The present invention relates to a carriage for operating a furnace in an anode baking facility for aluminum electrolysis. The invention also relates to a machine comprising an overhead traveling crane and such a mobile carriage on the overhead traveling crane, and an anode baking facility for the electrolysis of aluminum, comprising a building containing a furnace and such a machine.
The anodes used for the production of aluminum metal according to the Ha!l-Heroult process (i.e., by electrolysis of alumina dissolved in an electrolytic bath) are obtained by molding a carbonaceous paste and by baking at a temperature of about 1200°C. Baking is performed in furnaces usually comprising several adjacent chambers, themselves divided into cells by heating partitions within which flow air and combustion gases supplied by burners.
Many operations necessary for obtaining baked anodes are performed by different tools mounted on a movable carriage above the cells, the carriage having a control station from which an operator can control and manipulate these tools.
The anodes to be baked - "raw" anodes - are stacked in the cells by means of a gripper mounted on the carriage, and completely embedded in a granular or powdery material called coai dust. Coal dust is used to protect the anodes during baking, particularly from the oxidation that they may undergo due to the high baking temperature.
When not in the cells, the coal dust is contained in a tank with a filling duct. The tank is mounted on the carriage so that it can be moved above the furnace to bring the filling duct above each cell to be filled.
During a baking cycle, the burners are progressively moved in relation to the chambers, so that each anode load in a given chamber is successively preheated, subjected to baking, and then cooled. This type of oven is called a "ring furnace". Once the anodes have cooled, they are moved out of the cells by the gripper mounted on the carriage. The coal dust content in these cells is then sucked by a suction pipe mounted on the carriage and then reintroduced into the tank for subsequent filling of another cell.
The anode production rate in the baking facilities needs to be very high. This is because electrolysis plants, generally located near the baking facilities, include a great many electrolytic cells (for example several hundred). And in every electrolytic cell, several anodes or even dozens of anodes are arranged, and these are gradually consumed by electrolysis, in about twenty days on average.
ft follows that the furnaces and the various devices needed for anode baking operations

run constantly. In particular, some of the tools mounted on the carriage, such as the anode gripper or the system for filling the cells with coal dust, particularly the filling duct, and the various associated devices, are constantly in use.
Consequently, these tools have a significant risk of wear and malfunctioning. The carriage 5 and these tools therefore require considerable maintenance which may lead to temporary shutdowns of the anode baking facility, which is obviously not desirable.
It is known that at least some of the tools mounted on the carriage can be duplicated, both to increase the production rate - making it possible to conduct the same operation simultaneously on two separate cells - and, in case of failure of one of the tools, to prevent ) having to shut down the facility, the second tool being able to perform the same function as the failed too!.
However, existing carriages like these on which certain tools are duplicated have a number of drawbacks.
For example, the two tools of the same type may not each be able to access all the cells ; of the furnace. Very often, one of the end cells can be reached by only one of the two tools, it follows that the carriage does not fully meet the objective of redundancy of tools of the same type to counter any failure, nor with the objective of increasing the production rate.
Furthermore, on known carriages, the introduction of a larger number of tools involves an increase in the overall size and weight of the carriage. This has an impact on the dimensions and the structure of the overhead traveling crane on which the carriage can move, as well as on the overall dimensions of the facility. This is not desirable because of the problems of cost and space available.
In addition, known carriages that have a larger number of tools usually have a relatively dense arrangement that may affect accessibility to the different devices carried by the carriage, particularly during maintenance, and also operator visibility of the oven and the cells on which he is working.
The present invention aims to overcome the drawbacks mentioned above.
To this end, and according to a first aspect, the invention relates to a carriage for operating a furnace in a facility for baking anodes for aluminum electrolysis, the furnace comprising a plurality of cells each extending substantially in a longitudinal direction (X) and arranged next to each other in a transverse direction (Y), the center-to-center distance between cells - defined as the transverse distance between the longitudinal median planes of two adjacent cells - being substantially constant, the carnage being

