Method for forming a glass article

Abstract

A method of making a glass article is disclosed herein, comprising passing molten glass through a first vessel to a second vessel downstream, the stream of molten glass passing through a conduit connecting the first vessel to the second vessel, and the first vessel and the conduit defining a continuous free volume above a free surface of the molten glass, the continuous free volume extending into at least a portion of the conduit. The method further comprises venting a first atmosphere contained in the free volume to a second atmosphere outside the first vessel through a vent tube connected to the conduit near a top of the conduit and above the free surface, the vent tube extending from the conduit along a longitudinal axis downward to a distal end of the vent tube at an angle a with respect to horizontal and providing fluid communication between the first and second atmospheres.

Description

TECHNICAL FIELD

[0001] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63 / 064,642, filed August 12, 2020, the contents of which are incorporated herein by reference in their entirety.

[0002] The present application relates to a method for forming a glass article; more specifically, the present application relates to a method of venting a vessel containing or transporting molten glass during article manufacturing. BACKGROUND

[0003] Clarifying molten glass during glass manufacturing processes helps to remove dissolved gases from the molten glass, which helps to produce bubble-free glass products. Increasing the temperature of the molten glass to a temperature above the melting temperature causes one or more clarifiers in the molten glass to release oxygen gas. The oxygen gas combines with the melting-related gases, and the resulting gas mixture bubbles rise to the surface of the molten glass. The bubbles burst and the released gases fill the free volume of the clarifying vessel. These gases must be removed from the clarifying vessel. However, whether directly from the clarifying vessel through its top, either spontaneously or when the exhaust pipe is cleaned to remove condensate, there is a risk of condensate particles falling from the exhaust pipe into the underlying molten glass. SUMMARY

[0004] According to the present application, a method of manufacturing a glass article is disclosed, comprising: flowing a molten material through a first vessel to a second vessel downstream of the first vessel, the molten material flowing through a conduit connecting the first vessel and the second vessel, the first vessel and the conduit defining a continuous free volume above a free surface of the molten material, the free volume extending into at least a portion of the conduit. The method further comprises: venting a first atmosphere contained in the free volume to a second atmosphere outside the first vessel through an exhaust pipe, the exhaust pipe comprising a proximal end, a distal end opposite the proximal end, and a passage extending between the proximal end and the distal end, the proximal end being connected to the conduit proximate a top of the conduit and above the free surface, the exhaust pipe extending downward and away from the conduit at an angle a relative to a horizontal plane, and providing fluid communication between the first atmosphere and the second atmosphere.

[0005] The exhaust pipe can be straight between the proximal end and the distal end, without bends or kinks. The proximal end is attached to the first vessel.

[0006] In various embodiments, the angle a is in a range from greater than 0° to less than 90°, for example, in a range from about 3° to about 80°, in a range from about 3° to about 40°, in a range from about 3° to about 20°, or in a range from about 3° to about 10°.

[0007] In some embodiments, the method can further include heating the exhaust tube during the exhausting. The heating can include establishing an electrical current in a heating element. The heating element can include a wall of the exhaust tube, or the heating element can be one or more separate discrete heating elements disposed proximate to the wall of the exhaust tube.

[0008] When the exhaust tube wall is a heating element, the heating step can include establishing an electrical current between a first electrical flange connected to the exhaust tube and a second electrical flange connected to at least one of the first vessel or the conduit.

[0009] In various embodiments, the first vessel can be a fining vessel.

[0010] In various embodiments, the second vessel can be a mixing vessel.

[0011] The method can further include flowing the molten material into a forming body and shaping the molten material into a glass ribbon. In some embodiments, the shaping can include drawing the molten material downward from the forming body.

[0012] In some embodiments, a first portion of the conduit can extend horizontally from the first vessel, and the exhaust tube can be connected to the first portion. In some embodiments, a second portion of the conduit extends downward relative to horizontal. The second portion can be downstream of the first portion relative to a direction of flow of the molten glass through the conduit. The second portion can be attached to the first portion. In some embodiments, the conduit can include a first segment and a second segment, where the first conduit portion and the second conduit portion include the first conduit segment. The conduit can further include a second segment coupled to the first conduit segment (e.g., the second conduit portion) by a glass seal.

[0013] The method can further include flowing a cover gas into the free volume through a gas delivery tube connected to the first vessel. The gas can include an inert gas. The gas can include oxygen. The gas can be a mixture of an inert gas and oxygen. The gas can be a humidified gas.

[0014] The method can further include heating the conduit while the molten material flows through the conduit. In some embodiments, a thickness of the conduit wall varies along a length of the conduit. That is, in a cross-section of the conduit orthogonal to a longitudinal axis of the conduit, the thickness of the conduit wall in a first portion of the cross-section is different than the thickness of the conduit wall in a second portion of the cross-section. In some embodiments, a circumferential thickness of the conduit wall can vary along a length of the conduit. In some embodiments, the thickness can vary as a function of both the circumference and the length. In other embodiments, a method of making a glass article is described, including flowing a molten material from a first vessel through a conduit connected to the first vessel, the first vessel and the conduit defining a continuous free volume above a free surface of the molten material, the free volume extending into a portion of the conduit.

[0015] The method can further include venting the first atmosphere contained in the free volume to a second atmosphere outside the first vessel through a vent tube, the vent tube including a proximal end and a distal end opposite the proximal end, the proximal end being connected to the conduit near the top of the conduit and above the free surface, the vent tube extending downward along the longitudinal axis at an angle a relative to the horizontal plane, and providing fluid communication between the first atmosphere and the second atmosphere.

[0016] The method can further include heating the vent tube while the molten material is flowing, the heating removing condensate accumulated on an inner surface of the vent tube. The heating can include establishing an electrical current in a heating element, for example in a wall of the vent tube, where the vent tube is the heating element. For example, the heating can include establishing an electrical current between a first electrical flange connected to the vent tube and a second electrical flange connected to at least one of the first vessel or the conduit.

[0017] The method can further include flowing the molten material into a forming body that shapes the molten material into a glass article. In some embodiments, the glass article can be a glass ribbon. The forming step can include drawing the molten material downward from the forming body.

[0018] In some embodiments, the first vessel can be a fining vessel.

[0019] In some embodiments, the second vessel can be a mixing apparatus.

[0020] In some embodiments, at least a first portion of the conduit extends downward relative to the horizontal plane. For example, in some embodiments, the first portion of the conduit extends horizontally from the first vessel and the vent tube is connected to the first portion of the conduit. In some embodiments, a second portion of the conduit extends downward from the first portion of the conduit.

[0021] In some embodiments, the conduit can include a first segment and a second segment, where the first segment is coupled to the second segment by a glass seal.

[0022] In some embodiments, the method can further include flowing a gas into the free volume through a gas delivery tube. The gas delivery tube can be connected to the first vessel. In some embodiments, the cover gas can include an inert gas, for example nitrogen. The cover gas can be a low-oxygen gas including less than about 1.5% oxygen (O2) by volume, for example in a range of about 0.075% to about 1.5% by volume. In some embodiments, the cover gas can be a humidified gas. In some embodiments, the cover gas can be a dry gas.

[0023] Additional features and advantages of the embodiments disclosed herein will be set forth in the following [Description of Embodiments], and those skilled in the art will partly understand these additional features and advantages from the [Description of Embodiments], or by practicing the embodiments described herein, including the following [Description of Embodiments], the claims, and the drawings.

