Glass manufacturing apparatus with electrical flanges and method of joining flanges

Abstract

A glass manufacturing apparatus includes a conduit with an electrical flange attached to the conduit, the electrical flange having a first ring formed from a first metal and a second ring inside the first ring, attached to the conduit, and formed from a second metal different from the first metal. The second ring includes a first portion, a second portion, and a third portion joining the first portion to the second portion and configured such that a plane of the first portion is spaced apart from a plane of the second portion, and wherein an angle of a linear part of the third portion forms an angle with the plane of the first portion in a range from about 115 degrees to about 125 degrees. A method of joining subsystems of a glass manufacturing apparatus is also disclosed.

Description

GLASS MANUFACTURING APPARATUS WITH ELECTRICAL FLANGES AND METHOD OF JOINING FLANGESBACKGROUNDCROSS-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 / 677062 filed on July 30, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates to an apparatus for forming a glass article, and more particularly electrical flanges configured to mitigate against buckling and improve sealing between adjacent electrical flanges.TECHNICAL BACKGROUND

[0003] It is known to heat metallic vessels, particularly metallic vessels used in the containment and delivery of molten glass, for example delivery of molten glass to a forming apparatus, by delivering an electric current to the metallic vessel through electrical flanges attached to and in electrical communication with the metallic vessel. The electrical current heats the metallic vessel by Joule heating, which in turn heats the molten glass therein. Such Joule heating can, for example, be used to control a viscosity of the molten glass, such as in preparation for forming.

[0004] Electrical flanges may be used to form a seal between adjacent subassemblies of a glass manufacturing apparatus, for example adjacent vessels or conduits thereof. Buckling of individual electrical flanges, for example due to temperature differentials across the electrical flange, may prevent adequate sealing between adjacent electrical flanges and lead to entrapment of gases, including oxygen, in gaps between the electrical flanges. Erosion and oxidation of the electrical flanges due to such trapped gases may cause metallic particle contamination of molten glass flowing through the manufacturing subassemblies.

[0005] What is needed is an improved electrical flange capable of providing enhanced sealing with an adjacent electrical flange.SUMMARY

[0006] In a first aspect, a glass manufacturing apparatus is disclosed comprising a conduit configured to convey molten glass, an electrical flange comprising a body portion and an electrode portion extending away from the body portion, the body portion comprising a first ring comprising a first metal, a second ring comprising a second metal different than the first metal, the second ring comprising a first portion defining a first plane, a second portion attached to the conduit and defining a second plane, and a third portion joining the first portion and the second portion, and wherein the second plane is spaced apart from the first plane.

[0007] In a second aspect, the third portion of the first aspect may comprise a first arc and a second arc in a cross-section of the second ring, the second arc facing a direction opposite a direction of the first arc.

[0008] In a third aspect, the third portion of the second aspect may comprise a linear portion between the first arc and the second arc in the cross-section of the second ring, and an angle of the linear portion relative to the first plane is in a range from about 115 degrees to about 125 degrees.

[0009] In a fourth aspect, a width of the second portion of any one of the first aspect to the third aspect may be equal to or greater than about 5 cm.

[0010] In a fifth aspect, the first plane of any one of the first aspect to the fourth aspect may be parallel with the second plane.

[0011] In a sixth aspect, the first ring of the fifth aspect may define a third plane, and the first plane may not be parallel with the third plane.

[0012] In a seventh aspect, the first plane of any one of the first aspect to the sixth aspect may be spaced apart from the second plane by a distance in a range from about 0.6 cm to about 1.9 cm.

[0013] In an eighth aspect, the first ring of any one of the first aspect to the seventh aspect may comprise nickel.

[0014] In a ninth aspect, the second ring of any one of the first aspect to the eighth aspect may comprise platinum.

[0015] In a tenth aspect, the glass manufacturing apparatus of any one of the first aspect to the ninth aspect may further comprise a second electrical flange disposed on a second conduit, the second conduit arranged such that the second electrical flange is opposite to and in contact with the first electrical flange.

[0016] In an eleventh aspect, the glass manufacturing apparatus of the tenth aspect may comprise a refractory melting vessel and the second conduit may extend from the refractory melting vessel.

[0017] In a twelfth aspect, the second electrical flange of the tenth aspect may comprise a second body portion and a second electrode portion extending away from the second body portion, the second body portion comprising a first ring comprising the first metal, and a second ring comprising the second metal, the second ring of the second body portion comprising a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion of the second ring of the second body portion and wherein the second plane of the second portion of the second ring of the second body portion is spaced apart from the first plane of the second portion of the second ring of the first body portion.

[0018] In a thirteenth aspect, the second portion of the second ring of the second body portion of the twelfth aspect may extend outward toward the first electrical flange and the second portion of the second ring of the first body portion may extend outward toward the second electrical flange.

[0019] In a fourteenth aspect, the first ring of the first electrical flange of the twelfth aspect may be spaced apart from the first ring of the second electrical flange by a distance equal to or less than about 2.5 cm.

[0020] In a fifteenth aspect, at least the first portion of the second ring of the first electrical flange of any one of the first aspect to the fourteenth aspect may be coated with a stabilized zirconia coating.

[0021] In a sixteenth aspect, a method of joining subsystems of a glass manufacturing apparatus is disclosed, comprising preheating a first subsystem of the glass manufacturing system to a first temperature in a range from about 1400°C to about 1700°C, the first subsystem comprising a first conduit, the first conduit comprising a first electrical flange disposed on a distal end of the first conduit, the first electrical flange comprising a first ring comprising a first metal, and a second ring attached to the first ring and the first conduit and comprising a second metal different from the first metal, the second ring comprising a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion, and the second plane is displaced from the first plane.

[0022] The method may further comprise preheating a second subsystem of the glass manufacturing apparatus to a second temperature in a range from about 1400°C to about1700°C, the second subsystem comprising a second conduit, the second conduit comprising a second electrical flange attached to a distal end of the second conduit, the second electrical flange comprising a first ring comprising the first metal, a second ring attached to the first ring and the second conduit and comprising the second metal, the second ring comprising a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion of the second ring of the second electrical flange, and the second plane is spaced apart from the first plane.

[0023] The method may still further disclose moving at least one of the preheated first subsystem or the preheated second subsystem such that the second ring of the first electrical flange contacts the second ring of the second electrical flange; and wherein a maximum deformation of the second portion of the second ring of the first electrical flange or the second portion of the second ring of the second electrical flange, after the preheating the first subsystem and the second subsystem, does not exceed 13 mm.

[0024] In a seventeenth aspect, the third portion of the second ring of the first electrical flange of the sixteenth aspect may comprise a first arc and a second arc in a cross-section of the second ring of the first electrical flange, and wherein the second arc faces a direction opposite a direction of the first arc.

[0025] In an eighteenth aspect, the third portion of the second ring of the first electrical flange of the sixteenth aspect may comprise a linear portion between the first arc and the second arc in the cross-section of the second ring of the first electrical flange, and an angle of the linear portion relative to the first plane of the first portion of the second ring of the first electrical flange is in a range from about 115 degrees to about 125 degrees.

[0026] In a nineteenth aspect, a width of the second portion of the second ring of the first electrical flange of any one of the sixteenth aspect to the eighteenth aspect may be equal to or greater than 5 cm.

