Glass manufacturing apparatus with delivery conduit system having low impedance drain assembly - Patents.com

Abstract

A delivery conduit system for a glass manufacturing apparatus, the delivery conduit system including a drain assembly configured to allow molten glass to drain from the delivery conduit system, the drain assembly including heating and cooling means capable of selectively altering the fluid impedance presented to the molten glass by the drain assembly to open drain flow of molten glass from components of the delivery conduit system and block flow to a forming body.

Description

[Technical field]

[0001] (Related Applications) This application claims the benefit of priority under 35 U.S.C. Section 119 of U.S. Provisional Application No. 63 / 282,478, filed November 23, 2021, the entire disclosure of which is incorporated herein by reference.

[0002] (Technical field) FIELD OF THE DISCLOSURE This disclosure relates to glass making apparatus, and in particular to glass making apparatus that includes a drain that can stop the flow of molten material to a forming apparatus during ejection. [Background technology]

[0003] The glass making process can be divided into three stages: melting, conditioning, and forming. Precursor materials are heated to form a molten material, bubble forming gases are removed from the molten material, and the molten material is homogenized, for example by stirring. The molten material is then fed to a forming apparatus that forms the molten material into a useful product. Typically after conditioning and before the forming apparatus, drains in the glass making apparatus may be used to drain the molten material from the system if there is a problem with the forming apparatus or the forming process, if there is a problem with the molten material itself, or to change the composition of the molten material in the system.

[0004] However, the drain itself cannot redirect all of the flow of molten material from the system, especially from the molding device. As molten material empties from the system, it may flow to both the molding device and the drain. This can be problematic because the molding system may be damaged by unintended flow of molten material through the molding device during the evacuation process. Summary of the Invention [Means for solving the problem]

[0005] In a first aspect, a glass manufacturing apparatus is disclosed that includes a delivery conduit system configured to convey a flow of molten glass from a delivery vessel to a forming body, the delivery conduit system including an outlet conduit extending from the delivery vessel, an inlet conduit extending from the forming body, a drain assembly coupled between the outlet conduit and the inlet conduit, the drain assembly including a downwardly extending drain tube having an inlet end and an outlet end, a first cooling device positioned adjacent to the delivery conduit system between the drain tube and the forming body, and a heating device configured to heat the outlet end of the drain tube.

[0006] In a second aspect, the heating device of the first aspect may include a pair of electrical flanges attached to the drain pipe.

[0007] In a third aspect, the drain assembly of the first or second aspect can include a first curved conduit section configured to direct the flow of molten glass from a first direction to a second direction different from the first direction.

[0008] In a fourth aspect, the first curved conduit section of any of the first to third aspects can include a first curved conduit portion and a second curved conduit portion, each of the first curved conduit portion and the second curved conduit portion configured to direct the flow of molten glass through a 90 degree turn.

[0009] In a fifth aspect, the first curved conduit section of the fourth aspect comprises a first straight conduit portion coupled between the first curved conduit portion and the second curved conduit portion.

[0010] In a sixth embodiment, the drain tube of the fifth embodiment may be coupled to a first straight conduit section.

[0011] In a seventh aspect, the glass manufacturing apparatus of the fifth aspect can further comprise a second curved conduit section coupled to the first curved conduit section.

[0012] In an eighth aspect, the glass manufacturing apparatus of the seventh aspect can include a second straight conduit portion coupled between the second curved conduit portion and the second curved conduit section.

[0013] In a ninth aspect, the cooling device of the eighth aspect can be located proximate to the second straight conduit section.

[0014] In a tenth aspect, the delivery conduit system of any of the first to ninth aspects may comprise platinum.

[0015] In an eleventh aspect, the inner diameter of the outlet conduit of the third aspect may be smaller than the inner diameter of the first curved conduit section.

[0016] In a twelfth aspect, a first transition pipe can be coupled between the outlet conduit of the eleventh aspect and the first curved conduit section, and an inner diameter of the first transition pipe can vary between an inner diameter of the outlet conduit and an inner diameter of the first curved conduit section.

[0017] In a thirteenth aspect, the inner diameter of the inlet conduit of the third aspect may be smaller than the inner diameter of the first curved conduit section.

[0018] In a fourteenth aspect, a first transition pipe can be coupled between the inlet conduit of the eleventh aspect and the first curved conduit section, and an inner diameter of the first transition pipe can vary between an inner diameter of the inlet conduit and an inner diameter of the first curved conduit section.

[0019] In a fifteenth aspect, the second curved conduit section of the seventh aspect may be coupled to an inlet conduit, and an inner diameter of the inlet conduit may be smaller than an inner diameter of the second curved conduit section.

[0020] In a sixteenth aspect, a second transition pipe can be coupled between the inlet conduit of the eleventh aspect and the second curved conduit section, and the inner diameter of the second transition pipe can vary between the inner diameter of the inlet conduit and the inner diameter of the second curved conduit section.

[0021] In a seventeenth aspect, the glass manufacturing apparatus of any of the first to sixteenth aspects can further include a second cooling device disposed proximate to the outlet conduit.

[0022] In an eighteenth aspect, a glass manufacturing apparatus is described that includes a delivery vessel, a forming body, and a delivery conduit system configured to convey a flow of molten glass from the delivery vessel toward the forming body, the delivery conduit system including: an outlet conduit extending downwardly from the delivery vessel; an inlet conduit extending from the forming body; a drain assembly coupled between the outlet conduit and the inlet conduit, the drain assembly including a first curved conduit section and a second curved conduit section disposed downstream of the first curved conduit section relative to a flow direction of the molten glass; a drain tube extending downwardly from the drain assembly, the drain tube including a proximal end attached to the drain assembly and a distal end opposite the proximal end; a first cooling device disposed downstream from the first curved conduit section and configured to cool at least a portion of the delivery conduit system downstream from the first curved conduit section; and a heating device configured to heat the distal end of the drain tube.

[0023] In a nineteenth aspect, an inner diameter of the outlet conduit can be smaller than an inner diameter of the first curved conduit section.

[0024] In a twentieth aspect, an inner diameter of the inlet conduit can be smaller than an inner diameter of the second curved conduit section.

[0025] In a twenty-first aspect, the first curved conduit section of any of the eighteenth to twenty aspects can be configured to redirect the flow of molten glass from a first direction to a second direction opposite the first direction.

[0026] In a twenty-second aspect, the second curved conduit section of the twenty-first aspect can be configured to direct the flow of molten glass from the second direction to a third direction intermediate the first direction and the second direction.

[0027] In a twenty-third aspect, the third direction can be orthogonal to the first direction.

