FR2750537A1 - DEVICE FOR ELECTRICALLY CONNECTING AN ELECTRODE, PARTICULARLY A METALLURGICAL OVEN, WITH RETURN MEANS - Google Patents

Abstract

The invention discloses a device for electrically connecting an electrode, in particular of a metallurgical furnace, comprising a multiplicity of contact plates (3) arranged at the periphery of an electrode, an annulus (5) arranged at the periphery of the said contact plates and comprising a multiplicity of interconnected annulus elements (6), and a multiplicity of thrusting means (9) operating respectively between an annulus element and a contact plate to bring this plate to bear against the electrode, further comprising a multiplicity of complementary return means (28, 40) connected respectively to a contact plate (3) and to an annulus element (6) and which operate in the direction that separates the contact plate from the electrode.

Description

"Device for electrical connection of an electrode
in particular a metallurgical furnace. with recall means "
The present invention relates to an improvement to the electrical connection devices of an electrode, in particular of an electrode of a metallurgical furnace, which comprises a multiplicity of contact plates arranged on the periphery of the electrode, a crown disposed at the periphery of said contact plates and comprising a multiplicity of crown elements connected together, as well as a multiplicity of thrust means acting respectively between a crown element and a contact plate to apply this plate against the electrode.

 According to an object of the invention, the aforementioned connection device further comprises a multiplicity of complementary return means which respectively are connected to a contact plate and to a crown and act in the direction which separates the contact plate from the electrode.

 According to other objects of the invention, different alternative embodiments of said additional return means are proposed.

 According to other objects of the invention, different means of protection and electrical insulation of the device are proposed.

 The electrical connection device of an electrode preferably comprises a multiplicity of complementary return means which respectively are connected to a contact plate and to a crown element and act in the direction which separates the contact plate from the electrode.

 According to the invention, said complementary return means may advantageously comprise at least one spring.

 According to the invention, said additional return means can advantageously comprise at least one actuator.

 According to the invention, said pushing means preferably comprise a movable part bearing against the contact plate, said complementary return means comprising connecting means for connecting this movable part and acting in the direction which separates the latter from the electrode.

 According to the invention, said pushing means preferably comprise a first part fixed to the crown element, a second movable part (21) bearing against the contact plate and pressure means (26) which act in the direction which separates these parts, said complementary return means comprising connecting means for connecting said second part and the contact plate and acting in the direction which brings said first and second parts together.

 According to a variant of the invention, the aforementioned connecting means comprise at least one radial rod which has a first shoulder bearing against an outer face of said movable part and a second shoulder bearing against an inner face of the contact plate.

 According to the invention, said second shoulder can advantageously comprise at least one attachment portion and the contact plate can advantageously comprise at least one access slot to said interior face, such as in a first angular position of said rod, said attachment portion of said second shoulder can be engaged through said slot then, by rotation of said rod, brought into abutment against the abovementioned inner face of the contact plate.

 According to the invention, the contact surface between said second shoulder and said contact plate is preferably spherical or cylindrical.

 According to the invention, the contact surface between the aforementioned movable part of said pushing means and said contact plate is preferably spherical or cylindrical, said connecting means passing through this contact surface.

 According to an alternative embodiment of the invention, the first and second abovementioned parts of said thrust means one carry a cage and the other a rod which penetrates into this cage, a return spring being interposed between a shoulder of end of said cage and an end shoulder of this rod.

 According to an alternative embodiment of the invention, a double-acting cylinder, the parts of which movable relative to one another are respectively connected to the contact plate and to the crown element, constitutes at least partially said thrust means and said complementary return means.

 According to the invention, means forming a stop, limiting the movement of the contact plate in the direction of the crown element under the effect of said additional return means, can advantageously be provided.

 According to the invention, electrical insulation means interposed between said thrust means and, respectively, the contact plates and the crown elements can advantageously be provided.

 According to the invention, protective means can advantageously extend at least partially between the contact plates and the crown elements and be carried by at least one of the latter, these protective means at least partially isolating said means. thrust from the outside.

 According to the invention, said protection means can advantageously comprise deflectors.

 According to the invention, said protection means can advantageously comprise at least one bellows.

