the application of flexible couplings for turbomachinery

8/15/2019 The Application of Flexible Couplings for Turbomachinery

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by

Jon Macuso

Manger, Eninerin

Zun Indstis, Incopoat

Ei, Pnnsylvania

. (ey Gios

Mae, Culin nginrin

Las Aerospae owe Transmission Cooration

Utica, New Yk

d

o

Vi Prsidnt Ennr an Thnolo

Kop-Flex, Inooat

Baltimo, arylan

]o R. acso has ee workg ivarious capacies at Zur Idstres In- corpoted, echanicl Dies ivisio or th e at 2 years. Stat as a -earch an veopmet giee hemoed to St ieer to aagerof Proect Egieerig ad hi presetositio o age o ierig (yars).

H has ee ivolved wit m r- each a deve lom et prects rig

o couplig. He is coivte r our dustries multile co -

volted diarag oplig, "Amerex, "Aeex H adur ultile covoluted lin couings.

r. cuso grauatedfo Gao Uiversity with a . S. i echa ical gierig, a d ha M. . i Egieerig Sci-ece r Psylvaia tate versiy.

H is carig the SME omittee o oupligs adlutchs I additi, he is a member of the AI SE o the illDrve ommitte, GMA ouping Comittee, and th APICommittee on ouig r Secial urpoe Appliatios.

. (Bay Gbo s is the aa erof oupli Egieerin for ucas Aero-pace e miio Cororatio,ormerly edi), i Utica, Ne Yor.

H h as desing coulisf botairc ad indstrial pplicat ios for ot of his 3 year care. A gaduate te ier of oct a nd a lice sdProessiol gir th St t o wrk he hs eed serl paper o

coplis to S ME th e rbomaceryyoi d thr orgizat io. a oft de tchnial pesaons o coupli t ieracti ith rott- i m ch i t e a po sore B endix, Dessea,xo obl, the Vbrtio Istitt E, a the

1

ort E. uyo, ie idet ofEiering and Techolo or o-

lex Icorporated, is resol or di-rctig technical opeatios, icludngegeig deig esearch, prod-uc develot. ur hi uteeyear teure with KoFle foery tePowr Trasmissio Dvisio persoay, cororated), h e in-

strumet in the deg o rfor-ace gear d diahragm cois and

i he deelet of th e KFex@ high erfora c co-li. He h s coaut hor ad sted a o ro co- plg toic o E, th rbom ach inery ymo i, nd th eVbrato Itiute.

M. uyo received a .S . degree i chaic ieer- i 97 from RosHua I titut of Tcho lo d i amemer a SM a nd AS .

ODUO

lexible coupling re too oe tougt o iee oarware rter tan a ital prt o ower rann em Virually eey uer h a tory bout a p o eimtit coupng roblem. ometie te coulng i te il nand jut i not eorm needed, but oen t lin oly reacting to a oncealed rol ad oulder te lor t el culrit e baic o oupling ein tioill be ented i reentaton i intn t teqipmn ur an ette undetand te f ouling, ow t acomlie toe t, o to fn utiliz exble couplin, nd o to lce t re eo couling roblem

So o te ie dicue il u a cu-ling bic rincl ad tr, t dirn an ible eleent coulng, electing ouig f n -lictio, rerottin er couling \t xile len cou-lig, ad Stadard Oating l


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142 EE D F H E EHEH B HEY YM

e addressed, such as the rotordynamic eects of couplings,ynamic balance, installation rocedures, maintenance consid-rations, and indage eects.

WHY A FLEXBLE OUPLG?

Ideally, process machines combine both the driving mecha-nism and the uid handlin mechanism in one device. The com-pressor in the modern refrigerator is just such an ideal machine.Unfortuately, though, most large sized uid handlingmachines just aren't made that .

Historically, some driving machine as connected to someload machine with anges on each machine sha and bolted to-gether (Figure 1). Experience, in the form of a lot of brokenshafts and wrecked macines, orced deelopment of variousinds of exible couplings to accommodate he reality that onecannot align anor keep to machines suciently aligned.There are exceptions to this: most large steam turbogeneratorsand a fe large gas turbinegenerators utilize a "rigid couplingwhic accommodates ver little misalignment. This is ac-complished by expending a ot of hard work matching the bea�g and support systems for the to machines.

Howeer, the majority of machines require exible couplingsto accommodate the misalignment. Generally, machines can be

set up quite accurately, but here are many forces whic pushthem out. Handling hot and cold uids cause most of the move-ent in the vertical and axial directions (Figure 2. he erticalmotions are the result of supprt structure groth and the axialmotions are the resul of the dirence in case s rotor growt,case groth onl, or rotor growth only depending on the locatinof the thrust bearing. Horizontal (sideways motions are usuallyaused by piping rces Figure 3) or by dierential solar heatingFiure The piping forces can be caused by either tempera-ture changes or by pressure changes.

r:: Jl

ur Rgd oupgs

The thermal growth of the mahines can generally be calcu-

ated with sucien accuracy from knon theral data and fromavailable dimensions. Some tpical machine aial displacementsre shown in Figure 5

During startup, the heier husing takes approximatelwice as much time to heat u as the ligher shaft. This causes agreater axial requirement duing starup fo a machine such aD, th the sha expanding to position until the casing ex-pands to pull it back to position L .

fact of life that machinery engineers must lie it is thtmisalignment causes vibratio. t isn't really the misalignentthat causes te viration, but the force Figure 6 tht a mis-aligne coulig puts on the macine that causes the mahineto ibrae. Al ongs sbject o isgnen ad torque

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Fgur Fors Du to Hadg Fuds of D tTmrtur

.

Fgur 3. Fors Du to Pg Exa so

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Fgur 4 stto u to ar Hatg

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1 E ED F HE EHE EH B MHEY YM

VOO

OO

gure 9 iaignment of a Crown oth Couing.

aphrag plgs Fgr 10) r hese applas areaalal as rs (Fgr 1):

Tapered red lple led daphragBh shapes hae s e pe rle da ha helps

rede sze rease el ad rl sss eras aphrag pes a lasse as plgs halze a sgle r a se res plaes r dahrags r heele eers The rqe rasss pah hrgh hedaphrag eers s he radal dre; r he erdaeer he e r daer r eersa a r pera

Fgure 0 iahrgm Couing

g rqe s see as a shear sress he daphr ee r(s red daphrag pl pall ss a sgle daphrag plae r he ele eer; he le has a r ed prle hh prd es a arale h s s r I prde a p sress d led daphra plg all ses lple darag plashh hae a a prle h pe s ar plgsah he ele eer her ps h lssples r elds ad ras rqe se aer

TAPERED CONTOURE DIAPHRGM

LTIPL COVOLUTE DIAPA

Figur . iahragm e.

The ds plg (Fgr 12) s avaal ber rs; all hae he drvg ad dre ls sae bl rle The ebl sal e ha eah a hadle deped p he legh he aeral bee l Trqe srased y drvg ls pllg rve ls wh ds aeral (eal pses e ) Mr ls gerll prde reaer rq apa rede plg e l

s plgs e her ad se a s rs h laaes r e rg r ds pa Thes d s a a seres aal hles hrgh hh he pas are alera l l ed

separae ages The rqe rasss pa s hrg eage he led j hrgh h e ds eee adjg ls he sed l j a he sedage T he rq s rased hrh h s pa a re ageal he pl erl d prdes aesle sress he ds pa e ers s a desgs ar erel r se he dss are r sallped ree le a r ars reass e agahe all ra rqe he sae aer

There are e as pes d s plg s re 13: Cirr i The lad r rq s rased

hrgh a rd ea asg he er der ( I he


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R 1

isc to be in tensi on and the ote r diameter (OD to be in com-ression To aoid the line ofactio falling outside the disc mate-rial mre bolts than necessary can be required reducingexibilit.

He Disc ore material is left in the disc area where thelargest ending stress occrs, ich reduce tensile stresses atthe bolt connections .

Scalloed Disc By re moin the le ast orked ortion of

the disc it is designe to rodce relatiely uniform tensilestress es across the driing ortion of the dsc and reduce bend-ing stresses at the acor int de to misalignment

Segmented Dischis te tyically has the same oeat-ing characteristics of the other disc tye coulings but ithmanufacturing advatage s

Multile onvoluted DiscThis disc te efers to a ser iesof thin s earaed cooluted sem entd links in a ack assem-bly. Te least orked ortion of the disc i s elminated and se-

aration of the exing area redces fretting corrosion. The con-olutions i ncrease exibility.

gu Disc ou ling

MSLGNMENT

There are three tyes of misalignment Figure 1) a coulingis suet to b an equiment train and which the coulingmust acmmodate angular, oset and axial. The ovewhelm-ing conition is some combination of all three of these at thesame time. ngular misalignment s roduced when the center-line s of the two equimen t shafts the coul ing onnect s are notarallel and they intersect at an angle. Oset misaignmentcommonl alled arallel oset is when the two shaft center-lines are arallel and the do not intersec the are oset some distane. xial misalignment is caused b changes in theaxial osition of the s has whih mov es the shafts clos er togetheror further aart. This i s commonl caused thermal groth ofthe mahine asing and rotors as the hange beteen ambientand oerating temerature.

