Induction reactor and method for obtaining the status of the induction reactor

Abstract

To provide an induction furnace which makes it possible to acquire the state of the furnace without requiring the confirmation operation for the furnace by an operator with visual inspection or measurement or the like.SOLUTION: Provided is an induction furnace 100 which comprises a furnace body part 10 formed of a refractory and loaded with a melting raw material M inside, an induction heating coil 20 which is wound so as to surround the outer circumference of the furnace body part 10 to melt the melting raw material by induction heating and a control part 30. The control part 30 executes control of acquiring the state of the furnace based on the load resistance value or voltage of the induction heating coil 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an induction furnace and a method for obtaining the state of an induction furnace, and particularly to an induction furnace including a furnace body formed of a refractory and into which a melting raw material is charged inside, and a method for obtaining the state of the induction furnace.

Background Art

[0002] Conventionally, an induction furnace including a furnace body formed of a refractory and into which a melting raw material is charged inside has been known (for example, see Patent Document 1).

[0003] Patent Document 1 discloses an induction furnace including a furnace body formed of a refractory and into which a melting raw material is charged inside, and an induction coil. This induction furnace melts the melting raw material charged inside the furnace body by induction heating by an induction heating coil.

Prior Art Documents

Patent Documents

[0004]

Patent Document

Summary of the Invention

Problems to be Solved by the Invention

[0005] [End]] [End]]Here, although not described in Patent Document 1, in a conventional induction furnace, in order to obtain the state of the furnace such as the melting state of the melting raw material inside the furnace body and the deterioration state of the furnace body, it is necessary to perform a confirmation operation of the furnace by an operator such as visual inspection or measurement. Therefore, an induction furnace and a method for obtaining the state of the induction furnace that can obtain the state of the furnace without performing a confirmation operation of the furnace by an operator such as visual inspection or measurement are desired. [End]]

[0006] [End]] [End]]This invention was made to solve the above-mentioned problems, and one of its objectives is to provide an induction furnace and a method for acquiring the state of an induction furnace that can acquire the state of the furnace without requiring operators to perform furnace inspection work such as visual inspection or measurement. [Means for solving the problem]

[0007] To achieve the above objective, the induction furnace according to the first aspect of this invention comprises a furnace body formed of refractory material into which the raw material to be melted is introduced, an induction heating coil wound around the outer circumference of the furnace body and melting the raw material by induction heating, and based on the load resistance value or voltage of the induction heating coil, Create a graph showing the changes in the thickness of refractory materials. It comprises a control unit that performs the control, and

[0008] In the induction furnace described in the first phase above, the control unit performs control to acquire the furnace state based on the load resistance value or voltage of the induction heating coil, as described above. Here, the inventors of the present invention have focused on the fact that the load resistance value and voltage of the induction heating coil change in response to changes in the furnace state, such as the melting state of the raw material inside the furnace body and the deterioration state of the furnace body, and have found that the furnace state can be acquired by the control unit based on the relationship between the furnace state and the load resistance value of the induction heating coil. The furnace condition is represented by a graph showing the change in the thickness of the refractory material. As a result, the control unit acquires the furnace status based on the load resistance value or voltage of the induction heating coil, eliminating the need for operators to visually inspect or measure the furnace to obtain its status.

[0009] In the induction furnace according to the first aspect described above, preferably, the control unit performs control to acquire the state of the furnace, including at least one of the deterioration state of the furnace body and the melting state of the raw material inside the furnace body, based on the load resistance value of the induction heating coil. With this configuration, the control unit can acquire at least one of the deterioration state of the furnace body and the melting state of the raw material inside the furnace body without requiring operators to perform furnace inspection work.

[0011] An induction furnace according to the second aspect of this invention comprises a furnace body made of refractory material into which a molten material is introduced; an induction heating coil wound around the outer circumference of the furnace body and melting the molten material by induction heating; and a control unit that performs control to acquire the state of the furnace based on the load resistance value or voltage of the induction heating coil, wherein the control unit acquires the state of deterioration of the furnace body based on the change in the load resistance value at predetermined intervals. The control unit acquires the state of deterioration of the furnace body based on the change in the minimum value of the load resistance over a predetermined period, which is the change in the load resistance value over a predetermined period. With this configuration, even if an abnormally high load resistance value (noise) is acquired within the predetermined period, the influence of noise can be eliminated. As a result, the state of deterioration of the furnace body can be acquired with greater accuracy.

[0012] In the induction furnace according to the first aspect described above, preferably, the control unit acquires the melting state of the raw material inside the furnace body based on the change in the load resistance value per unit time during operation from the start of input of the raw material to the discharge of the molten metal. With this configuration, it is possible to acquire the change in the melting state of the raw material inside the furnace body while the induction furnace is in operation.

[0013] An induction furnace according to a third aspect of this invention comprises a furnace body formed of refractory material into which a molten material is introduced; an induction heating coil wound around the outer circumference of the furnace body and melting the molten material by induction heating; and a control unit that performs control to acquire the state of the furnace based on the load resistance value or voltage of the induction heating coil, wherein the control unit acquires the melting state of the molten material inside the furnace body based on the change in the load resistance value per unit time during operation from the start of introduction of the molten material to the discharge of the molten material. The control unit performs control to determine whether the amount of molten material inside the furnace body is insufficient, based on the decrease in the load resistance value per unit time during operation from the start of molten material input to the discharge of the molten material. With this configuration, if the control unit determines that the amount of molten material inside the furnace body is insufficient, it will input more molten material, thereby efficiently melting the material. As a result, the amount of molten material equivalent to the rated capacity of the furnace body can be melted in a shorter time, thus suppressing the increase in power consumption of the induction heating coil.

[0014] In this case, if the amount of molten material inside the furnace body remains insufficient for a predetermined period of time or longer, the control unit determines that the molten material is in a suspended state, where it does not fall because it forms an arch within the furnace body. With this configuration, the control unit can detect the suspended state without the operator having to visually confirm it. As a result, when the furnace enters a suspended state, the operator can quickly take measures to resolve the suspended state.

