Installation and method for producing solid oxide stacks

Abstract

The invention relates to an installation (10) intended for the production of solid oxide stacks (14), which comprises: - an enclosure (12) of main axis A in which the stacks (14) are intended to be placed coaxially with the main axis A; - a first shaft (22) and a second shaft (24) between which the stacks (14) are placed; - heating elements (32) arranged in the enclosure (12), characterized in that the main axis A of the enclosure (12) is horizontal and perpendicular to a vertical axis according to the Earth's gravity, and in that the enclosure (12) comprises means for driving the stacks and shafts (22, 24) in rotation about the main axis A.

Description

[0001] Description

[0002] Title: Installation and process for the production of solid oxide stacks

[0003] TECHNICAL FIELD

[0004] The invention relates to an installation for producing solid oxide stacks operating at high temperature. Such stacks are, for example, high-temperature solid oxide electrolysers or high-temperature solid oxide fuel cells.

[0005] The invention more particularly proposes an installation allowing a homogeneous distribution of forces in order to limit the influence of the Earth's gravity in the application of an axial compression force to the stacks. The invention also proposes an installation in which the heat distribution is homogeneous for all the stacks during the production process.

[0006] STATE OF THE PRIOR ART

[0007] A solid oxide electrolyzer or a solid oxide fuel cell, commonly referred to by the acronyms SOEC (Solid Oxide Electrolyzer Cell) or SOFC (Solid Oxide Fuel Cell), consists of an alternating assembly of a plurality of electrochemical units and interconnectors, with one electrochemical unit being interposed between two interconnectors. Each electrochemical unit, also called an electrolysis cell, has two electrodes, namely an anode and a cathode, between which an electrolyte is placed.

[0008] The alternating assembly of electrochemical units and interconnectors forms what will subsequently be called a stack, commonly referred to as a "stack".

[0009] During a production stage of a stack, the assembly of electrochemical units and interconnectors is compressed along its main axis and then installed in a heating enclosure.

[0010] According to a known embodiment, the main axis of the assembly of electrochemical units and interconnectors is oriented vertically and the compression is also carried out vertically, according to the Earth's gravity, that is to say that the elements constituting the stacks are arranged horizontally and are assembled vertically on top of each other.

[0011] The production process for manufacturing a functional stack is achieved by performing a predefined thermal cycle under constant stress and supplying the chamber with a sweep gas to protect the elements constituting the stack against high-temperature oxidation. During this thermal cycle, the sealing of each electrochemical unit and each stage of the stack is formed, the heating transforming the sintered glass slip, which is present on the interconnection plates, into a glass-ceramic. The gas sweep at temperature also allows the reduction of the electrochemical cell mounted at the heart of the interconnection plates.

[0012] This production process combines the application of mechanical stress with a temperature cycle, which results, among other things, in a significant variation in the height of the stack (between 30 and 50% of the initial height). This process must therefore be carried out in a controlled manner to ensure conformity of the geometry of the stack.

[0013] Good vertical guidance of the elements constituting the stack during this operation is necessary. Also, the temperature in the enclosure and the mechanical compression of the elements constituting the stack must be controlled and uniform over the entire duration of the manufacturing process, which can exceed 48 hours, and this, over the entire height of the stack.

[0014] The equipment used today is a vertical shaft furnace which has a lower part with a sole equipped with a rigid support on which the elements constituting one or more stacks are assembled. These furnaces have a ceiling in the upper part with an axial opening allowing the passage of a rod / crossbar which is used to compress the assembly of the elements constituting the stack(s). External mechanical devices such as jacks, springs or gravity loads coupled with a lever arm are used to ensure that a constant force is maintained. The vertical guidance of the elements constituting the stack(s) is ensured by a column-type device located either internally or externally of the stacks.

[0015] Such a manufacturing process has certain drawbacks. In particular, the total height of the assembly comprising the elements constituting the stack(s) is limited due to constraints linked to Earth's gravity.

[0016] In fact, each element constituting the stack(s) is subjected to the continuous compressive force which is exerted on all the elements constituting the stack(s), as well as to the self-weight of all the elements which are located above the element considered.

[0017] Therefore, the elements located vertically at the bottom of the stack are subjected to an axial force which is greater than the force exerted on the elements located at the top of the stack.

[0018] This constraint is even more marked in multi-stack type structures made up of several sub-stacks which integrate several thick and therefore heavier end plates.

[0019] Also, such a vertical orientation of the stack of elements presents a difficulty in ensuring sufficiently precise guidance during the axial collapse phase of the structure linked to the transformation of the glass frit which passes from a solid state to a viscous state before forming a glass-ceramic structure.

