JPH0814761A - Tilting device for vacuum induction melting furnace by non-contact power feeding - Google Patents

Abstract

PURPOSE:To prevent the contamination of a molten metal with the gas generated by the exposure to a high temperature and a high degree of vacuum inside a vacuum container of the insulating covering material of a flexible insulating cable which is adaptable to the tilting conditions of a furnace body in pouring the molten metal into a casting mold or the lowering of the purity of a metal or alloy melted by reducing the degree of vacuum inside the vacuum container. CONSTITUTION:A non-contact power feeder 16 of pot type fitted with a pair of a primary core 16a and a secondary core 16b is provided in a vacuum container 20, connecting conductors 17 and 18 are provided to electrically connect an external electric source 19 and an induction heating coil 13 via the non- contact electric feeder 16, a water cooled copper pipe or bus bar is used in the portions of the connecting conductors 17 and 18 disposed in the vacuum container 20 and the furnace body 11 of an induction melting furnace 10, the secondary core 16b and the connecting conductor 18 are secured by non- conductive support members.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace body tilting device of a vacuum induction melting furnace arranged in a vacuum vessel of a vacuum induction melting device for melting a high-purity metal or alloy, and more specifically to an induction heating coil. The present invention relates to a furnace tilting device of a vacuum induction melting furnace, which electrically connects a vacuum induction melting furnace with an external power source.

[0002]

2. Description of the Related Art FIG. 7 is a schematic sectional view showing the main part of a vacuum induction melting apparatus according to the prior art. A conventional melting method using a vacuum induction melting apparatus will be described with reference to FIG. 7. A furnace body 71 is arranged in a vacuum induction melting furnace 70 in a vacuum container 80 or a vacuum chamber (also referred to as a chamber). The induction heating coil 73 provided on the outer periphery of the furnace is supplied with power from an external power source 79 provided outside the vacuum container 80 to melt the material to be melted of metal or alloy under a predetermined reduced pressure, and when melting is completed, the furnace body 71 is heated. The tilting shaft of the tilting device (not shown) is rotated about the one-dot chain line Y as a central axis as indicated by arrow R1 to tilt the furnace body 71, and the molten metal m inside the furnace body 71 is cast into a casting mold or It is poured and cast in the ingot mold 75. Since it is necessary to tilt the furnace body 71 in order to cast the molten metal m in this way, the connection conductor 77 for supplying a high current from the external power source 79 to the induction heating coil 73 is
The furnace body 71 has flexibility so that it can be deformed in conformity with the tilting of the furnace body 71, and it has an insulating property with respect to the outside.
A flexible cable using an insulating coating material having heat resistance capable of protecting the cable is used.

According to JIS C 4003, as an insulating material for an insulating coating layer of a flexible cable having heat resistance used in a vacuum induction melting furnace of a vacuum induction melting apparatus, for example, an allowable maximum temperature of 155 ° C. Against, mica, asbestos,
It is recommended to use a composite of glass fiber, etc. with silicone, alkyd resin, polyester imide, etc. For the maximum allowable temperature of 180 ° C, mica, asbestos, glass fiber, etc. composite with silicon resin, heat resistance Polyester, polyimide, polyamide-imide, etc. are recommended and are used in vacuum induction melting furnaces. On the other hand, in a vacuum induction melting furnace, the furnace body is made of a refractory material
There are two types, a cold-wall type and a cold-wall type in which the furnace body is water-cooled. FIG. 8 is a sectional view of the main part showing an example of the cold wall melting furnace. In the cold wall melting furnace 90, cooling water passages 82a (inlet side) and 82b (inlet side) are provided inside a side wall 81a and a bottom wall 81b of a furnace body 81 made of metal such as copper having a large thermal conductivity. Outlet side) and the induction heating coil 83 is spirally wound on the outer peripheral side of the side wall 81a, and the furnace body 81 suppresses the temperature rise of the molten metal m or the temperature rise of the furnace body 81 due to induction heating by water cooling. are doing. In this figure, the side wall 81a is formed by a plurality of segments 86 divided by a gap (slit) 85 having a predetermined width in the circumferential direction.

