Melting device

Abstract

The invention relates to a melting device. This melting device is provided with: a heating coil unit into which a first melting material is inserted; a support part that supports the lower end of the first molten material from below at a position above the lower end of the heating coil part; and a guide part that guides the second molten raw material such that the second molten raw material is inserted into the heating coil part in a stacked state so as to be in contact with the first molten raw material.

Description

[0001] This application is a divisional application of the invention patent application with application number 201910585663.7, application date July 1, 2019, and invention name “Melting Device”. Technical Field

[0002] The present invention relates to a melting device, and more particularly to a melting device having a heating coil portion into which a melting raw material is inserted. Background Art

[0003] Conventionally, there is known a melting device including a heating coil portion into which a melting raw material is inserted. Japanese Patent No. 2819711 discloses such a melting device.

[0004] The above-mentioned Japanese Patent Gazette No. 2819711 discloses a melting device having a melting furnace, into which an aluminum ingot (ingot) is inserted and melted. Specifically, the melting furnace includes a cylindrical furnace body made of refractory material and a cold material introduction guide arranged on the upper side of the furnace body. An induction coil is provided on the outer peripheral side of the furnace body, and the induction coil is used to heat the aluminum ingot inserted into the furnace body to melt it. In addition, the cold material introduction guide is provided to guide the aluminum ingot into the interior of the melting furnace (furnace body). In addition, an outflow port for allowing the melted aluminum to flow out is provided at the bottom of the cylindrical melting furnace.

[0005] In addition, in the above-mentioned melting device, when the ingot inside the furnace body is melted and the upper end of the ingot reaches the central position in the direction of the central axis of the induction coil provided in the melting furnace, the aluminum ingot to be melted after the currently melted ingot (hereinafter referred to as the next melted ingot) is inserted into the furnace body by means of the cold material introduction guide. That is, after the currently melted ingot is melted and reduced to a predetermined size, the next melted ingot is inserted. As a result, the next melted aluminum ingot is immediately inserted to the position with the highest melting efficiency (the central position in the direction of the central axis of the induction coil) after being inserted into the furnace body by means of the cold material introduction guide, and is therefore not arranged (retained) in a cold state in the cold material introduction guide. As a result, even if the flow outlet is blocked and the melted ingot does not flow out from the flow outlet, and the melted ingot is scattered in the furnace body, since the next melted ingot is not cold (heated), even if the scattered ingot adheres to the next melted ingot, the adhered ingot is melted immediately.

[0006] However, in the melting device described in the above-mentioned Japanese Patent No. 2819711, since the next ingot to be melted is put in after the ingot currently being melted is melted and reduced to a predetermined size, there is a problem that the load of induction heating by the induction coil (the size of the ingot to be heated) changes rapidly at the moment the next ingot to be melted is put in. Therefore, there is a problem that the control of induction heating by the induction coil becomes unstable, and it is difficult to melt the ingot continuously and stably. Summary of the invention

[0007] The present invention is made to solve the above-mentioned problems, and one of the objects of the present invention is to provide a melting device capable of stably and continuously melting a melting raw material currently being melted and a melting raw material to be melted subsequent to the currently melting raw material.

[0008] In order to achieve the above-mentioned purpose, a melting device according to one aspect of the present invention comprises: a heating coil portion, into which a first melting raw material is inserted; a supporting portion, which includes a through hole, through which the melted first melting raw material flows and then falls, and the supporting portion supports the lower end of the first melting raw material from below at a position above the lower end of the heating coil portion; and a guiding portion, which guides a second melting raw material that is melted after the first melting raw material is melted, so that the second melting raw material is inserted into the heating coil portion in a state of being stacked in contact with the first melting raw material.

[0009] In the melting device according to one aspect of the present invention, as described above, the support portion supports the lower end of the first molten raw material from below at a position above the lower end of the heating coil portion. As a result, the lower end of the first molten raw material is arranged at a position above the lower end of the heating coil portion, so that the magnetic flux from the heating coil portion fully reaches the lower end of the first molten raw material and the portion near the lower end. As a result, the lower end of the first molten raw material and the portion near the lower end can be quickly melted, so that the through hole can be prevented from being blocked by the melt residue of the lower end of the first molten raw material. As a result, the first molten raw material can be smoothly flowed out of the through hole, and the first molten raw material can be prevented from scattering. As a result, the scattered first molten raw material can be prevented from adhering to the second molten raw material. Here, when the second molten raw material is inserted into the heating coil portion in a state where the second molten raw material is stacked in contact with the first molten raw material, the magnetic flux from the heating coil portion sometimes does not reach the second molten raw material, and the second molten raw material is in a cold state. However, even in this case, since the scattering of the first molten raw material is suppressed, the scattered first molten raw material is suppressed from adhering to the second molten raw material, and thus the movement of the second molten raw material can be suppressed from being hindered by the scattered first molten raw material. Thus, it is not necessary to control the timing in such a way that the second molten raw material is inserted after the first molten raw material is melted and reduced to a predetermined size in order to make the second molten raw material in a heated state at the time of insertion. That is, even in the case where the second molten raw material is stacked with the first molten raw material and inserted into the heating coil part using a guide before the first molten raw material is melted and reduced to a predetermined size, the second molten raw material can be smoothly inserted into the heating coil part. As a result, the size of the heating object heated by the heating coil part can be fixed. Thus, the load borne by the heating coil part can be fixed. As a result, the first molten raw material and the second molten raw material can be stably and continuously melted.

