Transverse magnetic flux induction heating device for heating flat product

Abstract

To provide an induction heating device and a method for using the same.SOLUTION: A device includes two poles, each pole includes a pair of spaced apart coils, and at least one of a spacing between the poles and the pole pitch is adjustable to control the density of power transmitted in a width direction of a workpiece. In some embodiments, movable magnetic flux shields are also adjusted to control the density of power transmitted along edge portions of the workpiece.SELECTED DRAWING: Figure 4

Description

Background Art

[0001] Induction heaters are suitable for heating various thicknesses and widths of conductive continuous flat strip / plate products as shown in FIG. 1. Conventional induction heating has used a solenoid-type coil wound around a strip or plate as shown in FIG. 2. FIG. 1 shows the heating of the bandwidth on the plate. FIG. 2 shows the state of a conventional solenoid coil wound around a plate. When an alternating current is applied to the coil, an electromagnetic field is generated, and eddy currents are induced around the plate surface reflecting the current in the coil, causing Joule heating of the plate. The solenoid coil heating system has several drawbacks and is not a desirable choice for this particular application. The first problem is that the thinner the plate, the higher the induction frequency required to efficiently inductively couple. At the same time, a frequency that is not so high needs to be selected so that the ends of the plate do not overheat or the surface does not overheat before the core of the plate experiences a temperature rise. For this reason, a very high frequency is required to heat a thin plate, and a low frequency is required to heat a thick plate. There may be a need for a wide frequency range from a single power source, or there may be a need for multiple power sources with different frequencies for each plate thickness to be heated. In such a situation, induction heating may not be cost-effective. Furthermore, in the case of very thin plates, the frequency required to efficiently heat the strip by conventional solenoid coil induction technology becomes higher than the reasonably available frequencies, and induction heating may not be an option.

[0002] Transverse flux induction heating is known. For example, U.S. Patent No. 9,462,641, which is hereby incorporated by reference in its entirety, discloses a transverse induction heating device that can be used to heat strips of sheet material. Current transverse induction heating devices lack the ability to accurately and precisely control the power density transmitted in the length direction of the sheet, and in many cases, either the edge portion of the strip overheats or the central portion of the strip underheats. Further, current transverse induction heating devices generally can only accept a narrow range of dimensions of the strip material. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0003] The present disclosure provides an induction heating device and method of use, the device including two poles, each pole including a pair of spaced-apart coils with a gap therebetween, where at least one of the gap between the poles and the pole pitch is adjustable to control the power density transmitted in the width direction of the workpiece. In some embodiments, a movable magnetic flux shield is also adjusted to control the power density transmitted along the edge portion of the workpiece.

[0004] According to one aspect of the present disclosure, a transverse flux induction coil assembly for induction heating at least a portion of an associated flat workpiece moving along a process direction relative to the transverse flux electrical induction coil assembly, the associated workpiece having opposing first and second workpiece surfaces and first and second workpiece edges, the induction heating device including a first planar coil and a second planar coil disposed in a first common plane spaced from and facing the first workpiece surface, extending between the first and second workpiece edges, and electrically coupled in series. The first planar coil and the second planar coil are spaced apart on the same plane, and at least one of the first planar coil and the second planar coil is movable within the common plane and can change the gap therebetween.

[0005] At least one of the first planar coil and the second planar coil is adjustable to change the coil pitch. The first planar coil may be formed from a first outward leg and a first return leg that extend in a common direction and are spaced apart. The first outward leg and the first return leg may be physically and electrically coupled to a first end rail, and at least one of the first outward leg and the first return leg may be movably attached to the first end rail so that the first outward leg and the first return leg move toward and away from each other to change the coil pitch of the first planar coil. The second planar coil may be formed from a second outward leg and a second return leg that extend in a common direction and are spaced apart. The second outward leg and the second return leg may be physically and electrically coupled to a second end rail, and at least one of the second outward leg and the second return leg may be movably attached to the second end rail so that the second outward leg and the second return leg move toward and away from each other to change the coil pitch of the second planar coil.

