JPS6339246Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of an electroslag melting furnace, and in particular to a structure that simplifies the pretreatment of a workpiece and makes it possible to downsize the apparatus.

Conventionally, as an electroslag melting furnace for melting and solidifying radioactive metal waste, non-consumable electrodes are placed in a water-cooled mold, electricity is passed through the molten slag between the electrodes, and the material to be processed is melted by Joule heating. Melting and solidifying treatment is performed. In this device, the material to be treated is introduced from above through between the electrodes, but depending on the size of the material, it may come into direct contact with both electrodes or indirectly through molten steel to prevent short circuits. This may cause the melting operation to become impossible. For this reason, in order to perform stable operations, it is necessary to input the material to be treated with a size suitable for the dimension between the electrodes, and pre-treatment of cutting the waste into pieces to that size is required, which requires large equipment. This may lead to increased complexity or complexity.

Therefore, in an electroslag melting furnace using a non-consumable electrode method, there is no short circuit between the electrodes;
There is a need for the development of a structure that allows for the introduction of as large a workpiece as possible.

This invention was made in order to solve such conventional problems, and it reliably prevents short circuits between electrodes due to input materials and eliminates the need for pretreatment.

That is, this idea is based on an electroslag melting furnace in which a non-consumable electrode is placed inside a water-cooled mold from above, and a cylindrical movable cover is inserted into the water-cooled mold from above so as to be movable up and down relative to the water-cooled mold. The non-consumable electrode penetrates vertically within the wall of the movable cover, its lower end protrudes below the movable cover, and the outer periphery of the electrode is covered with an insulator to electrically insulate it from the movable cover. It is something that exists.

Embodiments of this invention will be described below with reference to the drawings. The bottom of a copper water-cooled mold 1 is constituted by a water-cooled surface plate 2, a fixed cover 3 is attached to the top of the water-cooled mold 1, and a cylindrical movable cover 4 is inserted into the water-cooled mold 1 from above. The moving cover 4 is connected to the wire 5
0 and is configured to be raised and lowered by a winch 5. The outer peripheral surface of the movable cover 4 is slidably in contact with the inner peripheral surface of the fixed cover 3,
It is sealed with a packing 30. The movable cover 4 consists of an upper body 41 made of heat-resistant metal and a lower body 42 made of ceramic. An inward protrusion 43 formed at the lower end of the upper body 41 fits into an outward concave portion of the lower body 42, so that both can be separated. The inner circumferential surfaces of the upper body 41 and the lower body 42 are formed flush with each other, and an input port 40 into which the object to be processed is input is formed inside the upper body 41 and the lower body 42 . The reason why the lower part of the movable cover 4 is formed by the lower body 42 made of ceramic is to protect the movable cover 4 from the high temperature atmosphere inside the furnace.

Inside the wall of the movable cover 4 is an electrode 6 with a circular cross section.
penetrates vertically, and an insulating outer skin 60 made of ceramic is provided on the outer peripheral surface of the electrode 6 to connect the electrode 6 and the movable cover 4.
and are electrically insulated. The upper end of the electrode 6 is held by a flexible power supply plate 63, and the lower end projects below the movable cover 4. The reason why the power supply plate 63 is made flexible is to allow the electrode 6 to be lowered relative to the movable cover 4 when the electrode 6 is consumed. An operating means (not shown) is provided for this purpose. When the electrodes 6 are disposed so as to penetrate through the wall of the movable cover 4 in this manner, it is possible to easily set the electrode interval to the maximum.

In the above configuration, the water-cooled mold 1 may be moved up and down by supporting the water-cooled surface plate 2 by appropriate lifting means, and the movable cover 4 may be fixed.
Since the movable cover 4 is connected to a gas exhaust pipe, etc., if the movable cover is fixed, the structure of the connection portion with these can be simplified.

FIG. 2 shows another embodiment of this invention, in which an electrode 61 having a plate-like cross section is disposed to pass through the movable cover 44. An insulating outer cover 62 made of ceramic is provided on the outer peripheral surface of the electrode 61. The other configurations are the same as those in FIG. By configuring the electrodes to be flat in this manner, the electrode spacing can be set wider.

In the above configuration, the workpiece is charged into the furnace through the input port 40, and the electrode 6 is energized to melt the workpiece in the furnace by Joule heating. As a result of this melting, a layer of ingot 7 is formed in the lower part of the furnace, molten steel 70 is formed thereon, and a layer of molten slag 8 is further formed thereon. The movable cover 4 is moved by a winch 5 and an actuating means (not shown) to maintain a minimum distance from the hot water level, that is, the upper surface of the molten slag 8, and to keep the tip of the electrode 6 in the molten slag 8 at all times. The cover 4 and electrode 6 are raised and lowered. At the beginning of melting, the amount of material to be processed in the furnace is small, so the melt level is low;
As the melt level gradually rises due to melting and supply of the material to be treated, the movable cover 4 and electrode 6 are raised accordingly.

In this way, the material to be processed is supplied through the input port 40 on the inner surface of the movable cover 4, and since the movable cover 4 is electrically insulated from the electrodes 6, there is no possibility that a short circuit will occur between the electrodes due to the input material. can definitely be prevented. The reason why the distance between the lower end of the movable cover 4 and the hot water level is set as small as possible is to prevent the insulating outer skin 60 made of ceramic provided around the outer periphery of the electrode 6 from being destroyed by the thrown objects. The lower body 42, which is also made of ceramic, is always hit by the thrown objects, but since the lower body 42 is integrally formed as a whole, its strength is strong and there is no risk of damage.

As explained above, in this invention, a movable cover that can be raised and lowered is placed in the water-cooled mold of an electroslag melting furnace, and electrodes are placed through this wall. Short circuits can be reliably prevented, so there is no need to cut the object into pieces, and pretreatment of the object can be omitted.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an embodiment of this invention, Figure 2 is a sectional view showing an embodiment of this invention.
The figure is a horizontal sectional view of a movable cover showing another embodiment of this invention. 1... Water cooling mold, 4... Moving cover, 5... Winch, 6... Electrode, 7... Ingot, 8... Molten slag, 40... Inlet, 60... Insulating outer skin.

Claims (1)

[Scope of utility model registration request] In an electroslag melting furnace in which a non-consumable electrode faces into a water-cooled mold from above, a cylindrical movable cover is inserted into the water-cooled mold from above so as to be movable up and down relative to the water-cooled mold. The non-consumable electrode vertically penetrates inside the wall, the lower end thereof protrudes below the movable cover, and the outer periphery of the electrode is coated with an insulator to be electrically insulated from the movable cover. Electroslag melting furnace.