[0004]

With the increasing demand for melting metals and alloys of higher purity than ever before, the atmosphere in the vacuum vessel should be decompressed as much as possible, that is, the degree of vacuum should be as high as possible. It becomes necessary to insulate the cable as a connection conductor placed in an environment where the temperature is raised by conduction heat or radiant heat through the induction heating coil and the connection conductor itself under such a high vacuum degree. Since the insulating material to be coated is composed of mica, asbestos, glass fiber and synthetic resin as a heat resistant material, gas such as water vapor mainly adheres to the surface layer and is released into the atmosphere as the vacuum becomes higher. Is easily absorbed and contaminated the molten metal as an impurity, or these gases are released into the atmosphere one after another to increase the internal pressure in the vacuum container and maintain the inside of the vacuum container at a predetermined level. It makes it difficult to maintain the pressure,
Are causing problems. In particular, in a furnace whose mission is to melt high-purity metals such as a cold wall melting furnace, prevention of contamination of the molten metal and maintenance of a high vacuum are the most important requirements, and the above problems have a great influence. Therefore, it is expected that ceramics or the like, which emits less gas even when exposed to high temperature and high vacuum, is used as the insulating coating layer. However, as a characteristic of the flexible cable, it is also used as the insulating material forming the insulating coating layer. Since flexibility is required, it is impossible to use ceramics which are hard and lack flexibility from this point. It is an object of the present invention to develop an induction melting furnace having a tilting device that electrically connects an induction heating coil and an external power source and allows tilting of a furnace body without such a problem of gas release. And

[0005]

According to the present invention, in a vacuum induction melting apparatus, between an induction heating coil arranged on the outer circumference of a furnace body or a crucible of a vacuum induction melting furnace and an external power source arranged outside the vacuum vessel. And a pot-type transformer non-contact power supply device, which is arranged to face each other with a predetermined interval, and which includes a primary core and a secondary core around which electromagnetic coils are wound. , An induction heating coil and an external power source are electrically connected via a non-contact power feeding device, and a water-cooled copper pipe or a water-cooled copper bus bar is connected between the induction heating coil and the electromagnetic coil of the secondary side core of the non-contact power feeding device. Connect with-and 2
The secondary side core is tilted with the coaxial rotational symmetry axis of the primary side core and the secondary side core as the central axis of rotation, so that even when the furnace body is tilted, the secondary side of the contactless power supply device is tilted. Since only a part rotates about the above-mentioned rotational symmetry axis as a central axis, it follows the tilting while being supplied with power, so that a flexible cable having an insulating coating layer in a vacuum container as in the prior art is used. It eliminates the need for use, and solves the problem of pressure increase in the vacuum container due to gas release from the insulating coating layer and the contamination of the molten metal by the gas.

If necessary, a water-cooled copper pipe or a water-cooled copper bus bar for connecting the induction heating coil and the secondary core.
And / or by fixing the core on the secondary side and the furnace body with a support member made of an insulating material such as ceramics,
Deformation of the water-cooled copper pipe or water-cooled copper bus bar during tilting is surely prevented. The above-mentioned non-contact power supply device can be arranged inside the vacuum container or with the wall of the vacuum container interposed therebetween. In either case, a water-cooled copper pipe or a water-cooled copper busbar is used as a connecting conductor between the induction heating coil and the electromagnetic coil of the secondary side core.
For the connecting conductor between the electromagnetic coil of the secondary core and the external power source, use a water-cooled copper pipe or water-cooled copper busbar only in the part inside the vacuum container, and use a normal water-cooled cable in the part outside the vacuum container. Cable or insulated cable can be used. The present invention has solved the problem by the above configuration.

[0007]

The water-cooled copper pipe or the water-cooled copper busbar connected to the induction heating coil and the electromagnetic coil of the secondary core of the non-contact power feeding device is attached to a supporting plate made of ceramics or the like fixed to the furnace body. Following the tilting of the body, it is rotated about the rotational symmetry axis of the primary side core and the secondary side core of the pot type transformer non-contact power supply device. It is possible to solve the problem of gas release from the insulating coating layer without using a cable, and a vacuum induction melting furnace under high vacuum, especially a cold wall melting furnace using a water-cooled segment crucible made of conductive metal. To ensure the melting of high-purity metals or alloys in.

