Sealing gasket for turbomachine

Abstract

This document presents an annular sealing gasket (10) comprising a plurality of gasket sectors (30, 60, 62) distributed circumferentially around a longitudinal axis (A), each gasket sector (30, 60, 62) comprising an inner ring sector (30) connected to an outer ring sector (60) by a return member (62), the sealing gasket (10) further comprising a sealing member (32, 34, 38, 40) comprising an annular row of blades (32) held axially against the inner (30) and outer (60) ring sectors by a retaining cup (40). (See Figure 4 in the abstract.)

Description

Title of the invention: Sealing gasket for turbomachine technical field

[0001] This disclosure relates to the design of a seal for a turbomachine and to a turbomachine comprising such a seal. Prior art

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive and more environmentally friendly aeronautical components and products, the integration and use of which in civil aviation result in moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] In this context, engine efficiency is constantly being improved, which sometimes impacts the temperature of the gases or structural elements downstream of the combustion chamber. Controlling turbine temperatures is essential for reasons of mechanical strength and to control expansion deformations.

[0005] Patent document FR 3 080 406 Al describes a turbine distributor in which the blades are hollow and are adapted to receive a flow of air cooling the blades and taken from the compressor.

[0006] The turbine cooling air can be drawn downstream of the compressor and radially below the combustion chambers. This airflow passes through three seals: a high-pressure downstream compressor seal, called a "CDP" (compressor discharge pressure); an internal seal, called a "FIS" (forward inner seal); and an external seal, called a "FOS" (forward outer seal). These seals are generally labyrinth seals. They are formed of blades arranged on the rotor which cooperate with an abradable element on the stator. The abradable element may have a honeycomb-type structure.

[0007] The drawback of this type of seal lies in the fact that the friction of the blades on the abradable material tends to damage the abradable material and consequently increase the clearance between the rotor and stator. This leads to an increase in the airflow through the seals. Depending on the seal in question (CDP, FIS, FOS), this means an increase or decrease in the airflow supplied to the turbines and therefore a deviation from an optimized target airflow value. Thus, the increased clearance between these seals and the rotors can have two major consequences: a reduction in the turbomachine's efficiency and insufficient turbine cooling.

[0008] Therefore, there is a need to ensure consistent flow rates through the seals throughout their service life. Summary

[0009] The present invention aims to provide a turbomachine sealing gasket that allows control of the cooling air flow supplied to the turbines, independently of its lifespan.

[0010] For this purpose, the present document relates to an annular sealing joint comprising a plurality of sealing sectors arranged circumferentially around a longitudinal axis, each sealing sector comprising an inner ring sector connected to an outer ring sector by a return member, the sealing joint further comprising a sealing member comprising an annular row of blades held in axial support against the inner and outer ring sectors by a retaining cup.

[0011] This design minimizes radial air leakage above the inner ring sector without hindering the radial movement of the inner ring sector. Thus, the clearance between the seal and the rotor can be controlled by means of a simple and reliable design.

[0012] Such a seal architecture differs from a labyrinth seal. The inner ring sector is radially movable and has an internal interface with a rotor. The bearing capacity of the inner sector and the return element ensure that a predefined clearance is maintained with the internal rotor.

[0013] It is evident that the sealing of the gasket is not a strict seal in the sense that air could not pass through the gasket, but a relative seal, the purpose of the gasket being to allow a controlled amount of air to pass through, but only between the gasket and the rotor. The sealing element ensures that no air passes between the inner ring sector and the outer ring sector.

[0014] It is understood that the predefined clearance is a "target" clearance, and that it is possible for the clearance to vary slightly around the predefined clearance value under certain operating conditions of the seal. When the seal is in its equilibrium position, the predefined clearance ensures that the airflow through the seal is the desired airflow. However, if the clearance increases or decreases, the seal will return to the predefined clearance relative to a spring-like behavior of the internal ring sectors, ensured in particular by the return elements and the airflow.

[0015] More specifically, if the clearance between the seal and the rotor becomes smaller than the predefined clearance, the air friction under the inner ring sector tends to move the inner ring sector so as to increase the clearance. Conversely, if the clearance between the seal and the rotor becomes larger than the predefined clearance, the return element exerts a force greater than the lift of the inner ring sector, the inner ring sectors then returning to their equilibrium positions, i.e., to the predefined clearance.

