MANUFACTURING OF SINGLE OR MULTIPLE PANELS

Abstract

A method of manufacturing of a structured cooling panel includes cutting of desized 2D ceramic into tissues; slurry infiltration in the tissues by at least one knife blade coating method; laminating the tissues in a multi-layer panel, with slurry impregnation after each layer, wherein the tissue has combined fibres and/or pre-build cooling holes; drying; de-moulding; sintering the multi-layer panel, wherein part of the combined fibres burns out during the sintering process leaving a negative architecture forming the cooling structure and/or the pre-build cooling holes define the cooling structure; finishing, using of i) post-machine, and/or ii) surface smoothening/rework, and/or iii) coating application, and/or other procedures.

Claims

1. Method of manufacturing of a structured cooling panel for applying on a component to adapt the final component to a specific cooling function, which is manufactured by the following operations: a) Cutting of desized 2D ceramic into tissues in the right size and shape for the application; b) Slurry infiltration in the tissues by at least one knife blade coating method; c) Laminating the tissues in a multi-layer panel, with slurry impregnation after each layer, wherein the tissue has combined fibres and/or pre-build cooling holes; d) Drying; e) De-moulding; g) Sintering the multi-layer panel, wherein part of the combined fibres burns out during the sintering process leaving a negative architecture forming the cooling structure and/or the pre-build cooling holes define the cooling structure; h) Finishing, using of i) post-machine, and/or ii) surface smoothening/rework, and/or iii) coating application, and/or other procedures.

2. The method according to claim 1, including a pin application with a plurality of pins in order to generate straight cooling paths referring to cooling air holes, through a part of the thickness or through the full thickness of the panel structure comprising at least one of the following steps: namely pins can be: i) metallic pins with a ceramic layer on top to avoid attachment of matrix to the pin and too strong oxidation of the pin during sintering; ii) permanent ceramic pins, that can be easily removed after sintering; iii) pin that will be eliminated during the sintering process via a heat treatment.

3. The method according to claim 2, wherein the eliminated pins are made of a carbon material.

4. The method according to claim 1, wherein the pins are applied by sliding them through a part of thickness or through the panel structure, wherein in order to facilitate the positioning of the pins, a mould underneath can be provided with positioning hole in which the pins are fit into with the appropriated position and angle.

5. The method according to claim 1, wherein the pins are inserted in-between the tissue fibre bundles in order to avoid any damages of the ceramic fibres during the processing and later removal of the pins.

6. The method of claim 1, comprising: combining a supplemental panel structure made of CMC to the multiple panel structure.

7. The method according to claim 6, wherein the combining of the supplemental panel structure comprises one or more of following manufacturing steps: i) the structure is manufactured separately using the same manufacturing route as the standard CMC tissues and an appropriated mould including the drying and de-moulding steps; ii) the structure is slipped in the internal cavity of the multiple panel structure obtained from operations a) to g); iii) both structures are glued using the same ceramic slurry used for the infiltration of the ceramic tissues, or only punctually bound in order to allow a larger lateral movement/expansion of the supplemental structure; iv) the binding between both structures is made by a different joining method, such as a ceramic glue or a brazing technique using metallised surfaces on both ceramic structures.

8. The method according to claim 7, wherein a subsequent drying operation is made, when step iii) is carried out.

9. The method according to claim 7, wherein the supplemental panel structure is an undulated or quasi-undulated configuration.

10. The method according to claim 1, wherein laminating comprises: laminating one to n-layers of ceramic felt, with a slurry infiltration in the felt.

11. The method of claim 10, wherein infiltration of the felt comprises: only outer surface infiltration of the felt in order to bind it to the CMC multiplies panels, or fully impregnation by knife blade coating, after each single layer.

12. Method according to claim 1, comprising: forming the panel structure form as at least one of the constructive elements of a guide vane or rotor blade or liner of a turbomachine, wherein the elements for the purpose of a thermal protection include at least an airfoil, having of at least one CMC shell, at least one intermediate layer, at least one flexible joint with respect to airfoil platform and/or metallic foot, at least one inner platform and outer platform.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0105] The present invention is going now to be explained more closely by means of different embodiments and with reference to the attached drawings.