[0010] In the melting device based on one aspect described above, it is preferred that the melting device further comprises a melting furnace, the heating coil portion is wound around the melting furnace, the first melting raw material is inserted into the melting furnace, the guide portion is mounted on the melting furnace, and the melting furnace and the support portion are independently provided. If configured in this way, the melting furnace and the support portion can be replaced independently of each other, so that the replacement operation of the melting furnace and the support portion can be facilitated. In addition, by replacing the support portion, the size (height) of the support portion can be changed, so that the melting characteristics (melting speed, etc.) of the first melting raw material can be easily adjusted.

[0011] In this case, it is preferable that the support portion is provided so as to be surrounded by the inner peripheral surface of the melting furnace. With such a configuration, the movement of the support portion is restricted by the inner peripheral surface of the melting furnace, and thus the positional deviation of the support portion can be suppressed.

[0012] In the melting device according to the above aspect, it is preferred that the support part and the guide part are respectively made of non-magnetic materials. If so, it is possible to suppress the magnetic flux from the heating coil part from being affected by the support part and the guide part, so that the first melting material can be stably melted by the heating coil part.

[0013] In the melting device according to one aspect above, it is preferred that a high-frequency power supply for supplying power to the heating coil unit is further provided, and the melting device is configured such that, when the power supplied from the high-frequency power supply to the heating coil unit is set to be fixed, the melting time for melting the first melting raw material by the heating coil unit is determined based on the relationship between the pre-set melting amount of the first melting raw material and the supply amount of power from the high-frequency power supply. If configured in this way, the required amount of the first melting raw material can be melted without detecting the melting amount by a weight sensor or the like. As a result, the number of components for melting the first melting raw material can be reduced. In addition, compared with the case where the power of the high-frequency power supply is controlled based on the melting amount (feedback control), the control for melting the first melting raw material can be simplified.

[0014] In addition, since the amount of power supplied from the high frequency power source is fixed, the load of control for determining the melting time of the first melting raw material can be reduced compared to a case where the amount of power supplied varies. In addition, compared to a case where the user manually calculates (determines) the melting time, the melting time can be calculated accurately and quickly.

[0015] In the melting device according to the above aspect, it is preferred that the support portion includes a raw material support surface portion, which supports the lower end of the first molten raw material at a position above the lower end of the heating coil portion, and the raw material support surface portion is configured to support the central portion of the lower end of the first molten raw material when viewed from above. Here, when the first molten raw material is heated by the magnetic flux of the heating coil portion, the surface of the first molten raw material is mainly heated due to the skin effect. As a result, the first molten raw material starts to melt from the outer surface, and the central portion of the molten raw material melts at a relatively late stage. In other words, the melting progresses gradually from the outer surface of the first molten raw material to the center. In addition, the magnetic flux is concentrated on the lower end (corner) of the first molten raw material, so the melting progresses faster on the lower end side. As a result, the first molten raw material has a shape in which the front end becomes thinner as it goes downward. Therefore, by configuring the raw material support surface portion to support the central portion of the lower end of the first molten raw material, the front end (lower end) side of the first molten raw material with a thinned front end can be supported in a stable state.

[0016] In this case, it is preferred that a plurality of through holes are provided, and the raw material support surface portion is constituted by a portion of the support portion located between the plurality of through holes. If so constituted, the plurality of through holes are provided adjacent to the raw material support surface portion. Furthermore, the first molten raw material melted from the first molten raw material flows toward the front end side (the portion in contact with the raw material support surface portion) of the first molten raw material having a tapered shape, so that the melted first molten raw material can fall more smoothly from the plurality of through holes adjacent to the raw material support surface portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram showing the overall structure of the melting device according to the first embodiment.

[0018] Figure 2 This is a perspective view of a support portion of a melting device according to the first embodiment and the second embodiment.

[0019] Figure 3 This is a plan view of a support portion of a melting device according to the first embodiment and the second embodiment.

[0020] Figure 4 This is a side view of a support portion of a melting device according to the first embodiment and the second embodiment.

[0021] Figure 5 This is a diagram showing the distribution of magnetic flux density near the heating coil portion obtained by simulation (a state in which the lower end of the heating coil portion and the lower end of the molten raw material are substantially flush with each other).

[0022] Figure 6 This is a diagram showing the distribution of magnetic flux density near the heating coil unit obtained by simulation (a state in which the lower end of the molten raw material is arranged above the lower end of the heating coil unit).

[0023] Figure 7 This is a diagram showing the distribution of Joule heat density near the heating coil unit obtained by simulation (based on the first embodiment and the second embodiment).

[0024] Fig. 8A This is a diagram for explaining a state in which a molten raw material is melted (based on the first embodiment and the second embodiment).

[0025] Figure 8B This is a diagram for explaining a state in which the melting of the molten raw material progresses (based on the first embodiment and the second embodiment).

