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EP0515249A1 - Partial sealing device between the inside and the outside of an arc furnace - Google Patents

Partial sealing device between the inside and the outside of an arc furnace Download PDF

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Publication number
EP0515249A1
EP0515249A1 EP92401323A EP92401323A EP0515249A1 EP 0515249 A1 EP0515249 A1 EP 0515249A1 EP 92401323 A EP92401323 A EP 92401323A EP 92401323 A EP92401323 A EP 92401323A EP 0515249 A1 EP0515249 A1 EP 0515249A1
Authority
EP
European Patent Office
Prior art keywords
hollow element
electrode
opening
furnace
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92401323A
Other languages
German (de)
French (fr)
Inventor
Robert Adam
Thierry Bernet
Jean-Dominique Marchal
Daniel Pernet
Raoul Roth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Unimetal SA
Original Assignee
Unimetal SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unimetal SA filed Critical Unimetal SA
Publication of EP0515249A1 publication Critical patent/EP0515249A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0073—Seals
    • F27D99/0075—Gas curtain seals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B1/00—Shaft or like vertical or substantially vertical furnaces
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/12—Arrangements for cooling, sealing or protecting electrodes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces heated electrically, with or without any other source of heat
    • F27B3/085—Arc furnaces

Definitions

  • the present invention relates to a device ensuring improved partial sealing between an electrode of an electric arc furnace and the roof of the furnace.
  • Electric arc furnaces used in particular in the steel industry, have a vault provided with passages each crossed by an electrode.
  • the electrodes are mounted to be displaceable longitudinally in the passages.
  • the electrodes being relatively fragile and subjected to uncontrolled transverse vibrations, the walls delimiting the passages are relatively distant from the external surface of the associated electrode to avoid any contact between the electrode and said walls, contact which deteriorates the electrode.
  • Such a spacing between the walls of the passage and the electrode constitutes an important area of communication between the interior of the furnace and the ambient atmosphere.
  • a device ensuring the protection of the electrodes of an electric arc furnace and limiting the gas exchange between the interior and the exterior of the furnace, is for example described in the Utility Certificate FR - 2 360 858.
  • the present invention aims to provide a device ensuring a partial seal between the inside and the outside of an electric arc furnace, the structure of which is simple and which is easy to implement.
  • the present invention relates to a device for reducing gas exchange between the inside and the outside of an arc furnace comprising a vault having at least one opening, an electrode axially passing through the opening, a passage delimited between the wall of the opening and the electrode, characterized in that it comprises a hollow element placed on a horizontal flat external surface of the furnace perpendicular to the axis of the electrode and constituting the external end of the opening, the hollow element surrounding the electrode with an annular clearance determined and able to move freely on said outer surface.
  • Figure 1 there is shown the upper part of the roof 2 of an electric arc furnace of the tilting type, commonly used in the steel industry.
  • the vault 2 has an opening 4 with a vertical axis X-X delimited by a part of the vault forming a vault 6 having a flat horizontal upper face 8, forming the outer end face of the opening 4.
  • the electrode 10 is mounted so as to be able to move axially by means known per se, to ensure correct operation of the furnace.
  • the diameter of the outer surface 12 of the electrode 10 is significantly smaller than the diameter of the opening 4, and with the latter delimits a relatively large annular passage 14.
  • the annular passage 14 must be such that when the electrode 12 is subjected to radial vibrations, the electrode does not come into contact with the wall delimiting the opening 4, which would damage it or even break it.
  • the annular passage 14 being relatively large allows the flow of a high gas flow between the interior 16 and the exterior 18 of the oven, flow which it is necessary to reduce to ensure the proper functioning of the oven.
  • the oven is equipped with a partial sealing device which includes an annular hollow element 20.
  • the annular hollow element 20 is placed in freely sliding support on the upper face 8 of the roof, coaxially with the electrode 10, with between it and the element 20 an annular clearance 22 reduced.
  • the hollow element 20 comprises a sleeve 21 directed towards the interior 16 of the furnace, and delimiting around the electrode 10 an annular space of dimension substantially equal to the annular clearance 22 and intended to increase the pressure losses during the passage of gases to the outside of the furnace.
  • the hollow element 20 comprises two radial annular plates 26 and 28 which are parallel and axially spaced apart from each other, the externally radial peripheries of the plates 26 and 28 being connected by a sleeve 30 of axis XX.
  • the internally radial peripheries 32 and 34 of the plates 26 and 28 respectively have the same diameter, the latter being slightly greater than the diameter of the external surface 12 of the electrode 10, and significantly smaller than that of the opening 4 of the furnace.
  • the space existing between the plates 26 and 28 comprises radial partitions 36 regularly distributed on the internal surface 38 of the sleeve 30.
  • the partitions 36 are fixed by welding to the internal surface 38 of the sleeve 30.
  • partitions 36 can also be welded on one of the plates 26 or 28, or on both.
  • the internally radial end 40 of the partitions 36 is located between the plates 26 and 28, that is to say axially set back towards the sleeve 30 relative to the peripheries 32 and 34 of the plates 26 and 28 respectively, so that the partitions are not damaged in the event of contact between the hollow element and the electrode in the absence of the stops 24 or during the handling of the elements prior to their establishment.
  • the partitions 36 thus delimit compartments 42 open on their face intended to be opposite the electrode 10.
  • the compartments 42 thus constitute a baffle creating pressure losses in the flow of gases entering or leaving the oven, which, added to the small annular clearance 22, will considerably reduce the gas exchange between the interior 16 and the exterior. 18 from the oven.
  • the hollow element 20 being of light construction and simply placed on the surface 8, will slide on the latter when the electrode 10 is subjected to radial vibrations.
  • the gas contained in the hollow element 20 and the annular space 22 is compressed in the direction of the radial vibration of the electrode and repels the hollow element 20, so that the annular space 22 remains substantially constant, thus avoiding contact of the electrode 10 with the hollow element 20.
  • the hollow element 20 is made, preferably of metal, for example of non-magnetic stainless steel so as to limit the creation within it of eddy currents due to the intense magnetic fields created in the vicinity of the electrodes. These eddy currents would heat it up and lead to its rapid deterioration.
  • FIGS. 4 and 5 show another embodiment of a hollow element 20, in which the externally radial periphery of the latter is open and opens into an annular ring 50.
  • the annular crown 50 consists of two annular plates 52 and 54 arranged in the extension annular plates 26 and 28 respectively, the externally radial periphery of the plates 52 and 54 being closed by a cylindrical wall 56, coaxial with the hollow element 20.
  • the annular plates 52 and 54 of the crown may have come in one piece with the plates 26 and 28 respectively of the hollow element 20.
  • the cylindrical wall 56 is pierced with an orifice 58 connected to a pipe 60 for supplying gas under pressure.
  • This gas can therefore circulate in the compartments in the direction of the electrode 10. Its role is to improve the insulation between the oven and the outside air, and to cool the hollow element 20.
  • the gas can be blown directly into each or at least several of the compartments 42 by nozzles passing through the sleeve 30.
  • the pressurized gas is a neutral gas.
  • the partitions 36 of the hollow element 20 are profiled so as to constitute blades, for directing the neutral gas entering the ring 50, through the compartments 42, so such that these gas flows are inclined on the axis XX along the arrow F.
  • the partitions 36 can also be straight as in the example previously described.
  • partitions profiled in blades can also be used when gas is not blown into the hollow element 20. They offer a larger contact surface than straight partitions and therefore create more pressure drop .
  • FIGs 6 and 7 there is shown the arrangement of a hollow element 20 on an oven, the opening through which extends the electrode 10 is constituted on the one hand by an orifice 62 of the roof 6 and on the other hand by an annular plate 64.
  • the annular plate 64 is arranged parallel to the outer surface 8 of the roof top 6 and separated from the latter.
  • the annular plate 64 has an internal diameter substantially equal to the diameter of the orifice 62, and its periphery is fixed to the oven using a sleeve 66 of axis X-X.
  • the annular plate 64, the sleeve 66, and the wall of the furnace delimit an area into which gas can be blown under pressure.
  • the hollow element 20 is placed on the external face 8 of the roof 6.
  • the hollow element 20 is placed on the outer surface 70 of the annular plate 64.
  • the hollow element 20 according to the invention makes it possible to significantly reduce the communication between the interior and the exterior of the oven, between which a relative seal is thus ensured.
  • the gas exchanges were reduced using a hollow element, arranged according to FIGS. 1 and 2, the diameter of the internally radial periphery (32, 34) is 622 mm.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)

