PDF Publication Title:
Text from PDF Page: 009
US 6,439,844 B1 12 TURBINE BUCKET COVER AND BRUSH SEAL BACKGROUND OF THE INVENTION prevented, With the result that turbine performance is enhanced. By sealingly engaging the cover portions to one another along the area of contact betWeen the tips of the bristles and the outer cover surfaces, the potentially dam aging effect on the seal bristle pack by the radial out?oW is eliminated. Particularly, the adjoining edges of the covers are overlapped With one another. For example, lap joints are formed betWeen the adjoining edges. In another form, tongue-and-groovejointsmay beprovided.Inastilfurther form, additional cover segments may overlie the covers in staggered circumferential relation to the underlying covers such that the gaps betWeen adjoining underlying covers are sealed by the overlying covers. In another preferred embodiment, in a turbine having a plurality of rotatable buckets, a stationary shroud surround ingtherotatablebuckets,anda?uidmedium?oWpath through the turbine, sealing betWeen the buckets and the stationary shroud is accomplished by a plurality of arcuate covers carried by radial outer ends of the buckets for rotation With the buckets about an axis of the turbine in a predeter minedcircumferentialdirection,thecovershavingleading andtrailingedgesinthedirectionofrotationofthebuckets, a brush seal comprising a plurality of bristles projecting from the shroud for sealingly engaging outer surfaces of the covers, and a joint betWeen circumferentially adjacent cov erssealingadjoiningleadingandtrailingedgesthereofto one another, thus substantially precluding radial out?oW of the ?uid medium onto the bristles as the buckets and covers rotate relative to the brush seal. In a further preferred embodiment, in a turbine having a pluralityofrotatablebuckets,astationaryshroudsurround ing the rotatable buckets, and a ?uid medium ?oW path through the turbine, sealing betWeen the buckets and the stationary shroud is accomplished by a plurality of arcuate covers carried by radial outer ends of the buckets for rotation Withthebucketsaboutanaxisoftheturbineinapredeter minedcircumferentialdirection,thecovershavingadjoining edges, a brush seal comprising a plurality of bristles pro jectingfromtheshroudforsealinglyengagingoutersurfaces of the covers, and a joint betWeen circumferentially adjacent coversincludingatleastportionsoftheadjoiningedges overlappingoneanotherandsealinglyengagingtheadjacent covers to one another at axial locations corresponding to axial locations of the cover surfaces engaged by the bristles, to substantially preclude radial out?oW of the ?uid medium pasttheoverlappingportionsontothebristles. BRIEF DESCRIPTION OF THE DRAWINGS This invention relates to covers carried by the tips of turbine buckets and brush seals surrounding and engaging the bucket covers, and more particularly relates to seals betWeen the adjoining edges of bucket covers for minimiZ ing or eliminating radial out?oW of the ?uid medium ?oW ing through the turbine onto the bristles of the surrounding brush seal. 10 As set forth in US. Pat. No. 6,036,437, of common assignee hereWith, turbine bucket covers and brush seals surroundingthebucketcoversforsealingbetWeenupstream and doWnstream portions of a turbine stage are knoWn. Turbine bucket covers are typically provided in either of tWo forms. A bucket and a discrete bucket cover are often integrally cast one With the other and applied to the turbine Wheel.Adjoiningedgesoftheadjacentcoverstypicallyform 20 a generally Z-shaped joint as vieWed in a radial direction. Other bucket covers are provided in the form of a cover band Which spans tWo or more buckets. The bucket cover bands typically have openings for receiving tenons formed on the tipsofthebucketsandWhichtenonsarepeenedtosecurethe 25 cover bands to the bucket. Like the integrally cast buckets and covers, the adjoining edges of the cover bands engage one another, generally in a Z-shaped joint When vieWed radialy. AsWillbeappreciated,thepressureofthe?uidmedium 30 Within the ?oW path through the turbine, for example, steam ?oWing in the steam path of a steam turbine, is at a signi?cantlyhigherpressurethanthesteampressureradially outWardly of the covers. This difference in pressure causes radialout?oWofthe?uidmediumthroughthegapsbetWeen 35 the edges of adjoining covers. These gaps permit both radial and axial out?oW of the ?uid medium and turbine perfor mance is thereby degraded. Labyrinth seals and/or brush seals are typically employed in the shroud surrounding the bucketsandcoversandthosesealscanlimittheperformance 40 lossesattributabletoaxial?oW throughandaroundthegaps. Brush seals also afford an added performance bene?t over the use of labyrinth seals. HoWever, turbine bucket tip brush seals are affected by radial ?oW in the region of the bristle pack.Theradial?oWintothebristlepackthroughtheradial 45 gaps betWeen the bucket covers causes bristle fatigue and failure. That is, the discrete ?oWs of the ?uid medium radiallyoutWardlythroughthegapsbetWeenadjacentbucket covers tend to de?ect the bristles in an outWard direction, as Well as to splay the bristles in an axial direction. Thus, for every pass of a gap by a given bristle location, the bristles are de?ected both axially and radially by the radial ?oW. Moreover, the bristles attempt to recover before the next radial outWard ?oW repeats those de?ections. These de?ec tion cycles cause bristle fatigue and failure. It Will be appreciated that for a 60 HZ machine having eighty covers and gaps in a stage, a 40,000 HZ stimulus isprovided to the bristle pack at the various circumferential locations of the bristles about the turbine Wheel. BRIEF SUMMARY OF THE INVENTION 60 normaltotheaxisofrotationoftheturbinebucket;and FIG. 8 is a cross-sectional vieW illustrating the engage In accordance With a preferred embodiment of the invention, the gaps betWeen the adjoining edges of the coversaresealedtotheextentthattheradial?oW leakageis minimiZedoreliminated.Theseportionsoftheedgesofthe 65 adjoining covers interlock With one another such that radial leakage, e.g., steam, from the ?oW path is minimiZed or ment of the bristles and the bucket cover. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a plurality of buckets 10 forming part of a rotating component of turbomachinery such as a turbine 15 FIG. 1 is a vieW partly in cross section and in elevation taken in a radial plane along the axis of a turbine, illustrating 50 buckets, bucket covers and bristles forming an improved seal according to a preferred embodiment of the invention; FIG. 2 is a partial schematic vieW in an axial direction illustrating buckets, bucket covers and a brush seal segment according to the prior art; 55 FIGS. 3, 4, 5 and 6 are partial schematic vieWs in an axial direction illustrating various preferred embodiments of the invention. FIG. 7 illustrates a plurality of bucket covers and a brush seal looking in a radially inWard direction doWn to a planePDF Image | TURBINE BUCKET COVER AND BRUSH SEAL
PDF Search Title:
TURBINE BUCKET COVER AND BRUSH SEALOriginal File Name Searched:
US6439844.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)