WO2013045771A1

WO2013045771A1 - Compact service module and use thereof in a plant for producing aluminum by electrolysis

Info

Publication number: WO2013045771A1
Application number: PCT/FR2012/000376
Authority: WO
Inventors: Stéphane DAVID
Original assignee: E.C.L.
Priority date: 2011-09-28
Filing date: 2012-09-24
Publication date: 2013-04-04
Also published as: EP2761061B1; AU2012314235A1; RU2014116961A; EP2761061A1; BR112014007309A2; CA2848967C; US20140231268A1; FR2980488A1; FR2980488B1; CN103827356B; DK201470091A; CA2848967A1; RU2601717C2; CN103827356A; AR088008A1; IN2014CN03122A; ZA201401432B

Abstract

The invention relates to a service module (19) for a plant for producing aluminum, including a frame (25) and a rotary portion (33) including a hopper (37) mounted on said frame so as to pivot about a substantially vertical axis, said rotary portion being provided with at least one tool (21, 22) mounted on a telescopic arm, said service module including a first support structure (35) which is intended for supporting the entirety of said rotary portion and which is mounted on said frame so as to pivot about a substantially vertical axis, a stationary member (39) of said telescopic arm being mounted on a second structure (41) for supporting said rotary portion via coupling means (43) attached to a coupling portion of said stationary element, said coupling portion being spaced apart from the ends (45, 47) of said stationary element. The invention also relates to a service machine (5), to a service unit including the above-described service module, and to the use of said service unit.

Description

COMPACT SERVICE MODULE AND ITS USE IN A PLANT OF ALUMINUM PRODUCTION BY ELECTROLYSIS

Field of the Invention The invention relates to the production of aluminum by igneous electrolysis according to the Hall-Héroult process. It relates more particularly to service modules used in aluminum production plants.

State of the art

Aluminum is produced industrially by igneous electrolysis in electrolysis cells according to the well-known Hall-Héroult process. The plants contain a large number of electrolysis cells arranged in line, in buildings called halls or electrolysis rooms, and electrically connected in series using connecting conductors. The cells are generally arranged to form two or more parallel lines that are electrically bonded together by end conductors.

The operation of an electrolysis plant requires interventions on the electrolysis cells including, in particular, the replacement of spent anodes with new anodes, the removal of liquid metal from the cells and the removal or addition of electrolyte. In order to carry out these interventions, the most modern factories are equipped with one or more service units comprising a movable bridge that can be translated over the electrolysis cells, and along the series of cells, and one or more a plurality of service machines each comprising a trolley and a service module provided with handling and intervention devices (often called "tools"), such as shovels and hoists, and able to be moved on the movable bridge. These service units are often referred to as "electrolysis service machines" or "M.S.E" ("PTA" or "Pot Tending Assembly" or "PTM" or "Pot Tending Machine" in English).

In order to optimize the space in the electrolysis rooms and to reduce the cost of the investments, the electrolysis cells are arranged as close as possible to each other and close to one of the lateral sides of the rooms. electrolysis and a traffic lane as narrow as possible is arranged near the other lateral side of the rooms. This provision requires that the distance between the walls of the electrolysis room and the limits of the working area of each of the tools of the service machines is as small as possible, especially for access to the electrolysis cells. This distance is called "tools approach". The position of the cells in the electrolysis room and the total area of the room that results depend substantially on the volume occupied by the service machines and the possibilities of approach and movement of their tools. However, the known service modules occupy a large volume which prohibits a reduced approach to the sides of the electrolysis rooms, including the lateral sides, and which substantially limits their movements near these sides. The volume of the modules can be reduced by a reconciliation of the tools. However, this solution can increase the risk of damage to tools during maintenance operations.