[0027] In a twentieth aspect, the first ring of the first electrical flange of any one of the sixteenth aspect to the nineteenth aspect may define a third plane, and the first plane of the first portion of the first electrical flange may not parallel with the third plane of the first ring of the first electrical flange.

[0028] In a twenty first aspect, after the moving of any one of the sixteenth aspect to the twentieth aspect, at least a portion of the first electrical flange may be bonded to at least a portion of the second electrical flange.

[0029] In a twenty second aspect, the at least a portion of the first electrical flange of the twenty first aspect may be diffusion bonded to the at least a portion of the second electrical flange.

[0030] In a twenty third aspect, the second portion of the second ring of the first electrical flange of the twenty first aspect may be bonded to the second portion of the second ring of the second electrical flange.

[0031] In a twenty fourth aspect, the third portion of the second ring of the first electrical flange may comprise a strain relief feature. The third portion of the second ring of the second electrical flange may comprise a strain relief feature. The strain relieve feature may comprise a curved and be shaped like an “S” curve or comprise an ogee shape.

[0032] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description that follows, and in part will be clear to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0033] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the embodiments disclosed herein. The accompanying drawings are included to provide further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description explain the principles and operations thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic view of an exemplary glass manufacturing apparatus according to embodiments of the present disclosure;

[0035] FIG. 2 is a front view of an example electrical flange according to embodiment of the present disclosure;

[0036] FIG. 3 is a front view of another example electrical flange according to embodiments of the present disclosure;

[0037] FIG. 4 is a cross-sectional side view of a portion of a glass manufacturing apparatus showing mating between two subassemblies of the glass manufacturing apparatus via adjacent electrical flanges;

[0038] FIG. 5 is a cross-sectional edge view of another electrical flange according to embodiments of the present disclosure;

[0039] FIG. 6 is a cross-sectional edge view of a portion of the electrical flange of FIG. 5;

[0040] FIG. 7 is a cross-sectional edge view of still another electrical flange according to the present disclosure; and

[0041] FIG. 8 is a cross-sectional edge view of two conduits, each conduit comprising an electrical flange disposed on an end of the respective conduit, and the electrical flanges are in an adjacent and proximate relationship such that a sealing area between the second rings of the electrical flanges is visible.DETAILED DESCRIPTION

[0042] Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0043] As used herein, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “component” includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0044] The terms “substantially” and “about” may be used herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also used herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issuer. Thus, amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In particular, the terms “substantial,” “substantially,” and variations thereof as used herein denote that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially” may denote values within about 10% of each other, such as within about 5% of each other, within about 2% of each other, or within about 1% of each other.

[0045] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value to the other particular value. Similarly, when values are expressed asapproximations by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0046] For brevity, ranges of values disclosed herein, including compositional ranges or attribute (performance) ranges, or series of ranges, may be appended by the phrase “including all ranges and subranges therebetween,” which is to be interpreted as including whole number or decimal subranges as though explicitly presented. Thus, by way of example, a range between 6 and 8 (units omitted) implicitly includes a subrange between 6.4 and 8, or a subrange between 6 and 7.2, or a subrange between 6 and 7, and so forth. Additionally, a series of ranges, such as “in a range from 6 to 11 or in a range from 6 to 8” implicitly includes a range from 7 to 10, or subranges therebetween, such as 7.2 to 10.4, as though explicitly presented, provided the range does not exceed the minimum or maximum endpoints of the explicitly presented range or series of ranges. Thus, for example, “in a range from 6 to 11 or in a range from 6 to 8” has as endpoints 6 and 11.

[0047] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification.

[0048] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0049] The word “exemplary,” “example,” or various forms thereof are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” or as an “example” should not be construed as preferred or advantageous over other aspects or designs. Furthermore, examples are provided solely for purposes of clarity and understanding and are not meant to limit or restrict the disclosed subject matter or relevant portions of this disclosure in any manner.

[0050] As used herein, the terms “comprising” and “including”, and variations thereof, shall be construed as synonymous and open-ended, unless otherwise indicated. A list of elementsfollowing the transitional phrases comprising or including is a non-exclusive list, such that elements in addition to those specifically recited in the list may also be present.

[0051] As used herein, the term “electrically connected,” “electrically connecting,” and variations thereof, mean connected by way of an electrical conductor not including a molten material (e.g., molten glass). A first element electrically connected to a second element can include additional elements between the first element and the second element such that the additional elements are also electrically connected to the first element and the second element. That is, a first element electrically connected to a second element is not to be construed as precluding the presence of additional conducting elements in the connection. Typically, such electrical conductors can comprise metallic wiring or cabling, buss bars, and the like, but are not limited thereto. The electrical connection may further include other components, including but not limited to electrical connectors (e.g., plugs, tabs, lugs, bolts, etc.) that facilitate connection between components, electrical control devices such as electrical current and / or voltage controllers, electrical current and / or voltage measurement devices, and the like.

[0052] As used herein, “refractory” refers to non-metallic materials having chemical and physical properties making them applicable for structures, or as components of systems, that are exposed to environments above 538°C.

[0053] Shown in FIG. 1 is an example glass manufacturing apparatus 10. Glass manufacturing apparatus 10 can comprise a glass melting furnace 12 including a melting vessel 14. In addition to melting vessel 14, glass melting furnace 12 may optionally include one or more additional components such as heating elements (e.g., combustion burners and / or electrodes) configured to heat raw material and convert the raw material into molten glass. For example, melting vessel 14 may be an electrically-boosted melting vessel, wherein energy is added to the raw material through both combustion burners and by direct heating, wherein an electrical current is passed through the raw material, the electrical current thereby adding energy via Joule heating of the raw material.

[0054] In embodiments, glass melting furnace 12 may include other thermal management devices (e.g., thermal insulation components) that reduce heat loss from the melting vessel. Glass melting furnace 12 may include electronic and / or electromechanical devices that facilitate melting of the raw material into molten glass. Glass melting furnace 12 may include support structures (e.g., support chassis, support member, etc.) or other components known to facilitate the manufacture of molten glass.

[0055] Melting vessel 14 may be formed from a refractory material, such as a refractory ceramic material, for example a refractory ceramic material comprising alumina or zirconia,although the refractory ceramic material can comprise other refractory materials, such as yttrium (e.g., yttria, yttria-stabilized zirconia, yttrium phosphate), zirconia (ZrSiCh). alumina- zirconia-silica, or chrome oxide, in any combination. In some examples, melting vessel 14 may be constructed from refractory ceramic bricks.

[0056] In some embodiments, glass melting furnace 12 may be incorporated as a component of a glass manufacturing apparatus configured to fabricate a glass article, for example a glass ribbon, although the glass manufacturing apparatus may be configured to form other glass articles without limitation, such as glass rods, glass tubes, glass envelopes (for example, glass envelopes for lighting devices, e.g., light bulbs) and glass lenses, although many other glass articles are contemplated. In some examples, melting furnace 12 may be included in a glass manufacturing apparatus comprising a slot draw apparatus, a float bath apparatus, a down-draw apparatus (e.g., a fusion down draw apparatus), an up-draw apparatus, a pressing apparatus, a rolling apparatus, a tube drawing apparatus or any other glass manufacturing apparatus that would benefit from the present disclosure. By way of example, FIG. 1 schematically illustrates glass melting furnace 12 as a component of a fusion down-draw style glass manufacturing apparatus 10 for fusion drawing a glass ribbon for subsequent processing into individual glass sheets or rolling the glass ribbon onto a spool. As used herein, fusion drawing comprises flowing molten glass over side surfaces of a forming body, wherein the resulting streams of molten material join, or “fuse,” at the bottom of the forming body to form a glass ribbon.

