickness D5.SP24-215

[0119] The second segment 1038B generally extends lengthwise along the line 1064B. This line 1064B may define an angle 04 relative to the horizontal. This angle 04 is about 45 degrees, but the angle 04 may possess different values in other embodiments. The second segment 1038B defines a thickness D6.

[0120] Additionally, the upper portion 1031 of the central flange element 1030 defines a thickness D3 at the uppermost part of the central flange element 1030. The bottom portion 1032 of the central flange element 1030 defines a thickness D4 at the lowest part of the central flange element 1030.

[0121] The central opening 1020 defines first center point 1056A and a second center point 1056B. The first center point 1056A defines the center of the rounded circular shape at the top of the central opening 1020. The second center point 1056B defines the center of the rounded circular shape at the bottom of the central opening 1020. The distance between the first center point 1056A and the second center point 1056B may define the length of the straight portions at the sides of the central opening 1020.

[0122] The first segment 1036B extends out in a lengthwise direction along the line 1064A from a first point 1060 defined at the interface between the inner structure 1018 and the central flange element 1030. A line extends through the first point 1060 and the first center point 1056A, and this line defines a connection angle 01 relative to the horizontal. The connection angle 01 is about 30.86 degrees, but the connection angle 01 may possess different values in other embodiments.

[0123] The second segment 1038B extends out in a lengthwise direction along the line 1064B from a second point 1062 defined at the interface between the inner structure 1018 and the central flange element 1030. A line extends through the second point 1062 and the second center point 1056B, and this line defines a connection angle 02 relative to the horizontal. The connection angle 02 is about 54.07 degrees, but the connection angle 02 may possess different values in other embodiments.

[0124] The geometry of the side 1026B of the flange assembly may be adjusted to adjust the amount of precious metals that are used, to alter the flow of electrical current through the second arm 1028B to the inner structure 1018, to enable attachment to other components (e.g., to electrical power source(s)), etc. For example, values such as the angles 01-04, the thicknesses D3-D6, and the thickness may be adjusted in other embodiments.

[0125] A parametric modeling effort was performed to understand the impact on the geometry of the various features in the outer structures of flanges assemblies. This effort wasSP24-215 undertaken to identify designs that improve the overall electrical current distribution while using a limited amount of precious metals. Various designs are illustrated and described herein that lead to improvements in the overall electrical current distribution while limiting the amount of precious metals that are used. For example, the flange assembly 212 and the flange assembly 412 may possess improved electrical current distributions relative to existing flange assemblies. The electrical current distributions may be improved by reducing the maximum electrical current density and by reducing the electrical current density variability.

[0126] FIG. 11 is a front view illustrating one side 926A of one example flange assembly positioned adjacent to a side 1126B of another example flange assembly so that impact of the design for the two flange assemblies on the electrical current density may be seen. Each of the features within the sides 926A, 1126B of FIG. 11 may be similar to corresponding features described in other embodiments.

[0127] The two sides 926A, 1126B are positioned on opposing sides of the midline 1124. The same features are present on both sides 926A, 1126B, but the geometries used for different features on the two sides 926A, 1126B are different. On each of the sides 926A, 1126B, a single inner structure 1118 is illustrated, and a central opening 1120 is positioned in the inner structure 1118 where a glass transfer tube may be received so that the glass transfer tube comes in contact with the inner structure 1118. The inner structure 1118 comprises platinum, but other metals or metal alloys may be used in place of platinum in other embodiments.

[0128] Like the internal openings defined by support assemblies, the central opening 1120 may define a width-to-height ratio that is less than 1. This width-to-height ratio is the width of the central opening 1120 divided by the height of the central opening 1120. In some embodiments, the width-to-height ratio may be between about 0.5 and about 0.9, between about 0.6 and about 0.8, between about 0.65 and about 0.75. In the illustrated embodiment, the width- to-height ratio is about 0.7.

[0129] The side 926A also includes an outer structure attached to the inner structure 1118. The outer structure on the side 926A may be similar to the outer structure illustrated in FIG. 9 and described herein. A second arm may be positioned opposite the first arm 928A but is not shown here.

[0130] The side 1126B includes an outer structure attached to the inner structure 1118. The outer structure includes a central flange element 1130B and a second arm 1128B. The central flange element 1130B includes an upper portion 113 IB, a bottom portion 1132B, a left-side portion (not shown), and a right-side portion 1134B. The arms 928A, 1128B may be connectedSP24-215 to an electrical power source that may generate an electrical current that is conducted through the flange assembly to heat molten glass.

[0131] The second arm 1128B includes a first segment 1136B, a second segment 1138B, and a third segment 1129B. The first segment 1136B, the second segment 1138B, and the right-side portion 1134B of the central flange element 1130B surround the opening 1140B. The third segment 1129B of the second arm 1128B transitions so that the third segment 1129B extends to a vertical angle as the third segment 1129B approaches the electrical power source, and fillets 1142B, 1144B are provided at this transition to provide increased structural support at these areas. A fillet 1170B is also provided at the junction between the segments 1136B, 1138B to provide added structural support at this area.

[0132] On the first arm 928A, the first segment 936A and the second segment 938A have about the same thickness. On the second arm 1128B, the first segment 1136B and the second segment 1138B also have about the same thickness, but this thickness is greater than the thickness of the segments 936A, 938A.

[0133] The openings 940A, 1140B, and other similar openings described herein may enable minimization of usage of precious metals. The openings 940A, 1140B and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 936A, 938A, 1136B, 1138B.

[0134] The second side 1126B includes a geometry similar to the first side 426A in FIG. 4, and the electrical current density within the second side 1126B may be similar to the electrical current density in the first side 426A. As illustrated in FIG. 11, the electrical current density is significantly higher at certain locations on the first side 926A relative to the second side 1126B.

[0135] In the outer structure at the side 926A, the electrical current density is at levels between about 4 amps per square millimeter and about 4.5 amps per square millimeter at substantial areas of the upper portion 931, the bottom portion 932, and the left-side portion 934A and at elevated portions on the third segment 929A. By contrast, in the outer structure at the second side 1126B, the electrical current density is just above 3.5 amps per square millimeter at small areas on the upper portion 113 IB and the bottom portion 1132B closest to the inner structure 1118, but the electrical current density is generally under 3 amps per square millimeter at other areas.SP24-215

[0136] FIG. 12 is a front view illustrating a first side 1226A of one example flange assembly positioned adjacent to a second side 1226B of another example flange assembly so that impact of the design for the two flange assemblies on the electrical current density may be seen. Each of the features within the sides 1226A, 1226B of FIG. 12 may be similar to corresponding features described in other embodiments, but the geometries for the sides may be different from other embodiments. The geometry used for the first side 1226A may be similar to the geometry used for the first side 426A, and the electrical current density for the first side 1226A is therefore similar to the electrical current density obtained for the first side 426A.

[0137] The two sides 1226A, 1226B are positioned on opposing sides of the midline 1224. The same features are present on both sides 1226A, 1226B, but the geometries used for different features on the two sides 1226A, 1226B are different. On each of the sides 1226A, 1226B, a single inner structure 1218 is illustrated that is similar to the inner structure 1118 of FIG. 11, and a central opening 1220 is positioned in the inner structure 1218 where a glass transfer tube may be received so that the glass transfer tube comes in contact with the inner structure 1218. The inner structure 1218 comprises platinum, but other metals or metal alloys may be used in place of platinum in other embodiments. Like the internal openings defined by support assemblies, the central opening 1220 may define a width -to-height ratio that is less than 1. This width-to-height ratio is the width of the central opening 1220 divided by the height of the central opening 1220. In some embodiments, the width-to-height ratio may be between about 0.5 and about 0.9, between about 0.6 and about 0.8, between about 0.65 and about 0.75. In the illustrated embodiment, the width-to-height ratio is about 0.7.