[0020] Finally, the vertical orientation of the assembly presents a thermal disadvantage.

[0021] Indeed, in a vertical structure, the convection effects during the heating / cooling phases, to which are added thermal losses in the upper part of the structure, linked to the mechanical support devices (conduction loss in the support rods and the presence of openings in the furnace ceilings), require fine multi-zone regulation to ensure a uniform temperature over the entire height of the assembly. This regulation is all the more complex to implement as the height of the assembly gradually decreases during the process. It is now known that differences of a few tens of degrees have a very strong impact on the viscous behavior and the crystallization kinetics of the seal during its formation.

[0022] The aim of the invention is to propose an installation and a method for producing at least one stack of electrochemical cells making it possible to reduce, or even eliminate, the disadvantages linked to production with a vertical orientation.

[0023] STATEMENT OF THE INVENTION

[0024] The invention proposes an installation intended for the production of solid oxide stacks, which comprises

[0025] - an enclosure with main axis A in which the stacks are intended to be placed coaxially with the main axis A,

[0026] - a first shaft and a second shaft between which the stacks are placed,

[0027] - heating elements arranged in the enclosure, characterized in that the main axis A of the enclosure is horizontal and perpendicular to a vertical axis according to the Earth's gravity, and in that the enclosure comprises means for driving the stacks and the shafts, in rotation around the main axis A.

[0028] Such a horizontal orientation of the main axis A of the enclosure allows for homogeneity of the axial support force exerted on the components of the stack or plurality of stacks. Indeed, the action of Earth's gravity is no longer taken into account for this axial force. In addition, there is no longer a heat gradient according to the vertical height due to the effects of thermal convection, which allows for thermal regulation in the enclosure. In addition, the rotation of the shafts and stacks around their axis during the conditioning treatment of the stacks makes it possible to balance the forces that the stacks undergo from Earth's gravity and to avoid the gravitational flow of the glass when it passes into a viscoplastic state, which allows for a better distribution of the vitroceramic joint formed by the glass around the stacks.This rotary movement also guarantees homogeneous heating of all the components constituting each stack 14, and therefore homogeneous reduction treatment of the electrochemical cells.

[0029] Preferably, the enclosure is cylindrical with a circular section (axis A).

[0030] Preferably, the drive means comprise a motor coupled to the first shaft.

[0031] Preferably, the heating elements consist of a plurality of rectilinear elements parallel to the main axis A, which are distributed around the main axis A and around the stacks when the stacks are installed in the enclosure.

[0032] Preferably, the installation comprises at least one radial support device which centers the stacks during their rotation around the main axis A.

[0033] Preferably, the radial support device comprises a longitudinal bar which is movable in a radial direction relative to the main axis A and comprises means for driving the longitudinal bar in the radial direction.

[0034] Preferably, the installation comprises a plurality of radial support devices which are distributed around the main axis A.

[0035] Preferably, at least one shaft among the first shaft and the second shaft is axially movable in translation along the main axis A relative to the enclosure.

[0036] Preferably, the installation comprises a cradle mounted to rotate inside the enclosure around the main axis A and in which the stacks are placed coaxially with the main axis A.

[0037] Preferably, the cradle comprises an end flange which is connected to a motor for driving the cradle in rotation around the main axis A.

[0038] Preferably, the cradle has a central hub on either side of which the stacks are arranged.

[0039] Preferably, the two shafts are movable in opposite and simultaneous movements along the main axis A. Preferably, the installation comprises a linkage connecting an actuator to the shafts, which transforms a movement of the actuator into opposite and simultaneous movements of the shafts,.

[0040] Preferably, the cradle carries a plurality of longitudinal bars intended to bear against the stacks.

[0041] Preferably, the installation comprises a device for positioning the stacks coaxially with each other in which the stacks are assembled with their main axes B vertical, according to the Earth's gravity.

[0042] Preferably, the installation includes means for clamping the stacks to allow them to be handled before being placed in the enclosure.

[0043] BRIEF DESCRIPTION OF THE DRAWINGS

[0044] [Fig. 1] is a schematic perspective representation of an installation according to the invention.

[0045] [Fig. 2] is a schematic representation in axial section of the installation shown in Figure 1.

[0046] [Fig. 3] is a two-step schematic representation of the installation of the stacks in the guide tooling.

[0047] [Fig. 4] is an illustration of the cooperation of the clamping tool with the stacks.

[0048] [Fig. 5] is a side view in axial section of the installation, in which the stacks are placed in the enclosure before the implementation of the thermal cycle.

