Continuous cold crown induction glass melter

Abstract

The invention relates to a continuous cold crown induction glass melter. An inductive glass melting system for producing glass includes a vertical melting tank to contain batch material for melting and molten glass. The system also includes a batch material feeder for feeding batch material to the melting tank at a top side of the melting tank, and a glass melt outlet for discharging the resulting glass melt at a bottom side of the melting tank. The system includes a multi-zone heating system having a plurality of induction coils around the perimeter of the melting tank to independently heat a plurality of heating zones vertically along the height of the melting tank. The system comprises in-situ monitoring and realizes a continuous cold crown melting process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority under 35 U.S.C. §119 to U.S. Provisional Application Serial No. 63 / 553,463, filed on February 14, 2024, the contents of which are relied upon and incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates generally to induction glass melting systems and methods, and more particularly to cold crown induction glass melting systems and methods for achieving continuous glass melting. Background Art

[0004] Glassmaking is an energy-intensive industry. On average, the glass industry generates 0.6 tons of CO₂ for every ton of glass produced. Companies seek to reduce greenhouse gas emissions through their sustainability efforts primarily from two sources, sometimes referred to as Scope 1 and Scope 2 greenhouse gas emissions. Scope 1 includes direct greenhouse gas emissions from sources owned or controlled by the company. Scope 2 includes indirect greenhouse gas emissions from electricity, steam, heating, or cooling purchased by the company. Global companies have pledged to reduce both types of emissions. For melting glass batch materials in glassmaking, there are currently two main technologies that can reduce emissions: hydrogen burners and all-electric glass melting.

[0005] Two types of glass melting techniques include hot crown melting and cold crown melting. In hot crown melting, the glass is heated from above by gas burners and also heated from below by, for example, electrodes. Batch material is fed from one end of the melting tank to form a pile of batch material on the glass melt, which typically covers a small portion of the melt's surface. In cold crown melting, there is no heat from above the batch material. Batch material can be fed from above the melt and form a batch blanket that covers the melt surface in a layer, the thickness of which can range, for example, from about 6 to 12 inches.

[0006] From an emissions reduction perspective, all-electric cold crown melting offers several advantages over hydrogen burners, particularly when renewable electricity is available. These advantages include adequate current safety protocols, energy savings, and reduced volatility (and thus reduced waste) of several glass components. These advantages make cold crown melting an attractive technology for reducing carbon emissions. While cold crown melting is not new, it has historically been unsuccessful in producing glass requiring more stringent quality specifications.

[0007] Achieving high throughput and high productivity in cold crown melting, particularly for glass with high quality specifications, requires developments in batch design, equipment, and processes. Therefore, a need exists for improved all-electric cold crown melting technology capable of producing high quality glass at high throughput. Summary of the Invention

[0008] According to an embodiment of the present disclosure, an induction glass melting system for producing glass is provided. The induction glass melting system includes: a melting tank comprising an outer wall extending longitudinally and configured to contain batch material and molten glass for melting, the melting tank comprising a top side and a bottom side opposite the top side; a batch material feeder for feeding batch material into the melting tank at the top side; a glass melt outlet for discharging molten glass from the batch material in the melting tank, the glass melt outlet being configured to discharge the glass melt at the bottom side; and a multi-zone heating system comprising a plurality of induction coils surrounding the perimeter of the melting tank and configured to independently heat a plurality of hot zones longitudinally along the height of the melting tank.

[0009] In some aspects of the embodiment, the multiple heating zones include a batch material zone, which includes a section along the height of the melting furnace for accommodating the batch material added to the melting tank by a batch material feeder. The batch material zone includes a section along the height of the melting furnace, and the interface between the batch material and the molten glass is designed to be located there. The multiple heating zones also include a molten glass zone arranged between the batch material zone and the glassmelt outlet. The molten glass zone includes a section along the height of the melting furnace, which is configured to accommodate molten glass. The multiple heating zones also include a downcomer zone arranged between the molten glass zone and the glassmelt outlet. Therefore, the batch material zone is vertically arranged above the molten glass zone, the downcomer zone is vertically arranged below the molten glass zone, and the molten glass zone is vertically arranged between the batch material zone and the downcomer zone.

[0010] According to other aspects of the embodiments, the outer wall of the melting furnace comprises an induction wall material that is configured to be inductively heated by a multi-zone heating system, and the induction wall material is configured to heat the batch material and / or molten glass in the melting tank. The outer wall may also include an inner lining comprising the induction wall material. In one aspect, the induction wall material comprises platinum. In certain aspects of the embodiments, the melting furnace includes an upper cold zone above the batch material zone, wherein the upper cold zone is not directly heated by heating elements in or surrounding the upper cold zone. The upper cold zone may include a crucible that contains fused silica, quartz, or platinum. The induction melting furnace system can be configured to continuously feed the batch material.

[0011] In other aspects of the embodiment, the system also includes one or more temperature sensors. The temperature sensor may include a thermocouple configured to measure the temperature of at least one of the batch material and the molten glass in the glass furnace. The system may also include a thermocouple sheath at least partially disposed in the melting tank and extending in a direction parallel to the vertical length of the melting tank, the thermocouple sheath comprising a hollow tube sized so that the thermocouple fits within the hollow tube. The thermocouple is configured to move within the hollow tube to read the temperature at different heights in the melting tank. The thermocouple sheath may also be configured to move vertically within the melting tank. The thermocouple sheath comprises aluminum oxide. Other aspects of the embodiment include a hotspot thermocouple disposed at a vertical position in the melting tank corresponding to the highest temperature of the molten glass during the continuous melting process. The hotspot thermocouple may be fixed. Additional temperature sensors may be disposed at at least one of the following: a hotspot, the bottom of the molten glass zone, and the bottom of the downcomer zone where the glass exits the downcomer.