[0138] The first side 1226A also includes an outer structure attached to the inner structure 1218. The outer structure includes a central flange element 1230A and a first arm 1228A. The central flange element 1230A includes an upper portion 1231 A, a bottom portion 1232A, a leftside portion 1234A, and a right-side portion (not shown). A second arm may be positioned opposite the first arm 1228A, but is not shown here.

[0139] The second side 1226B also includes an outer structure attached to the inner structure 1218. The outer structure includes a central flange element 1230B and a second arm 1228B. The central flange element 1230B includes an upper portion 123 IB, a bottom portion 1232B, a left-side portion (not shown), and a right-side portion 1234B. The arms 1228A, 1228B may be connected to an electrical power source that may generate an electrical current that is conducted through the flange assembly to heat molten glass.SP24-215

[0140] The first arm 1228A includes a first segment 1236A and a second segment 1238A and athird segment 1229A. The first segment 1236A, the second segment 1238A, and the leftside portion 1234A of the central flange element 1230A surround an opening 1240A. The third segment 1229A of the first arm 1228A transitions so that the third segment 1229A extends to a vertical angle as the third segment 1229A approaches the electrical power source, and fillets 1242A, 1244A are provided at this transition to provide increased structural support at these areas.

[0141] The second arm 1228B includes a first segment 1236B, a second segment 1238B, and a third segment 1229B. The first segment 1236B, the second segment 1238B, and the right-side portion 1234B of the central flange element 1230B surround the opening 1240B. The third segment 1229B of the second arm 1228B transitions so that the third segment 1229B extends to a vertical angle as the third segment 1229B approaches the electrical power source, and fillets 1242B, 1244B are provided at this transition to provide increased structural support at these areas.

[0142] The fillet 1242B on the second side 1226B may have a smaller size relative to the fillet 1242A on the first side 1226A, with the fillet 1242B having a radius of curvature of about 76.2 millimeters (3 inches). Additionally, the fillet 1244B on the second side 1226B has a larger size relative to the fillet 1244A on the first side 1226A, with the fillet 1244B having a radius of curvature of between about 381 millimeters (15 inches) and about 533.4 millimeters (21 inches). However, in some embodiments, the fillet 1244B may have an even larger radius of curvature of about 533.4 millimeters (21 inches) or more. A thickness of the third segment 1229B on the second side 1226B is made smaller than the thickness of the third segment 1229A on the first side 1226A. In some embodiments, the thickness of the third segment 1229B may be between about 101.6 millimeters (4 inches) and about 114.3 millimeters (4.5 inches).

[0143] On the first arm 1228A, the first segment 1236A and the second segment 1238A have about the same thickness D7. On the second arm 1228B, the first segment 1236B and the second segment 1238B also have about the same thickness D8, and the thicknesses D7, D8 are equal to each other.

[0144] The openings 1240A, 1240B and other similar openings described herein may enable minimization of usage of precious metals. The openings 1240A, 1240B and other similar openings described herein may enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 1236A, 1236B, 1238A, 1238B.SP24-215

[0145] In the outer structure at the first side 1226A, the electrical current density is at levels between about 3.5 amps per square millimeter and about 4.0 amps per square millimeter at the fillet 1242B and at small parts of the upper portion 1231 and the bottom portion 1232 that are closest to the inner structure 1218. At other parts of the outer structure, the electrical current density may be lower, with the electrical current density ranging from about 1 amp per square millimeter to about 1.5 amps per square millimeter proximate to the location where the segments 1236A, 1238 A meet. Electrical current densities at other locations generally fall between about 1.5 amps per square millimeter and about 3.5 amps per square millimeter. While similar electrical current densities are accomplished on both sides 1226A, 1226B, the design on second side 1226B may use a lower amount of metal material, allowing this design to be made in a more cost-effective manner.

[0146] In the first side 1226A, the fillet 1270A may be positioned at an edge of the opening 1240A at a location where the segments 1236A, 1238A meet. In the second side 1226B, the fillet 1270B may be positioned at an edge of the opening 1240B at a location where the segments 1236B, 1238B meet. The fillet 1270B is larger than the fillet 1270A, with the fillet 1270B having a radius of curvature of between about 101.6 millimeters (4 inches) and about 152.4 millimeters (6 inches).

[0147] FIG. 13 is a graph 1372 illustrating how different sizes for the fillet radius of the fillet 1244B in FIG. 12 impacts electrical current properties within a flange assembly. Points 1372A illustrate the deviation of the minimum electrical current value from the average electrical current value for different fillet radiuses for fillet 1244B, with these values provided in terms of percentages. Points 1372A may be obtained by subtracting the minimum electrical current value from the average electrical current value and by dividing that number by the average current value. Points 1372B illustrate the deviation of the maximum electrical current value from the average electrical current value for different fillet radiuses for fillet 1244B, with these values provided in terms of percentages. Points 1372B may be obtained by subtracting the average electrical current value from the maximum electrical current value and by dividing that number by the average electrical current value. Points 1372C illustrate the standard deviation divided by the average electrical current value for different fillet radiuses for fillet 1244B, with these values provided in terms of percentages. Points 1372C may be obtained by subtracting the standard deviation value from the average electrical current value and by dividing that number by the average electrical current value.SP24-215

[0148] As illustrated, a substantial amount of deviation occurs for the minimum value and the standard deviation value at the lowest fdlet radius. However, relatively small electrical current deviation values may be accomplished when the fdlet radius is about 381 millimeters (15 inches) or more. Points 1372A are represented with squares. For points 1372A (which shows deviation percentages of the minimum electrical current values), the percentages are about 54 percent at a fdlet radius of about 381 millimeters (15 inches), about 52.8 percent at a fdlet radius of about 457.2 millimeters (18 inches), and about 52.8 percent at a fdlet of about 533.4 millimeters (21 inches). Points 1372B are represented with circles. For points 1372B (which shows deviation percentages of maximum electrical current values), the percentages are about 63 percent at a fdlet radius of about 381 millimeters (15 inches), about 62 percent at a fdlet radius of about 457.2 millimeters (18 inches), and about 62 percent at a fdlet radius of about 533.4 millimeters (21 inches). Points 1372C are represented with triangles. For points 1372C (which shows deviation percentages of standard deviation values), the percentages are about 21.5 percent at a fdlet radius of about 381 millimeters (15 inches), about 20 percent at a fdlet radius of about 457.2 millimeters (18 inches), and about 20 percent at a fdlet radius of about 533.4 millimeters (21 inches).

[0149] These deviation percentages are in line with the deviation percentages when smaller radiuses are used, and the larger fdlet radius for the fdlet 1244B may enable a lower amount of material to be used. For example, points 1372A generally fall between about 52 percent and about 53 percent for radiuses between about 50.8 millimeters (2 inches) and about 304.8 millimeters (12 inches), points 1372B generally fall between about 61.6 percent and about 63 percent for radiuses between about 50.8 millimeters (2 inches) and about 304.8 millimeters (12 inches), and points 1372C generally fall between about 18 percent and about 21 percent for radiuses between about 50.8 millimeters (2 inches) and about 304.8 millimeters (12 inches).