[0057] Glass manufacturing apparatus 10 may optionally include an upstream glass manufacturing apparatus 16 positioned upstream of melting vessel 14. In some examples, a portion of, or the entire upstream glass manufacturing apparatus 16, can be incorporated as part of the glass melting furnace 12.

[0058] As shown in the embodiment illustrated in FIG. 1, upstream glass manufacturing apparatus 16 can include a raw material storage bin 18, a raw material delivery device 20, and a motor 22 connected to raw material delivery device 20. Raw material storage bin 18 may be configured to store a quantity of raw material 24 that can be fed into melting vessel 14 of glass melting furnace 12 through one or more feed ports in the melting vessel, as indicated by arrow 26. Raw material 24 typically comprises one or more glass forming metal oxides and one or more modifying agents. In some examples, raw material delivery device 20 can be powered by motor 22 to deliver a predetermined amount of raw material 24 from raw material storage bin 18 to melting vessel 14. In further examples, motor 22 can power raw material delivery device 20 to introduce raw material 24 at a controlled rate based on a level of molten glass sensed downstream from melting vessel 14 relative to a flow direction of the molten glass.Raw material 24 within melting vessel 14 can thereafter be heated to form molten glass 28. Typically, in an initial melting step, raw material is added to the melting vessel as particulate, for example as various “sands.” Raw material 24 can also include scrap glass (i.e., cullet) from previous melting and / or forming operations. Combustion burners may be used to begin the melting process. In an electrically boosted melting process, once the electrical resistance of the raw material is sufficiently reduced by combustion heating, electric boost can begin by developing an electrical potential between electrodes positioned in contact with the raw material, thereby establishing an electrical current through the raw material, the raw material typically entering, or in, a molten state. As used herein, the resultant molten material will be referred to as molten glass. Molten glass produced in the melting vessel exits the melting vessel through first exit conduit 29.

[0059] Glass manufacturing apparatus 10 may optionally include a downstream glass manufacturing apparatus 30 positioned downstream of glass melting furnace 12 relative to a flow direction of molten glass 28. Downstream glass manufacturing apparatus 30 may include a first conditioning (e.g., processing) chamber, such as fining vessel 34, located downstream from melting vessel 14 relative to a flow direction of molten glass exiting the melting vessel, and coupled to melting vessel 14 by way of first connecting conduit 32, wherein first connecting conduit 32 is coupled to first exit conduit 29. In some examples, molten glass 28 may be gravity fed from melting vessel 14 to fining vessel 34 by way of first exit conduit 29 and first connecting conduit 32. For instance, gravity may drive molten glass 28 from melting vessel 14 through an interior pathway of first exit conduit 29 and first connecting conduit 32 to fining vessel 34. Accordingly, first connecting conduit 32 and first exit conduit 29 provide a flow path for molten glass 28 from melting vessel 14 to fining vessel 34. It should be understood, however, that other molten glass conditioning vessels may be positioned downstream of melting vessel 14, for example between melting vessel 14 and fining vessel 34. For example, molten glass from a primary melting vessel can be further heated in a secondary melting (conditioning) vessel but to a temperature lower than the temperature of the molten glass in the primary melting vessel before entering the fining chamber.

[0060] Bubbles produced during the melting process may be removed from molten glass 28 by various techniques. For example, raw material 24 may include multivalent compounds (i.e., fining agents) such as tin oxide that, when heated, undergo a chemical reduction reaction and release oxygen. Other suitable fining agents may include, without limitation, arsenic, antimony, iron, and cerium, although the use of arsenic and antimony may be discouraged for environmental reasons in some applications. Fining vessel 34 may be heated, for example toa temperature greater than the melting vessel temperature, thereby heating the fining agent. Oxygen bubbles produced by the temperature-induced chemical reduction of one or more fining agents included in the molten glass rise through the molten glass within the fining vessel. Gases introduced into the molten glass during the melting process can coalesce or diffuse into the oxygen bubbles, whereupon the enlarged gas bubbles with increased buoyancy rise to a free surface of the molten glass within the fining vessel and are vented from the fining vessel.

[0061] The downstream glass manufacturing apparatus 30 may further include another conditioning vessel, such as mixing apparatus 36, for example a stirring vessel, for mixing the molten glass that flows downstream from fining vessel 34. Mixing apparatus 36 can be used to reduce chemical or thermal inhomogeneities in the molten glass, thereby providing a homogenous composition. As shown, fining vessel 34 may be coupled to mixing apparatus 36 by way of a second connecting conduit 38. In some embodiments, molten glass 28 can be gravity fed from fining vessel 34 to mixing apparatus 36 by way of second connecting conduit 38. For instance, gravity may drive molten glass 28 through an interior pathway of second connecting conduit 38 from fining vessel 34 to mixing apparatus 36. Typically, the molten glass within mixing apparatus 36 includes a free surface, with a free volume extending between the free surface and a top of the mixing apparatus. While mixing apparatus 36 is shown downstream of fining vessel 34 relative to the flow direction of the molten glass, mixing apparatus 36 may be positioned upstream from fining vessel 34 in other embodiments. In some embodiments, downstream glass manufacturing apparatus 30 may include multiple mixing apparatus, for example a mixing apparatus upstream from fining vessel 34 and a mixing apparatus downstream from fining vessel 34. These mixing apparatus may be of the same design, or they may be of a different design from one another. In some embodiments, one or more of the vessels and / or conduits can include static mixing vanes positioned therein to promote mixing and subsequent homogenization of the molten glass.

[0062] Downstream glass manufacturing apparatus 30 may further include another conditioning chamber such as delivery vessel 40 located downstream from mixing apparatus 36. Delivery vessel 40 may be used to condition molten glass 28 prior to feeding the molten glass into a downstream forming device. For instance, delivery vessel 40 can act as an accumulator and / or flow controller to provide a consistent flow of molten glass 28 to forming body 42 by way of second exit conduit 44. The molten glass within delivery vessel 40 can, in some embodiments, include a free surface, wherein a free volume extends upward from the free surface to a top of the delivery chamber. As shown, mixing apparatus 36 may be coupled to delivery vessel 40 by way of third connecting conduit 46. In some examples, molten glass28 can be gravity fed from mixing apparatus 36 to delivery vessel 40 by way of third connecting conduit 46. For instance, gravity can drive molten glass 28 through an interior pathway of third connecting conduit 46 from mixing apparatus 36 to delivery vessel 40.

