A method for measuring lithium levels at elevated temperatures.

Abstract

A method and system for measuring the level of molten metal and metal alloys in a crucible is provided. The system includes a crucible, a probe having an electrode positioned at a lowermost probe position, and a processing system configured to receive signals from the electrode and evaluate whether the electrode is in contact with the liquid metal. The system can include multiple probes, each having an electrode positioned at a different height within the crucible. A multi-probe system can inform a user of the system of the level of molten metal located in various sectors within the crucible.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure generally relates to methods and systems for measuring the level of molten metal in a crucible. [Background technology]

[0002] Transistor technology, which began in the 1940s, required the production of semiconductor materials such as germanium and silicon with extremely low concentrations of impurities. Since then, innovative melting and refining techniques have continually advanced.

[0003] One area where current technology has not advanced as rapidly is determining the level of metals and alloys in sealed crucibles. The production of high-purity semiconductor materials often requires the exclusion of oxygen and other contaminating gases from the molten metal process. The ability to determine the level of molten metal in a sealed crucible is often inaccurate or unreliable.

[0004] Some methods for monitoring the level of the contents of a molten crucible include the use of X-rays or gamma rays. The main drawback of these methods is the difficulty in protecting staff from radiation.

[0005] Other methods use multiple thermocouples to measure the temperature at multiple zones within the crucible, which indirectly indicates the level of the liquid. One drawback of these methods is that the interior of the crucible is highly thermally conductive, and heat transfer between different zones can lead to inaccurate measurements.

[0006] Floats have also been used, but mechanical component movement becomes unreliable when the component is immersed in molten metal for extended periods, and cooling and heating cycles can lead to crystal formation on the metal parts, preventing movement.

[0007] Therefore, there remains a need for a method for accurately determining the level of liquid metal in a crucible. Summary of the Invention

[0008] The embodiments described herein generally relate to methods and systems for determining the level of molten metals and metal alloys in a crucible. The metals may be lithium, silicon, germanium, potassium, calcium, magnesium, aluminum, or any other metal, or combinations thereof.

[0009] In one embodiment, a liquid metal level measurement system is provided that includes a crucible operable to contain liquid metal, a probe fixedly coupled to the crucible, and a processing system. The probe includes an electrode disposed at a lowermost probe position. The processing system is configured to receive a signal from the electrode and evaluate whether the electrode is in contact with the liquid metal.

[0010] In another embodiment, a multi-probe liquid metal level measurement system is provided. The system includes a crucible comprising a conductive material, the crucible operable to contain liquid metal. The system further includes at least two probes fixedly coupled to the crucible. Each of the at least two probes includes an electrode at a respective lowermost probe location. The at least two electrodes are disposed within the crucible volume and electrically coupled to the multi-loop circuit. The system further includes a processing system configured to receive a signal from each of the at least two electrodes. The processing system is capable of evaluating whether each of the at least two electrodes is in contact with the liquid metal.

[0011] In yet another embodiment, a method for measuring a level of liquid metal in a crucible is provided. The method includes providing liquid metal to a crucible, the crucible including at least one probe fixedly coupled to the crucible. Each of the at least one probe includes an electrode disposed at a lowermost probe position and within the crucible volume. The method further includes receiving a signal from each of the at least one electrode by a processing system configured to evaluate whether each of the at least one electrode is in contact with the liquid metal. The method further includes using the processing system to determine the liquid metal level relative to the height of each of the at least one electrode within the crucible.

[0012] In order that the above-mentioned features of the present disclosure may be understood in detail, the present disclosure, briefly summarized above, can be further described by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings depict only exemplary embodiments and therefore should not be considered limiting of its scope, as other equally effective embodiments may be recognized. [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows a schematic diagram of a single-probe liquid metal level measurement system according to one or more embodiments of the present disclosure. [Figure 2] 1 shows a schematic diagram of a circuit for a single-probe liquid metal level measurement system in accordance with one or more embodiments of the present disclosure. [Figure 3] 1 illustrates a multi-probe liquid metal level measurement system according to one or more embodiments of the present disclosure. [Figure 4] 1 shows a schematic diagram of a circuit for a dual-probe liquid metal level measurement system in accordance with one or more embodiments of the present disclosure. [Figure 5] 1 illustrates an insulated probe of a liquid metal level measurement system according to one or more embodiments of the present disclosure. [Figure 6]1 shows a process flow diagram summarizing one embodiment of a liquid metal level measurement system according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] For ease of understanding, the same reference numerals have been used, where possible, in the figures to refer to identical common elements, and it is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without the need for further recitation.