[0006] The first planar coil and the second planar coil may each be coupled to a first common rail, and at least one of the first coil or the second coil is movably supported on the first common rail toward or away from the other of the first or second coil. The first return leg of the first coil and the second outward leg of the second coil may be coupled to the first common rail, and at least one of the first return leg and the second outward leg is movable relative to the common rail to change the distance between the first planar coil and the second planar coil.

[0007] The assembly is arranged on a second common plane spaced apart from the second workpiece surface, extends between the first and second workpiece edges, and can further include a third planar coil and a fourth planar coil electrically coupled in series with the first planar coil and the second planar coil. The third planar coil and the fourth planar coil are separated and on the same plane within the second common plane, are movable within the second common plane, and vary the spacing therebetween. The third planar coil and the fourth planar coil are spaced apart and arranged on the same plane within the second common plane, and at least one of the third planar coil and the fourth planar coil is movable within the second common plane and can vary the spacing therebetween. At least one of the third planar coil and the fourth planar coil is adjustable to change the coil pitch.

[0008] The third planar coil is formed from a third outward leg and a third return leg that extend in a common direction and are spaced apart, and the third outward leg and the third return leg are physically and electrically coupled to a third end rail. At least one of the third outward leg and the third return leg can be movably attached to the third end rail so that the third outward leg and the third return leg move towards and away from each other to change the coil pitch of the third planar coil. The fourth planar coil is formed from a fourth outward leg and a fourth return leg that extend in a common direction and are spaced apart, and the fourth outward leg and the fourth return leg are physically and electrically coupled to a fourth end rail. At least one of the fourth outward leg and the fourth return leg can be movably attached to the fourth end rail so that the fourth outward leg and the fourth return leg move towards and away from each other to change the coil pitch of the fourth planar coil.

[0009] The third planar coil and the fourth planar coil may each be coupled to a second common rail, and at least one of the third planar coil or the fourth planar coil is movably supported on the second common rail so as to move toward or away from the other of the third or fourth planar coils. The third return leg of the third coil and the fourth outward leg of the fourth coil may be coupled to the second common rail, and at least one of the third return leg and the fourth outward leg is movable relative to the second common rail to vary the distance between the third planar coil and the fourth planar coil. The return leg of the second planar coil and the outward leg of the third planar coil may be rigidly coupled.

[0010] The assembly may further comprise at least one magnetic flux shield disposed at a distance between the first common plane and the first workpiece surface facing at least one of the first and second workpiece edges. At least one of the at least one magnetic flux shield is movable in the lateral direction of the associated workpiece.

[0011] According to another aspect, a transverse flux induction coil assembly for inductively heating at least a portion of an associated flat workpiece moving along a process direction relative to the transverse flux electric induction coil assembly, the associated workpiece having opposing first and second workpiece surfaces and first and second workpiece edges, disposed in a first common plane spaced from the first workpiece surface, extending between the first and second workpiece edges, and comprising a first planar coil and a second planar coil electrically coupled in series, at least one of the first planar coil and the second planar coil being adjustable to vary the coil pitch.

[0012] The first planar coil is formed from a first outward leg and a first return leg that extend in a common direction and are spaced apart, and the first outward leg and the first return leg are physically and electrically coupled to a first end rail. At least one of the first outward leg and the first return leg can be movably attached to the first end rail so that the first outward leg and the first return leg move toward and away from each other to change the coil pitch of the first planar coil. The second planar coil is formed from a second outward leg and a second return leg that extend in a common direction and are spaced apart, and the second outward leg and the second return leg are physically and electrically coupled to a second end rail. At least one of the second outward leg and the second return leg can be movably attached to the second end rail so that the second outward leg and the second return leg move toward and away from each other to change the coil pitch of the second planar coil.

