Rotating magnet heat induction

Abstract

To efficiently transfer heat energy to a metal strip.SOLUTION: Rotating magnet heaters for metal products, such as aluminum strip, may include permanent magnet rotors positioned above and below a moving metal strip to induce a moving or time-varying magnetic field through the metal strip. The changing magnetic field may induce currents (e.g., eddy currents) in the metal strip, thus heating the metal strip. The magnetic rotor set can include a pair of aligned magnetic rotors on opposite sides of the metal strip that rotate at the same speed. Each magnetic rotor of a set can be positioned equidistant from the metal strip to avoid pulling the metal strip away from the passline. The downstream magnetic rotor set may be used in proximity to the upstream magnetic rotor set to offset the tension induced by the upstream magnetic rotor set.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 400,426, entitled "ROTATING MAGNET HEAT INDUCTION," filed September 27, 2016; U.S. Provisional Patent Application No. 62 / 505,948, entitled "ROTATING MAGNET HEAT INDUCTION," filed May 14, 2017; and U.S. Provisional Patent Application No. 62 / 529,053, entitled "SYSTEMS AND METHODS FOR CURING A COATED METAL STRIP," filed July 6, 2017, the disclosures of which are incorporated herein by reference in their entireties.

[0002] Additionally, this application is incorporated herein by reference in its entirety. U.S. Non-Provisional Patent Application No. 15 / 716,559, filed September 27, 2017, to Antoine Jean Willy Pralong et al., entitled "SYSTEMS AND METHODS FOR NON-CONTACT TENSIONING OF A METAL STRIP," U.S. Non-Provisional Patent Application No. 15 / 716,577, filed September 27, 2017, to David Michael Custers, entitled "PRE-AGING SYSTEMS AND METHODS USING MAGNETIC HEATING," U.S. Non-Provisional Patent Application No. 15 / 716,608, filed September 27, 2017, to David Anthony Gaensbauer et al., entitled "COMPACT CONTINUOUS ANNEALING SOLUTION HEAT TREATMENT," and U.S. Non-Provisional Patent Application No. 15 / 716,608, filed September 27, 2017, to David Anthony Gaensbauer et al., entitled "MAGNETIC LEVITATION HEATING OF METAL WITH CONTROLLED SURFACE No. 15 / 716,692 to David Anthony Gaensbauer et al., entitled "THREADING A HOT COIL ON A MILL QUALITY," filed September 27, 2017; U.S. Non-Provisional Patent Application No. 15 / 716,698 to Andrew James Hobbis et al., entitled "SYSTEMS AND METHODS FOR THREADING A HOT COIL ON A MILL," filed September 27, 2017; and U.S. Non-Provisional Patent Application No. 15 / 716,570 to Julio Malpica et al., entitled "RAPID HEATING OF SHEET METAL BLANKS FOR STAMPING," filed September 27, 2017, the disclosures of which are incorporated herein by reference in their entireties.

[0003] FIELD OF THE DISCLOSURE The present disclosure relates generally to metal processing, and more specifically to heating metal strip, such as non-ferrous metal strip, using rotating magnets. [Background technology]

[0004] In metal processing, it may be desirable to control the temperature of the metal product before, during, or after various processing steps. For example, it may be desirable to heat the metal strip before performing certain processes, or it may be desirable to maintain heat in the metal strip for a period of time without allowing the metal strip to cool above a minimum temperature. Temperature control may generally involve adding or removing thermal energy to or from the metal strip.

[0005] Various techniques exist for applying thermal energy to metal strip. Various techniques, particularly direct contact techniques, can induce undesirable effects on the metal strip, such as surface scratches, the accumulation of emissions on the surface (e.g., carbon from direct impingement flame or indirect flame heating sources), or other such undesirable results. Other techniques attempt to heat the metal strip without contact but are unable to efficiently transfer thermal energy to the metal strip. Some other problems associated with current techniques include high installation and / or maintenance costs, occupying significant production space, limiting the mobility of the metal strip being processed, and inducing undesirable effects on the metal strip. Summary of the Invention

[0006] The term "embodiments" and similar terms are intended to broadly refer to all of the subject matter of this disclosure and the claims that follow. Statements containing these terms should be understood neither to limit the subject matter described herein nor to limit the meaning or scope of the claims that follow. The embodiments of the disclosure covered herein are defined by the claims that follow, not this Summary. This Summary is a broad overview of various aspects of the disclosure 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 alone 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 disclosure, any or all drawings, and each claim.

[0007] Some embodiments of the present disclosure include rotary magnetic heaters and systems incorporating the rotary magnetic heaters, the rotary magnetic heater comprising: an upper rotor vertically offset from a lower rotor defining a gap therebetween for receiving a moving metal strip; at least one motor coupled to at least one of the upper rotor and the lower rotor for rotating at least one of the upper rotor and the lower rotor to induce a moving and time-varying magnetic field through the gap for heating the moving metal strip; and a pair of support arms each coupled to one of the upper rotor and the lower rotor for adjusting the gap.

[0008] In some embodiments, the rotary magnetic heater further includes an additional upper rotor vertically offset from the additional lower rotor, defining a gap therebetween for receiving the moving metal strip, and an additional pair of support arms each coupled to one of the additional upper rotor and the additional lower rotor to adjust the additional gap. The rotary magnetic heater may include at least one actuator coupled to at least one of the pair of support arms and the additional pair of support arms to adjust the gap in response to a signal, and a controller coupled to the at least one actuator to provide the signal. The rotary magnetic heater may include a sensor coupled to the controller to provide a measurement to the controller, the controller being configured to provide the signal based on the measurement. In some cases, the additional upper rotor is laterally offset from the additional lower rotor such that an overlap between the upper rotor and the lower rotor is less than the width of the moving metal strip. In some cases, the rotary magnetic heater may include an idler roller coupled to an extendable support arm movable between an extended position and a retracted position, at least one of the upper rotor and the lower rotor coupled to the extendable support arm, and a moving metal strip passing adjacent to the upper rotor and the lower rotor when the extendable support arm is in the extended position and the moving metal strip passing away from the upper rotor and the lower rotor when the extendable support arm is in the retracted position. In some cases, the rotary magnetic heater may include at least one magnetic flux conductor positioned adjacent to at least one of the upper rotor and the lower rotor to direct magnetic flux from at least one of the upper rotor and the lower rotor into the gap.

[0009] In some embodiments, a method includes passing a metal strip through a gap defined between an upper rotor and a lower rotor of a first magnetic rotor set, passing the metal strip through an additional gap defined between an additional upper rotor and an additional lower rotor of a second magnetic rotor set, rotating the first magnetic rotor set to induce a moving and time-varying magnetic field in the gap to heat the metal strip, rotating the second magnetic rotor set to induce the additional moving and time-varying magnetic field in the additional gap to heat the metal strip, and adjusting at least one of the gap and the additional gap so that tension (e.g., tension deviation) induced in the metal strip by the first magnetic rotor set is compensated for by the second magnetic rotor set. In some cases, the method includes measuring the metal strip, and adjusting at least one of the gap and the additional gap includes making the adjustment based on the measurement. In some cases, the method includes adjusting a longitudinal position of at least one of the first magnetic rotor set and the second magnetic rotor set. In some cases, the method includes adjusting a lateral position of at least one rotor of at least one of the first magnetic rotor set and the second magnetic rotor set.

[0010] Provided herein are systems and methods for curing a coating applied to a metal strip. The coating may include a paint, lacquer, laminate, pretreatment, adhesion promoter, corrosion inhibitor, or any suitable coating applied to a metal strip. One exemplary system for curing a coating includes a curing chamber and multiple rotors, each rotor having one or more magnets. The multiple magnets may be permanent magnets and / or electromagnets. The curing chamber includes appropriate inlets and outlets for passing the coated metal strip through the curing chamber.

[0011] The multiple rotors can be positioned within the cure chamber relative to the coated metal strip moving through the cure chamber in any suitable arrangement. In one non-limiting configuration, at least one upper magnetic rotor is positioned above the coated metal strip and at least one lower magnetic rotor is positioned below the coated metal strip. The at least one upper magnetic rotor can be aligned with the at least one lower magnetic rotor to create a substantially vertical cure stack, or the at least one upper magnetic rotor can be offset from the at least one lower magnetic rotor to create an offset cure stack. The system can have multiple cure stacks. In some examples, the rotors comprising each cure stack include counter-rotating rotors. In some cases, each cure stack provides individual heating zones that are individually and precisely controllable and instantly adjustable. In some cases, the multiple rotors can be positioned outside the cure chamber, and the walls of the cure chamber between the coated metal strip and the multiple rotors can be made of a non-conductive and non-magnetic material.

[0012] In some cases, the system includes only the upper magnetic rotor. In other cases, the system includes only the lower magnetic rotor. Each magnetic rotor or a subset of the magnetic rotors may be an individual heating zone that may be individually and precisely controllable and instantly adjustable.

[0013] The system is configured to heat the coated metal strip and the coating on the coated metal strip by induction heating. In particular, rotating one or more magnetic rotors positioned relative to the coated metal strip induces a moving or time-varying magnetic field in the metal strip. The changing magnetic field generates currents (e.g., eddy currents) in the metal strip, thus heating the metal strip (and subsequently any coating applied to the metal strip) via induction heating. In some cases, the system is configured such that the magnetic flux from the magnetic rotors is concentrated at the surface of the metal strip.

[0014] In some configurations, the magnetic rotor above the metal strip rotates in a first direction and the magnetic rotor below the metal strip rotates in a second, opposite direction.

[0015] The magnets may be embedded within each rotor or may be coupled to a surface of each rotor in any suitable manner. In some examples, at least a portion of each magnet is exposed. The magnets or a subset of the magnets may be the same length as the longitudinal length of each rotor and may be embedded or attached along the longitudinal axis of each rotor. In other examples, at least some of the magnets are shorter or longer than the longitudinal length of each rotor.

[0016] Also provided herein are methods for curing a coating on a metal strip. One exemplary method includes rotating multiple rotors, each rotor including at least one magnet, generating heat from the multiple rotors, and passing the coated metal strip through a curing chamber, where passing the coated metal strip through the curing chamber includes passing the coated metal strip through the multiple rotors. In some cases, each rotor rotates at at least 200 revolutions per minute (RPM).

[0017] Also provided herein is a method for heating a heat transfer medium, the method including rotating rotors, each rotor including at least one magnet, generating heat from the rotors, and passing the heat transfer medium adjacent to the rotors. In some cases, the rotors may rotate at at least 200 revolutions per minute (RPM). The generation of heat from the magnetic rotors may be instantaneous, precisely controlled, and instantly adjustable. Heat may be transferred to the heat transfer medium by induction heating. In particular, rotating one or more magnets positioned relative to a coated metal strip induces a moving or time-varying magnetic field within the metal strip. The changing magnetic field creates currents (e.g., eddy currents) within the metal strip, thus heating the metal strip (and subsequently any coating applied to the metal strip) via induction heating. The heat transfer medium may include water, liquid silicon, air, oil, any suitable phase change material, or any suitable gas or liquid, and the heat transfer medium may supply heat to a process or location adjacent to a curing chamber. [Brief explanation of the drawings]

[0018] This specification refers to the following accompanying drawings, in which the use of like reference numbers in different drawings is intended to illustrate the same or similar elements.

[0019] [Figure 1] FIG. 1 is a side view of a rotary magnetic heater according to certain aspects of the present disclosure. [Figure 2] FIG. 1 is a top view of a rotary magnet heater according to certain aspects of the present disclosure. [Figure 3] FIG. 1 is an axonometric view of a rotary magnet heater according to certain aspects of the present disclosure. [Figure 4] FIG. 2 is a cross-sectional side view of a permanent magnet rotor according to certain aspects of the present disclosure. [Figure 5] FIG. 1 illustrates a top view of a rotary magnet heater with an offset rotor, according to certain aspects of the present disclosure. [Figure 6]FIG. 1 is an axonometric view of a rotary magnet heater with an offset rotor, according to certain aspects of the present disclosure. [Figure 7] FIG. 1 is a side view of a rotary magnet heater having a magnetic flux conduit according to certain aspects of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram of a continuous casting system utilizing a rotary magnetic heater, according to certain aspects of the present disclosure. [Figure 9] 1 is a schematic representation of a metalworking process using a rotary magnetic heater, according to certain aspects of the present disclosure. [Figure 10] 1 is a schematic representation of a rotary magnet heater control system according to certain aspects of the present disclosure. [Figure 11] 1 is a flowchart illustrating a process for using a rotary magnetic heater, according to certain aspects of the present disclosure. [Figure 12] FIG. 1 is a side view of a serpentine rotary magnet heater according to certain aspects of the present disclosure. [Figure 13] FIG. 1 is a side view of an extendable rotary magnetic heater in an extended position, according to certain aspects of the present disclosure. [Figure 14] FIG. 1 is a side view of an extendable rotary magnetic heater in a retracted position, according to certain aspects of the present disclosure. [Figure 15] FIG. 1 is a side view of a serpentine rotary magnet heater using a combined idler rotor, according to certain aspects of the present disclosure. [Figure 16] FIG. 1 illustrates a side view of a rotary magnet heater with longitudinal gap control, according to certain aspects of the present disclosure. [Figure 17] FIG. 1 is a side view of a rotary magnet heater having a single rotor rotor set, according to certain aspects of the present disclosure. [Figure 18] FIG. 1 is a side view of a rotary magnet heater having a rotor set of a single rotor facing a metal plate, according to certain aspects of the present disclosure. [Figure 19] FIG. 1 is a side view of a rotary magnet heater having a rotor set of a single rotor facing a roller, according to certain aspects of the present disclosure. [Figure 20]FIG. 1 is a side view of a rotary magnetic heater that is movable relative to a stationary metal strip, according to certain aspects of the present disclosure. [Figure 21] FIG. 1 is an axonometric view of a rotary magnet heater having multiple sub-rotors, according to certain aspects of the present disclosure. [Figure 22] FIG. 1 illustrates a top view of a rotary magnet heater having multiple sub-rotors, according to certain aspects of the present disclosure. [Figure 23] 23 is a chart illustrating rotor speed and strip temperature of the rotor and metal strip of FIG. 22 under a first condition, according to certain embodiments of the present disclosure. [Figure 24] 23 is a chart illustrating rotor speed and strip temperature of the rotor and metal strip of FIG. 22 under a second condition, according to certain embodiments of the present disclosure. [Figure 25] FIG. 2 is a front view of a rotor illustrating a magnetic flux profile according to certain aspects of the present disclosure. [Figure 26] FIG. 1 is a front perspective view illustrating a rotor having a contoured magnetic rotor within a shell, according to certain aspects of the present disclosure. [Figure 27] FIG. 2 is a front perspective view illustrating a rotor having a magnetic flux concentrator according to certain aspects of the present disclosure. [Figure 28] FIG. 2 is a cross-sectional side view of a permanent magnet rotor having a magnetic flux concentrator according to certain aspects of the present disclosure. [Figure 29] FIG. 2 is a front view illustrating a rotor set including a variable flux rotor, according to certain aspects of the present disclosure. [Figure 30] FIG. 30 is a front view illustrating the rotor set of FIG. 29 after repositioning of the variable flux rotor, in accordance with certain aspects of the present disclosure. [Figure 31] FIG. 1 is a front view illustrating a rotor set including a flared flux rotor, according to certain aspects of the present disclosure. [Figure 32] 1A-1C are front views illustrating techniques for adjusting the amount of magnetic flux passing through a metal strip, according to certain aspects of the present disclosure. [Figure 33] FIG. 1 is a top view of a rotary magnet heater according to certain aspects of the present disclosure. [Figure 34]1 is a combined schematic and graph illustrating a magnetic heating and tension control system according to certain aspects of the present disclosure. [Figure 35] FIG. 1 is a front view of a rotor having a pair of rotor sleeves that provide a magnetic flux profile in accordance with certain aspects of the present disclosure. [Figure 36] FIG. 1 is an axonometric, partially schematic view illustrating a magnetic rotor on a metal strip with magnetic flux guides, according to certain aspects of the present disclosure. [Figure 37] FIG. 1 is an axonometric, partially schematic view illustrating a magnetic rotor on a metal strip with bar-shaped flux guides, according to certain aspects of the present disclosure. [Figure 38] FIG. 1 is an axonometric partial schematic view illustrating a magnetic rotor on a metal strip with edge shielding magnetic flux guides, according to certain aspects of the present disclosure. [Figure 39] FIG. 1 is an axonometric, partially schematic view illustrating a magnetic rotor on a metal strip with magnetic flux conduits, according to certain aspects of the present disclosure. [Figure 40] 1 is a schematic illustration of a curing chamber according to certain aspects of the present disclosure. [Figure 41] FIG. 1 is a perspective view illustrating an example of a magnetic rotor according to certain aspects of the present disclosure. [Figure 42] FIG. 2 is a cross-sectional view illustrating an example of a magnetic rotor according to certain aspects of the present disclosure. [Figure 43] FIG. 2 is a cross-sectional view illustrating an example of a magnetic rotor according to certain aspects of the present disclosure. [Figure 44] FIG. 2 is a cross-sectional view illustrating an example of a magnetic rotor according to certain aspects of the present disclosure. [Figure 45] 1 is a graph of the cure chamber temperature profile of a gas-fired cure chamber. [Figure 46] 1 is a graph of temperature rise rate compared to magnetic rotor speed, in accordance with certain aspects of the present disclosure. [Figure 47] 1 is a graph of the rate of temperature rise compared to the gap between magnetic rotors, in accordance with certain aspects of the present disclosure. [Figure 48]1 is a schematic illustration of a curing chamber and a heat transfer medium heated oven according to certain aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0020] Certain aspects and features of the present disclosure relate to rotary magnetic heaters for metal products such as metal strip, non-ferrous metal strip, and aluminum strip. The rotary magnetic heater may include one or more permanent magnet rotors positioned above and / or below a moving metal strip to induce a moving or time-varying magnetic field through the metal strip. The changing magnetic field may induce currents (e.g., eddy currents) in the metal strip, thus heating the metal strip. The magnetic rotor set may include one or more magnet rotors, such as a single magnet rotor or a pair of matched magnetic rotors on both sides of the metal strip, rotating at the same speed. Each magnetic rotor in the set may be positioned equidistant from the metal strip to avoid pulling the metal strip away from its path line. A downstream magnetic rotor set may be used in close proximity to an upstream magnetic rotor to offset the tension induced by the upstream magnetic rotor set. The use of one or more magnetic rotors and any other heating or control elements may induce a tailored temperature profile on the metal article. The tailored temperature profile may be a specific temperature profile across the width of the metal article, including a uniform or substantially uniform temperature profile.

[0021] As used herein, the terms "up," "down," "vertical," and "horizontal" are used to describe relative orientations to a metal strip as if it were moving horizontally with its top and bottom surfaces generally parallel to the ground. As used herein, the term "vertical" may refer to a direction perpendicular to a surface (e.g., top or bottom) of the metal strip, regardless of the orientation of the metal strip. As used herein, the term "horizontal" may refer to a direction parallel to a surface (e.g., top or bottom) of the metal strip, such as a direction parallel to the direction of travel of the moving metal strip, regardless of the orientation of the metal strip. The terms "up" and "down" may refer to a location beyond the top or bottom surface of the metal strip, regardless of the orientation of the metal strip. In some cases, the metal strip may move horizontally, vertically, or in any other direction, such as diagonally.

[0022] Rotary magnetic heaters may be used with any suitable metal strip capable of generating eddy currents in the presence of a moving and time-varying magnetic field, but may be particularly suitable for use with aluminum metal strip. As used herein, the terms vertical, longitudinal, and transverse may be used with respect to the metal strip being heated. The longitudinal direction may extend along the direction of travel of the metal strip through processing equipment, such as along the pass line through a continuous annealing, solution heat treatment (CASH) line or other equipment. The longitudinal direction may be parallel to the top and bottom surfaces of the metal strip and the side edges of the metal strip. The longitudinal direction may be perpendicular to the transverse and vertical directions. The transverse direction may extend between the side edges of the metal strip. The transverse direction may extend in a direction perpendicular to the longitudinal and vertical directions. The vertical direction may extend between the top and bottom surfaces of the metal strip. The vertical direction may be perpendicular to the longitudinal and transverse directions.

[0023] Although aspects and features of the present disclosure are described herein with respect to metal strip, such as continuously cast or non-coiled metal strip, the present disclosure may also be used with any suitable metal product, such as foil, sheet, plate, plate, rolled plate, or other metal product. Aspects and features of the present disclosure may be particularly suitable for any metal product having flat surfaces. Aspects and features of the present disclosure may be particularly suitable for any metal product having parallel or substantially parallel opposing surfaces (e.g., top and bottom surfaces). As used throughout this application, substantially parallel may include parallel or, as appropriate, within 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, or 10° of parallel. As used throughout this application, substantially perpendicular may include perpendicular or, as appropriate, within 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, or 10° of perpendicular. In some cases, substantially parallel or substantially perpendicular may include elements that deviate from parallel or perpendicular by more than 10°, respectively.

[0024] Precise heating control can be achieved when using rotary magnetic heaters. Such precise control can be achieved through manipulation of various factors, including the strength of the magnets in the rotor, the number of magnets in the rotor, the orientation of the magnets in the rotor, the size of the magnets in the rotor, the speed of the rotor, the size of the rotor, the vertical gap between vertically offset rotors in a single rotor set, the laterally offset arrangement of rotors in a single rotor set, the longitudinal gap between adjacent rotor sets, the thickness of the strip being heated, the vertical distance between the rotor and the strip being heated, the advancement speed of the strip being heated, and the number of rotor sets used. Other factors can be controlled as well. In some cases, control of one or more of the aforementioned factors, among others, can be based on a computer model, operator feedback, or automatic feedback (e.g., based on signals from real-time sensors).

[0025] Each magnetic rotor may include one or more magnetic sources, such as permanent magnets or electromagnets. Permanent magnet rotors may be preferred in some cases and may achieve more efficient results than rotors with internal electromagnets. Each magnetic rotor may rotate about an axis of rotation that is perpendicular or approximately perpendicular to the longitudinal axis of the metal strip passing adjacent to the rotor. In other words, each magnetic rotor may rotate about an axis of rotation that is perpendicular or approximately perpendicular to the processing direction (e.g., the rolling direction or downstream direction) of the metal strip. The axis of rotation of the magnetic rotor may also be parallel or approximately parallel to the lateral width of the metal strip. In one example, a magnetic rotor that is perpendicular to the downstream direction and parallel to the lateral width of the metal strip may advantageously provide heating power and tension control (e.g., longitudinal tension control) simultaneously. In some cases, the rotation axis of the magnetic rotor may be perpendicular to the processing direction and coplanar with the width of the metal strip, in which case the rotation axis may be intentionally angled (e.g., angled at one end of the magnetic rotor closer to the metal strip than the other end) to achieve desired control over the temperature profile in the metal article. In some cases, the rotation axis of the magnetic rotor may be perpendicular to the height of the metal strip and fall within a plane parallel to and spaced apart from the plane formed by the width of the metal strip and the processing direction, in which case the rotation axis may be intentionally angled (e.g., angled at one end of the magnetic rotor downstream than the other end) to achieve desired control over the temperature profile in the metal article. In some cases, the rotation axis of the magnetic rotor may be angled differently. The rotational motion of the rotor causes a magnetic source to induce a moving or changing magnetic field. The rotor may be rotated via any suitable method, including via the synchronized motion of a rotor motor (e.g., electric motor, pneumatic motor, or other) or a nearby magnetic source (e.g., another magnetic rotor).