[0008]

1 is a schematic sectional view of a main part of an induction melting furnace in which a non-contact power feeding device is arranged in a vacuum container as a first embodiment of the present invention. Although the non-contact power feeding device can be arranged inside the vacuum container or on the wall portion of the vacuum container, the case where the non-contact power feeding device is arranged inside the vacuum container is shown as the first embodiment. An example of installing the device will be described later. A first embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 10 is a normal vacuum induction melting furnace, reference numeral 11 is a furnace body, and a core 16a on the primary side of the non-contact power supply device 16 and The melt m that has been rotated by a predetermined angle in the direction of the arrow R with the common rotational symmetry axis of the secondary side core 16b as the rotation center axis X and has finished the predetermined melting operation inside the furnace body 11 It is poured into an ingot mold 15 or a conventional casting mold (not shown). The non-contact power feeding device 16 of the present invention is, for example, a pot type transformer as shown in the drawing, and the electromagnetic coil 2 wound around the core 16a on the primary side thereof.
4a is connected to the external power source 19 and its connecting conductor 17
The portion inside the vacuum container 20 of the above shall use a water-cooled copper pipe or a water-cooled copper bus bar. Although not shown, all of the secondary cores and connecting bodies of the power supply devices of the following embodiments of the present invention are similar to those shown in FIG. 1, but the primary core and the secondary core are the same. It is rotated with a common rotational symmetry axis as the central axis of rotation.

On the other hand, the electromagnetic coil 24b on the secondary side is connected to the induction heating coil 13 of the induction melting furnace 10 by a water-cooled copper pipe or a water-cooled copper bus bar as the connecting conductor 18.
The core 16b on the secondary side and the connecting conductor 18 are attached to the furnace body 11 by a supporting member such as ceramics and are rotated integrally with the vacuum induction melting furnace 10 as the vacuum induction melting furnace 10 is tilted. It is not necessary to use, and if necessary, ceramics or the like can be used as the insulating coating material. The connecting conductors 17 inside and outside the vacuum container 20 are hermetically sealed inside the vacuum container 20 via a conductor embedded in a disk 20a made of an insulating material provided on an intermediate flange portion of the vacuum container 20. Be electrically connected to each other without breaking. FIG. 2 is a perspective view of the contactless power feeding device 16. Further, FIG. 3 is a sectional view showing a magnetic flux φ generated in the non-contact power feeding device 16. This magnetic flux φ reverses the direction at the same time as the direction of the current flowing through the primary coil is reversed. The contactless power supply device will be briefly described with reference to FIGS. 2 and 3.
As shown in FIG. 2 as a perspective view and the cross-sectional view of FIG. 3 showing magnetic flux, this non-contact power feeding device 16 called a pot-type transformer has a pair of cylindrical shapes with a bottom and an E-shaped cross section. Bottom portions 23a, 23b of the pot-shaped cores 16a, 16b, cylindrical peripheral walls 21a, 21b provided on the outer peripheral portions of these bottom portions 23a, 23b, and the axial center portion of each bottom portion to the peripheral walls 21a, 21b. Projections 22a and 22b that respectively project inward in the axial direction in parallel, and an electromagnetic coil 24 wound around the outer circumferences of these projections 22a and 22b.
a and 24b.

The electromagnetic coil 24a is connected to an external power source to
When the secondary side is set, the magnetic flux φ of the magnetic field generated by the current flowing through the primary-side electromagnetic coil 24a is radially outward from the protrusion 22a toward the axially outward direction, passes through the bottom portion 23a, and further toward the peripheral walls 21a on both upper and lower sides. Flow toward the side walls 21b of the secondary side cores 16b which are arranged facing each other with a predetermined interval, and further flow to the protrusions 22b through the bottom 23a. Side core 16
reflux to a. This magnetic flux φ reverses the direction at the same time as the direction of the current flowing through the primary coil is reversed. Due to this magnetic flux φ, the induced current generated in the electromagnetic coil 24b on the secondary side is
Connection conductor 18 with water-cooled copper pipe or water-cooled copper busbar
The material to be melted, which is supplied to the induction heating coil 13 (see FIG. 1) through and is loaded into the furnace body 10, is induction-heated. FIG. 4 is a schematic sectional view showing a second embodiment of the present invention, and the illustration of the furnace body and the external power source is omitted because they are the same as those of the first embodiment. In this embodiment, the primary side electromagnetic coil 3
4a and the electromagnetic coil 34b on the secondary side, between the vacuum container 3
For example, a disk-shaped wall 31a, which is airtightly fixed to the flange portion 31 of 0 with bolts 35 or the like via an O-ring 33, is arranged, and as a connection conductor 17a between the electromagnetic coil 34a on the primary side and an external power source, It is connected with a normal water-cooled cable or a normal insulating cable.

