ZA200503012B - Device for electrical connection of an electrode, in particular of a metallurgical furnace electrode - Google Patents

Description

i r NE 3 i WO 2004/036958 PCT/FR2003/002948

Device for electrical connection of an electrode, in particular of a metallurgical furnace electrode

The present invention relates toc an improvement tO electrical connection aevices fcr ccnnecting an electroae, in particular a metailurgica: f.rnace electrode. 30 Docume. DCA 28 20 42° dincinnog an elertrical connection device for an electrode that comprises two rings surrounding an electrode, these peing located at a certain distance apart and connected to a single current source via a junction box.

The object of the present invention is mainly to improve the conditions for thermal and/or electrical coupling to an electrode, in particular when the latter is a Soderberg electrode which comprises a cylindrical sheet in which granular blocks undergo, through the effect of electrical currents, a treatment and a transformation into liquid and/or pasty form before entering into reaction with the material treated in the furnace.

The electrical connection device for connecting an cloctrode according to the invention may advantageously comprise at least one contact ring placed around the electrode and comprising a multiplicity of contact plates, retention means placed around said contact ring and applying said contact plates against the periphery of tne electrode, and electrical connection means for supplying electrical power to said contact plates.

According to the present invention, said contact plates include means that define, aiong the longitudinal direction of the electrode, at least two annular zones which are in contact with the periphery of the

- Co, electrode and in which the conditions Zor electrical and/or thermal coupling with the electrode are different.

According To the present invention, the Means defining at least one cf said zcnes may advantageously De formed by z+ _east cne _aver made cI at least one material, said layer being deposited cr addea te —he plates.

Acccrding to the present invention, the means defining bald euues way advantageously bo formed, respectively, by layers of materials that are deposited or added on the plates and have different electrical and/or thermal characteristics.

According to the present invention, the means defining at least one of said zones may advantageously be formed by annular means made of at least one insulating material, said means being placed in a channel for the circulation of a cooling fluid made in each of said plates and extending over at least one portion of this channel.

According to the present invention, said annular means may advantageously comprise at least two parts placed along two corresponding portions of the parallel branches of a U-shaped circulation channel.

According to the present invention, sald annular means may advantageously be formed by at least one added annular insert.

According to the present invention, sald annular means may advantageously be formed by at least one layer made of at least one insulating material deposited against the wall of said cocling channel.

According to the present invention, said retention means may advantageously comprise at least one retention ring placed around said contact ring and comprising a multiplicity of ring elements connected together, and a multiplicity of thrust means that act, respectively, between a ring element and a contact plate in crder To app.y thls contact plate against the peripnery cf the electrode.

Accerding “to the present invention, said means for supplying electrical power to ~he electrode may advantageously comprise means for generating at least vii Loipperaturs gradisrt along the 1Anmitidinal direction of the electrode.

According to the present invention, the device could advantageously comprise at least first and second contact rings that are placed around the electrode, these being spaced apart longitudinally and comprising, respectively: a multiplicity of first and second contact plates; retention means that are placed around said contact rings and apply sald contact plates against the periphery of the electrode; and a multiplicity of electrical connection means for supplying electrical power to the contact plates of said contact rings, respectively.

According to the present invention, said retention means could advantageously be comprise at least first and sceccond retention rings placed respectively around said contact rings and comprising respectively a multiplicity of first and second ring elements connected together respectively; and a multiplicity of thrust means that act respectively between a ring element and a contact plate in order to apply this contact plate against the electrode.

According to the present invention, the electrical : connection means and/or the suspension means for the contact plates of said second contact ring and/or the suspension means for the ring elements of said second

. Co retention ring and/or the means for delivering and returning a fluid for cooling the contact plates of said second contact ring and/or the means for controlling the thrust means associated with said secend ring elements and with sald seccnd contact plates pass between said first contact ring and sald first retention rinc.