[0106] FIG. 1 shows various examples of panel arrangements, combination of standard CMC woven tissues with other panel types such as isolation panels (see also FIG. 2) or cooling structure/features panels (see also FIGS. 3a3b);

[0107] FIG. 2 shows a typical panel arrangement where an isolation panel is placed in-between two standard CMC panels. Additionally, the optional application of a ceramic coating on the external surface of the panel arrangement is also shown, here in the pictorial connection with FIG. 1; for detailed description see FIG. 8;

[0108] FIGS. 3a and 3b FIG. 3a show an example of a woven ceramic tissue combining different ceramic fibre bundles forming a specific cooling architecture; FIG. 3b show an example of a ceramic tissue with predesigned/integrated cooling holes features. These tissues are to be used for the formation of cooling structure/feature panels that will be brought in different arrangements with other panel systems as shown in FIG. 1;

[0109] FIGS. 4a-4d show some examples of panel combinations where, for example in FIG. 4d, 3 different panel systems (standard CMC panel, isolation panel and cooling structure/feature panel) are combined;

[0110] FIGS. 5a-5d show same examples of panel combinations as FIG. 4a-FIG. 4d where the next step of insertion of pins to enable the formation of cooling air holes w/o damaging the ceramic fibres of the different tissues has been carried out;

[0111] FIGS. 6a-6d same examples of panel combinations as FIG. 4a-4d in which the pins are removed leaving cooling holes and channels through the multiple layer system;

[0112] FIG. 7 shows a practical example of CMC panel with inserted pins;

[0113] FIG. 8 shows a structure of a typical panel arrangement where an isolation panel is placed in-between two standard CMC panels according to FIG. 2; additionally, the optional application of a ceramic coating on the external surface of the panel arrangement is also shown

[0114] FIG. 9a-9e show various examples of combined fibres architectures, wherein the used fibres are distinctively shown, according to sub-figures FIG. 9a)-FIG. 9e);

[0115] FIG. 10A shows a structure of a compounded panel with cooling channels in-between CMC skins;

[0116] FIG. 10B shows a magnification of FIG. 10A, namely a structure of a compounded panel with cooling channels in-between CMC skins;

[0117] FIGS. 11a and 11b shows a panel structure using tissues with pre-build cooling holes, according to sub-FIGS. 11a and 11b;

[0118] FIGS. 12a-12c show an undulated structure of a panel made of CMC, according to sub-figures FIG. 12a)-FIG. 12c); Sub-figure FIG. 12b) shows the undulated structure attached to a standard CMC panel

[0119] FIGS. 13a-13b show a flexible manufacturing concept with reinforcement inserts referring to a blade/vane airfoil, according to sub-figures FIG. 13a) and FIG. 13b);

[0120] FIG. 14 shows a concept of woven tissues to form a pre-joined Trailing Edge area in order to avoid the CMC at the TE area to rely only on gluing/brazing as joining technology;

[0121] FIGS. 15-17 show part assemblies including different intermediate layer designs;

[0122] FIGS. 18-23 show various example of a metallic airfoil solid fixation, namely:

[0123] FIG. 18 shows an exemplary guide vane of a gas turbine;

[0124] FIG. 19 shows a cross section through the guide vane comprising an additional flow-applied outer hot gas path liner, also called shell module;

[0125] FIG. 20 shows an assembled guide vane in the region of the outer platform, wherein the assembly is made by a brazing and/or frictional connection and/or a mechanical loaded;

[0126] FIG. 21 shows an assembled guide vane in the region of the outer platform, wherein the assembly is made by a ceramic bush;

[0127] FIG. 22 shows an assembled guide vane in the region of the inner platform, wherein the assembly is made by a ceramic bush;

[0128] FIG. 23 shows a guide vane concept.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

[0129] Figures of this description show various embodiment of single and/or multi-plies CMC panels provided for system arrangements. Fundamentally, the CMC panel can be designed with individualized fibre structure in accordance with the operational requirements. A certain percentage of the fibres may have differentiated diameters, which are intended to mainly carry the mechanical load (in the case of the larger diameters) and thermal stresses during the flow-applied operation.

[0130] FIGS. 4a-4d show various examples of panel combinations. Generally, panel means multi-plies of arranged or woven fibres tissues. FIG. 4a) shows a standard CMC panel, also called panel 1, using standard arranged and/or woven fibres tissues. Different layers in a multi-layered panel do not have necessarily the same fibre orientation or weaving architecture. The panel combination according to FIG. 4b), is putting together a standard CMC panel (made of one of multiple plies of a standard ceramic tissues) and a cooling pattern CMC panel (see also description under FIGS. 3a and 3b) also called panel 2.