[0150] Where the line graph 1372 indicates C-l, this corresponds to data obtained using a design concept similar to the one illustrated in side 926A in FIG. 11, and where the line graph 1372 indicates C-2, this corresponds to data obtained using a design concept similar to the one illustrated in side 926B of FIG. 11 where a fillet radius of about 152.4 millimeters (6 inches) was used. The point 1372A corresponding to the C-l design concept is at about 71.5 percent, and the point 1372C corresponding to the C-l design concept is at about 29 percent. The point 1372A corresponding to the C-2 design concept is at about 52 percent, the point 1372B corresponding to the C-2 design concept is at about 62 percent, and the point 1372C corresponding to the C-2 design concept is at about 19 percent.SP24-215

[0151] FIG. 14 is a line graph 1474 illustrating the normalized electrical current density at various points around inner structures for different flange assembly designs. A position value is used as the variable on the x-axis, with this position being the position along a curved path on the respective inner structures. For example, the line 1474B presents a normalized electrical current density for the embodiment illustrated in FIG. 9 at various positions along the curved path 950. The 0.0 position corresponds to the position at the beginning of the curved path 950 near the bottom of the inner structure 918. The maximum position corresponds to the position at the end of the curved path 950 near the top of the inner structure 918.

[0152] The line 1474A presents a best theoretical normalized electrical current density at various positions along the curved path similar to the curved path 1250A of FIG. 12. The line 1474B presents a normalized electrical current density for the embodiment illustrated in FIG. 9 at various positions along the curved path 950. The line 1474C presents a normalized electrical current density for the first side 1226A illustrated in FIG. 12 at various positions along the curved path 1250A. The line 1474D presents a normalized electrical current density for the second side 1226B illustrated in FIG. 12 at various positions along the curved path 1250B.

[0153] For the line 1474A, the normalized electrical current density generally remains about 1.55 amps per square millimeter. For the line 1474B, the minimum electrical current density is about 0.72 amps per square millimeter and the maximum electrical current density is about 2.22 amps per square millimeter. Thus, for the line 1474B, the maximum electrical current density was about 3.08 times the minimum electrical current density. For the line 1474C, the minimum electrical current density is about 1.08 amps per square millimeter and the maximum electrical current density is about 1.88 amps per square millimeter. Thus, for the line 1474B, the maximum electrical current density was about 1.74 times the minimum electrical current density. For the line 1474D, the minimum electrical current density is about 1.11 amps per square millimeter and the maximum electrical current density is about 1.82 amps per square millimeter. Thus, for the line 1474B, the maximum electrical current density was about 1.64 times the minimum electrical current density. The minimum electrical current densities all occurred at the zero position, which corresponds to the bottom of the inner structure.

[0154] FIG. 15 is a front view illustrating a first side 1526A of one example flange assembly positioned adjacent to a second side 1526B of another example flange assembly so that differences in the design for the two flange assemblies may be seen. Each of the featuresSP24-215 within the sides 1526A, 1526B of FIG. 15 may be similar to corresponding features described in other embodiments.

[0155] The two sides 1526A, 1526B are positioned on opposing sides of the midline 1524. The same features are generally present on both sides 1526A, 1526B, but the geometries used for different features on the two sides 1526A, 1526B are different. On each of the sides 1526A, 1526B, a single inner structure 1518 is illustrated, and a central opening 1520 is positioned in the inner structure 1518 where a glass transfer tube may be received so that the glass transfer tube comes in contact with the inner structure 1518. The inner structure 1518 comprises platinum, but other metals or metal alloys may be used in place of platinum in other embodiments. The central opening 1520 has a shape similar to the central opening 120 of FIG. 1C, and the central opening 1520 may be configured to receive a glass transfer tube with a similar cross-sectional shape. However, the central opening 1520 may possess another shape (e.g., a circular shape, a shape with a width greater than the height, etc.) in other embodiments.

[0156] The first side 1526A also includes an outer structure attached to the inner structure 1518. The outer structure includes a central flange element 1530A and a first arm 1528A. The central flange element 1530A includes an upper portion 1531A, a bottom portion 1532A, aleft- side portion 1534A, and a right-side portion (not shown). A second arm may be positioned opposite the first arm 1528A, but is not shown here.

[0157] The second side 1526B also includes an outer structure attached to the inner structure 1518. The outer structure includes a central flange element 1530B and a second arm 1528B. The central flange element 1530B includes an upper portion 153 IB, a bottom portion 1532B, a left-side portion (not shown), and a right-side portion 1534B.

[0158] The arms 1528A, 1528B may be connected to an electrical power source that may generate an electrical current that is conducted through the flange assembly to heat molten glass. The first arm 1528A includes a first segment 1536A, a second segment 1538A, a third segment 1529A. The first segment 1536A, the second segment 1538A, and the left-side portion 1534A of the central flange element 1530A surround an opening 1540A. The third segment 1529A of the first arm 1528A transitions so that the third segment 1529A extends to a vertical angle as the third segment 1529A approaches the electrical power source, and fillets 1542A, 1544A are provided at this transition to provide increased structural support at these areas. The third segment 1529A defines a thickness D9 at the region where the third segment 1529A is extending vertically.SP24-215

[0159] The second arm 1528B includes a first segment 1536B, a second segment 1538B, and a third segment 1529B. The first segment 1536B, the second segment 1538B, and the right-side portion 1534B of the central flange element 1530B surround the opening 1540B. The third segment 1529B of the second arm 1528B transitions so that the third segment 1529B extends to a vertical angle as the third segment 1529B approaches the electrical power source, and fillets 1542B, 1544B are provided at this transition to provide increased structural support at these areas. A fillet 1570B is also included at the junction between the first segment 1536B and the second segment 1538B. The third segment 1529B defines a thickness DIO at the region where the third segment 1529B is extending vertically. This thickness DIO is larger than the thickness D9 of the third segment 1529A of the first arm 1528A. In some embodiments, the thickness D9 of the third segment 1529A may be between about 101.6 millimeters (4 inches) and about 114.3 millimeters (4.5 inches).

[0160] The openings 1540A, 1540B and other similar openings described herein may enable minimization of usage of precious metals. The openings 1540A, 1540B and other similar openings described herein may also enable electrical current flow uniformity as the electrical current density may be optimized by changing parameters such as the thicknesses of the segments 1536A, 1536B, 1538A, 1538B.

[0161] On the first arm 1528A, the first segment 1536A and the second segment 1538A have different thicknesses, with the thickness of the second segment 1538A being greater than the thickness of the first segment 1536A. Additionally, the first segment 1536A is curved, but the second segment 1538A is straight. Including curvature in the first segment 1536A may be beneficial to increase the distance that electrical current must travel from an electrical power source to the inner structure 1518, thereby increasing the resistance of the path and altering the electrical current density. Doing this may be beneficial to obtain improved electrical current density uniformity within flange assemblies and within the inner structure 1518. In some embodiments, both segments 1536A, 1538B may be curved. For example, the second segment 1538A may be curved so that the electrical current path becomes shorter. On the second arm 1528B, the first segment 1536B and the second segment 1538B have about the same thickness, but this thickness is greater than the thickness of the segments 1536A, 1538A. The two segments 1536B, 1538B are both straight.

[0162] The inner structure 1518 includes a first portion 1518A and the second portion 1518B. The first portion 1518A and the second portion 1518B may both comprise platinum, and the compositions of the first portion 1518 A and the second portion 1518B may be differentSP24-215 in some embodiments. The second portion 1518B is positioned inwardly relative to the first portion 1518A. While a first portion 1518A and a second portion 1518B are illustrated in the embodiment of FIG. 15, additional portions may be used in other embodiments, and each portion may have a different composition. The portions 1518A, 1518B may be attached together using welding or another attachment approach.

