Note: Within nine months from the publication of the mention of the grant of the European patent, any person may givenotice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed ina 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).

Printed by Jouve, 75001 PARIS (FR)

Europisches Patentamt

European Patent Office

Office europen des brevets

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(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mentionof the grant of the patent:25.02.2004 Bulletin 2004/09

(21) Application number: 97304672.5

(22) Date of filing: 27.06.1997

(51) Int Cl.7: F01D 11/00, F01D 5/26

(54) Turbine blade damper and seal

Dmpfungselement und Dichtung fr Turbinenschaufeln

Elment amortisseur et garniture dtanchit pour aubes de turbine

(84) Designated Contracting States:DE FR GB

(30) Priority: 27.06.1996 US 671462

(43) Date of publication of application:07.01.1998 Bulletin 1998/02

(60) Divisional application:02026363.8 / 1 291 492

(73) Proprietor: UNITED TECHNOLOGIESCORPORATIONHartford, CT 06101 (US)

(72) Inventors: Gonsor, Michael

Hebron, Connecticut 06248 (US)

Kelly III, Sanford E.Vernon, Connecticut 06066 (US)

Houston, David P.Glastonbury, Connecticut 06033 (US)

(74) Representative: Leckey, David HerbertFrank B. Dehn & Co.,European Patent Attorneys,179 Queen Victoria StreetLondon EC4V 4EL (GB)

(56) References cited:EP-A- 0 062 558 WO-A-94/12774WO-A-95/27841 GB-A- 2 111 130US-A- 4 101 245 US-A- 5 313 786US-A- 5 415 526

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Description

[0001] The invention relates to gas turbine enginesand more particularly to damper and seal configurationsfor turbine rotors.[0002] A typical gas turbine engine has an annular ax-ially extending flow path for conducting working fluid se-quentially through a compressor section, a combustionsection, and a turbine section. The compressor sectionincludes a plurality of rotating blades which add energyto the working fluid. The working fluid exits the compres-sor section and enters the combustion section. Fuel ismixed with the compressed working fluid and the mix-ture is ignited to add more energy to the working fluid.The resulting products of combustion are then expand-ed through the turbine section. The turbine section in-cludes another plurality of rotating blades which extractenergy from the expanding fluid. A portion of this ex-tracted energy is transferred back to the compressorsection via a rotor shaft interconnecting the compressorsection and turbine section. The remainder of the ener-gy extracted may be used for other functions.[0003] Each of the plurality of rotating blades in theturbine section has a platform. A blade root extends fromone surface of the platform, and a blade airfoil projectsfrom an opposing surface. The airfoil, which may beshrouded or unshrouded, extracts the kinetic energyfrom the expanding working fluid. The plurality of rotorblades are distributed among one or more rotating tur-bine rotors. A turbine rotor has a disk having a centerlineand a series of slots in its outer perimeter. Each slot re-ceives a blade root, thereby retaining the blade to thedisk. So installed, the blade extends radially from thedisk, with the root radially inward and the airfoil radiallyoutward.[0004] Adjacent blade platforms are separated by anaxially extending gap, which keeps the blades platformsfrom contacting and damaging each other.[0005] As the airfoils extract energy from the expand-ing working fluid, the working fluid exerts a loading forceon the airfoils. Variations in the loading force cause theblades to deflect and vibrate. This vibration has a broadspectrum of frequency components, with greatest am-plitude at the natural resonant frequency of the blades.When the airfoils are unshrouded, the vibration is pri-marily tangential to the direction of rotation, i.e. the cir-cumferential direction. There is also a secondary vibra-tion component in the direction of fluid flow, i.e. the axialdirection. If undamped, the deflection of the vibratingblades can reach extreme limits, potentially causing theairfoil to break.[0006] The susceptibility of the turbine to blade vibra-tion failure depends in part on effective damping. Adamper is generally employed to reduce such vibration.The damper is a rigid element which is positioned tospan the gap between blades and contact the radiallyinner surfaces of adjacent blade platforms. The damperreduces blade to blade vibration which consequently re-

duces individual blade vibration. The shape, weight, andstiffness of the damper is selected to best provide thedesired vibration damping friction force. For maximumeffectiveness, the damper is generally elongated in theaxial direction.[0007] The friction force provided by the damper issplit between the adjacent blades. Generally, an evensplit is sought, i.e. fifty percent to one blade and fifty per-cent to the other blade. However, the shape and contourof the radially inner surfaces of the blade platforms, inconjunction with the other damper selection criteriamentioned above, may not allow a damper which pro-vides the desired damping profile. In such instances,damping effectiveness may be reduced, resulting in low-er blade reliability. Therefore, a damper which offersmore flexibility in vibration damping to produce the de-sired damping profile is sought.[0008] Aside from vibration failure, there further existsthe possibility of turbine failure due to the potential leak-age of the working fluid into the gap between adjacentblade platforms. Once in the gap, the working fluid canthen leak into the area beneath the radially inner surfaceof the platform. Since the temperature of the workingfluid in the turbine is generally higher than that whichcomponents beneath the platform can safely withstand,leakage raises the temperature of these componentsand generally results in lower turbine reliability. Further-more, since the working fluid may contain contaminants,leakage can transport contaminants beneath the plat-form, further reducing the reliability of the turbine. In ad-dition, the leaking working fluid circumvents the airfoils,thus reducing the amount of energy delivered to the air-foils and reducing the efficiency of the turbine.[0009] A seal is generally employed to reduce leak-age The seal is a flexible element, typically made of thinsheet metal, which is positioned across the gap, be-neath and in proximity to the radially inner surfaces ofadjacent blade platforms. The seal typically has a por-tion which generally conforms with that of the surfacewith which it is to seal.[0010] The seal typically requires radial support fromthe damper. One example of such a damper and sealconfiguration is disclosed in U.S. Patent No. 5,460,489.However, if the damper does not provide sufficient radialsupport, e.g. along a sufficient portion of the axial lengthof the seal, then the seal may be susceptible to distortionupon turbine rotation due to radial centrifugal forces.The constraints on the design of the damper, describedabove, frequently limit the radial support that the dampercan provide to the seal. Should the seal experience suchdistortion, its proximal relation to the surfaces with whichit seals may be undesirably altered, and consequently,sealing effectiveness may be reduced. Therefore adamper and seal configuration which offers more designflexibility in order to obtain greater radial support for theseal is also sought.[0011] Generally, the seal is only loosely captured inthe axial direction by the structure beneath the platform.