The present inventicn will be more ciearly understood on studying the electrical connection devices for commecting a motallurgianl furnace electrode, these being described by way of nonlimiting examples and illustrated by the drawing in which: - figure 1 shows a side view of an electrical connection device for connecting an electrode according to the present invention; - figure 2 shows a bottom view of a connection device of figure 1; - figure 3 shows a top view of a peripheral portion of the connection device of figure 1: - figure 4 shows a vertical radial section, on

ITI-III, of the portion shown in this figure 3, in its central part; - figure 5 shows a vertical section, on IV-1IV, of the portion shown in this figure 3, slightly offset relative to the section III-TII; - figure 6 shows a vertical section, on V-V, of the portion shown in this figure 3, offset relative to the aforementioned sections; - figure 7 shows a horizontal section of a peripheral portion of the aforementioned connection device, passing between ‘ts upper part and its lower parc; - figure 8 shows a side view of an internal portion of the aforementioned connection device; - figure 9 shows a perspective view of a contact plate for another electrical connection device according to the invention; - figure 10 shows a perspective view of a contact

. Ce p_ate of another electrical connection device according to the invention; and - figure 11 shows a vertical section of the plate of figure 10.

The device . comprises an upper set or first set 3 and a lower set or second set 4 cof electrical connections that are placed around the electrode 2 anc are separated from one another longitudinally to the electrode, but at a short distance apart.

The electrical connection device shown in figures 1 to 8, which is identified in general by the reference 1, is intended to supply electrical power to a vertical cylindrical electrode 2 of the furnace.

The upper set 3 comprises a first contact ring 5 which is made up, in the example, from six solid contact plates 6 in the form of circular arcs at a certain distance apart, generally made of copper, a first retention ring 7, which is placed around and at a certain distance from the contact ring 5 and which is made up, in the example, from six solid ring elements 8 in the form of circular arcs, the ends of which have projecting parts 8a and 8b that engage in one another and are connected together via vertical spindles 9, and also six thrust means 10 which are placed between the contact plates 6 and the ring elements 8, respectively, in the central part of the latter. in a corresponding fashion, the lower set 4 comprises a sccend contact ring 11 which is made up from six solid contact plates 12 ir the form of circular arcs, a second retention ring 13 placed around and at a certain distance from the contact ring 11 and made up from six solid ring elements 14 in the form of a circular arcs, +he peripheral ends of which nave proiecting parts l4a and 14b that are engaged in one another and connected +ogether via vertical spindles 15, and also six thrust

. Ce means .6 placed between the contact plates 12 and the ring elements, respectively, substantially in their central part.

The upper € and _ower 1Z contact piates and he upper 8 and lower .4 ring elements are respectively aligned along the direction of the axis cI the electrode 2.

The upper contact plates 6 and the upper ring elements 8 are supported by the lower end of a suspension bar 17 aiid of a suspension bar 19, rospoctively, via vnkes 19 and 20 fastened on their upper face, near their middle in “he peripheral: direction.

The lower contact plates 12 are supported by the lower ends of a pair of suspension bars 21 and 22, respectively, via yokes 23 and 24 that are fastened against the outer face of the contact plates 12, between these plates and the ring elements 14. The suspension bars 21 and 22 extend upward symmetrically with respect to the radial plane of the contact plates 12 and pass, through the upper set 3, between “he upper contact plates 6 and the upper ring elements 8, on either side of the thrust means 10 and on the side facing the upper contact plates 6.

Fastened to the inner faces of the peripheral end parts cf the lower ring elements 14 and symmetrically with respect to their radial plane is a pair of suspension arms 25 and 26 which extend upward and pass between the upper contact plates 6 and the upper ring elements 8, through the upper set 3. Above this set 3, the suspension arms 25 and 26 are supported by means of yokes 29 and 30, via the ends of a pair of suspension bars 27 and 28 that extend upward.

Connected to the upper part of the outer faces ci the upper contact plates 6 are electrical current ducts or conduits 31 that are angled upward and pass between the

. C4 upper contact plates 6 ard the upper ring elements 38, and then extend upward, in order also to be connected to an electrical current source.

Connectec to the upper parc cs the outer face cf the ower contact plates 12 are electrica. current ducts Or condui~s 32 that are anc.ed, in order tc pass between the lower cortact plates 12 and the lower ring elements 14, and then extend upward passing between the upper

PRY) contact plates 6 and the upper ring e.ements 8, through

Uli uppe. 35% 2, =o bo aloe connected To An electrical power source.

