(19)
(11)EP 2 834 501 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
02.09.2020 Bulletin 2020/36

(21)Application number: 13813501.7

(22)Date of filing:  28.03.2013
(51)International Patent Classification (IPC): 
F02K 3/072(2006.01)
F01D 15/12(2006.01)
F16J 15/08(2006.01)
F02C 3/067(2006.01)
F02C 7/36(2006.01)
(86)International application number:
PCT/US2013/034304
(87)International publication number:
WO 2014/007891 (09.01.2014 Gazette  2014/02)

(54)

SEAL WITH NON-METALLIC INTERFACE

DICHTUNG MIT EINER NICHTMETALLISCHEN SCHNITTSTELLE

JOINT AVEC INTERFACE NON MÉTALLIQUE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 02.04.2012 US 201213437513

(43)Date of publication of application:
11.02.2015 Bulletin 2015/07

(73)Proprietor: United Technologies Corporation
Farmington, CT 06032 (US)

(72)Inventors:
  • BURD, Steven W.
    Cheshire, Connecticut 06410-0312 (US)
  • BURSEY, Roger W.
    Jupiter, Florida 33458 (US)
  • MARTINEZ, Gonzalo F.
    Stuart, Florida 34997 (US)
  • HARRIS-MILLER, Meggan H.
    Colchester, Connecticut 06415 (US)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
FR-A1- 2 789 144
US-A- 4 022 948
US-A- 4 645 217
US-A- 5 222 692
US-A1- 2006 012 133
US-A1- 2006 197 287
US-A- 4 022 948
US-A- 4 645 217
US-A- 5 222 692
US-A- 5 657 998
US-A1- 2006 197 287
US-B1- 6 415 599
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND



    [0001] This invention generally relates to a seal between a fixed member and a movable member. More particularly, this invention relates to a finger seal between relatively moveable ducts.

    [0002] A gas turbine engine typically includes an exhaust duct for directing exhaust gases. Many exhaust duct assemblies include a movable portion for selectively directing the exhaust gases. Such exhaust duct assemblies includes a fixed portion and a movable portion. A seal is required between the fixed and movable portions to prevent intrusion of exhaust gases through the exhaust nozzle assembly at the interface between the fixed and movable portions.

    [0003] A seal may be provided by a plurality of fingers that are defined by a corresponding plurality of slots. The slots and finger configuration provide for flexing and expansion of the movable member relative to the fixed portion. Known seals utilize staggered overlapping configurations to prevent leakage.

    [0004] Finger seals are often fabricated in sheet metal and are comprised of machined or photo-etched finger shapes attached to or integral to thin metal laminate rings, stacking the laminates so that the fingers of one laminate overlap the fingers of the adjacent laminates. The stack is held together with mechanical or bonding means including rivets and fasteners.

    [0005] A finger seal consists of long, pointed "fingers" angled in the direction of the sealing surface or the rotation in applications involving enclosed shafts. Gaps between the fingers allow each finger to flex in response to thermal, dynamic and/or vibratory loads between the two components. Prior art in this area including US 4022948, US 5222692, US 2006/0197287 and FR 2789144.

    [0006] Wear can occur between the fingers and lands that interact with the fingers.

    SUMMARY



    [0007] According to an aspect of the invention, an assembly is claimed in claim 1.

    [0008] In a non-limited embodiment of any of the foregoing embodiments, the plurality of fingers is metallic and the seal is polytetrafluoroethylene-based.

    [0009] In a further non-limited embodiment of any of the foregoing embodiments, the seal is comprised of any of carbon, silicone, ceramic or composite-based materials.

    [0010] In a further non-limited embodiment of any of the foregoing embodiments, the plurality of fingers is metallic.

    [0011] In a further non-limited embodiment of any of the foregoing embodiments, the seal further comprises a second plurality of fingers disposed over the first plurality of fingers.

    [0012] In a further non-limited embodiment of any of the foregoing embodiments, the second plurality of fingers covers a gap between adjacent fingers of the first plurality of fingers.