[0131] FIG. 4c): a cooling pattern CMC panel placed in-between two standard CMC panels.

[0132] FIG. 4d): same as FIG. 4c), but with the addition of an isolation panel (so-called panel 3) at the bottom (in red). Further configurations of the various panels are shown in FIG. 1. These are not the aim of exhaustive configurations.

[0133] Other combinations can be realised depending on the specific application. The layer-up order of the panels can also be different. The panels can be made of complex 3D geometries such as a gas turbine rotor blade/vane airfoil (see the examples under FIG. 1).

[0134] FIG. 2 shows the structure of an isolation panel. For detailed description see FIG. 8.

[0135] The mentioned CMC zones 20, 40 can consist of a laminate structure, such that an appropriate bond between the single intermediate layers (different tissue plies) is achieved. Furthermore, the zones can be formed by a multiple sandwich structure. Laminate structure means the technique of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance or other properties from the use of differing materials. A laminate structure is usually permanently assembled by heat, pressure, welding, or adhesives

[0136] Moreover, the mentioned ceramic felt 30 between the CMC zones 20, 40, likewise build-up of 2D/3D tissue structure with thinner fibres, serves to fix the ceramic matrix to the overall fibre substructure. The fibres of the ceramic felt can be differently woven using the same or different materials, within the ceramic felt and on each side of the panels comprises both first and second fibre materials. Any stacking-sequence of different woven fibres within the thickness of the panel arrangement is also possible.

[0137] FIGS. 3a and 3b various arrangements of cooling architecture panels consisting of at least two embodiments: FIG. 3a) shows a panel using combined fibres architectures for example a standard CMC woven tissue 50 in combination with carbon fibres 60. The other FIG. 3b) shows a panel using tissues with pre-built cooling holes 70. A combination using fibres and tissues with pre-built cooling holes can be made.

[0138] FIGS. 5a-5d show a concept with pins 100, which are inserted through the various panels according to FIGS. 1 to 4 during the manufacturing process of a single panel or of panel combinations. The pins are positioned once the panel structure is built and are removed after the sintering step of the process. Number, size and puncture locations of the introduced pins are determined from case to case, particularly in connection with the cooling requirements of the single panel.

[0139] FIGS. 6a-6d show the mentioned panel arrangements by virtue of FIGS. 5a-5d, in which the pins are removed, thus the resulting channels constitute appropriate cooling holes.

[0140] Additionally, the cooling holes being actively connected to the structured cooling or chaotic running channels within the panel body are designated for convective and/or impingement and/or effusion cooling effects. Furthermore, in some specific configurations or using a specific type of pins, the introduced pins (see FIG. 5b, item 100) through the woven structure can be integrally or partially eliminated by using a thermal and/o chemical treatment.

[0141] One additional point to mention is the fact that the pins can be inserted through the full thickness of a single panel or of a panel combination. However, it can also be the case that the pins are inserted only partially through the thickness of the panel combination, not passing through the whole thickness.

[0142] FIG. 7 shows an example of manufacturing with metallic pins 110 and inserted in the CMC tissue 120 and fixed on the underneath mould before the drying operation. Such an implementation can be made in every above identified panels 1, 2 and 3 (see FIGS. 5a-5c).

[0143] FIG. 8 shows in an enlarged scale the same arrangement as already shown under FIG. 2 and it is equivalent to the panel 3 under FIG. 4c). Of course, all other illustrated panels under FIGS. 4a-4d or FIGS. 5a-5d can also be made.

[0144] FIG. 8 shows the structure of an isolation panel comprises, as viewed from top to bottom, of a coating zone 10, a CMC zone 20 consisting of one or more plies, a centrally (intermediate) arranged ceramic felt 30, which is or not impregnated with ceramic slurry matrix system, and finally a further CMC zone 40 (see also FIG. 8). Depending on the needs, a coating (zone 10) can be added by various different processes, for example thermal spraying, dipping, CVD, etc., on top of the internal or external surface of the panel.

[0145] FIGS. 9a)-9e) show various tissue architectures using combined fibres architectures. The first ceramic fibres 50 (white) are used in the standard CMC woven tissue.

