JP4245673B2 - Aluminum melting furnace with stirring device, molten aluminum stirring device, and molten aluminum stirring method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum melting furnace with a stirrer, a molten aluminum stirrer, and a molten aluminum stirring method, and in particular, an aluminum melting furnace with a stirrer that stirs molten aluminum by a magnetic force generated by a permanent magnet, a molten aluminum stirrer, and The present invention relates to a molten aluminum stirring method.
[0002]
[Prior art]
For example, as a conventional aluminum melting furnace with a stirrer used for remelting recycled aluminum, an electromagnetic coil is closely attached to the outside of the furnace, and a magnetic field is moved by flowing a three-phase current through the electromagnetic coil. There was a so-called linear motor type (electromagnetic coil type). Some linear motor type aluminum melting furnaces have an electromagnetic coil in close contact with the outer periphery of the furnace, and others are attached outside the bottom of the furnace. That is, in such an aluminum melting furnace, the molten aluminum in the furnace is agitated by the magnetic force generated by the eddy current flowing in the aluminum as the magnetic field moves. More specifically, in the case where the electromagnetic coil is closely attached to the outer periphery of the furnace, the magnetic field moves in the circumferential direction, and in the case where the electromagnetic coil is closely attached to the outside of the furnace bottom portion, the magnetic field moves in a direction parallel to the furnace bottom. An eddy current flowed in the molten aluminum in the furnace, and the molten aluminum was stirred by the electromagnetic force accompanying this.
[0003]
As a type different from the electromagnetic coil type described above, mechanical aluminum melting that stirs molten aluminum by directly immersing rotating blades in molten aluminum in the furnace and rotating the rotating blades from the outside. There was also a furnace.
[0004]
[Problems to be solved by the invention]
In the electromagnetic coil type aluminum melting furnace described above, since a magnetic field line has to be passed to the vicinity of the center of the molten aluminum in the furnace, a large current has to be supplied to the electromagnetic coil. For this reason, the heat generated in the electromagnetic coil is remarkably large. For this heat radiation, a hollow copper wire is used as a coil material, and cooling is performed by circulating cooling water in the hollow copper wire. The inner diameter of the cooling water passage of this hollow copper wire is usually as thin as about 4 mm to 6 mm, and is easily clogged with foreign matters such as scale. When the passage of the hollow copper wire is clogged, the cooling of the electromagnetic coil becomes insufficient, and there is a problem that the electromagnetic coil is burned out due to heat generation of the electromagnetic coil. On the other hand, in order to obtain a magnetic force necessary to sufficiently stir molten aluminum, a large current must be passed, power consumption is very large, and running cost is also large. Furthermore, since it is necessary to use a hollow copper wire as the coil material and to provide a cooling water circulation device, the entire aluminum melting furnace has been increased in manufacturing cost.
[0005]
In addition, since the magnetic field in the furnace is moved by supplying a three-phase current to the electromagnetic coil, the stirring speed of the molten aluminum is proportional to the moving speed of the magnetic field. In order to change the stirring speed, it is necessary to change the moving speed of the magnetic field. This change in the moving speed of the magnetic field has been performed by changing the frequency of the three-phase current using an inverter circuit. However, since the electromagnetic coil has inductance, the magnitude of the moving magnetic field is reduced when the frequency is increased. For this reason, the frequency of the current flowing through the electromagnetic coil cannot be increased to 4 Hz or more at present, and the stirring speed of the molten aluminum in the furnace cannot be freely controlled.
[0006]
On the other hand, in a mechanical aluminum melting furnace in which rotating blades are inserted into the furnace, the rotating blades are directly immersed in molten aluminum at about 800 ° C., so that there is a problem that the rotating blades are significantly damaged.
[0007]
Thus, these conventional types had many problems. The present invention pays attention to such problems of the prior art, and by using a permanent magnet instead of the electromagnetic coil as the magnetic field generating means, the manufacturing cost and running cost are low, and the possibility of failure is low. An object of the present invention is to provide an aluminum melting furnace with a stirrer that can freely change the speed.
