Method for controlling material feeding in non-ferrous metal melting furnace and non-ferrous metal melting furnace

Abstract

To provide a control method capable of preventing molten metal from being oxidized by controlling material feeding based on detection of a single molten metal surface level, and a non-ferrous metal melting furnace using the same.SOLUTION: A non-ferrous metal melting furnace 1 includes: a melting chamber 2 with an upper end sealed with a lid 7, in which a fed material is melted; a molten metal discharge chamber 3 to which molten metal is fed from the melting chamber 2 and which supplies the molten metal to a casting device for casting; and a molten metal surface level detector 4 for detecting the molten metal surface level in the discharge chamber 3. The non-ferrous metal melting furnace in which an upper limit level L of the molten metal surface of the discharge chamber 3 is higher than a lower surface 7a of the lid 7 of the melting chamber 2 is used for controlling the timing of feeding material into the melting chamber 2. Accordingly, materials are continuously fed until the molten metal surface reaches the upper limit level L. When the molten metal surface reaches the upper limit level L, feeding of materials is stopped, and when the molten metal surface drops below the upper limit level L, feeding of materials is resumed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control method for charging a material to be melted in a melting furnace for melting non-ferrous metals such as aluminum and aluminum alloys for casting, and a non-ferrous metal melting furnace using such a control method.

Background Art

[0002] Conventionally, for example, a melting furnace for melting non-ferrous metals such as aluminum and aluminum alloys to produce cast products such as automotive parts has been widely used. Further, in such a non-ferrous metal melting furnace, in order to prevent the molten metal from oxidizing in a melting chamber (the upper end of which is sealed by a lid) where the charged material is melted by a heater, the level of the molten metal surface in a pumping chamber (hot water discharging chamber) from which the molten metal is supplied is maintained at a position higher than the lower surface of the lid of the melting chamber (see, for example, Patent Document 1).

[0003] Specifically, the non-ferrous metal melting furnace described in Patent Document 1 is provided with a level sensor for detecting the level of the molten metal surface in the pumping chamber, and the upper limit level and the lower limit level of the molten metal surface in the pumping chamber are set higher than the lower surface of the lid of the melting chamber. Then, when the level sensor detects that the molten metal surface has reached the lower limit level, the material is charged, and when it is detected that the molten metal surface has reached the upper limit level, the charging of the material is stopped. By doing so, a space is not formed between the melting chamber and the lid, and oxidation of the molten metal in the melting chamber is prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the melting furnace described in Patent Document 1, since the lower limit level is set below the upper limit level, the lower limit level is likely to be close to the height of the lower surface of the lid (that is, likely to be at almost the same level). Therefore, when the level sensor detects the lower limit level, there is a possibility that the molten metal surface is actually below the lower limit level. As a result, there is a risk of a gap being generated between the molten metal in the melting chamber and the lower surface of the lid, leading to oxidation of the molten metal.

[0006] In addition, since the melting furnace described in Patent Document 1 needs to detect a plurality of molten metal surface levels (upper limit level and lower limit level), for example, compared with a device that detects one molten metal surface level, errors are more likely to occur inevitably. In particular, since the molten metal surface in the ladle chamber fluctuates up and down when the molten metal for casting is withdrawn from there, there is concern about the occurrence of such errors. As a result, a gap is generated between the molten metal and the lower surface of the lid in the melting chamber, and the molten metal will be oxidized.

[0007] Therefore, an object of the present invention is to provide a control method capable of reliably preventing oxidation of molten metal by controlling the input of materials by detecting one molten metal surface level in such a non-ferrous metal melting furnace, and a non-ferrous metal melting furnace using such a control method.

Means for Solving the Problems

[0008] In order to achieve the above object, the material input control method of the non-ferrous metal melting furnace of the present invention has a melting chamber (2) whose upper end is covered by a lid body (7) and melts the input material, and a molten metal is sent from the melting chamber (2) and supplied to a casting apparatus for casting. It has a molten metal surface level detection device (4) for detecting the level of the molten metal surface (F) in the tapping chamber (3), and in a non-ferrous metal melting furnace (1) in which the upper limit level (L) of the molten metal surface (F) in the tapping chamber (3) is higher than the lower surface (7a) of the lid body (7) of the melting chamber (2), it is a method for controlling the timing of inputting materials into the melting chamber (2), Continue to feed the material until the molten metal surface (F) reaches the upper limit level (L). When the molten metal surface (F) reaches the upper limit level (L), stop feeding the material. When the molten metal surface (F) drops below the upper limit level (L), resume feeding the material.

