Problems in Boiler Feed Pump.pdf

PROBLEMS ENCOUNTERED IN BOILER FEED PUMP OPERATION by r, Elemer Maka e e ee    ve ev Pump problem a well a pumpcaued feed water tem  problem ca ca  be cateoried i te llowi llo wi wa  Pump tpe ile or multitae dier or volute oriotal or vertical etc) o Vedor o Maucturi QA (Qualit Aurace)   ecolo (Hdraulic Lubricatio otorDyamic etc)  Deig cocept  Feed water tem or vari o Applicatio urbie or motordrive

Elcmr Aakau ivn hs P. D 0 P Uiitu he attede Tehia sty Bapest w c cicd Maste's Degee chaial Egeeig Dr Makay has 1okcd B  stigs esg ad dDeLaa/ i celopt a of Sie boile ed he has as a ad toS 1975 he has elet we \rkeepe  la jJ! j(!cs j ·· COJics  lea Pay s ooled ca ad atho I cal cal pape o ad otor

e 

Operatio (cycli or bae load plat) Maiteace ad Service etc However at ti poit te mot objective i to ide tif baic caue of failure or operati clled GENERIC prolem tat are directl applicable i eeral to all pump product e autor a bee ad i coducti a urve ad ilure evaluatio evaluatio for te U S Utilitie o utilit pump  wit pecial empai o boiler feed ad reactor feed pump e urve ti r r a allowed u to ideti ideti  everal tpical tpica l problem proble m area area Some of tee are e Pump draulic itabilit (ee Fiure  Beari tecolo ad rotordamic e Seal (epeciall for Nucear Primr Coolat Pup) o Axial balaci devie balace drum ad dik) e Artiiall pued pump eciecie e Lack of Stdard r preure pulatio amplitude ad  frequecie allowable vibratio level at variou fre quecie pump a axil vibratio level ad freue cie

ABSRACT

Altou mecaical ad draulic i cetr al pump caued a coderable amout of r lare Nuclear ad Foil Geerati Statio Power Plat Availabilit" a relativel limited amout of rearc work a oe i ti area e autor make a attempt to outlie  problem i eeral ive defiitio for ydraulic ydraulic ad damic Itabilitie outlie te Mecaim tat create tem etablie a operati peed ad ow rae r lare  pump ad dicue ow to treat te above ubject ubject we eld  ilure ocurred Iteractio betwee draulicall iduced  fore ad a d beari dei parameter ad teir iuece o rotor vibratio caracteritic i empaied Frictio iduced dicued ee ce re  partial frequec mode are iable ad ca iuece rotor ad beari dei require met ca cae rotor tabilit ad te appearace of te  pump rotor critical peed peed  Compario i made betwee verti call ad oriotall orieted pump ad betwee volute ad diffuer tpe e autor alo outlie te miimum i trumetatio ecear to idetif problem area before ad aer failure occur ad upport ti wit actual eld failure cae It i outlied ow a imple factor (wite) tet ca ucover potetial future eld problem Area were tem atic  futre reearc ad developmet work i ecear are  poited out

 

   . 

INTRODCION

A ie of Nuclear ad Foil Power Geerati Statio row te uexpected ad uexplaied mber of lare pump  failure or pumpcaued tem operati dicultie ao row A oe bei to pa cloer attetio to tee proble it becoe clear ta a lare percetae o tee faiure ca be traced to rotor itabiit (t eat i apperace) ocurri epecay i te lo percet ow (or pa oa) reie i  particr i te ecircuatio (ii o) oe

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Figu Figure 1. Head-Capacity ead-Capacity Cu Curve of Unstable Unstable Boiler Feed Feed Pump Parallel operation operation is fc fcult lower lower fows.  Head  Head is unsta unstable ble below below approxima approximately tely 65 percent percent fow fow resultin resulting vaouss pump or  g vaou pump or  F. W. W. s ystem ystem olm cus y  impll sig.