The European patent EP 1 781 839 of the applicant proposes a service module comprising a frame adapted to be fixed to a carriage and a turret mounted on said frame so as to be pivotable about a vertical axis, said turret being equipped with a plurality of handling and intervention devices. This service module comprises a set of tools mounted on telescopic arms, each telescopic arm being fixed to the turret by an articulated support allowing pendular movements of said telescopic arm with respect to a determined point of articulation In this service module, the telescopic arms are interconnected by a mechanical connection device for maintaining, within a given tolerance range, the relative angular difference between the pendular movements of said telescopic arms. Such a service module allows the tools to be brought together thereby limiting the volume, in particular the width, under the chassis of said module. It also gives the tools a limited independence of movement, while avoiding that they collide and that the jolts suffered by one of the tools have a direct impact on the other tools.

A technical problem of the service module of the prior art is to further minimize the volume under the chassis of said module, including the height under the chassis of the service module, and the volume of the space covered by the entire service module when rotating its rotating part.

Description of the invention

An object of the invention relates to a service module for use in an igneous electrolysis aluminum production plant, said module comprising a chassis adapted to be fixed to a carriage and a rotating part mounted on said frame so as to be able to pivot around a substantially vertical axis, said rotary part being equipped with at least one tool mounted on a telescopic arm of said rotary part, said service module further comprising a first supporting structure mounted on said frame and intended to carry a hopper, said service module being characterized in that said first carrier structure and said hopper are included in said rotatable part, said first support structure being adapted to carry all of said rotatable portion and being mounted on said frame so as to pivot about said substantially vertical axis, and in that said rotatable portion comprises a second supporting structure, a fixed member of said telescopic arm being mounted on said second support structure integral with said rotary part by means of hooking means allowing pendular movements of said telescopic arm, said hooking means being fixed to a hooking portion of said fixed member disposed at a distance from the ends said fixed member.

Most often, the service module is mounted on the trolley of a service machine, said trolley being, in turn, mounted on the movable bridge of a service unit that can be translated over the cells of the machine. electrolysis. Thus, the rotating part of the service module is generally arranged or suspended under the carriage, that is to say still under the chassis of said service module. More specifically, this rotating part is generally rotatably mounted on the frame so as to be pivotable, usually on itself, about a substantially vertical axis. In what follows, this rotating part can be indifferently called turret.

The first support structure being designed to carry all of said rotating part and being mounted on said frame so as to pivot about said substantially vertical axis, this first bearing structure therefore generally constitutes the upper part of said rotating part.

The rotating part is generally equipped with a determined set of tools, each tool of said assembly being mounted on a telescopic arm attached to the second supporting structure. The telescopic arms on which the tools are mounted, the second support structure, and the attachment means arranged between the second support structure and the telescopic arms are all included in the rotating part. This set of tools may typically comprise at least one tool selected from a scoop shovel, anode handling tongs and a breaker.

According to one aspect of the invention, the hopper is included in the rotating part or turret. The rotating part therefore includes not only the tools and the telescopic arms on which they are mounted, but also the hopper. This hopper, which supplies the electrolysis cell with powdery products, generally has a large volume, compared with the tools and the telescopic arms on which they are mounted. Including this hopper in the rotating part makes it possible to minimize the volume under the chassis of said module, or more precisely the volume of the space covered by the whole of the service module during the rotation of its rotating part, and especially the radial extent with respect to the substantially vertical axis about which said rotary portion is pivotally mounted.

In what follows, the volume of the space covered by the entire service module during the rotation of its rotating part, and in particular during a complete rotation or 360 ° of said rotating part, can be qualified as space congestion. Thus, and in other words, the fact of including the hopper in the rotating part makes it possible to optimize the space requirement, under the chassis, of the service module, and in particular the radial space requirement with respect to the axis. substantially vertical about which said rotatable portion is pivotally mounted. Indeed, in the opposite case where the hopper is fixed relative to the tools, the latter and their respective telescopic arms should be arranged so that their rotation is not impeded by said hopper, that is to say that the tools and their respective telescopic arms should be arranged in a space having a symmetry of revolution relative to the axis of rotation of the rotating part which apart from that occupied by the hopper. This choice of including the hopper in the rotating part thus makes it possible to arrange this hopper, the tools and the telescopic arms on which they are mounted in a space which is generally smaller, because all these objects rotate, at the same time, around the same axis of rotation.

