Glass manufacturing apparatus

Abstract

A glass manufacturing apparatus is disclosed comprising a vessel configured to deliver molten glass; a conduit extending from the vessel, the conduit including a distal end having a concave heating member connected thereto; a first electrical flange connected to the conduit; and a second electrical flange connected to the concave heating member. A method of preventing devitrification of a molten glass forming material is also described.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 113,009, filed November 12, 2020, pursuant to 35 USC § 119, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure generally relates to glass manufacturing equipment, and more specifically, to glass manufacturing equipment for delivering molten materials, such as molten glass, to, for example, glass forming equipment. Background Technology

[0004] The glass manufacturing process can be divided into three stages: melting, in which the raw material is heated to form a molten glass forming material; clarification, in which gaseous inclusions (such as bubbles) are removed from the molten glass forming material; and heat conditioning. After heat conditioning, the molten glass forming material is delivered to the forming equipment through an outlet pipe. The molten material exiting the outlet pipe should have a temperature distribution that provides the appropriate forming viscosity for the molten glass forming material.

[0005] If the viscosity (e.g., temperature) of the molten glass forming material is not properly maintained in the outlet conduit, particularly at the outlet of the outlet conduit, the molten glass forming material may become devitrified. That is, devitrification will occur if the temperature of the molten glass forming material remains below the devitrification temperature for a sufficiently long period of time. Summary of the Invention

[0006] The following is a simplified summary of this disclosure to provide a basic understanding of some of the embodiments described in the detailed description. These and other features, aspects, and advantages can be better understood when the following detailed description is read in conjunction with the accompanying drawings.

[0007] In some glass manufacturing processes, molten glass forming material is delivered from a delivery system, such as a delivery container, to downstream processes, such as forming equipment configured to shape the molten material into glass articles. Typically, the molten glass forming material is delivered via a conduit, from which it exits through an outlet orifice. In various embodiments, the temperature of the molten glass forming material, and therefore its viscosity, is maintained at a suitable temperature to facilitate uniform delivery through the conduit. For example, Figure 1 and Figure 2The diagram illustrates a vertically oriented conduit 10, which includes an upper electrical flange 12 connected to the conduit 10 and a lower electrical flange 14 connected to the conduit 10 at its outlet end 16, located below the upper electrical flange 12. Molten glass forming material 18 flows out from the outlet end 16 of the conduit. This is achieved by supplying current through the conduit between the upper electrical flange 12 and the lower electrical flange 14, thereby heating the conduit 10 between the upper electrical flange 12 and the lower electrical flange 14 by Joule heating, which in turn heats the molten glass forming material 18 within the conduit. Heating the molten glass forming material by this method is generally referred to as “direct” heating, in contrast to indirect methods using an external heat source located near the conduit, such as an electrical winding.

[0008] The electrical flange is designed to supply a large volume of current to the conduit, typically in the range of hundreds to thousands of amperes. The electrical flange is not intended to reach high temperatures and is configured with sufficient thickness to reduce its resistance and limit its temperature during operation. In some cases, the electrical flange can be cooled by cooling channels, such as cooling pipes, arranged around the outer periphery of the electrical flange (not shown). Therefore, the electrical flange, and particularly the lower electrical flange 14 at or near the discharge end of the conduit, can act as a heat sink, cooling the discharge end of the conduit. Furthermore, the location of the lower electrical flange 14 at the discharge end 16 can reduce Joule heating at the direct discharge end. If the glass-forming material at the discharge end 16 cools to a temperature below its liquid temperature and remains at the discharge end for a sufficient period, devitrification and the formation of crystallization clumps 22 (hereinafter referred to as "devitrification") may occur. If allowed to grow, crystallization clumps 22 can detach from the conduit and contaminate downstream glass-forming material. For example, during operation of a glass manufacturing apparatus, molten glass-forming material can migrate above the edge surface 20 of the conduit and above the lower electrical flange 14. This migrating glass-forming material on the edge surface and electrical flange 14 can crystallize to form deglassing 22, which can stimulate additional deglassing growth, even into the interior of the conduit.

[0009] Therefore, this document discloses a glass manufacturing apparatus, comprising: a container configured to convey molten glass; a conduit extending downward from the container, the conduit including a distal end containing a concave heating element connected thereto; a first electrical flange connected to the conduit; and a second electrical flange connected to the concave heating element. In some embodiments, the concave heating element may include a truncated cone. The concave heating element may be vertically connected to the conduit. That is, the concave heating element may intersect the conduit perpendicularly at the junction between the concave heating element and the conduit.

[0010] In various implementation examples, the concave heating element includes a secondary end and a primary end, and a second electrical flange is connected to the upper edge of the primary end.

[0011] In one embodiment, the second electrical flange may include a body portion having an inner edge defining an internal opening, the inner edge being connected to the upper edge of the concave heating member around the circumference of the main end.

[0012] In some embodiments, the glass manufacturing apparatus may further include a third electric flange connected to a conduit between the first electric flange and the molten glass delivery container.

[0013] The glass manufacturing apparatus may further include a thermally conductive material disposed in a volume between the walls of the concave heating element and the conduit. This thermally conductive material may include a ceramic binder.

[0014] In some implementations, the thickness of the conduit can be greater than the thickness T2 of the concave heating element.

[0015] In various implementations, the conduit, the concave heating element, and the second electrical flange may contain platinum, such as a platinum-rhodium alloy.