[0063] Downstream glass manufacturing apparatus 30 may further include forming apparatus 48 comprising the above-referenced forming body 42, including inlet conduit 50. Second exit conduit 44 can be arranged to deliver molten glass 28 from delivery vessel 40 to inlet conduit 50 of forming apparatus 48. Forming body 42 in a fusion down-draw glass making apparatus may comprise a trough 52 positioned in an upper surface of the forming body, and converging forming surfaces 54 (only one surface shown) that converge in a draw direction along a bottom edge (root) 56 of the forming body. Molten glass delivered to forming body trough 52 via delivery vessel 40, second exit conduit 44 and inlet conduit 50 overflows walls of trough 52 and descends along the converging forming surfaces 54 as separate flows of molten glass. The separate flows of molten glass join below and along root 56 to produce a single ribbon 58 of molten glass that is drawn along a draw plane in a draw direction 60 from root 56 by applying a downward tension to the glass ribbon, such as by gravity and / or pulling roll assemblies 62, to control the dimensions of the glass ribbon as the molten glass cools and a viscosity of the material increases. Accordingly, glass ribbon 58 goes through a viscoelastic transition to an elastic state and acquires mechanical properties that give glass ribbon 58 stable dimensional characteristics. Glass ribbon 58 may in some embodiments be separated into individual glass sheets 64 by a glass separation apparatus 66, while in further embodiments, glass ribbon 58 may be wound onto spools and stored for further processing.

[0064] Components of downstream glass manufacturing apparatus 30, including any one or more of first exit conduit 29, connecting conduits 32, 38, 46, fining vessel 34, mixing apparatus 36, delivery vessel 40, second exit conduit 44, or inlet conduit 50 may be formed from a precious metal. Suitable precious metals include platinum group metals selected from the group consisting of platinum, iridium, rhodium, osmium, ruthenium and palladium, or alloys thereof. For example, downstream components of the glass manufacturing apparatus may be formed from a platinum-rhodium alloy including from about 70% to about 90% by weight platinum and about 10% to about 30% by weight rhodium. However, other suitable metals for forming downstream components of the glass manufacturing apparatus can include molybdenum, rhenium, tantalum, titanium, tungsten, and alloys thereof.

[0065] Although elements of the glass manufacturing apparatus 10 are shown and described as fusion downdraw glass making elements, principles of the present disclosure can be applied to a wide variety of glass making processes. For example, melting vessels according toembodiments of the present disclosure can be used in such diverse glass making processes as fusion processes, slot draw processes, rolling processes, pressing processes, float processes, tube drawing processes, and so forth.

[0066] To provide an appropriate viscosity of molten glass 58 as the molten glass flows through downstream glass manufacturing apparatus 30 to forming apparatus 48, various components of the downstream glass making apparatus can be temperature controlled, such as by heating and / or cooling of the molten glass. For example, refractory insulating material can be placed about various metallic vessels comprising the downstream glass making apparatus to control heat loss from the metallic vessels. In some embodiments, the metallic vessels can be heated, for example with heating elements proximate the metallic vessels. In some embodiments, an electric current can be established through one or more of the metallic vessels, thereby heating the metallic vessels by direct resistance heating (hereafter, “direct” or “directly” heating). Such directly heated vessels can include one or more of first exit conduit 29, first connecting conduit 32, fining vessel 34, mixing apparatus 36, second connecting conduit 38 extending between fining vessel 34 and mixing apparatus 36, delivery vessel 40, third connecting conduit 46 extending between mixing apparatus 36 and delivery vessel 40, and exit conduit 44. Directly heated vessels may further include forming vessel inlet conduit 50.

[0067] To facilitate delivery of an electric current to directly heated vessels, the directly heated vessels can be provided with electrical current delivery devices configured to provide an electrical current path between cables or bus bars electrically connected to an electrical power source (not shown), and the one or more directly heated vessels. In various embodiments, such electrical current delivery devices may be configured to reduce circumferential non-uniformity in the electrical current delivered to the metallic vessels. Accordingly, in various embodiments, such electrical current delivery devices can extend about an outer periphery of the metallic vessel and are referred to hereinafter as electrical flanges 80 and can be deployed at various locations throughout the downstream glass manufacturing apparatus 30. For example, pairs of electrical flanges 80 can be electrically connected to different electrical phases of multiphase power sources so that temperatures of individual regions of the metallic vessels can be independently controlled to produce one or more heating zones of the same or different temperatures. Thus, the numbers and locations of electrical flanges, and the manner in which they are supplied with an electrical current, is dependent at least on the number of desired heating zones and the physical configuration of the vessel to which the electrical flanges areattached, and the number and location of electrical flanges depicted in FIG. 1 are for purposes of description and not limitation.

[0068] FIG. 2 is a front view of an example electrical flange 80 comprising a body portion 82 and an electrode portion 84 extending outward, away from body portion 82. As shown, body portion 82 can be circular, but other shapes are also contemplated, for example elliptical, egg- shaped, and so forth. Body portion 82 can be configured to extend about an outer periphery of a metallic vessel, e.g., the example conduit 86 shown in FIG. 2, wherein example conduit 86 is representative of any other vessel comprising downstream glass manufacturing apparatus 30 disclosed herein. While example conduit 86 is shown as a cylindrical conduit with a circular cross-sectional shape in a plane orthogonal to a longitudinal axis of the conduit, conduit 86 may have other cross-sectional shapes, such as rectangular, elliptical, oval, or a combination of circular, rectangular, oval, and / or elliptical shapes.

[0069] Electrode portion 84 of electrical flange 80 provides a connection point 88 for electrical conductors 90 (e.g., cables, bus bars, etc.) extending between an electrical power source (not shown) and electrical flange 80. While electrode portion 84 is shown extending vertically upward from body portion 82 in FIG. 2, electrode portion 84 can extend in other orientations, for example vertically downward, horizontally outward or at any other angle between vertical and horizontal. In addition, and as described farther below, electrical flange 80 may comprise more than one electrode portion 84, for example two electrode portions 84 arranged oppositely.

[0070] In embodiments, body portion 82 may comprise a first, outermost ring 92 extending around conduit 86 and formed from a first metal. First ring 92 may be substantially discshaped, for example comprising a disc-shaped annulus. In some embodiments, first ring 92 may comprise a plurality of rings, for example a plurality of concentric rings. The plurality of rings may exhibit, for example, different thicknesses or radial widths.

[0071] In embodiments, body portion 82 may further comprise a second, innermost ring 94 arranged inside first ring 92 (radially inward from first ring 92), in electrical contact therewith, and attached to conduit 86, such as by welding. Second ring 94 may be concentric with first ring 92. Second ring 94 can be formed from a second metal the same or similar to the metal of the vessel to which it is attached. For example, conduit 86 can comprise platinum, for example a platinum-rhodium alloy, in which instance second ring 94 may also comprise platinum, e.g., a similar or the same platinum-rhodium alloy as the vessel to which it is attached, such that second ring 94 can resist the high temperature of conduit 86 when heated by an electrical current. The platinum-rhodium alloy may be any of the platinum-rhodium alloys previously described. Since first ring 92 is spaced radially apart from conduit 86 and separated therefromby at least second ring 94, first ring 92 can be formed from a less expensive metal less able to withstand the high temperature at conduit 86. For example, first ring 92, and electrode portion 84, may comprise nickel, for example a nickel alloy. Body portion 82 may further comprise additional, intermediate rings positioned between first ring 92 and second ring 94. Such intermediate rings can comprise nickel or platinum, as the need and location dictates. For example, intermediate rings positioned between first ring 92 and second ring 94 can comprise platinum, such as any of the platinum-rhodium alloys described herein. Such intermediate rings can have a thickness equal to the thickness of second ring 94, or such intermediate rings can have a thickness that differs from second ring 94. In some embodiments, the thickness of the rings can increase or decrease as a function of radial distance from conduit 86 such that as the radial distance increases, the thickness of a given ring is increased. Moreover, because first ring 92 is spaced apart from conduit 86 and can be formed from a less expensive metal than second ring 94, first ring 92 may be made thicker than second ring 94 and / or platinum- containing intermediate rings positioned therebetween. The additional mass of first ring 92 can provide greater current carrying capacity to first ring 92, but simultaneously may add additional weight to electrical flange 80.