[0146] Complementary fibres 60 (black) consist of carbon fibres. The black fibres are sacrificial fibres that will burn out during the sintering process leaving a negative architecture forming the cooling structure. Both fibres can be differently woven using the same or different materials. The resulting architecture having a rectangular or quasirectangular weaving, or an oblique or quasi-oblique, or non-rectangular angulation weaving. Furthermore, the architecture can be designated as a sinusoidal or quasisinusoidal interdigitated weaving. Any stacking-sequence of different woven fibres within the thickness of the panel arrangement is also possible. FIG. 9a)-9e) reflects the different weaving structure.

[0147] A practical result of a manufacturing according to FIG. 9 is shown in FIGS. 10 A and B. In particular, FIGS. 10A and 10B show the centrally in-between disposed cooling channel structure 130, 140.

[0148] FIG. 11a) corresponds to FIG. 3b) and FIG. 11b) This is an example pf pre-built CAH in a ceramic tissue which is then integrated in the standard CMC panel forming an airfoil with precisely positioned CAHs.

[0149] In this context using a special fabric (see definition under summery of the invention) where the cooling structure (CAHs) is directly woven in within a ceramic fabric and applying as a layer. The performing are as follows: [0150] 1) Cut a stripe or pre-defined geometry tissue from a special fabric. [0151] 2) Integrated stripe or pre-defined geometry tissue into ceramic fabric, e.g., by cutting out the corresponding geometry from the ceramic fabric.

[0152] Referring to FIG. 11b) one layer with a special woven forming the cooling structure (CAHs) provided as a layer.

[0153] FIGS. 12a-12c shows an undulated structure 80, 90 of a main panel or intermediate layer, which is made of CMC. The undulated structure can play the role of bumper and CTE mismatch compensator. The final aim is to combine an undulated structure made of CMC to a single or multiple panel structure obtained from various operations. The undulated structure 80, 90 is manufactured separately using the same manufacturing route as the standard CMC tissues and an appropriated mould including the drying and de-moulding steps. The structure is slipped in the internal cavity of the multiple panel structure obtained from various operations. Both structures can be glued using the same ceramic slurry used for the infiltration of the ceramic tissues, or only punctually bound in order to allow a larger lateral movement/expansion of the undulated structure. The binding between both structures, namely panel/undulated structure, can also be made by a different joining method, such as a ceramic glue or a brazing technique using metallised surfaces on both ceramic structures

[0154] The additional use of a heat and oxidation resistant flexible layer (FIGS. 12a-12c will compensate the CTE mismatch between the ceramic (CMC and metallic IGT core section, such as between the central metallic core and the surrounding shell of rotating or stationary blading (rotor blade/guide vane). It would also comprise a shock absorbing function in case of foreign object impact and avoid a complete disintegration of damaged CMC shell or liner system. Such 3D intermediate layer structure can be made of 3D-structured metallic grid or in form of a corrugated metallic structure, exhibiting a honeycomb or any similar texture.

[0155] FIGS. 12a-13b show a flexible manufacturing concept with reinforcement inserts referring to a blade/vane airfoil, according to sub-FIGS. 13a and 13b, and FIG. 14 shows a concept of CMC woven to join the Trailing Edge (TE) area. See the detailed description on pages 13-15 of this disclosure.

[0156] Two ceramic tissues interwoven at one extremity in order to enable a connection at, e.g., the TE, which is not only relying on gluing/brazing methods.

[0157] FIG. 15 shows a design example using a simple spar or double metallic spar configurations.

[0158] FIG. 16 shows a ceramic reinforcement insert with integrated cooling features.

[0159] FIG. 17 shows an intermediate layer for CTE mismatch control between spar and CMC shell and CMC shell support and cooling control.