[0016] This mechano-aerodynamic balance which regulates a predefined clearance also makes it possible to avoid any contact between the rotor and the seal, thus avoiding the wear problem encountered with conventional labyrinth seals.

[0017] The "circumferential distribution" of the joint sectors means that each joint sector defines a portion of the joint's circumference, and that all the joint sectors together make up the complete joint. Optionally, the distribution is regular, and each joint sector then represents an equal portion of the sealing joint's circumference.

[0018] The terms "internal" and "external," or interchangeably "inside" and "outside," refer to a radial position relative to the central axis of the joint around which the joint sectors are arranged. "Upstream" and "downstream" are to be understood in the principal direction of flow in a turbomachine.

[0019] According to one embodiment, in which the blades have openings aligned with blind holes formed in the outer ring sectors, the sealing member comprising pins having a head and a stem, each stem passing through one of the openings of the blades and being inserted into the corresponding blind hole, the retaining cup holding the blades against the inner and outer ring sectors by means of the pin heads.

[0020] Leaks via the pawns are avoided by the fact that the holes are blind.

[0021] The pins are optional and the retaining cup can be in direct contact with the blades.

[0022] In one variant, the holes are through holes.

[0023] According to one embodiment, the pins are mounted floating in the blind holes of the outer ring sectors.

[0024] The term "floating" means that the pins are not fixed to the blades or the ring sectors. They are held in position by the upstream retaining cup and the downstream outer ring sector.

[0025] In one embodiment, the pins are fixed to the outer ring sector. The pins can be fixed to the ring sector by welding, threading, or circlip, among other methods. The pins can thus apply an axial force to the blades even in the absence of the retaining cup, which has become optional.

[0026] According to one embodiment, each pin head has a spherical cap. The pin is therefore as light as possible and the contact between the retaining cup and the pin is point contact, allowing, by design, for precise control of the pressure applied to the blades.

[0027] According to one embodiment, the retaining cup is attached to an external radial flange for securing the annular sealing ring to a housing. Optionally, axial fasteners pass through the retaining cup, the external radial flange, and an internal radial flange of the housing. This configuration allows, in particular, for the sharing of fasteners and thus results in a simple, reliable, lightweight, and compact design. The axial fasteners can be screws or bolts.

[0028] According to one embodiment, the retaining cup is formed of a sheet metal bent into a hairpin shape having two flat portions perpendicular to the longitudinal axis and a connecting portion describing a cylinder around the longitudinal axis; or in which the retaining cup is formed of a plurality of sheets metal bent into a hairpin shape each having two flat portions perpendicular to the longitudinal axis and a connecting portion describing a sector of a cylinder around the longitudinal axis.

[0029] Thus, the retaining cup can extend over 360° around the axis or be sectored, continuously or discontinuously (the sectors are circumferentially spaced). The cup sectors can cover one or more ring sectors, one or more pins (for example, 2), and / or one or more blades.

[0030] According to one embodiment, blade covers at least partially cover two circumferentially adjacent blades. These blade covers ensure a seal between two adjacent blades.

[0031] According to one embodiment, the plurality of blades comprises a blade mounted axially opposite each joint sector. Thus, the plurality of blades consists of one blade for each joint sector.

[0032] According to one embodiment, each inner ring sector comprises an outer lip with a front surface on which the axial support of the blades is made against the inner ring sectors.

[0033] In one embodiment, the sealing joint comprises between 8 and 20 sealing sectors.

[0034] This range of values ​​constitutes a good compromise between too few sectors, synonymous with sectors that are heavy for the return mechanisms, and too many sectors, synonymous with many inter-sector gaps and therefore potential air leaks.

[0035] In one embodiment, the outer ring sectors of a sealing gasket may be a single piece, for example a ferrule. In other words, there is no physical separation between two circumferentially successive outer ring sectors.

[0036] In one embodiment, such a ferrule may be monolithic, that is, made in a single piece without joining. In such a case, an angular portion of the ferrule may be considered as a sector of the outer ring.