[0024] It should be understood that the embodiments presented in both the [Summary of the Invention] above and the [Embodiments] below are intended to provide an overview or framework for understanding the nature and features of the embodiments disclosed herein. This application includes accompanying drawings to provide further understanding, and the drawings are incorporated in and form a part of this specification. The drawings illustrate various embodiments of the present application and, together with this specification, explain the principles and operation of the present application. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an exemplary glass manufacturing apparatus;

[0026] Figure 2 This is a schematic diagram of an exemplary connecting conduit extending between a clarification container and a mixing device;

[0027] Figure 3 This is a side cross-sectional view of an exemplary clarification container, showing a gas delivery pipe configured to provide covering gas to the free volume of the clarification container;

[0028] Figure 4 This is a detailed cross-sectional view of a portion of an exemplary gas delivery pipe;

[0029] Figure 5 yes Figure 2 Part of an exemplary connecting conduit, Figure 5 It shows from Figure 2 An exemplary connection conduit extending into an exhaust pipe;

[0030] Figure 6 It is along Figure 5 Line 6-6 (review) Figure 5 A view of the connecting conduit;

[0031] Figure 7 This is a cross-sectional side view of another embodiment of the connecting conduit, which has a dome-shaped portion near the clarifying container to which the connecting conduit is attached;

[0032] Figure 8 It is along Figure 7 Line 8-8 (review) Figure 7 A view of the connecting conduit. Figure 8 An exhaust pipe extending from the dome portion is shown;

[0033] Figure 9 is a schematic view of an exemplary electrical flange at a distal end of an exhaust pipe; Figure 6

[0034] Figure 10 is a schematic view of a container implementation including an exhaust pipe having a thickened end at the point of attachment to the container; and

[0035] Figure 11 is a cross-sectional view of the thickened portion of the exhaust pipe. DETAILED DESCRIPTION

[0036] Reference will now be made in detail to implementations of the present application; examples of implementations of the present application are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The present application can be embodied in many different forms and should not be construed as limited to the implementations set forth herein.

[0037] As used herein, the terms "about," "approximately," are meant to refer to quantities, dimensions, formulations, parameters, and other quantities and characteristics that are not and need not be exact, but can be approximated and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors that are within the scope of one of ordinary skill in the art.

[0038] Ranges expressed herein as "about," "approximately," from "about" one particular value and / or to "about" another particular value, when reciting such ranges, another implementation includes from the one particular value and to the other particular value. Similarly, when values are expressed as approximations by use of the antecedent "about," it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant, and that the ranges are only meant to be their minimum and maximum values.

[0039] Directional terms as used herein— for example, up, down, right, left, front, back, top and bottom— are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0040] ​Unless specifically stated otherwise, any methods described herein are not inherently related to any particular computer or other apparatus nor are they inherently involved in any particular device. Various embodiments can be implemented in hardware, software, or a combination of both. The various embodiments can be implemented in one or more computer programs or design structures that can be executed over one or more computers. Additionally, such computer programs or design structures can be downloaded to a computer from a website or other remote source via a data communication connection. A website can provide such computer programs or design structures to a user for use on one or more computers. Such website can be one that stores such computer programs or design structures for subsequent download. A website can operate as a service (e.g., an application service provider) for providing software modeling and / or simulation tools, such as tools for use with the various embodiments. A user can employ an appropriate interface to these software tools, which interface can be implemented as part of one or more programs or design structures. One or more programs or design structures can also be implemented in a hardware description language (e.g., HDL) and / or in another functional circuitry. The various embodiments can be implemented in the form, include, but are not limited to, a software routine, a software module, a software application, a software package, a routine, a module, a program, a software program, a script, a computer program, a web application, a web program, an applet, a servlet, an app, or any other type of computer code or design structure.

[0041] 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 with two or more such components unless the context clearly dictates otherwise.

[0042] The words "exemplary," "example," or similar words, as used herein, do not mean "preferred" or "advantageous over other examples or designs." Rather, the words mean an example or illustration by which the disclosure can be better understood. Any aspect or design described herein as "exemplary" or "example" is not necessarily to be construed as preferred or advantageous over other aspects or designs.

[0043] As used herein, the terms "comprises", "comprising", "includes", "including" and the like are to be construed as meaning "including but not limited to", unless otherwise noted. A list of elements following the transitional phrase "comprising" or "including" is non-exclusive, such that additional elements can be present in addition to those specifically listed.

[0044] The term "substantially" and variations thereof as used herein are intended to address values or descriptions that equal or approximately equal a value or description. For example, a "substantially flat" surface is intended to address a surface that is flat or approximately flat. Further, "substantially" is intended to address values that are equal or approximately equal. In some embodiments, "substantially" can address values that are within about 10% of each other, such as within about 5% of each other or within about 2% of each other.

[0045] As used herein, the term "electrically connected" and variants thereof refer to connection by an electrical conductor that does not include a molten material (e.g., molten glass). A first element that is 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 that is electrically connected to a second element should not be interpreted as excluding the presence of additional conductive elements in the connection. In general, such electrical conductors can include metal wiring or cabling and bus bars, among others, without limitation. Electrical connections can also include other components, including but not limited to electrical connectors (e.g., plugs, tabs, lugs, and bolts, among others), that facilitate connections between components, electrical controls (e.g., current and / or voltage controllers), and current and / or voltage measurement devices, among others.

[0046] As used herein, "refractory material" refers to a non-metallic material having chemical and physical properties that make it suitable for use in structures exposed to environments above 538°C or as a component of a system.

[0047] As Figure 1 shown, Figure 1 is an exemplary glass manufacturing apparatus 10. In some embodiments, the glass manufacturing apparatus 10 can include a glass melter 12 that includes a melting vessel 14. In addition to the melting vessel 14, the glass melter 12 can optionally include one or more additional components, such as heating elements (e.g., burners and / or electrodes) configured to heat raw materials and convert the raw materials into molten glass. For example, the melting vessel 14 can be an electrically boosted melter in which energy is added to the raw materials by both burners and by direct heating in which an electric current passes through the raw materials, thereby adding energy to the raw materials in the form of Joule heating.

[0048] In further embodiments, the glass melter 12 can include other thermal management devices (e.g., insulating components) that reduce heat loss from the melter. In still further embodiments, the glass melter 12 can include electronic and / or electromechanical devices that facilitate melting of the raw materials into a glass melt. The glass melter 12 can include support structures (e.g., support floors and support members, among others) or other components.

[0049] The melting vessel 14 can be formed from a refractory material, such as a refractory ceramic material, for example, a refractory ceramic material that includes alumina or zirconia, although other refractory materials, such as yttrium (e.g., yttria, yttria-stabilized zirconia, yttrium phosphate), zircon (ZrSi04), or alumina-zirconia-silica or even chromia, can be used, either alternatively or in any combination. In some examples, the melting vessel 14 can be constructed from refractory ceramic bricks.

[0050] In some embodiments, the glass melter 12 can be incorporated as a component of a glass manufacturing apparatus configured to manufacture, for example, a glass ribbon, although in further embodiments, the glass manufacturing apparatus can be configured to form other glass articles without limitation, such as glass rods, glass tubes, glass envelopes (e.g., for lighting devices such as light bulbs), and glass lenses, although many other glass articles are contemplated. In some examples, the melter can be included in a glass manufacturing apparatus including a slot draw apparatus, a float bath apparatus, a down-draw apparatus (e.g., a fusion down-draw apparatus), an up-draw apparatus, a press apparatus, a rolling apparatus, a tube draw apparatus, or any other glass manufacturing apparatus that would benefit from the present application. For example, Figure 1 The glass melter 12 is schematically shown as a component of a fusion down-draw glass manufacturing apparatus 10 for fusion drawing a glass ribbon for subsequent processing into individual glass sheets or for winding the glass ribbon onto a spool. As used herein, fusion drawing includes flowing molten glass over both side surfaces of a forming body, with the resulting two streams of molten material merging or "fusing" at the bottom of the forming body.

