Intervention tool for the operation of an electrolytic cell

This intervention tool is movable and designed to reposition an anode assembly of an electrolytic cell. The intervention tool comprises a mount provided with one or more bearing surfaces allowing the intervention tool to bear and be stably supported directly on at least one element of the electrolytic cell, and an intervention unit designed to reposition the anode assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage application under 35 U.S.C. § 371 of International Application PCT/CA2020/050324 (published as WO2020/181379 A1), filed Mar. 11, 2020, which claims priority to French Patent Application No. FR 19/02639, filed Mar. 14, 2019, and the present application claims priority to and the benefit of both of these prior applications, each of which is incorporated by reference in its entirety.

The present invention relates to an intervention tool designed to perform a predetermined intervention on an electrolytic cell, and to an intervention device comprising the intervention tool. The invention also relates to an electrolytic cell comprising the intervention device as well as an aluminum smelter comprising this electrolytic cell. The invention also relates to an intervention method on this electrolytic cell.

Producing aluminum industrially from alumina by electrolysis according to the Hall-Héroult process is well known. To this end, a rectangular electrolytic cell is provided, like that shown inFIG.1, conventionally comprising a steel pot shell31inside which a refractory material coating is laid, a cathode33of carbonaceous material, traversed by cathode electrical conductors designed to collect the electrolysis current at cathode33to conduct it to cathode outlets passing through the bottom or the sides of the pot shell, and an electrolytic bath35in which the alumina is dissolved.

The electrolytic cell comprises several anode assemblies38, each comprising a substantially vertical anode rod36and an anode37formed from at least one anode block suspended from the anode rod36and immersed in this electrolytic bath35. The anodes37are more particularly of the prebaked anode type with prebaked carbon blocks, i.e. baked before introduction into the electrolytic cell.

The electrolytic cell comprises a superstructure30extending above the pot shell31to support and guide a vertically mobile anode frame34. This superstructure30consists, in particular, of at least one beam extending above the pot shell31in a longitudinal direction of the cell and supported by feet arranged at the transverse edges of the pot shell31. Typically, this superstructure30further comprises means for extracting cell gases and devices for supplying alumina. The anode assemblies38are suspended at regular intervals along two rows from the anode frame34by means of removable connectors32pressing the anode rods36against the anode frame34. Electrical conductors39for rising the electrolysis current carrying the electrolysis current from the cathode outlets of the preceding electrolytic cell to the anode frame34extend diagonally upwards from a longitudinal edge of the pot shell31.

The anode blocks being consumed as the electrolysis reaction progresses, the anode assemblies38are progressively lowered towards the cathode33in order to ensure that the distance between the lower surface of the anodes37and the surface of the metal pool forming on cathode33remains substantially constant.

The displacement of the anode assemblies38is collective, since all the anode assemblies38attached to the same anode frame34are displaced simultaneously due to the displacement of this anode frame34.

In order to operate the electrolytic cell, it is typically necessary for the anode assemblies38to be positioned so that the lower surface of their anodes37is in a reference plane, in particular, coinciding with the plane containing the lower surface of the other anodes37of the electrolytic cell, also called anodic plane.

However, as is sometimes the case, some anodes37wear out more or less quickly than adjacent anodes37, slip slightly or are improperly positioned when they are placed in the cell so that their lower face is no longer contained in the anode reference plane, thereby resulting in a problem of electrolytic cell performance or generating detrimental operational problems, for example, a short circuit. The corresponding anode assemblies38must advantageously be repositioned so that the lower surface of the anodes37is once again located in the anode reference plane. This individualized repositioning of an anode assembly38is also called anode height adjustment. The anode frame34, which collectively supports and displaces a plurality of anode assemblies38, does not allow such an adjustment to be made.

To overcome this difficulty, a known solution is to equip each anode assembly38with an actuator or jack allowing it to be moved individually. However, this individual motorization solution is relatively expensive and it is not easy to implement in pre-existing aluminum smelters.