It is imortant to reognize that while the equiment lacesthe couling under ombinations of these three tes of mis-alignmnt, the couling itself sees only angular and axial mis-alignment. The exible ortion of the ouling be it a gearmesh or exible elements, sees onl angularl and axiall afull exile coulin g therefore , ne eds more than one exibleelement to meet the oset misalignment criteria and ticalcoulings utilize to laing element s . This ay each elementcan deet angularl and connect the to shafts that are osetmisaligned.

s stated reiousl gear coulings se gear meshe s, whihare loose slines. The are manfactured ith a certain

LAR D EX DS

LLPED D SEETED DS

LTL ONVOLTD D

gure 3 Disc es

amunt of alah between mating male and male t ee th , t hilearan allows the male teeth to move relative to t he maleteeth. he rsult being a gear mesh were the teeth a slie ackand rth to aet axial misalignment and also where te teet han tilt to allow the mesh to aet angular misalient

male tooth atually slies bak an h on its mati femaletooth under misalignment durin each revolution of te c ou-ling, which can e as high as 20,000 times er minte r a hiherrmance couling. The hsical sliding that takes lce e-tween the gear tooth is t he reason r the lubrication reir e-men t the oil or grase allows the teet h to side freely ck anforth and t he oil carries away frictional heat gener te in co -tinuousl lubricated coulings.

Flexible element coulings hsially accmmodate mis-alignment in dirent as however, they all use t he sae aicrncile, which is material eure. The all utilize the ih ere ntability of a material to stretch and bend to so me ex te t ithotreaking. Flexile element oulings therefore, coect toarts of the couling with specically d esigned xi m eersand allow the arts of the coling to moe relati to eachother while the exng member stretches or beds t o accet t herelative motion. It is imortant to recognize that the eximember mus t be strong to transmit the high ower rired adyet m ust also e exible enough to accet the deformtio s fro mmisalignment without breaking and ithout imosin o je ction-able reaction forces on the equim ent .

s stated reiously contored diahragm coui se asingle contored late for the exing me mbers the l te is rel-atively thin and thu s is called a diahragm a ch diahm cabe deforme d much like an oil can lid (efore the das of astic,this deect ion of the outer diameter reatie to the ir i ame -te r is hat occurs when the diahragm is subject to ali-men t ngular misalignmen t ists the oter diamete r, r elatie


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16 EE DN F HE EHEENH B MHNERY Y M

to the inner diameter, and rod ce s a comlex shae on th dia-hragm here it mst stretch one wa at one oint and thenstretch the other ay at 10 degrees . I n beteen these oints ,the diahragm is sbject to a combination of stretching andisting. xial misalignment attemts to ll' the ID and ODaart and, ths, attemts to stretch the diahragm, hich re-slts in a combination of elongation and bending of the dia-hragm role.

Convolted diahragms accommodate misalignment some-what dierently. Th ey se mltile thin lates hich are madeto be wavy from OD to ID They react similarl to the contourediahragm nder misalignment excet that the nfold theavy role f the laes instead o stretching the diahragm.

Disc colings are made of disc acks where the exingmember is alternately bolted to two anges. The relatie motionof the ages is s een by the disc ack as relative movement be-teen the ang connecti ng bolts . The art of the ack betweentwo adjacent bolts is called a li nk an it acts mch like a leafsrng where relatve moveme nt of the bolts rodces stretch-ing and bending of the link. Both angular an axial misalignmentreslt in near l identical dermaton of the link, excet that theanglar misalignment bends the link back and rth as the co-ling makes one comlete reoltion . The is c ack is tyicallmade of many thin indivial dis cs so that it has a low resistanceto deection, in some cases the links can be made with a convo-luted or wavy role to exhibit si milar reslts as the convoluteddiahragm.

I

-I

Fiure 14 Types ofisaimet. a oset b aua c axia

TYPES OF COUPLINGS

Colings can be basically categorized as one of o tes,the rigid coling and the exible oling. Rigid colings areslly sed to connect eqiment that exeriences er smallmisalignments . ince rigd olings also rode the greates t

reaction on conneted eqiment, most alication s reqire thse of exible colings. Flexible colings are sallcategorized as one of for tes ( Figre 1) .

echanically exible lastomeric Flexible elemnt iscellaneosFor the alications being comared , a me chanially exible

gear coling or a exible membrane coling ar most oftenconsidered becase of torqe, misalignment , s ed, and en -vironmental reqirements. The gear coling is a te ofmechanically exible coling and the disc and d iahragm aretyes of exible membrane coling. These t yes of colingshave niqe characteristics that are sitable for th alication sbeing considered.

The general oerating rnciles ofthe for basic categoriesof colin gs are as follows

echaicayexibe coupis In general, th se colingsobtain their exibility om loose tting arts anor rolling orsliding of mating arts . Therere, they sally rire lbr ica-tion nless o ne moving art is made of a materia that s liesits on lbrication needs e. g. , a nylon gear coling) . l so in-clded in this category ar e colings that ses a c obnat ion ofloose tting arts anor rollng or slding, i th so e exre ofmaterial.

Eastomeric cou is: In general, these colings obtaintheir exibility sretching or comressin g a rs ilie nt mat e-rial rubber, lastic, etc. ) om e sliding or rolling ay take lace,but it s us ualy minial.

Fexibe eemet coupis: In general, the exibility ofthese colngs is obtained from the exing of thin discs metal-lic, comosite, etc . ) r diahragms .

nstria

ecanicaL\Fexible

lastoeric

FLexbleLeent

sceLaneos

Fiure 15 Types of Feibe Copis.


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U UP 1

Miseaneous ouings Thes e oulings obtain their exi-bilit from a ombination of the m hanisms desribed above orthrough a unique mehanism .

CLSSIFICTION OF COULINGS

If ouling usage is divided int two ategories , general ose and high erformane, it beomes asier to ategorize thekinds of oulings aailable.

Genera Pupose Couings

!ost liquid transfer ums, material transfer mehanisms,mixers, bloers, ns and th e like run at moderate seed andan hae ver onservativel rated oulings . There are literalldozens of ouling tes and varietie s ometing for a lae inthis eld.

The two omm on mehanial misalignment tes are the gridFigure 16) and the gear te (Figure 17) . The grid te has slotsin eah hub and a sring steel grid hih onnets them . Thisouling must be grease lubriated and is lim ited to relativellow seed aliations .

There are man dierent gear ouling tes in s ervie . Theyall use the rinile of meshing an external gear in an intealger with suient learane in the teeth to ermit some mis

alignment . Crowning of the external teeth llows some inreasein misalignment ithout introduing exessive baklash. Themain variation beteen gear oulings is how the are lubriated and hat kind of seals are used. The original gear ouling, designed b Gustav Fast, has n end ring whih rovidesa reservoir r oil. On some designs the oil sul an be relenished while either running or stoed. More reent designsFgure 1 nororate seals on the hub to retin lubriant.These oulings an be made smaller and less exensi ve and anbe either oil or grease lubriated .

Figure 16 Grid pe Couping.

Flexi ng elem ent ouli ng are available with both m etalli andnonmetalli exures . The nonmetalli exues use rubber, rub-ber like lastis suh as olurethane, and omosite mat erial.The four ongurtion s Fi gure 19) son here are o nl a few ofthe one s avalable but are tial of the nonm etalli exure ou -lings . The sim liit of the design and their eas maintenanemakes these oulings ver attratie for low ower densitaliations.

The m ost om mon exble elemen ouling Figure 20 is theannular dis ouling. The exure ide transmits the torquefrom bolt hole to bolt hole through the annular segmen t. Thenumber of diss an be inreased to arr more torque or d e

Figure 17 Gear Cou ping with Meta i Seas.

Figure 18 Gear Couing with Ring Seas.

reased to imrove exibilit. This te of uling is availablein a varety of ongurations and from dirent ma faturers .The bai onet of the annular dis ouling doe s t res tritits use to low seed aliations but man of the on grationsuse materials hih are of iadequate stren gth to u s at highe rseeds.

Figure 19 Tye s of onmeta i Cou ings.