Abstract

The device, according to the invention, for partial sealing between the inside (16) and the outside (18) of an electric arc furnace containing a vault (2) possessing at least one opening (4), an electrode (10) passing axially through the opening (4), a relatively sizeable passage (14) existing between the wall of the opening (4) and the electrode (10), includes a hollow element (20) placed on a horizontal plane outside surface of the furnace perpendicular to the axis (X-X) of the electrode (10) and constituting the outside end of the opening, the hollow element surrounding the electrode with an annular clearance (22). When the furnace is of the tilting type, the device includes stops (24) limiting the movement of the hollow element (20) during the tilting of the furnace. <IMAGE>

Description

La présente invention concerne un dispositif assurant une étanchéité partielle améliorée entre une électrode d'un four électrique à arc et la voûte du four.The present invention relates to a device ensuring improved partial sealing between an electrode of an electric arc furnace and the roof of the furnace.

Les fours électriques à arc, utilisés notamment dans la sidérurgie, comportent une voûte pourvue de passages traversés chacun par une électrode.Electric arc furnaces, used in particular in the steel industry, have a vault provided with passages each crossed by an electrode.

Pour le bon fonctionnement du four les électrodes sont montées déplacables longitudinalement dans les passages.For the proper functioning of the oven, the electrodes are mounted to be displaceable longitudinally in the passages.

Les électrodes étant relativement fragiles et soumises à des vibrations transversales incontrôlées, les parois délimitant les passages sont relativement éloignées de la surface extérieure de l'électrode associée pour éviter tout contact entre l'électrode et lesdites parois, contact qui détériore l'électrode.The electrodes being relatively fragile and subjected to uncontrolled transverse vibrations, the walls delimiting the passages are relatively distant from the external surface of the associated electrode to avoid any contact between the electrode and said walls, contact which deteriorates the electrode.

Un tel espacement entre les parois du passage et l'électrode constitue une zone de communication importante entre l'intérieur du four et l'atmosphère ambiante.Such a spacing between the walls of the passage and the electrode constitutes an important area of communication between the interior of the furnace and the ambient atmosphere.

Il s'avère qu'une telle communication est néfaste.It turns out that such communication is harmful.

En effet, lorsque le four est en surpression par rapport à l'atmosphère, les gaz contenus dans le four s'échappent à travers la zone de communication. Lorsqu'au contraire le four est en dépression par rapport à l'atmosphère, de l'air pénètre dans le four. Lorsque ces échanges entre l'intérieur et l'extérieur du four sont importants, ils représentent une gêne importante pour le bon fonctionnement du four.In fact, when the oven is overpressure relative to the atmosphere, the gases contained in the oven escape through the communication area. When, on the contrary, the oven is in depression with respect to the atmosphere, air enters the oven. When these exchanges between the inside and the outside of the oven are significant, they represent a significant hindrance for the proper functioning of the oven.

C'est pourquoi différents dispositifs ayant pour but de réduire ces échanges ont été étudiés.This is why different devices aimed at reducing these exchanges have been studied.

Il faut noter que des dispositifs assurant une étanchéité totale par contact avec l'électrode ne peuvent être utilisés car ils entraineraient une détérioration rapide de cette dernière, donc des coûts élevés, lorsque l'électrode est soumise à des vibrations radiales inhérentes au passage d'un courant électrique de forte intensité dans l'électrode.It should be noted that devices ensuring total tightness by contact with the electrode cannot be used because they would cause rapid deterioration of the latter, therefore high costs, when the electrode is subjected to inherent radial vibrations. when a high intensity electric current passes through the electrode.

