Molten glass level measuring system and method

Abstract

A molten glass level measuring system, device, and method includes a molten glass level measuring chamber in fluid communication with a conduit or vessel configured to flow molten glass therethrough and a non-contact molten glass level measuring probe configured to measure a level of molten glass in the conduit, vessel, or chamber by determining a distance between the probe and a free surface of the molten glass.

Description

MOLTEN GLASS LEVEL MEASURING SYSTEM AND METHODCross Reference to Related Application

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 566446 filed on March 18, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.Field

[0002] The present disclosure relates generally to molten glass level measuring systems and methods and particularly to non-contact molten glass level measuring systems and methods.Background

[0003] In the production of glass articles, such as glass sheets for display applications, including televisions and hand-held devices, such as telephones and tablets, molten glass is transported through a glass melting system. The glass melting system typically includes vessels or conduits comprising a precious metal or precious metal alloy, wherein molten glass is transported through the vessels or conduits. While processing molten glass through this system, it is desirable to maintain precise and accurate glass level control, which, among other things, helps improve process efficiency and yield. In addition, it is desirable to protect the molten glass from atmospheres or materials that may introduce defects therein. Accordingly, it would be desirable to precisely and accurately measure the level of molten glass in a glass melting system while minimizing or avoiding interaction or contact between the molten glass and such atmospheres or materials.SUMMARY

[0004] Embodiments disclosed herein include a molten glass level measuring system. The molten glass level measuring system includes a conduit or vessel configured to flow molten glass therethrough. The molten glass level measuring system also includes a molten glass level measuring chamber in fluid communication with the conduit or vessel. In addition, the molten glass level measuring system includes a non-contact molten glass level measuringprobe configured to measure a level of molten glass in the conduit, vessel, or chamber by determining a distance between the probe and a free surface of the molten glass.

[0005] Embodiments disclosed herein also include a molten glass level measuring device. The molten glass level measuring device includes a molten glass level measuring chamber in fluid communication with a conduit or vessel configured to flow a molten glass therethrough. The molten glass level measuring device also includes a non-contact molten glass level measuring probe configured to measure a level of molten glass in the conduit, vessel, or chamber by determining a distance between the probe and a free surface of the molten glass.

[0006] Embodiments disclosed herein additionally include a method of measuring a level of molten glass flowing through a conduit or vessel of a glass melting system. The method includes operating a non-contact molten glass level measuring probe to determine a distance between the probe and a free surface of the molten glass, wherein a molten glass level measuring chamber is in fluid communication with the conduit or vessel and extends between the conduit or vessel and the non-contact molten glass measuring probe.

[0007] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosed embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0008] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the claimed embodiments. The accompanying drawings are included to provide further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic view of an example fusion down draw glass making apparatus and process;

[0010] FIG. 2 is a schematic side cutaway view of an example molten glass level measuring system and device in accordance with embodiments disclosed herein;

[0011] FIG. 3 is a schematic side cutaway view of an example molten glass level measuring system and device in accordance with embodiments disclosed herein;

[0012] FIGS. 4A and 4B are side cutaways views of example adapters in accordance with embodiments disclosed herein;

[0013] FIG. 5 is a schematic side cutaway view of an example molten glass level measuring system and device including a waveguide and an adapter in accordance with embodiments disclosed herein;

[0014] FIG. 6 is a schematic side cutaway view of an example molten glass level measuring system and device including a waveguide and an adapter in accordance with embodiments disclosed herein;

[0015] FIG. 7 shows charts of waveguide-based radio frequency (RF) inputs and outputs of an example molten glass level measuring system and device in accordance with embodiments disclosed herein;

[0016] FIG. 8 shows an echo curve chart and a schematic side cutaway view of a corresponding example molten glass level measuring system and device in accordance with embodiments disclosed herein;

[0017] FIG. 9 shows an echo curve chart and a schematic side cutaway view of a corresponding example molten glass level measuring system and device in accordance with embodiments disclosed herein; and

[0018] FIG. 10 shows an echo curve and schematic side cutaway view of an example molten glass level measuring configuration in accordance with embodiments disclosed herein.DETAILED DESCRIPTION

[0019] Reference will now be made in detail to the present preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0020] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0021] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0022] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0023] As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0024] As used herein, the term “molten glass” refers to a glass or glass ceramic composition that is at or above its liquidous temperature (the temperature above which no crystalline phase can coexist in equilibrium with the glass).

[0025] As used herein, the term “free surface of the molten glass” refers to an area where molten glass contacts an atmosphere above the molten glass.

