JPS6347038Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to an improvement of the clamped portion of a water-cooled electrode used in an arc furnace for steelmaking.

<Prior art> Generally, in an electric furnace, about three graphite electrodes 1 are connected in series, as shown schematically in FIG. This is a semi-permanent electrode that is used in place of the upper 1/2 to 2/3 of the entire length of the electrode 1. The water-cooled electrode 2 is
It is a cylindrical body made of copper with a cooling water circulation passage inside, a cooling water supply and drainage pipe at the upper end, and a screw hole for connecting a graphite electrode at the lower end. In the figure, 3 is an electrode support arm, and 4 is a back-up spring of the electrode clamp device.

In the conventional method shown in FIG. 3a, when the graphite electrode 1 becomes worn out and shortened, it is added to the upper end, moved downward, and then gripped again with the grip section for use. With water-cooled electrodes that have recently come into use, only the lower graphite electrode 1 is replaced, and the upper end of the water-cooled electrode remains in place.

Further, the structure of the clamp device that holds the electrode is approximately the same as that of the conventional method, as shown in an enlarged view in FIG. That is, as shown in the figure, the inner surface of the back-up spring 4 is provided with receiving-side conductive liners 5, 5 formed into three segment blocks and a push-side conductive liner 6. It is biased by a strong spring 7 and includes an air cylinder 8 for opening when attaching and detaching the electrode. The above liner 5, 5,
Since water-cooled electrodes 6 have come into use, graphite segment blocks 5a, 5a, 6a have been interposed between the conventional copper liners 5, 5, 6 and the water-cooled electrodes. The means for installing the graphite segment blocks 5a, 5a, 6a are as follows:
For example, the blocks 5a, 5a, 6a are clamped with their lower ends supported by a refractory ring provided on the lower side. Note that the conductive liners 5, 5, and 6 are connected to a power transmission main pipe so that power is transmitted to the electrodes through this.

<Problem that the invention aims to solve> Since water-cooled electrodes have been used, the clamping device has to keep gripping the same part and is strong enough to support the weight of the electrode. The soft water-cooled electrode began to become deformed (dented). Due to this deformation, when the liner is replaced with a new one, the liner and the water-cooled electrode do not come into close contact with each other. As a result, sparks occur due to energization, creating further unevenness, resulting in a problem of shortening the lifespan of the water-cooled electrode and the liner.

Additionally, if the water-cooled electrode is to be attached to or removed from the clamping device for some reason, there is no suitable means for holding the graphite segment block while the clamping device is in the open state, and conventional holding means will prevent the block from falling off. There was a problem that could cause a problem.

The purpose of this invention is to prevent the water-cooled electrode from deforming, thereby extending the life of the water-cooled electrode and the liner, and to prevent danger during repair work by eliminating the risk of graphite segment blocks falling off. do.

<Means for Solving the Problems> The means of this invention provides a water-cooled electrode for an electric furnace in which the clamped portion of the electrode is clamped by a clamping device via a copper liner provided on the clamping device side. A copper cylindrical part has a thick wall and has a cooling water circulation passage therein, and graphite is attached to the outer surface of the copper cylindrical part at a position corresponding to the inside of each of the copper liners with set screws. It is characterized by comprising a segment block.

<Function> According to the means of this invention, the copper cylindrical part of the clamped part of the water-cooled electrode is formed with a thick wall, so that it does not pass through the screw hole for attaching the graphite segment block with a set screw. Since it can be easily drilled into the copper cylindrical part, the graphite segment block can be reliably attached with the set screw without any trouble, and it can be prevented from falling off.

In addition, since the copper cylindrical portion is formed with a thick wall, it will not be deformed by clamping, so even if the copper liner or graphite segment block is replaced, they will stick together and maintain good conductivity. is always ensured.

<Example> In FIGS. 1 and 2, 10 is a water-cooled electrode, and the clamped portion is formed by attaching a graphite segment block 11 to the upper part. The part to which the segment block 11 is attached is a copper cylindrical part 12, which has a thick peripheral wall, and a stainless steel pipe 14 with an outer diameter matching the inner hole 13 is inserted through the inner hole to form a cooling water supply path. year,
Three holes 15 are bored in the peripheral wall in parallel with the cooling water supply passage, and these holes serve as cooling water discharge passages. The cross-sectional area of the three holes 15 serving as cooling water discharge passages is set to be approximately equal to the cross-sectional area of the inner hole of the stainless steel pipe 14.

The graphite segment blocks 11 correspond to the positions of the copper liners 5, 5, 6 in the existing clamping device (substantially the same as shown in FIG. 4).
It is attached to the outer surface of the copper cylindrical part 12 with a set screw 16. The position of the screw hole into which the set screw 16 is screwed is formed away from the position of the hole 15. In the clamping device, the same parts as shown in FIG. 4 are designated by the same reference numerals and their explanation will be omitted.

In FIG. 1, 17 is a protective refractory for a water-cooled electrode, and 18 is a screw hole for connecting a graphite electrode.

This water-cooled electrode 10 is clamped by a clamping device shown by phantom lines in the figure, so that copper conductive liners 5, 5, and 6 are attached to graphite segment blocks 11, respectively.
It is tightened and supported in a circumscribed positional relationship, and is used in this state.

In the above embodiment, the hole 15 was bored in the thickness of the peripheral wall of the copper cylindrical part 12 to serve as a cooling water discharge path.
In some cases, the entire outer periphery of the cooling water supply pipe may be made into a cavity and used as a cooling water discharge path, as in the conventional system. However, in that case, the copper cylindrical part 1
Make the thickness of 2 as thick as possible.

<Effects of the invention> According to this invention, there is no deformation of the clamped part of the water-cooled electrode or wear due to sparks, and the water-cooled electrode can be used semi-permanently. At the same time, it is possible to reliably prevent the graphite segment blocks from falling off. The effect is that repair work etc. can be carried out safely and efficiently.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical sectional side view of an embodiment of this invention.
Figure 2 is a sectional view taken along line A-A in Figure 1, Figure 3a is a schematic side view of a conventional graphite electrode, Figure 3b is a schematic side view of a conventional water-cooled electrode, and Figure 4 is a typical electrode clamp. FIG. 2 is a cross-sectional plan view along an electrode support arm schematically showing the device. 5, 6...Copper liner, 10...Water-cooled electrode, 1
1...Graphite segment block, 12...Copper cylindrical part, 14...Stainless steel pipe (cooling water supply path),
15... Hole (cooling water discharge path), 16... Set screw.

Claims (1)

[Scope of utility model registration request] In a water-cooled electrode for an electric furnace in which a clamped part of the electrode is clamped by a clamping device via a copper liner provided on the clamping device side, the clamped part has a cooling water circulation passage inside and is formed with a thick wall. An electric furnace comprising a copper cylindrical part and a graphite segment block attached by a set screw to a position corresponding to the inside of each of the copper liners on the outer surface of the copper cylindrical part. water-cooled electrode.