JPH02219978A - Method and apparatus for controlling electromagnetic agitating force applied to melt of aluminum metal chip melting furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a molten metal that is installed in a melting furnace used for remelting aluminum or aluminum alloy cutting waste (commonly known as shavings) to form leakage metal. The present invention relates to a method and device for controlling the thrust force applied to molten metal by a stirring device (hereinafter referred to as a cooler).

More specifically, aluminum or aluminum alloy chips are cut with machine tools such as lathes and are elongated and thin, have an extremely large surface area per unit jl11, and are easily oxidized, resulting in low melting efficiency (JISH2119 calls them "cutting"). It has a vortex generation chamber that generates a vortex in order to melt the cutting material (also called "chips") with high melting efficiency and make high quality molten metal, and by raising the liquid level of this vortex generation chamber. It is applied to reverberatory furnaces that use a cooler to promote the generation of vortices, and the depth of the molten metal in the vortex generation chamber is detected, and the thrust is controlled according to the depth, while maintaining a nearly constant amount of melt. The present invention relates to a thrust control method and device that enables melting.

[Conventional technology]

A low-frequency induction melting furnace, a reflective melting furnace, a reverberatory furnace using an electromagnetic gutter, etc. are used to remelt aluminum or aluminum alloy cutting waste (commonly known as molten powder) into molten metal.

Aluminum is a typical light metal) [As shown in J], its ratio is extremely light with a ratio of approximately 2.7, its melting point is low at approximately 660'C, and its bonding strength with oxygen is strong and it is easily melted. Oxidize.

In addition, general metal materials, including aluminum, have a certain degree of viscosity and toughness, so even if they are cut, the cutting chips will not be in a short (divided) state, but will be in a spiral-like elongated (and thin ribbon state). Become.

Therefore, aluminum-based metal cuttings called briquettes are supplied in a state where the specific volume per unit weight is extremely large and there are many voids, and moreover, it has almost all of the adverse conditions for melting, such as being easily oxidized, and the surface remains unchanged even at room temperature. covered with an oxide film,
In addition, the surface is covered with a fairly thick oxide film because it is usually subjected to preliminary treatments such as degreasing and drying to separate cutting oil and other foreign matter adhering to the surface.

Therefore, when aluminum-based metal chips are charged into a melting furnace heated to a high temperature, they rapidly oxidize and become combustible, resulting in a significant drop in product yield.

In order to melt such aluminum-based metal cutting waste, the cutting waste is charged into the already formed molten metal called the base metal within a short period of time, and the molten metal is heated while avoiding contact with oxygen in the air as much as possible. It is necessary to

On the other hand, even if the inside of somewhat thick cutting chips melts, oxidation progresses while the oxidized skin on the outside prevents the melted part from flowing out, resulting in a very small amount being recovered as molten metal. become.

As described above, depending on the type of melting furnace, melting of aluminum-based metal cutting waste may be extremely difficult, and special care must be taken when melting in a reverberatory furnace where flame is directly blown from the burner.

In the following, we will briefly discuss these difficulties in dialysis with regard to the various furnaces currently in use.

fi+ Crucible melting furnace The melting yield is good, but the power cost is high because it is a batch type and has a small capacity.

(2) Since the iron pot with a stirring device is small and has a small capacity, it requires manual labor and has a low melting yield and high fuel consumption.

(3) A loaf stirrer is a type in which cuttings are continuously fed from the upper part of the mouth, but due to oxidation, the yield is poor, the melting capacity is limited, and the ceramic rotor is subject to significant wear and tear.

(4) Reverberatory Furnace In a normal closed-type reverberatory furnace, when melted with a burner, the temperature of the cuttings rises rapidly and burns, and if the surface is covered with thick oxide, the surface may melt even if the inside melts. There is a lot of dissolution loss due to oxidation.

Therefore, when putting in cutting waste, stop the burner,
The batch method, which involves putting cutting waste into the already molten metal and mixing it using a forklift, will be used for the next summer.

In a reverberatory furnace with an open well, cuttings are fed into the open well, and a pushing plate is used from above to push the slightly bulky cuttings into the molten metal in the open well and melt them, but the melting yield is low and the pushing plate wears out. is fast.

(5) Reverberatory furnace melting device using a molten metal pump In order to deal with the various problems mentioned above, the fifth
A melting furnace as shown in Figure (Al.fBl) has been proposed and is in use in some cases.