 According to the invention, said protection means preferably carry, on their surfaces, electrical insulation means.

 According to the invention, electrical insulation means interposed between said protection means and the contact plates and / or the crown elements can advantageously be provided.

The present invention will be better understood from the study of various electrical connection devices for an electrode, described by way of nonlimiting examples and illustrated by the drawing in which;
- Figure 1 shows a vertical section of an electrical connection device according to the invention arranged around an electrode
- Figure 2 shows a bottom view of the device of Figure 1;
- Figure 3 shows a first axial section of a first thrust means according to the invention, according to III-III of Figure 5
- Figure 4 shows another axial section of the thrust means of Figure 3, according to IX-IX of Figure 5
- Figure 5 shows a radial section of the pushing means of Figure 3, according to VV of this Figure 3
- Figure 6 shows a radial section of the thrust means of Figure 3, according to VI-VI of this Figure 3
- Figure 7 shows, in enlarged axial section, a detail of the aforementioned thrust means
- Figure 8 shows an axial section of second thrust means according to the invention
- And Figure 9 shows an enlarged radial section, along VIII Vffi of Figure 8, of a detail of these thrust means.

 Referring to Figures 1 and 2, we see that there is shown an electrical connection device, generally identified by the reference 1, a cylindrical electrode 2 arranged vertically.

 This device 1 comprises, in the example, six solid contact plates 3 in the form of arcs of a circle, spaced in the peripheral direction, which are arranged around the electrode 2 and which are respectively suspended from bars 4 which are 'extend up.

 The device 1 further comprises a crown 5 which remotely surrounds the contact plates 3 and which is composed of six massive elements of crown 6 in the form of arcs of a circle, the peripheral ends of which have yokes engaged in one another and connected by vertical axes 7, these crown elements 6 being suspended from bars 8 which extend upwards.

 The device 1 also comprises six pushing means 9 which are arranged between the contact plates 3 and the crown elements 6 and which act substantially radially to the electrode 2.

 Furthermore, the contact plates 3 are supplied with electrical energy by electrical conduits or sheaths 10 which extend upwards and which have a central channel 11 connected to an external circuit for circulation of a cooling fluid, such as of water, and connected to internal channels 12 of the contact plates 3.

 The crown elements 6 have lower channels 13 in which a cooling fluid such as water can flow, connected to inlet-outlet conduits 14 which extend upwards.

 Referring to FIGS. 3 to 7, a thrust means will now be described, generally identified by the reference 15, arranged between the contact plates 3 and the crown elements 6 and equipped with complementary return means, generally identified by reference 16.

 The thrust means 15 comprise an outer plate 17 in the form of a disc fixed against an inner face 18 of a crown element 6 by means of two diametrically opposed screws 19 and two other special screws 20 diametrically opposite, located at 900 relative to the screws 19, an inner plate 21 in the form of a disc, the central part of which bears against a support plate 22 fixed against an outer face 23 of a contact plate 3 by means of screws 24, thus than a metal bellows 25 which connects the peripheral edges of the outer and inner plates 17 and 21, so as to delimit a chamber 26.

 The special screws 20 have an axial passage 27 which makes it possible to connect the internal channels 13 of the crown element 6 to the chamber 26, so that the latter can be pressurized by the pressure of the cooling fluid circulating in these channels 13.

 Thus, the pressure of the fluid in the chamber 26 acts in the direction which makes it possible to apply the contact plate against the peripheral face of the electrode 2 by moving the inner plate 21 away from the inner plate 21 and by performing an extension. bellows 25.

 The contact surface 27 between the inner plate 21 of the pushing means 15 and the support plate 22 carried by the contact plate 3 is spherical or cylindrical, so that one can slide relative to the other so to adapt the pressure forces and to position themselves well in relation to each other.

 The complementary return means 16 comprise a rod 28 which extends axially to the chamber 26, through the outer plate 17, the chamber 26, the inner plate 21 and the support plate 22, freely in this last, and which thus has an external end 28a accessible externally to the crown element 6 and an internal end 28b which extends in a recess 29 formed between the support plate 22 and the contact plate 3.