designed to move in the transverse direction above the celi and having a central longitudinai plane.
In the field of the present invention, i.e. the operation of a furnace in an anode baking facility, anode is taken to mean the anode block obtained by molding a carbonaceous, paste, before or after baking. In another field such as the operation of an aluminum electrolysis plant, the term anode may be used instead of anode assembly, i.e. an assembly encompassing not only one or more anode blocks, but also an anode rod supporting the anode block(s) and intended to be fixed onto an anode frame of the electrolysis plant, which is not the case in the field of the present invention.
To simplify description, the term anode will be systematically used in the following instead of anode block.
According to another aspect of the invention, the carriage includes a set of tools each designed to be inserted into a cell. Preferably, the set of tools of the carriage comprises at least one anode gripper, or more accurately at least one anode block gripper.
In the field of the present invention, i.e. the operation of a furnace in an anode baking facility, the anode gripper generally comprises in its lower part two legs that can clamp an anode block or a packet of adjacent anode blocks between them.
According to this invention, the carriage includes a set of tools including at least a first and a second tool of a same first type, each arranged to be inserted into a cell to fulfill a same first function, and each having a substantially vertical axis, the vertical axes of said first and second tools of the first type being spaced, in the transverse direction, by a distance substantially equal to the center-to-center distance between ceits. In addition, the vertical axes of said first and second tools of the first type are arranged substantially symmetrically to the median longitudinal plane of the carriage, the vertical axes of said tools defining between them a substantially longitudinal central corridor on the carnage.
Generally, the first and second tools of the same first type are fixedly arranged on the carriage. Preferably, each tool of the set of tools of the carriage is fixedly arranged on the carriage.
So because of the substantially central and symmetrical arrangement of duplicated tools on the carnage, the transverse distance between the first tool and the first longitudinal sdge of the carriage adjacent the first tool, is substantially identical to the distance between the second tool and the second longitudinal edge of the carriage opposite the first longitudinal edge. This arrangement prevents there being too much of a transversa! offset between one of the tools and an end cell of the building - in the transverse direction - that would prevent this tool from accessing this cell, unless the transverse dimension

between the relevant ceil and the wall of the building of the facility were increased.
The invention therefore makes it possible, while keeping the size of the facility building unchanged, to ensure access of each of these two tools of the same type to each of the cells, thereby providing the desired tool redundancy and productivity gain.
In practice, the central corridor has the shape of a parallelepiped having vertical and longitudinal lateral faces, parallel to the median longitudinal plane of the carriage and passing through the vertical axes of said tools. The axis of a tool is defined as the axis of the working portion of the tool, i.e. the part of the too! which is designed to enter the cell.
The carriage has a substantially longitudinal central area that includes the central corridor and which is arranged substantially symmetrically to the median longitudinal plane of the carriage, the transverse dimension of the centra! area being equal to N times the transverse dimension of the central corridor, N being between 1.4 and 2, preferably between 1.4 and 1.7, for example of the order of 1.5. In practice, this central area has the shape of a parallelepiped having vertical and longitudinal lateral faces, parallel to the median longitudinal plane of the carriage and located on either side of the lateral faces of the central corridor.
Advantageously, the carriage may have a number of additional tools of other types, each arranged to be inserted into a cell to perform other functions, and each having a substantially vertical axis, each of these additional tools of other types being arranged on the carriage so that its vertical axis is located in the central area, and preferably in the central corridor.
This includes the arrangement in which the tools have their axis lying in the plane of a lateral face of the central area, or of the central corridor. Preferably, the tools mounted on the carriage and intended to enter a cell are arranged integrally in the central area or in the central corridor.
This centered arrangement of the tools, for example of all the tools of the carriage designed to enter a cell, enables a rational compact arrangement to be created on the carriage. This also reduces the lengths of the components connecting the various tools and accessories, which contributes to optimizing the arrangement and improving access to the tools, improved operator visibility can also be achieved.
In one possible embodiment, the additional tools comprise at least a first and a second tool of a same second type, different from the first type, each arranged to be inserted into a cell to perform a same second function, different from the first function, the vertical axes of said first and second tools of the second type being spaced, in the transverse direction by a distance substantially equal to the center-to-center distance between the cells, said