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 4

PROBEMS ENCOUNTERED IN BOILER FEED PUMP OPERTION BLE SSIN FEQUENY S ELY DOMINT MY EXCITE LOE FEQUEN SONSES

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  Fo n and Around a Pu Imeer Fgure  at Degn Fo Oeaton Foton  LL (1) and RECRCTO ow 2  & 5  a hown aay n Fgu 7 

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ALAYS PESENT FO BOTH DIFF. D VOLUTE TYE S BE DOMINNT FOR VETICL DESIGNS BELO POX % DESIGN FLOW

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nhronou and unhronou Frequen  Haua Indud Dnam Fore NAC AN HRALC NSABLES

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Deiti of DYNAMIC istabilit is give i Rereces 4 5, 12 ad 13 ad i ma ter publicatios Subjects suc as bearigs seals wearrigs rubbigiduced wirl f a saft oil  wip etc  are relevat ere Most f tem are relativel well deed areas; terefore discussio of tese subjects is eglected ere (wit te exceptio of bearig stabilit)  e deitio of HYDRAULIC istabilit especiall at lw percet pump ows is give i Referece 12 outliig te mecaisms creatig tem Hdrauic istabilit is also classied b pump stage geometr wic is more preferred b  pump desig egieers Figures 6 ad 7 sow i a simplied  wa ow mecaisms at various geometries f a pump stage ECHANSS OF HRALC NSABL

 e follwig ow mecasms pla a imprtat rle i creatig pump rotr istabilit o wat degree te are iuetial is ot et completel kow toda For crrespodig geometr see Figures 6 ad 7

• •  • • • •

Secodar ows (Figure 6) Stall (Figure 7) Leakage ow suc as troug wearrigs • Hdrodamic (matrix f four coeciets) • Hdrostac (matrix of four coecets) Ustead ow uctuatios ake (blade passg equecies)  urbulece Cavitatio

IN  IELLER EYE DUE TO W INCIDENCE   ORMTI O TLL (ISULIZED ON EERINT TEST RI) Fgure 7 Formaton of ta (a on a Curvd a and (b n

an Imeer ye (Roang a

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Equvalet drodaic mass Hdraulic ubalace  e last two tems are ot reall ow mecasms but are importat peomea to be lsted Bot ma cause ma udetectable eadaces for cetrfugal pum especall for uclear prmar coolat pumps

 4

PROCEEDINGS OF THE FIFTH TURBOMACHINERY SYMPOSIUM

PM SAGE GEOER

Mot pump deier like to ave a claicatio of pump  problem  pum eometr rater ta b ow mecaim or oter claicatio Aai wt te aid of Fiure 6 ad 7  we ca cateorie our objecive b pump tae eometr uc a • Impeller e (ilt) itabilt • Ipeller dicare ilit • Iteral itabilit (impler ad/r dier) • Exteral itabilit (ap beind impeler ub ad roud uuua important for igle tae doube uctio reactor  feed pump) • earri iteractio • Cai iteractio • Hdrodamic wirl (we rotor motio et i pical motio of te rotor ive re to additioal draulic actio) Hdraulic itabilit ca be detected b examii te  pump Headapacit curve (ee Fiure 1) If te curve i at toward lower ow or epeciall if it i droop" mot likel  pump or tem vibratio wll be a problem Ma time te  problem coe om e fat tat arctectegieer are pui for ier ta poble eiec tat ca be acieed ol b deii te pup draulic compoet for te uaatee  poit aloe i te reult i utable operatio at lower ow I mot cae ol a ew carell died pump impeller ca olve te problm we draulic itabilit  preet If a pump i purcaed but ot yet deivered iit o a ood op tet wi owwie equall ace tet poit If a poit i ier i te idcapacitie ta eibori poit o ot accept it iit n reteti If t i a ew propal prper  writte ad executed pecicatio ca take care of ti peomeo o pecicatio do t pre ti ubject ard eou Hdrauic itabilit i te umber oe Outae produci pomeo due to te fac tat te vibratio repoe receive edle eer exciti iput from tall blade  paig ad oter ource PUP E FFCENC

Articall iated i ciecie are "cs b ma rt ee Refrece 1 1  62 rt pararap) ive a  lear explaatio of ti peo Atull eciec doe o e o e red to oba od pump reliabilit ow ever a demad for ueaal i eciec ill reult i owered mcie reliai FER VERS

bui) type eal Alo for te more complex eal type cotiuu killed attetio i eeded at te ite ic ofte i ot availale Labrt el are te leat deadig ork ore of utility pup I n order to avoid ture dipute iit o avi labyrit eal e ol reao for oter eal tpe (mecaical cotrolled leakae etc ) i to bri drulic lo (leae) dow o te apparet eiciecy of te macie look ood ad uarateed commitmet ca be acieved BALNCING DEICES

