JP2972787B2 - Floating melting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which an object to be heated such as metal is placed in a crucible made of a segmented conductive material inside an induction coil, thereby floating the metal from the crucible and melting it in a floating state. And a floating melting device.

[0002]

2. Description of the Related Art Since impurities from a crucible are not mixed into a metal melted by the floating melting method, a high-purity molten metal can be produced. The molten metal is poured into a mold to produce an extremely high-quality product. For example, used for dissolving titanium, silicon and the like.

FIG. 6 is a partial cross-sectional perspective view of a conventional example. In the figure, a conventional levitation and melting apparatus has a circular induction coil 1.
A crucible 3 in which a plurality of segments 2 made of a conductive material such as copper which is electrically insulated is arranged in the circumferential direction of the induction coil 1. The inside of the crucible 3 is hollowed out to form a bottomed cylindrical shape, and an object to be heated such as metal is put in this portion.
A small cylindrical hole 4 is formed in the center of the bottom of the crucible 3, and the magnetic flux penetrates into the crucible through the slit 5 between the hole 4 and the segment 2 and interlinks with the object to be heated.
In order to cool the segment 2 with water or the like, the segment 2 has an axial water path (not shown), and a pump for supplying a cooling liquid is arranged near the crucible 3 in addition to a frequency converter and a transformer for supplying power. Is done. The slit 5 between the segments 2 is filled with an insulating material.

The current of the induction coil 1 induces an eddy current in each of the electrically insulated segments 2 and also induces an eddy current in the object to be heated. For this reason, the direction of the eddy current flowing through the crucible 3 and the object to be heated is opposite to each other at the opposing surface portions, and a magnetic repulsive force is generated.
Since the crucible 3 is fixed, if the levitation force acting on the object to be heated is greater than the weight of the object to be heated, the object to be heated floats away from the crucible 3. Since the eddy current of the object to be heated 6 generates heat due to resistance loss and continues heating, the object to be heated melts in a floating state.

[0005]

According to the above-mentioned conventional example, the segments 2 cause mutual electromagnetic vibration, the insulating material filling the slit 5 is worn down, the thickness is reduced, and the gap between the slits 5 is not uniform. Is generated, the magnetic flux passing through the slit 5 becomes non-uniform. For this reason, the levitation of the object to be heated which is subjected to the levitation force by the magnetic flux is not stabilized. If the insulating material is extremely worn, the insulating material may fall off and the crucible 3 may be broken.

Further, since the water supply pipe of the pump for supplying the cooling liquid is connected to the water channel of each segment 2 by sewing between the frequency conversion device for power supply and the transformer, the fluid resistance of the water supply pipe for each segment 2 is reduced. Differently, the flow rate of the coolant flowing through the water passage of each segment 2 is different. Therefore, each segment 2
Of the eddy currents induced in the respective segments 2. After all,
The levitation of the object to be heated which receives a levitation force due to the uneven eddy current is not stable. If the flow rate decreases too much, the coolant may boil and induce a steam explosion in waterways and pipes.

SUMMARY OF THE INVENTION An object of the present invention is to make the gap between the slits of the segments and the flow rate of the coolant of the segments uniform so that the magnetic flux and the eddy current are made uniform and the floating of the object to be heated can be stabilized. An object of the present invention is to provide a levitation melting apparatus capable of easily charging an object to be heated into a crucible.

[0008]

According to a first aspect of the present invention, there is provided a levitation melting apparatus in which a crucible made of a bottomed cylindrical conductive material provided inside an induction coil is formed from a plurality of segments divided in a circumferential direction through slits. In the floating melting device, the bottoms of the segments are connected to each other by a connecting member, and the slit at the top of the segment, which is constrained in the axial direction by the annular member, cuts into the concave portion of the adjacent segment and is formed of an insulating material. It pushes a pin.

A floating melting apparatus according to a second aspect of the present invention is a floating melting apparatus in which a crucible made of a bottomed cylindrical conductive material provided inside an induction coil is formed from a plurality of segments circumferentially divided through slits. A tank is arranged near the upper or lower part of the crucible on the cooling liquid supply side of each segment having an axial waterway, and this tank and each waterway are connected by a water supply pipe with fluid resistance that approximates each other. It is.