[0037] The invention also relates to a method of assembling an annular sealing gasket according to one of the embodiments mentioned above, the method comprising the steps of: providing an assembly comprising a plurality of gasket sectors distributed circumferentially around a longitudinal axis, each gasket sector comprising an inner ring sector connected to an outer ring sector by a return member; positioning blades in axial support against the inner and outer ring sectors; then positioning a retaining cup applying a force on the blades to maintain contact between the blades and the inner and outer ring sectors.

[0038] Optionally, the blade covers and pins are also assembled to the assembly and the support provided by the retaining cup is indirect on the blades.

[0039] The invention also relates to a turbomachine comprising: a high-pressure compressor; a combustion chamber; a high-pressure turbine; a first, a second, and a third sealing ring; and a cooling air supply circuit to the high-pressure turbine, the air supply circuit comprising an air inlet downstream of the high-pressure compressor, a duct separated from the inlet by the first sealing ring, a housing separated from the duct by the second sealing ring, an air injector opening into the housing, a purge outlet separated from the housing by the third sealing ring, and an air outlet from the housing directing the airflow to the high-pressure turbine, at least one of the first, second and third sealing joints conforming to one of the embodiments set out above.

[0040] Depending on the position envisaged, the first seal is a seal downstream of the high-pressure compressor (called "CDP" for "compressor discharge pressure" in English), the second seal is a forward inner seal (called "FIS" for "forward inner seal" in English) and the third seal is a forward outer seal (called "FOS" for "forward outer seal" in English).

[0041] It has been found that the seals of the invention allow better control of the play during their lifetime than labyrinth seals, and thus ensure maintenance of the performance of the turbomachine and efficient cooling of the turbines throughout the life of the seal. Brief description of the drawings

[0042] Other features, details and advantages will become apparent from reading the detailed description below, and from analyzing the accompanying drawings, on which:

[0043] [Fig.1] is a schematic cross-sectional view of a turbomachine;

[0044] [Fig.2] is a cross-sectional view of a turbine cooling circuit;

[0045] [Fig.3] is a front view of a sealing joint according to the invention;

[0046] [Fig.4] is a cross-sectional view of a joint sector;

[0047] [Fig.5] is a partial view of the blade and blade cover assembly. Description of the implementation methods

[0048] The figures schematically depict various aspects of the invention. The dimensions are not shown to scale: some dimensions are enlarged to facilitate reading the drawings and understanding the phenomena involved. The term "approximately," used to describe the dimensions of the various elements, is to be understood as synonymous with a tolerance of + / - 10%.

[0049] The axial direction is that of the longitudinal axis of the turbomachine, denoted A. The radial direction is perpendicular and coplanar to the direction A. The circumferential or tangential direction is orthogonal to the axial direction and to the radial direction.

[0050] The present invention is preferably related to turbomachinery for aircraft. As such, [Fig. 1] schematically represents, in cross-section along a vertical plane passing through its longitudinal axis A, a turbofan engine 1. From upstream to downstream, along the airflow path, it comprises a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, and a low-pressure turbine. 7. It is understood that the invention is not limited to a turbomachine specifically with this structure.

[0051] The air entering the turbomachine is cold. It is compressed by compressors 3 and 4 and its temperature rises to approximately 500-600°C. At the outlet of the combustion chamber 5, the air is at a temperature of approximately 1500 to 2000°C. The turbines 6 and 7 therefore receive hot air and are thus subject to deformation and thermal wear. One way to regulate the temperature of the turbines is to draw cooler air from below the combustion chamber 5 and at the level of the last stages of the compressor 4, and to route this air downstream to cool the turbines.

[0052] Figure 2 represents a portion of the turbomachine of Figure 1, and in particular the combustion chamber and sealing gaskets.

[0053] In the embodiment shown, the turbomachine portion has three seals: a seal 10 downstream of the high-pressure compressor (“CDP”), an internal seal before 12 (“FIS”), and an external seal before 14 (“FOS”).

[0054] Figure 2 is only an example of a configuration for a cooling path of air in a turbomachine, and the man skilled in the art will be able to identify the respective CDP, FIS and FOS seals in other cooling circuit geometries.