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However, to preserve optimum proximal relation of theseal to the surfaces with which it seals, the seal mustbe maintained in the proper axial position relative to theradial inner surface of the adjacent blade platforms. Ifthe seal is not maintained in the proper axial position,the effectiveness of the seal in reducing leakage maybe decreased. A seal which can be maintained in properaxial position is therefore sought.[0012] Finally, in order to provide effective dampingand sealing, the damper and seal must be installed inproper relative position with respect to each other. How-ever, in prior art arrangements, the damper and sealmay fit in the turbine assembly even though installed im-properly, and consequently, in current turbine configu-rations there is a potential for misassembly. This poten-tial is increased by the fact that some configurationshave the damper disposed between the platform and theseal, while others have the seal disposed between theplatform and the damper. As a result, the damper andseal are occasionally installed improperly, thereby re-ducing the effectiveness of both the damper and theseal. It is therefore desirable to provide a damper andseal configuration which prevents the installation of thedamper and seal in improper orientation with respect toeach other.[0013] According to a first aspect of the present inven-tion, there is provided a rigid vibration damper for usewith a turbine rotor blade and a seal in a gas turbineengine, the turbine rotor blade having an airfoil portion,a platform, a neck, and a root, the blade platforms eachhaving a radially outer surface, and a radially inner sur-face connected by the blade neck to the blade root, theradially inner surface having a damping portion, and theseal having at least one sealing portion extending froma supported portion, said at least one sealing portionadapted, in use, to provide sealing in combination withthe sealing portion of adjacent blade platform radiallyinner surfaces, wherein the rigid damper comprises:

a main body having a damping surface adapted, inuse, to contact the damping portion of adjacent plat-form radially inner surfaces and to provide a frictionforce on the damping portions;

and wherein the main body also has a support sur-face for supporting the supported portion of the seal inuse, by means of which the damper is supported, thesupport surface being larger than the damping surface,and at least one end axially extended from the mainbody adapted, so as in use, to be spaced at a clearancefrom the adjacent platform radially inner surfaces.[0014] A damper having at least one extended endprovides greater design flexibility for producing the de-sired damping profile. Because of the clearance be-tween the extended end and the radially inner surfaceof the platform, the extended end can extend over areasof the inner surface that the main body should not con-tact, due to the risk of interfering with the desired contact

area between the main body and the inner surface.Since the weight of the damper includes the weight ofthe extended end, the addition of the extended end al-lows greater flexibility in distributing the weight of thedamper. Consequently, there is greater flexibility for pro-ducing the desired damping profile, including but not lim-ited to, a more even distribution of the damper frictionforce between the two adjacent blades, thereby improv-ing damping effectiveness. The one or more extendedends are preferably a pair of tapered axial extensions.[0015] The present invention also extends to a damp-er and seal combination. A damper and seal configura-tion having a damper with at least one extended endprovides greater damper and seal design flexibility andallows for additional (enhanced) radial support for theseal. This additional radial support reduces the unde-sired distortion in the seal under centrifugal forces, andconsequently results in greater sealing effectivenessthan that which can be achieved without at least oneextended end.[0016] A preferred embodiment of the invention willnow be described by way of example only and with ref-erence to the accompanying drawings, in which:

FIG. 1 is a perspective view of a turbine rotor bladewith a damper and seal configuration of the presentinvention;FIG. 2 is a side view of the rotor blade and damperand seal configuration of FIG 1;FIG. 3 is a top view of the damper of FIG. 1;FIG. 4 is a perspective view of a concave side ofthe damper of FIG. 1;FIG. 5 is a top view of the seal of FIG. 1;FIG. 6 is a perspective view of the side of the sealof FIG. 1; andFIG. 7 is a perspective view of the rotor blade,damper, and seal of FIG. 1 shown separated priorto installation.

