SEALING RING

Abstract

The present invention belongs to the technical field of sealing means used in combustion engines. In particular, the invention relates to sealing rings and, more in particular, to sealing rings used in aircraft turbomachinery.

Claims

1. A sealing ring adapted for insertion into a circumferential groove of a gas turbine engine, the circumferential groove being defined between two static elements of a compressor stage or a turbine stage of the gas turbine engine, the sealing ring (10) having a substantially annular shape, and comprising: two radial surfaces, namely an inner radial surface and an outer radial surface; and two side surfaces extending between the inner radial surface and the outer radial surface; wherein one of the radial surfaces is configured for abutting against a corresponding first groove surface or second groove surface of the circumferential groove arranged in the gas turbine engine; wherein one of the side surfaces is configured for abutting against a corresponding third groove surface of the circumferential groove arranged in the gas turbine engine; wherein: at least a portion of the radial surface configured for abutting against the corresponding first or second groove surface, and at least a portion of the side surface configured for abutting against the corresponding third groove surface, are coated with a physical vapour deposited (PVD) coating; wherein the PVD coating comprises a passivation layer, and wherein the passivation layer comprises at least one component configured for passivating the corresponding surface of the sealing ring; and wherein the sealing ring is configured to be arranged into the circumferential groove sealing a joint between the static elements.

2. The sealing ring according to claim 1, wherein the component of the passivation layer configured for passivating the corresponding surface of the sealing ring is an oxide or a ceramic material.

3. The sealing ring according to claim 2, wherein the component of the passivation layer configured for passivating the corresponding surface of the sealing ring is an aluminium oxide, a nitride or a carbide.

4. The sealing ring according to claim 1, wherein the component of the passivation layer configured for passivating the corresponding surface of the sealing ring is an alloyed aluminium oxide Al(M)O, wherein (M) is a metal.

5. The sealing ring according to claim 4, wherein the metal (M) is chromium.

6. The sealing ring according to claim 1, wherein the PVD coating comprises a base layer, wherein the base layer is arranged over the corresponding surface of the sealing ring and the passivation layer is arranged over the base layer.

7. The sealing ring according to claim 6, wherein the base layer comprises a nitride or a carbide.

8. The sealing ring according to claim 6, wherein the base layer comprises a multilayer.

9. The sealing ring according to claim 8, wherein the multilayer comprises a plurality of alternating layers of M and MX, wherein a first layer is M and a last layer is MX, and wherein M is a metal and X is carbon or nitrogen.

10. The sealing ring according to claim 1, wherein the PVD coating has a thickness of 2 m-30 m.

11. The sealing ring according to claim 1, wherein the base layer has a thickness of 0.5 m-5 m.

12. The sealing ring according to claim 1, wherein the passivation layer (15.2) has a thickness of 2 m-30 m.

13. The sealing ring according to claim 1, wherein the sealing ring is made of a nickel-based superalloy.

14. A gas turbine engine comprising a circumferential groove having an annular shape and a sealing ring according to any of the previous claims, the circumferential groove comprising: a first groove surface having a substantially circumferential shape; a second groove surface having a substantially circumferential shape with a greater radius than the first groove surface; and at least a third groove surface extending between the first groove surface and the second groove surface; wherein the sealing ring is arranged within the groove, such that: one of the radial surfaces of the sealing ring abuts against the corresponding first groove surface or second groove surface, and one of the side surfaces of the sealing ring abuts against a corresponding third groove surface; wherein the circumferential groove is defined between two static elements of a compressor stage or a turbine stage of the gas turbine engine, and wherein the sealing ring is arranged sealing a joint between said static elements.

15. The gas turbine engine according to claim 14, wherein at least one of the static elements is made of a nickel-based superalloy.

Description

DESCRIPTION OF THE DRAWINGS

[0081] These and other characteristics and advantages of the invention will become clearly understood in view of the detailed description of the invention which becomes apparent from a preferred embodiment of the invention, given just as an example and not being limited thereto, with reference to the drawings.

[0082] FIGS. 1A-1B These figures show schematic cross-sectional views of the implementation of a sealing ring as part of a gas turbine engine according to an embodiment of the invention.

[0083] FIGS. 2A-2B These figures show schematic cross-sectional views of the implementation of a sealing ring as part of a gas turbine engine according to another embodiment of the invention.

[0084] FIG. 3 This figure shows a schematic cross-sectional view of a portion of a surface of a sealing ring provided with a PVD coating according to an embodiment of the invention.

[0085] FIG. 4 This figure shows a schematic cross-sectional view of a gas turbine engine according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0086] Once the object of the invention has been outlined, specific non-limitative embodiments are described hereinafter.