Another known solution is the use of a handling crane circulating in the pot room above the electrolytic cells, also called a pot tending machine, guided by an operator, to reposition an improperly positioned anode assembly. To this end, the electrolysis service machine, circulating in the potroom above the electrolytic cells, includes a screw-driving machine to tighten-loosen the removable connector, working in conjunction with a gripping arm allowing to grip the anode rod, typically by its upper end, and reposition the anode assembly by raising or lowering it. However, the number of electrolysis service machines in an aluminum smelter is limited and these machines are required for multiple operations, so their availability is limited. In addition, electrolysis service machines cannot cross paths in the potroom. Consequently, an electrolysis service machine cannot be used as part of a process for continuous improvement of operations involving regular repositioning of the anode assemblies.

Generally speaking, document FR3024466 discloses a vehicle for the operation of electrolytic cells, which can move from one electrolytic cell to another in order to carry out an intervention therein. However, this vehicle circulates in the aisles used for the movement of other vehicles performing various operations on the cells, or in which pallets are temporarily stored for operations on the cell, in particular to support new or used anode assemblies.

Consequently, the present invention aims to overcome all or part of these disadvantages by proposing an intervention tool designed to intervene on an electrolytic cell, in particular, for quickly repositioning an anode assembly, at low cost, without hampering the circulation of operators or other vehicles.

To this end, the subject matter of the present invention is a movable intervention tool designed for repositioning an anode assembly of an electrolytic cell, characterized in that the intervention tool comprises a mount provided with one or more bearing surfaces allowing the intervention tool to bear and be stably supported directly on at least one element of the electrolytic cell, and an intervention unit designed to reposition the anode assembly.

The intervention tool according to the invention is adapted to be positioned on the electrolytic cell, execute an occasional intervention therein and subsequently be moved, for example, by the electrolysis service machine, a vehicle moving in the aisles or a handling device like the one which will be described below.

The intervention tool saves time since the electrolysis service machine is possibly only required for positioning the tool before the intervention and for its subsequent retrieval after the intervention. Indeed, the intervention is carried out autonomously by the intervention tool instead of the electrolysis service machine.

Furthermore, the intervention tool allows the electrolytic cell to be the element which supports the weight of the intervention tool during the intervention. Therefore, when repositioning an anode assembly, this allows the weight of the anode assembly, gripped by the intervention tool, to be supported by the electrolytic cell.

Repositioning means adjusting the height of the anode of the anode assembly so that its lower surface is in a determined position.

According to one embodiment, the bearing surface(s) are configured to allow the intervention tool to be supported by a fixed element with respect to an anode frame of the electrolytic cell.

This element may be the anode frame itself, a connector, a connector axis, or a hook supporting the connector. This feature allows the intervention tool to remain in a reference frame of fixed displacement with respect to the anode frame and, therefore, to avoid problems linked to the continuous displacement of the anode frame and the other cell elements which are linked thereto. Therefore, the repositioning of the anode assembly can be carried out according to a determined position differential which will not be impacted by the duration of the intervention combined with the continuous displacement of the anode frame.

Advantageously, the bearing surface(s) define a notch designed to engage an axis of an electrolytic cell connector.

According to one embodiment, the mount of the intervention tool comprises reversible fixing means adapted to create a reversible attachment between the mount and the electrolytic cell element.

Thus, when the intervention tool is in a working position, bearing on at least one element of the cell, the intervention tool can also be attached to at least one element of the cell to further improve the stability of the intervention tool on the cell and increase the stress levels that the intervention tool may undergo during the intervention on the cell. This element may be the anode frame itself, a connector, a connector axis, or a hook supporting the connector.

Advantageously, the reversible fixing means comprise one or more locking tabs, possibly movable with respect to the mount between a retracted position and a deployed position, configured to cooperate with an element of the electrolytic cell when the intervention tool is in working position, more precisely with a fixed element with respect to the anode frame, such as a connector, a connector axis, an anode frame, or a hook supporting the connector. Therefore, the locking tab(s) along with the bearing surface(s) make it possible to attach the intervention tool to the electrolytic cell.

According to one embodiment, the intervention unit is configured to allow vertical displacement of the anode assembly with respect to the frame.

According to one embodiment, the intervention unit comprises a part movable with respect to the frame, displacement means for moving the movable part in translation with respect to the frame, the movable part comprising engagement means configured to engage an anode rod of the electrolytic cell anode assembly in order to secure the anode rod and the movable part in translation.

