Patent Publication Number: US-2023147586-A1

Title: Multi-purpose pump system for a metal furnace and related methods

Description:
REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 62/981,282, filed on Feb. 25, 2020 and entitled MULTI-PURPOSE PUMP SYSTEM FOR A METAL FURNACE AND RELATED METHODS, the content of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This application relates to metal furnaces, and, more particularly, to pumps for metal furnaces. 
     BACKGROUND 
     A typical metal furnace includes an enclosed main chamber that holds a molten material, such as molten metal, and includes heating elements that produce enough heat to maintain the molten condition. The molten material may be poured into a casting machine to produce a metal ingot. In some cases, a charging well and a separate pump with a pumping well are in fluid communication with the main chamber. The pump typically includes a component that directly contacts the molten material to circulate the molten material. In particular, the pump may draw the molten material from the main chamber of the metal furnace and then force the molten material into the charging well and back into the main chamber of the metal furnace. Metal scrap may be introduced into the molten material in the charging well where the scrap melts and becomes part of the molten material. It is common for the charging well to include an impeller, which rotates in the charging well to promote mixing and submergence of scrap that is introduced into the molten material. A separate dross well may be provided between the charging well and the main chamber, and dross may be collected from the upper surface of the molten material in the dross well before it is recirculated to the main chamber. 
     SUMMARY 
     Embodiments covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various embodiments and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings, and each claim. 
     According to certain embodiments, a pump system for a metal furnace includes a tank and a magnetic stirrer. The tank includes a tank chamber that is configured to receive a fluid, such as a molten material. The tank is positioned above the magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber. The magnetic stirrer includes a rotating permanent magnet, and the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material. 
     According to some embodiments, a pump system for a metal furnace includes a tank that includes a tank chamber, an inlet, and an outlet. The tank chamber is configured to receive a fluid, such as a molten material. The inlet is in fluid communication with the tank chamber and defines a flow path to the tank chamber for molten material entering the tank chamber. The outlet is in fluid communication with the tank chamber and defines a flow path from the tank chamber for molten material exiting the tank chamber. A transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet. 
     According to various embodiments, a pump system for a metal furnace includes a tank and a mixer. The tank includes a tank chamber that is configured to receive a fluid, such as a molten material. The mixer is selectively positionable within and removable from the tank chamber, and the mixer includes a body that includes one or more fins along an edge of the body. 
     According to some embodiments, a pump system for a metal furnace includes a tank and a mixer. The tank includes a tank chamber that is configured to receive a fluid, such as a molten material. The mixer is selectively positionable within and removable from the tank chamber, and the mixer includes a body, the body that defines a supply passageway having at least one opening along a vertical edge of the body. The mixer is configured to selectively supply an injectable material into the tank chamber via the supply passageway and the at least one opening. 
     According to certain embodiments, a mixer for a pump system for a metal furnace includes a body with an edge extending along a length of the body, at least one fin along the edge of the body, and a supply passageway extending at least partially through the body and that includes at least one opening defined in the edge of the body. 
     According to various embodiments, a method includes receiving, from a furnace, molten material in a tank chamber of a tank of a pump system. The method also includes generating a mixing flow in the molten material in the tank chamber. In some examples, generating the mixing flow includes rotating a permanent magnet of a magnetic stirrer of the pump system to generate a moving magnetic field in the molten material in the tank chamber, and controlling the moving magnetic field to induce movement in the molten material. The method may include discharging the molten material from the tank. 
     Various implementations described herein can include additional systems, methods, features, and advantages, which cannot necessarily be expressly disclosed herein but will be apparent to one of ordinary skill in the art upon examination of the following detailed description and accompanying drawings. It is intended that all such system, methods, features, and advantages be included within the present disclosure and protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The specification makes reference to the following appended figures, in which use of like reference numerals in different figures is intended to illustrate like or analogous components. 
         FIG.  1    is a diagram of a metal melting system with a metal furnace and a pump system according to embodiments of the disclosure. 
         FIG.  2    is a perspective view of a pump system for a metal melting system according to embodiments of the disclosure. 
         FIG.  3    is another perspective view of the pump system of  FIG.  2   . 
         FIG.  4    is an exploded assembly view of the pump system of  FIG.  2   . 
         FIG.  5    is a perspective view of a tank of the pump system of  FIG.  2   . 
         FIG.  6    is a sectional view of the tank of the pump system of  FIG.  2   . 
         FIG.  7    is a sectional view of a mixer of a mixing system of the pump system of  FIG.  2   . 
         FIG.  8    is a side view of a tank and magnetic stirrer of a pump system according to embodiments of the disclosure. 
         FIG.  9    is a perspective view of the tank of the pump system of  FIG.  8   . 