Axial balace dk device are equet caue of failure From tecology poit of view te belog to te ae categor eal Setime lack of pace available i a de  prevet pplcatio of proper dimeio wic make te device receptive to pump itera pump draulic itabilit at lower ow damic unbalace of copoet beari itability cti iduced a wirl etc) or exteral excitatio reultg i ueceary failure You ma ear from te  vedor tat te dik i te at valve o te pump amely it \V il bere ay oter compoet i te pump  i ot o A properly deiged dik ca lat forever ad ca ave te  pup om detructin BEARNGS, ROOR DNAICS, OL WHP, FRCION INCE WHIRL

If a prble i traced to a beari deig or eari tpe caed deciec electio of proper bear parameter (L D rti radial earce bearig load pri ad dampi coef ciet etc ) il i ma cae reult i a ucce olutio I a ew acine it n performg te proper rotordamic aai critcl peed a decto rotor repoe ear tabi)  t peed ra of appcatio ad to veri te reult durig acceptace tet A ood coa dow tet for examle ca ver te locaton f crtcal peed If te  pump maximum perati peed i above 15 tme te rt lateral crtcal peed nt  r te pup wt tale tpe joural beari e lat pae of Referece 4 outlne t Fiure 8 (alo Referece 4) ow i a overimpied mer te ect of te beari prcipal prig coecient o rtor critical peed I eera it i recommeded for exible a to ppl dyamicaly table beari uc a tilt pad tpe wic are eretl table i teor A rotor i lled rid  it erate low te rt critical peed above tat it i called exible e autor d occaioall te bear



 i queti come up eut i power ttio  i oe d you rme?  reay eed o te idi  vidal deer' bilt w rage ecienc ad tabilit Formatio o tabilit i t ier pae trg deped on e eeerati rae f te uid ow  diuer deerae te ow terf it i e recepie to para to ad tall formain ece to pat lad iailit O te otr a  te d  a volt te ow uuall i duped ito te icare oe wc e cae otr prbl  i due to t ct tt te acuated ec o te ble olte tue d dier blade pai euecie aect t  co o em epecily r a ii ae ractor tem wre e rt tr ee cotrl i  e it L

Ale tecolo r a dei i mial r i pd piatio or a otr a l bd

DC  nc   

iu 8. ffcs of  icpl Spg Cocs  Roo i Sp   l F ump Tu D  ous ig Tps u  f pump  co c  a fexibe copling,  the ccl sp rpe  ui y

9

POBLEMS ENCOUNTEED IN BOILE FEED PUMP OPEATION ng nstblty ses wth hgh speed pumps wth tltngpd berngs Fgure 9 shows one suh se where the multstge boler feed pump suddenly beomes unstble t twe the rst rtl speed The equeny of nstblty ws lssl bere hngng to tltngpd berng. The new berng elmnted the lssl hlfequeny whrl, but not t the low frequeny s shown n Fgure 9 The nstblty sets n only t ertn  pump ow ondtons nd only bove twe the rst rtl speed Fgure 10 from Referene 6) shows the behvor of  snglestge double suton nuer retor e pump The orgnl pplton of these pump types ws low speed booster 1800 RPM) Eonoml resons dtted  speedp to  3600 PM for the booster, nd to bove 5000 RPM for the nuler feed pump ppltons Hgh speed booster pumps ehbted more thn usul eld problems but mnly t low ows, espelly when mnmum ow rerulton) ws set to less thn 25% pump desgn ow Most ses were looked upon s system desgn problems, espelly ppng geometry Sgnfnt mount of money ws spent on ppng hnges ·th very lttle suess. Wth onstnt speed retor ed pumps Fgure 10 shows one t 5400 RPM) we found serous problems s shown n Fgure 10, ses " to d" In se d" the pump beme unstble n the low ow re t 3600 RPM. At 4000 RPM the only remnng stble pont ws the desgn pont, nd the pump ws unble to operte bove 4000 RPM n ny ow rnge Redesgned berngs llowed the pump to operte n the rnge shown by lne " Prtl orretons to the hydrul omponents resulted n lne b" whle " ould be heved only by omplete redesgn of the pump nternls. Present U.S.