[0026] As used herein the term “conduit” refers to a conduit or vessel of a glass manufacturing apparatus that is configured to flow molten glass therethrough. Non-limiting exemplary conduits include melting vessel 14, mixing vessel 36, fining vessel 34, delivery vessel 40, and connecting conduits.

[0027] As used herein, the term “connecting conduit” refers to a conduit used to connect components of a glass manufacturing apparatus and configured to flow molten glasstherethrough. Non-limiting exemplary connecting conduits disclosed herein include first connecting conduit 32, second connecting conduit 38, and third connecting conduit 46.

[0028] As used herein, the term “non-contact molten glass level measuring probe” refers to a device or apparatus that measures a distance between the device or apparatus and a free surface of the molten glass without any direct contact between the device or apparatus and the molten glass.

[0029] Shown in FIG. 1 is an exemplary glass manufacturing apparatus 10. In some examples, the glass manufacturing apparatus 10 can comprise a glass melting furnace 12 that can include a melting vessel 14. In addition to melting vessel 14, glass melting furnace 12 includes one or more additional components, such as heating elements (as will be described in more detail herein) that heat raw materials and convert the raw materials into molten glass. In further examples, glass melting furnace 12 may include thermal management devices (e.g., insulation components) that reduce heat lost from a vicinity of the melting vessel. In still further examples, glass melting furnace 12 may include electronic devices and / or electromechanical devices that facilitate melting of the raw materials into a glass melt. Still further, glass melting furnace 12 may include support structures (e.g., support chassis, support member, etc.) or other components.

[0030] Glass melting vessel 14 is typically comprised of refractory material, such as a refractory ceramic material, for example a refractory ceramic material comprising alumina, silica, or zirconia. In some examples glass melting vessel 14 may be constructed from refractory ceramic bricks. Specific embodiments of glass melting vessel 14 will be described in more detail below.

[0031] In some examples, the glass melting furnace may be incorporated as a component of a glass manufacturing apparatus to fabricate a glass substrate, for example a glass ribbon of a continuous length. In some examples, the glass melting furnace of the disclosure may be incorporated as a component of a glass manufacturing apparatus comprising a slot draw apparatus, a float bath apparatus, a down-draw apparatus such as a fusion process, an up- draw apparatus, a press-rolling apparatus, a tube drawing apparatus or any other glass manufacturing apparatus that would benefit from the aspects disclosed herein. By way of example, FIG. 1 schematically illustrates glass melting furnace 12 as a component of a fusion down-draw glass manufacturing apparatus 10 for fusion drawing a glass ribbon for subsequent processing into individual glass sheets. Glass melting furnace may also include a submerged combustion melting furnace.

[0032] The glass manufacturing apparatus 10 (e.g., fusion down-draw apparatus 10) can optionally include an upstream glass manufacturing apparatus 16 that is positioned upstream relative to glass melting vessel 14. In some examples, a portion of, or the entire upstream glass manufacturing apparatus 16, may be incorporated as part of the glass melting furnace 12.

[0033] As shown in the illustrated example, the upstream glass manufacturing apparatus 16 can include a storage bin 18, a raw material delivery device 20 and a motor 22 connected to the raw material delivery device. Storage bin 18 may be configured to store a quantity of raw batch materials 24 that can be fed into melting vessel 14 of glass melting furnace 12, as indicated by arrow 26. Raw batch materials 24 typically comprise one or more glass forming metal oxides and one or more modifying agents. In some examples, raw material delivery device 20 can be powered by motor 22 such that raw material delivery device 20 delivers a predetermined amount of raw batch materials 24 from the storage bin 18 to melting vessel 14. In further examples, motor 22 can power raw material delivery device 20 to introduce raw batch materials 24 at a controlled rate based on a level of molten glass sensed downstream from melting vessel 14. Raw batch materials 24 within melting vessel 14 can thereafter be heated to form molten glass 28.

[0034] Glass manufacturing apparatus 10 can also optionally include a downstream glass manufacturing apparatus 30 positioned downstream relative to glass melting furnace 12. In some examples, a portion of downstream glass manufacturing apparatus 30 may be incorporated as part of glass melting furnace 12. In some instances, first connecting conduit 32 discussed below, or other portions of the downstream glass manufacturing apparatus 30, may be incorporated as part of glass melting furnace 12. Elements of the downstream glass manufacturing apparatus, including first connecting conduit 32, may be formed from a precious metal. Suitable precious metals include platinum group metals selected from the group of metals consisting of platinum, iridium, rhodium, osmium, ruthenium and palladium, or alloys thereof. For example, downstream components of the glass manufacturing apparatus may be formed from a platinum -rhodium alloy including from about 100% to about 60% by weight platinum and about 0% to about 40% by weight rhodium. However, other suitable metals can include molybdenum, rhenium, tantalum, titanium, tungsten and alloys thereof. Oxide Dispersion Strengthened (ODS) precious metal alloys are also possible.