[0028] In a twenty-fourth aspect, the first curved conduit section of the twenty-first aspect may comprise a first curved conduit portion and a second curved conduit portion, each of the first curved conduit portion and the second curved conduit portion spanning an angle of 90 degrees.

[0029] In a 25th aspect, the first curved conduit section of any of the 18th to 24th aspects may comprise a first curved conduit portion, a second curved conduit portion, and a first straight conduit portion disposed between the first curved conduit portion and the second curved conduit portion.

[0030] In a twenty-sixth aspect, a proximal end of the drain pipe can be attached to the straight section and can be in fluid communication with the straight section.

[0031] In a twenty-seventh aspect, the glass manufacturing apparatus of any of the eighteenth to twenty-sixth aspects can further include a second cooling device disposed proximate to the outlet conduit and configured to cool the outlet conduit.

[0032] In a twenty-eighth aspect, the glass manufacturing apparatus of any of the eighteenth to twenty-seventh aspects may further comprise a second straight conduit portion coupled between the first curved conduit section and the second curved conduit section.

[0033] In a twenty-ninth aspect, a method of draining a delivery conduit system is disclosed, the method including the steps of flowing molten glass from a delivery vessel to a forming body through the delivery conduit system, the delivery conduit system including an outlet conduit connected to the delivery vessel, an inlet conduit connected to the forming body, and a drain assembly connected between the outlet conduit and the inlet conduit, the drain assembly including a drain tube connected to the drain assembly, the drain tube including a proximal end attached to the drain assembly and a distal end opposite the proximal end, the drain tube including a first material plug disposed therein that blocks flow of molten glass from the distal end; heating the distal end of the drain tube to remove the material plug and allow molten glass to flow from the distal end; and cooling the molten glass in a portion of the delivery conduit system downstream from the drain tube to form a second material plug in the delivery conduit system and reduce the flow of molten glass to the forming body.

[0034] A thirtieth aspect can further include cooling at least a portion of the molten glass in the outlet conduit with a second cooling device.

[0035] Both the foregoing general description and the following detailed description illustrate embodiments that are 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 a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the present disclosure and, together with the description, explain the principles and operation thereof. [Brief description of the drawings]

[0036] [Figure 1] 1 is a schematic diagram of an exemplary glass manufacturing apparatus. [Diagram 2] FIG. 2 is a cross-sectional view of a portion of the glass manufacturing apparatus of FIG. 1 including a delivery conduit system having a drain assembly configured to drain molten glass from the forming apparatus and adjacent components, the drain assembly using a radiant heater to heat the molten glass therein. [Diagram 3]FIG. 2 is a cross-sectional view of a portion of the glass manufacturing apparatus of FIG. 1 with an alternative delivery conduit system having a drain assembly configured to drain molten glass from the forming apparatus and adjacent components, the delivery conduit system using electric flanges and direct heating to heat the molten glass therein. [Figure 4] FIG. 2 is a cross-sectional view of a portion of the glass manufacturing apparatus of FIG. 1 with yet another exemplary delivery conduit system having a drain assembly configured to drain molten glass from the forming apparatus and adjacent components, the drain assembly using a radiant heater to heat the molten glass therein. [Diagram 5] 5 is a cross-sectional view of the drain assembly of FIG. 4 showing various degrees of freedom (eg, rotation and length) for assembly of the drain assembly. [Figure 6] FIG. 2 is a cross-sectional view of a portion of the glass manufacturing apparatus of FIG. 1 with yet another exemplary delivery conduit system having a drain assembly configured to drain molten glass from the forming apparatus and adjacent components, the drain assembly using electric flanges and direct heating to heat the molten glass therein. [Figure 7] 7 is a cross-sectional view of a portion of the glass manufacturing apparatus of FIG. 1 including the delivery conduit system of FIG. 6 and showing refractory insulation disposed about the delivery conduit system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like elements. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0038] As used herein, the term "about" means that 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, as desired, to reflect tolerances, conversion factors, rounding, measurement errors, and the like, as well as other factors known to those of ordinary skill in the art.

[0039] 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 as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will further be understood that the endpoints of each of the ranges are significant in relation to the other endpoint, and independently of the other endpoint.

[0040] Directional terms used herein, e.g., upper, lower, right, left, front, rear, above, below, are given only with reference to the illustrated figures and are not intended to imply absolute directions.

[0041] Unless otherwise indicated, the methods described herein are not intended to be construed as requiring that its steps be performed in a particular order, or that it require a particular orientation of any apparatus. Thus, where a method claim does not actually recite an order in which its steps are to be followed, or where any apparatus claim does not actually recite an order or orientation for individual components, or where the steps are not specifically recited in the claim or specification otherwise to be limited to a particular order, or where no particular order or orientation for the components of the apparatus is recited, no order or orientation is intended to be inferred in any respect. This is true for all possible non-expressive bases for interpretation, including logical considerations regarding the arrangement of steps, operational flow, order of components, or orientation of components, general meaning derived from grammatical construction or punctuation, and the number or type of embodiments described in the specification.

[0042] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to an "a" component includes aspects having two or more such components unless the context clearly dictates otherwise.

[0043] The terms "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 "example" should not be construed as preferred or advantageous over other aspects or designs. Moreover, the examples are provided only for purposes of clarity and understanding and are not intended to limit or restrict in any way the disclosed subject matter or relevant portions of this disclosure. It should be understood that numerous additional or alternative examples of varying scope may be presented, but have been omitted for purposes of brevity.

[0044] As used herein, the terms "comprising" and "including," and variations thereof, unless otherwise indicated, are intended to be synonymous and open ended. A list of elements following the transitional phrase "comprising" or "including" is a non-exclusive list, such that there may be elements in addition to the elements specifically stated in the list.

[0045] As used herein, the terms "substantial," "substantially," and variations thereof are intended to note that a described feature is equal or nearly equal to a value or description. For example, a "substantially planar" surface is intended to indicate a surface that is planar or nearly planar. Furthermore, "substantially" is intended to indicate that two values ​​are equal or nearly equal. In some embodiments, "substantially" can refer to values ​​that are within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

[0046] An exemplary glass manufacturing apparatus 10 is shown in FIG. 1. The glass manufacturing apparatus 10 comprises a glass melting furnace 12 including a melting vessel 14. In addition to the melting vessel 14, the glass melting furnace 12 can optionally include one or more additional components, such as heating elements (e.g., combustion burners and / or electrodes) configured to heat the raw materials and convert the raw materials into molten material that, when cooled, can form a glass article. For example, the melting vessel 14 can be an electrically boosted melting vessel, where energy is added to the raw materials by both combustion burners and direct heating, where an electric current is passed through the raw materials and energy is added to the raw materials by Joule heating. Hereinafter, the molten material is referred to as molten glass. The glass article can be, for example, a silicate glass article, including borosilicate glass, aluminoborosilicate glass, alkali-free aluminoborosilicate glass, or soda-lime glass.