A floating melting apparatus according to a third aspect of the present invention is a floating melting apparatus in which a crucible made of a bottomed tubular conductive material provided inside an induction coil is formed from a plurality of segments circumferentially divided through slits. A tank is arranged near the upper or lower part of the crucible on the cooling liquid discharge side of each segment having an axial waterway, and this tank and each waterway are connected by a drain pipe with fluid resistance that approximates each other. It is.

A fourth aspect of the present invention is the invention according to the second or third aspect, wherein the tank is disposed above or below the crucible as a hollow ring coaxial with the crucible. In a fifth aspect of the present invention, in the fourth aspect, the hollow annular tank above the crucible is formed of a conductor.

[0012]

According to the first aspect of the present invention, the bottom of the crucible is joined by the joining member. At the upper part of the segment constrained in the axial direction by the annular member, the gap between the slits is reliably maintained at a uniform size by the pin pushed into the recess of the segment. For this reason, the magnetic flux passing through the slit becomes uniform, and the floating of the object to be heated is stabilized. Also,
Since the coupling is strong and the electromagnetic vibration is suppressed, there is no wear of the pin made of the insulating material, and there is no fear of breaking the crucible.

According to the floating melting apparatus of the second aspect, since the tank is arranged close to the crucible, the water supply pipe connecting the tank and each water channel has fluid resistances which are close to each other. For this reason, the flow rate of the water channel of each segment connected to the tank which maintains a constant water supply pressure becomes uniform, and cooling becomes uniform. As a result, the temperature and electric resistance of each segment become uniform, the eddy current becomes uniform, and the floating of the object to be heated is stabilized. In addition, there is no danger that a water channel with a shortage of the cooling liquid is generated and a steam explosion is induced.

The operation of the levitation melting apparatus according to the third aspect of the invention is the same as that of the third embodiment except that the water supply pipe is replaced with a drain pipe and the water supply pressure is replaced with the drain pressure. According to the fourth aspect, the tank is arranged coaxially above or below the crucible in a hollow annular shape, so that the fluid resistance of the water supply pipe or the drain pipe becomes completely the same, and the cooling becomes completely uniform. The floating of the object to be heated is further stabilized. Further, all the water supply pipes or drain pipes connecting the tank and the water channel have the same shape, so that the structure is simplified.

According to the fifth aspect, the tank made of the conductor is 1
As the turns are formed and the magnetic flux therearound is counteracted, the magnetic flux of the induction coil passes above the crucible and between the annular tank and the magnetic flux inside the tank is significantly reduced. For this reason,
No induced electromotive force is generated in the object to be heated from above, and the object to be heated falls straight down without being flipped and is surely inserted into the crucible.

[0016]

FIG. 1 is a perspective view showing a half section of the first embodiment, and FIG.
3 is a longitudinal sectional view of the tank of FIG. 1, FIG. 4 is a perspective view of the pin of the second embodiment, and FIG. 5 is a perspective view of the pin of the third embodiment. In the prior art and in each drawing, components having the same reference numerals have approximately the same functions. 1, 2 and 3, the levitation and melting apparatus includes a plurality of segments 2 made of a conductive material such as copper which is electrically insulated in a circumferential direction of the induction coil 1 inside a circular induction coil 1. The crucibles 3 are arranged side by side. The inside of the crucible 3 is hollowed out to form a bottomed cylinder, into which an object to be heated 10 such as metal is placed. A small cylindrical hole 4 is formed in the center of the bottom of the crucible 3, and the magnetic flux penetrates into the crucible through the slit 5 between the hole 4 and the segment 2 and interlinks with the object 10 to be heated. In order to cool the segment 2 with water or the like, an axial water passage 6 is provided in the segment 2. Then, the frequency converter 7 is connected to the induction coil 1.