 The rod 28 has a first shoulder 30 which bears on the end of a projecting part 30a of the inner plate 21, in the chamber 26. As can be seen more particularly in FIG. 7, the end 28b of the rod 28 is screwed into a washer 31 which is disposed in the aforementioned recess 29, this washer being carried freely by the support plate 22 by means of two diametrically opposed screws 32, the washer 31 being in abutment against the plate support 32 by a spherical or cylindrical support surface 31a.

 Thus, the rod 28, thanks to its shoulder 30 and to the washer 31 which constitutes a second shoulder, makes it possible to connect the internal plate 21 of the pressure means 15 to the support plate 22 carried by the contact plate 3.

 Furthermore, the annular seals 33 and 34 are arranged between the rod 28 and the outer and inner plates 17 and 21.

 The additional return means 16 further comprise three return members 35 which are arranged inside the chamber 26, at 1200 relative to one another.

 These return members comprise rods 36 which are carried, by screwing, by the internal plate 21 and which extend towards the external plate 17, as well as cages or stirrups 37 which are carried by the external plate 17 and which extend towards the inner plate 21, around and at a distance from the rods 36. The ends of the rods 36 and the cages 37 have shoulders 38 and 39, between which are arranged return springs 40.

 The return springs 40 act in the direction which makes it possible to move the internal plate 21 towards the external plate 17, thus separating the contact plate 3 from the electrode 2. Thus, when the contact pressure exerted by the fluid introduced into the chamber 26 disappears, the springs 40 act to separate the contact plates 3 from the electrode 2, by exerting a certain compression of the bellows 25.

 Of course, the pressure of the fluid in the chamber 26 causing the bearing forces of the contact plates 3 on the electrode 2 must be sufficient to act against the return springs 40.

 For the installation of the thrust means 15 and additional return means 16, one can proceed as follows.

 The thrust means 15 fitted with the return members 35 and the rod 28 are mounted against the inner face 18 of the crown element 6a. The crown element 6 is brought closer to the contact plate 3 by engaging the inner end 28b of the rod 28 through the support plate 22 carried by the contact plate 3, until the inner plate 21 is brought in contact with the support plate 22. Then, with a tool capable of cooperating with the outer end 28a of the rod 28, the latter is rotated so as to screw its inner end 28b into the connecting washer 31 in order to connect the inner plate 21 with the contact plate 3 as described above, and therefore the movable member of the return means 16, constituted by the movable member of the thrust means 15, to the contact plate 3.

 Furthermore, the connection device 1 is equipped with means of protection and electrical insulation generally identified by the reference 41.

 These protective means 41 comprise a layer 42 of an electrically insulating material, interposed between the crown element 6 and the inner plate 17 and a layer 43 of an electrically insulating material, disposed between the support plate 22 and the contact 3 and between the fixing screws 24 and the support plate 22.

 The protection means 41 further comprise a cylindrical cage 44 which remotely surrounds the bellows 25 and which is fixed against the inner face 18 of the crown element 6 by screws 45, bearing on the aforementioned layer 42. This cylindrical cage 44 carries on its inner face a layer 46 of an electrically insulating material.

 The protection means 41 further comprise a cylindrical outer cage 47 which remotely surrounds the cylindrical cage 44 and which is connected to the latter by means of a bellows 48. The inner face of the cylindrical cage 47 carries a layer 49 made of an insulating material and its outer face carries a layer 50 of an insulating material. The cage 47 also has a peripheral rim 51 which bears against the external face of the contact plate by means of a layer 52 of an insulating material, under the effect of the elasticity of the bellows 48.

 In addition, between the cylindrical cage 44 and the cylindrical cage 47 is disposed an annular seal of round section 53, obstructing the access between these cages but allowing the displacement of one relative to the other axially to the thrust means 15 .

 Thus, the thrust means 15 are, to a certain extent, protected against the penetration of materials between the contact plate 3 and the crown element 6 and against any electric arcs which could occur between them.

 Referring to Figures 8 and 9, we will now describe other thrust means and other additional return means which, in this example, are constituted by a double-acting cylinder generally identified by the reference 54, arranged between a contact plate 3a and a crown element 6a.

