WO2016128661A1

WO2016128661A1 - Unit for operating an aluminum production plant, aluminum production plant, and method for operating a plant of said type

Info

Publication number: WO2016128661A1
Application number: PCT/FR2016/050266
Authority: WO
Inventors: Abel VALERIO
Original assignee: Fives Ecl
Priority date: 2015-02-09
Filing date: 2016-02-08
Publication date: 2016-08-18

Abstract

The unit for operating an aluminum production plant comprises a lifting system that includes: - an upper portion (112) secured to a movable carriage of the plant; - an intermediate portion (113) which can move relative to the upper portion along a vertical upper guiding axis (114) and which supports a first tool (101) that can intervene in a first operational region (161) when the intermediate portion is in the bottom position; - a lower portion (115) which can move relative to the intermediate portion along a vertical lower guiding axis (116) and which supports a second tool (120) that can intervene in a second operational region (162) when the lower portion is in the bottom position. The operational regions are located at a distance from one another in the (X, Y) directions, and the first operational region is higher than the second operational region in the (Z) direction.

Description

Unit for operating an aluminum production plant, aluminum production plant and method of operating such an installation

The present invention relates to a unit for operating an igneous electrolysis aluminum production plant comprising a service machine comprising a service module mounted on a carriage, and a crane on which the machine is mounted. The invention also relates to an igneous electrolysis aluminum production plant including such a unit, and a method of operating such an installation.

Aluminum is conventionally produced in a plant called an aluminum smelter, by igneous electrolysis, according to the Hall-Héroult process.

An aluminum smelter traditionally comprises, in a building, several hundred electrolysis cells connected in series and traversed by an electrolysis current. The electrolysis cells extend in a transverse direction and are arranged next to each other in a longitudinal direction. Thus, on the one hand, there is a transverse access path between two adjacent cells, and on the other hand a wider longitudinal operating aisle at the end of all the cells. The driveway allows the movement of vehicles and personnel on foot.

An electrolysis cell conventionally comprises a steel tank having an inner lining of refractory materials, and containing a cathode of carbon material and an electrolytic bath in which is dissolved alumina. The cell also includes several anode assemblies. Each anode assembly comprises at least one anode immersed in this electrolytic bath and an anode rod sealed in the anode and mounted on an anode support. The anodes are generally made from carbonaceous blocks cooked prior to their introduction into the electrolysis cell. In addition, electrical conductors allow the routing of the electrolysis current between the cells of the installation.

The vessel has an opening through which the anode assemblies are introduced. In order to limit the thermal losses and to prevent the diffusion of harmful gases generated during the electrolysis reaction from the electrolysis cell, it is planned to close the opening of the tank with a set of removable covers, generally placed one at a time. next to the others in a longitudinal direction of the electrolysis cell, that is to say along the transverse direction, so as to form a closed chamber.

However, the anode assemblies are consumed during the electrolysis reaction and must therefore be replaced by new anode assemblies. then a change of anode assembly, some of the hoods are removed to open an access window inside the tank.

The spent anode assembly is extracted from the electrolysis cell through this access window, by means of an anodic assembly gripper, and deposited on a support, where it is stored temporarily before it can be taken to to a revaluation zone. Then the crusts formed by the cover products periodically introduced into the electrolytic bath are removed and deposited in a scallop collection device with a cleaning tool also called scallop. This tool is inserted into the electrolysis cell through the access window. A new anode assembly is then introduced into the electrolysis cell, via the access window, in place of the spent anode assembly, by means of the anode assembly gripper. Finally, the removable covers initially removed are replaced to close the access window.

These operations are performed largely by means of a service unit comprising:

a traveling crane which has two transverse beams and which is mounted longitudinally movable in the building above the electrolysis cells;

a carriage mounted on the two girders of the traveling crane movably in the transverse direction, and carrying handling and intervention tools.

For reasons of operator safety and gain in cycle time, it is desirable to perform as many steps as possible by means of the service unit. However, this improvement approach comes up in practice with design problems. Indeed, the addition to the carriage of new tools generally results in an increase in the overall size of the carriage and the service module, which is not always possible without changing the structure of the building of the facility. In addition, the increase in the number of tools generally implies an increase in the means of support and actuation of these tools, therefore the overall cost of the service unit.

In addition to the problems associated with increasing the congestion of the service module, the arrangement of a large number of tools on the same service module must be optimized to allow interventions with each tool, in the same cell , by limiting the movements of the carriage, in particular to obtain a gain in cycle time.

Moreover, during the electrolysis, a crust is formed on the surface of the molten bath located in the electrolytic cell. This crust is thus formed around the anode and, when the anode is worn and must be replaced, it is taken in this crust. So, for to be able to remove the spent anode assembly, it is first necessary to break the crust formed around the spent anode.

For this purpose, it is known to use a tool to break the crust, this tool being moved on at least a portion of the periphery of the spent anode. However, the techniques known to break the crust have a number of disadvantages.

According to a first technique, the tool is mounted at the end of an articulated arm, the arm being animated with movements making it possible to move the tool on at least a part of the periphery of the used anode. This involves the implementation of complex mechanisms for the articulation of the arm required for the movement of the tool, increasing the cost and decreasing the robustness of the service module. In addition, the appropriate positioning of the tool relative to the anode to be disengaged may be difficult, and / or require dedicated positioning means, possibly expensive.

According to a second technique, the tool is fixedly mounted on a rigid structure and / or with limited movements, and it is an operator who controls the displacement of this structure - therefore of the tool - to move the tool on at least a part of the periphery of the spent anode. Although this solution is structurally less complex, it does not give complete satisfaction, because the intervention of an operator induces a longer intervention time and increased risk of error.

The present invention aims to remedy in particular the disadvantages mentioned above.

For this purpose, a service module for the operation of an igneous electrolysis aluminum production facility is proposed, the installation comprising cells which contain anode assemblies and which are closed by covers, the module of service being intended to be mounted on a carriage arranged to be able to move in a transverse direction (Y) with respect to a traveling crane which extends in a transverse direction (Y) and which is designed to move in a longitudinal direction ( X) above the cells, the service module comprising at least one elevation system which comprises an upper portion intended to be fixed to the carriage and handling and intervention tools.

The at least one elevation system further comprises:

an intermediate portion movable relative to the upper portion along a substantially vertical upper guide axis, between a high position and a low position, the intermediate portion carrying a first tool for performing an intervention in a first action zone in the lower position of the intermediate portion; a lower portion movable relative to the intermediate portion along a substantially vertical lower guide axis, between a high position and a low position, the lower portion carrying a second tool intended to perform an intervention in a second action zone in the lower position of the lower portion;

the elevation system being shaped so that the first and second zones of action are distinct and located at a distance from one another:

in projection in a substantially horizontal plane (X, Y) parallel to the longitudinal direction (X) and the transverse direction (Y);

and / or in the vertical direction (Z), the first action zone being higher than the second action zone.

Thus, it is planned to set up two tools on one and the same elevation system, this being made possible by the fact that the zones of action of these tools are offset from one another to avoid interference. between the tools. This offset may exist in a horizontal plane, or along the vertical direction, or both in a horizontal plane and along the vertical direction. Thus, the first tool and the second tool can operate simultaneously without interfering with each other.

In practice, the tools are mounted on the elevation system by being offset relative to one another in projection in a horizontal plane (X, Y), and are used at different altitudes by moving the intermediate portions and or higher. Typically, the first tool can be mounted at the bottom of the intermediate portion and the second tool can be mounted at the bottom of the lower portion.

These features bring in particular advantages in terms of compactness of the service module and cost, insofar as a single elevation system is provided for two tools.

The first action zone is preferably located at the hoods or in a lower position than said hood. The second zone of action is preferably located at the level of the cell, that is to say below the level of the hoods. Thus, the tools of the service module are arranged to allow interventions with each tool in the same cell, without having to move the carriage. This configuration makes it possible in particular to obtain a reduction in the cycle time.

Typically, the first tool is a gripper tool of at least one cell element, intended to engage with a cell element to extract it from the cell, and in which the second tool is an intervention tool on the cell. electrolytic bath. The fact that the upper portion of the elevation system is fixed on the carriage does not exclude that is provided at the interface of said upper portion and the carriage a device allowing a small degree of freedom in rotation about the X axis and / or the Y axis of said upper portion relative to the carriage. Such limited flexibility can reduce damage in the event of an impact, for example.