[0049] [Fig. 6] is a schematic perspective representation of an installation adapted to stacks of square section according to a second embodiment of the invention.

[0050] [Fig. 7] is a schematic perspective representation of a rotating cradle suitable for implementing the second embodiment of the invention. [Fig. 8] is a side view in axial section of the installation, in which the stacks are placed in the enclosure before implementing the thermal cycle.

[0051] DETAILED DESCRIPTION OF THE INVENTION

[0052] For the description of the invention, the orientations according to the reference V, L, T indicated in the figures corresponding respectively to a vertical direction V, a longitudinal direction L and a transverse direction T will be adopted without limitation.

[0053] Figure 1 shows an installation 10 intended for the production of stacks of several layers forming electrochemical cells.

[0054] PREGNANT

[0055] The installation comprises an enclosure 12 in which a plurality of stacks 14, commonly called "stacks" and which are shown in Figure 3, are produced.

[0056] Each stack 14 is made up of an alternation of a plurality of electrochemical units and interconnectors, as indicated previously. Such stacks 14 form solid oxide electrolyzers or solid oxide fuel cells.

[0057] According to a first aspect of the invention, the installation 10 is suitable for the production of stacks 14 each having a main cylindrical shape of revolution having a main axis B, a cylindrical external wall and two axial end faces 20.

[0058] The enclosure 12 consists of an element of revolution around a main axis A which is oriented horizontally, that is to say perpendicular to the Earth's gravity. Here, the main axis A is oriented in the longitudinal direction L.

[0059] The cylindrical interior volume of the enclosure 12 is thus also cylindrical in shape and with a horizontal main axis A. To allow access to its interior volume, the enclosure 12 is made in two parts, preferably two half-shells 16, one shell 16 of which is fixed to a support frame 18 and the other half-shell 16 is removable from the first half-shell 16. The stacks 14 are assembled to each other according to a method which will be described later, to form an assembly in which the stacks are joined by their axial end faces 20 and in which the main axes of the stacks are coincident. The assembly then forms a cylindrical element having a main axis coincident with the main axis B of each stack 14.

[0060] The assembly thus formed is placed in the enclosure 12 so that its main axis B coincides with the main axis A of the enclosure 12.

[0061] SUPPORT AXES

[0062] The enclosure 12 comprises two shafts 22, 24 for supporting and driving the assembly in rotation around the main axis A of the enclosure. The two shafts 22, 24 are arranged axially on either side of the assembly, relative to the main axis A of the enclosure 12.

[0063] As can be seen in Figure 2, a first shaft 22, located to the right of this Figure 2, is mounted at a first longitudinal end of the enclosure 12. It passes through an axial end wall 26 of the enclosure 12 and it is guided in rotation around the main axis A relative to this axial end wall 26. Thus a section of this first shaft 22 is arranged in the interior volume of the enclosure, a second section of the first shaft 22 is arranged outside the enclosure 12. This second section of the first shaft 22 is connected to a drive motor 28 which is fixed to the chassis 18.

[0064] The second shaft 24 is mounted at the second longitudinal end of the enclosure 12, that is to say here at the left end in Figure 2. This second shaft 24 passes through a second axial end wall 30 of the enclosure 12 and it is mounted so that it can move relative to this second axial outlet end wall 30 that it is free to rotate around the main axis A of the enclosure 12 and so that it is mounted so that it can move in translation along this main axis A of the enclosure 12.

[0065] The installation 10 comprises means (not shown) for driving the second shaft 24 in axial displacement to place the stacks 14 under axial pressure during the implementation of the thermal cycle.

[0066] The second shaft 24 is furthermore a hollow axis, it defines at least one conduit 48 connecting the interior volume of the enclosure 12 with a supply source of sweeping gases used during the thermal cycle. These sweeping gases have a protective function for the elements, such as for example hydrogen which has the function of preventing the oxidation of materials at high temperature.

[0067] Suitable guide members (not shown) are arranged between each shaft 22, 24 and the wall 26, 30 of the enclosure 12 associated with it to provide both guidance for each shaft 22, 24 and insulation of the interior volume of the enclosure from the exterior during the process.

[0068] HEATING ELEMENTS

[0069] The enclosure 12 also comprises heating elements 32 which are distributed along the axial length of the enclosure and which are distributed regularly around the main axis A.