[0017] The damper and seal configuration of thepresent invention is disclosed with respect to a preferredembodiment for use with a second stage high pressureturbine rotor blade of the type illustrated in FIG. 1. Asshould be understood by those skilled in the art, thedrawings are meant to be illustrative only and are notintended to portray exact structural dimensions.[0018] Referring to FIG. 1, a turbine rotor blade 10 hasa upstream side 12, a downstream side 14, a concave(pressure) side 16, and a convex (suction) side 18. Therotor blade 10 has an airfoil 22, which receives kineticenergy from a gas flow 24. The airfoil 22, which may beshrouded or unshrouded, is disposed on a radially outersurface 26 of a platform 28. The platform 28 further com-prises a radially inner surface 30, a leading edge 32 anda trailing edge 34. A pair of platform supports 36,38 pro-vide structural support for the platform 28 to reduce dis-tortion in the platform. In the preferred embodiment, therotor blade 10 is fabricated as a single integral unit by

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casting; however, any other suitable means known tothose skilled in the art may also be used.[0019] The rotor blade 10 further comprises a neck 65of reduced thickness, and a root 66. The neck 65 is thetransition between the platform 28 and the root 66. Theroot 66 is inserted into a turbine rotor central disk (notshown) to attach the rotor blade to the disk. In the illus-trated embodiment, the root 66 has a fir tree design,however, any suitable means for attaching the blade tothe disk may be used. The neck 65 has a pair of protru-sions 64 (only one shown) which are described andshown in further detail hereinbelow.[0020] While not shown, the rotor blade 10 is one ofa plurality of such blades attached to a rotor disk havinga centerline (longitudinal axis) (not shown). The blade10 extends radially from the disk, with the root 66 radiallyinward and the airfoil 22 radially outward. Adjacentblade platforms are separated by an axially extendinggap, which keeps the blade platforms from contactingand damaging each other. The width of this gap shouldbe large enough to accommodate the tolerances in thephysical dimensions of the platforms including thermalexpansion. In the best mode embodiment, the width ofthe gap is on the order of about 0.04 inches (1 mm);however any suitable gap width may be used.[0021] Located beneath the radially inner surface 30of the platform 28 is a damper 40 and seal 42 configu-ration. The damper 40 is a rigid element adapted to re-duce blade-to-blade vibration which consequently re-duces individual blade vibration. The damper 40 alsoprovides support for the seal 42. The damper 40 is po-sitioned to span the gap between the platform 28 andthe adjacent blade platform (not shown) and to contactthe radially inner surfaces of the platforms. The shape,weight, and stiffness of the damper is selected to bestprovide the desired friction force to the platforms forsuch damping. For maximum effectiveness, the damperis generally elongated in the direction of the disk cen-terline, i.e. the axial direction.[0022] The seal 42 is a flexible element, typicallymade of thin sheet metal, adapted to reduce leakage.The seal is positioned radially inwardly of the damper,across the gap between the platform 28 and the adja-cent blade platform (not shown), beneath and in prox-imity to the radially inner surfaces of the platforms. Theshape of the seal generally conforms with that of the por-tion of the surface with which it is to seal. As illustrated,the damper 40 and seal 42 are radially supported by thepair of protrusions 64 on the blade 10 neck 65, however,any other suitable means known to those skilled in theart for holding the damper 40 and seal 42 in place mayalso be used. The damper 40 and seal 42 are describedin further detail hereinbelow.[0023] Referring now to FIG. 2, in a side view of thepressure side of the rotor blade 10, and damper 40 andseal 42 configuration, the radially inner surface 30 of theblade platform 28 has a damping portion 44, a transitionportion 46 and a sealing portion 48. As shown, the

damping portion 44 of the platform radially inner surface30 has a substantially planar contour, however, thedamping portion 44 may have any suitable contourknown to those skilled in the art, including but not limitedto a large radius, arcuate surface. The transition portion46 of the platform radially inner surface 30 is locatedbetween the damping portion 44 and the sealing portion48, where the radially inner surface 30 contour changesfrom that of the damping portion 44 to that of the sealingportion 48. Largely for this reason, no damping or seal-ing occurs in the transition portion 46. The transition por-tion 46 comprises upstream and downstream fillet ru-nouts, shown as corners, having substantially arcuatecontour, and providing a roughly ninety degree bendwith a radius; however, the transition portion 46 mayhave any suitable contour known to those skilled in theart. The sealing portion 48 of the platform radially innersurface 30 is located where sealing against leakage issought. The pressure on the radially outer surface 28 ofthe platform 28 is generally greater than that on the ra-dially inner surface 30. For the blade 10, the magnitudeof this pressure differential is comparatively high in theproximity of the platform supports. Consequently, asshown, the sealing portion 48 is located on the insidesurfaces of the platform supports 36,38; however, thesealing surface 48 may have any suitable location andcontour known to those skilled in the art.[0024] The damper 40 comprises a main body 50 anda pair of extended ends 52. The main body 50 has adamping surface 54 in contact with the damping portion44 of the platform radially inner surface 30. The area ofthe damping surface 52 in combination with the weightof the damper 40, provide the friction force necessaryto damp vibration. The blade vibration comprises abroad spectrum of vibration frequency components. Thefrequency component at the natural resonant frequencyof the blades has the greatest amplitude. In the pre-ferred embodiment, the damper 40 is primarily effectivefor damping the first fundamental of the natural resonantfrequency of the blades, however, any suitable dampingcharacteristics may be used.[0025] Generally, substantially uniform contact issought between the surfaces 44,54. To maintain suchcontact, the damper main body 50 and damping surface54 should not extend into the transition portion 46 of theplatform radially inner surface 30. This is primarily dueto physical tolerances on the surfaces. Consequently,the dimensions of the damping surface 54 are substan-tially limited by features of the platform radially inner sur-face 30.[0026] The extended ends 52 each have a proximalend, which transitions into the main body 50, and a distalfree end, which is free. Clearances 55, between the ex-tended ends 52 and the transition portion 46 of the ra-dially inner surface 30 of the platform 28, obviate inter-ference between those parts to allow uniform continu-ous contact between the damping surface 54 and thedamping portion 44 of the platform radially inner surface