[0026] In contrast to stationary electromagnets, the use of a rotating magnetic rotor can enable improved efficiency and more uniform heating of the metal strip. Using a stationary electromagnet to vary the induced magnetic field across the width of the strip can create local hot spots within the strip. Varying induced magnetic fields can be caused by natural variations in the windings of different stationary electromagnets. Variations in electromagnet windings can result in locations generating more heat than adjacent lateral locations. Local hot spots can deform the strip unevenly and cause other manufacturing defects. In contrast, permanent magnets may contain some level of inherent magnetic variation across dimensions or from magnet to magnet, but this variation is automatically averaged out due to the rotation of the permanent magnets within the rotor. No single permanent magnet is held in any lateral stationary position, and therefore an average magnetic field is applied by the rotating permanent magnets. Therefore, a rotating magnetic rotor can uniformly heat the metal strip in a more controlled manner. When electromagnets are used in a rotary magnet heater, variations between different electromagnets can be averaged out due to the rotation of the rotor. This averaging out of fluctuations does not occur in a static electromagnet.

[0027] A rotor set may include one or more rotors. In some cases, a rotor set includes two vertically offset rotors, forming a gap between them through which the metal strip can pass. The size of the gap (e.g., vertical gap) between the rotors in a rotor set may be controlled through the use of a suitable actuator, such as a linear actuator (e.g., a hydraulic piston, screw drive, or other such actuator). The vertical position of each rotor in a rotor set may be individually controllable, or the vertical positions of both the upper and lower rotors of a rotor set may be simultaneously controllable by a single actuator responsible for controlling the vertical gap. The vertical gap may be centered about the desired or actual path line of the metal strip. In some cases, the rotors of a rotor set will rotate synchronously due at least to magnetic attraction between them. For example, when the south pole of the upper rotor points downward toward the strip, the north pole of the lower rotor may point upward toward the strip.

[0028] In some cases, a rotor set may include a single rotor located on either side of the metal strip. In some cases, a rotor set including a single rotor may optionally include an opposing element located on the opposite side of the metal strip from the rotor. The opposing element may facilitate the movement of magnetic flux through the metal strip and / or provide mechanical support to the metal strip. Examples of suitable opposing elements include a stationary plate (e.g., an iron or steel plate) and a support roller (e.g., a steel roller). In some cases, the use of a single rotor may facilitate self-regulation of temperature increases induced in the metal strip due to the moving magnetic field. In some cases, the use of an odd number of rotors (e.g., 1, 3, 5, or 7 rotors) in a rotor set may result in uneven amounts of force being applied to the metal strip, causing it to move away from the desired path line. In some cases, additional support (e.g., a support roller or compressed fluid / air nozzle) may be provided to maintain the metal strip on the desired path line. In some cases, the position of the rotors within the rotor set may be staggered to keep the metal strip close to the desired pass line.

[0029] A rotor set may rotate in a "downstream" direction or an "upstream" direction. As used herein, a rotor set rotating in a downstream direction provides a non-zero force that urges the metal strip in the direction of its longitudinal advancement. For example, when the metal strip is viewed from the side as the metal strip moves to the right in its longitudinal advancement, the upper rotor of a rotor set rotating in a downstream direction may rotate counterclockwise, while the lower rotor rotates clockwise. As used herein, a rotor set rotating in an upstream direction provides a non-zero force that urges the metal strip in the direction opposite to its longitudinal advancement. For example, when the metal strip is viewed from the side as the metal strip moves to the right in its longitudinal advancement, the upper rotor of a rotor set rotating in an upstream direction may rotate clockwise, while the lower rotor rotates counterclockwise.

[0030] In some cases, a magnetic flux concentrator may be used adjacent to the rotor. The magnetic flux concentrator may be any suitable material capable of redirecting magnetic flux. The magnetic flux concentrator may receive magnetic flux from magnets in the rotor near or not directly facing the strip and redirect the magnetic flux toward the strip (e.g., perpendicular to the top or bottom surface of the strip). The magnetic flux concentrator may also provide the benefit of magnetic shielding between the rotor and adjacent equipment other than the heated metal strip. For example, the magnetic flux concentrator may allow adjacent longitudinally offset rotor sets to be positioned closer to each other with less magnetic interaction between the two. The magnetic flux concentrator may be made of any suitable material, including silicon alloy steel (e.g., electrical steel). The magnetic flux concentrator may include multiple laminations. The magnetic flux concentrator may be a magnetic flux diverter or a magnetic flux controller. When a magnetic flux concentrator is used, the rotor may be able to achieve efficient results at a lower rotational speed, and the magnets may be able to be positioned farther from the metal strip.

[0031] A rotary magnetic heater may include one or more rotor sets. In some cases, the rotary magnetic heater includes at least two rotor sets, including an upstream rotor set and a downstream rotor set. When at least two rotor sets are used, one rotor set may offset any longitudinal tension induced by another rotor set. In some cases, multiple rotor sets may cancel longitudinal tension induced by a single rotor set, or a single rotor set may cancel longitudinal tension induced by multiple rotor sets. In some cases, the total number of rotor sets is an even number (e.g., 2, 4, 6, etc.). As used herein, a rotor group is a collection of two or more rotor sets that provides a net effect on the longitudinal tension of the metal strip that is 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% or less. For example, a rotor group may include an upstream magnetic rotor set that rotates upstream, thereby inducing tension in the longitudinal direction of the metal strip, and a downstream magnetic rotor set that rotates downstream, thereby reducing or counteracting the tension induced by the upstream rotor set. Because the properties of the metal strip may change as heat is applied by each rotor set, the properties of each rotor set within the rotor group may be controlled to appropriately counteract the induced tension. For example, the vertical gap of a first rotor set may be dynamically adjusted to induce the appropriate tension that is counteracted or counteracted by a second rotor set with a known or fixed vertical gap. While adjusting the vertical gap between the rotors may be desirable to control the amount of tension applied to the metal strip, other variables, such as rotational speed, may be adjusted as well.

[0032] Due to the nature and orientation of the rotor within the rotary magnet heater, the rotary magnet heater can be easily installed, removed, and maintained in a processing facility. Rotary magnet heaters can occupy less space than stationary electromagnetic induction heaters. Furthermore, many stationary electromagnetic induction heaters require a coil wrapped around the metal strip being heated, thus requiring complex connections and / or manipulations to remove the metal strip from the induction coil. When needed, the metal strip can be quickly and easily removed from the rotary magnet heater. In some cases, vertical and / or lateral control of the rotary magnet heater can be used to move the rotary magnet heater away from the metal strip for maintenance, to route the strip through processing equipment, or simply when additional heating is not desired for a portion of the metal strip.

[0033] Current magnetic heating technologies, such as stationary electromagnetic induction heaters, generally provide inefficient heating, such as heating with an efficiency of 50%, 45%, or 40% or less. Rotary magnet heaters, as disclosed herein, can be operated at very high efficiencies, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% or more. Furthermore, rotary magnet heaters can provide the same amount of heating in less space than many current magnetic or electromagnetic heating technologies. In addition, the vertical gap between the rotors can be adjusted in rotary magnetic heaters, allowing for more space to be created if the metal strip begins to deviate from the desired path line, thereby preventing the metal strip from contacting the rotary magnet heater and potentially causing damage to the heater or the metal strip. In contrast, many current magnetic heating technologies, such as stationary electromagnetic induction heaters, do not allow for their gaps to be adjusted, which can result in undesired collisions if the metal strip begins to deviate from the desired path line.

[0034] Additionally, the use of permanent magnets may require less energy to apply the desired thermal energy compared to electromagnets, especially as operating temperatures increase. If the operating temperature increases too much, the electromagnets will no longer operate properly and significant resources must be expended to adequately cool them. In contrast, permanent magnets may operate at higher temperatures, do not generate heat themselves, and may require less cooling.

[0035] If necessary, temperature controls may be applied to the rotor or any adjacent equipment to maintain high-efficiency operation and / or safe operating conditions. Temperature controls may include forced air, liquid, or other fluid heat exchange mechanisms. Temperature controls may be combined with flux concentrators to ensure that equipment adjacent to the rotor does not overheat.

[0036] Rotary magnetic heaters may be particularly suitable for processes in which physical contact with the metal strip is undesirable. For example, rotary magnetic heaters may be particularly useful in CASH lines (e.g., as reheaters or preheaters for flotation furnaces). In CASH lines, the metal passes through multiple sections under low tension. Some CASH lines may be up to about 800 meters or longer in length. In certain sections, such as the furnace and cooling sections, the metal strip may not be supported by rollers or other contact devices. The metal strip may pass through unsupported sections of about 100 meters or longer. As future CASH lines are developed, these lengths may become longer. In the unsupported sections, the metal strip may be levitated on a cushion of fluid (e.g., gas or air). It may be desirable to supply heat (e.g., thermal energy) to the metal strip during these unsupported sections. Therefore, it may be desirable to use non-contact rotary magnetic heaters within these sections. Optionally, the addition of rotary magnet heaters before these unsupported sections can help heat the strip rapidly, thereby minimizing the need for longer unsupported sections. Furthermore, a strip passing through a set of vertically oriented non-contact rotary magnets experiences a vertical repulsive force from each magnet, resulting in vertical stabilization of the strip in the center of the gap between the rotary magnets.

[0037] Certain embodiments of the present disclosure may be particularly well suited for drying metal strip. One or more rotary magnetic heaters may heat the metal strip without contacting the metal strip, facilitating evaporation of liquid on the surface of the metal strip. Certain embodiments of the present disclosure may be particularly well suited for reheating the metal strip over short distances. In some cases, the rotary magnetic heater may rapidly reheat the metal strip following a quench or the like (e.g., after a rapid quench after hot rolling to specifications).

[0038] Certain aspects of the present disclosure may be particularly well-suited for controlling strip temperature without imparting undesirable temperature changes to lubricants or other fluids on the surface of the metal strip. For example, some lubricants may have undesirable properties at high temperatures. When metal strip is heated in a furnace or via hot air or direct thermal shock, the lubricant on the surface of the metal strip may be heated from the high-temperature furnace, hot air, or direct flame and may rapidly reach an undesirable temperature before the metal strip itself is heated to the desired temperature for the desired time. However, with the use of a rotary magnetic heater, the magnetic field changes induced by the relative motion of the magnet with respect to the metal strip heat the metal strip itself without directly imparting a temperature change to the lubricant. In such cases, the lubricant may be heated substantially or solely by heat conduction from the metal strip. Thus, the metal strip may be heated to the desired temperature for the desired time with reduced or no risk of the lubricant reaching an undesirable temperature. In some cases, heating using other techniques may pose a risk of overheating the coating.

[0039] Some conventional techniques for curing coatings, such as gas-fired ovens and infrared heaters, heat the coating from the outside inward (e.g., from the outer surface of the coating toward the interface between the coating and the metal article). Therefore, conventional techniques tend to heat the surface of the coating first, which often has a higher concentration of paint or other material than that further below the surface of the coating, which may contain a higher concentration of solvent. As a result, current techniques use very specifically designed solvents to ensure that bubbles do not form during heating, which can adversely affect the surface of the coating, which is heated first in conventional techniques. In contrast, certain embodiments of the present disclosure allow the coating to be heated from the inside outward (e.g., from the interface with the metal article toward the surface of the coating). Therefore, because the surface of the coating is the last part of the coating to be heated, solvent bubbles are less of a concern. Therefore, certain embodiments of the present disclosure may allow for the use of more different types of solvents or solvents with more relaxed requirements.

[0040] Additionally, some conventional techniques for curing coatings require the presence of a high-temperature atmosphere near the coating being cured, such as hot gases in a gas-fired oven or hot air adjacent to an infrared heater. Because solvents can evaporate into the ambient atmosphere, the risk of explosion or fire increases as the temperature of the atmosphere increases. For example, a 300°C atmosphere may have a much higher explosion potential than a room-temperature atmosphere. Therefore, conventional techniques may be effectively limited by safety concerns, which may result in slower line or processing speeds and a reduction in the amount or type of solvent that can be used for a particular coating. In contrast, certain embodiments of the present disclosure allow the coating to be heated from the inside out, which can occur in a much lower ambient atmosphere than conventional techniques, such as at or near ambient temperature (room temperature). Therefore, certain embodiments of the present disclosure may allow for faster line or processing speeds and the use of larger amounts of solvent and different types of solvents that may not be possible with conventional techniques.

[0041] Certain aspects of the present disclosure may be particularly well-suited for increasing or decreasing tension in a metal strip without contacting the metal strip while simultaneously providing heat to the metal strip. For example, when a metal strip is to be heated after it is unwound from a coil, one or more rotors all rotating in the same direction (e.g., upstream toward the unwinder) may act to decrease the tension in the metal strip after each rotor. Similarly, when a metal strip is to be heated before it is wound onto a coil, one or more rotors all rotating in the same direction (e.g., downstream toward the rewinder) may increase the tension in the metal strip while simultaneously increasing the temperature of the metal strip as it approaches the rewinder. Tension may be controlled anywhere during metal processing, such as before or after any suitable processing equipment, including equipment other than unwinders and rewinders.

[0042] Certain embodiments of the present disclosure may be particularly well suited for heating a surface portion of a metal strip to a desired depth. For example, a rotary magnetic heater may be positioned to heat the surface of the metal strip to a desired depth (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the thickness of the metal strip) without substantially heating the center of the metal strip.

[0043] In some cases, rotary magnet heaters can be particularly useful for fusion products where the metal strip includes a core section made of a different material than the cladding section. The adjustable parameters of the rotary magnet heater can be manipulated to achieve the desired results based on the type of material selected for the cladding and core, and based on the thickness of the cladding.

[0044] In some cases, the amount of magnetic flux applied to the metal strip can be adjusted by various techniques. The applied magnetic flux of a rotary magnetic heater can be adjusted offline (e.g., before passing the metal strip adjacent to the rotary magnetic heater) or dynamically (e.g., by adjusting while the metal strip is passing adjacent to the rotary magnetic heater). In some cases, the amount of magnetic flux applied by the rotary magnetic heater can vary along the width of the heater. For example, when a constant magnetic flux rotor is used, the metal strip may have a temperature profile (e.g., a temperature profile along the width of the metal strip) that includes hot spots near the edges and cool spots just inside the edges. To eliminate such temperature profiles and instead attempt to achieve a flat temperature profile, the rotary magnetic heater can have a magnetic flux that varies across its width, such as providing increased magnetic flux at the locations of the cool spots and decreased magnetic flux at the locations of the hot spots. As described herein, other techniques can be used to eliminate hot spots and achieve a desired temperature profile (e.g., a regulated temperature profile) across the metal article, such as a uniform temperature profile across the lateral width of the metal article.

[0045] The magnetic flux of a rotary magnetic heater can be adjusted offline or dynamically in various ways. In some cases, magnetic flux concentrators can be added to the rotor to increase the magnetic flux therethrough where desired. For example, magnetic steel, also known as laminated steel or transformer steel, can be used as a suitable magnetic flux concentrator. In some cases, magnetic flux concentrators can be positioned adjacent to the radial end of each individual magnet at a specific lateral position on the rotor. In some cases, stronger or weaker magnets can be selected to be included in specific locations within the rotor. In some cases, larger magnets (e.g., larger diameter or thickness) can be used where increased magnetic flux is desired, and smaller magnets can be used where less magnetic flux is desired. In some cases, magnetically opaque or magnetically translucent materials can be used to suppress magnetic flux in undesired locations. In some cases, a rotor may consist of axially aligned sub-rotors. To achieve increased or decreased magnetic flux at various locations within the rotor, the sub-rotors at those locations can rotate faster or slower than the other sub-rotors. In some cases, each sub-rotor may be individually controlled, such as via an individual motor. In some cases, each sub-rotor may be mechanically coupled to one another or may be coupled to a single drive motor using gears to achieve desired speeds relative to one another. In some cases, a transmission (e.g., a transmission with multiple gear sizes or a continuously variable transmission) may allow the speed of certain sub-rotors relative to the speed of other sub-rotors to be dynamically adjusted.

[0046] The magnets (e.g., magnetic sources) in the rotor can have any desired magnetic flux profile. In some cases, a flat profile may be desired. In some cases, the magnetic flux profile may be designed to minimize the risk of hot or cold spots in the metal strip. In some cases, the magnetic flux profile may be variable in a manner that provides improved flexibility to provide different amounts of magnetic flux through the metal strip depending on the rotor position and / or orientation. In one example, a rotor may have a magnetic flux profile that takes on a continuously variable crown shape, optionally positioned opposite a rotor with a complementary magnetic flux profile. Controlling the rotor position and / or orientation may allow the amount of magnetic flux passing through the metal strip to be adjusted as desired.

[0047] In some cases, the amount of magnetic flux applied to the metal strip can be adjusted by inserting a magnetically translucent or magnetically opaque material between the rotor and the metal strip.

[0048] In use, a rotary magnet heater provides heat to an adjacent metal strip by inducing eddy currents within the metal strip. The induced eddy currents result from a moving, time-varying magnetic field generated by the rotor and the relative motion of the metal strip past the rotor. The moving, time-varying magnetic field can be modeled into up to four subparts: a first part due to the motion of the metal strip past the rotor; a second part due to the rotation of the magnets around the rotor's axis of rotation; a third part due to the rotation of the magnets' orientation as they rotate around the rotor's axis of rotation; and a fourth part due to the attenuation or concentration of magnetic flux by additional devices, such as shielding or flux concentrators, in localized areas along the strip. Modeling the heat generation of a moving metal strip is further complicated by changes in the metal strip's inductance and / or resistivity as its physical properties (e.g., temperature) change. Surface effects (e.g., non-uniform heating across the strip's vertical height) and edge effects (e.g., non-uniform heating across the strip's lateral width) can also further complicate the modeling. Through numerous models and experiments, it has been found that various aspects and features of the present disclosure, as described in further detail herein, are particularly suited for heating metal strip with high efficiency.

[0049] Certain aspects and features of the present disclosure are described with reference to a moving metal strip, such as a moving metal strip passing adjacent to a rotary magnetic heater. Concepts applicable to a moving metal strip may be equally applicable to stationary metal (e.g., stationary metal strip, plate, rolled plate, or other metal product) adjacent to a moving rotary magnetic heater. For example, instead of the metal strip moving adjacent to a rotor, the metal strip may be held stationary while the rotor moves along the length of the stationary metal strip, such as while the rotor also rotates. In addition, certain aspects and features of the present disclosure may be suitable for use with moving or stationary pieces of metal other than metal strip. For example, a rotary magnetic heater may be used with rolled bar, extrusions, thick plates (e.g., greater than 10 mm thick), metal greater than 50 mm or greater than 100 mm thick, rods greater than 400 mm to 500 mm in diameter, asymmetric metal products, or other suitable metal products.

[0050] In some cases, the rotary magnetic heaters described herein can be positioned around the metal product. Magnetic rotors such as those described herein can be symmetrically positioned around the metal product, such as on adjacently opposing faces of a metal strip (e.g., upper and lower rotors) or three directions around a metal bar (e.g., equally spaced 120° from each other when viewed in the direction of relative motion of the metal bar with respect to the magnetic rotors), or can be equally spaced. The placement of the magnetic rotors around the metal product can be selected to achieve desired heating of the metal product. In some cases, the placement of the magnetic rotors can focus maximum magnetic flux through the center of the metal product (e.g., a metal bar) to provide more heat to the center of the metal product than to the outer surfaces of the metal product, thus allowing the center to heat faster than the outer surfaces of the metal product. Any number of magnetic rotors may be used in an arrangement, such as one magnetic rotor, two magnetic rotors (e.g., positioned at a 180° angle from one another), three magnetic rotors (e.g., positioned at a 120° angle from one another), four magnetic rotors (e.g., positioned at a 90° angle from one another), or more. In some cases, the magnetic rotors in an arrangement may be symmetrically oriented or equally spaced about a central axis (e.g., the longitudinal axis of the metal strip), while in some cases, the magnetic rotors may be arranged asymmetrically or with an uneven distribution about the metal product.

[0051] Certain aspects and features of the present disclosure relate to rotary magnet heaters that provide a varying magnetic field (e.g., varying magnetic flux) through a metal strip. In some cases, other sources of varying magnetic fields may be used, such as electromagnets, magnets moving in a non-circular or elongated path such as along a belt (e.g., similar to a tank tread), magnets rotating on a disk, or other such sources of varying magnetic fields. In some cases, the rotary magnet heaters described herein may have advantages over other sources of varying magnetic fields, although other sources of varying magnetic fields may also be used when applicable.

[0052] Certain aspects and features of the present disclosure can be used to provide spot heating at localized locations on a metal strip or other metal product. The locations can be defined in one, two, or three dimensions. For example, the locations can be defined as locations along the lateral width of the metal strip, thus resulting in magnetic heating along the entire length of the metal strip at that lateral width. In another example, the locations can be defined as locations along both the lateral width and longitudinal length of the metal strip, thus resulting in magnetic heating along a certain portion of the metal strip (e.g., a 10 cm x 10 cm square portion of the metal strip repeated every 1 meter). This two-dimensional localized heating can be achieved by varying the relative motion between the metal strip and the magnetic heater (e.g., using a stationary metal strip, a moving magnetic heater, or otherwise). In some cases, three-dimensional localization can be provided by concentrating magnetic flux at a specific depth in the metal strip. This type of spot heating can provide a magnetic heater with spot annealing capabilities, allowing certain portions of a metal product (e.g., a metal strip) to be annealed without annealing other portions of the metal product. This spot annealing can be particularly useful when high strength is desired in the metal product, but improved forming capabilities are required in the area where the stamping process is performed.

[0053] In some cases, painted or coated material strips, such as metal strips, require a subsequent curing procedure to remove water, solvents, and / or other suitable additives contained in the coating due to the application procedure. Curing may be required, for example, to provide a coating that is smooth and well-adhered to the material strip. Curing parameters can affect the coating properties of the metal strip, including adhesion, gloss, color, surface lubricity, overall sheet shape, and mechanical properties, to name a few. According to certain aspects and features of the present disclosure, a magnetic rotor can be used to cure a coating on a metal article, such as a metal strip. One exemplary system includes a rotor with magnets housed within a curing chamber. The rotating rotor with associated magnets can induce a moving or time-varying magnetic field within the coated metal strip. The changing magnetic field can induce currents (e.g., eddy currents) within the metal strip, thus heating the metal strip and its coating. Additionally, the rotating magnet can be used to heat water or any other suitable heat exchange material for use in other systems or processes.

[0054] In some non-limiting examples, a system for curing a coating on a metal or other material strip includes a curing chamber and multiple rotors, each of the rotors including at least one magnet. Suitable coatings cured by the disclosed systems and methods include organic coatings, inorganic coatings, hybrid organic-inorganic coatings, water-based coatings, solvent coatings, paints, adhesives, lacquers, powder coatings, and / or laminates, or others.

[0055] In some cases, a magnetic rotor can be useful for providing heating for subsequent metal articles that have different thermal requirements (e.g., desired temperature set points). For example, a first metal article and a subsequent metal article may be processed immediately one after the other on the same piece of equipment, and the use of a magnetic rotor to provide heating can allow the system to rapidly adjust from the temperature set point for the first metal article to the temperature set point for the second metal article. This rapid adjustment can help reduce the amount of material that must be discarded during the transition between subsequent metal articles.

[0056] These illustrative examples are provided to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosed concepts. The following section describes various additional features and examples with reference to the drawings, in which like numerals indicate like elements and directional descriptions are used to describe exemplary embodiments, but as such should not be used to limit the disclosure. Elements included in the examples herein may not be drawn to scale.