 This jack 54 comprises a box 55 which has a cylindrical peripheral wall 56, an outer end plate 57 which bears against the underside 58 of the crown element 6a and which has a projecting part 59 which extends through a passage 60 of the crown element 6 formed at the bottom of an external recess 61 of this crown element 6a, the end of the projecting part 59 of the plate 57 carrying a fixing nut 62 which abuts at the bottom of the recess 61. The box 55 further comprises an inner end plate 53 located at a distance from an outer face 64 of the contact plate 3a.

 The cylinder 54 further comprises, in the box 55, a piston 65 which carries a projecting part 66 which extends through the outer plate 57 and through its projecting part 59 and a projecting part 67 which s 'extends through the inner plate 63, the piston 65 determining in the box 55 a thrust chamber 68 located on the side of the outer end plate 57 and a return chamber 69 located on the side of the inner end plate 63. On these chambers 68 and 69 are connected conduits 70 and 71 for supplying and returning actuating fluid, connected to at least one source of pressurized fluid.

 The end of the projecting part 67 of the piston 65, situated outside the box 65 and on the side of the contact plate 3a, carries an intermediate plate 72 which comes to bear against a support plate 73 fixed against the outer face 64 of the contact plate 3a as in the previous example, these plates 72 and 73 having a spherical or cylindrical contact surface 74 as in the previous example.

 Furthermore, the piston 65 and its projecting parts 66 and 67 as well as the intermediate plate 72 and the support plate 73 are crossed, freely, by a rod 75 which has an outer end 75a which extends into the recess outside 61 of the crown element 6a and which has an inner end 75b which extends into a recess 76 in the contact plate 3a equivalent to the recess 29 in the previous example.

 The end 75b of the rod 75 carries a crosspiece 77 which extends in the recess 76 and which is in contact with the support plate 73, by a spherical or cylindrical surface 77a as in the previous example. This support plate 73 has diametrically opposite slots 78 and 79 for the introduction of the cross-member 77.

 The outer end 75a of the rod 75 carries, in the recess 61 of the crown element 6a, a nut 80 which is in contact with the outer end of the projecting part 59 of the piston 65, so that 'thus the intermediate plate 72 carried by the piston 65 is fixed to the support plate 73 carried by the contact plate 3a.

 The jack 54 operates in the following manner.

 The supply of a pressurized fluid into the thrust chamber 68 causes a displacement of the piston 65 in the direction of the electrode 2, thus displacing the contact plate 3a in the direction which applies it against the external wall of the electrode 2.

 On the other hand, the supply of a pressurized fluid into the return chamber 69 of the jack 54 causes a displacement of the piston 65 towards the outside, thus spreading the contact plate 3a from the electrode 2, the stroke of the plate contact 3a in this direction being limited by the fact that the piston 65 comes into contact with the end plate 57 of the box 65, thus constituting a stop.

 For installation, you can proceed as follows.

 The cylinder 54 is fixed on the crown element 6a having equipped it with the rod 75. The crown element 6a is brought closer to the contact plate 3a by engaging the end 75b of the rod 75 through the support plate 73, by passing its transverse bar 77 through the slots 78 and 79 of this support plate 73. When the plate 72 of the jack 54 comes into contact with the support plate 73, the rod is rotated 75 with a tool capable of cooperating with its end 75a so as to arrange the crosspiece 77 behind the support plate 73. Then, the nut 80 carried by the outer end 75a of the rod 75 is tightened so as to apply the cross-member 77 against the support plate 73 in the recess 76 and thus connect the contact plate 3a with the movable member of the jack 54 formed by its piston 65.

Finally, the recess 61 of the crown element 6a is obstructed by a removable plug 87.

 As in the previous example, the thrust means 54 are equipped with protection and electrical insulation means generally identified by the reference 81.

 These protection means 81 include, as in the previous example, a layer 82 of an electrically insulating material interposed between the support plate 73 and the contact plate 3a.

They also comprise a layer 83 of an insulating material interposed between the end plate 57, the projecting part 59 and the nut 62 of the box 55.