[0016] An induction furnace according to the fourth aspect of this invention comprises a furnace body made of refractory material into which a molten material is introduced; an induction heating coil wound around the outer circumference of the furnace body and melting the molten material by induction heating; and a control unit that performs control to acquire the state of the furnace based on the load resistance value or voltage of the induction heating coil.The induction heating coil system includes a plurality of induction heating coils arranged in a line along the depth direction of the furnace body. The control unit performs control based on the load resistance value of each of the plurality of induction heating coils to acquire at least one of the following: the state of deterioration of the furnace body corresponding to each position of the plurality of induction heating coils in the depth direction, and the state of melting of the raw material inside the furnace body corresponding to each position of the plurality of induction heating coils in the depth direction. With this configuration, when control is performed to acquire the state of deterioration of the furnace body corresponding to each position of the plurality of induction heating coils in the depth direction, it is possible to easily acquire localized deterioration (wear) and the locations of deterioration (wear) occurring in the furnace body, compared to when the state of deterioration of the entire furnace body is acquired based on the load resistance value of a single induction heating coil. Furthermore, when control is performed to acquire the state of melting of the raw material inside the furnace body corresponding to each position of the plurality of induction heating coils in the depth direction, changes in the melting state of the raw material in the depth direction can be acquired. As a result, abnormal locations inside the furnace body, such as shelf suspension, can be easily detected.

[0017] The above 2 In an induction furnace with this configuration, preferably, the control unit outputs acquired information about the furnace state, and the control unit further includes a notification unit that notifies the furnace state based on the information about the furnace state output by the control unit. With this configuration, the operator can easily grasp the furnace state through notification from the notification unit.

[0018] This invention 5 The method for obtaining the state of an induction furnace in a given phase includes an induction heating step in which the molten material is melted by induction heating of an induction heating coil wound around the outer circumference of the furnace body made of refractory material, an acquisition step in which the load resistance value of the induction heating coil is obtained, and based on the load resistance value obtained in the acquisition step, Create a graph showing the changes in the thickness of refractory materials. vinegar Rus It is equipped with a step.

[0019] The above 5In the method for obtaining the state of the induction furnace according to the above situation, as described above, the state of the furnace is obtained based on the load resistance value. Therefore, the state of the furnace can be obtained without performing the work of checking the furnace by an operator such as visual inspection or measurement. The furnace condition is represented by a graph showing the change in the thickness of the refractory material.

Advantages of the Invention

[0020] According to the present invention, as described above, it is possible to provide an induction furnace and a method for obtaining the state of the induction furnace capable of obtaining the state of the furnace without performing the work of checking the furnace by an operator such as visual inspection or measurement.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic diagram showing an induction furnace according to the first embodiment of the present invention. [Figure 2] It is a graph showing an example of the transition of the thickness of the refractory material (furnace body part). [Figure 3] It is a graph showing the relationship between the thickness of the furnace body part and the change rate of the load resistance value. [Figure 4] It is a diagram showing an example of the display by the display unit of the induction furnace according to the first embodiment. [Figure 5] It is a diagram showing an example of a graph of the transition of the thickness of the refractory material (furnace body part) displayed on the display unit of the first embodiment. [Figure 6] It is a diagram showing the correspondence between a graph showing the change of the load resistance value in one cycle and a graph showing the change of the change rate of the load resistance value in one cycle. [Figure 7] It is a diagram showing an example of the display in the state of insufficient material. [Figure 8] It is a diagram showing an example of the display in the suspended state. [Figure 9] It is a flowchart showing an example of the refractory thickness (wear degree) acquisition process by the control unit of the first embodiment. [Figure 10] It is a flowchart showing an example of the furnace internal state acquisition process by the control unit of the first embodiment. [Figure 11] It is a schematic diagram showing an induction furnace according to the second embodiment of the present invention. [Figure 12] This figure shows the change in load resistance value in the depth direction when localized wear occurs in an induction furnace according to the second embodiment. [Figure 13] This figure shows the change in load resistance value in the depth direction when a shelf suspension condition occurs in the induction furnace according to the second embodiment. [Modes for carrying out the invention]

[0022] The following describes embodiments of the present invention based on the drawings.

[0023] [First Embodiment] Referring to Figure 1, the overall configuration of the induction reactor 100 according to the first embodiment of the present invention will be described.

[0024] The induction furnace 100 comprises a furnace body 10, an induction heating coil 20, and a control unit 30. The induction furnace 100 also comprises a current detection unit 40 and a storage unit 50.

[0025] The furnace body 10 is made of refractory material, and the molten material M is introduced into it. The furnace body 10 is a crucible made of refractory material, for example, alumina or a ceramic material such as silica. The molten material M is, for example, a metal. The induction heating coil 20 is wound around the outer circumference of the furnace body 10 and melts the molten material M by induction heating. The molten material M melts inside the furnace body 10 to become molten metal Ma.

[0026] In this specification, the depth direction of the furnace body 10 is defined as the Y direction. The side of the furnace body 10 on which the furnace lid 11 is positioned is defined as the Y1 direction, and the side of the bottom wall 10a of the furnace body 10 is defined as the Y2 direction. Furthermore, one side in the X direction perpendicular to the Y direction is defined as the X1 direction, and the other side in the X direction is defined as the X2 direction. Molten metal Ma is discharged from the outlet 10b as the entire furnace body 10 tilts around an axis along the X direction.

[0027] The control unit 30 controls the entire induction furnace 100. The control unit 30 controls the furnace state based on the load resistance value of the induction heating coil 20. The control unit 30 also outputs the acquired furnace state information. In the first embodiment, the control unit 30 controls the furnace state by acquiring the deterioration state of the furnace body 10 (refractory material) and the melting state of the molten material M inside the furnace body 10. The control unit 30 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), etc. The control unit 30 is, for example, a processor.