[0012] According to aspects of the embodiment, a batch material feeder includes a batch material feed tube comprising an outlet disposed near the top of a melting tank and an opening upstream of the outlet, wherein the opening is configured to allow heat and / or steam emitted from the melting tank to escape from the batch material feed tube before reaching a source of batch material. A passive batch material distributor can be disposed between the batch material feeder and the melting tank, wherein the passive batch material distributor is configured to evenly distribute the batch material exiting the batch material feeder over a horizontal cross-section of the melting tank. The passive batch material distributor is removably attached to the top of the melting tank. The passive batch material distributor includes an upper support and a lower baffle segment, wherein the upper support has a width wider than the inner diameter of the top side of the melting tank and the lower baffle segment has a width narrower than the inner diameter of the top side of the melting tank, such that the upper support is located on the top of the melting tank and the lower baffle segment is suspended at least partially down into the melting tank. The passive batch material distributor is configured to freely swing about a pivot point where the upper support meets the top side of the melting tank, and the passive batch material distributor is configured to freely swing when struck by batch material dropped from the passive batch material distributor into the melting tank and thereby distribute the batch material across a horizontal cross-section of the melting tank. In an embodiment, the passive batch material distributor comprises a metal sheet and may comprise platinum. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of a cold crown induction glass melter system according to an embodiment of the present disclosure.

[0014] Figure 2 is a schematic diagram of a cold crown induction glass melter system equipped with in-situ measurement according to an embodiment of the present disclosure.

[0015] Figure 3 is a close-up view of the top of a cold crown induction melter system equipped with a batch material distribution mechanism, according to an embodiment.

[0016] Figure 4 is a schematic diagram of an example cold crown induction glass melter system according to an embodiment of the present disclosure.

[0017] Figure 5 is a graph of temperature measurements over time using various temperature sensors according to an example embodiment. DETAILED DESCRIPTION

[0018] Various embodiments of the present disclosure are described in detail below with reference to the accompanying drawings (if any). Reference to various embodiments does not limit the scope of the invention, which is limited only by the scope of the appended claims. In addition, any examples listed in this specification are not limiting and merely illustrate some of the many possible embodiments of the claimed invention.

[0019] Embodiments of the present disclosure relate to systems and methods for cold crown melting of glass. Aspects of the embodiments include an all-electric cold crown melting system that utilizes an induction coil design wrapped around a vertical melter, wherein batch material is added uniformly from above the melt. Aspects of the embodiments include a continuous cold crown melting system and process, wherein glass can be melted continuously by feeding batch material at the same rate as the glass exits the melter's downcomer. Additionally, embodiments of the present disclosure include melting tank designs with better spatial temperature control and improved in-situ measurement capabilities.

[0020] As used herein, "batch material" or "batch material" refers to a material whose constituent elements, when melted together, form the desired glass composition. When melted, the batch material in the melter is transformed into a "glassmelt," "melt," or "molten glass." For a vertical design, batch material is fed from the top and positioned on the top of the molten glass, and the molten glass then falls through the downcomer or outlet of the melter, after which the glass cools and hardens. When positioned on top of the molten glass, the batch material can be referred to as forming a "batch blanket" covering the molten glass. The batch blanket can help reduce heat losses from radiation from the molten glass surface through the top of the melter. The crown space above the batch material is not heated, making it referred to as a "cold crown," which also results in energy savings compared to hot crown melting.

[0021] Embodiments of the present disclosure include new chilled crown tank system designs and methods of using the same, including process development methods, that have significant advantages for process control and measurement. For example, chilled crown induction tanks are capable of repeated cooling and heating, unlike refractory materials that can crack due to thermal cycling. In addition, embodiments of the present disclosure can be used for glasses that are not compatible with ceramic refractory materials. These aspects (e.g., the ability to rapidly cycle the system and perform detailed measurements) make embodiments of the present disclosure highly useful for R&D and / or process development of new and existing glass compositions, and for better understanding batch reactions and the resulting glass quality. Embodiments of the present disclosure are not limited to use with specific glass compositions, and any glass compositions referred to herein are illustrative or for example purposes only. In fact, the advantages of the embodiments herein enable the chilled crown system to be rapidly cycled open and closed to melt a variety of different glass compositions without damaging the melter. While these advantages are clear for process development and R&D purposes, embodiments of the present disclosure can also be used for large-scale glass production.

[0022] In an embodiment, the cold crown melting tank and the glass transfer downcomer are made of or lined with an inductive material and are heated by induction. For example, in some embodiments, the cold crown melting tank and the glass transfer downcomer are made of platinum or contain a platinum lining, but other materials that can be heated by induction can also be used. In aspects of the embodiment, the upper cold section can be made of fused silica, quartz or platinum. The above materials are listed for illustrative purposes only and are not intended to limit the embodiments of the present disclosure. Based on the present disclosure, a person skilled in the art will be able to select suitable materials that meet the requirements of the embodiments described herein.

[0023] Embodiments include continuous melting systems in which batch material is continuously fed from the top and the glass is heated from the sides and below. An advantage of a full platinum or platinum-lined design for the melting tank and downcomer is the ability to add an additional heating zone in the upper batch melting section for additional thermal control of the batch reaction. This additional heating zone is advantageous because some batch materials have a long temperature range over which they form liquids and can result in the formation of sintered batch bridges in the batch blanket (without the additional heating zone in the upper batch melting section providing additional thermal control). The downcomer includes another heating zone (with separate thermal control) and a thermocouple at the outlet. The downcomer can be fed to rollers or other suitable conveying means to draw the exiting glass. With multiple heating zones, the system is able to precisely control the temperature gradients or temperature zones required in different parts of the glass melting process. For example, the control of the top heating zone in the region of the batch material or batch blanket (and possibly including the batch-melt interface) can be independent of the heating of the glass melt below the batch-melt interface. Batch materials that do not necessarily conduct heat well require a lot of energy to heat and melt. Even with high energy input, the batch material temperature rises slowly. However, applying the same high energy input to the melt below the batch blanket can have an adverse effect on the glass structure and composition, and the viscosity is too low. On the other hand, the lower temperature zone below the melt and in the downcomer area can be used to reduce the temperature of the molten glass to increase the viscosity of the glass and control the output.