To give an overview of this charging, a vortex chamber 1113 is arranged below the chip conveyor 62 on the charging port 61 side of the reverberatory furnace 60,
A molten metal suction port 64 is provided at the lower end of this vortex chamber 63, and a mechanical molten metal pump 66 is arranged at the charging port 61 of the furnace body and the opposite side 65 thereof. I-channel shaped molten metal passage 67 extending almost horizontally
It is connected by .

When the raw metal is charged into this reverberatory furnace and the molten metal pump 66 is operated, the molten metal in the vortex chamber 63 is sucked and rapidly passes through the suction port, and a vortex is generated above the molten metal.

When the cutting chips are thrown into the vortex by the chip conveyor 62, the chips are drawn into the vortex of the molten metal, are rapidly dissolved in the molten metal, and are sent to the heating chamber from the discharge port of the molten metal pump 66.
It flows into the vortex chamber 63 again and circulates.

In this way, the problem of preventing aluminum-based metal chips from being worn out by oxidation and rapidly dissolving them is achieved to some extent.

However, in the above-mentioned reverberatory furnace, which is based on the premise of using a molten metal pump, two problems occur during actual operation, which can be broadly classified as follows.

(Due to the necessity of using the reconnaissance molten metal pump, there is a tunnel-shaped molten metal passage arranged horizontally and fluid-tight between the molten metal suction port 64 at the lower end of the vortex v63 and the molten metal pump suction Must be connected through a tunnel.

This molten metal pump is designed to raise the molten metal temperature (700°
C or more) and that the welding depth of the pump insertion part be large (250+am or more) due to the structure, and it is necessary to satisfy these conditions first before use.

If the furnace suddenly stops operating due to some cIR cause, the molten metal in the furnace will remain in the molten metal tunnel at the bottom of the furnace, and the molten metal will cool down by melting cuttings and will not solidify. There is a simple drawback.

Furthermore, once the molten metal solidifies in the molten metal tunnel, it cannot be restarted unless it is melted by some means or removed mechanically, which requires idle running time and man-hours for removal. The cost will be considerably high.

(rl) Due to its structure, mechanical molten metal pumps have operating parts such as blades that come into direct contact with molten aluminum containing dross-stopping foreign matter.

The blades and other parts of the molten metal pump are made of silicon nitride (SiN).
) and silicon carbide (SiC1), but they rotate at a considerable speed in contact with corrosive molten aluminum, so they are prone to corrosion and erosion. It is unavoidable that these parts are subject to wear and tear due to the cost of these parts themselves, losses due to body movements,
This results in an increase in costs due to the number of man-hours required to replace parts.

fBl tea Mechanical melting furnace that promotes vortex generation in the vortex generation section using an agitator? f! In order to solve the above-mentioned problems caused by the use of a dry pump, the prior invention by the applicant of the present application uses an electromagnetic stirrer (hereinafter referred to as "starcoo") instead of a molten metal pump.
The first MiJ recommendation is to adopt a mechanical molten metal pump, and by rationally setting the structure, arrangement, and dimensional relationship of the related parts shown below to correspond to this front embankment, we will install a mechanical molten metal pump. In addition to solving the above-mentioned problems of the adopted reverberatory furnace, we also tried to achieve functions and advantages that cannot be achieved by molten metal water pumps with respect to other issues.

(B) Structure of the entire furnace body In the following explanation, the direction from the cutting waste charging inlet of the reverberatory furnace to the opposite side is referred to as the longitudinal direction of the furnace. Now, on the bottom side, there is a starcoo, a vortex chamber,
The passage for the molten metal containing molten metal (and cutting waste) is placed on the opposite side in the longitudinal direction in the plan view, and the upper side in Figures 1 (A) and 3 is a molten N (warming chamber) where the molten metal is heated by a burner and the temperature is increased. )
The two rooms are separated by an intermediate wall that does not reach the ceiling of the furnace.

The molten metal passage is inclined upwardly from the charging port side to the opposite side at a position midway between the vortex chamber and the starch, as shown in FIG. 1 fBl.

This is to raise the level of the molten metal within the vortex generating chamber within an effective range, and is closely related to the structure of the vortex chamber which will be described next.

In addition, the inner periphery of the furnace wall, especially the corner part of the vortex chamber, and the corner part of the furnace wall corresponding to the end of the path for the molten metal flowing down from this chamber, have a circumference with a large radius in cross section. It will be built with a large R.