[0028] The current detection unit 40 detects the current flowing through the induction heating coil 20. The control unit 30 performs feedback control to control the current flowing through the induction heating coil 20 based on the current value detected by the current detection unit 40. The control unit 30 also obtains the load resistance value of the induction heating coil 20 based on the current value detected by the current detection unit 40. Specifically, the control unit 30 calculates the load resistance value of the induction heating coil 20 by dividing the power consumption by the square of the current value.

[0029] The storage unit 50 includes non-volatile memory, a hard disk drive (HDD), or an SSD (Solid State Drive). The storage unit 50 stores programs for various controls performed by the control unit 30. The storage unit 50 also stores the load resistance value of the induction heating coil 20 acquired by the control unit 30.

[0030] The induction furnace 100 also includes a display unit 61, a warning lamp 62, and a buzzer 63. The display unit 61, warning lamp 62, and buzzer 63 notify the furnace status based on furnace status information output by the control unit 30. The display unit 61, warning lamp 62, and buzzer 63 are examples of the "notification unit" in the claims.

[0031] The display unit 61 notifies the operator of any abnormality in the melting state of the raw material M inside the furnace body 10 (furnace abnormality) by displaying an image. The display unit 61 includes, for example, a liquid crystal display or an organic EL display. The display unit 61 also displays the deterioration state of the furnace body 10 by image. Details of the display by the display unit 61 will be described later.

[0032] The warning lamp 62 lights up or flashes when an abnormality occurs in the melting state of the raw material M inside the furnace body 10, thereby notifying the operator of the abnormality in the melting state of the raw material M inside the furnace body 10.

[0033] The buzzer 63 notifies the operator by sound if an abnormality occurs in the melting state of the raw material M inside the furnace body 10.

[0034] The induction furnace 100 also includes an operating unit 70. The operating unit 70 includes an input device such as an operating panel or a touch panel provided on the display unit 61. The operating unit 70 receives input operations from an operator and outputs a signal based on the received input operations to the control unit 30.

[0035] Furthermore, the induction furnace 100 may be equipped with a weight measuring unit for measuring the weight of the molten raw material M containing molten metal Ma inside the furnace body 10.

[0036] The control unit 30 performs control to acquire the state of the furnace, including the deterioration state of the furnace body 10, based on the load resistance value of the induction heating coil 20. The control unit 30 also performs control to acquire the state of the furnace, including the melting state of the molten raw material M inside the furnace body 10, based on the load resistance value of the induction heating coil 20. In other words, in the first embodiment, the control unit 30 performs control to acquire the state of the furnace, including both the deterioration state of the furnace body 10 and the melting state of the molten raw material M inside the furnace body 10, based on the load resistance value of the induction heating coil 20.

[0037] (Acquisition and display of the deterioration status of the furnace body) The refractory material (furnace body 10) wears down and deteriorates as the induction furnace 100 operates. When the deterioration due to wear of the furnace body 10 progresses to a recommended standard value, relining (reconstruction of the furnace) is performed to rebuild the worn furnace body 10. Therefore, in order to determine the appropriate timing for relining (reconstruction of the furnace), it is necessary to obtain information on the deterioration state due to wear of the furnace body 10.

[0038] Here, as deterioration due to wear of the furnace body 10 progresses, the load resistance value of the induction heating coil 20 increases. Specifically, as the furnace body 10 wears down, its thickness decreases, and the distance between the induction heating coil 20 and the molten metal Ma (melting material M) shortens. As the distance between the induction heating coil 20 and the molten metal Ma (melting material M) shortens, the electrical coupling between the induction heating coil 20 and the molten metal Ma (melting material M) strengthens, resulting in an apparent increase in resistance. In other words, there is a correlation between the change in the thickness of the furnace body 10 and the load resistance value of the induction heating coil 20. Therefore, as melting is repeated and the refractory material (furnace body 10) wears down, the load resistance increases. As shown in Figure 2, when relining (reconstruction of the furnace) is performed to rebuild the worn furnace body 10, the thickness of the furnace body 10 increases (returning to the standard value), and the load resistance value of the induction heating coil 20 decreases.

[0039] Furthermore, in the design calculations for the furnace body 10 of the induction furnace 100, the load resistance value is calculated from the thickness of the furnace body 10 formed by refractory material (the distance between the induction heating coil 20 and the molten metal Ma). That is, load resistance values ​​corresponding to various thicknesses of the furnace body 10 are calculated. Based on the thickness of the furnace body 10 (the distance between the induction heating coil 20 and the molten metal Ma) and the calculated load resistance value, a graph like the one shown in Figure 3 can be created. Then, using a graph like the one shown in Figure 3, parameters for calculating the thickness of the refractory material (furnace body 10) from the load resistance value of the induction heating coil 20 can be obtained.

[0040] The control unit 30 acquires the state of deterioration of the furnace body 10 based on the change in the load resistance value at predetermined intervals. Specifically, the control unit 30 acquires the state of deterioration of the furnace body 10 based on the change in the minimum value of the load resistance value at predetermined intervals, which is the change in the load resistance value at predetermined intervals. For example, the control unit 30 acquires the minimum value of the load resistance value for each operating day of the induction furnace 100. The control unit 30 then stores the acquired minimum value of the load resistance value for each operating day in the storage unit 50. Based on the minimum value of the load resistance value for each operating day stored in the storage unit 50, the control unit 30 acquires the thickness of the refractory material (furnace body 10) and creates a progression of the thickness (abrasion degree) of the refractory material for each operating day. Specifically, the control unit 30 creates a progression of the thickness of the refractory material for each operating day, with the thickness of the refractory material before abrasion, such as during furnace construction or relining (reconstruction), set to 100% (reference value).