first and second tools of the second type further being arranged substantially symmetrically relative to the median longitudinal plane of the carriage.
In other words, the vertical axes of the tools of the second type and the vertical axes of the tools of the first type are aligned longitudinally in pairs, and the vertical axes of the second type tools are included in the plane of a lateral face of the central corridor.
Concretely, the tools mounted on the carriage and intended to be inserted into a cell may belong to the group comprising: an anode gripper, a duct for filling the ceils with coal dust, a pipe for sucking the coal dust contained in a cell.
In one possible embodiment, the carriage comprises at least two grippers and / or at least two filling ducts.
For example, the carriage comprises a single suction pipe for the coal dust contained in a cell, said suction pipe having a substantially vertical axis which is located substantially in the same longitudinal vertical plane as the vertical axis of one of the tools of the first type. In other words, the vertical axis of the coal dust suction pipe is in the plane of a lateral face of the central corridor.
The carriage may further comprise a lifting device having a hook, said hook being arranged in the central area, and preferably in the central corridor.
The carriage may further include a coal dust storage hopper having a substantially vertical axis, this axis being situated in the central area, and preferably in the central corridor. Due to its very high capacity, the hopper does not necessarily have to be contained in its entirety in the central region or the central corridor. According to the invention, however, the largest part of the hopper is preferably contained in the central region or the central corridor.
In one possible embodiment, the carriage further comprises a control station arranged on the carriage so as to be substantially centered with respect to the median longitudinal plane of the carriage, the control station being preferably arranged substantially in the centra! area. This also contributes to the compactness and rationality of the arrangement of the carriage, while improving visibility for the operator. In particular, it ensures that the operator has a view of the bottom of the cell when using a tool in this ceil.
For example, the control station may be arranged in the longitudinal direction between one or more duct(s) for filling the cells with coal dust and one or more anode grippers.
Advantageously, the control station may include a seat which can rotate about a substantially vertical axis, and the seat can be rotated to face a transverse vertical plane in the direction of one of the tools, at least when performing the operation corresponding

to the function of said tool.
In particular, the operator occupying the seat can look towards the duct(s) for filling the cells with coal dust, during the filling operation, contrary to prior art where, during this operation, the seat being arranged to face a longitudinal vertical plane, in the direction of this duct, the operator had to lift the duct and move forward to see the bottom of the cell.
In one possible embodiment, the carriage further comprises devices designed to enable the operation of said tools but not to be inserted into a ceil, these devices being arranged on the carriage outside the central corridor, and preferably outside the central area, indeed, insofar as these devices are not intended to intervene directly in the cells, provision is made according to the invention to place them outside the central area or central corridor to prevent them from unnecessarily cluttering this part of the carriage.
Preferably, said devices may be arranged on the carriage on the same side of the central corridor, or the central area. With this arrangement, it is possible to have, on the other side of the central corridor, or the central area, an access corridor with as few elements as possible, which notably facilitates maintenance.
Said devices belong, for example, to the group comprising: a pump, a cooling device, a suction hopper, a filter.
The area in which these devices are arranged may also contain the ducts connecting these devices together. This arrangement solves the difficulty involved in fitting this cumbersome suction system.
It may be decided that some devices - such as an electrical compartment - should not be located outside the central corridor, or the central area because of carriage and operating positioning requirements. In this case, preferably, the device concerned can be arranged at one longitudinal end of the carriage, to restrict its impingement on the central corridor, or on the central area.
With the invention it is therefore possible to provide a carriage whose transverse dimension is smaller than in prior art. This transverse dimension may be less than 8500 mm, preferably less than 8400 mm, and more preferably less than 8300 mm. In addition, due to the optimization of the arrangement, despite the decrease in the lateral dimension, the longitudinal dimension of the carriage may remain unchanged. It may be of the order of 13600 mm, for example.
According to a second aspect, the invention relates to a machine for operating a furnace in a facility for baking anodes for aluminum electrolysis, the furnace comprising a plurality of chambers extending in a transverse direction and arranged one beside the other in a