    [0013] In a further non-limited embodiment of any of the foregoing embodiments, one of the first plurality of fingers has an elbow and an extension extending upwardly at an angle from the elbow.

    [0014] In a further non-limited embodiment of any of the foregoing embodiments, the angle is approximately 135 degrees ± 15 degrees.

    [0015] In a further non-limited embodiment of any of the foregoing embodiments, the extension has a radially outer non-flat surface.

    [0016] In a further non-limited embodiment of any of the foregoing embodiments, the seal further comprises a second plurality of fingers overlapping the first plurality of fingers wherein one of the second plurality of fingers has a radially inner surface mating with the radially outer non-flat surface.

    [0017] In a further non-limited embodiment of any of the foregoing embodiments, the extension terminates in a curvilinear shape.

    [0018] In a further non-limited embodiment of any of the foregoing embodiments, the seal further comprises a second plurality of fingers overlapping the first plurality of fingers wherein one of the second plurality of fingers terminates in a shape that mates with a portion of the curvilinear shape.

    [0019] According to a further embodiment disclosed herein, a gas turbine engine seal is provided as claimed in claim 13.

    [0020] In a further non-limited embodiment of any of the foregoing embodiments, the plurality of fingers is metallic and the seal is polytetrafluoroethylene-based.

    [0021] In a further non-limited embodiment of any of the foregoing embodiments, the seal is comprised of any of carbon, silicone, ceramic or composite-based materials.

    [0022] In a further non-limited embodiment of any of the foregoing embodiments, one of the first plurality of fingers has an elbow and an extension extending upwardly at an angle from the elbow.

    [0023] In a further non-limited embodiment of any of the foregoing embodiments, the extension has a radially outer non-flat surface.

    [0024] In a further non-limited embodiment of any of the foregoing embodiments, the extension terminates in a curvilinear shape.

    [0025] In a further non-limited embodiment of any of the foregoing embodiments, the second surface is a polytetrafluoroethylene-based fabric.

    [0026] In a further non-limited embodiment of any of the foregoing embodiments, the second surface is a polytetrafluoroethylene-based fabric that is bonded to one of the one of the plurality of fingers or the seal land in register with an elbow of the plurality of fingers.

    DESCRIPTION OF THE DRAWINGS



    [0027] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows:

    Figure 1 is a schematic depiction of a jet engine in which finger seals are disclosed.

    Figure 2 is a respective, cross-sectional view of the seal structure of Figure 1.

    Figure 3 is a cross-sectional view of the finger seal of Figure 2.

    Figure 4 is a perspective view of a portion of a seal land of Figure 2.

    Figure 5 is a cross-sectional view of the finger seal as shown in Figure 3.


    DETAILED DESCRIPTION



    [0028] Referring to FIG. 1, a machine, such as a gas turbine engine assembly 10, includes a compressor 12 for compressing incoming air. Compressed air is mixed with fuel in a combustor 14 and ignited to generate an axial flow of hot exhaust gases 24. The hot exhaust gases drive a turbine 16 that in turn drives the compressor 12. An exhaust duct assembly 18 directs the outgoing exhaust gases 24 from the gas turbine engine assembly 10. The exhaust duct assembly 18 includes a fixed part 22 and a movable part 20 for selectively directing exhaust gases 24. The interface 25 between the fixed part 22 and movable part 20 includes a seal 26, as will be discussed infra, for substantially preventing leakage of exhaust gases radially from the exhaust duct assembly 18. One of ordinary skill in the art will recognize from the teachings herein that the seal 26 as described herein may be used in other areas of the gas turbine engine assembly 10 and other types of machinery where a finger seal 26 might be used.

    [0029] The seal 26 includes a plurality of flexible members 34 or fingers that extend from the fixed part 22 towards and in contact with the moveable part 20. The flexible members 34 provide for expansion and contraction along with creating flexibility in the region of contact between a seal land 36 on the moveable part and the seal 26. As appreciated, although the seal 26 is shown mounted to the fixed part 22, it may also be fixed to the movable part 20 and contact a seal land on the fixed part 22.