[0013] The assembly is disposed in a second common plane spaced from and facing the second workpiece surface, and can further include a third planar coil and a fourth planar coil that extend between the first and second workpiece edges and are electrically coupled in series with the first planar coil and the second planar coil. At least one of the third planar coil and the fourth planar coil is adjustable to change the pitch of the coil. The third planar coil is formed from a third outward leg and a third return leg that extend in a common direction and are spaced apart, and the third outward leg and the third return leg are physically and electrically coupled to a third end rail. At least one of the third outward leg and the third return leg can be movably attached to the third end rail so that the third outward leg and the third return leg move toward and away from each other to change the coil pitch of the third planar coil. The fourth planar coil is formed from a fourth outward leg and a fourth return leg that extend in a common direction and are spaced apart, and the fourth outward leg and the fourth return leg are physically and electrically coupled to a fourth end rail. At least one of the fourth outward leg and the fourth return leg can be movably attached to the fourth end rail so that the fourth outward leg and the fourth return leg move toward and away from each other to change the coil pitch of the fourth planar coil.

[0014] According to another aspect, a method of inductively heating a related strip workpiece includes supplying current to a transverse flux electric induction coil assembly to inductively heat at least a portion of the related strip workpiece that moves along a process direction relative to the transverse flux electric induction coil assembly, the related strip workpiece having opposing first and second workpiece surfaces and first and second workpiece edges, the induction heating device includes a first planar coil and a second planar coil that are disposed in a first common plane facing and spaced from the first workpiece surface, extend between the first and second workpiece edges, and are electrically coupled in series, the first planar coil and the second planar coil being spaced apart on the same plane, at least one of the first planar coil and the second planar coil being movable within the common plane to change the spacing therebetween and adjust the spacing between the first coil and the second coil. At least one of the first planar coil and the second planar coil can be adjustable to change the pitch of the coil and further include adjusting the pitch of at least one coil.

Brief Description of the Drawings

[0015]

Figure 1

[0016]

Figure 2

[0017]

Figure 3

[0018]

Figure 4

[0019]

Figure 5

[0020]

Figure 6

[0021]

Figure 7a

[0022]

Figure 7b

[0023]

Figure 8a

[0024]

Figure 8b

[0025]

Figure 9a

[0026]

Figure 9b

[0027]

Figure 10a

[0028]

Figure 10b

[0029]

Figure 11a

[0030]

Figure 11b

[0031]

Figure 12

[0032]

Figure 13

[0033]

Figure 14

[0034]

Figure 15

[0035]

Figure 16

[0036]

Figure 17

[0037]

Figure 18

[0038]

Figure 19

[0039]

Figure 20

[0040]

Figure 21

[0041]

Figure 22

[0042]

Figure 23

[0043] In the drawings, like reference numerals refer to like elements throughout, and various features are not necessarily drawn to scale. Also, the term "couple" or "couples" includes an indirect or direct, electrical or mechanical connection or combinations thereof. For example, if a first device couples to or is coupled with a second device, the connection may be through a direct electrical connection or through an indirect electrical connection via one or more intervening devices and connections. Hereinafter, one or more operating characteristics of various circuits, systems, and / or components will be described in relation to their functions, which may in some cases be the result of the configuration and / or interconnection of various structures when the circuit is powered on and operating.

[0044] Due to the problems of solenoid induction heating as described above, especially for very thin strips or plates, transverse flux technology has been used instead of conventional solenoid heating technology. Many different transverse flux designs have been developed. Many of these designs are very complex and high-maintenance items, requiring many moving parts. In one example, a flat strip / plate is heated using a transverse flux design that can select either a single frequency or a small variation in frequency and utilize the frequency range available from a single power source to efficiently heat all plate / strip sizes. It is desirable to heat any part of the plate without overheating at the lowest possible frequency. A second drawback of using a solenoid coil is that since the coil wraps around the plate, it becomes difficult to handle the plate from heating to the bending process. In the case of a strip, the coil cannot be removed while keeping the continuous strip inside. When the workpiece is very wide, a general in-line seam annealing coil cannot be designed to heat the entire width uniformly. Therefore, it would be beneficial to use an induction heating coil configuration that does not surround the plate / strip to be heated.