[0041] As shown in Figure 4, the display unit 61 shows an image 61a indicating the power consumption of the induction furnace 100. In addition to the power consumption of the induction furnace 100, image 61a also shows the degree of wear of the refractory material (furnace body 10). In the example shown in Figure 4, the degree of wear of the refractory material (furnace body 10) is shown as "95%", which is the ratio of the current thickness of the refractory material to the standard thickness of the refractory material.

[0042] Furthermore, by performing an operation to check the "transition details" via the operation unit 70, the operator can grasp the changes in the thickness (abrasion) of the refractory material day by day. Specifically, as shown in Figure 5, a graph 61b showing the changes in the thickness of the refractory material day by day, created by the control unit 30, is displayed on the display unit 61 under the control of the control unit 30. The operator can then easily grasp the changes in the thickness of the refractory material day by day by visually checking the graph 61b showing the changes in the thickness of the refractory material day by day displayed on the display unit 61, or the numerical value based on the thickness (abrasion) of the refractory material displayed on the display unit 61. Note that although the vertical axis of graph 61b (see Figure 5) shows the thickness of the refractory material, the vertical axis may also show the abrasion.

[0043] The control unit 30 acquires the melting state of the raw material M inside the furnace body 10 based on the change in the load resistance value per unit time during operation from the start of inputting the raw material M to the discharge of the molten metal. Specifically, the control unit 30 performs control to determine whether or not there is an insufficient amount of raw material M inside the furnace body 10 based on the decrease in the load resistance value per unit time during operation from the start of inputting the raw material M to the discharge of the molten metal.

[0044] (Acquisition and display of furnace conditions) Here, as the molten raw material M melts into molten metal Ma, the volume of the molten raw material M introduced into the furnace body 10 decreases compared to before melting. When the volume of the molten raw material M, including the molten metal Ma, is small relative to the rated capacity of the furnace body 10, the electrical coupling weakens and the apparent resistance decreases. In other words, when the molten raw material M is sufficiently introduced relative to the rated capacity of the furnace body 10, the load resistance value of the induction heating coil 20 increases. On the other hand, when the molten raw material M is not sufficiently introduced relative to the rated capacity of the furnace body 10, the load resistance value of the induction heating coil 20 decreases.

[0045] The control unit 30 acquires the load resistance value of the induction heating coil 20 at predetermined time intervals during one cycle (one charge), from the start of feeding the molten raw material M into the furnace body 10 until the molten raw material M equivalent to the rated capacity of the induction furnace 100 becomes molten Ma and is discharged from the outlet 10b. The control unit 30 acquires the load resistance value of the induction heating coil 20 at predetermined time intervals, for example, every few minutes to every few seconds. The control unit 30 also acquires the load resistance value at predetermined time intervals when the rated power is applied. Furthermore, the control unit 30 controls the system to store the minimum load resistance value in the storage unit 50 for each cycle, assuming that the furnace body 10 contains the rated weight of molten raw material M (molten Ma) and the rated power is applied. The weight of the molten raw material M may be obtained by measuring the height of the molten metal Ma using a sensor, or by inputting the weight of the molten raw material M that the operator has put into the furnace body 10. Furthermore, if the induction furnace 100 is equipped with a weight measuring unit for measuring the weight of the molten raw material M, the weight of the molten raw material M may be obtained based on the measurement results of the weight measuring unit. Regarding power acquisition, for example, point-of-use power may be used. The control unit 30 then performs control to store the lowest load resistance value for one operating day among the lowest load resistance values ​​for each cycle in the storage unit 50.

[0046] The control unit 30 then determines that there is a shortage of molten raw material M inside the furnace body 10 and issues a furnace abnormality alarm if the rate of decrease in the load resistance value per unit time during operation from the start of input of the molten raw material M to the discharge of the molten material exceeds a predetermined material shortage threshold. In the example shown in Figure 6, a furnace abnormality alarm is issued at elapsed times t1, t3, and t5, respectively, when the rate of change of the load resistance value changes in the negative direction from the value measured in the previous measurement to exceed the predetermined material shortage threshold.

[0047] The display unit 61 indicates that the furnace is in a material-deficient state based on the furnace status information output by the control unit 30. Specifically, if the control unit 30 determines that the amount of molten raw material M inside the furnace body 10 is insufficient, the control unit 30 controls the display unit 61 to display an image 61c with "Material Deficient" in the info field as a furnace abnormality alarm, as shown in Figure 7. In addition, if the control unit 30 determines that the furnace is in a material-deficient state, the warning lamp 62 and buzzer 63 will be activated by the control unit 30 as a furnace abnormality alarm.

[0048] Furthermore, if the load resistance value per unit time during operation from the start of adding the dissolving raw material M to the discharge of the molten metal begins to rise due to the addition of the dissolving raw material M, the control unit 30 performs control to cancel the furnace abnormality alarm. In the example shown in Figure 6, the control unit 30 performs control to cancel the furnace abnormality alarms issued at elapsed times t1, t3, and t5, respectively, at elapsed times t2, t4, and t6.

[0049] Furthermore, the control unit 30 performs control to determine whether the amount of molten material M is insufficient, and whether the molten material M (molten material Mb) is in a suspended state (see Figure 13) where it does not fall, due to the formation (construction) of an arch within the furnace body 10. Specifically, the molten material Mb forms an arch within the furnace body 10 as multiple molten material Ms become entangled due to eddy currents generated by induction heating flowing to the point contact points between multiple molten material Ms, causing the multiple molten material Ms to be spot-welded together.

[0050] The control unit 30 performs control to determine that the furnace is in a suspended state if the amount of molten material M inside the furnace body 10 remains insufficient for a predetermined period of time or longer. Specifically, the control unit 30 determines that the furnace is in a suspended state if the amount of molten material M inside the furnace body 10 remains insufficient for a predetermined period of time or longer. Alternatively, the control unit 30 may also determine that the furnace is in a suspended state if the amount of molten material M inside the furnace body 10 remains insufficient for a predetermined period of time or longer, AND the decrease in the load resistance value per unit time during operation from the start of input of molten material M to the discharge of molten material exceeds a predetermined suspended threshold value which is set to be greater than a predetermined material deficiency threshold.