[0009] Moreover, the material feeding control method of the non-ferrous metal melting furnace of the present invention is such that the weight of the material fed at one time is less than the weight of one casting in the casting device, and a predetermined number of materials are fed at a predetermined cycle time for one casting.

[0010] Also, in the material feeding control method of the non-ferrous metal melting furnace of the present invention, when the molten metal surface (F) does not reach the upper limit level (L) when the predetermined number of materials are fed, the predetermined cycle time is set shorter.

[0011] Also, in the material feeding control method of the non-ferrous metal melting furnace of the present invention, before feeding the predetermined number of materials, when the molten metal surface (F) exceeds the upper limit level (L), the predetermined cycle time is maintained or set longer.

[0012] Furthermore, the material feeding control method of the non-ferrous metal melting furnace of the present invention detects the level of the molten metal surface (F) every time the material is fed, and sets the cycle time until the next material feeding corresponding to the amount of change in the level of the molten metal surface (F) in one material feeding.

[0013] Also, in the material feeding control method of the non-ferrous metal melting furnace of the present invention, when the amount of change in the level of the molten metal surface (F) in one material feeding is equal to or greater than the first set reference value, the cycle time until the next material feeding is set longer than the current cycle time. When the amount of change in the level is equal to or less than the second set reference value, which is smaller than the first set reference value, the cycle time until the next material feeding is set shorter than the current cycle time.

[0014] The non-ferrous metal melting furnace (1) of the present invention has a melting chamber (2) whose upper end is covered by a lid (7) and melts the charged material, a tapping chamber (3) to which the molten metal is sent from the melting chamber (2) and supplies the molten metal to a casting device for casting, is provided with a molten metal surface level detection device (4) for detecting the level of the molten metal surface (F) in the tapping chamber (3), and the upper limit level (L) of the molten metal surface (F) in the tapping chamber (3) is set higher than the lower surface (7a) of the lid (7) of the melting chamber (2), the weight of the material charged once is less than the weight of one casting in the casting device, is provided with a control unit (5) for controlling the timing of charging the material into the melting chamber (2), the control unit (5) causes a predetermined number of materials to be charged at a predetermined cycle time for one casting, and when the molten metal surface (F) has not reached the upper limit level (L) when the predetermined number of materials are charged, the predetermined cycle time is set shorter, which is characterized in that.

[0015] Further, in the non-ferrous metal melting furnace (1) of the present invention, when the molten metal surface (F) exceeds the upper limit level (L) before the control unit (5) charges the predetermined number of materials, the predetermined cycle time is maintained or set longer, which is characterized in that.

[0016] Furthermore, the non-ferrous metal melting furnace (1) of the present invention has a melting chamber (2) whose upper end is covered by a lid (7) and melts the charged material, a tapping chamber (3) to which the molten metal is sent from the melting chamber (2) and supplies the molten metal to a casting device for casting, is provided with a molten metal surface level detection device (4) for detecting the level of the molten metal surface (F) in the tapping chamber (3), and the upper limit level (L) of the molten metal surface (F) in the tapping chamber (3) is set higher than the lower surface (7a) of the lid (7) of the melting chamber (2), the weight of the material charged once is less than the weight of one casting in the casting device, is provided with a control unit (5) for controlling the timing of charging the material into the melting chamber (2), The control unit (5) detects the level of the molten metal surface (F) each time a material is charged via the molten metal surface level detection device (4), and sets the cycle time until the next material charge corresponding to the amount of change in the level of the molten metal surface (F) during one material charge.

[0017] Here, the symbols in the parentheses indicate corresponding elements or corresponding matters described in the drawings and the embodiments for carrying out the invention described later.

Effect of the Invention

[0018] According to the material charging control method of the non-ferrous metal melting furnace of the present invention, in a non-ferrous metal melting furnace in which the upper limit level of the molten metal surface in the tapping chamber is set higher than the lower surface of the lid of the melting chamber, the material is continuously charged until the molten metal surface reaches the upper limit level, the charging of the material is stopped when the molten metal surface reaches the upper limit level, and the charging of the material is resumed when the molten metal surface drops below the upper limit level. Therefore, oxidation of the molten metal can be more reliably prevented. That is, in the material charging control method of the present invention, since only the upper limit level is detected to detect the timing of charging the material, there is no possibility of forming a gap between the molten metal and the lower surface of the lid in the melting chamber. This is because the upper limit level can be set sufficiently higher than the lower surface of the lid. Therefore, oxidation of the molten metal can be reliably prevented.