These features allow the intervention tool to reposition an anodic assembly for which a possible optimization of vertical positioning was detected, i.e. an individualized displacement of an anodic assembly, in particular, in order to reposition its lower surface in the anode plane. The movable part may be moved with the anode assembly in vertical translation, up or down with respect to the mount, based on the desired positioning of the anode assembly.

Such a movable intervention tool, in particular along the superstructure, by means of a handling device facing each of the cell anode assemblies, makes it possible, if necessary, to individually reposition all the anode assemblies of the cell, one by one. The engagement means, for securing the anode rod and the movable part of the intervention tool in translation, include conventional gripping means such as clamps or a vise gripping the anode rod between two opposite jaw members.

According to one embodiment, the intervention unit comprises tightening/loosening means adapted to tighten/loosen a connector holding the anode assembly in position in the electrolytic cell.

These tightening/loosening means are advantageously a screwdriver engaging a threaded rod of the connector when the intervention tool is positioned in a working position.

According to one embodiment, the intervention tool, more particularly the mount, comprises catching means complementary to the catching means of a handling device.

Thus, the movable intervention tool can be brought into the working position by a handling device.

The catching means may be configured to hang a suspension cable allowing the tool to be lowered onto the electrolytic cell in order to perform the predetermined intervention or to lift the tool in order to move it away from the electrolytic cell.

According to one embodiment, the intervention tool comprises position detection means. The position detection means may be of the contact sensor or optical sensor type. Thus, the intervention tool can detect its bearing on the electrolytic cell elements and consequently actuate the intervention unit.

Advantageously, the intervention tool comprises wired supply means and an automatic reel designed for winding the wired supply means. An automatic reel is a reel exerting a restoring force into the winding position on the wire, pipe or cable, and allowing the unwinding of the wire, pipe or cable by a pulling force greater than the restoring force on the wire, pipe or cable.

According to a second aspect, the invention also relates to an intervention device comprising an intervention tool having the aforementioned features and a handling device, the handling device comprising a chassis carrying the intervention tool and displacement means adapted to allow displacement of the chassis, the displacement means being adapted to bear on the superstructure.

Thus, the intervention tool can be brought by the handling device to various locations along the superstructure of the electrolytic cell in order to execute an operation therein, without the need for the electrolysis service machine to intervene, and without the need to circulate in the aisles adjacent to the electrolytic cells.

Superstructure refers to the structure supporting the anode frame and any fixed element of the electrolytic cell attached thereto, such as, for example, means for extracting cell gases and devices for supplying alumina. This superstructure comprises, for example, a beam extending above the pot shell in a longitudinal direction of the cell and supported by feet disposed at the transverse edges of the pot shell. The superstructure, on which the displacement means are bearing, supports these displacement means and the handling device.

Therefore, the intervention device makes it possible, in particular, to make the same intervention tool available to several anode assemblies arranged at regular intervals along the superstructure of the electrolytic cell, thereby reducing costs.

Therefore, the intervention device offers the possibility of regular individual repositioning of the anode assemblies and also increases the availability of electrolysis service machines for other operations, also reducing operating costs.

According to one embodiment, the handling device comprises lifting means configured to raise or lower the intervention tool between a parking position, making it possible to keep the intervention tool at a distance from the electrolytic cell, and a working position, making it possible to lower the intervention tool in contact with the electrolytic cell.

These lifting means may consist of jacks or articulated arms, but, advantageously, according to one embodiment of the invention, the lifting means are cable lifting means.

Cable lifting means refers to any lifting means comprising a long and flexible element designed to lower or tow a load from above such as a cable, tether, strap, rope, chain, or equivalent.

The use of cable lifting means, in essence simple, reliable and inexpensive, is made advantageous due to the positioning of the chassis above the superstructure, that is to say, above an intervention area of the intervention tool.

According to one embodiment, the lifting means comprise a motorized hoist or winch.

According to one embodiment, the lifting means comprise means for detecting the arrival of the intervention tool in the working position.