    [0030] The "finger seal" 26 provides air-to-air sealing for secondary flow control and gas path sealing in gas turbine engines. Although this seal 26 was developed for gas turbine engine assemblies 10, it can be used in any machinery in which a relatively higher pressure air cavity is to be sealed from a relatively lower pressure air cavity, for both static and rotating applications, and/or in applications in which adjacent components require a flexible interface due to displacement, vibration, or relative thermal growth. Long-life, low-leakage finger seal provide many benefits for propulsion gas turbine engines, including cost (relative to alternatives), design flexibility and secondary flow management.

    [0031] It has been discovered that finger seals of the prior art (not shown) may wear into a sealing surface (as will be discussed infra), the sealing surface may wear into the finger seals or the both surfaces wear into each other during use. The wear can lead to premature seal durability issues, reduce the longevity and effectiveness or both components and be detrimental to the application in which the seals are used. To improve the wear characteristics, seal and sealing surfaces are often produced with surface coatings or hard coats. Such coating applications may be beneficial but do not mitigate the problematic wear and still involve metal-to-metal interfaces.

    [0032] Referring now to Figure 2, an extension 30 attaches to turbine casing 50 (e.g. the stationary portion 22), has a flat circumferential section 35, a tapered adjusting section 40, and a first clamping area 45. The adjusting section 40 is used to place the finger seals 26 at a proper position relative to an exhaust nozzle or duct 18 that may have varying diameters on different engine platforms (not shown). As shown, the adjusting section 40 tapers radially inwardly from the casing 50 to the duct 18, however it is conceivable it would taper radially outwardly in other cases. The first clamping area 45 is roughly in parallel to the casing 50.

    [0033] The casing 50 has a conduit portion 55 that is defined by a loop 60 in the conduit portion 55. The conduit portion 55 also has a portion 65 mating with the adjusting section 40. The conduit portion 55 continues to a second clamp area 75 that is parallel to and in register with the first clamping area 45. The two clamp areas can be clamped together by rivets 70

    [0034] Fingers 80 form a first layer 85, the first layer having a plurality of gaps 90, and fingers 100 form a second layer 95, the second layer having a plurality of gaps 97 between each finger 100. The fingers 80 of the first layer 85 and fingers 100 in the second layer 95 register with each other so that the first layer gaps 90 do not align with the second layer gaps 100. By staggering the gaps 90, 100 leakage of air between the first and second layers 85, 95 is minimized. As is known in the art, a metal or fabric (not shown) may be disposed between the fingers to further minimize air leakage therebetween. The first layer 85 of fingers 80 define an elbow 101 for contacting with a seal 160 as will be discuss infra.

    [0035] Each finger 80 in the first layer 85 has an irregularly-shaped, radially outwardly extending portion 110 (e.g., or non-flat or ridged shape) extending from the finger 100 at an angle of about 135° + 15° and terminates in a first ovoid or curvilinear shape 111. Each finger 100 in the second layer 95 has a plurality of non-flat surfaces or ridges 115 on a radially-inward portion thereof and terminates at a second ovoid or curvilinear section 120. The second layer 95 mates with the first layer 85 such that the non-flat surface 110 mates with the non-flat surface 115. The first ovoid or curvilinear section 111 snaps on or otherwise mates with the second ovoid or curvilinear section 120. The non-flat surfaces 110, 115, and the first and second curvilinear surfaces 111, 120 essentially form a labyrinth seal 140 to further minimize leakage through the first layer 85 and the second layer 95.