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148 PROCEEDINGS OF THE EIGHTEENTH TURBO ACHINE RY SYPOSIUM

Figure 20 Disc Tye Cou l ing

HI RFORMANCE COUPLINGS

o general categories f clings have been develoed toserice the high erformace idustry; gear tyes nd exibleelement tyes. These categries can also be labeled as "lubri-cated and non lubricate r dry), since gear coulings re-quire oil or grease lubricatin and exible elemen t tyes requireno lubrication they therefre rn dry. The gear couling cte-gory has many sbgrous to al!O\ r many dirent deigns;however, they are onl variatins on th e same theme , which isthe use of gear teeth in a spline tye me sh to erm the nc-tions required. While gear culings may dir in some designoints , they all are identical in oerting rincial. Dry tyes

however, hae more dier sity; there re two rimary tyes us edin the high ermance ind ustr today: the diahragm tye andthe disc tye Each has its n articular design features andoerating characteristics.

GER COUPLINGS

ec use of the gear coul ing' s domi nance of the low to moder-te oer density alicatins its design was adated and mod-ie during the 50s and 60s to carry more ower at higherseeds. Howeer lubrication became (and still is) the majorroblem. Greases searted nder the centrifugal rce andseals leaked. Cntinuously l ubricted designs (Figure 21) usingthe couled mchines berin g oil avided those roblems andecme the stndard of the i ndustry. These coulings were ro-vided with the external teeth n the hub or ith the externalteeth on the scer in the marine tye (Figure 22). This tyecould be used with integral anges on the mchine shas suchas n shi roulsion turbines and gers. . .hence the name m-rine tye. Reduced moment vers ions (Figure 23) were readilmde vailable for those machi nes requiring them. Lubrictincontinued to be roblem because the coulig itse lf tends toct s a centrifugal lter. n article s in the oi l (es eciall oxida-tion roducts of the addities i n the il) ould be traed in thesmall assages of the tooth clearances or be caught in the builtindam at the dischrge side of the m esh.

This s ludging became su ch a roblem in the 1970s that manygear couling designers rem ed the dm and/or required neltered oil ve micron of sucient o to ush out the arti-cles. Ths x hls but it des n't eliminae the rolem.

The m st common mode of failure for a gear cou ling is ear.

It is one of the mos comm on and sim lest cou lings us ed toda.Due to the numb er of aribles tht cn aect its s ucce ssful o-eration, it is usully dicult to design and evaluate.

gure 2. Cntinuously Lbricated Gear Coupigs

Figure 22 arine Style Gear Couling.

Figure 23 Reduced Moment Gear Couling.

A gear culing has its most s ignicant eec t t nly n it -self, but o n sst em cmonents from the forcs mm etsgenerated when it sl ides andor misaligns. he a ear c lingaccommodates the sha oat frm thermal grth hll d eec-tion shock, etc. axial forces react back ont the thr st bering sand other equiment. When misaligned, a ge ar pling illroduce a bending moment that will load eipe t shafts

bearings, nd other system comonents. Both t he aial rce sand bending moments are signicantly acte y the lbrica-tion and the cecient offriction between the atig gea r teet hmembers.

Vrious culing manufacturers use the follig ty ical al-ues om te st data for the coe cient of frictio n:

Sealed lubricated gear culings: 1 = 0 .05

Contin uous lubricated gear coulings: = 0.075

Vlues of coecient of friction higher than th e ae ca n eexerienced , although if they are resent r ay p erid ft ime the couling is n o longer exible which would re tha likelyreciitate the ilure of one of its wn comonet s r s me c-

nent of the couling equiment. Ifa coulig is echanicallylocked due t sludge or wear, the rces cl e incresedseen t o eight times those normally exected.

There is till muc h discussion of ho lrge a al e t se fra sat ctr hen des ignig a sys te or eve n a gar ci.Due to the high reliabilit necessary for turb ach ine ry apli-cations, the merican Petroleum Institute specicatins re-quire thrust bearings to be designed for the mai m gear cu-ling thrus t lad with the cons eratie coeici et f friti f 0.25 for continuu s oerating conditions.

FLEXIBLE ELEMENT COUPLING

Flexible element culing use was limited thr gh th e 1940sto low torque, low seed alictions here ly limitedamounts of misalignment were required. In t h lt e 1940s, theaearnce of the small gas turbine roduced th e eed fr th ethin contoured diahrgm, hich sa usage i aircr aft lica-tions. The rogress nd ccetnce of this couli i idus trialand mrine alications was greatl hindered b the i ability taccommodate high misalignment and lrge xil em ents.

For man ears, gear coulings hae een s e st em t r-bines gas turbines comressors and us. he th e hrse -oer, seeds, and erating teeratures icreased maroblems ith gear coulings develoed. The eed fr lermoments , forces, and noise characteristics has p sh ed th e ad-anced deYelment and usge of exible mer e cli nsin thousands of lications. cause of this deelpe tech!


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50 E ED F THE EHTEETH TB HE Y Y

Figue 2 Piloted Cotoud ihgm Coulig

gue 28 Reduced omet Cotoued Dihrgm Coulig

ultile Covoluted Dihgm CouligThe multile cnvluted diahragm culing was rst ntr-

duced in 1971 . The rst design intrduced was a culing witha large rati Figure 29 between OD and ID clam diameters t ride high misalignment caacity and lw st iess .

r r

Figue 29 Dihgm Pck Prole ) P seies b) R series

The frce alied t the ID the clam ring blts is sucientt cause the ack t act as ne slid un it in the transmis sion ftrque. The ack transmits trque t te slined adatertrugh a mar diameter interference t sline .

The secnd design intrduced 190) is cnstructed with areduced rati see Figure 9) between OD and ID clam i

ameters in rder t btter accmmdate the red ed entnguratin . The ack at the I D is fused t get r \it a fllenetratin electrn beam weld which makes te sline reaa slid unit. This increases the shear diameter ad therefre the trque caacity. Trque is transmitted fr t ac ba ne itch sline hile bending mments ar sisted clam nut. Thus the welded rtin f the ack i t subetedt reersing stresses imsed by rtain and isalignent

Flexure takes lace nl in the cnluted ar f the diahrags which is n t aected by the el d .The heart f the m ultile cnvluted diahra cu ling i

the stainless ste el diahragm ack (Figure 30 )Th ack cnitf several thin cnluted diahragms searatd by insiddiameter ller rings and segmented utside diete llerThese are sandwiched between thick end lates t gie rigid itt the ack. The cnvlutin and its unrlling acti n usall results in large axial caacity fr these culings . Th ultile cnluted diahragm ack has a linear stines s axil tine ss .

gue 30. ultile Cvluted Dihgm P.

P SEIES (IG PEFORMANCE) (Figure 1

Diahragm rle erm its large axial and anglar de ecti nwith lw stines s . Diahragm ack is ightly clad at the causing it t act as a slid unit in the transmi ssi f trqu e .

Figue 31 HP Series (high peformce)

SERIES (EDUCED MOMENT Fire 32) reduced ati ac in a high erfrmanc red e d men t

design culing rides increased bre n d t e caacitith lw verhun mme nt. Diaragm ack is f ed tg et erat the ID using a full netratin electrn beam ld.


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1 1

ck d

-

- -

h cl c DhckFigure 3. RM Series (redu ced moment

RR SERIES REDUCED RTIO) (Fe 33The redu ced ratio ack from the rm s erie s in a high erform-

ance h conguration roduces a light high torque caacitycouling.

t

w

gure 33. R Series (educed ratio)

DISC COUPLINGS

Originally designed in the early 1900s isc coulings haebeen adated r the strenuous demands of mode high r-rmance equiment and re frequently used r nonlubricatecouling alications . The se tyes of coulings use disc acksthat hae a series of axial holes th rough which the ack is alter-nately bolted to two serate anges; torque is transmitted mone ange to the other between the bolts and through a tensileload on the discs . Flxibility is obtained from the deection ofte ack and aries with the length between ajacent bolts; in-creasing the number of bolts raises the torque caaci y and de-crases the exiility of the couling; hig h erformance desig nsgenerally us e si x or eight link desi gns for the roer balance be-tween torque and msalignment caacity.

Mos t disc coulings use many thin discs to make one ack in-stead of one thick disc r increase exibility and minimal reac-tion forces; the ractical thickness of the indiidal disc rangesfrom 0.00 in to 0.025 in. High eormance coulings haediscs made of corrosion resistant steels 300 series stainless P Hstainless o r high strength nickel alloys. n disc otions areaailable including circular hex scalloed and segmenteddiscs for dierent st ress and exibilit atterns; the ost ou-lar for high seed serice are the hex and scalloed designssince the ossess the best serice characteristics.