[0015] Reference will now be made in detail to various embodiments of the present disclosure, one or more examples of which are illustrated in the figures. In the following description of the figures, like reference numerals refer to like components. Generally, only the differences with respect to individual embodiments will be described. Each example is provided as an illustration of the disclosure and is not meant to limit the disclosure. Furthermore, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield still further embodiments. The description is intended to include such modifications and variations.

[0016] Many of the details, dimensions, angles, and other features shown in the figures are merely illustrative of particular embodiments. Thus, other embodiments may have other details, components, dimensions, angles, and features without departing from the spirit or scope of the present disclosure. Additionally, further embodiments of the present disclosure may be practiced without some of the details described below.

[0017] According to some embodiments, systems and methods are provided for measuring the level of a liquid in a crucible. The terms "liquid metal," "liquid," and "liquid alloy" are used interchangeably. The term refractory refers to a material that can withstand heat. The "level" of the liquid metal in a crucible refers to the distance of the top of the liquid metal from the interior bottom of the crucible.

[0018] Crucibles are used in a variety of industries for melting and transferring metals and other high-melting-point materials. Proper control of the melting and transfer process requires knowledge of the volume of metal contained in the crucible. Due to the high temperatures used to melt the contents of the crucible, it is often difficult to observe or measure the contents of the crucible. Therefore, it would be advantageous to have a method and system for accurate measurement of the level of liquid in a crucible.

[0019] Embodiments of the present disclosure provide systems and methods for measuring the level of a liquid in a crucible. The liquid may be a molten metal, a molten alloy, or other substance that melts at a temperature above about 400°C. In some embodiments, a system for measuring the level of a liquid in a crucible includes a probe fixedly coupled to the crucible and a processing system. In some embodiments, the probe is an insulating probe and includes a probe body made of a heat-resistant material. In some embodiments, the probe body includes a heat-resistant material on the exterior of the probe body. The probe can further include an electrode disposed at a lowermost probe position. The processing system is configured to receive a signal from the electrode to evaluate whether the electrode is in contact with the liquid in the crucible. The crucible can be made of a conductive material, such as stainless steel, and can be grounded.

[0020] An insulating probe can be provided within the crucible volume or can extend into the crucible volume. In some embodiments, at least a portion of the insulating probe can be present within the crucible volume. In some embodiments, the probe includes a conductive component that electrically couples the electrode to the processing system, at least a portion of which is disposed within the probe. The conductive component disposed within the probe can be made of the same material as the electrode or a different material.

[0021] In some embodiments, the crucible, liquid metal, electrodes, and conductive components are part of a circuit included in a liquid metal measurement system. When the metal in the crucible is below the level of the electrodes, i.e., not in contact with the electrodes, the circuit is in an "open" or "complete" state. When the liquid metal in the crucible is at or above the level of the electrodes, the metal is in contact with the electrodes and the circuit is in a "closed" state. The circuit can provide the circuit status to the processing system by sending an "open" or "closed" circuit status to the processing system. When the liquid in the crucible is not in contact with the electrodes, the circuit is in an "open" state, and the processing system can determine that the level of the liquid in the crucible is below the level of the electrodes. When the liquid in the crucible is in contact with the electrodes, the circuit is in a "closed" or "complete" state, and the processing system can determine that the level of the liquid in the crucible is at or above the level of the electrodes.