According to another aspect of the invention, the fixed members of the telescopic arms on which the tools are mounted are fixed to the second bearing structure, the latter being secured to the rotating part of the service module. By fixed member of a telescopic arm, is generally meant the shaft in which slides a movable member carrying the tool, said fixed member being in this case attached to the second carrier structure. This second supporting structure, which is distinct from the first support structure mounted on the frame, is therefore disposed under said frame and more precisely under said first support structure. This second support structure is generally arranged under the hopper. The second support structure may advantageously be constituted by a gangway disposed under the hopper. In what follows, the second carrier structure can be described as a gateway, or even under hopper gateway. This gateway can carry other organs than tools, such as, for example, a hydraulic power unit and electrical cabinets. This configuration in which the tools are mounted on the gateway allows maintenance operators to have access to the tools and various bodies of the service module.

Moreover, the tools being mounted on the second carrier structure, the forces exerted by said tools are transferred to said second bearing structure rather than to the first bearing structure carrying the entire rotating part. The use of the second support structure or hopper bridge to fix the tools thus makes it possible to no longer use the first bearing structure carrying the whole of the rotating part or turret to resume the main forces exerted by said tools. This configuration makes it possible to reduce overall the mass of the first bearing structure carrying the entire turret. This configuration also simplifies the construction of the first bearing structure carrying the entire turret.

According to yet another aspect of the invention, the attachment means allow pendular movements of the telescopic arms on which the tools are mounted. This other aspect of the invention not only makes it possible to confer on the telescopic arms an independence of movement with respect to the movement of the rotating part, but also to prevent the jolts suffered by a tool from having a direct effect on the whole assembly. the rotating part, and in particular on the other tools carried by this rotating part.

According to yet another aspect of the invention, the attachment means are attached to an attachment portion of said fixed member disposed at a distance from the ends of said fixed member. In other words, the fixed member of the telescopic arm is not hooked to the second structure by one of its ends. This aspect of the invention improves the accuracy in the positioning of the tool. This aspect of the invention also makes it possible to raise the upper end of the fixed member to an elevation close to that of the frame. Clutter under the frame is thus reduced without the need to reduce the length of the fixed member.

The various aspects of the invention presented above thus contribute to minimizing, even more significantly, the space requirement under the chassis of the service module.

According to a preferred embodiment of the invention, the fixed member of the telescopic arm is connected to the first support structure by a mechanical connection device for limiting the amplitude of the pendular movements of said telescopic arm. In this way, the range of tolerance of the amplitude of the pendular movements of the telescopic arm (s) is even better controlled. Indeed, this range of tolerance is defined with respect to the rotating part, and more particularly with respect to the first bearing structure of said rotary part. Unlike the module described in European Patent EP 1 781 839, the tolerance range of the amplitude of the pendular movements of the telescopic arm of a tool is not defined with respect to other tools of said rotary part. Thus, the range of tolerance of the amplitude of the pendular movements of a telescopic arm is defined more deterministically than in the prior art because it no longer depends on the pendular movements of the other tools. Thanks to this configuration of the service module, the axial or vertical component of the forces exerted by a tool and the telescopic arm on which it is mounted is taken up by the second support structure or undercarriage, through the means of hanging. The radial or horizontal components of these forces are, in turn, partly taken up by the first bearing structure carrying the entire rotating part or turret under the chassis, via the mechanical connection device.

According to a preferred embodiment of the invention, the attachment portion of the fixed member of the telescopic arm is at a distance D from an upper end of said fixed member greater than one-tenth of the length L of said fixed member. Preferably, the distance D between the attachment portion and the upper end of the fixed member is between a quarter of the length L of said fixed member and two thirds of the same length. For example, the distance D between the attachment portion and the upper end of the fixed member is equal to half the length L of said fixed member. In this way, the accuracy and robustness of the tool are improved.

Preferably, the mechanical connecting device is mounted to connect the upper end of the fixed member to the first support structure. Advantageously, the mechanical connection device comprises at least one damping system for limiting the amplitude of the pendular movements of the telescopic arm in a horizontal direction. Advantageously, the mechanical connection device comprises two damping systems for limiting the amplitude of the pendular movements of the telescopic arm in two substantially perpendicular horizontal directions.