[0035] Downstream glass manufacturing apparatus 30 can include a first conditioning (i.e., processing) vessel, such as fining vessel 34, located downstream from melting vessel 14 and coupled to melting vessel 14 by way of the above-referenced first connecting conduit 32. Insome examples, molten glass 28 may be gravity fed from melting vessel 14 to fining vessel 34 by way of first connecting conduit 32. For instance, gravity may cause molten glass 28 to pass through an interior pathway of first connecting conduit 32 from melting vessel 14 to fining vessel 34. It should be understood, however, that other conditioning vessels may be positioned downstream of melting vessel 14, for example between melting vessel 14 and fining vessel 34. In some embodiments, a conditioning vessel may be employed between the melting vessel and the fining vessel wherein molten glass from a primary melting vessel is further heated to continue the melting process or cooled to a temperature lower than the temperature of the molten glass in the melting vessel before entering the fining vessel.

[0036] Bubbles may be removed from molten glass 28 within fining vessel 34 by various techniques. For example, raw batch materials 24 may include multivalent compounds (i.e., fining agents) such as tin oxide that, when heated, undergo a chemical reduction reaction and release oxygen. Other suitable fining agents include without limitation arsenic, antimony, iron and cerium. Fining vessel 34 is heated to a temperature greater than the melting vessel temperature, thereby heating the molten glass and the fining agent. Oxygen bubbles produced by the temperature-induced chemical reduction of the fining agent(s) rise through the molten glass within the fining vessel, wherein gases in the molten glass produced in the melting furnace can diffuse or coalesce into the oxygen bubbles produced by the fining agent. The enlarged gas bubbles can then rise to a free surface of the molten glass in the fining vessel and thereafter be vented out of the fining vessel. The oxygen bubbles can further induce mechanical mixing of the molten glass in the fining vessel.

[0037] Downstream glass manufacturing apparatus 30 can further include another conditioning vessel such as a mixing vessel 36 for mixing the molten glass. Mixing vessel 36 may be located downstream from the fining vessel 34. Mixing vessel 36 can be used to provide a homogenous glass melt composition, thereby reducing cords of chemical or thermal inhomogeneity that may otherwise exist within the fined molten glass exiting the fining vessel. As shown, fining vessel 34 may be coupled to mixing vessel 36 by way of a second connecting conduit 38. In some examples, molten glass 28 may be gravity fed from the fining vessel 34 to mixing vessel 36 by way of second connecting conduit 38. For instance, gravity may cause molten glass 28 to pass through an interior pathway of second connecting conduit 38 from fining vessel 34 to mixing vessel 36. It should be noted that while mixing vessel 36 is shown downstream of fining vessel 34, mixing vessel 36 may be positioned upstream from fining vessel 34. In some embodiments, downstream glass manufacturing apparatus 30 may include multiple mixing vessels, for example a mixing vessel upstreamfrom fining vessel 34 and a mixing vessel downstream from fining vessel 34. These multiple mixing vessels may be of the same design, or they may be of different designs.

[0038] Downstream glass manufacturing apparatus 30 can further include another conditioning vessel such as delivery vessel 40 that may be located downstream from mixing vessel 36. Delivery vessel 40 may condition molten glass 28 to be fed into a downstream forming device. For instance, delivery vessel 40 can act as an accumulator and / or flow controller to adjust and / or provide a consistent flow of molten glass 28 to forming body 42 by way of exit conduit 44. As shown, mixing vessel 36 may be coupled to delivery vessel 40 by way of third connecting conduit 46. In some examples, molten glass 28 may be gravity fed from mixing vessel 36 to delivery vessel 40 by way of third connecting conduit 46. For instance, gravity may drive molten glass 28 through an interior pathway of third connecting conduit 46 from mixing vessel 36 to delivery vessel 40.