The electrical conduits or ducts 31 and 32 have respective axial channels 33 and 34 that are connected to circuits of internal channels 35 and 36 that are made inside the upper contact plate 6 and the lower contact plates 12, respectively, these circuits of internal channels 35 and 36 also being connected to external conduits 37 and 38 in such a way that it is thus possible to make a coolant, such as water coming from an external circuit, circulate inside the plates © and 12. The conduits 37 are connected against the outer face of the upper contact plates 36 and are angled so as to be directed upward, and the conduits 38 are connected against the outer faces of the lower contact plates 12 and are angled upward and extend upward passing between the npper contact plates 6 and the upper ring elements 8, through the upper set 3.

The upper ring elements 8 have a circuit of internal channels 29, the ends of which are connected to conduits 4C and 41 +that extend upward from the upper face of these upper ring elements 8 and are also connected to an external circuit for circulation of a coolant, such as water.

The lower ring elements 14 have, in their lower part and prciecting inward, ower rims 42 from which

. Ce conduits 43 and 44 extend upward, said conduits passing between the lower contact plates 12 and the lower ring elements 14 and then between the upper contact plates 6 and the upper ring elements 8, through the set 3. The conduits 43 and 44 are connected TO a CIrCult of internal channels 45 that are made inside the lower ring elements 14 and are &.SO connected Tc an external circui+ for circulaticr cf a coolant, such as water. 0 In the example shown, the thrust means 10 and 16 comprise Liuid chasers pounded peoripheratly bv metal bellows 46 and 47, these chambers being connected with their respective internal channels 39 and 45 of the upper and lower ring elements 8 and 14 sc as to be subjected to the pressure of the fluid circulating in these channels, this pressure generating the radial forces that make the upper contact plates 6 and the lower contact plates 12 bear, respectively, against the outer wall of the electrode 2.

In another example, the thrust means 10 and 12 may comprise hnydraulic cylinders. The connection members for connecting these cylinders to a pressurized £luid source will then be placed so as to extend through spaces separating the contact plates 6 and 12 and the ring elements 8 and 14, respectively.

Of course, the various members described above and connected to the contact plates 6 and 12 and to the ring elements 8 and 14 may be configured differently in order to be adapted to the spaces separating them, respectively.

Thanks to the arrangements described, the external environment of the retention rings 7 and 13 is free. he electrical connection device 1 that has Just Deen described produces, along the longitudinal direction of the e.ectrode, two annular zones 3a and 4a formed by

Cg the contact rings 5 and 11 in which the conditions for electrical and thermal coupling with the electrode 2 that are generated are the same or different depending on the electroae treatment requirements, these conditions essentially depending on the size cf the plates, the electrical power supp.y currents and the cocliant temperatures.

In particular, it 1s possible to obtain higher and longitudinally better distributed density of the ~leactrianl anvronte flowing thrangh the electrode 2 and over a greater length of the latter, thus making it possible to 1mprove the treatments “hat this electrode undergoes owing to the electrical currents that flow through it.

Figure 9 shows a contact plate 50 of a contact ring 51, said contact ring not being shown entirely and comprising, for example, six identical contact plates, 290 this contact ring 51 forming part of a single electrical connection device similar to one of the electrical connection sets described above and placed around the electrode 2.

The inner face 52 in contact with an electrode 2 of each contact plate 50, generally made of copper, of the contact ring 51 is provided with an upper deposited layer 53 and with an intermediate deposited layer 54, the lower part 55 of each plate 50 being bare.

Thus, the contact ring 51 has an upper annular zone 56, an intermediate annular zone 57 and a lower annular zone 58, these being in contact with the electrode 2 and placed along the longitudinal direction of the latter, in which the conditions for electrical and/or thermal coupling with the electrode may be adapted according to the constituent materials of the layers 53 and 54 and to the height of these layers, for the purpose of obtaining a desired treatment of the electrode 2.