Preferably, the upper end of the fixed member of the telescopic arm has an elevation just lower than that of the frame. Preferably, the portion of the fixed member between its upper end and its attachment portion extends through an opening of the first carrier structure. In this way, the fixed member of the telescopic arm can extend to the frame, which allows to limit the space under the chassis of the service module.

Preferably, the attachment means are designed to prohibit the rotational movements of the telescopic arm about a longitudinal axis of said arm. This gives the tools freedom of positioning without changing their basic orientation.

According to one embodiment, the attachment means of the telescopic arm on the second support structure comprise first fastening means secured to said second support structure bearing on an upper face of said second support structure. This upper face of the second support structure generally extends in a plane substantially perpendicular to a longitudinal axis of the arm telescopic, so that the telescopic arm, the tool mounted at the end of said telescopic arm and a possible load of said tools exert, on said upper face, support forces through the first fastening means.

Preferably, the first attachment means of the hooking means of the telescopic arm on the second support structure comprise an intermediate support intended to be fastened integrally to the second support structure, said attachment means comprising at least one integral support piece said telescopic arm resting on said intermediate support and allowing pendular movements of said telescopic arm. In this way, the attachment means allow to resume the lifting forces exerted on the second support structure by the telescopic arm when lifting the tool and its possible load.

It should be noted that the tools can be actuated by actuating means, generally hydraulic cylinders or cable hoisting means, the function of which is, firstly, to keep the active tool at the desired level and, on the other hand, to lift this tool and the possible loads handled by this tool. Generally, the line of action of these actuating means coincides with the longitudinal axis of the telescopic arm carrying the tool. The forces exerted by these actuating means are generally lifting forces, that is to say efforts in addition to the weight of the tool, the telescopic arm on which it is mounted and the load possibly handled by this tool. The downward forces exerted by the actuating means are generally minimized because of the own weight of the tool and its telescopic arm. In this way, the presence of at least one fulcrum on the upper face of the second support structure is theoretically sufficient to take up the lifting forces exerted by the tools.

Preferably, the at least one support piece (in this case the two support pieces) comprises a fuse element intended to break when the amplitude of the pendular movements of the telescopic arm is outside a predetermined range of tolerance. The material of this fuse element and its shape are chosen to limit the forces having a horizontal component transmitted to the second carrier structure. In other words, the fuse element is designed to be broken before risking damage to the fixed element of the telescopic arm or the second supporting structure.

Preferably, the attachment means of the telescopic arm on the second supporting structure comprise second fastening means secured to the attachment portion of the fixed member of said telescopic arm, said second fixing means comprising two uprights oriented substantially parallel to the longitudinal axis of the telescopic arm.

Preferably, the attachment means comprise two support pieces secured to the telescopic arm resting on the intermediate support and allowing pendular movements of said telescopic arm, the fuse element of each support piece being integrally fixed to respectively each amount of second fastening means.

The invention also relates to a service machine comprising a carriage and a service module as described above.

The invention also relates to a service unit of an igneous electrolysis aluminum production plant comprising a mobile bridge and at least one service machine according to the invention.

The invention also relates to the use of a service unit according to the invention for the interventions on electrolytic cells for the production of aluminum by igneous electrolysis.

Brief description of the figures

Figure 1 illustrates a typical electrolysis room, seen in section, for the production of aluminum and comprising a service unit shown schematically.

Figure 2 is a side view of a service machine according to one embodiment of the invention.

Figure 3 is a perspective view of the same service machine as that shown in Figure 2.

FIG. 4 is a perspective view of the service module of the service machine shown in FIG. 2.

Figure 5 is a sectional view of the connecting means between said arm and the second support structure.

Figure 6 is a partial view of the upper part of the fixed member of a telescopic arm and the mechanical connecting device for connecting said arm to the first carrier structure.