[0072] In various embodiments, an electrical flange 80 may be provided with a cooling device 96, such as a cooling tube extending around an outer periphery of body portion 82 and optionally electrode potion 84. A cooling fluid, for example water, can be flowed through a passage in the cooling tube to extract heat from the electrical flange and prevent thermal damage thereto.

[0073] FIG. 3 is a front view of another embodiment of electrical flange 80 comprising a plurality of electrode portions 84, in this instance two electrode portions extending oppositely and outward from body portion 82. Additionally, in the embodiment of FIG. 3 , a center defined by second ring 94, may not coincide with a center of conduit 86 such that the center of conduit 86 (designated by an “x”) is offset from the center of second ring 94 (designated by a circle “o”) by a distance 5. That is, in some embodiments, second ring 94 may not be concentric with first ring 92. An electrical flange such as shown in FIG. 3 may be used, for example, where insufficient space exists for the electrical flange to extend well below the conduit. However, such offset flange portions as described herein are not limited to embodiments comprising multiple electrode portions, but may be used in other electrical flanges, such as the electrical flange of FIG. 2.

[0074] FIG. 4 illustrates a portion of glass manufacturing apparatus 10 comprising an example melting vessel 14, first exit conduit 29, first connecting conduit 32, and at least a portion of fining vessel 34 comprising a free volume 95 located above a surface of molten glass 28. Free volume 95 collects gases released from the molten glass and is in fluid communication with an ambient atmosphere through a vent (not shown). First exit conduit 29 extends through a refractory wall, e.g., front wall 98, of melting vessel 14, in a direction toward fining vessel 34. First exit conduit 29 comprises a passage for conveying molten glass 28 from an interior of melting vessel 14 to fining vessel 34. First connecting conduit 32 can extend from first end 100 of fining vessel 34 in a direction toward melting vessel 14. In the embodiment of FIG. 4, first connecting conduit 32 and fining vessel 34 can be rigidly joined, for example welded together at first end 100 so that first connecting conduit 32 and fining vessel 34 are physically and electrically connected.

[0075] During heat-up of glass manufacturing apparatus 10, for example during an initial startup of the glass manufacturing apparatus, vessels for conveying molten glass are heated prior to the introduction of molten material therethrough. During heat-up the metallic vessels of the glass manufacturing apparatus may expand, for example in an expansion direction coinciding with longitudinal axes of the individual vessels. For example, fining vessel 34 can be an elongate tube extending along a longitudinal axis 101. Accordingly, fining vessel 34 may expand along an expansion direction corresponding to, such as generally parallel to, the longitudinal axis of the fining vessel. Similarly, various other vessels (e.g., conduits), may also expand along their respective longitudinal axes. If all the various metallic vessels of the glass manufacturing apparatus are rigidly connected, for example by welding or bolting, considerably stress could be applied to these metallic vessels. Indeed, even if various vessels are unfixed in position, there may be sufficient mass present (e.g., from refractory insulating materials, structural members supporting the vessel, etc.) that considerable force is needed to move the vessel. For example, if fining vessel 34 is fixed in position, and melting vessel 14 is fixed in position, if first connecting conduit 32 rigidly attached to fining vessel 34 is similarly rigidly connected to first exit conduit 29 (generally rigidly attached to melting vessel 14), the forces resulting from expansion of fining vessel 34 and first connecting conduit 32 in a direction toward melting vessel 14 might warp and / or crush first connecting conduit 32 or first exit conduit 29. Additionally, electrical flanges attached to ends of the various vessels (e.g., conduits) may be unable to provide sufficient sealing between opposing ends of the vessels, thereby leading to molten glass leaking from the joint. Because many of the metallic vessels of glass manufacturing apparatus 10 are formed from a precious metal, e.g., platinum or alloysthereof, and thus can represent considerable cost, the walls of the vessels are made thin to reduce cost but are therefore unable to tolerate significant stress without damage, such as shearing, buckling, or other deformation. To avoid stress related to thermal expansion of the metallic vessels, certain metallic vessels, or groups of metallic vessels, may not be rigidly joined. Instead, adjacent vessels, or assemblies of vessels, may instead be movably mounted, such as on rollers. Individual vessels may be aligned and positioned proximate each other but separated by a gap to accommodate thermal expansion.

[0076] Once heat-up of the glass manufacturing apparatus is completed and thermal expansion has substantially ceased, adjacent vessels, or assembly of vessels, can be further moved, such as rolled on tracks, to close substantially all the remaining gap. For example, the melting vessel, including first exit conduit 29 may be moved toward fining vessel 34, and fining vessel 34, including first connecting conduit 32, may be moved toward melting vessel 14. In some instances, a small portion of the gap, for example a gap equal to or less than about one quarter of a centimeter, may remain between a distal end of first exit conduit 29 and first connecting conduit 32. This gap may not be consistent around a circumference of the adjacent conduits. After batch materials are melted in the melting vessel to form molten glass and the molten glass begins flowing through the metallic vessels, the molten glass may seep through any remaining gap between adjacent metallic vessels. Cooling of molten glass in the gap between adjacent vessels or assemblies of vessels, for example by exposure to the surrounding environment, causes the gap to be filled and plugged, limiting continued flow of the molten glass from the gap and forming a glass seal between components. Owing to their broad surfaces in comparison to the thin edges of ends of conduits, sealing may be facilitated by electrical flanges on opposing distal ends of the adjacent conduits, as will be described more fully below.

[0077] In the embodiment of FIG. 4, first connecting conduit 32 and fining vessel 34 form metallic vessel assembly 102 comprising a contiguous passage therethrough. While not shown, metallic vessel assembly 102 may be contained within an enclosure, for example a metallic enclosure. In some embodiments, the enclosure may be configured for controlling an atmosphere between walls of metallic vessel assembly 102 and walls of the enclosure. For example, in some embodiments, the enclosure may be in fluid communication with a source of hydrogen (e.g., water vapor) to control a partial pressure of hydrogen within the atmosphere. By maintaining a partial pressure of hydrogen within the metallic enclosure at a predetermined concentration or within a predetermined concentration range, hydrogen permeation can be controlled. Hydrogen permeation refers to the breakdown of water contained within the molten glass, and a subsequent passage of hydrogen from the molten glass flowing within the metallicvessel assembly through the walls of the metallic vessel assembly to the atmosphere outside the metallic vessel assembly walls. Oxygen left behind in the molten glass can form small bubbles (e.g., blisters), in the molten glass, which may be detrimental to a subsequently-formed glass product. Refractory insulating material may be disposed between metallic vessel assembly 102 and the enclosure to control heat loss from the walls of the metallic vessel assembly and to provide support to the thin-walled metallic vessel assembly.