[0045] Referring also to FIG. 3-5, one aspect of the present disclosure provides a transverse flux coil designed such that the strip S passes between a pair of wide oval coils C generically referred to as poles P, as shown in FIG. 3. FIG. 3 shows a setup of a simple transverse flux induction heating coil showing the configuration of the pole P in relation to the strip. FIG. 4 shows the applied current to the wide oval coil C. FIG. 5 shows the flow of current generated on the strip surface (typical respective surfaces). Generally, although not a strict requirement for all possible implementations, the coils C are arranged directly side by side with each other or as mirror images of each other on both sides of the strip. The coils C are electrically connected in series with each other such that the currents in the coils C on both sides of the strip are electrically in phase with each other, as shown in FIG. 4. As a result, an induced current flows through the strip as shown in FIG. 5.

[0046] Referring also to FIGS. 6, 7a and 7b, in one example, a pair of wide oval transverse flux coils C are provided on each surface of the strip to form at least two poles P1 and P2. Each coil C is electrically connected in series and in phase with respect to each surface, operating like a split return inductor. FIG. 7b shows the configuration and current flow of a typical split return inductor. FIGS. 7a and 7b each show that the coil configuration of the present disclosure (FIG. 7a) is designed to operate inductively like a conventional split return inductor (FIG. 7b).

[0047] FIGS. 8a and 8b each show the current generated in the strip using a split return transverse flux inductor (FIG. 8a) and the power density generated in the strip by the split return transverse flux inductor (FIG. 8b). In a split return inductor, typically, the main heating of the strip occurs along the middle part of the inductor assembly, and the current is twice / substantially twice that of the outer legs of the inductor. Since power is proportional to the square of the current × resistance (P = I 2·R), if the current density doubles along the intermediate conductor of the pole pair, the power generated in the strip quadruples. In a typical split return design transverse flux inductor, the induced current is similar to that shown in Fig. 8a, and as a result, the relative power density distribution within the strip as shown in Fig. 8b is obtained.

[0048] Figs. 9a and 9b show that, as shown in Fig. 7a, by adjusting the space between poles P1 and P2 of the transverse inductor, the heating pattern in the width direction of the strip can be changed. In this example, as shown in Figs. 9a and 9b, a function is provided to adjust the spacing SP between the respective center legs of the wide oval coil C. This function enables adjustment of the power density across the entire strip, and as a result, adjustment of the thermal profile across the entire strip.

[0049] As further shown in Figs. 10a, 10b, 11a, and 11b, a further aspect provides one or more magnetic flux shields SH made of a highly conductive material. As shown in Figs. 10(a) and 10(b), the shield SH is disposed between the strip to be heated and the coil C. The shield SH is movable (e.g., along the length direction of the plate shown in Fig. 1) and is used to shield the edges of the strip from the electromagnetic field to minimize overheating at the edges of the strip. The shield SH is adjustable to provide the same function for narrower strips, as shown in Figs. 11(a) and 11(b). Figs. 10a and 10b show an adjustable magnetic flux shield SH provided to control the strip edge temperature. Figs. 11a and 11b show that the magnetic flux shield SH is adjustable to perform the same function with narrower strips.

[0050] Also, referring to FIG. 12, in a particular example, the disclosed concept can also include a stacked magnetic lamination sheet LS disposed outside the coil away from the strip, as shown in FIG. 12. This lamination helps improve the efficiency of the inductor and minimize the external fringing field of coil C that can induce heat in other conductive objects outside the inductor. FIG. 12 shows an inductor assembly shown by a stack of magnetic laminations LS disposed outside the coil assembly.