[0008]
[Means for Solving the Problems]
The aluminum melting furnace with a stirrer according to the present invention includes a furnace main body for storing molten aluminum melted by heating from the outside, and the lower outer end surface of the bottom of the furnace main body, not on the outer periphery of the furnace main body. And a plurality of permanent magnets that generate through magnetic field lines penetrating through the molten aluminum in the furnace body in a substantially vertical direction, and rotating the permanent magnets. Accordingly, the penetration magnetic field lines are configured to move in a state of penetrating the molten aluminum in a substantially vertical direction, thereby applying a moving force to the molten aluminum and stirring in the furnace body, and generating the moving magnetic field. The apparatus includes a bearing provided in a fixed state with respect to the furnace body, and a rotating plate supported by the bearing so as to be rotatable about an axis that runs substantially up and down. A plurality of permanent magnets arranged circumferentially so that different poles are alternately placed on the surface side facing the furnace main body on the net base and the magnet base. It is characterized by that.
Furthermore, the molten aluminum agitator of the present invention faces the lower outer end surface of the bottom of the furnace main body in the vertical direction, not on the outer periphery, but on the outer periphery of the furnace main body that stores the molten aluminum melted by heating from the outside. And a plurality of permanent magnets that generate through magnetic field lines penetrating the molten aluminum in the furnace main body in the vertical direction, and the penetration is performed as the permanent magnets rotate. The magnetic field lines are configured to move in a state of penetrating the molten aluminum in a substantially vertical direction, thereby applying a moving force to the molten aluminum and stirring the molten aluminum in a fixed state with respect to the furnace main body. A provided bearing, a magnet base as a rotating plate rotatably supported about an axis that runs substantially up and down by the bearing, and the magnet base A plurality of the permanent magnets arranged in a circumferential manner so that different poles are alternately arranged on the surface side facing the furnace main body. .
Furthermore, the molten aluminum stirring method of the present invention is a molten aluminum stirring method for stirring molten aluminum in a furnace body in an aluminum melting furnace, wherein the molten aluminum stirring device is not on the outer periphery of the furnace body but on the lower side. The bottom of the furnace body is arranged so as to face the lower outer end surface of the bottom of the furnace body, and as the molten aluminum stirring device, a bearing provided in a fixed state with respect to the furnace body, and an axis that runs substantially up and down by the bearing A magnet base as a rotating plate that is rotatably supported around and a plurality of circumferentially arranged poles on the magnet base so that different poles are alternately placed on the surface facing the furnace body The permanent magnets are made to penetrate the molten aluminum in the furnace body in the vertical direction substantially in the vertical direction, and the plurality of permanent magnets are in this state. By rotating the stone together with the magnet base and rotating the magnetic field lines in a state of penetrating the molten aluminum in a substantially vertical direction, a moving force is applied to the molten aluminum so that the axis of the axis running in the vertical direction in the furnace body It is characterized by stirring around.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Before describing the embodiment of the present invention, the operation principle of the present invention will be described. The present invention intends to stir molten aluminum by a magnetic force generated by moving a magnetic field line from a permanent magnet penetrating the molten aluminum. More specifically, when the permanent magnet 51 is disposed below the aluminum plate 50 in FIG. 5 with the N pole facing up, the magnetic lines of force 52 penetrate the aluminum plate 50 from the bottom to the top. When the permanent magnet 51 is moved to the left side at a speed V as indicated by an arrow in the figure in this state, eddy currents 53A and 53B are generated before and after the permanent magnet 51 of the aluminum plate 50 according to Lenz's law. Magnetic field lines 54 </ b> A and 54 </ b> B are generated along with the eddy current 53, a repulsive force acts between the magnetic field line 54 </ b> A and the magnetic field line 52 by the permanent magnet 51, and an attractive force is generated between the magnetic field line 54 </ b> B and the magnetic field line 52 by the permanent magnet 51. The aluminum plate 50 moves to the left side of the figure at the speed V ′. At this time, the relationship between the speed V and the speed V ′ is speed V> V ′. Considering molten aluminum instead of the aluminum plate 50, since the molten aluminum is also a conductor, the same phenomenon as the aluminum plate 50, that is, the phenomenon that the molten aluminum moves as the permanent magnet 51 moves is caused. .
[0010]
The present invention has been made by the inventor by focusing on this phenomenon.
[0011]
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4.
[0012]
1 is a longitudinal sectional view of the entire apparatus of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1 with the nonmagnetic cover 33 removed, and FIGS. 3 and 4 are side views of the furnace 20. FIG.
