JP2009097734A - Induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating device capable of shortening the time necessary for melting a substance charged into a crucible by efficiently heating a bottom portion of the crucible. <P>SOLUTION: In this induction heating device comprising a bottomed cylindrical crucible 10 having a uniform thickness and provided with an opening 11 at its upper end, and an induction heating coil 20 disposed at an outer peripheral area of the crucible 10 in a state of being wound on the crucible 10, and melting the substance charged inside from the opening 11 by induction-heating the crucible 10 by distributing electricity to the induction heating coil 20, a side portion 12 of the crucible 10 includes a cylindrical upper end portion 12a forming the opening 11, and a basic end portion 12b formed continuously from the upper end portion 12a and a bottom portion 13 of the crucible 10, and formed into the shape having an outer diameter gradually reduced toward the bottom portion 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an induction heating device, and more specifically, the induction heating coil disposed in a manner of winding a metal crucible is energized to heat the crucible, and is introduced into the crucible. The present invention relates to an improvement of an induction heating apparatus for melting a formed material.

  Conventionally, the following devices are known as induction heating devices for melting a material charged in a crucible by induction heating. That is, the induction heating coil is disposed in the outer peripheral region of the bottomed cylindrical metal crucible in such a manner that the outer portion of the crucible is wound. Here, the crucible will be described in detail. The crucible has a bottomed cylindrical shape having a side portion that forms a cylindrical shape and a disk-shaped bottom portion that is provided so as to close an opening on the lower end side of the side portion. And having an opening at the upper end, the wall thickness is uniform.

  In such an induction heating device, an alternating current is passed through an induction heating coil to make it energized, and an alternating magnetic flux is applied to generate an eddy current in the crucible to induce induction heating of the crucible. The substance (melting material) thrown into the inside of the container is melted (see, for example, Patent Document 1).

Japanese National Patent Publication No. 10-500616

  By the way, in the induction heating apparatus described above, the eddy current generated when the induction heating coil is energized is induced in a portion close to the induction heating coil, that is, on the outer side surface of the crucible. It is generally strong and weakens toward the inside. This makes it difficult to generate a strong eddy current at the bottom of the crucible even when an alternating current is passed through the induction heating coil, and heating of the bottom depends on heat conduction from the side. It will be. Since the crucible has a bottomed cylindrical shape, it is difficult for a magnetic field to reach the bottom, and the bottom has a sufficiently large area. This requires a considerable amount of time to heat the bottom. On the other hand, in order to shorten the time required for heating the bottom, it is conceivable to increase the alternating current flowing through the induction heating coil, but this causes the side of the crucible to be heated more than necessary, and the bottom is heated. There was a risk that the side would be damaged before it was done. Therefore, in the conventional induction heating apparatus, the material to be melted cannot be melted satisfactorily until the bottom is sufficiently heated, and there is a possibility that the time required for melting the substance may be lengthened.

  In view of the above circumstances, the present invention provides an induction heating apparatus that can efficiently heat the bottom of a crucible and reduce the time required to melt the material charged into the crucible. Objective.

  In order to achieve the above object, an induction heating apparatus according to claim 1 of the present invention includes a bottomed cylindrical crucible having a uniform wall thickness and having an opening at an upper end, and the crucible in an outer peripheral region of the crucible. An induction heating coil arranged in a winding manner, and by induction heating the crucible with the induction heating coil in an energized state, in an induction heating apparatus that melts the substance introduced into the inside through the opening A side portion of the crucible is formed continuously with a cylindrical upper end portion that forms the opening, and the upper end portion and the bottom portion of the crucible, and has a shape in which an outer diameter gradually decreases toward the bottom portion. And an end portion.

  In addition, the induction heating device according to claim 2 of the present invention is characterized in that, in the above-described claim 1, the base end portion is tapered in such a manner that the diameter gradually decreases toward the bottom portion.

  An induction heating device according to claim 3 of the present invention is the induction heating coil according to claim 1 or 2, wherein the induction heating coil has a sparse area facing a boundary portion between the upper end and the base end. It is characterized in that it is wound and arranged in such a manner.

  According to a fourth aspect of the present invention, there is provided the induction heating apparatus according to any one of the first to third aspects, wherein the induction heating coil is connected to one power source.