[0024] See also Figure 1, shows an induction glass melting system 100 for producing glass. The system 100 includes a melting tank 102 including an outer wall 103 extending vertically and configured to contain batch material 112 for melting and molten glass or glass melt. The melting tank 102 has a top side 104 including an opening 105 and a bottom side 106 opposite the top side 104. The bottom side 106 can include a downcomer 128 that controls the descent of the glass melt and when it exits the melting tank 102 at an outlet 107 in the bottom side 106. To further help guide and / or draw the glass out of the outlet 107, a ramp, guide, or roller 129 can be used for the glass 116 exiting the outlet 107. The system 100 also includes a batch material feeder 110 for feeding batch material 112 from a batch material source 114 to the melting tank 102 at the top side 104. The system also includes a multi-zone heating system having different zones 122a, 122b, 122c along the height H of the melting tank 102, capable of controlling the heating of each zone. The multi-zone heating system includes a plurality of induction coils 120a, 120b, 120c around the perimeter of the melting tank and configured to independently heat the plurality of heating zones 122a, 122b, 122c vertically along the height H of the melting tank. In the present disclosure, "independently" means that the energy output of each coil and / or the temperature in each zone can be separately controlled, which can include, for example, controlling the power of the coils and the duration of the induction heating.

[0025] The plurality of heating zones include a batch material zone 122a comprising a vertical section along the height H of the melting furnace 102 for receiving the batch material 112 that has been added to the melting tank 102 via the batch material feeder 110. The batch material zone 122a may also include a batch-melt interface 143 (see Figure 2), which is where the batch material in the melting tank 102 meets the glass melt. The plurality of heating zones also includes a molten glass zone 122b, which includes a vertical section along the height H of the melting furnace 102 between the batch material melt zone 122a and the glass melt outlet 107, which is where the molten glass is designed to be during the melting operation. The plurality of heating zones may also include a downcomer zone 122c disposed between the molten glass zone 122b and the glass melt outlet 107. In other words, in the vertical orientation of the glass melt system 100, the batch material zone 122a is at the top closest to the inlet of the batch material 122; the molten glass zone 122b is midway between the batch material zone 122a and the downcomer zone 122c; and the downcomer zone 122c is at the bottom closest to the outlet 107. Each of the plurality of heating zones 122a, 122b, 122c can be individually heated using separate power inputs from each of the induction coils 120a, 120b, 120c. Separate control of the heating in the batch material zone 122a enables the user to more directly and accurately control the glass transition rate of the batch material 112. By controlling the glass transition rate to match the output rate of the glass 116 leaving the outlet 107, a continuous melting process using a cold crown melter system can be obtained. For example, in an example of an embodiment of the present disclosure, the glass production rate is controlled by temperature control of the downcomer zone 122c and the size of the tube passing through the downcomer 128 to achieve a glass output rate of, for example, 5-10 pounds per hour. Then, by controlling the heating of the batch material zone 122a, the glass transition rate can be matched to approximately 5-10 pounds per hour, resulting in a continuous induction melting process using a cold crown melting system. In order to achieve continuous feeding of the batch material 112 to the melting tank 102, a feeding mechanism (e.g., a screw feeder or auger) can be used to push or pull the batch material 112 from the batch source 114 to the melting tank 102. The temperature control of the batch material zone 122a also enables rapid melting of the batch material and escape control of evolved gases.

[0026] In aspects of the embodiment, the melting tank 102 is equipped with a cold crucible 126 on the top side. The cold crucible 126 is not directly heated by any surrounding induction coils and those form a cold zone 124 in the melting tank. The cold crucible 126 can serve to help funnel the batch material 112 into the melting tank 102 while helping to limit the generation of dust when the batch material 112 is fed into the melting tank 102. The cold crucible can be made of many suitable materials, but some examples include fused silica, quartz, and platinum. In embodiments, the cold crucible can be located on top of the opening of the melting tank 102, or can extend partially into the opening. Additional insulation can be used around the perimeter of the cold crucible to reduce heat loss.

[0027] To induction heat the plurality of hot zones 122a, 122b, 122c by the induction coils 120a, 120b, 120c, the downcomer 128 and the wall 103 of the melting tank 102 may be fabricated from an induction material that heats up in response to the electromagnetic field generated by the induction coils. In some examples discussed herein, this material may be platinum, but other suitable materials are also contemplated. In embodiments, the downcomer 128 and the wall 103 of the melting tank 102 need not be entirely fabricated from an induction material, but may simply have an inner lining of induction material, or components having some induction material may be sufficient to generate the necessary heat to the melt. In embodiments, the melting tank 102 utilizes an induction (e.g., platinum) lining on the inside of a refractory casing.