[0051] The glass melter 12 can optionally include an upstream glass manufacturing apparatus 16 upstream of the melting vessel 14. In some examples, a portion or the entire upstream glass manufacturing apparatus 16 can be incorporated as part of the glass melter 12.

[0052] As Figure 1In the illustrated embodiment, 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 can be configured to store a quantity of raw material 24 that can be fed through one or more feed ports into a melting vessel 14 of a glass melter 12, as indicated by arrow 26. Raw material 24 typically includes one or more glass-forming metal oxides and one or more modifiers. In some examples, raw material delivery device 20 can be powered by motor 22 to deliver a predetermined quantity 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 material (hereinafter referred to as “molten glass”) sensed downstream of melting vessel 14, downstream being relative to a direction of flow of molten glass. As used herein, the term “molten glass” refers to any molten material (“melt”) that, when the molten glass cools, can become glass or glass-ceramic (e.g., ceramic phase particles embedded in a glass phase matrix). Raw material 24 in melting vessel 14 can then be heated to form molten glass 28. Typically, in an initial melting step, raw material is added to the melting vessel as particles (e.g., as various “sands”). Raw material 24 can also include scrap glass (i.e., cullet) from previous melting and / or forming operations. A burner is typically used to initiate the melting process. In an electric boost melting process, once the electrical resistance of the raw material is sufficiently reduced, electric boosting can be initiated by creating an electrical potential between electrodes positioned to be in contact with the raw material, thereby establishing an electrical current through the raw material, which typically enters a molten state, or is in a molten state.

[0053] Glass manufacturing apparatus 10 can also optionally include a downstream glass manufacturing apparatus 30 positioned downstream of glass melter 12 relative to a direction of flow of molten glass 28. In some examples, a portion of downstream glass manufacturing apparatus 30 can be incorporated as part of glass melter 12. However, in some cases, first connecting conduit 32 or other portions of downstream glass manufacturing apparatus 30 discussed below, can be incorporated as part of glass melter 12.

[0054] Downstream glass manufacturing apparatus 30 can include a first conditioning chamber, such as fining vessel 34, positioned downstream of melting vessel 14 and coupled to melting vessel 14 by first connecting conduit 32. In some examples, molten glass 28 can be gravity fed from melting vessel 14 to fining vessel 34 through first connecting conduit 32. For example, gravity can drive molten glass 28 through an internal pathway of first connecting conduit 32 from melting vessel 14 to fining vessel 34. Accordingly, first connecting conduit 32 provides a flow path for molten glass 28 from melting vessel 14 to fining vessel 34. However, it should be appreciated that other conditioning chambers can be positioned downstream of melting vessel 14, such as between melting vessel 14 and fining vessel 34. In some embodiments, a conditioning chamber can be employed between a melting vessel and a fining vessel. For example, molten glass from a primary melting vessel can be further heated in a secondary melting (conditioning) vessel, or molten glass from a primary melting vessel can be cooled in a secondary melting vessel to a temperature that is lower than the temperature of the molten glass in the primary melting vessel (melting vessel 14) prior to entering fining vessel 34.

[0055] As previously mentioned, bubbles can be removed from molten glass 28 by various techniques. For example, raw materials 24 can include a multivalent compound, such as tin oxide (i.e., a fining agent), which undergoes a chemical reduction reaction and releases oxygen gas when the fining agent is heated. Other suitable fining agents include, but are not limited to, oxides of arsenic, antimony, iron, and cerium, although the use of oxides of arsenic and antimony can not be encouraged in some applications due to environmental concerns because arsenic and antimony elements are biologically toxic. Fining vessel 34 is heated, for example, to a temperature that is greater than the temperature of melting vessel or the molten glass therein, thereby heating the fining agent. Oxygen gas generated by the temperature-induced chemical reduction of one or more fining agents included in the molten glass enters pre-existing bubbles in the molten glass, causing the bubbles to increase in size. As described in greater detail below, the enlarged bubbles, having increased buoyancy, rise to the free surface of the molten glass within fining vessel and are expelled from the fining vessel.

[0056] The downstream glass manufacturing apparatus 30 may further include another regulating chamber, such as a mixing device 36, for example, a stirring vessel for mixing molten glass flowing downstream from the clarifying vessel 34. The mixing device 36 can be used to provide a homogeneous molten glass composition, thereby reducing chemical or thermal inhomogeneities that may be present in the molten glass leaving the clarifying vessel. As shown, the clarifying vessel 34 may be coupled to the mixing device 36 via a second connecting conduit 38. In some embodiments, the molten glass 28 may be gravity-fed from the clarifying vessel 34 to the mixing device 36 via the second connecting conduit 38. For example, gravity may drive the molten glass 28 through the internal channels of the second connecting conduit 38 from the clarifying vessel 34 to the mixing device 36. Typically, the molten glass within the mixing device 36 comprises a free surface and a free volume extending between the free surface and the top of the mixing device. As used herein, "free surface" refers to the interface between the molten glass and the gaseous atmosphere above the molten glass; that is, the surface of the molten glass. Although the mixing device 36 is shown downstream of the refining vessel 34 in the flow direction relative to the molten glass 28, in other embodiments, the mixing device 36 may be positioned upstream of the refining vessel 34. In some embodiments, the downstream glass manufacturing apparatus 30 may include multiple mixing devices, such as a mixing device upstream of the refining vessel 34 and a mixing device downstream of the refining vessel 34. These mixing devices may be of the same design, or they may be of different designs. In some embodiments, one or more containers and / or conduits including the downstream glass manufacturing apparatus 30 may include static mixing blades positioned therein to facilitate mixing and subsequent homogenization of the molten glass.

[0057] Heating of the clarifying container 34, mixing device 36, and other metal components of the glassmaking equipment (including, but not limited to, the first connecting conduit 32 and the second connecting conduit 38) can occur via direct heating. That is, the electrical flange assembly 40 can be attached to various metal components, wherein the flange assembly 40 is electrically connected to one or more power sources configured to supply current to the electrical flange assembly 40. Current flows through the walls of the metal components (e.g., containers and conduits) between the flange assemblies 40, thereby heating the walls of the metal components by Joule heating, and subsequently heating the molten material 28 flowing through them. A more detailed discussion of the flange assembly is provided below.

[0058] In some implementations, the second connecting conduit 38 may include more than one segment. For example, such as Figure 2As shown, the second connecting conduit 38 can include a first conduit segment 38a that includes a proximal end 42, a distal end 44 opposite the proximal end 42, and a passageway 46 extending between the proximal end 42 and the distal end 44. The proximal end 42 is connected to the fining vessel 34. The second connecting conduit 38 can further include a second conduit segment 38b that includes a proximal end 48, a distal end 50, and a passageway 52 extending between the proximal end 48 and the distal end 50. The proximal end 48 can be connected to the mixing apparatus 36 (e.g., a mixing vessel). The first conduit segment 38a can be rigidly connected to the outlet of the fining vessel 34 by welding at the proximal end 42 of the first conduit segment 38a. Similarly, the second conduit segment 38b can be rigidly connected to the inlet of the mixing apparatus 36 by welding at the proximal end 48 of the second conduit segment 38b. In addition, the distal end 44 of the first conduit segment 38a can be coupled to the distal end 50 of the second conduit segment 38b. For example, in various embodiments, the first conduit segment 38a can include a first electrical flange assembly 40a attached to the distal end 44, and the second conduit segment 38b can include a second electrical flange assembly 40b attached to the distal end 50, with the first and second conduit segments 38a, 38b arranged such that a gap 54 is formed between the first and second electrical flange assemblies 40a, 40b. The gap 54 can be, for example, in a range from about 1 mm to about 1 cm. When molten glass 28 is being conveyed through the first and second conduit segments 38a, 38b, molten glass can seep into the gap 54. Exposing the molten glass in the gap to a cooler environment outside the gap causes the molten glass therein to cool, thus increasing the viscosity of the molten glass and plugging the gap, preventing further leakage of molten glass. Such plugging is referred to as a "glass seal." The glass seal can accommodate small misalignments or movements of the coupled components, such as during temperature changes, and can electrically isolate the first and second conduit segments 38a, 38b and allow independent direct heating.