longitudinal direction, each chamber having a plurality of cells each extending substantially in the longitudinal direction and arranged next to each other in the transverse direction. The machine includes:
an overhead traveling crane comprising two beams extending transversely the crane being designed to move in the longitudinal direction above the cells;
a carriage as described above, the carriage being mounted to be mobile transversely on the two beams of the overhead traveling crane.
In one possible embodiment, the longitudinal distance between the two beams of the crane is defined by:
D=E+F+G+H+I+J+K+L+M
where, in the longitudinal direction:
F is half the dimension of an anode gripper mounted on the carriage;
H is the dimension of a control station mounted on the carriage;
J is the dimension of a duct mounted on the carriage for filling the ceils with coal dust;
L is the dimension of a suction pipe mounted on the carriage for sucking the coal dust contained in a cell;
E, G, I, K, M are respectively functional clearances between a beam and the adjacent gripper, the gripper and the control station, the control station and the filling duct, the filling duct and the suction pipe, the suction pipe and the adjacent beam.
According to a third aspect, the invention relates to a facility for baking anodes for aluminum electrolysis, comprising:
a building in which is located an anode baking furnace, the furnace comprising a plurality of chambers extending in a transverse direction and arranged one beside the other in a longitudinal direction, each chamber having a plurality of cells each extending substantially in the longitudinal direction and arranged next to each other in the transverse direction.
a machine as described above, the overhead traveling crane being mounted so as to be longitudinally mobile on longitudinal rails provided in the vicinity of two transverse end walls of the building.
In one possible embodiment, the transverse dimension of the carriage is defined by: Ly = 2A - B + 2C,
where, in the transverse direction:

A is the cell approach distance, i.e. the distance between a longitudinal rail and the longitudinal median plane of the end celi adjacent to said rail;
B is the distance between the vertical axes of said first and second tools of the first type, substantialiy equal to the center-to-center distance (d) of the ceils;
C is the authorized overrun, i.e. the distance between a longitudinal rail and the corresponding transverse end wall of the building.
We now describe, as a non-limiting example, a possible embodiment of the invention, with reference to the appended figures:
Figure 1 is a perspective view of a baking facility for anodes for aluminum electrolysis according to the invention, the facility comprising a furnace comprising a plurality of cells;
Figure 2 is a view similar to figure 1 additionally showing a machine according to the invention for operating the furnace, the machine comprising an overhead traveling crane and a carriage;
Figure 3 is a perspective view of the carriage and of the tools and devices that it may include;
Figure 4 is a schematic top view of the carriage;
Figure 5 is a perspective view of the carriage;
Figure 6 is a side view of the carriage;
Figure 7 shows, seen in the longitudinal direction, the overhead traveling crane with the carriage in its two end lateral positions:
Figures 8 and 9 are partial representations of the facility, with the carriage in one of its end lateral positions;
Figures 10 to 12 illustrate the machine and the operator's visibility, when gripping a pack of anodes, when filling a cell with coal dust, and during suction of coal dust respectively.
Figure 1 shows a facility 1 for baking anodes for aluminum electrolysis. The facility 1 comprises a building 2 in which an anode baking furnace 3 is located.
Furnace 3 - known as a ring furnace - includes several chambers 4 extending in a transverse direction Y and arranged next to each other in a longitudinal direction X. Two adjacent chambers 4 - in direction X - are separated by a transverse wall 5. In addition, the chambers 4 are limited at their transverse ends by longitudinal walls 6.
The Z axis is defined as the vertical ascending line, the X, Y, Z axes forming a direct orthogonal reference.

Each chamber 4 comprises a succession of heating partitions 7 longitudinally oriented within which air and combustion gases supplied by burners (not shown) circulate. The burners are mounted above furnace 3 on a mobile system that is moved gradually in relation to chambers 4 during the baking cycle.
Between two heating partitions 7 a cell 8 is defined. In this way each chamber 4 comprises a plurality of cells 8, each extending substantially in the longitudinal direction X and arranged one beside the other in the transverse direction Y. The center-to-center distance d of cells 8 - defined as the transverse distance between the longitudinal median planes of two adjacent cells, as shown in figure 8 - is substantially constant. The arrangement of cells 8 in the transverse direction is therefore substantially regular. For example, d may be of the order of about 1,5 m.
As illustrated in figure 1, the facility 1 comprises an anode conveyor 9 which is here arranged centrally in the building 2, and which extends substantially longitudinally between two rows of chambers 4. This conveyor 9 receives raw anodes 10 made of carbonaceous material, to be baked in the furnace 3.
The facility 1 further comprises a machine 15 for operating furnace 3, as shown in figure 2,
The machine 15 comprises an overhead traveling crane 16 comprising two beams 17 which extend transversely and which are spaced apart - along the X axis - by a longitudinal distance D. The overhead traveling crane 16 is designed to move in the longitudinal direction X above cells 8. To this end, the beams 17 of overhead traveling crane 16 are mounted so as to be longitudinally mobile on longitudinal rails 11,12 each formed in the vicinity of one of the two transverse end walls 13, 14 of building 2.
The machine 15 further comprises a carriage 20 which is mounted so as to be transversely mobile on the two beams 17 of overhead traveling crane 16. The carriage 20 is therefore designed to move in the transverse direction Y above cells 8.
As illustrated in figure 3, the carriage 20 includes a frame 21 having a substantially horizontal platform 22 on which an operator can move, and which is here substantially rectangular. The frame 21 forms the support for the systems for operating furnace 3, namely:
tools to be inserted into the cells 8;
devices that are not intended to be inserted into the cells 8, but that are used for the operation of the machine 15;
a control station 40 from which the operator can control the various tools and devices,