[0051] The display unit 61 displays that the furnace is in a suspended state based on the furnace status information output by the control unit 30. Specifically, when the control unit 30 determines that the furnace is in a suspended state, the control unit 30 controls the display unit 61 to display an image 61d with "Suspension Occurred" in the info field as a furnace abnormality alarm, as shown in Figure 8. In addition, when the control unit 30 determines that the furnace is in a suspended state, the warning lamp 62 and buzzer 63 continue to provide notification as a furnace abnormality alarm. The notification by the warning lamp 62 changes the notification method by changing the color of the lamp that lights up or flashes, or by switching between lighting and flashing, depending on whether the furnace is determined to be in a low material state or in a suspended state. The notification by the buzzer 63 also changes the notification method by changing the sound emitted depending on whether the furnace is determined to be in a low material state or in a suspended state. The control unit 30 can switch on or off whether the display unit 61, warning lamp 62, and buzzer 63 provide notification.

[0052] Then, if a predetermined time limit is exceeded after the control unit 30 issues an in-furnace abnormality alarm, the control unit 30 controls the induction furnace 100 to stop operation. Specifically, the control unit 30 controls the induction heating by the induction heating coil 20 to stop.

[0053] (Refractory thickness acquisition process) Referring to Figure 9, the processing flow of the refractory thickness (abrasion degree) acquisition process by the control unit 30 will be explained.

[0054] In step S1, the induction furnace 100 begins induction heating using the induction heating coil 20. In step S1, the raw material M to be melted is melted by induction heating of the induction heating coil 20, which is wound around the outer circumference of the furnace body 10, which is made of refractory material. Step S1 is an example of the "induction heating step" in the claims.

[0055] In step S2, the load resistance value of the induction heating coil 20 is obtained. The control unit 30 calculates the load resistance value of the induction heating coil 20 using the current value of the induction heating coil 20 detected by the current detection unit 40. Step S2 is an example of the "obtaining step" in the claims.

[0056] In step S3, the minimum load resistance value is obtained. In step S3, the control unit 30 obtains the minimum load resistance value for each predetermined period, such as each working day, from the load resistance values ​​it has calculated (obtained). The minimum load resistance values ​​for each predetermined period obtained by the control unit 30 are then stored in the storage unit 50.

[0057] In step S4, the thickness (abrasion) of the refractory material is obtained. In step S4, the control unit 30 obtains the thickness of the refractory material (furnace body 10) as the deterioration state (furnace state) of the furnace body 10, based on the load resistance values ​​obtained in steps S2 to S3. Specifically, the control unit 30 creates a graph of the refractory material thickness progression (see Figure 5) by plotting the thickness of the refractory material for each predetermined period, obtained based on the minimum load resistance value for each predetermined period (operating days) stored in the memory unit 50. Step S4 is an example of the "state acquisition step" in the claims.

[0058] (Process to acquire furnace state) Referring to Figure 10, the processing flow of the furnace state acquisition process by the control unit 30 will be explained.

[0059] In step S11, the induction furnace 100 begins induction heating using the induction heating coil 20. In step S11, the raw material M to be melted is melted by induction heating of the induction heating coil 20, which is wound around the outer circumference of the furnace body 10, which is made of refractory material. Step S11 is an example of the "induction heating step" in the claims.

[0060] In step S12, the load resistance value of the induction heating coil 20 is obtained. Step S12 is an example of the "obtaining step" in the claims.

[0061] In step S13, the furnace state is acquired. In step S13, based on the load resistance value acquired in step S12, the control unit 30 acquires the melting state (furnace state) of the molten material M inside the furnace body 10. Step S13 is an example of the "state acquisition step" in the claims.

[0062] In step S14, it is determined whether or not there is a shortage of material. In step S14, as described above, the control unit 30 performs control to determine whether or not there is a shortage of molten material M inside the furnace body 10, based on the decrease in the load resistance value per unit time during operation from the start of input of molten material M to the discharge of molten material. If it is determined in step S14 that there is a shortage of material, the process proceeds to step S15. If it is determined in step S14 that there is no shortage of material, the process in step S14 is repeated.

[0063] In step S15, a material shortage is reported. In step S15, the control unit 30 controls the display unit 61, warning lamp 62, and buzzer 63 to report the material shortage, as described above.

[0064] In step S16, it is determined whether the material shortage condition has continued for a predetermined time or longer. In step S16, as described above, the control unit 30 performs control to determine that the state of insufficient molten material M inside the furnace body 10 is a shelf-suspended state if it has continued for a predetermined time or longer. If it is determined in step S16 that the material shortage condition has continued for a predetermined time or longer, the processing step proceeds to step S17. If it is determined in step S16 that the material shortage condition has not continued for a predetermined time or longer, the processing step returns to step S14.

[0065] In step S17, it is notified that the product is in a suspended state. In step S17, the control unit 30 controls the display unit 61, warning lamp 62, and buzzer 63 to notify the product of the suspended state as described above.

[0066] In step S18, it is determined whether the internal furnace abnormality has continued for a predetermined time or longer. In step S18, as described above, the control unit 30 performs control to determine whether a time exceeding a predetermined shutdown threshold has elapsed since the control to issue an internal furnace abnormality alarm. If, in step S18, a time exceeding the predetermined shutdown threshold has elapsed since the control to issue an internal furnace abnormality alarm was performed, and it is determined that the internal furnace abnormality has continued for a predetermined time or longer, the process steps proceed to step S19. If, in step S18, it is determined that the internal furnace abnormality has not continued for a predetermined time or longer, the process steps return to step S14.