[0026] Fig. 9 This is a diagram for explaining the relationship between time and electric power when a plurality of molten raw materials are melted continuously.

[0027] Fig.10This is a schematic diagram showing the overall structure of a melting device according to the second embodiment.

[0028] Fig.11 This is a schematic diagram showing the overall structure of a melting device according to a first modification example of the first embodiment and the second embodiment.

[0029] Fig.12 This is a perspective view of a support portion of a melting device according to a first modification example of the first embodiment and the second embodiment.

[0030] Fig.13 This is a perspective view of a support portion of a melting device according to a second modification of the first embodiment and the second embodiment. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0032] [First embodiment]

[0033] Reference Figures 1 to 9 The structure of the melting device 100 according to the first embodiment will be described.

[0034] (Structure of melting device)

[0035] like Figure 1 As shown, the melting device 100 includes a high-frequency power supply board 1. The high-frequency power supply board 1 is configured to supply high-frequency (for example, 10 kHz) AC power to the heating coil unit 11 described later. In addition, the high-frequency power supply board 1 is an example of the "high-frequency power supply" of the present invention. In addition, Figure 1 This is a schematic diagram, and illustration of components that are not necessary for the description is omitted.

[0036] The high frequency power board 1 is supplied with AC power from the AC power supply 101. The high frequency power board 1 includes a rectifier 1a that converts the AC power from the AC power supply 101 into DC power. The high frequency power board 1 includes a smoothing unit 1b that smoothes the DC power converted by the rectifier 1a. The high frequency power board 1 includes an inverter 1c that converts the DC power smoothed by the smoothing unit 1b into AC power.

[0037] The melting device 100 is provided with a heating unit 10 provided with a heating coil unit 11 described later. The heating unit 10 is provided adjacent to the high-frequency power supply plate 1 .

[0038] In the heating part 10 of the melting device 100, a heating coil part 11 is provided for inserting the molten raw material 200. In addition, the molten raw material 200 is formed of a non-magnetic material. For example, the molten raw material 200 is formed of aluminum, zinc, copper, etc. In addition, the molten raw material 200 is configured as an ingot (a thing formed into a piece of refined metal). In addition, the molten raw material 200 has a roughly prismatic shape (a roughly rectangular parallelepiped shape). In addition, when viewed from the extension direction (Z direction) of the molten raw material 200, the molten raw material 200 has a roughly rectangular shape. In addition, the molten raw material 200 is an example of the "first molten raw material" of the present invention.

[0039] The heating coil unit 11 is an induction heating type heating coil unit 11. That is, the heating coil unit 11 generates a magnetic flux (magnetic field) by using the AC power supplied from the high-frequency power supply board 1. Then, by this magnetic flux, a high-density eddy current (skin effect) is generated near the surface of the molten raw material 200 inserted into the heating coil unit 11. Then, by the Joule heat of this eddy current, the surface of the molten raw material 200 is heated.

[0040] In addition, the melting device 100 includes a melting furnace 11a provided in the heating unit 10. The heating coil unit 11 is wound around the melting furnace 11a, and the melted raw material 200 is inserted into the melting furnace 11a.

[0041] The melted raw material 200 that has flowed through the through hole 22 described later and dropped is held in the holding furnace 102. By turning on the high-frequency power supply plate 1, the melting of the melted raw material 200 starts, and the melted raw material 200 is stored in the holding furnace 102. Then, the high-frequency power supply plate 1 is turned off at the moment when the desired amount of the melted raw material 200 is obtained, thereby stopping the melting of the melted raw material 200.

[0042] The melting device 100 includes a support portion 20, which is disposed on the lower side of the heating coil portion 11 and supports the lower end 200a of the molten raw material 200 from below. The support portion 20 supports the lower end 200a of the molten raw material 200 from below at a position above the lower end 11b of the heating coil portion 11. Specifically, the support portion 20 includes a raw material support surface portion 21, which supports the lower end 200a of the molten raw material 200 at a position above (Z1 direction side) the lower end 11b of the heating coil portion 11.

[0043] Specifically, the material support surface portion 21 is disposed above the lower end 11b of the heating coil portion 11 by a length L12 that is 18% or more of the length L11 of the heating coil portion 11 in the vertical direction. More preferably, the material support surface portion 21 is disposed above the lower end 11b of the heating coil portion 11 by a length L12 that is 25% or more of the length L11 of the heating coil portion 11. Thus, the lower end 200a of the molten material 200 is positioned by the material support surface portion 21, and the lower end 200a of the molten material 200 is disposed above the lower end 11b of the heating coil portion 11 by a distance L12.

[0044] Here, in the first embodiment, the melting furnace 11a and the support part 20 are provided independently of each other. Specifically, the support part 20 is inserted into the inside of the melting furnace 11a. That is, the support part 20 is provided so as to be surrounded by the inner peripheral surface 11c of the melting furnace 11a. In detail, the entire support part 20 is surrounded by the inner peripheral surface 11c near the lower end 11d of the melting furnace 11a.