[0070] Preferably, as shown in the figures, each heating element 32 consists of a longitudinal rectilinear element parallel to the main axis A, which is mounted on the cylindrical central part of the enclosure 12. The longitudinal length of each heating element 32 is defined to allow all of the stacks 14 to be heated homogeneously. Thus, preferably, each heating element extends over the entire longitudinal length of the enclosure 12.

[0071] The heating elements 32 are distributed around the stacks 14, when the latter are placed in the enclosure, which allows all of the stacks 14 to be exposed to uniform heat during the heating cycle.

[0072] RADIAL SUPPORT DEVICES

[0073] The enclosure 12 also comprises radial support devices 34 which are designed to center the stacks 14 during the process. Indeed, as the thermal cycle progresses, the dimension of the stacks 14 along the main axis A decreases, while their radial dimension relative to the main axis A increases.

[0074] Furthermore, even if, during the thermal cycle, the stacks are rotated in order to balance the forces they undergo from the Earth's gravity, they may possibly shift relative to each other. Thus, by using the radial support devices 34, the stacks 14 are all maintained in a good coaxial position with the main axis A, which further guarantees optimal heating thereof.

[0075] Here, the enclosure 12 carries three radial support devices 34, it will be understood that it can carry a different number of such devices, for example six.

[0076] Each radial support device 34 comprises a longitudinal bar 36 which is intended to come into contact with the stacks 14.

[0077] The longitudinal bar 36 extends longitudinally, that is to say it is parallel to the main axis A. Its longitudinal length, as well as its longitudinal position in the enclosure 12 are defined so that the longitudinal bar is in contact with all the stacks 14 during the thermal cycle.

[0078] Each radial support device 34 also comprises rods 38 for guiding the longitudinal bar 36 in movement in a radial direction relative to the main axis A.

[0079] Each rod 38 is thus oriented radially relative to the main axis A and passes through the cylindrical wall of the enclosure 12. The wall of the enclosure 12 comprises for this purpose a cylindrical bearing surface 40 which is associated with each rod 38 and which is passed through by the associated rod 38. The cylindrical bearing surface 40 further comprises sealing means (not shown) making it possible to prevent any leakage of gas from the enclosure 12.

[0080] Here, the rods 38 are two in number, they are parallel to each other and are offset longitudinally. They are connected together at their internal radial ends by the longitudinal bar 36 and at their external radial ends, which are located outside the enclosure 12, by a connecting bar 42 of longitudinal main orientation.

[0081] Each radial support device 34 also comprises means for driving the longitudinal bar 36, and therefore the rods 38 and the connecting bar 42, in radial displacement in the direction of the main axis A or away from the main axis A. The driving in radial displacement in the direction of the main axis A is carried out by means of a jack 44 which acts on the connecting bar 42 to bring it closer to the wall of the enclosure 12.

[0082] The drive in radial displacement away from the main axis A is carried out by means of at least one spring 46, here two springs 46, each spring 46 of which is compressed radially between the connecting bar 42 and the wall of the enclosure 12.

[0083] Thus, by controlling the jack 44, it is possible to modify the distance of the longitudinal bar 36 relative to the main axis A, as well as the support force of the longitudinal bar 36 against the stacks 14.

[0084] GUIDE TOOLS

[0085] As previously stated, before being placed in the interior volume of the enclosure 12, the stacks 14 are assembled with each other to form an assembly in which the stacks 14 are joined by their axial end faces 20 and their main axes B are merged.

[0086] For this, as can be seen in Figure 3, the stacks 14 are placed vertically on top of each other with their main axes B coaxial with each other. Also, a guide tool 50 is used to position the stacks 14 coaxially with each other.

[0087] The guide tool 50 comprises a flat and horizontal base 52 and vertical arms 54, preferably three in number, which extend upwards from the base 52 and between which the stacks 14 are received. When installing the stacks in the guide tool 50, the main axes B of the stacks are oriented vertically according to the Earth's gravity and the stacks 14 are kept coaxial with each other by means of the vertical arms 54 between which the stacks 14 are received.

[0088] CLAMPING TOOLS

[0089] When all the stacks 14 are placed on the guide tool 50, they are secured together by a clamping tool 56 shown in FIG. 4, which clamps all of the stacks 14 in the axial direction of the stack.

[0090] The clamping tool 56 here consists of two identical elements 58; it will be understood that the clamping tool 56 may comprise a different number of such elements 58.

[0091] Each element 58 consists of a bar which is substantially parallel to the common main axis B of the stacks 14, that is to say which is substantially vertical when the element is placed on the guide tool 50.