[0067] In step S19, the operation of the induction reactor 100 is stopped. In step S19, the operation of the induction reactor 100 is stopped by the control of the control unit 30.

[0068] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0069] In the first embodiment, the furnace state is obtained based on the load resistance value of the induction heating coil 20. As a result, the furnace state is obtained by the control unit 30 based on the load resistance value of the induction heating coil 20, so the furnace state can be obtained without the need for operators to visually inspect or measure the furnace.

[0070] Furthermore, in the first embodiment, as described above, the control unit 30 performs control to acquire the state of the furnace, including both the state of deterioration of the furnace body 10 and the state of melting raw material M inside the furnace body 10, based on the load resistance value of the induction heating coil 20. As a result, the control unit 30 can acquire both the state of deterioration of the furnace body 10 and the state of melting raw material M inside the furnace body 10 without requiring an operator to check the furnace. Moreover, both the state of deterioration of the furnace body 10 and the state of melting raw material M inside the furnace body 10 can be acquired based on the load resistance value of the induction heating coil 20. As a result, it is possible to acquire both the state of deterioration of the furnace body 10 and the state of melting raw material M inside the furnace body 10 more easily than when acquiring them based on different indicators.

[0071] Furthermore, in the first embodiment, as described above, the control unit 30 acquires the state of deterioration of the furnace body 10 based on the change in the load resistance value at predetermined intervals. This makes it possible to acquire the progression of deterioration of the furnace body 10 from the change in the load resistance value at predetermined intervals.

[0072] Furthermore, in the first embodiment, as described above, the control unit 30 acquires the state of deterioration of the furnace body 10 based on the change in the minimum value of the load resistance value for each predetermined period, which is the change in the load resistance value for each predetermined period. This makes it possible to eliminate the influence of noise even if an abnormally high load resistance value (noise) is acquired within the predetermined period. As a result, the state of deterioration of the furnace body 10 can be acquired with greater accuracy.

[0073] Furthermore, in the first embodiment, as described above, the control unit 30 acquires the melting state of the melting material M inside the furnace body 10 based on the change in the load resistance value per unit time during operation from the start of input of the melting material M to the discharge of the molten metal. This makes it possible to acquire the change in the melting state of the melting material M inside the furnace body 10 while the induction furnace 100 is in operation.

[0074] Furthermore, in the first embodiment, as described above, the control unit 30 performs control to determine whether the amount of molten raw material M inside the furnace body 10 is insufficient, based on the decrease in the load resistance value per unit time during operation from the start of inputting the molten raw material M to the discharge of the molten material. As a result, when the control unit 30 determines that the amount of molten raw material M inside the furnace body 10 is insufficient, the molten raw material M is added, thereby efficiently melting the molten raw material M. As a result, the molten raw material M equivalent to the rated capacity of the furnace body 10 can be melted in a shorter time, thus suppressing an increase in the power consumption of the induction heating coil 20.

[0075] Furthermore, in the first embodiment, as described above, if the amount of molten material M inside the furnace body 10 remains insufficient for a predetermined time or longer, the control unit 30 determines that the molten material M is in a suspended state where it does not fall, by forming an arch inside the furnace body 10. As a result, the control unit 30 can detect that the molten material is in a suspended state without the operator having to visually confirm it. Consequently, when the furnace enters a suspended state, the operator can quickly take measures to resolve the suspended state.

[0076] Furthermore, in the first embodiment, as described above, the control unit 30 outputs information about the furnace status that it has acquired. The induction furnace 100 is equipped with a display unit 61, a warning lamp 62, and a buzzer 63 that notify the furnace status based on the furnace status information output by the control unit 30. As a result, the operator can easily understand the furnace status through notifications from the display unit 61, the warning lamp 62, and the buzzer 63.

[0077] [Second Embodiment] The configuration of the induction furnace 200 according to the second embodiment of the present invention will be described with reference to Figures 11 to 13. Components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0078] In the second embodiment, as shown in Figure 11, the induction furnace 200 includes induction heating coils 220 and a detection unit 240. The induction heating coils 220 include induction heating coils 21, 22, 23, 24, 25, 26, 27, and 28 arranged in a line along the depth direction (Y direction) of the furnace body 10. Note that induction heating coils 21, 22, 23, 24, 25, 26, 27, and 28 are examples of the "multiple induction heating coils" in the claims.

[0079] Furthermore, the detection unit 240 includes detectors 41, 42, 43, 44, 45, 46, 47, and 48, which are provided in correspondence with the induction heating coils 21, 22, 23, 24, 25, 26, 27, and 28, respectively.

[0080] The control unit 30 of the induction furnace 200 acquires the load resistance value of each of the induction heating coils 21 to 28. The control unit 30 of the induction furnace 200 also acquires the total load resistance value of the induction heating coil 220 from the load resistance values ​​of each of the induction heating coils 21 to 28. This makes it possible to acquire the deterioration state of the furnace body 10 at positions corresponding to each of the induction heating coils 21 to 28 in the depth direction (Y direction), and the melting state of the molten material M inside the furnace body 10, as well as the deterioration state of the entire furnace body 10 and the melting state of the molten material M inside the entire furnace body 10.

[0081] In the second embodiment, the control unit 30 performs control to acquire the deterioration state of the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction (Y direction) based on the respective load resistance values ​​of the induction heating coils 21 to 28.

[0082] As shown in Figure 12, if localized wear K occurs in the inner wall 10c of the furnace body 10 at a location corresponding to the induction heating coil 26, and the thickness of the furnace body 10 (refractory material) at that location is smaller than at other locations, the distance between the molten metal Ma and the induction heating coil 26 becomes shorter than at other locations. As a result, the load resistance value of the induction heating coil 26 becomes larger than that of the induction heating coils 21-26 and 28. This makes it possible to identify the location where localized wear K is occurring in the depth direction (Y direction).