[0019] Also, since only one molten metal surface level (upper limit level) is detected and controlled, for example, errors are less likely to occur compared to the case where a plurality of molten metal surface levels are detected and controlled. Therefore, it is possible to prevent a gap from occurring between the molten metal and the lid, and reliably prevent oxidation of the molten metal.

[0020] In addition, according to the material charging control method of the present invention, since the weight of one charge of the material is made less than the weight of one casting in the casting device, in an extreme example, it is possible to prevent a situation where the molten metal surface greatly exceeds the upper limit level due to the material charged once after one casting.

[0021] Moreover, according to the material input control method of the present invention, when a predetermined number of materials are input and the molten metal surface has not reached the upper limit level, the predetermined cycle time is set shorter, so that a certain amount of molten metal can be stored in the tapping chamber within a certain time. Thereby, the work efficiency can be improved. Also, for each casting, it is always possible to input a predetermined number of materials set in advance or a number close to it, so that the work efficiency can be improved in material management and the like.

[0022] Moreover, according to the material input control method of the present invention, before inputting a predetermined number of materials, when the molten metal surface exceeds the upper limit level, the predetermined cycle time is maintained or set longer. Thus, similar to the above control method, a certain amount of molten metal can be stored in the tapping chamber within a certain time, and for each casting, it is always possible to input a predetermined number of materials set in advance or a number close to it. Therefore, the work efficiency can be improved.

[0023] Furthermore, the material input control method of the present invention detects the level of the molten metal surface for each material input, and sets the cycle time until the next material input corresponding to the change amount of the molten metal surface level in one material input. Thus, similar to the above, a certain amount of molten metal can be stored in the tapping chamber within a certain time, and for each casting, it is possible to input a predetermined number of materials set in advance or a number close to it. Therefore, the work efficiency can be improved.

[0024] Furthermore, in the material input control method of the present invention, when the level change amount of the molten metal surface in one material input is equal to or greater than the first set reference value, the cycle time until the next material input is set to be longer than the current cycle time. When the level change amount is equal to or less than the second set reference value, which is smaller than the first set reference value, the cycle time until the next material input is set to be shorter than the current cycle time. Similarly, a certain amount of molten metal can be stored in the tapping chamber within a certain time, and for one casting, a predetermined number of materials or a number close to it can be input in advance. As a result, the work can be carried out efficiently.

[0025] Also, in the material input control method of the present invention, since the cycle time is set according to the level change amount of the molten metal surface in one material input, for example, even when there is a large difference in the weight of the input materials, the corresponding cycle time can be set immediately.

[0026] According to the non-ferrous metal melting furnace of the present invention, it is provided with a control unit for controlling the timing of inputting materials into the melting chamber. This control unit inputs a predetermined number of materials at a predetermined cycle time for one casting. When the molten metal surface does not reach the upper limit level when the predetermined number of materials is input, the predetermined cycle time is set shorter, so that a certain amount of molten metal can be stored in the tapping chamber within a certain time. Also, for one casting, a predetermined number of materials or a number close to it can always be input in advance. Therefore, the work efficiency can be improved.

[0027] Also, according to the non-ferrous metal melting furnace of the present invention, when the molten metal surface exceeds the upper limit level before the control unit inputs a predetermined number of materials, the predetermined cycle time is maintained or set longer. Similarly, a certain amount of molten metal can be stored in the tapping chamber within a certain time, and for one casting, a predetermined number of materials or a number close to it can be input in advance, and the work efficiency can be improved.

[0028] Furthermore, according to the non-ferrous metal melting furnace of the present invention, it is provided with a control unit for controlling the timing of charging materials into the melting chamber. This control unit detects the level of the molten metal surface every time materials are charged through a molten metal surface level detection device, and sets the cycle time until the next material charging corresponding to the change amount of the molten metal surface level during one material charging. Similarly, a certain amount of molten metal can be stored in the tapping chamber for a certain period of time, and for one casting, it is always possible to charge a predetermined number or a number close thereto of materials in advance. Thereby, the work efficiency can be improved.