The height at which the intervention tool is in the working position depends on the height of the anode frame which varies over time. Therefore, halting the lowering of the intervention tool can be controlled when the intervention tool comes into contact and bears on the anode frame or a cell element, fixed with respect to the anode frame, such as the connector, the connector axis, or the hook formed on the anode frame to support the connector. The detection means may be of the contact sensor or optical sensor type.

According to one embodiment, the handling device comprises guide means configured to guide the intervention tool according to a predetermined path from the parking position to the working position.

This feature allows to bring the intervention tool to an intervention zone precisely.

According to one embodiment, the guide means comprise two parallel flanges between which the intervention tool extends in the parking position, each flange comprising a groove designed to receive and guide an element attached to the intervention tool.

These flanges ensure robust and efficient guidance, preventing any tilting or unsuitable backlash.

According to one embodiment, the handling device comprises a retaining member designed to prevent the chassis carrying the intervention tool from tilting on either side of the superstructure.

This allows lowering or raising the intervention tool in a secure manner.

According to one embodiment, the handling device carries two intervention tools arranged on opposite sides of the chassis.

This makes it possible to balance the masses at the handling device, and to have two intervention tools available per electrolytic cell, each intervention tool being designed to intervene on one half of the electrolytic cell. Therefore, the operating efficiency of the electrolytic cell and the aluminum smelter is improved.

Alternatively, the handling device carries a single intervention tool arranged on a rotary platform positioned on the chassis.

According to one embodiment, the displacement means allow the displacement of the chassis along the superstructure of the electrolytic cell.

According to one embodiment, the chassis moves above the superstructure.

Thus, the same tool can advantageously easily intervene on both sides of the electrolytic cell.

According to a third aspect, the invention relates to an electrolytic cell comprising a superstructure, an anode frame supported by the superstructure, and an intervention device having the aforementioned features, wherein the superstructure comprises a surface on which the means of displacement are bearing.

Thus, the handling device, designed to transport an intervention tool, moves on the electrolytic cell instead of moving in the aisles serving the electrolytic cells. This reduces congestion in the potroom and improves safety.

All the electrolytic cells of an aluminum smelter may be equipped with an intervention device allowing the intervention tool to move and carry out interventions in different areas of each electrolytic cell without generating a detrimental congestion in the work aisles adjacent to the electrolytic cells, or mobilizing an electrolysis service machine.

According to one embodiment, the surface on which the displacement means are bearing is an upper surface of the superstructure.

This embodiment is the simplest since the superstructure typically comprises a substantially planar upper surface extending over the entire length of the electrolytic cell.

According to one embodiment, the superstructure and/or the displacement means form a path of displacement for the chassis over at least the entire length of the anode frame.

Thus, the intervention tool, carried by the handling device, can be moved and brought into position for intervention near all the anode assemblies supported by the anode frame.

According to one embodiment, the displacement path presents a parking track at one end of the electrolytic cell.

This allows the handling device to clear the space above the anode frame, for example, for the passage or intervention of an electrolysis service machine.

According to one embodiment, the displacement means comprise guide means designed to guide the chassis in translation in a longitudinal direction of the electrolytic cell.

These guide means ensure precise positioning of the handling device on the superstructure and may, in particular, be rails forming the displacement path and cooperating with wheels arranged on the chassis.

According to one embodiment, the displacement means comprise drive means configured to move the chassis along the superstructure.

The handling device can move autonomously on the superstructure of the electrolytic cell.

According to a fourth aspect, the invention relates to an aluminum smelter comprising at least one electrolytic cell having the aforementioned features.

According to a fifth aspect, the subject matter of the invention is an intervention method on an electrolytic cell by means of an intervention tool having the aforementioned features, including the following steps:bringing the intervention tool into a working position,carrying out the intervention using the intervention tool,retrieving the intervention tool.

According to a particular embodiment, the intervention on the electrolytic cell is a repositioning of an anode assembly and includes the following steps:engaging the intervention tool against an anode rod of the anode assembly to be repositioned,loosening an electrolytic cell connector to release the anode rod,displacing the anode assembly so that a lower surface of the anode assembly is brought to a predetermined position,tightening the connector,disengaging the intervention tool and the anode rod.