[0160] FIGS. 18-23 show various example of a metallic airfoil solid fixation, namely:

[0161] FIG. 18 shows a typically guide vane, which generally has an airfoil 100, an outer platform 200 and an inner platform 300. The outer platform is arranged as a wall element for fixing the guide vane to the inner housing, also called stator, of the gas turbine and forms the outer boundary of a hot-gas duct for the working medium flowing through the turbine. For efficient routing of the flow of the working medium a guide vane row is arranged upstream of a rotor blade row, wherein the guide vanes usually are equipped with a profiled vane airfoil. The guide vane airfoil 100 extends between the vane root, on one side, and a cover plate formed integrally on the vane with respect to the other side; this cover plate or platform delimits the hot-gas duct for the working medium in the direction toward the turbine shaft in the region of the respective guide vane row. The guide vane airfoil and the guide vane root form with the cover plate a vane base body of the corresponding guide vane, which is usually, including optionally the inner platform 300, of single-piece design. A vane base body of this type can be produced, for example, by casting, forging, or if appropriate also in single-crystal form. At least one part of the vane base body, in addition to the airfoil may be manufactured on the basic by an isolation panel according to one or more of the attached claims referring to the present description.

[0162] Accordingly, each guide vane provides a radial outer platform 200, an airfoil 100 and a radial inner platform 300. The radial outer platform contains mounting hooks 201, 202 that are inserted into mounting grooves of the stator component of the first turbine stage (not shown). The inner platform 300 of the guide vane, typically, encloses a gap with the rotor liner through which a purge flow of cooling medium can be injected into the hot gas flow within the gas turbine. In the same way, a purge flow of cooling medium is injected through a gap, which is enclosed by parts of the stator component, the upstream edge of the outer platform 200 of the guide vane and the outer combustor liner, also called stator liner. Generally, downstream of the outer platform 200a heat shield (not shown) is mounted inside of the stator component which prevents overheating of the inner faced areas of the stator component in the same way as in case of the outer platform 200.

[0163] Generally, the means for the purpose of an interchangeable connection of the guide vane elements, namely between airfoil, inner platform, outer platform and optionally flow carrier comprising reciprocal lugs or recesses based on a friction-locked bonding or permanent connection or fixing.

[0164] FIG. 19 shows a cross sectional view through the guide vane, comprising an additional flow-applied outer hot gas path liner 400, also called shell module, as shown in FIGS. 13a and 13b. A guide vane leading edge side cooling passage 100a, intermediate cooling passages 100b, 100c and guide vane trailing edge side cooling passages 100d, 100e are formed, independently, between the guide vane leading edge 400a side and the guide vane trailing edge 400b side.

[0165] The flow-applied shell module encases integrally or partially the outer contour of the based guide vane airfoil of the guide vane according to aerodynamic requirements. The partial shell structure is actively connected to the leading edge of the based airfoil of the guide vane, wherein the outer contour of the based airfoil consists of an independent flow-charged part, being actively connected to the leading edge of the airfoil of the guide vane. The flow-charged shell structure encases integrally the outer contour of the based guide vane airfoil, complying with aerodynamic final aims of the vane, or the flow-charged shell structure encases partially the outer contour of the based airfoil in the flow direction of the working medium of the gas turbine, complying with aerodynamic final aims of the guide vane. According to an additional embodiment the based guide vane airfoil comprises inside a supplementary body formed by the configuration of a spar. In place of the based guide vane airfoil can be made a spar as substructure. The shell structure may be formed by the form of an integrally or segmented body. The first shell structure comprises internally a second or intermediate non-flow-charged or partially flow-charged shell structure, complying with aerodynamic final aims of the vane. The two shell liners are adjacent or have an intermediate distance from one another. When the first flow-charged shell structure encases integrally the outer contour of the guide vane airfoil, this shell structure comprises at least two bodies forming completely or partially the outer contour of the based guide vane airfoil. The mentioned bodies, forming completely or partially the outer shell structure, are brazed or welded along their radial interface, and they have radial or quasi-radial gaps, which are filled with a seal and/or ceramic material. The outer shell is inter-changeable, consumable, pre-fabricated, single or multi-piece with radial or circumferential patches or uses with respect to the sub-structure of the guide vane airfoil a shrinking joint.

[0166] Furthermore, the intermediate shell or shells are parts of an optional assembly. The mentioned shell(s) are inter-changeable, pre-fabricated, arranged as single or multi multi-piece with radial or circumferential patches, uncooled or cooled (convective, film, effusion, impingement cooling), fabricated as compensator for different thermal expansion of outer shell and spar, and with a cooling shirt with respect to different cooling configurations for optimization operational requirements. The spar as sub-structure of the guide vane airfoil or of the shell assembly is interchangeable, pre-fab heated or various manufactured, single or multi-piece, uncooled or cooled using convective, film, effusion, impingement cooling, having a web structure for cooling or stiffness improvement.