[0055] In the illustrated embodiment, an air inlet 9 allows air 16 to be drawn downstream of the last compressor disc. The air 16 drawn downstream of the last compressor disc first passes through the sealing gasket 10, which is located radially below the inlet of the combustion chamber 5.

[0056] The air 16 continues its path in a conduit 11 which can be annular around the axis A.

[0057] The air then passes through a second seal (front internal seal) 12 and opens into a housing 13 arranged between the second seal 12 and a third seal (front external seal) 14.

[0058] Air is also taken from under the combustion chamber 5. Air injectors 15 from a cavity 17 under the combustion chamber open into the housing 13.

[0059] The air 16 from the compressor and that from the injectors 15 meet at the housing 13. This air is then directed to a cooling circuit 18 of the first stage of the turbine 6 via an outlet 19 of the housing 13. The seal 14 allows regulation of an air outlet from the housing 13 to a purge circuit 20, axially positioned between a distributor 6.1 and the first moving wheel of the turbine 6.

[0060] The flow 18 is intended to cool the turbine and in particular to cool the hollow blades of the turbine 6.

[0061] The quantities of air regulated by the seals 10, 12, 14 are dictated by the clearance between these seals and a respective internal surface 22 opposite the seals. In the embodiment shown, the surface 22 opposite the seals 10, 12, 14 is an external surface of a rotor assembly.

[0062] In the following, the sealing gasket of the invention will be described with the number 10, but it should be noted that what is described for this gasket can also, or alternatively, be applied to the other sealing gaskets 12, 14.

[0063] Fig. 3 shows part of a joint 10 in front view, perpendicular to direction A.

[0064] The joint 10 is composed of sectors which are distributed in a circumferential direction T around the axis A. Each sector counts as an angular part of a ring describing 360° around the axis A. Each sector comprises an internal annular sector 30, an external annular sector 60, and a return member 62. The return member 62 is linked to the internal annular sector 30 at a base 64, and the return member 62 is linked to the external annular sector 60 at a base 66.

[0065] The joint 10 can be formed from 8 to 20 sectors.

[0066] The outer ring sectors 60 can together form a single ring. The sectoring is in this case purely geometric. Alternatively, the outer ring sectors 60 can be formed from separate pieces assembled together.

[0067] The return member 62 may be formed of two blades of a thickness designed to give them a predetermined elasticity, for example between 0.7 and 2.0 mm. The total thickness of the return member may be between 2.5 and 5.0 mm. It is understood that another number of blades (1, 3, 4) or another elastic spring technology may be used.

[0068] The inner ring sectors 30 are spaced from each other by a distance e. This distance is exaggerated in [Fig. 3]. This distance may be less than 0.3 mm.

[0069] The assembly shown in [Fig.3] can be monobloc, that is to say that the inner ring sectors 30, the outer ring sectors 60, the return members 62 and the bases 64, 66 can be formed from a single piece.

[0070] The inner ring sectors 30 are spaced from a rotor 22 by a clearance j. The seal 10 is designed to ensure a predefined clearance j. The predefined clearance can be between 0.1 and 1.0 mm. This clearance corresponds to a target airflow for a given engine speed or load.

[0071] If, during the operation of the turbomachine, the clearance j becomes too large, the return member 62 will tend to apply a force radially towards the axis A to reduce the clearance j. Conversely, if the clearance j becomes too small, the airflow passing through the interface between the inner ring sector 30 and the rotor 22 will increase in pressure and will tend to move the inner ring sector 30 away from the axis A.

[0072] In [Fig.3], blades which cover the space between the inner ring sectors and the outer ring sectors are not shown.

[0073] Figure 4 shows a cross-sectional view of a sector of the seal 10 in a plane containing axis A. The upstream side is on the left and the downstream side is on the right. The cold pressurized air is to the left of the seal 10. The seal 10 is positioned between a rotor 22 at the bottom and a stator housing at the top.

[0074] This notably shows the inner ring sector 30, which has an outer surface 30.1 and an inner surface 30.2. The inner surface 30.2 is separated from the rotor 22 by the clearance j. The inner ring sector 30 may have an upstream portion 30.3 having a radial thickness less than a downstream portion 30.4. The upstream portion 30.3 may extend axially upstream of the outer ring sector 60. The return member 62 may be exclusively supported by the downstream portion 30.4.