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30. In the preferred embodiment, one of the extendedends 52 is upstream and the other is downstream, there-by extending the damper 40 in the axial direction, i.e.the direction from the platform leading edge 32 to theplatform trailing edge 34. The extended ends 52 arepreferably tapered to accommodate stress, graduallyreducing in thickness from proximal end to distal end.This taper also allows the extended ends 52 to extendroughly halfway through the transition portion 46, whilestill maintaining the clearances 55. In the preferred em-bodiment, the distal ends of the extended ends 52 arerounded. However, it will be apparent to those of ordi-nary skill in the art that the extended ends 52 may haveany other orientation and shape which is suitably adapt-ed to support the seal 42, avoid contact with the platformradially inner surface 30, and accommodate the distri-bution of stress. Furthermore, although the extendedends 52 shown in the illustrated embodiment appearsimilar, the extended ends need not have such similarity.[0027] The damper 40 includes a radially inner sup-port surface 56 which supports the seal 42. In the illus-trated embodiment, the support surface 56 extends thelength of the damper 40, opposite the damping surface54. As such, a significant portion of the support surface56 is comprised of the extended ends 52, thereby allow-ing the support surface 56 to provide greater support forthe seal than that provided by the main body 50 alone.The contour of the support surface 56 should be adapt-ed to provide the desired support for the seal 42 in theparticular application. In the illustrated embodiment, thesupport surface 56 is substantially planar. However, itwill be appreciated that, any other suitable shape, loca-tion, proportion and contour for the support surface 56may also be used. The damper further comprises a pairof nubs 58 adapted to keep the damper 40 properly po-sitioned with respect to the adjacent rotor blade (notshown).[0028] The damper should comprise a material andshould be manufactured by a method which is suitablefor the high temperature, pressure and centrifugal forcefound within the turbine. In the best mode embodiment,a cobalt alloy material, American Metal Specification(AMS) 5382, and fabrication by casting, have beenfound suitable for high pressure turbine conditions; how-ever any other suitable material and method of fabrica-tion known to those skilled in the art may also be used.[0029] The seal has a supported portion 60, in phys-ical contact with the damper support surface 56, and apair of sealing portions 62. The sealing portions 62 areadapted to provide seals against the sealing portion 48of the platform radially inner surface 30. Each of thesealing portions has a proximal end, transitioning intothe support portion 60 and a distal end, which is prefer-ably free. The shapes of the supported and sealing por-tions 60, 62 closely conforms to that of the damper sup-port surface 56 and sealing portion 48 of the platformradially inner surface 30, respectively. In the illustratedembodiment, the supported portion 60 is substantially

planar and the sealing portion 62 closely conforms tothe inner surface of the platform supports 36,38. An ar-cuate bend at the transition between the supported por-tion 60 and the sealing portion 62 is preferred.[0030] The illustrated shape allows the seal 42 to re-ceive radial support from the damper 40 and providesealing against leakage. It should be noted that in theillustrated embodiment, the sealing portions of the sealare forced into closer proximity with the sealing surfacesof the platform by centrifugal force. However, any othershape known to those of ordinary skill in the art whichis suitably adapted to provide the desired sealing mayalso be used. Furthermore, although the sealing por-tions 62 shown in the illustrated embodiment appearsimilar, the sealing portions need not have such similar-ity.[0031] The seal should comprise a material andshould be manufactured by a method which is suitablefor the high temperature, pressure and centrifugal forcefound within the turbine. The seal 42 typically comprisesa thin sheet of metal to allow the seal to flex to conformwith the sealing portion 48 of the platform radially innersurface 30. In the best mode embodiment, the seal 42comprises a cobalt alloy material, American Metal Spec-ification (AMS) 5608, and is cut by laser, to a flat pattern.A punch and die is then used to form the rest of the seal42 shape. However, any other suitable material andmethod of fabrication known to those skilled in the artmay also be used.[0032] FIGS. 3 and 4 illustrate further details of thedamper 40. Referring now to FIGS. 3 and 4 in top viewand side perspective views of the damper 40 of the pre-ferred embodiment, the pair of nubs 58 are disposed ona concave side 68 of the damper 40. The damper 40also comprises a convex side 69 which interfaces to theconcave side 16 (FIG. 1) of the rotor blade 10. However,those of ordinary skill in the art should recognize thatthe damper 40 has a curved shape to accommodateblade 10 considerations which are not relevant to thepresent invention.[0033] The incorporation of the extended ends 52 inthe damper and seal configuration of the present inven-tion provides greater support of the seal 42 to reduceundesirable seal deformation under centrifugal forceloading conditions. This improves the effectiveness ofthe seal 42, thereby reducing gas leakage and improv-ing the efficiency of the turbine.[0034] The incorporation of the extended ends 52 canalso improve damper performance. Since the weight ofthe damper 40 includes the weight of the main body 50and the extended ends 52, the inclusion of extendedends 52 allows greater weight distribution flexibility, anda more uniform distribution of the damper friction forcebetween two adjacent blades. For example, as will becommercially embodied, the weight of the damper of theillustrated embodiment is substantially the same as thatof prior art dampers. However, without the extendedends, the damper did not apply friction force of equal