[0016] In various implementations, the conduit includes a drain pipe for the container.

[0017] In various implementations, the concave heating element can be an upwardly concave heating element.

[0018] In other embodiments, a glass manufacturing apparatus is described, comprising: a molten glass delivery container; a conduit extending from the molten glass delivery container, the conduit including a proximal end connected to the molten glass delivery container and a distal end having a tapered heating element extending from the distal end toward the molten glass delivery container; and an electrical flange connected to the tapered heating element.

[0019] The glass manufacturing equipment may further include a ceramic binder disposed in a volume between the walls of the conical heating element and the conduit.

[0020] In various implementations, the conduit, the tapered heating element, and the second electrical flange may contain platinum, such as a platinum-rhodium alloy.

[0021] In some implementations, the conical heating element may include an arched neck that is vertically connected to the distal end.

[0022] In some implementations, the thickness T1 of the conduit is greater than the thickness T2 of the conical heating element.

[0023] In other embodiments, a glass manufacturing apparatus is disclosed, comprising: a container configured to convey molten glass; a conduit extending from and in fluid communication with the container, the conduit including a proximal end connected to the container and a distal end opposite and spaced apart from the proximal end; a concave heating member connected to the conduit, the concave heating member including a primary end and a secondary end and extending about at least a portion of the length of the conduit; and an electrical flange connected at its primary end to the concave heating member. For example, the secondary end of the concave heating member may be connected to the conduit.

[0024] In some implementations, the secondary end includes an arched neck with a curvature that bends in the direction of the catheter. For example, the arched neck may be connected vertically to the catheter.

[0025] In some implementations, the secondary end of the concave heating element is connected to the distal end of the conduit.

[0026] In some implementations, the thickness T1 of the conduit is greater than the thickness T2 of the concave heating element.

[0027] In various implementations, the conduit, concave heating element, and electrical flange contain platinum, such as a platinum-rhodium alloy.

[0028] In some implementations, the concave heating element may be an upwardly recessed heating element.

[0029] In other embodiments, a method for preventing devitrification of a molten glass forming material is disclosed, comprising: flowing the molten glass forming material through a conduit including a concave heating member connected to the conduit and extending about at least a portion of the length of the conduit; establishing a current between the conduit and the concave heating member between a first electrical flange connected to the conduit and a second electrical flange connected to the concave heating member, the concave heating member conductively heating at least a portion of the length of the conduit. The concave heating member includes a primary end comprising a first diameter d1 and a secondary end opposite the primary end. The secondary end may include a second diameter d2 smaller than d1.

[0030] In some embodiments, the secondary end may include an arched neck that includes a curvature that bends toward the catheter and connects vertically to the catheter.

[0031] In some implementations, the concave heating element may be connected to the distal end of the conduit.

[0032] In some implementations, the concave heating element may be an upwardly recessed heating element.

[0033] Other features and advantages of the embodiments disclosed herein will be set forth in the following detailed description, and will be apparent in part to those skilled in the art from that description or will be recognized by practice of the embodiments described herein (including the following detailed description, claims, and drawings). It should be understood that both the foregoing general description and the following detailed description are intended to provide an overview or framework of embodiments for understanding the nature and characteristics of the embodiments disclosed herein. Drawings are included to provide further understanding and are incorporated into and form a part of this specification. The drawings illustrate various embodiments of this disclosure and, together with the description, explain their principles and operation. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a conduit and a pair of electrical flanges connected thereto for directly heating the molten glass-forming material flowing through the conduit;

[0035] Figure 2 yes Figure 1 Cross-sectional view of the conduit and electrical flange;

[0036] Figure 3 An exemplary glass forming apparatus according to an embodiment disclosed herein includes a delivery container and an outlet conduit extending therefrom, wherein an electrical flange is configured to establish current in the outlet conduit;

[0037] Figure 4 yes Figure 1 A frontal cross-sectional view of the outlet conduit, showing the concave heating element attached to the distal end of the outlet conduit;

[0038] Figure 5 yes Figure 2 A perspective view of at least a portion of the outlet conduit, showing the concave heating element;

[0039] Figure 6 This is a perspective view of an exemplary first electrical flange;

[0040] Figure 7 This is a perspective view of an exemplary second electrical flange;

[0041] Figure 8 This is a cross-sectional view of a portion of the distal end of the concave heating element and the outlet conduit, showing the skirt and arched neck vertically connected to the outlet conduit;

[0042] Figure 9 yes Figure 4 A perspective view of at least a portion of the outlet conduit, showing the attachment of a first electrical flange and a second electrical flange to the outlet conduit and an upwardly recessed heating element, respectively.

[0043] Figure 10 It is a perspective view of another concave heating element with a parabolic shape;

[0044] Figure 11 This is a cross-sectional view of a portion of an exemplary downcomer according to an embodiment described herein, wherein the downcomer is shown as delivering molten glass forming material to an exemplary forming apparatus including a rotary forming roller; and

[0045] Figure 12 This is a cross-sectional view of a portion of another exemplary downcomer according to an embodiment described herein, wherein the downcomer is shown as delivering molten glass forming material to a forming apparatus comprising a pair of counter-rotating forming rollers. Detailed Implementation

[0046] Reference will now be made in detail to embodiments of this disclosure, 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 similar parts. However, this disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0047] As used herein, the term “about” means that quantities, dimensions, formulations, parameters and other quantities and characteristics are not and need not be precise, but may be approximate and / or larger or smaller as required, reflecting tolerances, conversion factors, rounding, measurement errors and other factors known to those skilled in the art.