[0022] In some embodiments, the probe comprises an insulating material on the exterior of the probe body. The insulating material can be any heat-resistant material capable of insulating the interior of the probe from high temperatures, such as temperatures of 400°C or higher. In some embodiments, the insulating material is boron nitride. In some embodiments, the probe comprises an electrode at the lowest probe position. In some embodiments, the probe further comprises an insulating cap disposed between the probe body and the electrode. The insulating cap is configured to prevent the contents of the hot crucible from entering the interior of the probe. In some embodiments, the electrode does not have an insulating material on its exterior. The electrode can be made of stainless steel or other conductive materials known to those skilled in the art. In some aspects, the probe further comprises a hollow interior. A conductive component can be disposed within the probe. The conductive component is configured to electrically couple the electrode to a processing system.

[0023] In some embodiments, the liquid metal level measurement system includes a crucible, at least two insulating probes, and a processing system, each of the at least two insulating probes including an electrode at a respective lowermost probe position, the at least two electrodes being disposed at different heights within the crucible volume. The liquid metal level measurement system further includes a multi-loop circuit, each of the at least two electrodes forming part of a switch within a respective separate circuit loop. The processing system is capable of receiving a signal from each of the at least two electrodes and evaluating whether each of the at least two electrodes is in contact with the liquid metal.

[0024] An embodiment of the present disclosure further provides a method for measuring the level of liquid metal in a crucible. The method includes supplying liquid metal to a crucible and receiving a signal from each electrode by a processing system configured to evaluate whether each electrode is in contact with the liquid metal. The method further includes determining, by the processing system, the level of the liquid metal in the crucible relative to the height or level of the electrodes within the crucible.

[0025] Embodiments of the present disclosure include one or more of the following advantages: The liquid metal level measurement system can be adapted to a sealed crucible to isolate the interior of the crucible from the ambient environment. Thus, the liquid metal level measurement system can be used in systems where there is no direct line of sight to the interior of the crucible. The liquid metal level measurement system can eliminate the use of level sensing thermocouples, which can receive exaggerated temperature signals from the high temperature environment of the crucible. Furthermore, the use of boron nitride insulating material and stainless steel electrodes allows the measurement system disclosed herein to be used at temperatures up to 1,400°C.

[0026] FIG. 1 shows a schematic side view of a liquid metal level measurement system 100 in accordance with one or more embodiments of the present disclosure. The liquid metal level measurement system 100 includes a crucible 102 made of a conductive material, such as stainless steel. The crucible 102 is grounded at a grounding location 140. The system includes a probe 101 including a probe body 104. The probe body 104 may be made of an insulating material or may include insulating material on the probe's exterior. An electrode 108 is provided at a lowermost position of the probe 101. The electrode 108 is located a distance 118 above the bottom of the crucible. In some embodiments, the electrode 108 is made of a conductive material and does not have insulating material on its exterior. The probe 101 further includes a conductive component 106 within the probe body that electrically couples the electrode 108 to a processing system 150. The conductive component 106 may be, for example, a conductive wire, a conductive rod, or a combination thereof. The processing system 150 is grounded at a ground location 152 and includes an energy source. The processing system 150 is configured to receive a signal from the electrode 108 via the conductive component 106. An amplifier (not shown) for amplifying the signal from the electrode 108 may be included upstream of the processing system 150 or may be incorporated into the processing system 150.

[0027] The crucible 102 is configured to contain a liquid metal 130. The top of the liquid metal in the crucible 102 is at a level 109. Because the level 109 of the liquid metal 130 is below the position of the electrode 108 in the crucible 102, the electrode 108 is not in contact with the liquid metal 130. The grounded crucible 102, the liquid metal 130, the electrode 108, the conductive component 106, and the grounded processing system 150 cooperate to form a circuit 200 (FIG. 2). As shown in the circuit diagram of FIG. 2, an amplifier 214 may optionally be included to amplify a signal provided via the circuit 200. The amplifier 214 may be located upstream of the processing system 150 or may be incorporated into the processing system 150. The processing system 150 is configured to receive a signal from the electrode 108 via the conductive component 106 and evaluate whether the electrode is in contact with the liquid metal 130.