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magnitude to the two adjacent blades. With the additionof the extended ends, there is more flexibility in the de-sign of the damper to best provide the desired damping.The present damper is longer axially, narrower from sideto side, and thicker from damping surface to support sur-face, than the previous damper. As a result, the frictionforce provided by the present damper is split more even-ly between the two adjacent blades. In the preferred em-bodiment this provides improved vibration dampingcompared to that where the friction force is not uniformlydistributed.[0035] The seal of the preferred embodiment of thedamper and seal configuration of the present inventionis illustrated in FIGS. 5,6. Referring now to FIGS. 5,6,in top and side views, respectively, of the seal 42 in thepreferred embodiment, the seal 42 has a projection 70.The projection 70 is adapted to provide physical inter-ference when the damper and seal are installed invertedin relation to each other, e.g. with seal 42 betweendamper 40 and platform radially inner surface 30, butnot when the damper and seal are installed properly. Up-on such improper installation, the interference does notallow the damper and seal to fit in the assembly. Theprojection 70 thus prevents such misassembly.[0036] In the illustrated embodiment, the projection istab shaped, having a major surface 72 which extendsfrom and is substantially perpendicular to the supportportion 60. The direction in which the projection 70 ex-tends from the support portion 60 is generally oppositeto the direction of the sealing portions 62. When the sealis improperly installed between the damper and the plat-form radially inner surface 30 (FIGS. 1,2), the projection70 creates an interference which does not allow boththe damper and seal to fit between the platform radiallyinner surface 30 and the pair of protrusions 64 (FIG. 2),thus preventing misassembly. This improves effective-ness of the damper and seal and improves the reliabilityof the turbine.[0037] The height of the projection 70 above the sup-port surface 60 is less than the thickness of the damper40. Consequently, when the damper and seal are in-stalled in proper relation to each other, the projection 70does not interfere with the contact between the dampingsurface 54 of the damper 40 and the damping portion44 of the platform radially inner surface 30. However, itwill be apparent to those of ordinary skill in the art, thatthe projection 70 may have any suitable shape whichallows it to create an interference when the damper andseal configuration is not properly installed, including butnot limited to a cylindrical shape. In the illustrated em-bodiment, the projection 70 is integral to the support por-tion 60, being formed as part of the laser cut, punch anddie process described above, and therefore does notsignificantly increase the cost of the seal 42; however,any other suitable method for forming and attaching theprojection 70 to the seal 42 may be used.[0038] Those of ordinary skill in the art should alsorecognize that the seal 42, like the damper 40, has a

curved shape to accommodate blade 10 considerationswhich are not relevant to the present invention.[0039] The location of the seal and damper is illustrat-ed in FIG. 7. Referring now to FIG. 7, prior to installationof the seal 42 into the blade 10, the blade 10 furthercomprises a pair of stand-offs 74. The pair of stand-offs74 are adapted to help keep the damper 40 (FIGS. 1,2)and seal 42 in proper position with respect to the blade10, i.e. the platform radially inner surface 30 and theneck 65. However, the stand-offs 74 do not retain theseal 42 in the proper axial position, i.e. from platformleading edge 32 to platform trailing edge 34. Conse-quently, a locator 76 in the support surface 60 has beenadded to the seal 42. When the seal 42 with the locator76 is installed in the blade 10, the locator 76 interfaceswith the stand-offs 74, and the combination holds theseal 42 in the desired axial position. In the illustratedembodiment, the locator 76 is a notch, or scallop, whichhas a generally curving rectangular shape (FIG. 5) andspans both sides of the projection 70. This shape isadapted to properly interface with the stand-offs 74,which are located on the concave surface of the neck65. It will be apparent that the locator 76 can be suitablyadapted to operate with any stand-off configuration orother feature on the blade 10 which can provide a catchfor the locator. It should also be obvious that instead ofa notch, the locator 76 could be a tab that fits betweenthe stand-offs 74. In the illustrated embodiment, the lo-cator 76 in the support surface 60 is formed as part ofthe laser cut, punch and die process described above,and therefore does not significantly increase the cost ofthe seal 42, however, any other suitable method forforming the locator 76 may be used.[0040] The locator 76 in the seal 42 provides im-proved axial alignment of the seal 42 with the sealingportion 48 of the platform radially inner surface 30. Im-proved alignment results in improved seal effective-ness, reduced leakage and increased turbine efficiency.[0041] Although the damper of the present inventionis disclosed as having a pair of extended ends, it shouldbe obvious to those of ordinary skill in the art that someapplications may only require one such extended endwhile others may require more than two such extendedends. Similarly, although the seal of the present inven-tion is disclosed as having sealing portions 62, it shouldbe obvious to those of ordinary skill in the art that someapplications may only require one and others may re-quire more than two such sealing portions.[0042] Those skilled in the art should also recognizethat although the illustrated embodiment of the presentinvention is intended for use in a second stage highpressure turbine application, the present invention maybe suitably adapted for other turbine applications, in-cluding but not limited to other high pressure turbine ap-plications. Furthermore, although the damping systemfor low pressure turbine applications typically involvedamping with a tip shroud, it should be obvious to thoseof ordinary skill in the art that the present invention may

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also be suitably adapted for low pressure turbine appli-cations.[0043] Lastly, although the damper and seal are dis-closed as a combination, it should be obvious that thedamper may also be used without the seal and the sealmay be used without the damper.[0044] While the particular invention has been de-scribed with reference to a particular preferred embod-iment, this description is not meant to be construed in alimiting sense. It is understood that various modifica-tions of the preferred embodiment, as well as additionalembodiments of the invention, will be apparent to per-sons skilled in the art upon reference to this description,without departing from the scope of the claims append-ed hereto.