[0092] A first end 60 of the element 58 comprises a protruding lug perpendicular to the rest of the element 58, which is intended to come into contact with an axial end face 20 of a stack 14 located at one end of the set of stacks 14, preferably here against a lower axial end face 20 of the stack 14 located vertically at the bottom of the set, and therefore against a face which bears against the base 52 of the tool 50.

[0093] The second end 62 of the element 58 carries a movable finger 64 which projects relative to the rest of the element and which is intended to come into contact with an axial end face of a stack 14 located at a second end of the set of stacks 14, preferably here against an upper axial end face 20 of the stack 14 located vertically at the top of the set, and therefore against a free end face of the set of stacks 14.

[0094] The position of the movable finger 64 along the element 58 is adjustable, to allow axial clamping of the set of stacks 14 between the movable finger and the lug, with a view to handling this set of stacks 14 outside the guide tool 50, without the stacks 14 moving relative to each other.

[0095] MANUFACTURING PROCESS

[0096] In the following description, the steps which are successively implemented for the manufacturing method using an installation 10 according to the invention will be described.

[0097] Firstly, the stacks 14 are assembled with each other and coaxially with each other by using the guide tool 50. This assembly is carried out by installing the stacks 14 one by one in the guide tool with their main axes B oriented vertically.

[0098] After having installed all of the stacks 14 which are to undergo the thermal cycle in the guide tool 50, these are secured together by the use of the clamping tool 56, that is to say by the use of several elements 58 which clamp the stacks 14 together. The amplitude of the clamping force produced by the elements 58 is sufficiently large to hold the stacks 14 together during their handling, without being too large so as not to damage the stacks 14.

[0099] The subassembly consisting of the assembled stacks 14 and the clamping tool 56 is then placed in the enclosure 12.

[0100] To do this, one of the half-shells 16, preferably the upper half-shell 16, is dismantled beforehand, leaving sufficient space for the installation of the sub-assembly.

[0101] The installation of the sub-assembly in the enclosure 12 consists first of placing the main axis B of the sub-assembly coaxial with the horizontal main axis A of the enclosure 12 then positioning the sub-assembly between the two shafts 22, 24.

[0102] This positioning of the subassembly between the two shafts 22, 24 is carried out by first placing the set of stacks in abutment against the first shaft 22 then by axially translating the second shaft 24 in the direction of the first shaft 22 to come into abutment against the set of stacks 14.

[0103] Then, a first axial stress is exerted via the second shaft 24 on the stacks 14.

[0104] The amplitude of this first axial stress is at least equal to the amplitude of the clamping force applied by the clamping tool 56 on the stacks 14, which thus makes it possible to hold the subassembly in place between the shafts 22, 24.

[0105] Then, the elements 58 of the clamping tool 56 are separated from the stacks 14. The stacks 14 are held in place by the axial support of the second shaft 24 on the stacks 14. The elements 58 are subsequently stored outside the enclosure 12. The enclosure 12 is then hermetically closed by the assembly of the half-shell 16 which had previously been dismantled.

[0106] Finally, the longitudinal bars 36 of the radial support devices 34 are brought into contact with the periphery of the stacks 14.

[0107] According to an alternative embodiment, the longitudinal bars 36 of the radial support devices 34 which are associated with the lower half-shell 16 are positioned radially to support the subassembly and position it coaxially with the main axis A of the enclosure, before contact is made and therefore before axial support is placed on the second shaft 24 against the stack assembly 14.

[0108] Installation 10 before the implementation of the thermal cycle is shown in Figure 5.

[0109] The thermal cycle during which the stacks 14 are heated can then be implemented.

[0110] This thermal cycle consists of putting the stacks 14 into rotation around the main axis A. For this, the motor 28 is powered in a controlled manner to have a constant and determined rotation speed.

[0111] Also, the interior volume of the enclosure 12 is either filled with sweep gases at a controlled flow rate and pressure, these sweep gases are supplied into the enclosure via the conduit 48 formed in the second shaft 48 or an air vacuum is formed in the interior volume of the enclosure 12.

[0112] The support force exerted by the second shaft 24 is controlled and maintained throughout the thermal cycle to accompany the reduction in the axial dimension of the stacks 14. The possibility of moving the second shaft 24 along the main axis A makes it possible to compensate for the reduction in the axial dimension of the stacks 14.

[0113] Finally, the heating elements 32 are activated to uniformly heat the interior volume of the enclosure 12 as well as the stacks 14 during the implementation of the thermal cycle.

[0114] The rotation of all the stacks 14 makes it possible, when the glass passes into a viscoplastic state, to prevent its gravitational flow. This rotary movement also guarantees uniform heating of all the components constituting each stack 14, freeing itself from the convective effects observed in vertical furnaces. The peripheral radial support devices 34 ensure the guidance and correct alignment of the rotating stacks 14 during the manufacturing process.