         FIG.  10    is a perspective view of a pump system according to embodiments of the disclosure. 
         FIG.  11    is another perspective view of the pump system of  FIG.  10   . 
         FIG.  12    is a schematic view of a sidewell melting furnace with a pump system according to embodiments of the disclosure. 
         FIG.  13    is a schematic view of a dual chamber furnace with a pump system according to embodiments of the disclosure. 
         FIG.  14    is another schematic of the dual chamber furnace with the pump system of  FIG.  13   . 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter of embodiments of the present disclosure is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. Directional references such as “up,” “down,” “top,” “bottom,” “left,” “right,” “front,” and “back,” among others, are intended to refer to the orientation as illustrated and described in the figure (or figures) to which the components and directions are referencing. 
     As used herein, a “transverse dimension” refers to the dimension across the widest portion of the component. It will be appreciated that the transverse dimension may depend on a shape of the component. A diameter of an object is an example of a transverse dimension. As such, while the description below may reference diameters, it will be appreciated that the shape of the tank chamber and/or the components of the pump system is not considered limiting. 
     Described herein are pump systems for a metal furnace and associated methods. In certain aspects, the pump system may be utilized in a melting system for melting various metals, and may be particularly suited for melting systems for melting aluminum. In some examples, the pump system may be utilized with a recycling melting furnace, including but not limited to a sidewell melting furnace or a dual chamber melting furnace. Such recycling melting furnaces may be designed to handle different forms of scrap (e.g., light gauge, medium gauge, and heavy gauge). The pump system described herein may improve mixing and melting of metal scrap by improving the submergence of metal scrap in molten material. The pump system may also improve the mixing of additives (e.g., salt) into the molten material during the melting by improving the submergence of such additives in the molten material. 
     The pump system may include a tank and a magnetic stirrer. The tank includes a tank chamber, and a molten material, such as molten metal, may be retained within and pumped through the tank chamber. The magnetic stirrer includes a rotating permanent magnet, and the tank is positioned above the magnetic stirrer such that a moving magnetic field generated by the rotating permanent magnet induces movement in the molten material in the tank chamber of the tank. 
     The pump system may also include a mixer assembly that includes at least one mixer that is selectively positionable within and removable from the tank chamber for certain processes of the pump system. The mixer has a body with at least one fin along an edge of the mixer that may generate a flow rotation within the molten material when the mixer is lowered into the tank chamber. The mixer may also include a supply passageway that is at least partially defined within the body and that may be used to supply an injectable material, such as salt, into the tank chamber when the mixer is lowered into the tank chamber. In some examples, the mixer may be in a lowered position (or at least partially positioned within the tank chamber) for some processes of the pump system and may be in a raised position (or outside of the tank chamber) for other processes of the pump system. As some non-limiting examples, the mixer may be in the raised position for processes such as dross collection and/or some pumping processes, and the mixer may be in the lowered position for processes such as metal addition and/or salt injection. In other examples, the mixer may be in the raised position and/or the lowered position as desired. 
     The pump system described herein may allow for multiple processes to be performed with the same pump system, thereby providing a more compact system that can be used with metal furnaces and/or more easily retrofit into existing metal melting systems. The pump system may also omit moving parts in the molten material during certain processes (e.g., during certain pumping processes, salt injection, scrap addition, etc.). 
       FIG.  1    illustrates an example of a furnace system  100  that includes a metal furnace  102  and a pump system  104  according to various embodiments. The metal furnace  102  may heat and contain a source of molten material, such as molten metal (e.g., molten aluminum). The metal furnace  102  may be various types of metal furnaces including, but not limited to, a sidewell melting furnace, a dual chamber furnace, etc. Molten metal from the metal furnace  102  may be used to produce a metal ingot through various casting techniques. 
     The pump system  104  includes a tank  106 , a magnetic stirrer  108 , and a mixer assembly  110 . The tank  106  includes a tank chamber  114  that is in fluid communication with the metal furnace  102  by an inlet conduit  116  and an outlet conduit  118  such that molten material may be supplied to the tank  106  via the inlet conduit  116  and removed from the tank  106  via the outlet conduit  118 . In various examples, an inlet  122  of the tank chamber  114  is at a vertical position that is below a vertical position of an outlet  124  of the tank chamber  114  such that molten material is pumped in an upwards direction within the tank chamber  114 . 