[0163] On the first side 1526A illustrated in FIG. 15, additional openings are included relative to other embodiments described herein. A first additional opening 1576A is formed in the central flange element 1530A proximate to the first segment 1536A. The first additional opening 1576A is positioned proximate to the junction between the first segment 1536A, the upper portion 1531A of the central flange element 1530A, and the left-side portion 1534A of the central flange element 1530A. A second additional opening 1576B is also formed in the central flange element 1530A proximate to the second segment 1538A. The second additional opening 1576B is positioned proximate to the junction between the second segment 1538A, the bottom portion 1532A ofthe central flange element 1530A, and the left-side portion 1534A of the central flange element 1530A. The additional openings 1576A, 1576B may enable the flange assembly illustrated on the first side 1526Ato be made with less material and to be made in a more cost-effective manner relative to the second side 1526B. The inclusion of the additional openings 1576A, 1576B may also enable a reduction of electrical current density peaks that may otherwise be present on the inner structure 1518.

[0164] The upper portion 1531A on the first side 1526A has a reduced size relative to the upper portion 153 IB on the second side 1526B, and the bottom portion 1532A on the first side 1526A has a reduced size relative to the bottom portion 1532B on the second side 1526B. This may enable the flange assembly illustrated on the first side 1526A to be made with less material and to be made in a more cost-effective manner relative to the second side 1526B.

[0165] On the first side 1526A, the fillet 1544A has a radius of curvature of between about 381 millimeters (15 inches) and about 508 millimeters (20 inches), and this may allow for a reduction of material at the intersection of the segments 1529A, 1536A, 1538A. This intersection is where the electrical current density is typically the lowest in other embodiments, so removal of material at this intersection may be done without causing an excessively high electrical current density at the intersection. On the first side 1526A, the fillet 1570A has an increased size of between about 101.6 millimeters (4 inches) and 152.4 millimeters (6 inches) in radius of curvature. The size of this fillet 1570 A may allow a thickness ofthe second segment 1538A to be maintained at the same thickness used in other embodiments.SP24-215

[0166] Support assemblies are also contemplated for providing support to glass transfer tubes, and these support assemblies may be distinct and separate components from flange assemblies described herein. Flange assemblies may be positioned at various locations intermittently along a lengthwise direction of a glass transfer tube, and support assemblies may be positioned at other locations of a glass transfer tube where flange assemblies are not present.

[0167] An example support assembly 1678 with an internal opening having a width-to- height ratio of above 1 is illustrated in the schematic view of FIG. 16A. The support assembly 1678 also includes a glass transfer tube 1686, and this glass transfer tube 1686 may comprise platinum. In some embodiments, the glass transfer tube 1686 may consist solely of platinum. The glass transfer tube 1686 may extend between a stir chamber and a bowl to connect the stir chamber and the bowl, but glass transfer tubes connecting other portions of glass formation systems may be used.

[0168] The support assembly 1678 includes a top refractory section 1682, a bottom refractory section 1684, a first side section 1680A, and a second side section 1680B. These sections 1680A, 1680B, 1682, 1684 may serve as outer structures positioned outwardly from the glass transfer tube 1686. These outer structures also define an internal surface 1689A and an internal opening 1689 inside of the internal surface 1689A. The top refractory section 1682 and the bottom refractory section 1684 may both comprise a refractory material, and the sections 1682, 1684 may help to form a refractory cradle. The first side section 1680A and the second side section 1680B may each comprise a material (e.g., a metal) other than platinum. In other embodiments, the side sections 1680A, 1680B may comprise refractory material, and the sections 1680A, 1680B, 1682, 1684 may help to form a refractory cradle. However, side sections 1680A, 1680B may comprise different materials in other embodiments. The support assembly 1678 is configured to receive the glass transfer tube 1686 within the internal opening 1689.

[0169] In the support assembly 1678, the internal opening 1689 defines a height Dl l and a width D12. The height Dl l may be measured from the internal surface 1689A at the top refractory section 1682 to the internal surface 1689A at the bottom refractory section 1684. The width D 12 may be measured from an extreme tip at the internal surface 1689A of the first side section 1680A to an extreme tip at the second side section 1680B. The width D12 is larger than the height Dl l in the example of FIG. 16A. In some embodiments, the width D12 may be at least about 2.0 times larger than the height Dl l.SP24-215

[0170] The glass transfer tube 1686 is hollow and defines a middle opening 1690 therein. Molten glass may flow within the middle opening 1690 within the glass transfer tube 1686. Controlling the shape of the internal opening 1689 during the design process may allow the shape of the middle opening 1690 inside of the glass transfer tube 1686 to be better controlled when the assembly reaches an operating temperature.

[0171] Support tabs 1688 are positioned at the top refractory section 1682. The support tabs 1688 may be used in conjunction with glass transfer tubes having larger widths. One support tab 1688 is illustrated in greater detail in FIG. 16B. The top refractory section 1682 defines a first opening 1682A and a second opening 1682B, with the first opening 1682A being wider than the second opening 1682B. The support tab 1688 includes a first portion 1688A and a second portion 1688B. The first portion 1688A is larger than the width of the second portion 1688B. The width of the second portion 1688B is small enough to allow the second portion 1688B to extend through the second opening 1682B, but the width of the first portion 1688A is larger than the width of the second opening 1682B so that the first portion 1688A remains within the first opening 1682A. The second portion 1688B has a first end that is attached to the glass transfer tube 1686, and the second portion 1688B has a second end that is attached to the first portion 1688A.

[0172] A glass transfer assembly may get heated to an operating temperature so that the glass transfer assembly may be used to transfer molten glass. The operating temperature may be measured at a position proximate to glass transfer tube 1686 at the inlet of a glass transfer tube 1686 (e.g., around the inlet 115A illustrated in FIG. 1A), and this may typically be where the temperature is the largest for the glass transfer tube 1686. The operating temperature may be at between about 1300 degrees Celsius and about 1570 degrees Celsius, but other operating temperatures may be used. Where no support tabs are used, the top of the glass transfer tube 1686 may tend to sag during a heat up period before the operating temperature is reached, and this is because there is no internal glass pressure during this heat up period to hold the top of the glass transfer tube 1686 up. For example, without the support tabs positioned at the top refractory section 1682, the glass transfer tube 1686 above the middle opening 1690 may tend to buckle downwardly towards the center of the middle opening 1690. The support tabs may exert additional forces on the glass transfer tube to reduce buckling in the glass transfer tube. For example, support tabs may help to reduce elastic or plastic buckling due to loading prior to or during heat up, and support tabs may also help to reduce creep buckling deformation (e.g., from a side region) or creep sag deformation (e.g., from a top region) during or after heat up.SP24-215While the support tabs 1688 are positioned at the top refractory section 1682, support tabs 1688 may be positioned at other locations as well to reduce the amount of buckling that occurs. The support tabs 1688 may beneficially reduce buckling of the glass transfer tube 1686 at select locations. Support tabs 1688 may also be used to reduce buckling that may occur in the glass transfer tube 1686 when the glass transfer tube 1686 is heated to an operating temperature (e.g., at a left side or a right side of glass transfer tube 1686).