[0028] The circuit 200 includes a switch 206, which may be in an “open” state or a “closed” state. The open or closed state of the switch 206 represents the contact state between the liquid metal 130 and the electrode 108 in FIG. 1 . When the level 109 of the liquid metal 130 in the crucible 102 is below the position of the electrode 108 (as in the example shown in FIGS. 1 and 2 ), the liquid metal 130 is not in contact with the electrode 108, and the switch 206 is considered to be in an “open” state. When the level 109 of the liquid metal 130 in the crucible 102 is at the position of the electrode 108 or above the position of the electrode 108, the liquid metal 130 is in contact with the electrode 108, and the switch 206 is considered to be in a “closed” state. When the switch 206 is in a closed state, the grounded crucible 102, liquid metal 130, electrode 108, conductive component 106, and grounded processing system 150 are in electrical communication, completing the circuit 200. 1, the processing system 150 can inform the system operator whether the level 109 of the liquid metal 130 in the crucible 102 is below the position of the electrode 108, or whether the level 109 of the liquid metal 130 is at or above the position of the electrode 108. The "position of the electrode 108" refers to the vertical position of the electrode 108 within the crucible 102.

[0029] 2, a resistor 212 may be optionally included. The resistor 212 may be located upstream of the amplifier 214 (if present) and the processing system 150, or may be incorporated into the processing system 150, and may be downstream of the switch 206.

[0030] 3 shows a schematic side view of a dual-probe liquid metal level measurement system 300 in accordance with one or more embodiments of the present disclosure. The dual-probe liquid metal level measurement system 300 includes a crucible 302 made of a conductive material and grounded at a grounding location 340. The dual-probe liquid metal level measurement system 300 further includes a first probe 301 and a second probe 303. The first probe 301 includes a first probe body 304, which can be made of an insulating material. In some embodiments, the first probe body 304 includes a layer of insulating material on the outside of the probe body. The first probe 301 further includes a first electrode 308 and a first conductive component 306 located within the probe body 304. The first conductive component 306 serves to electrically couple the first electrode 308 to a processing system 350. The processing system 350 is grounded at a grounding location 352 and includes an energy source. The first electrode 308 is positioned a first distance 318 from the bottom of the interior of the crucible 302. The second probe 303 includes a second probe body 312 that may be made of an insulating material. In some embodiments, the second probe body 312 includes a layer of insulating material on the exterior of the probe body. The second probe 303 further includes a second electrode 316 and a second conductive component 314 located within the second probe body 312. The second conductive component 314 serves to electrically couple the second electrode 316 to a processing system 350. The second electrode 316 is positioned a second distance 320 from the bottom of the interior of the crucible 302.

[0031] In some embodiments, the first conductive component 306 and the second conductive component 314 are made of the same material. In some embodiments, the first conductive component 306 and the second conductive component 314 are made of different materials. In some embodiments, the insulating material used to fabricate the first probe body 304 is the same as the insulating material used to fabricate the second probe body 312. In some embodiments, the insulating material used to fabricate the first probe body 304 is different from the insulating material used to fabricate the second probe body 312. In some embodiments, the insulating material provided on the outer surface of the first probe body 304 is the same as the insulating material provided on the outer surface of the second probe body 312. In some embodiments, the insulating material provided on the outer surface of the first probe body 304 is different from the insulating material provided on the outer surface of the second probe body 312.

[0032] The crucible 302 is configured to contain a liquid metal 330. The top of the liquid metal in the crucible 302 is at a liquid metal level 309. The first electrode 308 is at a first distance 318 from the bottom of the crucible 302, the first distance 318 being greater than the liquid metal level 309 of the liquid metal 330 in the crucible 302. The first electrode 308 is above the liquid metal level 309 and therefore not in contact with the liquid metal 330. The second electrode 316 is at a second distance 320 from the bottom of the crucible 302. The second distance 320 is less than the liquid metal level 309 of the liquid metal 330 in the crucible 302. The second electrode 316 is below the liquid metal level 309 and therefore in contact with the liquid metal 330.