[0075] The inner ring sector 30 may have an outer lip 30.5 which may be carried by the downstream portion 30.4. An edge 30.51 of the outer lip 30.5 may form a high point of the inner ring sector 30. The outer lip 30.5 has a frontal surface 30.52.

[0076] To prevent pressurized air upstream of the seal 10 from passing uncontrollably through the seal between the inner ring sector 30 and the outer ring sector 60, an annular row of blades 32 is supported against the inner ring sectors 30 and outer ring sectors 60 by a retaining cup 40. A blade 32 is visible in section on [Fig.4].

[0077] The blades 32 are supported on the front surface 30.52 of the inner ring sector 30. The contact between the blade 32 and the front surface 30.52 is characterized by an annular area (viewed from the front as in [Fig.3]) of radial height d. This radial height d can be small enough to limit friction due to the radial displacement of the inner ring sector 30 but large enough to maintain a seal regardless of the radial position of the inner ring sector 30. Thus, d can be between 0.5 and 3 mm.

[0078] On the external side, the outer ring sector 60 has a body 60.1 having a front surface 60.2 with an internal end edge 60.3. The contact between the blade 32 and the front surface 60.2 of the outer ring sector 60 is characterized by an annular area of ​​radial height D. The blade 32 can extend radially beyond the front surface 60.2 and thus be in contact over its entire front surface 60.2 with the outer ring sector 60. The radial height D can be at least 3 times greater than the radial height d.

[0079] Thus, the blade 32 radially overlaps the entire return member 62 and radially overlaps part of the inner ring sectors 30 and outer ring sectors 60.

[0080] The blade 32 can have a thickness greater than 0.2 mm. It can extend radially over a height of approximately 15 mm + / - 10%.

[0081] The blades 32 form an annular row, that is to say a set sharing the same axial position and distributed circumferentially around the axis A (see also [Fig.5]).

[0082] Between each pair of blades 32 there is a small gap allowing the free movement of the internal ring sectors 30 under the influence of thermal expansion. The gap may have a circumferential width of less than 0.4 mm.

[0083] The blade 32 can be covered by a blade cover 34 which circumferentially overlaps two adjacent blades 32. In other words, viewed radially, the blades 32 and blade covers 34 are arranged in a staggered pattern.

[0084] The blades 32 and blade covers 34 can have the same radial height of approximately 15 mm.

[0085] In order to support the blade 32 and the possible blade cover 34 against the ring sectors 30, 60, a possible pin 38 and a retaining cup 40 are provided.

[0086] The pin 38 of the sealing member may include a head 38.1 and a rod 38.2. The head 38.1 may be in contact with a blade 32 or a blade cover 34. The rod 38.2 may extend parallel to the axis A. It may pass through the blade 32 and / or the blade cover 34 and / or the outer ring sector 60. It may be inserted into a blind hole 60.4 of the outer ring sector. Preferably, the rod 38.2 is mounted floating in the blind hole 60.4 of the outer ring sector 60. The pin 38 is held fixed in axial translation by the retaining cup 40 and the outer ring sector 60. The cup 40 holds the blades 32 against the ring sectors 30, 60 via the heads 38.1 of the pins 38.

[0087] The diameter of the rod 38.2 can be approximately 1 mm and its length can be greater than 20 mm. The diameter of the head 38.1 can be greater than 5 mm. The head 38.1 of the pin can have a spherical cap to form a point contact with the retaining cup 40.

[0088] The blade 32, the optional blade cover 34 and the outer ring sector 60 can be drilled to allow the passage of the rod 38.2 of the pin 38.

[0089] Thus, the outer ring sector 60 has a blind hole 60.4 parallel to the axis A and with a diameter slightly greater than the diameter of the stem 38.2 of the pin 38. For example, the diameter may be about 1.10 mm.

[0090] An external radial flange 60.5 is provided for fixing the seal 10 to an internal radial flange 24.1 of the housing 24. The external radial flange 60.5 can be one piece with the external ring sectors 60.