 prte s to pply  vre spee re I te rve s n eletr motor the SynhroP" whh hs hydrl ouplng wth  bultn stepup ger) s  most eonoml rrngement. Constnt speed retor feed pumps n be found n the U.S only n smller nd older nler unts nd wth unfvorble eperene. Fgure 11 shows sh vbrton mpltudes t vrous frequenes for se d" of Fgure 10 when the pump ws opertng t the nstblty lmt lne. Drvng the pump nto the nstble regme by ny smll mount resulted n rpd nrese of the hlfequeny omponent In two nstnes the mntenne rew lerned tht, f suh vbrton sets n, t wll ompletely destroy the pump rotor Applton of tltngpd berngs dd not ompletely solve the problem, howeer sudden destruton of the rotor dd not our gn.

  w       i 10 Pum Hadlo haati a  54 RP M

  RiOfl?UM: S!NGLTACE tJ DIKZ.·

. NPTNG P£ · " 5, M

i   PM  PT PMT T Fgue 9 Vbaton Fequency - v - Spee Caue an cue o common vbaton pobem o centuga pump team &  ga turbine fan & blower compreor and other ceniugal equipmet.



O VUl N -   N   S Fgue 11 yucay Inuce Intabity Become Song Enough to Detabize the Outboa Beang ch Then De veop aFequency Wh ( /2) I beang i tabe t can till develop an apparen haunc hirl hn rotor rb bing occr but the uecy i nction of% pump o.



PROCEEDINGS OF THE FIFTH TURBOMCHINERY SYMPOSIUM

Fgure 9 the Sunburst" chrt) s n eperence chrt nd cn be used to dgnose cses where the vbrton frequences cn be determned If vbrton mpltudes pper wth  equences lower thn the opertng speed, the nstructon  Fgure 9 s: Use tltngpd berngs" In generl, they brng help n such cses, but one should relze tht berngs c cope \th hydrulc forces only up to some degree; beyond tht, the soluton les n the desgn of the pump hydrulc compenents Hydrul forces, such s wke ect t blde  pssng frequency, or rdl forces nduced by mpeller to dser/volute ntercton, cn be strong enough to ecte the rotor to lrge mpltudes If ths s coupled wth dynmc unblnce of the rotor, rubbng t close clernce surces my occur tht cn nduce  counterrottonl whrl wth  frequency less thn rottonl Ths s  selfectng type vbrton, d f unbounded, wll grdully or sometmes volentl grow d destruct the rotor  double frequecy component my lso pper, gvng the ndcton of mslgnment, s shown n Fgure 11 Counterrottonl equecy vbrtos re unpredctble The lowest equency the uthor mesured  ws 008  rottonl speed, nd the hghest 0 5  rottonl speed For rble speed mchnes ths frequency s  ncton of ow nd speed, whle for  constnt speed boler feed  pump t s  ncton of pump ow lone The whrl equency rton usully ncreses wth ncresng pump ow, s show  Fgure 9 RAIAL RALIC FORCES

Refereces 10 d 13 dscuss the subject n gret detls One must dstgush betwee sttc nd dynmc rces both ncresng  mgtude towrd lower ws, hvng  mmum t mnmum recrculton) ow Unrtuntely ngles of the sttc forces, nd the frequeces of the dynmc rces cot be clculted they hve to be mesured for ech ndvdul cse More mportnt, ech desgn hs ts own ptte Results cnot just be etrpolted om one desg to nother Ths s one re where ture work s essentl SANARS

Wht re vbrton nd pressure pulston lmts wht s good, wht s cceptble, etc re frequent questons wth hgh energy nput pumps  power sttons For ll cses  serch for mpltudes contnuously goes on, but t s most m portnt to nd the ssocted FREQUENCIES We re usully lookng for:  Dynmc blncng mnmums  brton of the  Rotor n the  Radl drecton  Axal ecto  Structure  Ppng  Pressure pulston n the  Ppng  Pump nternls  Sfe opertng rnges, such s  Speeds Mmum nd sometmes lso mnmum)  Flows, epeclly mnmum recrculton)  Pressures, tempertures, etc NAIC BALANCING

The US Nvy specctons for llowble dynmc unblnce qunttes re cler, precse nd dequte for ny  pump pplctons

  6  

2 6   - ( 40.