Primary side cores 26a and 2 facing each other
The material of the wall 31a between the core 26b on the secondary side is preferably a non-conductive material in order to reduce the leakage of the magnetic flux φ and keep a large current generated on the secondary side. In FIG. 4, the vacuum container 30 is provided with a flange portion 31, and the flange portion 31
The wall 31a is fixed to the wall 31a, but as another embodiment of the second embodiment, the same can be achieved by hermetically attaching the wall made of the same material as the wall 31a to the vacuum container by using another method such as screwing or brazing. The effect is obtained. FIG. 5 is a schematic sectional view showing a third embodiment of the present invention. In this embodiment, 1
Between the inner peripheral surface of the peripheral wall 41a of the core 36a on the next side and the outer peripheral surface of the protruding portion 42a at the center, the O-ring 4 is formed on both inner and outer surfaces.
Sealing is performed by an annular seal member 47 in which 5a and 45b are fitted. Similar to the second embodiment, the core 36
An O-ring 48 is arranged between the outer circumference of the peripheral wall 41a of a and the vacuum container 40 to seal the inside of the vacuum container 40 from the outside atmosphere. Therefore, as the connecting conductor 17b between the primary-side electromagnetic coil 44a and the external power source, a normal water-cooled copper pipe or an insulating cable can be used for connection.

The seal member 47 of this embodiment is preferably non-conductive. Further, in order to prevent the magnetic flux generated by the electromagnetic coil 44a on the primary side from leaking to other than the member on the secondary side, the vacuum container 40 and the core 36a on the primary side are provided.
The core 3 on the secondary side is formed by increasing the distance from the outer periphery of the peripheral wall 41a or by configuring only the portion close to the core 36a on the primary side of the vacuum container 40 with a non-conductive material.
It is preferable to increase the magnetic flux flowing in 6b. In addition,
Although simplified in FIG. 5, the seal member 47 and the primary side core 36a are drawn inward of the vacuum container 40 due to the pressure difference between the internal pressure of the vacuum container 40 and the external atmospheric pressure. It is necessary to dispose the locking members 50 and 51 made of a non-conductive material so that there is no such problem. FIG. 6 is a schematic sectional view showing a fourth embodiment of the present invention. In the figure, members having the same effects as the members shown so far are not designated by reference numerals.
In this embodiment, the vacuum container 67, which is made of a non-conductive material only in the portion close to the core 66a on the primary side, is hermetically sealed via a seal material such as an O-ring 61 by the same means as in the second embodiment. The secondary-side core 66b is arranged so as to face the fixed primary-side core 66a with a predetermined gap. In this case, the connecting conductor 1 on the bottom 63a of the core 66a on the primary side
A pair of seal members 63c is provided at a portion where 7c is introduced in order to keep airtightness in the vacuum container. Connection conductor 17c
When a water-cooled copper pipe or a water-cooled copper bus bar is used for the connector, the connector 17 is arranged axially outside the core on the primary side.
It is connected to the connection conductor 17e by an insulating cable or the like from the external power source 19 via d. The connector 17d is provided with a water supply / drainage port (not shown) for the water-cooled copper pipe or the like.

Each of the above-mentioned embodiments refers to a hot-wall type vacuum induction melting furnace in which a furnace body made of ceramics such as alumina or magnesia is used to heat a charged material such as a metal to be melted. Although described, it is preferably applicable to the cold wall melting furnace shown in FIG. In the cold wall melting furnace, cooling water is supplied to the inside of the furnace body to suppress the temperature rise of the furnace body, and copper etc. can be used as a furnace body material. Since it is possible to prevent the chemical reaction from occurring in the molten metal and to mix it into the molten metal, the above-mentioned respective embodiments can be similarly applied to a vacuum induction melting furnace using a cold wall melting furnace. Also in such a cold wall melting furnace, the power feeding method and tilting mechanism are the same as those of the hot wall type induction melting furnace in each of the above-mentioned embodiments, and the induction melting furnace of each of the above-mentioned embodiments is -The same effect can be obtained by replacing with a Rudwall melting furnace.