[0039] Downstream glass manufacturing apparatus 30 can further include forming apparatus 48 comprising the above -referenced forming body 42 and inlet conduit 50. Exit conduit 44 can be positioned to deliver molten glass 28 from delivery vessel 40 to inlet conduit 50 of forming apparatus 48. For example, exit conduit 44 may be nested within and spaced apart from an inner surface of inlet conduit 50, thereby providing a free surface of molten glass positioned between the outer surface of exit conduit 44 and the inner surface of inlet conduit 50. Forming body 42 in a fusion down draw glass making apparatus can comprise a trough 52 positioned in an upper surface of the forming body and converging forming surfaces 54 that converge in a draw direction along a bottom edge 56 of the forming body. Molten glass delivered to the forming body trough via delivery vessel 40, exit conduit 44 and inlet conduit 50 overflows side walls of the trough and descends along the converging forming surfaces 54 as separate flows of molten glass. The separate flows of molten glass join below and along bottom edge 56 to produce a single ribbon of glass 58 that is drawn in a draw or flow direction 60 from bottom edge 56 by applying tension to the glass ribbon, such as by gravity, edge rolls 72 and pulling rolls 82, to control the dimensions of the glass ribbon as the glass cools and a viscosity of the glass increases. Accordingly, glass ribbon 58 goes through a visco-elastic transition and acquires mechanical properties that give the glass ribbon 58 stable dimensional characteristics. Glass ribbon 58 may, in some embodiments, be separated into individual glass sheets 62 by a glass separation apparatus 100 in an elastic region of the glass ribbon. A robot 64 may then transfer the individual glass sheets 62 to a conveyor system using gripping tool 65, whereupon the individual glass sheets may be further processed.

[0040] FIG. 2 shows a schematic side cutaway view of an example molten glass level measuring system 400 and device 300 in accordance with embodiments disclosed herein. Molten glass level measuring system 400 and device 300 includes a molten glass level measuring chamber 110 in fluid communication with second connecting conduit 38. Molten glass level measuring chamber 110 includes a flared region 112 and is capped with a sealing layer 116. Molten glass level measuring chamber 110 also includes a gas inlet (GI) and a gas outlet (GO) so as to be configured to flow a venting fluid, such as a venting gas, therethrough. Venting gas, can for example, comprise at least one of nitrogen, oxygen, argon, hydrogen, helium, and / or argon.

[0041] Molten glass level measuring system 400 and device 300 also includes a noncontact molten glass level measuring probe 200. Molten glass level measuring probe 200 is configured to measure a level of molten glass in second connecting conduit 38 or molten glass level measuring chamber 110 by determining a distance between the probe 200 and a free surface (FS) of the molten glass. A thermally insulative material 118 is positioned between the molten glass level measuring chamber 110 and the non-contact molten glass level measuring probe 200.

[0042] In certain exemplary embodiments, molten glass level measuring chamber 110 has a generally circular cross section although other cross sections such as elliptical or polygonal are also possible. In certain exemplary embodiments, molten glass level measuring chamber 110 can comprise the same or similar materials as second connecting conduit 38, such as a metal selected from the group of metals consisting of platinum, iridium, rhodium, osmium, ruthenium and palladium, or alloys thereof. For example, molten glass level measuring chamber 110 may comprise a platinum-rhodium alloy including from about 100% to about 60% by weight platinum and about 0% to about 40% by weight rhodium.

[0043] In certain exemplary embodiments, molten glass level measuring probe 200 comprises a waveguide-based sensing mechanism, such as a mechanism that transmits a radio frequency (RF) wave into the molten glass level measuring chamber 110. Accordingly, in certain exemplary embodiments, sealing layer 116 can comprise a material that, on the one hand, can withstand operating temperatures associated with molten glass processing, such as temperatures ranging from about 800°C to about 2000°C, while at the same time are at least partially transparent to waves propagated in the operating wavelengths of the molten glass level measuring probe 200. Such materials may, for example, various ceramic materials, such as slip fused cast silica, sapphire, mullite, quartz, GEM, Al 148, and / or Scimos CZ, which may be sealed to the molten glass level measuring chamber 110 using a hightemperature ceramic based cement. In certain exemplary embodiments, thermally insulative material 118 can also comprise a material that can withstand operating temperatures associated with molten glass processing while at the same time are at least partially transparent to waves propagated in the operating wavelengths of the molten glass level measuring probe 200.

[0044] In certain exemplary embodiments, sealing layer 116 can comprise planar surfaces or protrusions that enable sealing layer 116 to self-align with molten glass level measuring chamber 110. In addition, sealing layer 116 can comprise a single layer or a plurality of stacked layers. Sealing layer 116 can, for example, be secured to molten glass level measuring chamber 110 with a cement adhesive such as Ceramabond 503 or EA139. In addition, sealing layer 116 can be secured to molten glass level measuring chamber 110 by cladding the sealing layer 116 with an extension of the material of the molten glass level measuring chamber 110. Sealing layer 116 may also be inserted through a side slot in the molten glass level measuring chamber 110 or by having threads on an outer circumference of the sealing layer 116 and threading sealing layer 116 into mating threads of the molten glass level measuring chamber 110.