[0047] The glass melting furnace 12 may include other thermal management devices (e.g., thermal insulation components) that reduce heat loss from the melting vessel. The glass melting furnace 12 may include mechanical, electronic, and / or electromechanical devices that facilitate melting of the raw materials into a glass melt. The glass melting furnace 12 may include a support structure (e.g., a support chassis, support members, etc.) or other components.

[0048] The melting vessel 14 can be formed from a refractory material, such as a refractory ceramic material including alumina or zirconia, but the refractory ceramic material can include other refractory materials, such as yttrium (e.g., yttria, yttria stabilized zirconia, yttrium phosphate), zircon (ZrSiO4), or alumina-zirconia-silica, or chromium oxide, alternatively or in any combination. In some embodiments, the melting vessel 14 can be constructed of refractory ceramic bricks.

[0049] As used herein, a refractory material is a non-metallic inorganic material that is polycrystalline, multiphasic, inorganic, porous, heterogeneous, and suitable as a component of an apparatus or system exposed to temperatures above 538° C. For example, the refractory material can include, but is not limited to, oxides of aluminum, silicon, magnesium, calcium, yttrium, and zirconium, alone or in combination. The refractory material can include a binder material.

[0050] The glass melting furnace 12 can be incorporated as a component of a glass manufacturing apparatus configured to produce glass articles, such as glass ribbons, but the glass manufacturing apparatus can be configured to form other glass articles, such as, but not limited to, glass rods, glass tubes, glass envelopes (e.g., glass envelopes for lighting devices, such as light bulbs), and glass lenses. In some examples, the glass melting furnace 12 can be included in a glass manufacturing apparatus that consists of a slot draw apparatus, a float bath apparatus, a downdraw apparatus (e.g., a fusion downdraw apparatus), an updraw apparatus, a press apparatus, a rolling apparatus, a tube draw apparatus, or any other glass manufacturing apparatus that would benefit from the present disclosure. By way of example, FIG. 1 shows a schematic of the glass melting furnace 12 as a component of a slot draw glass manufacturing apparatus 10. The slot draw process operates by feeding molten glass into a forming body with a slot at the bottom. The molten glass flows from the slot and can be drawn downward therefrom by gravity and counter-rotating drawing rolls located below the slot. The glass ribbon thus formed can then be processed into individual glass sheets or wound onto a spool as a glass ribbon.

[0051] Glass manufacturing system 10 may optionally include upstream glass manufacturing equipment 16 disposed upstream of melting vessel 14. In some embodiments, some or all of upstream glass manufacturing equipment 16 may be incorporated as part of glassmelting furnace 12.

[0052] As shown in FIG. 1 , the 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 the raw material delivery device 20. The raw material storage bin 18 can be configured to store raw material 24 that can be fed to the melting vessel 14 of the glass melting furnace 12 through one or more feed openings, as indicated by arrow 26. The raw material 24 typically includes one or more glass-forming metal oxides and one or more modifiers. In some embodiments, the raw material delivery device 20 can be powered by the motor 22 to deliver a predetermined amount of raw material 24 from the raw material storage bin 18 to the melting vessel 14. In further embodiments, the motor 22 can power the raw material delivery device 20 to introduce the raw material 24 at a controlled rate based on a level of molten glass sensed downstream of the melting vessel 14 relative to the flow direction of the molten glass. The raw material 24 in the melting vessel 14 can then be heated to form molten glass 28. Typically, the raw material is added to the melting vessel as particulates, such as various "sands." The feedstock 24 may also include waste glass (i.e., cullet) from previous melting and / or forming operations. A combustion burner may be used to initiate the melting process. In an electrically boosted melting process, once the electrical resistance of the feedstock has been sufficiently lowered by the combustion burner, an electrically boost may be initiated by generating an electrical potential between electrodes placed in contact with the feedstock, thereby establishing an electrical current through the feedstock, and the feedstock typically enters or is in a molten state.

[0053] The glass manufacturing system 10 may also include downstream glass manufacturing equipment 30 disposed downstream of the glassmelting furnace 12 relative to the flow direction of the molten glass 28. In some embodiments, a portion of the downstream glass manufacturing equipment 30 may be incorporated as part of the glassmelting furnace 12. For example, a first connecting conduit 32, described below, or other portions of the downstream glass manufacturing equipment 30 may be incorporated as part of the glassmelting furnace 12.

[0054] The downstream glass making apparatus 30 may include a first conditioning chamber, such as a fining vessel 34, disposed downstream of the melting vessel 14 and connected to the melting vessel 14 by a first connecting conduit 32 as described above. The molten glass 28 may be gravity fed from the melting vessel 14 to the fining vessel 34 by the first connecting conduit 32. The first connecting conduit 32 thus provides a flow path for the molten glass 28 from the melting vessel 14 to the fining vessel 34. However, other conditioning chambers may be disposed downstream of the melting vessel 14, for example, between the melting vessel 14 and the fining vessel 34. In some embodiments, a conditioning chamber may be used between the melting vessel and the fining chamber. For example, the molten glass from the first melting vessel may be further heated in a second melting (conditioning) vessel or cooled in the second melting vessel to a temperature lower than the temperature of the molten glass in the first melting vessel before entering the fining chamber.

[0055] The gas bubbles can be removed from the molten glass 28 by a variety of techniques. For example, the raw material 24 can include a polyvalent compound (i.e., a fining agent), such as tin oxide, that undergoes a chemical reduction reaction when heated to release oxygen. Other suitable fining agents can include, but are not limited to, arsenic, antimony, iron, and / or cerium, although the use of arsenic and antimony may be discouraged for environmental reasons in some applications due to their toxicity. The fining vessel 34 is heated, for example, to a temperature higher than the internal temperature of the melting vessel, whereby the fining agent is heated to a reaction temperature sufficient to induce chemical reduction of the fining agent(s). Oxygen produced by the chemical reduction of the fining agent(s) contained in the molten glass diffuses into the gas bubbles generated during the melting process. The enlarged and increasingly buoyant gas bubbles rise to the free surface of the molten glass in the fining vessel and are then released from the fining vessel, for example, through a vent tube in fluid communication with the atmosphere above the free surface.