Un dispositif assurant la protection des électrodes d'un four électrique à arc et limitant les échanges gazeux entre l'intérieur et l'extérieur du four, est par exemple décrit dans le Certificat d'utilité FR - 2 360 858.A device ensuring the protection of the electrodes of an electric arc furnace and limiting the gas exchange between the interior and the exterior of the furnace, is for example described in the Utility Certificate FR - 2 360 858.

Ce dispositif de protection comprend :

  • une boîte à eau circulaire fixée sur la voûte du four autour de l'électrode,
  • une boîte à gaz constituée par un compartiment supérieur, solidaire de la boîte à eau et comportant une arrivée de gaz et des orifices d'échappement du gaz qui sont situés dans la partie supérieure de la boîte à gaz,
  • des pièces mobiles en forme de secteur d'arc posées sur la paroi supérieure de la boîte à gaz et coopérant entre elles pour former une couronne entourant l'électrode, chaque pièce comportant à sa base un évidement formant une chambre dans laquelle se répand le gaz, et un conduit latéral raccordé à l'évidement et débouchant latéralement en regard de l'électrode pour diriger vers celle-ci un courant de gaz.
This protection device includes:
  • a circular water box fixed on the roof of the oven around the electrode,
  • a gas box constituted by an upper compartment, integral with the water box and comprising a gas inlet and gas exhaust orifices which are located in the upper part of the gas box,
  • moving parts in the form of an arc sector placed on the upper wall of the gas box and cooperating with each other to form a ring surrounding the electrode, each part having at its base a recess forming a chamber in which the gas is spread , and a lateral duct connected to the recess and opening laterally opposite the electrode to direct a current of gas towards the latter.

Il s'avère qu'un tel dispositif est relativement complexe et difficile à mettre en oeuvre.It turns out that such a device is relatively complex and difficult to implement.

Pour remédier à ces inconvénients, la présente invention a pour but de fournir un dispositif assurant une étanchéité partielle entre l'intérieur et l'extérieur d'un four électrique à arc, dont la structure soit simple et qui soit facile à mettre en oeuvre.To remedy these drawbacks, the present invention aims to provide a device ensuring a partial seal between the inside and the outside of an electric arc furnace, the structure of which is simple and which is easy to implement.

A cet effet la présente invention a pour objet un dispositif de réduction d'échange gazeux entre l'intérieur et l'extérieur d'un four à arc comportant une voûte possédant au moins une ouverture, une électrode traversant axialement l'ouverture, un passage délimité entre la paroi de l'ouverture et l'électrode, caractérisé en ce qu'il comporte un élément creux posé sur une surface extérieure plate horizontale du four perpendiculaire à l'axe de l'électrode et constituant l'extrémité extérieure de l'ouverture, l'élément creux entourant l'électrode avec un jeu annulaire déterminé et pouvant se déplacer librement sur ladite surface extérieure.To this end, the present invention relates to a device for reducing gas exchange between the inside and the outside of an arc furnace comprising a vault having at least one opening, an electrode axially passing through the opening, a passage delimited between the wall of the opening and the electrode, characterized in that it comprises a hollow element placed on a horizontal flat external surface of the furnace perpendicular to the axis of the electrode and constituting the external end of the opening, the hollow element surrounding the electrode with an annular clearance determined and able to move freely on said outer surface.

Selon d'autres caractéristiques :

  • Lorsque le dispositif est utilisé sur un four basculant, il comporte des butées limitant le déplacement de l'élément creux sur ladite surface extérieure lors du basculement du four, pour éviter le contact entre l'élément creux et la surface extérieure de l'électrode.
  • L'élément creux comporte une face ouverte située en vis-à-vis de l'électrode.
  • L'élément creux comporte des compartiments séparés par des cloisons sensiblement radiales et ayant une face ouverte située en vis-à-vis de l'électrode.
  • Les cloisons sont angulairement réparties, de préférence de manière régulière à l'intérieur du corps creux.
  • Les cloisons comportent une extrémité intérieure radiale écartée de la face ouverte du corps creux en direction de la périphérie extérieure du corps creux.
  • Les cloisons possèdent un profil en forme d'aube.
  • L'élément creux possède une périphérie extérieure ouverte mettant les compartiments en communication avec une couronne creuse alimentée en gaz sous pression.
  • Les parois latérales de la couronne sont venues de matière avec les parois latérales de l'élément creux.
  • L'ouverture est délimitée par un orifice agencé à travers un voûtain ayant une surface extérieure horizontale plate, un manchon étant fixé coaxialement à l'orifice à l'extérieur du voûtain et comportant à son extrémité opposée au voûtain une plaque annulaire de diamètre intérieur sensiblement égal au diamètre de l'orifice pour former entre le voûtain et la plaque annulaire une zone dans laquelle peut être insufflé un gaz sous pression.
  • L'élément creux est en appui glissant sur la face extérieure de la plaque annulaire.
  • L'élément creux est en appui glissant sur le voûtain.
  • Le gaz insufflé est un gaz neutre.
According to other characteristics:
  • When the device is used on a tilting furnace, it includes stops limiting the displacement of the hollow element on said external surface during the tilting of the furnace, to avoid contact between the hollow element and the external surface of the electrode.
  • The hollow element has an open face located opposite the electrode.
  • The hollow element comprises compartments separated by substantially radial partitions and having an open face located opposite the electrode.
  • The partitions are angularly distributed, preferably regularly inside the hollow body.
  • The partitions have a radial inner end spaced from the open face of the hollow body towards the outer periphery of the hollow body.
  • The partitions have a blade-shaped profile.
  • The hollow element has an open outer periphery putting the compartments in communication with a hollow crown supplied with gas under pressure.
  • The side walls of the crown came integrally with the side walls of the hollow element.
  • The opening is delimited by an orifice arranged through a vault having a flat horizontal exterior surface, a sleeve being fixed coaxially to the orifice outside the vault and comprising at its end opposite the vault an annular plate of substantially internal diameter. equal to the diameter of the orifice to form between the roof and the plate annular an area into which gas can be blown under pressure.
  • The hollow element is in sliding contact on the outside face of the annular plate.
  • The hollow element is in sliding support on the roof.
  • The blown gas is a neutral gas.