[0057] FIG. 1 is a side view of a rotary magnetic heater 100 according to certain aspects of the present disclosure. The rotary magnetic heater 100 may include any number of rotors 108, 110, 112, 114 and rotor sets 104, 106. As seen in FIG. 1 , the rotary magnetic heater 100 includes a first rotor set 104 and a second rotor set 106. The first rotor set 104 includes a first upper rotor 108 and a vertically spaced first lower rotor 110, defining a gap therebetween. In some cases, as described above, the rotor set includes only the upper rotor. In other cases, the rotor set includes only the lower rotor. The metal strip 102 may be passed through the vertical gap in a direction 124. The first upper rotor 108 may be fixed or may be supported by a first upper rotor support arm 116, which may be operable to move vertically to adjust the vertical gap within the first rotor set 104. The first lower rotor 110 may be supported by a first lower rotor support arm 118, which may be fixed or may be actuable to move vertically to adjust the vertical gap within the first rotor set 104. In some cases, one or both of the first upper rotor support arm 116 and the first lower rotor support arm 118 may be vertically fixed or adjustable. The first rotor set 104 is shown operating in an upstream direction, and the first upper rotor 108 is illustrated rotating in a clockwise direction, while the first lower rotor 110 is illustrated rotating in a counterclockwise direction.

[0058] The second rotor set 106 includes a second upper rotor 112 and a vertically spaced second lower rotor 114, defining a gap therebetween. The metal strip 102 may be passed through the vertical gap in a direction 124. The second upper rotor 112 may be supported by a second upper rotor support arm 120, which may be fixed or operable to move vertically to adjust the vertical gap within the first rotor set 104. The second lower rotor 114 may be supported by a first lower rotor support arm 122, which may be fixed or operable to move vertically to adjust the vertical gap within the second rotor set 104. In some cases, one or both of the second upper rotor support arm 120 and the second lower rotor support arm 122 may be vertically fixed or adjustable. The second rotor set 104 is shown operating in a downstream direction, with the second upper rotor 112 shown rotating in a counterclockwise direction while the second lower rotor 114 is shown rotating in a clockwise direction.

[0059] The rotor sets may be arranged to rotate in any suitable direction. In some cases, the first rotor set 104 may operate in a downstream direction, with the first upper rotor 108 rotating in a counterclockwise direction while the first lower rotor 110 rotates in a clockwise direction. The second rotor set 104 may operate in an upstream direction, with the second upper rotor 112 rotating in a clockwise direction while the second lower rotor 114 rotates in a counterclockwise direction. In some cases, adjacent rotor sets (e.g., the first rotor set 104 and the second rotor set 106) may operate in opposite directions (e.g., upstream and downstream as illustrated in FIG. 1 ) to facilitate counteracting any tension changes induced by one of the rotor sets. In some cases, as described in further detail herein, adjacent rotor sets may operate in the same direction, such as to induce tension changes in the metal strip.

[0060] In some cases, the rotary magnet heater may include additional rotor sets, such as three, four, five, six, seven, eight, or more rotor sets. In other cases, the rotary magnet heater may include only a single rotor set. Each rotor 108, 110, 112, 114 may include one or more magnetic sources. The magnetic sources may be any magnetic source or magnetic flux, such as a permanent magnet or an electromagnet. In some cases, the rotor includes at least one permanent magnet.

[0061] 2 is a top view of a rotary magnet heater 200 according to certain aspects of the present disclosure. The rotary magnet heater 200 may be similar to the rotary magnet heater 100 of FIG. 1, but four rotor sets 204, 206, 226, 228 are shown. A metal strip 202 may pass through the vertical gaps of each of the four rotor sets 204, 206, 226, 228 in a direction 224. As viewed from above, first rotor set 204 may include a first upper rotor 208 supported by a first upper rotor support arm 216 and driven by a first upper rotor motor 238, second rotor set 206 may include a second upper rotor 212 supported by a second upper rotor support arm 220 and driven by a second upper rotor motor 240, third rotor set 226 may include a third upper rotor 230 supported by a third upper rotor support arm 234 and driven by a third upper rotor motor 242, and fourth rotor set 228 may include a fourth upper rotor 232 supported by a fourth upper rotor support arm 236 and driven by a fourth upper rotor motor 244. The lower rotors of each of the rotor sets in FIG. 2 are laterally aligned with their respective upper rotors and are therefore not visible in FIG. 2.

[0062] 3 is an axonometric view of a rotary magnetic heater 300 according to certain aspects of the present disclosure. The rotary magnetic heater 300 may be similar to the rotary magnetic heater 200 of FIG. 2. A first rotor set 304 includes a first upper rotor 308 supported by a first upper rotor support arm 316 and driven by a first upper rotor motor 338, and a first lower rotor 310 supported by a first lower rotor support arm 318 and powered by a first lower rotor motor 350. A second rotor set 306 includes a second upper rotor 312 supported by a second upper rotor support arm 320 and driven by a second upper rotor motor 340, and a second lower rotor 314 supported by a second lower rotor support arm 322 and powered by a second lower rotor motor 352. Third rotor set 326 includes a third upper rotor 330 supported by a third upper rotor support arm 334 and driven by a third upper rotor motor 342, and a third lower rotor 346 supported by a third lower rotor support arm 358 and powered by a third lower rotor motor 354. Fourth rotor set 328 includes a fourth upper rotor 332 supported by a fourth upper rotor support arm 336 and driven by a fourth upper rotor motor 344, and a fourth lower rotor 348 supported by a fourth lower rotor support arm 360 and powered by a fourth lower rotor motor 356.

[0063] Any suitable motive power source may be used in place of the rotor motor. Any suitable motor may be used as the rotor motor. In some cases, the rotor motors may be rotatably coupled to their respective rotors via a belt or chain drive, allowing the rotor motors themselves to be located remotely from their respective rotors. In some cases, a single motor may drive one or more rotors, including one or more rotors of a single rotor set. In some cases, the rotor motor may be coupled to a controller for adjustments to rotor speed. In some cases, the rotor motor is designed to provide a fixed amount of torque, and desired adjustments to the rotor set may be achieved by manipulating the vertical gap between the rotors of the rotor set.

[0064] Each of the rotor support arms 316, 320, 334, 336, 318, 322, 358, 360 may be operable to move the respective rotors 308, 312, 330, 332, 310, 314, 346, 348 in one or more of the following directions: vertical (e.g., up and down), longitudinal (e.g., in direction 224 or opposite direction 224), and lateral (e.g., along a direction parallel to the axis of rotation of the respective rotor). Vertical movement may control the vertical gap between rotors of a single rotor set. Longitudinal movement may control the longitudinal gap between adjacent rotor sets. Lateral movement may control the percentage of the surface of the metal strip 302 covered by a particular rotor and therefore the amount of magnetic flux passing through that portion of the surface of the metal strip 302, as seen in further detail with respect to Figures 5-6.

[0065] FIG. 4 is a cross-sectional side view of a permanent magnet rotor 400 according to certain embodiments of the present disclosure. The magnetic rotor 400 is an example of a rotor suitable for use as rotors 108, 110, 112, and 114 of FIG. 1. The magnetic rotor 400 may include one or more magnetic sources 403. As seen in FIG. 4, the magnetic rotor 400 includes eight magnetic sources 403 that are permanent magnets. The magnets may be arranged in any suitable orientation. The magnetic sources 403 may be arranged so that adjacent permanent magnets face radially outward to provide different poles (e.g., alternating north, south, north, south, north, south, north, south). Any suitable permanent magnet may be used, such as samarium-cobalt, neodymium, or other magnets. In some cases, samarium-cobalt magnets may be more desirable than neodymium magnets because they may decay magnetic field strength more slowly with higher heat. However, in some cases, neodymium magnets may be more desirable than samarium-cobalt magnets because they have stronger magnetic field strength at lower temperatures.

[0066] The magnetic source 403 may be surrounded by a shell 401. The shell 401 may be any suitable material that can allow magnetic flux to pass through. In some cases, the shell 401 may be made of or may further include a non-metallic coating. In some cases, the shell 401 may include a Kevlar® coating.

[0067] In some cases, the magnetic rotor 400 may include a ferromagnetic core 405 having a central axis 407. The magnetic rotor 400 may include other internal arrangements suitable for supporting the magnetic sources 403. While any suitable number of magnetic sources 403 may be used, it has been found that efficient results may be achieved with an even number of magnetic sources 403, specifically six or eight magnetic sources 403.

[0068] The magnetic source 403 may be sized to cover any percentage of the circumference of the magnetic rotor 400. Efficient results may be achieved with a magnetic source 403 sized to occupy approximately 40%-95%, 50%-90%, or 70%-80% of the circumference of the magnetic rotor 400.

[0069] The magnetic rotor 400 may be formed to any suitable size, but it has been found that effective results can be achieved with rotors having diameters of 200 mm to 600 mm, at least 300 mm, at least 400 mm, at least 500 mm, or at least 600 mm.

[0070] The thickness of each magnetic source 403 can be any suitable thickness that can fit within the magnetic rotor 400, but it has been found that effective results can be achieved with permanent magnet thicknesses of 15 mm or at least 15 mm, 15-100 mm, 15-40 mm, 20-40 mm, 25-35 mm, 30 mm, or 50 mm. Other thicknesses may also be used.

[0071] Through trial and experimentation, it has been determined that highly efficient heating power can be obtained by using six or eight magnets arranged around a single rotor, although other numbers of magnets may be used. When too many magnets are used, heating power may be reduced. In some cases, the number of magnets may be selected to minimize installation and / or maintenance costs (e.g., the number of magnets purchased). In some cases, the number of magnets may be selected to minimize tension fluctuations in the metal strip due to the movement of the magnets adjacent to the metal strip. For example, very few magnets may cause larger and / or longer tension fluctuations, whereas more magnets may cause smaller and / or shorter fluctuations. Through trial and experimentation, it has been determined that highly efficient heating power can be obtained when the magnets occupy 40% to 95% of the rotor's circumference, more specifically, 50% to 90%, or 70% to 80% of the rotor's circumference. Through trial and experimentation, it has been determined that highly efficient heating power can be obtained when the rotor diameter is large, such as 200, 300, 400, 500, or 600 mm or more. In addition, the use of larger rotors can help minimize magnet costs. Through trial and experimentation, it has been determined that highly efficient heating power can be obtained when the rotor diameter is large, such as 200, 300, 400, 500, or 600 mm or more. In addition, the use of larger rotors can help minimize magnet costs.

[0072] As rotor speed increases, heating power tends to increase. However, in some cases, when rotor speed reaches a threshold level, further increases in speed will adversely affect heating efficiency due to the inherent inductance and resistivity characteristics of the metal strip. At or about 1800 rpm (e.g., within 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% of 1800 rpm) may be a somewhat desirable speed due to the simplicity of controlling the rotor motor at a 60 Hz frequency found in mains power supplies at various locations. In some cases, other frequencies may be selected based on the rotor motor used and / or the mains power supply provided. While rotor speed can be a useful method for controlling the amount of thermal energy applied to the metal strip, it has been determined that there may be advantages to maintaining a constant rotor speed and using vertical gap control and other controls to adjust the amount of thermal energy applied to the metal strip.

[0073] Through trial and experimentation, it has been determined that highly efficient heating power can be obtained when the thickness of the permanent magnets in the rotor is between 15-40 mm, 20-40 mm, or 25-35 mm, or at or about 30 mm. While stronger heating power can be obtained with thicker magnets, the use of magnets within the above ranges can provide sufficiently strong heating power while simultaneously keeping magnet installation / maintenance costs low.

[0074] Through trial and experimentation, it has been determined that highly efficient heating power can be obtained with metal strip having a thickness of 2 mm or approximately 2 mm (e.g., 1 mm to 4 mm or 1 mm to 3 mm), although metal strips of other sizes may be used. In some cases, heating metal strips having a thickness of 1 mm may provide fast heating, but it may also induce undesirable tension and tension fluctuations in the metal strip. Through trial and experimentation, it has been determined that strip tension can be efficiently controlled when using metal strips having a thickness of 2 mm or approximately 2 mm (e.g., 1 mm to 4 mm or 1 mm to 3 mm).

[0075] FIG. 5 is a top view of a rotary magnet heater 500 with offset rotors, according to certain embodiments of the present disclosure. The rotary magnet heater 500 may be similar to the rotary magnet heater 200 of FIG. 2, but with a third rotor set 526 and a fourth rotor set 528 in an offset configuration. The use of laterally offset rotors, such as in a single rotor set, may facilitate compensation for edge effects. Edge effects are uneven heating of the edges of the metal strip 502, particularly when the rotors extend beyond the edges of the metal strip 502. The degree of offset is exaggerated in FIG. 5 for illustrative purposes.

[0076] The metal strip 502 may pass in a direction 524 through the vertical gaps of each of four rotor sets 504, 506, 526, 528. As viewed from above, the first rotor set 504 includes a first upper rotor 508 supported by a first upper rotor support arm 516 and driven by a first upper rotor motor 538, the second rotor set 506 includes a second upper rotor 512 supported by a second upper rotor support arm 520 and driven by a second upper rotor motor 540, the third rotor set 526 includes a third upper rotor 530 supported by a third upper rotor support arm 534 and driven by a third upper rotor motor 542, and the fourth rotor set 528 includes a fourth upper rotor 532 supported by a fourth upper rotor support arm 536 and driven by a fourth upper rotor motor 544.

[0077] Because the third and fourth rotor sets 526, 528 are in an offset configuration, the third lower rotor 546 and its third lower rotor support arm 558, as well as the fourth lower rotor 548 and its fourth lower rotor motor 556, are visible. The offset configuration may include an upper rotor of a rotor set being laterally offset from the lower rotor of the rotor set. The third upper rotor 530 of the third rotor set 526 appears offset in a first direction, while the third lower rotor 546 is offset in a second direction opposite the first direction. The degree of offset may be defined by lines 562, 564. The distance from line 564 to a first edge of the metal strip 502 (e.g., the edge toward the top of FIG. 5 ) may be the distance at which the rotors 530 and 548 overlap the metal strip 502. The distance from line 562 to the second edge of metal strip 502 (e.g., the edge toward the bottom in FIG. 5 ) can be the distance at which rotors 546 and 532 overlap metal strip 502. The distance between line 562 and line 564 can be the distance at which metal strip 502 overlaps both rotors 530, 546 of third rotor set 526. That distance is also the distance at which metal strip 502 overlaps both rotors 548, 532 of fourth rotor set 528, although in some cases fourth rotor set 528 may have a different overlap distance than third rotor set 526. In use, the rotor overlap distance (e.g., the distance between lines 562, 564) can be at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of the lateral width of metal strip 502. However, the rotor overlap distance may be less than 90% in some cases.

[0078] In some cases, it may be advantageous for the last rotor set of a rotary magnet heater to be in an offset configuration. In one example of a rotary magnet heater having six rotor sets, the last four rotor sets may be in an offset configuration. As seen in Figure 5, rotary magnet heater 500 includes four rotor sets 504, 506, 526, and 528, the last two of which (e.g., rotor sets 526 and 528) are in an offset configuration.

[0079] In some cases, the rotor support arms may adjust the rotor position laterally (e.g., up and down as seen in FIG. 5) to move the rotor in and out of the offset configuration. In some cases, one or more temperature sensors may be used to provide active feedback to control the rotor's position in the offset configuration and therefore the amount of rotor overlap. As the amount of rotor overlap decreases, such as below 100% or 110% of the width of metal strip 502, edge effects may be mitigated.

[0080] 6 is an axonometric view of a rotary magnet heater 600 with offset rotors according to certain embodiments of the present disclosure. The rotary magnet heater 600 may be similar to the rotary magnet heater 500 of FIG. 5. A first rotor set 604 includes a first upper rotor 608 supported by a first upper rotor support arm 616 and driven by a first upper rotor motor 638, and a first lower rotor 610 supported by a first lower rotor support arm 618 and powered by a first lower rotor motor 650. A second rotor set 606 includes a second upper rotor 612 supported by a second upper rotor support arm 620 and driven by a second upper rotor motor 640, and a second lower rotor 614 supported by a second lower rotor support arm 622 and powered by a second lower rotor motor 652. The third rotor set 626 includes a third upper rotor 630 supported by a third upper rotor support arm 634 and driven by a third upper rotor motor 642, and a third lower rotor 646 supported by a third lower rotor support arm 658 and powered by a third lower rotor motor 654. The fourth rotor set 628 includes a fourth upper rotor 632 supported by a fourth upper rotor support arm 636 and driven by a fourth upper rotor motor 644, and a fourth lower rotor 648 supported by a fourth lower rotor support arm 660 and powered by a fourth lower rotor motor 656.

[0081] Similar to that illustrated in FIG. 5, third rotor set 626 and fourth rotor set 628 are shown in an offset configuration.

[0082] 7 is a side view of a rotary magnet heater 700 having a magnetic flux conductor 766, according to certain aspects of the present disclosure. The rotary magnet heater 700 may be similar to the rotary magnet heater 100 of FIG. 1, but has an additional magnetic flux conductor 766 (e.g., a magnetic flux concentrator or magnetic flux guide), which may allow the rotors 708, 710, 712, 714 to be spaced further away from the metal strip 702 than is available for the rotors of FIG. 1. The metal strip 702 passing in the direction 724 may receive magnetic flux directly from the rotors 708, 710, 712, 714 closest to the metal strip 702 (e.g., the magnetic pole located at the edge of the rotor closest to the metal strip), and indirectly through the magnetic flux conductor 766. The flux conductors 766 may direct magnetic flux from magnetic sources within the rotors 708, 710, 712, and 714 that are not oriented toward the metal strip 702, such as magnetic sources directing magnetic flux toward the metal strip 702 in a direction parallel to the direction 724. Furthermore, the presence of the flux conductors 766 around the rotors 708, 710, 712, and 714 allows the first rotor set 704 and the second rotor set 706 to be positioned closer to each other without as much magnetic interference as if the flux conductors 766 were not used. As illustrated in FIG. 1 , each rotor may have four magnetic poles around the circumference of the rotor. The position of the flux conductors 766 may be adjusted to ensure that the magnetic poles do not short-circuit each other through the flux conductors 766. For example, if the rotor contains more than four magnetic poles, the flux conductors 766 may be slightly smaller to avoid undesired short-circuiting of the magnetic flux.

[0083] The magnetic flux conductor 766 may include an iron or iron-based material suitable for focusing, concentrating, or otherwise directing magnetic flux toward the metal strip 702. For example, the magnetic flux conductor 766 may be constructed of silicon alloy steel laminations. In some cases, the magnetic flux conductor 766 may be located on one or both sides (e.g., upstream or downstream of the rotor), along the width of the rotor, adjacent to the rotor. The magnetic flux conductor 766 may be located along the entire width of the rotor, or may be located across or across less than the entire width of the rotor. In some cases, the magnetic flux conductor 766 may be positioned to compensate for edge effects by redirecting magnetic flux adjacent the edges of the metal strip 702. The magnetic flux conductor 766 may be held stationary relative to the rotating rotors 708, 710, 712, 714. In some cases, the magnetic flux conductor 766 may be fixed to the rotor support arms 716, 718, 720, 722 or elsewhere. 7, two flux conductors are shown per rotor. The two flux conductors may correspond to a rotor having two magnetic poles (e.g., two outward-facing poles). The number of flux conductors may be increased to allow for the use of four, six, eight, ten, or more poles per rotor, although any suitable number of flux conductors may be used.

[0084] FIG. 8 is a schematic representation of a continuous casting system 800 utilizing rotary magnetic heaters 868, 869 according to certain embodiments of the present disclosure. A continuous caster 870 may produce a metal product, such as a metal strip 802. The metal strip 802 may optionally pass through heat removal equipment, such as cooling equipment (e.g., water-cooled or air-cooled), ablation equipment, or other such equipment. In some cases, continued transport of the metal strip 802, including contact with ambient air and / or contact with unheated rollers, may reduce the temperature of the metal strip 802. Prior to entering a hot rolling stand 874, the metal strip 802 may be heated by a rotary magnetic heater 868, such as the rotary magnetic heater 100 of FIG. 1 or any other rotary magnetic heater described herein. In some cases, the metal strip 802 may be heated by a rotary magnetic heater 869 after exiting the hot rolling stand 874. In some cases, the metal strip 802 may undergo additional processes after exiting the rotary magnetic heater 869, such as additional hot rolling, cold rolling, or other processes. In the continuous casting system 800, the rotary magnetic heaters 868, 869 may increase or maintain the strip temperature before or after various processes, such as hot rolling. The use of the rotary magnetic heaters 868, 869 may improve the efficiency and speed of metal production in the continuous casting system 800. Any number of the rotary magnetic heaters 868, 869 may be used, and in some cases, only one of the rotary magnetic heaters 868, 869 is used.

[0085] 9 is a schematic representation of a metal processing system 900 using a rotary magnetic heater 968, according to certain embodiments of the present disclosure. The metal processing system 900 includes a rotary magnetic heater 968, such as the rotary magnetic heater 100 of FIG. 1 or any other rotary magnetic heater described herein. The rotary magnetic heater 968 acts on a metal strip 902.

[0086] In some cases, the rotary magnetic heater 968 may be located immediately downstream of one upstream processing facility 976 to maintain or increase the temperature of the metal strip 902 after it exits the upstream processing facility 976 .

[0087] In some cases, the rotary magnetic heater 968 may be located immediately upstream of one downstream processing facility 978 to maintain or increase the temperature of the metal strip 902 before entering the downstream processing facility 978 .

[0088] In some cases, the rotary magnetic heater 968 may be located between one upstream processing facility 976 and one downstream processing facility 978 to maintain or increase the temperature of the metal strip 902 as it travels between the upstream processing facility 976 and the downstream processing facility 978.

[0089] The upstream processing equipment 976 and the downstream processing equipment 978 may be any suitable metal processing equipment, such as part of a CASH line (e.g., a furnace, a cooling unit, or other equipment). The use of the rotary magnetic heater 968 may improve the efficiency and speed of metal production in the metal processing system 900.

[0090] 10 is a schematic representation of a rotary magnet heater control system 1000 according to certain aspects of the present disclosure. The controller 1080 may be any suitable control facility, such as a processor or computer. The controller 1080 may be coupled to various portions of the system 1000 to provide manual or automatic (e.g., programmed and / or dynamic) control of any controllable portion of the system. The controller 1080 may be coupled to the rotor motors 1038 of any number of rotor sets 1004, 1006, vertical gap actuators 1082 (e.g., rotor support arms), longitudinal position actuators 1084, and / or lateral position actuators 1086 to provide appropriate control of the system 1000. The controller 1080 may be coupled to data storage (e.g., non-transitory machine-readable storage) for storing and accessing program information and other data.

[0091] In some cases, the controller 1080 may be coupled to sensors 1088. One or more sensors 1088 may be used to provide feedback to a display for interpretation by a user or may be used to provide dynamic control of one or more portions of the system 1000.

[0092] In one example, the controller 1080 may use a sensor 1088 (e.g., a temperature sensor, a flatness sensor, or a tension sensor) to provide feedback to dynamically adjust the vertical gap of the first rotor set 1004 (e.g., via the vertical gap actuator 1082) to ensure that tension induced by the first rotor set 1004 is compensated for in the second rotor set 1006. When a temperature sensor is used, the controller 1080 may correlate changes in the temperature of the metal strip to adjustments in the vertical gap that are needed to keep the net change in tension on the first rotor set 1004 and the second rotor set 1006 low, near zero, or zero. When a tension sensor is used, the measured tension itself may be used to control the vertical gap so that the net tension on the first rotor set 1004 and the second rotor set 1006 is low, near zero, or zero.