(01 vortex generation chamber (hereinafter abbreviated as vortex chamber) vortex chamber:
In order to prevent the wear and tear of aluminum-based metals due to oxidation, the amount of cutting chips that come into contact with oxygen in the atmosphere and undergo oxidation must be reduced as much as possible by rapidly rolling the cutting chips into the molten metal in the vortex chamber. The structure is such that it generates a vortex that has sufficient entrainment action to push the melt into the molten metal.

For this purpose, a wall of refractory material that makes the vortex chamber nationally useful in plan view is made to protrude like a jetty toward the front wall of the furnace, and its tip is aligned with the axis of the suction port provided at the bottom of the vortex chamber. or closer to the wall on the charging port side of the furnace body, so that the molten metal flowing into the vortex chamber flows along the inner periphery of the furnace wall.

In addition, the dimensional ratio of the inner diameter of the entire vortex chamber, the inner diameter of the inlet of the suction nozzle at the bottom of the vortex chamber, and the inner diameter of the outlet of the suction nozzle of the vortex chamber was set within a range suitable for vortex generation.

(c) Providing a lid over the molten metal passage On the molten metal passage where the starch is installed, if necessary, provide an i41 to cover the top of the molten metal as shown in FIG. As a result, all the thrust exerted on the molten metal by the starcooler is concentrated in the direction of the molten metal's progress, and the molten metal level in the melting chamber (heating chamber) is lower than the molten metal level in the molten metal passage at the bottom of the lid, that is, the molten metal level. High (high) promotes the generation of vortices in the vortex chamber.

(:) Stark marks are placed above and below the molten metal passage as shown in Figure 4.
In this case, the member supporting the starch 15' above the molten metal passage also acts as the lid mentioned in the previous item (c), and the upper and lower starch and the lid work together to control the thrust applied to the molten metal in the direction of movement of the molten metal. Concentrate on.

(7) Melting furnace that uses an electromagnetic bucket to raise the liquid level of the molten metal. Furnaces that use an electromagnetic bucket instead of the horizontal Stark also raise the molten metal level, increase the depth of the molten metal, and generate vortices in much the same way as the Starke. It can be promoted.

[Problem to be solved by the invention] In an open well type reverberatory furnace, a vortex generation chamber (abbreviated as a vortex chamber) is provided on the blade side in the transverse direction of the open well section, and the bottom of this vortex chamber is connected to the remaining part of the open well section. If the dimensions of the nozzle are appropriately selected, the generation of vortices between the surface of the molten metal in the vortex chamber and the suction nozzle will be promoted. be done.

In a closed reverberatory furnace without an open well, 12
As shown in the figure, a vortex chamber is provided on one side of the dissolution chamber in the transverse direction on the charging port side. In addition to providing a vortex chamber in this way, a portion of the molten metal flow path from the charging port to the opposite side of the vortex chamber is made into a slope that rises in the downstream direction, and the lower side of the horizontal part beyond the slope is made into a star. If the molten metal is forced to flow using a strong tM1 stirring force, the molten metal changes its direction by the front wall and flows toward the charging port, raising the molten metal level (also called liquid level or level) in the vortex chamber. let

In this way, the molten metal liquid level in the vortex chamber is raised in NAI manner by tm induction, and as the molten metal depth changes, the state of vortex generation also changes.5 When the molten metal is shallow, the vortex becomes large and ripples occur in the scene. On the other hand, as the molten metal becomes deeper, if the thrust caused by the magnetic stirring force is left unchanged, the vortex becomes smaller and the melting ability decreases.

In this way, when the amount of molten metal is increased by starting from the site and using scrap, etc., or when a certain amount of metal is tapped, the furnace must be operated from a state where the amount of molten metal in the furnace has decreased. , H! As the depth of the molten metal in the four chambers changes, the molten metal capacity of the scrap also changes, so the operating conditions also change, making the work difficult and unfavorable from the productivity point of view.

Therefore, there was a need to develop a method for melting the metal under quiet melting conditions by keeping the melting ability almost constant regardless of the depth of the molten metal in which the vortices are generated, and the development of a control device necessary for this.

[Means for solving the problem J Starting from the original site, increase the volume of melt in the vortex chamber by 1) 4 ft while inserting aluminum-based metal cuttings, and increase the thrust until a steady operating state is reached. While increasing the molten metal depth, once the specified depth is reached, start cooling to maintain this molten metal depth.

control the thrust of the

The Stark uses electromagnetic induction or the same principle as a near motor, is operated by a 1tm coil and a variable power supply, generates linear thrust, and has a low frequency a of commercial frequency or lower.
A tt source is used and the thrust is increased or decreased by controlling the current and/or frequency by varying it.