[0033] The circuit diagram shown in Figure 4 represents the operating components of Figure 3. The grounded crucible 302, the liquid metal 330, the first electrode 308, the first conductive component 306, the second electrode 316, the second conductive component 314, and the grounded processing system 350 cooperate to form a circuit 400 (Figure 4). As shown in the circuit diagram of Figure 4, an amplifier 414 may optionally be included to amplify signals provided via the circuit 400. The amplifier 414 may be located upstream of the processing system 450 or may be incorporated into the processing system 450. The processing system 450 is configured to receive a signal from the first electrode 308 via the first conductive component 306 and evaluate whether the first electrode 308 is in contact with the liquid metal 330. Further, the processing system 450 is configured to receive a signal from the second electrode 316 via the second conductive component 314 and evaluate whether the second electrode 316 is in contact with the liquid metal 330.

[0034] The circuit 400 further includes a first switch 408 and a second switch 406. As shown in the circuit diagram of FIG. 4, an amplifier 414 may optionally be included to amplify the signal provided through the circuit 400. The amplifier 414 may be located upstream of the processing system 450 or may be incorporated into the processing system 450. As further shown in the circuit diagram of FIG. 4, the circuit may further include a first resistor 412 and a second resistor 416. The first resistor 412 may be located upstream of the amplifier 414 (if present) and the processing system 450 or may be incorporated into the processing system 450, and may be downstream of the first switch 408. The second resistor 416 may be located upstream of the amplifier 414 (if present) and the processing system 450 or may be incorporated into the processing system 450, and may be downstream of the second switch 406.

[0035] The crucible 302 is grounded at a grounding position 340. Within the crucible 302 are a first switch 408 and a second switch 406. The first switch 408 is in an open state, which represents a state in which the liquid metal 330 and the first electrode 308 in FIG. 3 are "not in contact." The second switch 406 is in a closed state, which represents a state in which the liquid metal 330 and the second electrode 316 in FIG. 3 are "in contact." The states of the first switch 408 and the second switch 406 are received and amplified by an amplifier 414 and transmitted to a processing system 450. Thus, the processing system 450 can provide information regarding the level of the liquid metal in the crucible 302 to a system operator. 3 and the corresponding circuit 400 shown in FIG. 4, the processing system 450 receives information indicating that the liquid metal 330 in the crucible 302 is in contact with the second electrode 316 and not in contact with the first electrode 308. Using this information, the processing system 150 can notify a system operator that the level of the liquid metal 330 in the crucible 302 is at or above the vertical position of the second electrode 316 and below the vertical position of the first electrode 308.

[0036] FIG. 5 illustrates a probe 501 according to one or more embodiments of the present disclosure. The probe 501 includes a probe body 504. The probe body 504 may be fabricated from an insulating material. In some embodiments, the probe body 504 includes a layer of insulating material on the exterior of the probe body. The probe 501 further includes an electrode 508 disposed at a lowermost position of the probe 501. A cap 520 is configured to seal the interior of the probe from the liquid metal in the crucible. Within the probe is a conductive component 506. The conductive component 506 is configured to electrically couple the electrode 508 to an amplifier and / or processing system. While in the embodiment illustrated in FIG. 5, the electrode 508 and the conductive component 506 comprise a unitary structure, in some embodiments, the electrode 508 and the conductive component 506 are provided as separate components.

[0037] 6 shows a process flow diagram 600 summarizing one embodiment of a method for measuring liquid metal or alloy in a crucible according to one or more embodiments of the present disclosure. In one embodiment, which may be combined with other embodiments described herein, the method is stored on a computer-readable medium. In one embodiment, which may be combined with other embodiments described herein, the method is performed using a processing system. The method is described with reference to FIGS. 3 and 4.

[0038] In operation 601, liquid metal is provided into a crucible, the crucible having first and second probes fixedly coupled to the interior of the crucible. Each of the first and second probes includes an electrode at its lowest point. The first and second probes are of different lengths such that the first and second electrodes are disposed at different heights within the crucible volume. In operation 602, the processing system determines whether the first electrode disposed at the first height within the crucible volume is in contact with the liquid metal. In operation 603, the processing system determines whether the second electrode disposed at the second height within the crucible volume is in contact with the liquid metal. In operation 604, the processing system uses the information gathered in operations 602 and 603 to determine the level of the liquid metal in the crucible relative to the heights of the first and second electrodes.