Four link d iscs are not u sed for high eomance coulings due to the uneen seed uctuations th roduce similar tojonts) s ix link desigs are used for higher misalignment s orhigh axial groth alications. ight link dis cs roide highertorque caacit ith exibilit to accommodate most installa

tions while ten links are used for high ower require ents ithminimal misalignment needs Figure 3).

ecause the disc acks are made of man s man facture sroide ack subassemblies. ome isc acks are ftory i-stalled on the couling while others are s ulie ith ilotrings for installation in the eld . One er im ortant ftor thtinuences couling life is t he roer ten sioning of the i sc ackfasteners . The fasteners can be installed in the eld t thi s re-

uires accurate bolt torque equiment and roceres. Forthese reasons some couling manufacturers install an torquethe disc ack fasteners at their factory to assure the rrec t le elof bolt tension.

LNK 8 LNK

gure 34 Disc/Link Shaes

High ermance disc coulings hae isalignmen t nd axialgrowth caabilities equal to other d ry tyes and are se nall categories of equiment including gas turbines ith highthermal growth. They are aailable in a number of stles thetwo redominant congurations are the reduced ment andthe marine. The marine style Figure 35 and 36) eries itsname from the marine style gear couling and it sim l ntainsthe exible membrane on the center ortion ofthe ling. rigid hub is mounte d to the equimen t sha and the is c ackis attache to the enter sacer where it can be com let ely re-moed and droed out. The rduced moment style ntainsthe exible member on the hub mounted to the equie nt shaFigure 37) This moes the disc ack and therere the eec-

ti couling center of graity closer to the machine earingwhich reuces the oerhung moment of the coulin n tesha.

Figure 35 arine Style isc oulins.

COUPLIG LIFE

Gear and exible elements exhibit iel iergethilo sohi es e dtermining oerating life. Gear ins


12/24

152 EE D F HE EHEE H UB MHEY YU

gr 7 Rdcd Mont Dc opng

PRBR

are mechanicall exible and deend uon the relative slidingmotion of the gear mesh to accommodate misalignment, thustheir service li is deendent on tooth condition more thatanthing else. If a gear couling is roerl lubricated andaligned, it ill give ears of troublefree s ervice examles of

high errmance gear coulngs running n excess of twentears are not uncommon . Hoeer, a gear couling is denitelsubject to wear om the slding otion of the teeth and it ismore co mmon t o have to relace a gear couling aer ten earsservic e , s ome articlarl diicult alcations can even shortenthe life to to ears. Distres s shos u in two tical as; thetooth contact faces become damaged, or the tooth tis are orn .

The faces of the tee th can be itted as a resu lt of oor lubrica-tion o r from igh misalignment, a articular te of itting dam-age is called wormtracking" and is a result of extremel highsliding elocit of the te eth combined Vith marginal lubrication.Normal wear tends to slolv erode the faces of the teeth untilthe hardened case of the nit�ided teeth is remoed. The coe-cient of friction at the teeth increases and the couling becomesmore resistant to motion unde r misalignment; the bending mo-ment 01 te uiment sha increases and the couling resitssling une xial misaigen t . In extreme cases, the cou-ling is irtual locked u" and will not free s lide t accom-mo date any misalignment. These conditios can us uall benoticed with equimen t vibration monitors , and tal man-ifest themseles as a stron 2 X oerating see d signal , iccorrelates to the gear tooth sliding back and forth tice durineach couling revolution . Unfortunate l, a good qantitatiemeaure of toot distres s does not exist, but a sharp e e at in-sp ection can discen tooth condition reaily.

The couling comonents mus t be maintained in some radialos ition during o eration to ensure dnamic balance . I f a artis allo\ed to shift raiall, it il roduce u nbalance, w hich can

be extreme at the oerating seed of most t urbo hin er. Forthis reason, the gear meshes of a gear ouling r ilotd; t htis of one set of teeth are tightl tted to the root s of the atingset. Oer time, the slight ilot clearance of th tth cn in -crease due to wear and the couling unbalan n increase .Once again, this condition can sall be signal ith vibrationmonitors , which wil be see n as a slol increasin g 1 X oeratingseed signal related to unbalan. Often, the oling nba-

lance can be swamed b rotor unbalance , so it is alas agood idea to check the tooth clearance during aintenancturns.

FAILUE MODE FO GEA COUPI

For gear coulings, the most co mon te of filre is de t otooth ear and disress . Tooth distress is mos t coo nl causedb

Inadequate lubrication Figure 38).

Imroer tooth contact Figre 39 . In this se , th e cou-ling ran close to a torsional critical, and the cli loa d cusedlocalized tooth distress onl on t hose teeth load d.

rm trackingcold ow or elding occurs o re eqen tlon continuous lubed coulings This occurs near the end of the

teeth when misalgnment aroaches the design limit of thcron, and the lubrication lm breaks down and us es m etal-tometal contact. High localzed tooth loading or l bricant de-terioration can cause this te ofilue as des crie d i n iroertooth contact Figure 0).

ludge bildu can cause ile of almost n ss te m com -onent such as shas or bearings Figure 1 l de also illcollect corrosive residue, which can corrode coling arts andact as a source of crack initiations r a tiguero ted ilrof a art.

Fgur 8 a r Toot Fa naqat bn

DESGN PNCIS FOFLEXIBLE ELE:ENT COUPL

Flexible e lemen couplings are not mechacll exible likegea ouplings, they operate through eue of teril, thsthev ebit er dierent behaior and their srice life is amu�h diernt penomenon . First, the are dsigned to oer-ate within the fatigue life of the ex ng material. Threfore, thehave an innite l if f orated within their red cpaitie s . Allexible element coupling desi gns have been sbjct to de taldst ress analysis and te endurance limt f the coling has bnpinstakingl determined b co mp rehnsive t st ing . Fl exible


13/24

U 1 U 13

gu . a Tot h u (o too th ontat).

Fg 4 a Toot Fa wa takngodowj.

eleme oulg mufurers use s d o deerme lfemrgs su s Good dgrs d o esbls sfeoerg lms of oulgs ltug dry oulgs ve obee used s log s ger oulgs g erfome l-os e resuls s f e ded y ll ou lveer ger ouerrs osderble mrg e mo ro o be re of s e fgue lfe of dr oulg smos ueed b e gulr mslge of e exblemember s gulr d os mslgnme o e eu

Fgu 4 Sudgd u a Coung

e) sce oly s mslgme usuly rodues te lr-g sress r gue Flexble eleme oulgs o seed o ser remg l s e e exble rs llo so y dsress ul ey ully brek g . Ho-

ever mos coulgs o some redud feures d elkelood of fgue flue s exremely remoe .om e of e sresse s resulg from e ex eleme ec

re cuus durg he ere erod of ero d es ere ermed sedy se. e oer d soe oft e sre-ses o ol vry bu go roug comlee reversls d ur g erevoluo. Tese re ermed lerg.

Flly e me sress d e lerg sress rsulgom bedg of e ex eleme be loed o d edGoodm le for vrous mslgmes d ol oul g xldsleme s sg yl Goodm equo vlu e fhe des g for be luled. Te resuls re s o Fg-ure 2

Fg 42 Gooda n Dag


14/24

154 PCEEDN F THE EHTEENTH TBCHNEY YP

COUPLING EFFECT ON S YSTE

Coulings aec heir conneced machines in hree secicareas

isalignme n mo men s reacion forces and axial forces Criical seeds nbalance

OMENTS, REACTION, AND AXIAL FORCESISALIGNMENT OMENTS

The hysical reacion o ransm iing orque hrough a mis-alignmen agle cause s a reacion mome n on he wo connecedmachines. This mo men varies direcly wih he orque and heangle and is abou 0 . 2 erce n of he orque in a yical insalla-ion. This mo men is r esen i al ougs o ny kid anacs in a lane a righ angles o he lane conaining hemachine shaf and sacer ce nerlines .

echanical alignmen coulings such as he gear and gridye aly a bending m ome n on he machines ha is a ncionof he ransmied orque. Wih gear coulings his momencomes om h e s hi of he load conac on he eeh away fromhe cene r of he mesh . This o cener loading will yically con-ribue a momen of abou en ercen of he ransmied

orqueddiionally gear co uling eeh m us slde agains fricionwhen misaligned . The mom en from his fricion is roorionalo orque and he coe cien of icion and yica is abou veo en ercen of ransmi ed orque wih good lubricaion andcan easily reach 25 erc en wih marginal lubricaion . The veco-rial combinaion of hes e mo men s o a gear couling is i-cally abou 13 ercen of he ransmi ed orque r a well lubri-ced couling.

Flexible elemen coulings such as he disc and diahragmye imose a bending mo men on he machines ha is roor-ional o misalignmen bu is indeen den of he ransmi ed or-que. This bending momen varies wih he bending siess ofhe couling hich ill dir ih he ye of exible elem enused in he cou ling. icaly however a exible elemen cou-ling would imos e a vecorially combined momen of wo er-cen of he dgn orque on he conneced machines .