To detect the depth of the molten metal, since aluminum dripping water is conductive, one electrode is constantly immersed in the molten metal, and the other electrode is raised and lowered above the liquid surface via a pulley with a built-in volume resistor. The equation electrode is moved up and down, and the rotation angle of this pulley is converted to the molten metal level and set.Meanwhile, the relationship between the molten metal level and the required thrust is experimentally determined and graphed, and the relationship is calculated in response to the detected level. Increase or decrease Stark's thrust.

[Operation] When the source material is introduced into the reactor and the starcoo reaches the lowest level at which it can operate, the lifting electrode is raised stepwise or almost continuously to increase the thrust of the starcoo. After reaching the steady state, the molten metal level is maintained.

When the molten metal level drops due to tapping, etc., a thrust corresponding to the molten metal level is applied to restore the molten metal level, and a predetermined vortex is generated and scrap is thrown in to restore the molten metal level.

In addition, if the relationship between the molten metal depth and time from the start of melting to reaching steady operation is set for a specific furnace body depending on the type of molten metal to be melted, the depth can be set so that the molten metal level reaches 2 over time. A program control method is applied to raise or lower the thrust detector and increase or decrease the thrust accordingly.

[Example] Since the thrust control device of the present invention is a device that controls the thrust of the cooler according to the depth of the molten metal by detecting the level of molten metal in the vortex chamber, the thrust control device of the present invention is installed in the vortex chamber. The configuration and operation of the arranged embodiment will be explained.

Regarding the configuration of the reverberatory furnace itself to which the present invention is applied, as disclosed in the above-mentioned prior invention, the presence or absence of an open well part, the case where the stirrer is placed only below the molten metal passage, or both above and below, or when the stirrer is placed in addition to the stirrer. Various implementations exist, such as capping the molten metal passages, but even though the correlation between the molten metal level in the vortex chamber and the required thrust may be influenced by these factors, they are dependent on the characteristics of the individual furnace body. It is considered to be a fixed constant, and the arrangement and operation of the control device can be explained in almost the same way.

Therefore, in the explanation of the embodiment, only the case where the cooler is placed in the vortex chamber of a reverberatory furnace having an open well part will be illustrated and explained. Explanation will be omitted.

Figure 1 (C1) shows an example in which the control device of the present invention is placed in Uradome of the open well type reverberatory furnace shown in Figure 1 fA) and fil, and C-C line in Figure 1 fA). FIG.

The symbol lO in the figure indicates the entire reverberatory furnace, 12 is the open well part, 13 is the vortex chamber, 13' is the partition wall between the open well part and the vortex chamber, 13'' is the bottom wall of the vortex chamber, and 19'' is the bottom wall, 2
4 is a discharge nozzle.

The molten metal depth detecting device which constitutes the main body of the present invention consists of the immersion electrode 26
The immersed electrode 26 is placed immersed in the molten metal, while the up/down electrode 27 is normally placed above the immersed electrode 26 and above the liquid level of the molten metal. If the molten metal is wound up or unwound by a winding drum with a built-in volume resistor, it becomes possible to quantitatively measure the position of the molten metal surface from changes in the viewing resistance.

By appropriately selecting the diameter of the winding drum and pulley, it is also possible to detect the molten metal level from the rotation angle.

These 111 poles have respective leads 26° and 27
Detector 31 and power supply 32 shown in Figure 1 tc+ through ゜
If there is no molten aluminium-based metal between the immersion electrode 26 and the lifting electrode 27, the circuit is open. When the level of the molten metal rises and comes into contact with the lifting electrode 27, the circuit is closed and current from the power source flows, and the detector 31 indicates that the level of the molten metal has reached the lifting electrode 27.

As a means of indicating, an acoustic signal or an alarm lamp may be used, or both may be used in combination.

An operation for melting aluminum-based metal cutting waste using the apparatus of the present invention will be described.

A thrust force is applied to the molten metal by a cooler to generate a vortex in the molten metal in the vortex chamber, and aluminum-based metal cuttings are charged into the vortex part. It must be at the lowest position of the symbol f shown in Figure 1 (IB), which is the easiest level.

This also applies to the Al molten metal passage 11 in Figure 1, and unless the molten metal in the molten metal passage 11 reaches the lowest position indicated by symbol f, the stirrer cannot exert sufficient thrust on the molten metal. .