[0056] The downstream glass production apparatus 30 may further include a mixing device 36, e.g., another conditioning chamber such as a stirred vessel, for mixing the molten glass flowing downstream from the fining vessel 34. The mixing device 36 may be used to provide a homogenous glass melt composition, thereby reducing chemical and / or thermal non-uniformities that may otherwise be present in the molten glass exiting the fining vessel. As shown, the fining vessel 34 may be connected to the mixing device 36 by a second connecting conduit 38. Thus, the molten glass 28 may be gravity fed from the fining vessel 34 to the mixing device 36 by the second connecting conduit 38. Typically, the molten glass in the mixing device 36 includes a free surface, with a free (e.g., gas) volume extending between the free surface and the top of the mixing device. Although the mixing device 36 is shown downstream of the fining vessel 34 with respect to the flow direction of the molten glass 28, in other embodiments, the mixing device 36 may be located upstream of the fining vessel 34. In some embodiments, the downstream glass manufacturing equipment 30 can include multiple mixing devices, such as a mixing device upstream of the fining vessel 34 and a mixing device downstream of the fining vessel 34. If used, the multiple mixing devices can be of the same design or of different designs. One or more of the vessels and / or conduits can include stationary mixing blades to further promote mixing and subsequent homogenization of the molten material disposed therein.

[0057] The downstream glass manufacturing apparatus 30 may further include another conditioning chamber, such as a delivery vessel 40 located downstream of the mixing device 36. The delivery vessel 40 may function as an accumulator and / or flow controller to provide a steady flow of molten glass 28 to the forming body 42 through an outlet conduit 44. In some embodiments, the molten glass in the delivery vessel 40 may include a free surface, and a free volume may extend upward from the free surface to the top of the delivery vessel. As shown, the mixing device 36 may be connected to the delivery vessel 40 by a third connecting conduit 46, and the molten glass 28 may be gravity fed from the mixing device 36 to the delivery vessel 40 by the third connecting conduit 46.

[0058] The downstream glass manufacturing apparatus 30 may further include a forming apparatus 48 configured to form a glass article, e.g., a glass ribbon. Thus, the forming apparatus 48 may comprise a forming body 42, e.g., a forming vessel, with an outlet conduit 44 arranged to deliver the molten glass 28 from the delivery vessel 40 to an inlet conduit 50 of the forming vessel. The forming vessel may comprise a slot at its bottom through which the molten glass delivered to the open volume of the forming vessel 42 flows and produces a ribbon of molten glass 60 that is drawn from the bottom edge in a drawing direction 56 by applying a downward tension to the glass ribbon by gravity and / or counter-rotating drawing rolls. Alternatively, the forming body 42 may comprise, e.g., a fusion downdraw glass manufacturing apparatus, with the molten glass passing through the delivery vessel 40 and exiting the outlet conduit 44 and the inlet conduit 50 into a trough within the forming body 42. The molten glass overflows the walls of the trough and travels down along a converging forming surface as separate streams of molten glass. The separate streams of molten glass join along the bottom edge below the former to produce a ribbon of molten glass 60, which is drawn from the bottom edge in a draw direction 56, again by gravity and / or by counter-rotating drawing rolls applying downward tension to the glass ribbon. In either case, the glass ribbon 60 undergoes a viscous transition from a viscous state to a viscoelastic state to an elastic state, acquiring mechanical properties that give the glass ribbon 60 stable dimensional properties. The glass ribbon 60 can be separated into short lengths, such as glass sheets 62, by a glass separator 64. Alternatively, the glass ribbon can be wound onto a reel.

[0059] The components of the downstream glass making equipment 30, including any one or more of the connecting conduits 32, 38, 46, the fining vessel 34, the mixing device 36, the delivery vessel 40, the outlet conduit 44, or the inlet conduit 50, may be formed from high temperature metals. Suitable metals include platinum group metals selected from the group consisting of platinum, iridium, rhodium, osmium, ruthenium, and palladium, or alloys thereof. For example, the downstream components of the glass making equipment may be formed from a platinum-rhodium alloy including about 70% to about 90% platinum and about 10% to about 30% rhodium by weight.

[0060] 2 is a cross-sectional view of a portion of downstream glass manufacturing apparatus 30, namely, delivery conduit system 90 including outlet conduit 44, inlet conduit 50, and drain assembly 100, configured to deliver molten glass from delivery vessel 40 to forming body 42. Outlet conduit 44 extends from delivery vessel 40 and provides a path for the molten glass to exit delivery vessel 40. Inlet conduit 50 connects to forming body 42 and provides a path for molten glass 28 to enter forming body 42. The drain assembly 100 couples the distal end 102 of the outlet conduit 44 to the distal end 104 of the inlet conduit 50 and provides a first flow path 106 for the molten glass 28 traversing from the outlet conduit 44 to the inlet conduit 50 and the forming body 42, and a second flow path 108 different from the first flow path 106 that enables the molten glass to be discharged from any one or more of the delivery vessel 40, the outlet conduit 44, the inlet conduit 50, the drain assembly 100, or the forming body 42.

[0061] The drain assembly 100 includes a curved conduit section 110 configured to direct the flow of molten glass 28 from a first downward flow direction 112 to a second flow direction 114 that is different from the first flow direction 112. For example, the second flow direction 114 can be perpendicular to the first flow direction 112. The drain assembly 100 can further include a first transition tube 115 that couples the distal end 102 of the outlet conduit 44 to a first end 116 of the curved conduit section 110. The drain assembly 100 can further include a second transition tube 118 that couples the second end 120 of the curved conduit section 110 to a distal end 104 of the inlet conduit 50. For example, an inner diameter (ID) 130 of the first end 116 of the curved conduit section 110 can be larger than an inner diameter ID 132 of the distal end 102 of the outlet conduit 44. Similarly, the second end 120 of the curved conduit section 110 can have an inner diameter ID larger than the inner diameter ID of the distal end 104 of the inlet conduit 50. Thus, the inner diameters ID of the first and second transition pipes 115, 118 can vary along the length of the respective transition pipes to facilitate coupling of attached conduits, e.g., the outlet conduit 44 and the inlet conduit 50, to the curved conduit section 110 when these conduits have different inner diameters than the inner diameter of the curved conduit section 110 to which they are coupled. The inner diameter of the curved conduit section 110 can be uniform from the first end 116 to the second end 120. The inner diameter ID of the curved conduit section 110 can be larger than one or both of the inner diameters ID of the outlet conduit 44 and the inlet conduit 50.