It can further be provided that the elevation system is shaped so that, in the upper position of the intermediate and lower portions, the first and second tools are in a storage position located higher than the first and second zones of action. For example, the two storage positions (namely that of the first tool and that of the second tool) are located substantially at the same altitude in Z.

The service module may further include:

an actuator designed to cause the displacement of the intermediate portion relative to the upper portion, said actuator having a portion fixed on the upper portion and a portion fixed in the lower portion of the intermediate portion; - And / or an actuator designed to cause the displacement of the lower portion relative to the intermediate portion, said actuator having a portion fixed in the lower portion of the intermediate portion and a portion fixed in the lower portion of the lower portion.

This prevents the actuator is covered when the different portions are in the high position.

According to a first embodiment, the upper guide axis and the lower guide axis are substantially merged.

Thus, for example, the elevation system comprises a telescopic mast, the lower portion being slidably mounted within the intermediate portion, and the intermediate portion being slidably mounted within the upper portion.

It can then be provided that the first tool is a bonnet gripper, and / or that the second tool is a cleaning tool of the cell, such as a shovel. Advantageously, the cleaning tool of the tank is shaped to collect the waste present in the tank and evacuate via the service machine, and not only to skim the surface of the electrolytic bath.

According to one possible embodiment, in projection in a horizontal plane (X, Y), the first action zone comprises at least two disjoint parts, and the second action zone is located between said two parts of the first action zone. . In this case, it can be provided that the service module comprises stop means designed to stop the downward movement of the lower portion relative to the intermediate portion when the first tool is in the process of intervention, so as to avoid interference between the first and second tools, and / or between a tool and a part of a cell of a cell (for example a hood or a tank wall). This stop means may for example comprise a stop or sensor.

According to a second embodiment, the upper guide axis and the lower guide axis are distinct and offset from one another. In other words, these two guide axes are parallel but offset in a direction parallel to a plane (X, Y), for example in the direction (X) or in the direction (Y).

According to one possible embodiment, the intermediate portion is slidably mounted inside the upper portion, and the lower portion is slidably mounted relative to the intermediate portion, outside the intermediate portion. There are thus two parallel telescopic masts but of distinct axes.

It can then be provided that the first tool is an anodic assembly gripper and / or that the second tool is a tool for breaking the crust that forms during electrolysis. Furthermore, the anodic assembly gripper can be shaped to also be able to grasp a containment bell.

In this case, the service module may furthermore include:

means for moving the tool to break the crust with respect to the carriage, substantially vertically downwardly, to bring said tool into contact with the crust;

means for moving the tool to break the crust in a substantially horizontal translation relative to the carriage, for producing a break line along at least one vertical side of the spent anode;

and shaped guiding means for guiding said translational displacement substantially horizontal relative to the tool carriage to break the crust.

Thus, it provides a service module that is designed to allow simple movements of the tool to break the crust, namely vertical movement and horizontal movement. The service module is therefore of a much simpler and more robust design than in the prior art.

For the realization of the breaking line, it can be provided to previously move the tool to break the crust to the right of the anode to disengage, in particular by moving the carriage carrying the service module. Then it's the tool that moves in relation to its support, according to simple movements, and not the support that is animated by complex articulation movements.

This results in greater ease of implementation of the tool, and the time required to achieve the breaking line can be significantly reduced.

Moreover, the use of simple movements of the tool makes it possible to envisage automation, which consequently solves the aforementioned problems related to the intervention of an operator.

In addition, the invention makes it possible to provide a better quality break line, in particular as regards its positioning relative to the anode to be disengaged, since this positioning is effected by simple movements, leading to lesser inaccuracies. .

The tool can thus make, on at least a portion of the periphery of the spent anode, a rupture line sufficient to allow the subsequent removal of the anode assembly from the vessel. This rupture line may be located along at least one vertical side of the spent anode, for example along each of two parallel vertical sides of the spent anode.

According to one embodiment, the service module comprises two tools for breaking the crust. The two tools are arranged vis-à-vis in substantially parallel planes, being spaced from each other by a distance (DY) greater than the dimension (dY) of an anode in the longitudinal direction ( X) or the transverse direction (Y), so as to produce two rupture lines on either side of the anode. Thus, the crust is broken more efficiently.

In a first example, the crust breaking tool, or at least one of the tools for crust breaking, includes a rotatable disc capable of cutting the crust. More specifically, the rotating disc has an axis extending substantially horizontally, is rotated about its axis, and is driven in translation in a substantially horizontal direction and orthogonal to said axis. The service module then further comprises means for rotating the rotating disk about its axis.

With such a tool, circular saw type, the break line is a continuous line, obtained by cutting the crust rather than breaking it. The line of rupture is therefore clear, which limits the formation of crustal blocks falling to the bottom of the tank and facilitates the insertion of a cleaning tool of the tank, for example a bucket bucket, and the installation of a new anode assembly. This is even more advantageous if it is a change of anode in automatic mode, as this limits the risks of interruption of the automatic cycle. In addition, the line of rupture being at least partly continuous, and not formed of a succession of distinct points, it constitutes a more important zone of weakness. Therefore, it is conceivable to make a break line on a smaller distance to the periphery of the spent anode, without making it more difficult to tear the worn anode assembly. The time required for these operations is therefore reduced.

According to this first example, the service module may further comprise means for rotating the rotating disk about its axis comprising a motor and a transmission system. The motor is preferably located at a distance from the rotating disk, that is to say deported away from the cutting zone, thus remote from the tank. This is advantageous in terms of arrangement. Indeed, the power to be provided for the cutting operation is relatively high, for example of the order of 15 to 30 kW. An engine of such power has a significant size and is therefore difficult to accommodate in the available internal volume of the tank. It can for example be an electric motor or a hydraulic motor. The transmission system includes, for example, angle deflectors and rigid or flexible transmission shafts.

In addition, the service module may comprise a compressed air blowing ramp for cooling the rotating disc during cutting of the crust.

Such circular saw type tool can be mounted on a remote axis of rotation, to rotate by 90 ° the plane in which is disposed the rotating disc when it is at the end of horizontal translation travel. Thus, it is possible with this tool to make a break line over the entire periphery of the spent anode.

According to a second exemplary embodiment, the tool for breaking up the crust, or at least one of the tools for breaking the crust, comprises a piercer arranged substantially vertically and means for displacing the breaker in a reciprocating movement along a substantially vertical direction, between a low position where the breaker penetrates at least part of the crust and a high position where the breaker is located above the crust, the means for moving said breaker in a substantially horizontal translation being designed to move the crust piercer when it is in high position.

The rupture line is then a succession of point breaks in the crust. Of course, the rupture line is sufficiently long and / or the point breaks are sufficiently close together to allow subsequent removal of the anode assembly. This type of tool is advantageous in that it is simple in design and low cost. A service machine is also proposed for operating an igneous electrolysis aluminum production plant, the installation comprising cells which contain anode assemblies and which are closed off by covers, the service machine comprising :

a carriage for mounting on a traveling crane, the traveling crane extending in a transverse direction (Y) and being adapted to move in a longitudinal direction (X) above the cells, the carriage being arranged to be able to moving relative to the crane in the transverse direction (Y) and to be positioned above and to the right of each of the hoods of the cells;

and a service module as previously described, the service module being mounted on the carriage.

Thus, the invention relates to a unit for operating an igneous electrolysis aluminum production plant, the plant comprising cells that contain anode assemblies immersed in an electrolytic bath, said cells being closed by covers, the unit comprising a structure comprising:

a traveling crane having two beams extending in a transverse direction (Y) and which is adapted to move in a longitudinal direction (X) above the cells;

and a service machine as previously described.

The invention further relates to an igneous electrolysis aluminum production plant, comprising:

a building in which several cells are located; each cell extending in a transverse direction (Y), the cells being arranged next to each other in a longitudinal direction (X) by providing at one of their ends a longitudinal operating aisle; each cell may contain a plurality of anode assemblies each including at least one anode and one anode rod; each cell having an opening that can be closed by a succession of removable covers;

a unit as previously described, the traveling crane being mounted longitudinally movable on longitudinal rails formed in the vicinity of two transverse end walls of the building.

According to a possible embodiment, each cell may contain several anode assemblies, for example substantially in their entirety, and the opening is a upper opening of the cell, located in a substantially horizontal plane, each of the covers being located in line with an anode assembly contained in the cell.