Claims

1. A rigid vibration damper (40) for use with a turbinerotor blade (10) and a seal (42) in a gas turbine en-gine, the turbine rotor blade (10) having an airfoilportion (22), a platform (28), a neck (65), and a root(66), the blade platforms (28) each having a radiallyouter surface (26), and a radially inner surface (30)connected by the blade neck (65) to the blade root(66), the radially inner surface (30) having a damp-ing portion (44), and the seal having at least onesealing portion (62) extending from a supportedportion (60), said at least one sealing portion (62)adapted, in use, to provide sealing in combinationwith the sealing portion (48) of adjacent blade plat-form radially inner surfaces, the rigid damper com-prising:

a main body (50) having a damping surface (54)adapted, in use, to contact the damping portion(44) of adjacent platform radially inner surfaces(30) and to provide a friction force on the damp-ing portions;

characterised in that said main body (50) al-so has a support surface (56) for supporting saidsupported portion of said seal in use, by means ofwhich said damper is supported, said support sur-face being larger than said damping surface (54),and at least one end (52) axially extended from saidmain body (50) adapted, so as in use, to be spacedat a clearance from the adjacent platform radiallyinner surfaces.

2. A vibration damper as claimed in claim 1 in combi-nation with said seal, for use with a turbine blade(10) with a radially inner surface (30) having adamping portion (44), a sealing portion (48), and atransition portion (46) located between them;wherein said seal is a flexible seal (42); and

wherein said at least one extended end (52)

and said main body of said damper are disposed inuse between adjacent blade platform radially innersurfaces (30) and said supported portion (60) ofsaid seal (42), and said main body and said at leastone extended end (52) each have a support surface(56) for contact with said supported portion (60) ofsaid seal (42).

3. The apparatus of claim 1 or 2 wherein said at leastone extended end (52) extends said damper in anaxial direction.

4. The apparatus of any of claims 1 to 3 wherein saidat least one extended end (52) is tapered.

5. The apparatus of any of claims 1 to 4 wherein saiddamper comprises a pair of tapered ends (52) whichextends said damper (40) in the axial direction fromupstream fillet runout to downstream fillet runout.

6. The apparatus of any of claims 2 to 5 wherein saidsupport surface (56) of said damper (50) has a sub-stantially planar surface.

7. The apparatus of any of claims 2 to 6 wherein saiddamping (54) and said support surfaces (56) of saiddamper (40) have substantially planar surfaces,and said support surface (56) is generally opposedto said damping surface (54).

8. The apparatus of any of claims 2 to 7 wherein saidsupported portion (60) of said flexible seal (42) fur-ther comprises a locator (76) such as a notch, whichin use interfaces with the blade (10) when the flex-ible seal (42) is installed, to positively position andmaintain the flexible seal in the proper axial posi-tion.

9. The apparatus of any of claim 2 to 8 wherein saidflexible seal (42) further comprises a projection (70)such as a tab projecting from said supported portion(60) which provides an interference with the blade(10) when the flexible seal is improperly installedwith the blade.

10. The apparatus of any of claims 2 to 9 wherein saidflexible seal (42) comprises a pair of sealing por-tions (62) and said supported portion (60) of saidflexible seal (42) is substantially planar, said sealhaving an arcuate bend disposed between saidsupported portion and each of said pair of sealingportions.

11. A rotor assembly for a gas turbine engine, compris-ing:

a plurality of blades (10) mounted on the disc,each blade (10) having an airfoil portion (22), a

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platform (28), a neck (65) and a root (66), theblade platforms (28) each having a radially out-er surface (26) and a radially inner surface (30)connected by the blade neck (65) to the bladeroot (66) and having a damping portion (44), asealing portion (48) and a transition portion (46)located between them;

and further comprising a damper or a seal anddamper combination as claimed in any precedingclaim.

Patentansprche

1. Steifer Schwingungsdmpfer (40) zur Verwendungmit einer Turbinenrotorlaufschaufel (10) und einerDichtung (42) in einer Gasturbinenmaschine, wobeidie Turbinenrotorlaufschaufel (10) einen Str-mungsprofilbereich (22), eine Plattform (28), einenHals (65) und eine Wurzel (66) hat, wobei die Platt-formen (28) jeweils eine radial uere Oberflche(26) und eine radiale innere Oberflche (30) haben,die durch den Laufschaufelhals (65) mit der Lauf-schaufelwurzel (66) verbunden sind, wobei die ra-dial innere Oberflche (30) einen Dmpfungsbe-reich (44) hat, und wobei die Dichtung mindestenseinen Dichtungsbereich (62) hat, der sich von ei-nem abgesttzten Bereich (60) erstreckt, wobeimindestens ein Dichtungsbereich (62) angepasstist, bei Verwendung eine Abdichtung in Kombinati-on mit dem Dichtungsbereich (48) der radial inne-ren Oberflchen der benachbarten Laufschaufel-plattformen zu schaffen, wobei der steife Dmpferaufweist:

einen Hauptkrper (50) mit einer Dmpfungs-oberflche (54), die daran angepasst ist, beiVerwendung den Dmpfungsbereich (44) radi-al innerer Oberflchen (30) benachbarter Platt-formen zu berhren und eine Reibkraft an denDmpfungsbereichen zu schaffen;

dadurch gekennzeichnet, dassder Hauptkrper (50) auch eine Absttzoberflche(56) zum Absttzen des abgesttzten Bereichs derDichtung bei Verwendung hat, mittels der derDmpfer abgesttzt ist, wobei die Absttzoberfl-che grer ist als die Dmpfungsoberflche (54),und mindestens ein Ende (52), welches axial vondem Hauptkrper (50) fortgesetzt ist, daran ange-passt ist, bei Verwendung mit einem Spielraum vonden radial inneren Oberflchen der benachbartenPlattformen beabstandet zu sein.

