Induction heating device

Abstract

To suppress damage to a power supply.SOLUTION: An induction heating device 1 comprises: a furnace 10 that accommodates a heating object 42 to be heated; a main coil 14 that is disposed outside the furnace 10 and configured to heat the heating object 42 by induction heating; and an auxiliary coil 18 that is disposed within a range influenced by a magnetic field generated by the main coil 14, belongs to a heating system independent of the main coil 14 and heats the heating object 42 by induction heating with an output lower than the output of the main coil 14. The auxiliary coil 18 is wound a plurality of turns, some of the turns being wound in a first direction, and the other turns except the turns wound in the first direction among the plurality of turns being wound in a second direction opposite to the first direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to induction heating devices. [Background technology]

[0002] For example, Patent Document 1 discloses a technique for suppressing the magnetic flux of an excitation coil by using a suppression coil different from the excitation coil. In Patent Document 1, the magnetic flux of the excitation coil generates magnetic flux in the suppression coil in the opposite direction to the magnetic flux of the excitation coil, and the magnetic flux of the excitation coil is suppressed by the magnetic flux in the opposite direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-86205 Summary of the Invention [Problem to be solved by the invention]

[0004] In some devices, a secondary coil, which is independent of the primary coil and is placed within the magnetic field of the primary coil that performs induction heating, is also used for induction heating. In such devices, an induced electromotive force is generated in the secondary coil due to the magnetic field of the primary coil, and this induced electromotive force may damage the power supply that supplies power to the secondary coil.

[0005] An object of the present disclosure is to provide an induction heating device that can suppress damage to the power supply. [Means for solving the problem]

[0006] In order to solve the above problems, an induction heating device according to one embodiment of the present disclosure comprises a furnace that accommodates an object to be heated, a main coil that is arranged outside the furnace and heats the object to be heated by induction heating, and a sub-coil that is arranged within a range that is affected by the magnetic field generated by the main coil, belongs to a heating system independent of the main coil, and heats the object to be heated by induction heating with an output that is lower than the output of the main coil, wherein the sub-coil is wound with a plurality of turns, some of the turns being wound in a first direction, and the other turns of the plurality of turns other than the turns wound in the first direction being wound in a second direction that is opposite to the first direction.

[0007] In addition, the secondary coil may be wound so that the difference between the absolute value of the induced electromotive force by the main coil in the turns wound in the first direction, summed over all the turns wound in the first direction, and the absolute value of the induced electromotive force by the main coil in the turns wound in the second direction, summed over all the turns wound in the second direction, falls within a predetermined range.

[0008] Furthermore, the secondary coil may be wound such that the turns of the multiple turns from the turn closest to the main coil to a specific turn are wound in a first direction, and the turns of the multiple turns farther from the main coil than the specific turn are wound in a second direction, such that the number of turns of the multiple turns that are relatively far from the main coil and wound in the second direction is greater than the number of turns of the multiple turns that are relatively closer to the main coil and wound in the first direction.

[0009] The secondary coil may be wound such that the inner diameter of some of the multiple turns is substantially different from the inner diameter of the other turns.

[0010] The secondary coil may also be wound so that the spacing between some adjacent turns of the plurality of turns is substantially different from the spacing between other adjacent turns.

[0011] The induction heating device may also be provided with a discharge nozzle extending vertically downward from the furnace and capable of discharging the object to be heated inside the furnace to the outside of the furnace, the main coil being arranged to surround the periphery of the furnace, and the secondary coil being arranged to surround the periphery of the discharge nozzle. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to suppress damage to the power supply. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing an example of an induction heating device according to this embodiment. [Figure 2] FIG. 2 is a partial perspective view of the induction heating device according to this embodiment, with a part cut away by a predetermined angle in the circumferential direction. [Figure 3] FIG. 3 is a partial perspective view illustrating the winding direction of the secondary coil. [Figure 4] FIG. 4 is a perspective view showing an example of a secondary coil. [Figure 5] FIG. 5 is a diagram showing an example of an induced electromotive force generated in the sub-coil by the magnetic field of the main coil. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0015] Fig. 1 is a cross-sectional view showing an example of an induction heating device 1 according to this embodiment. Fig. 2 is a partial perspective view of a part of the induction heating device 1 according to this embodiment, cut away at a predetermined angle in the circumferential direction. The induction heating device 1 includes a furnace 10, a molten metal discharge nozzle 12, a main coil 14, a first power source 16, a sub-coil 18, and a second power source 20.