[0048] A range in this document may be expressed as from “about” a particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes a range from one particular value to another. Similarly, when a numerical value is expressed as an approximation using the prefix “about”, it will be understood that the particular value constitutes another embodiment. It will be further understood that the endpoints of each range are significant with respect to and independent of the other endpoint.

[0049] The directional terms used in this article—such as up, down, right, left, front, back, top, bottom—are for reference only and are not intended to imply absolute directions.

[0050] Unless otherwise expressly stated, no method described herein is intended to be construed as requiring its steps to be performed in a particular order, nor is it intended to require a particular orientation for any device. Therefore, if a method claim does not actually describe the order in which its steps should be followed, or any device claim does not actually describe the order or orientation of individual components, or if the claims or description do not specifically state that the steps should be limited to a particular order, or do not describe a particular order or orientation of the device's components, then no order or orientation is intended to be inferred in any way. This applies to any possible non-explicit basis of interpretation, including logical matters concerning the arrangement of steps, the flow of operations, the order of components, or the orientation of components; the general meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0051] As used herein, unless the context explicitly states otherwise, the singular forms “a / an” and “the” contain plural referents. Thus, for example, unless the context explicitly indicates otherwise, a reference to the “a” component includes aspects having two or more such components.

[0052] The terms “exemplary,” “implementation,” or their various forms are used herein to serve as examples, instances, or illustrations. No aspect or design described herein as “exemplary” or “implementation” should be construed as preferred or advantageous over other aspects or designs. Furthermore, embodiments are provided merely for clarity and understanding and are not intended to limit or constrain the disclosed subject matter or relevant portions of this disclosure in any way. It will be understood that numerous additional or alternative embodiments of a different scope may be presented, but these embodiments are omitted for brevity.

[0053] As used herein, unless otherwise stated, the terms “including” and “contains” and their variations shall be interpreted as synonymous and open-ended. The list of elements following the transitional phrase “including” or “contains” is a non-exclusive list, and thus may include elements other than those specifically listed in the list.

[0054] As used herein, the terms “substantial,” “largely,” and their variations are intended to indicate that the described feature is equal to or approximately equal to a certain value or description. For example, a “largely planar” surface is intended to mean a surface that is planar or approximately planar. Furthermore, “largely” is intended to mean that two numerical values ​​are equal or approximately equal. In some embodiments, “largely” may mean that the numerical values ​​are within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

[0055] As used herein, the terms "electrical connection," "electrical connection," and variations thereof refer to a connection via an electrical conductor, such as a metallic conductor, but excluding molten material (e.g., molten glass). A first element electrically connected to a second element may include an additional element between the first and second elements, such that the additional element is also electrically connected to both the first and second elements. That is, an electrical connection between the first and second elements does not preclude the presence of other conductive elements in the connection. Typically, such an electrical conductor may include, but is not limited to, metal wires or cables, busbars, etc. An electrical connection may also include other elements, including but not limited to electrical connectors (e.g., plugs, adjusting tabs, lugs, bolts, etc.) that facilitate connection between elements, electrical control devices (such as current and / or voltage controllers), current and / or voltage measuring devices, etc.

[0056] As used in this article, “refractory material” refers to a non-metallic material with chemical and physical properties that make it suitable for structures exposed to environments above 538°C, or as a component of a system.

[0057] As used in this article, "cone" includes straight cones, oblique cones, and truncated cones.

[0058] Unless otherwise stated, the figures are not drawn to scale.

[0059] exist Figure 3 An exemplary glass manufacturing apparatus 100 is illustrated. In some embodiments, the glass manufacturing apparatus 100 may include a glass melting furnace 102 comprising a melting vessel 104. In addition to the melting vessel 104, the glass melting furnace 102 may optionally include one or more additional components, such as heating elements (e.g., burners and / or electrodes) configured to heat the raw material and convert it into molten glass. For example, the melting vessel 104 may be an electrically assisted melting vessel, wherein energy is added to the raw material via a burner and by direct heating, wherein an electric current passes through the raw material, and the current thus adds energy through Joule heating of the raw material.

[0060] In a further embodiment, the glass melting furnace 102 may include other thermal management devices (e.g., insulation components) to reduce heat loss from the melting vessel. In still further embodiments, the glass melting furnace 102 may include electronic and / or electromechanical devices to facilitate the melting of raw materials into molten glass. The glass melting furnace 102 may include a support structure (e.g., a support chassis, support members, etc.) or other components.

[0061] The melting container 104 may be formed of a refractory material, such as a refractory ceramic material, for example, a refractory ceramic material comprising alumina and / or zirconium oxide, but the refractory ceramic material may include other refractory materials, such as yttrium (e.g., yttrium oxide, yttrium oxide-stabilized zirconium oxide, yttrium phosphate), zircon (ZrSiO4), or alumina-zirconia-silica or even chromium oxide, used alternately or in any combination. In some embodiments, the melting container 104 may be constructed of refractory ceramic bricks.