[0062] The drain assembly 100 further comprises a drain tube 140 extending between its proximal (inlet) end 142 and distal (outlet) end 144, the proximal end 142 being located in and connected to the curved conduit section 110 such that an inner passageway 146 of the drain tube 140 is in fluid communication with an inner passageway 148 of the curved conduit section 110. For example, the proximal end 142 may be connected to the lowest point of the curved conduit section 110, thereby facilitating efficient drainage of the connected conduit. The drain tube 140 extends in a downward direction, e.g., vertically, from the curved conduit section 110, although inclined orientations ranging from greater than 0 degrees to 45 degrees relative to vertical are also contemplated, e.g., from greater than 0 degrees to about 5 degrees from vertical, from greater than 0 degrees to about 10 degrees from vertical, from greater than 0 degrees to about 15 degrees from vertical, from greater than 0 degrees to about 20 degrees from vertical, from greater than 0 degrees to about 25 degrees from vertical, from greater than 0 degrees to about 30 degrees from vertical, from greater than 0 degrees to about 35 degrees from vertical, from greater than 0 degrees to about 40 degrees from vertical (including all ranges and subranges therebetween). Although illustrated as a straight tube, the drain tube 140 may include one or more curved sections, or a combination of straight and curved sections. The drain tube 140 should be as short as possible to avoid unnecessary impedance to the fluid flow as the drain tube is operational and the molten glass is drained therefrom.

[0063] The drain assembly 100 further comprises a first cooling device 150a disposed downstream of the curved conduit section 110. For example, the first cooling device 150a can be disposed adjacent to the inlet conduit 50. The first cooling device 150a can comprise, for example, a helical tube surrounding the inlet conduit 50 downstream of the curved conduit section 110 relative to the flow direction of the molten glass. The first cooling device 150a can be configured such that a coolant can flow through it, thereby cooling an adjacent portion of the inlet conduit 50. For example, the helical tube can include a hollow interior that provides a flow path for the coolant to pass through. A suitable coolant can be one or more non-oxidizing gases, such as nitrogen, any one or more of Group VIIIA gases (e.g., helium, neon, argon, krypton, xenon), or a combination thereof. However, the first cooling device 150a may utilize other forms of cooling capable of cooling a portion of the inlet conduit 50 around the circumference of the inlet conduit 50 instead of or in addition to cooling tubes configured to carry a coolant therethrough. For example, the first cooling device 150a may comprise a cooling jacket rather than a cooling tube, or a thermoelectric cooling device.

[0064] As shown in FIG. 2, one or more heating elements 160 may be disposed adjacent the outlet conduit 44, the drain assembly 100, and / or the inlet conduit 50. The heating elements 160 may be resistive heating elements that generate heat by Joule heating and heat associated metal components by radiative and / or conductive heating. The heating elements 160 may include a helical coil wound around the respective conduit, although other physical forms of heating elements may be used, such as multiple individual heating elements disposed around the respective conduit. In some cases, the distal end 144 of the drain pipe 140 may be heated by a similar heating element 160. However, as shown in FIG. 2, in some cases, the distal end 144 may be heated by a flame provided by a burner 162, for example a fuel-air burner.

[0065] An optional second cooling device 150b can be disposed proximate the exit conduit 44. For example, the second cooling device 150b can be a cooling coil configured to receive a flow of cooling fluid through an interior passage thereof. The second cooling device 150b can be used, for example, to reduce or stop flow from the exit conduit 44 to the former 42 until such time that heating of the distal end 144 can be terminated.

[0066] The drain assembly 100, including the drain tube 140, may be formed from a precious metal, such as a precious metal compatible with the precious metal forming the outlet conduit 44 and / or the inlet conduit 50. 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, the drain assembly 100 may be formed from a platinum-rhodium alloy including about 70% to about 90% platinum and about 10% to about 30% rhodium by weight.

[0067] Alternatively, or in addition to heating element 160, electrical flanges 170 may be attached to portions of downstream glass making equipment 30 for heating purposes. For example, although FIGURE 1 shows electrical flanges 170 attached to outlet conduit 44, finer vessel 34, and inlet conduit 50, electrical flanges 170 may be attached to other metal components of downstream glass making equipment 30. Electrical flanges 170 are electrically connected to one or more power sources (not shown) such that an electrical current can be established in the section of the metal component to which the electrical flanges are attached, such as between adjacent successive electrical flanges.

[0068] 3 thus illustrates a delivery conduit system 92 similar to delivery conduit system 90, except that electrical flanges 170 may take the place of one or more heating elements 160. More specifically, electrical flanges 170a and 170b are shown attached to outlet conduit 44, electrical flanges 170c and 170d are shown attached to inlet conduit 50, and electrical flanges 170e, 170f, 170g, and 170h are shown attached to drain pipe 140. The number and location of electrical flanges 170 may be defined as needed. For example, although two electrical flanges are shown attached to outlet conduit 44, less than two electrical flanges (e.g., one electrical flange), or more than two electrical flanges (e.g., three electrical flanges, four electrical flanges, or five or more electrical flanges) may be attached to outlet conduit 44. An electrical current is established in the walls of the metal components between adjacent successive electrical flanges by one or more electrical sources. Thus, for example, a first current can be established between electrical flange 170a and electrical flange 170b. A second current can be established between electrical flange 170b and electrical flange 170c. A third current can be established between electrical flange 170c and electrical flange 170d. A fourth current can be established between electrical flange 170b and electrical flange 170e. A fifth current can be established between electrical flange 170e and 170f. A sixth current can be established between electrical flange 170f and 170g. The various currents heat respective portions of the metal components between adjacent successive electrical flanges by Joule heating (e.g., outlet conduit 44, inlet conduit 50, compact 42, and drain assembly 100). The physical arrangement of the electrical flanges and the flow of current therebetween can be configured according to the needs of a particular system. Thus, the above physical arrangements and currents are exemplary and are provided as non-limiting examples of possible configurations. The electrical flange 170 may comprise a precious metal, such as a precious metal that is compatible with the precious metal forming the outlet conduit 44 and / or the inlet conduit 50. 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, the electrical flange 170 can include a platinum-rhodium alloy including about 70% to about 90% platinum and about 10% to about 30% rhodium by weight. A portion of the electrical flange 170 can include nickel. For example, an outer portion of the flange that is not exposed to high temperatures can include nickel or a nickel alloy.

[0069] As described above with respect to the delivery conduit system 90, the delivery conduit system 92 can include first and second cooling devices 150a and 150b. For example, the first and second cooling devices 150a, 150b can include cooling coils configured to receive a flow of a cooling fluid through an internal passageway thereof.