[0028] See also Figure 1 and 3 , batch material 112 is fed into the melting tank 102 with the aid of a batch material feed tube 110 which brings the batch material 112 from a batch material source 114 to an opening 105 in the top side 104 of the melting tank 102. In an embodiment, a screw feeder or other means of moving the batch material (not shown) may be used in conjunction with the batch material feed tube 110. Without a means of evenly distributing the batch material as it enters the top side 104 of the melting tank 102, the batch material may accumulate unevenly. Existing methods of evenly distributing batch material may include complex moving batch material feed mechanisms, such as motorized mechanisms that move the batch material feed in a circular or other pattern across the top of the melting tank. However, in accordance with embodiments of the present disclosure, a new batch material distribution mechanism may be used that does not require these complex and expensive motorized mechanisms. See Figure 3 Aspects of embodiments of the present disclosure include a passive batch material distributor 150 disposed on the top side 104 of the melt tank 102, positioned between the batch material feeder 110 and the batch material blanket in the melt tank (e.g., Figure 2The passive batch material distributor 150 is arranged so that the batch material 112 exiting the batch material feeder 110 is evenly distributed across the width or horizontal cross-section of the melting tank to achieve a uniform blanket of batch material on top of the melt. In an embodiment, the passive batch material distributor 150 includes an upper support 152 and a lower baffle section 154. The upper support 152 has a width that is wider than the top of the melting tank 102 or the width of the cold crucible 126 on top of the melting tank so that the upper support 152 can span the opening in the top side of the system, and the lower baffle section 154, which has a width less than the width of the opening, can freely hang into the opening. In an embodiment, the lower baffle section 154 has a length such that the bottom of the lower baffle section only partially extends into the cold crucible 126. However, in embodiments, the passive batch material distributor 150 may also be long enough so that the lower baffle section 154 extends partially into the melting tank 102. The exact dimensions of the passive batch material distributor 150 may depend on the target location of the batch material blanket along the melting tank height H. In one illustrative example, a system according to embodiments of the present disclosure may use a one-foot high quartz tube as a cold crucible located on top of the melting tank, and the bottom of the passive batch material distributor 150 may be designed to be approximately one foot above the batch material pile.

[0029] The passive batch material distributor 150 is "passive" because it does not require any motor or other means of applying external force to achieve uniform batch material distribution, other than the force F of the batch material 112 itself hitting the passive batch material distributor 150. The impact of the batch material 112 on the passive batch material distributor 150 causes the passive batch material distributor 150 to oscillate, as shown in FIG. Figure 3 , and such that the batch material 112 is evenly distributed. Without the constraints of complex motorization or other mechanisms, the passive batch material distributor 150 can be located on top of the melter in a removable manner without any permanent attachments. In the absence of permanent attachments, it is simple to remove the passive batch material distributor 150 if additional accessibility to the top side opening is desired. Embodiments may also include a manner of attaching the passive batch material distributor 150 (permanently or removably) to the top side opening in a manner that allows the bottom portion to swing. In aspects of the embodiment, the passive batch material distributor 150 can be constructed from a flat plate having rectangular features, such as Figure 3 However, the embodiment is not limited to Figure 3The passive batch material distributor 150 may include curved and / or rounded corners or other geometric designs, as well as plates or screens with openings to allow some of the batch material 112 to pass through the passive batch material distributor 150. In some exemplary embodiments, the passive batch material distributor 150 is made of metal (e.g., platinum). In aspects of the embodiment, the opening at the end of the batch material feeder 110 can be sized and shaped to provide additional control over the distribution of the batch material 112 entering the melting tank 102.

[0030] Because the batch material feeder 110 may include a tube that angles downward toward the opening 105 of the melting tank 102, the hot air and steam may move upward within the tube, where it may ultimately be directed to the batch material source 114. This may cause issues with the temperature of the batch material and condensation control. To alleviate this issue, embodiments of the present disclosure include a batch material feeder 110 having an opening 160 that is provided upstream but before the batch material source 114, such that the hot air and steam escape the batch material feeder 110 through the opening 160 before reaching the batch material, thereby preventing temperature and condensation control issues.

[0031] According to an embodiment of the present disclosure, an induction melting furnace system is designed to perform one or more in-situ measurements during the melting process to improve process control. Figure 2, embodiments include a thermocouple 131 extending downwardly along the length of the melting tank 102. Thermocouple 131 is movable at least vertically, allowing temperature measurements to be taken throughout the height of the system. In one aspect of the embodiment, thermocouple 131 is placed within a thermocouple sheath 130, which may be a hollow tube with a hollow center dimensioned to allow movement of the thermocouple within the sheath. In one aspect of the embodiment, thermocouple 131 and / or thermocouple sheath 130 are positioned along the centerline or central longitudinal axis 132 of the melting tank 102. Sheath 130 may be made of any material capable of withstanding the temperatures of the melter while allowing the thermocouple to take temperature readings. For example, in some embodiments, the sheath may be made of alumina. In one embodiment, an additional hotspot thermocouple 136 is positioned at the hotspot 134 of the molten glass 144 to continuously monitor the high temperature there. The hotspot corresponds to the highest temperature of the molten glass during the continuous melting process. A bottom thermocouple 137 can be placed at the bottom of the melting tank 102 where the molten glass enters the downcomer 128. Any type of heating sensor capable of adequately measuring the temperature in these environments can be used. In addition, embodiments can include optical pyrometers, such as a first pyrometer 138 below the hot spot and a second pyrometer 139 at the bottom of the melting tank 102. As an additional aspect of the embodiment, a contact thermocouple 140 can be used to directly measure the temperature of the glass 116 exiting the outlet 107.

[0032] According to embodiments of the present disclosure, a continuous cold crown induction melter can be used without a fining vessel or agitator in the glass melt. The melt moves directly from the melting zone into a downcomer.