[0093] In some cases, the controller 1080 or a suitable sensor 1088 may monitor power usage associated with the rotor motor 1038. The power usage may provide insight into the operation of the system and may be used by the controller 1080 to make inferences regarding the state of the system. The controller 1080 may then provide feedback to dynamically adjust the system, such as the above (e.g., vertical clearance), based on the sensed power.

[0094] In some cases, the controller 1080 may be coupled to a single rotor rather than a rotor set, in which case the controller 1080 may control any controllable aspect of the rotor, such as rotor speed, lateral position, vertical position, longitudinal position, or other aspect (e.g., magnetic field strength within a rotor with an electromagnetic source).

[0095] In some cases, the controller 1080 may be coupled to an actuator for controlling the position of the metal strip with respect to one or more rotors or rotor sets. For example, the controller 1080 may be coupled to one or more strip deflectors 1092 for controlling the path line of the metal strip. Examples of such strip deflectors 1092 may include one or more of the metal plate 1892 of FIG. 18 , the roller 1992 of FIG. 19 , the spray 2396 of FIG. 32 , and the roller 3298 of FIG. 32 . In some cases, the deflector 1092 may deflect a portion of the metal strip (e.g., less than the full width of the metal strip) toward or away from the magnetic rotor, thus providing a laterally distinct distance between the metal strip and the magnetic rotor.

[0096] In some cases, the controller 1080 may be coupled to one or more of the flux guides 1094 to move or reposition the flux guides 1094 to adjust the amount of magnetic flux passing through all or a portion of the metal strip. Any suitable flux guides, such as those described with reference to Figures 7, 27, 28, and 35-39, may be controllable by the controller 1080.

[0097] 11 is a flowchart illustrating a process 1100 for using a rotary magnet heater according to certain aspects of the present disclosure. At block 1190, a metal strip is passed through a first magnetic rotor set. The metal strip may be passed through a first vertical gap between the first rotor set. At block 1191, the metal strip may be passed through a second magnetic rotor set. The metal strip may be passed through a second vertical gap between the second rotor set.

[0098] In block 1192, the vertical gap of one of the first or second rotor sets may be adjusted. The vertical gap may be increased or decreased as needed to reduce or increase the amount of tension induced in the metal strip by the adjusted rotor set, respectively. For example, if the first rotor set applies an excessively large downstream force that cannot be compensated for by the second rotor set, the vertical gap of the first rotor set may be increased in block 1192, causing the first rotor set to newly apply a smaller downstream force that can be compensated for by the second rotor set. In some cases, block 1192 may be replaced with a block that adjusts a different parameter of the rotor set, such as rotational speed. In some cases, instead of adjusting the vertical gap, the distance adjacent to the rotors may be adjusted, as described in further detail with reference to FIGS. 13-14.

[0099] In optional block 1196, information about the metal strip may be provided to the model. Such information may be information about the type of metal used, the dimensions of the metal strip, the speed of the metal strip, or any other characteristic of the metal strip. By applying this information to the model, the system may be able to determine the vertical clearance required for the first or second rotor set in block 1192.

[0100] In optional block 1194, the system may take measurements of the metal strip, such as temperature measurements or tension measurements. The measurements may be taken by any suitable sensor. The measurements may be used to provide dynamic feedback to adjust the vertical gap in block 1192 based on the measurements. For example, a measurement received in block 1194 of increasing tension in the metal strip may be used in block 1194 to adjust the vertical gap of one of the rotor sets to return the tension to a desired level.

[0101] In optional block 1198, the longitudinal position of at least one rotor set may be adjusted. For example, a first rotor set may be adjusted longitudinally to be closer to or further away from a second rotor set.

[0102] In optional block 1199, the lateral position of at least one rotor of at least one magnetic rotor set may be adjusted. In some cases, the lateral adjustment of one rotor of a magnetic rotor set is accompanied by an equal and opposite lateral adjustment of an opposing rotor of the same rotor set. For example, an upper rotor that is laterally offset in a first direction toward a first edge of the metal strip may be accompanied by a lower rotor of the same rotor set that is laterally offset an equal amount in a second direction toward a second edge of the metal strip. Examples of lateral offsets can be seen with reference to Figures 5-6.

[0103] In optional block 1197, the rotational speed of the rotors of at least one rotor set may be adjusted. The rotational speed may be adjusted to vary the amount of thermal energy imparted onto the moving metal strip. In some cases, the rotational speed of the rotor set may be adjusted to provide control of tension variations between adjacent rotor sets.

[0104] 12 is a side view of a serpentine rotary magnet heater 1200 according to certain aspects of the present disclosure. The serpentine rotary magnet heater 1200 may include multiple rotors 1208, 1210, 1209 within a single rotor set 1204. The serpentine rotary magnet heater 1200 may include moving a metal strip 1202 in a winding, serpentine, or sinusoidal pattern through the rotor set 1204. The extent of the serpentine pattern as seen in FIG. 12 may be exaggerated for illustrative purposes.

[0105] 12, rotor set 1204 includes an upstream rotor 1208, an intermediate rotor 1210, and a downstream rotor 1209. The upstream rotor 1208 and the downstream rotor 1209 are located on the same side (e.g., the top side) of the metal strip 1202, whereas the intermediate rotor 1210 is located on the opposite side (e.g., the bottom side) of the metal strip 1202, thus inducing a serpentine pattern in the metal strip 1202.

[0106] In some cases, heater 1200 may include additional rotor sets. When additional rotor sets are used, adjacent rotor sets may be oriented such that adjacent rotors of adjacent rotor sets are located on opposite sides of the metal strip. For example, the upstream rotor of the rotor set immediately following downstream rotor 1209 may be located on the opposite side of metal strip 1202 from downstream rotor 1209 (e.g., below metal strip 1202 as seen in FIG. 12).

[0107] FIG. 13 is a side view of an extendable rotary magnetic heater 1300 in an extended position, according to certain aspects of the present disclosure. The extendable rotary magnetic heater 1300 may include an idler roller 1321 coupled to an extendable support arm 1323. When in the extended position, as seen in FIG. 13, the extendable support arm 1323 pushes the idler roller 1321 into the cavity 1325. The support roller 1327 may help maintain the proper orientation of the metal strip 1302 and may support the metal strip 1302 away from obstacles (e.g., walls). When in the cavity 1325, the metal strip 1302 may pass through several cavity support rotors 1308 and several central support rotors 1310 (e.g., supported by the extendable support arm 1323). In some cases, the cavity 1325 may include a cavity support rotor 1308 on the opposite side of the idler roller 1321 across the metal strip 1302 when the idler roller 1321 is in the extended position, in which case the idler roller 1321 may be an idler rotor (e.g., an idler roller with an internal rotor) as described in further detail with respect to FIG. 15 .

[0108] The rotors 1308, 1310 may be identical to the rotors described herein with reference to other rotary magnet heaters and may include any and all of the features and / or characteristics thereof, including gap adjustability, longitudinal adjustability, and lateral adjustability. With respect to the extendable rotary magnet heater 1300, the "vertical gap" may include the gap between opposing rotors 1308, 1310 on either side of the metal strip 1302 when the extendable support arm 1323 is in the extended position.

[0109] The extendable rotary magnetic heater 1300 allows a substantial length of metal strip 1302 to be affected by the rotors 1308, 1310 without occupying much longitudinal space in the processing line. The depth of the cavity 1325, and therefore the length of the extendable support arm 1323, may be any suitable size. In some cases, the amount of extension of the extendable support arm 1323 may control the amount of heat imparted to the metal strip 1302, as the amount of extension is directly related to the length of the metal strip exposed to the rotors 1308, 1310, and therefore the amount of time a particular portion of the metal strip is exposed to the rotors 1308, 1310 as it progresses through the extendable rotary magnetic heater 1300.

[0110] 14 is a side view of an extendable rotary magnetic heater 1400 in a retracted position according to certain aspects of the present disclosure. The extendable rotary magnetic heater 1400 may be the extendable rotary magnetic heater 1300 of FIG. 13 in a retracted position. When the extendable support arm 1423 is in the retracted position, the idler roller 1421 may be spaced apart from the metal strip 1402, thus allowing the metal strip to pass through the extendable rotary magnetic heater 1400 without passing through the cavity 1425 and therefore adjacent to the magnetic rotors 1408, 1410. In some cases, the metal strip 1402 may or may not contact the support roller 1427 when the extendable support arm 1423 is in the retracted position.

[0111] 15 is a side view of a serpentine rotary magnet heater 1500 using a combined idler rotor 1531, according to certain aspects of the present disclosure. While any rotary magnet heater can include combined idler rotors 1531, they are particularly useful in the serpentine rotary magnet heater 1500. The serpentine rotary magnet heater 1500 of FIG. 15 includes four idler rotors 1531.

[0112] The combined idler rotor 1531 is an idler roller 1533 with an inner rotor 1510. The inner rotor 1510 can be any suitable rotor, such as those described herein. However, the idler roller 1533 can act as a shell around the inner rotor 1510, against which the metal strip 1502 rests and is supported. The idler roller 1533 can be rotatably disconnected from the inner rotor 1510 or rotatably connected to the inner rotor 1510 so as to rotate at a different speed. This allows the idler roller 1533 to rotate at a speed appropriate to the advancement speed of the metal strip 1502, while the inner rotor 1510 can rotate at a speed appropriate to the desired changing magnetic field. One or more opposing rotors 1508 can be located on opposite sides of the idler rotor 1531 across the metal strip 1502.

[0113] In some cases, the distance between the magnetic source within the idler rotor 1531 (e.g., inner rotor 1510) and the surface of the idler rotor 1531 (e.g., idler roller 1533) may be fixed. In such cases, any adjustment of the vertical gap may be due solely to adjustment of the opposing rotor 1508. However, in some cases, the strength of the magnetic field from the idler rotor 1531 may be controlled by inserting a magnetically translucent or magnetically opaque material into the idler rotor 1531 between the magnetic source of the idler roller 1533 and the inner rotor 1510.

[0114] 16 is a side view of a rotary magnet heater 1600 with longitudinal gap control, according to certain embodiments of the present disclosure. The rotary magnet heater 1600 may be similar to the rotary magnet heater 100 of FIG. 1, except that a first rotor set 1604 and a second rotor set 1606 are mounted on a longitudinal track 1651. Longitudinal gap control may be achieved in many different ways, such as through individual control of the rotor support arms, but one such way may include mounting the rotor support arms on the longitudinal track 1651 and manipulating the support arms along the longitudinal track 1651 using a linear actuator (e.g., a belt drive, screw actuator, or other actuator).

[0115] Through trial and experimentation, it has been determined that strip tension itself cannot be controlled through adjustment of the longitudinal gap (e.g., horizontal gap) between adjacent rotor sets (e.g., the longitudinal gap between the first rotor set 1604 and the second rotor set 1606). However, strip tension variation can be controlled through gap adjustment. Through trial and experimentation, it has been determined that highly efficient tension variation control can be achieved using 400 mm rotors spaced 250 mm apart. In some cases, the first and second rotor sets and the third and fourth rotor sets can be spaced 250 mm apart, while the second and third rotor sets can be spaced 500 mm apart. In some cases, the second and third rotor sets can be positioned to have a longitudinal gap that is twice as wide as the longitudinal gap between the first and second rotor sets and the third and fourth rotor sets.

[0116] Through trial and experimentation, it has been determined that tension fluctuations can be controlled by ensuring that the longitudinal gap between adjacent rotors is far enough apart so that magnetic interaction between adjacent rotors does not induce undesired tension fluctuations. It may be advantageous to position adjacent rotor sets with a longitudinal gap of 50 mm, 100 mm, 200 mm, 300 mm, 400 mm, or 500 mm or more. In some cases, when flux diverters are used, the longitudinal gap distance can be reduced while maintaining effective tension control.

[0117] FIG. 17 is a side view of a rotary magnetic heater 1700 having a rotor set with a single rotor, according to certain embodiments of the present disclosure. The rotary magnetic heater 1700 can include any number of rotors 1710, 1712 and rotor sets 1704, 1706. The rotors 1710, 1712 can be similar to the rotors 110, 112 of FIG. 1. As seen in FIG. 17, the rotary magnetic heater 1700 includes a first rotor set 1704 and a second rotor set 1706, each having a single rotor. The first rotor set 1704 includes a single lower rotor 1710 adjacent to which the metal strip 1702 can pass in a direction 1724. The lower rotor 1710 can be fixed or can be supported by a lower rotor support arm 1718, which can be actuated to move vertically to adjust the distance between the lower rotor 1710 and the metal strip 1702. In some cases, the lower rotor support arm 1718 may be vertically fixed or adjustable. The first rotor set 1704 is shown operating in a downstream direction, and the lower rotor 1710 is shown rotating in a clockwise direction.

[0118] The second rotor set 1706 includes an upper rotor 1712 adjacent to which the metal strip 1702 may pass in a direction 1724. The upper rotor 1712 may be supported by an upper rotor support arm 1720, which may be fixed or may be actuable to move vertically to adjust the distance between the upper rotor 1712 and the metal strip 1702. In some cases, the upper rotor support arm 1720 may be vertically fixed or adjustable. The second rotor set 1704 is shown operating in an upstream direction, and the upper rotor 1712 is shown rotating in a clockwise direction.

[0119] The rotors 1710, 1712 may operate without any directly opposing rotors located on opposite sides of the metal sheet. In some cases, adjacent rotor sets 1704, 1706, each having a single rotor, may be arranged so that adjacent rotors are located on opposite sides of the metal strip 1702, but this is not required. In some cases, additional equipment, such as support rollers, gas nozzles (e.g., air nozzles), or other such equipment, may be used to counteract any forces induced by the rotors 1710, 1712 that move the metal strip 1702 away from the desired path line. For example, the single rotor 1710, 1712 may slightly pull the metal strip 1702 toward the rotors 1710, 1712. Such a pulling force may be counteracted by gravity, support rollers, or any other applied force (e.g., via a gas nozzle). In some cases, no counteracting force is applied.

[0120] 18 is a side view of a rotary magnetic heater 1800 having a rotor set with a single rotor facing metal plates 1892, 1894, according to certain embodiments of the present disclosure. The rotary magnetic heater 1800 may include any number of rotors 1808, 1812 and rotor sets 1804, 1806. The rotors 1808, 1812 may be similar to the rotors 110, 112 of FIG. 1. As seen in FIG. 18, the rotary magnetic heater 1800 includes a first rotor set 1804 and a second rotor set 1806, each having a single rotor and facing metal plates. The first rotor set 1804 includes a single upper rotor 1808 adjacent to which the metal strip 1802 may pass in a direction 1824. The upper rotor 1808 may be supported by an upper rotor support arm 1816, which may be fixed or may be actuable to move vertically to adjust the distance between the upper rotor 1808 and the metal strip 1802. In some cases, the upper rotor support arm 1816 may be vertically fixed or adjustable. The first rotor set 1804 is shown operating in the downstream direction, and the upper rotor 1808 is shown rotating in a counterclockwise direction.

[0121] The second rotor set 1806 includes an upper rotor 1812 adjacent to which the metal strip 1802 may pass in a direction 1824. The upper rotor 1812 may be supported by an upper rotor support arm 1820, which may be fixed or may be actuable to move vertically to adjust the distance between the upper rotor 1812 and the metal strip 1802. In some cases, the upper rotor support arm 1820 may be vertically fixed or adjustable. The second rotor set 1804 is shown operating in an upstream direction, and the upper rotor 1812 is shown rotating in a clockwise direction.

[0122] The rotors 1808, 1812 may not include any directly opposing rotors, but may operate with opposing metal plates 1892, 1894 located on the opposite side of the rotors 1808, 1812 across a metal sheet. The metal plates 1892, 1894 may or may not contact the metal strip 1802. The metal plates 1892, 1894 may be made of a metal, such as a ferrous or non-ferrous metal. In some cases, the metal plates 1892, 1894 may be made of steel. The use of the metal plates 1892, 1894 may help direct and / or concentrate the magnetic field from the rotors 1808, 1812 through the metal strip 1802. The metal plates 1892, 1894 may be held stationary. In some cases, the metal plates 1892, 1894 may be vertically actuable to adjust the distance between the metal plates 1892, 1894 and the metal strip 1802. In some cases, the metal plates 1892, 1894 may be coated with a protective layer such as Kevlar. In some cases, the rotary magnetic heater 1800 does not include the metal plates 1892, 1894.

[0123] FIG. 19 is a side view of a rotary magnetic heater 1900 having a rotor set of a single rotor opposed to rollers 1992, 1994, according to certain embodiments of the present disclosure. The rotary magnetic heater 1900 may include any number of rotors 1908, 1912 and rotor sets 1904, 1906. The rotors 1908, 1912 may be similar to the rotors 110, 112 of FIG. 1. As seen in FIG. 19, the rotary magnetic heater 1900 includes a first rotor set 1904 and a second rotor set 1906, each having a single rotor and opposed rollers. The first rotor set 1904 includes a single upper rotor 1908 adjacent to which the metal strip 1902 may pass in a direction 1924. The upper rotor 1908 may be fixed or may be supported by an upper rotor support arm 1916, which may be operable to move vertically to adjust the distance between the upper rotor 1908 and the metal strip 1902. In some cases, the upper rotor support arm 1916 may be vertically fixed or adjustable. The first rotor set 1904 is shown operating in a downstream direction, and the upper rotor 1908 is shown rotating in a counterclockwise direction.

[0124] The second rotor set 1906 includes an upper rotor 1912 adjacent to which the metal strip 1902 may pass in a direction 1924. The upper rotor 1912 may be supported by an upper rotor support arm 1920, which may be fixed or may be actuable to move vertically to adjust the distance between the upper rotor 1912 and the metal strip 1902. In some cases, the upper rotor support arm 1920 may be vertically fixed or adjustable. The second rotor set 1904 is shown operating in an upstream direction, and the upper rotor 1912 is shown rotating in a clockwise direction.

[0125] The rotors 1908, 1912 do not include any directly opposing rotors located on the opposite side of the metal sheet from the rotors 1908, 1912, and may operate with opposing rollers 1992, 1994. The rollers 1992, 1994 may or may not contact the metal strip 1902. The rollers 1992, 1994 may be made of a metal, such as a ferrous or non-ferrous metal. In some cases, the rollers 1992, 1994 may be made of steel. The use of the rollers 1992, 1994 may help direct and / or concentrate the magnetic field from the rotors 1908, 1912 through the metal strip 1902, optionally providing support to the metal strip 1902. The rollers 1992, 1994 may rotate freely or may be driven to rotate (e.g., by a motor). In some cases, the rollers 1992, 1994 may be vertically actuable to adjust the distance between the rollers 1992, 1994 and the metal strip 1902. In some cases, the rollers 1992, 1994 may be coated with a protective layer such as Kevlar®.

[0126] FIG. 20 is a side view of a rotary magnetic heater 2000 that is movable relative to a stationary metal strip 2002, according to certain aspects of the present disclosure. The rotary magnetic heater 2000 may include any number of rotors 2008, 2010 and rotor set 2004. The rotors 2008, 2010 may be similar to the rotors 108, 110 of FIG. 1. As seen in FIG. 20, the rotary magnetic heater 2000 includes a first rotor set 2004 having an upper rotor 2008 and a lower rotor 2010. Other configurations may be used. The metal strip 2002 may be positioned adjacent to the rotors 2008, 2010, such as in the vertical gap between the rotors 2008, 2010. The metal strip 2002 may be held stationary (e.g., stationary relative to the ground), as indicated by the canceled directional arrow. To achieve the desired heating effect, rotor set 2004 may move longitudinally relative to metal strip 2002, such as in direction 2025. In some cases, rotor support arms 2016, 2018 may be movably coupled to track 2051. Movement along track 2051 allows rotors 2008, 2010 to move longitudinally relative to metal strip 2002, achieving the same relative motion, and therefore the overall heating effect, as shown in FIG. 1 as metal strip 2002 moves and rotors 2008, 2010 move. Rotors 2008, 2010 may continue to rotate as they are translated longitudinally up and down the length of metal strip 2002 (e.g., in a downstream direction as illustrated in FIG. 20). In some cases, other metal pieces, parts, or products, such as metal sheets, metal shafts, metal plates, formed parts, etc., may be used in place of stationary metal strip 2002.

[0127] Figure 21 is an axonometric view of a rotary magnet heater 2100 having multiple sub-rotors 2109, according to certain aspects of the present disclosure. The rotary magnet heater 2100 may be similar to the rotary magnet heater 200 of Figure 2. The rotor set 2104 may include an upper rotor 2108 supported by an upper rotor support arm 2116 and driven by an upper rotor motor 2138, and a lower rotor 2110 supported by a lower rotor support arm 2118 and powered by a lower rotor motor 2150. Although the rotors 2108, 2110 of Figure 21 are shown without outer covers, outer covers may be used over some or all of the sub-rotors 2109.

[0128] Each rotor 2108, 2110 may include two or more sub-rotors 2109. Each sub-rotor 2109 may occupy less than 100% of the width of the rotor in which it is included. As illustrated in FIG. 21 , the rotors 2108, 2110 each include eleven sub-rotors 2109. Each sub-rotor 2109 may provide a distinct amount of magnetic flux (e.g., a varying magnetic field) to the metal strip 2102 in a distinct area (e.g., at or around the sub-rotor 2109). Each sub-rotor 2109 may be driven individually (e.g., via an individual motor) or co-driven with one or more other sub-rotors 2109 (e.g., multiple sub-rotors 2109 sharing a single motor). A rotor motor or other motive force providing device may be used to rotate the sub-rotors 2109. In some cases, an individual sub-rotor 2109 may be configured to rotate at a different speed than the other sub-rotors 2109. For example, sub-rotors 2109 located longitudinally above and below a conventional "cold" spot on the surface of the metal strip 2102 (e.g., slightly inboard from the edge of the metal strip) may be driven faster than adjacent sub-rotors 2109, allowing that location to heat more than adjacent locations, thus inducing a more uniform or more homogeneous temperature profile across the width of the metal strip. In some cases, the sub-rotors 2109 may be preset to rotate at a constant relative speed with respect to one another, such as through the use of gears or gear systems. In some cases, a transmission may be used to manually or automatically vary the relative speed of one sub-rotor 2109 with respect to another.

[0129] 22 is a top view of a rotary magnetic heater 2200 having multiple sub-rotors 2209, according to certain aspects of the present disclosure. The rotary magnetic heater 2200 may include a rotor 2208. The rotor 2208 may be similar to the rotor 2108 of FIG. 21. The metal strip 2202 may pass under the rotor 2208 in a direction 2224 and therefore under the sub-rotors 2209.

[0130] FIG. 23 is a chart illustrating rotor speed 2309 and strip temperature 2301 of rotor 2208 and metal strip 2202 of FIG. 22 under a first condition, according to certain embodiments of the present disclosure. Line 2309 illustrates the dimensionless rotor speed for each of the eleven sub-rotors 2209 of FIG. 22. For convenience, the chart of FIG. 23 is vertically aligned with the sub-rotors 2209 of FIG. 22. Dashed line 2302 indicates the edge of metal strip 2202. Line 2301 illustrates the dimensionless strip temperature across the width of metal strip 2202 at or shortly after it passes rotor 2208. Lines 2309, 2301 are not necessarily drawn to scale and are shown exaggerated for illustrative purposes.