Figure 7 is a sectional view of a portion of the mechanical connecting device for connecting said arm to the first support structure. Detailed description of the invention

Electrolysis plants for the production of aluminum comprise a liquid aluminum production zone that includes one or more electrolysis rooms 1. As illustrated in FIG. 1, each electrolysis room 1 comprises cells electrolysis cells 3 and at least one "service unit" or "service machine" 5. The electrolysis cells 3 are normally arranged in rows or rows, each row or line typically comprising more than one hundred cells. The cells 3 are arranged so as to clear a circulation aisle 7 along the electrolysis room 1. The cells 3 comprise a series of anodes 9 provided with a metal rod 11 intended for fixing and electrical connection. anodes to a metal anode frame (not shown). The service unit 5 is used to perform operations on the cells 3 such as anode changes or the filling of the feed hoppers of the electrolysis cells, for example aluminum fluoride. It can also be used to handle various loads, such as tank elements, pockets of liquid metal or anodes. The invention particularly relates to the service units that can be used to effect the anode changes.

The service unit 5 comprises a movable bridge 13 which can be translated over and along the electrolysis cells 3, and a service machine 15 comprising a mobile carriage 17 able to be moved on the mobile bridge 13 and a service module 19 equipped with several handling and intervention devices 21 such as tools (shovels, keys, stitches, ...). The movable bridge 13 rests and circulates on raceways 23, 24 arranged parallel to each other and to the main axis of the room (and the queue of cells). The mobile bridge 13 can thus be moved along the electrolysis room 1. As is illustrated in FIGS. 2 and 3, the service module 19 comprises a frame 25, typically a platform that can be fixed to the trolley 17 and a rotatable portion or turret 33 mounted on the frame 25 so as to be pivotable about a vertical axis A in use. The turret 33 is generally equipped with a balcony or an unrepresented control cabin comprising controls intended to maneuver the module 19 and the handling and intervention members 21, 22. The tools are normally located in the same position. side of the turret 33, namely the side that is below the turret in use.

The carriage 17 of the service machine 5 is mounted on rolling devices 31, 32 intended for rolling the carriage on a rolling path of the moving bridge 13. The frame 25 of the service module 19 is fixed to the carriage 17. The part rotating or turret 33 of the service module 19 is mounted on the frame 25 so as to be pivotable about itself about the substantially vertical axis A shown in Figures 3 and 4. More specifically, the rotating portion 33 is suspended under the frame 25 of the service module.

As illustrated in Figures 2, 3 and 4, the rotatable portion 33 of the service module 19 includes a first carrier structure 35 adapted to carry the assembly of said rotatable portion. This first support structure 35 is mounted on the frame 25 so as to pivot about the substantially vertical axis A shown in FIGS. 3 and 4. More specifically, the first support structure 35 is suspended under the frame 25 of the service module. Thus, the first support structure 35 constitutes the upper part of the rotary part 33.

The rotary portion 33 of the service module 19 further comprises a hopper 37 for supplying an electrolysis cell with pulverulent products, said hopper being carried by the first support structure 35. As explained above, the fact that including this hopper 37 in the rotatable portion 33 minimizes the volume under the frame 25 of the service module, or more precisely the space requirement of this service module.

The rotating part 33 of the service module 19 is equipped with several handling and intervention devices generally comprising a set of tools mounted on telescopic arms. In the exemplary embodiment illustrated in FIGS. 2, 3 and 4, the set of tools includes a crust scoop 21 and an anode handling pliers 22. This set of tools may also comprise, among other things, a piercer. These tools are intended for anode change operations of electrolysis cells. In these operations, the breaker serves to break the crust of alumina and solidified bath which generally covers the anodes of the cell, the crust scoop 21 serves to clear the location of the anode, after removal of the anode used, by removal of solids therein, and the anode handling gripper 22 serves to grip and handle the anodes by their rod, in particular for the removal of spent anodes from an electrolysis cell and the placement of new anodes in the electrolysis cell. The rotating part 33 of the service module 19 may also comprise other tools, which have not been shown, such as a second anode handling gripper, an alumina feed device or a ground bath device. with a retractable conduit, or a hoist.