FIG.2shows an intervention tool2according to an embodiment of the invention. The intervention tool2is designed to carry out a predetermined operation on an electrolytic cell3, for example, an anodic assembly repositioning, as will be described in more detail below. The intervention tool2can be moved to an intervention zone by means of an electrolysis service machine or, preferably, by means of a handling device1with which it jointly forms an intervention device.

With reference toFIG.7, the intervention tool2comprises a mount22, provided with one or more bearing surface(s)220allowing the intervention tool2to bear and be supported in a stable manner directly on at least one element of the electrolytic cell3, more precisely on a fixed element with respect to the anode frame34, such as connector32, connector32axis320, anode frame34or hook322supporting the connector32. For example, the mount22comprises a bearing surface220adesigned to bear against an upper face of the anode frame34, and/or a bearing surface220bdesigned to bear against a lateral face of the anode frame34, and/or a bearing surface220c, corresponding here to the bottom of a notch222, designed to bear against the axis320of the connector32. The bearing surface(s)220are configured to allow the intervention tool2to stably bear by gravity on the electrolytic cell3and be fully supported, if necessary, by the electrolytic cell3. As shown inFIG.7, the bearing surfaces220may comprise two orthogonal bearing surfaces220a,220b, in particular, a horizontal bearing surface220aand/or a vertical bearing surface220b. The bearing surfaces220may include a notch222, the bottom of which forms one of the bearing surfaces220.

The mount22may also include reversible fixing means designed for creating a reversible attachment between the mount22and at least one element of the electrolytic cell3. The reversible fixing means may comprise one or more locking tabs, possibly movable with respect to the mount22between a retracted position and a deployed position, configured to cooperate with an element of the electrolytic cell3when the intervention tool2is in the working position, more precisely, with a fixed element with respect to the anode frame34, such as connector32, axis320of connector32, anode frame34, or hook322supporting the connector32. Therefore, the locking tab(s), together with the bearing surface(s)220, make it possible to attach the intervention tool2to the electrolytic cell3.

The intervention tool2is designed to carry out a predetermined operation on the electrolytic cell3, such as, for example, the repositioning of an anode. To this end, the intervention tool2comprises an intervention unit designed to reposition an anode assembly38. In this case, the intervention unit may comprise engagement means allowing to grip an anode rod36of an anode assembly38of the electrolytic cell3, and means for driving these engagement means in translation in order to vertically move the anode assembly38. More specifically, the intervention unit comprises a part24movable in translation with respect to the mount22, this movable part24supporting the engagement means, and drive means for driving the movable part24in translation along the vertical axis Z with respect to the mount22. The movable part24and the mount22may be connected by a guide slide26. These features make it possible to move the anode assembly38, by raising or lowering it, over a relatively short distance, typically about 100 mm, but sufficient to return the lower surface of the anode block of this anode assembly38to the desired location, for example, in the anode plane.

With reference toFIG.10, the engagement means may be gripping means making it possible to grip the anode rod36and comprising a vertical screw200with reverse pitch double threading, two cams202, each engaged with one of the threads of the vertical screw200so that a rotation of the screw200brings the cams202closer or further apart, a pair of upper jaws204and a pair of lower jaws206. Each upper jaw204is rotatably connected to one of the lower jaws206. Each cam202is engaged in a lumen208of the upper or lower jaws204,206. Thus, bringing the cams202closer or further apart due to the rotation, in one direction or the other, of the threaded rod200, causes a tightening or a widening of the upper and lower jaws204,206in order to secure the movable part24of the intervention tool2with the anode rod36.

With reference toFIGS.8and9, the means for driving the movable part24with respect to the mount22may comprise one or more jacks240, of the screw type, preferably trapezoidal, which can be actuated by an electric motor242. InFIG.8, the jack240is in the retracted position, while inFIG.9, the jack240is in the deployed position. The position of the jack240, before the step of engaging the anode rod36by the gripping means, may depend on the direction of the displacement necessary for repositioning the anode assembly38, namely lifting or lowering of the anode assembly38.