[0091] The retaining cup 40 can be attached to the flange 60.5. The retaining cup 40 can be formed from a flat sheet metal bent into a hairpin shape and having two portions parallel planes 40.1, 40.2. The plane portions 40.1, 40.2 can be perpendicular to the longitudinal axis A. One of the plane portions 40.1 can completely cover the head 38.1 of the pin 38: the internal radial end 40.4 of the retaining cup can be at an approximately median radial position of the blades 32. The two plane portions 40.1, 40.2 are connected to each other by a connecting portion 40.3 which can describe a cylinder around the longitudinal axis A.

[0092] The retaining cup 40 can be fixed to the outer ring sector 60 via axial fixing elements 70. These can pass through the retaining cup 40, the radially external flange 60.5 of the seal 10 and the flange 24.1 of the housing 24. The flat portion 40.2 of the cup is thus affixed and held against the flange 60.5. The cup can have a sheet metal thickness of approximately 1 mm.

[0093] The retaining cup 40 is subjected to pressurized air on its left and presses against the pin 38 on its right. The retaining cup 40 also helps to reduce the viscous friction of the air on the screw 70 and on the pins 38.

[0094] The retaining cup 40 can be formed from a single sheet or from several sectors of sheets 40 distributed circumferentially, joined or spaced from each other, each sector having two flat portions 40.1, 40.2 and a connecting portion 40.3 describing a cylindrical sector.

[0095] The pin 38 can pass through openings provided in the blade 32 and the blade cover 34. [Fig. 5] shows two blades 32 from the annular row of blades 32 (which together describe 360° around the axis A). The joint 10 can comprise as many blades 32 as there are internal ring sectors 30. The blades 32 can respectively cover each internal ring sector 30. Alternatively, there are more blades 32 than sectors 30, and each ring sector 30 therefore sees two or three blades 32. Alternatively, one blade 32 can cover more than one internal ring sector 30.

[0096] A blade cover 34 is also shown, covering the gap between the two blades 32 (gap shown by a dashed line in [Fig. 5]). The blade cover 34 covers at least two circumferentially adjacent blades 32. Each blade 32 has two openings 32.1 in a radially superior region near the circumferential ends of the blades 32. The blade cover 34 has two openings 34.1 in a radially superior region near the circumferential ends of the blade cover 34.

[0097] The openings of the blades 32 and the blade cover 34 coincide to allow the pawn 38 to pass through these openings 32.1, 34.1.

[0098] In the mounted position, the openings 32.1, 34.1 are aligned with the blind hole 60.4 ( [Fig.4]) of the outer ring sector 60.

[0099] The diameter of the openings 32.1, 34.1 can be equal to that of the orifice 60.4, i.e. be slightly greater than the diameter of the rod 38.2 of the pin 38.

[0100] The circumferential width of the blade cover 34 may be smaller than the circumferential width of the blades 32, the ratio being between 0.2 and 0.5.

[0101] Also, a larger or smaller number of pawns can be chosen to hold the blades.

[0102] With reference to figures 4 and 5, the procedure for assembling the seal in the turbomachine can take place as follows: the entire inner ring sector 30, outer ring sector 60 and return member 62, which may be one piece, is supplied; the blades 32 are placed in contact with the front surfaces 30.52, 60.2; the optional blade cover 34 is arranged to cover the gap between two adjacent blades 32; the optional pin 38 is inserted into the hole(s) provided for this purpose, and then the retaining cup is fixed to the outer ring sector.

[0103] To do this, the assembly can be placed horizontally, that is to say with the axis A vertical.

[0104] The screw(s) 70 can be inserted into the retaining cup 40 before the cup and screw assembly is slid axially so as to penetrate the screw(s) 70 into the flange 60.5. The assembly can then be slid axially against a fixing flange of the housing 24 to place a nut (visible in [Fig.4]).

[0105] Although [Fig.4] shows a pin, this is optional and the cup can take a different shape (its end 40.4 can be inclined or stepped) to directly press on the blades 32 and / or counter-blades 34.