[0039] The liquid metal level measurement system disclosed herein can include any number of probes within the crucible volume. For example, the liquid metal level measurement system disclosed herein can include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or even more probes within the crucible volume. Each probe includes an electrode at a lowermost probe position. The probes and their respective electrodes are configured such that each electrode is located at a different height within the crucible volume. A liquid metal level measurement system including an integer "n" number of probes can provide a user of the system with information regarding the level of metal in "n+1" sectors within the crucible. For example, a liquid metal level measurement system including a single probe and a single corresponding electrode (n=1) can determine whether the liquid level is in one of two sectors (n+1=2). A single-probe liquid metal level measurement system can determine whether the liquid level is below the single electrode (i.e., the first sector) or whether the liquid level is at the single electrode or above the single electrode (i.e., the second sector).

[0040] Similarly, a liquid metal level measurement system including two probes (n=2) and two corresponding electrodes (a lower electrode and an upper electrode) can determine whether the liquid level is in one of three (n+1=3) sectors. A dual-probe liquid metal level measurement system can determine whether the liquid level is below the lower electrode (i.e., the first sector). A dual-probe liquid metal level measurement system can determine whether the liquid level is below the upper electrode and at or above the lower electrode (i.e., the second sector). Finally, a dual-probe liquid metal level measurement system can determine whether the liquid level is at or above the third electrode (i.e., the third sector).

[0041] A liquid metal level measurement system including three probes (n=3) and three corresponding electrodes (lower electrode, center electrode, and upper electrode) can determine whether the liquid level is in one of four (n+1=4) sectors. The triple-probe liquid metal level measurement system can determine whether the liquid level is below the lower electrode (i.e., the first sector). The triple-probe liquid metal level measurement system can determine whether the liquid level is below the center electrode and at or above the lower electrode (i.e., the second sector). The triple-probe liquid metal level measurement system can determine whether the liquid level is below the upper electrode and at or above the center electrode (i.e., the third sector). Finally, the triple-probe liquid metal level measurement system can determine whether the liquid level is at or above the upper electrode (i.e., the fourth sector). By using n electrodes, the liquid metal level measurement system can determine whether the liquid level is in one of n+1 sectors within the crucible.

[0042] The liquid metal level measurement systems disclosed herein can include a controller operable to control various aspects of the liquid metal level measurement system. The controller can facilitate control and automation of the level measurement system and can include a central processing unit (CPU), memory, and support circuitry (or I / O). Software instructions and data can be encoded and stored in the memory for instructing the CPU. The controller can communicate with one or more of the components of the level measurement system, for example, via a system bus. A program (or computer instructions) readable by the controller determines which measurements to take. In some embodiments, the program is software readable by the controller that can include code for monitoring the state of the crucible and detecting the state of the electrode. It should be understood that multiple system controllers can be used in the embodiments described herein. The controller can be one of any form of general-purpose computer processor that can be used in an industrial environment to control various crucibles and sub-processors.

[0043] A controller may be provided in or coupled to the various components of the processing system to control their operation. The methods described herein may be stored in the memory of the controller as software routines that may be executed or invoked to control the operation of the level measurement system in the manner described herein.

[0044] The embodiments and all functional operations described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural means disclosed herein and their structural equivalents, or in combinations of these. The embodiments described herein can also be implemented as one or more non-transitory computer program products, i.e., one or more computer programs tangibly embodied in a machine-readable storage device for execution by or control the operation of a data processing device, such as a programmable processor, a computer, or multiple processors or computers.

[0045] The methods described herein may be performed by one or more programmable processors executing one or more computer programs to perform functions by manipulating input data and generating output. The processes and logic flows may also be performed by, and apparatus may be implemented as, special purpose logic circuitry, such as an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

[0046] In summary, some advantages of the present disclosure include the ability to remotely detect the level of liquid metal in a crucible. The crucible may be a sealed crucible with no direct line of sight to the interior of the crucible. A liquid metal level measurement system can be used to detect the level of liquid metal in a sealed crucible with no direct line of sight. The liquid metal level measurement system can include multiple probes to determine whether the liquid level in the crucible is within multiple height sectors within the crucible. The liquid metal level measurement system does not rely on the use of thermocouples, which can receive extraordinary temperature signals from the high-temperature environment of the crucible. Furthermore, the use of boron nitride insulating material and stainless steel electrodes allows the measurement system disclosed herein to be used at temperatures up to 1,400°C. The liquid metal level measurement system can be used to prevent underfilling and overfilling of a crucible.