The intervention unit advantageously comprises means for tightening/loosening a connector32of the electrolytic cell3. The connector32may be the type which comprises rotary levers actuated by a threaded rod324, as disclosed in patent document WO2013159218. The means for tightening/loosening the intervention tool2may comprise a screwdriver28designed to engage and pivot the threaded rod324of the connector32in one direction or the other in order to loosen or tighten the grip exerted by the connector32and the anode frame34on the anode rod36. The tightening/loosening means are provided on the mount22to engage the tightening/loosening means of the intervention tool2with the corresponding components of the connector32when positioning the intervention tool2in a working position, and to maintain this engagement during the intervention, and, in particular, when the movable part24of the intervention tool2is displaced with respect to the mount22.

Furthermore, the intervention tool2may comprise wired supply means, of the electric cable or pneumatic hose type, designed, in particular, to supply the drive, engagement and/or tightening/loosening means of the intervention tool2, and an automatic reel designed for winding the wired supply means. Alternatively, or in addition, the intervention tool2may carry one or more energy storage units, such as batteries.

With reference toFIG.2, the invention also relates to an intervention device comprising one or more intervention tools2having the aforementioned features, as well as a handling device1designed for transporting this or these intervention tool(s)2.FIG.3shows that the handling device1is advantageously designed to transport two intervention tools2. Where appropriate, each intervention tool2is designed to intervene on one half of the electrolytic cell3.

With reference toFIGS.2and3, the handling device1comprises a chassis10, and displacement means for moving the chassis10along a superstructure30of the electrolytic cell3.

The chassis10extends longitudinally along a transverse axis X, designed to extend parallel to a transverse direction of the electrolytic cell3. The chassis10may take the form of a support plate or platform (FIG.2), or even a beam (FIGS.12to14).

When the handling device1carries two intervention tools2, these two intervention tools2are advantageously positioned on opposite sides of the chassis10along the transverse axis X.

The displacement means support the chassis10. The displacement means are configured to bear on a surface300, advantageously an upper surface of the superstructure30, and to allow a translation of the handling device1in a longitudinal direction of the electrolytic cell3, along a displacement path defined by the upper surface300of the superstructure30.

With reference toFIGS.2,3,5and12to14, the displacement means may comprise wheels or rollers12rotatably mounted on the chassis10around the transverse axis X. The displacement means may also include guide means, such as a rail41attached, for example, to the superstructure30, designed to cooperate with the wheels or rollers12.

The displacement means of the handling device1may comprise drive means, such as a motor which may be loaded on the chassis10to allow the handling device1to move along the superstructure30, in the longitudinal direction Y of the electrolytic cell3. Alternatively, as shown inFIG.4, the displacement means may comprise a motor42arranged on the superstructure30and a transmission member44, such as a chain actuated by the motor42and attached to the chassis10. This motor42may be arranged at one end of the displacement path, for example, in a parking track40.

With reference toFIG.5, the chassis10advantageously comprises one or more retaining members14designed to prevent the handling device1from tilting on one side or the other of the superstructure30. The retaining members14may be an L-shaped tab or hook designed to engage under a surface of the displacement means, for example, under a head of the rail41, or under a surface of the superstructure, to prevent the chassis10of the handling device1from a vertical lifting with respect to the superstructure30.

The handling device1may include lifting means. The lifting means are configured to individually move the intervention tool(s)2between a parking position (FIGS.2and3on the right;FIG.12;FIGS.13and14on the left), where the intervention tool2is at a distance from the electrolytic cell3to allow it to be conveyed along the electrolytic cell3, and a working position (FIGS.2and3on the left;FIG.6;FIGS.13and14on the right), where the intervention tool2is lowered in contact with the electrolytic cell3in order to carry out a predetermined operation, for example, an anode repositioning. In the parking position, the intervention tools2are near or in contact with the chassis10. In the working position, the intervention tools2are at a distance from the chassis10, at a greater distance from it than in the parking position.

With reference toFIGS.2,3,6and12to14, the lifting means advantageously comprise, for each intervention tool2, a winch100with a motor, for example, an electric motor, having a cable102designed to be connected to the intervention tool2. The cable102may comprise a lifting beam104. The lifting means may also comprise one or more return pulleys106which can be arranged above a horizontal plane containing the chassis10. For example, the return pulleys106are rotatably mounted about a longitudinal axis Y on support arms108which extend from and above the chassis10. The winch(es)100are advantageously positioned above the track defined by the displacement means, in the center of the chassis10. Alternatively, the lifting means may consist of jacks or articulated arms.