[0062] In some embodiments, the glass melting furnace 102 may be incorporated as a component of a glass manufacturing apparatus configured to manufacture glass articles, such as glass ribbons. However, in further embodiments, the glass manufacturing apparatus may be configured to form other glass articles without limitation, such as glass rods, glass tubes, glass sleeves (e.g., for lighting fixtures, such as light bulb sleeves), and glass lenses, but many other glass articles are also contemplated. In some embodiments, the melting furnace may be included in a glass manufacturing apparatus that includes a channel drawing apparatus, a floating bath apparatus, a down-drawing apparatus (e.g., a melt down-drawing apparatus), an up-drawing apparatus, a pressing apparatus, a rolling apparatus, a tube drawing apparatus, or any other glass manufacturing apparatus that would benefit from the present disclosure. For example, Figure 3 The illustration schematically depicts a glass melting furnace 102 as a component of a molten-draw glass manufacturing apparatus 100, used to melt and draw glass strips for subsequent processing into individual glass sheets or to wind the glass strips onto a spool. As used herein, molten drawing involves flowing molten glass over the side surface of a molded body, wherein the resulting flow of molten material joins, or “fuses,” at the bottom of the molded body.

[0063] Glass manufacturing apparatus 100 may optionally include upstream glass manufacturing apparatus 106 located upstream of melting vessel 104. In some embodiments, a portion or all of upstream glass manufacturing apparatus 106 may be incorporated as part of glass melting furnace 102.

[0064] like Figure 3As illustrated in the embodiment, upstream glass manufacturing equipment 106 may include a raw material storage bin 108, a raw material delivery device 110 (e.g., an auger or screw feeder), and a motor 120 connected to the raw material delivery device 110. The raw material storage bin 108 may be configured to store a quantity of raw material 122, which may be fed into a melting vessel 104 through one or more inlets, as indicated by arrow 124. The raw material 122 typically comprises one or more glass-forming metal oxides and one or more modifiers. In some embodiments, the raw material delivery device 110 may be powered by the motor 120 to deliver a predetermined amount of raw material 122 from the raw material storage bin 108 to the melting vessel 104. In a further embodiment, the motor 120 may power the raw material delivery device 110 to introduce the raw material 122 at a controlled rate based on the level of molten material sensed downstream of the melting vessel 104 relative to the flow direction of the molten material. The raw material 122 within the melting vessel 104 may be heated to form molten glass forming material 126. Typically, in the initial melting step, the raw material is added to the melting vessel in granular form, such as various types of "sand" or powder. Raw material 122 may also contain shards of glass (glass chips) from previous melting and / or forming operations. A burner is typically used to initiate the melting process. In electrically assisted melting, once the resistance of the raw material has been sufficiently reduced, electrical heating can be initiated by creating a potential between electrodes positioned in contact with the raw material, thereby driving a current through the material, which typically enters or is in a molten state. As used herein, the resulting molten glass forming material is referred to as molten glass 126.

[0065] Glass manufacturing apparatus 100 may optionally include downstream glass manufacturing apparatus 128 positioned downstream of glass melting furnace 102 relative to the flow direction of molten glass 126. In some embodiments, a portion of downstream glass manufacturing apparatus 128 may be incorporated as part of glass melting furnace 102. However, in some cases, the first connecting conduit 130 discussed below or other portions of downstream glass manufacturing apparatus 128 may be incorporated as part of glass melting furnace 102.

[0066] Downstream glass manufacturing equipment 128 may include a first conditioning (e.g., processing) chamber, such as a refining container 132, located downstream of the melting vessel 104 and connected to the melting vessel 104 via the aforementioned first connecting conduit 130. In some embodiments, molten glass 126 may be gravity-fed from the melting vessel 104 to the refining container 132 via the first connecting conduit 130. For example, gravity may drive the molten glass 126 through the internal channels of the first connecting conduit 130 from the melting vessel 104 to the refining container 132. Thus, the first connecting conduit 130 provides a flow path for the molten glass 126 from the melting vessel 104 to the refining container 132. However, it should be understood that other conditioning chambers may be located downstream of the melting vessel 104, for example, between the melting vessel 104 and the refining container 132. In some embodiments, a conditioning chamber may be employed between the melting vessel and the refining container. For example, molten glass from the primary melting vessel can be further heated in the secondary conditioning vessel, or cooled in the secondary conditioning vessel to a temperature lower than that of the molten glass in the primary melting vessel, before entering the refining chamber.

[0067] Gaseous inclusions can be removed from the molten glass 126 using various techniques. For example, the feedstock 122 may contain a multivalent compound (e.g., a clarifying agent), such as tin oxide, which undergoes a chemical reduction reaction upon heating and releases oxygen. Other suitable clarifying agents include, but are not limited to, arsenic, antimony, iron, and cerium, but the use of arsenic and / or antimony may be discouraged for environmental reasons. The clarifying vessel 132 may be heated, for example, to a temperature greater than that of the molten vessel, thereby heating the clarifying agent. Oxygen generated by the temperature-induced chemical reduction of one or more clarifying agents contained in the molten glass rises through the molten glass in the clarifying vessel and may condense or diffuse into bubbles generated during the melting process. The enlarged bubbles, with increased buoyancy, then rise to the free surface of the molten glass in the clarifying vessel and can subsequently be discharged from the clarifying vessel.