[0047] When introducing elements of the present disclosure or exemplary aspects or embodiments thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the element.

[0048] The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0049] While the foregoing is directed to several embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, which scope is determined by the following claims.

Claims

1. a crucible operable to contain a liquid metal; a probe fixedly coupled to the crucible, the probe having an electrode disposed at a lowermost probe position; a processing system configured to receive a signal from the electrode and evaluate whether the electrode is in contact with the liquid metal; A liquid metal level measurement system comprising:

2. The liquid metal level measurement system of claim 1 , wherein the probe further comprises a conductive component disposed therein and electrically coupled to the electrode and the processing system.

3. The liquid metal level measurement system of claim 1 , wherein the crucible comprises an electrically conductive material.

4. 10. The liquid metal level measurement system of claim 1, wherein the crucible is grounded.

5. a circuit configured to provide an open / close signal to the processing system; The liquid metal level measurement system of claim 1 further comprising:

6. 6. The liquid metal level measurement system of claim 5, wherein the circuit is configured to send an open circuit condition signal to the processing system when the electrode is not in contact with the liquid metal.

7. 6. The liquid metal level measurement system of claim 5, wherein the circuit is configured to send a closed circuit status signal to the processing system when the electrode is in contact with liquid metal.

8. The liquid metal level measurement system of claim 1 , wherein the probe is made of an insulating material.

9. The liquid metal level measurement system of claim 1 , wherein the probe comprises an insulating material on an exterior of the probe.

10. The liquid metal level measurement system of claim 1 , wherein the electrode comprises stainless steel.

11. a crucible comprising an electrically conductive material and operable to contain a liquid metal; at least two probes fixedly coupled to the crucible, each of the at least two probes having an electrode at a respective lowermost probe position disposed within the crucible volume, the at least two electrodes electrically coupled to a multi-loop circuit; a processing system configured to receive a signal from each of the at least two electrodes and evaluate whether each of the at least two electrodes is in contact with the liquid metal; and A liquid metal level measurement system comprising:

12. 12. The liquid metal level measurement system of claim 11, wherein each of said at least two electrodes is provided at a different height within said crucible volume.

13. 12. The liquid metal level measurement system of claim 11, wherein the crucible is grounded.

14. 12. The liquid metal level measurement system of claim 11, wherein each of the at least two probes further comprises a conductive component disposed therein and electrically coupled to a respective electrode and to the processing system.

15. 12. The liquid metal level measurement system of claim 11, wherein the multi-loop circuit is configured to provide an open / closed circuit loop signal for each circuit loop to the processing system.

16. 16. The liquid metal level measurement system of claim 15, wherein each of the at least two electrodes is configured to function as a switch for a separate circuit loop.

17. 17. The liquid metal level measurement system of claim 16, wherein a circuit loop is configured to send a closed-circuit loop status signal to the processing system when a corresponding electrode is in contact with liquid metal.

18. 17. The liquid metal level measurement system of claim 16, wherein a circuit loop is configured to send an open circuit loop status signal to the processing system when the corresponding electrode is not in contact with the liquid metal.

19. 1. A method for measuring the level of liquid metal in a crucible, comprising: providing a liquid metal to a crucible having at least one insulated probe fixedly coupled to the crucible, each of the at least one probe having an electrode disposed within the crucible volume at a lowermost probe position; receiving a signal from each of the at least one electrode by a processing system configured to evaluate whether each of the at least one electrode is in contact with the liquid metal; determining, by the processing system, a level of liquid metal relative to the height of each of the at least one electrode within the crucible; A method comprising:

20. 20. The method of claim 19, further comprising at least two electrodes, each of the at least two electrodes being disposed at a different height within the crucible.

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