[0078] As described above, metallic vessel assembly 102 may further comprise a plurality of electrical flanges 80 arranged and configured to heat metallic vessel assembly 102 by conducting an electrical current through the metallic vessel assembly. The number of electrical flanges 80 attached to metallic vessel assembly 102, and their placement, depends on need, for example depending on the number and location of temperature zones desired.

[0079] In embodiments, first exit conduit 29 may be fitted with an electrical flange 80 at a distal end of the exit conduit, i.e., the end of first exit conduit projecting from front wall 98 of melting vessel 14. In the embodiment of FIG. 4, the electrical flange 80 attached to the distal end of first exit conduit 29 is of a type depicted in FIG. 3, although other designs of electrical flanges may be used, such as the electrical flange of FIG. 2. Similarly, an electrical flange 80, for example of the type illustrated in FIG. 2, may be attached to a distal end of first connecting conduit 32, i.e., the end of first connecting conduit extending from fining vessel 34 and nearest first exit conduit 29.

[0080] Prior to heating the glass manufacturing apparatus, metallic vessel assembly 102 can be moved into position such that first connecting conduit 32 is aligned with first exit conduit 29. Metallic vessel assembly 102 may then be positioned such that gap G is formed between distal ends of first connecting conduit 32 and first exit conduit 29. As metallic vessel assembly 102 and first exit tube 29 are heated via by their respective electrical flanges 80, metallic vessel assembly 102 expands in a length-wise direction, toward melting vessel 14, thereby reducing gap G. Similarly, first exit tube 29 expands in a length-wise direction, toward fining vessel 34. Subsequent molten glass flow from melting vessel 14 through first exit conduit 29 and metallic vessel assembly 102 seeps into gap G, forming glass seal 74 within gap G that seals first connecting conduit 32 to first exit conduit 29. Described more generally, metallic vessel assembly 102 is not rigidly connected to first exit tube 29. Thus, individual components are heated first, then pushed together when an operating temperature is reached and molten glass forms a seal therebetween. More specifically, since both first exit conduit 29 and first connecting conduit 32 include electrical flanges 80 positioned at their respective distal ends, a seal may be formed between at least the respective second rings of the opposing electricalflanges by molten glass that seeps through gaps between the opposing electrical flanges. The molten glass that seeps between the flanges cools and a viscosity thereof increases, forming the seal.

[0081] Stress produced in electrical flanges, particularly multicomponent electrical flanges comprising a thick outermost ring and a thinner innermost ring, can produce stress in the electrical flange capable of buckling at least the thinner innermost ring. Buckling of flanges on the first exit conduit and / or first connecting conduit flange can occur when external force is transferred to the thin platinum portion of the electrical flange due to a difference in expansion between the platinum and the external nickel portion of the electrical flange, and the buckling load exceeds the permissible value. For example, as previously described, electrical flanges 80 may include a cooling tube 96 along an edge of the electrical flange (e.g., around a perimeter of the first ring) that may create a radial thermal gradient sufficiently large to induce buckling in portions of the electrical flange, such as the second ring. Buckling of the second, innermost ring can be problematic when two such electrical flanges are pushed against each other to mate one subcomponent to another subcomponent, for example first exit conduit 29 and metallic vessel assembly 102. For example, using the arrangement of FIG. 4 as an illustration, if an electrical flange positioned at the distal end of first exit conduit 29 exhibits buckling and / or an electrical flange positioned at the distal end of first connecting conduit 32 exhibits buckling, when the melting vessel, including first exit conduit 29, and metallic vessel assembly 102, including first connecting conduit 32, are pushed together, insufficient contact may be made between the innermost ring of the two electrical flanges and one or more gaps may be formed therebetween.

[0082] Ideally, the innermost rings of the opposing and adjacent electrical flanges should be flat when pushed together, thereby producing good contact between at least the innermost rings of the opposing and adjacent electrical flanges. The high temperature of the innermost rings (e.g., at a temperature between about 1400°C and 1700°C) may be sufficient to cause diffusion bonding between the opposing and adjacent innermost rings. If the innermost rings are sufficiently flat, with good contact therebetween, the distal end electrical flange of first exit conduit 29 and the distal end electrical flange of first connecting conduit 32 can become well- bonded (diffusion bonded) around an entirety of a circumferential annulus of the respective second, innermost rings of the electrical flanges, such as around a circumference thereof, thereby preventing leakage of molten glass. On the other hand, if gaps exist between the second, innermost rings of the adjacent electrical flanges, molten glass flowing through thepassageways of first exit conduit 29 and first connecting conduit 32 fills the gaps. The molten glass in the gaps cools at an exterior surface thereof when exposed to the cooler air outside first exit conduit 29 and first connecting conduit 32, but may be less viscous farther in, radially. Additionally, cooling tubes about a periphery of the outermost ring of one or both electrical flanges cools the outermost ring thereof. Thus, an outermost periphery of the innermost ring may be cooler, via conduction with the outermost ring, than an interior of the innermost ring, where the innermost ring is attached to the respective conduit, resulting in greater viscosity about the atmospherically-exposed portion of the glass seal, but wherein an interior portion of the glass seal may still be fluid. Put another way, glass seeping into the gaps between the second rings of the respective opposing electrical flanges forms a high viscosity outer skin, but an interior portion of the glass seal may remain sufficiently fluid that bubble transport into the glass seal is possible. If a sufficiently sized gap or gaps are created at electrical flange interfaces, such as by having one or both second, innermost rings non-flat (buckled), once molten glass is flowed through the system gas bubbles 104 produced in the melting vessel during the melting process can become entrained in the flow of molten glass through first exit tube 29 and first connecting conduit 32 and accumulate in the gap or gaps between their respective electrical flanges. While not wishing to be held to theory, it is believed an oxidation reaction may occur where such bubbles are in contact with the platinum-containing metal of the inner rings that generates a platinum oxide gas. Platinum oxide gas subsequently condenses on portions of the innermost ring that may be cooler than others, i.e., below a condensation temperature of the platinum oxide gas. The condensed material accumulates and may, in time, break free and make its way into the molten glass stream traveling through first exit conduit 29 and first connecting conduit 32, thereby producing metallic contaminants in the molten glass that may make their way to the final glass product, for example glass ribbon or glass sheet.

[0083] Buckling of second ring 94 may be reduced by forming a stress relief feature in a predefined area of electrical flange 80. For example, a stress release feature may be created by forming a portion of the electrical flange out-of-plane with other portions of the electrical flange. Accordingly, FIG. 5 illustrates a cross-sectional edge view of an electrical flange 200 comprising a body portion 202 and an electrode portion 204, body portion 202 comprising a first, outermost ring 206 and a second, innermost ring 208. Electrical flange 200 may be used wherever electrical flange 80 is used. First ring 206 may comprise nickel, whereas second ring 208 may comprise platinum, for example a platinum-rhodium alloy. In embodiments, second ring 208 may comprise platinum in a range from about 70% by weight (wt.%) to 100 wt.% and rhodium in a range from about 0 wt.% to about 30 wt.%. However, second ring 208 maycomprise another metal, for example another platinum group metal (e.g., ruthenium, rhodium, palladium, osmium, iridium) in a range from about 0 wt.% to about 30 wt.%. A thickness of second ring 208 may be less than a thickness of first ring 206. Electrical flange 200 (e.g., second ring 208) may include a curved annular shape (e.g., ogee) that places at least one portion of second ring 208 out of plane with another portion of second ring 208. That is, second ring 208 may comprise one portion defining one plane and another portion defining another plane out-of-plane with the first plane. Electrode portion 204 is joined to body portion 202, e.g., first ring 206, and extends outward, away from body portion 202. A distal end of electrode portion 204 includes connections 210 for electrical cables configured to supply electrical flange 200 with electrical current from an electrical current source (not shown).