[0070] The various currents mentioned above (e.g., first through sixth currents) need not have the same magnitude. Thus, different portions of the metal components (e.g., outlet conduit 44, inlet conduit 50, molding 42, and drain assembly 100) can be heated to different temperatures by controlling the individual currents between pairs of electrical flanges as needed. Electrical flanges 170f and 170g can be closely spaced to selectively heat a short length of drain pipe 140 near its distal end 144.

[0071] 4 illustrates another delivery conduit system 94 similar to the delivery conduit system 90, but with a drain assembly 200 including a first curved conduit section 202 and a second curved conduit section 204 disposed downstream of the first curved conduit section 202 relative to the flow of molten glass. The first curved conduit section 202 may be a U-shaped conduit section defining an interior passage 206 for the flow of molten glass 28 along a first flow path 208. Thus, the downward first flow direction 112 of the molten glass 28 from the outlet conduit 44 may be redirected by the first curved conduit section 202 into an upward second flow direction 114 of the molten glass in a flow direction 210 (at the exit of the first curved conduit section 202). For example, the first curved conduit section 202 may extend in a 180 degree curve such that the flow direction 210 is opposite the first flow direction 112, although other curvatures are contemplated and may be provided as needed. The second curved conduit section 204 is coupled to the first curved conduit section 202. The flow of molten glass exiting the first curved conduit section 202 is further directed by the second curved conduit section 204 into a transverse flow of the molten glass along the second flow direction 114. The second flow direction 114 may be orthogonal to the first flow direction 112 and / or the flow direction 210 in the inlet conduit 50. For example, either the first curved conduit section 202 or the second curved conduit section 204, or both, may include a 90 degree bend conduit. The second curved conduit section 204 is coupled to the distal end 104 of the inlet conduit 50, from which the flow of molten glass is delivered to the forming body 42.

[0072] The drain assembly 200 further includes a drain tube 214 extending downwardly between a proximal end 216 and a distal end 218, the proximal end 216 being connected to the first curved conduit section 202 such that an internal passage 220 of the drain tube 214 is in fluid communication with the internal passage 206 of the first curved conduit section 202. Although the drain pipe 214 is shown as a vertically extending tube, inclined orientations are also contemplated, such as from greater than 0 degrees to 45 degrees from vertical, e.g., from greater than 0 degrees to 45 degrees from vertical, e.g., from greater than 0 degrees to about 5 degrees from vertical, from greater than 0 degrees to about 10 degrees from vertical, from greater than 0 degrees to about 15 degrees from vertical, from greater than 0 degrees to about 20 degrees from vertical, from greater than 0 degrees to about 25 degrees from vertical, from greater than 0 degrees to about 30 degrees from vertical, from greater than 0 degrees to about 35 degrees from vertical, from greater than 0 degrees to about 40 degrees from vertical (including all ranges and subranges therebetween). Although shown as a straight pipe, the drain pipe 214 need not be straight and may include one or more curved sections. The drain tube 214 defines a second flow path 224 along which molten glass may be discharged from any one or more of the delivery vessel 40, the outlet conduit 44, the drain assembly 200, the forming body 42, and / or the inlet conduit 50.

[0073] The drain assembly 200 may further comprise a first transition tube 230 coupling the distal end 102 of the outlet conduit 44 to a first end 232 of the first curved conduit section 202. The drain assembly 200 may further comprise a second transition tube 234 coupling the second end 236 of the first curved conduit section 202 to the distal end 104 of the inlet conduit 50. For example, as shown in FIG. 4, an inner diameter (ID) 240 of the first end 232 of the first curved conduit section 202 may be larger than the inner diameter ID 132 of the distal end 102 of the outlet conduit 44. Similarly, the second end 236 of the second curved conduit section 204 may have an inner diameter ID larger than the inner diameter ID of the distal end 104 of the inlet conduit 50. Thus, the inner diameter ID of the first and second transition pipes 230 and 234 may vary along the length of the respective transition pipes to facilitate coupling of attached conduits, e.g., the outlet conduit 44 and the inlet conduit 50, to the first curved conduit section 202 or the second curved conduit section 204, respectively, when the conduits have inner diameters different from the inner diameters of the first curved conduit section 202 or the second curved conduit section 204. The inner diameter of the first curved conduit section 202 may be uniform along the length of the first curved conduit section. Similarly, the inner diameter of the second curved conduit section 204 may be uniform along the length of the second curved conduit section. The inner diameter ID of the first curved conduit section 202 and / or the second curved conduit section 204 may be larger than one or both of the inner diameter ID of the outlet conduit 44 and the inner diameter ID of the inlet conduit 50.

[0074] The delivery conduit system 94 comprises a first cooling device 150a disposed downstream of the first curved conduit section 202 with respect to the flow direction of the molten glass. As described in the above embodiment, the first cooling device 150a may comprise a helical tube disposed between the first curved conduit section 202 and the second curved conduit section 204, and the first cooling device 150a is configured to allow a coolant to flow through the helical tube, thereby cooling the molten glass conveyed therethrough. For example, the helical tube may include a hollow interior that provides a flow path for the coolant. A suitable coolant may be one or more non-oxidizing gases (e.g., nitrogen, a noble gas, or a combination thereof) or a liquid (water). However, the first cooling device 150a may take other forms capable of cooling a portion of the delivery conduit system 94. For example, the first cooling device 150a may comprise a cooling jacket or a thermoelectric cooling device.

[0075] As shown in FIG. 4 and similar to the embodiment of FIG. 2, one or more heating elements 160 may be positioned proximate the outlet conduit 44, the drain assembly 200, the inlet conduit 50, and / or the drain pipe 214. As described above, the heating elements 160 may be resistive heating elements that generate heat by Joule heating and heat adjacent metal components by radiative and / or conductive heating. In some cases, the distal end 218 of the drain pipe 214 may be heated by a similar heating element 160. In some cases, the distal end 218 may be heated by a flame provided by a burner 162, such as a fuel-air burner.

[0076] As described above with respect to the delivery conduit system 90, the delivery conduit system 94 can optionally include a second cooling device 150b disposed proximate the exit conduit 44, the second cooling device 150b configured to reduce or eliminate flow from the exit conduit 44. For example, when the second cooling device 150b is activated, such as by initiating a flow of coolant therethrough, the viscosity of the molten glass in the exit conduit 44 adjacent the second cooling device 150b can be increased, thereby forming a glass plug in the exit conduit.