2



Fgur 12 Aoab Roor Vbaon Lv for Cnga Mahnr Maud Rav o h Barng Ca (Ex mna andar) IBRAION

Rotor synchronous vbrton mpltude levels re shown n Fgure 12 s mesured on the sh reltve to the berng housng The mpltudes rer to only snchronous speed frequeces once per rotor revoluton) Fgure 9 shows equences nd some smpled eplntons or ther cuses nd cures l vbrton level s n ecellent ndcton of pump desgn qulty for sngle stge double sucton pumps, such s booster, nd nucler ed pumps It cn be used to detect hydrulc nstblty, nd cn be used to nd sfe mnum  ows Recrculton ows) There re no estblshed stndrds mong mnufcturers or users Fgure 13 s n emple, whle Fgure 14 shows  method how  vbrton dt ws used to set mnmum ow qunttes n severl nucler unts How to mesure mpltudes nd equences s even more mportnt Fgures 15 nd 16 om Reference 4 show how msledng ncorrectly mesured dt cn be, whle Fgure 1 shows how  correctly nstrumented mchne ws sved om destructon PRESSRE PLSAION

There re o pressure pulston stndrds vlble t present Oten  3% mmum o the pump produced hed mesured on te dschge sde) s quoted, whch s stscto n some cses Recenly nlyzed cses reveled tht vendors lmost lws uote mptdes t the Vne pssng" frequency number ofmpeller nes Z" tes rotonl speed N," e Z X N) re 3 sows scat ampltudes at Z X N bt the sae ata rece  aetc tape a plae ac at a lower speed shows tht the mpltude t vnepssng frequency s ndeed sgncnt Fure 20 shows dt  collected on nucler feed pumps n nstlltons wth pump nd system d

5

PROBEMS ENCOUNTERE IN BOIER FEE PUMP OPERATION

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U AYZER ?: X 1

Fgure 5 Orbit hape at the Turbine Inboard Bearn g Bler ed pump and turbne rve coupled ae  ): Bre hot algnment ith large bearng clearance Cae (2): After hot algnment beang clearance reuced b 4 m on the iameter Both at the turbine rotor rt ctical peed Notice that one vecal probe ould not h an change in bearng behavior One probe 20° of vertcal pitn would ho the oppoe ct  probe perpendicuar to each other cillocope an equenc anazer give clear pcture.

Fgure 13 PeakToPeak Preure Pulaton ( M Meaured n the Dchae Nozzle and Rotor Aal Vbraton ( !)  a Hgh See ec ee Pm Wi wo D e mel is cge Cgris Pm Effciecy  00 Pce w Ws e Sme i  Cses  90 %

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OSCOSCOPE OUTPUT WTH O PBES

Fgure 16 oiler Feed Pump Uncoupled Fr the Turbne Drve Orbt hape at the turbne inboard beang at he rt crtca peed. The vbraton reading n the contrl room howed 14 ml wle the tre ampltude  46 m Meaurng vbraton level of a hgh peed rotatng machne in a ngle drecto can not onl mleadng but al danger o.

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 t              f t     J  I {c) A REClC   % IER  RIGIHA igure 4. Shaf xil Vibraion of  High Seed, ingle Sge, Double Suctin Nclear eed Pum at Minimum low Operain. Direcly alcable o any ngle age double suction cenrifga pum, uch a connae, boer, or any chemicl roe um.

 cultes  recommended Sfe lmt lne" s lso shown me sured n the pump schrge Ths lmt lne s contnuously subject to revson s more dt s collected In Fgure 5 we mke n ttempt to epln equences nd mntudes of hydrulclly nduced dynmc forces wthn the pump Fgure 2 shows  equency plot wth the d of n RT Rel Tme nlyer) of  nucler rector feed ump The me