[0029] Also, since the cycle time is set according to the change amount of the molten metal surface level during one material charging, even if there is a large difference in the weight of the materials to be charged, a corresponding cycle time can be set.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0031] Hereinafter, a method for controlling the charging of materials in a non-ferrous metal melting furnace according to an embodiment of the present invention will be described when it is implemented using the non-ferrous metal melting furnace 1 according to an embodiment of the present invention for carrying it out.

[0032] The non-ferrous metal melting furnace 1 for implementing the method for controlling the charging of materials according to the present embodiment is used for melting non-ferrous metals such as aluminum and aluminum alloys to manufacture all kinds of casting products such as automotive parts and home appliances. As shown in FIG. 1, it includes a melting chamber 2, a tapping chamber 3, a molten metal surface level detection device 4, a control unit 5, and a material charging device 6.

[0033] The melting chamber 2 is covered such that its upper end is sealed by the lid body 7 (it can also be generally covered), and the charged material is melted by the heating part 8a of the heater 8 in which the heating part 8a provided on the lower side and the electrode part 8b provided on the upper side are connected. The hot water outlet chamber 3 is arranged adjacent to the melting chamber 2, and a communication passage (not shown) through which the molten metal can freely communicate is provided between the two. In the hot water outlet chamber 3, the molten metal from the melting chamber 2 is sent through the communication passage and supplied to a casting device (not shown) for casting.

[0034] Note that a cover part 9 is provided at the upper end of the hot water outlet chamber 3, and an opening 9a is formed in this cover part 9. The molten metal surface level detection device 4 is provided above the hot water outlet chamber 3 and detects the level of the molten metal surface F in the hot water outlet chamber 3 through the opening 9a of the cover part 9. The molten metal surface level detection device 4 detects with continuous values or discrete values at intervals that are not problematic for control. The control unit 5 is provided outside the melting chamber 2 and the hot water outlet chamber 3, receives the signal from the molten metal surface level detection device 4, and controls the timing of charging the material into the melting chamber 2. Also, the temperature of the heater 8 is controlled. The control unit 5 is equipped with a storage part such as a ROM and a RAM in addition to a CPU that controls the whole.

[0035] The material charging control method according to this embodiment implemented using the non-ferrous metal melting furnace 1 basically continues to charge the material until the molten metal surface F reaches the upper limit level L, stops charging the material when the molten metal surface F reaches the upper limit level L, and resumes charging the material when the molten metal surface F drops below the upper limit level L. Also, when a predetermined number of materials are charged, if the molten metal surface F has not reached the upper limit level L, a predetermined cycle time is set shorter, and if the molten metal surface F exceeds the upper limit level L at that time, the predetermined cycle time is maintained or set longer.

[0036] Hereinafter, the material charging control method of the non-ferrous metal melting furnace according to this embodiment will be specifically described. First, set the upper limit level L of the molten metal surface F in the tapping chamber 3 (see Fig. 1). This upper limit level L is set at a position sufficiently higher than the lower surface 7a of the lid 7 of the melting chamber 2 (for example, the molten metal surface F at the upper limit level L is at a height such that it does not fall below the upper limit level L during one tapping). This is to prevent the molten metal from being oxidized by the air accumulating in the space formed between the molten metal in the melting chamber 2 and the lower surface 7a of the lid 7. Also, the weight of one charge of the material is set to be less than the weight of one casting in the casting apparatus. This is, for example, to prevent a situation where after one casting is completed, the molten metal surface F exceeds the upper limit level L and leaks out from the upper end of the tapping chamber 3 due to the material charged at one time.

[0037] Next, corresponding to the weight of the product to be cast in one casting, set the weight of one material (ingot), the predetermined number of materials to be charged for one casting, and the predetermined cycle time for charging these materials one by one. Charging the materials one by one at the predetermined cycle time is to prevent a rapid temperature drop of the molten metal.

[0038] In this embodiment, the weight of one material is set to 5 kg, the predetermined number of materials is set to 6, and the predetermined cycle time is set to 16.36 seconds. It is assumed that the molten metal surface F reaches the upper limit level L or exceeds the upper limit level L after the sixth material is charged. That is, it is a setting to supply the molten metal required for one casting from the tapping chamber 3 to the casting chamber by charging 6 materials of 5 kg each at intervals of 16.36 seconds.