     The tank chamber  114  has a chamber wall  126 . In various examples, a transverse dimension, such as a diameter, of the chamber wall  126  proximate to an inlet  122  of the tank chamber  114  is different from the transverse dimension of the chamber wall  126  proximate to an outlet  124  of the tank chamber  114 . In the example of  FIG.  1   , the transverse dimension of the chamber wall  126  proximate to the inlet  122  is less than the transverse dimension of the chamber wall  126  proximate to the outlet  124 . In certain aspects, the tank chamber  114  having at least two different transverse dimensions may guide and/or improve movement of the molten material through the tank chamber  114 . The chamber wall  126  having at least two different transverse dimensions may also shape an upper surface of the molten material within the tank chamber  114  (e.g., to have a conical shape) at certain pumping speeds to for a collection point for dross and facilitate removal of dross. In some examples, at certain pumping speeds, the chamber wall  126  shapes the molten material such that a collection point is formed in a top surface of the molten material within the tank chamber  114  for dross and facilitate removal of dross. The collection point may facilitate removal of dross with a dross removal device (such as, but not limited to, a robotic arm, an Archimedes screw type assembly, etc.). The chamber wall  126  may also provide better scrap submergence within the tank chamber  114  because the chamber wall  126  may generate a vortex in the molten material, which may lead to scrap being submerged within the melt and not on the melt surface. The chamber wall  126  may also promote mixing during mixing processes (e.g., salt injection) because the vortex generated by the chamber wall  126  may submerge the added material (e.g., salt) below the melt surface, which may minimize or reduce salt loss entrapment on the melt surface and lead to lower salt consumption. The chamber wall  126  may also optionally allow for pumping of the molten material without requiring drain plugs near the drain hole due to the improved mixing in the molten material, thereby reducing the safety hazard otherwise associated with drain plugs. While the profile of the chamber wall  126  is illustrated as linear in  FIG.  1   , it need not be in other examples, and the particular profile of the chamber wall  126  should not be considered limiting. The geometry of the chamber wall  126  may be selected to improve flow of the molten metal within the tank chamber  114  and/or to ensure the molten metal climbs up the chamber wall  126  to be discharged out the outlet  124 . 
     The magnetic stirrer  108  includes a permanent magnet  120  that is rotatable about an axis such that the permanent magnet  120  generates a moving magnetic field. In the example of  FIG.  1   , the permanent magnet  120  is rotatable about a vertical axis  130  of the tank chamber  114 , although in other examples the permanent magnet  120  may be rotatable about any axis as desired. While a single permanent magnet  120  is illustrated, in other examples, the magnetic stirrer  108  may include a plurality of permanent magnets  120  that are each rotatable about an axis. In various examples, the tank  106  is supported above the magnetic stirrer  108  such that the moving magnetic field generated by the rotating permanent magnet  120  induces movement in the molten material in the tank chamber  114 , thereby pumping the molten material through the tank chamber  114  along a flow path (represented by arrows  128 ) and recirculating the molten material back to the metal furnace  102 . 
     The mixer assembly  110  includes at least one mixer  112  and is movable (represented by arrow  132 ) between a lowered position and a raised position. In various examples, in the lowered position, the at least one mixer  112  may be positioned at least partially within the tank chamber  114  and/or at least partially within the molten metal within the tank chamber  114 , and, in the raised position, the at least one mixer  112  may be positioned above the molten metal within the tank chamber  114  and/or outside of the tank chamber  114 . In certain cases, the mixer assembly  110  may be in the raised position or the lowered position depending on a process of the pump system  104 . As some non-limiting examples, the mixer assembly  110  may be in the raised position for certain pumping and/or dross collection processes and may be in the lowered position for certain scrap addition or mixing processes (e.g., salt injection). 
     The mixer assembly  110  may include any number of mixers  112  as desired, so while three mixers  112  are illustrated in  FIG.  1   , the number of mixers  112  should not be considered limiting. When a plurality of mixers  112  are included, the mixers  112  may be interconnected through or integrally formed with a common base  134  such that the mixers  112  are movable together between the raised position and the lowered position. In other examples, each mixer  112  may be independently movable relative to another mixer  112  between the raised position and the lowered positions. 
     The mixers  112  may be at various angles relative to the vertical axis  130  of the tank chamber  114 . In various aspects, the angle of the mixers  112  relative to the vertical axis  130  may at least partially control a rotational flow characteristic of the molten material within the tank chamber  114 . In the example of  FIG.  1   , the mixers  112  are substantially parallel to the vertical axis  130 , although they need not be substantially parallel to the vertical axis  130  in other examples. As some non-limiting examples, in other cases, one or more of the mixers  112  may be at an angle of about 15°, about 30°, about 45°, about 60°, etc. relative to the vertical axis  130 . When a plurality of mixers  112  are utilized, the angle of one mixer  112  relative to the vertical axis  130  may be the same as or different from the angle of another mixer  112  relative to the vertical axis  130 . In some cases, the mixers  112  may be fixed at their respective angles relative to the vertical axis  130  however, in other examples, one or more mixers  112  may be adjustable such that the mixers  112  can be positioned at an angle relative to the vertical axis  130  as desired. 