In this installation where the cells open from above, and not laterally, the invention is even more advantageous. Indeed, the various interventions on the cell can be done above, or even right, of the area of intervention, which simplifies the movement of the tools from and to the cell. The tools can for example be moved by a simple telescopic movement of the mast that carries them. In addition, since the anode assemblies do not protrude above the opening of the cells, the movement of the tools over the cells is not impeded, and the tools can thus easily be placed in proximity to any hoods of the cell, a hood defining a zone of intervention. In addition, such a configuration makes it easier to automate steps of different interventions on the cells,

Finally, the invention furthermore relates to a method of operating an igneous electrolysis aluminum production plant, the installation comprising cells which contain anode assemblies and which are closed by covers, the method using a unit comprising a structure comprising:

a traveling crane extending in a transverse direction (Y) and adapted to move in a longitudinal direction (X) above the cells;

- and a service machine comprising:

A carriage mounted on the traveling crane and arranged to be able to move relative to the crane in the transverse direction (Y) and to be positioned above and to the right of each of the hoods of the cells;

A service module mounted on the carriage and comprising an elevation system which comprises an upper portion fixed to the carriage and handling and intervention tools including a first tool and a second tool;

According to a general definition of the invention, the method comprises the steps of:

moving the service machine so that the first or the second tool is located at the right of a part of a cell hereinafter called the intervention zone;

actuating the elevating means so that the first tool can perform an intervention in a first action zone and / or the second tool can perform an intervention in a second action zone; said first and second action zones being located at or near the intervention zone, and being further distinct and located at a distance from one another:

projecting in a horizontal plane (X, Y) parallel to the longitudinal direction (X) and the transverse direction (Y);

and in the vertical direction (Z), the first action zone being higher than the second action zone.

According to one possible embodiment, the first and second tools intervene in their respective zones of action at different times. As a variant, the first and second tools intervene in their respective zones of action at least partly simultaneously.

The method can use a service machine whose elevation system comprises: an intermediate portion movable relative to the upper portion along a substantially vertical upper guide axis, between a high position and a low position, the intermediate portion; carrying the first tool for performing an intervention in the first action zone, in the lower position of the intermediate portion;

a lower portion movable relative to the intermediate portion along a substantially vertical lower guide axis, between a high position and a low position, the lower portion carrying the second tool for performing an intervention in the second action zone in the lower position of the lower portion.

In this case, the method may comprise the following successive steps:

the intermediate portion is displaced relative to the upper portion, the lower portion remaining fixed relative to the intermediate portion and therefore being driven by the same movement as the latter relative to the upper portion;

then the lower portion is moved relative to the intermediate portion.

A variant of this sequential operation consists of a simultaneous operation, in which the displacement of the intermediate portion relative to the upper portion and the displacement of the lower portion relative to the intermediate portion are at least partly simultaneous.

For example, the intervention in the first action zone includes gripping a hood by means of a hood gripper, as the first tool, and the intervention in the second action zone comprises cleaning the cell by means of a cell cleaning tool, as a second tool.

According to another possible embodiment, the intervention in the first action zone comprises the gripping of an anode assembly by means of an anodic assembly gripper, as a first tool, and the intervention in the second zone of action. action includes breaking the crust that forms during electrolysis by means of a crust breaking tool, as a second tool.

When the second tool is a crust breaking tool, the elevating means can be actuated so that the crust breaking tool is moved relative to the carriage substantially vertically downward to bring the tool into contact with the crust. crust. The crust breaking tool can then be moved in a substantially horizontal translation to provide a break line along at least one vertical side of the spent anode. The tool is thus moved to break the crust on at least a portion of the periphery of the spent anode, to provide a breaking line sufficient to allow subsequent removal of the anode assembly from the vessel.

When two tools for the crust are used, two rupture lines (on either side of the anode can be produced simultaneously) The two rupture lines can advantageously be parallel to the longitudinal direction (X).

In addition, when the first tool is an anodic assembly gripper mounted on the same support as the tool for breaking the crust, the anode assembly can be gripped by means of the anode assembly gripper before putting the tool to breaking the crust in contact with the crust, so as to ensure a good positioning of said tool relative to the anode to be disengaged.

When using a rotating disc, as a tool for breaking the crust, the rotating disc has an axis extending substantially horizontally and being rotated about its axis. And the method further comprises moving the rotating disk in a substantially horizontal direction and orthogonal to said axis, so that the break line forms a continuous cut. When using a piercer arranged substantially vertically, as a tool for breaking the crust, the method further comprises the displacement of the breaker reciprocating along a substantially vertical direction, between a low position where the breaker penetrates at least part of the crust and a high position where the pierter is located above the crust, the displacement of the breaker in a substantially horizontal translation being performed when the breaker is in the high position.

Several possible embodiments of the invention are now described by way of nonlimiting examples, with reference to the appended figures:

Figure 1 is a schematic perspective view of an aluminum production plant according to one embodiment of the invention, showing a unit including a carriage carrying tools;

Figures 2a, 2b and 2c respectively illustrate an upper portion, an intermediate portion and a lower portion of an elevation system according to a first embodiment;

Figures 3a and 3b show the elevation system of Figures 2a-2c in the mounted position, respectively when the intermediate and lower portions are in the upper position, and when said portions are in low position;

Figures 4a and 4b schematically illustrate a variant of the elevation system of Figures 2a to 3b, in two different orientations;

FIGS. 5a to 5d diagrammatically illustrate various interventions carried out on the installation by means of one or the other of the tools of the elevation system according to the first embodiment;

FIGS. 6a and 6b illustrate an elevation system according to a second embodiment, according to two different orientations, the second tool being a rotating disc;

FIG. 7 schematically represents a tank of the installation, seen from above, and shows two rupture lines formed on either side of an anode assembly used by means of a rotating disk;

FIGS. 7a to 7c illustrate various interventions carried out on the installation by means of one or other of the tools of the elevation system according to the second embodiment of FIGS. 6a and 6b;

FIGS. 8a to 10b illustrate successive steps of a method for disengaging a spent anode assembly from a tank of an installation, by means of the rotary disc illustrated in FIGS. 6a and 6b;

FIGS. 11a and 11b illustrate an elevation system according to a second embodiment, according to two different orientations, the second tool being a stitcher; Figures 12a to 15b illustrate successive steps of a method for disengaging a spent anode assembly from a tank of an installation, by means of the rotating disc illustrated in Figures 6a and 6b;

FIG. 16 diagrammatically represents a tank of the installation, viewed from above, and shows two rupture lines made on either side of an anode assembly used by means of a piercer;

Figures 17 and 18 illustrate alternative embodiments of rupture lines around a spent anode assembly, by means of the method according to the invention.

FIG. 1 schematically represents a plant 1 for producing aluminum by electrolysis, and more particularly an electrolysis room of such an installation 1.

The installation 1 comprises a building in which are located several electrolysis cells 2. Each cell 2 extends in a transverse direction Y, and the cells 2 are arranged next to each other in a longitudinal direction X. Between two adjacent cells 2 is provided a transverse access path 4, and to one ends of the cells 2 is formed a longitudinal operating aisle 5 along the installation 1.

Each cell comprises a tank 6 having two longitudinal walls 7 and two transverse walls 8, and containing a cathode and an electrolytic bath. The tank 6 has an upper opening 9 located in a substantially horizontal plane. Each cell further comprises one or more covers 10 provided to seal the opening 9 removably. In the embodiment shown, the covers 10 are substantially planar and rectangular. Each cover 10 extends substantially in a horizontal plane, from a transverse wall 8 of the tank 6 to the opposite transverse wall 8, several covers 10 being juxtaposed along the direction Y to allow, together, to seal 9. Each cover 10 is provided with parts 11 that can be grasped in order to remove the cover 10. It should be noted that the arrangement of the parts 1 1 on the covers 10 as shown in FIG. 1 should not be considered as limiting.

In the tank 6 are placed several anode assemblies 15. An anode assembly 15 comprises at least one anode 16 in the form of a precooked carbon block, which will be immersed in the electrolytic bath. An anode rod 17 is sealed in the anode 16, all the rods 17 being fixed on the same anodic support 18. In the embodiment shown, an anode assembly 15 comprises four anodes 16 and has a rectangular parallelepipedal shape, which is placed in the tank so as to extend substantially to the right of a single cover 10. The tank 6 and the anode assembly 15 are configured so that the anode assembly 15 can be housed substantially in its entirety in the tank 6, at least so that it does not protrude above the opening 9.