L'invention sera mieux comprise à la lecture de la description qui va suivre faite uniquement à titre d'exemple, en référence aux dessins annexés sur lesquels :

  • La figure 1 est une vue schématique en coupe d'une ouverture de four électrique à arc équipé d'un dispositif selon une première forme de réalisation de l'invention.
  • La figure 1A est une vue analogue à la figure 1 dans laquelle le four est équipé d'une variante du dispositif selon l'invention tel que représenté sur la figure 1.
  • La figure 2 est une vue en coupe axiale, suivant II-II de la figure 3, d'un élément creux visible à plus petite échelle sur la figure 1.
  • La figure 3 est une vue de dessus de l'élément creux représenté sur la figure 2.
  • La figure 4 est une vue de dessus d'un second mode de réalisation du dispositif selon l'invention.
  • La figure 5 est une vue en coupe selon la ligne 5-5 de la figure 4.
  • La figure 6 est une vue schématique en coupe représentant un troisième mode de réalisation d'un dispositif selon l'invention sur un four électrique à arc.
  • La figure 7 est une vue analogue à la figure 6 représentant une variante d'exécution du dispositif de la figure 6.
The invention will be better understood on reading the description which follows, given solely by way of example, with reference to the appended drawings in which:
  • Figure 1 is a schematic sectional view of an opening of an electric arc furnace equipped with a device according to a first embodiment of the invention.
  • FIG. 1A is a view similar to FIG. 1 in which the oven is equipped with a variant of the device according to the invention as shown in FIG. 1.
  • FIG. 2 is a view in axial section, along II-II of FIG. 3, of a hollow element visible on a smaller scale in FIG. 1.
  • FIG. 3 is a top view of the hollow element shown in FIG. 2.
  • Figure 4 is a top view of a second embodiment of the device according to the invention.
  • Figure 5 is a sectional view along line 5-5 of Figure 4.
  • Figure 6 is a schematic sectional view showing a third embodiment of a device according to the invention on an electric arc furnace.
  • FIG. 7 is a view similar to FIG. 6 showing an alternative embodiment of the device of FIG. 6.

Sur la figure 1 on a représenté la partie supérieure de la voûte 2 d'un four électrique à arc du type basculant, couramment utilisé dans la sidérurgie.In Figure 1 there is shown the upper part of the roof 2 of an electric arc furnace of the tilting type, commonly used in the steel industry.

La voûte 2 comporte une ouverture 4 d'axe vertical X-X délimitée par une partie de la voûte formant voûtain 6 possédant une face supérieure plate horizontale 8, formant face d'extrémité extérieure de l'ouverture 4.The vault 2 has an opening 4 with a vertical axis X-X delimited by a part of the vault forming a vault 6 having a flat horizontal upper face 8, forming the outer end face of the opening 4.

Une électrode 10 ayant une surface extérieure 12 cylindrique traverse coaxialement l'ouverture 4.An electrode 10 having a cylindrical outer surface 12 coaxially crosses the opening 4.

L'électrode 10 est montée de manière à pouvoir se déplacer axialement par des moyens connus en soi, pour assurer un fonctionnement correct du four.The electrode 10 is mounted so as to be able to move axially by means known per se, to ensure correct operation of the furnace.

Le diamètre de la surface extérieure 12 de l'électrode 10 est nettement inférieur au diamètre de l'ouverture 4, et délimite avec cette dernière un passage annulaire 14 relativement important.The diameter of the outer surface 12 of the electrode 10 is significantly smaller than the diameter of the opening 4, and with the latter delimits a relatively large annular passage 14.

Le passage annulaire 14 doit être tel que lorsque l'électrode 12 est soumise à des vibrations radiales, l'électrode ne vient pas au contact de la paroi délimitant l'ouverture 4, ce qui la détériorerait ou même la briserait.The annular passage 14 must be such that when the electrode 12 is subjected to radial vibrations, the electrode does not come into contact with the wall delimiting the opening 4, which would damage it or even break it.

Le passage annulaire 14 étant relativement important permet l'écoulement d'un débit gazeux élevé entre l'intérieur 16 et l'extérieur 18 du four, écoulement qu'il est nécessaire de réduire pour assurer le bon fonctionnement du four.The annular passage 14 being relatively large allows the flow of a high gas flow between the interior 16 and the exterior 18 of the oven, flow which it is necessary to reduce to ensure the proper functioning of the oven.

A cet effet le four est équipé d'un dispositif d'étanchéité partielle qui comporte un élément creux annulaire 20.To this end, the oven is equipped with a partial sealing device which includes an annular hollow element 20.

L'élément creux annulaire 20 est posé en appui librement glissant sur la face supérieure 8 du voûtain, coaxialement à l'électrode 10, avec entre celle-ci et l'élément 20 un jeu annulaire 22 réduit.The annular hollow element 20 is placed in freely sliding support on the upper face 8 of the roof, coaxially with the electrode 10, with between it and the element 20 an annular clearance 22 reduced.

Sur la surface extérieure 8 sont fixées des butées 24, destinées à limiter le déplacement de l'élément creux 20 sur la surface 8 lors du basculement du four électrique pour en extraire le métal liquide.On the external surface 8 are fixed stops 24, intended to limit the displacement of the hollow element 20 on the surface 8 during the tilting of the electric furnace to extract the liquid metal therefrom.

