The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote...
Transcript of The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote...
![Page 1: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/1.jpg)
©2016ConcoServicesCorp.
TheScienceBehindEddyCurrentandRemoteFieldTes8ng:
forCondensersandHeatExchangers
ConcoServicesCorpora4on
![Page 2: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/2.jpg)
2
Introduc4on
• WhatIsEddyCurrentTes4ng(ECT)andRemoteFieldTes4ng(RFT)?
• WhathasDriventheAdvancementofECTandRFTTechnology?
• ProbeConstruc4on• FillFactor• Applica4ons• Calibra4on• Singlevs.Mul4-Frequency• Conclusions
![Page 3: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/3.jpg)
3
WhatisECTandRFT?
• Non-destruc4veinspec4ontechniques.
• Basedoninducingelectricalcurrentsinmaterialsbeinginspectedandobservingtheinterac4onbetweenthosecurrentsandthematerials.
• Usedtomonitorcondenserandheatexchangertubeintegrity.
![Page 4: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/4.jpg)
4
WhatisECTandRFT?
• ECTandRFTtechnologycantraceitsrootsbacktoMichaelFaraday.
• Modernelectromagne4ctechniquesrelyontheexperimentsperformedbyFaradayinthemid1800s.
![Page 5: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/5.jpg)
5
WhatisECTandRFT?
• Eddycurrentsaregeneratedbyelectromagne4ccoilsinatestprobe.
• Astheprobemovesthroughthetube,defectsinthetubewallwillinterruptoraltertheamplitudeandpaYernoftheeddycurrent,changingitsmagne4cfieldandcausingavarianceinthecoilselectricalimpedance.
![Page 6: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/6.jpg)
6
WhatisECTandRFT?
• Bymeasuringtheprobeelectricalimpedance,atrainedtechniciancan“see”defectsinthetubewall,suchaspi]ng,cracking,erosion,corrosion,grooving,dentsandchangesinwallthickness.
![Page 7: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/7.jpg)
7
WhathasDrivenTheAdvancementofECTandRFTTechnology?
• Worldwideincreaseinthedemandforpower.• Increasedfocusonpowerplantequipmentreliabilityandefficiency.
• Needtofindsmallerandsmallerdefectsthatcanleadtotubefailure,causingadropinMWoutputortriggeringaforcedoutage.
![Page 8: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/8.jpg)
8
ProbeConstruc4on
• ECTandRFTProbesconsistofacoilorcoilswrappedaroundastructure.
• Designwilldeterminehowtheeddycurrentsareinducedandhowflawsaredetected.
• Builtonanonconduc4vebody(aircore)orusingferritecoresandconduc4veshieldingtohelpshapetheeddycurrentfieldforspecialapplica4ons.
![Page 9: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/9.jpg)
9
Probe(Pancake)Coils
• Designedtotestthesurfaceofmaterials.
• Canbeappliedeffec4velytoplatesandwelds.
• WhenfixedtoaspinningdeviceitiscalledaMotorizedRota4ngPancakeCoil(MRPC)andisveryeffec4veontubes,butis4meconsumingandexpensivetooperate.
![Page 10: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/10.jpg)
10
BobbinCoils
• Allowfortheinspec4onofinstalledtubesfromtheID.
• Interrogatestheen4recircumferenceofatube.
• Themostwidelyusedcoil.• Consideredthe“workhorse”ofthetubetes4ngindustry.
![Page 11: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/11.jpg)
11
Encircling(Feedthrough)Coils
• Allowfortheinspec4onofroundobjectssuchastubes,wiresandrodsfromtheOD.
• Interrogatetheen4recircumferenceofthematerial.
• Usedmostlyinproduc4onmonitoringac4vi4es.
![Page 12: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/12.jpg)
12
AbsoluteArrangement
• Coilworksindependently,makingnoreferencetoanyothercoil,andisaffectedbyallchangesinthematerial.
• Usuallylimitedtousebyconduc4vitytesters,coa4ngthicknessgaugesandsmallsurfaceridingpancakecoilsforsurfacescanning.
![Page 13: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/13.jpg)
13
Differen4alArrangement
• Twoormorecoilselectricallyconnectedtoopposeeachotherandlookforanimbalanceor“difference”betweenthetwocoilimpedanceswhenaflawisencountered.
• Subcategorizedintotwotypes:• SelfComparison.• ExternalReference.
![Page 14: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/14.jpg)
14
SelfComparisonDifferen4al
• Twoormorecoilselectricallyconnected,placedincloseproximitytoeachotherandwoundinopposi4on.
• Verysensi4vetosmallvolumeflaws.• Minimizenoiseduetoprobemo4on(wobble),temperaturevaria4onsanddeposits.
• Effec4veindetec4ngabruptchangesinwallthickness.• Cannotdetectgradualwalllossassociatedwithsteamerosionortube-to-tubewear.
![Page 15: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/15.jpg)
15
ExternalReferenceDifferen4al
• Twoormorecoilselectricallyconnected.• Coilscanbeonthesametestpartseparatedbyadistance
toavoiddirectcouplingbetweenthetwocoils.• Onecoilcanbeonthetestpartwhiletheothercoilsitsin
afixedloca4ononareferencesamplethatrepresentsnominalmaterialcondi4ons.
• Sensi4vetoallmeasurablechangessimilartoabsolutecoils.• Datacanbeerra4c–muchlikeabsolutecoils.• Typicallyreservedfordefectconfirma4onagainsttheself
comparisondifferen4alchannelsandfordetec4onofspecificdamagelikeerosionandtube-to-tubewear.
![Page 16: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/16.jpg)
16
HybridCoilsDriverPickup/Reflec4on
• Havethewidestrangeofconfigura4ons.• Basicconfigura4onu4lizesanexcita4oncoilandanindependentsensing(pick-up)coilorsetofsensingcoils.