[0051] FIGS. 13 through 20 generally identified by reference numeral 50, having two poles 52A and 52B, and capable of all of the above adjustments including adjustment of the split return gap, adjustment of the pole pitch of one or both poles, and / or adjustment of the position of one or more magnetic flux shields, thereby corresponding to more uniform heating of a wide range of strip widths within a single induction heating assembly, show various aspects of an exemplary embodiment of the induction heating assembly of the present disclosure.

[0052] After introducing the general components of the induction heating assembly 50 in the order of the flow of current through the assembly, the function of the induction heating assembly 50 will be described. The flow of current through the assembly is indicated by arrow A in FIG. 13. The pole 52A includes a first (proximal) coil C1 having an outward leg 54 with a first (proximal) end 56 that receives current from a suitable power source (not shown in the figure). As used herein, with respect to the legs of the coil, the terms proximal end and distal end are taken in the direction of the flow of current, along with the proximal end that refers to the end of the leg that receives current and the distal end that refers to the end of the leg from which the current exits the leg. Thus, the leg 54 is movably supported and electrically coupled at a second (distal) end 58 by an end rail or guide member 60. The rail 60 is conductive or includes a conductive structure that electrically couples the leg 54 and the return leg 62. The distal end of the return leg 62 is movably supported and electrically coupled by a common rail or guide member 64. The common rail 64 is conductive or includes a conductive structure that electrically couples the leg 62 of coil C1 and the outward leg 66 of coil C2. The outward leg 66 is electrically coupled to an end rail or guide 68. The rail 68 is conductive or includes a conductive structure that electrically couples the return leg 70 of coil C2 and the leg 66. Coil C2 is electrically coupled to coil C3 of pole 52B via a connector 74. The outward leg 76 of coil C3 is electrically coupled to an end rail 78. The rail 78 is conductive or includes a conductive structure that electrically couples the outward leg 76 and the return leg 80. The return leg 80 is electrically coupled to a common rail or guide member 82 that electrically couples coil C3 to the outward leg 84 of coil C4. The outward leg 84 is electrically coupled to an end rail 86 that is conductive or includes a conductive structure that electrically couples the return leg 88 of coil C4 and the leg 84. In this description, the term common rail is used with respect to a rail or guide member that couples the coils of adjacent poles, and the term end rail is used with respect to a rail or guide member that couples the outward and return legs of a particular coil.

[0053] As understood herein, coils C1, C2, C3, and C4 are connected in series, and the arrangement of the outward legs and return legs of each coil pair (C1 / C4, C2 / C3) is such that, on each surface of the sheet to be heated, current flows in a common direction through the outward legs of each coil pair and current also flows in a common direction through the return legs of each coil pair.

[0054] Each of the outward legs 54, 66, 76, and 84 is slidably coupled at its distal end to a respective end rail, while each of the return legs 62, 70, 80, and 88 is fixedly coupled at its proximal end to a respective end rail. On the other hand, the outward legs 66 and 84 are slidably coupled at their proximal ends to a respective common rail. Thus, the slide connection of the end rails facilitates bringing the respective outward legs and return legs of the coils closer to or farther from each other to adjust the coil pitch, and the slide connection of the common rails facilitates bringing the poles closer to or farther from each other to adjust the split return gap.

[0055] Referring to FIG. 14, it is understood that the relative movement of the outward legs 54, 66, 76, 84 with respect to the return legs 62, 70, 80, 88 facilitates changing at least one of the split return gap (e.g., the spacing between poles 52A and 52B) and the pole pitch (e.g., the spacing between the outward and return legs of a pole). The slide of the outward legs on the end rails mainly affects the change in the pole pitch, and the slide of the return leg 62 and the outward leg 84 on their respective common rails mainly affects the change in the split return gap.