The tank 6 receives new anode assemblies 15, that is to say carrying new anodes 16a. During electrolysis, the anodes are gradually consumed and become used anodes 16b or butts (see Figure 5a in particular). An anode assembly 15 worn, that is to say carrying a used anode 16b, must be removed from the tank 6 to be replaced by a new anode assembly 15.

In particular, to carry out the anode assembly change operations 15, the installation 1 comprises a unit 30, or service unit.

The unit 30 comprises a crane 31 which comprises two beams 32 extending in the transverse direction Y. The crane 31 is mounted longitudinally movable on longitudinal rails formed in the vicinity of two transverse end walls 3 of the building. The crane 31 is thus designed to move in the longitudinal direction X above the cells 2 and the operating aisle 5.

The unit 30 also comprises a service machine 33. The service machine 33 comprises a carriage 35 mounted on the two beams 32 of the traveling crane 31, movable in the transverse direction Y. The carriage 35 is thus arranged to be able to be positioned above and to the right of each of the hoods 10 of the cells 2. The service machine 33 further comprises a service module 36 mounted on the carriage 35 and having handling and intervention tools. It is specified that, in Figure 1, these tools are shown very schematically.

The unit 30 may further comprise at least one support 50 which is assembled to the traveling crane 31 or to the carriage 35, suspended therein, and movably in translation in the transverse direction Y with respect to the carriage 35.

The support 50 is designed to receive, temporarily, at least one element belonging to or intended to belong to a cell 2 - such as a new or worn anode assembly 15, a cover 10 or waste electrolysis - and / or or equipment intended to interact with said element for the operation of the cell 2 - such as a pallet 300 receiving an anode assembly 15, a containment bell for an anode assembly 15 or a waste bin 500. In FIG. 1 , the pallet 300 is illustrated very schematically.

Alternatively, the unit 30 may comprise at least one support 80 shaped to be able to be placed on a cell 2. Such a support 80 may comprise a plate 81 and support means, such as feet 82, so that the support 80 can rest stably above the vessel 6, preferably in the vicinity of an intervention zone. The tools of the service module 36 are mounted on the carriage 35 so as to be placed in a high position in which they do not interfere with the displacement in transverse translation of the support 50, including when the support 50 receives one of said elements and / or one of said equipment.

According to the invention, the service module 36 comprises an elevation system which comprises an upper portion intended to be fixed to the carriage and handling and intervention tools. In the embodiment shown, the tools carried by the service module 36 are distributed in a first tool block 100 and a second tool block 200.

In general, the elevation system further comprises a movable intermediate portion carrying a first tool intended to perform an intervention in a first action zone, and for example an intervention consisting in removing an element from the vessel, and a portion lower mobile carrying a second tool for performing an intervention in a second zone of action, and for example an intervention consisting of intervening on the electrolytic bath. According to the invention, the first and second zones of action are distinct and located at a distance from each other both in projection in a horizontal plane (X, Y) and in the vertical direction (Z), the first action zone being higher than the second action zone.

By zone of action, here is defined the portion of the space likely to be occupied by the tool during operation in all its positions.

Reference is first made to FIGS. 2a to 5d, relating to a first embodiment of the invention. In concrete terms, this first embodiment may relate to the first tool block 100.

The first tool block 100 illustrated in FIGS. 2a to 3b comprises a first telescopic mast 1 1 1 in the vertical direction Z. The first mast 1 1 1 comprises:

an upper portion 1 12 fixed to the carriage 35;

an intermediate portion 1 13 movable relative to the upper portion 1 12 along a substantially vertical upper guide axis 1 14, between a high position and a low position, sliding inside the upper portion 1 12;

a lower portion 1 15 movable relative to the intermediate portion 1 13 along a lower guide axis 1 16 substantially vertical and coincides with the upper guide axis 1 14, between a high position and a low position, sliding inside the intermediate portion 1 13.

The fact that the first mast 1 1 1 is fixed on the carriage does not exclude that is provided at the interface of the mast and the carriage a device allowing a low degree of freedom in rotation around the X axis and / or the Y axis of the mast relative to the carriage. Such limited flexibility can reduce damage in the event of an impact, for example.

In the embodiment shown, the upper portions 1 12, intermediate 1 13 and lower 1 15 are cylindrical, of polygonal section (for example substantially square), or round. Alternatively, they could be formed of an open profile, for example a U-shaped profile.

There are further provided guiding devices 131, 132, 133, 134 of the different portions 1 12, 1 13, 1 15 relative to one another in their relative Z sliding movement, for example in the form of rollers. / or inner or outer guide pads.

The intermediate portion 1 13 carries a first tool for performing an intervention in a first action zone 161, in the lower position of the intermediate portion 1 13. The first tool here is a hood gripper 101 and more precisely in the mode of embodiment shown two hood grippers 101. Concretely, it can be provided a spar 102 fixed in the lower part of the intermediate portion 1 13, the spar 102 extending in the longitudinal direction X on either side of the intermediate portion 1 13, and bearing to each its longitudinal ends a hood gripper 101. In other words, in projection in a horizontal plane (X, Y), the first action zone 161 comprises two disjoint parts 161a and 161b.

It is specified that the hood gripper 101 must be arranged to cooperate with the parts 1 1 of the cover 10. In other words, the hood gripper 101 and the parts 1 1 must correspond in shape and the arrangement in space. Thus, with hood grippers 101 disposed substantially at the longitudinal ends of the spar 102, as illustrated in FIG. 2a, the parts 1 1 must be situated substantially at the longitudinal ends of the hoods 10 and not in a more centered manner as represented by FIG. example in Figure 1.

The lower portion 1 15 carries a second tool for performing an intervention in a second action zone 162, in the lower position of the lower portion 1 15. The second tool here is a cleaning tool 120 of the cell, involved in the electrolytic bath. The cleaning tool 120 is for example in the form of a bucket bucket. In the embodiment shown, the cleaning tool 120 is disposed substantially in the axis of the mast 1 1 1, the second action zone 162 is therefore located on this axis 1 14, 1 16. In other words, in projection in a horizontal plane (X, Y), the second action zone 162 is here located between the two disjunct parts 161a and 161b of the first action zone 161. In addition, actuators are provided to cause the displacement of the different portions relative to each other. It can be hydraulic cylinders, pneumatic or electric.

In the embodiment shown, a first actuator 135 is fixed on an attachment lug 1 17 integral with the lower part of the upper portion 1 12 of the mast 1 1 1 and acts on the spar 102. In addition, a second actuator 136 is fixed on a bracket 1 18 secured to the lower part of the intermediate portion 1 13 of the mast 1 1 1 and acts on an attachment lug 1 19 integral with the lower portion of the lower portion 1 15 of the mast 1 1 1.

A third actuator 137 is arranged in the lower part of the lower portion 1 15 of the mast 1 1 1, to cause the opening and closing of the cleaning tool 120, in the case of a scoop-type mechanism.

The first mast 1 1 1 is shown in the assembled state in Figures 3a and 3b.

In Figure 3a, the mast 1 1 1 is in fully retracted position, that is to say that the intermediate portion 1 13 and the lower portion 1 15 are both in the up position. The first and second tools 101, 120 are then in a storage position 163 located higher than the first and second action zones 161, 162. Moreover, as seen in FIG. 3a, nor the actuators 135, 136, 137 and the lugs 1 17, 1 18, 1 19 are covered by one or the other of the portions 1 12, 1 13, 1 15.

In Figure 3b, the mast 1 1 1 is in fully deployed position, that is to say that the intermediate portion 1 13 and the lower portion 1 15 are both in the low position.

As seen both in FIG. 3a and FIG. 3b, the first and second action zones 161, 162 are distinct. In addition, they are located at a distance from each other: - both in projection in a horizontal plane (X, Y), and more precisely, in the embodiment shown, along the longitudinal direction X ;

and in the vertical direction (Z), the first action zone 161 being higher than the second action zone 162.

According to a variant of this first embodiment, diagrammatically illustrated in FIGS. 4a and 4b, the first tool block 100 comprises two first masts 1 1 1a, 1 1 1b, which are telescopic in the vertical direction Z. masts 1 1 1 a, 1 1 1 b have parallel but distinct axes, that is to say shifted in a plane (X, Y). Each of the first masts 1 1 1 a, 1 1 1 b comprises an upper portion 1 12 fixed to the carriage 35, an intermediate portion 1 13 sliding inside the upper portion 1 12 and a lower portion 1 15 sliding to the inside the intermediate portion 1 13.

