Sealing device and turbomachine comprising same

Abstract

The invention relates to a sealing device (1) comprising: a ring (10) comprising a primary sealing lip (12) having an inner surface (11) and a secondary sealing lip (14) having a radial surface (13); the invention relates to a sealing device (1) comprising a secondary sealing lip (14), a housing (20) comprising a cylindrical portion (22) and a radial portion (24), said radial portion (24) having a contact surface (23), said ring (10) being biased such that the radial surface (13) of the secondary sealing lip (14) abuts against the contact surface (23) of the housing (20), said sealing device (1) having at least one leakage channel (30) extending between the secondary sealing lip (14) and the housing (20).

Description

Technical Field

[0001] The present invention relates to a sealing device and a turbine including the sealing device. More specifically, the sealing device is used to ensure sealing between a shaft and a partition wall, the partition wall being used to separate a first housing and a second housing. Background Art

[0002] In a turbomachine, multiple seals must be ensured: a first housing may be used to contain air, while a second housing may be used to contain air alone or a mixture of air and oil. In particular, the seals may be intended to prevent oil from flowing from one housing to the other, while ensuring that the pressure difference between the first housing and the second housing remains at a desired level. Often, a perfect seal is not possible or even desirable in certain circumstances. The present invention aims to facilitate seal management.

[0003] Document EP 0 387 122 A1 describes a sealing device comprising:

[0004] a ring having a substantially annular shape extending around a rotating shaft extending in a longitudinal direction, the ring comprising a primary sealing lip having an inner surface configured to radially contact an annular surface of the shaft and a secondary sealing lip having a radial surface extending perpendicular to the longitudinal direction; and

[0005] A housing is configured to maintain a seal relative to the partition wall, the housing comprising a cylindrical portion and a radial portion, the cylindrical portion extending around the ring in the longitudinal direction, the radial portion having a contact surface extending perpendicular to the longitudinal direction, the ring being biased so that the radial surface of the secondary sealing lip abuts against the contact surface of the housing. Summary of the invention

[0006] According to the invention, the sealing device has at least one leakage channel which forms a connection between the first housing and the second housing, the at least one leakage channel extending between the secondary sealing lip and a radial surface of the housing.

[0007] Therefore, when a seal designed and developed to ensure high tightness at a specific location performs well, creating a leakage path can effectively adapt it to ensure lower tightness at another location of the turbine. The same reasoning applies to adapting the turbine or other equipment.

[0008] Furthermore, the secondary sealing lip and housing undergo hardly any relative movement, only low-amplitude vibrations, since they are essentially stationary, unlike the shaft, which can rotate around the axis of rotation. As a result, the wear of the sealing lip and housing is low due to the contact between the radial surface and the contact surface. As a result, the leakage path changes only slightly during use.

[0009] According to another feature of the present disclosure, the ring has at least one groove which is formed in the secondary sealing lip and forms at least one leakage channel.

[0010] The secondary sealing lip is usually more wear-resistant than the primary sealing lip. As a result, the leakage path changes less over time.

[0011] In various embodiments of the sealing device according to the present disclosure, one or more of the following arrangements may also be adopted:

[0012] - the ring comprises a plurality of segments, each segment forming a portion of a circle;

[0013] - at least one leakage channel has a depth in the longitudinal direction of 0.1 to 1 mm;

[0014] - The seal has 3 to 15 leakage paths;

[0015] - at least one leakage channel extends perpendicularly to the longitudinal direction;

[0016] - at least one leakage channel has a rectangular cross section;

[0017] - at least one leakage channel has a semicircular cross section;

[0018] - at least one leakage channel has a triangular cross section;

[0019] At least one leakage channel has a corrugated cross section.

[0020] The present invention also relates to a turbine comprising the sealing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features and advantages of the present invention will be apparent from the following detailed description with reference to the accompanying drawings, in which:

[0022] [ Figure 1 ] schematically shows a turbine including a sealing device.

[0023] [ Figure 2 ] Shown in an enlarged scale Figure 1 The area marked II in FIG. 1 is particularly a sealing device according to the first embodiment, which comprises a plurality of circular segments.

[0024] [ Figure 3 ] shows a sealing device according to a first embodiment in a more enlarged scale.

[0025] [ Figure 4 ] shows a perspective view of a circular segment of a sealing device according to a first embodiment.