Fg ure 17 Shaft Orbt Meaured at the Turbne Inboard Beang at Vaou See on jne 5 175 Dratc ncreae of mplitude conclued the tetng Vbration became volent at the r crtcal peed dng coaton

surements were tken t the pump dschrge The mpltude t the equency of N/4 N=rottonl speed) s very strong lso  hgh mpltude ws epeenced t bout one CS  whch cn nuence the feed wter ppng control vlve con trol system rector wter level nd the rector control system s sho n Fgure  The pulston wth the lo frequency cn be  domntng respone Its uence on the control system nd the stem turbne tself cn be so strong tht t my force the turbne nto  hh ld oscllton wth hev  vbrton of the whole stem cycle In one rtculr cse when cntrol ws ut on Mnul erton bece nrl rvng tht t ws cuse by the contrl syste whch be

5

POCEEDINGS O THE ITH TUBOMCHINEY SYMPOSIM Ns in European unt

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came eced by the pressre plsato geerated by the reactor feed pmp proe by measred data see Fgr e 2 to 5 ad 18) Fgre 3 s a typcal example Pressre plsato mea sremets  the reactor feed pmp dscharge ppe dcate oly" low eqecy N/4) plsatos of hgh ampltdes, g g a clea bll of health to the pmps, pttg the blame o the ppg system Fgre 4, howeer, shows that the rcg cto, resposble for the lower eqecy ampltdes  deed, s the blade passg freqecy To aswer addtoal qestos, sch as what are the e qeces d the ampltdes sde the dret parts of the  feed pmps, ad, becase  oe partclar case the above metoed eqecy story reslted  too mch otage of sev eral large clear statos, sch measremets are ow tae All of them show moderate ampltdes at blade passg e qecy, howeer, aalyses, smlar to that show  Fgre 4, showed that balde passg freqecy was the real case of the system problem edesg of the pmp mpeller wth deret mber of blades, bt more mportat, wth ery careflly selected mpeller desg parameters, fally elmated the ds  pted problem It was obsered may tmes by the athor that the ampltdes at blade passg eqeces Z X N) ar e steady  matdes forcg fco), whle at lower eqeces they  form, dsappear ad reform aga excted system resposes) Fgre  s a smled smmary of freqetly obsered y dralcally dced freqecy responses measred o the  pp ad o the feed water ppg Sbsychroos forces ca be detrmetal, resltg  smlar erace to Ol , oe msleadg the estgtor Oe sold dst sh etwee olwhp, rbbgdced whrl, ad hy drlclly dced whrl Ofte these three ppear alke, ad ca e toard flse coclsos he reqency ool s depedet of pmp ow, whle hyrlc stablty s a cto of both, speed ad ow How c we ow represet the above metoed statc ad dyamc forces whe performng rotordyacs clcl tos The sttc forces ca be represeted smlarly to be

100 0

HYDRAULCALY NSTABE EGIM

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% of aed

10(

igur 19 Antiipatd Usful Oprating Rangs for Pups  n Lar r n Foss nt

gs, seals, d wearrgs, ael wth sprg ad dampg coecets Sychroos rces ca be represeted as dynamc balace Other tha sychroos 1  Re) ad sttc forces ca be represeted oly whe sg osychroos, or o ler compter programs SAFE OPENG RNGES

Here we cocetrate �the sbject of pp Mmm"  ow, ofte rerred to as Recrclato," or smply Recrc"  ow Fgre 19 shows  ow lmts for vros pp types ad applcatos Becase of kee competto  the  pmp market, edor prces, pp ecences, etc all ll  wth a arrow rage Coseqetly, the oly attractve  BUT ARTIFICAL des hhlght a marketg ma ca explot s mmm ow For example, stead of arateeg 25% recrlato ow, a vedor mht promse oly 5 to 10% The the ecrclato le d ts cotro valve c be redced  sze o, say 8 ches to 4 ches, ad he ca oer a savg  the oerll prce of the feed wter system ppg Ths seems attracte tally, especally to the rchtect eeer, bt ot  whe yo cosder the extsve pmp dmge tht reslted  om lo recclato w The desg marg bad  Fgre 19 represets a regme  whch the experece ad assmp tons of the pmp desger ome to play Safe mm ow  for a large rector feed pp s NOT LESS" thn 25% of desg ow, bt may be as gh as 45% whch s ot acceptable d the p peller desgn s to be exed nd mproed see Fgre 13 as a exaple Other qttes sch s mxmm ow veloctes, os ad speeds are well dscssed  Referece 1 hece ot ds cssed here Other staards and easrg des are ot led  Referece 4 There are my other mortat sta drds for cetrgal pmps, one of them s the radal gap between peller O and ser/volte tonge nsde dmeter Te closer the ap s te her the  ececy