[0173] As illustrated in FIG. 16B, a space 1687 may be positioned between the glass transfer tube 1686 and the top refractory section 1682. This space 1687 may extend all the way around the glass transfer tube 1686 between the glass transfer tube 1686 and the sections 1680A, 1680B, 1682, 1684. In the embodiment illustrated in FIG. 16B, the glass transfer tube 1686 has not been heated up to an operating temperature. However, the space 1687 is beneficial to account for potentially different coefficients of thermal expansion between the glass transfer tube 1686 and other materials within the assembly (e.g., within the top refractory material). Once the operating temperature is reached, the glass transfer tube 1686 may expand outwardly to occupy some or all of the space 1687. Thus, the space 1687 may provide allowance for thermal expansion differences between the glass transfer tube 1686 and the surrounding sections. The design of the support tabs 1688 may account for the space 1687 to allow for expansion of the material within the glass transfer tube 1686.

[0174] However, support tabs may also require additional material to be used (e.g., metal). Additionally, the use of support tabs may add complexity to the design of the glass transfer assembly. For example, the top refractory section 1682 has openings 1682A, 1682B formed therein that are configured to receive the support tabs, and these openings 1682A, 1682B add additional complexity to the design and add manufacturing processes that must be performed to form the top refractory section 1682. Additionally, glass transfer tubes may be subjected to large stresses proximate to the support tabs 1688. Glass transfer tubes and support tabs 1688 may also be subjected to higher creep strains when subjected to high temperatures. Support tabs may also be difficult to implement where a design does not include a space (e.g., like space 1687) between a glass transfer tube and surrounding support material to allow for differential expansion. Thus, support tabs may not be used in all embodiments. Even where support tabs are not used, a glass transfer tube may be better supported when the glass transfer tube is shifted to a vertical geometry with a width-to-height ratio of less than 1 as discussed herein.

[0175] FIG. 17 is a schematic view illustrating an example support assembly 1785 with an internal opening 1789 having a width that is less than its height. A glass transfer tube (notSP24-215 shown) may be positioned within the internal opening 1789. A castable material 1794 may be positioned outwardly from the glass transfer tube, and the castable material 1794 may be positioned inwardly relative to a refractory cradle 1792. The castable material 1794 may define an internal surface 1789A that extends around the entire perimeter of the internal opening 1789, and the glass transfer tube may be received in the internal opening 1789 so that the glass transfer tube comes in contact with the castable material 1794 at the internal surface 1789A. The refractory cradle 1792 is positioned outwardly from the castable material 1794. The refractory cradle 1792 may be provided in one or more sections, and the refractory cradle 1792 comprises a refractory material. The castable material 1794 may provide close support to the glass transfer tube and may reduce the risk of leaks from the glass transfer tube when the glass transfer tube is received within the internal opening 1789.

[0176] The internal opening 1789 defines a height D 13 and a width D14. The height D 13 and the width D14 may be measured in a similar manner to other examples described herein. The height D13 may be measured from the uppermost point of the internal surface 1789 A of the castable material 1794 to the lowest point of the internal surface 1789A of the castable material 1794. The width D14 may be measured from the farthest point to the left on the internal surface 1789A of the castable material 1794 to the farthest point to the right on the internal surface 1789A of the castable material 1794.

[0177] The internal opening 1789 defines a width-to-height ratio, with this ratio being the width D 14 divided by the height D 13. The width-to-height ratio may be calculated in a similar manner for other embodiments. In FIG. 17, the height D13 is greater than the width D14 such that the width-to-height ratio is less than 1. In some embodiments, the width-to-height ratio may be between about 0.5 and about 0.9, between about 0.6 and about 0.8, between about 0.65 and about 0.75. In the illustrated embodiment, the width-to-height ratio is about 0.7. However, other width-to-height ratios may be used. At the optimal width-to-height ratio, the differential expansion between the glass transfer tube and surrounding support material (e.g., castable) is such that the support material provides slight compression to the glass transfer tube without causing buckling. This compression increases the friction forces between the glass transfer tube and the surrounding support material and reduces the overall top sag of the glass transfer tube. If the compressive force is too large, the compressive force may deform the glass transfer tube inwards and contribute to the overall buckling of the vertical sides and lead to faster top sag as illustrated in various examples in FIGS. 18A-18C and 19A-19C. By controlling theSP24-215 width-to-height ratio of the internal opening 1789, the shape of the glass transfer tube may be better controlled upon being heated to an operating temperature.

[0178] Modeling of various geometries for internal openings was done to investigate the time to collapse for each geometry. Time to collapse was defined as a rapid increase in the rate of sag of the top of the platinum. Where geometries were used with a typical horizontal geometry with the width-to-height ratio of above 1, the shape of the glass transfer tubes collapsed earlier than when vertical geometries were used with a width-to-height ratio of less than about 1. Modeling was done without using any support tabs. The modeling showed that the particular width-to-height ratio selected impacted the support provided for glass transfer tubes and the amount of deformation that occurs in glass transfer tubes. Selection of an appropriate width-to-height ratio also impacted the time to collapse and helped to reduce the risk of collapse. Results obtained for different width-to-height ratios are illustrated in FIGS. 18A-18C and 19A-19C.

[0179] FIG. 18A is a schematic view illustrating deformation within a glass transfer tube 1886A comprising platinum when a particular geometry for an internal opening 1889A is used. The support member 1899A defines an internal surface 1891 A defining an internal opening 1889A therein, and the glass transfer tube 1886A (which may comprise platinum) is positioned inside of the internal surface 1891 A and inside of this internal opening 1889A. The internal surface 1891 A defines a bottom rounded portion 1801 A, a first side portion 1803 A, a top rounded portion 1805 A, and a second side portion 1807A. The top rounded portion 1805 A defines a radius Rl, and the radius R1 remains constant for the entirety of the top rounded portion 1805A. The top rounded portion 1805A defines a half-circle. The bottom rounded portion 1801 A defines a radius R2, and the radius R2 remains constant for the entirety of the bottom rounded portion 1801 A. Where shapes for top rounded portions and bottom rounded portions are discussed herein, these may be the shapes before heat up, during heat up, and / or when molten glass is actively flowing. In some embodiments, the top rounded portion 1805A and the bottom rounded portion 1801 A may not possess a constant radius of curvature. The bottom rounded portion 1801 A defines a half-circle. The first side portion 1803A connects to both the bottom rounded portion 1801 A and the top rounded portion 1805 A on the left side, and the second side portion 1807A connects to both the bottom rounded portion 1801 A and the top rounded portion 1805A on the right side. The side portions 1803A, 1807A are both flat and / or planar in shape. However, in some embodiments, the side portions 1803 A, 1807A maySP24-215 be rounded (e.g., parabolic curvature, constant curvature, etc.) to provide the internal opening 1889A with an elliptical shape or an oval shape.

[0180] In the support member 1899A of FIG. 18A, the internal opening 1889A defines a height D15 and a width DI 6. The width-to-height ratio (the width D16 divided by the height D15) is about 0.6 for the internal opening 1889A. When this width-to-height ratio is used, the glass transfer tube 1886A may deform as illustrated when heated to an operating temperature. This operating temperature may be between about 1300 degrees Celsius and about 1570 degrees Celsius, but other operating temperatures may be used. The glass transfer tube 1886A may remain positioned proximate to the bottom rounded portion 1801 A, and the glass transfer tube 1886A may often deform or buckle proximate to the side portions 1803A, 1807A. Relative to the glass transfer tubes 1886B, 1886C of FIGS. 18B and FIGS. 18C, the glass transfer tube 1886A of FIG. 18A experiences the least buckling proximate to the side portions 1803 A, 1807A.

[0181] The buckling ofthe glass transfer tube 1886A proximate to the side portions 1803A, 1807A causes the glass transfer tube 1886A to sag down relative to the internal surface 1891A at the top rounded portion 1805A. The glass transfer tube 1886A of FIG. 18A sags less proximate to the top rounded portion 1805A than the glass transfer tubes 1886B, 1886C of FIGS. 18B and 18C.