[0016] The furnace 10 is a facility for containing heat. The furnace 10 has a furnace wall 30, a furnace bottom 32, a furnace cover 34, and a base 36. The furnace wall 30 is formed in a hollow cylindrical shape. The dashed-dotted line C1 in FIG. 1 indicates the central axis of the furnace wall 30, i.e., the central axis of the furnace 10. The furnace wall 30 is arranged so that its central axis extends vertically.

[0017] The hearth 32 is connected to the lower part of the furnace wall 30. The hearth 32 is tapered so as to slope vertically downward from the furnace wall 30 toward the radially inward direction. A furnace lid 34 is provided so as to be able to open and close the opening at the upper end of the furnace wall 30. A pedestal 36 is provided vertically below the hearth 32 and supports the furnace 10 via the hearth 32.

[0018] In the furnace 10, an internal space 40 is formed by the furnace wall 30, the furnace bottom 32, and the furnace lid 34. A heating object 42 to be heated is accommodated in the internal space 40 of the furnace 10. The furnace 10 is, for example, a melting furnace that heats and melts the heating object accommodated in the internal space 40.

[0019] As will be described later, the induction heating device 1 heats the object 42 to be heated using induction heating. For this reason, the object 42 to be heated is a conductive material that can be induction heated. The object 42 to be heated may be, for example, glass that becomes conductive when melted. Note that the object 42 to be heated is not limited to glass, and may be any conductive material, such as a metal.

[0020] The tapping nozzle 12 is cylindrical. The outer diameter of the tapping nozzle 12 is smaller than the outer diameter of the furnace wall 30. The tapping nozzle 12 is provided to extend vertically downward from the furnace 10. More specifically, one end of the tapping nozzle 12 is connected to the center of the lower part of the furnace bottom 32. The tapping nozzle 12 extends vertically downward from the furnace bottom 32 along the central axis of the furnace 10. The central axis of the tapping nozzle 12 substantially overlaps with the central axis of the furnace 10.

[0021] The end of the tapping nozzle 12 on the hearth 32 side is in communication with the internal space 40 of the furnace 10. The end of the tapping nozzle 12 opposite the hearth 32 is in communication with the space outside the furnace 10. The tapping nozzle 12 is capable of delivering the object to be heated housed in the internal space 40 of the furnace 10 to the outside of the furnace 10 through the tapping nozzle 12.

[0022] The main coil 14 is formed by spirally winding a conductive wire such as copper. The main coil 14 is disposed outside the furnace 10 so as to surround the periphery of the furnace 10. More specifically, the main coil 14 is wound around the outer periphery of the furnace wall 30 so that the furnace wall 30 is housed inside the main coil 14.

[0023] The main coil 14 is wound with a plurality of turns. In the example of Fig. 1, the main coil 14 is wound with six turns. Note that the number of turns of the main coil 14 is not limited to the number of turns shown in the example, and may be any number of turns that can appropriately heat the object 42 to be heated.

[0024] The main coil 14 is electrically connected to a first power supply 16. The first power supply 16 supplies AC power to the main coil 14. When AC power is supplied from the first power supply 16 to the main coil 14, a magnetic field is generated around the main coil 14 that varies over time.

[0025] When the object to be heated 42 housed in the internal space 40 of the furnace 10 is subjected to the magnetic field generated by the main coil, eddy currents are generated in the object to be heated 42 by electromagnetic induction. The object to be heated 42 is heated by Joule heat generated by the generated eddy currents. In other words, the main coil 14 can heat the object to be heated 42 by induction heating.

[0026] The secondary coil 18 is formed by spirally winding a conductive wire such as copper. The secondary coil 18 is arranged so as to surround the periphery of the discharge nozzle 12. More specifically, the secondary coil 18 is wound around the outer periphery of the discharge nozzle 12 so that the discharge nozzle 12 is housed inside the secondary coil 18.

[0027] Since the outer diameter of the tapping nozzle 12 is smaller than the outer diameter of the furnace wall 30, the inner diameter of the secondary coil 18 is smaller than the inner diameter of the main coil 14.

[0028] The secondary coil 18 is wound with a plurality of turns. In the example of Fig. 1, the secondary coil 18 is wound with 11 turns. Note that the number of turns of the secondary coil 18 is not limited to the number of turns shown in the example, and may be any number of turns that can appropriately heat the heating object 42.

[0029] The secondary coil 18 is electrically connected to a second power source 20. The second power source 20 supplies AC power to the secondary coil 18. When AC power is supplied from the second power source 20 to the secondary coil 18, a magnetic field is generated around the secondary coil 18 that varies over time.