[0056] Figures 15 - 17 show examples of possible adjustments of the pole pitch and / or the split return gap. In Figure 15, poles 52A and 52B have a first pole pitch and are spaced by a first split return gap. In Figure 16, the pole pitch of poles 52A and 52B is the same as in Figure 15, but the split return gap is reduced by bringing poles 52A and 52B closer together. In Figure 17, the split return gap between poles 52A and 52B is the same as in Figure 16, but the pole pitch of each of poles 52A and 52B is reduced by sliding the outward legs 66, 84 on a common rail. By adjusting the pole pitch and / or the split return gap, by concentrating or dispersing the magnetic flux generated by the coil, it is understood that the assembly can heat a wider range of strip material widths and thicknesses more accurately and / or heat a given strip more uniformly.

[0057] Referring to Figures 18 - 20, an exemplary assembly 50 is shown having a magnetic flux shield SH disposed between coils C1 - C4 and a sheet material SM. The magnetic flux shield SH is generally aligned along end rails and common rails and is generally sized and shaped to cover what is expected to be the longitudinal edge portion of the sheet material in order to prevent overheating of such edges. In Figures 18 and 19, strips of a relatively wide sheet material SM are shown, and in Figure 19 more of the magnetic flux shield SH overlaps the sheet material SM than in Figure 18. In Figure 20, a relatively narrow strip of the sheet material SM is shown, and the magnetic flux shield SH has been moved inward to cover at least a portion of the longitudinal edge of the sheet material SM.

[0058] It should be recognized that a wide range of actuators can be used to make the adjustments described in the previous paragraph, such as linear actuators, servos, etc. In some embodiments, some or all of the adjustments can be made manually. In other examples, various sensors can be used to sense the state of the sheet material, and one or more parameters of the assembly 50 can be adjusted in real time according to the sensed data. For example, by using various thermal sensors, the temperature of the strip can be monitored to identify high or low temperature regions, and the assembly 50 can be adjusted to eliminate or reduce such regions. By using an edge tracking sensor, the edge of the sheet material can be identified and the magnetic flux shield can be placed more accurately.

[0059] Referring to FIGS. 21-23, the effects of the above adjustments, pole pitch, split return gap, and shield position are shown in graph form for a strip of sheet material of a predetermined width. In each graph, the position in the strip width direction is plotted on the X-axis, and the time-averaged relative power density transmitted to the strip is plotted on the Y-axis. In FIG. 21, various pole pitches are graphed, including a wide pole pitch (dotted line), a central pole pitch (dashed line), and a narrow pole pitch (solid line). As can be seen, each line coincides at the center line of the strip and branches towards the ends of the strip, with the wide pole pitch having the greatest transmission of power density to the edge and the narrow pole pitch having the least transmission of power density to the edge. In FIG. 22, various split return gaps are graphed, including a large split return gap (dotted line) and a small split return gap (solid line). As can be seen, each line coincides at the center line of the strip and branches towards the ends of the strip, with the large split return gap resulting in the greatest transmission of power density to the edge portion and the small split return gap resulting in the least transmission of power density to the edge portion. In general, it should be recognized that changes in the pole pitch result in a greater overall change in the transmission of power density compared to changes in the split return gap.

[0060] Therefore, it can be considered that the adjustment of the pole pitch width is a coarse adjustment, and the adjustment of the split return gap is a fine adjustment. Therefore, in practice, first, the pole pitch is set to the width for achieving the baseline power density transmission, and then the split return gap can be used to finely adjust the power density transmission.

[0061] Figure 23 shows the overlap of two different magnetic flux shields, a reduced overlap (dashed line) and an increased gap (solid line). As the overlap decreases, the transmission of power density at the edge of the strip increases. The overlap of the magnetic flux shield is used in relation to the adjustment of the pole pitch and the split return gap, and can be used to finely adjust the power density transmission for a given strip size.

[0062] The described examples are modifiable, and within the scope of the claims, other embodiments are also possible.