[0013]
As can be seen from FIG. 1, the apparatus of the present invention has a heavy oil burner 4 and an aluminum melting furnace 2 with a stirrer that melts the aluminum heated thereby while stirring. Since this burner 4 is well known in this technical field, a detailed description is omitted. In addition to the type in which the aluminum in the furnace body 20 is directly heated as shown in FIG. A type of heating from the outer side wall can also be adopted.
[0014]
The aluminum melting furnace 2 includes a portion that functions as a so-called furnace in the upper half and a portion that magnetically stirs the molten aluminum 22 in the lower half. More specifically, the aluminum melting furnace 2 has a frame 10 made of a substantially cylindrical nonmagnetic material as a so-called chassis extending over the two upper and lower portions. The internal space of the frame 10 is partitioned into an upper space 13 and a lower space 14 by the first partition wall 11. A container-shaped furnace body 20 is housed and disposed in the upper space 13, and a stirring mechanism 30 is disposed in the lower space 14.
[0015]
As can be seen from FIG. 3 and FIG. 4 in particular, the furnace body 20 is integrally formed with protrusions 24 having a substantially triangular cross section on the inner wall every 90 degrees. These ridges 24 are for making the molten aluminum 22 sufficiently stirred by making the flow of the molten aluminum 22 melted and stirred inside the furnace body complicated and irregular. In order to realize this, each protrusion 24 has one of the two side surfaces curved in a concave shape, and the other is substantially planar. The arrows in FIG. 4 show an example of the flow by stirring of the molten aluminum 22. As can be seen from FIG. 1, even if the molten aluminum 22 in the furnace body 20 is about to flow out for some reason, it is received and prevented by the frame 10.
[0016]
In the lower space 14 of the frame 10, as described above, the stirring mechanism 30 for stirring the molten aluminum 22 in the furnace body 20 is provided. The lower space 14 includes a space 14a in which a moving magnetic field generator 40 as a permanent magnet assembly is rotatably accommodated by the second partition wall 12, a motor 43 that rotationally drives the moving magnetic field generator 40, and a bearing described later. 41 is partitioned into a space 14b for storing the space 41b. In order to prevent the magnetic field from leaking to the outside, a magnetic shielding plate 34 is provided on the entire wall of the space 14a.
[0017]
The moving magnetic field generator 40 in the stirring mechanism 30 has a disk-shaped magnet base 31. As shown in FIG. 2, on the magnet base 31, there are provided four permanent magnets 32a to 32d fixed at intervals of 90 degrees and a non-magnetic cover 33 covering these as shown in FIG. . As can be seen from FIG. 2, the permanent magnets 32a to 32d fixed on the magnet base are arranged so that different poles are alternately arranged on the upper surface. As can be seen from FIG. 1, a shaft 42 is attached to the lower side of the magnet base 31. The shaft 42 is supported by the bearing 41 fixed to the second partition wall 12. As a result, the moving magnetic field generator 40 is supported so as to be rotatable with respect to the frame 10. A driven pulley 44 is fixed to the lower end of the shaft 42.
[0018]
In order to drive the driven pulley 44, a motor 43 is attached to the side surface of the bearing 41, as can be seen from FIG. A driving pulley 43 a on one end side of the shaft of the motor 43 is connected to a driven pulley 44 attached to an end portion of the shaft 42 by a belt 45.
[0019]
Next, the operation of the above apparatus will be described.
[0020]
When unmelted aluminum that has been recycled is put into the furnace body 20 and heated by the burner 4, the aluminum melts and becomes molten aluminum 22.
[0021]
At the same time, the moving magnetic field generator 40 is rotated by the motor 43. Due to the rotation of the permanent magnet 32 accompanying this, the magnetic lines of force from the permanent magnet 32 move in a state of penetrating the molten aluminum 22. As a result, a magnetic force acts on the molten aluminum 22, and the molten aluminum 22 is stirred in the furnace body 20. More specifically, regarding the permanent magnets 32a and 32c with the N pole on the top in FIG. 2, the magnetic field lines from these permanent magnets 32a and 32c penetrate the molten aluminum 22 in the furnace body 20 from the bottom to the top. . On the other hand, regarding the permanent magnets 32b and 32d with the south pole on the top, the lines of magnetic force from these permanent magnets 32b and 32d penetrate the molten aluminum 22 from the top to the bottom, contrary to the above. In this state, when the permanent magnets 32a to 32d are rotated in a certain direction, the molten aluminum 22 is rotated. As a result, the molten aluminum 22 is sufficiently agitated with a complicated movement in the furnace body 22 in combination with the presence of the protrusion 34. FIG. 1 shows an example of a state in which stirring is performed, and it can be seen that centrifugal force is generated by stirring, the outer peripheral side of the molten aluminum 22 is raised, and the central portion is dented.