To start melting, first, the molten metal melted in another furnace is used as the base metal and is supplied to the lowest position of symbol f. 2. When the cooler is not operating [511f for molten metal! Since no stirring force is applied, the molten metal in the vortex chamber and in the molten metal passage 11 are at the same level.

It can also be confirmed by the detection means of the present invention whether the source hot water has reached the lowest position indicated by symbol f.

The depth of the molten metal is divided into several stages from the lowest level shown in Figure 1 (B) to the highest level shown by e, and the method is By experimentally setting the frequency and II flow control variables, it is possible to provide the optimum thrust for any level m.

First, it can be confirmed by the detection means of the present invention whether the source field has reached the lowest position of the symbol f.

Next, the elevating and lowering electric power frM27 is raised to the next level, for example, m, and Starcoo is controlled to generate a thrust corresponding to m'+4.

When it is detected that the level of the molten metal in the vortex chamber has increased to m, the lifting electrode 27 is raised to the next level m2, and the current is increased so that the starcooler generates a thrust corresponding to this m8. Control frequency.

Thereafter, the same operation is repeated until the molten metal level rises and reaches the highest level e of the molten metal, and the molten metal in the vortex chamber is
Starku will give you the optimal thrust that is preset according to the level.

In this embodiment, the five lifting electrodes 27 are connected to the next electrode. We have explained a manual stepwise control method in which the thrust is controlled by Starku in response to an arbitrary target level mn', but calculations and repeated experimental results show that Ps The lowest level f may be the highest level e
When a state is reached in which the optimum thrust is continuously indicated, the side-out value of the molten metal level detected by the detector 33 is inputted to the regulator 34 as shown in <01 in Fig. 1, and the control signal from the regulator is inputted. The thrust controller fi! It is also possible to adopt a feedback type automatic control system in which the molten metal in the molten metal flow path is operated with the molten metal 35 to apply an optimum thrust to the molten metal in the molten metal flow path.

[Effects] As described above, the method and device for controlling the electromagnetic stirring force applied to the beach according to the present invention uses a simple detector consisting of an immersion type electrode and an elevating type electrode. Then, the lowest level of the molten metal that should exist as a heaven is detected, and then the 44 elevating poles 27 are raised one after another in multiple stages or continuously up to the target level m+, and the star-coupling is performed in accordance with the target level m7. By using a relatively simple control method that controls the applied thrust, the vortex generated in the molten metal is maintained in a nearly constant state even if the depth of the molten metal in the vortex chamber changes, and the melting of aluminum-based metal cutting chips is achieved. It is possible to control the process to be most efficient and to maintain a constant amount of dissolution in a stable state! This control force type and control device are extremely effective when applied to melting furnaces that melt aluminum scrap.

[Brief explanation of the drawing]

Fig. 1 (A, 1 is an open well type reverberatory furnace to which the present invention is applied, and a vortex generation chamber is installed in one corner of the open well part.
A plan view of a furnace body in which a vortex (N) is provided, tel in the same figure is a side view, and tc+ in the same figure is a cross-sectional view showing a state in which the detection device 1 of the present invention is arranged with a pole in the vortex chamber of the furnace, Same figure (0
) is the same (a block diagram when the automatic control method is applied to the present invention, Fig. 2 is a plan view of a closed reverberatory furnace without an open well section, and Fig. 3 is a plan view of a closed reverberatory furnace without an open well section, and Fig. 3 shows a case where a lid is provided over the molten metal i! path). Fig. 4 is a front sectional view of the furnace body with star coolers installed above and below the molten metal passage, and Fig. 5 is a front sectional view of the furnace body with
A) and (81) are a side sectional view and a plan sectional view of a reverberatory furnace of the prior art in which a vortex chamber is provided in one corner of the furnace body and molten metal is circulated by a molten metal pump.Reference numeral 10 in Drawing I: Furnace of reverberatory furnace Body, 11: Molten metal passage, 12: Melting chamber. 13: Swirl chamber, 13': Partition wall of the vortex chamber, 13": Bottom wall of the vortex chamber 214: Open well part, 15.15' Varnish cooler 16: Molten metal passage Partition wall, 24: Discharge nozzle, 26:
Immersed electrode, 26': Lead wire, 27: Lifting electrode, 27
°: Lead wire, 28; wire 29:1! Scraping drum (pulley 31: detector, 32 = power supply, 33: molten metal level detector, 34: regulator, 35: thrust controller. Agent: Patent attorney Takeo Goto Agent: Patent attorney Haruya Saifuji

Claims (1)