    [0036] Referring to Figure 3, a seal land 36 that is essentially an angle iron-shaped body 150 attaches to the exhaust duct 18 (see Fig. 2). The seal land 36 has a relatively flat circumferential surface 155 that is joined to a vertical attaching surface 157 that attaches conventionally to the exhaust duct 18. A seal 160 may be segmented (see dotted lines 165) or may be one piece. The seal may be mechanically attached to the seal land circumferential surface 155 or glued thereto. If the seal 160 is segmented, differences in temperature between an interior of the duct 151 and the exterior thereof may be absorbed by the gaps between each segment. The elbows 101 of the first layer 85 fit against the seal 160 (see Fig. 2). The seal 160 may be made of a polytetrafluoroethylene-based or a thermoplastic polymer and may also be a polytetrafluoroethylene-based fabric liner 160. As one of ordinary skill in the art will appreciate from the teachings herein, the fabric liner 161 (See also Figure 4) may also be bonded to the fingers and the seal 160 may be metallic. The fabric liner is in register with the elbow 101.

    [0037] The first layer of finger seals 85 and the second layer of the finger seals 95 are flexible and may also be made of a polytetrafluoroethylene-based or a thermoplastic polymer as well as metal. The metallic finger seal element interfaces with the non-metallic pads to provide a metallic to non-metallic wear interface to minimize premature wear of the seal land 36.

    [0038] By using a slippery material relative to metal, it is less probable that the elbows 101 will seat themselves in the seal 160 thereby minimizing premature failure of the seal.

    [0039] A further embodiment show the seal to be comprised as comprised of carbon, silicone, ceramic or composite-based materials because of their wear and lubricity characteristics. According to a further embodiment finger seals may be comprised of ceramic or composite-based materials.

    [0040] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the scope of the appended claims.


    Claims

    1. An assembly (18) comprising a fixed part (22) and a movable part (26), said fixed and movable parts (22, 20) configured for relative motion therebetween, said assembly comprising a seal assembly (26), the seal assembly (26) comprising:

    a first plurality of fingers (80) each of which being attached to and disposed about one of said fixed part (22) and said movable part (20),

    a seal land (36) attached to the other of said fixed part (22) and said movable part (20), and

    a seal (160) attached to said seal land (36) and in contact with said plurality of fingers (80) wherein a first surface of one of said plurality of fingers (80) and said seal (160) is metallic and a second surface of another of said seal land (36) or said plurality of fingers (80) is non-metallic.


     
    2. The assembly of claim 1 wherein said second surface is a polytetrafluoroethylene-based fabric.
     
    3. The assembly of claim 1 or 2 wherein said seal (160) is comprised of any of carbon, silicone, ceramic or composite-based materials.
     
    4. The assembly of claim 1, 2 or 3 wherein each of said plurality of fingers (80) is metallic.
     
    5. The assembly of any preceding claim further comprising a second plurality of fingers (100) disposed over said first plurality of fingers (80).
     
    6. The assembly of claim 5 wherein said second plurality of fingers (100) covers a gap (90) between adjacent fingers of said first plurality of fingers (80).
     
    7. The assembly of any preceding claim wherein one of said first plurality of fingers (80) has an elbow (101) and an extension extending upwardly at an angle from said elbow (101).
     
    8. The assembly of claim 7 wherein said angle is approximately 135 degrees + 15 degrees.
     
    9. The assembly of claim 7 or 8 wherein said extension has a radially outer non-flat surface.
     
    10. The assembly of claim 7, 8 or 9 wherein said extension terminates in a curvilinear shape.
     
    11. The assembly of claim 10 further comprising a second plurality of fingers (100) overlapping said first plurality of fingers (80) wherein one of said second plurality of fingers (100) terminates in a shape that mates with a portion of said curvilinear shape.
     
    12. The assembly of any preceding claim further comprising a second plurality of fingers (100) overlapping said first plurality of fingers (80) wherein one of said second plurality of fingers (100) has a radially inner surface mating with said radially outer non-flat surface.
     
    13. A gas turbine engine seal comprising an assembly in accordance with any preceding claim.
     
    14. The gas turbine engine seal of claim 13 wherein said seal is polytetrafluoroethylene-based.
     
    15. The gas turbine engine seal of claim 13 or 14 wherein said second surface is a polytetrafluoroethylene-based fabric that is bonded to one of said one of said plurality of fingers (80) or said seal land (36) in register with an elbow (101) of said plurality of fingers (88).
     