     As discussed in greater detail below with reference to  FIG.  7   , each mixer  112  may have a supply passageway that may be used to add various injectable materials (e.g., salt) into the molten material in the tank chamber  114 . In various examples, the mixers  112  with the supply passageway may allow for the injectable material to be added below the melt surface of the molten material, which may minimize salt loss entrapment on the metal surface and lead to lower salt consumption. Additionally or alternatively, and as also discussed in greater detail below with reference to  FIG.  7   , each mixer  112  may have one or more fins along an edge of the mixer  112  to generate rotational flow within the molten material. In various examples, the mixers  112  in the lowered position may maintain their general position within the tank chamber  114  (e.g., they may be stationary within the tank chamber  114 ). As discussed in greater detail below, molten material flowing within the tank chamber  114  (e.g., by the magnetic stirrer  108 ) may flow around the mixers  112 , and the flow of the molten material around the mixers  112  may generate additional rotational flow within the molten metal. 
       FIGS.  2 - 7    illustrate another example of a pump system  204  according to various embodiments. The pump system  204  is substantially similar to the pump system  104  and includes a tank  206 , a magnetic stirrer  208 , and a mixer assembly  210 . 
     The magnetic stirrer  208  is substantially similar to the magnetic stirrer and includes a rotatable permanent magnet (not visible in the views illustrated). 
     As best illustrated in  FIG.  4   , a refractory material  236  may support the tank  206 , and various covering materials  238  (e.g., steel plates or other suitable material) may enclose the tank  206  and refractory material  236 . As best illustrated in  FIGS.  5  and  6   , the profile of a chamber wall  226  of the tank chamber  214  is different from the profile of the chamber wall  126  of  FIG.  1    and is non-linear between the portion of the chamber wall  226  proximate to an inlet  222  and the portion of the chamber wall  226  proximate to an outlet  224 . Similar to the tank chamber  114 , a transverse dimension of the tank chamber  214  proximate to the inlet  222  is less than the transverse dimension of the tank chamber  214  proximate to the outlet  224 . In various examples, the tank chamber  214  with the reduced transverse dimension proximate to the inlet  222  may promote and/or improve the flow of the molten material through the tank chamber  214  from the inlet  222  to the outlet  224 . As mentioned, the geometry of the chamber wall of the tank chamber  214  may be selected to improve flow of the molten metal within the tank chamber  214  and/or to ensure the molten metal climbs up the chamber wall to be discharged out the outlet. The geometry of the chamber wall of the tank chamber  214  may generate a vortex in the molten material, which may improve scrap submergence inside the melt, improve the flow of molten metal through the tank (e.g., improved pumping), improve mixing of the molten material within the tank chamber (and reducing metal solidification within the tank chamber), and/or improve mixing of scrap and/or other injectable material in the melt. 
     Compared to the tank  106 , the tank  206  also includes a supplemental chamber  240  that is in fluid communication with the outlet  224  of the tank chamber  214  and a supplemental inlet  242  of the tank chamber  214 . In certain optional examples, at least some of the molten material exiting the tank chamber  214  may be diverted to the supplemental chamber  240  and recirculated back into the tank chamber  214  via the supplemental inlet  242 . In other examples, the supplemental chamber  240  may be omitted. 
     As best illustrated in  FIGS.  2 - 4  and  7   , similar to the mixer assembly  110 , the mixer assembly  210  includes three mixers  212 . Each of the mixers  212  includes a body  246  that is optionally supported on a support  252 . In various examples, the body  246  is movable along the support  252  such that the mixer  212  is movable between the lowered position and the raised position, although in other examples, the body  246  is fixed relative to the support  252  (i.e., not movable). In the example illustrated, the body  246  is fixed relative to the support  252 . In other examples, the support  252  may be omitted and various other suitable devices or mechanisms may be utilized to support and/or position the body  246  as desired. The body  246  has a first edge  248  and a second edge  250  opposite from the first edge  248 . The first edge  248  and the second edge  250  may extend along a length of the body  246 . 
     As best illustrated in  FIG.  7   , in various examples, the second edge  250  may include one or more fins  256 . The fins  256  may be integrally formed with the body  246  or may be separate components that are coupled to the body  246  through various suitable mechanisms. In the example of  FIG.  7   , the second edge  250  includes seven fins  256 , although the number of fins  256  should not be considered limiting. Similarly, the shape, profile, or pattern of the fins  256  should not be considered limiting. When the mixer  212  is lowered into the molten material in the tank chamber  214 , the fins  256  may generate turbulence and/or a rotational flow in the molten material, thereby providing increased mixing and/or pumping of the molten metal flowing through the tank chamber  214 . In various aspects, rotational flow generated by the fins  256  may be controlled by controlling one or more of the number of fins  256  on the mixer  212 , the profile or pattern of the fins  256 , the number of mixers  212  with the mixer assembly  210 , the angle of the mixer  212  relative to the vertical axis of the tank chamber  214 , the orientation of the second edge  250  with the fins  256  relative to the vertical axis (e.g., the second edge  250  faces radially inwards, radially outwards, in a clockwise circumferential direction, in a counter-clockwise circumferential direction, etc.), or other features of the mixer assembly  210 . 