On évite ainsi le contact entre l'élément creux 20 et l'électrode 10 qui, d'une part, pourrait endommager celle-ci par le cisaillement dû au choc, et d'autre part, pourrait entraîner l'amorçage d'un arc électrique entre l'élément creux et l'électrode, qui aboutirait à la destruction rapide de l'élément creux.This avoids contact between the hollow element 20 and the electrode 10 which, on the one hand, could damage the latter by the shear due to impact, and on the other hand, could cause the initiation of an arc electric between the hollow element and the electrode, which would lead to the rapid destruction of the hollow element.

En variante représentée sur la figure 1A, l'élément creux 20 comporte un manchon 21 dirigé vers l'intérieur 16 du four, et délimitant autour de l'électrode 10 un espace annulaire de dimension sensiblement égale au jeu annulaire 22 et destiné à accroître les pertes de charge lors du passage des gaz vers l'extérieur du four.As a variant shown in FIG. 1A, the hollow element 20 comprises a sleeve 21 directed towards the interior 16 of the furnace, and delimiting around the electrode 10 an annular space of dimension substantially equal to the annular clearance 22 and intended to increase the pressure losses during the passage of gases to the outside of the furnace.

En se reportant aux figures 2 et 3, on constate que l'élément creux 20 comprend deux plaques annulaires radiales 26 et 28 qui sont parallèles et écartées axialement l'une par rapport à l'autre, les périphéries extérieurement radiales des plaques 26 et 28 étant reliées par un manchon 30 d'axe X-X.Referring to Figures 2 and 3, we see that the hollow element 20 comprises two radial annular plates 26 and 28 which are parallel and axially spaced apart from each other, the externally radial peripheries of the plates 26 and 28 being connected by a sleeve 30 of axis XX.

Les périphéries intérieurement radiales 32 et 34 des plaques 26 et 28 respectivement possèdent le même diamètre, ce dernier étant légèrement supérieur au diamètre de la surface extérieure 12 de l'électrode 10, et nettement plus petit que celui de l'ouverture 4 du four.The internally radial peripheries 32 and 34 of the plates 26 and 28 respectively have the same diameter, the latter being slightly greater than the diameter of the external surface 12 of the electrode 10, and significantly smaller than that of the opening 4 of the furnace.

L'espace existant entre les plaques 26 et 28 comporte des cloisons radiales 36 régulièrement réparties à la surface intérieure 38 du manchon 30.
Les cloisons 36 sont fixées par soudage sur la surface intérieure 38 du manchon 30.The space existing between the plates 26 and 28 comprises radial partitions 36 regularly distributed on the internal surface 38 of the sleeve 30.
The partitions 36 are fixed by welding to the internal surface 38 of the sleeve 30.

Il est à noter que les cloisons 36 peuvent être également soudées sur l'une des plaques 26 ou 28, ou sur les deux.It should be noted that the partitions 36 can also be welded on one of the plates 26 or 28, or on both.

L'extrémité intérieurement radiale 40 des cloisons 36 est située entre les plaques 26 et 28, c'est-à-dire en retrait axial vers le manchon 30 par rapport aux périphéries 32 et 34 des plaques 26 et 28 respectivement, de manière à ce que les cloisons ne soient pas détériorées en cas de contact entre l'élément creux et l'électrode en l'absence des butées 24 ou lors des manipulations des éléments préalablement à leur mise en place.The internally radial end 40 of the partitions 36 is located between the plates 26 and 28, that is to say axially set back towards the sleeve 30 relative to the peripheries 32 and 34 of the plates 26 and 28 respectively, so that the partitions are not damaged in the event of contact between the hollow element and the electrode in the absence of the stops 24 or during the handling of the elements prior to their establishment.

Les cloisons 36 délimitent ainsi des compartiments 42 ouverts sur leur face destinée à être en vis-à-vis de l'électrode 10.The partitions 36 thus delimit compartments 42 open on their face intended to be opposite the electrode 10.

Les compartiments 42 constituent ainsi une chicane créant des pertes de charge dans l'écoulement des gaz entrant ou sortant du four, ce qui, ajouté au faible jeu annulaire 22, va diminuer considérablement l'échange gazeux entre l'intérieur 16 et l'extérieur 18 du four.The compartments 42 thus constitute a baffle creating pressure losses in the flow of gases entering or leaving the oven, which, added to the small annular clearance 22, will considerably reduce the gas exchange between the interior 16 and the exterior. 18 from the oven.

Par ailleurs l'élément creux 20 étant de construction légère et simplement posé sur la surface 8, va glisser sur cette dernière lorsque l'électrode 10 est soumise à des vibrations radiales.Furthermore, the hollow element 20 being of light construction and simply placed on the surface 8, will slide on the latter when the electrode 10 is subjected to radial vibrations.

En effet, le gaz contenu dans l'élément creux 20 et l'espace annulaire 22 est comprimé dans la direction de la vibration radiale de l'électrode et repousse l'élément creux 20, de manière telle que l'espace annulaire 22 reste sensiblement constant, évitant ainsi le contact de l'électrode 10 avec l'élément creux 20.Indeed, the gas contained in the hollow element 20 and the annular space 22 is compressed in the direction of the radial vibration of the electrode and repels the hollow element 20, so that the annular space 22 remains substantially constant, thus avoiding contact of the electrode 10 with the hollow element 20.

L'élément creux 20 est réalisé, de préférence en métal, par exemple en acier inoxydable amagnétique de manière à limiter la création en son sein de courants de Foucault dus aux intenses champs magnétiques créés au voisinage des électrodes. Ces courants de Foucault l'échaufferaient et conduiraient à sa rapide détérioration.The hollow element 20 is made, preferably of metal, for example of non-magnetic stainless steel so as to limit the creation within it of eddy currents due to the intense magnetic fields created in the vicinity of the electrodes. These eddy currents would heat it up and lead to its rapid deterioration.

Sur les figures 4 et 5 on a représenté un autre mode de réalisation d'un élément creux 20, dans lequel la périphérie extérieurement radiale de ce dernier est ouverte et débouche dans une couronne annulaire 50.FIGS. 4 and 5 show another embodiment of a hollow element 20, in which the externally radial periphery of the latter is open and opens into an annular ring 50.