    Ansprüche

    1. Baugruppe (18), umfassend ein festes Teil (22) und ein bewegliches Teil (26), wobei das feste Teil und das bewegliche Teil (22, 20) für eine relative Bewegung dazwischen ausgelegt sind, wobei die Baugruppe eine Abdichtungsanordnung (26) umfasst, wobei die Abdichtungsanordnung (26) umfasst:

    eine erste Vielzahl von Fingern (80), wovon jeder an einem von dem festen Teil (22) und dem beweglichen Teil (20) angebracht und darum angeordnet ist,

    eine Dichtfläche (36), die an dem anderen von dem festen Teil (22) und dem beweglichen Teil (20) angebracht ist, und

    eine Dichtung (160), die an der Dichtfläche (36) angebracht ist und mit der Vielzahl von Fingern (80) in Berührung steht, wobei eine erste Fläche von einer von der Vielzahl von Fingern (80) und der Dichtung (160) metallisch ist und eine zweite Fläche einer anderen von der Dichtfläche (36) oder der Vielzahl von Fingern (80) nicht metallisch ist.


     
    2. Baugruppe nach Anspruch 1, wobei es sich bei der zweiten Fläche um einen Stoff auf Polytetrafluorethylenbasis handelt.
     
    3. Baugruppe nach Anspruch 1 oder 2, wobei die Dichtung (160) aus einem beliebigen von Kohlenstoff, Silikon, Keramik oder auf Verbundstoff basierenden Materialien besteht.
     
    4. Baugruppe nach Anspruch 1, 2 oder 3, wobei jeder von der Vielzahl von Fingern (80) metallisch ist.
     
    5. Baugruppe nach einem der vorhergehenden Ansprüche, weiterhin umfassend eine zweite Vielzahl von Fingern (100), die über der ersten Vielzahl von Fingern (80) angeordnet ist.
     
    6. Baugruppe nach Anspruch 5, wobei die zweite Vielzahl von Fingern (100) einen Spalt (90) zwischen benachbarten Fingern der ersten Vielzahl von Fingern (80) abdeckt.
     
    7. Baugruppe nach einem der vorhergehenden Ansprüche, wobei einer von der ersten Vielzahl von Fingern (80) einen Bogen (101) und ein Ansatzstück aufweist, das sich in einem Winkel von dem Bogen (101) nach oben erstreckt.
     
    8. Baugruppe nach Anspruch 7, wobei der Winkel etwa 135 Grad ± 15 Grad beträgt.
     
    9. Baugruppe nach Anspruch 7 oder 8, wobei das Ansatzstück eine radial außenliegende nicht flache Fläche aufweist.
     
    10. Baugruppe nach Anspruch 7, 8 oder 9, wobei das Ansatzstück in einer gekrümmten Form ausläuft.
     
    11. Baugruppe nach Anspruch 10, weiterhin umfassend eine zweite Vielzahl von Fingern (100), die die erste Vielzahl von Fingern (80) überlappt, wobei eine von der zweiten Vielzahl von Fingern (100) in einer Form ausläuft, die mit einem Abschnitt der gekrümmten Form zusammenpasst.
     
    12. Baugruppe nach einem der vorhergehenden Ansprüche, weiterhin umfassend eine zweite Vielzahl von Fingern (100), die die erste Vielzahl von Fingern (80) überlappt, wobei eine von der zweiten Vielzahl von Fingern (100) eine radial innenliegende Fläche aufweist, die mit der radial außenliegenden nicht flachen Fläche zusammenpasst.
     