[0087] FIGS. 1A-2B show schematic cross-sectional views of a circumferential groove (21) and a sealing ring (10) implemented as part of a gas turbine engine (20) according to different embodiments of the invention.

[0088] Specifically, FIGS. 1A-1B show a portion of an embodiment of a gas turbine engine (20) where it can be observed a schematic representation of the elements of said engine (20) provided to cooperate with a sealing ring (10) in order to prevent gas leakage (30) through a passage or joint (26) arranged in the gas turbine engine (20) between two static elements (27, 28), namely a first static element (27) and a second static element (28). These static elements (27, 28) shall be understood as static in that they do not rotate but allow relative displacement between them.

[0089] More specifically, in the embodiment shown in FIGS. 1A-1B a circumferential groove (21) can be observed arranged in a static element (27).

[0090] According to some embodiments of the invention, said static element (27) is part of a compressor stage or a turbine stage.

[0091] Although FIG. 1A schematically shows a portion of a cross section of the gas turbine engine (20) cut by a plane parallel to the longitudinal axis of the gas turbine engine (20), and perpendicular to the rotor blade discs as well as the guide vanes, it is understood that said circumferential groove (21) has an annular shape.

[0092] As it can be seen in the embodiment shown in FIG. 1A, for the coupling of the sealing ring (10) in the circumferential groove (21) and the provision of the sealing function, the circumferential groove (21) comprises a first groove surface (22) having a substantially circumferential shape, a second groove surface (23) having a substantially circumferential shape with a greater radius than the first groove surface (22), and two parallel third groove surfaces (24, 25) extending between the first groove surface (22) and the second groove surface (23). In the embodiment of FIG. 1A, the first groove surface (22) and the third groove surfaces (24, 25) are part of the first element (27), whereas the second groove surface (23) is part of the second element (28). Both elements (27, 28) define the circumferential groove (21).

[0093] As can be seen, all the first (22), second (23) and two third (24, 25) groove surfaces define a substantially rectangular cross sectional shape of the circumferential groove (21).

[0094] While FIG. 1A shows only the elements of the aero engine (20) provided to cooperate with a sealing ring (10), but not including said sealing ring (10), FIG. 1B shows a sealing ring (10) implemented in the circumferential groove (21) shown in FIG. 1A. Regarding the shape of the sealing ring (10), in the same manner as the circumferential groove (21), although FIG. 1B schematically shows a portion of a cross section of the gas turbine engine (20) cut by a plane parallel to the longitudinal axis of the gas turbine engine (20), and perpendicular to the rotor blade discs as well as the guide vanes, it is understood that said sealing ring (10) has a substantially annular shape.

[0095] As it can be seen in the rectangular cross-sectional view of the sealing ring (10) shown in FIG. 1B, the sealing ring (10) comprises an inner radial surface (11), an outer radial surface (12) which has a greater radius than the inner radial surface (11), and two parallel side surfaces (13, 14) extending between the inner radial surface (11) and the outer radial surface (12).

[0096] Regarding the coupling of the sealing ring (10) in the circumferential groove (21), as it can be seen, in the embodiment of FIG. 1B the outer radial surface (12) of the sealing ring (10) is shown abutting against the second groove surface (23) of the circumferential groove (21) and one of the two side surfaces (14) of the sealing ring (10) is shown abutting a corresponding third groove surface (25) of the circumferential groove (21).

[0097] As regards the materials of which both the sealing ring (10) and the static elements (27, 28) of the gas turbine engine (20) in which the circumferential groove (21) is provided, in the particular embodiment shown in FIG. 1B, both the sealing ring (10) and the static elements (27, 28) are made of a nickel-based superalloy.

[0098] According to the invention, in order to prevent adhesion between the sealing ring (10) and the part of the gas turbine engine (20) comprising the circumferential groove (21) in which the sealing ring (10) is implemented during operation, which would cause adhesive type wear and degradation of the surfaces, at least a portion of the surfaces (11, 12, 13, 14) of the sealing ring (10) abutting a corresponding groove surface of the circumferential groove (21) provided in the gas turbine engine (20) are coated with a physical vapour deposited (PVD) coating.

[0099] Said PVD coating works as a barrier that avoids the direct contact between the materials of the sealing ring (10) and the part of the gas turbine engine (20) comprising the circumferential groove (21) in which the sealing ring (10) is implemented, and therefore prevents adhesions and subsequent material degradation leading to a reduction of sealing function.

[0100] In this regard, in the embodiment shown in FIG. 1B, at least a portion of the outer radial surface (12) and at least a portion of the side surface (14) that abuts against a third groove surface (25) of the circumferential groove (21) are coated with a physical vapour deposited (PVD) coating. In an embodiment, the outer radial surface (12) and the side surface (14) are entirely coated with the PVD coating.