[0026] [ Figure 5 ]yes Figure 4 The view at the arrow marked V in FIG.

[0027] [ Figure 6 ] indicates that according to Figure 5 A first variation of the first embodiment.

[0028] [ Figure 7 ] indicates that according to Figure 5 A second variation of the first embodiment.

[0029] [ Figure 8 ] indicates that according to Figure 5 A third variation of the first embodiment.

[0030] [ Fig. 9 ] shows a single-piece ring according to a second embodiment of the sealing device. DETAILED DESCRIPTION

[0031] Figure 1 A turbine 50 including the sealing device 1 is shown. Air entering the turbine 50 passes through a fan 62 and is then divided into a primary airflow 52 and a secondary airflow 54 .

[0032] The main airflow 52 passes through a set of compressors in sequence into the combustion chamber 60, and then passes through a set of turbines. In the illustrated embodiment, the compressor group includes a low-pressure compressor 64 and a high-pressure compressor 66, and the turbine group includes a first turbine 82, a second turbine 84, and a third turbine 86. The fan 62 is connected to the third turbine 86 and rotates relative to the stator 90 around the rotation axis 100 through the first short shaft 72. The low-pressure compressor 64 is connected to the second turbine 84 and rotates relative to the stator 90 around the rotation axis through the second short shaft 74. The high-pressure compressor 66 is connected to the first turbine 82 and rotates relative to the stator 90 around the rotation axis 100 through the third short shaft 76.

[0033] The combustion chamber 60 supplies fuel, which is combusted in the primary airflow 52. The combustion gases form the exhaust airflow 56 downstream of the combustion chamber 60. The exhaust airflow 56 passes through the first turbine 82, the second turbine 84, and the third turbine 86. The third turbine 86 includes a plurality of stages, each stage including an inducer and a rotor.

[0034] The sealing device 1 is used to ensure the seal between the first housing 2 and the second housing 4. The partition wall 92 of the stator partitions the first housing 2 and the second housing 4.

[0035] The first short shaft 72 has a cylindrical bearing surface 73. The cylindrical bearing surface 73 has an annular surface 71, the outer side of which is surrounded by the sealing device 1. The sealing device 1 mainly comprises a ring 10 and a housing 20. The housing 20 comprises a cylindrical portion 22 and a radial portion 24. In a variant, the housing 20 can also include an annular spinner connected to the radial portion 24. The cylindrical portion 22 extends around the ring 10 in the longitudinal direction X. Perpendicular to the longitudinal direction X, the cylindrical portion 22 is located between the ring 10 and the partition wall 92. The housing 20 is fixed to the partition wall 92. An O-ring ensures the seal between the cylindrical portion 22 and the partition wall 92. The radial portion 24 has a contact surface 23 extending perpendicularly to the longitudinal direction X.

[0036] The ring 10 is annular with the rotating shaft 100 as the center. The ring 10 includes a main sealing lip 12 and a secondary sealing lip 14. The main sealing lip 12 has an inner surface 11. The inner surface 11 of the sealing lip faces the annular surface 71. The inner surface 11 of the main sealing lip 12 is substantially in contact with the annular surface 71. The secondary sealing lip 14 includes a radial surface 13 extending perpendicular to the longitudinal direction X.

[0037] The ring 10 is held relative to the housing 20 in the longitudinal direction X between the radial portion 24 and the opposite end formed by the locking ring 26, which is fixed in the cylindrical portion 22 by an elastic ring. A compression spring 32 is distributed around the rotating shaft 100 and extends between the locking ring 26 and the groove of the ring 10 in the longitudinal direction X. The compression spring 32 biases the ring 10 in the longitudinal direction X so that the radial surface 13 of the ring 10 abuts against the contact surface 23 of the housing 20.

[0038] Pins may be provided to prevent the ring 10 from rotating relative to the housing 20 about the rotation axis 100 .

[0039] The ring 10 is preferably made of carbon and the housing 20 is preferably made of steel.

[0040] The sealing device 1 also has leakage channels 30, which extend between the ring 10 and the housing 20. The number of leakage channels 30 is preferably between 3 and 15. In the embodiment shown, the sealing device comprises twelve leakage channels. The total cross-sectional area of ​​the leakage channels 30 is preferably between 0.5 square millimeters and 10 square millimeters. The leakage channels 30 preferably extend perpendicularly to the longitudinal direction X and in the radial direction of the rotating shaft 100.