RACTIO FORCES

These momens mus be reaced b he conneced machines.The reacion forces are se en a he bearings an d will also endo bo he m achine shafs elasically. There are wo se s of forcesfor each machin e .

The larger of hese reacion forces has a magniude equal ohe vecorial s um of he mom en s a each ariculaing oin of acouling divided by he disance beween he ariculaingoins . This radial force is he same on each of he connec edmachines and acs a each of he ariculaing oins of hecouling.

The smaller of h ese recion forces has a magniude equa ohe ecorial sum ofhe mom ens from he coulings a each endof a machine roor divided by he di sance beeen he bear-ings. This force acs direcly a he bearing.

These m isalignmen m omen s and reacion forces aear asseady sae loads o he nonroaing obserer. H oweer heac as cyclic load s on he roain g shafs . If a shaf has annonuniform exural siness such as from keas for cou-lings or for urbine or comress or disks hes e cyclic loads candirecl cause vibraion.

XIAL FORCES

Gear coulings imose an axial foce on he connecedmachines hen e disance beween he machines changes

such as from hermal groh. Th is force is di cly roor ioalo he ransmied orque and he coecien ffricion and in-ersely roorional o he gea r ooh ich di meer.

F =TR

Wih good lubricaion on moderaely loadd gear coulingshis force (in ounds) is numericall abou e ercen of hransmied orque (his assumes R = 1 in) . Ti s frce can easilclimb o en ercen wih marginal lubricai and 25 erceih locku.

Flexible elemen coulings such as he d is c d diahragye imose an axia force on he coe d machin esheneer he couling is sreched or com ss ed from i s frlengh. This force is roorional o he amn of deeciosrech or comress) and he exural s is s o he ye adsize of exible elemen couling. T he axial e is indeend eof ransmied orque. This axial rce is abo 0 5 ercen fr yical alicaion.

If he axial moion of he machines is kno or is reasonalyaccuraely rediced he exible elemen cing can be i-

saled wih a redeermined resrech (r romressio) such ha he deecin becomes near zer a he oeraigcondiion.

For nely de signed machines keeing he xil force low adredicable alos a smaller and lower drag s bearing o used . On exising machines keeing h e axil rce lo helsreven excessive wear on he hrus bearig sand vibraiofrom inermien unloading of he hrus be ring .

COPARISON BETWEEN GEAR CPINGSAND FLEXIBLE EEMENT OUPIGS

comarison ofload and accessory drive xibl e eleme n dgear coulings is lis ed in Figure 43 r a yical indusrial gsurbine. Couling diameer eigh orque ondiions bend-in g momen and axial rce are lise d.

CTJNO CONTIN0 NT! ENiNG

0. Jf T AX F W : A T NUR EN T ON E {) W N D � AVEL ONTN S A N HEN ONTN( S l N . H E$1 T O N

B N-

E G£ OP IN (p o S 12 . 9 8, " ! 25 9 E c5 IN p " 75 0 1 , 45i t

DAA A 0Y O N 1 7 liO C ± 4 EA OA O N 6 4 3 ,6 %, O O < Z 4 3 2 ± \Q_

D AD O N 694 · 3 u 4 A t I N N f N I O A m !

Fg 4 oaron ar ong to Etong

The forces and m ome ns are calculae d r diere n co f-ciens of fricion o demons rae he i mac f his ariaion frgear coulings. The coecien offricion ill r h he o hdesig e and quani oflube he es o arial and o hnish. For a exible elemen couling he en s and forcsare redicable and are simly relaed o h siness of emeallic elemen . lhough a ear couling ill icall ha asmaller diamee r and a ligher eigh for e high axial rlrequiremen alicains he bending mom imos ed b gear couling on he ssem is sill u o e im s higher hhe equialen diahragm couling. The axil frce imo sed he gear couling can be equialen o he ible eleme c -lin g deenden uon he coecien offrici . Und er eak que condiions fie o en imes he normal erai ng orq) he axial force can be nine imes greaer for he gear coulig


15/24

L 1 N CPLN 55

d t e ed momet 5 tes grter t cmpreexe eemet cupg

cuts s ed te rereme ts f PI sp eccts(cecet f frct eus 5 r e cmpre Fgure 3Te mpct f tese mmets d frces sstem desg see mre sgct d c reure rger ss, ergs,tcer ges, etc, t te ger cupg

CRITICL SPEEDSI ddt t msgmet frces, cupgs s terct

t te mces ctg ter trs d lter crtcspeeds, d fr exe eemet cpgs, trdcg x tur freuec (Ts x tur freuec s ds cuss edfter te sect ce

TORSIONL CRITCL SPEED

Te trs crtc speeds f mce sstem re deter-me d te sze f te ert ees te mces d tetrs sprg rte f te sfts d cupgs cectg temFgure 44

g 44 Machn' Inta and opng St.

Te trs sprg rte f cupgs seected fr e de-sed mces fte must e mded frm "stdrd rder t sft trs crtc speed frm te pertspeed re

e repcg exstg cupg t deret tpe fcupg, t s geer ecessr t ve te e cupmtc te trs sprg rte f te d cupg Ts s remprtt t mutd mcer tr ctg mtrsd ger wc eerte trs exctt It s es s mprttt smpe t d ture cmpress r trs c e t-te trsl exctt

Te tr s sprg rte f mst cups c e m ded cg te dmeter r egt f te ceter spcer

tues (Fgure 45

LTERL CRITICL SPEED

Te ter crt c spe e f mce c e ecte d teegt ceter f grvt ct f te cupl g

Te cser t e pertg spee f mce s t ts tercrtc speed, te mre sestve e ts vrt resp set uce (Fure 46 Fr rust mces t "rdsfts , pertg el e ter rst ter crtc spee d su cs mtrs d pressu re pumps, see Fgure 47 Ts s t sgct prlem Heer, fr ess "rust mces scs m stem tures , mst cetrfug cmpressr s d m

Fg 45 Toona Stn Modd b hangn STb.

V I B R A T O N E S P E E S Y

P

E

C R LS P E E D

g 46 Sbctca Vbato n Rpon vs Opatng d.

gers te egt f ev cupg des ct te crtcspeed d reduce t sucetl t ecrc up te ert gspee rge ( Fue 47

I ddt, mces t g sft verg (Fg re 4 ,r veru eel (Fure 49, r t egt, lght

Fg 47 Machn Wth "Rgd and "Not o Rgd S ft.

Fg 48 Machn th Long Ohang.


16/24

56 PCEE DN F THE E HTEENTH TB CHNEY YP

Fr 49 Mach Wth Ovrhg

lded ger p (gure 5 , c e dversel cted tewegt f ev cuplg

Furtermre, m mces re desged wt "eless d re ted ed t perte t speeds ve ter rst del ter secd lterl crtcl speed (Fgure 5 pcl

mces re cmpressrs dlg lgt mleculr wegtgse suc drge r " gs

gr 5 Lght Loadd a r o.

gr 51. Mac h Wth "Fb Sh at.

Tese mce re geerll ute sestve t ulecused vrt d ts sestvt s ggrvted de-crese f te se cd lterl rtcl speed trd te pe rtgrge (Fgure 5 t tese mces , t l te mgtude

SENS ITIVITY � 1S 2ND

,

, : • ,

I

\

'

�

Fgr 5 Srrtca brato Ro v OratngSd.

f te egt f te cuplg , ut te lct f tht eght f-fects te secd crtcl Fgure 53

Here te "mmet (egt tes dstce t th e de t ,c s e t r er te erg s te pr er t f te c u-plg c ects t e secd lterl crtcl

uplg mufcturers c prde specl lhteght, re-duced mmet cuplg fr tese ce he e culgreduce te "mmet sftg te ceter f rtcult clser

t te mce d ts de, tu s sftg the t t hchte egt f te spcer prt f te cupl pers t ctup te mce sft

W M

Fgr 5 og ght to Nod ot Dtac.