[0030] When the object to be heated 42 inside the discharge nozzle 12 is subjected to the magnetic field generated by the secondary coil 18, eddy currents are generated in the object to be heated 42 by electromagnetic induction. The object to be heated 42 is heated by Joule heat generated by the generated eddy currents. In other words, the secondary coil 18 can heat the object to be heated 42 by induction heating.

[0031] The second power source 20 is provided separately from the first power source 16. Furthermore, the current path connecting the second power source 20 to the secondary coil 18 is independent of the current path connecting the first power source 16 to the main coil 14. Therefore, in the induction heating device 1, the secondary coil 18 can heat the object 42 inside the discharge nozzle 12 separately from the main coil 14 heating the object 42 inside the furnace 10. In other words, the secondary coil 18 belongs to a heating system independent of the main coil 14.

[0032] Furthermore, the AC power supplied by the second power supply 20 to the secondary coil 18 is set to be smaller than the AC power supplied by the first power supply 16 to the primary coil 14. In other words, the secondary coil 18 is configured to heat the object to be heated 42 by induction heating with an output lower than the output of the primary coil 14. For example, the output of the secondary coil 18 may be about 1 / 10 of the output of the primary coil 14.

[0033] In the induction heating device 1, the secondary coil 18 is positioned relatively close to the main coil 14 because the secondary coil 18 heats the object to be heated 42 inside the tapping nozzle 12. Due to this arrangement constraint, it is difficult to move the secondary coil 18 away from the main coil 14 in the induction heating device 1. In the induction heating device 1, the secondary coil 18 is positioned within a range that is affected by the magnetic field generated by the main coil 14.

[0034] Here, an induced electromotive force may be generated in the secondary coil 18 due to the magnetic field generated by the primary coil 14. If this occurs, the induced electromotive force generated in the secondary coil 18 may be applied to the second power supply 20 through the secondary coil 18, which may damage the second power supply 20.

[0035] Therefore, the secondary coil 18 of the induction heating device 1 of this embodiment is configured so that the winding direction is reversed midway through the secondary coil 18. That is, some of the multiple turns of the secondary coil 18 are wound in a first direction. Of the multiple turns of the secondary coil 18, the turns other than those wound in the first direction are wound in a second direction that is opposite to the first direction.

[0036] Fig. 3 is a partial perspective view illustrating the winding direction of the secondary coil 18. Fig. 4 is a perspective view showing an example of the secondary coil 18.

[0037] 3, the turn located vertically most upward among the multiple turns of the secondary coil 18, in other words, the turn closest to the primary coil 14, is referred to as the first turn. As the turn moves vertically downward from the first turn, in other words, as the turn moves away from the primary coil 14, the turn number increases, such as the second turn, the third turn, and so on.

[0038] 3, the winding direction of the first to third turns of the secondary coil 18 is the first direction, while the winding direction of the remaining eight turns of the secondary coil 18, the fourth to eleventh turns, is the second direction.

[0039] 4, the first direction is, for example, the counterclockwise direction when the secondary coil 18 is viewed from vertically above the secondary coil 18, as indicated by the outline arrow in Fig. 4. On the other hand, the second direction is, for example, the clockwise direction when the secondary coil 18 is viewed from vertically above the secondary coil 18.

[0040] The first direction may be the clockwise direction when the secondary coil 18 is viewed from vertically above the secondary coil 18. In this case, the second direction is the counterclockwise direction when the secondary coil 18 is viewed from vertically above the secondary coil 18.

[0041] 4, the secondary coil 18 has a reversal portion 50 where the winding direction is reversed. The secondary coil 18 may be configured such that the winding direction is reversed by, for example, bending a single coil at the reversal portion 50. Alternatively, a single secondary coil 18 with the winding direction reversed at the reversal portion 50 may be formed by joining the ends of two coils that are bent in opposite directions.

[0042] Fig. 5 is a diagram showing an example of the induced electromotive force generated in the secondary coil 18 by the magnetic field of the primary coil 14. Fig. 5 shows the real component of the induced electromotive force "Vreal", the imaginary component of the induced electromotive force "Vimag", and the "absolute value of the composite component" of the induced electromotive force, derived by simulation, for each turn of the secondary coil 18.

[0043] Hereinafter, for ease of explanation, the sum of the absolute values ​​of the induced electromotive forces of the main coil 14 in the turns wound in the first direction over all the turns wound in the first direction may be referred to as a first sum. Also, the sum of the absolute values ​​of the induced electromotive forces of the main coil 14 in the turns wound in the second direction over all the turns wound in the second direction may be referred to as a second sum.