[0045] In certain exemplary embodiments, opposing major surfaces of sealing layer 116 can have minimum reflectivity, which can reduce phase induced noise resulting from 180 degree phase change off of the surface of sealing layer 116 facing molten glass level measuring probe 200. In addition, the signal to noise ratio of RF waves passing through sealing layer can be improved by optimizing thickness and / or dielectric properties of sealing layer 116 to minimize signal loss through the sealing layer material 116 while still maintaining sealing functionality of sealing layer 116 at operating temperatures. Sealing layer 116 may also be positioned such that its opposing major surfaces extend at an oblique angle relative to a propagation direction of a waveguide transmitted between molten glass level measuring probe 200 and free surface of molten glass.

[0046] FIG. 3 shows a schematic side cutaway view of an example molten glass level measuring system 400’ and device 300’ in accordance with embodiments disclosed herein. The molten glass level measuring system 400’ and device 300’ of FIG. 3 is identical to that of FIG. 2 except that it also includes a conduit, which may be fluid cooled, extending between the non-contact molten glass level measuring probe 200 and the molten glass level measuring chamber 110.

[0047] FIG. 5 shows a schematic side cutaway view of an example molten glass level measuring system 400” and device 300” including a waveguide 204 and an adapter 202 inaccordance with embodiments disclosed herein. Waveguide 204 is generally straight and extends between molten glass level measuring chamber 110 and non-contact molten glass level measuring probe 200. Meanwhile, adapter 202 extends between non-contact molten glass level measuring probe 200 and molten glass level measuring chamber 110.

[0048] In certain exemplary embodiments, waveguide 204 has a generally circular cross section (i.e., is generally cylindrical in shape) although other cross sections such as elliptical or polygonal are also possible. In certain exemplary embodiments, the internal diameter of waveguide 204 can be at least about four times the wavelength of a wave, such as an RF wave, propagated through waveguide 204, including an inner diameter of at least about 15 millimeters, at least about 20 millimeters, and at least about 25 millimeters, including from about 15 millimeters to about 50 millimeters, and further including from about 20 millimeters to about 40 millimeters. In certain exemplary embodiments, the internal diameter of waveguide 204 is approximately the same as the internal diameter of molten glass level measuring chamber 110.

[0049] In certain exemplary embodiments, waveguide 204 can comprise a metal, such as stainless steel, platinum, rhodium, quartz, or aluminum (and oxides thereof), for example, SS 304, SS 310, or SS 316. In certain exemplary embodiments, internal surface of waveguide 204 may be polished. In certain exemplary embodiments, the closest distance between waveguide 204 and molten glass level measuring chamber 110 can be less than about 10 millimeters, such as less than about 6 millimeters, including from about 1 millimeter to about 10 millimeters, and further including from about 2 millimeters to about 6 millimeters. In this regard, the thickness of sealing layer 116, which may extend between waveguide 204 and molten glass level measuring chamber 110 may, for example, range from about 1 millimeter to about 10 millimeters, such as from about 2 millimeters to about 6 millimeters. In this regard, sealing layer 116 should be, on the one hand, thick enough to survive thermal and mechanical stresses at operating temperatures while, on the other hand, thin enough to achieve sufficient waveguide-based transmission therethrough. For example, based on expected operating temperatures and dielectric properties of a given sealing layer 116 material at those temperatures, an optimal thickness (or thickness range) for that material may be determined.

[0050] FIG. 6 shows a schematic side cutaway view of an example molten glass level measuring system 400”’ and device 300’” including a waveguide 204 and an adapter 202 in accordance with embodiments disclosed herein. The molten glass level measuring system400”’ and device 300’” of FIG. 6 is identical to that of FIG. 5 except that waveguide 204 is bent at an angle of approximately 90 degrees.

[0051] And while FIGS. 2-3 and 5-6 show a molten glass level measuring system 400, 400’, 400”, or 400’” including a second connecting conduit 38 wherein molten glass level measuring chamber 110 is in fluid communication with second connecting conduit 38, embodiments disclosed herein include molten glass level measuring systems that comprise any conduit or vessel configured to flow molten glass therethrough, including but not limited to, with reference to FIG. 1, melting vessel 14, first connecting conduit 32, fining vessel 34, mixing vessel 36, third connecting conduit 46, delivery vessel 40, exit conduit 44, and / or inlet conduit 50. Accordingly, embodiments disclosed herein include those in which molten glass level measuring chamber 110 is in fluid communication with any of melting vessel 14, first connecting conduit 32, fining vessel 34, second connecting conduit 38, mixing vessel 36, third connecting conduit 46, delivery vessel 40, exit conduit 44, and / or inlet conduit 50.