[0115] At the end of the thermal cycle, the enclosure 12 is opened by dismantling the upper half-shell 16. The elements 58 of the clamping tool 56 are put back in place on the stacks 14 and maintain an axial compression force on the stacks 14 to allow their manipulation without them moving relative to each other, or becoming detached, during the manipulation of the subassembly.

[0116] The possibility of moving the movable finger 64 allows the same element 58 to be mounted on all of the stacks 14, whether before the implementation of the thermal cycle, in which case the dimension of each stack along its main axis B is the largest, or after the implementation of the thermal cycle, in which case the dimension of each stack 14 along its main axis B is reduced.

[0117] The second shaft 24 is then moved back axially, that is to say it is moved away from the first shaft 22, to separate the subassembly from the shafts 22, 24.

[0118] The subassembly comprising the clamping tool 56 and the set of stacks 14 is then removed from the interior volume of the enclosure 12. The clamping tool 56 is then removed, the stacks 14 can then be integrated into a module.

[0119] SECOND EMBODIMENT

[0120] Figures 6 and following show an installation suitable for the manufacture of stacks 14 of cylindrical shape with a square section.

[0121] Unlike the previous embodiment, during rotation of the stacks in the enclosure 12, it is not possible to use a radial support device 34 carried by the enclosure 12, which comes into contact with the cylindrical wall of the stacks 14.

[0122] The installation comprises heating elements 32 similar to those of the first embodiment, that is to say which extend at least over the entire longitudinal length of the stacks 14 when they are placed in the enclosure. ROTARY CRADLE

[0123] According to this second aspect of the invention, the stacks 14 are held in their shape by means of a rotating cradle 70 in which the stacks 14 are positioned for implementing the thermal cycle, and which is mounted to rotate around the main axis A.

[0124] The rotating cradle 70, shown in more detail in Figure 7, is in the main shape of a cylindrical revolution coaxial with the main axis A of the enclosure 12.

[0125] It comprises a cylindrical structure 72 made in two parts 74, one part of which is removable to allow access to the interior volume of the rotating cradle, a central hub 76 and two end flanges 78.

[0126] Each end flange 78 is crossed by a shaft 22, 24. In addition, each of the two shafts 22, 24 is here mounted to slide axially relative to the end flange 78 associated with it to achieve axial clamping of the stacks against the central hub 76.

[0127] The rotating cradle 70 is driven in rotation about the main axis A by an external motor 28 which meshes with a toothed wheel 80 carried by one of the two end flanges 78.

[0128] The rotary cradle 70 further comprises openings 94 formed in the two parts 74 which are designed to allow the elements 58 of the clamping tool 56 to be deposited after having placed the stacks 14 in the rotary cradle 70 and closed the latter.

[0129] LONGITUDINAL BARS

[0130] Also, the longitudinal bars 36 are carried by the rotating cradle 70, so that they follow the stacks during their rotation around the main axis A. They are arranged inside the rotating cradle 70 and they are distributed around the main axis A to define a plurality of support planes against which a lateral face of the stacks 14 is supported.

[0131] Thus, preferably, the longitudinal bars 36 are distributed into several pairs, each pair of longitudinal bars 36 defining a support plane associated with a lateral face of the stacks 14. The longitudinal bars 36 are further distributed over the two parts 74 of the rotary cradle 70.

[0132] Thus, the stacks 14 are first installed on the longitudinal bars of the first part 74 of the rotary cradle 70 then, when the second part 74 of the rotary cradle 70 is assembled with the first part, the longitudinal bars 36 which it carries come to bear against the stacks 14.

[0133] TWO-SHAFT DRIVE

[0134] As previously stated, the two shafts 22, 24 are all movable along the main axis A and clamp the stacks 14 together and against the central hub 76.

[0135] Each shaft 22, 24 has an internal end provided with a support plate 82 which is intended to come into contact with an axial end face 20 of the stacks 14.

[0136] The installation 10 also comprises a device 84 for driving the two shafts 22, 24 in longitudinal translation towards each other to apply the clamping force to the stacks 14.

[0137] The drive device 84 comprises a jack 86 for producing the clamping force and a linkage 88 connecting each end 90 of the jack 86 to an external end 92 of a shaft 22, 24 which is associated with it and which is located outside the enclosure 12. The linkage 88 is connected to each external end 92 of a shaft 22, 24 by a ball joint.