Claims

1. A transverse magnetic flux induction coil assembly for inductively heating at least a portion of an associated flat workpiece that moves along a process direction relative to the transverse magnetic flux electric induction coil assembly, The associated workpiece has opposing first and second workpiece surfaces and first and second workpiece edges, The induction heating device, Comprises a first planar coil and a second planar coil, which are arranged in a first common plane facing and spaced from the first workpiece surface, extend between the first and second workpiece edges, and are electrically connected in series, The first planar coil and the second planar coil are spaced apart on the same plane, and at least one of the first planar coil and the second planar coil is movable within the common plane and the distance therebetween can be changed, Transverse magnetic flux induction coil assembly.

2. At least one of the first planar coil and the second planar coil is adjustable to change the coil pitch, The transverse magnetic flux induction coil assembly according to Claim 1.

3. The first planar coil is formed from a first outward leg and a first return leg that extend in a common direction and are spaced apart, the first outward leg and the first return leg are physically and electrically coupled to a first end rail, and at least one of the first outward leg and the first return leg is movably attached to the first end rail so that the first outward leg and the first return leg move towards and away from each other to change the coil pitch of the first planar coil, The second planar coil is formed from a second outward leg and a second return leg that extend in a common direction and are spaced apart, the second outward leg and the second return leg are physically and electrically coupled to a second end rail, and at least one of the second outward leg and the second return leg is movably attached to the second end rail so that the second outward leg and the second return leg move towards and away from each other to change the coil pitch of the second planar coil, The transverse magnetic flux induction coil assembly according to Claim 2.

4. The first planar coil and the second planar coil are each coupled to a first common rail, and at least one of the first coil or the second coil is movably supported on the first common rail towards or away from the other of the first or second coils, The transverse magnetic flux induction coil assembly according to Claim 3.

5. The first return leg of the first coil and the second outward leg of the second coil are coupled to the first common rail, and at least one of the first return leg and the second outward leg is movable relative to the common rail to vary the distance between the first planar coil and the second planar coil. The transverse flux induction coil assembly according to claim 4.

6. Further including a third planar coil and a fourth planar coil disposed in a second common plane spaced apart from and facing the second workpiece surface, extending between the first and second workpiece edges, and electrically coupled in series with the first planar coil and the second planar coil. The transverse flux induction coil assembly according to claim 5.

7. The third planar coil and the fourth planar coil are spaced apart and coplanar within the second common plane, and at least one of the third planar coil and the fourth planar coil is movable within the second common plane to vary the spacing therebetween. The transverse flux induction coil assembly according to claim 6.

8. At least one of the third planar coil and the fourth planar coil is adjustable to change the coil pitch. The transverse flux induction coil assembly according to claim 7.

9. The third planar coil is formed from a third outward leg and a third return leg that extend in a common direction and are spaced apart, the third outward leg and the third return leg being physically and electrically coupled to a third end rail, and at least one of the third outward leg and the third return leg being movably attached to the third end rail such that the third outward leg and the third return leg move towards and away from each other to change the coil pitch of the third planar coil. The fourth planar coil is formed from a fourth outward leg and a fourth return leg that extend in a common direction and are spaced apart, the fourth outward leg and the fourth return leg being physically and electrically coupled to a fourth end rail, and at least one of the fourth outward leg and the fourth return leg being movably attached to the fourth end rail such that the fourth outward leg and the fourth return leg move towards and away from each other to change the coil pitch of the fourth planar coil. The transverse flux induction coil assembly according to claim 8.

10. The third planar coil and the fourth planar coil are each coupled to a second common rail, and at least one of the third planar coil or the fourth planar coil is movably supported on the second common rail so as to move toward or away from the other of the third or fourth planar coils. The transverse flux induction coil assembly according to claim 9.

11. The third return leg of the third coil and the fourth outward leg of the fourth coil are coupled to the second common rail, and at least one of the third return leg and the fourth outward leg is movable relative to the second common rail, changing the distance between the third planar coil and the fourth planar coil. The transverse flux induction coil assembly according to claim 10.