[0052] FIGS. 4A and 4B show side cutaways views of example adapters 202, 202’ in accordance with embodiments disclosed herein. Adapter 202 or 202’ is positioned between non-contact molten glass level measuring probe 200 and waveguide 204 to, for example, facilitate application of waveguide-based sensing mechanism to determine a distance between non-contact molten glass level measuring probe 200 and free surface of molten glass (e.g., by facilitating propagation of an RF wave between non-contact molten glass level measuring probe 200 and waveguide 204). In this regard, adapter 202 of FIG. 4A can be used in situations where diameter of waveguide 204 is less than diameter of an antenna of noncontact molten glass level measuring probe 200 (wherein top end of adapter 202 as shown in FIG. 4A is proximate to antenna and bottom end of adapter 202 as shown in FIG. 4A is proximate to waveguide 204). Conversely, adapter 202’ of FIG. 4B can be used in situations where diameter of waveguide 204 is greater than or equal to diameter of an antenna of noncontact molten glass level measuring probe 200 (wherein top end of adapter 202’ as shown in FIG. 4B is proximate to antenna and bottom end of adapter 202 as shown in FIG. 4A is proximate to waveguide 204).

[0053] In certain exemplary embodiments, adapter 202 has a minimum internal diameter of about three times the wavelength of a wave, such as an RF wave, propagated through adapter 202, such as a minimum internal diameter of at least about 10 millimeters. In certain exemplary embodiments, adapter 202’ has a maximum internal diameter that is approximately equal to the distance from the non-contact molten glass level measuring probe 200 to the waveguide 204, multiplied by the tangent of half of the angle of the field of viewof the non-contact molten glass level measuring probe 200. Internal reduction angle of adapter 202 or 202’ should be such that adapter 202 or 202’ does not cause undesirable feedback from energy directed from non-contact molten glass level measuring probe 200. Adapter 202 or 202’ may be secured to non-contact molten glass level measuring probe 200 and / or waveguide 204 via threaded connection (e.g., NPSM or NPT threads), welding, or clamp attachment.

[0054] In certain exemplary embodiments, waveguide -based non-contact molten glass level measuring probe 200 transmits a RF wave into molten glass level measuring chamber 110 such that the RF wave comprises a wavelength of less than about 100 millimeters, such as a wavelength of less than about 5 millimeters, including a wavelength of from about 1 millimeter to about 100 millimeters, and further including a wavelength of from about 2 millimeters to about 5 millimeters, and a frequency of greater than about 10 gigahertz (GHz), such as a frequency of greater than about 70 GHz, such as a frequency of from about 10 GHz to about 300 GHz, and further including a frequency of from about 70 GHz to about 90 GHz.

[0055] FIG. 7 shows charts of waveguide-based radio frequency (RF) inputs and outputs of an example molten glass level measuring system and device in accordance with embodiments disclosed herein. Specifically, chart (a) of FIG. 7 shows an RF wave of a sawtooth pattern of varying frequency transmitted from a synthesizer of a frequency modulated continuous wave radio frequency transmitter of a non-contact molten glass level measuring probe. Such pattern can, for example, be provided by a 80 GHz transmitter having a bandwidth of about 4 GHz. The RF wave exits the antennal of the transmitter and encounters objects or materials in the field of view of the non-contact molten glass level measuring probe, including objects or materials in the molten glass measuring system and device. Objects or materials in this field of view can reflect energy from the wave back to the transmitter, which is received by the transmitter and sent to the antenna’s mixer, from which an intermediate frequency signal (IF signal) is derived as a function of both the transmitted frequency and the returning signal frequency, as shown in chart (b) of FIG. 7. The IF signal then undergoes a Fourier transform which provides the distance solution from the sensor to the measured object based on the speed at which the wave travels. If only one object is sensed, the IF signal returns one solution, as shown in chart (c) of FIG. 7. If multiple objects are sensed, the IF signal returns multiple solutions, as shown in chart (d) of FIG. 7. Multiples of the IF signal may be generated as the wave path may occur in intervals, or the Fourier transform may return interval solutions which are sometimes referred to as “ghost” solutions and do not indicate the presence of real objects in space.

[0056] The methodology described with reference to FIG. 7 can also be used when a barrier material, such as a refractory ceramic material of sealing layer 116, is positioned within the field of view of the non-contact molten glass level measuring probe. In such instances, the transmitter can measure the distance to an object or material through another object or material where the thickness and dielectric properties at a given wavelength and temperature of the intermediate object or material are known. Specifically, the molten glass level measuring system and device can be calibrated to account for known objects or materials positioned between the non-contact molten glass level measuring probe and a free surface of the molten glass. Such calibration can effectively offset the degree to which the presence of such know objects or materials would otherwise render a measured distance between the non-contact molten glass level measuring probe and a free surface of the molten glass to be different (e.g., greater) than actuality.