[0138] The linkage 88 makes it possible to distribute the force produced by the jack 86 evenly towards the two shafts 22, 24 so that this clamping force is substantially identical on either side of the central hub 76. The linkage 88 also has the effect of driving the two shafts in opposite and simultaneous movements to each other. That is to say that the linkage allows a simultaneous approach or a simultaneous separation of the two shafts 22, 24.

[0139] MANUFACTURING METHOD In the following description, the steps which are successively implemented for the manufacturing method using an installation 10 according to the second embodiment of the invention will be described.

[0140] Firstly, the stacks 14 are assembled on top of each other and coaxially with each other using a guide tool (not shown).

[0141] This assembly is carried out by installing the stacks 14 one by one in the guide tooling with their main axes B oriented vertically.

[0142] After having installed all of the stacks 14 which are to undergo the thermal cycle in the guide tool 50, these are secured together by the use of the clamping tool 56, that is to say by the use of several elements 58 which clamp the stacks 14 together. Here, since the stacks 14 are of square section, four elements 58 are used, one element 58 being arranged at each face of the stacks.

[0143] The magnitude of the clamping force produced by the elements 58 is sufficiently large to hold the stacks 14 together during handling, without being too large to damage the stacks.

[0144] The subassembly consisting of the assembled stacks 14 and the clamping tool 56 is then placed in the rotating cradle 70 and therefore in the enclosure 12.

[0145] For this, one of the half-shells 16, preferably the upper half-shell 16, is first dismantled from the other half-shell 16, leaving sufficient space for the installation of the sub-assembly. Similarly, the upper part 74 of the rotating cradle 70 is first dismantled.

[0146] The installation of the subassembly in the cradle consists first of positioning it on the longitudinal bars 36 which define a space complementary to the stacks 14.

[0147] The second part 74 of the rotary cradle 70 is put in place and fixed on the first fixed part 74 to close the rotary cradle 70 and to press all the longitudinal bars 36 against the side walls of the stacks 14. Then, the two shafts 22, 24 are pressed axially against the stacks 14 by an axial translation of the shafts 22, 24 towards the stacks 14, and therefore in the direction of the central hub 76. By this axial support of the shafts 22, 24, a first axial stress is exerted on the stacks 14.

[0148] The amplitude of this first axial stress is at least equal to the amplitude of the clamping force applied by the clamping tool 56 on the stacks 14.

[0149] Then, the elements 58 of the clamping tool 56 are separated from the stacks 14 and are removed through the openings 94 formed in the two parts 74 of the rotary cradle 70. The elements 58 are consequently stored outside the enclosure 12.

[0150] The enclosure 12 is then hermetically sealed by assembling the half-shell 16 which had previously been dismantled.

[0151] The thermal cycle can then be implemented.

[0152] This thermal cycle consists of putting the stacks 14 into rotation around the main axis A. For this, the motor 28 is powered in a controlled manner to have a constant and determined rotation speed.

[0153] Also, the interior volume of the enclosure 12 is either filled with sweeping gases at a controlled flow rate and pressure, these sweeping gases are supplied via the conduit 48 of the second shaft 24 or an air vacuum is formed in the interior volume of the enclosure 12.

[0154] The axial support force exerted by the two shafts 22, 24 is controlled and maintained throughout the thermal cycle to accompany the reduction in the axial dimension of the stacks 14. The possibility of moving the two shafts 22, 24 along the main axis A makes it possible to compensate for the reduction in the axial dimension of the stacks 14.

[0155] Finally, during the thermal cycle, the heating elements 32 are activated to uniformly heat the interior volume of the enclosure 12 as well as the stacks 14. The rotation of all the stacks 14 makes it possible, when the glass passes into a viscoplastic state, to prevent its gravitational flow. This rotary movement also guarantees uniform heating of the structure, freeing itself from the convective effects observed in vertical furnaces.

[0156] At the end of the thermal cycle, the enclosure 12 is opened by dismantling the upper half-shell 16. The elements 58 of the clamping tool 56 are replaced on the stacks 14 through the openings 94 of the rotating cradle 70.

[0157] The rotating cradle is then opened by dismantling the upper part 74.

[0158] The two shafts 22, 24 are then moved back axially, that is to say they are moved away from each other and from the central hub 76, making it possible to separate the stacks 14 from the shafts 22, 24.

[0159] The subassembly comprising the clamping tool 56 and the set of stacks 14 is then removed from the interior volume of the enclosure 12. The clamping tool 56 is then removed, the stacks 14 can then be integrated into a module.