[0044] In the example of Fig. 5, three turns from the first turn to the third turn are wound in the first direction, so the first total value is the sum of the absolute values ​​of the composite components of the three turns from the first turn to the third turn. As shown in Fig. 5, the first total value is, for example, "16.256965683".

[0045] In the example of Fig. 5, eight turns from the fourth turn to the eleventh turn are wound in the second direction, so the second total value is the sum of the absolute values ​​of the total components of the eight turns from the fourth turn to the eleventh turn. As shown in Fig. 5, the second total value is, for example, "15.74343339." In this way, the first total value and the second total value are substantially the same value.

[0046] The secondary coil 18 is wound so that the difference between the first total value and the second total value falls within a predetermined range. The predetermined range is set to a degree that allows the first total value and the second total value to be substantially the same.

[0047] Furthermore, since the winding directions in the first direction and the second direction are opposite to each other, the induced electromotive force due to the first sum value and the induced electromotive force due to the second sum value have opposite phases to each other.

[0048] In this case, the induced electromotive force in the first direction and the induced electromotive force in the second direction are substantially cancelled out.

[0049] In this way, in the induction heating device 1, some turns of the secondary coil 18 are wound in the first direction, and the other turns are wound in the second direction. This causes the induced electromotive force generated in the portion wound in the first direction and the induced electromotive force generated in the portion wound in the second direction to cancel each other out. Therefore, in the induction heating device 1, it is possible to prevent a substantial induced electromotive force from being generated in the secondary coil 18 by the main coil 14. As a result, in the induction heating device 1, it is possible to appropriately prevent damage to the second power source 20 connected to the secondary coil 18.

[0050] Furthermore, the secondary coil 18 of the induction heating device 1 is wound so that the difference between the first total value and the second total value is within a predetermined range. This makes it possible to suppress the induced electromotive force in the secondary coil 18 to a level that can be considered to be virtually non-existent. As a result, the induction heating device 1 can further suppress damage to the second power source 20 connected to the secondary coil 18.

[0051] 3 and 4, the secondary coil 18 is located relatively close to the main coil 14 and has three turns wound in the first direction. On the other hand, the secondary coil 18 is located relatively far from the main coil 14 and has eight turns wound in the second direction. In this way, the secondary coil 18 is wound so that the number of turns in the second direction, which is far from the main coil 14, is greater than the number of turns in the first direction, which is near the main coil 14.

[0052] In other words, the secondary coil 18 has multiple turns wound in a first direction, from the turn closest to the main coil 14 to a specific turn. The secondary coil 18 has multiple turns wound in a second direction that are farther from the main coil than the specific turn. The secondary coil 18 is wound so that the number of turns of the multiple turns that are relatively far from the main coil 14 and wound in the second direction is greater than the number of turns of the multiple turns that are relatively closer to the main coil 14 and wound in the first direction. In the examples of FIGS. 3 and 4, the specific turn is the third turn.

[0053] 5, the influence of the magnetic field of the main coil 14 becomes weaker for turns that are farther from the main coil 14, and the absolute value of the combined component of the induced electromotive force becomes smaller. In other words, in the sub-coil 18, the induced electromotive force in each turn that is located relatively far from the main coil 14 in either the first direction or the second direction is smaller than that in turns that are located relatively closer to the main coil 14.

[0054] Therefore, by increasing the number of turns in the secondary coil 18 in the first direction or the second direction, whichever is located relatively farther from the primary coil 14, it is possible to appropriately cancel out the induced electromotive force in the first direction portion and the induced electromotive force in the second direction portion.

[0055] The number of turns in the winding direction relatively closer to the main coil 14 is not limited to three turns, and the number of turns in the winding direction relatively farther from the main coil 14 is not limited to eight turns. The number of turns in the winding direction relatively closer to the main coil 14 and the number of turns in the winding direction relatively farther from the main coil 14 may be set appropriately taking into consideration various factors such as the total number of turns in the secondary coil 18, the distance between the main coil 14 and the secondary coil 18, and the output of the main coil 14. The ratio between the number of turns in the winding direction relatively closer to the main coil 14 and the number of turns in the winding direction relatively farther from the main coil 14 may also be set appropriately.

[0056] 3 and 4, the inner diameter of each turn of the secondary coil 18 is substantially the same for all turns. However, the secondary coil 18 may be wound so that the inner diameter of some of the multiple turns is substantially different from the inner diameter of the other turns. For example, the inner diameters of the first to tenth turns may be substantially the same, and only the eleventh turn may have a relatively smaller or larger inner diameter than the first to tenth turns.