UNBLNC

Fr te ress c ve just b n dued, te u

lce f te cuplg d mce rtr ss l ve s eru eects t vrt f te m cer r cermucturers lce te rtrs ter wthut the cuplg plce r wt prt f te uplg d m e t egtsmultr plte plce T e ltter teue h elpful c m-pes tg fr te wegt eect f uplg " e le rt r(Fgure 54

Te cuplg mufcturer lce te cu l t sm ult ete mce sft mutg Ts de ture s, md rel,r dcted prts (Fgure 55

mjr surce f ptetl ule f th e ul g/rtr -seml s sum f te mutg errrs trc the d ere eetwee te mutg r ltg f te ul fr lccrrect t t ftr d te mutg f the me cuplg te rtr

FCTORY BLNCING

Te rt edt f t PI tdrd 67 " e clPurps ulgs fr Rer erve, reg drt"scls fr fctr lg d e cre etete l

COPONENT BLNCE

e "cl cmp te ccept f lc e f thcmpets f te cuplg depedetl te l u-lce crrect step Ts tecu depe u t ccu-rc d t f te sseml lctg feture f thee cm


17/24

TTL 1 N CPLN 5

U U

gu 54 Rotor Wt a ht uator

gur 55 oupng on a anng Mand

M

es eve ed ssem ( es e upgmufurer mrks e mesur ed eer g sps s e mpes ssemed erg "gsps s e mp es e s semed erg"g sps 10 degrees ufpse mme e ue ee f er errrs

me dves f s eue re: Te mpe e erged u ds urg

med ssem Te mes ssemed wu er fr

gg mmrs T pe ue resug frm ssem e

r errrs ere e mpes s wrse ep ue resu g frm e er errrs ere mug e upg e m rr

Te ures frm mp e e rre ess

mpe d rdue ess u errr

SSEBLY BNCE

Te er s mps e ep f g empee upg ssem mpe s rs eds mpe d e ss emed e upg se ed s ssem Ts eue resus med sse m ur es f e g feureseurzed

me dvnges s eue re: Te pe ue resug frm ssem e

r errs s rreed e fr

Te upg s mmrked d e ress e e fere dsssem e sme s fr ed

ClfPONENT BLNCE DSSEMBLY CHECK BLNCE

Ts mprm se eee e "ss er e dge f erge frm e mpe e eue dvge f m g e pe ue frmssem feure ure kw u s eue sss f dg e mpe e rre fed ssemg e upg mre r re dmesur g e ue f e ss em N u rre s de e ss ud e mesure u e e g e mpe e mus e ree e ssem ek ree

ca rob n actor aancng

e ger upgs re e ss m e r ss em eked) e dmeer ver e ps f e eer ee sef vers ed prve gd p e r e eree e seeve Afer e g per er szed s re ved prvde e eess r e r e fr per Tu e ssem ed d e dem

sed fer e upg s devered r ger upge s red red e ed andr: Hsr ugs ve ee mu e d

rd mdre g e upg d prve urs re er e upg g surfe e ures r ge ps Hever r rge r g gs emdre eg uses ver sg errrs ddl upgs sm dmeer sper ues e mdres re mer deue rgde e upg

Mandr baancng Terere e ee f er rgdg upg (usu ee eeme e deveped ee rg e upg jur deers re pr f e upg r mu e ss mpe d g er mdre

FIELD BLNCINGTrm e upg/rr ss em e her r se s e m s mpee w remve ue fre upg mug errrs Ts resu e esperg vr eves I s me sum d e esver du d rge me se per s erdepede er mes e p

rd f u rm g mes he e d B esure u re rreg fr upg mu g errr s mskg serus mfu er e f hemes

pca rb n d aancng

Beuse ger upgs deped up e sef eergrerss f e ge r ee fr er ger

upg sper ke ere ps fer e resrTs rdm ge resu ver s emesured ue mu d ge

IL NTURL FREQUENCY

I e rdu e se RITIAL s m eed ee eeme upgs e ur freue h ger upgs d ve T ur freue (ANF ) s reed s f ere r e e d

Te N resus frm pss f supprg (heeg f e sper se f e upg eee sprgs (e upg ee eeme s Fgure 56


18/24

15 PCEE DN F THE EHTEENTH TBMCHNEY YMP

Fge 56 ong Sace M ete en To ng

A cupg rte t ts A NF f t s excted tecected mces Mere rttg t te sme RPM s teNF t cuse cupg t rte Atug e c mke cupg rte t ts A NF rtr rt mce, s t es t excte t eug t get rge mptudes ecusef sme ert ex st mst f te exure stesss ( smesm d sme er rge exe eemet cupgse ee pertg fr ers t speed s t r e r t ter NFut ed prems t cupgs ter cectedmces e ee trced t cup g rtg t ts ANF

Te PI tdrd 671 reures tt cupgs e desgedsuc tt te A NF " s t f t t e percet f f teg

A speed t te rge m te mmum le

speed t te mxmum ctuus speed tmes speed t te e speed rge A ter speed r exctg freuec speced te

purcserTe purpse fddg te A NF t t tmes pertg

speed s t preet rt ccurrg tse ces cgeerte 2X x exctt r exmpe m rpedtrust ruer

Tere re ccss e cupg ct e d esged tplce te NF eter el r l e te rdde speed rges I tse cses ere te ANF ecrces prt f te frdde rge , te cupg d esger m e et m ke use f te cge A NF wt xl deect r crprte sme tpe f dmpg f te cupg t e te ercet l ccur t seldm used pertg speed suc

s durg strtup trset (F gure 57)

AXAL ID E E C T N

X

N S E g 5. Deected Aa Nat Fqenc v s Speed

ELECTIONFexe cupgs re t prt f eupme t tr -

frtute, m sste m des gers tret tem s f te ere ter pee f rdre sted f eret cmp-et f te rttg eupmet Te mut f cre spet seectg cug d determg hO t tercts t ss-em g g y twrd mmzg p ssbe prbems It s ctuly urprsg cst equpmet dtme cudfe ve ee emted prper ttet durg te seec- prcess

I sme cses, te seect prcess m tke y tte tmed s sed st experece; O\eer, spstcted sys

tes te prcss m reue cmpex ccut s, mputemdeg, d pss ee testg sste de sger r userjus t ct put cupg t tr t te pe tt t rk te cupg mus t e cpte t t e tr res f perfrmce upgs re ced u t trstper d ccmmdte structur mt d t herm cgef eupmet terefre cmpete kedge te mpse dds d memets s reured I ddt, te cupg

tercts t te rtrdmcs f te eupme t s te p ertet eects f te cupg must e csdered te trss e ts s srtcged, cupg e c e reduced r cs t fure cud ccur

Tere re tree res were cupg seect cud tkepce t te user, t te dretr, M , d t t e cugmufcturer Ad ter e re t geer seect stces fr e tr r fr retrt f exst g tr eg rdess teprtculr uces f se ect, tere re usu fur stestke t ssure prper s eect f cupg fr c rtc r teupmet

Te cupg seectr reews te t reuremets dselects te tpe f cupg tt est suts te sstem

Te cupg seectr supes te cug mufcturer(s wt l te pert et frmt ut t e ppct ,

s tt te cupg c e prper szed, desged, d ufctured t meet te reuremets Te cupg mucturer suppes frm t t te cu

plg seectr ut te cupg crcterstcs , su c s egt ,trl stess etc , s tt "sstem ss c e de

Te cupg seectr reews te resuts f te sstess t ssure cmptt d reuests cges weecessr

Ntur, ts s t te prcess t use r smpe trpump ppct, ut t s used r crtc rs d fte es m terte des gs etee te cug seectr dmucturer t "tue te crcterstcs f cu pg t t prtculr ppct

NEW APPLICION

e st mjrt f e eupmet s w eg suefrm te M t exe eemet cupgs e ewpece f eupmet s e g purcsed, te tr EM des temjrt f te cupg ree Te use r tc de sgtes ccepte cupg edrs, weter ger r exeemet tpe s desred, d f PI 671 r ter specctsre reured Heer, ts sud t ree te use r rte prcess e sud ree te seect t c rm tt t edesg meet s s prtcur pertg d mtece reur emets er , e e t "e t e cup g fte rstt

Te tr M m ust frwrd te fg rm t t t ecupg mufcturer fr prper seec t :

Hoe oe rm, mxmum ctuus, pek Speedrm, mx ctuus, trp, setmes true,

c e supped sce t cmes H P d seed , s, uusu cdts, suc s srt crcuts r sur ges

onecton to eqpent sft r ge sze, keed rkeess druc

Saft epato Angar a nd offet ag e t Aa paceent patcar for d cpng opng a/eatc taton ct,

trs stes s, x frce, et Sa ce o eneope tato


19/24

TTL N CPL 5

T cup mucr s upes te g dt e reie f te reuiremet s:

upi size d tp (reduce mmet , ste, etc Mssestic dt eit, , trsi stiess, ter

critic speed , ierti (2), xi rce/deecti, ur m-met, etc

ime si dtTe tri sis is te perfrmed d reemet f te

cupi des ig is de if prems exist i extreme cses tecupi must e desied fr sc rtc t meet riid reuire-met s) Te cupi mufcture prvids eer rre-met dri d ter dcumets , ic ct te cupidesig dt fr revie te user d 0E M