La couronne annulaire 50 est constituée de deux plaques annulaires 52 et 54 agencées dans le prolongement des plaques annulaires 26 et 28 respectivement, la périphérie extérieurement radiale des plaques 52 et 54 étant fermée par une paroi cylindrique 56, coaxiale à l'élément creux 20.The annular crown 50 consists of two annular plates 52 and 54 arranged in the extension annular plates 26 and 28 respectively, the externally radial periphery of the plates 52 and 54 being closed by a cylindrical wall 56, coaxial with the hollow element 20.

Les plaques annulaires 52 et 54 de la couronne peuvent être venues de matière avec les plaques 26 et 28 respectivement de l'élément creux 20.The annular plates 52 and 54 of the crown may have come in one piece with the plates 26 and 28 respectively of the hollow element 20.

La paroi cylindrique 56 est percée d'un orifice 58 relié à une conduite d'alimentation 60 en gaz sous pression. Ce gaz peut donc circuler dans les compartiments en direction de l'électrode 10. Il a pour rôle d'améliorer l'isolation entre le four et l'air extérieur, et de refroidir l'élément creux 20.The cylindrical wall 56 is pierced with an orifice 58 connected to a pipe 60 for supplying gas under pressure. This gas can therefore circulate in the compartments in the direction of the electrode 10. Its role is to improve the insulation between the oven and the outside air, and to cool the hollow element 20.

Plus simplement, le gaz peut être insufflé directement dans chacun ou au moins plusieurs des compartiments 42 par des gicleurs traversant le manchon 30.More simply, the gas can be blown directly into each or at least several of the compartments 42 by nozzles passing through the sleeve 30.

De préférence le gaz sous pression est un gaz neutre.Preferably the pressurized gas is a neutral gas.

Par ailleurs en se reportant à la figure 4, on constate que les cloisons 36 de l'élément creux 20 sont profilées de manière à constituer des aubes, pour diriger le gaz neutre entrant dans la couronne 50, à travers les compartiments 42, de manière telle que ces flux de gaz soient inclinés sur l'axe X-X selon la flèche F. Bien entendu, les cloisons 36 peuvent aussi être droites comme dans l'exemple précédemment décrit. De la même manière, des cloisons profilées en aubes peuvent aussi être utilisées lorsqu'on n'insuffle pas de gaz dans l'élément creux 20. Elles offrent une surface de contact plus grande que les cloisons droites et créent donc davantage de perte de charge.Furthermore, with reference to FIG. 4, it can be seen that the partitions 36 of the hollow element 20 are profiled so as to constitute blades, for directing the neutral gas entering the ring 50, through the compartments 42, so such that these gas flows are inclined on the axis XX along the arrow F. Of course, the partitions 36 can also be straight as in the example previously described. Similarly, partitions profiled in blades can also be used when gas is not blown into the hollow element 20. They offer a larger contact surface than straight partitions and therefore create more pressure drop .

Sur les figures 6 et 7 on a représenté l'agencement d'un élément creux 20 sur un four, dont l'ouverture à travers laquelle s'étend l'électrode 10 est constituée d'une part par un orifice 62 du voûtain 6 et d'autre part par une plaque annulaire 64.In Figures 6 and 7 there is shown the arrangement of a hollow element 20 on an oven, the opening through which extends the electrode 10 is constituted on the one hand by an orifice 62 of the roof 6 and on the other hand by an annular plate 64.

La plaque annulaire 64 est disposée parallèlement à la surface extérieure 8 du voûtain 6 et écarté de cette dernière.The annular plate 64 is arranged parallel to the outer surface 8 of the roof top 6 and separated from the latter.

La plaque annulaire 64 présente un diamètre intérieur sensiblement égal au diamètre de l'orifice 62, et sa périphérie est fixée sur le four à l'aide d'un manchon 66 d'axe X-X.The annular plate 64 has an internal diameter substantially equal to the diameter of the orifice 62, and its periphery is fixed to the oven using a sleeve 66 of axis X-X.

La plaque annulaire 64, le manchon 66, et la paroi du four délimitent une zone dans laquelle peut être insufflé un gaz sous pression.The annular plate 64, the sleeve 66, and the wall of the furnace delimit an area into which gas can be blown under pressure.

Dans un premier agencement (voir figure 6) l'élément creux 20 est posé sur la face extérieure 8 du voûtain 6.In a first arrangement (see FIG. 6) the hollow element 20 is placed on the external face 8 of the roof 6.

Dans un second agencement (Figure 7), l'élément creux 20 est posé sur la surface extérieure 70 de la plaque annulaire 64.In a second arrangement (FIG. 7), the hollow element 20 is placed on the outer surface 70 of the annular plate 64.

L'élément creux 20 selon l'invention permet de réduire de manière importante la communication entre l'intérieur et l'extérieur du four, entre lesquels est ainsi assurée une étanchéité relative.The hollow element 20 according to the invention makes it possible to significantly reduce the communication between the interior and the exterior of the oven, between which a relative seal is thus ensured.

En effet, la possibilité de communication est diminuée du fait que l'espace annulaire 22 est réduit par rapport au passage 14, ce qui est possible par le fait que l'élément creux est posé sur une paroi plate sur laquelle il peut glisser.In fact, the possibility of communication is reduced because the annular space 22 is reduced relative to the passage 14, which is possible because the hollow element is placed on a flat wall on which it can slide.

C'est ainsi que dans un four électrique à arc de 150 tonnes, du type basculant, comportant une électrode de 610 mm de diamètre, on a réduit les échanges gazeux à l'aide d'un élément creux, agencé selon les figures 1 et 2, dont le diamètre de la périphérie intérieurement radiale (32, 34) est de 622 mm.Thus, in a 150-ton electric arc furnace, of the tilting type, comprising an electrode of 610 mm in diameter, the gas exchanges were reduced using a hollow element, arranged according to FIGS. 1 and 2, the diameter of the internally radial periphery (32, 34) is 622 mm.