[0057] In the induction heating device 1, by varying the inner diameter of some of the turns of the secondary coil 18, it is possible to adjust the magnetic flux of the main coil 14 passing through the inside of some of the turns. This makes it possible to adjust either or both of the first total value and the second total value in the induction heating device 1. As a result, it becomes possible in the induction heating device 1 to more appropriately cancel out the induced electromotive force in the portion in the first direction and the induced electromotive force in the portion in the second direction.

[0058] 3 and 4, the spacing between adjacent turns in the secondary coil 18 is substantially the same throughout the secondary coil 18. However, the secondary coil 18 may be wound so that the spacing between some adjacent turns of the multiple turns is substantially different from the spacing between other adjacent turns. For example, the spacing between adjacent turns from the first turn to the tenth turn may be substantially the same, and the spacing between the tenth and eleventh turns may be relatively narrower or wider than these spacings.

[0059] In the induction heating device 1, by varying the spacing between some adjacent turns in the sub-coil 18, it is possible to adjust the distance of some turns from the main coil 14. This makes it possible to adjust either or both of the first total value and the second total value in the induction heating device 1. As a result, it becomes possible in the induction heating device 1 to more appropriately cancel out the induced electromotive force in the portion in the first direction and the induced electromotive force in the portion in the second direction.

[0060] As described above, in the induction heating device 1, the main coil 14 is arranged to surround the furnace 10, and the secondary coil 18 is arranged to surround the tapping nozzle 12. This suppresses the induced electromotive force in the secondary coil 18, thereby preventing damage to the second power source 20 that supplies power to the secondary coil 18. As a result, in the induction heating device 1, the second power source 20 can supply appropriate power to the secondary coil 18, allowing the secondary coil 18 to appropriately heat the object to be heated 42 inside the tapping nozzle 12. This makes it possible to prevent the object to be heated 42 from clogging the inside of the tapping nozzle 12, for example.

[0061] The induction heating device 1 is not limited to the example in which the main coil 14 is disposed in the furnace 10 and the secondary coil 18 is disposed in the discharge nozzle 12. The induction heating device 1 may be applied to any device in which induction heating is performed in each of the main coil 14 and the secondary coil 18 that is disposed within the range of influence of the magnetic field of the main coil 14.

[0062] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0063] This disclosure can contribute, for example, to Sustainable Development Goals (SDGs) Goal 7: "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13: "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0064] 1 Induction heating device 10 furnace 12 Water outlet nozzle 14 Main coil 18 Secondary coil 42 Heating object

Claims

1. a furnace that accommodates an object to be heated; a main coil disposed outside the furnace and configured to heat the object to be heated by induction heating; a sub-coil that is disposed within a range affected by the magnetic field generated by the main coil, belongs to a heating system independent of the main coil, and heats the object to be heated by induction heating with an output lower than that of the main coil; Equipped with The secondary coil is It is wound with multiple turns, Some of the turns are wound in a first direction, An induction heating device, wherein the turns other than the turns wound in the first direction among the plurality of turns are wound in a second direction opposite to the first direction.

2. 2. The induction heating device according to claim 1, wherein the secondary coil is wound so that a difference between the absolute value of the induced electromotive force of the primary coil in the turns wound in the first direction, calculated by summing all the turns wound in the first direction, and the absolute value of the induced electromotive force of the primary coil in the turns wound in the second direction, calculated by summing all the turns wound in the second direction, falls within a predetermined range.

3. The secondary coil is The plurality of turns are wound in the first direction from the turn closest to the main coil to a specific turn, a turn of the plurality of turns that is farther from the main coil than the specific turn is wound in the second direction; 2. The induction heating device according to claim 1, wherein the number of turns of the plurality of turns that are relatively far from the main coil and wound in the second direction is greater than the number of turns of the plurality of turns that are relatively close to the main coil and wound in the first direction.

4. The secondary coil is 2. The induction heating device according to claim 1, wherein the coil is wound such that the inner diameter of some of the plurality of turns is substantially different from the inner diameter of the other turns.

5. The secondary coil is 2. The induction heating device according to claim 1, wherein the plurality of turns are wound such that the spacing between some adjacent turns is substantially different from the spacing between other adjacent turns.

6. a melting point nozzle extending vertically downward from the furnace and capable of delivering the object to be heated inside the furnace to the outside of the furnace; the main coil is disposed so as to surround the periphery of the furnace; The induction heating device according to claim 1 , wherein the secondary coil is disposed so as to surround the periphery of the discharge nozzle.

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