A feature of this embodiment is that the center of the bottom of the segment 2 is connected to a connecting member 11 made of an insulating material or the like.
Is connected via the connecting pin 11a. An axial pin 13 made of an insulating material is pushed into the slit 5 at the upper part of the segment 2 so as to bite into the recess 12 of the adjacent segment. A hollow annular tank 14 coaxial with the crucible 3 is arranged near the lower part of the crucible 3 which is the supply side of the cooling liquid of each segment 2 having the water passage 6 in the axial direction. Are connected by a water supply pipe 15. Further, a hollow annular tank 16 coaxial with the crucible 3 is arranged near the upper part of the crucible on the discharge side of the cooling liquid, and this tank 16 and each water passage 6 are connected by a drain pipe 17. A cooling liquid supply pump (not shown) is connected to the lower tank 14 and the upper tank 1
The cooling liquid of No. 6 is circulated to the pump via a not-shown cooler, or returned once to a liquid storage tank opened to the atmosphere.

According to such a structure, the plurality of segments 2 divided in the circumferential direction through the slits 5
The gap 13 of the slit 5 is reliably held at a uniform size by the pin 13 which is constrained in the axial direction by the hollow annular tank 16 via the groove 7 and is pushed into the concave portion 12 of the segment 2. Therefore, the magnetic flux passing through the slit 5 becomes uniform, and the floating of the object to be heated 10 is stabilized. Further, since the coupling is strong and suppresses electromagnetic vibration, the pin 13 made of an insulating material is used.
There is no wear of the crucible 3 and there is no danger of breaking the crucible 3. Since the upper and lower hollow annular tanks 16 and 14 make the drainage pressure and the water supply pressure to each water passage 6 of the segment 2 uniform, the temperature and electric resistance value of each segment 2 become uniform, and the eddy current becomes uniform. And the floating of the object to be heated 10 is stabilized. In addition, there is no danger that the water channel 6 with a shortage of the cooling liquid is generated and a steam explosion is induced. If the upper hollow annular tank 16 is made of a conductor, one turn is formed to cancel the magnetic flux around it, so that the magnetic flux of the induction coil 1 passes between the upper part of the crucible 3 and the annular tank 16. , Tank 16
Is significantly reduced. For this reason, no induced electromotive force is generated in the object to be heated 10a to be charged from above, and the object to be heated 10a falls straight without being flipped and is reliably charged into the crucible 3.

A modification of the above embodiment will be described. The pin 13 may be tapered like the pin 43 in FIG.
It can be squared as in 3. The tank 16 may be on the water supply side and the tank 14 may be on the discharge side. The tanks 16 and 14 may be formed in a rectangular shape or the like instead of being formed in an annular shape, disposed adjacent to the upper or lower side of the crucible, and connected to each water passage 6 by drainage or water supply pipes of different lengths. Since the drainage pipe and the water supply pipe have different lengths, the difference in fluid resistance is small. Since the tank at this time does not bind the plurality of segments 2 like the hollow annular tank 16 in the axial direction, the outer periphery of the crucible 3 may be joined with an annular member such as a heat-resistant insulating cord or a tape. I just need. Segment 2
It is not necessary that the coupling member 11 at the bottom is made of an insulating material. If the lower end of the induction coil 1 is located sufficiently above the bottom, a conductive material is used for the coupling member 11 and a hole through which magnetic flux passes through the lower portion of the slit 5. Substitute for 4. At this time, the slit 5 can be formed in one conductor including the crucible 3 and the coupling member 11 by machining. When a pump or a liquid storage tank is close to the water channel 6, the tank 16 or 14 is not required. Instead of connecting the bottom of the segment 2 with the connecting member 11, a structure similar to that of the pin 13 at the top of the segment 2 can be adopted.
At this time, the rigidity around the hole 4 may be maintained by using the coupling pin 11a.

[0020]

According to the levitation melting apparatus of the first aspect, the gap between the slits of the segments is kept uniform, and the magnetic flux becomes uniform, so that the levitation of the object to be heated is stabilized. In addition, since the coupling is strong and the electromagnetic vibration is suppressed, there is an effect that there is no wear of the pin made of the insulating material and there is no possibility of breaking the crucible.

