Copper contact claw and manufacturing method thereof

Abstract

The invention relates to a copper contact jaw (1) for an electrical melting device, which can be placed on an electrode support arm (2) of the melting device and by means of which an electrode of the melting device can be electrically conductively connected to the electrode support arm (2), having a main body (4), the base body has a rear surface (5) and an opposite front surface (6), a first end face (9) and an axially opposite second end face (10), and at least one first side face (11a) and a second side face (12a); two contact surfaces (7, 8) arranged on a front surface (6) of the main body (4), which contact surfaces (7, 8) are formed mirror-symmetrically to one another and extend axially along the main body (4); and a cooling channel system having a coolant inlet (13) and a coolant outlet (14) and a plurality of cooling channels (15) extending axially and radially through the base body (4).

Description

Technical Field

[0001] The invention relates to a copper contact claw for an electrical melting device, in particular an electric arc furnace, which can be attached to an electrode support arm of the melting device and by which an electrode of the melting device can be electrically conductively connected to the electrode support arm. The invention also relates to a method for producing the copper contact claw according to the invention. Background Art

[0002] Contact claws of this type have long been known from the prior art, for example from German laid-open patent specification DE 34 43 574 A1 and German laid-open patent specification DE 10 2004 005 051 A1.

[0003] Such contact claws made of pure copper are produced by first providing a rolled or forged copper blank which is then machined by introducing holes for water cooling. Due to the dimensions of the contact claws, which can have, for example, a length of 750 mm, a width of 600 mm and a thickness of 150 mm, deep hole drilling remains a technical challenge. Therefore, larger hole diameters of at least 24 mm are now used, wherein holes are usually drilled into the contact claws on the opposite end sides so that the holes intersect in the middle. The two openings can then be closed with copper plugs in the manner of welding technology or by means of threaded screw plugs.

[0004] When welding copper, it is usually necessary to preheat the material to be welded uniformly to a temperature of around 600°C, which is very energy-consuming and time-consuming. The temperature at the location to be welded is then above 1200°C, which leads to local recrystallization of the structure and thus to a loss of the original hardness of the material acquired by the forging or rolling process. Due to the high ambient temperature in the system, sealing with threaded screw plugs or similar methods cannot be guaranteed in the long term. Summary of the invention

[0005] Against this background, the object of the present invention is to provide a copper contact claw for an electrical melting plant, in particular for an electric arc furnace, which is improved compared to the prior art, and to provide a method for producing such a copper contact claw which is improved compared to the prior art.

[0006] This object is achieved according to the invention by a copper contact claw having the features of claim 1 and by a method having the features of claim 9 .

[0007] According to the present invention, a copper contact claw that can be placed on an electrode support arm of a melting device and through which an electrode of the melting device can be conductively connected to the electrode support arm includes a base body, the base body having a rear surface that is usually close to (facing) the electrode arm and a front surface that is arranged oppositely and usually close to (facing) the electrode, a first end surface and a second end surface that is arranged axially opposite and faces the melt of the melting device in the installed state, and at least one first side surface and a second side surface; two contact surfaces arranged on the front surface of the base body, the contact surfaces are constructed in a mirror-symmetrical manner to each other and extend axially along the base body; and a cooling channel system, the cooling channel system having a coolant inlet and a coolant outlet and a plurality of cooling channels extending axially and radially through the base body.

[0008] Likewise, the method according to the invention for producing a copper contact claw provides that first a forged or rolled copper contact claw blank is provided, which comprises a base body having a rear surface and an oppositely arranged front surface, a first end face and an axially oppositely arranged second end face, at least one first side face and a second side face, and two contact surfaces arranged on the front surface of the base body, which contact surfaces are constructed mirror-symmetrically to one another and extend axially along the base body; wherein a coolant inlet, a coolant outlet and a plurality of cooling channels extending axially and radially through the base body are then introduced mechanically, preferably by means of deep hole drilling.

[0009] By means of a cooling channel system comprising a coolant inlet, a coolant outlet and a plurality of cooling channels extending axially and radially through the base body, an improved heat dissipation is achieved on the one hand due to the increased number of cooling channels. In addition, since the diameter of the cooling channels is much smaller than in the prior art, the cooling channels can be placed closer to the highly loaded (highly demanding) contact surfaces, so that the cooling effect of the cooling channels can be significantly improved. In terms of manufacturing technology, the copper contact claws according to the invention no longer require welding. This achieves on the one hand that the material does not undergo recrystallization and thus retains the microstructure formed during the forging process or rolling process, thereby ensuring a longer service life. On the other hand, no secondary machining is required and no adjustment time is required, so that the manufacturing costs can be further reduced.