If it is desired essentially to reduce the thermal conduction between the plate 50 and the electrode 2 in one of the annular zcnes 56 and 57, or tc reduce it by different amounts in two zones, the layer 53 and/or the layer 54 may comprise a copper/phosphorus-based alloy or amalgam.

If it is desired essentially toc increase the electrical conduction bhatuaan the plate 50 and the electrode 2 in one of the annular zones 56 and 57, or to increase it by the same amount or by aifferent amounts in the two zones, the layer 53 and/or the layer 54 may comprise a silver-based alloy or amalgam.

If it is desired essentially to reduce the electrical conduction between the plate 50 and the electrode 2 in one of the annular zones 56 and 57, or to reduce it by the same amount or by different amounts in the two zones, the layer 53 and/or the layer 54 may comprise an alloy or amalgam based on copper and zinc, chromium or aluminum.

The layers will preferably have a thickness of between 0.1 and 0.3 mm and may be deposited by plasma spraying or by electroplating.

In one particular arrangement, the upper zone 56 might be formed so as essentially to reduce the thermal conduction and the intermediate zone 57 might be formed sc as To easentially increase the electrical conduction.

Depending on the embodiment, the plate 50 might comprise only one of the layers 53 or 54, or mcre than two layers, or it might also 1ncliude a layer on: the lower part of its face 52.

an

Figures 10 and 11 show a contact plate 60 for a contact ring 62, not shown entirely and comprising, for example, six identical contact plates. As in the example described with reference tO figure 9, this contact ring 6. may form part cf a single electrical ccrnectior device similar to one of the electrical cormection secs described abcve and placed around ~he e_ectrode 2. 0 The contact plate 60 has a U-shaped interna. channel 62 curending oo an to have 2 horizontal hranch 63 formed in its lower part and two vertical branches 64 formed respectively between one guarter and cne third of the way along its circumference.

The vertica. branches 64 of the channel 62 have, in their upper part, a larger diameter in which a tubular cylindrical insert 65 is placed, the thermal conductivity of the insert being less than that of the constitutent material of the plate 60, generally made of copper. In one example, the insert could be made of a ceramic ard could extend over the upper three- quarters of the height of the vertical branches 64.

The added inserts 65 make it possible to reduce, in the upper part of the contact plate 60, the heat transfer from this plate 60 into the fluid circulating in the channel &2, in such a way that the contact ring 61 has, longitudinally along the electrode 2, two annular zones 66 and 67 in which the conditions for thermal coupling with the electrode 2 are different, in fact generating 2 temperature gradient along the longitudinal direction cf the electrode.

Depending on the embodiment, the channel 62 might have several distributed inserts, in order to form several zones along the ongitudinal direction of the electrode 2, and these zones might be determined not by added inserts but by layers deposited against the wall of the channel 62, made of a material that is a poorer thermal conductor than that constituting the plates 6C.

Furthermore, the arrangements described with reference to figures 9 to 1. could be applied tc one cf the aforementicred sets of =the device 1 described with reference tc figures 1 To B, or tc both cf them.

The present invention is not limited tc the examples described above. In particular, the various embodiments described sould he ~amhined, altagether ar partly, depending on the electrode treatment requirements.

Furthermore, the retention ana bearing means fer the contact plates could be different. Many other variants are possible without departing from the scope defined by the appended claims.

Claims (18)

1%% Filing - 13 - Amended on 21/02/03 CLAIMS

1. Device for electrically connecting an electrode, particularly an electrode of a metallurgical furnace, characterized in that it comprises means for supplying the electrode with electrical power, comprising means (6, 12, 53, 54, 65) determining, in the longitudinal direction of the electrode, at least two annular zones (3a, 4a, 56, 57, B58], AA, A7) in contact with the periphery of the electrode and in which the conditions of electrical and/or thermal coupling with this electrode differ.

2. Device for electrically connecting an electrode, particularly an electrode of a metallurgical furnace, particularly according to Claim 1, characterized in that it comprises: - at least a first and a second contact ring (5, 11) arranged around the electrode (2), spaced apart longitudinally and respectively comprising a multitude of first and second contact shoes (6, 12), - holding means (7, 13) arranged around the said contact rings and pressing the said contact shoes against the periphery of the electrode, - and a multitude of electrical-connection means (31, 32) for supplying the respective contact shoes of the said contact rings with electrical power.