The telescopic arm on which each tool is mounted means any device comprising at least one fixed member, typically a shaft or an elongated frame, and a movable member, typically a rod or a barrel, adapted to be displaced relative to the member fixed along a given axis, which is generally parallel to the main axis of the fixed member. The fixed member is attached to the service module, in this case to the rotary portion 33 of the service module 19. The tool is, in turn, fixed to the movable member, generally at one end thereof. In the embodiment illustrated in Figures 2, 3 and 4, each telescopic arm comprises a first shaft 39 of substantially square section and a second substantially square section drum slidable within the first shaft. The main axis of the first and second barrels coincide. The main axis of each telescopic arm is generally intended to be substantially vertical in use and is typically parallel to the axis of the fixed member of the same telescopic arm. In other embodiments not shown, the telescopic arm of each tool may comprise one or more complementary intermediate members located between the fixed member and the movable member and slidable relative thereto.

The fixed member of the telescopic arm of each of these tools 21, 22, that is to say the shaft 39 in which slides a movable member of said telescopic arm, is mounted on a second support structure 41. This second support structure is integral of the rotary portion 33 and distinct from the first support structure 35. This second support structure 41 is disposed under the hopper 37. In this case, the second support structure 41 also makes it possible to carry a gangway disposed under the hopper which can be equipped a hydraulic power station and electrical cabinets. The gateway allows maintenance operators to have access to the tools and various components of the service module.

More precisely, as can be seen in FIGS. 2, 3 and 4, the shank 39 of each telescopic arm is mounted on the second support structure 41 by means of attachment means 43 allowing pendulum movements of said telescopic arm while prohibiting the rotational movements of this same telescopic arm about its longitudinal axis. These pendular movements of the telescopic arms make it possible to prevent the jolts undergone by a tool from having a direct effect on the whole of the rotary part 33, and in particular on the other tools carried by this same rotary part. Unlike the service module of the prior art, the shaft 39 of each telescopic arm is not hooked to the second support structure 41 by one of its ends. The attachment means 43 are in fact attached to a hooking portion of the barrel 39 which is spaced apart from the ends of said barrel, that is to say at a distance from the upper end and the lower end of said barrel. . The upper ends of the barrels 39 of the telescopic arms carrying the anode handling tongs 22 and the bucket bucket 21 are shown in Figure 2 as 45. The ends lower barrels 39 of these same telescopic arms are, in turn, shown in Figures 2, 3 and 4 under the reference 47. The drums 39 of the telescopic arms are not hooked to the second support structure 41 by one their ends, they are in fact arranged through openings 49 of the same second carrier structure. These openings 49 are particularly clearly visible in Figure 4. It should be noted that the opening 49 on the right of Figure 4 corresponds to the location of the telescopic arm of a tool that has been removed. With this configuration, the accuracy in the positioning of the tool is improved. Another advantage of this configuration is to limit the space under the chassis 25 of the service module 19.

As shown in FIG. 5, the attachment means 43 of each telescopic arm on the second carrier structure 41 comprise first attachment means 51 integral with this same second carrier structure 41 resting on an upper face 53 of said second bearing structure 41. supporting structure. These first attachment means 51 allow in particular to carry the telescopic arm and the tool. More specifically, the first attachment means 51 are suspended from the second support structure 41. This allows the telescopic arm to be assembled and dismounted beneath said second support structure 41 by an operator positioned on a bridge of the same second supporting structure. The first fixing means 51 of the attachment means 43 comprise an intermediate support 55 intended to be fastened integrally to the second support structure 41 by means of bolts 57 and nuts 58.

The attachment means 43 comprise two support pieces 61 secured to the shaft 39 of the telescopic arm and resting on the intermediate support 55 by allowing pendular movements of said telescopic arm. Each support piece 61 comprises a fuse element 63 intended to break when the forces exerted by the telescopic arm on the second carrier structure 41, in particular the horizontal component of these forces, is outside a predetermined tolerance range. The hooking means 43 of the telescopic arm on the second support structure 41 comprise second attachment means 65 integral with the hooking part of the shaft 39 of the same telescopic arm. These second fixing means comprise, in this case, two uprights 67 oriented substantially parallel to the longitudinal axis of the telescopic arm.