[0084] As described, in embodiments, second ring 208 may comprise an out-of-plane portion. As used herein, the out-of-plane portion refers to a portion of second ring 208 that does not lie within or substantially within a plane of another portion of second ring 208. That is, a portion of second ring 108 may be extended relative to another portion of second ring 208. Referring to FIG. 5, in embodiments, second ring 208 may include a first portion 212 that defines a first plane 214, a second portion 216 defining a second plane 218 spaced apart from first plane 214 by distance 220, and a third, transition portion 222 joining first portion 212 and second portion 216. Third portion 222 may comprise, for example, a double curve shape (e.g., “S” curve, ogee) formed by two arcs facing in opposite directions, e.g., a concave arc and a convex arc. As best seen in FIG. 6, third portion 222 includes a first arc 224 and a second arc 226. Third portion 122 may further comprise a flat (linear) part 228 disposed between first arc 224 and second arc 226. An angle a of flat part 228 relative to first plane 214 of first portion 212 (where plane 227 is an arbitrary plane parallel to first plane 214 and dashed line 229 is represents a line parallel to flat part 228 in the illustrated cross-section of third portion 222) may be in a range from about 115 degrees to about 125 degrees, for example in a range from about 16 degrees to about 124 degrees, in a range from about 117 degrees to about 123 degrees, in a range from about 118 degrees to about 122 degrees, or in a range from about 119 degrees to about 121 degrees, including all ranges and subranges therebetween. Distance 220 may be in a range from about 0.6 centimeters (cm) to about 1.9 cm, for example in a range from about 1 cm to about 1.5 cm, or in a range from about 1.2 cm to about 1.4 cm, including all ranges and subranges therebetween.

[0085] In some embodiments, first portion 212 may be parallel with second portion 216. That is, first plane 214 may be parallel with second plane 218. In embodiments, first plane 214and / or second plane 218 may be parallel with a third plane 230 defined by first ring 206 (see FIG. 5). In other embodiments, first portion 212 may be nonparallel with first ring 206 (i.e., first plane 214 may be nonparallel with third plane 230). For example, first portion 212 of second ring 208 may be arranged relative to first ring 206 such that first plane 214 defined by first portion 212 of second ring 208 is tilted at an angle P in a range from about 0.25 degrees to about 0.75 degrees, such as in a range from about 0.35 degrees to about 0.65 degrees, or in a range from about 0.4 to about 0.5 degrees relative to third plane 230, including all ranges and subranges therebetween. In other words, at least a portion of first portion 212 may be recessed below first major surface 232 of first ring 206 a distance 5 a range from about 0.25 inches to about 0.75 inches. In embodiments, a bottom portion of first portion 221 may be recessed relative to a surface of first ring 206. By arranging first portion 212 of second ring 208 at an angle relative to first ring 206, when two adjacent conduits are aligned such that the first rings of their respective distal end electrical flanges are substantially parallel, when the flanges are placed in contact with each other, the angle ensures the second rings 208, and more specifically, the second portions 216 of the opposing and adjacent electrical flanges contact first, and more particularly the top portions of the second portions 216 of the second rings 216 contact first. This ensures good sealing at the top portions of the adjacent second portions 216 and that no gaps are formed between the top portions of the second portions 216 of the electrical flanges, thereby mitigating against the formation of air pockets between the adjacent second portions 216. In embodiments, a width D of second portion 216 is at least about 5 centimeters.

[0086] In embodiments, a maximum buckling (deformation) of electrical flanges including out-of-plane second ring portions disclosed herein may be kept equal to or less than 13 mm, such as equal to or less than about 12.5 mm, at operating temperatures (i.e., in a range from about 1400°C to about 1700°C). For example, in embodiments, a method of joining subsystems of a glass manufacturing apparatus may comprise preheating a first subsystem of the glass manufacturing system to a first temperature in a range from about 1400°C to about 1700°C, the first subsystem comprising a first conduit comprising a first electrical flange disposed on a distal end of the first conduit, the first electrical flange comprising a first ring comprising a first metal, and a second ring attached to the first ring and the first conduit and comprising a second metal different from the first metal. The second ring may comprise a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion, and wherein the second plane is spaced apart from the first plane. The third portion of the second ring of the first electrical flange maycomprises a strain relief feature. The strain relief feature may comprises a curved portion, such as an “S” curve or ogee that spaces the second plane from the first plane.

[0087] The method may further comprise preheating a second subsystem of the glass manufacturing apparatus to a second temperature in a range from about 1400°C to about 1700°C, the second subsystem comprising a second conduit, the second conduit comprising a second electrical flange attached to a distal end of the second conduit, the second electrical flange comprising a first ring comprising the first metal, a second ring attached to the first ring and the second conduit and comprising the second metal. The second ring may comprise a first portion defining a first plane, a second portion defining a second plane spaced apart from the first plane of the second electrical flange, and a third portion joining the first and second portions of the second ring of the second electrical flange. The third portion of the second ring of the first electrical flange may comprises a strain relief feature. The strain relief feature may comprise a curved portion, such as an “S” curve or ogee that spaces the third plane from the second plane.

[0088] The method may still further comprise moving at least one of the preheated first subsystem or the preheated second subsystem such that the second ring of the first electrical flange contacts the second ring of the second electrical flange and a maximum deformation of the second portion of the second ring of the first electrical flange or the second portion of the second ring of the second electrical flange, after the preheating the first subsystem and the second subsystem, does not exceed 13 mm. The deformation of the second portion of the second ring of with the first electrical flange or the second electrical flange may be measured by placing a straight edge, such as a metal straight edge, across the flange portion to be measured (e.g., the second portion), and measuring with a ruler a distance between the farthest portion of the flange from the edge of the straight edge. However, at the operating temperatures of the flanges, at least a portion of the metal straight edge may melt, causing potential contamination of the molten glass should a portion of the straight edge fall through a gap between the opposing electrical flanges. Alternatively, a laser may be used to direct a laser beam across the subject ring of the subject electrical flange, generally orthogonal to a longitudinal axis of the conduit to which the electrical flange is attached, such that the laser beam just touches two adjacent portions of the portion of the electrical flange being measured, wherein the two adjacent portions represent “high” positions on the portion of the electrical flange. This can be visualized using a sine wave as a simple example. The laser beam is positioned such that the beam is directed parallel to the propagation direction of thesine wave, with the beam just touching two adjacent peaks of the sine wave, then measuring a distance from the intervening valley between the peaks, from the valley to the laser beam and orthogonal to the laser beam. With regard to the two opposing electrical flanges, the distance from the “low” spot on the flange to the laser beam may be measured with a wooden ruler to avoid metal contamination of the molten glass traveling through the conduits. Multiple measurements may be taken at different positions around the electrical flange to determine the maximum deformation.