[0068] The downstream glass manufacturing apparatus 128 may further include another conditioning chamber, such as a mixing device 134, or a stirring vessel, for mixing the molten glass flowing downstream from the refining vessel 132. The mixing device 134 can be used to provide a homogeneous glass melt composition, thereby reducing chemical or thermal inhomogeneities that might otherwise be present in the molten glass leaving the refining chamber. As shown, the refining vessel 132 can be connected to the mixing device 134 by means of a second connecting conduit 136. In some embodiments, the molten glass 126 can be gravity-fed from the refining vessel 132 to the mixing device 134 by means of the second connecting conduit 136. For example, gravity can drive the molten glass 126 through the internal channels of the second connecting conduit 136 from the refining vessel 132 to the mixing device 134. Typically, the molten glass in the mixing device 134 comprises a free surface, with a free volume extending between the free surface and the top of the mixing device. Although the mixing device 134 is shown downstream of the refining vessel 132 relative to the flow direction of the molten glass, in other embodiments, the mixing device 134 may be positioned upstream of the refining vessel 132. In some embodiments, the downstream glass manufacturing apparatus 128 may include multiple mixing devices, such as a mixing device upstream of the refining vessel 132 and a mixing device downstream of the refining vessel 132. When in use, the multiple mixing devices may have the same design, or they may have different designs from each other. In some embodiments, one or more containers and / or conduits may contain static mixing blades positioned therein to facilitate mixing and subsequent homogenization of the molten material.

[0069] The downstream glass manufacturing apparatus 128 may further include another regulating chamber, such as a delivery container 138 located downstream of the mixing apparatus 134. The delivery container 138 regulates the flow of molten glass 126 to be fed into the downstream forming apparatus. For example, the delivery container 138 may act as an accumulator and / or flow controller to regulate and / or provide a consistent flow rate of molten glass 126 to the downstream process via an outlet conduit (hereinafter referred to as downcomer 140). In some embodiments, the molten glass 126 in the delivery container 138 may include a free surface from which a free volume extends upward to the top of the delivery container. As shown, the mixing apparatus 134 may be coupled to the delivery container 138 via a third connecting conduit 142. In some embodiments, the molten glass 126 may be gravity-fed from the mixing apparatus 134 to the delivery container 138 via the third connecting conduit 142. For example, gravity may drive the molten glass 126 through the internal channels of the third connecting conduit 142 from the mixing apparatus 134 to the delivery container 138.

[0070] Now for reference Figure 4 and Figure 5The downcomer 140 includes a proximal end 144 coupled to and in fluid communication with a delivery container 138, and a distal end 146 opposite to and spaced apart from the proximal end 144 along a central longitudinal axis 148 of the downcomer 140. The wall 150 of the downcomer 140 includes an inner surface 154 and an outer surface 156, defining an internal channel 157 extending between the proximal end 144 and the distal end 146. Gravity can drive molten glass 126 through the internal channel 157 from the delivery container 138 to the distal end 146 of the downcomer 140, and the molten glass can then be delivered from the distal end 146 to a forming apparatus 158. For example, the molten glass 126 can be delivered to a pull-down glass forming apparatus (e.g., a channel-draw glass forming apparatus, overflow pull-down), a float glass forming apparatus, or a rolled glass forming apparatus, but in a further embodiment, the molten glass 126 can be delivered to any other glass forming apparatus known in the art.

[0071] like Figure 4 As shown, downcomer 140 is connected to a first electrical flange 160 and electrically connected to a second electrical flange 162 via a concave heating member 164. The first and second electrical flanges 160 and 162 are configured to supply current to downcomer 140. For example, a current can be established in wall 150 between the first and second electrical flanges 160 and 162, heating wall 150 to heat and / or maintain the temperature of the molten glass flowing through the portion of downcomer 140 between the first and second electrical flanges 160 and 162. The first electrical flange 160 is located upstream of the second electrical flange 162, but in a further embodiment, the first electrical flange may be connected to a delivery container 38.

[0072] refer to Figure 6 The first electrical flange 160 includes a first body portion 166 and a first electrode portion 168 extending from the first body portion 166. The first body portion 166 includes an inner edge 170 defining an opening 172 passing through the first body portion 166.

[0073] Turning Figure 7 The second electrical flange 162 includes a second body portion 174 and a first electrode portion 176a. In some embodiments, such as the illustrated embodiment, the second electrical flange 162 may include a second electrode portion 176b, wherein the first electrode portion 176a is disposed on the second body portion 174 opposite to the second electrode portion 176b, such that the electrode portions 176a and 176b are spaced 180 degrees apart. The second body portion 174 further includes an inner edge 180 defining an opening 182 passing through the second body portion 174 and an outer peripheral edge 178 surrounding a circumference of the body portion. In various embodiments, the first body portion 166 and / or the second body portion 174 may be planar or generally planar.

[0074] Although not shown, in a further embodiment, the first electrical flange may include a second electrode portion opposite to the first electrode portion 168. Similarly, the second electrical flange 162 may include an electrode portion in the manner shown for the first electrical flange 160. Using multiple electrode portions, such as opposing electrode portions, can make the current delivered to the components connected to the electrical flanges more uniform around the circumference of the components at the connection point.

[0075] In some implementations, one or more additional electrical flanges may be connected to the downcomer 140 between the first electrical flange 160 and the delivery container 138. For example, Figure 3 and Figure 4 The illustration shows a third electrical flange 184 attached to the downcomer 140 and positioned above the first electrical flange 160, for example, between the first electrical flange 160 and the delivery container 138. According to some embodiments, the third electrical flange 184 may be similar to or identical to the first electrical flange 160. The third electrical flange 184 may have a single electrode portion or multiple electrode portions. Each electrical flange may be electrically connected to a power supply (not shown) and configured to deliver current to the electrical flange. The power supply may be a local power grid, such as a substation, or a separate generator.