[0083] Furthermore, in the second embodiment, the control unit 30 performs control to acquire the melting state of the molten raw material M inside the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction (Y direction), based on the respective load resistance values ​​of the induction heating coils 21 to 28.

[0084] The load resistance value in the area where the molten raw material Mb is suspended is greater than the load resistance value in the area where the molten raw material M has become molten metal Ma. Specifically, in the example shown in Figure 13, the load resistance value of induction heating coil 22 is greater than the load resistance values ​​of induction heating coils 24-28. Also, the load resistance value of the air region A1 formed between the area where the molten raw material Mb is suspended and the area where the molten raw material M has become molten metal Ma is smaller than the load resistance value of the area where the molten raw material M has become molten metal Ma. Furthermore, the load resistance value of the air region A2 formed on the Y1 side of the area where the molten raw material Mb is suspended is smaller than the load resistance value of the area where the molten raw material M has become molten metal Ma. Specifically, in the example shown in Figure 13, the load resistance values ​​of induction heating coils 21 and 23 are smaller than the load resistance values ​​of induction heating coils 24-28.

[0085] Furthermore, it is possible to estimate whether or not it is molten metal Ma based on the weight of the molten raw material M introduced into the furnace body 10 and the amount of electricity used (amount of energy supplied). Specifically, the temperature of the molten raw material M can be calculated by dividing the weight of the molten raw material M by the amount of electricity used, and the physical properties of the molten raw material M, thereby estimating the state of the molten raw material M. As a result, the melting state of the molten raw material M can be estimated by the control unit 30 at each position of the induction heating coils 21 to 28 in the depth direction (Y direction).

[0086] The other configurations of the second embodiment are the same as those of the first embodiment described above.

[0087] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0088] In the second embodiment, similar to the first embodiment, the state of the furnace can be obtained without requiring workers to perform inspections of the furnace, such as visual inspection or measurement.

[0089] Furthermore, in the second embodiment, as described above, the induction heating coil 220 includes induction heating coils 21 to 28 arranged in a line along the depth direction (Y direction) of the furnace body 10. The control unit 30 then performs control to acquire both the deterioration state of the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction, and the melting state of the molten raw material M inside the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction, based on the respective load resistance values ​​of the induction heating coils 21 to 28. As a result, the deterioration state of the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction is acquired, making it easier to detect localized wear K occurring in the furnace body 10 and the locations where localized wear K occurs, compared to the case where the deterioration state of the entire furnace body 10 is acquired based on the load resistance value of a single induction heating coil. Furthermore, since the melting state of the raw material M inside the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction is acquired, changes in the melting state of the raw material M in the depth direction can be acquired. As a result, abnormal areas inside the furnace body 10, such as shelf-suspended states, can be easily detected.

[0090] Other effects of the second embodiment are the same as those of the first embodiment described above.

[0091] [Differentiation] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications (modifications) within the meaning and scope equivalent to the claims.

[0092] For example, in the first and second embodiments described above, an example was shown in which control is performed to acquire the state of the furnace, including both the state of deterioration of the furnace body 10 and the state of melting of the raw material M inside the furnace body 10, based on the load resistance value of the induction heating coil 20. However, the present invention is not limited thereto. For example, the control unit may acquire only the state of deterioration of the furnace body as the state of the furnace, based on the load resistance value of the induction heating coil. Alternatively, the control unit may acquire only the state of melting of the raw material inside the furnace body as the state of the furnace, based on the load resistance value of the induction heating coil.

[0093] Furthermore, in the first and second embodiments described above, the control unit 30 was shown to acquire the state of deterioration of the furnace body 10 based on the change in the load resistance value at predetermined intervals, but the present invention is not limited thereto. In the present invention, the state of deterioration of the furnace body may be acquired by comparing the load resistance value with a preset threshold. In this case, if the control unit determines, by comparing the load resistance value with a preset threshold, that the state of deterioration of the furnace body exceeds the criteria for relining (reconstruction of the furnace), the notification unit may provide notification.

[0094] Furthermore, in the first and second embodiments described above, the control unit 30 was shown to acquire the state of deterioration of the furnace body 10 based on the change in the minimum value of the load resistance value for each predetermined period, which is the change in the load resistance value for each predetermined period. However, the present invention is not limited to this. In the present invention, the control unit may acquire the state of deterioration of the furnace body based on the change in the average value of the load resistance value for each predetermined period.

[0095] Furthermore, in the first and second embodiments described above, the control unit 30 is shown to perform control to determine whether or not the amount of molten raw material M inside the furnace body 10 is insufficient, based on the decrease in the load resistance value per unit time during operation from the start of inputting the molten raw material M until the discharge of the molten material. However, the present invention is not limited thereto. In the present invention, the control unit may perform control to determine whether or not the amount of molten raw material inside the furnace body is insufficient, based on the load resistance value with respect to the elapsed time from the start of inputting the molten material.

[0096] Furthermore, in the first and second embodiments described above, the control unit 30 is shown to perform control to determine that the furnace is in a suspended state if the amount of molten raw material M inside the furnace body 10 remains insufficient for a predetermined time or longer, but the present invention is not limited thereto. In the present invention, the control unit may determine the insufficient amount of molten raw material inside the furnace body and the suspended state separately.

[0097] Furthermore, in the second embodiment described above, the control unit 30 is shown to perform control to acquire both the deterioration state of the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction, and the melting state of the raw material M inside the furnace body 10 corresponding to each position of the induction heating coils 21 to 28 in the depth direction. However, the present invention is not limited to this. In the present invention, the control unit may acquire only the deterioration state of the furnace body corresponding to each position of the plurality of induction heating coils in the depth direction. Alternatively, the control unit may acquire only the melting state of the raw material inside the furnace body corresponding to each position of the plurality of induction heating coils in the depth direction.