     Additionally or alternatively, each mixer  212  may include a supply passageway  258  that extends at least partially through the body  246  and is in fluid communication with one or more openings  260  that are defined by the body  246 . In various examples, the openings  260  may be defined in edges or sides of the body  246  that are not a leading edge or side in the flow of molten material (e.g., in a trailing edge of the body  246 ). In the example of  FIGS.  2 - 7   , the openings  260  are defined in the second edge  250  of the body  246 . The number, shape, location, and profile of the openings  260  and/or the supply passageway  258  should not be considered limiting. For example, in other cases, each opening  260  may have a dedicated supply passageway  258  rather than having a common supply passageway  258  for the openings  260 . The supply passageway  258  may be in fluid communication with an injectable material source  262  such that an injectable material, including but not limited to salt, may be selectively supplied into the molten material via the supply passageway  258  and the openings  260 . In examples with a plurality of mixers  212 , all of the mixers  212  may include the supply passageway  258  and the openings  260  or a subset of the mixers  212  may include the supply passageway  258  and the openings  260 . In some non-limiting examples, the injectable material may be supplied to the molten material when the mixers  212  are in the lowered position. 
     The mixer assembly  210  also includes a dross removal device  244 . The dross removal device  244  may be any suitable device or mechanism for removing dross from the molten material in the tank chamber  214 . In the example of  FIGS.  2 - 7   , the dross removal device  244  is a robotic arm; however, in other examples, the dross removal device  244  may be any other suitable device. A non-limiting example of another dross removal device  244  includes an Archimedes screw type assembly. 
       FIGS.  8  and  9    illustrate another example of a portion of a pump system  804  with a tank  806  and a magnetic stirrer  808 . Although not illustrated, a mixer assembly similar to the mixer assembly  110  or the mixer assembly  210  may be utilized with the pump system  804 . 
     The tank  806  is substantially similar to the tank  206  except that the supplemental chamber  240  is omitted. As best illustrated in  FIG.  9   , similar to the tank  206 , the profile of a chamber wall  826  of a tank chamber  814  of the tank  806  is non-linear between the portion of the chamber wall  826  proximate to an inlet  822  and the portion of the chamber wail  826  proximate to an outlet  824 . Similar to the tank chamber  214  and the tank chamber  114 , a transverse dimension of the tank chamber  814  proximate to the inlet  822  is less than the transverse dimension of the tank chamber  814  proximate to the outlet  824  such that the chamber wall  826  narrows from the top of the tank chamber  814  toward the bottom of the tank chamber  814 . 
     Similar to the pump system  104  and the pump system  204 , the magnetic stirrer  808  of the pump system  804  includes one or more permanent magnets rotatable about an axis, and the magnetic stirrer  808  is positioned below the tank  806  such that a moving magnetic field generated by the rotating permanent magnet induces movement in the molten material in the tank chamber  814  of the tank  806 . 
       FIGS.  10  and  11    illustrate another example of a pump system  1004  with a tank  1006 , magnetic stirrer  1008 , and mixer assembly  1010  (omitted from  FIG.  11   ). The pump system  1004  is in fluid communication with a furnace  1002 . The tank  1006  is similar to the previously mentioned tanks and includes a chamber wall  1026  having a profile that is non-linear between the portion of the chamber wall  1026  proximate to an inlet  1022  and the portion of the chamber wall  1026  proximate to an outlet  1024 . A transverse dimension of the tank chamber  1014  proximate to the inlet  1022  is less than the transverse dimension of the tank chamber  1014  proximate to the outlet  1024  such that the chamber wall  1026  narrows from the top of the tank chamber  1014  toward the bottom of the tank chamber  1014 . Similar to the mixer assembly  110 , the mixer assembly  1010  includes three mixers  1012  and is movable between the raised position and the lowered position such that the mixers  1012  are at least partially within the molten material. 
