The present invention relates to a tile for covering combustion chambers, in particular for gas turbines, and to a combustion chamber comprising said tile.

BACKGROUND ART

As is known, the inner walls of combustion chambers of energy production power gas turbines require effective thermal protection because during combustion, they are exposed to high-temperature hot and often highly corrosive gases .

It is known to use tiles made of ceramic material for this purpose, and to apply them for example, on the structure walls of the combustion chamber. In general, ceramic materials are potentially suitable for this application because they provide good thermal protection and have low conductivity.

Tiles are generally coupled to the inner face of the combustion chamber by means of retaining elements, which are configured to hold the tiles along the two lateral opposing faces .

A tile of this type is described in document EP 0558540.

However, serious damage of the inner face of the combustion chamber (normally defined "Hub") to which the tiles are coupled becomes apparent during use. Such damage is determined by unexpected movements of the tiles of the combustion chamber, in particular along the flow direction (toward the gas turbine) .

The unexpected movement of the tiles indeed exposes large portions of the inner face comprised between one tile and the other to high temperatures thus causing burning and formations of cracks.

A solution to this type of problem is described in document US 8104287.

However, such a solution requires changing the structure of the tile and further changing the structure of the retaining elements. This involves changing both the moulds for making the tile and changing the moulds for the retaining elements and the type of processing thereof.

In particular, processing the retaining elements is very industrious, as they are generally made of metal material .

DISCLOSURE OF INVENTION

It is thus one object of the present invention to provide a tile for covering combustion chambers, in particular for gas turbines, capable of avoiding the drawbacks of the tiles of the known art.

In particular, it is one object of the invention to make a tile in a simple and affordable manner that is stable during use and does not expose portions of the inner face of the combustion chamber to the destructive action of high temperatures .

In accordance with such objects, the present invention relates to a tile for covering combustion chambers, in particular for gas turbine energy production power plants, comprising a main body, which extends along a longitudinal axis and is provided with:

— a main face, which faces, in use, the inner of the combustion chamber,

— two lateral opposing faces, each of which is provided with a groove extending substantially along the longitudinal axis and adapted to be engaged by at least a respective retaining element configured to couple the tile to an inner face of the combustion chamber so as to block movements of the tile along a direction orthogonal to the longitudinal axis;

— a rear face, adapted, in use, to be coupled to the inner face of the combustion chamber; the rear face being provided with a coupling element, which protrudes from the rear face and is configured to engage a respective seat of the inner face of the combustion chamber so as to block movements of the tile along the longitudinal axis.

It is one further object of the present invention to make a combustion chamber for a gas turbine energy production power plant that is reliable and in which the movements of the tiles are reduced.

In accordance with such objects, the present invention relates to a combustion chamber, in particular for gas turbine energy production power plants, provided with a casing, which defines a combustion area; the casing comprising an inner face, which is provided with at least one seat and with an inner covering, which covers the inner face and comprises at least one tile according to any one of the claims from 1-5.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will become more apparent from the following description of a non-limiting embodiment thereof, with reference to the figures of the accompanying drawings, in which :

- figure 1 is a diagrammatic view of a gas turbine energy production power plant comprising a combustion chamber according to the present invention; - figure 2 is a sectional view, with parts removed for clarity, of the combustion chamber according to the present invention;

- figure 3 is a first perspective view, with parts removed for clarity, of a tile for covering combustion chambers according to the present invention;

- figure 4 is a second perspective view, with parts removed for clarity, of the tile in figure 3;

- figure 5 is a perspective view of a detail of the combustion chamber according to the present invention, with parts removed for clarity.

BEST MODE FOR CARRYING OUT THE INVENTION

Numeral 1 in figure 1 indicates an energy production power plant comprising a compressor 3, a combustion chamber 4, a gas turbine 5 and a generator 7, which transforms the mechanical power supplied by turbine 5 into electric power to be supplied to an electric network 8 connected to generator 7 by means of a switch 9.

A variant which is not illustrated provides that plant 1 is of the combined-cycle type and in addition to comprising the gas turbine 5 and generator 7, it also comprises a steam turbo assembly.

The gas turbine 5 extends along a longitudinal axis A and is provided with a shaft 13 (it also extending along axis A) to which compressor 3 and generator 7 are also connected .

Compressor 3 is preferably a multi-step axial compressor. In particular, compressor 3 extends along axis A and comprises an air intake 14 and an inlet stage 15 with variable geometry. The inlet stage 15 comprises a plurality of inlet guide vanes 16 (diagrammatically shown in figure 1), commonly called IGV (Inlet Guide Vane), whose tilt may be changed to regulate a flow rate of air drawn in from compressor 3.