[0059] The first and second electrical flange assemblies 40a, 40b are configured to allow current to enter or exit the respective first or second conduit segments 38a, 38b. For example, in some embodiments, the fining vessel 34 can include a third electrical flange assembly 40c positioned at or near the junction between the proximal end 42 of the first conduit segment 38a and the fining vessel 34. Thus, the first and third electrical flange assemblies 40a, 40c can be electrically connected to a power source 56a that can supply current to the first conduit segment 38a through the first and third electrical flange assemblies 40a, 40c. The supplied current can thus heat the first conduit segment 38a by direct heating according to the electrical resistance of the wall(s) of the first connecting conduit portion. While the first power source 56a is shown as being directly connected to the electrical flange assemblies 40a, 40c, in further embodiments, the first power source 56a can be an indirect electrical connection. For example, the first power source 56a can include a transformer, where one side of the transformer winding (e.g., the primary winding) can be electrically connected to the power service of the facility housing the glass manufacturing apparatus, and the other side of the transformer winding (e.g., the secondary winding) can be electrically connected to the first and third electrical flange assemblies 40a, 40c through winding taps. The electrical flange assemblies 40a-40c each include a body portion 58 that encircles and is attached to the respective conduit or vessel portion to which it is attached, and one or more electrode portions 60 that extend from the body portion and provide attachment points for electrical cables or busbars that provide current to the flange assemblies. While not shown, in various embodiments, the electrical flange assemblies can include one or more rings (e.g., concentric rings) of different materials, different thicknesses, and / or different radial widths to control the distribution of current around the flange assembly and into the respective conduit or vessel.

[0060] While the fining vessel 34 is typically arranged such that its length is horizontal or substantially horizontal (e.g., within 10° of horizontal), as shown in FIG. 1, in some embodiments, the fining vessel 34 can be arranged such that its length is vertical or substantially vertical (e.g., within 10° of vertical). For example, as shown in FIG. 2, the fining vessel 34 can be arranged such that its length is vertical or substantially vertical, and the first and second electrical flange assemblies 40a, 40b can be positioned at or near the proximal end 42 of the first conduit segment 38a and the distal end 44 of the second conduit segment 38b, respectively. Thus, the first and second electrical flange assemblies 40a, 40b can be electrically connected to a power source 56b that can supply current to the first and second conduit segments 38a, 38b through the first and second electrical flange assemblies 40a, 40b. The supplied current can thus heat the first and second conduit segments 38a, 38b by direct heating according to the electrical resistance of the wall(s) of the first and second connecting conduit portions. Figure 2As shown, the first conduit segment 38a can include a first conduit portion 38al that is arranged horizontally or substantially horizontally, and a second conduit portion 38a2 that is angled β downward from the first conduit portion 38al along the longitudinal axis 62 of the segment (e.g., relative to horizontal). As described herein, an axis that extends in a downward direction relative to horizontal and the direction of the local molten glass flow (e.g., direction 63) will be considered to extend at a negative angle, while an axis that extends in an upward direction relative to horizontal and the direction of the local molten glass flow (e.g., direction 63) will be considered to extend at a positive angle. Thus, the longitudinal axis 62 can form a negative angle β relative to a horizontal axis 64. The downward inclination of the conduit portion 38a2 will be positioned by the glass seal 66 to the second conduit segment 38b of the first conduit segment 38a completely below the plane defined by the free surface 68 of the molten glass 28 in the fining vessel 34. That is, in operation, the molten glass 28 conveyed through the fining vessel 34 is maintained at a level such that the free surface 68 of the molten glass in the fining vessel forms a "free volume" 70 within the fining vessel defined between the free surface 68 of the molten glass 28 and the fining vessel 34. The free volume 70 is free of molten glass and contains a first atmosphere 72 that provides space for the accumulation of volatile gases and other materials that can be released from the molten glass. For example, certain components of the molten glass, such as boron, can readily evaporate from the free surface of the molten glass. In addition, various gases produced during the melting process can be released from the free surface. As described below, the first atmosphere can be vented to a second atmosphere 74 (e.g., the ambient atmosphere surrounding the glass manufacturing apparatus 10) outside of the fining vessel. In addition, the free volume 70 is continuous within at least a portion of the first conduit portion 38al (e.g., proximate the fining vessel 34) and also includes the first atmosphere 72. The height (vertical position) of the free surface 68 of the molten material is referred to as the "glass line," a term that can be used interchangeably herein with molten glass level. The glass line can be considered the height of the inner surface of the molten glass wetted inner surface of the conduit inner wall surface.

[0061] Positioning the second conduit segment 38b below the glass line, and in particular below the minimum expected glass line, can minimize the capture of gases contained in the first atmosphere 72 into the molten glass. The second conduit portion 38b is positioned sufficiently below the glass line such that normal shifts in the glass line up or down do not result in a free volume within the second conduit segment 38b.

[0062] As Figure 2Further, additional flange assemblies can be provided. For example, a fourth electrical flange assembly 40d can be attached to the second conduit segment 38b downstream of the second electrical flange assembly 40b, where the second electrical flange assembly 40b and the fourth electrical flange assembly 40d are electrically connected to the second power supply 56b. Current provided by the second power supply 56b passes through the walls of the second conduit segment 38b through the second electrical flange assembly 40b and the fourth electrical flange assembly 40d. Similarly, a fifth electrical flange assembly 40e can be attached to the mixing apparatus 36 and electrically connected to the third power supply 56c, where the electrical flange assemblies 40d and 40e supply current through the third power supply 56c through the second conduit segment 38b and portions of the mixing apparatus 36. Additional electrical flange assemblies 40 can be provided on the mixing apparatus 36 and the fining vessel 34. In some embodiments, multiple flange assemblies 40 and multiple power supplies 56 can be provided on the fining vessel 34 and other components of the downstream glass manufacturing apparatus 30, and the multiple flange assemblies 40 and multiple power supplies 56 can define multiple individually controlled heating zones. Each heating zone can be provided with current of the same or different current magnitude and phase as desired to achieve a predetermined temperature in the individual temperature zone. For example, in some embodiments, it can be desirable to cool the molten glass flowing through the second connecting conduit 38 prior to entering the mixing apparatus 36. Accordingly, the current magnitude in the first conduit segment 38a can be controlled to be less than the current magnitude in the second conduit segment 38b, such that the temperature of the second conduit segment 38b is lower than the temperature of the first conduit segment 38a, thereby cooling the molten glass as it flows through the first conduit portion 38a and the second conduit portion 38b.

[0063] Returning to Figure 1 The downstream glass manufacturing apparatus 30 can further include another conditioning chamber, such as a delivery vessel 80 located downstream of the mixing apparatus 36. The delivery vessel 80 can condition the molten glass 28 for feeding to downstream forming devices. For example, the delivery vessel 80 can act as an accumulator and / or flow controller to regulate a consistent flow of the molten glass 28 and provide it through an outlet conduit 84 to a forming body 82. In some embodiments, the molten glass within the delivery vessel 80 can include a free surface, where a free volume extends upward from the free surface to a top of the delivery vessel. As shown, the mixing apparatus 36 can be coupled to the delivery vessel 80 by a third connecting conduit 86. In some examples, the molten glass 28 can be gravity fed from the mixing apparatus 36 to the delivery vessel 80 through the third connecting conduit 86. For example, gravity can drive the molten glass 28 through an internal passage of the third connecting conduit 86 from the mixing apparatus 36 to the delivery vessel 80.