RETROFIT

Tere re t mjr diereces frm te ve prcedure ifte cupi is retrt ppicti ) tere is exsti cu-pi ei repced i te euipme t tri , 2) fte preistri sis des t exist r te euipmet E! is t i-ved i te tri sis Tis situti mst fte cmesut e te user is it eest i repci ger cupisit exie eeme t cupi t te dvte f te ee-ts f dr cupi Te rst mjr ues tis is sud te

cup i e repced t ? Tere re fur cmpei res st t ce cupi desis: Satfactor oraton Te fmus si if it i't re ,dt x it ppies ere As s te er cup is prvid-i stisfctr service, tere m t e re eed t cgeit; see res 42 Mantnanc Fexie eemet cupigs reuire ess c-tiuus mitece ecuse te d't reuire urici;ever, te usu reuire iger eve f si t prperist d te must e treted it cre e rig rudtem er cupigs re ess ses itive d ccept mre use3 Rtrctv achn Tere m t e eu spce vi-e t t te exie eemet cupig i r t e tri dmicsm reuire cupi it imited crcteristics 4 Econoc. It is recmmeded tt tri sis e uder-

te e ci frm er t exie eeme t cupis tme sure te rtrdmics re t derse ected (if tcupi dt ct e m tced) Te cst f tis m fr ex-ceed te pteti ue f exie eemet cupig iservice)

If tese re ccepte, te exie eeme t cupig cprvide sme direct eets, suc s uricti, er u-ce d pertig rces , d ife N is te es t t esure tt te exie eemet cupi c estseected t t te tri? If te user returs t te euipmetE M , te prcess fs c t tt f te e euipmet seec-ti d te EM d te cupi mufcturer d ms f ter it iput frm te use r tri perti experiece) m e users prefer t use iuse experts r csutts t per-frm te tri sis, i ic cse te user i eed t e

ver cse ivved t p rvide dt d t reie te seectiprcess Bt prcesses ve merit d t ve prvided versuccessfu retrts; te prcess fs tis eer prcedure:

tte mpt t mtc te er cpi dt it te e ex-ie eeme t cupi cec tis, te cupi mufctueri eed te fi ifrmti:

dri f te exis t cupi ei repce, iteit, R2, s, trsi stiess, sft epti d sftcecis (tis sud e due ceced, si


20/24

1 CEED N F THE HTEENTH TRBMCHNERY YMM

s re ge h rele d scus s f he jr p fech s flls

e 1 GNERLS 2 ) BS ES GNSec 3 ERLS O CNSRUCONSec 4 NUURNG QULY SCON

SN N D PRE ON FOR SH ENSec 5) G URNE N RNYSec ) ENO R'S pped ) COPLNG SHEESpped B RL SPECFCONSpped C) CO UPNG URSpped RESL EN OU LNSpped E) COU PLG PERSpped F PER GES Secd d fP 1 h s ee lzed r relese

le 1989; hver l prel r fr l-le pr se cs 1 h re sujec chgee geerll prse ed here pprpre he llgdscus

GENER

he sc frerk f uders dg r he specc

cludg he sc pe f pplc cc d leres , ddes d rereces re prese ed hs sec -pr see d e h s c s h cuplg rerse rered he eup OE r prpr pplc sec d he r f s e verlked; ulle (• he rg rers dec s he cuplg purchser ul-leed s re fe pr d re fe erlked chrures her r su her hce r h e

BSIC DESIG

The servce crs used r slecg cuplgs ege hs se c u rue cpc f he cuplgus e 15 perce f specfd rse ru cpc use 1 15 perce d s lge cpc us e 125 perc

currg suleusl h 25 perce f l dslce- hs re f h ecc hs geered re dsc us-s h ll hers ced, prrl due he 1 5 secefcr he dscuss f he servce fc ces e s-ec f eup rs rue cds he h e cu-plg ll see hghr rl perg rue Eupeperrs k h u usul ee s ls ccur d cu-plg ll rde he grees s rg he heseees hppe uplg ufcurers k h here res rgs h cuplg des d he re reluc elc cupl h ll v rszed fr h pplc hhc ls h perce f he che r

he ppl f he 15 fe cr s us d eSecd d f P 1 c s re del u he use fhe servce cr he susu f ler fcrs hereche per ll u ler h 1 25 ere

he sselsc reuree s (eg CG f he cuplg pre-clude s use

Detailed requirements for bores ad keways ae giYen,hich is rinforced in the ins tallation section of this presenta-ti on ; the need or high qualit hub to shaft connect ions is slf-vident. Other detailed reuirements ae given ith spcicfr ech cuplg pe

nac ba anng s he r r f Sec 2 hch d-scres he cuses f ulce d s hree recededlce prcedures

oonnt Baanc Cuplg cps re ddulllced d suppld h prcedue llws u fr

dm fr prs erchge u de e ss ele dcuplg lce

oonnt Ba anc and b hck uplcpes re ddull lced he ssle cplee cuplg fr check fhe erl ssl lcehs prcedure lls fr pr erchge es ceckf he full ssel, u de crec f r lce f he s sl

oonnt Baac and Ab Baa c l crrec s de he cupl s pde mo nt aa ncand Ab ck Baanc le s sl ulce hle e cuplg s he lce hs prhs he dec echge ces, e e recuplg s "red s ssel, u hs rr s feused prvde l cuplg ulce fr s se hghspeed rrs

The s E d f 1 ued he c prcse chse e f hes hree prcures chce sfe lled he cuplg ufcurer er he l-ce che he Secd d f P 1 cll de-fuls oonnt Baanc and Ab ck Baancoponnt Ba an a nd Ab Ba anc s le e spe d he purchsers dscre he lce lcs re hese h eds, ecep he ecd E ludes l r ss ecerc h lg helc che, hch 5 r ssel chcks d 5 r crrec lerce (5 d 50 ches , re-spevl) lc mche Sntvt he Frsd hs ee reved he Secd d re-plce h prcedur here h cupl s ssseleer lce d resseled he lce e chech h cuplg ssel ll dc lc helled eupe he eld

Matr ontrcto n

hs sec descres he geerl reures f dec- d cd f rls used ke lgs

Manctrng Qat Inton and tand rarato n or S nt

hs sec ges geer chg ul ueesspecs cerc esg rcrd rees ls hs shpe dels d specl ls eured

arant and rant

Gve s dece els d rks r e erer he cuplg s plced serce u e ceed g egh-ee hs er spe

dor Data

hs sec decr es ll f he d reure he cupl ucurer s lsed e cupl dr cuplgd shee r prded s ep re cc d

Apd

he cuplg d shee s prvded e cleed hhe cuplg purchser d ufcurer cele erls, gur rurees (see NE re pers per gues re ge specl sec s l cplgsused fr rsl dpg s cldd sce s e re uuuplg desgs h he prculr eues hch r s cse h he prus specs fr hhspeed culg

INSION

he ms pr pr f e sll a cupg cul ks plc pr re f h ll prce


21/24

TUTORIAL ON COUPLNGS 6

dur ; hs s rculrl r h chgg fr gr dr culg sc hr r ud gl drcs h h culg drg src shsls d rs shul d rd r ll I s ls gd d h ccs d h u rs f h culg ufcurr jus cs s dd r shg ucdccus hr r ur us rdc s h c u urgculg sll hr u hr r

ur rs css s rls Hu shf s Ks

lg l scg

Hb to S t

T sls hgh r hu shf cc s hsrgh sh d r wh rrc Hr, hs sclly l usd l sd /gr ccs. I c dcul r h hu r s rc hr s hghlklhd f dg h s h s c r hub br Thrr s hgh spd shfs us prd ccs whhr kyd r kyls dsg s . S prculr ps em embe r :

h rs shuld ch rd g (

ur 5) h sh d hu cc shuld cckd wh chcs lu; rc u s ccl r k d ccs 85 rc mu r klss ccs f hcc ls h h r hu r shuld rchd rld usg scl lg gugs h hu suld r ld h sh sc ll rduc rdgs hch rrr dr r rrc d rss rrs h cul cu sh lur gur 59) rl ul chc d h hu d s h hu gug u r r uccss l j hr r r l s f ssr

g 8 Rt o p atc

n trn c-s sh dsg sdrds rsul rfr-c f 5 1 / dr fr kd hus d -rl 2 / r kls s hus dcg hu uch c rsrss h hu ll d ks culd rsrs sd r h hu culd s h shf ul chckh rrc d dr rur

Hb taato s kd hus r slld usg h d hu; l hs r s r ls rc ddsd f dc hch c sl dg h h

g onc o HbnS apn

usd rrl h lc f h hu h f mu chckd r d f h hu sll ch s chcs su r sd f h hu d shf chck hs; h u s hf cllrs r s c h hd hu sh r cls gr 0