With reference toFIGS.2,3and6, the handling device1comprises, for each intervention tool2, guide means configured to guide the intervention tool2according to a predetermined path, for example, an inverted L-shaped path, starting from the parking position towards the working position.

The guide means may include grooves16designed to receive and guide a rotary axis or roller20of the intervention tool2. The grooves16may be formed on two parallel flanges18connected to the chassis10and defining between them a space designed to receive the intervention tool2in the parking position. Each groove16preferably comprises a lower portion162, which advantageously extends along a vertical axis Z orthogonal to the longitudinal and transverse axes Y, X, substantially under a horizontal plane containing, or flush with, the displacement means, and an upper portion160, which extends obliquely to the lower portion162, at or above a horizontal plane containing the chassis10or displacement means of the handling device1. The upper portion160preferably extends externally from the lower vertical portion162, that is to say, away from the chassis10and the electrolytic cell3. In the parking position, the rotary axis or roller20of the intervention tool2is located in the upper portion160of the groove, while, in the working position, the rotary axis or roller20of the intervention tool2is located in the lower portion162of the groove. Preferably, each flange18comprises two similar and parallel grooves16. These doubled grooves16prevent the intervention tool2from tilting around the rotary axis or roller20placed in the groove16.

The handling device1may include means for supporting each intervention tool2in the parking position. Thus, the intervention tool2bears, at least in part, on these support means. The support means may be a side wall of the groove(s)16of the flanges18.

The handling device1may comprise wired supply means, of the electric cable or pneumatic hose type, designed to supply the lifting means and/or a motor making it possible to move the handling device1on the superstructure30, and an automatic reel designed for winding the wired supply means. Alternatively, or additionally, the handling device1may carry one or more energy storage units, such as batteries.

Each intervention tool2is connected to the handling device1via the cable102and the guide means described above.

The handling device1, and, more particularly, the lifting means, advantageously comprises detection means, such as, for example, a contact or optical sensor11, shown diagrammatically inFIGS.8and9, making it possible to ensure the positioning of the intervention tool2in a working and/or parking position.

According to one embodiment, the intervention tool2, more particularly the mount22, comprises catching means complementary to the catching means of the handling device1. The catching means may be configured to allow hanging a suspension cable102for lowering the intervention tool2onto the electrolytic cell3in order to carry out the predetermined intervention, or for raising the intervention tool2in order to move it away from the electrolytic cell3. Although not shown, the catching means may include, for example, rings or hooks allowing the passage of a cable102. The catching means may be provided on an upper part of the mount22, for example, opposite the bearing surfaces220which may be provided on a lower part of the mount22.

The invention also relates to an electrolytic cell3comprising a superstructure30, an anode frame34supported by the superstructure30, an anode assembly38, a connector32for removably suspending the anode assembly38from the anode frame34, and a handling device1as described above, the handling device1being able to carry one or more intervention tools2.

With reference toFIGS.3,6,12, the superstructure30has a surface300, in particular an upper surface, on which the displacement means are bearing. The superstructure30and/or the displacement means form a displacement path of the chassis10of the handling device1over at least the entire length of the anode frame34, or a pot shell of the electrolytic cell3. The surface300extends in a horizontal plane XY. The displacement path is advantageously rectilinear, positioned in the center of the electrolytic cell3, symmetrical with respect to the median plane YZ of the electrolytic cell3.

The displacement path may extend beyond a vertical projection of the anode frame34or the pot shell of the electrolytic cell3. In particular, as illustrated inFIG.11, the displacement path may comprise a storage track40to store the handling device1, for example, in the absence of intervention, or to free up space above the electrolytic cell3for the passage or intervention of an electrolysis service machine. The storage track40is located at one end of the displacement path and the electrolytic cell3, for example, in a cantilever manner. Although not shown, the storage track40may extend in a horizontal plane which is below the plane containing the surface300of the superstructure30, in order to free up more space above the electrolytic cell3.

If necessary, the positioning of the handling device1on the storage track40can allow recharging electrical batteries of different equipment, such as the displacement means, lifting means and/or intervention tool2.