[0045] The melting device 100 includes a guide portion 30. The guide portion 30 is mounted on the melting furnace 11a. The guide portion 30 guides the melted raw material 201 melted after the melted raw material 200 is melted so that the melted raw material 201 is inserted into the heating coil portion 11 (melting furnace 11a) in a state where it is stacked in contact with the melted raw material 200. Specifically, the guide portion 30 has a cylindrical shape. The movement (inclination) of the melted raw material 201 inserted into the guide portion 30 is restricted by the inner peripheral surface 31 of the guide portion 30 so as to prevent the melted raw material 201 from inclination. Then, as the melting of the melted raw material 200 progresses, the melted raw material 201 held vertically by the guide portion 30 is guided by the guide portion 30 in a state held vertically so as to be inserted into the inside of the melting furnace 11a. In addition, the melted raw material 201 is inserted into the inside of the melting furnace 11a through the guide portion 30 while being placed on the upper end surface 200b of the melted raw material 200. The molten raw material 201 is an example of the "second molten raw material" of the present invention.

[0046] In addition, the timing of placing the molten raw material 201 on the upper end surface 200b of the molten raw material 200 may be before or after the melting of the molten raw material 200, as long as the load on the heating coil unit 11 does not change sharply with the placement of the molten raw material 201. Thus, the molten raw material 200 and the molten raw material 201 can be melted continuously while suppressing the change of the load on the heating coil unit 11. In addition, compared with the case of adjusting the timing of adding the molten raw material 201 by complex control, the control load can be reduced.

[0047] In addition, the support part 20 and the guide part 30 are respectively made of a non-magnetic body. Specifically, the support part 20 and the guide part 30 are made of a non-magnetic body and a material that is not inductively heated by the heating coil part 11. For example, the support part 20 and the guide part 30 are made of refractory bricks, heat-resistant resins, ceramics, etc. In addition, it is desirable that the guide part 30 is formed of a material having a higher mechanical strength and a higher heat resistance than the molten raw material 200 (201).

[0048] like Figure 2 to Figure 4 As shown, the support portion 20 has a shape (substantially a rectangular parallelepiped shape) that follows the shape of the molten raw material 200 .

[0049] In addition, in the first embodiment, if Figure 2 As shown in FIG. 1 , the raw material support surface portion 21 is configured to support the central portion C of the lower end 200a of the molten raw material 200 (see FIG. 1 ). Fig. 8A and Figure 8B ). Specifically, a through hole 22 is provided near the raw material supporting surface portion 21 of the supporting portion 20, through which the molten raw material 200 flows and falls after being melted. The through hole 22 extends in the vertical direction (Z direction). In addition, a plurality of (two in the first embodiment) through holes 22 are provided. Moreover, the raw material supporting surface portion 21 is composed of a portion of the supporting portion 20 located between the plurality of (two) through holes 22 (a portion between the through hole 22a and the through hole 22b). In detail, the molten raw material 200 before melting is supported by a portion of the upper surface of the supporting portion 20 excluding the through holes 22. In addition, as the melting of the molten raw material 200 progresses, the molten raw material 200 becomes a shape whose front end becomes thinner as it goes downward (refer to Fig. 8A and Figure 8B Then, the front end side of the molten raw material 200 in a state of being tapered is supported by the raw material support surface portion 21 formed by the portion between the plurality of (two) through holes 22 .

[0050] In addition, if Figure 3 As shown, the through hole 22 has a substantially circular shape when viewed from above. Moreover, the diameter d of the through hole 22 is larger than the width W of the raw material support surface 21 in the direction in which the plurality of through holes 22 are adjacent (the X direction). In addition, the two through holes 22 have the same shape (the same diameter) as each other. Moreover, for example, the diameter d is more than twice the width W. In addition, the diameter d of the through hole 22 is adjusted so that the melted raw material 200 after melting falls smoothly to the bottom through the through hole 22. In addition, the width W is adjusted so that the melted raw material 200 (refer to Figure 7 ) is stably supported.

[0051] In addition, if Figure 4As shown, the length L21 of the portion of the support portion 20 disposed inside the heating coil portion 11 is greater than the length L22 of the portion disposed outside the heating coil portion 11. In addition, the length L21 is adjusted depending on where the raw material support surface portion 21 is disposed inside the heating coil portion 11. Therefore, the length L21 may be smaller than the length L22. In addition, the length L21 of the portion disposed inside the heating coil portion 11 is adjusted to the most appropriate length depending on the type of the melted raw material 200.

[0052] (Analysis of magnetic flux density and Joule heat density)

[0053] Next, analysis (simulation) of the magnetic flux density and Joule heat density generated from the heating coil unit 11 will be described.

[0054] First, explain how Figure 5 As shown in FIG. 1 , the height position of the lower end 200a of the molten raw material 200 is made the same as the height position of the lower end 11b of the heating coil part 11 (approximately on the same plane). In this case, it was confirmed that the magnetic flux density (magnetic field) near the lower end 200a of the molten raw material 200 was relatively low, and the molten raw material 200 could not be fully melted. It is believed that the reason for this is that the magnetism was cut off by the side surface 200c of the molten raw material 200, and the magnetic flux did not fully reach the corner 200d of the lower end 200a of the molten raw material 200. In other words, the edge effect did not occur at the corner 200d, so the magnetic flux was not concentrated. It is believed that this caused the molten raw material 200 to not be fully melted and remain as a solid.