Each tool 21, 22 is actuated by a hydraulic cylinder 62, visible in Figure 4, whose line of action coincides with the longitudinal axis of the telescopic arm carrying the tool. The forces exerted by the cylinders 62 are generally lifting forces, that is to say efforts in addition to the weight of the tool, the telescopic arm on which it is mounted and the load possibly handled by this tool . Downward efforts exerted by the cylinders 62 are generally minimized because of the own weight of the tool and its telescopic arm. In this way, the presence of at least one fulcrum on the upper face 53 of the second support structure 41 is sufficient to take up the lifting forces exerted by the tools via the support pieces 61.

As can be seen in FIG. 4, the barrel 39 of the telescopic arm of each tool 21, 22 is connected to the first support structure 35 by a mechanical connection device 71 making it possible to further limit the amplitude of the pendular movements of said telescopic arm . The horizontal movement of the telescopic arm and the tool carried by said arm is thus limited and the range of tolerance of the amplitude of the pendular movements of the telescopic arm is even better controlled. Thanks to this configuration of the service module 19, the radial or horizontal components of the forces exerted by each telescopic arm are partly taken up by the first support structure 35, by means of the mechanical connection device 71.

In the example shown in Figures 2, 3 and 4, the mechanical connecting device 71 is mounted to connect the upper end 45 of the barrel 39 of each telescopic arm to the first support structure 35. In particular, the upper end 45 of the barrel 39 of each telescopic arm has an elevation just below that of the frame. For this, the portion of the barrel 39 between its upper end 45 and its attachment portion extends through an opening 73 of the first support structure 35.

As can be seen in FIG. 6, the mechanical connection device 71 between the barrel or fixed member 39 of the telescopic arm of each tool and the first carrying structure 35 comprises two damping systems 75, 76 making it possible to limit the amplitude of the pendular movements. telescopic arm in two horizontal directions perpendicular to each other. Each damping system is intended to resume the movement of the barrel 39 in one or other of the horizontal directions. Each damping system also makes it possible to center, or more exactly a return towards a centering position, of the barrel 39.

As can be seen in FIG. 7, each damping system 75, 76 acting in a given horizontal direction comprises a mobile part 79 integral with the barrel 39 of a telescopic arm, as well as a deformable part 81 cooperating with said movable part 79 and with two walls 83, 84 integral with the first support structure 35, to resume all horizontal movement in the given horizontal direction. The deformable part 81 comprises an axial spring 85 acting at its ends on two movable stops 87, 88 cooperating with the two walls respectively 83, 84 integral with the first bearing structure 35. The movable portion 79 integral with the barrel 39 comprises, as to it, two annular parts 89, 90 for sliding along sleeves formed on the two movable bumpers respectively 87, 88 based on one or the other of said movable bumpers according to the movement of the barrel 39. These parts annular 89 also maintain the two movable bumpers 87, 88 in contact with the ends of the spring 85.

With this damping system 75, 76, any movement of the barrel 39 of a telescopic arm and of the movable part 79 integral with said barrel is accompanied by a deformation of the deformable part 81 by compressing the spring 85 by means of one or other of the annular parts 89, 90 and movable buffer 87, 88 on which slides said annular piece. At the same time, this same movable bumper 87, 88 is detached from the wall 83, 84 secured to the first support structure 35, while the opposite movable bumper 88, 87 relies even more strongly on the other wall 84, 83 integral with this same supporting structure. The moving part 79 and the barrel 39 of the telescopic arm are then returned to their initial position thanks to the spring 85. In this way, the range of tolerance of the amplitude of the pendular movements of the barrel 39 of each telescopic arm is even better controlled.

Claims

A service module (19) for use in an igneous electrolysis aluminum production plant, said module comprising a frame (25) adapted to be attached to a carriage (17) and a rotatable portion (33) mounted on said frame pivotable about a substantially vertical axis (A), said rotary portion being provided with at least one tool (21, 22) mounted on a telescopic arm of said rotatable portion, said service module further comprising a first structure carrier (35) mounted on said frame and for carrying a hopper (37), said service module being characterized in that said first carrier structure (35) and said hopper (37) are included in said rotatable portion (33), said first support structure (35) being adapted to carry all of said rotatable portion (33) and being mounted on said frame (25) so as to pivot about said substantially vertical axis, and in that said portion otative comprises a second supporting structure (41), a fixed member (39) of said telescopic arm being mounted on said second supporting structure (41) integral with said rotary portion (33) by means of attachment means (43) allowing pendular movements of said telescopic arm, said hooking means (43) being fixed to a hooking portion of said fixed member disposed at a distance from the ends (45, 47) of said fixed member.