[0033] Example

[0034] To test an induction cold crown melter according to an embodiment of the present disclosure, a prototype was built and tested with various glass compositions. Figure 4 As shown schematically. Induction heating platinum crucibles and downcomers are selected to achieve rapid heating and cooling of the equipment for daytime operation. The system has a 10-inch high quartz cylinder as a cold crucible, which is located above and extends 3.5 inches into the platinum lining below. Below the quartz crucible is a platinum lining and downcomer in a refractory sleeve for melting the cullet / batch and transferring the glass. The geometry of the downcomer can be adjusted to achieve matching between the overflow rate and the melting rate. For example, downcomers with a diameter of 0.55 inch to 1 inch were used in the experiment. In some experiments, a 0.55 inch diameter was suitable for melting and overflow rates of 5-10 pounds per hour. The downcomer is 20.5 inches long and is heated by induction heating as described above.

[0035] An integrated temperature measurement setup was used to track process variables. The earliest temperature measurement in the process was at the top of the batch blanket, which was tracked by an IR camera and by an optical pyrometer. The temperature of the batch blanket and glass was measured using a thermocouple inserted vertically into the center of the crucible, as shown in Figure 1. Figure 4 As shown in Figure 1, the thermocouple sheath in the melting crucible houses thermocouples in a removable alumina sheath. These thermocouples continuously measure the temperature at two different depths within the crucible. Furthermore, thermocouples are raised and lowered in the alumina sheath to collect thermal profiles as a function of depth in the batch blanket and glass. A contact thermocouple is also added at the top of the downcomer to measure the glass transfer temperature, which helps understand the viscosity changes as it is transferred from the crucible through the downcomer.

[0036] Before starting continuous flow, the amount of time required for the batch material to melt the conversion is measured to determine whether the melting rate is fast enough to provide stable continuous flow. At the beginning of the experiment, the platinum crucible is filled with molten glass to the required batch material / melt interface position. This interface is initially set to the top of the induction coil, but then moves down 3 inches into the platinum crucible to provide additional heating for the side of the batch material blanket. The bottom 3 inches of the quartz crucible are wrapped with insulation material. The batch material is weighed and manually added to the top of the melt surface. Add enough batch material to produce a 2-inch batch material pile height. For a system of this size, the typical weight of this amount of batch material is 2.5 pounds. Once the batch material pile has been established, photos and thermal images of the melt top surface are taken, thereby archiving the changes in surface appearance. These images are analyzed to quantify the reduction of the batch material area over time. If the batch material melts too slowly, the crucible temperature is increased until the batch material melts at a rate of about 5 pounds per hour. After the melting crucible temperature curve has been established, batch material is continuously added to the crucible at the desired rate by either manual or screw feeder, and the glass begins to flow from the downcomer. The batch material feed rate is calculated using a weight gauge on the batch material feeding system. The batch material blanket position and thickness are also measured by inserting a quartz rod into the batch material blanket and recording the height of the batch material blanket and the batch material / glass interface. The amount of batch material adhering to the quartz rod is then measured with reference to the quartz crucible lip to track its change over time. The batch material surface temperature is measured regularly using a handheld optical pyrometer (reflectance coefficient set to 0.8). These measurements are taken approximately every 30 minutes at four equidistant points around the edge of the crucible surface and at the center. The temperature inside the batch material blanket and the glass is measured using an internal thermocouple, as described above. In addition to continuously collecting centerline thermocouple data, the centerline curve is recorded at each set point change and every hour to achieve temperature quantification as a function of the depth through the crucible. A pyrometer is used to monitor the temperature of the outside of the platinum liner at its hottest position and the downcomer. The temperature of the glass leaving the end of the downcomer is measured by a thermocouple.Every 5 minutes, the instantaneous flow rate is calculated by the weight of the glass strip collected in the bucket below the forming rollers.

[0037] This setup was used to produce high-quality glass ribbons with various glass compositions. The conversion of batch material to glass was controlled by appropriately selecting temperature, temperature gradient, feed rate, and pull rate, effectively controlling the continuous process. The resulting glass was found to be of good quality and addressed the issues of retaining additives in the glass composition and preventing these additives from forming solid defects in the glass. Solid defects were rated in the resulting glass.

[0038] Figure 5 Temperature measurements taken over time at the crucible hotspot, centerline, crucible, downcomer, and glass delivery or exit are shown. The centerline thermocouple was raised toward the batch and then lowered to periodically measure the temperature as a function of vertical position, as shown by the slightly vertical thermal profile. Overall, the temperature is very stable. This is provided as an example of an experimental run for illustrative purposes. Figure 5 , to demonstrate the ability of embodiments of the present disclosure to perform in situ measurements.

[0039] The experimental examples showed that a continuous cold crown melter according to embodiments of the present disclosure is capable of delivering a controlled and managed process.

[0040] Schematic implementation method

[0041] The following is a description of various aspects of the implementation of the disclosed subject matter. Each aspect may include one or more of the various features, characteristics, or advantages of the disclosed subject matter. The implementation is intended to illustrate some aspects of the disclosed subject matter and should not be considered a comprehensive or exclusive description of all possible implementations.

[0042] Aspect 1 pertains to an induction glass melting system for producing glass, comprising: a melting tank comprising an outer wall extending vertically and configured to accommodate batch material for melting and molten glass, the melting tank comprising a top side and a bottom side opposite to the top side; a batch material feeder for feeding batch material into the melting tank at the top side; a glass melt outlet for discharging glass melt obtained from melting the batch material in the melting tank, the glass melt outlet being configured to discharge the glass melt at the bottom side; and a multi-zone heating system comprising a plurality of induction coils surrounding the perimeter of the melting tank and configured to independently heat a plurality of hot zones along the height of the melting tank.

[0043] Aspect 2 is the induction glass melting system of aspect 1, wherein the plurality of heating zones comprises batch material zones.

[0044] Aspect 3 is the induction glass melting system of aspect 2, wherein the batch material zone comprises a section along the height of the melting furnace configured to receive batch material added to the melting tank via the batch material feeder.

