JPH02217782A - Dc arc furnace - Google Patents

Abstract

PURPOSE:To shorten the smelting time of a metallic material and unify the temperature distribution of molten metal by a method wherein a switch is operated to select one piece or more than two pieces of electrodes among the electrodes arranged for a furnace while a DC voltage is impressed between the selected electrode and another one piece of the electrode, inserted into the furnace from the upper part of the furnace to generate an arc. CONSTITUTION:The terminals 61-65 of anodes 41-45 are arranged on a cemicircle about the terminal 66 of a DC power source 31 on a changeover switch 51. When metallic material is charged into an arc furnace 21 and the changeover switch 51 is rotated reciprocally by energizing the DC power source 31, the connected contact of the switch 51 is changed continuously and, accordingly, the anode, on which the DC voltage is impressed, is changed while repeating the cycle of anode 45 anode, 45,44 anode 44...anode 41 anode 41, 42 anode 42...anode 45 continuously with respect to a cathode 11 while the direction of arc, generated in accordance with the continuous changes, is changed continuously. As a result, the smelting time of the metallic material may be shortened as a whole and the metallic material may be molten uniformly.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a DC arc furnace.

Arc furnaces are widely used for melting metal materials. Arc furnaces can be divided into AC arc furnaces and DC arc furnaces depending on the voltage applied between two electrodes, but in recent years, compared to AC arc furnaces, electric power consumption and electrode consumption are smaller,
In addition, there is little need to replace the electrodes due to wear and tear, and there is no interference with radio waves due to flicker.

Direct current arc furnaces are attracting attention.

The present invention provides a direct current arc furnace, in particular, when applying a direct current voltage between both electrodes, one of two or more electrodes is selected.
The present invention relates to a DC arc furnace in which the direction of the generated arc can be changed by arbitrarily selecting one or more electrodes.

<Prior art and its problems> Conventionally, in a DC arc furnace, one cathode connected to a DC power source is charged into the furnace from the upper part of the furnace, and a single cathode connected to the DC power source is charged into the furnace from the upper part of the furnace. One or more anodes are placed at the bottom of the furnace, and a DC voltage is constantly applied between the two electrodes, and the generated arc melts the metal material loaded into the furnace. is used.

However, in a conventional DC arc furnace in which a DC voltage is constantly applied between two electrodes, the direction of the generated arc is constant, so the overall melting time of the metal material 4 is relatively long, and the molten metal There is a problem that the temperature distribution tends to become uneven.

<Problems to be Solved by the Invention and Means for Solving the Problems> The present invention provides an improved DC arc furnace that solves the conventional problems as described above.

However, the present invention...

In a DC arc furnace that melts metal materials with an arc generated by applying a DC voltage between both electrodes, one electrode connected to a DC power source is inserted into the furnace from the top of the furnace. Further, two or more electrodes connected to the DC power source via a changeover switch are disposed at the bottom or side of the furnace, and by operating the changeover switch, one of the two or more electrodes is connected to the DC power source. Or arbitrarily select two or more and charge the selected electrode and the above 1 into the furnace from the upper part of the furnace.
The present invention relates to a DC arc furnace that is configured to apply a DC voltage between two electrodes.

Function> The DC arc furnace according to the present invention allows one or more electrodes to be arbitrarily selected from two or more electrodes arranged at the bottom or side of the furnace by operating a changeover switch. death,
An arc is generated by applying a DC voltage between the selected electrode and one electrode inserted into the furnace from the top of the furnace.Therefore, operating the selector switch → selecting the electrode → applying DC voltage →By repeatedly generating an arc continuously or intermittently, and by arbitrarily changing the direction of the generated arc, the overall melting time of the metal material can be shortened, and the temperature of the molten metal can be kept uniform. It is something to do.

Hereinafter, the configuration of the present invention will be explained in more detail based on the drawings.

<Example> FIG. 1 is an overall schematic view (partially sectional view) showing an example of the present invention. One cathode 11 is charged into the furnace from the upper part of the arc furnace 21. The cathode 11 is connected to a DC power source 31. Further, a total of five anodes 41 to 45 are arranged at the bottom or side of the arc furnace 21, and the anodes 41 to 4 are disposed at the bottom or side of the arc furnace 21.
5 is connected to the DC power supply 31 via the changeover switch 51.
It is continued. In the changeover switch 51, terminals 61 to 65 of the anodes 41 to 45 are arranged on a semicircle around a terminal 66 of the DC power supply 31, and a sector-shaped contact piece 71 is pivotally supported on the terminal 66. The contact piece 71 is configured to repeat semicircular reciprocating rotation manually or electrically.
In the drawing, the contact piece 71 is in contact with the terminal 65, so that the terminal 65 is a contact point and the terminals 64 to 61 are non-contact points. However, when the contact piece 71 is rotated slightly counterclockwise in a semicircular shape, the contact piece 71 is in contact with the terminal 65. 71 is in contact with the terminal 65 and the terminal 64, so the terminal 65 and the terminal 64 are the contact points, and the terminals 63 to 61 are the non-contact points. Due to the semicircular reciprocating rotation of the contact piece 71, the contact points are as follows: terminal 65→terminal 85, 64→terminal 6411... terminal 61→terminal 61, 62→terminal 62... It changes continuously through repetition, so the changeover switch 51 has a series of contacts.

Metal materials are loaded into the arc furnace 21, and the DC power source 31
When the selector switch 51 is reciprocated in a semicircular manner by energizing the switch 51, the contact point changes continuously as described above, so that the anode to which the DC voltage is applied to the cathode 11 is the anode 45.
→ Anode 45.44 → Anode 44・φ・Kakeban Anode 41 → Anode 41, 42 → Anode 42・Fist * Sha → Anode 45 changes continuously by turning around, and arc generated accordingly direction changes continuously. As a result, the overall time for dissolving the metal material is shortened, and the metal material is evenly melted.

Needless to say, the drawing shows one embodiment of the present invention, and the present invention is not limited to this embodiment. and the number of their terminals is arbitrary; for example, for a total of 10 anodes, each two anodes share one terminal, and the total number of terminals is 5.
In addition, various types of changeover switches can be used, and the contacts may be changed intermittently.

<Effects of the Invention> As explained above, the present invention has the effect that the overall time for dissolving the metal material can be shortened and the metal material can be uniformly melted.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram (partially sectional view) showing one embodiment of the present invention. 11... cathode, 21... arc furnace 31...
DC power supply, 41-45... Anode 5I... Changeover switch Patent applicant: Daiichi Special Steel Co., Ltd. Patent attorney: Hiroshi Masaru Iriyama

Claims (1)

[Claims] 1. In a DC arc furnace that melts metal materials with an arc generated by applying a DC voltage between both electrodes, one electrode connected to a DC power supply is connected to the furnace from the top of the furnace. Two or more electrodes are arranged at the bottom or side of the furnace, and are charged into the furnace and connected to the DC power source via a changeover switch, and when the changeover switch is operated, the One or more of the two or more electrodes are arbitrarily selected, and a DC voltage is applied between the selected electrode and the one electrode inserted into the furnace from the upper part of the furnace. A DC arc furnace consisting of: 2. The DC arc furnace according to claim 1, wherein the changeover switch has a series of contacts.