[0167] FIG. 20 shows an assembled guide vane in the region of the outer platform, wherein the assembly between airfoil 100 and outer platform 200 resp. airfoil carrier 220 is made by a brazing and/or frictional connection 210. This joint may be mechanically loaded, no absolutely tightness is required. Additionally, the assembled guide vane comprises the following means: The outer platform 200 has an airfoil carrier 220, forming the outer hot gas liner, may be casted, machined or forged. The airfoil carrier may comprise internal local web structure for cooling or stiffness improvement. Material selection and properties are optimized to the individual application. The airfoil carrier 220 comprises flexible cooling configurations provided to functional requirements of the gas turbine with respect to base-load, peak-mode or partial load. Another joint 222 affects the amalgamation between the airfoil 100 and the outer platform 200 on the different levels in radial direction of the guide vane, beyond the above-mentioned assembly between airfoil 100 and outer platform 200, made by a brazing and/or frictional connection and/or mechanical loaded 210. The joint 222 is not constructed to absorb mechanical load, but as a sealing connection. A further joint 225 affects the amalgamation between the outer platform 200 and airfoil carrier 220 on the side of the stator. This joint 225 is not constructed to absorb mechanical load, but as a sealing connection. With respect to the hot gases, the flow-applied underside of the outer platform 200 comprises protective liners 221, 223 on the different levels in radial direction of the guide vane. The mentioned liners 221, 223 are made by a brazing and/or frictional connection and/or mechanical loaded 224. The same measures are applied with respect to the inner platform 300 (not specifically shown).

[0168] Normally, the platforms 200, 300 and the guide vane airfoil are no consumable parts. In contrast, the mentioned sealing and liners are consumable parts. The airfoil carrier may be consumable, depending on costs. The airfoil carrier 220 is cast, machined or forged comprising additionally additive features with internal local web structure for cooling or stiffness improvements. Furthermore, the airfoil carrier comprises flexible cooling configurations for adjustment to operational requirements, like base-load, peak-mode, partial load of the gas turbine.

[0169] FIG. 21 shows an assembled guide vane in the region of the outer platform, wherein the assembly between airfoil 100 and outer platform 200 resp. airfoil carrier 220 is made by a ceramic bush 230. This joint 231 may be mechanically loaded, no absolutely tightness is required. The remaining structure of the assembly corresponds essentially to the arrangement, as seen in FIGS. 4a-4d.

[0170] The outer platform 200 is cast, forged or manufactured in metal sheet or plate. The outer platform is consumable in relation to predetermined cycles, and frequently replaced at specified maintenance periods, and may be mechanically decoupled from the guide vane airfoil, wherein the outer platform may be supplementary mechanically connected to the airfoil carrier, using force closure elements, namely bolts. The outer platform may be coated with CMC or ceramic materials or may be manufactured by an isolation panel according to the attached claims.

[0171] FIG. 22 shows an assembled guide vane in the region of the inner platform 300, wherein the assembly between airfoil 100 and inner platform 300 is made by a ceramic bush 240. The joint 241 may be mechanically loaded, no absolute tightness is required. The remaining structure of the assembly corresponds essentially to the arrangement, as seen in FIG. 17.

[0172] The inner platform 300 is cast, forged or manufactured in metal sheet or plate. The outer platform is consumable, is replaced at specified maintenance periods, and may be mechanically decoupled from the guide vane airfoil, wherein the inner platform may be supplementary mechanically connected to the airfoil carrier, using force closure elements, namely bolts. The inner platform may be coated with CMC or ceramic materials or may be manufactured by an isolation panel according to the attached claims.

[0173] FIG. 23 shows a typical arrangement of the guide vane with a metallic shell 700. The elements shown in FIG. 20 are easily understood by a person skilled in the art, namely: 701 metallic shell; 702 spar; 703 airfoil carrier; 704 outer platform carrier; 705 outer platform hot gas liner; 706 inner platform hot gas liner; 707 inner platform carrier; 708 bolt and pin; 709 patch. The technical aspects of the elements result from the preceding figures and the associated description. The inner platform comprises a brazed/welding patch. The hot gas liner and hot gas carrier compose a brazed structure. The outer platform includes an impingement cooling. The outer platform comprises a brazed/welding structure. The spar comprises a sealing structure with respect to the airfoil. The outer platform includes securing/and rotating elements.