[0077] Referring to FIG. 5, the drain assembly 200 can include one or more straight conduit segments. For example, the first curved conduit section 202 can include a first curved conduit segment 250 and a second curved conduit segment 252, and the first straight conduit segment 254 can be coupled between the first curved conduit segment 250 and the second curved conduit segment 252. Similarly, the second straight conduit segment 256 can be coupled between the second curved conduit segment 252 and the second curved conduit section 204. The arrangement of curved and straight lengths of conduit shown in FIG. 5 allows the drain assembly to be configured in a more versatile way than if only curved lengths of conduit were used. For example, as shown in FIG. 5, the length 258 of the first straight conduit segment 254 can be increased or decreased as needed to accommodate a predetermined horizontal separation between the delivery vessel 40 (e.g., the outlet conduit 44) and the forming body 42 (e.g., the inlet conduit 50). Similarly, the length 260 of the second straight conduit section 256 can be increased or decreased as needed to accommodate a given vertical separation between the delivery vessel 40 and the forming body 42 (e.g., the inlet conduit 50). Additionally, the angular orientation between the various curved and straight sections of the drain assembly conduit (indicated by the curved arrow 262 and respective axes in FIG. 5), as well as their lengths, can be arranged as needed to provide multiple degrees of freedom of movement and allow the drain assembly to facilitate multiple mechanical arrangements of the delivery vessel 40 and the forming body 42 relative to one another. In particular, the second straight conduit section 256 can be utilized as a convenient location for locating the first cooling device 150a. For example, the first cooling device 150a can be located proximate to the second straight conduit section 256. 4, for example, where the first cooling device 150a is shown as a helical tube wound around a straight conduit section 256 coupled between the first curved conduit section 202 and the second curved conduit section 204. However, the first cooling device 150a may be located in other portions of the delivery conduit system 92 or adjacent the inlet conduit 50.In the embodiment of FIG. 5, the drain pipe 214 is shown connected to and descending from a first straight conduit portion 254 disposed between a first curved conduit portion 250 and a second curved conduit portion 252.

[0078] The electrical flanges 170 can be attached to a portion of the downstream glass making equipment and can be configured to establish an electrical current in that portion of the downstream glass making equipment. The various electrical flanges shown in Figure 3 are similarly suited to the embodiment shown in Figure 4, including a distributed current arrangement that can heat portions of the metal component between adjacent electrical flanges to the same or different temperatures.

[0079] Thus, FIG. 6 illustrates another delivery conduit system 96 including a drain assembly 200 similar to delivery conduit system 94, except that delivery conduit system 96 includes electrical flanges 170 instead of one or more heating elements 150. For example, FIG. 6 illustrates electrical flanges 170 attached to outlet conduit 44, finer 34, and inlet conduit 50, although electrical flanges 170 may be attached to other metal components of downstream glass manufacturing equipment 30. Electrical flanges 170 are electrically connected to one or more power sources (not shown) such that an electrical current may be established in the sections of the metal components to which the electrical flanges are attached. More specifically, FIG. 6 illustrates electrical flanges 170a and 170b attached to outlet conduit 44, electrical flanges 170c and 170d attached to inlet conduit 50, and electrical flanges 170e, 170f, 170g, and 170h attached to drain pipe 314. The number and location of electrical flanges 170 may be defined as needed. For example, although two electrical flanges are shown attached to the outlet conduit 44, less than two electrical flanges (e.g., one electrical flange), or more than two electrical flanges (e.g., three electrical flanges, four electrical flanges, or five or more electrical flanges) can be attached to the outlet conduit 44. An electrical current is established in the walls of the metal component between adjacent electrical flanges by one or more electrical sources. Thus, for example, a first electrical current can be established between electrical flange 170a and electrical flange 170b. A second electrical current can be established between electrical flange 170b and electrical flange 170c. A third electrical current can be established between electrical flange 170c and electrical flange 170d. A fourth electrical current can be established between electrical flange 170b and electrical flange 170e. A fifth electrical current can be established between electrical flanges 170e and 170f. A sixth electrical current can be established between electrical flanges 170f and 170g. The various electrical currents heat, by Joule heating, respective portions of the metal components between adjacent electrical flanges (eg, outlet conduit 44, inlet conduit 50, former 42, and drain assembly 200).

[0080] The various currents (e.g., first through sixth) need not have the same magnitude. Thus, different portions of the metal component (e.g., outlet conduit 44, inlet conduit 50, compact 42, and drain assembly 200) can be heated to different temperatures by controlling the individual currents between pairs of electrical flanges as needed. Electrical flanges 170f and 170g can be closely spaced to selectively heat a short length of drain tube 314 near the distal end 318 of the drain tube.

[0081] In addition to the curved conduit sections described with respect to delivery conduit system 92, delivery conduit system 96 may include straight conduit portions as shown in FIG.

[0082] In addition to the above aspects, any one of the embodiments described herein can be surrounded by one or more layers of refractory insulation selected to control heat loss from the delivery conduit system. For example, FIG. 7 shows the delivery conduit system shown in FIG. 6 encased within a layer of refractory insulation 300. The refractory insulation can be selected from mullite, insulating firebrick, Johns Manville Duraboard (e.g., Duraboard 3000), or other refractory insulation materials with various thermal conductivities. The thermal conductivity of the refractory insulation can be selected as needed to control a portion of the delivery conduit system to a predetermined temperature depending on the desired viscosity of the molten glass therein. In addition, the refractory insulation surrounding the delivery conduit system, particularly the drain assembly, should be configured to allow free movement (e.g., expansion) of the delivery conduit system when the system is heated. The refractory insulation 300 should allow the delivery conduit system to expand radially, horizontally, and vertically when the delivery conduit system moves during thermal expansion. Thus, the fire resistant insulation may be separated from all or a portion of the delivery conduit system, such as the drain assembly, by gap 302. This may omit anchors extending from the delivery conduit system that may connect and support the delivery conduit system within the fire resistant insulation.

[0083] During normal operation, the delivery vessel 40 delivers the molten glass 28 through a delivery conduit system to a forming body 42. The forming body 42 may comprise, for example, a slot-draw apparatus comprising a vessel that receives the molten glass from the delivery conduit system. The molten glass flows out of the vessel through slots disposed in the underside of the vessel, where the molten glass forms a glass ribbon that is drawn downward by drawing rolls and gravity. The delivery conduit system and slots provide a predetermined hydraulic impedance to the flow of the molten glass. In particular, during normal operation, the slots may represent the largest single source of hydraulic impedance and may determine the magnitude of the molten glass flow achievable for a given molten glass viscosity.