A spar 102 connects the two intermediate portions 1 13 of the first masts 1 1 1 a, 1 1 1 b, and has at each of its longitudinal ends a hood gripper 101 for performing an intervention in a first action zone 161, respectively in disjoint parts 161a and 161b.

Each of the lower portions 1 15 of the first masts 1 1 1 a, 1 1 1 b carries a cleaning tool 120 of the cell for performing an intervention in a second zone of action 162, located in the axis of the first mast 1 1 1 corresponding, therefore between the two disjoined parts 161a and 161b of the first action zone 161, in projection in a horizontal plane (X, Y).

As illustrated in Figures 5a to 5d, the invention allows, with a single elevation system carrying two tools 101, 120 involved in different action areas 161, 162, to perform different interventions. FIGS. 5a to 5d show steps of a removal operation of a spent anode assembly 15, that is to say having at least one used anode 16b, prior to its replacement by an anode assembly 15 nine. This used anode assembly 15 is located in the tank 6, in an intervention zone 600 of the cell 2, initially covered by a cover 10 situated above and to the right of the used anode assembly 15.

In FIG. 5a, the cover 10 is in place on the tank 6, the carriage 35 is placed so that the first tool block 100 is located in the vicinity of the intervention zone 600, the tools - namely the the hood grippers 101 and the cleaning tool or tools 120 - being in the storage position 163.

In Figure 5b, the intermediate portion 1 13 of the first masts 1 1 1 a, 1 1 1 b is in the low position, but the lower portion 1 15 is in the high position. The hood gripper 101 is in its first action zone 161, at the level of the parts 1 1 by which the cover 10 can be entered, to the right of the intervention zone 600. On the other hand, there is a game 165 between the cover 10 and the cleaning tool 120, avoiding interference between these two elements during the step of gripping the cover 10.

The cover 10 can then be raised, by an upward movement of the intermediate portion 1 13 with respect to the upper portion 1 12 of the masts 1 1 1 a, 1 1 1 b, as shown in Figure 5c. The cover 10 is then deposited, for example on a cover adjacent to the intervention zone 600, or on a support 50, 80. Once the spent anode assembly has been removed by the action of other tools, the cleaning step of the tank 6 can be carried out at the intervention zone 600, as illustrated in FIG. 5d. The masts 1 1 1 a, 1 1 1 b are then placed in their fully extended position, so that the cleaning tool 120 can intervene at the bottom of the tank 6, in its second zone of action 162 located lower than the first action zone 161, in the intervention zone 600. In this configuration, the hood gripper 101 is located above the tank 6 and does not interfere with the intervention of the cleaning tool 120. In order to avoid any risk of collision with the tank 6, and in particular the transverse walls 8, stops or sensors may be provided to stop the stroke of the intermediate portion 1 13.

Thus, in FIGS. 5a to 5d, the first and second tools 101, 120 intervene in their respective zones of action 161, 162 at different times.

Referring now to Figures 6a to 15b, relating to two examples of a second embodiment of the invention. In concrete terms, this second embodiment can relate to the second block of tools 200.

The second tool block 200 illustrated in Figures 6a and 6b comprises a second telescopic mast 21 1 in the vertical direction Z, and two second masts 21 1 a, 21 1 b in the embodiment shown. Each of the second masts 21 1 a, 21 1 b comprises:

an upper portion 212 fixed to the carriage 35;

- An intermediate portion 213 movable relative to the upper portion 212 along a substantially vertical upper guide axis 214, between a high position and a low position, sliding inside the upper portion 212;

a lower portion 215 movable relative to the intermediate portion 213 along a substantially vertical lower guide axis 216 and distinct from the upper guide axis 214, that is to say shifted relative thereto. In the embodiment shown, the axes 214 and 216 are offset in the direction X and in the direction Y. The lower portion 215 is slidably mounted relative to the intermediate portion 213 outside the intermediate portion 213, between a high position. and a low position.

As previously, the fact that the second mast 21 1 is fixed on the carriage does not exclude that is provided at the interface of the mast and the carriage a device allowing a small degree of freedom in rotation about the X axis and / or the Y axis of the mast relative to the carriage. In the embodiment shown, the upper 212, intermediate 213 and lower 215 portions are cylindrical, of polygonal section (for example substantially square), or round. Alternatively, they could be formed of an open profile, for example a U-shaped profile.

Guiding devices 231, 232, 233, 234 of the different portions 212, 213, 215 are provided relative to one another in their relative Z sliding movement, for example in the form of inner or outer rollers. .

The intermediate portion 213 carries a first tool intended to perform an intervention in a first action zone 261, in the lower position of the intermediate portion 213. The first tool here is an anodic assembly gripper 201, also called tearing tool . If two anodic assembly grippers 201 are provided, the first action zone 261 has two disjoint portions 261a and 261b.

The lower portion 215 carries a second tool intended to perform an intervention in a second action zone 262, in the lower position of the lower portion 215. The second tool here is a tool for breaking the crust that forms during the electrolysis , acting on the surface of the electrolytic bath. This tool makes it possible to at least partially break the crust, so as to be able to disengage the spent anode assembly 15 from the crust and then extract it from the vessel 6.

According to the second embodiment, the service module 36 may further comprise:

means for moving the tool to break the crust with respect to the carriage 35, substantially vertically downwards, to bring said tool into contact with the crust and to penetrate it at least partially into the crust;

means for moving the tool to break the crust with respect to the carriage 35 in a substantially horizontal translation, for producing a break line 380 along at least one vertical side of the used anode 16b;

and guide means 230 shaped to guide said movement in substantially horizontal translation of the tool to break the crust.

The mast 21 1 forms a support for the tool to break the crust which is mounted on the carriage 35 forming a mobile equipment installation 1.

According to a first example, illustrated in particular in FIGS. 6a to 10b, this tool may be in the form of a rotary disk 220 capable of cutting the crust in the manner of a circular saw. The rotating disc 220 has an axis 221 extending substantially horizontally. In the embodiment shown, the rotary disk 220 is arranged substantially in the axis of the lower portion 215, and extends in a vertical plane (X, Z), with its axis 221 oriented along the axis (Y). The second action zone 262 is thus located at least partly on the lower guide axis 216. If two rotary discs 220 are provided, on either side according to Y of the upper guide axis 214, as one as can be seen in FIG. 6b, the second action zone 262 has two disjoint parts 262a and 262b.

The rotating disc 220 may be made of metal and have a thickness greater than 6 mm, for example of the order of 7 mm. The rotating disc 220 may comprise at its periphery a plurality of rigid teeth, preferably substantially regularly spaced apart, said teeth having diamond elements reported and welded to the laser. In addition, there can be provided a protective device 223, in the form of a cap of the upper part of the rotary disc 220, to prevent projections during the implementation of the rotary disc 220.

In operation, the rotating disc 220 is rotated about its axis 221, in order to cut the crust. The means for rotating the rotating disk 220 around its axis 221 comprise a motor located at a distance from the rotary disk 220 and a transmission system (not shown).

The connection system between the rotary disc 220 and the carriage 35 may comprise a clamping jaw of the central portion of the rotary disc 220. Preferably, for a better mechanical strength, the nip is made at a relatively central portion large area, for example having a radius greater than one quarter of the radius of the rotating disk, to limit the risk of buckling of the rotating disk 220.

In addition, the connection system may comprise a compressed air blowing ramp to cool the rotating disk 220 during cutting of the crust.

In the embodiment shown, the lower portion 215 carries, as seen in Figure 6b, the two rotary discs 220 disposed substantially parallel, vis-à-vis their axes 221 being substantially merged. In addition, the two rotary disks 220 are arranged on either side along Y of the upper guide axis 214, being spaced from each other by a distance DY greater than the dimension dY of anode. 16 - or anodes 16 of the same anode assembly 15 - in the transverse direction (Y) (see FIG. 7c).

Similarly to the first embodiment, a first actuator 235 allows the displacement of the intermediate portion 213 relative to the upper portion 212, and a second actuator 236 allows movement of the lower portion 215 relative to the intermediate portion 213. It can be hydraulic cylinders, pneumatic or electric.