[0131] Under a first condition, each of the sub-rotors 2209 is driven at the same speed and generates a moving magnetic field similar to or identical to a single full-length rotor. The resulting strip temperature 2301 from such a moving magnetic field exhibits a profile with "hot" spots at the edges of the metal strip 2202 and "cool" spots slightly proximal to the edges of the metal strip 2202 (e.g., just in from the edges of the metal strip 2202). These hot and cool spots may be the result of edge effects when the magnetic field and the induced electric field interact at the edges of the metal strip 2202. This uneven temperature distribution may be undesirable.

[0132] FIG. 24 is a chart illustrating rotor speed 2409 and strip temperature 2401 of rotor 2208 and metal strip 2202 of FIG. 22 under a second condition, according to certain embodiments of the present disclosure. Line 2409 illustrates the dimensionless rotor speed for each of the eleven sub-rotors 2209 of FIG. 22. For convenience, the chart of FIG. 24 is vertically aligned with the sub-rotors 2209 of FIG. 22. Dashed line 2402 indicates the edge of metal strip 2202. Line 2401 illustrates the dimensionless strip temperature across the width of metal strip 2202 at or shortly after it passes rotor 2208. Lines 2409, 2401 are not necessarily drawn to scale and are shown exaggerated for illustrative purposes.

[0133] Under the second condition, each of the sub-rotors 2209 is driven at the same speed except for the penultimate sub-rotor 2209 adjacent the end of the rotor 2208. The penultimate sub-rotor 2209 is shown driven at a faster speed than the remaining sub-rotors 2209. This condition generates a moving magnetic field similar to that of a single full-length rotor, except near or slightly inside the edge of the metal strip 2202, where heating is increased. The resulting strip temperature 2401 from this moving magnetic field exhibits a profile that is more uniform across the width of the metal strip 2202 than the strip temperature 2301 for the first condition shown in FIG. 23. Therefore, by adjusting the speed of a particular sub-rotor 2209 within the rotor 2208, the temperature uniformity across the width of the metal strip 2202 can be improved.

[0134] In some cases, the strip temperature 2401 may be considered a uniform temperature profile. In some cases, other techniques, such as those disclosed herein, may be used to achieve a uniform temperature profile. A uniform temperature profile may include a temperature profile across the metal article that varies by no more than 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, or 25°C from the average temperature. In some cases, other variations may be used. In some cases, the variation may be no more than 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, or 10°C from the average temperature.

[0135] FIG. 25 is a front view of a rotor 2508 illustrating a magnetic flux profile 2509, according to certain embodiments of the present disclosure. As disclosed herein, various techniques can allow different amounts of magnetic flux to pass through a metal strip traveling adjacent to the magnetic rotor. One technique for controlling the amount of heat introduced across the width of the metal strip is to provide a rotor 2508 with a tailored magnetic flux profile 2509. The tailored magnetic flux profile 2509 can be designed to impart a desired amount of heating to the metal strip when the rotor 2508 is rotated adjacent to the moving metal strip. The rotor 2508 can be any of the rotors described herein, such as the rotor 108 of FIG. 1. Various techniques can provide the tailored magnetic flux profile 2509, as described in further detail herein. In some cases, it may be desirable to provide increased magnetic flux immediately near the edges of the metal strip to reduce the incidence of cool spots, such as those illustrated in FIG. 23. In some cases, other magnetic flux profiles 2509 may be desired to improve temperature control, provide greater flexibility in temperature control, or for other reasons.

[0136] In some cases, the adjusted magnetic flux profile 2509 of the rotor 2508 may be static and not dynamically adjustable. In such cases, the rotor 2508 may need to be stopped (e.g., stopped from rotating) and optionally removed to adjust the magnetic flux profile 2509. In some cases, the rotor 2508 may have an adjusted magnetic flux profile 2509 that is static and established using a desired permanent magnet array, such as a Halbach array. In some cases, the magnetic flux profile 2509 may be dynamically adjusted, for example, according to a predetermined program or in response to feedback (e.g., signals from a temperature sensor, a flatness sensor, a power sensor, or other such sensor). The magnetic flux profile 2509 may be dynamically adjusted according to any suitable technique, such as by adjusting the rotational speed of the sub-rotor, by adjusting an actuator to move some of the rotor's magnets closer to or away from the metal strip (e.g., closer to or away from the outer shell of the rotor), by adjusting an actuator to move magnetic flux concentrators in or around the rotor, etc.

[0137] Similarly, in some cases, the position and / or orientation of the rotor may be controlled to adjust the magnetic flux profile passing through the metal strip. In such cases, the magnetic flux profile 2509 of the rotor 2508 itself may not change dynamically, but the profile of the magnetic flux passing through the metal strip may be dynamically adjusted.

[0138] The tuned magnetic flux profile 2509 of the rotor 2508 illustrated in Figure 25 includes triangular shaped profile elements. In some cases, the profile elements may take other shapes, such as square, circular, oval, sawtooth, or any other suitable shape.

[0139] FIG. 26 is a front perspective view illustrating a rotor 2608 having a contoured magnetic rotor 2603 within a shell 2601, according to certain embodiments of the present disclosure. The rotor 2608 is an example of how the tailored magnetic flux profile 2509 of FIG. 25 can be achieved. The rotor 2608 includes an outer shell 2601 exhibiting a cylindrical outer surface. Within the shell 2601, the contoured magnetic rotor 2603 has a contour that can achieve the desired tailored magnetic flux profile 2609. The contoured magnetic rotor 2603 can include several magnets arranged around the periphery of the magnetic rotor 2603. In areas where more magnetic flux is desired, the diameter of the magnetic rotor 2603 can be larger, whereas locations where the diameter of the magnetic rotor 2603 is smaller can result in less magnetic flux near those locations.

[0140] FIG. 27 is a front perspective view illustrating a rotor 2708 having a magnetic flux concentrator 2766, according to certain embodiments of the present disclosure. The rotor 2708 is an example of how the tailored magnetic flux profile 2509 of FIG. 25 can be achieved. The rotor 2708 includes an outer shell 2701 having a magnetic flux concentrator 2766 coupled thereto or incorporated thereon. Within the shell 2701, a magnetic rotor 2703 typically has a flat profile that outputs a flat magnetic flux profile. Due to the presence of the magnetic flux concentrator 2766, the magnetic flux profile 2709 of the rotor 2708 exhibits a tailored profile similar to the tailored magnetic flux profile 2509 of FIG. 25. In some cases, dynamic adjustment of the rotor's magnetic flux profile 2709 can be achieved through dynamic manipulation of the magnetic flux concentrator 2766. In some cases, magnetic flux concentrator 2766 may be located within shell 2701, such as between shell 3081 and magnetic rotor 2703. Magnetic flux concentrator 2766 may be any material suitable for concentrating magnetic flux, such as magnetic steel (e.g., laminated steel).

[0141] 28 is a cross-sectional side view of a permanent magnet rotor 2800 having a magnetic flux concentrator 2866, according to certain aspects of the disclosure. The magnetic rotor 2800 may be the rotor 2708 of FIG. 27 or any other suitable rotor, such as rotors 108, 110, 112, 114 of FIG. 1. The magnetic rotor 2800 may include one or more magnetic sources 2803, such as permanent magnets. The magnetic rotor 2800 of FIG. 28 may be similar to the magnetic rotor 400 of FIG. 4, but with an additional magnetic flux concentrator 2866.

[0142] The magnetic source 2803 may be surrounded by a shell 2801. The shell 2801 may be any suitable material that can allow magnetic flux to pass through. In some cases, the shell 2801 may be made of or may further include a non-metallic coating. In some cases, the shell 2801 may include a Kevlar® coating.

[0143] In some cases, the magnetic rotor 2800 may include a ferromagnetic core 2805 having a central axis 2807. In some cases, the magnetic rotor 2800 may include other internal arrangements suitable for supporting the magnetic sources 2803. Any suitable number of magnetic sources 2803 may be used.

[0144] In some cases, the magnetic flux concentrator 2866 may be coupled to the shell 2801 or otherwise incorporated into the surface of the shell 2801. In some cases, the magnetic flux concentrator may be located within the shell 2801, allowing the outer surface of the rotor to remain substantially cylindrical. The magnetic flux concentrator 2866 may be positioned on an outward-facing edge (e.g., a radially outward-facing edge) of the magnetic source 2803. The magnetic flux may be improved wherever the magnetic flux concentrator 2866 is present relative to where the magnetic flux concentrator 2866 is not present. Therefore, the rotor 2800 may be constructed with magnetic flux concentrators 2866 in some lateral locations along the width of the rotor 2800 (e.g., in and out of the plane of the paper as seen in FIG. 28 ) but not in other locations. Thus, a tailored magnetic flux profile may be achieved across the width of the rotor 2800.

[0145] 29 is a front view illustrating a rotor set 2900 including variable flux rotors 2908, 2910, according to certain aspects of the present disclosure. As illustrated in FIG. 29, the contours of the rotors 2908, 2910 are contoured to represent a contoured magnetic flux profile for the rotors 2908, 2910 (e.g., a vase-like contour or a bowling pin-like contour). The actual outer surfaces of the rotors 2908, 2910 may be contoured, cylindrical, or other shapes. As disclosed herein, the tailored magnetic flux profile may be established using various techniques regardless of the shape of the outer shell of the rotors 2908, 2910.

[0146] The rotors 2908, 2910 specifically assume a continuously variable magnetic flux profile. This particular profile may be known as a continuously variable crown profile. This particular profile, and other similar profiles, may be used to provide improved adjustability over the amount of magnetic flux passing through the magnetic strip 2902. By adjusting the position and / or orientation of the rotors 2908, 2910, different magnetic field profiles may be presented to the metal strip 2902. For example, moving the position of one or more of the rotors 2908, 2910 laterally (e.g., left and right as seen in FIG. 29) or vertically (e.g., up and down as seen in FIG. 29) may provide a degree of control over the magnetic flux passing through the metal strip 2902. Additionally, rotation of one or more of the rotors 2908, 2910 about a longitudinal axis (e.g., about the longitudinal axis of the metal strip, or clockwise or counterclockwise as seen in FIG. 29) or about a vertical axis (e.g., about an axis parallel to the plane of the page and extending from the bottom to the top of the page, as seen in FIG. 29) may provide even greater control over the magnetic flux passing through the metal strip 2902. Finally, coordinated adjustment of the upper rotor 2908 and lower rotor 2910 relative to each other and to the metal strip 2902 may provide even greater control over the magnetic flux passing through the metal strip 2902.

[0147] 30 is a front view illustrating the rotor set 2900 of FIG. 29 after repositioning of the variable flux rotors 2908, 2910, in accordance with certain aspects of the present disclosure. In FIG. 30, the upper rotor 2908 has been moved in a first direction and the lower rotor 2910 has been moved in the opposite direction. As a result, the portions of the rotors 2908, 2910 with higher magnetic flux are positioned more directly above the metal strip 2902, resulting in increased heat input to the metal strip 2902 near the edge of the metal strip 2902.

[0148] FIG. 31 is a front view illustrating a rotor set 3100 including flared flux rotors 3108, 3110, according to certain aspects of the present disclosure. As illustrated in FIG. 31 , the contours of the rotors 3108, 3110 are flared (e.g., horn-like) to represent the flared flux profile of the rotors 3108, 3110. The actual outer surfaces of the rotors 3108, 3110 may be flared, cylindrical, or other shapes. As disclosed herein, the tailored flux profile may be established using various techniques regardless of the shape of the outer shell of the rotors 3108, 3110.

[0149] The flared shape of the magnetic flux profile of the rotors 3108, 3110 can be particularly useful for adjusting the amount of heating that occurs near the edges of the metal strip 3102. By adjusting the position of the rotors 3108, 3110 relative to each other and laterally relative to the metal strip 3102 (e.g., side to side as seen in FIG. 31 ), the strength of the magnetic flux passing through the metal strip can be increased near the edges of the metal strip 3102 without increasing the amount of magnetic flux passing through the center of the metal strip.

[0150] FIG. 32 is a front view illustrating a technique for adjusting the amount of magnetic flux passing through the metal strip 3202, according to certain aspects of the present disclosure. As illustrated in FIG. 32, the contour of the rotor 3208 is linear (e.g., cylindrical) to represent the linear magnetic flux profile of the rotor 3208. However, the technique illustrated in FIG. 32 may also be used with a rotor 3208 having a non-linear (e.g., contoured) magnetic flux profile. The actual outer surfaces of the rotors 3208, 3210 may be contoured, cylindrical, or other shapes. As disclosed herein, a tailored magnetic flux profile through the metal strip 3202 can be established using various techniques independent of the magnetic flux profile of the rotor 3208. By applying an external force to the metal strip 3202, the metal strip 3202 can be urged toward the rotor 3208 at certain locations (e.g., the edges of the strip 3202 in FIG. 32) and remain away from the rotor 3208 at other locations (e.g., the center of the strip 3202 in FIG. 32). Thus, the portion of the metal strip 3202 closest to the rotor 3208 may be supplied with the strongest magnetic flux. Any suitable technique may be used to apply a force to urge the metal strip 3202 toward the rotor 3208. In one example, a spray 3296 of fluid, such as a gas (e.g., air), may be supplied to the metal strip 3202 on the opposite side of the rotor 3208 where increased magnetic flux is desired. This fluid spray 3296 may urge the metal strip 3202 toward the rotor 3208. In another example, a roller or roller set 3298 may be positioned on the opposite side of the metal strip 3202 from the rotor 3208 where increased magnetic flux is desired. This roller or roller set 3298 may urge the metal strip 3202 toward the rotor 3208. Other suitable techniques may be used to selectively urge portions of the metal strip 3202 toward the rotor 3208.

[0151] Figure 33 is a top view of a rotary magnet heater 3300 according to certain embodiments of the present disclosure. The rotary magnet heater 3300 may be similar to the rotary magnet heater 100 of Figure 1 or the rotary magnet heater 200 of Figure 2, but with additional heating elements 3391, 3393, 3396 (e.g., auxiliary heating elements). The rotary magnet heater 3300 of Figure 33 may utilize the additional heating elements 3391, 3393, 3396 to even out any cool spots in the metal strip 3302 after heating using the rotors 3308, 3312. Any number of additional heating elements 3391, 3393, 3396 may be used, such as one, two (e.g., a pair of elements positioned symmetrically about the centerline of the lateral width of the metal strip 3302), or three or more.

[0152] As the metal strip 3302 passes through the rotors 3308, 3312 in the direction 3324, the metal strip 3302 may heat up. Depending on the magnetic flux passing through the metal strip 3302, the metal strip may exit the rotors 3308, 3312 with a temperature profile 3395 containing cold spots (e.g., localized areas of low temperature). In some cases, these cold spots may be mitigated by adding extra heating using additional heating elements 3391, 3393, 3396. The additional heating element 3391 may represent any suitable heating element, such as a rotating magnet, hot air, heated fluid, electrical resistance, direct thermal shock, infrared heating, induction heating, or other such element capable of applying localized heat to the metal strip 3302 at or near the cool spot. As shown in FIG. 33, the additional heating element 3391 is positioned downstream of the rotors 3308, 3312, however this is not necessarily the case; the additional heating element 3391 may instead be positioned upstream of the rotors 3308, 3312 to preheat areas of the metal strip 3302 that would otherwise result in cool spots.

[0153] The additional heating element 3393 is an example of a rotating magnet that includes multiple magnetic poles on a disk that rotates about an axis perpendicular to the surface of the metal strip. This rotation induces heating in the metal strip 3302 around targeted locations, such as where cool spots exist or are expected to exist.

[0154] Additional heating element 3396 is an example of a rotating magnet (e.g., a magnetic rotor) that rotates about an axis of rotation that is parallel to direction 3324 (e.g., the downstream direction) and perpendicular to the width of metal strip 3302. In some cases, additional heating element 3391 can be a rotating magnet (e.g., a magnetic rotor) that rotates about an axis of rotation that is parallel to rotors 3308, 3312 (e.g., perpendicular to direction 3324 and parallel to the width of metal strip 3302).

[0155] After passing through both the rotors 3308, 3312 and any additional heating elements 3391, 3393, 3396, the metal strip 3302 may have a temperature profile 3397 that is uniform, nearly uniform, or more uniform than the temperature profile 3395.

[0156] In some cases, cold spots occur near, but not at, the edges of the metal strip 3302. This location may be common due to the path that eddy currents must take within the metal strip 3302 as they approach an edge, resulting in a localized cold spot a short distance away from the edge with a localized hot spot at the edge. In some cases, additional heating elements 3391, 3393, 3396 may be positioned proximate to and between the metal strip 3302 at lateral locations between the edges of the metal strip 3302 and the lateral centerline of the metal strip 3302. In some cases, the additional heating elements 3391, 3393, 3396 may be positioned adjacent to the metal strip at a lateral location that is laterally spaced from the edge of the metal strip (e.g., toward the lateral centerline of the metal strip) by a distance of approximately 5% to 25%, 7% to 20%, 8% to 15%, 9%, 10%, 11%, 12%, 13%, or 14% of the width of the metal strip 3302.

[0157] 34 is a combined schematic and graph illustrating a magnetic heating and tension control system 3400 according to certain embodiments of the present disclosure. The system 3400 may include multiple rotors 3408, 3410 capable of heating and inducing tension changes in a metal strip 3402. The magnetic heating and tension control system 3400 may be used with any suitable metal processing equipment, such as a coil unwinder or coil rewinder, as illustrated in FIG.

[0158] The left portion of FIG. 34 illustrates a rotor 3408 positioned immediately downstream of the coil unwinder. As the metal strip 3402 unwinds from the coil, tension may initially be relatively high, as seen by tension line 3409 in FIG. 34. By rotating each of the rotors 3408 in an upstream direction, the rotors 3408 may increase the temperature of the metal strip 3402 while providing tension adjustment, as seen by temperature line 3401 in FIG. 34. Each successive rotor 3408 operating in an upstream direction following the coil unwinder may decrease the tension in the metal strip while increasing its temperature. This technique may be particularly beneficial because as the temperature of the metal strip 3402 increases, excessive tension and / or physical contact may be undesirable and may result in defects in the metal strip 3402. The use of the magnetic rotor 3408 to increase the temperature and reduce tension in the metal strip 3402 can be achieved without physical contact between the metal strip 3402 and the rotor 3408.

[0159] The right portion of FIG. 34 illustrates a rotor 3410 positioned immediately upstream of a coil rewinder. As the metal strip 3402 is directed toward the coil rewinder, tension may initially be relatively low and may need to be increased before the metal strip 3402 is wound into a coil. Furthermore, it may be desirable to increase the temperature of the metal strip 3402 immediately before rewinding, especially if the metal strip 3402 has previously been quenched to a low temperature. Therefore, the magnetic rotor 3410 described herein may be particularly useful for both increasing the temperature of the metal strip 3402 and increasing the tension in the metal strip 3402 without having to contact the metal strip 3402. By rotating the magnetic rotor 3410 in a downstream direction, the rotor 3410 may increase the temperature of the metal strip 3402 while simultaneously increasing the tension in the metal strip 3402.

[0160] FIG. 35 is a front view of a rotor 3508 having a pair of rotor sleeves 3592 that provide a magnetic flux profile 3509, according to certain aspects of the present disclosure. As disclosed herein, various techniques can allow different amounts of magnetic flux to pass through a metal strip traveling adjacent to the magnetic rotor. One technique for controlling the amount of heat introduced across the width of the metal strip is to provide a rotor 3508 with a tailored magnetic flux profile 3509. The tailored magnetic flux profile 3509 can be designed to impart a desired amount of heating to the metal strip when the rotor 3508 is rotated adjacent to the moving metal strip. The rotor 3508 can be any of the rotors described herein, such as the rotor 108 of FIG. 1.

[0161] 35, tailored magnetic flux profiles 3509 can be produced by using rotor sleeves 3592 positioned on or around the magnetic rotor 3508 at various locations. The rotor sleeves 3592 can be designed to shunt and / or focus the magnetic flux, thus producing a magnetic flux profile 3509 that would be similar to a magnetic rotor having a varying width, without actually having to change the width of the rotor. The sleeves 3592 can be made of any suitable material for shunting and / or focusing the magnetic flux, such as, for example, a ferromagnetic material (e.g., steel).

[0162] The sleeve 3592 may extend the entire width of the rotor 3508, or less than the entire width of the rotor 3508. As shown, a two-sleeve configuration is used to provide a magnetic flux profile 3509 that is symmetrical about the centerline 3594 of the rotor 3508. In other cases, one sleeve or more than two sleeves may be used. In some cases, such as that illustrated in FIG. 35, the sleeve 3592 may extend from at or near the end of the rotor 3508 toward the centerline 3594 a distance that is about 60 mm to 140 mm, 70 mm to 130 mm, 80 mm to 120 mm, or 90 mm to 110 mm, or 100 mm or about 100 mm. In some cases, the sleeve 3592 may extend a sufficient distance to cover about 5% to about 25%, e.g., 5% to 25%, 8% to 20%, 10% to 18%, or 15%, or about 5% to about 25%, 8% to about 20%, 10% to about 18%, or about 15% of the total length of the rotor 3508. In some cases, a pair of sleeves 3592, each covering about 20% of the length of the rotor 3508, may together cover 40% of the length of the rotor 3508. In some cases, the sleeve 3592 may be positioned to cover a portion of the rotor 3508 that extends beyond the width of the metal strip being heated. In some cases, the sleeve 3592 may cover anywhere from about 0% to 80% of the total length of the rotor 3508.

[0163] In some cases, the sleeve 3592 may be automatically or manually adjustable to cover more or less of the rotor 3508. In such cases, it may be desirable to adjust the position of the sleeve 3592 based on the width of the metal strip being heated. The sleeve 3592 may, but need not be, coupled to the rotor 3508. To avoid overheating of the sleeve 3592 due to induction heating, particularly if the sleeve 3592 is not fully rotatably coupled to the rotor 3508, the sleeve 3592 may include laminations or other features to reduce the amount of induction heating induced by the changing magnetic field. In some cases, the sleeve 3592 may, but need not be rotatably coupled to the rotor 3508. In some cases, a gap may exist between the sleeve 3592 and the magnetic source within the rotor 3508. This gap may have a distance of 5 mm to 20 mm, 7 mm to 15 mm, or 10 mm, about 5 mm to about 20 mm, about 7 mm to about 15 mm, or about 10 mm.

[0164] The sleeve 3592 can be of any suitable thickness, but in some cases the thickness of the sleeve can be between 1 mm and 50 mm, 10 mm and 50 mm, 1 mm and 30 mm, 15 mm and 40 mm, 20 mm and 30 mm, 10 mm and 20 mm, or about 1 mm and about 50 mm, about 10 mm and about 50 mm, about 1 mm and about 30 mm, about 15 mm and about 40 mm, about 20 mm and about 30 mm, about 10 mm and about 20 mm, or 10 mm or 20 mm, or about 10 mm or about 20 mm.

[0165] The sleeve 3592 may act to reduce the amount of magnetic field extending from the rotor 3508, with the magnetic sources of the rotor 3508 being covered by the sleeve 3592. The sleeve 3592 may short-circuit the magnetic flux. The sleeve 3592 may be positioned to create a desired magnetic flux profile 3509, such as one that provides increased magnetic flux near (e.g., slightly inward from) the edge of the metal strip being heated.

[0166] In some cases, the position and / or % overlap of the rotor sleeve 3592 relative to the rotor 3508 may be controlled to adjust the magnetic flux profile passing through the metal strip. In such cases, the magnetic flux profile 3509 of the rotor 3508 itself may not change dynamically, but the profile of the magnetic flux passing through the metal strip may be dynamically adjusted.