       FIG.  12    illustrates an example of a pump system  1204  with a sidewell melting furnace  1202  that includes a main furnace chamber  1203 . One or more burners  1207  or other suitable heating elements are provided to produce a molten condition. The pump system  1204  is substantially similar to the previously discussed pump systems and includes a tank  1206  having a chamber wall with a profile that is non-linear between an inlet  1222  and the an outlet  1224 . A transverse dimension of the tank chamber proximate to the inlet  1222  is less than the transverse dimension of the tank chamber proximate to the outlet  1224  such that the chamber wall narrows from the top of the tank chamber toward the bottom of the tank chamber. Although not illustrated in  FIG.  12   , the pump system  1204  also includes a magnetic stirrer and a mixer assembly. A flow of molten material is represented by arrows  1205 , and the flow path may be from the main furnace chamber  1203 , to the tank  1206 , and either back to the main furnace chamber  1203  or for further processing. As illustrated in  FIG.  12   , various materials such as metal scrap (represented by arrow  1211 ) and/or injectable materials (represented by arrow  1209 ) may be added during the melting process. Compared to existing sidewell melting furnaces, the sidewell melting furnace  1202  with the pump system  1204  may promote better submergence of the scrap  1211  because of the vortex generated in the tank  1206 , which may lead to scrap submerged inside the melt and not on the melt surface. Salt or other injectable materials  1209  are similarly better submerged below the melt surface and mixed, which may minimize salt loss entrapment on the melt surface and lead to lower salt consumption. Drain plugs may optionally be omitted because of the improved mixing and pumping of molten material with the tank  1206 . 
       FIGS.  13  and  14    illustrate an example of the pump system  1204  with a dual chamber furnace  1302  that includes a scrap chamber  1313  and a heating chamber  1315 . Metal scrap  1317  (see  FIG.  14   ) may be introduced into the scrap chamber  1313  (in addition to the metal scrap  1211 ). A flow of molten material is represented by arrows  1305 , and the flow path may be from the scrap chamber  1313  to the heating chamber  1315 , to the tank  1206 , and back to the scrap chamber  1313 . Compared to existing dual chamber furnaces, the dual chamber furnace  1302  with the pump system  1204  may promote better submergence of the scrap  1211  and/or other injectable materials  1209 . The dual chamber furnace  1302  may also be more easily cleaned compared to existing dual chamber furnaces because the pump system  1204  may be an open system and components are more easily accessible. 
     Referring back to  FIG.  1   , a method of processing molten material with the pump system  104  is also provided. While reference will be made to the pump system  104 , it will be appreciated that the following description is equally applicable to the pump system  204  and the pump system  804 , or other pump systems, unless expressly noted otherwise. 
     The method may include receiving the molten material from the furnace  102  in the tank chamber  114  of the tank  106 . Receiving the molten material may optionally include drawing the molten material from the furnace  102 , through the inlet conduit  116  and the inlet  122 , and into the tank chamber  114  by rotating the permanent magnet  120  of the magnetic stirrer  108  such that a rotational or mixing flow is generated within the tank chamber  114 . 
     In various examples, the method includes controlling the flow of the molten material through the tank chamber  114  from the inlet  122  to the outlet  124 . In various aspects, controlling the flow of molten material may include, but is not limited to, controlling one or more of a rotational speed of the permanent magnet  120 , an axis of rotation of the permanent magnet, a number of permanent magnets, and/or a profile of the chamber wall  126  of the tank chamber  114 . In some cases, the profile of the chamber wall  126  is controlled such that the transverse dimension of the tank chamber  114  proximate to the inlet  122  is less than the transverse dimension of the tank chamber  114  proximate to the outlet  124 . 
     In some optional examples, the method includes controlling the flow of the molten material by controlling the magnetic stirrer  108  such that a collection point is formed in a top surface of the molten material within the tank chamber  114  for dross and facilitate removal of dross. The method may include using a dross removal device to remove the dross from the molten material before it is pumped out the outlet  124 . 
     In various examples, the method may include lowering one or more mixers  112  of the mixer assembly  110  from the raised position to the lowered position such that the mixers  112  are at least partially within the molten material. In certain aspects, the method includes substantially maintaining a position of the mixers  112  relative to the tank chamber  114  (e.g., the mixers  112  are stationary within the tank chamber  114 ). 
     In certain examples, an edge of a body of each mixer  112  may include one or more fins, and the one or more fins positioned within the molten material may generate turbulence and/or a supplemental mixing flow (in addition to the flow generated by the magnetic stirrer  108 ) within the molten material. Optionally, the method may include controlling the supplemental mixing flow generated by the fins of the mixers  112  by controlling one or more of the number of fins on the mixer  112 , the profile or pattern of the fins, the number of mixers  112  with the mixer assembly  110 , the angle of the mixer  112  relative to the vertical axis  130  of the tank chamber  114 , or the orientation of the edge with the fins  1  relative to the vertical axis  130 , or other features of the mixer assembly  110 . 