3. Device according to Claim 2, characterized in that the said holding means comprise: - at least a first and a second holding ring (7, 13) these being respectively arranged around the said contact rings and respectively comprising a multitude of first and second ring elements (8, 14) respectively joined together,

1% Filing - 14 - Amended on 21/02/03 - and a multitude of thrusting means (10, 16) acting respectively between a ring element and a contact shoe to press this contact shoe against the electrode.

4. Device according to Claim 3, characterized in that the means (32) of electrical connection of the contact shoes of the said second contact ring pass between the said first contact ring and the said first holding ring.

5. Device according to one of Claims 3 and 4, characterized in that the suspending means (21) for suspending the contact shoes of the said second contact ring pass between the said first contact ring and the said first holding ring.

6. Device according to any one of Claims 2 to 5, characterized in that the suspending means (25) for suspending the ring elements of the said second holding ring pass between the said first contact ring and the said first holding ring.

7. Device according to any one of Claims 2 to 6, characterized in that the supply and return means (34) for supplying and returning a cooling fluid for the contact shoes of the said second contact ring pass between the said first contact ring and the said first holding ring.

8. Device according to any one of Claims .2 to 7, characterized in that the supply and return means (43) for supplying and returning a cooling fluid for the ring elements of the said second holding ring pass between the said first contact ring and the said first holding ring.

1%°¢ Filing - 15 - Amended on 21/02/03

9. Device according to any one of Claims 2 to 8, characterized in that the means for controlling the thrusting means (16) associated with the said second ring elements and with the said second contact shoes pass between the said first contact ring and the said first holding ring.

10. Device for electrically connecting an electrode, pallicularly an clectrode nf Aa metallurgical furnace, particularly according to Claim 1, characterized in that it comprises: - at least one contact ring (51) arranged around the electrode (), comprising a multitude of contact shoes (50), - holding means (7, 13) arranged around the said contact ring and pressing the said contact shoes against the periphery of the electrode, - and a multitude of electrical-connection means (31) for supplying the said contact shoes with electrical power, - the said contact shoes (50) comprising means (53, 65) determining, in the longitudinal direction of the electrode, at least two annular zones (56, 66) in contact with the periphery of the electrode and in which the conditions of electrical and/or thermal conpling with this electrode differ.

11. Device according to Claim 10, characterized in that the said holding means comprise: - at least one holding ring (7) arranged around the said contact ring and comprising a multitude of ring elements joined together, - and a multitude of thrusting means (10) acting respectively between a ring element and a contact shoe to press this contact shoe against the periphery of the electrode.

15% Filing - 16 - Amended on 21/02/03

12. Device according to one of Claims 10 and 11, characterized in that the means determining at least one of the said zones are formed of a layer (53) of a material deposited on or attached to the shoes.

13. Device according to one of Claims 10 and 11, characterized in that the means determining the said zones are formed respectively of layers (53, 54) of matcriale deponited on or attached to the shoes and having different electrical and/or thermal properties.

14. Device according to one of Claims 10 and 11, characterized in that the means determining at least one of the said zones are formed by annular means (65) made of an insulating material arranged in a cooling fluid circulation duct formed in each of the said shoes and extending over at least a portion of this duct.

15. Device according to Claim 14, characterized in that the said annular means (65) comprise at least two parts arranged along two corresponding portions of the parallel branches of a U-shaped circulation duct.

16. Device according to one of Claims 14 and 15, characterized in that the said annular means are formed of at least one attached annular insert (65).

17. Device according to one of Claims 14 and 15, characterized in that the said annular means are formed of at least one layer of an insulating material deposited against the wall of the said cooling duct.

18. Device for electrically connecting an electrode, particularly an electrode of a metallurgical furnace, particularly according to Claim 1, characterized in that it comprises means for supplying the electrode with electrical power, the means comprising means (53,

1°* Filing - 17 - Amended on 21/02/03 54, 65) allowing at least one temperature gradient to be generated along the longitudinal direction of the electrode.