12. The return leg of the second planar coil and the outward leg of the third planar coil are rigidly coupled. The transverse flux induction coil assembly according to claim 11.

13. Further comprising at least one magnetic flux shield disposed at an interval between the first common plane and the first workpiece surface facing at least one of the first and second workpiece edges. At least one of the magnetic flux shields is movable in the transverse direction of the associated workpiece. The transverse flux induction coil assembly according to claim 1.

14. A transverse flux induction coil assembly for inductively heating at least a portion of an associated flat workpiece moving along a process direction relative to the transverse flux electric induction coil assembly, The associated workpiece has opposing first and second workpiece surfaces and first and second workpiece edges, The induction heating device, Comprising a first planar coil and a second planar coil disposed in a first common plane facing away from the first workpiece surface, extending between the first and second workpiece edges, and electrically coupled in series. At least one of the first planar coil and the second planar coil is adjustable to change the coil pitch. Transverse flux induction coil assembly.

15. The first planar coil is formed from a first outward leg and a first return leg that extend in a common direction and are spaced apart, and the first outward leg and the first return leg are physically and electrically coupled to a first end rail. At least one of the first outward leg and the first return leg is movably attached to the first end rail so that the first outward leg and the first return leg move toward and away from each other to change the coil pitch of the first planar coil. The second planar coil is formed from a second outward leg and a second return leg that extend in a common direction and are spaced apart, and the second outward leg and the second return leg are physically and electrically coupled to a second end rail. At least one of the second outward leg and the second return leg is movably attached to the second end rail so that the second outward leg and the second return leg move toward and away from each other to change the coil pitch of the second planar coil. The transverse flux induction coil assembly according to claim 14.

16. Further including a third planar coil and a fourth planar coil that are disposed in a second common plane facing away from the second workpiece surface at an interval, extend between the first and second workpiece edges, and are electrically coupled in series with the first planar coil and the second planar coil. The transverse flux induction coil assembly according to claim 15.

17. At least one of the third planar coil and the fourth planar coil is adjustable to change the pitch of the coil. The transverse flux induction coil assembly according to claim 16.

18. The third planar coil is formed from a third outward leg and a third return leg that extend in a common direction and are spaced apart, and the third outward leg and the third return leg are physically and electrically coupled to a third end rail. At least one of the third outward leg and the third return leg is movably attached to the third end rail so that the third outward leg and the third return leg move toward and away from each other to change the coil pitch of the third planar coil. The fourth planar coil is formed from a fourth outward leg and a fourth return leg that extend in a common direction and are spaced apart, the fourth outward leg and the fourth return leg being physically and electrically coupled to a fourth end rail, and at least one of the fourth outward leg and the fourth return leg being movably attached to the fourth end rail so that the fourth outward leg and the fourth return leg move toward and away from each other to change the coil pitch of the fourth planar coil. The transverse flux induction coil assembly according to claim 17.

19. A method of inductively heating an associated strip workpiece, supplying current to a transverse flux electric induction coil assembly to inductively heat at least a portion of the associated strip workpiece that moves along a process direction relative to the transverse flux electric induction coil assembly, the associated strip workpiece having opposing first and second workpiece surfaces and first and second workpiece edges, wherein the induction heating device comprises a first planar coil and a second planar coil that are disposed in a first common plane facing and spaced from the first workpiece surface, extend between the first and second workpiece edges, and are electrically coupled in series. The first planar coil and the second planar coil are spaced apart on the same plane, and at least one of the first planar coil and the second planar coil is movable within the common plane to change the spacing therebetween, adjusting the spacing between the first coil and the second coil. Method.

20. At least one of the first planar coil and the second planar coil is adjustable to change the pitch of the coil, and further includes adjusting the pitch of at least one coil. The method according to claim 19.

Images