It will be noted that the electrolytic cell3or the handling device1may advantageously include means for controlling the position of the handling device1, such as an encoder installed in the motor42designed to drive the handling device1, as well as a sensor for both the zero point, for example, a first end of the displacement path such as the storage track40, and the end of travel, such as a second opposite end of the displacement path.

Alternatively, markings and associated detectors may make it possible to precisely determine the stops of the chassis10facing the anode assemblies38, whose positions always remain the same and are at regular intervals, as shown inFIG.14.

In addition, although not shown, the electrolytic cell3, the handling device1or the intervention tool2may be equipped with wired or wireless communication means, known to the person skilled in the art, for communicating with a control unit provided within the aluminum smelter and designed to control the displacements and operations of the handling device1and the intervention tool2.

The invention also relates to an aluminum smelter comprising a plurality of electrolytic cells3including at least one electrolytic cell3as described above. Preferably, all of the aluminum smelter electrolytic cells3have the above features. The aluminum smelter may include one or more electrolysis service machines designed to transport the intervention tool2or to move above the handling devices1present on the displacement path of the superstructure30.

Furthermore, the aluminum smelter or the electrolytic cell(s)3advantageously comprises means for measuring the current circulating in each of the anode assemblies38, such as, for example, Hall effect sensors, as disclosed in U.S. Pat. No. 6,136,177. The aluminum smelter may include a control unit designed to control the displacements and operations of the handling devices1, and intervention tools2based on the results of the measurements of the current circulating in each of the anode assemblies38, and based on information received about the positioning and operations of the handling devices1and/or the intervention tools2and/or the electrolysis service machines.

The invention finally relates to an intervention method on an electrolytic cell3as previously described. This method includes the steps of:bringing the intervention tool2into a working position, by means of an electrolysis service machine or the handling device1,carrying out the intervention on the electrolytic cell3using the intervention tool2,retrieving the intervention tool2, by means of an electrolysis service machine or the handling device1.

The method may include an initial step of measuring an operating parameter of the electrolytic cell3, such as the intensity of the current circulating in each of the anode assemblies38.

The lowering of the intervention tool2down to the working position may include the bearing of the intervention tool2on an element of the electrolytic cell3, more precisely, a fixed element with respect to the anode frame34, such as the connector32, the axis320of the connector32, the anode frame34, or the hook322supporting the connector32.

The lowering of the intervention tool2down to the working position may be followed by a step of attaching the intervention tool2to the electrolytic cell3in the working position, more precisely, on an element of the electrolytic cell3fixed with respect to the anode frame34, such as the connector32, the axis320of the connector32, the anode frame34, or the hook322supporting the connector32.

Preferably, the step of carrying out the intervention by means of the intervention tool2consists in repositioning an anode assembly, for example, the displacement of an anode assembly38in order to reposition the lower face of the anode block in the anode reference plane. Repositioning an anode assembly38may include the following steps:displacing the intervention tool2from a parking position to a working position,engaging the intervention tool2against an anode rod36of the anode assembly38to be repositioned, for example, gripping of the anode rod36by the intervention tool2,loosening a connector32of the electrolytic cell3to release the anode rod36,displacing the anode assembly38so that a lower face of the anode block of the anode assembly38is brought to a predetermined position,tightening the connector32,disengaging the intervention tool2and the anode rod36,moving the intervention tool2into a parking position.

Advantageously, the loosening step of the connector32is a partial loosening step so that the connector32maintains contact between the anode rod36and the anode frame34. The tightening and loosening of the connector32are advantageously carried out by the tightening/loosening means of the intervention tool2.

The repositioning of the anodic assembly38may also include an initial displacement step of the chassis10on the superstructure30until it faces an anodic assembly38to be repositioned, when the intervention tool2is transported by the handling device1.

The method may also include the communication of information or control signals between the aluminum smelter control unit and the handling devices1and/or the intervention tools2and/or the electrolysis service machines in order to control their respective displacements and operations.

Obviously, the invention is in no way limited to the embodiment described above, this embodiment having been given only by way of example. Modifications are possible, in particular in terms of the composition of the various devices, or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.