[0055] On the other hand, in Figure 6 When the lower end 200a of the molten raw material 200 is arranged above the lower end 11b of the heating coil part 11 by about 18% to 25% of the length of the heating coil part 11 as shown, it is confirmed that the magnetic flux density at the lower end 200a of the molten raw material 200 becomes relatively high. As a result, the magnetic flux fully reaches the corner 200d of the lower end 200a of the molten raw material 200, so that the edge effect occurs at the corner 200d. As a result, the magnetic flux is concentrated at the corner 200d, so it is confirmed that the molten raw material 200 can be completely melted.

[0056] In addition, if Figure 7 As shown, it is confirmed that since the magnetic flux is concentrated at the corner 200d, the Joule heat density (temperature) at the corner 200d becomes relatively high. Figure 7 The simulation results are shown in the case where the molten raw material 200 is divided into 1 / 4 and has a tapered shape. Figure 7It was confirmed that the smaller the distance between the melting material 200 and the heating coil unit 11, the higher the Joule heat density (temperature). In addition, it was confirmed that in the melting material 200 with a tapered shape, the distance between the front end (corner 200d) and the heating coil unit 11 was large, but on the other hand, the Joule heat density (temperature) became high due to the edge effect. It was confirmed that the melting material 200 was melted from the corner 200d of the melting material 200.

[0057] (Experiment on the configuration position of the material support surface)

[0058] Next, an experiment conducted to confirm the melting state of the molten raw material 200 corresponding to the arrangement position of the raw material support surface portion 21 inside the heating coil unit 11 will be described.

[0059] The material support surface portion 21 is arranged above the lower end 11b of the heating coil portion 11 and is smaller than the length L11 of the heating coil portion 11 in the vertical direction (see Figure 1 ), it was confirmed that the molten raw material 200 could not be sufficiently melted and the solid molten raw material 200 remained. On the other hand, when the raw material support surface portion 21 was arranged at a position of 18% or more of the length L11 of the heating coil portion 11 in the vertical direction above the lower end 11b of the heating coil portion 11, it was confirmed that the molten raw material 200 could be sufficiently melted.

[0060] (Experiment on continuous melting of molten raw materials)

[0061] exist Fig. 9 Detailed Description of the Invention An experiment conducted to confirm the change in electric power when seven molten raw materials 200 are continuously melted will be described below.

[0062] like Fig. 9 As shown in the figure, it was confirmed that when the molten raw material 200 to be melted was switched, some power fluctuation was observed, but the power was then stably controlled. It was confirmed that the power was more stably controlled, especially in the molten raw materials 200 after the third one. This is considered to be because the electrical components and the like included in the melting device 100 began to be thermally stable from around the time when the melting of the third molten raw material 200 started.

[0063] It was confirmed that the melting time required for melting each of the molten raw materials 200 was substantially the same for all seven molten raw materials 200. It was confirmed that the power increased relatively quickly after the high-frequency power supply board 1 was operated, and the melting of the first molten raw material 200 started relatively quickly. It was confirmed that the power decreased relatively quickly after the high-frequency power supply board 1 was stopped, and the melting of the seventh molten raw material 200 was completed relatively quickly.

[0064] Thus, by operating the high-frequency power supply plate 1 at an arbitrary timing to start melting the molten raw material 200 and stopping the high-frequency power supply plate 1 instantaneously when the required amount of molten raw material 200 is obtained, it is easy to melt the required amount of molten raw material 200 when necessary and take out the required amount of molten raw material 200 from the melting device 100. As a result, it is not necessary to hold a large amount of molten raw material 200 in the holding furnace 102 and to keep it warm. Thus, the size of the holding furnace 102 can be made relatively small. In addition, the molten raw material 200 after melting can be directly supplied from the melting device 100 to the die casting machine (not shown) without providing the holding furnace 102.

[0065] (Operation of the melting device)

[0066] Next, the operation of the melting device 100 will be described.

[0067] First, the high frequency power supply board 1 (refer to Figure 1 ) is turned on. This prepares the operation. Then, by operating the operating unit (not shown) provided on the high-frequency power supply board 1, heating by the heating coil unit 11 is started.

[0068] Then, if Fig. 8A As shown, due to the skin effect, the melting starts from the outer surface of the melting raw material 200. The melted melting raw material 200 falls to the bottom (outside the heating coil part 11) through the through hole 22 of the support part 20. In addition, due to the skin effect, the central part C of the melting raw material 200 melts slower than the outer surface of the melting raw material 200. Therefore, when the melting of the melting raw material 200 progresses, the melting raw material 200 changes into a shape in which the front end of the lower side of the melting raw material 200 becomes thinner. And the front end of the thinned melting raw material 200 is in a state supported by the raw material support surface part 21.

[0069] As melting progresses further, through edge effects (cf. Figure 7 ), the magnetic flux is concentrated on the front end of the molten raw material 200 whose front end is tapered. As a result, the front end of the molten raw material 200 is melted. As a result, Figure 8BAs shown, the molten raw material 200 falls downward due to its own weight. In addition, the falling molten raw material 200 is supported by the raw material support surface 21 of the support part 20, so the descent of the molten raw material 200 stops. Then, by continuously supplying high-frequency current to the heating coil part 11, Fig. 8A The status and Figure 8B The states shown are repeated alternately. Thus, the molten raw material 200 is continuously melted.