[0064] The downstream glass manufacturing apparatus 30 can further include a forming apparatus 88 including the forming body 82 described above, which includes an inlet conduit 90. The outlet conduit 84 can be positioned to deliver the molten glass 28 from the delivery vessel 80 to the inlet conduit 90 of the forming apparatus 88. The forming body 82 in a molten down-draw glass manufacturing apparatus can include a trough 92 positioned in an upper surface of the forming body and converging forming surfaces 94 (only one surface shown) that converge in a draw direction along a bottom edge (root) 96 of the forming body, where the converging surfaces define the root. The molten glass delivered to the forming body trough 92 through the delivery vessel 80, outlet conduit 84, and inlet conduit 90 overflows the walls of the forming body trough 92 and descends along the converging forming surfaces 94 as individual streams of molten glass. The individual streams of molten glass converge below and along the root 96 to produce a single ribbon of molten glass 98 that is drawn from the root 96 in a draw plane in a draw direction 100 by applying a downward tension to the ribbon, such as by gravity and / or a pull roll assembly (not shown), to control the dimensions of the ribbon as the molten glass cools and the viscosity of the molten glass increases. As a result, the ribbon 98 undergoes a viscoelastic transition to an elastic state and acquires mechanical properties, thereby providing the ribbon 98 with stable dimensional properties. In some embodiments, the resulting ribbon of glass 98 can be separated into individual glass sheets 102 by a glass separation apparatus (not shown), while in other embodiments, the ribbon of glass can be wound onto a spool and stored for further processing.

[0065] The components of the downstream glass manufacturing apparatus 30, including any of the connecting conduit 32, the connecting conduit 38, the connecting conduit 86, the fining vessel 34, the mixing apparatus 36, the delivery vessel 80, the outlet conduit 84, or the inlet conduit 90, can be formed from a noble metal. Suitable noble metals include platinum group metals selected from the group consisting of platinum, iridium, rhodium, osmium, ruthenium, and palladium, or alloys of the foregoing. For example, the downstream components of the glass manufacturing apparatus can be formed from a platinum-rhodium alloy including about 70% to about 90% by weight platinum and about 10% to about 30% by weight rhodium. However, other suitable metals for forming the downstream components of the glass manufacturing apparatus can include molybdenum, rhenium, tantalum, titanium, tungsten, and alloys thereof.

[0066] Although the elements of the glass manufacturing apparatus 10 are shown and described as molten down-draw glass manufacturing elements, the principles of the present application can be applied to a variety of glass manufacturing processes. For example, the furnaces according to embodiments of the present application can be used in a variety of glass manufacturing processes such as fusion processes, slot draw processes, rolling processes, pressing processes, float processes, tube drawing processes, and the like.

[0067] As noted above, gas bubbles are removed from the molten material in the fining vessel 34. These gas bubbles include, but are not limited to, those formed from gases trapped in the particulate bed of raw materials and / or cullet introduced into the melting system as those materials to be melted, gases produced by chemical dissolution or reaction of the raw materials throughout the melting process, and gases produced by reaction with other materials (such as refractory materials or metallic components) during the process. The gas bubbles can include, for example, gases such as oxygen, nitrogen, water vapor, argon, sulfur dioxide, and carbon dioxide. In addition, in various embodiments, a gas can be intentionally introduced into the fining vessel (e.g., into the free volume 70) through the gas supply pipe 104 to aid in the fining process (see, e.g., U.S. Patent No. 6, 1 12, 820, which is incorporated herein by reference in its entirety). Such intentionally introduced gases can include nitrogen, helium, or other inert gases or combinations thereof. Water can be introduced in the form of a vapor, and can be combined with an inert gas (e.g., a humidified gas). In addition, the high temperatures present in the fining vessel components (in some cases approaching or exceeding 1700°C) can cause one or more components of the molten glass (e.g., boron, sodium, and / or tin) to vaporize. Figure 3

[0068] According to embodiments described herein, a blanket gas 106 can be injected into the free volume 70 above the free surface 68 through the fining vessel gas supply pipe 104. In some embodiments, the blanket gas 106 can be a humidified blanket gas. The humidified blanket gas 106 includes water vapor and oxygen (O2), and can further include a non-flammable carrier gas. As used herein, a non-flammable carrier gas does not include hydrocarbons and / or is not formed as a byproduct of combustion in a glass manufacturing process, and can include, for example, an inert gas such as nitrogen; although in further embodiments, the carrier gas can be another inert gas, such as, for example, helium, neon, argon, krypton, xenon, etc., or a combination of any of the foregoing inert gases. For example, in embodiments, none of the components of the carrier gas or humidified gas are typically derived from an immersion burner (e.g., a melting vessel) in a glass manufacturing process that relies on combustion of a fuel, such as a natural gas, as a source of moisture (e.g., water vapor).

[0069] The average oxygen (O2) content of the humidified blanket gas 106 should be equal to or greater than the oxygen content in the gas bubbles to ensure that oxygen does not diffuse outward from the gas bubbles. That is, the oxygen partial pressure in the atmosphere outside the gas bubble should be at least equal to the oxygen partial pressure inside the gas bubble. Diffusion of oxygen outward from the gas bubble into the surrounding atmosphere causes the gas bubble to shrink and subsequently thicken the gas bubble wall. The thickened gas bubble wall can lengthen the gas bubble burst time, sufficient to allow the gas bubble to be re-entrained in the molten glass stream. Thus, in some embodiments, the oxygen partial pressure within the humidified gas can be greater than the oxygen partial pressure in the gas bubbles to ensure that the gas bubbles expand.

[0070] ​The average oxygen content of the humidified blanket gas 106 can be, for example, in the range of about 10% to about 90% by volume, for example, in the range of about 15% to about 90% by volume, in the range of about 20% to about 90% by volume, in the range of about 30% to about 90% by volume, in the range of about 40% to about 90% by volume, in the range of about 50% to about 90% by volume, in the range of about 60% to about 90% by volume, in the range of about 70% to about 90% by volume, in the range of about 80% to about 90% by volume, in the range of about 10% to about 80% by volume, in the range of about 10% to about 70% by volume, in the range of about 10% to about 60% by volume, in the range of about 10% to about 50% by volume, in the range of about 10% to about 40% by volume, in the range of about 10% to about 30% by volume, or in the range of about 10% to about 20% by volume, including all ranges and subranges therebetween. In some embodiments, the humidified blanket gas 106 can comprise air.

[0071] In some embodiments, the presence of water vapor as a surfactant can counteract the effect of the oxygen partial pressure outside the bubble wall being lower than the oxygen partial pressure inside the bubble wall. Thus, it should be understood that the goal is to prevent bubble shrinkage, which would thicken the bubble wall and prolong the bubble duration (delay bubble collapse). Thus, the amounts of oxygen and water vapor can be adjusted to prevent bubble shrinkage, which in some embodiments can result in the oxygen partial pressure outside the bubble being less than the oxygen partial pressure inside the bubble.

[0072] The dew point of the humidified blanket gas 106 can be in the range of about 41 °C to about 92 °C, for example, in the range of about 60 °C to about 92 °C. The remaining humidified blanket gas can be an inert carrier gas.

[0073] The flow rate of the humidified blanket gas 106 can range from greater than 0 to about 80 standard liters per minute (slpm), such as in a range from about 10 slpm to about 80 slpm, in a range from about 20 slpm to about 80 slpm, in a range from about 30 slpm to about 80 slpm, such as in a range from about 40 slpm to about 80 slpm, in a range from about 50 slpm to about 80 slpm, in a range from about 60 slpm to about 80 slpm, in a range from about 70 slpm to about 80 slpm, in a range from about 10 slpm to about 70 slpm, in a range from about 10 slpm to about 60 slpm, in a range from about 10 slpm to about 50 slpm, in a range from about 10 slpm to about 40 slpm, in a range from about 10 slpm to about 30 slpm, or in a range from about 10 slpm to about 20 slpm.