[0010] The dependent claims provide further advantageous embodiments of the invention. The features listed individually in the dependent claims can be combined with one another in a technically meaningful manner and can define further embodiments of the invention. In addition, the features provided in the claims are explained and illustrated in more detail in the description and further preferred embodiments of the invention are presented.

[0011] In the context of the present invention, the term "plurality of cooling channels" is understood to mean that the cooling system comprises at least ten, preferably at least twenty, more preferably at least thirty, even more preferably at least forty, and most preferably at least fifty individual cooling channels.

[0012] The plurality of cooling channels are advantageously formed in the main body and are fluidically connected to one another, so that the cooling channels can be supplied with coolant via a single centralized coolant inlet and a single centralized coolant outlet.

[0013] According to the method according to the invention, 1 to 3 larger holes of at least 24 mm are replaced by a plurality of smaller deep holes which are fluidically connected to one another. The required cooling water quantity, for example 5000 l / h of cooling water quantity, can be ensured by means of a large number of cooling channels. In addition, the large number of cooling channels formed by the deep holes open on one side allows them to be arranged in the copper contact jaws so that the threaded screw plug which closes the opening when the copper contact jaws are used is not directly exposed to the radiant heat of the melt.

[0014] Preferably, it is provided that each cooling channel has a diameter in the range of 4.0 to 16.0 mm, more preferably in the range of 5.0 to 14.0 mm, even more preferably in the range of 6.0 to 12.0 mm, and most preferably in the range of 6.00 to 10.0 mm. In a particularly preferred embodiment variant, the diameter of each deep hole and therefore the diameter of each cooling channel is 8.0 mm.

[0015] In a further advantageous embodiment variant, it is provided that the plurality of cooling channels are formed by a plurality of cooling channel groups, which extend axially or radially through the base body of the copper contact claw. In this respect, it is particularly preferably provided that each of the plurality of cooling channel groups comprises at least two, preferably at least three, more preferably at least four or more cooling channels. In a particularly preferred embodiment variant, each of the plurality of cooling channel groups comprises four cooling channels. By combining a plurality of cooling channels into individual groups, the manufacturing process can be further simplified, since a plurality of deep holes can be produced in a single processing step.

[0016] On the other hand, the present invention also relates to an electric melting device, in particular an electric arc furnace, comprising an electrode support arm and a copper contact claw arranged on the electrode arm according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention and the technical field are explained in more detail below with reference to the accompanying drawings. It should be noted that the illustrated embodiments are not intended to limit the present invention. Specifically, unless otherwise explicitly stated, some aspects of the facts explained in the drawings can also be extracted and combined with other components and cognitions of the present specification and / or the drawings. It should be particularly noted that the drawings, in particular the dimensional ratios shown, are merely schematic. The same reference numerals represent the same objects, so the explanations of other drawings can be supplemented when necessary. The drawings show:

[0018] Figure 1a / Figure 1b A perspective view of an embodiment variant of a copper contact claw according to the invention,

[0019] Figures 2 to 6 Different cross-sectional views of the copper contact claws shown in FIG1 , and

[0020] Figure 7 Embodiment variant of the electrode limb comprising copper contact jaws. DETAILED DESCRIPTION

[0021] Figure 1a and Figure 1b Two different perspective views show variant embodiments of a copper contact claw 1 according to the invention. The copper contact claw 1 consists of forged pure copper (99.98 wt. %) and is intended for use in an electrical melting plant, for example an electric arc furnace. Such a melting plant, more precisely an electric arc furnace, may include one or more electrode support arms 2 (see Figure 7 ), copper contact claws 1 are respectively fixed at the distal ends of the electrode support arms. The electrode of the melting device, such as a graphite electrode, is conductively connected to the electrode support arm 2 through the copper contact claws 1 and the fixing member 3. Usually, the electrode (not shown) is force-transmittingly connected to the electrode support arm 2 through the fixing member 3.