[0057] Embodiments disclosed herein include those in which process control of a glass melting system is improved through utilization of molten glass level measuring systems and devices as disclosed herein. For example, embodiments disclosed herein include those in which at least one parameter of a glass melting system, such as a feed rate of raw materials into the glass melting system is controlled in response to a measured level of molten glass flowing through the conduit or vessel, as measured by molten glass level measuring systems and devices as disclosed herein. For example, the measured level of molten glass can be compared to a predetermined set point and the feed rate of raw materials into the glass melting system can be correspondingly controlled or adjusted based on a comparison of the measured level of molten glass and the set point.

[0058] Examples

[0059] Embodiments disclosed herein will be further described with reference to the following non-limiting examples.

[0060] Example 1 :

[0061] A 1.5 inch inner diameter waveguide 204 is coupled directly to a 1.5 inch diameter NPT end fitting of a VEGA6X 80 GHz transmitter (waveguide-based non-contact molten glass level measuring probe 200) which directs a waveguide -based signal directly into a 1.5 inch inner diameter molten glass level measuring chamber 110. The VEGA6X returns an echo curve depicting the instantaneous measurement to objects detected in the field of view.

[0062] FIG. 8 shows a schematic side cutaway view of this configuration for a molten glass level measuring system 400 and device 400 as well as a graph depicting a corresponding echo curve. The x-axis of the echo curve graph of charts distance and y-axischarts the energy of the received signal at the transceiver of the molten glass level measuring probe 200. Points A, B, C, and D on the graph correspond to points A, B, C, and D of the depicted molten glass level measuring system 400 and device 300. In particular, point A corresponds to the interface of the molten glass level measuring probe 200 and adapter 202. Point B corresponds to the interface of waveguide 204 and sealing layer 116. Point C corresponds to a molten glass level inside molten glass level measuring chamber 110 during normal operation of a glass melting system. Point D corresponds to a molten glass level inside second connecting conduit 38 during a time when a molten glass level is lower than during normal operation (e.g., during a system drainage or leakage event). PactWare software was used to assess the reliability of the measured peaks shown in FIG. 8 using the VEGA6X algorithm. Specifically, each object in the sensor’s field of view returns a signal. That signal is then converted from frequency space into distance space and noted for a relative decibel (dB) returned off the surface. The peak with the greatest dB returned in the region of interest is then trended as an output variable of the sensor.

[0063] Example 2:

[0064] A 0.75 inch inner diameter waveguide 204 is coupled directly to a 1.5 inch diameter NPT end fitting of a VEGA6X 80 GHz transmitter (waveguide-based non-contact molten glass level measuring probe 200) which directs a waveguide -based signal directly into a 1 inch inner diameter molten glass level measuring chamber 110. The VEGA6X returns an echo curve depicting the instantaneous measurement to objects detected in the field of view.

[0065] FIG. 9 shows a schematic side cutaway view of this configuration for a molten glass level measuring system 400 and device 400 as well as a graph depicting a corresponding echo curve. The x-axis of the echo curve graph of charts distance and y-axis charts the energy of the received signal at the transceiver of the molten glass level measuring probe 200. Points E, F, and G on the graph correspond to points E, F, and G of the depicted molten glass level measuring system 400 and device 300. In particular, point E corresponds to the interface of the molten glass level measuring probe 200 and adapter 202. Point F corresponds to the interface of waveguide 204 and sealing layer 116. Point G corresponds to a molten glass level inside molten glass level measuring chamber 110 during normal operation of a glass melting system. PactWare software was used to assess the reliability of the measured peaks shown in FIG. 9 using the VEGA6X algorithm. Specifically, each object in the sensor’s field of view returns a signal. That signal is then converted from frequency space into distance space and noted for a relative dB returned off the surface. The peak withthe greatest dB returned in the region of interest is then trended as an output variable of the sensor.

[0066] Example 3:

[0067] A free space configuration included a sealing layer 116 material positioned between a VEGA6X 80 GHz transmitter (waveguide-based non-contact molten glass level measuring probe 200) and molten glass. The VEGA6X returns an echo curve depicting the instantaneous measurement to objects detected in the field of view.