[0160] As other embodiment variants, the enclosure and / or the rotating cradle may have a single-piece structure with a design for positioning the stacks 14 by translation along the main axis A.

[0161] In this variant, the rectilinear heating elements can optionally be replaced by solenoid type heating elements.

[0162] NOMENCLATURE:

[0163] 10 installation

[0164] 12 speakers

[0165] 14 stacks

[0166] 16 half-shells

[0167] 18 chassis

[0168] 20 axial end face

[0169] 22 first tree 24 second tree

[0170] 26 axial end wall

[0171] 28 engine

[0172] 30 axial end wall 32 heating elements

[0173] 34 radial support device

[0174] 36 longitudinal bar

[0175] 38 stems

[0176] 40 cylindrical bearing 42 connecting bar

[0177] 44 cylinder

[0178] 46 springs

[0179] 48 conduit of the second shaft

[0180] 50 guide tool 52 base

[0181] 54 vertical arms

[0182] 56 clamping tools

[0183] 58 unique element

[0184] 60 first end 62 second end

[0185] 64 mobile finger

[0186] 70 rotating cradle

[0187] 72 cylindrical structure

[0188] 74 parts 76 central hub

[0189] 78 end flanges

[0190] 80 toothed wheel

[0191] 82 support plate

[0192] 84 drive device 86 cylinder linkage cylinder end outer end openings

Claims

Claims 1. Installation (10) intended for the production of solid oxide stacks (14), which comprises - an enclosure (12) of main axis A in which the stacks (14) are intended to be placed coaxially with the main axis A, - a first shaft (22) and a second shaft (24) between which the stacks (14) are placed, - heating elements (32) arranged in the enclosure (12), characterized in that the main axis A of the enclosure (12) is horizontal and perpendicular to a vertical axis according to the Earth's gravity, and in that the enclosure (12) comprises means for driving the stacks and the shafts (22, 24) in rotation around the main axis A.

2. Installation (10) according to the preceding claim, characterized in that the enclosure is cylindrical with a circular section.

3. Installation (10) according to any one of the preceding claims, characterized in that the drive means comprise a motor (28) coupled to the first shaft (22).

4. Installation (10) according to any one of the preceding claims, characterized in that the heating elements (32) consist of a plurality of rectilinear elements parallel to the main axis A, which are distributed around the main axis A and around the stacks (14) when the stacks are installed in the enclosure (12).

5. Installation (10) according to any one of the preceding claims, in combination with claim 2 characterized in that it comprises at least one radial support device (34) which centers the stacks (14) during their rotation around the main axis A.

6. Installation (10) according to the preceding claim, characterized in that the radial support device (34) comprises a longitudinal bar (36) which is movable in a radial direction relative to the main axis A and comprises means (44, 46) for driving the longitudinal bar (36) in the radial direction.

7. Installation (10) according to claim 5 or 6, characterized in that the installation comprises a plurality of radial support devices (34) which are distributed around the main axis A.

8. Installation (10) according to any one of the preceding claims, characterized in that at least one shaft among the first shaft (22) and the second shaft (24) is movable in translation axially along the main axis A relative to the enclosure (12).

9. Installation (10) according to claim 1, characterized in that it comprises a cradle (70) mounted to rotate inside the enclosure (12) around the main axis A and in which the stacks (14) are placed coaxially with the main axis A.

10. Installation (10) according to the preceding claim, characterized in that the cradle (70) comprises an end flange (78) which is connected to a motor (28) for driving the cradle (70) in rotation around the main axis A.

11. Installation (10) according to claim 9 or 10, characterized in that the cradle (70) comprises a central hub (76) on either side of which the stacks (14) are arranged.

12. Installation (10) according to any one of claims 9 to 11, characterized in that the two shafts (22, 24) are movable in opposite and simultaneous movements along the main axis A.

13. Installation (10) according to the preceding claim, characterized in that it comprises a linkage connecting an actuator (86) to the shafts (22, 24), which transforms a movement of the actuator (86) into opposite and simultaneous movements of the shafts (22, 24).

14. Installation (10) according to any one of claims 9 to 13, characterized in that the cradle (70) carries a plurality of longitudinal bars (36) intended to bear against the stacks (14).

15. Installation (10) according to any one of the preceding claims, characterized in that it comprises a device (50) for positioning the stacks (14) coaxially with each other in which the stacks (14) are assembled with their main axes (B) vertical, according to the Earth's gravity.

16. Installation (10) according to the preceding claim, characterized in that it comprises means for clamping the stacks (14) to allow their handling before their placement in the enclosure (12).