5

PROBLEMS ENCOUNTERED IN BILER FEED PUMP OPETION

Figre 20 Char Efficiency vs Specific Spee N, as a Fncion  Capaciy QGPM

s however, beyond  cert lmt the pressure pulsto, cused by blde pssng pheomeo, becomes srog eoug to destroy pump compoets, but more mportt, the whole  pump tself. For dser pump the gp must ot be ess th  3% of the mpeller O.D., for volute type pump the stdrd s ot to be less th 5%. WHA CAN FACORY ES ELL ABOU FURE PROBLES

Fgure 20 s  gudele for wht the epected pump ececy levels my be. Fgre  shows  emple of  troublesome pump hed curve shpe. If the hed curve s droopy or t towrd decresg ows, or f t hs  KINK"  t, the pump should ot be ccepted, becuse, pump, ppg, cotrol vlve cotrol system ml   ctog my low  the ture. Aze ALL pressre pulsto rges, do ot cept results just t the blde pssg equecy. Alwys sk for pro  per strumetto t the bergs see Fgures 5 d 6) d  for results t  wde equecy rge, ot oly t opertg speed see Fgure ). If pump hs  blcedsk devce   wys sk for the dsk leko  ow  the complete opertg rge of the pump, s show  Fgure 2. REFERENCES

. Mky, E. d Ewers, B., Hydrulc Problems  Nu ler Feed Pumps Demd Attento to Cut Costly Downtme,"  Power Mrch 975. 2. Mky, E., Choose Feedpumps Crell for Cetrl Stto Servce,"  Power Generation Planbook 974.  3. Mky, E. d Sez, Jose Hghpressure Boler Fee Pump Troubles Cler Up Aer BlcgDsk Chges  Power Jue 974. 4. Mk, E. d Doersberger, J., Alyzg d Cor retg Vbrto Problems  Rottg Equpmt: A Cse Hstor,"  Power Otober 975.  5. Mky, E., Adms, M. L. nd Shpro, W., Desg d Procremet Gude for Prmry Coolnt Pumps Used 

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5    50  L L70

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Figure 21 How oiler Feed Pu Failure a Intereted and Degradation  the Pu  Followed ith ile Intrumentation at an 800 M Unit If um imeller head harateti wa table mot likel none of the ilure would have ourred

LghtWter Cooled Nucer Rectors Hdbook  prted by O k Rdge Ntol Lbortory, November 972.  6. Mky, E. d Drechsler, G. E., Trobleshootg Lrge Pumps for Nucler nd Fossl Sttons," Power December 973. 7. Mk, E., Improve Power Plt Avlblty: Lrge Pump Problems," ERI Prect Report 64, October 20, 975 8 Mky, E., Idetcto of  Boler Feed Pump Problem   Lrge New Power Geertg Stto," EPRI Project Reprot 64, Mrch 976. 9. Krssk, Igor J. d Vletn, J. E. C. Stem Power Plt Clcs: Boler Feed Pump Drves for Lrge Stem Electrc Sttos," obution Februr to November 966. 0. Flocc, D., Hydrulc Problems  the Development of Rector Pumps," KSB Spel Prtng, No. 2, September 974. . Mky, E., Elmtg Pump Stblty Problems,  Power July 970 2. Mky, E., Dscusson o Clculto of Fored hrlg d Stblty of Cetrgl Pump Rotor Systems," by H. F. Blk, Trstos of the ASME, Augst 974. 3. Mky, E., U.S. Prtce o Boler Feed, Ncler Feed, nd Other Utlty Pump Applctons Cuses nd Cures of Feld Flures, Synhrotorque Symposum, Munch, Mrch 25, 976.

54

PROCEEDINGS OF THE FIFTH TURBOMACHINERY SYMPOSIUM