  According to the induction heating apparatus of the present invention, the base end portion of the side portion of the crucible is shaped in such a manner that the outer diameter gradually decreases toward the bottom portion, so that the area of the bottom portion of the crucible is sufficiently small. In addition, a magnetic field can be applied to the bottom. Further, as a result of the base end portion also facing the induction heating coil, an eddy current is generated and heated. Thereby, the bottom can be heated by the action of the magnetic field and the heat conduction from the side, and since the area of the bottom is sufficiently small, the time required for heating the bottom can be shortened. Therefore, the bottom part of the crucible can be efficiently heated, and the time required for melting the material put into the crucible can be shortened.

  Exemplary embodiments of an induction heating apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiments, an induction heating apparatus in which a target molten substance (material to be melted) is an asbestos-containing heat insulating material (insulator) will be described.

  FIG. 1 schematically shows an induction heating apparatus according to an embodiment of the present invention, and a part thereof is shown in cross section. The induction heating apparatus exemplified here includes an induction furnace 1.

  The induction furnace 1 has a bottomed cylindrical shape, and a crucible 10, a yoke 14, and an induction heating coil 20 are disposed therein. A part of the side peripheral surface of the induction furnace 1 is provided with a protruding part 2 that protrudes outward, and the protruding part 2 is provided with a through hole 3. A rod-shaped shaft portion 4 passes through the through-hole 3, so that the induction furnace 1 can swing around the shaft center of the shaft portion 4.

  The crucible 10 is made of a metal such as stainless steel or Inconel material (trade name), and has a bottomed cylindrical shape having an opening 11 at the upper end. The crucible 10 is disposed in the central region of the induction furnace 1, the inner surface of the side portion 12 constitutes a part of the inner peripheral surface of the induction furnace 1, and the bottom portion 13 constitutes the inner bottom portion of the induction furnace 1. is doing. The outer peripheral surface of the crucible 10, that is, the outer surface of the side portion 12 is covered with a heat insulating material 15. In the crucible 10, the thickness of the bottom portion 13 is equal to the thickness of the side portion 12. That is, the crucible 10 has a uniform thickness.

  The side portion 12 of the crucible 10 includes an upper end portion 12a and a proximal end portion 12b. The upper end portion 12 a is a cylindrical portion that forms the opening 11. The base end portion 12 b is a portion that is formed continuously with the upper end portion 12 a and the bottom portion 13, and is tapered in such a manner that the outer diameter gradually decreases toward the bottom portion 13. That is, the outer surface of the base end portion 12b is an inclined surface.

  The yoke 14 is disposed in the outer peripheral area of the crucible 10 at a position separated from the outer peripheral surface of the crucible 10 by a predetermined distance. More specifically, the yoke 14 has a substantially cylindrical shape, and is fixedly disposed on the induction furnace 1 while being placed on the upper surface of the annular refractory brick 16. The yoke 14 prevents leakage of magnetic flux, which will be described later, and supports the induction heating coil 20.

  The induction heating coil 20 is formed in a cylindrical shape between the crucible 10 and the yoke 14 in a manner in which the crucible 10 is wound at a position separated from the outer peripheral surface of the crucible 10 by a predetermined distance. Supported by iron 14. The length of the induction heating coil 20 in the vertical direction is sufficiently larger than the length of the crucible 10 in the vertical direction. Such an induction heating coil 20 is connected to one power source 21 to constitute an electric circuit. The power source 21 supplies an alternating current of several tens Hz to several kHz.

  Such an induction heating coil 20 is wound in such a manner that a region facing the boundary portion between the upper end portion 12a and the base end portion 12b via the heat insulating material 15 is sparse. More specifically, it is wound so that a gap 22 is formed in a region facing the boundary portion between the upper end portion 12a and the base end portion 12b via a heat insulating structure. Further, in the upper region of the gap 22, that is, the portion of the coil facing the upper end portion 12a, and the lower portion of the gap 22, that is, the portion of the coil corresponding to the lower region of the base end portion 12b and the crucible 10, The width of the direction is different, and the coil in the lower region is smaller than the gap 22 in the height direction. Therefore, the coil in the lower region of the gap 22 is wound more densely than the coil in the upper region of the gap 22.

  In such an induction heating coil 20, the distance H (up and down direction) H of the gap 22 and the separation distance δ from the outer peripheral surface of the crucible 10 are such that the mutual product H · δ is a predetermined value. It is. That is, when the distance H of the gap 22 is increased, the separation distance δ from the outer peripheral surface of the crucible 10 is decreased, whereas when the distance H of the gap 22 is decreased, the separation distance from the outer peripheral surface of the crucible 10 is decreased. δ increases.