[0022] As shown in Figure 1 to Figure 6 As shown, the copper contact claw 1 comprises a base body 4 having a rear surface 5 facing the electrode arm 2 and a front surface 6 arranged opposite the rear surface 5 and thus facing the electrode. In order to achieve a sufficiently good electrical contact between the electrode and the copper contact claw 1, the front surface 6 has two contact surfaces 7, 8, which each include a concave recessed portion, the contact surfaces extending axially along the base body 4 and being constructed to be mirror-symmetrical to each other. It should be pointed out that, as an alternative to the embodiment variant currently shown, the front surface 6 can also be constructed by a continuous concave surface design. In this case, the two contact surfaces 7, 8 form an integral part.

[0023] Furthermore, the base body 4 comprises a first end face 9 , a second end face 10 and in each case two side faces 11 a , 11 b , 12 a , 12 b , wherein the second end face is arranged axially opposite the first end face 9 and faces the melt in the installed state.

[0024] According to the invention, it is provided that the copper contact claw 1 comprises a cooling channel system having a coolant inlet 13 , a coolant outlet 14 and a plurality of cooling channels 15 which extend through the base body 4 in the axial direction and in the radial direction.

[0025] In the present embodiment variant, the coolant inlet 13 and the coolant outlet 14 are arranged in the upper third viewed in the axial direction and thus in a region close to the first end face 9 so that they are not directly exposed to the radiant heat of the melt during use. It can also be seen from the figure that the copper contact jaw 1 has a single and therefore concentrated coolant inlet 13 and coolant outlet 14, respectively, which are fluidically connected to a plurality of cooling channels 15.

[0026] In the embodiment variant shown, these multiple cooling channels 15 are formed by multiple individual cooling channel groups 16 to 30, which extend axially (cooling channel groups 16, 18, 20, 22, 24, 26, 28, 30) or radially (cooling channel groups 17, 19, 21, 23, 25, 27, 29) through the base body 4 and are therefore arranged alternately with each other. In the present case, each cooling channel group 16 to 30 consists of four individual cooling channels 15, wherein each of these individual cooling channels 15 is formed by an individual deep hole, which has been drilled into the base body 4 through the corresponding face 5, 9, 11a, 11b, 12a, 12b. In other words, each cooling channel 15 is formed by a deep hole open on one side, which is then closed by a threaded screw plug (not shown).

[0027] Therefore, the coolant (eg, water) introduced via the centralized coolant inlet 13 first flows through the four individual channels 15 of the first cooling channel group 16 in the direction of the second end face 10 (see Figure 2 Then, the coolant is supplied to the cooling channels 15 of the third cooling channel group 18 via the four channels 15 of the second cooling channel group 17 (see Figure 2 The coolant flows through the cooling channel toward the first end face 9 through the copper contact claw 1 (see Figure 2 Then, the coolant reaches the channel 15 of the fifth cooling channel group 20 via the four channels 15 of the fourth cooling channel group 19, and the coolant flows through the copper contact claw 1 again in the direction of the second end face 10 (see Figure 4 As shown in the arrows 34 and 35 in FIG. Figure 4 and Figure 5As can also be seen, the coolant then flows into the cooling channel 15 of the seventh cooling channel group 22 via the four channels 15 of the sixth cooling channel group 21, which are arranged centrally in the axial direction and extend in the radial direction, and the coolant flows through the copper contact claw 1 in the direction of the second end face 9 (see Figure 5 Arrow 36 and Figure 2 Then, the coolant flows from the eighth cooling channel group 23 via the four adjacent channels 15. Figure 2 The left copper contact claw half shown flows radially into the opposite right copper contact claw half (see Figure 2 As shown in the arrow 38 in the figure, the coolant flows through each cooling channel group 24 to 30 in the right copper contact claw half in the opposite direction to the left copper contact claw half. Figure 2 , Figure 3 and Figure 5 As shown by arrows 39 to 43 in FIG.

[0028] In the present embodiment variant, the copper contact claw 1 has an axial length of 750 mm, a width of 600 mm and a thickness of 150 mm. A deep hole drill with a diameter of 8.0 mm is used to produce the individual cooling channels 15, so that a minimum volume flow of 5000 L / h can be achieved through the entire cooling channel system.

[0029] Especially from Figure 1a and Figure 1b As can be seen from the illustration, all the deep holes are spaced as far as possible from the second end face 10 facing the melt during use, so that the threaded screw plugs closing the respective openings of the deep holes are not directly exposed to the radiant heat of the melt.