[0070] Here, when the supply of high-frequency current to the heating coil unit 11 is stopped, the heating of the molten raw material 200 is stopped immediately (within a few seconds). As a result, the descent of the melted molten raw material 200 is stopped instantly. In addition, when the supply of high-frequency current to the heating coil unit 11 is restarted in a state where the temperature of the molten raw material 200 is relatively high, melting starts immediately, and the descent of the melted molten raw material 200 restarts. In this way, by controlling the supply time of the high-frequency current to the heating coil unit 11, the amount of the melted molten raw material 200 can be controlled.

[0071] In addition, when the molten raw material 200 is melted by directly contacting the molten raw material 200 with the flame of the burner, which is different from the first embodiment, the molten raw material 200 may be oxidized (oxidation loss) due to the gas (oxygen, hydrogen) contained in the flame. Therefore, the yield of the melting is deteriorated. In addition, energy is required to keep the molten raw material 200 (melt) in a liquid state after melting, and personnel are also required to monitor the state of the melt. Therefore, in the first embodiment, the molten raw material 200 is melted by the heating coil unit 11 supplied with a high-frequency current, so that the molten raw material 200 will not be oxidized, thereby improving the yield of the melting (maintaining the quality). In addition, the energy used to keep the melt in a liquid state can be reduced.

[0072] In addition, unlike the first embodiment, when the molten raw material 200 is melted by making the crucible containing the molten raw material 200 directly contact the flame of the burner, it is difficult to heat the surface of the crucible evenly with the flame of the burner. As a result, the temperature distribution of the crucible is biased. As a result, the crucible is locally worn, so the crucible needs to be maintained. In addition, since the molten raw material 200 is indirectly heated through the crucible, the consumption of gas, oil, etc. as the raw material of the burner flame will increase. Therefore, in the first embodiment, the molten raw material 200 is melted by using the heating coil unit 11 supplied with high-frequency current, thereby being able to directly heat the molten raw material 200, thereby being able to suppress the increase in energy consumption.

[0073] [Effects of the First Embodiment]

[0074] In the first embodiment, the following effects can be obtained.

[0075] In the first embodiment, as described above, the melting device 100 is configured to include: the support portion 20 including the through hole 22 through which the melted raw material 200 flows and falls, and the support portion 20 supports the lower end 200a of the melted raw material 200 from below at a position above the lower end 11b of the heating coil portion 11; and the guide portion 30 guiding the melted raw material 201 so that the melted raw material 201 is inserted into the heating coil portion 11 in a state of being stacked in contact with the melted raw material 200. As a result, the lower end 200a of the melted raw material 200 is arranged above the lower end 11b of the heating coil portion 11, so that the magnetic flux from the heating coil portion 11 sufficiently reaches the lower end 200a of the melted raw material 200 and the portion near the lower end 200a. As a result, the lower end 200a of the molten raw material 200 and the portion near the lower end 200a can be quickly melted, so that the through hole 22 can be prevented from being blocked by the melt residue of the lower end 200a of the molten raw material 200. As a result, the molten raw material 200 can be smoothly flowed out from the through hole 22, and the molten raw material 200 can be prevented from scattering. As a result, the scattered molten raw material 200 can be prevented from adhering to the molten raw material 201. Here, when the molten raw material 201 is inserted into the heating coil unit 11 in a state where the molten raw material 201 is stacked in contact with the molten raw material 201, the magnetic flux from the heating coil unit 11 may not reach the molten raw material 201, and the molten raw material 201 is in a cold state. However, even in this case, since the scattering of the molten raw material 200 is suppressed, the scattered molten raw material 200 is suppressed from adhering to the molten raw material 201, and thus the movement of the molten raw material 201 can be suppressed from being hindered by the scattered molten raw material 200. Thus, it is not necessary to control the timing in such a way that the molten raw material 201 is inserted after the molten raw material 200 is melted and reduced to a predetermined size in order to make the molten raw material 201 in a heated state at the time of insertion. That is, even in the case where the molten raw material 201 is stacked with the molten raw material 200 and inserted into the heating coil unit 11 using the guide unit 30 before the molten raw material 200 is melted and reduced to a predetermined size, the molten raw material 201 can be smoothly inserted into the heating coil unit 11. As a result, the size of the heating object heated by the heating coil unit 11 can be made substantially constant. Thus, the load borne by the heating coil unit 11 can be made substantially constant. As a result, the molten raw material 200 and the molten raw material 201 can be melted stably and continuously.

[0076] In the first embodiment, as described above, the melting device 100 is configured such that the melting furnace 11a and the support 20 are provided independently of each other. Thus, the melting furnace 11a and the support 20 can be replaced independently, so that the maintenance of the melting furnace 11a and the support 20 can be facilitated. In addition, by replacing the support 20, the size (height) of the support 20 can be changed, so that the melting characteristics (melting speed, etc.) of the melting raw material 200 can be easily adjusted.