L'utilisation d'un gaz neutre dans le dispositif décrit en regard des figures 4 et 5 ou dans la zone comprise entre la plaque 64 et le voûtain 6 des agencements représentés sur les figures 6 et 7 permet de diminuer les échanges gazeux en réglant le débit du gaz insufflé en fonction de la pression régnant à l'intérieur du four. Ainsi, lorsque le four est en surpression excessive par rapport à l'extérieur, on peut augmenter le débit de gaz insufflé pour empêcher les sorties des fumées vers l'extérieur. A cet effet, les commandes assurant la régulation du débit de gaz insufflé dans l'élément creux 20 peuvent être pilotées par des capteurs détectant la différence de pression entre l'intérieur du four et le milieu extérieur au voisinage des trous d'électrodes.The use of a neutral gas in the device described with reference to Figures 4 and 5 or in the area between the plate 64 and the roof top 6 of the arrangements shown in FIGS. 6 and 7 makes it possible to reduce the gas exchanges by adjusting the flow rate of the blown gas as a function of the pressure prevailing inside the oven. Thus, when the oven is in excessive overpressure with respect to the outside, the flow of blown gas can be increased to prevent the fumes from escaping to the outside. To this end, the controls ensuring the regulation of the flow rate of gas blown into the hollow element 20 can be controlled by sensors detecting the pressure difference between the interior of the furnace and the external environment in the vicinity of the electrode holes.

Claims (16)

1. Dispositif de réduction d'échange gazeux entre l'intérieur (16) et l'extérieur (18) d'un four électrique à arc comportant une voûte (2) possédant au moins une ouverture (4), une électrode (10) traversant axialement l'ouverture (4), un passage (14) délimité entre la paroi de l'ouverture (4) et l'électrode (10), caractérisé en ce qu'il comporte un élément creux (20) posé sur une surface extérieure (8, 70) plane horizontale du four perpendiculaire à l'axe (X-X) de l'électrode (10) et constituant l'extrémité extérieure de l'ouverture, l'élément creux entourant l'électrode avec un jeu annulaire (22) déterminé et pouvant se déplacer librement sur ladite surface extérieure (8, 70). 1. Device for reducing gas exchange between the interior (16) and the exterior (18) of an electric arc furnace comprising a vault (2) having at least one opening (4), an electrode (10) passing axially through the opening (4), a passage (14) delimited between the wall of the opening (4) and the electrode (10), characterized in that it comprises a hollow element (20) placed on a surface external (8, 70) horizontal plane of the furnace perpendicular to the axis (XX) of the electrode (10) and constituting the external end of the opening, the hollow element surrounding the electrode with an annular clearance (22 ) determined and able to move freely on said outer surface (8, 70). 2. Dispositif selon la revendication 1, caractérisé en ce qu'il comporte des butées (24) limitant le déplacement de l'élément creux (20) sur ladite surface extérieure (8 ; 70) lors du basculement du four. 2. Device according to claim 1, characterized in that it comprises stops (24) limiting the movement of the hollow element (20) on said outer surface (8; 70) during the tilting of the oven. 3. Dispositif selon la revendication 1 ou 2, caractérisé en ce que l'élément creux (20) comporte une face intérieure ouverte radialement en vis-à-vis de l'électrode (10). 3. Device according to claim 1 or 2, characterized in that the hollow element (20) has an inner face open radially opposite the electrode (10). 4. Dispositif selon la revendication 3, caractérisé en ce que l'élément creux (20) comporte des compartiments (42) séparés par des cloisons (36) sensiblement radiales, les compartiments étant ouverts en vis-à-vis de l'électrode (10). 4. Device according to claim 3, characterized in that the hollow element (20) comprises compartments (42) separated by partitions (36) substantially radial, the compartments being open opposite the electrode ( 10). 5. Dispositif selon la revendication 4, caractérisé en ce que les cloisons (36) sont angulairement réparties à la périphérie de l'élément creux (20). 5. Device according to claim 4, characterized in that the partitions (36) are angularly distributed at the periphery of the hollow element (20). 6. Dispositif selon les revendications 4 ou 5, caractérisé en ce que les cloisons comportent une extrémité intérieure radiale (40) écartée de la face ouverte de l'élément creux (20) en direction de la périphérie extérieure de l'élément creux (20). 6. Device according to claims 4 or 5, characterized in that the partitions have a radial inner end (40) spaced from the open face of the hollow element (20) towards the outer periphery of the hollow element (20 ). 7. Dispositif selon l'une quelconque des revendications 4 à 6, caractérisé en ce que les cloisons possèdent un profil en forme d'aube (36). 7. Device according to any one of claims 4 to 6, characterized in that the partitions have a blade-shaped profile (36). 8. Dispositif selon l'une quelconque des revendications 1 à 7, caractérisé en ce qu'il comporte des moyens d'insufflation d'un gaz dans au moins plusieurs des compartiments (42). 8. Device according to any one of claims 1 to 7, characterized in that it comprises means for blowing a gas into at least several of the compartments (42). 9. Dispositif selon la revendication 7, caractérisé en ce que la périphérie radialement extérieure de l'élément creux (20) est ouverte et communique avec une couronne creuse (50) alimentée en gaz sous pression. 9. Device according to claim 7, characterized in that the radially outer periphery of the hollow element (20) is open and communicates with a hollow ring (50) supplied with gas under pressure. 10. Dispositif selon la revendication 9, caractérisé en ce que la couronne (50) et l'élément creux (20) comportent des faces latérales venues de matière. 10. Device according to claim 9, characterized in that the crown (50) and the hollow element (20) have lateral faces made of material. 11. Dispositif selon l'une quelconque des revendications 1 à 7, caractérisé en ce que l'ouverture (4) du four est délimitée par un orifice agencé dans un voûtain (6) ayant une surface extérieure horizontale sensiblement plane, un manchon (66) étant fixé coaxialement à l'orifice à l'extérieur du voûtain et comportant à son extrémité opposée à ce dernier une plaque annulaire (64) de diamètre intérieur sensiblement égal au diamètre de l'orifice (62), constituant l'extrémité supérieure de l'ouverture, formant avec le voûtain et le manchon une zone dans laquelle peut être insufflé un gaz sous pression. 11. Device according to any one of claims 1 to 7, characterized in that the opening (4) of the furnace is delimited by an orifice arranged in a roof (6) having a substantially planar horizontal exterior surface, a sleeve (66 ) being fixed coaxially to the orifice outside the roof and having at its end opposite to the latter an annular plate (64) of internal diameter substantially equal to the diameter of the orifice (62), constituting the upper end of the opening, forming with the roof and the sleeve an area into which a gas under pressure can be blown. 12. Dispositif selon la revendication 10, caractérisé en ce que l'élément creux (20) est posé sur la face extérieure (70) de la plaque annulaire (64). 12. Device according to claim 10, characterized in that the hollow element (20) is placed on the outer face (70) of the annular plate (64). 13. Dispositif selon la revendication 10, caractérisé en ce que l'élément creux (20) est en appui glissant sur la face extérieure (8) du voûtain (6). 13. Device according to claim 10, characterized in that the hollow element (20) is in sliding support on the outer face (8) of the roof (6). 14. Dispositif selon la revendication 8, caractérisé en ce que le gaz insufflé est un gaz neutre. 14. Device according to claim 8, characterized in that the blown gas is a neutral gas. 15. Dispositif selon l'une quelconque des revendications 1 à 14 caractérisé en ce que l'élément creux (20) est en acier inoxydable amagnétique. 15. Device according to any one of claims 1 to 14 characterized in that the hollow element (20) is made of non-magnetic stainless steel. 16.- Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que l'élément creux (20) comporte un manchon (21) faisant saillie vers l'intérieur (16) du four et délimitant autour de l'électrode un espace annulaire. 16.- Device according to any one of the preceding claims, characterized in that the hollow element (20) comprises a sleeve (21) projecting inwards (16) from the furnace and delimiting around the electrode a space annular.
EP92401323A 1991-05-22 1992-05-14 Partial sealing device between the inside and the outside of an arc furnace Withdrawn EP0515249A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9106170 1991-05-22
FR9106170A FR2676799A1 (en) 1991-05-22 1991-05-22 PARTIAL SEALING DEVICE BETWEEN THE INTERIOR AND EXTERIOR OF AN ARC FURNACE.