According to the floating melting apparatus of the second aspect, the flow rate of the water channel of each segment becomes uniform, the cooling becomes uniform, the electric resistance becomes uniform, and the eddy current becomes uniform. Has the effect of stabilizing. In addition, there is also an effect that there is no danger that a water channel with a shortage of the cooling liquid is generated and a steam explosion is induced. The effect of the floating melting device of the third aspect is the same except that the water supply pipe is replaced by the drainage pipe and the water supply pressure is replaced by the drainage pressure.

According to the fourth aspect, there is an effect that the fluid resistance of the water supply pipe or the drain pipe becomes completely the same, the cooling becomes completely uniform, and the floating of the object to be heated is further stabilized. Further, there is an effect that all the water supply pipes or drain pipes connecting the tank and the water channel have the same shape, and the structure is simplified. Invention 5
According to the above, the tank made of a conductor forms one turn and cancels the magnetic flux around it, and the magnetic flux inside the tank is remarkably reduced, so that the object to be heated from above is straightened without being flipped. There is an effect that it falls into the crucible and is surely thrown into the crucible.

[Brief description of the drawings]

FIG. 1 is a half sectional perspective view of a first embodiment.

FIG. 2 is a perspective view of the segment of FIG. 1;

FIG. 3 is a longitudinal sectional view of the tank of FIG. 1;

FIG. 4 is a perspective view of a pin according to a second embodiment.

FIG. 5 is a perspective view of a pin according to a third embodiment.

FIG. 6 is a partial cross-sectional perspective view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Induction coil 2 Segment 3 Crucible 4 Hole 5 Slit 6 Waterway 10 Heated object 10a Heated object 12 Depression 13 Pin 14 Tank 15 Water supply pipe 16 Tank 17 Drain pipe

Continuation of the front page (72) Inventor Kazuyuki Sakuraya 2-3-12 Nakameguro, Meguro-ku, Tokyo Inside the National Institute of Metals Science and Technology (72) Inventor Toshiaki Watanabe 2-3-3 Nakameguro, Meguro-ku, Tokyo No. 12 Japan Institute of Science and Technology Metal Materials Research Laboratory (72) Inventor Satoshi Iwasaki 2-3-12 Nakameguro, Meguro-ku, Tokyo Japan Science and Technology Agency Inside Metal Materials Research Laboratory (72) Inventor Motoo Yamazaki Hamamatsu, Shizuoka Prefecture 4937-3, Handa-cho, City (72) Kimi Morita 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Tatsuo Take 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki, Kanagawa, Japan No. Fuji Electric Co., Ltd. (72) Inventor Mitsuru Fujita 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) F27B 14 / 06,14 / 10

Claims (5)

(57) [Claims] 1. A floating melting apparatus in which a crucible made of a bottomed cylindrical conductive material provided inside an induction coil is formed from a plurality of segments divided in a circumferential direction through slits, wherein the bottoms of the segments are mutually connected. A levitation melting apparatus characterized in that an axial pin made of an insulating material cuts into a concave portion of an adjacent segment and is pushed into the slit at an upper portion of a segment which is connected by a connecting member and constrained in an axial direction by an annular member. 2. A floating melting apparatus in which a crucible made of a bottomed cylindrical conductive material provided inside an induction coil is formed from a plurality of segments divided in a circumferential direction through slits, and has a water path in an axial direction. Floating melting characterized by disposing a tank in the vicinity of the upper or lower part of the crucible on the supply side of the cooling liquid of each segment, and connecting this tank and each water channel with a water supply pipe having a fluid resistance similar to each other. apparatus. 3. A floating melting apparatus in which a crucible made of a bottomed cylindrical conductive material provided inside an induction coil is formed from a plurality of segments divided in a circumferential direction through slits, and has a water path in an axial direction. Floating melting characterized by disposing a tank close to the upper or lower part of the crucible on the cooling liquid discharge side of each segment, and connecting this tank and each water channel with drainage pipes having fluid resistances similar to each other. apparatus. 4. The flotation melting apparatus according to claim 2, wherein the tank is arranged above or below the crucible as a hollow ring coaxial with the crucible. 5. The flotation melting apparatus according to claim 4, wherein the hollow annular tank above the crucible is formed of a conductor.