 The protective means 81 also comprise a bellows 84 which on the one hand is fixed to the periphery of the support plate 73 and which on the other hand abuts against the face of the box 55 facing inwards, as well as a cylindrical cage 85 also fixed to the periphery of the support plate 73, this cylindrical cage 85 being provided externally with a layer 86 of an electrically insulating material 86.

Claims (18)

 1. Device for the electrical connection of an electrode, in particular an electrode of a metallurgical furnace, comprising a multiplicity of contact plates (3) arranged at the periphery of the electrode (2), a ring (5) disposed at the periphery of said contact plates and comprising a multiplicity of crown elements (6) interconnected, as well as a multiplicity of thrust means (9) acting respectively between a crown element and a contact plate for applying this plate against the electrode, characterized in that it further comprises a multiplicity of complementary return means (16) which respectively are connected to a contact plate (3) and to a crown element (6) and act in the direction that spreads the electrode contact plate.  2. Device according to claim 1, characterized in that said complementary return means comprise at least one spring (40).  3. Device according to claim 1, characterized in that said additional return means comprise at least one cylinder (69).  4. Device according to any one of the preceding claims, characterized in that the said pushing means comprise a movable part (21; 65, 72) bearing against the contact plate, the said complementary return means comprising connecting means (28; 75) to connect this movable part and acting in the direction which separates the latter from the electrode.  5. Device according to any one of the preceding claims, characterized in that the said pushing means comprise a first part (17) fixed to the crown element, a second movable part (21) bearing against the contact plate (3) and pressure means (26) which act in the direction which separates these parts, said complementary return means comprising connection means (28) for connecting said second part (21) and the contact plate (3) and acting in the direction which brings said first and second parts (17, 21) closer together.  6. Device according to one of claims 4 and 5, characterized in that the aforementioned connecting means comprise at least one radial rod (28; 75) which has a first shoulder (30; 80) bearing against an outer face of said movable part and a second shoulder bearing against an inner face (31a; 77a) of the contact plate.  7. Device according to claim 6, characterized in that said second shoulder comprises at least one hooking part (77) and the contact plate comprises at least one slot (78) for access to said inner face, such that in a first angular position of said rod (75), said hooking part (77) of said second shoulder can be engaged through said slot then, by rotation of said rod, brought into abutment against the abovementioned inner face of the plate of contact.  8. Device according to one of claims 6 and 7, characterized in that the contact surface (31a) between said second shoulder and said contact plate is spherical or cylindrical.  9. Device according to any one of claims 4 to 8, characterized in that the contact surface (27, 74) between the aforementioned movable part of said pushing means and said contact plate is spherical or cylindrical, said means of connection passing through this contact surface.  10. Device according to any one of claims 4 to 9, characterized in that the aforementioned first and second parts of said pushing means carry one cage (37) and the other a rod (36) which enters this cage, a return spring (40) being interposed between an end shoulder of said cage and an end shoulder of this rod.  11. Device according to any one of the preceding claims, characterized in that a double-acting cylinder (54), the parts (55, 65) of which are movable relative to each other are respectively connected to the contact plate and the crown element, at least partially constitutes said thrust means and said complementary return means.  12. Device according to any one of the preceding claims, characterized in that it comprises means forming a stop (57, 65) limiting the movement of the contact plate in the direction of the crown element under the effect of said additional means of recall.  13. Device according to any one of the preceding claims, characterized in that it comprises electrical insulation means (42, 43) interposed between said thrust means (15) and, respectively, the contact plates (3 ) and the crown elements (6).  14. Device according to any one of the preceding claims, characterized in that it comprises protective means (44, 47) which respectively extend at least partially between the contact plates and the crown elements and are worn by at least one of the latter, these protective means at least partially isolating said thrust means (15) from the outside.  15. Device according to claim 14, characterized in that said protection means comprise deflectors.  16. Device according to claim 14, characterized in that said protection means comprise at least one bellows (48).  17. Device according to any one of claims 14 to 16, characterized in that said protective means carry on their surfaces means of electrical insulation (46, 50).  18. Device according to any one of claims 14 to 17, characterized in that it comprises electrical isolation means interposed between said protection means and the contact plates and / or the crown elements.