[0074] In some embodiments, the clarified container gas supply tube 104 can be heated, thereby heating the humidified blanket gas supplied to the clarified container 34. For example, the clarified container gas supply tube 104 and the humidified blanket gas 106 therefrom can be heated by one or more heating elements 107, such as an external electrical resistance heating element(s) 107; although in further embodiments, the clarified container gas supply tube 104 can be heated directly by establishing an electrical current directly within the clarified container gas supply tube in a manner similar to that described for heating the clarified container 34. For example, the clarified container gas supply tube 104 can include one or more electrical flange assemblies 40 in electrical communication with a power source as described with respect to the clarified container 34.

[0075] In accordance with other embodiments described herein, a dry blanket gas 106 can be injected through the clarified container gas supply tube 104 into the free volume 70 above the free surface 68. In various embodiments, the dry blanket gas 106 can include a relative humidity equal to or less than about 1%, such as equal to or less than about 0.5%, equal to or less than about 0.1%, or equal to or less than about 0.05%, such as zero percent (0%), and the dry blanket gas 106 can further include an inert gas, such as nitrogen; although in further embodiments, the inert gas can be an inert gas such as helium, neon, argon, krypton, xenon, or the like, or a combination of any of the foregoing inert gases.

[0076] The average oxygen (02) content of the dry blanket gas 106 supplied to the fining vessel 34 should be less than the oxygen content in the bubble to ensure outward diffusion of oxygen from the bubble. That is, the partial pressure of oxygen in the blanket gas outside the bubble should be less than the partial pressure of oxygen inside the bubble. For example, in various embodiments, the dry blanket gas 106 supplied to the fining vessel 34 can include an 02 content equal to or less than 0.2 vol.%, for example, in a range of about 0.05 vol.% to about 0.2 vol.%, such as about 0.075 vol.% to about 1.5 vol.%. There should be enough oxygen in the blanket gas to prevent reduction of the platinum-containing walls of the fining vessel due to the high nitrogen concentration in the blanket gas. However, the concentration of oxygen should be low enough to prevent destructive oxidation of the platinum-containing walls at high temperatures. Thus, in various embodiments, the dry blanket gas 106 can be primarily nitrogen (> 50 vol.%) including oxygen in a range of about 0.05 vol.% to about 0.2 vol.% and including a relative humidity equal to or less than about 0.5%. In other embodiments, the dry blanket gas 106 can be primarily nitrogen including oxygen in a range of about 0.075 vol.% to about 0.15 vol.% and including a relative humidity equal to or less than about 0.1%. In other embodiments, the dry blanket gas 106 can be primarily nitrogen including oxygen in a range of about 0.075 vol.% to about 0.15 vol.% and including a relative humidity equal to or less than about 0.05%. In some embodiments, the dry blanket gas 106 can include N2 at a concentration equal to or greater than 78 vol.%, for example, equal to or greater than about 85 vol.%, equal to or greater than about 90 vol.%, equal to or greater than about 95 vol.%, equal to or greater than about 98 vol.%, or equal to or greater than about 99.8 vol.%.

[0077] The low-oxygen, low-humidity atmosphere provided to the free volume 70 by the dry blanket gas 106 can create a net flow of gas and / or vapor from within the bubble on the surface of the molten glass 28 within the fining vessel 34 through the bubble membrane into the free volume 70, where, as previously described, the released gas and / or vapor (e.g., water vapor) can exit the free volume 70 through the exhaust. The release of gas and / or vapor diffusing through the bubble membrane from the bubble can cause the bubble to shrink. The shrinkage can make the bubble too small to be re-entrained in the molten glass stream, allowing the bubble more time to break. In some embodiments, this shrinkage can result in complete breakage of the bubble.

[0078] The flow rate of the cover gas 106 can range from equal to or greater than about 1 turnover per minute to equal to or less than about 1 turnover per hour, including all ranges and subranges therebetween. As used herein, "turnover" refers to a flow rate equivalent to the volume of free volume per unit time. For example, for a one liter volume, one turnover per minute means a gas flow rate equal to one liter per minute. Gas supplied at a rate of two turnovers per minute to a four liter volume means a flow rate of eight liters per minute. The flow rate selected will depend on the size of the free volume supplied with cover gas. The flow rate of the cover gas can range, for example, from about 0.02 turnovers per minute to about 1 turnover per minute, from about 0.05 turnovers per minute to about 1 turnover per minute, from about 0.1 turnovers per minute to about 1 turnover per minute, from about 0.5 turnovers per minute to about 1 turnover per minute, or from about 0.8 turnovers per minute to about 1 turnover per minute, including all ranges and subranges therebetween.

[0079] In some embodiments, a predetermined concentration of a non-reactive gas, such as an inert gas like argon, krypton, neon, or xenon, or another non-reactive gas, can be added to the cover gas 106, such as a cover gas injected into the free volume of a fining vessel or other vessel, such as the mixing apparatus 36, as a means of identifying the source of a bubble in a finished glass article resulting from the glass manufacturing process. That is, a bubble in the molten glass can be labeled with a detectable amount of a non-reactive gas as a means of determining the location of bubble formation. For example, a particular first non-reactive gas (hereinafter referred to as a "marker" gas) can be added to the cover gas 106 supplied to a fining vessel 34, such as a gas mixing chamber in fluid communication with a corresponding vessel gas supply line, such as the fining vessel gas supply line 104. Suitable marker gases can include, but are not limited to, argon, krypton, neon, helium, and xenon.

[0080] Bubbles (blisters) found in finished glass articles can be analyzed, e.g., by mass spectrometry, to determine if the first marker gas is present in the bubbles at a concentration consistent with the concentration of the first marker gas added to the cover gas supplied to the fining vessel 34, thereby identifying the fining vessel as the source of the bubbles. However, a marker gas concentration found in the bubbles that is not consistent with the concentration of the marker gas supplied to the fining vessel 34 can indicate that the source of the bubbles is not the fining vessel. Similarly, a second marker gas different from the first marker gas can be added to the cover gas supplied to a different vessel, e.g., the mixing apparatus 36. Analysis of the bubbles in the glass articles can then be used to determine the number of bubbles containing the first marker gas, if any, and / or the number of bubbles containing the second marker gas, if any, thereby better identifying and quantifying the source of the bubbles. For example, if the second marker gas is found, but not the first marker gas, it can be concluded that the source of the bubbles is from the vessel that has taken up the second marker gas. The presence of both the first and second marker gases in the bubbles can indicate that the bubbles survived transport between several vessels and resided on the surface of the molten glass in two vessels.

[0081] The one or more marker gases are typically not the primary gas comprising the cover gas. For example, if the primary gas (>50%) comprising the cover gas 106 is N2, the cover gas can comprise less than 50% of the marker gas, where the marker gas is different from the primary gas.

[0082] Figure 3 and Figure 4 An exemplary lower portion of the fining vessel gas supply tube 104 is depicted, which passes through the wall 120 of the fining vessel 34 above the free surface 68 of the molten glass 28. Figure 3 and Figure 4 The fining vessel gas supply tube 104 can extend through a reinforcing sleeve 122 where the fining vessel gas supply tube 104 passes through the wall 120 of the fining vessel. Further, in the cross-sectional view of Figure 4The stiffening plates 124 are depicted as encircling and being located above and / or below the wall 120 of the fining vessel and attached to the wall 120 of the fining vessel. The stiffening plates 124, the stiffening sleeve 122, and the wall 120 of the fining vessel can be attached to one another, such as by welding. For example, the stiffening plates 124 can be welded to the wall 120 of the fining vessel and the stiffening sleeve 122. Additionally, in embodiments, the stiffening sleeve 122 can be welded to the fining vessel gas supply tube 104. The stiffening plates 124 and the stiffening sleeve 122 provide additional thickness to the wall of the fining vessel and the fining vessel gas supply tube 104, as both can be formed from a sheet of platinum alloy and both are susceptible to deformation as the metal expands during initial heating of the system. The additional thickness can provide greater strength to the gas supply tube as it passes through the wall of the fining vessel, and the additional thickness can reduce heating through the area by reducing the current (and thus the resistance) through the joint in the event that the gas supply tube is directly heated.