this station being located under the platform 22;
together with a set of ducts, walkways, ladders, etc.
The tools which are mounted on the carriage 20 and which are intended to be inserted into a cell 8 include:
a gripper 23 for gripping anodes 10. A gripper 23 has a substantially vertical axis 24. In its lower part it has two legs 25, each located substantially in a plane (Y, Z) that can clamp between them a packet 26 of anodes 10 comprising several adjacent anodes 10 along the longitudinal direction X (see figure 2). A packet 26 may for example contain between five and nine anodes 10. The gripper 23 can be used to place raw anodes 10 in a cell 8 and remove baked anodes 10 from a cell 8. The gripper 23 can be a single gripper 23a. It can also be a double gripper 23b, which comprises two adjacent single grippers, offset in the transverse direction Y, by a distance B substantially equal to the center-to-center distance d of cells 8, so that the double gripper 23b can work simultaneously in two adjacent cells 8. The gripper 23 may also be a single gripper 23a or a double gripper 23b provided with an auxiliary tool 27;
a duct 30 for filling cells 8 with coal dust. A filling duct 30 has a substantially vertical axis 31. It may be a single filling duct 30a or a double filling duct 30b, which contains two adjacent, single, filling ducts, offset in the transverse direction Y, by a distance B substantially equal to the center-to-center distance d of cells 8, so that the double filling duct 30b can work simultaneously in two adjacent cells 8;
a pipe 33 for sucking the coal dust contained in a cell 8. A suction pipe 33 has a substantially vertical axis 34.
Among the devices that are not intended to be inserted into cells 8, there are a suction pump 35, a cooling device 36, a suction hopper 37 and a filter 38, for example of the cyclone type.
The carriage 20 further comprises a lifting device 41 comprising a hook 42, for example a high capacity hoist, in particular for handling the heating partitions 7 and a hopper 43 for storing coal dust, having a substantially vertical axis 44. The carriage 20 also includes an electrical compartment 45 or electrical cabinet.
The carriage 20 has a median longitudinal plane P, which extends parallel to the X and 2 axes, as shown in figures 3 to 5, in particular. The carriage 20 has a longitudinal dimension Lx and a transverse dimension Ly which, if platform 22 is rectangular, can typically correspond to the length and width of platform 22 respectively.

According to the invention, in order to optimize the arrangement of the carriage 20, it, is planned to place some of the tools to be inserted into cells 8, and preferably all the tools to be inserted into cells 8, centered relative to the median longitudinal plane P. In addition, the tools or devices that are not intended to be inserted into cell 8 do not have to be centered and can therefore be located at another place on the carriage 20, so as not to unnecessarily clutter the vicinity of the median longitudinal plane P.
More specifically, a central corridor 50 is defined on the carriage 20; this corridor has the shape of a parallelepiped having lateral 46, 47 vertical and longitudinal faces, parallel to the median longitudinal plane P, which is centered on plane P, and has a transverse dimension substantially equal to the center-to-center distance d of the cells 8.
In addition, a substantially longitudinal central area 51 is defined on the carriage 20 that includes the central corridor 50 and which is arranged substantially symmetrically to the median longitudinal plane P of the carriage 20. The transverse dimension of the central area is equal to N times the transverse dimension of the central corridor 50, where N is between 1.4 and 2, preferably between 1.4 and 1.7, for example of the order of 1.5. In this way, the central area 51 has the shape of a parallelepiped having lateral 48, 49, vertical and longitudinal faces, parallel to the median longitudinal plane P, and located on either side of lateral faces 46, 47 of the central corridor 50.
^cording to the invention, some of the tools, and preferably all of the tools to be inserted nto cells 8 have their vertical axis included in the central area 51, and preferably in the central corridor 50. in a particularly advantageous embodiment, some of the tools, and preferably all of the tools, to be inserted into cells 8 are included in the central area 51.
n the embodiment shown, the carnage 20 includes a first and a second gripper 23, i.e. a Jouble gripper, and a first and a second duct 30 for filling with coal dust, i.e. a double iliing pipe.
rhe vertical axes 24 of the grippers 23 are arranged substantially symmetrically to the nedian longitudinal plane P of the carnage 20. In other words, since the vertical axes 24 ire spaced along the transverse direction Y, by a distance B substantially equal to the ;enter-to-center d distance of cells 8 and since the central corridor 50 has a width d, the ertical axes 24 of grippers 23 are each included in a lateral face 46, 47 of the central orridor 50.
Similarly, the vertical axes 31 of the coal dust filling ducts 30 are substantially
ymmetrically arranged with respect to the median longitudinal plane P of the carriage 20.
i other words, since the vertical axes 31 are spaced along the transverse direction Y, by
distance B substantially equal to the center-to-center d distance of cells 8 and since the