[0076] Back Figure 4 and Figure 5 In some embodiments, the concave heating member 164 may extend upward from the distal end 146 of the downcomer 140. That is, the concave heating member 164 may be a concave heating member. The concave heating member 164 may include a skirt 186, which includes a circular cross-section in a plane orthogonal to the longitudinal axis 148, but in a further embodiment, the heating member 164 may have a non-circular cross-sectional shape. The upper opening 188 is defined by the upper edge 190 of the concave heating member 164, which has a first diameter d1. The concave heating member 164 also includes a second lower opening 192 defined by a second lower edge 194, which has a second diameter d2 smaller than the first diameter d1. The end of the concave heating member 164 with the largest opening, i.e., the upper opening 188, is defined as the primary end 196, while the end of the upwardly recessed heating member 164 with the smaller opening, i.e., the second opening 192, is defined as the secondary end 198. In some embodiments, the concave heating member 164 may be tapered, for example, including a tapered skirt 186. In various embodiments, the secondary end 198 of the upwardly recessed heating member 164 may include an arched neck 200 (see...). Figure 8 The neck 200 includes curvature in the direction of the longitudinal axis 148. That is, the bow-shaped neck 200 curves inward toward the downcomer 140 and includes a lower edge 194.

[0077] The inner edge 180 of the second electric flange 162 is attached to the upper edge 190 of the concave heating member 164, such as by welding, and the lower edge 194 of the concave heating member 164 is attached to the distal end 146 or near the distal end of the downcomer 140. Thus, a cup-shaped volume with a closed bottom is formed between the concave heating member 164 and the wall 150.

[0078] In some implementations, it is best as shown Figure 5 Region A Figure 8As shown, the lower edge 194 can be attached a short distance δ above the distal end 146 to allow sufficient clearance between the welds 195 used to connect the lower edge 194 to the wall 150. That is, a welding operation that directly connects the lower edge 194 to the downcomer 140 at the distal end 146 would deform the distal end 146, potentially disrupting the flow of molten glass from the distal end 146. Therefore, the lower edge 194 of the concave heating member 164 can be slightly moved above the distal end 146, for example, where δ is in the range of about 1 mm to about 3 mm, such as between about 1 mm and about 1.5 mm, or in the range greater than 0 mm but equal to or less than about 1 mm. Thus, as used herein, references to the concave heating member connected to the distal end 146 of the conduit include the length of the conduit within 3 mm of the distal end. The arched neck 200 can be arranged such that the arched neck is orthogonal to the wall 150 at the intersection of the lower edge 194 and the wall 150. The orthogonality between the concave heating element 164 and the downcomer 140 helps maintain a consistent thickness of the concave heating element 164 and avoids potential resistance variations within the concave heating element 164. In other words, in different embodiments, the wall 150 of the downcomer 140 may include a substantially uniform thickness T1. On the other hand, the concave heating element 164 may have a thickness T2 equal to or less than T1. The current density through a conductor is a function of the magnitude of the current and the cross-sectional area of ​​the conductor. The resistance of the downcomer 140 is proportional to the length of the conductor divided by its cross-sectional area. That is, assuming uniform thickness, the resistance R of the downcomer 140 or a selected portion thereof is the length L of the downcomer or a selected portion thereof divided by the cumulative cross-sectional area A in the plane perpendicular to the longitudinal axis 148 (R∝L / A). The current I in the downcomer 140 is I=E / R, where E is the voltage across the length L and R is the resistance. It should be apparent that, in the plane orthogonal to the longitudinal axis 148, d1 is larger than d2 at each cross-section of the upwardly concave heating element 164. In fact, d2 increases as the cross-section of the concave heating element 164 approaches its upper edge 190. If the thickness T2 of the concave heating element 164 is greater than T1, then the cross-sectional area A2 of the concave heating element 164 at any cross-section is greater than the cross-sectional area A1 of the corresponding cross-section of the downcomer 140. Therefore, the current density in the concave heating element 164, and the heat power generated by the concave heating element, will be reduced. Therefore, in various embodiments, the T2 of the skirt 186 is less than the thickness T1 of the wall 150, where the thicknesses T1 and T2 are both measured as the shortest distance between the opposing surfaces of the respective components (e.g., the distance between opposing surfaces along a line orthogonal to the opposing surfaces, such as the orthogonal distance between the inner surface 154 and the outer surface 156 of the downcomer 140). If the concave heating element 164 intersects the downcomer 140 at an angle other than 90 degrees, the cross-sectional area of ​​the concave heating element at the intersection with the downcomer 140 will be different from the cross-sectional area of ​​the concave heating element elsewhere in the concave heating element.

[0079] Figure 9 This is a perspective view of the downcomer 140, wherein a first electrical flange 160 is connected to the downcomer, a concave heating element 164 is connected to the distal end of the downcomer, and a second electrical flange 162 is connected to the concave heating element 164. In the illustrated embodiment, the concave heating element 164 is arranged as an upwardly recessed heating element, for example, a tapered heating element.

[0080] Back Figure 4 The thermally conductive material 202 may be disposed in a cup-shaped volume 204 between the concave heating member 164 and the wall 150. However, the thermally conductive material 202 should be electrically insulated (non-conductive) to prevent electrical short circuits across the upwardly recessed heating member 164. The thermally conductive material 202 may include a castable ceramic binder, such as Ceramabond 503 available from Aremco Products, Inc. (Valley Cottage, NY), EA139 manufactured by Saint-Gobain Abrasives Incorporated, or, for example, a mixture of Ceramabond and EA139.