[0083] The fining vessel gas supply tube 104 can include a closed bottom 126 and a gas outlet 128 located on a sidewall of the fining vessel gas supply tube 104, proximate to the bottom of the fining vessel gas supply tube and oriented such that the cover gas 106 is discharged from the fining vessel gas supply tube 104 in a direction substantially parallel to the direction of flow 130 of the molten glass in the fining vessel 34, such as oriented in a downstream direction. Substantially parallel flow of the cover gas 106 and the molten glass 28 minimizes or eliminates direct impingement of the cover gas discharged from the gas supply tube on the surface of the molten glass and subsequent cooling of the surface of the molten glass. Such cooling can result in non-uniform viscosity in the molten glass, which can manifest as defects in the final product. Additionally, the laterally open fining vessel gas supply tube 104 can reduce the likelihood of condensate, such as volatile glass constituents like boron, accumulating in the gas outlet and ultimately falling into the molten glass below.

[0084] As a result of the above-described processing, a first atmosphere 72 contained within the free volume 70 and extending along at least a portion of the length of the fining vessel 34 and the first conduit segment 38a can include any one or more of the aforementioned gases and vapors, and such atmosphere should be exhausted from the fining vessel. Typically, the exhaust of the fining vessel 34 occurs through an exhaust tube extending from the top of the fining vessel. However, such a configuration can produce undesirable results. For example, volatile materials evaporated from the molten glass can condense on the interior surface of the exhaust tube. If a sufficient amount of condensate accumulates, the condensate can break off and fall into the underlying molten glass, thereby contaminating the molten glass. Furthermore, it is difficult to clean a straight exhaust tube extending from the top of the fining vessel without discharging condensate that falls through the exhaust tube and contaminates the underlying molten glass. Past efforts to mitigate contamination have included forming a bend in the exhaust tube that is sharply bent when initially rising vertically from the fining vessel, so that the discharged condensate will not fall into the fining vessel. However, such a sharp bend makes it difficult to clean the exhaust tube beyond the bend (e.g., between the bend and the fining vessel) from outside the fining vessel, as cleaning tools cannot reach beyond the bend from the outlet of the exhaust tube.

[0085] To overcome the foregoing problems, embodiments of improved exhaust apparatus are described. Thus, in some embodiments, the diameter of the first conduit segment 38a can be enlarged compared to conventional connecting conduits. Referring to Figure 5 and Figure 6 , the large diameter conduit can provide an increased free volume 70, thereby enabling the exhaust tube 200 to be placed proximate the top 202 of the first conduit portion 38a but sufficiently above the free surface of the molten glass 28 to prevent the molten glass 28 from entering the exhaust tube 200. For example, the inlet of the exhaust tube 200 can be positioned at least 2.5 cm above the glass line. Referring to Figure 6 , a cross-sectional view is shown taken along line 6-6 of Figure 5 , in various embodiments, the connection between the exhaust tube 200 and the first conduit segment 38a can be positioned at an angle ranging from about 5° to about 60° relative to vertical, such as in a range of about 10° to about 45°, where 0° is the position at the vertical top of the first conduit segment 38a (i.e., the 12 o'clock position).

[0086] In some embodiments, the top of the first conduit portion 38a can be higher than the top of the fining vessel 34 relative to the bottom 204 of the fining vessel 34. The exhaust tube 200 can be a straight exhaust tube that extends from a proximal end 206 along a central longitudinal axis 208 downward at a negative angle a relative to horizontal and terminates at a distal end 210, the exhaust tube defining a passageway 212 therethrough (see Figure 11As shown, none of the portions of the exhaust tube 200 extend vertically or at any positive angle above horizontal from the proximal end 206. The angle a can be in a range of greater than 0° to less than 90°, such as in a range of about 3° to about 80°, in a range of about 3° to about 40°, in a range of about 3° to about 20°, or in a range of about 3° to about 10°. Thus, the exhaust tube 200 provides fluid communication between the free volume 70 proximate the top of the first conduit segment 38a, and further provides sufficient distance between the free surface 68 of the molten glass 28 and the bottom of the proximal end 206 of the exhaust tube 200 to accommodate upward deflection of the glass line without clogging the exhaust tube. During operation of the glass manufacturing apparatus, the first atmosphere 72 remains in fluid communication with the second external atmosphere 74 through the exhaust tube 200. At the same time, the exhaust tube 200 provides a passageway from the outer second conduit 38 (e.g., the first conduit segment 38a) through the entire length of the exhaust tube, thereby facilitating ease of cleaning without risk of particulates falling into the molten glass 28.

[0087] Referring to Figure 7 In other embodiments, it can not be necessary to enlarge the entirety of the first conduit segment 38a. Instead, a portion of the first conduit segment 38a can be enlarged upward, creating a large domed portion 214 above the free surface 68 of the molten glass 28 within the first conduit segment 38a. In some embodiments, the domed portion 214 can extend above the fining vessel 34. That is, the top of the domed portion 214 can extend vertically upward from the bottom of the fining vessel 34 a greater distance dl than the distance d2 of the top of the fining vessel 34. As before, the exhaust tube 200 can be a straight exhaust tube that connects at the proximal end 206 to the domed portion 214 and extends from the proximal end 206 along the central longitudinal axis 208 at a negative angle a relative to horizontal downward from the proximal end 206, the exhaust tube 200 terminating at the distal end 210. As before, none of the portions of the exhaust tube 200 extend vertically or at any positive angle above horizontal from the proximal end 206. The angle a can be in a range of greater than 0° to less than 90°, such as in a range of about 3° to about 80°, in a range of about 3° to about 40°, in a range of about 3° to about 20°, or in a range of about 3° to about 10°.

[0088] The large, upwardly extending dome portion 214 allows sufficient distance between the free surface 68 of the molten glass 28 and the bottom of the proximal end 206 of the vent 200 to accommodate upward displacement of the glass line during operation of the glassmaking equipment. In other words, the free volume 70 of the clarifying vessel 34 extends into the first conduit segment 38a, and the inlet of the vent 200 is positioned on the first conduit segment 38a (e.g., the dome portion 214) such that the proximal end 206 of the vent 200 is positioned above the intended maximum height of the glass line to prevent upward displacement of the molten glass from blocking the vent during operation of the glassmaking equipment. For example, the inlet of the vent 200 may be positioned at least 2.5 cm above the glass line.

[0089] Although the clarifying container 34 is shown as having a circular cross-section in a plane orthogonal to the central longitudinal axis 216 of the clarifying container, in a further embodiment, the clarifying container 34 may include a non-circular cross-sectional shape, such as a rectangular cross-sectional shape. Similarly, the exhaust pipe 200 may have a non-circular cross-sectional shape.