[Claims] 1. A method for controlling a reverberatory furnace type melting furnace that operates by replenishing and melting aluminum-based metal cuttings, wherein When involving and melting aluminum-based metal cuttings, the optimum thrust of the electromagnetic stirrer is set in advance for the liquid level corresponding to the variable depth of the molten metal in the vortex chamber, and the electromagnetic stirrer is operated to adjust the thrust. The liquid level of the molten metal in the vortex chamber is raised above the liquid level of the molten metal in the molten metal passage leading from the lower part of the vortex chamber to the melting chamber to increase the melting ability, and the liquid level of the molten metal in the vortex chamber is raised. A method for controlling electromagnetic stirring force applied to molten metal, the method comprising: detecting the molten metal; and controlling an electromagnetic stirrer so as to apply an optimal thrust to the molten metal at the detected liquid level. 2. The method for controlling the electromagnetic stirring force applied to molten metal according to claim 1, characterized in that the melting furnace is an open-well reverberatory furnace and the vortex chamber is provided in one corner of the open-well portion. A method of controlling the electromagnetic stirring force applied to molten metal. 3. In the method for controlling the electromagnetic stirring force applied to molten metal according to claim 1, the melting furnace is a closed reverberatory furnace,
A method for controlling electromagnetic stirring force applied to molten metal, characterized in that the vortex chamber is provided in one corner of a melting chamber. 4. In the method for controlling the electromagnetic stirring force applied to the molten metal according to claim 1, a lid is provided over the molten metal passage of the melting furnace so that the thrust of the electromagnetic stirrer is concentrated in the direction of the flow of the molten metal. A method of controlling the electromagnetic stirring force applied to molten metal. 5. In the method for controlling the electromagnetic stirring force applied to the molten metal according to claim 1, an electromagnetic stirrer is provided above and below the molten metal passage of the melting furnace, and the thrust of the electromagnetic stirrer is directed in the direction of the flow of the molten metal. A method of controlling the electromagnetic stirring force applied to concentrated molten metal. 6. The method for controlling the electromagnetic stirring force applied to the molten metal according to claim 1, wherein the molten metal passage of the melting furnace rises from slightly in front of the vortex chamber toward the rear wall on the side opposite to the charging port of the furnace. A method of controlling the electromagnetic stirring force applied to the molten metal, which is formed as an electromagnetic gutter along which an electromagnetic stirrer is installed below. 7. As a reverberatory furnace type melting furnace that operates by replenishing and melting aluminum-based metal cuttings, there is a vortex chamber installed on the charging port side of the furnace, and aluminum-based metal cuttings are drawn into the vortex generated within this vortex chamber. In order to increase melting ability, an electromagnetic device is used to apply thrust to the molten metal flowing down from the vortex chamber and raise the liquid level of the molten metal in the vortex chamber above the liquid level of the molten metal in the molten metal passage leading from the lower part of the vortex chamber to the melting chamber. A thrust control device for a melting furnace, comprising: a stirrer; 1. A device for controlling an electromagnetic stirring force applied to molten metal, comprising a control means for controlling the electromagnetic stirrer so as to provide a preset optimum thrust. 8. The device for controlling the electromagnetic stirring force applied to the molten metal according to claim 7, wherein the detector for detecting the liquid level of the molten metal in the vortex chamber includes an immersed electrode that is constantly immersed in the molten metal in the vortex chamber; an elevating electrode capable of moving up and down between the lowest liquid level of the molten metal required for thrust to be applied by the electromagnetic stirrer and the highest liquid level determined by the capacity of the vortex chamber; the molten metal and the elevating electrode; When the electrode changes from non-contact to contact, the circuit closes and the liquid level of the molten metal in that state is read as a change in the rotation angle of the drum connected to the wire that moves the lifting electrode up and down and is indicated as the liquid level of the molten metal. A device for controlling electromagnetic stirring force applied to molten metal, characterized in that it has an indicator. 9. The apparatus for controlling the electromagnetic stirring force applied to the molten metal according to claim 7, wherein the control means for controlling the electromagnetic stirrer is configured to manually stir the molten metal according to the detected liquid level of the molten metal. A device that controls the electromagnetic stirring force applied to the 10. The apparatus for controlling the electromagnetic stirring force applied to the molten metal according to claim 7, wherein the control means supplies the electromagnetic stirring force to the electromagnetic stirrer by a thrust controller in response to a control signal from a regulator responsive to the detected liquid level of the molten metal. A device that controls the electromagnetic stirring force applied to molten metal by automatically controlling the current and frequency.