According to the invention, there is further provided means for moving the axis 221 of the rotary disk 220 relative to the carriage 35 in a substantially horizontal translation and orthogonal to said axis 221, and guiding means shaped to guide said displacement by translation of the axis 221 of the rotary disk 220.

According to an embodiment illustrated in particular in Figures 6a and 6b, the translation is performed in the longitudinal direction (X). For this purpose are provided two longitudinal guide rails 230 fixed on the intermediate portion 213 and receiving integral members of the lower portion 215. In the embodiment shown, the two rotary discs 220 can be linked in their translational movement, this is not necessary. being not limiting. The two rotating discs 220 can act simultaneously to each perform a cut of the crust.

As illustrated in the figures, the invention makes it possible, with a single elevation system carrying two tools 201, 220 involved in different action zones 261, 262, to perform different interventions. FIGS. 7a to 10b show steps of a removal operation of a spent anode assembly, that is to say having at least one used anode 16b, prior to its replacement by an anode assembly 15 nine. This used anode assembly is in the tank 6, in an intervention zone 600 of the cell 2.

In FIGS. 7a to 10b, steps of an operation of removal of a spent anode assembly 15, that is to say having at least one used anode16b, prior to its replacement by an anode assembly 15 are shown. new. This used anode assembly is in the tank 6, in an intervention zone 600 of the cell 2.

In FIG. 7a, the carriage 35 is placed so that the second tool block 200 is in line with the intervention zone 600, the tools - namely the anodic assembly gripper (s) 201 and the one or more rotating discs 220 - being in the storage position 263.

In FIGS. 7b and 7c, the intermediate portion 213 of the second masts 21 1 a, 21 1 b is in the lower position, but the lower portion 215 is in the high position. The anodic assembly gripper 201 is in its first action zone 261, at the level of the anodic support 18 by which the anode assembly 15 can be grasped, in line with the intervention zone 600. Specifically, the grippers anodic assembly 201 are at the right of the corresponding gripping members arranged on the support 18, and the rotating discs 220 are at the right of the 240 transverse spaces existing between the anode assembly 15 located in the intervention zone 600 and adjacent anode assemblies 15 (Figure 7c). In addition, the rotating discs 220 are located substantially at a longitudinal end of the guide rails 230, which substantially corresponds to a longitudinal end of the spent anode assembly.

In addition, in FIGS. 7b and 7c, the lower portion 215 is in the high position. The anodic assembly gripper 201 is thus in a position such that it can come to grip the anodic support 18. This makes it possible to correctly position, in the transverse direction Y, the rotary discs 220 at the right of the spaces 240. Advantageously, the The anodic assembly gripper 201 can then be engaged with the anodic support 18, so as to ensure the correct positioning of the rotating disc 220.

Without additional position adjustment, the lower portion 215 is then lowered, so that the rotating disc 220 to break the crust can reach the second action zone 262 (FIGS. 8a and 8b), that is to say that the rotating disc 220 comes into contact with the crust and penetrates at least partially into the crust. In the embodiment shown, the rotating disc 220 - or each of the two rotary discs 220 - is movable along longitudinal guide rails 230, remaining substantially in its plane, so that said rotating disc 220 moves relative to the crust to make a cutting line 380 (Figure 7) continuous along the used anodes 16b, the cutting line 380 extending in the longitudinal direction (X). More precisely, the two rotary disks 220 simultaneously produce two rupture lines 380 on either side of the used anode (s) 16b, as illustrated in FIG. 7. Thus, the second action zone 262 also moves along of the X axis during this phase of disengagement of the spent anode assembly.

In this configuration, the rotary disc (s) 220 have been moved in the longitudinal direction (X) by being guided in the guide rails 230, remaining substantially in its plane, and being always rotated, until it reaches substantially the other longitudinal end of the guide rails 230, which corresponds substantially to the other longitudinal end of the used anode assembly 15 (Figures 9a and 9b). The rotary discs 220 then made a rupture line 380 sufficient to allow the spent anode assembly 15 to be disengaged from the vessel 6, by means of the anodic assembly gripper 201 raised by means of the mast 21 1 (FIGS. 10 and 10b). . Due to the quality of this break line 380, and also its continuous character on both sides of the spent anode 16b, it is not necessary, in order to disengage the spent anode assembly, to make a break line. on at least one of the other sides of the anode 16b. Prior to tearing and lifting the spent anode assembly, it may be necessary to separate the anode assembly 15 from an anode receiver 14 fixed to the cell 2 by means of a clamping member. release 245 mounted on the service module 36, on the lower portion 215. As illustrated in Figure 9a, this clamping / loosening member 245 can be deployed when used, and retracted the rest of the time (Figures 7a and 10a especially).

The anodic assembly gripper 201 engaged with at least one anode assembly 15 is then raised by actuating the first actuator 235 to raise the intermediate portion 213 relative to the upper portion 212 (Figures 10a and 10b). The rotating disc 220 - or the two rotating discs 220 - can be raised by actuating the second actuator 236 simultaneously or prior to the actuation of the first actuator 235.

Once the anode assembly 15 has been removed, the rotating disk 220 can be moved in translation to be returned to its initial position for use in a subsequent disengagement operation of another spent anode assembly.

According to a second example, illustrated in FIGS. 11a to 15b, the tool for breaking the crust comprises a stinger 270 arranged substantially vertically and reciprocated along a substantially vertical direction, between a low position and a high position.

It should be noted that FIG. 1 illustrates a tool for breaking the crust in the form of a rotating disc 220. However, this is a schematic illustration which is not limited to this embodiment and may include the breaker 270 as illustrated in FIGS. 11a to 15b.

Structurally, with the exception of the tool itself and the means for its vertical reciprocating movement, this second embodiment is similar to the first embodiment. The same elements therefore bear, in the drawings, the same references, and they will not be described again in detail.

FIGS. 11 to 15b show steps of an operation to remove an old anode assembly 15, that is to say having at least one used anode 16b, before it is replaced by a anodic assembly 15 new. This used anode assembly is in the tank 6, in an intervention zone 600 of the cell 2.

In FIGS. 11a and 11b, the carriage 35 is placed so that the second tool block 200 is located in the vicinity of the intervention zone 600. The stitches 270 are located substantially at one longitudinal end of the rails 230, at the right of the spaces 240 transverse existing between the anode assembly 15 located in the intervention zone 600 and the adjacent anode assemblies.

The anodic assembly gripper 201 is in a position such that, by lowering it, it can come to grip the anodic support 18, which makes it possible to correctly position, in the transverse direction Y, the breakers 270 at the spaces 240 between two adjacent anode assemblies.

The anodic assembly gripper 201 is then lowered, so as to come into contact with the anodic support 18, ensuring the correct positioning of the breakers 270.

Without additional positioning adjustment, the lower portion 215 is then lowered, as illustrated in Figures 12a and 12b, and the breaker 270 - or each of the two breakers 270 - is placed in the second action zone 262, in which the breaker 270 is able to come into contact with the crust.

Then, the breaker 270 - or each of the two breakers 270 - is reciprocated along a substantially vertical direction, between a low position where the breaker 270 penetrates at least part of the crust and a high position where the breaker 270 is located above the crust. In addition, the or each stinger 270 is moved along the longitudinal axis (X), being guided in the guide rails 230, until it reaches substantially the other longitudinal end of the guide rails 230 (FIGS. 13b). For questions of feasibility, the displacement of the breaker 270 according to the longitudinal translation is performed when the breaker 270 is in the up position. As seen in Figure 13a, the breaker 270 follows a path 271 in the form of successive jumps.

The breaker 270 thus makes a break line 380a along a vertical side of the used anode 16b, the break line 380a extending in the longitudinal direction (X). More precisely, the two breakers 270 simultaneously produce two break lines 380a on either side of the used anode (s) 16b, as illustrated in FIG. 16.

The seamer (s) 270 have produced a rupture line 380a in the form of point breaks spaced from one another. This break line 380a is sufficient to allow the spent anode assembly 15 to be disengaged from the vessel 6, by means of the anodic assembly gripper 201 raised via the mast 21 1 (FIGS. 12a and 12b). It is generally not necessary, to disengage the spent anode assembly, to provide a break line on at least one of the other sides of the anode 16b.

Prior to tearing and lifting the spent anode assembly, it may be necessary to separate the anode assembly 15 from the anode receiver 14 by means of the clamping / loosening member 245 mounted on the service module 36. The lower portion 215 is then raised relative to the intermediate portion 213 by actuating the second actuator 236 and, simultaneously or in a second step, the intermediate portion is raised relative to the upper portion 212 by actuating the first actuator 235, so that the anodic gripper 201 engaged with the anode assembly 15 is raised.