[0167] FIG. 36 is an axonometric, partial schematic view illustrating a magnetic rotor 3608 above a metal strip 3602 with flux guides 3698, according to certain embodiments of the present disclosure. The view in FIG. 36 illustrates the flux guides 3698 and the metal strip 3602 from the surface of the metal strip 3602 upward. In some cases, flux guides 3698 of the same configuration and type may be located symmetrically about the center plane of the metal strip (e.g., a plane that bisects the thickness of the metal strip). For illustrative purposes, the portion of the flux guides 3698 hidden by the rotor 3608 is shown with dotted lines.

[0168] The flux guide 3698 may be positioned adjacent to but spaced from the edge of the metal strip 3602. The flux guide 3698 may be shaped such that its upper surface is contoured to the shape of the magnetic rotor 3608 such that the flux guide 3698 may be positioned in close proximity to the rotor 3608. The rotor 3608 may extend beyond the edge of the metal strip 3602. The flux guide 3698 may act to deflect magnetic flux around the edge of the metal strip 3602 and thus minimize any overheating of the edge of the metal strip 3602.

[0169] The flux guide 3698 can be of any suitable material, such as those described herein for flux guides. The flux guide 3698 can be of any suitable dimensions. In some cases, the flux guide 3698 can be, but need not be, about 100 mm long and about 30 mm wide. The flux guide 3698 can be, but need not be, positioned about 15 mm from the rotor 3608 and about 10 mm from the edge of the metal strip 3602.

[0170] FIG. 37 is an axonometric, partial schematic view illustrating a magnetic rotor 3708 above a metal strip 3702 with bar-shaped flux guides 3798, according to certain embodiments of the present disclosure. The view in FIG. 37 illustrates the bar-shaped flux guides 3798 and the metal strip 3702 from the surface of the metal strip 3702 upward. In some cases, flux guides 3798 of the same configuration and type may be located symmetrically about the center plane of the metal strip (e.g., a plane that bisects the thickness of the metal strip). For illustrative purposes, the portion of the flux guides 3798 hidden by the rotor 3708 is shown with dotted lines.

[0171] The flux guide 3798 may be positioned adjacent to but spaced from the edge of the metal strip 3702. The flux guide 3798 may be rod-shaped and may extend a length greater than the diameter of the rotor 3708. The rotor 3708 may extend beyond the edge of the metal strip 3702. The flux guide 3798 may act to deflect magnetic flux around the edge of the metal strip 3702 as well as to impede and / or absorb secondary magnetic flux generated by the metal strip 3702, thus minimizing any overheating of the edge of the metal strip 3702.

[0172] The flux guide 3798 can be of any suitable material, such as those described herein for flux guides. The flux guide 3798 can be of any suitable dimensions. In some cases, the flux guide 3798 can be, but need not be, about 300 mm long and about 30 mm wide. The flux guide 3798 can be, but need not be, positioned about 25 mm from the rotor 3708 and about 10 mm from the edge of the metal strip 3702.

[0173] In some cases, a desirable flux guide 3798 may have a small width (e.g., about 10 mm), a medium thickness (e.g., about 60 mm), and a relatively large width (e.g., about 400 mm or more). A small width may minimize the magnetic force on the rotor 3808.

[0174] FIG. 38 is an axonometric, partial schematic view illustrating a magnetic rotor 3808 above a metal strip 3802 with edge shielding flux guides 3898, according to certain embodiments of the present disclosure. The view in FIG. 38 illustrates the edge shielding flux guides 3898 and the metal strip 3802 from the surface of the metal strip 3802 upward. In some cases, flux guides 3898 of the same configuration and type may be located symmetrically about the center plane of the metal strip (e.g., a plane that bisects the thickness of the metal strip). For illustrative purposes, the portion of the flux guides 3898 hidden by the rotor 3808 is shown with dotted lines.

[0175] The flux guide 3898 may be positioned adjacent to and spaced apart from the edge of the metal strip 3802. The flux guide 3898 may be positioned between the rotor 3808 and the metal strip 3802. In some cases, the flux guide 3898 may extend beyond the edge of the metal strip 3802. The flux guide 3898 may be positioned at any suitable lateral distance and may extend the entire width of the metal strip 3802 or less. The flux guide 3898 may be generally flat and band-shaped and may, but need not, extend a length (e.g., in the downstream direction) that exceeds the diameter of the rotor 3808. The rotor 3808 may extend beyond the edge of the metal strip 3802. The flux guide 3898 may generate its own secondary magnetic flux and thus act to minimize any overheating of the edge of the metal strip 3802.

[0176] The flux guide 3898 can be any suitable material, such as those described herein with respect to flux guides, such as copper, aluminum, or any electrically conductive material. The flux guide 3898 can be of any suitable dimensions. In some cases, the flux guide 3898 can be about 100 mm long and about 30 mm wide, but this need not be the case. The flux guide 3898 overlaps the metal strip 3802 from the edge of the metal strip 3802 to control the degree to which the flux guide 3898 reduces the amount of heating that occurs at the edge of the metal strip 3802. In some cases, the overlap can be between 10 mm and 70 mm, between 20 mm and 60 mm, between 30 mm and 50 mm, or between 40 mm, or between about 10 mm and about 70 mm, between about 20 mm and about 60 mm, between about 30 mm and about 50 mm, or about 40 mm. In addition, the thickness of the flux guide 3898 can affect the extent to which the flux guide 3898 reduces the amount of heating that occurs at the edges of the metal strip 3802. In some cases, the thickness of the flux guide 3898 can be between 1 mm and 10 mm, between 3 mm and 7 mm, or between 5 mm, or between about 1 mm and about 10 mm, between about 3 mm and about 7 mm, or about 5 mm. In some cases, the thickness of the flux guide 3898 can be dynamically adjusted by sliding individual metal sheets in and out of the flux guide 3898. In addition, the gap between the flux guide 3898 and the rotor 3808 and the gap between the flux guide 3898 and the strip 3802 can affect the extent to which the flux guide 3898 reduces the amount of heating that occurs at the edges of the metal strip 3802. In some cases, the gap between the flux guide 3898 and the strip 3802 can be 5 mm to 50 mm, 10 mm to 40 mm, or 20 mm, or about 5 mm to about 50 mm, about 10 mm to about 40 mm, or about 20 mm. Additionally, the length of the flux guide 3898 (e.g., in a downstream direction perpendicular to the axis of rotation of the rotor 3808) can affect the strength with which the flux guide 3898 reduces the amount of heating that occurs at the edges of the metal strip 3802. In some cases, the length of the flux guide 3898 can be 100 mm to 600 mm, 200 mm to 500 mm, or 300 mm, or about 100 mm to about 600 mm, about 200 mm to about 500 mm, or about 300 mm.Additionally, the width of the flux guides 3898 (e.g., in a direction parallel to the axis of rotation of the rotor 3808) can affect the strength with which the flux guides 3898 reduce the amount of heating that occurs at the edges of the metal strips 3802. In some cases, the width of the flux guides 3898 can be between 40 mm and 160 mm, between 50 mm and 150 mm, or between 100 mm, or between about 40 mm and about 160 mm, between about 50 mm and about 150 mm, or about 100 mm.

[0177] In some cases, the flux guides 3898 may be positioned to overlap only certain portions of the metal strip 3802, without overlapping the edges of the metal strip 3802. For example, the flux guides 3898 may be positioned to overlap only lateral regions where cold spots tend to form.

[0178] FIG. 39 is an axonometric, partially schematic view illustrating a magnetic rotor 3908 above a metal strip 3902 with a magnetic flux conductor 3998, according to certain embodiments of the present disclosure. The view of FIG. 39 illustrates the magnetic flux conductor 3998 and the metal strip 3902 from the surface of the metal strip 3902 upward. In some cases, an identical configuration and type of magnetic flux conductor 3998 may be located symmetrically about the center plane of the metal strip (e.g., a plane that bisects the thickness of the metal strip). An identical magnetic flux conductor 3998 may be located behind the rotor 3908 (e.g., on the opposite side of a plane perpendicular to the surface of the metal strip 3902 and intersecting the axis of rotation of the rotor 3908). The magnetic flux conductor 3998 may be similar to the magnetic flux conductor 766 of FIG. 7.

[0179] In some cases, the magnetic flux conductor 3998 may extend across the entire width of the metal strip 3902, and across less than or more than the entire width of the metal strip 3902. However, in some cases, the magnetic flux conductor 3998 may have a width that is less than the width of the metal strip 3902 and may be positioned to direct magnetic flux into the metal strip 3902 in lateral regions where cold spots may occur. The magnetic flux conductor 3998 may be any suitable material, such as those described herein with respect to magnetic flux conductors and flux guides. The magnetic flux conductor 3998 may be of any suitable dimensions.

[0180] FIG. 40 is a schematic illustration of a cure chamber 4000 according to certain embodiments of the present disclosure. In some cases, the cure chamber 4000 includes a housing 4005, which may be constructed of a non-magnetic material. A coated metal strip 4010 traveling in a rolling direction 4020 may enter the cure chamber through an inlet port 4030. The coated metal strip 4010 may be any suitable metal of any thickness having a coating applied to one or both of its top and bottom surfaces (e.g., coated aluminum sheet, coated steel plate, coated copper foil, coated stainless steel sheet, or coated tin plate, to name a few). In one example, the coated metal strip 4010 is aluminum can end stock or aluminum can body stock, but this need not be the case. In some examples, the coated metal strip 4010 may be substantially horizontal or in any other suitable processing orientation. The coated metal strip 4010 may pass through one or more adjacent upper magnetic rotors 4040 (e.g., disposed above the coated metal strip 4010) and one or more adjacent lower magnetic rotors 4045 (e.g., disposed below the coated metal strip 4010). In some configurations, only an upper magnetic rotor 4040 is present, and in other configurations, only a lower magnetic rotor 4045 is present. The curing chamber 4000 may include any suitable number of upper magnetic rotors 4040 and / or lower magnetic rotors 4045. Each magnetic rotor (e.g., a lower magnetic rotor 4045 or an upper magnetic rotor 4040) may be a magnetic rotor disclosed herein, such as magnetic rotors 108, 110 of FIG. 1 .

[0181] Each upper magnetic rotor 4040 and / or lower magnetic rotor 4045 includes one or more magnets 4050. The one or more magnets 4050 may be arranged on / in each rotor in any suitable manner. FIG. 40 illustrates one non-limiting example in which four magnets 4050 are arranged centered on a surface 4055 of the magnetic rotors 4040, 4045. In some non-limiting examples, the magnets 4050 are at least partially embedded within the magnetic rotors 4040, 4045. In other examples, the magnets 4050 are coupled to or attached to the surface 4055. Each magnetic rotor 4040, 4045 may include any number of magnets 4050 having any suitable cross-sectional shape. For example, the magnets 4050 may be rectangular, triangular, square, any other geometric shape, or any combination thereof. The magnets 4050 may be permanent magnets and / or electromagnets. Although the magnetic rotors 4040, 4045 are illustrated as cylindrical drums, they may have any suitable cross-sectional shape and dimensions.

[0182] In some cases, the curing chamber 4000 is configured so that a majority of the magnetic flux generated from the magnetic rotors 4040, 4045 is directed toward the surface of the metal strip to concentrate heat generation near the metal strip. In some cases, the magnetic flux is directed so that the center of the metal strip is heated less than the outer surface of the metal strip. In some cases, any of the magnetic flux concentrators or diverters described above may be used. By concentrating heat generation near the surface of the metal strip, heat may be used to cure the coating with minimal impact on the metallurgical properties of the metal strip.

[0183] If the curing chamber 4000 includes both an upper magnetic rotor 4040 and a lower magnetic rotor 4045, the upper magnetic rotor 4040 may be vertically aligned with or vertically offset from the lower magnetic rotor 4045, as shown in FIG. 40 , to form a curing stack 4070. In some examples, at least some of the upper magnetic rotors 4040 are configured to rotate in a first direction 4060, while at least some of the lower magnetic rotors 4045 are configured to rotate in a second direction 4065 that is opposite the first direction 4060. As shown in FIG. 40 , an exemplary curing chamber 4000 may include multiple curing stacks 4070. In some cases, each curing stack 4070, or a subset of the curing stacks 4070, may be individually controlled to provide separate heating zones within the curing chamber 4000. In configurations where only the upper magnetic rotor 4040 or only the lower magnetic rotor 4045 is used, each upper magnetic rotor (or lower magnetic rotor) or subset of the upper magnetic rotors (or lower magnetic rotors) can be operated individually to provide separate heating zones within the curing chamber 4000.

[0184] In some non-limiting examples, controlling the rotors 4040, 4045 or the cure stack 4070 to provide separate heating zones can be performed by adjusting one or more of the following parameters: (i) A distance 4075 between each magnetic rotor 4040, 4045 and the coated metal strip 4010 (if both an upper and lower magnetic rotor 4040, 4045 are used, the distances 4075 add up to the thickness of the metal strip 4010 to form a gap 4076 between each magnetic rotor 4040, 4045). Positioning the magnetic rotors 4040, 4045 closer to the coated metal strip 4010 may increase the temperature transferred to the coated metal strip 4010 and any coating applied to the coated metal strip 4010. Positioning the magnetic rotors 4040, 4045 farther from the coated metal strip 4010 may decrease the temperature transferred to the coated metal strip 4010 and any coating applied to the coated metal strip 4010. In some examples, positioning the magnetic rotors 4040, 4045 closer to the coated metal strip 4010 may increase the temperature transferred to the coated metal strip 4010 and the coating applied to the coated metal strip 4010. In some further examples, positioning the magnetic rotors 4040, 4045 farther from the coated metal strip 4010 may decrease the temperature transferred to the coated metal strip 4010 and the coating applied to the coated metal strip 4010. (ii) Rotational speed of the magnetic rotors 4040, 4045. Increasing the rotational speed of the magnetic rotors 4040, 4045 may increase the temperature transferred to the coated metal strip 4010 and the coating applied to the metal strip 4010. Decreasing the rotational speed of the magnetic rotors 4040, 4045 may decrease the temperature transferred to the coated metal strip 4010 and the coating applied to the metal strip 4010. (iii) The strength and / or direction of the magnetic flux emanating from the magnetic rotors 4040, 4045. Increasing the strength of the magnetic flux emanating from the magnetic rotors 4040, 4045 may increase the temperature transferred to the coated metal strip 4010 and the coating applied to the metal strip 4010. Similarly, directing the magnetic flux emanating from the magnetic rotors 4040, 4045 toward the outer surface of the metal strip may increase the temperature transferred to the coating applied to the metal strip 4010. (iv) the distance 4077 between the first magnetic rotor 4040, 4045 and any additional magnetic rotors 4040, 4045 disposed adjacent the first magnetic rotor 4040, 4045 on the same side of the coated metal strip 4010, or the distance 4077 between the first hardening stack 4070 and any second hardening stack 4070. In some examples, positioning the first magnetic rotor 4040, 4045 closer to any second magnetic rotor 4040, 4045 may increase the temperature transferred to the coated metal strip 4010 and the coating applied to the coated metal strip 4010. In some further examples, positioning the first magnetic rotor 4040, 4045 farther from any second magnetic rotor 4040, 4045 may decrease the temperature transferred to the coated metal strip 4010 and the coating applied to the coated metal strip 4010. In some cases, positioning the first hardening stack 4070 closer to any second hardening stack 4070 may increase the temperature transferred to the coated metal strip 4010 and the coating applied to the coated metal strip 4010. In some further examples, positioning the first hardening stack 4070 farther from any second hardening stack 4070 may decrease the temperature transferred to the coated metal strip 4010 and the coating applied to the coated metal strip 4010.

[0185] In some non-limiting examples, controlling the speed at which the coated metal strip passes through each heating zone (e.g., strip speed through the curing chamber), in conjunction with the parameters for providing the separate heating zones described above, can be used to control the heating of the coated metal strip and any applied coatings. More specifically, in some embodiments, the strip speed can be adjusted to control the temperature transferred from the magnetic rotors 4040, 4045 to the metal strip and any coatings applied to the metal strip. Increasing the strip speed can decrease the temperature transferred to the coated metal strip 4010 and any coatings applied to the metal strip 4010, while decreasing the strip speed can increase the temperature transferred to the coated metal strip 4010 and any coatings applied to the metal strip 4010 (i.e., a slower strip speed increases the residence time of the metal strip and any coatings applied to the metal strip in the curing chamber). Additionally, in some examples, controlling the strip speed of the metal strip and the coating applied thereto can control the residence time of the metal strip and the coating applied thereto as it passes adjacent to the magnetic rotor 4040, 4045 or the cure stack 4070. In some non-limiting examples, the metal strip can be heated to a target temperature of at least 250° C. in less than about 5 seconds at a rate greater than about 50° C. / sec when the speed of the magnetic rotor is at least 1,300 RPM.

[0186] The coated metal strip 4010 may pass through the curing chamber 4000 at any suitable strip speed. By way of non-limiting example, the strip speed may range from about 20 meters per minute (m / min) to about 400 m / min (e.g., about 20 m / min, about 30 m / min, about 40 m / min, about 50 m / min, about 60 m / min, about 70 m / min, about 80 m / min, about 90 m / min, about 100 m / min, about 110 m / min, about 120 m / min, about 130 m / min, about 140 m / min, about 150 m / min, about 160 m / min, about 170 m / min, about 180 m / min, about 190 m / min, about 200 m / min, about 210 m / min, about 220 m / min, and the like). / min, about 230 m / min, about 240 m / min, about 250 m / min, about 260 m / min, about 270 m / min, about 280 m / min, about 290 m / min, about 300 m / min, about 310 m / min, about 320 m / min, about 330 m / min, about 340 m / min, about 350 m / min, about 360 m / min, about 370 m / min, about 380 m / min, about 390 m / min, about 400 m / min, or any speed therebetween) or other suitable speed for curing the coating present on the metal strip.

[0187] One or more of the above parameters can be adjusted to heat at least the surface of the metal strip 4010 to a temperature sufficient to cure the coating on the metal strip 4010. In some cases, the above parameters are predetermined to heat the surface of the metal strip 4010 to a temperature sufficient to cure the coating on the metal strip 4010 within a desired distance (such as the length of the curing chamber 4000) and / or within a desired time period.

[0188] The upper magnetic rotor 4040 and / or the lower magnetic rotor 4045 may be vertically adjustable to control the distance 4075 between each magnetic rotor (or subset of magnetic rotors) 4040, 4045 and the coated metal strip 4010. As described above, positioning the magnetic rotors 4040, 4045 closer to the coated metal strip 4010 may increase the strength of the magnetic field within the coated metal strip 4010, which in turn may increase the magnitude of eddy currents within the coated metal strip, and therefore may generate more heat in the coated metal strip. Similarly, in some cases, positioning the magnetic rotors 4040, 4045 farther from the coated metal strip 4010 may decrease the strength of the magnetic field within the coated metal strip 4010, which in turn may decrease the magnitude of eddy currents within the coated metal strip, and therefore may generate less heat in the coated metal strip. In some cases, the distance 4075 from the magnetic rotor 4040, 4045 to the coated metal strip 4010 is between about 15 mm and about 300 mm (e.g., about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 25 mm, about 30 mm, about 35 mm, about 40 mm, about 45 mm, about 50 mm, about 55 mm, about 60 mm, about 65 mm, about 70 mm, about 75 mm, about 80 mm, about 85 mm, about 90 mm, about 95 mm, about 100 mm, about 105 mm, about 110 mm, about 115 mm, about 120 mm, about 125 mm, about 130 mm, about 135 mm, 140 mm, about 145 mm, about 150 mm, about 155 mm, about 160 mm, about 165 mm, about 170 mm, about 175 mm, about 180 mm, about 185 mm, about 190 mm, about 195 mm, about 200 mm, about 205 mm, about 210 mm, about 215 mm, about 220 mm, about 225 mm, about 230 mm, about 235 mm, about 240 mm, about 245 mm, about 250 mm, about 255 mm, about 260 mm, 265 mm, about 270 mm, about 275 mm, about 280 mm, about 285 mm, about 290 mm, about 295 mm, about 300 mm, or any value therebetween.In some cases, the distance 4075 is less than 15 mm, and in other cases, more than 300 mm. In this manner, the curing chamber 4000 may be constructed as a levitation chamber, where the coated metal strip 4010 passes through the curing chamber 4000 without contacting the magnetic rotors 4040, 4045. After curing, the coated metal strip 4010 exits the exemplary curing chamber 4000 through the exit port 4080.

[0189] In some cases, using a rotating magnet to heat a metal strip (e.g., aluminum sheet, aluminum can body stock, or aluminum can end stock (CES)) and a coating applied to the surface of the metal strip can provide simple and fast temperature control of the metal strip, the coating applied to the metal strip, and the environment within the curing chamber.

[0190] For example, at least one or more surfaces of the metal strip and the coating applied to one or more surfaces of the metal strip can be heated to any suitable temperature. In a non-limiting example, at least one or more surfaces of the metal strip and the coating applied to one or more surfaces of the metal strip can be heated to about 100°C to about 600°C (e.g., about 100°C, about 125°C, about 150°C, about 175°C, about 200°C, about 225°C, about 250°C, about 275°C, about 300°C, about 325°C, about 350°C, about 355°C, about 375°C, about 400°C, about 425°C, about 450°C, about 475°C, about 500°C, about 525°C, about 550°C, about 575°C, about 600°C, or any temperature therebetween), or other temperature sufficient to cure the coating of the metal strip 4010 (e.g., less than 100°C or greater than 600°C). The curing chamber 4000 can be configured so that the metal strip and the coating applied to the metal strip can be heated to the target temperature within about 1 second to about 10 seconds (e.g., about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, about 9 seconds, about 10 seconds, or any time in between), or any other desired time. In some cases, the metal strip and the coating applied to the metal strip are heated at a rate of about 1° C. / second to about 150° C. / second or greater (e.g., about 1° C. / second or greater, about 2° C. / second or greater, about 3° C. / second or greater, about 4° C. / second or greater, about 5° C. / second or greater, about 10° C. / second or greater, about 15° C. / second or greater, about 20° C. / second or greater, about 25° C. / second or greater, about 30° C. / second or greater, about 35° C. / second or greater, about 40° C. / second or greater, about 45° C. / second or greater, about 50° C. / second or greater, about 55° C. / second or greater, about 60° C. / second or greater). The metal strip may be heated to the target temperature at a rate of about 65° C. / sec or greater, about 70° C. / sec or greater, about 75° C. / sec or greater, about 80° C. / sec or greater, about 85° C. / sec or greater, about 90° C. / sec or greater, about 95° C. / sec or greater, about 100° C. / sec or greater, about 105° C. / sec or greater, about 110° C. / sec or greater, about 115° C. / sec or greater, about 120° C. / sec or greater, about 125° C. / sec or greater, about 130° C. / sec or greater, about 135° C. / sec or greater, about 140° C. / sec or greater, about 145° C. / sec, about 150° C. / sec or greater, or any rate therebetween. In some cases, the metal strip and the coating applied to the metal strip may be heated to the target temperature at a rate greater than 150° C. / sec.