2. Schwingungsdmpfer nach Anspruch 1 in Kombi-nation mit der Dichtung zur Verwendung mit einerTurbinenlaufschaufel (10) mit einer radial inneren

Oberflche (30), die einen Dmpfungsbereich (44),einen Dichtungsbereich (48) und einen zwischendiesen angeordneten bergangsbereich (46) hat,wobei die Dichtung eine flexible Dichtung (42) ist;undwobei das mindestens eine verlngerte Ende (52)und der Hauptkrper des Dmpfers bei Verwen-dung zwischen radial inneren Oberflchen (30) be-nachbarter Laufschaufelplattformen und dem ab-gesttzten Bereich (60) der Dichtung (42) angeord-net sind, und wobei der Hauptkrper und das min-destens eine verlngerte Ende (52) jeweils eine Ab-sttzoberflche (56) zum Kontakt mit dem abge-sttzten Bereich (60) der Dichtung (42) haben.

3. Vorrichtung nach Anspruch 1 oder 2, wobei dasmindestens eine verlngerte Ende (52) den Dmp-fer in axiale Richtung verlngert.

4. Vorrichtung nach einem der Ansprche 1 bis 3, wo-bei das mindestens eine verlngerte Ende (52) ver-jngt ist.

5. Vorrichtung nach einem der Ansprche 1 bis 4, wo-bei der Dmpfer ein Paar von verjngten Ende (52)aufweist, die dem Dmpfer (40) in der Axialrichtungvon dem strmungsaufwrtigen Ausrundungsaus-lauf bis zu dem strmungsabwrtigen Ausrun-dungsauslauf verlngern.

6. Vorrichtung nach einem der Ansprche 2 bis 5, wo-bei die Absttzoberftche (56) des Dmpfers (50)eine im wesentlichen planare Oberflche hat.

7. Vorrichtung nach einem der Ansprche 2 bis 6, wo-bei die Dmpfungsoberflche (54) und die Ab-sttzoberflche (56) des Dmpfers (40) im wesent-lichen planare Oberflchen haben, und wobei dieAbsttzoberflche (56) der Dmpfungsoberflche(54) im wesentlichen gegenberliegt.

8. Vorrichtung nach einem der Ansprche 2 bis 7, wo-bei der abgesttzte Bereich (60) der flexiblen Dich-tung (42) ferner ein Positionierelement (76), bei-spielsweise eine Kerbe aufweist, die bei Verwen-dung mit der Laufschaufel (10) eine Verbindungs-stelle bildet, wenn die flexible Dichtung (42) instal-liert ist, um die flexible Dichtung zuverlssig in derkorrekten Axialposition zu positionieren und festzu-halten.

9. Vorrichtung nach einem der Ansprche 2 bis 8, wo-bei die flexible Dichtung (42) ferner eine Vorsprung(70), beispielsweise eine von dem abgesttzten Be-reich (60) vorstehende Fahne hat, der fr eine St-rung mit der Laufschaufel (10) sorgt, wenn die fle-xible Dichtung mit der Laufschaufel unkorrekt in-stalliert ist.

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10. Vorrichtung nach einem der Ansprche 2 bis 9, wo-bei die flexible Dichtung (42) ein Paar von Dich-tungsbereichen (62) aufweist und der abgesttzteBereich (60) der flexiblen Dichtung (42) im wesent-lichen planar ist, wobei die Dichtung eine gekrmm-te Biegung hat, die zwischen dem abgesttzten Be-reich und jedem der Dichtungsbereiche aus diesemPaar angeordnet ist.

11. Rotoranordnung fr eine Gasturbinenmaschine,aufweisend:

eine Mehrzahl von Laufschaufeln (10), die ander Scheibe angebracht sind, wobei jede Lauf-schaufel (10) einen Strmungsprofilbereich(22), eine Plattform (28), einen Hals (65) undeine Wurzel (66) aufweist, wobei die Lauf-schaufelplattformen (28) jeweils eine radial u-ere Oberflche (26) undeine radial innere Oberflche (30) haben, diemit dem Laufschaufelhals (65) mit der Lauf-schaufelwurzel (66) verbunden sind und einenDmpfungsbereich (44), einen Dichtungsbe-reich (48) und einen zwischen diesen angeord-neten bergangsbereich haben; undferner aufweisend einen Dmpfer- oder eineDichtungs- und -Dmpfer-Kombination, wie ineinem der vorangehenden Ansprche bean-sprucht.