     In some examples, the method may include adding scrap material to the molten material in the tank chamber  114  while the mixers  112  are in the lowered position. In various examples, the method may include injecting an injectable material (such as, but not limited to, salt) into the molten material while the mixers  112  are in the lowered position. In certain aspects, injecting the injectable material may include supplying the injectable material to the supply passageway defined in the body of each mixer  112  and directing the injectable material through the supply passageway and out the one or more openings defined in the body of each mixer  112 . In various cases, injecting the injectable material may include controlling, at least one of the type of injectable material injected into the molten material, a flow or supply rate of the injectable material. a number of openings defined in the body of each mixer  112 , or other features of the mixer assembly  110 . In certain aspects, the method may include raising the mixer assembly  110  from the lowered position to the raised position after adding the scrap material and/or after injecting the injectable material. 
     A collection of exemplary embodiments are provided below, including at least some explicitly enumerated as “Illustrations” providing additional description of a variety of example embodiments in accordance with the concepts described herein. These illustrations are not meant to be mutually exclusive, exhaustive, or restrictive; and the disclosure not limited to these example illustrations but rather encompasses all possible modifications and variations within the scope of the issued claims and their equivalents. 
     Illustration 1. A pump system for a metal furnace, the pump system comprising: a tank comprising a tank chamber configured to receive a molten material; and a magnetic stirrer comprising a rotating permanent magnet, wherein the tank is positioned above magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber, and wherein the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material. 
     Illustration 2. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the tank further comprises: an inlet in fluid communication with the tank chamber and defining a flow path to the tank chamber for molten material entering the tank chamber; and an outlet in fluid communication with the tank chamber and defining a flow path from the tank chamber for molten material exiting the tank chamber, wherein a transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet. 
     Illustration 3. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein a vertical position of the inlet is lower than a vertical position of the outlet. 
     Illustration 4. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein a chamber surface of the tank chamber comprises a non-linear curve between the inlet and the outlet. 
     Illustration 5. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the transverse dimension of the tank chamber proximate to the inlet is less than the transverse dimension of the tank chamber proximate to the outlet. 
     Illustration 6. The pump system of any preceding or subsequent illustrations or combination of illustrations, further comprising a mixer selectively positionable within and removable from the tank chamber. 
     Illustration 7. The pump system of any preceding or subsequent illustrations or combination. of illustrations, wherein the mixer comprises a body, and wherein the body comprises one or more fins along an edge of the body. 
     Illustration 8. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the mixer comprises a body, and wherein the body comprises: a supply passageway extending through at least a portion of the body; and at least one opening defined in an edge of the body, wherein the at least one opening is in fluid communication with the supply passageway, and wherein the mixer is configured to selectively supply an injectable material into the tank chamber via the supply passageway and the at least one opening. 
     Illustration 9. The pump system of any preceding or subsequent illustrations or combination of illustrations wherein the edge further comprises one or more fins along the length of the body. 
     Illustration 10. A pump system for a metal furnace, the pump system comprising: a tank comprising: a tank chamber configured to receive a molten material; an inlet in fluid communication with the tank chamber and defining a flow path to the tank chamber for molten material entering the tank chamber; and an outlet in fluid communication with the tank chamber and defining a flow path from the tank chamber for molten material exiting the tank chamber, wherein a transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet. 
     Illustration 11. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein a vertical position of the inlet is lower than a vertical position of the outlet. 
     Illustration 12. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein a vertical position of the inlet is lower than a vertical position of the outlet. 
     Illustration 13. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein a chamber surface of the tank chamber comprises a non-linear curve between the inlet and the outlet. 
     Illustration 14. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the transverse dimension of the tank chamber proximate to the inlet is less than the transverse dimension of the tank chamber proximate to the outlet. 
     Illustration 15. The pump system of any preceding or subsequent illustrations or combination of illustrations, further comprising a magnetic stirrer comprising a rotating permanent magnet, wherein the tank is positioned above magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber. and wherein the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material. 
     Illustration 16. The pump system of any preceding or subsequent illustrations or combination of illustrations, further comprising a mixer selectively positionable within and removable from the tank chamber. 
     Illustration 17. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein. the mixer comprises a body, and wherein the body comprises one or more fins along an edge of the body. 
     Illustration 18. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the mixer comprises a body, and wherein the body comprises: a supply passageway extending through at least a portion of the body; and at least one opening defined in an edge of the body, wherein the at least one opening is in fluid communication with the supply passageway, and wherein the mixer is configured to selectively supply an injectable material into the tank chamber via the supply passageway and the at least one opening. 
     Illustration 19. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the edge further comprises one or more fins along the length of the body. 
     Illustration 20. A pump system for a metal furnace, the pump system comprising: a tank comprising a tank chamber configured to receive a molten material; and a mixer selectively positionable within and removable from the tank chamber, the mixer comprising a body, the body comprising one or more fins along an edge of the body. 