[0039] Note that this predetermined cycle time (16.36 seconds) is the theoretical cycle time Tm (seconds) for material charging, and it is obtained from Tm = Wm / Gss. Wm is the weight of one material (here, 5 kg), Gss is the casting machine casting weight per unit time (here, 0.305556 (kg / sec)), and the predetermined cycle time (16.36 seconds) is calculated from 5 ÷ 0.305556 = 13.363612···. In addition to the predetermined cycle time, the minimum cycle time (13.00 seconds), which is the lower limit value of the cycle time, is calculated from the heating-up capacity of the non-ferrous metal melting furnace. If the cycle time is lower than the minimum cycle time, it becomes difficult for the non-ferrous metal melting furnace to function. Note that instead of setting the number of materials required for one casting to a positive number such as 6, it may be calculated by calculation. As the calculation, for example, a real number such as the value obtained by dividing the casting weight Gss per unit time of the casting machine by the average casting cycle time (for example, 90 seconds) by the weight Wm (5 kg) of one material (about 5.5) can be used.

[0040] Here, for example, if all the materials to be charged are 5 kg and the casting device and the like always operate normally, casting can be performed while maintaining this predetermined cycle time (16.36 seconds) as it is. However, there are usually errors in the weight of each material (for example, 4 to 6 kg), and there are also cases where casting is delayed due to malfunctions of the casting device. In such cases, if the predetermined cycle time is not reset, it may not be possible to store a certain amount of molten metal in the tapping chamber for a certain period of time, and the amount and temperature of the molten metal may deviate from the set values, resulting in a situation where good casting cannot be performed. The material charging control method according to the present embodiment mainly takes these situations into consideration.

[0041] Hereinafter, with reference to FIG. 2, as an example, a control method in the case of performing three casting shots (the first casting shot S1, the second casting shot S2, and the third casting shot S3) will be described. Although it is assumed that each casting shot is performed at 90-second intervals, it varies depending on the weight of the material and the like.

[0042] The first first casting shot is performed as originally set. That is, a material of 5 kg per piece is charged at a predetermined cycle time (the first predetermined cycle time) of 16.36 seconds. Therefore, after the sixth material is charged, since the molten metal surface F reaches or exceeds the upper limit level L, a predetermined amount of molten metal is sent from the tapping chamber 3 to the casting apparatus. Here, the detection of the upper limit level L is performed by the molten metal surface level detection device 4, and the detection signal is sent to the control unit 5. According to the instruction from the control unit 5, the molten metal is tapped.

[0043] The second casting shot S2 following the first casting shot S1 is performed as follows. First, the molten metal in the tapping chamber 3 reduced by the first casting shot S1 is replenished by charging a predetermined number (6 pieces) of materials at the same first predetermined cycle time (16.36 seconds) until the molten metal surface F reaches the upper limit level L. Here, assuming that the weight of one material is 5 kg as described above, when the sixth material is charged, the molten metal surface F reaches or exceeds the upper limit level L, and thus the second casting shot S2 is performed accordingly.

[0044] However, as described above, there is an error in the weight of the materials. Here, it is assumed that the weight of each material to be charged is 4 kg. In this case, if these materials are charged at the first predetermined cycle time (16.36 seconds), the molten metal surface F will not reach the upper limit level L even after the sixth material is charged (because the weight of each material is lighter than in the previous case).

[0045] Therefore, the first predetermined cycle time (16.36 seconds) is reset to a new predetermined cycle time shorter than that. For this purpose, it is conceivable to set it to the minimum cycle time (13.00 seconds) calculated in advance from the heating capacity. However, if the minimum cycle time is set as it is here, the temperature change of the molten metal becomes too drastic, which is not preferable. Therefore, a new predetermined cycle time (the second predetermined cycle time) (14.68 seconds) is set as the average of the two (i.e., according to the calculation formula of (16.36 + 13.00) / 2). It should be noted that it is also possible to set it to the minimum cycle time (13.00 seconds).

[0046] Under the second predetermined cycle time (14.68 seconds) set in this way, one additional new material (with a weight of 4 kg) is added and charged. Therefore, a total of 7 materials (all 4 kg here) will be charged to perform the second casting shot S2. When the molten metal surface F reaches or exceeds the upper limit level L, it is detected and the second casting shot S2 is performed.