[0090] Similar to along Figure 5 Line 6-6 looking back Figure 6 The arrangement shown in some embodiments follows... Figure 7 Line 8-8 looking back Figure 8 As shown, the exhaust pipe 200 may include an electrical flange 220. The electrical flange 220 is configured to extend completely around the exhaust pipe 200 at or near its distal end 210, and may include an extension 222 serving as a connection point for cables, busbars, or other electrical conductors, such as an electrode portion. The electrical flange 220 may include a single homogeneous element and may include, for example, a platinum-containing material, such as a platinum-rhodium alloy. In any of the foregoing embodiments, the exhaust pipe 200 may have the electrical flange 220 fitted at its distal end 210, wherein a power source may provide current between the electrical flange 220 and one or both of the first electrical flange assembly 40a and / or the third electrical flange assembly 40c. In some embodiments, the power source may include an additional secondary winding of the first power source 56a or a tap from a single secondary winding. Therefore, the exhaust pipe 200 can be directly heated by current in the walls of the exhaust pipe. That is, the exhaust pipe can be used as a heating element. Figure 10 and Figure 11 As shown, in various embodiments, the wall of the exhaust pipe 200 at and / or near the proximal end 206 (in which the exhaust pipe 200 is attached to the first conduit segment 38a) may be made thicker than the wall at the distal end 210, or thicker than the exhaust pipe wall located at an intermediate position between the proximal end 206 and the distal end 210. For example, the proximal end 206 may include multiple layers.

[0091] Figure 11An embodiment of the proximal end 206 is shown, which includes a first inner layer 224 and a second outer layer 226. The inner layer 224 can be the exhaust tube itself extending from the proximal end 206 to the distal end 210, with the second layer 226 being a cladding layer disposed on the exhaust tube at the proximal end 206. In such a manufacturing implementation, the second layer 226 can be attached to the exhaust tube 200 by welding. The thicker proximal end can strengthen the attachment area of the exhaust tube 200 where the exhaust tube is attached to the clarifying vessel 34 and can help control the current flow through the attachment point, avoiding hot spots that can degrade the connection. Thus, in some embodiments, the thickness of the thickened portion of the proximal end 206 can vary circumferentially as needed to distribute the current flow evenly around the circumference of the exhaust tube at the proximal end 206. Similarly, the area of the first conduit segment 38a at the attachment of the exhaust tube 200 can also be thickened relative to the area away from the exhaust tube to strengthen the connection point and aid in the distribution of current flow. The wall of the connection conduit 38 at the attachment point of the exhaust tube 200 can also be thickened, such as by the attachment of a reinforcement plate(s) 228, for example by welding. In some embodiments, the distal end 210 of the exhaust tube 200, where the electrical flange 220 is connected to the exhaust tube, can be thickened by attaching a sleeve around the exhaust tube at the distal end 210 in a similar manner to the proximal end 206.

[0092] In further embodiments, the exhaust tube 200 can be heated by radiative and / or conductive heat from a separate heating element (such as a heating coil) located in proximity to the exhaust tube. For example, in some embodiments, a heating element can be coiled around the exhaust tube but spaced apart from the exhaust tube. In some embodiments, multiple heating elements can be positioned at different locations around the circumference of the exhaust tube 200. To maintain the temperature of the exhaust tube, a thermal insulation material (not shown), such as a ceramic insulation material, can be wrapped around the exhaust tube 200, for example.

[0093] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present application without departing from the spirit and scope of the application. Thus, it is intended that the present application cover the modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A method for manufacturing glass articles, comprising: Molten material is allowed to flow through a first container to a second container downstream of the first container, the molten material flowing through a conduit connecting the first container to the second container, the first container and the conduit defining a continuous free volume above the free surface of the molten material, the free volume extending into at least a portion of the conduit; as well as A first atmosphere contained in the free volume is discharged to a second atmosphere outside the first container via an exhaust pipe, the exhaust pipe including a proximal end, a distal end opposite the proximal end, and a channel extending between the proximal end and the distal end, the proximal end being close to the top of the conduit and connected to the conduit above the free surface, the exhaust pipe extending downward and away from the conduit along a longitudinal axis at an angle α relative to the horizontal plane and providing fluid communication between the first atmosphere and the second atmosphere. The first portion of the conduit extends horizontally from the first container, and the vent pipe is connected to the first portion of the conduit. Wherein, at least one second portion of the catheter extends downward and inclined from the first portion of the catheter at an angle β relative to the horizontal plane.

2. The method of claim 1, wherein the exhaust pipe is straight between the proximal end and the distal end.

3. The method of claim 1, wherein the angle α is in the range from greater than 0° to less than 90°.

4. The method of claim 3, wherein the angle α is in the range of 3° to 10°.

5. The method of claim 1, further comprising: The exhaust pipe is heated during the emission process.

6. The method of claim 5, wherein the heating comprises: An electric current is established in the heating element.

7. The method of claim 6, wherein the heating element comprises the wall of the exhaust pipe.

8. The method of claim 5, wherein the heating comprises: Current is established between a first electrical flange connected to the exhaust pipe and a second electrical flange connected to at least one of the first container or the conduit.

9. The method of claim 1, further comprising: The molten material is allowed to flow into the forming body, and the molten material is formed into a glass ribbon.

10. The method of claim 9, wherein the forming comprises: The molten material is pulled downward from the forming body.

11. The method of claim 1, wherein the first container is a clarification container and the second container is a mixing container.

12. The method of claim 1, wherein the method comprises: A predetermined distance is provided between the free surface of the molten material and the bottom of the proximal end of the exhaust pipe to accommodate the upward offset of the glass line.

13. The method of claim 1, further comprising: The covering gas flows into the free volume through a gas delivery pipe connected to the first container.

14. The method of claim 1, further comprising: The conduit is heated while the molten material is flowing through it.

15. The method of claim 1, wherein the thickness of the wall of the conduit varies along the length of the conduit.

16. The method of claim 1, wherein, In a cross-section of the conduit orthogonal to its longitudinal axis, the thickness of the conduit wall in a first portion of the cross-section is different from the thickness of the conduit wall in a second portion of the cross-section.

17. A method of manufacturing a glass article, comprising: Molten material is allowed to flow from a first container through a conduit connected to the first container to a second container downstream of the first container, the first container and the conduit defining a continuous free volume above the free surface of the molten material, the free volume extending into a portion of the conduit, wherein the first container is a clarifying container and the second container is a mixing container; A first atmosphere contained in the free volume is discharged to a second atmosphere outside the first container through an exhaust pipe, the exhaust pipe including a proximal end and a distal end opposite to the proximal end, the proximal end being connected to the conduit near the top of the conduit and above the free surface, the exhaust pipe extending downward along a longitudinal axis at an angle α relative to the horizontal plane and providing fluid communication between the first atmosphere and the second atmosphere, and providing a distance between the free surface of the molten material and the bottom of the proximal end of the exhaust pipe for accommodating upward displacement of the glass wire; and The exhaust pipe is heated while the molten material flows, and this heating removes condensate accumulated on the inner surface of the exhaust pipe. The first portion of the conduit extends horizontally from the first container, and the vent pipe is connected to the first portion of the conduit. Wherein, at least one second portion of the catheter extends downward and inclined from the first portion of the catheter at an angle β relative to the horizontal plane.

18. The method of claim 17, further comprising: The molten material is allowed to flow into a forming body, which shapes the molten material into the glass article.

19. The method of claim 18, wherein the glass article is a glass strip.

20. The method of claim 17, wherein the heating comprises: An electric current is established in the heating element.

21. The method of claim 20, wherein the heating element comprises the wall of the exhaust pipe.

22. The method of claim 17, wherein the heating comprises: Current is established between a first electrical flange connected to the exhaust pipe and a second electrical flange connected to at least one of the first container or the conduit.

23. The method of claim 17, further comprising: The molten material is allowed to flow into the forming body, and the molten material is formed into a glass ribbon.

24. The method of claim 23, wherein the forming comprises: The molten material is pulled downward from the forming body.

25. The method of claim 17, further comprising: The covering gas flows into the free volume through the gas delivery pipe.

26. The method of claim 25, wherein the gas delivery pipe is connected to the first container.

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