[0022]
As described above, when the aluminum charged into the furnace body 20 is melted by the burner 4 and progresses to the state of being stirred by the stirring mechanism 30, it is sufficient to sequentially add additional undissolved aluminum. Thereby, the newly introduced aluminum and the molten aluminum 22 are mixed violently and the dissolution rate is remarkably increased. In addition, the components of the molten aluminum 22 are made uniform.
[0023]
As described above, in the embodiment of the present invention, the force for rotating the molten aluminum 22 is obtained not from the electromagnetic coil through which the current flows but from the permanent magnet. It is no longer necessary to pass current. Along with this, naturally, a cooling device for heat generated due to a large current becomes unnecessary, and the overall manufacturing cost of the aluminum melting furnace 2 with a stirring device can be reduced. Thus, the running cost can be reduced by the amount not requiring a large current. For example, when stirring is performed using a conventional electromagnetic coil, power of 100 kw / h is required, whereas in this embodiment, 2.2 kw / h that is the driving power of the motor 43 is sufficient. Moreover, since the structure is simpler than that of a conventional electromagnetic coil type aluminum melting furnace, maintenance can be virtually eliminated.
[0024]
Furthermore, since the present invention uses a permanent magnet instead of the conventional electromagnetic coil as described above, it is not necessary to consider inductance, so that stirring at a high speed is possible, and by increasing the rotation speed of the motor 43, melting is performed. The aluminum 22 can be stirred at a high speed. That is, by controlling the rotation speed of the motor 43, the stirring speed of the molten aluminum 22 can be freely controlled.
[0025]
Further, since the magnetic shielding plate 34 is provided on the entire inner wall of the space 14a of the outer frame 10, it is possible to prevent the magnetic field from leaking to the outside of the outer frame 10, and to eliminate adverse effects on the outside and A magnetic field can be efficiently applied to the molten aluminum 22.
[0026]
Furthermore, since the adjacent polarities of the permanent magnets 32 are arranged differently, the molten aluminum 22 can be efficiently and sufficiently agitated as described above. In addition, since the protrusions 24 are provided on the inner wall of the furnace body 20, the molten aluminum 22 can be agitated with a complicated movement as shown by the solid line arrow A in FIG. The components of the aluminum 22 can be made uniform.
[0027]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible, for example, the permanent magnet 32 is not limited to four things of illustration, It can be made into arbitrary numbers.
[0028]
The position of the permanent magnet 32 is not limited to the position below the bottom 20 a of the furnace body 20, but may be a position outside the furnace body 20 and allowing the magnetic field of the permanent magnet 32 to reach the vicinity of the center of the molten aluminum 22. For example, a ring-shaped moving magnetic field generator is concentrically provided on the outer periphery of the side wall 20b shown in FIG. 1 so as to surround the outer periphery of the furnace body 20. This moving magnetic field generator has a plurality of permanent magnets 32 arranged at predetermined intervals in the circumferential direction, and is attached so that the polarity is alternately different toward the furnace body 20 in terms of polarity. This moving magnetic field generator is rotated by a motor or the like. In this case, since the magnetic fields generated by the permanent magnets 32 are alternately different in polarity, the furnace main body 20 is formed such that adjacent permanent magnets are connected to each other by magnetic lines of force when viewed from above the furnace main body 20. It penetrates the molten aluminum 22 inside. Thus, the molten aluminum 22 in the furnace body 20 can be agitated by rotating the magnetic lines of force while the magnetic lines of force penetrate the molten aluminum 22.
[0029]
Furthermore, the above-described stirring mechanism 30 can be used not only as the melting furnace but also as a stirring device for molten aluminum housed in various container-like ones.