  Reference numeral 17 in FIG. 1 is an area indicating the periphery and the lower area of the crucible 10, and this area is filled with a granular refractory material. Reference numeral 18 denotes a guide portion. The guide part 18 is a part that serves as a guide when the material (melt) melted in the crucible 10 is taken out. This guide part 18 is comprised with the clay-like refractory. Further, reference numeral 19 denotes a circuit switch formed by the induction heating coil 20.

  The induction heating apparatus having the above-described configuration melts the asbestos-containing heat insulating material that has been put into the interior as follows. 2 to 6 schematically show the melting procedure of the asbestos-containing heat insulating material, respectively.

  First, as shown in FIG. 2, a melting point depressant a such as an alkaline flux is introduced through the opening 11 of the crucible 10. Thereafter, as shown in FIG. 3, the switch 19 is turned on, an alternating current is passed through the induction heating coil 20 to be in an energized state, and an alternating magnetic flux is applied. Thereby, an eddy current is generated in the crucible 10, and the crucible 10 is heated by Joule heat due to eddy current loss, that is, induction heating. As a result, the crucible 10 is sufficiently heated to the required temperature, so that the melting point depressant a introduced into the inside through the opening 11 is melted by the heat from the crucible 10.

  Then, as shown in FIG. 4, the asbestos-containing heat insulating material b is introduced through the opening 11 of the crucible 10, and the opening 11 of the crucible 10 is closed with a furnace lid (not shown). The asbestos-containing heat insulating material b is melted by heat. Thereafter, the switch 19 is turned off, the furnace lid is moved to open the opening 11 of the crucible 10, and the induction furnace 1 is swung around the axis of the shaft portion 4 as shown in FIG. A certain melt is discharged. Thereafter, the switch 19 is turned on again, and the above-described procedure is repeated as necessary. By performing such a procedure, the asbestos-containing heat insulating material b can be reliably melted and rendered harmless.

  In the induction heating apparatus, since the base end portion 12b of the side portion 12 of the crucible 10 is tapered in such a manner that the outer diameter gradually decreases toward the bottom portion 13, the area of the bottom portion 13 of the crucible 10 is reduced. It can be small enough.

  Moreover, although the base end part 12b of the crucible 10 does not oppose the induction heating coil 20 via a heat insulation structure like the upper end part 12a, since it faces the induction heating coil 20 via a heat insulation structure, When an alternating magnetic flux is applied, the magnetic field reaches and an eddy current is generated and heated. Moreover, since the base end portion 12b is tapered, the magnetic field reaches the bottom portion 13 to some extent.

  7 to 12 schematically show magnetic field analysis results and generated power distribution, respectively. More specifically, FIG. 7 shows magnetic field analysis results of the crucible and the induction heating coil constituting the induction heating apparatus of the present invention, the shape of the crucible is the same as that of the above embodiment, and the induction heating coil Is wound without a gap. FIG. 8 shows the magnetic field analysis results of the crucible and the induction heating coil constituting the induction heating apparatus in the embodiment of the present invention, the shape of the crucible is the same as that of the above embodiment, It is wound with a gap. 9 and 10 show the power distributions shown in FIGS. 7 and 8, respectively. FIGS. 11 and 12 both relate to a conventional induction heating apparatus. FIG. 11 shows that the shape of the crucible is a bottomed cylindrical shape, and the induction heating coil is wound without providing a gap. . FIG. 12 shows the power distribution in the case shown in FIG.

  As shown in FIGS. 7 and 9, since the base end portion 12 b of the side portion 12 of the crucible 10 is tapered in such a manner that the outer diameter gradually decreases toward the bottom portion 13, the bottom portion 13 of the crucible 10. It is clear that the magnetic field reaches (a) in the figure to some extent, and that the bottom 13 can be heated.

  As shown in FIG. 8 and FIG. 10, the induction heating coil 20 is wound by providing a gap 22 in a region facing the boundary portion between the upper end portion 12 a and the base end portion 12 b of the crucible 10 through a heat insulating structure. It is clear that the magnetic field concentration at the boundary can be suppressed.

  On the other hand, as shown in FIGS. 11 and 12, it is clear that the magnetic field concentrates on the upper end of the side portion 12 of the crucible 10 and hardly reaches the bottom portion 13.