Publications (1)

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EP0515249A1 true EP0515249A1 (en) 1992-11-25

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EP92401323A Withdrawn EP0515249A1 (en) 1991-05-22 1992-05-14 Partial sealing device between the inside and the outside of an arc furnace

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EP (1) EP0515249A1 (en)
JP (1) JPH0688680A (en)
KR (1) KR920021960A (en)
FR (1) FR2676799A1 (en)

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IT202100030824A1 (en) * 2021-12-07 2023-06-07 Danieli Off Mecc ELECTRIC ARC FURNACE FOR THE MELTING OF METALLIC MATERIAL AND STEEL PLANT INCLUDING SAID ELECTRIC ARC FURNACE

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DE3634977A1 (en) * 1985-10-14 1987-04-16 Fuji Kiko Kk ARRANGEMENT FOR TILTING A STEERING WHEEL USING AN AUXILIARY DRIVE
DE19529924C1 (en) * 1995-08-01 1996-10-31 Mannesmann Ag Arc furnace with simple arc spot displacement mechanism
FI123373B (en) * 2008-06-06 2013-03-15 Outotec Oyj sealing device
KR101917594B1 (en) * 2012-10-24 2018-11-13 재단법인 포항산업과학연구원 Apparatus for blocking gap of node hole
CN115127353B (en) * 2022-06-15 2024-09-13 中冶赛迪工程技术股份有限公司 Long-life horizontal air-cooled direct current arc furnace bottom structure

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GB130678A (en) * 1918-03-12 1919-08-14 Theodore Henry Eickhoff Improvements in the Breech Mechanism of Firearms.
GB1332928A (en) * 1970-11-20 1973-10-10 Belousov A A Controlled-atmosphere furnace with gas seal
EP0080335A1 (en) * 1981-11-20 1983-06-01 Coated Electrodes Limited Apparatus for sealing electrodes in electric arc furnaces
EP0437037A2 (en) * 1989-12-11 1991-07-17 Foseco International Limited Method and apparatus for closing the gap between an electrode and its furnace cover in an electric furnace

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GB130687A (en) * 1918-03-14 1919-08-14 Colin Clarence Gow Improvements relating to the Mounting of Electrodes of Electric Furnaces.

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Publication number Priority date Publication date Assignee Title
GB130678A (en) * 1918-03-12 1919-08-14 Theodore Henry Eickhoff Improvements in the Breech Mechanism of Firearms.
GB1332928A (en) * 1970-11-20 1973-10-10 Belousov A A Controlled-atmosphere furnace with gas seal
EP0080335A1 (en) * 1981-11-20 1983-06-01 Coated Electrodes Limited Apparatus for sealing electrodes in electric arc furnaces
EP0437037A2 (en) * 1989-12-11 1991-07-17 Foseco International Limited Method and apparatus for closing the gap between an electrode and its furnace cover in an electric furnace

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT202100030824A1 (en) * 2021-12-07 2023-06-07 Danieli Off Mecc ELECTRIC ARC FURNACE FOR THE MELTING OF METALLIC MATERIAL AND STEEL PLANT INCLUDING SAID ELECTRIC ARC FURNACE
WO2023105541A1 (en) * 2021-12-07 2023-06-15 Danieli & C. Officine Meccaniche S.P.A. Electric arc furnace for melting metal material and steel plant comprising said electric arc furnace

Also Published As

Publication number Publication date
FR2676799A1 (en) 1992-11-27
JPH0688680A (en) 1994-03-29
KR920021960A (en) 1992-12-19

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