F ggs

b

g 60. an t Me sre anc

Kyl h y d au l c sls a sr s in c h e a t cs d h hu c m o v e d h h g h dr xc Thy d o rqur m

e cr h kd sls wr d h up ucr sl in structions must be llowd. S om usr intal kyls hubsith heat to take advantage of the increase coeciet f ictionof a "dry connction, and us the hdrauics oy t m e thehub s. And others

mov e te 0ring grovs to incre th

co-tact ara, hich ork hen car is takn to ensur prcision

contact and bre cleanlis By th wa 0ings ar cesarif hd raulic instalation is used to seal the ol en tre i norrc

Kys

h s c ch/cug ch hd sh k sh cc d s ls h t s rls Ks us d sccl r u shf h us hgh s rgh ll sl d h u hd r rr z d lc f h r r

· h k shuld sug sd sd h s k d s ldg h hu k

· h k shuld h slg clc be- h k d h hu

· h k dgs shuld chfrd h rusds

· gl s shuld h ds h u hcl r dc lc h rl

· Double ks (at 180 dgrees) shoud ei xcl thes u fr lc

lur ll hs rd s c rs t ps dg gur 1 Lse s ll lw h k rlr shr durg k u cds "ll k u hfrd ds l rfr h hu kyv culd cc hu uls d hf r lancd withouk ds h k fd s mst U


22/24

12 PCEEDN OF THE E HTEENTH TUBO MCHNEY YPO U

Fg 6 ob wt Mt a ta k can cack b;b t o ap k no ca; c k t b cad;d t o oo k

he vd s cpleel, hu er erl crreclce

Agnnt

Flele cupls ccep sle dur per,u ecs se ll Cupl s eer resr fcs heshfs h sled d, ee huh he frces c ezed, he c ec che lerls d r Fr

hh perfrce er culs, sle prduceh er r p; dr cupls c ccep hr sles, u he c fl he he s l ceeds receds he es e fr eupe prs s skp le, d ps ddeds che pe rfrc es ver

Sce he pc f le culd ll er k, re he deled prcedures here uld e p he es

dvce fr he cupl p f e s ze heu f sle he cupl hs se he lges cupl lfe d fees prles

Aa Sacng

Ger cupls c e clssed s "lse pls dsce he ers c sld e ck d frh ll, re p rculrl sesve l spc f he hus sclls) Flele ere cupls he r hd recs f here l spc deecs e resd creses ere sresses Becuse , he lvees f he ches us e k d l sll f he dr cupl us e de cref, sce reures ccure l p s

Shf seprs d e seprs u es uredrecsel Cuplg ucurers prde sh u s rhe evle drece ewee he des s se prd he cul eld sepr, u he sh s crrec grss errr

Ms ele e re cupls re desd "r esreched sll, hch es he l ed edll sll Mche shs pcll rds h ecupl dur herl eps d h e c us sr hs vee e cupls re presre, s h heere w e "eurl ps he hesrech her per eperure hs plces upl he u sress d l rce lc r r

ISCENEOUS

Se eerl receds r cupl s ll re

s lls: P e serl uers d c r s e he

rh prs he crrec pss Isll he ls he prescred drec d us e ru e

reches he he he receded l Use l he cuplg ufcurers ls u s, d

ses , d replce he fseers rece erls

Hdle ele eres crefull, d scrh elees

Flele ere cupls see s d e llcllpsed sll he spcer, d vercls he eres , hch culd led prere flure

Red d fll ll srucs Cc h ucurerf here re uess r prles

INDGE

Cuusl lrced hh erfrce er upls usl lurce he rk er es h, u he l s hs secdr ee h hs e lrel uced s re dus h sk Bec use fhs, he eer l d prle h er cupls he fe· prles h cll eecused he l dr fr he urd fs u h, hch"pluged he dr le Fure 2 he er l s u rud he gurd h e sp cupl, pr he dzl hh urd eperures lhuh rduf ele e lee upl s fr urche s pr e


23/24

TUTORL ON OUPLN

he reedus ees, prculr drck hseerged fr elg he lu rcg l cresed dged hgher gurd ep erurs erefre, he usg eleelee cuplgs, cuplg gurds c e he sple l-gh eclsures used he ps, u us e cguredh erdcs d

© • H $'©$ © )©

H - H H

Figur Coupling Rotating in a Guard

lele elee cuplgs l prduce re r reuulece d hgher pressur e drels gurds h llger cuplgs spl ecuse ele elee cuplgs relrger deer he ec f hese cds s clled dag . here re prr cp e s f cuplg geerh ke up dge he cl der ec d he dsc ec

he clder ec s prduced rg ue sr gurd, here he r er he sp g ue hs uelc d e r er he spg ue hs u elc d he r er he sr gurd hs u elche sher eee he lers f r dre elces cree

c hch geeres

hehe dsc eec s prduced prs s lr rg pleshch cree r fr he sler g I he serg 0 hs r crcul fr s ller dee rs lrgerdeers rd he gurd resul s dc d sc pressure drels hrughu he e csure d ru he cu-plg gure 3) he dsc eec s r ll he lrger dgeprducer d he cuse f s prles hrd crur she urulece prduced cured r epsed sces

8-

� D ! �� 8 8 8

Figue 63 Ai Flow i Eclosure

0

;D®

f

hch c e redl crreced desg d s r rur he erll prle

here re sc res f prles h dge c fe erlp he prles d pressure prlem H sgeered cuplg eclsures r frc d m e ssped Oe d hs s clse , r "sel gurdd le he he e crred rd r ce eer, gurds he ee k ge h eugh l r p ,

s hs culd e hzrdus prcedure he lere s ll he url r crcul rud he cupl crr he Sce r s pr cducr, s p reu reshgh d prper rug fr hrugh he eclsr rduc e gd resuls Spe cc gurd desg feures re e pper prese ed he Proceeings of the 14th Turbom ch rySposiu d ll e repeed here, ecep r fr fe le/ule pr reuree s s flls

here shuld e eher le prs d e le pr,r e le d ules, prduce l r rs s eclsure If sgle, le prs re used, he r ll e lp rud he cuplg e sp d e ehuse m egurd h eglgle clg

he le pr shuld e gel he cupl r(h r drec) d shuld ed l preure l

"pull r he ec lsure he ule pr shul d e gel he cupl r

(gs rl drec) d shuld e hgh p ssu r lc "ush r u f he eclsure N h s r mll gd de pu ules he lrges cuplg mr ,sce he eree pressure d urulece h p ll rduce uc h r

Ol sels shuld e kep sepre fr he ddred s clse h e sel s pssle If l s ll erh, ll s r d culd e preeed m d r g pressue d hch ll prduce l "ug esherg f he erpped l ll geered ereel gh e csure eperures

Pressure prle s d rll cree hgh gur e m rures u he c prduce perg hedches e ms

c pressu re prle les lrh sels re le elee cuplg c "suck he l u f he sl (gur4) hs hppes ecuse he dr cuplg s lrger m e rd he dsc ec geeres re r d hghe ress urederels he r he sel (d sh s le ressured, herefre, he pressure derel crss he l s cresed sple slu s lle hch les s llg "e ple fr f he sel gure 5 hs pl s l ed he che d ses up d lere r p hh ,lg h he specc ple clerces, creses h ressure he sel, here redc he derel pressu e rs s sel

/ =

Figure 64 A ir Prssue an crculation


24/24

64 OED OF HE EEENH UBOMCHE YPO U

Figue 6 at

O u f ld h hgh puu h d l lg ulg d.

d huld d du ul a d l v huld dd wy h hy ld hghly uz Wdglul ulg d gud u ll lg u h ll d mpl d d u l ud dg h u z uul d d l lgl h gu dg k lul u lvl l u ll l h g kh hul u wh u z d flw ll ulm

BIBLIOGRAPHY

l W, M l f Dl Culg Sf Nvl d gg ( 1966).

B . N PI 671 Culg h I h? odg o t t boa ou mh L mt hl -g T & v Cllg T(1981)

Cl . d u . "D ul g -lu odg o t 4t bo Soum u L m f

�hl gg T & Uv CllgS T (1985

Cl . "Fll Cplg Illt lC P T 191

Cl . "Hdulll Fd Hu T d P- od o t Nt boa ou um L pm f hl -gg T & U Cllg T(198)

G C "h f h Cul m-h Pl Dlm Sm uh S SM l 198)

Mu J R "D v Dhg Culg h - (Jul 24 1986)

u J R g G Culg phgmCulg Hd Pg (O 88)

Mu J R "Cl J D g l dl l Dkk d (1986.

P wl B Jh C M "h dl f Fll Mll Mm lg I-l C Fll Culg Hh P- d Sd (J 977

Rhd S J " M V l K v u-l Sh P (Ju 1988)

S M HghPm mh Clg N D f ( 198)

the application of flexible couplings for turbomachinery

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