[0045] Aspect 4 is the induction glass melting system of aspect 2 or aspect 3, wherein the batch material zone includes a section along the height of the melting furnace, and the interface between the batch material and the molten glass is designed to be arranged at the section.

[0046] Aspect 5 is the induction glass melting system of any of aspects 2-4, wherein the plurality of heating zones includes a molten glass zone disposed between the batch material zone and the glass melt outlet.

[0047] Aspect 6 is the induction glass melting system of aspect 5, wherein the molten glass zone comprises a section along the height of the melting furnace configured to contain the molten glass.

[0048] Aspect 7 is the induction glass melting system of any of Aspect 5 or Aspect 6, wherein the plurality of heating zones includes a downcomer zone disposed between the molten glass zone and the glass melt outlet.

[0049] Aspect 8 belongs to the induction glass melting system of aspect 1, wherein the multiple heating zones include a batch material zone, a molten glass zone and a downcomer zone, wherein the batch material zone is vertically arranged above the molten glass zone, the downcomer zone is vertically arranged below the molten glass zone, and the molten glass zone is vertically arranged between the batch material zone and the downcomer zone.

[0050] Aspect 9 pertains to the induction glass melting system of any of aspects 1-8, wherein the outer wall of the melting furnace comprises an induction wall material configured to be inductively heated via a multi-zone heating system, and the induction wall material is configured to heat the batch material and / or molten glass inside the melting tank.

[0051] Aspect 10 is the induction glass melting system of aspect 9, wherein the outer wall comprises an inner lining comprising an induction wall material.

[0052] Aspect 11 is the induction glass melting system of aspect 9 or 10, wherein the induction wall material comprises platinum.

[0053] Aspect 12 is the induction glass melting system of any of aspects 1-11, wherein the melting furnace includes an upper cooling zone above the batch material zone, wherein the upper cooling zone is not directly heated by heating elements in or surrounding the upper cooling zone.

[0054] Aspect 13 is the induction glass melting system of aspect 12, wherein the upper cooling zone comprises a crucible comprising silicon dioxide, quartz, or platinum.

[0055] Aspect 14 is the induction glass melting system of any of aspects 1-13, wherein the induction melting furnace system is configured to continuously feed the batch material.

[0056] Aspect 15 is the induction glass melting system of any of aspects 1-14, further comprising a thermocouple configured to measure the temperature of at least one of the batch material and the molten glass in the glass furnace.

[0057] Aspect 16 is the induction glass melting system of aspect 15, further comprising a thermocouple sheath at least partially disposed in the melting tank and extending in a direction parallel to a vertical length of the melting tank, the thermocouple sheath comprising a hollow tube sized to fit a thermocouple in the hollow tube.

[0058] Aspect 17 is the induction glass melting system of aspect 16, wherein the thermocouple is configured to move within the hollow tube to take temperature readings at different heights within the melting tank.

[0059] Aspect 18 is the induction glass melting system of aspect 16 or 17, wherein the thermocouple sheath is configured to move vertically in the melting tank.

[0060] Aspect 19 is the induction glass melting system of any of aspects 16-18, wherein the thermocouple sheath comprises alumina.

[0061] Aspect 20 is the induction glass melting system of any of aspects 1-19, further comprising a hot spot thermocouple disposed at a vertical position of the melting tank corresponding to a maximum temperature of the molten glass during the continuous melting process.

[0062] Aspect 21 is the induction glass melting system of aspect 20, wherein the hot spot thermocouple is fixed.

[0063] Aspect 22 is the induction glass melting system of any of aspects 1-21, further comprising one or more temperature sensors.

[0064] Aspect 23 is the induction glass melting system of aspect 22, wherein the one or more temperature sensors are disposed at at least one of: a hot spot, a bottom of a molten glass zone, and a bottom of a downcomer zone where glass exits the downcomer.

[0065] Aspect 24 belongs to the induction glass melting system of any of aspects 1-23, wherein the batch material feeder includes a batch material feed tube, wherein the batch material feed tube includes an outlet arranged near the top of the melting tank and an opening upstream of the outlet, wherein the opening is configured to allow heat and / or steam dissipated by the melting tank to escape from the batch material feed tube before reaching the batch material source.

[0066] Aspect 25 belongs to the induction glass melting system of any item of Aspects 1-24, and also includes a passive batch material distributor arranged between the batch material feeder and the melting tank, wherein the passive batch material distributor is configured so that the batch material leaving the batch material feeder is evenly distributed on the horizontal cross-section of the melting tank.

[0067] Aspect 26 is the induction glass melting system of aspect 25, wherein the passive batch material distributor is removably attached to the top of the melting tank.

[0068] Aspect 27 is the induction glass melting system of aspect 25 or 26, wherein the passive batch material distributor includes an upper support and a lower baffle segment, wherein the upper support has a width wider than the inner diameter of the top side of the melting tank and the lower baffle segment has a width narrower than the inner diameter of the top side of the melting tank, so that the upper support is located on the top of the melting tank and the lower baffle segment is suspended at least partially down into the melting tank.

[0069] Aspect 28 is the induction glass melting system of aspect 27, wherein the passive batch material distributor is configured to freely swing about a pivot point at which the upper support meets the top side of the melting tank, and wherein the passive batch material distributor is configured to freely swing when impacted by batch material dropped from the passive batch material distributor into the melting tank and thereby distribute the batch material across a horizontal cross-section of the melting tank.

[0070] Aspect 29 is the induction glass melting system of any of aspects 25-28, wherein the passive batch material distributor comprises a metal sheet.

[0071] Aspect 30 is the induction glass melting system of aspect 29, wherein the passive batch material distributor comprises platinum.

[0072] definition

[0073] The terms "include", "comprising" or similar terms mean including but not limited to, that is, inclusive rather than exclusive.