[0191] In some embodiments, the above temperatures, times, and speeds can be controlled by controlling the rotational speed of the magnetic rotors 4040, 4045. For example, increasing the rotational speed of the magnetic rotors 4040, 4045 can increase the oscillation of the magnetic field within the metal strip and the coating applied thereto, thereby increasing the magnitude of eddy currents within the metal strip and the coating applied thereto, thereby generating more heat within the metal strip and the coating applied thereto. Similarly, decreasing the rotational speed of the magnetic rotors 4040, 4045 can decrease the oscillation of the magnetic field within the metal strip and the coating applied thereto, thereby decreasing the magnitude of eddy currents within the metal strip and the coating applied thereto, thereby generating less heat within the metal strip and the coating applied thereto. The magnetic rotors can rotate at any suitable speed. In some cases, each magnetic rotor has a rotational speed of about 200 RPM to about 3,500 RPM (e.g., about 200 RPM, about 250 RPM, about 300 RPM, about 350 RPM, about 400 RPM, about 450 RPM, about 500 RPM, about 550 RPM, about 600 RPM, about 650 RPM, about 700 RPM, about 750 RPM, about 800 RPM, about 850 RPM, about 900 RPM, about 950 RPM, about 1,000 RPM, about 1,100 RPM, about 1,200 RPM, about 1,300 RPM, about 1,400 RPM, about 1,500 RPM). The magnetic rotor may rotate at a speed of about 1,600 RPM, about 1,700 RPM, about 1,800 RPM, about 1,900 RPM, about 2,000 RPM, about 2,100 RPM, about 2,200 RPM, about 2,300 RPM, about 2,400 RPM, about 2,500 RPM, about 2,600 RPM, about 2,700 RPM, about 2,800 RPM, about 2,900 RPM, about 3,000 RPM, about 3,100 RPM, about 3,200 RPM, about 3,300 RPM, about 3,400 RPM, about 3,500 RPM, or any speed therebetween. In some cases, the magnetic rotor rotates at a speed less than 200 RPM or greater than 3,500 RPM.

[0192] Each of the upper magnetic rotors 4040 and / or each of the lower magnetic rotors 4045 may rotate at the same speed or at a different speed relative to the other magnetic rotors in the system.

[0193] 41 is a perspective view illustrating an example of a magnetic rotor 4040, 4045, according to certain embodiments of the present disclosure. In some configurations, one or more magnets 4050 are at least partially embedded within the magnetic rotor 4040, 4045.

[0194] 42 is a cross-sectional view illustrating an example of a magnetic rotor 4040, 4045, according to certain embodiments of the present disclosure. The magnetic rotor 4040, 4045 may include one or more magnets 4050 at least partially embedded within the magnetic rotor 4040, 4045.

[0195] 43 is a cross-sectional view illustrating one example of a magnetic rotor 4040, 4045, according to certain embodiments of the present disclosure. In some cases, one or more magnets 4050 may be attached to or otherwise coupled with the magnetic rotor 4040, 4045 such that they protrude from a surface 4055 of the magnetic rotor 4040, 4045.

[0196] 44 is a cross-sectional view illustrating one example of a magnetic rotor 4040, 4045, according to certain embodiments of the present disclosure. In some cases, a subset 4050 of the magnets may be embedded within the magnetic rotor 4040, 4045, while another subset of the magnets may protrude from a surface 4055 of the magnetic rotor 4040, 4045. Any other suitable arrangement or configuration of magnets relative to the rotor may be used other than those illustrated in FIGS. 42-44.

[0197] FIG. 45 is a graph of an example of a cure chamber temperature profile for a comparative gas-fired cure chamber. The y-axis shows temperature (°C), and the x-axis shows residence time (seconds) in the comparative cure chamber. The temperature of the metal strip and its coating may increase with time spent in the comparative cure chamber. In some cases, the exemplary system for curing coatings described herein may be comparable to the comparative gas-fired cure chamber temperature profile. The dashed line shows how positioning the magnetic rotor / cure stack 4070 within the exemplary cure chamber 4000 may provide a temperature profile similar to the comparative gas-fired cure chamber. The coated metal strip 4010 may enter the exemplary cure chamber 4000, be exposed to a first temperature 4500, and begin to heat up. The coated metal strip 4010 may subsequently be heated to a second temperature 4510 after passing through the first magnetic rotor / cure stack. The coated metal strip 4010 may further be heated to a third temperature 4520 after passing through the second magnetic rotor / cure stack. The coated metal strip 4010 may also be further heated to a fourth temperature 4530 after passing through a third magnetic rotor / curing stack.

[0198] FIG. 46 is a graph of the rate of temperature rise compared to magnetic rotor speed, according to certain embodiments of the present disclosure. The graph shows the rate of temperature change (e.g., temperature rise) of the surface of a coated metal strip (e.g., coated metal strip 4010 of FIG. 40 ) as a function of the speed of the magnetic rotors (e.g., rotors 4040, 4045) and the gap between the first magnetic rotor (e.g., magnetic rotor 4040) and the second magnetic rotor (e.g., magnetic rotor 4045) and the gap (e.g., gap 4076). The coated metal strip 4010 was centered within gap 4076. The temperature of the coated metal strip 4010 was recorded. As is evident from the graph of FIG. 46 , the rate of temperature rise increases as the speed of the magnetic rotors 4040, 4045 increases, as described above. In some non-limiting examples, maintaining gap 4076 at 30 mm (solid line) provided the greatest rate of temperature rise. In some non-limiting examples, maintaining the gap 4076 at 60 mm (dashed line) provided a lower temperature rise rate than maintaining the gap 4076 at 30 mm. In some non-limiting examples, maintaining the gap 4076 at 90 mm (dotted line) resulted in a lower temperature rise rate than maintaining the gap 4076 at 60 mm. In some non-limiting examples, maintaining the gap 4076 at 120 mm (dashed line) resulted in a lower temperature rise rate than maintaining the gap 4076 at 90 mm. As is further apparent from the graphs, decreasing the gap 4076 between the magnetic rotors 4040 and 4045 (and thus the distance 4075 between the magnetic rotors 4040, 4045 and the coated metal strip 4010) also increases the temperature rise rate of the coated metal strip 4010 and the coating applied to the coated metal strip. In some non-limiting examples, maintaining a gap 4076 between the magnetic rotors 4040 and 4045 of approximately 30 mm and rotating each magnetic rotor 4040, 4045 at a speed of approximately 1,300 RPM can provide a heating rate of approximately 55°C / sec.

[0199] FIG. 47 is a graph of the rate of temperature rise compared to the gap between magnetic rotors, according to certain embodiments of the present disclosure. The graph shows the rate of temperature change (e.g., temperature rise) of the surface of a coated metal strip (e.g., coated metal strip 4010 of FIG. 40) as a function of the gap (e.g., gap 4076) between the magnetic rotors (e.g., rotors 4040 and 4045). The rotor speed was maintained at approximately 1,500 RPM. As is apparent from the graph in FIG. 47, increasing the gap 4076 between the magnetic rotors 4040 and 4045 (and thus the distance 4075 between the magnetic rotors 4040, 4045 and the coated metal strip 4010) decreases the rate of temperature rise of the coated metal strip 4010 and the coating applied to the coated metal strip. In some non-limiting examples, maintaining a gap 4076 between the magnetic rotors 4040 and 4045 of about 30 mm and rotating each magnetic rotor 4040, 4045 at a speed of about 1,500 RPM can provide a heating rate of about 65°C / sec. In another example, maintaining a gap 4076 of about 100 mm and a speed of the magnetic rotors 4040, 4045 of 1,500 RPM can provide a heating rate of about 15°C / sec.

[0200] In some non-limiting examples, the temperature profile of a curing chamber as described herein can be precisely tailored to the coated metal or other material strip and its coating characteristics by adjusting parameters including the strip speed of the coated metal strip, the rotational speed of the magnetic rotor, the strength and / or direction of the magnetic flux generated from the magnetic rotor, the distance between the magnetic rotor and the coated metal or other material strip, and / or the distance between adjacent magnetic rotors. In some cases, the systems described herein can provide reduced start-up and shutdown times for the curing system, provide a curing chamber with a smaller footprint than a comparable gas-fired curing chamber, provide reduced curing times for coatings applied to metal and other material strips, and provide reduced fossil fuel emissions. For example, a coated metal strip having a strip speed of about 200 m / min requires a typical curing chamber having a length of about 15 m, while a comparable gas-fired curing chamber requires a length of 50 m for equivalent curing. The curing chambers described herein can, in some cases, be about 70% shorter than a comparable gas-fired curing chamber.

[0201] FIG. 48 is a schematic illustration of a curing chamber and heat transfer medium heating oven according to certain embodiments of the present disclosure. In some non-limiting examples, the systems described herein can be used to provide heat outside the curing chamber 4000 or otherwise away from the magnetic rotor (e.g., rotors 108, 110 of FIG. 1 ). For example, a blower can be used to transport any heated gas (e.g., air, nitrogen, argon, or any suitable process gas) or liquid contained within the curing chamber 4000 to an adjacent process or process chamber. In some cases, volatile organic compounds (VOCs) extracted from the coating during curing can be sent to an optional regenerative thermal oxidizer (RTO) to capture heat energy from the VOCs. In some examples, gases extracted from the coating during curing can be sent to an optional scrubber to provide environmentally safe emissions from the curing chamber 4000.

[0202] 48 , one example of the system described herein may be used to heat water or any other suitable heat exchange material (e.g., air, gas, liquid) for use in systems and processes outside the curing chamber 4000. A conduit 4810 disposed adjacent to one or more of the individual rotors 4040, 4045, or curing stack 4070 may carry a heat exchange fluid 4820 for efficient heat transfer within the conduit 4810. In some examples, the conduit 4810 is a closed system and / or is connected to a vessel for storing and filtering the heat exchange fluid 4820. One or more tubes 4830 may transport the heat exchange fluid 4820 through the curing chamber 4000 to heat the heat exchange fluid 4820 using the magnets of the individual rotors 4040, 4045, or curing stack 4070, and then transport the heated heat exchange fluid 4820 to a system or process adjacent to the curing chamber 4000. In some cases, one or more tubes 4830 may contact or be positioned in close proximity to conduit 4810 to improve heat transfer rate and efficiency. For example, multiple tubes 4830 may transport water to an adjacent rinse station that requires high temperature and / or warm water, for example, to remove cleaning fluid from the metal strip (e.g., rinse) after the cleaning process.

[0203] The foregoing description of embodiments, including the illustrated embodiment, has been presented only for purposes of illustration and description and is not intended to be exhaustive or limited to the precise form disclosed. Numerous modifications, adaptations and uses thereof will be apparent to those skilled in the art.

[0204] As used hereinafter, any reference to a series of examples should be understood disjunctively as a reference to each of those examples (e.g., "Examples 1-4" should be understood as "Examples 1, 2, 3, or 4").

[0205] Example 1 is a rotary magnet heating system comprising: a magnetic rotor including at least one magnetic source, rotatable about a rotation axis to generate a changing magnetic field adjacent to the magnetic rotor, the magnetic rotor positionable adjacent a metal article moving in a downstream direction so that the changing magnetic field passes through the metal article, the rotation axis being perpendicular to the downstream direction and parallel to within 10° of a lateral width of the metal article; and at least one motor coupled to the magnetic rotor to rotate the magnetic rotor. In some cases, the rotation axis is parallel to the lateral width of the metal article.

[0206] Example 2 is the rotary magnet heating system of example 1, wherein the at least one magnetic source is at least one permanent magnet.

[0207] Example 3 is the rotary magnet heating system of Examples 1 or 2, further including a second magnetic rotor spaced apart from the magnetic rotor to form a gap for receiving the metal article, the second magnetic rotor containing at least one magnetic source and rotatable about a second axis of rotation parallel to the axis of rotation.

[0208] Example 4 is the rotary magnet heating system of Examples 1 to 3, further comprising a support arm coupled to the magnetic rotor for adjusting the distance between the magnetic rotor and the metal article.

[0209] Example 5 is the rotary magnet heating system of Examples 1-4, further comprising a supplemental heating element positioned adjacent to the metal article and between the edge of the metal article and the lateral centerline of the metal article.

[0210] Example 6 is the rotary magnet heating system of example 5, wherein the auxiliary heating element includes an auxiliary magnetic rotor having a length that is shorter than the length of the magnetic rotor.

[0211] Example 7 is the rotary magnet heating system of examples 1-6, further comprising one or more magnetic flux guides positioned adjacent to the magnetic rotor to redirect at least a portion of the magnetic flux from the magnetic rotor.

[0212] Example 8 is the rotary magnet heating system of example 7, wherein one or more flux guides are coupled to the magnetic rotor.

[0213] Example 9 is the rotary magnet heating system of examples 1-8, further comprising one or more deflectors positioned to move the metal article to adjust the distance between the metal article and the magnetic rotor.

[0214] Example 10 is the rotary magnet heating system of Examples 1-9, further including a sensor positioned to measure a temperature or tension of the metal article and a controller coupled to the sensor to receive the sensor signal, the controller coupled to an actuator associated with the magnetic rotor to provide feedback control in response to the sensor signal, and the actuator configured to control the amount of magnetic flux passing through the metal article.

[0215] Example 11 is a method of magnetically heating a metal article, comprising: rotating a magnetic rotor about an axis of rotation to induce a changing magnetic field adjacent to the magnetic rotor; and passing the metal article adjacent to the magnetic rotor and through the changing magnetic field to induce eddy currents in the metal article, wherein passing the metal article comprises moving the metal article in a downstream direction perpendicular to the axis of rotation of the magnetic rotor, and the metal article is oriented such that a lateral width of the metal article is parallel to the axis of rotation of the magnetic rotor within 10°. In some cases, the metal article is parallel to the axis of rotation of the magnetic rotor.

[0216] Example 12 is the method of example 11, wherein rotating the magnetic rotor about the axis of rotation includes moving at least one permanent magnet around the axis of rotation.

[0217] Example 13 is the method of example 11 or 12, further including rotating a second magnetic rotor about a second axis of rotation that is parallel to the axis of rotation of the magnetic rotor, wherein the second magnetic rotor is spaced from the magnetic rotor to form a gap, and wherein passing the metal article adjacent to the metal rotor includes passing the metal article through the gap.

[0218] Example 14 is the method of examples 11-13, further comprising dynamically varying the distance between the magnetic rotor and the metal article.

[0219] Example 15 is the method of examples 11-14, further including passing the metal article adjacent to the auxiliary heating element and heating a region of the metal strip using the auxiliary heating element, the region being located between an edge of the metal article and a lateral centerline of the metal article.

[0220] Example 16 is the method of example 15, wherein heating the region of the metal strip using the auxiliary heating element includes rotating an auxiliary magnetic rotor, and the auxiliary magnetic rotor has a length that is shorter than the length of the magnetic rotor.

[0221] Example 17 is the method of examples 11-16, further including providing one or more magnetic flux guides adjacent to the magnetic rotor, wherein providing the one or more magnetic flux guides includes redirecting at least a portion of the magnetic field.

[0222] Example 18 is the method of example 17, in which providing the one or more flux guides includes providing a metal rotor, the metal rotor having the one or more flux guides coupled thereto.

[0223] Example 19 is the method of examples 11-18, further comprising deflecting the metallic article to adjust the distance between the metallic article and the magnetic rotor.

[0224] Example 20 is the method of examples 11-19, further including measuring a temperature or tension of the metal article and dynamically providing feedback control based on the measured temperature or the measured tension, wherein dynamically providing feedback control results in manipulation of the changing magnetic field or the position of the metal article relative to the changing magnetic field.

[0225] Example 21 is a rotary magnetic heater comprising: an upper magnetic rotor vertically offset from a lower magnetic rotor defining a gap therebetween for receiving a moving metal strip; at least one motor coupled to at least one of the upper magnetic rotor and the lower magnetic rotor for rotating at least one of the upper magnetic rotor and the lower magnetic rotor to induce a changing magnetic field through the gap for heating the moving metal strip; and a pair of support arms each coupled to one of the upper magnetic rotor and the lower magnetic rotor for adjusting the gap.

[0226] Example 22 is the rotary magnet heater of Example 21, further comprising an additional upper magnetic rotor vertically offset from the additional lower magnetic rotor, defining a gap therebetween for receiving a moving metal strip, and an additional pair of support arms each connected to one of the additional upper magnetic rotor and the additional lower magnetic rotor to adjust the additional gap.

[0227] Example 23 is the rotary magnet heater of Example 22, further comprising at least one actuator coupled to at least one of the pair of support arms and the additional pair of support arms to adjust the gap in response to a signal, and a controller coupled to the at least one actuator to provide the signal.

[0228] Example 24 is the rotary magnet heater of example 23, further comprising a sensor coupled to the controller to provide a measurement to the controller, the controller configured to provide a signal based on the measurement.

[0229] Example 25 is the rotary magnet heater of Examples 22-24, wherein the additional upper magnetic rotor is laterally offset from the additional lower magnetic rotor such that the overlap between the upper magnetic rotor and the lower magnetic rotor is less than the width of the moving metal strip.

[0230] Example 26 is the rotary magnet heater of Examples 21 to 25, further comprising an idler roller coupled to an extendable support arm movable between an extended position and a retracted position, wherein at least one of the upper magnetic rotor and the lower magnetic rotor is coupled to the extendable support arm, and the moving metal strip passes adjacent to the upper magnetic rotor and the lower magnetic rotor when the extendable support arm is in the extended position, and the moving metal strip passes away from the upper magnetic rotor and the lower magnetic rotor when the extendable support arm is in the retracted position.

[0231] Example 27 is a metal processing system comprising: a metal piece processing facility for processing a moving metal strip; a rotary magnetic heater including a first magnetic rotor set, the first magnetic rotor set being an upper magnetic rotor vertically offset from a lower magnetic rotor to define a gap therebetween for receiving the moving metal strip; at least one motor coupled to at least one of the upper magnetic rotor and the lower magnetic rotor for rotating at least one of the upper magnetic rotor and the lower magnetic rotor to induce a changing magnetic field through the gap for heating the moving metal strip; and a pair of support arms each coupled to one of the upper magnetic rotor and the lower magnetic rotor for adjusting the gap.

[0232] Example 28 is the system of Example 27, wherein the metal strip processing equipment is a continuous caster for casting moving metal strip.

[0233] Example 29 is the system of Examples 27 or 28, wherein a rotary magnetic heater is positioned upstream of the metal strip processing equipment to elevate the temperature of the metal strip.

[0234] Example 30 is the system of Example 29, wherein the rotary magnetic heater further includes a second magnetic rotor set, the second magnetic rotor set comprising an additional upper magnetic rotor vertically offset from the additional lower magnetic rotor, defining a gap therebetween for receiving a moving metal strip, and an additional pair of support arms each coupled to one of the additional upper magnetic rotor and the additional lower magnetic rotor to adjust the additional gap.

[0235] Example 31 is the system of Examples 27-30, wherein the rotary magnetic heater further comprises at least one actuator coupled to at least one of the pair of support arms and the additional pair of support arms to adjust the gap in response to a signal, and a controller coupled to the at least one actuator to provide the signal.

[0236] Example 32 is the system of example 31, further comprising a sensor coupled to the controller to provide a measurement value to the controller, the controller configured to provide a signal based on the measurement value.

[0237] Example 33 is the system of examples 27-32, wherein the additional upper magnetic rotor is laterally offset from the additional lower magnetic rotor such that the overlap between the upper magnetic rotor and the lower magnetic rotor is less than the width of the moving metal strip.

[0238] Example 34 is the system of Examples 27-33, further comprising an idler roller coupled to an extendable support arm movable between an extended position and a retracted position, wherein at least one of the upper magnetic rotor and the lower magnetic rotor is coupled to the extendable support arm, and the moving metal strip passes adjacent to the upper magnetic rotor and the lower magnetic rotor when the extendable support arm is in the extended position, and the moving metal strip passes away from the upper magnetic rotor and the lower magnetic rotor when the extendable support arm is in the retracted position.

[0239] Example 35 is a method including: passing a metal strip through a first gap defined between an upper magnetic rotor and a lower magnetic rotor of a first magnetic rotor set; passing the metal strip through a second gap defined between an additional upper magnetic rotor and an additional lower magnetic rotor of a second magnetic rotor set; rotating the first magnetic rotor set at a first speed to induce a first changing magnetic field in the first gap to heat the metal strip; rotating the second magnetic rotor set at a second speed to induce a second changing magnetic field in the second gap to heat the metal strip; and controlling a tension in the metal strip, wherein controlling the tension includes adjusting at least one of the first gap, the second gap, the first speed, and the second speed.

[0240] Example 36 is the method of example 35, further comprising measuring the metal strip, and controlling the tension comprises adjusting based on the measurement.

[0241] Example 37 is the method of example 35 or 36, further comprising adjusting a longitudinal position of at least one of the first magnetic rotor set and the second magnetic rotor set.

[0242] Example 38 is the method of examples 35-37, further comprising adjusting a lateral position of at least one magnetic rotor of at least one of the first magnetic rotor set and the second magnetic rotor set.

[0243] Example 39 is the method of examples 35-38, wherein controlling the tension in the metal strip includes offsetting tension changes induced by the first magnetic rotor set using a second magnetic rotor set.

[0244] Example 40 is the method of examples 35-39, wherein controlling the tension in the metal strip includes adjusting at least one of the first gap and the second gap.

[0245] Example 41 is a magnetic rotor having an adjusted magnetic flux, comprising a central axis of rotation, one or more magnetic sources rotatable about the axis of rotation, and a magnetic flux profile based on the one or more magnetic sources, wherein the magnetic flux profile is non-uniform along the length of the rotor.

[0246] Example 42 is the magnetic rotor of example 41, further comprising one or more magnetic flux guides, wherein the one or more magnetic sources exhibit an initial magnetic flux profile, and the one or more magnetic flux guides are positioned to deflect at least a portion of the initial magnetic flux profile to exhibit a non-uniform magnetic flux profile.

[0247] Example 43 is the magnetic rotor of example 41, wherein the one or more magnetic sources vary over a length of the rotor to exhibit a non-uniform magnetic flux profile. In some cases, example 43 can also include one or more flux guides positioned to deflect at least a portion of the non-uniform magnetic flux profile.

[0248] Example 44 is the magnetic rotor of example 41 or 42, further comprising one or more sleeves positioned around at least a portion of the one or more magnetic sources, the one or more magnetic sources exhibiting an initial magnetic flux profile, and the one or more sleeves positioned to deflect at least a portion of the initial magnetic flux profile to exhibit a non-uniform magnetic flux profile.

[0249] Example 45 is the magnetic rotor of Examples 41-44, wherein the non-uniform magnetic flux profile reaches a maximum amount of magnetic flux between the center of the rotor length and one end of the rotor.

[0250] Example 46 is the magnetic rotor of Examples 41-44, wherein the non-uniform magnetic flux profile reaches a maximum amount of magnetic flux at locations between the center of the rotor length and each end of the rotor.

[0251] Example 47 is a system for curing a coating, comprising: a curing chamber having an inlet and an outlet for passing a coated metal strip through the curing chamber; and at least one rotor having at least one magnet.

[0252] Example 48 is the system of example 47, wherein the at least one magnet includes a plurality of magnets.

[0253] Example 49 is the system of example 47 or 48, wherein the at least one rotor includes a plurality of rotors.

[0254] Example 50 is the system of example 49, wherein a first subset of the plurality of rotors is positioned adjacent to a first side of the coated metal strip, and a second subset of the plurality of rotors is positioned adjacent to a second side of the coated metal strip.

[0255] Example 51 is the system of example 50, wherein at least one rotor of the first subset of the plurality of rotors is vertically aligned with at least one rotor of the second subset of the plurality of rotors.

[0256] Example 52 is the system of example 50 or 51, wherein at least one rotor of the first subset of the plurality of rotors is vertically offset from a rotor of the second subset of rotors.

[0257] Example 53 is the system of Examples 50-52, wherein at least one rotor of the first subset of the plurality of rotors and at least one rotor of the second subset of the plurality of rotors form a hardened stack.

[0258] Example 54 is the system of Example 53, wherein the system includes multiple curing stacks, each curing stack having a heating zone.