[0084] During glass forming operations, it may become necessary to stop the forming process. For example, repair or replacement of a particular piece of glass-making equipment, such as glass-making equipment downstream of the former or the former itself, may be required. In such cases, the drain tube may be opened. Under normal operating conditions, the drain tube is closed by limiting heating of the drain tube and allowing it to reach a temperature below the softening temperature of the molten glass. Depending on the arrangement of the heating device or equipment, this may be done by reducing the power supplied to an external resistance heater adjacent the drain tube, by reducing the current through an electrical flange (and drain tube) located at or near the distal end of the drain tube, or by removing the flame from the burner from the distal end. Any one of these actions may result in solidification of the material in the drain tube, reducing the viscosity of the material in the drain tube sufficiently to form a plug that blocks the drain tube and prevents molten glass from flowing out the distal end (i.e., outlet) of the drain tube.

[0085] When the molten glass is to be discharged from the delivery conduit system, depending on the configuration of the heating device or devices, the drain tube can be opened by increasing the power to the heating element (e.g., a resistive heater) thereby increasing the heat output from the heating element, increasing the magnitude of the current to an electrical flange at the distal end of the drain tube, or applying a flame from a burner, thereby melting the previously formed glass plug and allowing the molten glass to flow through and out of the drain tube. The drain tube thus provides a preferential flow path for the molten glass when the drain tube is opened by lowering the overall impedance of the drain flow path. This can be accomplished, for example, by ensuring that the inner diameter ID of the drain assembly, including the drain tube, is larger than the inner diameter ID of the connected conduits, for example, the outlet conduit of the delivery vessel and / or the inlet conduit of the forming body.

[0086] Such a continued flow of molten glass into the forming body may prevent downstream repairs and / or may result in damage to the forming body, as the molten glass may become blocked by insufficient flow and must be thrashed before the forming process can be resumed. In either case, it may be necessary to completely stop the flow of molten glass into the forming body. Thus, the first cooling device 150a may be actuated, for example, by initiating a flow of coolant through the cooling device (e.g., a cooling tube), thereby solidifying the molten glass in the portion of the delivery conduit system downstream of the drain tube and forming a glass plug therein. The resulting glass plug blocks further flow into the forming body.

[0087] In some cases, it may be necessary to reduce or eliminate flow to the forming body 42 faster than heating of the drain tube 140 can accommodate (increasing the viscosity of the glass plug blocking the drain tube so that molten glass can begin to flow through the drain tube). If an optional second cooling device 150b is included, the second cooling device 150b can be activated to reduce or eliminate the flow of molten glass from the outlet conduit 44. When the drain tube 140 is opened, the second cooling device 150b can be deactivated if necessary, for example to drain the delivery vessel 40.

[0088] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is intended to cover such modifications and variations provided they come within the scope of the appended claims and their equivalents. [Explanation of symbols]

[0089] 10. Glass manufacturing equipment 40 Delivery container 42 Molded body 44 Outlet conduit 50 Inlet conduit 90 Delivery Pipe System 100 drain assembly 140 Drain pipe 142 Inlet end 144 Outlet end 150a First cooling device 160 heating elements

Claims

1. 1. A glass manufacturing apparatus comprising: a delivery conduit system configured to convey a flow of molten glass from a delivery vessel to a forming body, the delivery conduit system comprising: an outlet conduit extending from the delivery vessel; an inlet conduit extending from the molding; a drain assembly coupled between the outlet conduit and the inlet conduit, the drain assembly including a downwardly extending drain pipe having an inlet end and an outlet end; a first cooling device positioned adjacent to the delivery conduit system between the drain pipe and the forming body; a heating device configured to heat the outlet end of the drain pipe; A glass manufacturing apparatus comprising:

2. The glass manufacturing apparatus of claim 1 , wherein the heating device comprises a pair of electrical flanges attached to the drain pipe.

3. 3. The glass manufacturing apparatus of claim 1 or 2, wherein the drain assembly comprises a first curved conduit section configured to direct the flow of the molten glass from a first direction to a second direction different from the first direction.

4. 4. The glass manufacturing apparatus of claim 3, wherein the first curved conduit section comprises a first curved conduit portion and a second curved conduit portion, each of the first curved conduit portion and the second curved conduit portion configured to direct the flow of molten glass through a 90 degree turn.

5. 5. The glass manufacturing apparatus of claim 4, wherein the first curved conduit section comprises a first straight conduit portion coupled between the first curved conduit portion and the second curved conduit portion.

6. 6. The glass manufacturing apparatus of claim 5, wherein the drain pipe is coupled to the first straight conduit section.

7. The glass manufacturing apparatus of claim 5 further comprising a second curved conduit section coupled to the first curved conduit section.

8. 4. The glass manufacturing apparatus of claim 3, wherein an inner diameter of the outlet conduit is smaller than an inner diameter of the first curved conduit section.

9. 4. The glass manufacturing apparatus of claim 3, wherein the inlet conduit has an inner diameter that is smaller than the inner diameter of the first curved conduit section.

10. 8. The glass manufacturing apparatus of claim 7, wherein the second curved conduit section is coupled to the inlet conduit, and the inlet conduit has an inner diameter smaller than an inner diameter of the second curved conduit section.

11. 1. A glass manufacturing apparatus comprising: a delivery vessel; a forming body; and a delivery conduit system configured to convey a flow of molten glass from the delivery vessel toward the forming body, the delivery conduit system comprising: an outlet conduit extending downwardly from the delivery vessel; an inlet conduit extending from the molding; a drain assembly coupled between the outlet conduit and the inlet conduit, the drain assembly including a first curved conduit section and a second curved conduit section disposed downstream of the first curved conduit section with respect to a flow direction of the molten glass; a drain pipe extending downward from the drain assembly, the drain pipe including a proximal end attached to the drain assembly and a distal end opposite the proximal end; a first cooling device disposed downstream from the first curved conduit section and configured to cool at least a portion of the delivery conduit system downstream from the first curved conduit section; a heating device configured to heat the distal end of the drain pipe; A glass manufacturing apparatus comprising:

12. 1. A method of draining a delivery conduit system, comprising: flowing molten glass from a delivery vessel to a forming body through a delivery conduit system, the delivery conduit system including an outlet conduit connected to the delivery vessel, an inlet conduit connected to the forming body, and a drain assembly connected between the outlet conduit and the inlet conduit, the drain assembly including a drain pipe connected to the drain assembly, the drain pipe having a proximal end attached to the drain assembly and a distal end opposite the proximal end, the drain pipe including a first material plug disposed therein that blocks flow of the molten glass from the distal end; heating the distal end of the drain pipe to remove the first plug of material and allow the molten glass to flow from the distal end; cooling the molten glass in a portion of the delivery conduit system downstream from the drain pipe to form a second plug of material in the delivery conduit system and reduce the flow of the molten glass to the forming body; A method comprising:

13. The method of claim 12 further comprising cooling the molten glass in at least a portion of the outlet conduit with a second cooling device.

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