[0047] The subsequent third casting shot S3 is also performed in the same way. Assume that the weight of each material is 5.5 kg in this third casting shot S3. Here, since the weight of each material is large, the molten metal surface F reaches or exceeds the upper limit level L when the fifth material is charged. Therefore, the third casting shot S3 is executed after charging 5 materials.

[0048] Note that it is also necessary to set a new predetermined cycle time (the third predetermined cycle time) here. The third predetermined cycle time is set longer than the second predetermined cycle time (14.68 seconds) (or it is also possible to maintain it) because the molten metal surface F reaches or exceeds the upper limit level L when 5 materials are charged in the second casting shot S2.

[0049] The setting of this third predetermined cycle time is 14.68 + α seconds, which is longer than the second predetermined cycle time (14.68 seconds). Various considerations are possible, such as the method of returning to the predetermined cycle time (16.36 seconds) or setting it to a time slightly shorter than the predetermined cycle time (16.36 seconds).

[0050] Also, there may be cases where the casting is delayed due to malfunctions of the casting device. For example, when charging materials at the predetermined cycle time (16.36 seconds), if the casting is delayed due to a malfunction in the stage before charging the third one and waiting until the molten metal surface F reaches the upper limit level L, and as a result, it becomes 18 seconds, for example, the average value until 6 materials are charged (16.63 seconds = (16.36 seconds × 5 materials + 18 seconds) ÷ 6 materials) can be calculated and this value can be determined as the next cycle time.

[0051] Thus, since the material input control method for the non-ferrous metal melting furnace according to this embodiment detects only the upper limit level L to detect the timing of material input, it is possible to prevent a gap from being formed between the molten metal and the lower surface 7a of the lid body 7 in the melting chamber 2. Therefore, oxidation of the molten metal can be surely prevented.

[0052] Also, for example, even if there is an error in the weight of the material to be input, a predetermined cycle time is set accordingly, so that a certain amount of molten metal can be stored in the tapping chamber in a certain time. Therefore, the work can be carried out efficiently. Also, by setting the predetermined cycle time, it is always possible to input a predetermined number of materials set in advance or a number close to it. Therefore, the efficiency of operations such as material management can be improved.

[0053] In the material input control method according to the above embodiment, the case where materials of the same weight are continuously input in one casting shot is shown, but the case where materials of different weights are input successively is also conceivable. In that case, the material input control method according to the above embodiment can handle it, but different material input control methods can also handle it.

[0054] In a different material input control method, using the non-ferrous metal melting furnace 1 according to this embodiment, the level of the molten metal surface F is detected by the molten metal surface level detection device 4 every time a material is input, and corresponding to the change amount of the level of the molten metal surface F in one material input, the cycle time until the next material input is set.

[0055] More specifically, when the level change amount of the molten metal surface F in one material input reaches or exceeds the first set reference value, the cycle time until the next material input is set to be longer than the current cycle time. Also, when the level change amount is equal to or less than the second set reference value, which is smaller than the first set reference value, the cycle time until the next material input is set to be shorter than the current cycle time. That is, the level change amount of the molten metal surface F is maintained between the first set reference value and the second set reference value. By doing so, it is possible to respond well even when materials of different weights are successively input.

[0056] As a result, the upper limit level L of the molten metal surface F can be accurately detected and the casting shot can be performed, so that oxidation of the molten metal in the melting chamber 2 can be prevented. Also, even if there is an error in the weight of the material to be input, a predetermined cycle time is set accordingly, so that a certain amount of molten metal can be stored in the tapping chamber in a certain time, and it is always possible to input a predetermined number or a number close to it of materials. Therefore, the work efficiency can be improved.

[0057] Also, the materials input at one time do not have to be input one by one, but even if a plurality of materials are input by a vibration mechanism or the like, this control method is still valid.

[0058] Note that, like the material input control method according to the above-described embodiment, a method of controlling the input of materials based on the upper limit level L of the molten metal surface F in the tapping chamber 3 and a non-ferrous metal melting furnace 1 using such a control method are not described at all in the above-mentioned patent documents.