[0030]
【The invention's effect】
According to the present invention, the permanent magnet is rotated and moved so that the magnetic lines of force from the permanent magnet are moved through the molten aluminum so that the molten aluminum is stirred. A large current to be supplied is not required, and a cooling device is also unnecessary. As a result, the manufacturing cost and running cost can be reduced. Moreover, there is no possibility of clogging of the cooling water passage of the coil, which has been easy to occur in the past, and maintenance can be virtually eliminated. In addition, the stirring speed can be easily controlled by changing the rotation speed of the permanent magnet, which makes it possible to stir at a significantly higher speed than before.
[Brief description of the drawings]
1 is a longitudinal cross-sectional view of an aluminum melting furnace with a stirring device to which the present invention is applied. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 4 is a plan view thereof. FIG. 5 is a diagram for explaining the operation principle.
2 Aluminum melting furnace with stirrer 4 Burner 10 Frame 20 Furnace body 22 Molten aluminum 24 Projection 30 Stirring mechanism 31 Magnet base 32 Permanent magnet 40 Moving magnetic field generator 41 Bearing 43 Motor

Claims (5)

A furnace main body for storing molten aluminum melted by heating from the outside;
The moving magnetic field generator is arranged so as to face the lower outer end face of the bottom of the furnace body, not on the outer periphery of the furnace body , but in the vertical direction. A plurality of permanent magnets that generate penetrating magnetic field lines penetrating through the molten aluminum, and the moving magnetic force is applied to the molten aluminum by moving the penetrating magnetic field lines substantially vertically through the molten aluminum as the permanent magnets rotate. And is configured to stir in the furnace body,
The moving magnetic field generator includes:
A bearing provided in a fixed state with respect to the furnace body;
A magnet base as a rotating plate that is rotatably supported about an axis that runs substantially up and down by the bearing;
The plurality of permanent magnets arranged circumferentially on the magnet base so that different poles are alternately arranged on the surface facing the furnace body, and
Configured as
An aluminum melting furnace with a stirring device.   The aluminum melting furnace with a stirrer according to claim 1, wherein a protrusion for efficiently stirring the molten aluminum by the moving force is provided on an inner surface of the furnace body.   The substantially cylindrical chassis is divided into upper and lower portions by a partition wall, the furnace main body is stored in a space above the partition, and the moving magnetic field generator is stored in a space below the main body. An aluminum melting furnace with an agitator as described. This is a molten aluminum stirrer that is arranged so as to face the lower outer end surface of the bottom of the furnace body, not vertically on the outer periphery of the furnace body that stores molten aluminum melted by external heating. And having a plurality of permanent magnets that generate penetrating magnetic lines penetrating the molten aluminum in the furnace body substantially vertically, and the penetrating magnetic lines penetrate the molten aluminum substantially vertically as the permanent magnet rotates. It is configured to stir in the furnace body by applying a moving force to the molten aluminum by moving in the state
A bearing provided in a fixed state with respect to the furnace body;
A magnet base as a rotating plate that is rotatably supported about an axis that runs substantially up and down by the bearing;
The plurality of permanent magnets arranged circumferentially on the magnet base so that different poles are alternately arranged on the surface facing the furnace body, and
Configured as
A molten aluminum stirrer characterized by the above. A molten aluminum stirring method for stirring molten aluminum in a furnace body in an aluminum melting furnace,
The molten aluminum stirring device, not on the outer periphery of the furnace body, down, to face up and down the lower outer end surface of the bottom of the furnace body was placed, as the molten aluminum stirrer,
A bearing provided in a fixed state with respect to the furnace body;
A magnet base as a rotating plate that is rotatably supported about an axis that runs substantially up and down by the bearing;
A plurality of permanent magnets arranged circumferentially on the magnet base so that different poles are alternately provided on the surface facing the furnace body, and
Use the one with
The magnetic field lines of the plurality of permanent magnets are penetrated through the molten aluminum in the furnace body in a substantially vertical direction,
In this state, the plurality of permanent magnets are rotated together with the magnet base, and the magnetic lines of force are rotationally moved in a state of penetrating the molten aluminum substantially vertically, thereby applying a moving force to the molten aluminum in the furnace body. Stirring around an axis that runs almost vertically,
A molten aluminum stirring method characterized by the above.

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