[0077] In the first embodiment, as described above, the melting device 100 is configured such that the support 20 is provided to be surrounded by the inner circumferential surface 11c of the melting furnace 11a. Thus, the movement of the support 20 is restricted by the inner circumferential surface 11c of the melting furnace 11a, thereby suppressing the position of the support 20 from being displaced.

[0078] In the first embodiment, as described above, the melting device 100 is configured such that the support portion 20 and the guide portion 30 are each made of a non-magnetic material that is not inductively heated by the heating coil portion 11. This can prevent the magnetic flux from the heating coil portion 11 from being affected by the support portion 20 and the guide portion 30, so that the melting material 200 can be stably melted by the heating coil portion 11.

[0079] In the first embodiment, as described above, the melting device 100 is configured such that the material support surface portion 21 supports the central portion C of the lower end 200a of the molten material 200 in a plan view. Here, when the molten material 200 is heated by the magnetic flux of the heating coil portion 11, the surface of the molten material 200 is mainly heated due to the skin effect. As a result, the molten material 200 starts to melt from the outer surface, and the central portion C of the molten material 200 melts at a relatively late stage. In other words, the melting progresses gradually from the outer surface of the molten material 200 to the center. In addition, the magnetic flux is concentrated on the lower end 200a (corner 200d) of the molten material 200, so the progress of the melting on the lower end 200a side is fast. As a result, the molten material 200 has a shape with a narrowing tip as it goes downward. Therefore, by configuring the material support surface portion 21 to support the center portion C of the lower end 200 a of the molten material 200 , the tapered front end (lower end 200 a ) of the molten material 200 can be supported in a stable state.

[0080] In the first embodiment, as described above, the melting device 100 is configured such that the raw material support surface portion 21 is formed by the portion of the support portion 20 located between the plurality of through holes 22. Thus, the plurality of through holes 22 are provided adjacent to the raw material support surface portion 21. Furthermore, the molten raw material 200 melted from the molten raw material 200 flows toward the front end side (the portion in contact with the raw material support surface portion 21) of the molten raw material 200 having a tapered shape, so that the melted molten raw material 200 can be made to fall more smoothly from the plurality of through holes 22 adjacent to the raw material support surface portion 21.

[0081] [Second embodiment]

[0082] Next, refer to Fig.10 The structure of the melting device 300 according to the second embodiment will be described. Unlike the first embodiment described above, in which the high-frequency power supply plate 1 is turned on or off manually, in the melting device 300 of the second embodiment, the turning on or off of the high-frequency power supply plate 1 is automated. In addition, for the same structure as the first embodiment described above, the same reference numerals as the first embodiment are attached and illustrated, and the description thereof is omitted.

[0083] like Fig.10 As shown, the melting device 300 includes a control device 40 for controlling the operation of the high-frequency power supply board 1 .

[0084] (Determines the melting time of the melting raw materials)

[0085] Next, the control for determining the melting time T for melting the raw material 200 will be described.

[0086] In the second embodiment, the melting device 100 (control device 40) is configured to determine the melting time T for melting the raw material 200 using the heating coil unit 11 based on the relationship between the predetermined melting amount of the raw material 200 and the supply amount of power from the high-frequency power supply plate 1, while the power supplied from the high-frequency power supply plate 1 to the heating coil unit 11 is set to be approximately fixed.

[0087] Specifically, when the preset melting amount of the molten raw material 200 is A (kg) and the melting speed determined by the power supply from the high-frequency power supply board 1 is B (kg / s), the melting time T (s) can be calculated using the following formula (1).

[0088] [Formula 1]

[0089] T=A / B…(1)

[0090] Then, the melting of the melting material 200 is automatically performed for the calculated melting time T (feedforward control). Specifically, the melting start time t1 is planned in advance, and the melting is automatically stopped at time t2 (t1+T) after the melting time T from the melting start time t1.

[0091] In addition, the other structures of the second embodiment are the same as those of the above-mentioned first embodiment.

[0092] (Effects of the Second Embodiment)

[0093] In the second embodiment, the following effects can be obtained.

[0094] In the second embodiment, as described above, the melting device 100 is configured such that, in a state where the power supplied from the high-frequency power board 1 to the heating coil unit 11 is set to be substantially constant, the melting time T for melting the raw material 200 by the heating coil unit 11 is determined based on the relationship between the melting amount of the raw material 200 and the power supply amount from the high-frequency power board 1 which is set in advance. Thus, a required amount of the raw material 200 can be melted without detecting the melting amount by a weight sensor or the like. As a result, the number of components for melting the raw material 200 can be reduced. In addition, compared with the case where the power of the high-frequency power board 1 is controlled based on the melting amount (feedback control), the control for melting the raw material 200 can be simplified.

[0095] In addition, the amount of power supplied from the high-frequency power supply board 1 is substantially constant, so that the load of control for determining the melting time T of the melting raw material 200 can be reduced compared to the case where the amount of power supplied varies. In addition, compared to the case where the melting time T is calculated (determined) manually by the user, the melting time T can be calculated accurately and quickly.

[0096] In addition, other effects of the second embodiment are the same as those of the above-mentioned first embodiment.