[0182] FIG. 18B is a schematic view illustrating deformation within a glass transfer tube 1886B comprising platinum when a particular geometry for an internal opening 1889B is used. The support member 1899B defines an internal surface 1891B defining an internal opening 1889B therein, and the glass transfer tube 1886B (which may comprise platinum) is positioned inside of the internal surface 189 IB and inside of this internal opening 1889B. The internal surface 189 IB defines a bottom rounded portion 180 IB, a first side portion 1803B, a top rounded portion 1805B, and a second side portion 1807B. The top rounded portion 1805B defines a radius R3, and the radius R3 remains constant for the entirety of the top rounded portion 1805B. The top rounded portion 1805B defines a half-circle.

[0183] The bottom rounded portion 180 IB defines a radius R4, and the radius R4 remains constant for the entirety of the bottom rounded portion 1801B. However, in other embodiments, the top rounded portion 1805B and the bottom rounded portion 180 IB may not possess a constant radius of curvature. The bottom rounded portion 1801B defines a halfcircle. The side portion 1803B connects to both the bottom rounded portion 180 IB and the top rounded portion 1805B on the left side, and the side portion 1807B connects to both the bottomSP24-215 rounded portion 180 IB and the top rounded portion 1805B on the right side. The side portions 1803B, 1807B are both flat and / or planar in shape. However, in some embodiments, the side portions 1803B, 1807B may be rounded (e.g., parabolic curvature, constant curvature, etc.) to provide the internal opening 1889B with an elliptical shape.

[0184] In the support member 1899B of FIG. 18B, the internal opening 1889B defines a height D17 and a width DI 8. The width-to-height ratio (the width D18 divided by the height D17) is about 0.5. When this width-to-height ratio is used, the glass transfer tube 1886B may deform as illustrated when heated to an operating temperature. The glass transfer tube 1886B may remain positioned proximate to the bottom rounded portion 180 IB, and the glass transfer tube 1886B may often deform or buckle proximate to the side portions 1803B, 1807B. The glass transfer tube 1886B of FIG. 18B experiences more buckling at the sides relative to the glass transfer tube 1886A of FIG. 18A, but the glass transfer tube 1886B of FIG. 18B experiences less buckling at the sides relative to the glass transfer tube 1886C of FIG. 18C.

[0185] The buckling of the glass transfer tube 1886B proximate to the side portions 1803B, 1807B leads to the glass transfer tube 1886B sagging down relative to the internal surface 189 IB at the top rounded portion 1805B. The glass transfer tube 1886B ofFIG. 18B sags more proximate to the top rounded portion 1805B than the glass transfer tube 1886A of FIG. 18A, but the glass transfer tube 1886B of FIG. 18B sags less proximate to the top rounded portion 1805B of the glass transfer tube 1886B than the glass transfer tube 1886C of FIG. 18C.

[0186] FIG. 18C is a schematic view illustrating deformation within a glass transfer tube 1886C comprising platinum when a particular geometry for an internal opening 1889C is used. A support member 1899C defines an internal surface 1891C defining an internal opening 1889C therein, and the glass transfer tube 1886C (which may comprise platinum) is positioned inside of the internal surface 1891C and inside of this internal opening 1889C. The internal surface 1891C defines a bottom rounded portion 1801C, a first side portion 1803C, a top rounded portion 1805C, and a second side portion 1807C. The top rounded portion 1805C defines a radius R5, and the radius R5 remains constant for the entirety of the top rounded portion 1805C. The top rounded portion 1805C defines a half-circle. The bottom rounded portion 1801C defines a radius R6, and the radius R6 remains constant for the entirety of the bottom rounded portion 1801C. However, in other embodiments, the top rounded portion 1805C and the bottom rounded portion 1801C may not possess a constant radius of curvature. The bottom rounded portion 1801C defines a half-circle. The first side portion 1803C connects to both the bottom rounded portion 1801 C and the top rounded portion 1805C on the left side,SP24-215 and the second side portion 1807C connects to both the bottom rounded portion 1801C and the top rounded portion 1805C on the right side. The side portions 1803C, 1807C are both flat and / or planar in shape. However, in some embodiments, the side portions 1803C, 1807C may be rounded (e.g., parabolic curvature, constant curvature, etc.) to provide the internal opening 1889C with an elliptical shape.

[0187] In the support member 1899C of FIG. 18C, the internal opening 1889C defines a height D19 and a width D20. The width-to-height ratio (the width D20 divided by the height D19) is about 0.43. When this width-to-height ratio is used, the glass transfer tube 1886C may deform as illustrated when heated to an operating temperature. The glass transfer tube 1886C may remain positioned proximate to the bottom rounded portion 1801C, and the glass transfer tube 1886C may often deform or buckle proximate to the side portions 1803C, 1807C. The glass transfer tube 1886C of FIG. 18C experiences more buckling at the sides relative to the glass transfer tube 1886A of FIG. 18A, but the glass transfer tube 1886C of FIG. 18C experiences less buckling at the sides relative to the glass transfer tube 1886C of FIG. 18C.

[0188] The buckling of the glass transfer tube 1886C proximate to the side portions 1803C, 1807C may lead to the glass transfer tube 1886C sagging down relative to the internal surface 1891C atthe top rounded portion 1805C. The glass transfer tube 1886C ofFIG. I8C sags more proximate to the top rounded portion 1805C than the glass transfer tubes 1886A, 1886B of FIG. 18A and l8B. In FIGS. 18A-18C, the widths DI 6, DI 8, D20 are all equal, and the width- to-height ratios were adjusted by using different values for the heights D15, D17, D19.

[0189] FIG. 19A is a schematic view illustrating deformation within a glass transfer tube 1986A comprising platinum when another geometry for an internal opening 1989A is used. The support member 1999A defines an internal surface 1991 A defining an internal opening 1989A therein, and the glass transfer tube 1986A (which may comprise platinum) is positioned inside of the internal surface 1991 A and inside of this internal opening 1989A. The internal surface 1991 A defines a bottom rounded portion 1901 A, a first side portion 1903 A, a top rounded portion 1905A, and a second side portion 1907A. The top rounded portion 1905A defines a radius R7, and the radius R7 remains constant for the entirety of the top rounded portion 1905A. The top rounded portion 1905A defines a half-circle. The bottom rounded portion 1901 A defines a radius R8, and the radius R8 remains constant for the entirety of the bottom rounded portion 1901 A. However, in other embodiments, the top rounded portion 1905 A and the bottom rounded portion 1901 A may not possess a constant radius of curvature. The bottom rounded portion 1901A defines a half-circle. The side portion 1903A connects toSP24-215 both the bottom rounded portion 1901 A and the top rounded portion 1905 A on the left side, and the second side portion 1907A connects to both the bottom rounded portion 1901 A and the top rounded portion 1905 A on the right side. The side portions 1903 A, 1907A are both flat and / or planar in shape. However, in some embodiments, the side portions 1903 A, 1907A may be rounded (e.g., parabolic curvature, constant curvature, etc.) to provide the internal opening 1989A with an elliptical shape.