Service module according to claim 1, characterized in that the fixed member (39) of the telescopic arm is connected to the first support structure (35) by a mechanical connection device (71) for limiting the amplitude of the pendular movements of said telescopic arm.

Service module according to claim 2, characterized in that the attachment portion of the fixed member (39) of the telescopic arm is at a distance (D) from an upper end (45) of said fixed member, greater than one-tenth of the length (L) of said fixed member.

Service module according to one of Claims 2 or 3, characterized in that the mechanical connecting device (71) is mounted for connecting the upper end (45) of the fixed member (39) to the first supporting structure (35). ).

Service module according to any one of claims 2 to 4, characterized in that the mechanical connecting device (71) comprises at least one damping system (75, 76) for limiting the amplitude of the pendular movements of the telescopic arm according to a horizontal direction.

Service module according to claim 5, characterized in that the mechanical connecting device (71) comprises two damping systems (75, 76) making it possible to limit the amplitude of the pendular movements of the telescopic arm in two substantially perpendicular horizontal directions.

7. Service module according to any one of claims 1 to 6, characterized in that the upper end (45) of the fixed member of the telescopic arm has an elevation just lower than that of the frame (25).

8. Service module according to any one of claims 1 to 7, characterized in that the portion of the fixed member between its upper end (45) and its attachment portion extends through an opening (73) of the first supporting structure (35).

9. Service module according to any one of claims 1 to 8, characterized in that the attachment means (43) are designed to prohibit the rotational movement of the telescopic arm about a longitudinal axis of said arm.

10. Service module according to any one of claims 1 to 9, characterized in that the rotating part (33) is equipped with a set of tools (21, 22), each tool of said assembly being mounted on a telescopic arm attached to the second support structure (41).

11. Service module according to claim 10, characterized in that the set of tools comprises at least one tool selected from a crust shovel (21), anode handling tongs (22) and a breaker.

12. Service module according to any one of claims 1 to 11, characterized in that the attachment means (43) of the telescopic arm on the second support structure (41) comprise first fastening means (51) integral with said second carrier structure (41) bears on an upper face (53) of said second carrier structure. 13. Service module according to claim 12, characterized in that the first fastening means (51) of the hooking means (43) of the telescopic arm on the second carrier structure (41) comprise an intermediate support (55) for to be fastened integrally to the second support structure, said attachment means comprising at least one support piece (61) integral with said telescopic arm resting on said intermediate support and allowing pendular movements of said telescopic arm.

14. Service module according to claim 13, characterized in that the at least one support piece (61) comprises a fuse element (63) intended to break when the amplitude of the pendular movements of the telescopic arm is out of a predetermined area of tolerance.

15. Service module according to any one of claims 12 to 14, characterized in that the attachment means (43) of the telescopic arm on the second support structure (41) comprise second fastening means (65) integral with the attachment part of the fixed member (39) of said telescopic arm, said second fixing means comprising two uprights (67) oriented substantially parallel to the longitudinal axis of the telescopic arm.

16. Service module according to claims 15, characterized in that the attachment means (43) comprise two support pieces (61) integral with the telescopic arm resting on the intermediate support (55) and allowing pendulum movements. said telescopic arm, and in that the fuse element (63) of each support piece (61) is fixed integrally to each upright (67) of the second fastening means (65).

17. Service machine (5) comprising a carriage (17) and a service module (19) according to any one of claims 1 to 16.

18. A service unit of an igneous electrolysis aluminum production plant comprising a movable bridge (13) and at least one service machine (5) according to claim 17.

19. Use of a service unit according to claim 18 for interventions on electrolytic cells for the production of aluminum by igneous electrolysis.