[0097] [Modifications]

[0098] In addition, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, not by the description of the above embodiments, and the scope of the present invention also includes all changes (modifications) within the meaning and scope equivalent to the claims.

[0099] In addition, in the first and second embodiments, the support portion 20 has two through holes 22 , but the present invention is not limited thereto. The support portion 20 may have one through hole 22 or three or more through holes 22 .

[0100] For example, Fig.11 and Fig.12 As shown, the melting device 400 includes a support portion 120 having a through hole 122. In this case, the molten raw material 200 is supported by a raw material support surface portion 121 (see Fig.12 ) supported.

[0101] In addition, a columnar portion may be provided near the center of a through hole. Fig.13 As shown, the support portion 220 includes a through hole 222 and a columnar portion 223. The columnar portion 223 is provided near the center of the through hole 222. The columnar portion 223 has a lower end 200a (see Figure 1 ) of the raw material support surface portion 221. In addition, the columnar portion 223 is connected to the inner peripheral surface 222a of the through hole 222 by a pair of beam portions 224.

[0102] In addition, in the first embodiment and the second embodiment, the guide portion 30 has an example of a cylindrical shape, but the present invention is not limited thereto. As long as the molten raw material 201 (second molten raw material) is stacked in contact with the molten raw material 200 (first molten raw material), the guide portion 30 may be a shape other than a cylindrical shape.

[0103] In addition, in the first embodiment and the second embodiment, the support portion 20 is shown as an example made of refractory bricks, but the present invention is not limited thereto. For example, the support portion 20 may also be made of ceramics.

[0104] In the second embodiment, the melting of the melting material 200 (first melting material) is automatically performed (feedforward control) according to the calculated melting time T, but the present invention is not limited thereto. For example, the melting time T may be manually set.

[0105] In addition, in the first embodiment and the second embodiment, an example in which the melting device of the present invention is used to melt the melting raw material 200 (first melting raw material) is shown, but the present invention is not limited to this. For example, by making the supply amount of high-frequency current relatively small, the melting device of the present invention can be used as a preheating device for removing water or oil adhering to the surface of the melting raw material 200 (first melting raw material) or a heating device for raw materials such as aluminum.

[0106] In addition, in the above-mentioned first embodiment and second embodiment, an example in which the melting raw material 200 (first melting raw material) has a substantially rectangular parallelepiped shape (prism shape) is shown, but the present invention is not limited thereto. For example, the melting raw material 200 (first melting raw material) may also have a substantially cylindrical shape. In this case, the heating coil unit 11 and the melting raw material 201 (second melting raw material) are also formed to have a substantially circular shape in a plan view so as to follow the melting raw material 200 (first melting raw material) having a substantially cylindrical shape.

[0107] In the first and second embodiments, the through hole 22 provided in the support portion 20 has a substantially circular shape, but the present invention is not limited thereto. For example, the through hole provided in the support portion may have a quadrilateral shape.

Claims

1. A melting device comprising: a heating coil portion into which the first molten raw material is inserted; a support portion including a through hole through which the first melted raw material flows after being melted and then falls, the support portion supporting the lower end of the first melted raw material from below at a position above the lower end of the heating coil portion; and a guide portion for guiding a second molten raw material melted after the first molten raw material is melted so that the second molten raw material is inserted into the heating coil portion in a state where the second molten raw material is stacked in contact with the first molten raw material, in, The support portion includes a raw material support surface portion, wherein the raw material support surface portion supports a lower end of the first molten raw material at a position above a lower end of the heating coil portion. The raw material support surface portion is configured to support the center portion of the lower end of the first molten raw material in a plan view. A plurality of through holes are provided, The material support surface portion is composed of a portion of the support portion located between the plurality of through holes.

2. The melting device according to claim 1, wherein: There are two through holes. The material support surface portion is constituted by a portion of the support portion located between the two material support surface portions.

3. The melting device according to claim 1, wherein: The raw material supporting surface portion supports the front end side of the molten raw material in a tapered state.

4. The melting device according to claim 1, wherein: The material support surface portion supports the lower end of the first molten material at a position above the lower end of the heating coil portion by a length that is 18% or more of a length of the heating coil portion in the vertical direction.

5. The melting device according to claim 4, wherein: The material support surface portion supports the lower end of the first molten material at a position above the lower end of the heating coil portion by a length that is at most 25% of a length of the heating coil portion in the vertical direction.

6. The melting device according to claim 1, wherein: The plurality of through holes each have a circular shape, The diameter of each of the plurality of through holes is larger than the width of the material support surface portion in a direction in which the plurality of through holes are adjacent to each other.

7. The melting device according to claim 6, wherein: The diameter of each of the plurality of through holes is at least twice the width.

8. The melting device according to claim 6, wherein: The diameters of the plurality of through holes are the same as each other.

9. The melting device according to claim 6, wherein: The plurality of through holes have the same shape as each other.

10. The melting device according to claim 6, wherein: The diameter of each of the plurality of through holes is adjusted so that the melted raw material can smoothly fall downward through the through holes.

11. The melting device according to claim 6, wherein: The molten raw material is stably supported in a state in which the diameters of the plurality of through holes are adjusted so as to be tapered.

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