[0190] In the support member 1999A of FIG. 19A, the internal opening 1989A defines a height D21 and a width D22. The width-to-height ratio (the width D22 divided by the height D21) is about 0.67. When this width-to-height ratio is used, the glass transfer tube 1986A may deform as illustrated when heated to an operating temperature. This operating temperature may be between about 1300 degrees Celsius and about 1570 degrees Celsius, but other operating temperatures may be used. The glass transfer tube 1986A may remain positioned proximate to the bottom rounded portion 1901 A, and the glass transfer tube 1986A may often deform or buckle proximate to the first side portion 1903 A and / or the second side portion 1907A. In the embodiment illustrated in FIG. 19A, the glass transfer tube 1986A experiences buckling proximate to the side portion 1903 A and experiences very little buckling proximate to the second side portion 1907A, but the amount of buckling may be similar at each of the sides in other embodiments. Relative to the glass transfer tubes 1986B, 1986C of FIGS. 19B and FIGS. 19C, the glass transfer tube 1986A of FIG. 19A experiences the least buckling proximate to the side portions 1903 A, 1907A.

[0191] The buckling of the glass transfer tube 1986A proximate to the side portion 1903 A leads to the glass transfer tube 1986A sagging down relative to the internal surface 1991A at the top rounded portion 1905 A. The glass transfer tube 1986A of FIG. 19A sags more proximate to the top rounded portion 1905 A than the glass transfer tubes 1986B, 1986C of FIGS. 19B and 19C.

[0192] FIG. 19B is a schematic view illustrating deformation within a glass transfer tube 1986B comprising platinum when a particular geometry for an internal opening 1989B is used. The support member 1999B defines an internal surface 199 IB defining the internal opening 1989B therein, and the glass transfer tube 1986B (which may comprise platinum) is positioned inside of the internal surface 199 IB and inside of this internal opening 1989B. The internal surface 1991B defines a bottom rounded portion 1901B, a first side portion 1903B, a top rounded portion 1905B, and a second side portion 1907B. The top rounded portion 1905B defines a radius R9, and the radius R9 remains constant for the entirety of the top roundedSP24-215 portion 1905B. The top rounded portion 1905B defines a half-circle. The bottom rounded portion 1901B defines a radius RIO, and the radius RIO remains constant for the entirety of the bottom rounded portion 190 IB. However, in other embodiments, the top rounded portion 1905B and the bottom rounded portion 1901B may not possess a constant radius of curvature. The bottom rounded portion 1901B defines a half-circle. The side portion 1903B connects to both the bottom rounded portion 1901B and the top rounded portion 1905B on the left side, and the side portion 1907B connects to both the bottom rounded portion 190 IB and the top rounded portion 1905B on the right side. The side portions 1903B, 1907B are both flat and / or planar in shape. However, in some embodiments, the side portions 1903B, 1907B may be rounded (e.g., parabolic curvature, constant curvature, etc.) to provide the internal opening 1989B with an elliptical shape.

[0193] In the support member 1999B of FIG. 19B, the internal opening 1989B defines a height D23 and a width D24. The width-to-height ratio (the width D24 divided by the height D23) is about 0.75. When this width-to-height ratio is used, the glass transfer tube 1986B may deform as illustrated when heated to an operating temperature. The glass transfer tube 1986B may remain positioned proximate to the bottom rounded portion 190 IB, and the glass transfer tube 1986B may often deform or buckle proximate to the side portion 1903B and / or the side portion 1907B. In the embodiment illustrated in FIG. 19B, the glass transfer tube 1986B experiences some buckling proximate to the side portion 1903B and experiences little buckling proximate to the side portion 1907B, but the amount of buckling may be similar at each of the sides in other embodiments. The glass transfer tube 1986B of FIG. 19B experiences the least buckling proximate to the side portions relative to the glass transfer tube 1986A of FIG. 19A and the glass transfer tube 1986C of FIG. 19C. Additionally, the glass transfer tube 1986B of FIG. 19B sags less proximate to the top rounded portion 1905B relative to the glass transfer tubes 1986A, 1986C ofFIGS. 19A and 19C.

[0194] FIG. 19C is a schematic view illustrating deformation within a glass transfer tube 1986C comprising platinum when a particular geometry for an internal opening 1989C is used. The support member 1999C defines an internal surface 1991C defining the internal opening 1989C therein, and the glass transfer tube 1986C (which may comprise platinum) is positioned inside of the internal surface 1991C and inside of this internal opening 1989C. The internal surface 1991C defines a bottom rounded portion 1901C, a first side portion 1903C, a top rounded portion 1905C, and a second side portion 1907C. The top rounded portion 1905C defines a radius R11, and the radius R11 remains constant for the entirety of the top roundedSP24-215 portion 1905C. The top rounded portion 1905C defines a half-circle. The bottom rounded portion 1901C defines a radius R12, and the radius R12 remains constant for the entirety of the bottom rounded portion 1901C. However, in other embodiments, the top rounded portion 1905C and the bottom rounded portion 1901C may not possess a constant radius of curvature. The bottom rounded portion 1901C defines a half-circle. The first side portion 1903C connects to both the bottom rounded portion 1901C and the top rounded portion 1905C on the left side, and the second side portion 1907C connects to both the bottom rounded portion 1901C and the top rounded portion 1905C on the right side. The side portions 1903C, 1907C are both flat and / or planar in shape. However, in some embodiments, the side portions 1903C, 1907C may be rounded (e.g., parabolic curvature, constant curvature, etc.) to provide the internal opening 1989C with an elliptical shape.

[0195] In the support member 1999C of FIG. 19C, the internal opening 1989C defines a height D25 and a width D26. The width-to-height ratio (the width D26 divided by the height D25) is about 0.83. When this width-to-height ratio is used, the glass transfer tube 1986C may deform as illustrated when heated to an operating temperature. The glass transfer tube 1986C may remain positioned proximate to the bottom rounded portion 1901C, and the glass transfer tube 1986C may often deform or buckle proximate to the first side portion 1903C and / or the second side portion 1907C. In the embodiment illustrated in FIG. 19C, the glass transfer tube 1986C experiences a similar amount of buckling proximate to both the first side portion 1903C and the second side portion 1907C, but the amount of buckling may be different at these sides in other embodiments. The glass transfer tube 1986C of FIG. 19C experiences less buckling overall relative to the glass transfer tube 1986A of FIG. 19A, but the glass transfer tube 1986C of FIG. 19C experiences more buckling relative to the glass transfer tube 1986B of FIG. 19B.

[0196] Additionally, the glass transfer tube 1986C of FIG. 19C sags less proximate to the top rounded portion 1905C relative to the glass transfer tube 1986A of FIG. 19A, but the glass transfertube 1986C ofFIG. 19C sags more proximate to the top rounded portion 1905C relative to the glass transfer tube 1986B of FIG. 19B. In FIGS. 19A-19C, the heights D21, D23, D25 are all equal, and the width-to-height ratios were adjusted by using different values for the widths D22, D24, D26.

[0197] In addition to two-dimensional modeling that was done to evaluate and select potential width-to-height ratios, three-dimensional modeling was done using these width-to- height ratios to add in the effects of the other components that the glass transfer tubes and support assemblies would interact with (e.g., flange assemblies). This modeling correlatedSP24-215 well to the two-dimensional modeling and showed little sag of the top of the glass transfer tube, as well as minimal buckling of the vertical sides of the glass transfer tube.

[0198] Methods for using flange assemblies to heat molten glass are also contemplated, and one example method 2000 is illustrated in the flow chart of FIG. 20. At operation 2002, a glass transfer tube is provided that is hollow. The glass transfer tube may be configured to allow molten glass to flow through the interior volume of the glass transfer tube. In some embodiments, the glass transfer tube may connect a stir-chamber and a bowl in a glass formation system.

[0199] At operation 2004, a flange assembly is provided. The flange assembly may comprise an inner structure and an outer structure. The inner structure may define a central opening therein, and the inner structure may be configured to receive the glass transfer tube within the central opening so that the inner structure is in contact with the glass transfer tube. The outer structure is primarily comprised of material other than platinum, and the outer structure is directly attached to the inner structure. The flange assembly may be similar to one of the flange assemblies described herein.