central corridor 44 has a width d, the vertical axes 31 of the coal dust filler ducts 30 are each included in a lateral face 46, 47 of the central corridor 50.
The axes 24, 31 of grippers 23 and coal dust filling ducts 30 respectively, are located two by two in the same plane (X, 2).
In the embodiment shown, the carriage 20 includes a single suction pipe 33 for the coal dust contained in a cell 8. Advantageously, the vertical axis 34 of the suction pipe 33 is located in the central area 51, and preferably in the central corridor 50. Preferably, the suction pipe 33 is located in its entirety in the central area 51. As seen in figure 4, the vertical axis 34 of the suction pipe 33 can be located substantially in the same plane (X, Z) as a vertical axis 24 of a gripper - or a vertical axis 31 of a filling duct 30.
Moreover, the hook 42 of lifting device 41 can also be arranged in the central area 51, and preferably in the central corridor 50. In the embodiment shown, the lifting device 41 is arranged at one longitudina! end of carriage 20. Moreover, provision may be to have the electrical compartment 45 or the electrical cabinet at the other longitudinal end of carriage 20, possibly substantially transversely centered.
The coal dust storage hopper 43 is also advantageously arranged in a substantially centered way. More precisely, the vertical axis 44 of the hopper 43 may be located in the central area 51, and preferably in the central corridor 50, for example in a lateral face 46, 47 of the central corridor 50.
Advantageously, provision may be made for a substantially centered control station 40 in relation to the median longitudinal plane P of the carriage 20. The control station 40 is preferably arranged substantially in the central area 51. ft comprises a seat 52 for the operator, which can be pivoted about a substantially vertical axis, in this way seat 52 can be turned to face a transverse vertical plane in the direction of the grippers 23, at least during gripping operations of raw or baked anodes 10.
To optimize the arrangement of the carriage 20 and to free up as much of the central area 51 and the central corridor 50 as possible, the devices carried by the carriage 20 which are not intended to be inserted into a cell 8 are preferably placed on the carriage 20 outside the central corridor 50, and preferably outside the central area 51. Preferably, these devices may be arranged on the carriage 20 on the same side of the central corridor 50, or the central area 51. So in the embodiment shown, the suction pump 35, the cooling device 36, the suction hopper 37 and the filter 38 are placed on the carriage 20 on the same side of the central corridor 50,
In the central area 51 or the central corridor 50, and in the longitudinal direction X, the various tools or components of the carriage 20 may be arranged in the following order: the