Once the anode assembly 15 has been removed, the stinger 270 can be moved in translation to be returned to its original position for use in a subsequent disengagement operation of another spent anode assembly.

Referring now to Figures 17 and 18 which illustrate alternative embodiments of rupture lines around a worn anode assembly, by means of the method according to the invention.

In FIG. 17, only two rupture lines have been made on either side of the used anode 16b. One of the lines is a continuous break line 380, and the other of the lines is a discontinuous break line 380a. This involves the use of a service module 36 comprising two different tools for breaking the crust, namely on the one hand a rotating disc 220 and on the other hand a stitcher 270.

Moreover, although, thanks to the invention, it is generally sufficient to produce a breaking line - continuous 380 or discontinuous 380a - along two opposite faces of the used anode 16b, variations are possible, as illustrated on Thus, on the one hand, there are two continuous crust rupture lines 380 along two opposite faces of the used anode 16b - here oriented along (X) - and on the other hand two rupture lines. 380a discontinuous, along two other opposite faces of the used anode 16b - here oriented along (Y).

It should be noted that it is also conceivable to make only two rupture lines, on either side of the used anode 16b, but with breaking lines oriented in the transverse direction (Y).

Other configurations of the different break lines, not shown, are also possible.

As can be seen by comparing FIGS. 7a to 10b of the first example and comparing FIGS. 12a to 15b of the second example, there are first and second action zones 261, 262 which are distinct and situated at a distance from each other. the other both in a horizontal plane (X, Y) and in the vertical direction (Z). In addition, the storage position 263 is located higher than the first and second action zones 261, 262. In addition, when the anode gripper 201 is lowered by the actuation of the first actuator triggering the vertical downward movement of the portion 213 intermediate with respect to the upper portion 212, the rotating disc 220 or the breaker 270 - or each two rotary discs 220 or each of two lancers 270 - are then prepositioned automatically to the right space 240 between two adjacent anode assemblies 15. Indeed, since the anodic assembly gripper 201 is correctly placed to grip the anode carrier 18, the rotating disc 220 or the breaker 270 is also correctly positioned to break the crust. Consequently, the positioning errors of the rotating discs 220 or the stitches 270 are reduced, favoring the automation of all the operations of the anodic assembly change 15.

Furthermore, it may be noted that, in this embodiment, the first and second tools 201, 220 intervene in their respective zones of action 261, 262 at least partly simultaneously. Indeed, in the step illustrated in FIG. 7c, in particular for the rotary disc 220 and in FIG. 13b in particular for the breaker 270, the anodic assembly grippers 201 are active at the same time as the rotary disc 220 or the breaker 270 is active.

In general, the invention makes it possible to use as a first tool a gripping tool for a cell element, in this case a cover for the hood gripper or an anode assembly for the anode assembly gripper. , without the first tool, in engagement with the cell element, hindering or being by the second tool. The second tool can then advantageously be an intervention tool on the electrolytic bath, intended to be in contact with the bath, in this case with all that the bath can contain for the cleaning tool or with the crust formed in electrolytic bath surface for the tool to break the crust.

Thus, the invention provides a decisive improvement to the prior art, and has many advantages among which we can mention:

reducing the cycle time of the anode assembly change without the intervention of an operator on the ground to open the tank;

the compactness of the service module, in particular by a configuration of the "two tools in one" type, which enables the unit to be lightened and simplified, but also to limit the envelope of the electrolysis building;

the correct positioning around the anode of tools to break the crust, resulting in a gain in the reliability and repeatability of the automation of operations (including the ease of introduction of the new anode between the two anodes adjacent) and on securing operations in automatic (a shift of (the) tool (s) could lead to damage to the anode or equipment on the tank);

reducing the effort required to extract the spent anode, thus generating less mechanical stress, especially for the gripping tool;

the limited cost of the service module, although the latter integrates more functions, due to the implementation of elevation systems common to several tools;

certain steps can be performed simultaneously and not sequentially; the limitation to the minimum of the opening time of the tank, that is to say "bare" bath, also due to the completion of steps simultaneously and not sequentially.

The invention is not limited to the embodiments described above as examples but includes all the technical equivalents and variants of the means described as well as their combinations.

Claims

1. Unit for operating an igneous electrolysis plant (1), the plant (1) comprising cells (2) which contain anode assemblies (15) immersed in an electrolytic bath, said cells being closed by covers (10), the unit (30) comprising a structure comprising:

a crane (31) which has two beams (32) extending in a transverse direction (Y) and which is adapted to move in a longitudinal direction (X) above the cells (2);

and a service machine (33), comprising: a carriage (35) for mounting on a traveling crane (31), the traveling crane (31) extending in a transverse direction (Y) and being adapted for moving in a longitudinal direction (X) above the cells (2), the carriage (35) being arranged to be able to move relative to the traveling crane (31) in the transverse direction (Y) and to be able to be positioned above and to the right of each of the hoods (10) of the cells (2);

o and a service module (36) mounted on the carriage (35); the service module (36) comprising at least one elevation system which comprises an upper portion (1 12, 212) attached to the carriage (35) and handling and intervention tools,

the unit being characterized in that the at least one elevation system further comprises:

an intermediate portion (1 13, 213) movable with respect to the upper portion (1 12, 212) along a substantially vertical upper guide axis (1 14, 214), between a high position and a low position, the intermediate portion (1 13, 213) carrying a first tool (101, 201) for performing an intervention in a first action zone (161, 261), in the lower position of the intermediate portion (1 13, 213);

a lower portion (1 15, 215) movable with respect to the intermediate portion (1 13, 213) along a substantially vertical lower guide axis (1 16, 216), between a high position and a low position, the lower portion (1 15, 215) carrying a second tool (120, 220, 270) for performing an intervention in a second action zone (162, 262), in the lower position of the lower portion (1 15, 215);

the elevation system being shaped so that the first and second zones of action (161, 162, 261, 262) are distinct and located at a distance from one another:

and / or in the vertical direction (Z), the first action zone (161, 261) being higher than the second action zone (162, 262).

The unit of claim 1, wherein the first tool (101, 201) is a gripper tool of at least one cell element (2), intended to engage a cell element (2), and in which the second tool (120, 220, 270) is an intervention tool on the electrolytic bath.

3. Unit according to claim 1 or claim 2, wherein the elevation system is shaped so that, in the upper position of the intermediate portions (1 13, 213) and lower (1 15, 215), the first and second tools (101, 201, 120, 220, 270) are in a storage position (163, 263) located higher than the first and second action zones (161, 261, 162, 262).

4. Unit according to any one of the preceding claims, comprising:

an actuator (135, 235) adapted to cause the intermediate portion (1 13, 213) to move relative to the upper portion (1 12, 212), said actuator (135, 235) having a portion attached to the upper portion (1 12, 212) and a portion secured at the lower portion of the intermediate portion (1 13, 213), and / or an actuator (136, 236) adapted to cause the lower portion (1 15, 215) to move by relative to the intermediate portion (1 13, 213), said actuator (136, 236) having a portion fixed in the lower part of the intermediate portion (1 13, 213) and a portion fixed at the bottom of the lower portion (1 15 , 215).

5. Unit according to one of claims 1 to 4, wherein the upper guide axis (1 14) and the lower guide axis (1 16) are substantially merged.

6. Unit according to claim 5, wherein the elevation system comprises a telescopic mast (1 1 1, 1 1 1 a, 1 1 1 b), the lower portion (1 15) being slidably mounted to the inside of the intermediate portion (1 13), and the intermediate portion (1 13) being slidably mounted inside the upper portion (1 12).

The unit of claim 5 or 6, wherein the first tool is a hood gripper (101).

8. Unit according to one of claims 5 to 7, wherein the second tool is a cleaning tool (120) of the cell (2) - such as a shovel.

9. Unit according to claims 7 and 8, wherein, in projection in a horizontal plane (X, Y), the first action zone (161) comprises at least two parts (161 a, 161 b) disjoint, and the second action zone (162) is located between said two parts (161a, 161b) of the first action zone.

The unit of claim 9, including stop means adapted to stop the downward movement of the lower portion (1-15) relative to the intermediate portion (1 13) when the first tool (101) is in progress. intervention, so as to avoid interference between the first and second tools (101, 120), and / or between a tool (101, 120) and a portion of a tank (6) of a cell (2).