[0074] In the embodiments described herein, "about" used to modify, for example, the amount, concentration, volume, processing temperature, processing time, yield, flow rate, pressure, viscosity, and similar values and ranges thereof of an ingredient in a composition, or the size of a component, and similar values and ranges thereof, refers to variations in the numerical amount that may occur, for example, from conventional measurements and handling procedures used to prepare materials, compositions, complexes, concentrates, component parts, articles, or use the formulations; from accidental errors in these procedures; from differences in the manufacture, origin, or purity of the starting materials or ingredients used to perform the methods; and similar factors. The term "about" also includes amounts that vary due to aging of a composition or formulation having a specific initial concentration or mixture, as well as amounts that vary due to mixing or processing of a composition or formulation having a specific initial concentration or mixture.

[0075] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0076] As used herein, unless stated otherwise, the indefinite article "a" or "an" and the corresponding definite article "the" mean at least one, or one or more.

[0077] Abbreviations familiar to those skilled in the art may be used (e.g., "h" or "hr" for hours, "g" or "gm" for grams, "mL" for milliliters, "rt" for room temperature, "nm" for nanometers, and the like).

[0078] The specific and preferred numerical values and ranges disclosed in terms of components, ingredients, additives, dimensions, conditions and the like are for illustration only and do not exclude other defined numerical values or other numerical values within defined ranges. The systems, kits and methods of the present disclosure may include any numerical value or any combination of numerical values, specific numerical values, more specific numerical values and preferred numerical values described herein, including explicit or implicit intermediate values and ranges.

[0079] Unless otherwise expressly stated, it is not intended that any method described herein be construed as requiring that its steps be performed in a specific order. Therefore, when a method claim does not actually recite that its steps follow a certain order or when it does not specifically indicate in any other way in the claims or description that the steps are limited to a specific order, it is not intended to imply any particular order.

[0080] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Because those skilled in the art may conceive of various improvements, combinations, sub-combinations, and variations of the disclosed embodiments that incorporate the spirit and substance of the embodiments, the disclosed embodiments should be considered to include all within the scope of the appended claims and their equivalents.

[0081] The foregoing description of the present disclosure is provided as a disclosure of the present disclosure in its currently known embodiments. Those skilled in the art will recognize that many changes can be made to the embodiments described herein while still achieving the beneficial results of the present invention. It is also apparent that a portion of the beneficial results required for the present disclosure can be achieved by selecting some features of the present disclosure without utilizing other features. Therefore, those skilled in the art will recognize that many changes and modifications to the present disclosure are possible, and in some cases may even be desirable, and are part of the present disclosure. Therefore, the following description is provided as an illustration of the principles of the present disclosure and does not constitute a limitation of the present disclosure.

[0082] It will be understood by those skilled in the art that the exemplary embodiments described herein may have various modifications without departing from the spirit and scope of the present disclosure. Therefore, the description is not intended to be, and should not be construed as, limited to the examples given, but should have the full breadth of protection provided by the appended claims and their equivalents. In addition, some features herein may be used while other features are not used accordingly. Therefore, the description of the foregoing examples or illustrative embodiments is provided to illustrate the principles of the present disclosure and does not constitute a limitation thereof, and may include modifications and substitutions to the present disclosure.

[0083] In the foregoing description, like reference numerals designate similar or corresponding parts throughout the several views of the accompanying drawings. It will also be understood that, unless otherwise indicated, terms such as "top," "bottom," "outward," "inward," and the like are words of convenience and are not intended to limit the terms. Furthermore, whenever a group is described as comprising at least one element of a group of elements and combinations thereof, it should be understood that the group may comprise, consist essentially of, or consist of any number of the listed elements, either individually or in combination with one another.

[0084] Similarly, whenever a group is described as consisting of at least one element of a group of elements or a combination thereof, it should be understood that the group can consist of any number of these listed elements in the form of individual elements or in combination with each other. Unless otherwise stated, the numerical ranges recited include both the upper and lower limits of the range. Unless otherwise stated, the indefinite articles "a" and "an" and the corresponding definite article "the" used herein mean "at least one", or "one or more".

[0085] Although this specification may contain many specific instances, they should not be construed as limitations on its scope, but rather as descriptions of features for specific, particular embodiments. Certain features described in the context of separate embodiments of this specification may also be combined and implemented in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments independently or in any appropriate subcombination. Moreover, although the above features are described as functioning in certain combinations and may even be initially claimed as such, one or more features in a claimed combination may in some cases be removed from that combination, and claimed combinations may be directed to subcombinations or variations of subcombinations.

[0086] Similarly, although operations are described in a particular order in the figures or drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve the desired results. In certain circumstances, multitasking and parallel operations may be advantageous.

[0087] Herein, ranges may be expressed as beginning from "about" another particular value and / or ending to "about" another particular value. When expressing such a range, examples include beginning from a particular value and / or ending to another particular value. Similarly, when the antecedent "about" is used to indicate that a value is approximate, it will be understood that the specific value constitutes another aspect. It will also be understood that the endpoints of each range are significant both in relation to the other endpoint and independently of the other endpoint.

[0088] It is also noted that descriptions herein of components of the present disclosure being "configured to" or "adapted to" function in a particular manner. In this regard, such a component is "configured to" or "adapted to" in order to specifically exhibit a particular property, or to function in a particular manner, wherein such descriptions are structural descriptions, rather than descriptions of the intended application. More specifically, the manner in which a component is "configured to" or "adapted to" as described herein refers to the existing physical conditions of the component and, therefore, can be viewed as a limiting description of the structural features of the component.

[0089] While preferred embodiments have been described herein, it should be understood that the embodiments described are merely illustrative and that the scope of the invention is limited only by the appended claims and the full range of equivalents, numerous variations, and improvements that would naturally occur to those skilled in the art upon reading the invention.