[0014]

According to the present invention, a non-contact power supply device using a pot type transformer is used, at least the core on the secondary side is provided inside the vacuum container, and a water-cooled copper pipe or a water-cooled copper bus bar is used for the connection conductor on the secondary side. Since these members on the secondary side are fixed to the furnace body by a supporting member made of ceramics or the like so as to be rotatable following the furnace body, a flexible insulating case that releases gas in high temperature and high vacuum is used. -Bur is unnecessary and prevents the generation of the above-mentioned gas in the vacuum container, prevents the pressure rise in the vacuum container due to the released gas, and prevents the contamination of the molten metal. Dissolution became possible.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a main part of an induction melting furnace in which a non-contact power supply device is arranged in a vacuum container as a first embodiment of the present invention.

FIG. 2 is a perspective view of a contactless power supply device.

FIG. 3 is a cross-sectional view showing a magnetic flux φ generated in the non-contact power feeding device.

FIG. 4 is a schematic sectional view showing a second embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a third embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a main part of a vacuum induction melting apparatus according to a conventional technique.

FIG. 8 is a sectional view of a main part showing an example of a cold wall melting furnace.

[Explanation of symbols]

 10 vacuum induction melting furnace 11 furnace body 13 induction heating coil 16 non-contact power supply device 16a, 26a, 36a, 66a primary side core 16b, 26b, 66b secondary side core 17, 17a, 17c, 17e, 18 connection conductor 19 External power source 20, 30, 40 Vacuum container 21a, 21b, 41a Peripheral wall 22a, 22b, 42a Projection part 23a, 23b, 63a Bottom part 31a, 40, 67 wall 33, 45a, 45b, 48, 61 O-ring 47 seal Member X rotational symmetry axis

Claims (7)

[Claims] 1. A furnace tilting device for a vacuum induction melting furnace, in which a metal or alloy is melted by a vacuum induction melting furnace housed in a vacuum container and connected to an external power source, and the furnace body is tilted to pour the molten metal. A core disposed on the outer periphery of the furnace body of the vacuum induction melting furnace and an external power source, and the core on the secondary side is separated from the core on the primary side to follow the tilting of the furnace body. And a water-cooled copper pipe or a water-cooled copper bus bar that connects the non-contact power feeding device and the induction heating coil, and is connected between the non-contact power feeding device and an external power source. A furnace tilting apparatus for a vacuum induction melting furnace by non-contact power supply, comprising: a conductor which is at least a water-cooled copper pipe or a water-cooled copper bus bar extending into the vacuum container. 2. The non-contact power feeding device has an E-shaped cross section, a pair of bottomed cylindrical cores having a peripheral wall on the outer peripheral side of a disk-shaped bottom, and a projecting portion at the center, each having a concave surface. A non-contact type transformer in which parts are opposed to each other and are symmetrically arranged at a predetermined interval, and the secondary side core is rotatable about a common rotational symmetry axis of the pair of cores. The furnace tilting apparatus for a vacuum induction melting furnace according to claim 1, wherein the contactless power feeding is used. 3. The non-contact power feeding according to claim 1, wherein the non-contact power feeding device has a core on the secondary side and a core on the primary side facing each other with the wall of the vacuum container interposed therebetween. Tilt device for vacuum induction melting furnace. 4. The non-conductive material according to claim 3, wherein the magnetic flux passage portion of the wall of the vacuum container sandwiched between the secondary core and the primary core is made of a non-conductive material such as ceramics. Tilt device for vacuum induction melting furnace by contact feeding. 5. The primary core of the non-contact power feeding device is sealed to the wall of the vacuum container from the atmosphere outside the vacuum container by welding, brazing, O-ring, or the like, and the primary core is sealed. 3. The furnace tilting apparatus for a vacuum induction melting furnace by non-contact power supply according to claim 1, wherein the core on the side penetrates the vacuum vessel and projects into the vacuum vessel. 6. A ring-shaped seal member made of a non-conductive material is disposed between an inner circumference of the peripheral wall of the primary side core and an outer circumference of the protruding portion via an O-ring. 5. The furnace body tilting device of the vacuum induction melting furnace according to the non-contact power supply described in 5. 7. The water-cooled copper pipe or water-cooled copper busbar.
7. The vacuum induction by non-contact power supply according to any one of claims 1 to 6, wherein a ceramic or the like that does not release gas even when the atmosphere in the vacuum container is depressurized and heated is used as the insulating coating. Tilt device for melting furnace.