  As described above, according to the induction heating device in the embodiment of the present invention, the base end portion 12b of the side portion 12 of the crucible 10 is tapered so that the outer diameter gradually decreases toward the bottom portion 13. Therefore, the area of the bottom 13 of the crucible 10 can be made sufficiently small, and a magnetic field can be applied to the bottom 13 as well. Further, the base end portion 12b is also heated by generating an eddy current. Thereby, the heating of the bottom 13 can be performed by the action of a magnetic field and the heat conduction from the side 12, and since the area of the bottom 13 is sufficiently small, the time required for heating the bottom 13 is shortened. be able to. Therefore, it is possible to efficiently heat the bottom 13 of the crucible 10 and to shorten the time required for melting the material put into the crucible 10.

  According to the induction heating apparatus, the induction heating coil 20 is wound in such a manner that a region facing the boundary portion between the upper end portion 12a and the base end portion 12b of the crucible 10 is sparse, that is, a gap is formed in the region facing the boundary portion. Since the winding 22 is provided, it is possible to prevent the magnetic field from being concentrated on the boundary portion, thereby preventing the occurrence of local heating in which the boundary portion is heated more than necessary. Therefore, the bottom 13 of the crucible 10 can be efficiently heated by this, and the side 12 can be heated substantially uniformly.

  Further, according to the induction heating device, since the induction heating coil 20 is connected to the single power source 21 to constitute an electric circuit, not only the operation cost is reduced, but also the cost required for the entire device is required. There is no fear of becoming higher.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made. For example, in the above-described embodiment, the induction heating coil 20 is disposed in such a manner that the gap 22 is provided and wound. However, in the present invention, the gap 22 is not necessarily required.

  Further, in the above-described embodiment, the base end portion 12b of the side portion 12 of the crucible 10 has a tapered shape. However, in the present invention, if the outer diameter gradually decreases toward the bottom portion 13, The shape is not particularly limited, and the outer surface of the base end may be spherical.

  Further, in the above-described embodiment, the induction heating coil 20 is arranged in a cylindrical shape in a manner in which the crucible 10 is wound at a position separated from the outer peripheral surface of the crucible 10 by a predetermined distance. However, in the present invention, the induction heating coil does not need to have a cylindrical shape, and may be arranged in such a manner that the crucible is wound in a state where the distance from the crucible is kept constant. That is, the portion corresponding to the base end portion of the crucible may be wound in such a manner that the outer diameter gradually decreases as it goes downward.

  As described above, the induction heating apparatus according to the present invention is charged into the inside of the crucible by induction heating the crucible while the induction heating coil disposed in a manner of winding a metal crucible is energized. It is useful for melting the formed material.

It is the schematic diagram which showed typically the induction heating apparatus in embodiment of this invention, and has shown one part in the cross section. It is a schematic diagram which shows typically the fusion | melting procedure of an asbestos containing heat insulating material. It is a schematic diagram which shows typically the fusion | melting procedure of an asbestos containing heat insulating material. It is a schematic diagram which shows typically the fusion | melting procedure of an asbestos containing heat insulating material. It is a schematic diagram which shows typically the fusion | melting procedure of an asbestos containing heat insulating material. It is a schematic diagram which shows typically the fusion | melting procedure of an asbestos containing heat insulating material. The magnetic field analysis result of the crucible and induction heating coil which comprise the induction heating apparatus of this invention is shown. The magnetic field analysis result of the crucible and induction heating coil which comprise the induction heating apparatus in embodiment of this invention is shown. The power distribution in the case shown in FIG. 7 is shown. The power distribution in the case shown in FIG. 8 is shown. The magnetic field analysis result of the crucible and induction heating coil which comprise the conventional induction heating apparatus is shown. The power distribution in the case shown in FIG. 11 is shown.

Explanation of symbols

10 crucible 12 side portion 12a upper end portion 12b base end portion 13 bottom portion 14 yoke 20 induction heating coil 21 power source 22 gap

Claims (4)

A bottomed cylindrical crucible having a uniform wall thickness and an opening at the upper end;
An induction heating coil disposed in a manner in which the crucible is wound around the outer periphery of the crucible, and the induction heating coil is energized to inductively heat the crucible. In an induction heating device that melts a substance,
The side of the crucible is
A cylindrical upper end forming the opening;
An induction heating apparatus comprising: a base end portion formed continuously from the upper end portion and the bottom portion of the crucible and having a shape in which an outer diameter gradually decreases toward the bottom portion.   The induction heating apparatus according to claim 1, wherein the base end portion is tapered in a mode in which a diameter gradually decreases toward a bottom portion.   3. The induction according to claim 1, wherein the induction heating coil is disposed by being wound in such a manner that a region facing a boundary portion between the upper end portion and the base end portion is sparse. Heating device.   The induction heating apparatus according to claim 1, wherein the induction heating coil is connected to a single power source.

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