Claims

1. An induction glass melting system for producing glass, comprising: a melting tank comprising an outer wall extending vertically and configured to contain batch material for melting and molten glass, the melting tank comprising a top side and a bottom side opposite the top side; a batch material feeder for feeding batch material into the melting tank at the top side; a glass melt outlet for discharging glass melt obtained from melting the batch material in the melting tank, the glass melt outlet being configured to discharge the glass melt at a bottom side; as well as A multi-zone heating system includes a plurality of induction coils around the perimeter of a melting tank and is configured to independently heat a plurality of heating zones vertically along the height of the melting tank.

2. The induction glass melting system of claim 1, wherein: The plurality of heating zones includes a batch material zone.

3. The induction melting furnace system of claim 2, wherein: The batch material zone includes a section along the height of the melting furnace configured to contain batch material added to the melting tank via a batch material feeder.

4. The induction melting furnace system of claim 2, wherein: The batch material zone includes the section along the height of the melting furnace where the interface between the batch material and the molten glass is designed to be disposed.

5. The induction melting furnace system of claim 2, wherein: The plurality of heating zones includes a molten glass zone disposed between a batch material zone and a glass melt outlet.

6. The induction melting furnace system of claim 5, wherein: The molten glass zone includes a section along the height of the melting furnace that is configured to contain molten glass.

7. The induction melting furnace system of claim 5, wherein: The plurality of heating zones includes a downcomer zone disposed between a molten glass zone and a glassmelt outlet.

8. The induction melting furnace system of claim 1, wherein: The plurality of heating zones include a batch material zone, a molten glass zone, and a downcomer zone, The batch material zone is vertically arranged above the molten glass zone, the downcomer zone is vertically arranged below the molten glass zone, and the molten glass zone is vertically arranged between the batch material zone and the downcomer zone.

9. The induction melting furnace system of claim 1, wherein: The outer wall of the melting furnace includes an inductive wall material configured to be inductively heated via the multi-zone heating system, and the inductive wall material is configured to heat the batch material and / or molten glass inside the melting tank.

10. The induction melting furnace according to claim 9, wherein: The outer wall includes an inner lining comprising an inductive wall material.

11. The induction melting furnace system of claim 9, wherein: The sensing wall material comprises platinum.

12. The induction melting furnace system of claim 1, wherein: The melting furnace includes an upper cooling zone above the batch material zone, wherein the upper cooling zone is not directly heated by heating elements in or surrounding the upper cooling zone.

13. The induction melting furnace system of claim 12, wherein: The upper cold zone includes a crucible comprising silicon dioxide, quartz, or platinum.

14. The induction melting furnace system of claim 1, wherein: The induction melting furnace system is configured to continuously feed batch material.

15. The induction melting furnace system of claim 1, further comprising a thermocouple configured to measure a temperature of at least one of the batch material and the molten glass in the glass furnace.

16. The induction melting furnace system of claim 15, further comprising a thermocouple sheath at least partially disposed within the melting tank and extending in a direction parallel to a vertical length of the melting tank, the thermocouple sheath comprising a hollow tube sized to fit a thermocouple within the hollow tube.

17. The induction melting furnace system of claim 16, wherein: The thermocouple was configured to move within the hollow tube to take temperature readings at various heights within the melting tank.

18. The induction melting furnace system of claim 16, wherein: The thermocouple sheath is configured to move vertically in the melting tank.

19. The induction melting furnace system of claim 16, wherein: Thermocouple sheaths consist of alumina.

20. The induction melting furnace system of claim 1, further comprising a hot spot thermocouple disposed in the melting tank at a vertical position corresponding to a maximum temperature of the molten glass during the continuous melting process.

21. The induction melting furnace system of claim 20, wherein: The hot spot thermocouple is fixed.

22. The induction melting furnace system of claim 1, further comprising one or more temperature sensors.

23. The induction melting furnace system of claim 22, wherein: The one or more temperature sensors are disposed at at least one of the following locations: a hot spot, a bottom of a molten glass zone, and a bottom of a downcomer zone where the glass exits the downcomer.

24. The induction melting furnace system of claim 1, wherein: The batch material feeder includes a batch material feed tube including an outlet disposed near a top of the melting tank and an opening upstream of the outlet, wherein the opening is configured to allow heat and / or steam emitted by the melting tank to escape from the batch material feed tube before reaching a source of batch material.

25. The induction melting furnace system of claim 1, further comprising a passive batch material distributor disposed between the batch material feeder and the melting tank, wherein The passive batch material distributor is configured such that the batch material exiting the batch material feeder is evenly distributed across a horizontal cross-section of the melt tank.

26. The induction melting furnace system of claim 25, wherein: A passive batch material distributor is removably attached to the top of the melt tank.

27. The induction melting furnace system of claim 25, wherein: The passive batch material distributor includes an upper support and a lower baffle segment, wherein the upper support has a width wider than the inner diameter of the top side of the melting tank and the lower baffle segment has a width narrower than the inner diameter of the top side of the melting tank, so that the upper support is located on the top of the melting tank and the lower baffle segment is suspended at least partially down into the melting tank.

28. The induction melting furnace system of claim 27, wherein: The passive batch material distributor is configured to freely swing about a pivot point where the upper support meets the top side of the melting tank, and Therein, the passive batch material distributor is configured to swing freely when struck by batch material dropped from the passive batch material distributor into the melting tank and thereby distribute the batch material over a horizontal cross-section of the melting tank.

29. The induction melting furnace system of claim 25, wherein: Passive batch material distributors include metal sheets.

30. The induction melting furnace system of claim 29, wherein: The passive batch material distributor comprises platinum.

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