Revendications

1. Amortisseur de vibrations rigide (40) destin treutilis avec une aube de rotor de turbine (10) et unjoint d'tanchit (42) dans un moteur de turbine gaz, l'aube de rotor de turbine (10) comportant unepartie de profil arodynamique (22), une plate-for-me (28), un col (65) et une racine (66), les plates-formes d'aube (28) comportant chacune une surfa-ce radialement extrieure (26) et une surface radia-lement intrieure (30) relies par le col d'aube (65) la racine d'aube (66), la surface radialement int-rieure (30) comportant une partie d'amortissement(44) et le joint d'tanchit comportant au moinsune partie d'tanchit (62) s'tendant partird'une partie supporte (60), ladite au moins unepartie d'tanchit (62) tant adapte pour, en fonc-tionnement, assurer l'tanchit en combinaisonavec la partie d'tanchit (48) des surfaces radia-lement intrieures des plates-formes d'aubes adja-centes, l'amortisseur rigide comprenant :

un corps principal (50) comportant une surfaced'amortissement (54) adapte pour, en fonc-tionnement, venir en contact avec la partied'amortissement (44) de surfaces radialementintrieures de plates-formes adjacentes (30) et

pour appliquer une force de frottement aux par-ties d'amortissement ;

caractris en ce que ledit corps principal(50) comporte galement une surface de support(56) pour supporter ladite partie supporte duditjoint d'tanchit en fonctionnement, par laquelleledit amortisseur est support, ladite surface desupport tant plus grande que ladite surfaced'amortissement (54), et au moins une extrmit(52) s'tendant axialement partir dudit corps prin-cipal (50) adapte pour, en fonctionnement, tre es-pace d'une certaine distance des surfaces radia-lement intrieures de plates-formes adjacentes.

2. Amortisseur de vibrations selon la revendication 1en combinaison avec ledit joint d'tanchit, desti-n tre utilis avec une aube de turbine (10) avecune surface radialement intrieure (30) comportantune partie d'amortissement (44), une partie d'tan-chit (48) et une partie de transition (46) situe en-tre elles, dans lequel ledit joint d'tanchit est unjoint d'tanchit flexible (42) ; et

dans lequel ladite au moins une extrmittendue (52) et ledit corps principal dudit amortis-seur sont disposs, en fonctionnement, entre dessurfaces radialement intrieures de plates-formesd'aubes adjacentes (30) et ladite partie supporte(60) dudit joint d'tanchit (42), et ledit corps prin-cipal et ladite au moins une extrmit tendue (52)comportent chacun une surface de support (56)destine venir en contact avec ladite partie sup-porte (60) dudit joint d'tanchit (42).

3. Dispositif selon la revendication 1 ou 2, dans lequelladite au moins une extrmit tendue (52) prolon-ge ledit amortisseur dans une direction axiale.

4. Dispositif selon l'une quelconque des revendica-tions 1 3, dans lequel ladite au moins une extr-mit tendue (52) est conique.

5. Dispositif selon l'une quelconque des revendica-tions 1 4, dans lequel ledit amortisseur comprenddeux extrmits coniques (52) qui prolongent leditamortisseur (40) dans la direction axiale d'une sor-tie de cong amont une sortie de cong aval.

6. Dispositif selon l'une quelconque des revendica-tions 2 5, dans lequel ladite surface de support(56) dudit amortisseur (50) a une surface sensible-ment plane.

7. Dispositif selon l'une quelconque des revendica-tions 2 6, dans lequel lesdites surfaces d'amortis-sement (54) et de support (56) dudit amortisseur(40) ont des surfaces sensiblement planes, et laditesurface de support (56) est gnralement oppose

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ladite surface d'amortissement (54).

8. Dispositif selon l'une quelconque des revendica-tions 2 7, dans lequel ladite partie supporte (60)dudit joint d'tanchit flexible (42) comprend, enoutre, un dispositif de positionnement (76) telqu'une encoche, qui, en fonctionnement, raliseune interface avec l'aube (10) lorsque le jointd'tanchit flexible (42) est install, afin de posi-tionner et de maintenir correctement le joint d'tan-chit flexible dans la position axiale correcte.

9. Dispositif selon l'une quelconque des revendica-tions 2 8, dans lequel ledit joint d'tanchit flexi-ble (42) comprend, en outre, une protubrance(70), telle qu'une patte faisant saillie de ladite partiesupporte (60), qui interfre avec l'aube (10) lors-que le joint d'tanchit flexible n'est pas correcte-ment install par rapport l'aube.

10. Dispositif selon l'une quelconque des revendica-tions 2 9, dans lequel le joint d'tanchit flexible(42) comprend deux parties d'tanchit (62) et la-dite partie supporte (60) dudit joint d'tanchitflexible (42) est sensiblement plane, ledit jointd'tanchit comportant un coude en forme d'arcdispos entre ladite partie supporte et chacunedesdites deux parties d'tanchit.

11. Ensemble de rotor pour un moteur de turbine gaz,comprenant :

une pluralit d'aubes (10) montes sur le dis-que, chaque aube (10) comportant une partiede profil arodynamique (22), une plate-forme(28), un col (65) et une racine (66), les plates-formes d'aube (28) comportant chacune unesurface radialement extrieure (26) et une sur-face radialement intrieure (30) relies par lecol d'aube (65) la racine d'aube (66) et com-portant une partie d'amortissement (44), unepartie d'tanchit (48) et une partie de transi-tion (46) situe entre elles ;et comprenant, en outre, un amortisseur ou unecombinaison de joint d'tanchit et d'amortis-seur selon l'une quelconque des revendica-tions prcdentes.

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