[0081] The function of the thermally conductive material 202 is to conduct the heat generated by the current in the concave heating member 164 (between the first electric flange 160 and the second electric flange 162) to the portion of the downcomer 140 that contacts the thermally conductive material 202. Furthermore, because the thickness T2 of the concave heating member 164 can be very thin, the thermally conductive material 202 provides structural rigidity to the concave heating member, thereby preventing deformation or collapse of the upwardly recessed heating member. The dimensions of the concave heating member 164 (e.g., height, diameter, thickness), and the magnitude of the current supplied between the first electric flange 160 and the second electric flange 162, are selected to provide sufficient thermal energy to the distal end 146 such that the molten glass migrating to the edge surface of the distal end 146 or the outer surface of the concave heating member 164 is maintained at a temperature above the liquid temperature of the molten glass. Therefore, the distal end 146 can be heated by conduction through the concave heating member 164 and directly heated by the wall 150 due to Joule heating.

[0082] According to various embodiments, a first insulation material 206 may be disposed between the first electrical flange 160 and the second electrical flange 162, for example, between the first body portion 166 and the second body portion 174. The first insulation material may be, for example, ceramic fiberboard (e.g., aluminosilicate / or mullite fiber and binder), such as Unifrax Fiberfrax® Duraboard® 3000 or ZIRCAR RS-100 refractory board manufactured by ZIRCAR Refractory Composites, Incorporated. In some embodiments, a second insulation material 207 may also be disposed between the first electrical flange 160 and the second electrical flange 162. The second insulation material 207 may be, for example, refractory brick suitable for supporting the weight of insulating or other materials positioned above the first electrical flange 160. The second insulation material 207 may include alumina and / or zirconium oxide, but may employ other refractory brick materials known in the art.

[0083] In some embodiments, a third insulation material 208 may be positioned below and in contact with the second electrical flange 162. The third insulation material 208 may be the same material as the first insulation material 206, such as ceramic fiberboard, like Unifrax Fiberfrax® Duraboard® 3000 and / or ZIRCAR RS-100 fire-resistant board. The third insulation material 208 may define a channel 210 of sufficient diameter to allow the molten glass flow from the distal end 146 of the downcomer 140 to pass through the third insulation material 208 without contacting the first insulation material 208.

[0084] A fourth insulating material 212, such as a castable refractory material, may surround the downcomer 140. Furthermore, in some embodiments, a fifth insulating material 214, such as refractory brick, may surround the fourth insulating material 212. The fifth insulating material 214 may include, for example, alumina and / or zirconium oxide, but other refractory materials may also be used.

[0085] Components of the downstream glass manufacturing apparatus 128, including connecting conduits 130, 136, 142, a clarifying vessel 132, a mixing device 134, a delivery vessel 138, a downcomer 140, or any one of electrical flanges 160, 162, or 184, may be formed of precious metals. Suitable precious metals include platinum group metals selected from the group consisting of platinum, iridium, rhodium, osmium, ruthenium, and palladium, or alloys thereof. For example, downstream components of the glass manufacturing apparatus may be formed of or contain platinum-rhodium alloys comprising about 70 wt% to about 90 wt% platinum and about 10 wt% to about 30 wt% rhodium. However, other metals suitable for forming downstream components of the glass manufacturing apparatus may include molybdenum, rhenium, tantalum, titanium, tungsten, and alloys thereof.

[0086] The downcomer 140, the fourth insulation material 212, and the fifth insulation material 214 may be supported by one or more steel structural members 216 arranged around the periphery of the fifth insulation material 214.

[0087] In a further embodiment, the concave heating member 164 may include, for example: Figure 10 The parabolic shape shown results in a bowl-shaped volume positioned between the concave heating element 164 and the outer surface 156 of the downcomer wall 150. However, the concave heating element 164 may have other concave shapes, such as a hemispherical shape.

[0088] Figure 3 Further illustrated is an exemplary embodiment of forming equipment 158, which includes one or more forming rollers 218 arranged to produce glass ribbons 220. For example, in some embodiments, such as Figure 11 As illustrated, the forming apparatus may include a single forming roller 218 arranged to rotate about a rotation axis, wherein molten glass 126 is delivered to the top portion of the forming roller 218 through a downcomer 140. The molten glass rotates together with the forming roller and is released as a glass ribbon 220 near the bottom of the forming roller 218. In another embodiment, as shown... Figure 12 As shown, molten glass is delivered through a downcomer 140 between a first rotary forming roll 218a and a second counter-rotating rotary forming roll 218b spaced apart from the first rotary forming roll 218a. The molten glass is pressed between the two counter-rotating rotary forming rolls and exits as a glass strip 220 between the two counter-rotating rotary forming rolls.

[0089] Concave heating elements do not require connection to conduits intended for conveying molten glass to forming equipment. For example, various containers (or conduits) in glass manufacturing equipment may need to be drained at some point in their operation. Therefore, these containers can be equipped with drain pipes, which can be fitted with concave heating elements as described herein, connected to electrical flanges as described with respect to the aforementioned downcomer. Furthermore, in some embodiments, concave heating elements similar to those described herein can be used at any location on the conduit requiring additional heat energy, and are therefore not limited to upward concavity (e.g., connection to a vertically arranged conduit or pipe), but can be oriented in other directions. Moreover, concave heating elements are not limited to the ends of pipes or conduits, but can be arranged as part of the middle portion of a pipe or conduit.