[0068] FIG. 10 shows a schematic side cutaway view of this configuration as well as a graph depicting a corresponding echo curve. The x-axis of the echo curve graph of charts distance and y-axis charts the energy of the received signal at the transceiver of the molten glass level measuring probe 200. Points H, I, and J on the graph correspond to points H, I, and J of the depicted free space configuration. In particular, point H corresponds to the bottom of the molten glass level measuring probe 200. Point I corresponds to top of the sealing layer 116. Point J corresponds to a molten glass level. PactWare software was used to assess the reliability of the measured peaks shown in FIG. 10 using the VEGA6X algorithm. Specifically, each object in the sensor’s field of view returns a signal. That signal is then converted from frequency space into distance space and noted for a relative dB returned off the surface. The peak with the greatest dB returned in the region of interest is then trended as an output variable of the sensor.

[0069] Embodiments disclosed herein can enable precise and accurate glass level control while protecting molten glass from atmospheres or materials that may introduce defects therein. This can, in turn, improve processing efficiency and yield in the production of glass articles, such as glass articles, including glass articles incorporated into electronic devices, made using processes disclosed herein.

[0070] While the above embodiments have been described with reference to a fusion down draw process, it is to be understood that such embodiments are also applicable to other glass forming processes, such as float processes, slot draw processes, up-draw processes, tube drawing processes, and press-rolling processes.

[0071] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiment of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A molten glass level measuring system comprising: a conduit or vessel configured to flow molten glass therethrough; a molten glass level measuring chamber in fluid communication with the conduit or vessel; a non-contact molten glass level measuring probe configured to measure a level of molten glass in the conduit, vessel, or chamber by determining a distance between the probe and a free surface of the molten glass.

2. The molten glass level measuring system of claim 1, wherein the non-contact molten glass level measuring probe comprises a waveguide-based sensing mechanism.

3. The molten glass level measuring system of claim 1 further comprising a thermally insulative material positioned between the molten glass level measuring chamber and the non-contact molten glass level measuring probe.

4. The molten glass level measuring system of claim 1 further comprising a waveguide positioned between the molten glass level measuring chamber and the non-contact molten glass level measuring probe.

5. The molten glass level measuring system of claim 4 further comprising an adapter positioned between the non-contact molten glass level measuring probe and the waveguide.

6. The molten glass level measuring system of claim 1, wherein the molten glass level measuring chamber is configured to flow a venting fluid therethrough.

7. A molten glass level measuring device comprising:a molten glass level measuring chamber in fluid communication with a conduit or vessel configured to flow a molten glass therethrough; a non-contact molten glass level measuring probe configured to measure a level of molten glass in the conduit, vessel, or chamber by determining a distance between the probe and a free surface of the molten glass.

8. The molten glass level measuring device of claim 7, wherein the non-contact molten glass level measuring probe comprises a waveguide-based sensing mechanism.

9. The molten glass level measuring device of claim 7 further comprising a thermally insulative material positioned between the molten glass level measuring chamber and the non-contact molten glass level measuring probe.

10. The molten glass level measuring device of claim 7 further comprising a waveguide positioned between the molten glass level measuring chamber and the non-contact molten glass level measuring probe.

11. The molten glass level measuring device of claim 10 further comprising an adapter positioned between the non-contact molten glass level measuring probe and the waveguide.

12. The molten glass level measuring device of claim 7, wherein the molten glass level measuring chamber is configured to flow a venting fluid therethrough.

13. A method of measuring a level of molten glass flowing through a conduit or vessel of a glass melting system comprising: operating a non-contact molten glass level measuring probe to determine a distance between the probe and a free surface of the molten glass, wherein a molten glass level measuring chamber is in fluid communicationwith the conduit or vessel and extends between the conduit or vessel and the non-contact molten glass measuring probe.

14. The method of claim 13, wherein the non-contact molten glass level measuring probe comprises a waveguide-based sensing mechanism.

15. The method of claim 14, wherein the waveguide-based sensing mechanism transmits a radio frequency (RF) wave into the molten glass level measuring chamber.

16. The method of claim 15, wherein the RF wave comprises a wavelength of less than about 100 millimeters and a frequency of greater than about 10 gigahertz (GHz).

17. The method of claim 15, wherein the method comprises propagating the RF wave through a waveguide positioned between the molten glass level measuring chamber and the non-contact molten glass level measuring probe.

18. The method of claim 17, wherein the method comprises propagating the RF wave through an adapter positioned between the non-contact molten glass level measuring probe and the waveguide.

19. The method of claim 13, wherein the method comprises flowing a venting fluid through the molten glass level measuring chamber.

20. The method of claim 13, wherein the method comprises controlling a feed rate of raw materials into the glass melting system in response to a measured level of molten glass flowing through the conduit or vessel.

21. A glass article made by the method of claim 13.

22. An electronic device comprising the glass article of claim 21.

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