• Theexcita4onandsensingcoilscanbeincorporatedintoeachotherorseparatedbycertaindistance.
• Hybridcoilshaveendlessconfigura4onstomeetspecialneedsoftheinspec4onindustry,butarenotnecessarilythemostaffordablebreeds.
![Page 17: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/17.jpg)
17
HybridCoilsArrayProbes
AdvancedArrayTechnology-DetailedDisplay
![Page 18: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/18.jpg)
18
ECTvsRFTProbes
• MostECTProbesareBobbinProbesopera4nginthedifferen4almodes,selfcomparisonandexternalreference.
• SomeECTProbesfallintotheHybridcategoryforspecializedconfigura4ons.However,assensi4vityisgainedforonespecificdamagemechanism,othermechanismsmaybemissed.
![Page 19: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/19.jpg)
19
ECTvsRFTProbes
• RFTProbesareHybridProbes,(Driver/Pickup).
• RFTProbesfeaturealargeexcita4oncoiltogeneratethemagne4cfieldandapickupcoillocatedtwotothreetubediametersfromtheexcitercoiltodetectthechangesinfieldstrength.
![Page 20: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/20.jpg)
20
FillFactor
• FillFactor(FF)isthepercentagethetubeIDfilledbytheprobefortubinginspec4onsfromtheID.
• Whencalcula4ngfillfactor,usetheformula:FF=d2/D2wheredistheoutsidediameterofthecoilandDistheinsidediameterofthetube.
• ECTpreferredtohaveaFFof85%orbeYer.• RFTpreferredtohaveaminimumFFof70%.• SmallerFFvaluesmaybeacceptablebasedonsignal
responsefromacalibra4onstandard.• SameformulaforODencirclingcoils,reversethevalues.
![Page 21: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/21.jpg)
21
ECTApplica4ons
• Idealfornon-ferromagne4cmaterialssuchascopper,brass,copper-nickel,austeni4cstainlesssteelsandsimilaralloys.
• Reliesondirectcouplingbetweentheinspec4oncoilandthetestmaterial.
• CanbeusedonmildlypermeabletubeslikeMonelandferri4cstainlesssteelswiththeuseofmagne4cbiasprobes,to“zero”outthepermeabilityeffectsandlettheeddycurrentalterna4ngmagne4cfieldsrunfreetodotheirjob.
![Page 22: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/22.jpg)
22
RFTApplica4ons
• Idealforpermeableandhighlypermeablematerialslikeferri4cstainlesssteel,carbonsteelandsimilaralloys.
• Designedtoovercomethepermeabilityeffectsinferromagne4ctubing.
• Couplingtakesplaceindirectlythroughthegenera4onofeddycurrentsandtheirresul4ngmagne4cfield.
• RFTcanworkonnonpermeablematerialsbutitisnotasaccurateoreffec4veasconven4onalECT.
![Page 23: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/23.jpg)
23
Calibra4on
• AllECTandRFTequipmentmustbecalibratedonaregularbasistoensurefunc4onalityandsensi4vityareadequatefortheintendedinspec4on.
• TheASMEBoilerandPressureVesselCode,Sec4onV,ar4cle8andar4cle17specifytherequirementsforEddyCurrentTes4ngandRemoteFieldTes4ng.
• ASMEsec4onValsodefinescer4fica4onrequirementsforinspec4onpersonnel.
![Page 24: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/24.jpg)
24
SingleFrequencyvsMul4FrequencyTes4ng
• ForECT,themorefrequenciesthebeYer.• Eachfrequencyhasitsstrengthfordetec4onandallowsforsignal
mixingtoeliminateunwantedinterferenceliketubesupportplatesignals.
• Useofbothdifferen4alandabsolutemodesisalsorecommended.• Thevarietyofanumberofeddycurrentchannelsandmode
combina4onsallowsanextensiveanalysisofdefect(flaw)depthandcharacteriza4on.
![Page 25: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/25.jpg)
25
SingleFrequencyvsMul4FrequencyTes4ng
Morechannelsofdataensuretheanalystismakingavaliddefectcall,notiden4fyingandpluggingfalseindica4ons.
![Page 26: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/26.jpg)
26
SingleFrequencyvsMul4FrequencyTes4ng
• RFT,fewerfrequenciesthanECT.• RFTdoesnoteasilylenditselftomul4frequencyinspec4onand
signalmixing.• Duetothecharacteris4clowfrequencyopera4on,oneortwotest
frequenciesaretypicalforaRFTinspec4on.• Addingtoomanylowfrequencieshasanimpactonproduc4onby
reducingthesamplerateandinturnforcesslowerscanningspeeds.
![Page 27: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/27.jpg)
27
Conclusions
• ECTandRFTareeffec4vetoolsformeasuringtubeintegrity.• ECTwithmul4plefrequenciesfornon-ferromagne4ctubes.• RFTwithoneortwofrequenciesforferromagne4ctubes.• Armedwithdetailedinforma4onaboutaHTX’stube
integrity,plantmanagerscantakeproac4vestepstoeitherrepair,replaceorplugdamagedtubesbeforetheyfail,preven4ngaforcedoutage.
![Page 28: The Science Behind Eddy Current and Remote Field … · The Science Behind Eddy Current and Remote Field Tesng: for Condensers and Heat Exchangers Conco Services Corporaon 2](https://reader034.fdocuments.us/reader034/viewer/2022052319/5b60f1757f8b9a09498bd47d/html5/thumbnails/28.jpg)
28
Ques4ons
JamesKocherEddyCurrentLevelIIIACONCOSERVICESCORP.1-800-345-3476jkocher@conco.net