Explanation of Reference Numerals

[0059] 1 Non-ferrous metal melting furnace 2 Melting chamber 3 Tapping chamber 4 Molten metal surface level detection device 5 Control unit 6 Material input device 7 Cover 7a Lower surface of the cover 8 Heater 8a Heating part 8b Electrode part 9 Cover part 9a Opening F Molten metal surface L Upper limit level S1 First casting shot S2 Second casting shot S3 Third casting shot

Claims

1. A non-ferrous metal melting furnace having a melting chamber whose upper end is covered with a lid and that melts the charged material, a tapping chamber to which the molten metal is sent from the melting chamber and that supplies the molten metal to a casting apparatus for casting, and a molten metal level detection device that detects the level of the molten metal surface in the tapping chamber, wherein the upper limit level of the molten metal surface in the tapping chamber is set higher than the lower surface of the lid of the melting chamber. A method for controlling the timing of charging material into the melting chamber, comprising: continuing to charge the material until the molten metal surface reaches the upper limit level, stopping the charging of the material when the molten metal surface reaches the upper limit level, and resuming the charging of the material when the molten metal surface drops below the upper limit level. A method for controlling the charging of material into a non-ferrous metal melting furnace, characterized by the above.

2. The weight of the material charged at one time is less than the weight of one casting in the casting apparatus, and a predetermined number of materials are charged at a predetermined cycle time for each casting. The method for controlling the charging of material into a non-ferrous metal melting furnace according to claim 1, characterized by the above.

3. When the molten metal surface does not reach the upper limit level when the predetermined number of materials are charged, the predetermined cycle time is set shorter. The method for controlling the charging of material into a non-ferrous metal melting furnace according to claim 2, characterized by the above.

4. Before charging the predetermined number of materials, when the molten metal surface exceeds the upper limit level, the predetermined cycle time is maintained or set longer. The method for controlling the charging of material into a non-ferrous metal melting furnace according to claim 2, characterized by the above.

5. The level of the molten metal surface is detected each time the material is charged, and the cycle time until the next material charge is set corresponding to the amount of change in the level of the molten metal surface in one material charge. The method for controlling the charging of material into a non-ferrous metal melting furnace according to claim 2, characterized by the above.

6. When the amount of change in the level of the molten metal surface in one material charge is equal to or greater than a first set reference value, the cycle time until the next material charge is set longer than the current cycle time, and when the amount of change is equal to or less than a second set reference value that is smaller than the first set reference value, the cycle time until the next material charge is set shorter than the current cycle time. The method for controlling the charging of material into a non-ferrous metal melting furnace according to claim 5, characterized by the above.

7. A melting chamber whose upper end is covered with a lid and that melts the charged material, a tapping chamber to which the molten metal is sent from the melting chamber and that supplies the molten metal to a casting apparatus for casting, It is provided with a molten metal level detection device for detecting the level of the molten metal surface in the tapping chamber, and the upper limit level of the molten metal surface in the tapping chamber is set higher than the lower surface of the lid of the melting chamber. A non-ferrous metal melting furnace in which the weight of a single charge of material is less than the weight of a single casting in the casting device. It is provided with a control unit for controlling the timing of charging the material into the melting chamber. The control unit causes a predetermined number of materials to be charged at a predetermined cycle time for a single casting. When the molten metal surface has not reached the upper limit level when the predetermined number of materials have been charged, the predetermined cycle time is set shorter. The non-ferrous metal melting furnace is characterized by this.

8. Before charging the predetermined number of materials, when the molten metal surface exceeds the upper limit level, the control unit maintains or sets the predetermined cycle time longer. The non-ferrous metal melting furnace according to claim 7 is characterized by this.

9. A melting chamber with an upper end covered by a lid for melting the charged material. A tapping chamber to which molten metal is sent from the melting chamber and which supplies the molten metal to a casting device for casting. It is provided with a molten metal level detection device for detecting the level of the molten metal surface in the tapping chamber, and the upper limit level of the molten metal surface in the tapping chamber is set higher than the lower surface of the lid of the melting chamber. A non-ferrous metal melting furnace in which the weight of a single charge of material is less than the weight of a single casting in the casting device. It is provided with a control unit for controlling the timing of charging the material into the melting chamber. The control unit detects the level of the molten metal surface each time a material is charged via the molten metal level detection device, and sets the cycle time until the next material charge corresponding to the amount of change in the level of the molten metal surface during a single material charge. The non-ferrous metal melting furnace is characterized by this.

Images