Claims

Demands

1. An annular sealing gasket (10, 12, 14) comprising a plurality of gasket sectors (30, 60, 62) arranged circumferentially around a longitudinal axis (A), each gasket sector (30, 60, 62) comprising an inner ring sector (30) connected to an outer ring sector (60) by a return member (62), the sealing gasket (10, 12, 14) further comprising a sealing member (32, 34, 38, 40) comprising an annular row of blades (32) held axially against the inner (30) and outer (60) ring sectors by a retaining cup (40), the blades (32) having openings (32.1) aligned with blind holes (60.4) formed in the outer ring sectors (60), the sealing member (32, 34, 38, 40) comprising pawns (38) having a head (38.1) and a stem (38.2), each stem (38.2) passing through one of the openings (32.1) of the blades and being inserted into the blind hole (60.4) corresponding, the retaining cup (40) holding the blades (32) against the inner (30) and outer (60) ring sectors by means of the heads (38.1) of pins (38).

2. Annular sealing gasket (10, 12, 14) according to claim 1, wherein the pins (38) are mounted floating in the blind holes (60.4) of the outer ring sectors (60).

3. Annular sealing gasket (10, 12, 14) according to any one of claims 1 or 2, wherein each head (38.1) of pin (38) has a spherical cap.

4. Annular sealing gasket (10, 12, 14) according to any one of the preceding claims, wherein the retaining cup (40) is fixed to a radially external flange (60.5) of the annular sealing gasket (10), flange suitable for being fixed to a housing (24).

5. Annular sealing gasket (10, 12, 14) according to any one of the preceding claims, wherein the retaining cup (40) is formed of a hairpin-folded sheet metal having two flat portions (40.1, 40.2) perpendicular to the longitudinal axis (A) and a connecting portion (40.3) describing a cylinder around the longitudinal axis (A); or wherein the retaining cup (40) is formed of a plurality of hairpin-folded sheets, each having two flat portions (40.1, 40.2) perpendicular to the axis longitudinal (A) and a connecting portion (40.3) describing a sector of cylinder around the longitudinal axis (A).

6. Annular sealing gasket (10, 12, 14) according to any one of the preceding claims, wherein blade covers (34) cover at least partially two circumferentially adjacent blades (32).

7. Annular sealing gasket (10, 12, 14) according to any one of the preceding claims, wherein the plurality of blades (32) comprises a blade (32) mounted axially opposite each sector of gasket (32, 60, 62).

8. Annular sealing gasket (10, 12, 14) according to any one of the preceding claims, wherein each inner ring sector (30) comprises an outer lip (30.5) with a front surface (30.52) on which the axial bearing of the blades (32) is made against the inner ring sectors (30).

9. Method of assembling an annular sealing gasket (10, 12, 14) according to any one of the preceding claims, comprising the steps of: providing an assembly comprising a plurality of gasket sectors (30, 60, 62) distributed circumferentially around a longitudinal axis (A), each gasket sector (30, 60, 62) comprising an inner ring sector (30) connected to an outer ring sector (60) by a return member (62); positioning blades (32) in axial support against the inner (30) and outer (60) ring sectors; then positioning a retaining cup (40) applying a force on the blades (32) to maintain contact between the blades (32) and the inner (30) and outer (60) ring sectors.

10. Turbomachine (1) comprising: a high-pressure compressor (4); a combustion chamber (5); a high-pressure turbine (6); a first, a second and a third seal (10, 12, 14); and a cooling air supply circuit (9-20) to the high-pressure turbine (6), the air supply circuit comprising an air inlet (9) downstream of the high-pressure compressor (4), a duct (11) separated from the inlet (9) by the first seal (10), a housing (13) separated from the duct (11) by means of the second sealing gasket (12), an air injector (15) opening into the housing (13), a purge outlet (20) separated from the housing (13) by the third sealing gasket (14), and an air outlet (19) from the housing (13) directing the airflow (18) to the high-pressure turbine (6), at least one of the first, second, and third sealing gaskets (10, 12, 14) conforming to any one of claims 1 to R

11. of O. Turbomachine according to claim 10, further comprising a housing (24), and in which, for the seal or seals according to any one of claims 1 to 8, the retaining cup (40) is fixed to a radially external flange (60.5) of the annular sealing ring (10) fixed to the housing (24), the axial fixing elements (70) passing through the retaining cup (40), the radially external flange (60.5) of the annular sealing ring (10) and a radially internal flange (24.1) of the housing (24).

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