    13. Gasturbinentriebwerksdichtung, umfassend eine Baugruppe nach einem vorhergehenden Anspruch.
     
    14. Gasturbinentriebwerksdichtung nach Anspruch 13, wobei die Dichtung auf Polytetrafluorethylen basiert.
     
    15. Gasturbinentriebwerksdichtung nach Anspruch 13 oder 14, wobei die zweite Fläche ein Stoff auf Polytetrafluorethylenbasis ist, der mit einer von der Vielzahl von Fingern (80) oder der Dichtfläche (36) in Ausrichtung mit einem Bogen (101) von der Vielzahl von Fingern (88) verklebt ist.
     


    Revendications

    1. Ensemble (18) comprenant une partie fixe (22) et une partie mobile (26), lesdites parties fixe et mobile (22, 20) étant configurées pour un mouvement relatif entre elles, ledit ensemble comprenant un ensemble de joint (26), l'ensemble de joint (26) comprenant :

    une première pluralité de doigts (80) dont chacun est fixé à et disposé autour de l'une de ladite partie fixe (22) et de ladite partie mobile (20),

    une zone de joint (36) fixée à l'autre de ladite partie fixe (22) et de ladite partie mobile (20), et

    un joint (160) fixé à ladite zone de joint (36) et en contact avec ladite pluralité de doigts (80) dans lequel une première surface de l'un de ladite pluralité de doigts (80) et dudit joint (160) est métallique et une seconde surface d'une autre de ladite zone de joint (36) ou de ladite pluralité de doigts (80) est non métallique.


     
    2. Ensemble selon la revendication 1, dans lequel ladite seconde surface est un tissu à base de polytétrafluoroéthylène.
     
    3. Ensemble selon la revendication 1 ou 2, dans lequel ledit joint (160) est composé de l'un quelconque parmi les matériaux à base de carbone, de silicone, de céramique ou de composite.
     
    4. Ensemble selon la revendication 1, 2 ou 3, dans lequel chacun de ladite pluralité de doigts (80) est métallique.
     
    5. Ensemble selon une quelconque revendication précédente, comprenant en outre une seconde pluralité de doigts (100) disposée sur ladite première pluralité de doigts (80).
     
    6. Ensemble selon la revendication 5, dans lequel ladite seconde pluralité de doigts (100) couvre un espace (90) entre les doigts adjacents de ladite première pluralité de doigts (80).
     
    7. Ensemble selon une quelconque revendication précédente, dans lequel l'un de ladite première pluralité de doigts (80) a un coude (101) et une extension s'étendant vers le haut selon un angle dudit coude (101).
     
    8. Ensemble selon la revendication 7, dans lequel ledit angle est d'environ 135 degrés ± 15 degrés.
     
    9. Ensemble selon la revendication 7 ou 8, dans lequel ladite extension a une surface non plate radialement extérieure.
     
    10. Ensemble selon la revendication 7, 8 ou 9, dans lequel ladite extension se termine par une forme curviligne.
     
    11. Ensemble selon la revendication 10, comprenant en outre une seconde pluralité de doigts (100) chevauchant ladite première pluralité de doigts (80), dans lequel l'un de ladite seconde pluralité de doigts (100) se termine par une forme qui s'accouple avec une partie de ladite forme curviligne.
     
    12. Ensemble selon une quelconque revendication précédente, comprenant en outre une seconde pluralité de doigts (100) chevauchant ladite première pluralité de doigts (80), dans lequel l'un de ladite seconde pluralité de doigts (100) a une surface radialement intérieure s'accouplant avec ladite surface non plate radialement extérieure.
     
    13. Joint de moteur de turbine à gaz comprenant un ensemble selon une quelconque revendication précédente.
     
    14. Joint de moteur à turbine à gaz selon la revendication 13, dans lequel ledit joint est à base de polytétrafluoroéthylène.
     
    15. Joint de moteur à turbine à gaz selon la revendication 13 ou 14, dans lequel ladite seconde surface est un tissu à base de polytétrafluoroéthylène qui est lié à l'une de ladite une de ladite pluralité de doigts (80) ou de ladite zone de joint (36) en alignement avec un coude (101) de ladite pluralité de doigts (88) .
     




    Drawing











    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description