[0090] While various embodiments have been described in detail with respect to certain illustrative and specific examples thereof, this disclosure should not be considered limited thereto, as many modifications and combinations of the disclosed features may be made without departing from the scope of the appended claims.

Claims

1. A glass manufacturing apparatus, comprising: The container is configured to transport molten glass; A conduit extending downward from the container, the conduit including a distal end, the distal end including a concave heating member connected thereto; A first electrical flange is connected to the conduit; and The second electrical flange is connected to the concave heating element. The concave heating member includes a secondary end and a primary end, and extends around at least a portion of the length of the conduit, with the second electrical flange connected to the upper edge of the primary end. The thickness T1 of the conduit is greater than the thickness T2 of the concave heating member. The concave heating member includes a main end with a first diameter d1 and a secondary end opposite to the main end, the secondary end including a second diameter d2 smaller than d1.

2. The glass manufacturing apparatus according to claim 1, wherein the concave heating member comprises a truncated cone.

3. The glass manufacturing apparatus of claim 1, wherein the second electric flange includes a body portion having an inner edge defining an internal opening, the inner edge being connected to the upper edge of the concave heating member around the periphery of the main end.

4. The glass manufacturing apparatus of claim 1, further comprising a third electric flange electrically connected to a conduit between the first electric flange and the molten glass delivery container.

5. The glass manufacturing apparatus according to claim 1, wherein the concave heating member intersects the conduit perpendicularly.

6. The glass manufacturing apparatus of claim 1, further comprising a thermally conductive material disposed within a volume defined between the concave heating member and the wall of the conduit.

7. The glass manufacturing apparatus of claim 6, wherein the thermally conductive material comprises a ceramic binder.

8. The glass manufacturing apparatus according to claim 1, wherein the conduit, the concave heating member, and the second electrical flange contain platinum.

9. The glass manufacturing apparatus of claim 1, wherein the conduit comprises the drain pipe of the container.

10. The glass manufacturing apparatus according to claim 1, wherein the concave heating member is an upwardly recessed heating member.

11. A glass manufacturing apparatus, comprising: Molten glass delivery container; A conduit extending from the molten glass delivery container, the conduit including a proximal end connected to the molten glass delivery container and a distal end having a tapered heating member extending from the distal end toward the molten glass delivery container; and The second electrical flange connected to the conical heating element The thickness T1 of the conduit is greater than the thickness T2 of the conical heating member.

12. The glass manufacturing apparatus of claim 11, further comprising a ceramic adhesive disposed within a volume defined between the conical heating member and the wall of the conduit.

13. The glass manufacturing apparatus of claim 11, wherein the conduit, the tapered heating element, and the second electrical flange contain platinum.

14. The glass manufacturing apparatus of claim 13, wherein the conical heating member includes an arched neck vertically connected to the distal end.

15. A glass manufacturing apparatus, comprising: The container is configured to transport molten glass; A conduit extending from and in fluid communication with the container, the conduit including a proximal end connected to the container and a distal end opposite to and spaced apart from the proximal end; A concave heating member connected to the conduit, the concave heating member including a main end and a secondary end, and extending around at least a portion of the length of the conduit; and An electrical flange is connected to the concave heating element at its main end. The thickness T1 of the conduit is greater than the thickness T2 of the concave heating member. The concave heating member includes a main end with a first diameter d1 and a secondary end opposite to the main end, the secondary end including a second diameter d2 smaller than d1.

16. The glass manufacturing apparatus of claim 15, wherein the secondary end of the concave heating member is connected to the conduit.

17. The glass manufacturing apparatus of claim 15, wherein the secondary end includes an arched neck having a curvature bending in the direction of the conduit.

18. The glass manufacturing apparatus of claim 17, wherein the arched neck is vertically connected to the conduit.

19. The glass manufacturing apparatus of claim 15, wherein the secondary end of the concave heating member is connected to the distal end of the conduit.

20. The glass manufacturing apparatus of claim 15, wherein the conduit, the concave heating element, and the electrical flange contain platinum.

21. The glass manufacturing apparatus according to any one of claims 15 to 20, wherein the concave heating member is an upwardly recessed heating member.

22. A method for preventing devitrification of a molten glass forming material, comprising: The molten glass forming material is flowed through a conduit, the conduit including a concave heating member connected to the conduit and extending around at least a portion of the length of the conduit; In the conduit and the concave heating member, a current is established between a first electrical flange connected to the conduit and a second electrical flange connected to the concave heating member, wherein the concave heating member conductively heats at least a portion of the length of the conduit. The concave heating element includes a secondary end and a primary end, and the second electrical flange is connected to the upper edge of the primary end. The thickness T1 of the conduit is greater than the thickness T2 of the concave heating member. The concave heating member includes a main end with a first diameter d1 and a secondary end opposite to the main end, the secondary end including a second diameter d2 smaller than d1.

23. The method of claim 22, wherein the secondary end includes an arched neck that includes a curvature bending in a direction toward the catheter and is perpendicularly connected to the catheter.

24. The method of claim 22, wherein the concave heating member is connected to the distal end of the conduit.

25. The method according to any one of claims 22 to 24, wherein the concave heating member is an upwardly recessed heating member.

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