[0098] Furthermore, in the second embodiment described above, the induction furnace 200 was shown to include eight coils (induction heating coils 21-28) arranged in a line along the depth direction (Y direction) of the furnace body 10, but the present invention is not limited to this. In the present invention, the number of induction heating coils arranged in a line along the depth direction of the furnace body may be two to seven, or nine or more.

[0099] Furthermore, in the first and second embodiments described above, the induction furnace 100 is shown to be equipped with a display unit 61, a warning lamp 62, and a buzzer 63 that notify the furnace status based on the furnace status information output by the control unit 30, but the present invention is not limited thereto. In the present invention, the furnace status information output by the control unit may be acquired by an information terminal such as a PC (Personal Computer), tablet terminal, or smartphone, which is provided separately from the induction furnace, and the furnace status may be notified by the information terminal provided separately from the induction furnace.

[0100] Furthermore, in the first and second embodiments described above, for the sake of explanation, a flow-driven flowchart was used to describe the refractory thickness (wear degree) acquisition process and the furnace state acquisition process according to the present invention, in which the processes are carried out sequentially according to the processing flow. However, the present invention is not limited thereto. In the present invention, the processing operations in the refractory thickness acquisition process and the furnace state acquisition process may be carried out by event-driven processing, in which processing is performed on an event-by-event basis. In this case, the processing operations in the refractory thickness acquisition process and the furnace state acquisition process may be carried out entirely by event-driven processing, or by a combination of event-driven and flow-driven processing.

[0101] Furthermore, in the first and second embodiments described above, the control unit 30 was shown to acquire deterioration due to wear of the furnace body 10 as a deterioration state of the furnace body 10, but the present invention is not limited to this. In the present invention, the control unit may acquire deterioration other than wear, such as cracking, as a deterioration state of the furnace body.

[0102] Furthermore, while the first and second embodiments described above show examples in which the furnace state is obtained based on the load resistance value of the induction heating coil 20, the present invention is not limited thereto. In the present invention, the furnace state, such as the deterioration state of the furnace body and the melting state of the raw material inside the furnace body, may be obtained based on the voltage of the induction heating coil. In this case, since the furnace state is obtained by the control unit based on the voltage of the induction heating coil, the furnace state can be obtained without the need for operators to perform furnace inspection work such as visual inspection or measurement. [Explanation of Symbols]

[0103] 10 Furnace body 10c inner wall 20, 220 induction heating coils 21-28 Induction heating coil 30 Control Unit 61 Display Unit (Notification Unit) 62 Warning lights (notification unit) 63 Buzzer (News Department) 100, 200 induction furnace M Dissolve raw materials

Claims

1. The furnace body is made of refractory material and into which the molten material is introduced, An induction heating coil is wound around the outer circumference of the furnace body and melts the raw material by induction heating, An induction furnace comprising: a control unit that performs control to create a graph showing the change in the thickness of the refractory material based on the load resistance value or voltage of the induction heating coil.

2. The induction furnace according to claim 1, wherein the control unit acquires the state of deterioration of the furnace body based on the change in the load resistance value at predetermined intervals.

3. A furnace body made of refractory material into which the molten material is introduced, An induction heating coil is wound around the outer circumference of the furnace body and melts the raw material by induction heating, The system includes a control unit that performs control to acquire the state of the furnace based on the load resistance value or voltage of the induction heating coil, The control unit acquires the deterioration status of the furnace body based on the change in the load resistance value at predetermined intervals. An induction furnace in which the control unit acquires the state of deterioration of the furnace body based on the change in the minimum value of the load resistance for each predetermined period, which is the change in the load resistance value for each predetermined period.

4. The induction furnace according to claim 1, wherein the control unit acquires the melting state of the raw material inside the furnace body based on the change in the load resistance value per unit time during operation from the start of inputting the raw material to the discharge of the molten metal.

5. A furnace body made of refractory material into which the molten material is introduced, An induction heating coil is wound around the outer circumference of the furnace body and melts the raw material by induction heating, The system includes a control unit that performs control to acquire the state of the furnace based on the load resistance value or voltage of the induction heating coil, The control unit acquires the melting state of the raw material inside the furnace body based on the change in the load resistance value per unit time during operation from the start of inputting the raw material to the discharge of the molten metal. The control unit performs control to determine whether the amount of molten raw material inside the furnace body is insufficient, based on the decrease in the load resistance value per unit time during operation from the start of inputting the molten raw material to the discharge of the molten metal.

6. The induction furnace according to claim 5, wherein the control unit performs control to determine that the material to be melted is in a suspended state in which the material to be melted does not fall, if the amount of material to be melted inside the furnace body remains insufficient for a predetermined time or longer, by forming an arch within the furnace body.

7. A furnace body made of refractory material into which the molten material is introduced, An induction heating coil is wound around the outer circumference of the furnace body and melts the raw material by induction heating, The system includes a control unit that performs control to acquire the state of the furnace based on the load resistance value or voltage of the induction heating coil, The induction heating coil includes a plurality of induction heating coils arranged in a line along the depth direction of the furnace body, An induction furnace in which the control unit performs control to obtain at least one of the deterioration state of the furnace body corresponding to each of the positions of the plurality of induction heating coils in the depth direction, and the melting state of the raw material inside the furnace body corresponding to each of the positions of the plurality of induction heating coils in the depth direction, based on the load resistance value of each of the plurality of induction heating coils.

8. The control unit outputs the acquired information on the state of the furnace. The induction furnace according to claim 3, 5, or 7, further comprising a notification unit that notifies the state of the furnace based on information about the state of the furnace output by the control unit.

9. An induction heating step in which the raw material to be melted is melted by induction heating of an induction heating coil wound around the outer circumference of the furnace body, which is made of refractory material, The acquisition step involves obtaining the load resistance value of the induction heating coil, A method for acquiring the state of an induction furnace, comprising the step of creating a graph showing the change in the thickness of the refractory material based on the load resistance value acquired in the acquisition step.

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