[0101] FIGS. 2A-2B show a schematic cross-sectional view of a circumferential groove (21) and a sealing ring (10) implemented as part of a gas turbine engine (20) according to another embodiment of the invention. As described in connection with FIGS. 1A-1B, FIGS. 2A-2B show a portion of another embodiment of a gas turbine engine (20) where it can be observed a schematic representation of the elements of said engine (20) provided to cooperate with a sealing ring (10) in order to prevent gas leakage (30) through a passage or joint (26) arranged in the gas turbine engine (20) between two static elements (27, 28), namely a first static element (27) and a second static element (28). These static elements (27, 28) do not rotate but one is movable with respect to the other.

[0102] In the embodiment of FIG. 1A, the first groove surface (22) and the third groove surfaces (24, 25) are part of the first element (27), whereas the second groove surface (23) is part of the second element (28). By contrast, in the embodiment of FIG. 2A, the second groove surface (23) and the third groove surfaces (24, 25) are part of the first element (27), whereas the first groove surface (22) is part of the second element (28). The first groove surface (22) has a substantially circumferential shape, the second groove surface (23) has a substantially circumferential shape with a greater radius than the first groove surface (22), and the two parallel third groove surfaces (24, 25) extend between the first groove surface (22) and the second groove surface (23).

[0103] While FIG. 2A shows only the elements of the gas turbine engine (20) provided to cooperate with a sealing ring (10), but not including said sealing ring (10), FIG. 2B shows a sealing ring (10) implemented in the circumferential groove (21) shown in FIG. 2A. As in the embodiment of FIG. 1B, for the embodiment of FIG. 2B the sealing ring (10) has a substantially annular shape. Moreover, the configuration of the sealing ring (10) according to a rectangular cross-sectional view as shown in FIG. 2B is the same as in the embodiment of FIG. 1B. That is, the sealing ring (10) of this FIG. 2B comprises an inner radial surface (11), an outer radial surface (12) which has a greater radius than the inner radial surface (11), and two parallel side surfaces (13, 14) extending between the inner radial surface (11) and the outer radial surface (12).

[0104] In the embodiment of FIG. 2B, the inner radial surface (11) of the sealing ring (10) is shown abutting against the first groove surface (22) of the circumferential groove (21) and one of the two side surfaces (14) of the sealing ring (10) is shown abutting a corresponding third groove surface (24) of the circumferential groove (21). In the embodiment shown in FIG. 2B, at least a portion of the inner radial surface (11) and at least a portion of the side surface (14) that abuts against a third groove surface (27) of the circumferential groove (21) are coated with a physical vapour deposited (PVD) coating. In an embodiment, the inner radial surface (11) and the side surface (14) are entirely coated with the PVD coating.

[0105] In FIGS. 1B and 2B the PVD coating is schematically depicted with thick black line.

[0106] As to the features of said PVD coating coated over the surfaces (12, 14) of the sealing ring (10) shown in FIG. 1B, these are described in detail with reference to FIG. 3.

[0107] In particular, FIG. 3 shows a schematic cross-sectional view of a portion of the outer radial surface (12) of the sealing ring (10) shown in FIG. 1B cut by a plane perpendicular to said outer radial surface (12).

[0108] Although reference is made to the outer radial surface (12), the following description of the features of the PVD coating on said surface (12) applies to the PVD coating coated over any other surface (11, 12, 13, 14) of the sealing ring (10) according to any of the embodiments of FIGS. 1B-2B.

[0109] In particular, the PVD coating shown in FIG. 3 comprises a base layer (15.1) coated over the outer radial surface (12) of the sealing ring (10), said base layer (15.1) comprising CrN, and having a thickness of 0.5 m-5 m. As can be seen, the base layer (15.1) is depicted with a pattern of consecutive crosses.

[0110] Additionally, as can be seen, a passivation layer (15.2) is provided over the base layer (15.1), the passivation layer (15.2) comprising at least one component configured for passivating the corresponding surface, this is, the outer radial surface (12) of the sealing ring (10). In particular, in the embodiment of the PVD coating shown in FIG. 3, the component of the passivation layer (15.2) configured for passivating the outer radial surface (12) of the sealing ring (10) is an alloyed aluminium oxide Al(M)O, wherein, in the particular embodiment shown, (M) is chromium. Preferably, the passivation layer (15.2) has a thickness of 2 m-30 m.

[0111] The passivation layer (15.2) is depicted with a pattern of parallel oblique stripes.

[0112] FIG. 4 shows a portion of a gas turbine engine (20) according to an embodiment of the invention.