     Illustration 21. The pump system of any preceding or subsequent illustrations or combination of illustrations, further comprising a magnetic stirrer comprising a rotating permanent magnet, wherein the tank is positioned above magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber, and wherein the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material. 
     Illustration 22. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the tank further comprises: an inlet in fluid communication with the tank chamber and defining a flow path to the tank chamber for molten material entering the tank chamber; and an outlet in fluid communication with the tank chamber and defining a flow path from the tank chamber for molten material exiting the tank chamber, wherein a transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet. 
     illustration 23. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the body further comprises: a supply passageway extending through at least a portion of the body; and at least one opening defined in an edge of the body, wherein the at least one opening is in fluid communication with the supply passageway, and wherein the mixer is configured to selectively supply an injectable material into the tank chamber via the supply passageway and the at least one opening. 
     Illustration 24. A pump system for a metal furnace, the pump system comprising: a tank comprising a tank chamber configured to receive a molten material; and a mixer selectively positionable within and removable from the tank chamber, the mixer comprising a body, the body defining a supply passageway having at least one opening along a vertical edge of the body, wherein the mixer is configured to selectively supply an injectable material into the tank chamber via the supply passageway and the at least one opening. 
     Illustration 25. The pump system of any preceding or subsequent illustrations or combination of illustrations, further comprising a magnetic stirrer comprising a rotating, permanent magnet, wherein the tank is positioned above magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber, and wherein the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material. 
     Illustration 26. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the tank further comprises: an inlet in fluid communication with the tank chamber and defining a flow path to the tank chamber for molten material entering the tank chamber; and an outlet in fluid communication with the tank chamber and defining a flow path from the tank chamber for molten material exiting the tank chamber, wherein a transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet. 
     Illustration 27. The pump system of any preceding or subsequent illustrations or combination of illustrations, wherein the vertical edge further comprises one or more fins positioned along a length of the body. 
     Illustration 28. A mixer for a pump system for a metal furnace, the mixer comprising: a body comprising an edge extending along a length of the body; at least one fin along the edge of the body; and a supply passageway extending at least partially through the body and comprising at least one opening defined in the edge of the body. 
     Illustration 29. A method comprising: receiving, from a furnace, molten material in a tank chamber of a tank of a pump system; generating a mixing flow in the molten material in the tank chamber, wherein generating the mixing flow comprises: rotating a permanent magnet of a magnetic stirrer of the pump system to generate a moving magnetic field in the molten material in the tank chamber; and controlling the moving magnetic field to induce movement in the molten material, wherein the tank is positioned above magnetic stirrer such that the magnetic stirrer is outside of the tank chamber; and discharging the molten material from the tank. 
     Illustration 30. The method of any preceding or subsequent illustrations or combination of illustrations, further comprising removing dross from the molten material in the tank chamber while generating the mixing flow in the molten material. 
     Illustration 31. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the mixing flow is a secondary mixing flow, and wherein the method further comprises: generating a primary mixing flow in the molten material by lowering a mixer into the tank chamber and at least partially into the molten material, wherein the mixer comprises a body, the body comprising an edge extending along a length of the mixer, wherein the edge comprises one or more fins. 
     Illustration 32. The method of any preceding or subsequent illustrations or combination of illustrations, further comprising adding scrap material into the tank chamber while generating the primary mixing flow. 
     Illustration 33. The method of any preceding or subsequent illustrations or combination of illustrations, further comprising injecting an injectable material into the molten material while generating the mixing flow by: lowering a mixer into the tank chamber and at least partially into the molten material, wherein the mixer comprises a body, the body comprising a supply passageway extending at least partially through the body and comprising at least one opening defined in an edge of the body; and injecting the injectable material through the supply passage, out the at least one opening, and into the molten material. 
     Illustration 34. The method of any preceding or subsequent illustrations or combination of illustrations, further comprising selecting a geometry of the tank chamber to promote flow of the molten material from the inlet toward the outlet. 
     Illustration 35. The method of any preceding or subsequent illustrations or combination of illustrations, wherein selecting the geometry comprises selecting a transverse dimension of the tank chamber proximate to the inlet that is different from the transverse dimension of the tank chamber proximate to the outlet. 
     Illustration 36. The method of any preceding or subsequent illustrations or combination of illustrations, wherein selecting the geometry comprises selecting a transverse dimension of the tank chamber proximate to the inlet is less than the transverse dimension of the tank chamber proximate to the outlet. 
     The above-described aspects are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the present disclosure. Many variations and modifications can be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure, and all possible claims to individual aspects or combinations of elements or steps are intended to be supported by the present disclosure. Moreover, although specific terms are employed herein, as well as in the claims that follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described embodiments, nor the claims that follow.