[0259] Example 55 is the system of example 54, wherein at least some of the heating zones are individually controllable.

[0260] Example 56 is the system of Examples 54 or 55, wherein at least some of the heating zones are precisely controllable.

[0261] Example 57 is the system of Examples 54-56, wherein at least some of the heating zones are instantly adjustable.

[0262] Example 58 is the system of Examples 54-57, wherein the curing stack includes counter-rotating rotors.

[0263] Example 59 is the system of examples 50-58, wherein at least some of the rotors of a first subset of the plurality of rotors rotate in a first direction and at least some of the rotors of a second subset of the plurality of rotors rotate in a second direction opposite the first direction.

[0264] Example 60 is the system of examples 47-59, wherein the at least one magnet comprises a permanent magnet.

[0265] Example 61 is the system of examples 47-60, wherein the at least one magnet is at least partially embedded within a surface of the at least one rotor.

[0266] Example 62 is the system of Examples 47-61, wherein at least one magnet protrudes from a surface of the at least one rotor.

[0267] Example 63 is the system of Examples 47-62, wherein at least one rotor is positioned within the curing chamber such that the at least one rotor is adjacent to the coated metal strip passing through the curing chamber.

[0268] Example 64 is the system of examples 47-63, wherein at least one rotor is configured to heat the coated metal strip by induction heating.

[0269] Example 65 is the system of examples 47-64, wherein the at least one magnet includes a first magnet at least partially embedded within the at least one rotor and a second magnet protruding from a surface of the at least one rotor.

[0270] Example 66 is a method including: rotating at least one rotor of a curing system at a rotational speed, the at least one rotor comprising at least one magnet; and passing a coated metal strip through the curing system at a strip speed such that the coated metal strip is adjacent to the at least one rotor, generating a current in the coated metal strip and a moving magnetic field in the coated metal strip to heat the coated metal strip; wherein the distance between the coated metal strip and the at least one rotor, the rotational speed, the strength of the at least one magnet, and the strip speed are selected to cure the coating of the coated metal strip within a predetermined time.

[0271] Example 67 is the method of example 66, wherein the distance between the metal strip and the at least one rotor is between about 15 millimeters and about 300 millimeters.

[0272] Example 68 is the method of example 66 or 67, wherein the rotation speed is at least 200 revolutions per minute (RPM).

[0273] Example 69 is the process of Examples 66-68, wherein the strip speed is from about 20 meters / minute to about 400 meters / minute.

[0274] Example 70 is the process of Examples 66-69, wherein the heating rate of the coated metal strip is from about 1° C. / sec to about 150° C. / sec.

[0275] Example 71 is the method of Examples 66-70, wherein the coated metal strip is heated to a temperature of up to 600° C. for a predetermined period of time.

[0276] Example 72 is the method of examples 66-71, wherein rotating at least one rotor includes rotating a plurality of rotors, and passing the coated metal strip through the curing system includes passing the coated metal strip adjacent to the plurality of rotors.

[0277] Example 73 is the method of example 72, wherein rotating the rotors includes rotating a first subset of the plurality of rotors in a first direction and rotating a second subset of the plurality of rotors in a second direction opposite the first direction, wherein the first subset of the plurality of rotors is positioned adjacent to a first surface of the coated metal strip passing through the hardening system and the second subset of the plurality of rotors is positioned adjacent to a second surface of the coated metal strip passing through the hardening system.

[0278] Example 74 is the method of example 73, further comprising individually controlling heating zones associated with one or more subsets of the plurality of rotors.

[0279] Example 75 is the method of example 74, in which individually controlling the heating zones associated with one or more subsets of the plurality of rotors includes controlling a distance between one or more subsets of the plurality of rotors and a first surface of the coated metal strip passing through the hardening system and between a second subset of the plurality of rotors and a second surface of the coated metal strip passing through the hardening system, and controlling a rotational speed of the one or more subsets of the plurality of rotors and the second subset of the plurality of rotors.

[0280] Example 76 is the method of examples 66-75, further comprising directing magnetic flux generated from the rotating rotor to a surface of the metal strip to concentrate heat generation at the surface of the metal strip.

[0281] Example 77 is a method for heating a heat transfer medium, the method including: rotating a rotor having at least one rotating magnet in a curing chamber; generating heat from the rotating rotor by generating a moving magnetic field in the heat transfer medium that induces a current in the heat transfer medium to heat the heat transfer medium; passing the heat transfer medium adjacent to the rotating rotor in the curing chamber to heat the heat transfer medium; and transporting the heated heat transfer medium from the curing chamber to an area remote from the curing chamber.

[0282] Example 78 is the method of example 77, wherein rotating the rotating rotor comprises rotating the rotating rotor at a speed of at least 1,300 revolutions per minute (RPM).

[0283] Example 79 is the method of example 77 or 78, wherein the heat transfer medium comprises water, liquid silicon, air, gas, oil, or other phase change material.

[0284] Example 80 is a heating system comprising a magnetic heating device for heating a metal strip moving in a downstream direction, the magnetic heating device comprising one or more heaters for inducing a tailored temperature profile in the metal strip, the one or more heaters comprising at least one magnetic rotor, each of the at least one magnetic rotor including at least one magnetic source and rotatable about an axis of rotation to generate a varying magnetic field through the metal strip.

[0285] Example 81 is the heating system of Example 80, where the adjusted temperature profile is a laterally uniform temperature profile.

[0286] Example 82 is the heating system of example 80 or 81, wherein one or more of the at least one magnetic rotor has a tailored magnetic flux profile to facilitate inducing a tailored temperature profile in the metal strip.

[0287] Example 83 is the heating system of examples 80-82, wherein the at least one magnetic rotor includes a first magnetic rotor positionable relative to a second magnetic rotor to facilitate inducing a tailored temperature profile within the metal strip.

[0288] Example 84 is the heating system of example 83, wherein the rotation axis of the first magnetic rotor is parallel to the rotation axis of the second magnetic rotor, and at least one of the first magnetic rotor and the second magnetic rotor is laterally offset by an offset distance from the centerline of the metal strip.

[0289] Example 85 is the heating system of example 84, further comprising a controller operably coupled to the actuator that controls the offset distance.

[0290] Example 86 is the heating system of examples 80-85, wherein the at least one magnetic rotor includes a first magnetic rotor and a second magnetic rotor, and the second magnetic rotor is positioned downstream of the first magnetic rotor.

[0291] Example 87 is the heating system of Examples 80 to 86, further comprising an auxiliary heating element positioned adjacent to the metal article and between an edge of the metal article and a lateral centerline of the metal article to facilitate one or more heaters inducing a tailored temperature profile within the metal strip.

[0292] Example 88 is the heating system of Examples 80-87, wherein the magnetic heating device further comprises a deflector positionable to adjust the distance between at least a portion of the metal strip and one or more heaters to facilitate inducing a regulated temperature profile.

[0293] Example 89 is the heating system of Examples 80-88, wherein one or more rotation axes of the at least one magnetic rotor are perpendicular to the downstream direction and parallel to the lateral width of the metal strip.

[0294] Example 90 is the heating system of examples 80-89, wherein one or more magnetic sources of the at least one magnetic rotor include a permanent magnet rotatable about an axis of rotation.

[0295] Example 91 is a heating system of Examples 80 to 90, wherein the magnetic heating device additionally comprises one or more magnetic flux guides positioned adjacent to the at least one magnetic rotor to redirect at least a portion of the magnetic flux from the at least one magnetic rotor to facilitate inducing a regulated temperature profile.

[0296] Example 92 is the heating system of Examples 80-91, further comprising a sensor positioned to measure the temperature or tension of the metal article and a controller coupled to the sensor to receive the sensor signal, the controller coupled to an actuator associated with the magnetic heating device to provide feedback control in response to the sensor signal, and the actuator configured to control the magnetic flux passing through the metal article.

[0297] Example 93 is a method for heating metal, comprising: moving a metal article in a downstream direction; and inducing a tailored temperature profile in the metal article by one or more heaters of a magnetic heating device, wherein the one or more heaters comprise at least one magnetic rotor; and wherein inducing the tailored temperature profile comprises rotating a magnetic source of the at least one magnetic rotor about an axis of rotation of the at least one magnetic rotor to generate a varying magnetic field through the metal article.

[0298] Example 94 is the method of example 93, wherein inducing a tailored temperature profile includes inducing a laterally uniform temperature profile.

[0299] Example 95 is the method of example 93 or 94, wherein the at least one magnetic rotor comprises a magnetic rotor having a tuned magnetic flux profile, and inducing the tuned temperature profile includes rotating the magnetic rotor having the tuned magnetic flux profile to generate the tuned, changing magnetic field.

[0300] Example 96 is the method of examples 93-95, wherein inducing the adjusted temperature profile includes rotating the first magnetic rotor and the second magnetic rotor, and the first magnetic rotor and the second magnetic rotor are positioned relative to one another to facilitate inducing the adjusted temperature profile in the metal article.

[0301] Example 97 is the method of example 96, wherein inducing the adjusted temperature profile includes rotating a first magnetic rotor about a first axis of rotation and rotating a second magnetic rotor about a second axis of rotation that is parallel to the first axis of rotation, and at least one of the first magnetic rotor and the second magnetic rotor is laterally offset from the centerline of the metal article by an offset distance.

[0302] Example 98 is the method of example 97, wherein inducing the adjusted temperature profile further comprises controlling the offset distance.

[0303] Example 99 is the method of examples 93-98, wherein inducing the adjusted temperature profile includes rotating a first magnetic rotor and a second magnetic rotor, the second magnetic rotor being located downstream of the first magnetic rotor.

[0304] Example 100 is the method of examples 93-99, wherein the one or more heaters further comprise auxiliary heating elements positioned adjacent to the metal article and between an edge of the metal article and a lateral centerline of the metal article, and wherein inducing the adjusted temperature profile further comprises applying heat to the metal article from the auxiliary heating elements.

[0305] Example 101 is the method of examples 93-100, wherein inducing the adjusted temperature profile further includes actuating a deflector to adjust a distance between at least a portion of the metal article and the one or more heaters.

[0306] Example 102 is the method of Examples 93-101, wherein the axis of rotation of the at least one magnetic rotor is perpendicular to the downstream direction and parallel to the lateral width of the metal article.

[0307] Example 103 is the method of examples 93-102, wherein the magnetic source of at least one magnetic rotor includes a permanent magnet.

[0308] Example 104 is the method of examples 93-103, wherein inducing the adjusted temperature profile further includes redirecting at least a portion of the magnetic flux from the at least one magnetic rotor to facilitate generating a varying magnetic field through the metal article.

[0309] Example 105 is the method of Examples 93-104, further comprising measuring a temperature or tension of the metal article with a sensor to generate a sensor signal, wherein inducing the adjusted temperature profile further comprises dynamically providing feedback control of the magnetic heating device based on the sensor signal, and wherein dynamically providing feedback control comprises at least one of manipulating the changing magnetic field and manipulating a position of the metal article relative to the changing magnetic field.

[0310] Example 106 is a metal processing system comprising: a metal piece processing facility for processing a moving metal strip; and a magnetic heating device for heating the moving metal strip, wherein the magnetic heating device includes one or more heaters for inducing a controlled temperature profile within the metal strip; the one or more heaters include at least one magnetic rotor, each of the at least one magnetic rotor including at least one magnetic source and rotatable about an axis of rotation to generate a varying magnetic field through the metal strip; and the magnetic heating device is positioned upstream, downstream, or within the metal piece processing facility.

[0311] Example 107 is the metal processing system of example 106, wherein the metal strip processing equipment is a continuous caster for casting moving metal strip.

[0312] Example 108 is the metal processing system of examples 106 or 107, wherein the magnetic heating device is positioned upstream of the metal strip processing equipment to elevate the temperature of the moving metal strip.

[0313] Example 109 is the metal processing system of Examples 106-108, wherein the adjusted temperature profile is a laterally uniform temperature profile.

[0314] Example 110 is the metal processing system of Examples 106-109, including at least one from the group consisting of: a magnetic rotor having a tailored magnetic flux profile to facilitate the magnetic heating device inducing a tailored temperature profile in the metal article; a first magnetic rotor and a second magnetic rotor, where at least one of the first magnetic rotor and the second magnetic rotor is laterally offset from a centerline of the metal strip; a second magnetic rotor positioned downstream of the first magnetic rotor; an auxiliary heating element positioned adjacent to the metal strip and between an edge of the metal strip and the lateral centerline of the metal strip; and a deflector positionable to adjust a distance between at least a portion of the metal article and the one or more heaters.

[0315] Example 111 is the metal processing system of Examples 106-110, further comprising an idler roller coupled to a support movable between a first position and a second position, wherein the moving metal strip passes adjacent to the one or more heaters of the magnetic heating device when the support is in the first position and the moving metal strip passes away from the one or more heaters of the magnetic heating device when the support is in the second position.

Claims

1. 1. A heating system comprising:

1. A heating system comprising: a magnetic heating device for heating a metal article moving in a downstream direction, the magnetic heating device comprising one or more heaters for inducing a tailored temperature profile within the metal article, the one or more heaters comprising at least one magnetic rotor, each of the at least one magnetic rotor including at least one magnetic source and rotatable about an axis of rotation to generate a varying magnetic field through the metal article.

2. The heating system of claim 1 , wherein the regulated temperature profile is a laterally uniform temperature profile.

3. 10. The heating system of claim 1, wherein one or more of the at least one magnetic rotor has a tailored magnetic flux profile to facilitate inducing the tailored temperature profile within the metal article.

4. 10. The heating system of claim 1, wherein the at least one magnetic rotor comprises a first magnetic rotor positionable relative to a second magnetic rotor to facilitate inducing the tailored temperature profile within the metal article.

5. 5. The heating system of claim 4, wherein an axis of rotation of the first magnetic rotor is parallel to an axis of rotation of the second magnetic rotor, and at least one of the first magnetic rotor and the second magnetic rotor is laterally offset from a centerline of the metal article by an offset distance.

6. The heating system of claim 5 , further comprising a controller operably coupled to an actuator that controls the offset distance.

7. The heating system of claim 1 , wherein the at least one magnetic rotor includes a first magnetic rotor and a second magnetic rotor, the second magnetic rotor being positioned downstream from the first magnetic rotor.

8. 10. The heating system of claim 1, wherein the one or more heaters further comprise auxiliary heating elements positioned adjacent the metal article and between an edge of the metal article and a lateral centerline of the metal article to facilitate inducing the tailored temperature profile within the metal article.

9. 10. The heating system of claim 1, wherein the magnetic heating device further comprises a deflector positionable to adjust a distance between at least a portion of the metal article and the one or more heaters to facilitate inducing the tailored temperature profile.

10. The heating system of claim 1 , wherein the rotational axis of one or more of the at least one magnetic rotor is perpendicular to the downstream direction and parallel to a lateral width of the metal article.

11. The heating system of claim 1 , wherein the magnetic source of one or more of the at least one magnetic rotor includes a permanent magnet rotatable about the axis of rotation.

12. 10. The heating system of claim 1, wherein the magnetic heating device additionally comprises one or more magnetic flux guides positioned adjacent to the at least one magnetic rotor to redirect at least a portion of magnetic flux from the at least one magnetic rotor to facilitate inducing the tailored temperature profile.

13. a sensor positioned to measure the temperature or tension of the metal article; 10. The heating system of claim 1, further comprising: a controller coupled to the sensor to receive a sensor signal, the controller coupled to an actuator associated with the magnetic heating device to provide feedback control in response to the sensor signal, the actuator configured to control magnetic flux passing through the metal article.

14. 1. A method for heating a metal, comprising: moving a metal article in a downstream direction; inducing a tailored temperature profile in the metal article by one or more heaters of a magnetic heating device, the one or more heaters comprising at least one magnetic rotor, and inducing the tailored temperature profile comprises rotating a magnetic source of the at least one magnetic rotor about an axis of rotation of the at least one magnetic rotor to generate a varying magnetic field through the metal article.

15. The method of claim 14 , wherein inducing the tailored temperature profile comprises inducing a laterally uniform temperature profile.

16. 15. The method of claim 14, wherein the at least one magnetic rotor comprises a magnetic rotor having a tailored magnetic flux profile, and wherein inducing the tailored temperature profile comprises rotating the magnetic rotor having the tailored magnetic flux profile to generate a tailored, changing magnetic field.

17. 15. The method of claim 14, wherein inducing the tailored temperature profile comprises rotating a first magnetic rotor and a second magnetic rotor, the first magnetic rotor and the second magnetic rotor being positioned relative to one another to facilitate inducing the tailored temperature profile within the metal article.

18. 18. The method of claim 17, wherein inducing the tailored temperature profile comprises rotating a first magnetic rotor about a first axis of rotation and rotating a second magnetic rotor about a second axis of rotation that is parallel to the first axis of rotation, wherein at least one of the first magnetic rotor and the second magnetic rotor is laterally offset from a centerline of the metal article by an offset distance.

19. The method of claim 18 , wherein inducing the adjusted temperature profile further comprises controlling the offset distance.

20. 15. The method of claim 14, wherein inducing the adjusted temperature profile includes rotating a first magnetic rotor and a second magnetic rotor, the second magnetic rotor being located downstream from the first magnetic rotor.

21. 15. The method of claim 14, wherein the one or more heaters further comprise a supplemental heating element positioned adjacent to the metal article and between an edge of the metal article and a lateral centerline of the metal article, and wherein inducing the adjusted temperature profile further comprises applying heat to the metal article from the supplemental heating element.

22. 15. The method of claim 14, wherein inducing the adjusted temperature profile further comprises actuating a deflector to adjust a distance between at least a portion of the metal article and the one or more heaters.

23. The method of claim 14 , wherein the axis of rotation of the at least one magnetic rotor is perpendicular to the downstream direction and parallel to a lateral width of the metal article.

24. The method of claim 14 , wherein the magnetic source of the at least one magnetic rotor comprises a permanent magnet.

25. 15. The method of claim 14, wherein inducing the tailored temperature profile further comprises redirecting at least a portion of magnetic flux from the at least one magnetic rotor to facilitate generating the changing magnetic field through the metal article.

26. 15. The method of claim 14, further comprising measuring a temperature or tension of the metal article with a sensor to generate a sensor signal, and wherein inducing the adjusted temperature profile further comprises dynamically providing feedback control of the magnetic heating device based on the sensor signal, and wherein dynamically providing feedback control comprises at least one of manipulating the changing magnetic field and manipulating a position of the metal article relative to the changing magnetic field.

27. passing a metal strip through a first gap defined between an upper magnetic rotor and a lower magnetic rotor of a first magnetic rotor set; passing the metal strip through a second gap defined between an additional upper magnetic rotor and an additional lower magnetic rotor of a second magnetic rotor set; rotating the first magnetic rotor set at a first speed to induce a first varying magnetic field in the first gap to heat the metal strip; rotating the second magnetic rotor set at a second speed to induce a second changing magnetic field in the second gap to heat the metal strip; and controlling tension in the metal strip, wherein controlling tension comprises adjusting at least one of the first gap, the second gap, the first speed, and the second speed.

28. 28. The method of claim 27, further comprising taking measurements of the metal strip, and controlling the tension comprises making adjustments based on the measurements.

29. 28. The method of claim 27, further comprising adjusting a longitudinal position of at least one of the first magnetic rotor set and the second magnetic rotor set.

30. 28. The method of claim 27, further comprising adjusting a lateral position of at least one magnetic rotor of at least one of the first magnetic rotor set and the second magnetic rotor set.

31. 28. The method of claim 27, wherein controlling tension in the metal strip includes using the second magnetic rotor set to offset tension changes induced by the first magnetic rotor set.

32. 28. The method of claim 27, wherein controlling the tension in the metal strip comprises adjusting at least one of the first gap and the second gap.

33. A magnetic rotor having a regulated magnetic flux, A central axis of rotation; one or more magnetic sources rotatable about the central axis of rotation; a magnetic flux profile based on the one or more magnetic sources, wherein the magnetic flux profile is non-uniform along a length of the magnetic rotor.

34. 34. The magnetic rotor of claim 33, further comprising one or more magnetic flux guides, wherein the one or more magnetic sources exhibit an initial magnetic flux profile, and the one or more magnetic flux guides are positioned to deflect at least a portion of the initial magnetic flux profile to exhibit a non-uniform magnetic flux profile.

35. 34. The magnetic rotor of claim 33, wherein the one or more magnetic sources vary in strength over the length of the magnetic rotor to present the non-uniform magnetic flux profile.

36. 34. The magnetic rotor of claim 33, further comprising one or more sleeves positioned around at least a portion of the one or more magnetic sources, the one or more magnetic sources exhibiting an initial magnetic flux profile, the one or more sleeves being positioned to deflect at least a portion of the initial magnetic flux profile to exhibit a non-uniform magnetic flux profile.

37. 34. The magnetic rotor of claim 33, wherein the non-uniform magnetic flux profile reaches a maximum amount of magnetic flux between a center of the length of the magnetic rotor and one end of the magnetic rotor.

38. 34. The magnetic rotor of claim 33, wherein the non-uniform magnetic flux profile reaches a maximum amount of magnetic flux at locations between the center of the length of the rotor and each end of the rotor.

39. rotating at least one rotor of a curing system at a rotational speed, said at least one rotor comprising at least one magnet; and passing a coated metal strip through the hardening system at a strip speed such that the coated metal strip is adjacent to the at least one rotor, thereby inducing a current in the coated metal strip and generating a moving magnetic field in the coated metal strip to heat the coated metal strip, wherein the distance between the coated metal strip and the at least one rotor, the rotational speed, the strength of the at least one magnet, and the strip speed are selected to harden the coating of the coated metal strip within a predetermined time.

40. 40. The method of claim 39, wherein the distance between the metal strip and the at least one rotor is between about 15 millimeters and about 300 millimeters.

41. 40. The method of claim 39, wherein the rotational speed is at least 200 revolutions per minute (RPM).

42. 40. The method of claim 39, wherein the strip speed is from about 20 meters / minute to about 400 meters / minute.

43. 40. The method of claim 39, wherein the heating rate of the coated metal strip is from about 1° C. / sec to about 150° C. / sec.

44. 40. The method of claim 39, wherein the coated metal strip is heated to a temperature of up to 600°C within the predetermined period of time.

45. 40. The method of claim 39, wherein rotating the at least one rotor comprises rotating a plurality of rotors, and passing the coated metal strip through the hardening system comprises passing the coated metal strip adjacent to each of the plurality of rotors.

46. 46. ​​The method of claim 45, wherein rotating the rotors comprises rotating a first subset of the plurality of rotors in a first direction and rotating a second subset of the plurality of rotors in a second direction opposite the first direction, wherein the first subset of the plurality of rotors is positioned adjacent to a first surface of the coated metal strip passing through the hardening system and the second subset of the plurality of rotors is positioned adjacent to a second surface of the coated metal strip passing through the hardening system.

47. 47. The method of claim 46, further comprising individually controlling heating zones associated with one or more subsets of the plurality of rotors.

48. Individually controlling heating zones associated with one or more subsets of the plurality of rotors; controlling a distance between the one or more subsets of the plurality of rotors and the first surface of the coated metal strip passing through the hardening system, and a distance between the second subset of the plurality of rotors and the second surface of the coated metal strip passing through the hardening system; and controlling the rotational speed of the one or more subsets of the plurality of rotors and the second subset of the plurality of rotors.

49. 40. The method of claim 39, further comprising directing magnetic flux generated from the rotating rotor toward a surface of the metal strip to concentrate heat generation at the surface of the metal strip.

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