1 1. Unit according to one of claims 1 to 4, wherein the upper guide axis (214) and the lower guide axis (216) are distinct and offset from each other.

12. Unit according to claim 1 1, wherein the intermediate portion (213) is slidably mounted inside the upper portion (212), and in that the lower portion (215) is slidably mounted relative to the portion intermediate (213), outside the intermediate portion (213).

13. Unit according to claim 1 1 or 12, wherein the first tool is an anode assembly gripper (201).

14. Unit according to one of claims 1 1 to 13, wherein the second tool is a tool (220) for breaking the crust that forms during electrolysis.

The unit of claim 14, wherein the service module (36) comprises: means for moving the tool to break the crust (220, 270) relative to the carriage (35), substantially vertically downward, for bringing said tool (220, 270) into contact with the crust; means for moving the tool to break the crust (220, 270) in a substantially horizontal translation relative to the carriage (35), for producing a break line (380, 380a) along at least one vertical side of the spent anode (16b);

and guiding means (230) shaped to guide said movement in translation substantially horizontal relative to the carriage (35) of the tool to break the crust (220, 270).

16. Unit according to claim 15, wherein the service module (36) comprises two tools for breaking the crust (220, 270), said tools (220, 270) being arranged vis-à-vis in substantially parallel planes, being spaced from each other by a distance (DY) greater than the dimension (dY) of an anode in the longitudinal direction (X) or the transverse direction (Y), so as to produce two break lines (380, 380a) on either side of the anode (16b).

17. Unit according to any one of claims 14 to 16, wherein the tool (220, 270) for breaking the crust, or at least one of the tools for breaking the crust, comprises a rotatable disc (220) fit to cut the crust, the rotating disc (220) having an axis (221) extending substantially horizontally, being rotated about its axis (221), and being driven in translation in a direction substantially horizontal and orthogonal to said axis ( 221), the service module (36) further comprising means for rotating the rotating disk (220) about its axis (221).

The unit of any one of claims 14 to 16, wherein the crust breaking tool, or at least one of the crust breaking tools, comprises a piercer (270) arranged substantially vertically and means for moving the breaker (270) reciprocally along a substantially vertical direction between a low position where the breaker (270) penetrates at least part of the crust and a high position where the breaker (270) is located above the crust, the means for moving said breaker (270) in a substantially horizontal translation being designed to move the breaker (270) when the latter is in the up position.

19. Aluminum production plant by igneous electrolysis, comprising:

- a building in which several cells (2) are located; each cell (2) extending in a transverse direction (Y), the cells (2) being arranged next to each other in a longitudinal direction (X) by providing at one of their ends an operating aisle (5) longitudinal; each cell (2) may contain a plurality of anode assemblies (15) each including at least one anode (16, 16a, 16b) and an anode rod (17); each cell (2) having an opening (9) closable by a succession of removable covers (10);

a unit (30) according to any one of the preceding claims, the crane (31) being mounted movably longitudinally on longitudinal rails formed in the vicinity of two transverse end walls (3) of the building.

20. Installation according to claim 19, wherein each cell (2) can contain several anode assemblies (15), and in that the opening (9) is an upper opening of the cell (2), located in a plane substantially horizontal, each of the covers (10) being located at the right of an anode assembly (15) contained in the cell (2).

21. A method of operating an installation (1) according to claim 19 or claim 20; characterized in that the method comprises the steps of:

moving the service machine (33) so that the first or the second tool (101, 201, 120, 220, 270) is located in line with a part of a cell (2), hereinafter referred to as the intervention (600);

actuating the lifting means so that the first tool (101, 201) can perform an intervention in a first action zone (161, 261) and / or that the second tool (120, 220, 270) can perform a intervention in a second area of action (162, 262);

said first and second action zones (161, 162, 261, 262) being located at or adjacent to the intervention zone (600), and being further distinct and located at a distance from one another:

and in the vertical direction (Z), the first action zone (161, 261) being higher than the second action zone (162, 262).

22. The method of claim 21, wherein the first and second tools (101, 201, 120, 220, 270) operate in their respective areas of action (161, 162, 261, 262) at different times.

23. The method of claim 21, wherein the first and second tools (101, 201, 120, 220, 270) operate in their respective zones of action (161, 162, 261, 262) at least partly simultaneously.

24. Method according to one of claims 21 to 23, using a service machine (33) whose elevation system comprises:

an intermediate portion (1 13, 213) movable with respect to the upper portion (1 12, 212) along a substantially vertical upper guide axis (1 14, 214), between a high position and a low position, the intermediate portion (1 13, 213) carrying the first tool (101, 201) for performing an intervention in the first action zone (161, 261), in the lower position of the intermediate portion (1 13, 213);

a lower portion (1 15, 215) movable with respect to the intermediate portion (1 13, 213) along a substantially vertical lower guide axis (1 16, 216), between a high position and a low position, the lower portion (1 15, 215) carrying the second tool (120, 220, 270) for performing an intervention in the second action zone (162, 262), in the lower position of the lower portion (1 15, 215) .

25. The method of claim 24, comprising the following successive steps: the intermediate portion (1 13, 213) is displaced relative to the upper portion (1 12, 212), the lower portion (1 15, 215) remaining fixed by relative to the intermediate portion (1 13, 213) and therefore being animated by the same movement as the latter relative to the upper portion (1 12, 212);

then the lower portion (1 15, 215) is displaced relative to the intermediate portion (1 13, 213).

The method of claim 24, wherein moving the intermediate portion (13,133) relative to the upper portion (12,212) and moving the lower portion (1,15,215) relative to the intermediate portion (13, 213) are at least partly simultaneous.

27. Method according to one of claims 21 to 26, wherein the intervention in the first action zone (161) comprises gripping a cover (10) by means of a hood gripper (101), as a first tool, and the intervention in the second action zone (162) comprises cleaning the cell (2) by means of a cleaning tool (120) of the cell, as a second tool.

28. Method according to one of claims 21 to 26, wherein the intervention in the first action zone (261) comprises gripping an anode assembly (15) by means of an anode assembly gripper ( 201), as the first tool, and the intervention in the second action zone (262) comprises breaking the crust that forms during the electrolysis by means of a tool (220, 270) for breaking the crust, as a second tool.

The method of one of claims 21 to 28, wherein the second tool (220, 270) is a crust breaking tool, wherein the elevating means is actuated so that the crust breaking tool. (220, 270) is moved relative to the carriage (35) substantially vertically downward to bring said tool (220, 270) into contact with the crust, and wherein the crust break tool (220, 270) is then moved in a substantially horizontal translation, to achieve a breaking line (380, 380a) along at least one vertical side of the worn anode (16b).

30. The method of claim 29, including the use of two tools for breaking the crust (220, 270) disposed vis-a-vis in substantially parallel planes, said two tools (220, 270) being spaced apart. on the other a distance (DY) greater than the dimension (dY) of an anode in the longitudinal direction (X) or the transverse direction (Y), so as to produce two break lines (380, 380a) on both sides of the anode (16b).

31. Method according to claim 30, characterized in that said two break lines (380, 380a) are parallel to the longitudinal direction (X).

32. Method according to one of claims 29 to 31, wherein the first tool is an anode assembly gripper (201) mounted on the same support (21 1) as the tool for breaking the crust (220, 270). and comprising the step of gripping the anode assembly (15) by means of the anode assembly gripper (201) before placing the tool to break the crust (220, 270) in contact with the crust, so to ensure a good positioning of said tool (220, 270) relative to the anode (16b) to disengage.

33. Method according to one of claims 29 to 31, wherein a rotating disc (220) is used as a tool for breaking the crust, the rotating disc (220) having an axis (221) extending substantially horizontally and being rotated about its axis (221), and that the method further comprises moving the rotating disk (220) in a direction substantially horizontal and orthogonal to said axis (221), so that the line of rupture (380) forms a continuous cut.

34. Method according to one of claims 29 to 31, characterized in that a piercer (270) arranged substantially vertically is used as a tool for breaking the crust, and in that the method further comprises the displacement of the breaker (270) according to a reciprocating along a substantially vertical direction, between a low position where the breaker (270) penetrates at least part of the crust and a high position where the breaker (270) is located above the crust, the displacement of the crust stitching (270) in a substantially horizontal translation being performed when the stitcher (270) is in the upper position.