[0200] At operation 2006, a support assembly may be provided. The support assembly may include an inner surface defining an internal opening therein. The support assembly may include a castable material, and the inner surface may be defined at the castable material in some embodiments. The internal opening may define a height and a width, and the height may be greater than the width. A width-to-height ratio for the internal opening may be less than about 1, between about 0.5 and about 0.9, between about 0.6 and about 0.8, between about 0.65 and about 0.75, or the width-to-height ratio may be about 0.7.

[0201] At operation 2008, the glass transfer tube is positioned relative to the support assembly. The glass transfer tube may be positioned within the internal opening defined by the inner surface so that the inner surface of the support assembly is in contact with the glass transfer tube.

[0202] At operation 2010, the glass transfer tube is positioned within the central opening of the inner structure of the flange assembly so that the inner structure is in contact with the glass transfer tube. In some embodiments, the inner structure may be in contact with or attached to the glass transfer tube all the way around a cross-sectional perimeter of the glass transfer tube through welding or other attachment approaches.

[0203] At operation 2012, the outer structure of the flange assembly is connected to an electrical power source.SP24-215

[0204] At operation 2014, molten glass is caused to flow through an internal volume of the glass transfer tube.

[0205] At operation 2016, the electrical power source is activated. This may result in electrical current being conducted through the outer structure, through the inner structure, and through the glass transfer tube so that the glass transfer tube is heated and so that this heat is transferred at least partially to the molten glass. Once the electrical power source is activated and electrical current is conducted through the flange assembly, the maximum electrical current density within the inner structure may be limited relative to the minimum electrical current density within the inner structure. In some embodiments, the maximum electrical current density within the inner structure may be no more than 1.9 times the minimum electrical current density within the inner structure, no more than 1.75 times the minimum electrical current density within the inner structure, no more than 1.65 times the minimum electrical current density within the inner structure, or no more than 1.48 times the minimum electrical current density within the inner structure.

[0206] The method 2000 is merely exemplary, and the method 2000 may be modified in various ways. For example, additional operations may be added to the method 2000, and certain operations may be omitted from the method 2000. Additionally, the operations of method 2000 may be performed in any order, and operations may be performed simultaneously in some embodiments.CONCLUSION

[0207] Many modifications and other embodiments set forth herein will come to mind to one skilled in the art to which these embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the invention. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it should be appreciated that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the invention. In this regard, for example, different combinations of elements and / or functions than those explicitly described above are also contemplated within the scope of the invention. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

SP24-215WHAT IS CLAIMED IS:

1. A glass transfer system for heating molten glass, the glass transfer system comprising: a glass transfer tube configured to allow molten glass to flow within an internal volume of the glass transfer tube; and a support assembly having an inner surface defining an internal opening therein configured to receive the glass transfer tube, wherein the internal opening defines a height and a width, wherein the height is greater than the width, and wherein the support assembly is configured to receive the glass transfer tube within the internal opening.

2. The glass transfer system of claim 1, wherein a width-to-height ratio is equal to the width divided by the height, wherein the width-to-height ratio is between about 0.5 and about 0.9.

3. The glass transfer system of claim 2, wherein the width-to-height ratio is between about 0.6 and about 0.8.

4. The glass transfer system of claim 3, wherein the width-to-height ratio is between about 0.65 and about 0.75.

5. The glass transfer system of any of claims 1-4, wherein the glass transfer tube comprises platinum.

6. The glass transfer system of any of claims 1-5, wherein the support assembly comprises a refractory cradle positioned outwardly relative to the internal opening of the support assembly, and wherein the refractory cradle comprises a refractory material.

7. The glass transfer system of claim 6, wherein the support assembly comprises a castable material positioned outwardly relative to the internal opening of the support assembly, and wherein the castable material is positioned inwardly relative to the refractory cradle.SP24-2158. The glass transfer system of claim 1, further comprising: a stir chamber; and a bowl, wherein the glass transfer tube extends between the stir chamber and the bowl.

9. The glass transfer system of any of claims 1-8, wherein the glass transfer tube defines an inlet and an outlet, wherein the glass transfer system is configured to reach an inlet temperature at the inlet of the glass transfer tube, wherein the inlet temperature is at least about 1300 degrees Celsius.

10. The glass transfer system of claim 9, wherein the inlet temperature is between about 1300 degrees Celsius and about 1570 degrees Celsius.

11. The glass transfer system of any of claims 1-10, wherein the internal surface of the support assembly defines a top rounded portion, a bottom rounded portion, and two planar side surfaces.

12. The glass transfer system of claim 11, wherein a radius of curvature at the top rounded portion and a radius of curvature at the bottom rounded portion are constant.

13. The glass transfer system of any of claims 1-12, wherein the support assembly further comprises a support tab, wherein a first end of the support tab is attached to the glass transfer tube, and wherein the support tab is configured to apply a force to the glass transfer tube to reduce elastic buckling, plastic buckling, creep buckling, or creep sag deformation at the glass transfer tube.

14. A support assembly for a glass transfer tube, the support assembly comprising: at least one support section, wherein the at least one support section comprises a refractory cradle comprising a refractory material, wherein the at least one support section comprises an internal surface defining an internal opening therein, wherein the internal opening is configured to receive the glass transfer tube, wherein the internal opening has a height and a width, wherein the height is greater than the width, and wherein the support assembly is configured to receive the glassSP24-215 transfer tube within the internal opening so that the support assembly contacts the glass transfer tube.

15. The support assembly of claim 14, wherein a width-to-height ratio is equal to the width divided by the height, and wherein the width-to-height ratio is between about 0.5 and about 0.9.

16. The support assembly of claim 15, wherein the width-to-height ratio is between about 0.6 and about 0.8.

17. The support assembly of claim 16, wherein the width-to-height ratio is between about 0.65 and about 0.75.

18. The support assembly of any of claims 14-17, wherein the at least one support section comprises a castable material positioned outwardly relative to the internal opening, and wherein the castable material is positioned inwardly relative to the refractory cradle.

19. The support assembly of claim 18, wherein the castable material is positioned adjacent to the internal opening such that the castable material forms the internal surface.

20. The support assembly of any of claims 14-19, wherein the internal surface defines a top rounded portion, a bottom rounded portion, and two planar side surfaces.

21. The support assembly of claim 20, wherein a radius of curvature at the top rounded portion and the bottom rounded portion is constant.

22. The support assembly of any of claims 14-19, further comprising: a support tab, wherein a first end of the support tab is attached to the glass transfer tube, and wherein the support tab is configured to apply a force to the glass transfer tube to reduce buckling at the glass transfer tube.SP24-21523. The support assembly of claim 22, wherein the internal opening defines a top rounded portion, a bottom rounded portion, and two planar side surfaces, and wherein the support tab is positioned proximate to the top rounded portion or one of the two planar side surfaces.

24. A method of using a glass transfer system for heating molten glass, the method comprising: positioning a glass transfer tube relative to a support assembly, the support assembly comprising an internal surface defining an internal opening therein, wherein the glass transfer tube is positioned within the internal opening so that the glass transfer tube is in contact with the support assembly, wherein the internal opening defines a height and a width, and wherein the height is greater than the width; and causing molten glass to flow through an internal volume of the glass transfer tube.

25. The method of claim 24, wherein a width-to-height ratio is equal to the width divided by the height, and wherein the width-to-height ratio is between about 0.65 and about 0.75.

Images