With reference to figure 2, the combustion chamber 4 is provided with a casing 20, which defines a combustion area .

Preferably, the combustion chamber 4 is of annular type and has a substantially toroidal shape.

Casing 20 has a substantially annular shape and is provided with an inner covering 21, defined by a plurality of tiles

22 made of refractory material, which are arranged in adjacent columns.

With reference to figure 3, the tiles 22 comprise a main body 23, which extends along a longitudinal axis B and is preferably quadrangular in shape.

The main body 23 is provided with a main face 24, which is facing, in use, the inner of the combustion chamber 4, two lateral opposing faces 25, which are provided with a longitudinal groove 26 and a rear face 27, respectively, which rear face 27 is adapted to be coupled to a respective portion of an inner face 28 of casing 20 (figure 5) . The longitudinal grooves 26 extend substantially along axis B and are substantially U-shaped.

With reference to figure 4, the tiles 22 are coupled to the inner face 28 of casing 20 (figure 5) by means of retaining elements 29. In the non-limiting example described and shown herein, each tile 22 is coupled to the inner face 28 of casing 20 by means of four retaining elements 29.

Each retaining element 29 is coupled to the inner face 28 of casing 20 and to the respective tile 22 so as to block movements of tile 22 along a direction orthogonal to the longitudinal axis B.

In particular, each retaining element 29 is configured to engage a respective groove 26 of tile 22.

With reference to figure 5, the inner face 28 of casing 20 is provided with two seats 31, which extend parallel to each other and are intended to accommodate the retaining elements 29. In particular, each seat 31 is intended to accommodate two retaining elements 29 configured to engage grooves 26 opposing tile 22.

The seats 31 are preferably defined by a longitudinal groove having a substantially U-shaped section.

With reference to figure 4, each retaining element 29 comprises a plate 32 provided, at a first end, with a coupling hole 33 for coupling to the inner face 28 and, at a second end, with a fin 34 having a substantially U-shaped section .

Each plate 32 is coupled to the bottom wall of the respective seat 31 of the inner face 28 so that, in use, fin 34 protrudes from the respective tile 22 and engages the respective longitudinal groove 26 of tile 22.

With reference to figures 3, 4 and 5, the rear face 27 of each tile 22 is provided with a coupling element 35, which protrudes from the rear face 27 and is configured to engage one of the seats 31 made along the inner face 28 of casing 20.

In particular, the coupling element 35 is shaped so as to engage one of the seats 31 so as to ensure tile 22 does not move along its longitudinal axis B.

Preferably, the coupling element 35 is substantially parallelepiped shaped and has an axial height, intended as the length measured along the longitudinal axis B, such as to allow the insertion in seat 31 with the lowest play.

Thereby, the retaining elements 29 block the movements of tile 22 along a direction orthogonal to the longitudinal axis B, while by engaging the respective seat 31, the coupling element 35 blocks the movements of tile 22 along the direction parallel to the longitudinal axis B. Therefore, the presence of the coupling element 35 contributes to reducing the movements along axis B and hence to reducing the portions of the inner face 28 comprised between one tile 22 and the other which are exposed to high temperatures thus causing burning and formations of cracks.

It is understood that the coupling element 35 may have any different shape capable of ensuring the blockage of the movements of tile 22 along the direction parallel to the longitudinal axis B.

Considering the configuration in the non-limiting embodiment described and illustrated herein, in which the tiles 22 are mounted along the inner face 28 of casing 20 of a combustion chamber 4 of the annular type, the presence of the retaining elements 29 blocks the movements of the tiles 22 along a circumferential direction about axis A of plant 1, while the presence of the coupling elements 35 blocks the movements of the tiles 22 along the flow direction of burnt gases that laps the tiles 22.

Advantageously, tile 22 according to the present invention resolves the problem related to uncontrolled axial movements in a simple and affordable manner.

Due to the present invention, activities of extraordinary maintenance are indeed reduced on macro components of the combustion chamber 4 with significant savings in terms of labour and repair time during scheduled maintenance .

The reduction of intervention times is of fundamental importance for the plant manager, who, due to the present invention, will observe the reduction of the overall stop time of plant 1.

Moreover, the reduction of cracks and burns determines a reduction of the consumption of spare parts, with apparent economic advantages.

Finally, the tiles 22 made according to the present invention may be applied to existing combustion chambers without requiring any adaptations. The coupling element 35 indeed engages a seat 31 already present on all plants in which the use is provided of the retaining elements 29 for coupling the tiles 22.

Finally, it is apparent that modifications and variants may be made to the tile and to the combustion chamber herein described without departing from the scope of the appended claims.