[0030] List of reference numerals:

[0031] 1 Copper contact claw

[0032] 2 Electrode support arm

[0033] 3 Fixing parts

[0034] 4 Matrix

[0035] 5 Rear surface

[0036] 6 Front surface

[0037] 7 Contact surface

[0038] 8 Contact surface

[0039] 9 First end face

[0040] 10 Second end surface

[0041] 11a Side

[0042] 11b Side

[0043] 12a Side

[0044] 12b Side

[0045] 13 Coolant inlet

[0046] 14 Coolant outlet

[0047] 15 cooling channels

[0048] 16 axial cooling channel groups

[0049] 17 radial cooling channel group

[0050] 18 axial cooling channel groups

[0051] 19 radial cooling channel groups

[0052] 20 axial cooling channel groups

[0053] 21 radial cooling channel group

[0054] 22 axial cooling channel groups

[0055] 23 radial cooling channel group

[0056] 24 axial cooling channel groups

[0057] 25 radial cooling channel groups

[0058] 26 axial cooling channel groups

[0059] 27 radial cooling channel groups

[0060] 28 axial cooling channel groups

[0061] 29 radial cooling channel groups

[0062] 30 axial cooling channel group

[0063] 31 Arrows

[0064] 32 Arrows

[0065] 33 Arrows

[0066] 34 Arrows

[0067] 35 Arrows

[0068] 36 Arrows

[0069] 37 Arrows

[0070] 38 Arrows

[0071] 39 Arrows

[0072] 40 Arrows

[0073] 41 Arrow

[0074] 42 Arrow

[0075] 43 arrows.

Claims

1. A copper contact claw (1) for an electric melting device, the copper contact claw preferably being used in an electric melting device, the copper contact claw being attachable to an electrode support arm (2) of the melting device and being able to electrically connect an electrode of the melting device to the electrode support arm (2) via the copper contact claw, the copper contact claw comprising: A base body (4), the base body having a rear surface (5) and an oppositely arranged front surface (6), a first end surface (9) and an axially oppositely arranged second end surface (10), and at least one first side surface (11a) and a second side surface (12a); Two contact surfaces (7, 8) arranged on the front surface (6) of the base body (4), the contact surfaces being constructed mirror-symmetrically to each other and extending axially along the base body (4); It is characterized in that The copper contact claw has a cooling channel system with a coolant inlet (13) and a coolant outlet (14) as well as a plurality of cooling channels (15) extending axially and radially through the base body (4).

2. The copper contact claw (1) according to claim 1, wherein: Each of the cooling channels (15) has a diameter in the range of 4.0 to 16.0 mm, preferably in the range of 5.0 to 14.0 mm, more preferably in the range of 6.0 to 12.0 mm.

3. The copper contact claw (1) according to claim 1 or 2, wherein: Each of the cooling channels (15) is formed by a deep hole which is open on one side.

4. The copper contact claw (1) according to any one of the preceding claims, wherein: The plurality of cooling channels (15) are formed by a plurality of cooling channel groups (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30), which extend axially or radially through the base body (4) of the copper contact claw (1).

5. The copper contact claw (1) according to claim 4, wherein: Each cooling channel group of the plurality of cooling channel groups (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30) comprises at least two, preferably at least three cooling channels (15).

6. The copper contact claw (1) according to claim 4 or 5, wherein: Each cooling channel (15) of each cooling channel group (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30) is formed by a deep hole.

7. The copper contact claw (1) according to any one of the preceding claims, wherein: The coolant inlet (13) and the coolant outlet (14) are arranged in the rear surface (5) and at an end close to the first end surface (9).

8. Electrical melting device, in particular an electric arc furnace, comprising an electrode support arm (2) and a copper contact claw (1) according to any one of the preceding claims, arranged on the electrode arm (2).

9. Method for producing a copper contact claw (1), preferably a copper contact claw (1) according to any one of the preceding claims 1 to 7, wherein: First, a forged or rolled copper contact claw blank is provided, which comprises a base body (4), the base body having a rear surface (5) and an oppositely arranged front surface (6), a first end face (9) and an axially oppositely arranged second end face (10), at least one first side face (11a) and a second side face (12a), and two contact surfaces (7, 8) arranged on the front surface (6) of the base body (4), the contact surfaces being constructed in a mirror-symmetrical manner to each other and extending axially along the base body (4); then, a coolant inlet (13), a coolant outlet (14) and a plurality of cooling channels (15) extending axially and radially through the base body (4) are mechanically introduced, preferably by deep hole drilling.

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