[0089] In addition to buckling mitigation, the use of out-of-plane electrical flanges allows for visual confirmation of leakage, or the absence thereof, as the sealing portions of the electrical flange, i.e., the second portions of the second ring, are extended relative to the first portions. When two such electrical flanges are positioned in an opposing relationship (see FIG. 7), such as setting an appropriate gap prior to heating, the sealing area of the electrical flanges is visible. In embodiments, when two such electrical flanges are positioned in an opposing relationship after heating, a distance 232 between the first ring 212 of the first electrical flange 200 from the first ring 212 of the second electrical flange is equal to or less than about 3 cm, for example equal to or less than about 2.5 cm.

[0090] Finite element analysis has shown that an out-of-plane flange design exhibits improved buckling resistance compared to a fully in-plane design. Electrical current density analysis has not identified problematic hot spots when accounting for the initial non-flatness of the flange surface.

[0091] In some embodiments, at a least a portion of the electrical flange may be coated with a coating, for example a stabilized zirconia coating. For example, in embodiments, at least one of first portion 212 or third portion 222 of second ring 208 may be coated with a coating 234 (see FIG. 6).

[0092] A change to the geometry of the flanges at the interface is described that may mitigate non-uniformity of the flange face thus improving probability of creating a good seal. The creates a strain relief in the flange geometry, thereby preventing random buckling modes across the flange body that avoids variability in geometry across the flange body. It may also allow for improved observation of the seal interface by moving portions of the flange out of plane. Improved sealing between electrical flanges mitigates against metal (e.g., platinum) defects appearing in glass products.

[0093] While the present disclosure has been presented mainly in regard to the use of electrical flanges positioned at distal ends of first exit conduit 29 and first connecting conduit 32,electrical flanges disclosed herein may provide benefit in any location along the downstream glass manufacturing apparatus 30.

[0094] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiments of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A glass manufacturing apparatus, comprising: a conduit configured to convey molten glass; an electrical flange comprising a body portion and an electrode portion extending away from the body portion, the body portion comprising a first ring comprising a first metal, a second ring comprising a second metal different than the first metal, the second ring comprising a first portion defining a first plane, a second portion attached to the conduit and defining a second plane, and a third portion joining the first portion and the second portion; and wherein the second plane is spaced apart from the first plane.

2. The glass manufacturing apparatus of claim 1, wherein the third portion comprises a first arc and a second arc in a cross-section of the second ring, the second arc facing a direction opposite a direction of the first arc.

3. The glass manufacturing apparatus of claim 2, wherein the third portion comprises a linear portion between the first arc and the second arc in the cross-section of the second ring, and an angle of the linear portion relative to the first plane is in a range from about 115 degrees to about 125 degrees.

4. The glass manufacturing apparatus of claim 1, wherein a width of the second portion is equal to or greater than about 5 cm.

5. The glass manufacturing apparatus of claim 1, wherein the first plane is parallel with the second plane.

6. The glass manufacturing apparatus of claim 5, wherein the first ring defines a third plane, and the first plane is not parallel with the third plane.

7. The glass manufacturing apparatus of claim 1, wherein the first plane is spaced apart from the second plane by a distance in a range from about 0.6 cm to about 1.9 cm.

8. The glass manufacturing apparatus of claim 1, wherein the first ring comprises nickel.

9. The glass manufacturing apparatus of claim 1, wherein the second ring comprises platinum.

10. The glass manufacturing apparatus of claim 1, further comprising a second electrical flange disposed on a second conduit, the second conduit arranged such that the second electrical flange is opposite to and in contact with the first electrical flange.

11. The glass manufacturing apparatus of claim 10, wherein the glass manufacturing apparatus comprises a refractory melting vessel and the second conduit extends from the refractory melting vessel.

12. The glass manufacturing apparatus of claim 10, wherein the second electrical flange comprises a second body portion and a second electrode portion extending away from the second body portion, the second body portion comprising a first ring comprising the first metal, and a second ring comprising the second metal, the second ring of the second body portion comprising a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion of the second ring of the second body portion; and wherein the second plane of the second portion of the second ring of the second body portion is spaced apart from the first plane of the second portion of the second ring of the first body portion.

13. The glass manufacturing apparatus of claim 12, wherein the second portion of the second ring of the second body portion extends outward toward the first electrical flange and the second portion of the second ring of the first body portion extends outward toward the second electrical flange.

14. The glass manufacturing apparatus of claim 12, wherein the first ring of the first electrical flange is spaced apart from the first ring of the second electrical flange by a distance equal to or less than about 2.5 cm.

15. The glass manufacturing apparatus of claim 1, wherein at least the first portion of the second ring is coated with a stabilized zirconia coating.

16. A method of joining subsystems of a glass manufacturing apparatus, comprising: preheating a first subsystem of the glass manufacturing system to a first temperature in a range from about 1400°C to about 1700°C, the first subsystem comprising a first conduit, the first conduit comprising a first electrical flange disposed on a distal end of the first conduit, the first electrical flange comprising a first ring comprising a first metal, and a second ring attached to the first ring and the first conduit and comprising a second metal different from the first metal, the second ring comprising a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion, and the second plane is displaced from the first plane; preheating a second subsystem of the glass manufacturing apparatus to a second temperature in a range from about 1400°C to about 1700°C, the second subsystem comprising a second conduit, the second conduit comprising a second electrical flange attached to a distal end of the second conduit, the second electrical flange comprising a first ring comprising the first metal, a second ring attached to the first ring and the second conduit and comprising the second metal, the second ring comprising a first portion defining a first plane, a second portion defining a second plane, and a third portion joining the first portion and the second portion of the second ring of the second electrical flange, and the second plane is spaced apart from the first plane; moving at least one of the preheated first subsystem or the preheated second subsystem such that the second ring of the first electrical flange contacts the second ring of the second electrical flange; and a maximum deformation of the second portion of the second ring of the first electrical flange or the second portion of the second ring of the second electrical flange, after the preheating the first subsystem and the second subsystem, does not exceed 13 mm.

17. The method of claim 16, wherein the third portion of the second ring of the first electrical flange comprises a strain relief feature.

18. The method of claim 16, wherein the third portion of the second ring of the first electrical flange comprises a first arc and a second arc in a cross-section of the second ring of the first electrical flange, the second arc facing a direction opposite a direction of the first arc.

19. The method of claim 18, wherein the third portion of the second ring of the first electrical flange comprises a linear portion between the first arc and the second arc in the cross-section of the second ring of the first electrical flange, and an angle of the linear portion relative to the first plane of the first portion of the second ring of the first electrical flange is in a range from about 115 degrees to about 125 degrees.

20. The method of claim 16, wherein a width of the second portion of the second ring of the first electrical flange is equal to or greater than 5 cm.

21. The method of claim 16, wherein the first ring of the first electrical flange defines a third plane, and the first plane of the first portion of the first electrical flange is not parallel with the third plane of the first ring of the first electrical flange.

22. The method of claim 16, wherein after the moving, at least a portion of the first electrical flange is bonded to at least a portion of the second electrical flange.

23. The method of claim 22, wherein the at least a portion of the first electrical flange is diffusion bonded to the at least a portion of the second electrical flange.

24. The method of claim 22, wherein the second portion of the second ring of the first electrical flange is bonded to the second portion of the second ring of the second electrical flange.

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