[0041] In the embodiment shown, the leakage channel 30 is formed by grooves 15 in the secondary sealing lip 14. Each groove 15 has a depth p of 0.1 mm to 1 mm in the longitudinal direction X. The maximum axial wear of the secondary sealing lip 14 in the longitudinal direction X can be expected to reach 50 microns. The groove 15 preferably extends over a width l of 0.5 mm to 5 mm. The groove 15 preferably has a rectangular cross section (e.g., 1.5 mm) in a direction perpendicular to the rotation axis 100. Figure 4 and Figure 5 As shown), semicircular cross section (as Figure 6 As shown), triangular cross section (as Figure 7 ) or a wavy cross section (e.g. Figure 8 scallop shape shown).

[0042] exist Figure 4 In the embodiment shown, the ring 10 includes a plurality of segments 16, specifically three segments in the embodiment shown. An annular spring 19 is located in the groove, exerting pressure on the segment 16, causing its inner surface 11 to tend to abut against the annular surface 71 of the first stub shaft 72. Each segment 16 includes a first covering portion 17 and a second covering portion 18 extending at a certain angle at its ends. The first covering portion 17 of the segment cooperates with the second covering portion 18 of the adjacent segment to form a third-level seal. Figure 4 In the embodiment shown, the sealing device 1 is formed by a segmented radial seal. In a variant, the sealing device 1 can in particular be formed by a fragmented seal or an arch-bound segmented radial seal.

[0043] exist Fig. 9 In the second embodiment shown, the ring 10 is a one-piece annular ring, also called a floating ring seal.

[0044] Of course, the present disclosure is not limited to the embodiments described for illustrative, non-limiting purposes.Thus, although not preferred, the grooves 15 may alternatively (or additionally) be formed on the radial surface 13 of the housing 20 .

Claims

1. A sealing device (1), in particular a sealing device for a turbine (50), for ensuring a seal between a first housing (2) and a second housing (4), the sealing device comprising: a ring (10) having a substantially annular shape and extending around a rotation axis (100) extending in a longitudinal direction (X), the ring (10) comprising a primary sealing lip (12) and a secondary sealing lip (14), the primary sealing lip having an inner surface (11) configured to be in radial contact with an annular surface (71) of the shaft (72), and a secondary sealing lip (14) having a radial surface (13) extending perpendicular to the longitudinal direction (X); a housing (20) configured to maintain a seal relative to a partition wall (92), the housing (20) comprising a cylindrical portion (22) and a radial portion (24), the cylindrical portion (22) extending around the ring (10) in a longitudinal direction (X), the radial portion (24) having a contact surface (23) extending perpendicular to the longitudinal direction (X), the ring (10) being biased so that the radial surface (13) of the secondary sealing lip (14) abuts against the contact surface (23) of the housing (20), The sealing device (1) is characterized in that the sealing device (1) has at least one leakage channel (30) which forms a connection between the first shell (2) and the second shell (4), and the at least one leakage channel (30) extends between the secondary sealing lip (14) and the radial surface (13) of the housing (20).

2. The sealing device according to claim 1, characterized in that: The ring (10) has at least one groove (15) which is formed in the secondary sealing lip (14) and forms the at least one leakage channel (30).

3. A sealing device according to any one of the preceding claims, characterized in that The ring (10) comprises a plurality of segments (16), each segment forming a portion of a circle.

4. A sealing device according to any one of the preceding claims, characterised in that The at least one leakage channel (30) has a depth (p) in the longitudinal direction (X) of 0.1 to 1 mm.

5. A sealing device according to any one of the preceding claims, characterised in that The at least one leakage channel (30) extends perpendicularly to the longitudinal direction (X).

6. A sealing device according to any one of the preceding claims, characterised in that The at least one leakage channel (30) has a rectangular cross section.

7. The sealing device according to any one of claims 1 to 5, characterized in that: The at least one leakage channel (30) has a semicircular cross section.

8. The sealing device according to any one of claims 1 to 5, characterized in that: The at least one leakage channel (30) has a triangular cross section.

9. The sealing device according to any one of claims 1 to 5, characterized in that: The at least one leakage channel (30) has a wave-shaped cross section.

10. A turbomachine (50) comprising a sealing device (1) according to any one of claims 1 to 9.

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