grippers 23, the control station 40, the coal dust filling ducts 30, and the coal dust suction pipe 33. As the control station 40 is located between the grippers 23 and the filling ducts 30 and is equipped with a swivel seat, it gives the operator excellent visibility over operations performed in cells 8 when gripping anodes 10 and when filling cells 8 with coal 5 dust, which are tricky operations that have to be carried out with precision.
Different provisions could be made, including coai dust filling ducts 30 arranged in the longitudinal direction X, between grippers 23 and hopper 43.
Because of the improved arrangement of the carriage 20, the invention makes it possible to reduce at least one of the dimensions of carriage 20.
) In the embodiment shown, as illustrated diagrammatically in figures 4 and 7, the transverse dimension of the carriage is defined by:
Ly = 2A - B + 2C, where, in the transverse direction Y:
A is the cell approach distance, i.e. the distance between a longitudinal rail 11,12 and the longitudinal median plane of the end cell adjacent to said rail (see also figure 8);
; - B is the distance between the vertical axes of duplicated tools of the same type, i.e. in this case between the axes 24 of the grippers 23 or between the axes 31 of the filling ducts 30, B being substantially equal to the center-to-center distance of cells 8;
C is the authorized overrun, i.e. the distance between a longitudinal rail 11, 12 and the corresponding transverse end wall 13, 14 of the building 2.
■ In practice, we can have:
Ly = 2 x 4300 - 1325 + 2 x 500 - 8275 mm,
whereas known carriages can have a transverse dimension of the order of 8550 mm.
Furthermore, by optimizing the arrangement, the longitudinal dimension Lx of carriage 20 may be unchanged, and for example of the order of 13 600 mm.
In the longitudinal direction X, one also seeks to reduce the distance D between the two beams 17 of the overhead traveling crane 16 to save both space and mass of the facility 1. As shown in figures 4 and 6, the iongstudinai distance D between the two beams 17 of the overhead traveling crane 16 is defined by:
D=E+F+G+H+I+J+K+L+M where, in the longitudinal direction:
F is half the dimension of an anode 10 gripper 23; H is the dimension of the control station 40;

J is the dimension of a duct 30 for filling cells 8 with coal dust;
L is the dimension of the pipe 33 for sucking the coal dust contained in a ceil 8;
E, G, I, K, M are respectively functional clearances between a beam 17 and the adjacent gripper 23, the gripper 23 and the control station 40, the control station 40 and the filling duct 30, the filling duct 30 and the suction pipe 33, the suction pipe 33 and the adjacent beam 17.
In practice, we can have:
D = 600 + 2500 + 500 + 1800 + 500 + 250 + 1000 + 250 + 600 = 8000 mm.
As illustrated in figures 8 and 9, a first advantage of the arrangement of the carriage 20 according to the invention lies in optimizing the operation of the furnace 3 without any negative impact on the dimensions of the facility 1.
Specifically, figures 8 and 9 show the carriage 20 in an end position near a transverse end wall 13 of the building 2,
With unchanged dimensions of building 2, but optimization of the arrangement of carriage 20 according to the invention, and in particular a centered arrangement of the tools, each of the duplicated tools can have access to all the cells 8 of the furnace 3, as illustrated in figure 8.
Alternatively and/or additionally, it may be possible, because of the reduced lateral dimensions of the carriage 20, to reduce the dimensions of the building 2. Figure 9 shows the carriage 20 in an end position close to an end wall 13 of a building 2 according to the invention. In the same figure are also shown, schematically and in dotted lines: a carnage 20' of prior art, having a larger transverse dimension than the carriage 20 according to the invention, and the end wall 13' of building 2' of prior art receiving carriage 20'. By way of example, as illustrated in figure 9, it is possible to reduce the transverse dimension of building 2 by a value Dy of the order of 700 mm.
A second advantage of the invention is, by rationalizing the arrangement of the different tools and devices on the carnage 20, to ensure that the operator in the control station 40 has better visibility during the various operations he performs.
Figures 10 to 12 illustrate the operator's possible field of vision 60 in the direction of cell 8 in which he is working, during the following operations:
gripping a packet 26 of anodes 10 using a gripper 23 or one of the grippers 23, the
anodes 10 being raw or baked (figure 10);
filling a cell 8 with coal dust, using the filling duct(s) 30 (figure 11);

sucking coal dust from a cell 8, once the anodes 10 have been baked, through the suction pipe 33 (figure 12).
Figures 11 and 12 clearly show that, thanks to the invention, the operator has visibility right to the bottom of the relevant cell 8, without having to leave his seat, and in particular 5 without having to stand.
The invention therefore brings a decisive improvement to prior art, by providing a carriage which carries some duplicate tools for reasons of redundancy and production rate, which ensures access for each of these tools to the set of cells in the furnace, and without impairing operator visibility of the cells or increasing the size of the carriage. With the i optimized arrangement of the various tools and devices on the carriage, the invention additionally makes it possible to greatly improve the arrangement of the carriage without requiring the use of many additional ducts linking these tools and devices, which would complicate and weigh down the carriage structure and require more maintenance.
It goes without saying that the invention is not limited to the embodiment described above > by way of example, but includes all technical equivalents and variants of the means described and combinations of these.