熱工儀表初選擇(Initialselectionofthermalinstrument)Multiple-choicequestionsWhentheelectricfieldisusedtodescribetheelectricfield,theelectricfieldoftheuniformelectricfieldis().Aandperpendiculartoeachother;Bandparalleltoeachother;Candpowerlinesintersect.Answer:B.Thecurrentflowingintotheconductoratthesametimeisequaltothecurrentflowingoutoftheconductor.Thisprincipleiscalled()principle.A,currentequivalence,B,currentinvariance,C,continuityofcurrent.Answer:C.theelectricfieldforcestheelectricchargefrom()toformcurrent.A,lowpotentialshifttohighpotential;B,highpotentialshifttolowpotential;C,translationdistance.Answer:A.intheoutercircuit,theelectricforceforcesthepositivechargefromthepath(from)toformthecurrent.A,lowpotentialshiftedtohighpotential;B,highpotentialshiftedtolowpotential;Cshiftedadistance.Answer:B.intheload,thedirectionofthecurrentandthedirectionofthevoltageisalways().A,opposite;B,consistent;C,arbitrary.Answer:B.inthepowersupply,thedirectionofthecurrentandvoltageis().A,consistent;B,opposite;C,same.Answer:B.PtypesemiconductorsandNtypesemiconductorsallhavecarriers,butthesemiconductordevicesthemselvesare().A,uncharged;B,positivelycharged;C,negativelycharged.Answer:A.theintrinsicsemiconductorsgeneratecarriersduetothermalmotion,leadingtothepresenceof()intheintrinsicsemiconductorsA,electroncarriers,B,holecarriers,C,electroncarriersandholecarriers.Answer:C.Ptypesemiconductorischaracterizedby()TheconcentrationofAandfreeelectronsisgreaterthantheconcentrationofholes;theconcentrationofBandholesisgreaterthantheconcentrationoffreeelectrons;theconcentrationofCandfreeelectronsisequaltotheconcentrationofholes.Answer:B.Accordingtotheminorerrorcriterion,themeasurementdataisusuallyadjustedaccordingtothe(allowed)errorofthemeasurement.A,0.05;B,0.1;C,0.5.Answer:B.theknowntruevalueis200degreescentigrade,themeasurementresultis202degreescentigrade,andtheabsoluteerroris().A,2,B,-2,C,2.Answer:A.Thestandardofmeasuringinstrumentsisusuallycalledqualityindex.A,performance;B,quality;C,manufacturingprocess.Answer:B.accordingtothetechnicalconditionsoftheinstrument,theallowablemaximum()iscalledthemaximumallowableerroroftheinstrument.A,basicerror,B,absoluteerror,C,relativeerror.Answer:B.accordingtotheprincipleofthedetectiondevice,itcanbeseenthatthemeasurementoftheelectromotiveforcebythebalanceandthemeasurementofelectromotiveforcewiththepotentialdifferencemeterbelongto()measuringmethod.A,minutedifferencemethod,Bandzerovaluemethod,Candindirectmethod.Answer:B.DDZ-IIImetertypeDKJinstrument,which'K'means().A,transferunit,B,executionunit,C,conversionunit.Answer:B.Thesignofthermodynamictemperatureis().A,K;B,T;C,t.Answer:B.Thethermometerthatisnotsuitableformeasuringfluctuationsatroomtemperatureis().A,pressurethermometer,B,rodthermometer,C,bimetallicthermometer.Answer:A.thesymbolofCelsiustemperatureist,whoseunitiscentigrade,andthesymbolofunitis().A,K;B,T;C,C.Answer:C.TherelationshipbetweenthetemperatureTandthethermodynamictemperatureTis().A,t=T+273.15;B,t=T-273.15;C,t=T-273.16.Answer:B.Thegasfilledthermometerismadeaccordingtothecharacteristicthatthegaschangeswiththetemperatureatthepressure.UndertheconditionsofAandconstantvolume,B,underanyconditions,C,andcertainenvironmentaltemperature.Answer:A.In198621,IPTS-68providedthermodynamictemperatureofthetriplepointofwater(is).A,273K;B,273.15K;C,273.16K.Answer:C.Inthefollowingkindsofthermalresistance,themostcommonlyusedstandardthermalresistanceinindustryis().AandGethermalresistance;Bandplatinumthermalresistance;CandNithermalresistance.Answer:B.1968IPTS-68provisionsofthetriplepointofwatervalue(Celsius).A,0,B,-0.01,C,0.01.Answer:C.TheresistancevalueofcopperresistorwithCu50is0.A,53;B,46;C,50.Answer:C.Theresistancevalueofthethermalresistanceat0degreescentigradeisPtlOO.A,46;B,100;C,50.Answer:B.twodifferentmetalconductorweldingclosedloopiscalledthermocouple,whenthetwoweldingendtemperatureisnotatthesametime,inthethermocouplecircuit().Adoesnotproduceanypotential;Bproducesthermalpotential;Cdoesnotproducecurrent.Answer:B.thermocouplethermoelectricpotential,ifkeepcoldendtemperatureconstant,thermocoupleproducethermalpotential0.Aisonlyrelatedtothetemperatureofthehotend;B,andinverselyproportionaltothetemperatureatthehotend;Cwillremainunchanged.Answer:A.trytodeterminethefollowingthermocouple,whichisnon-standardthermocouple(?).A,nickelchromium-nickelsiliconthermocouple;B,nickelcobalt-nickelsiliconthermocouple;Cironandconstantanthermocouple.Answer:B.trytodeterminethefollowingthermocouple,whichisastandardizedthermocouple(?).A,NiCrNiSithermocouple,B,NiCoNiSithermocouple,C,NiCoNiAlthermocouple.Answer:A.whenthethermocoupleoperatingtemperatureisdetermined,thethermocouplecoldjunctiontemperatureincreases,thermocouplethermoelectricpotential().A,increased;B,unchanged;C,decreased.Answer:C.TheaccuracyofthethermalpotentialmeasuredbytheDCpotentialdifferencemeterishigher,andtheinfluenceoftheexternalresistanceonthetemperatureischanged.A,mustconsider;B,neednotconsider;C,shouldconsider.Answer:B.Intheinternationalunitsystem,theunitofpressureisA,Pa;B,bar;C,kgf/cm2.Answer:A.theelasticelementissensitivetothechangeoftemperature,suchaselasticelementcontactwithhightemperaturemediumorbyhightemperatureradiation,elasticitywill(or),andproducemeasurementerror.A,deformation;B,increase;C,change.Answer:C.generallyusedUtubepressuregaugecolumnheightcannotexceed().A,1meters;B,1.5meters;C,2meters.Answer:B.liquidcolumnpressuregaugeindicationissmall,thereasonis().Aandpressurepipingarenotwellsealed;Bandguidepipeareblocked;Candairareblockedatoneend.Answer:A.thesinglecoilBourdontubepressuregauge,whenthepositivepressuremediumintothespringtube,thespringtubearclengthwill().A,variablelength,B,invariant,C,shorter.Answer:B.singlecoilBourdontubepressuregauge,whenthenegativepressuremediumintothespringtube,thecurvatureofthespringtubewillbe().A,smaller;B,larger;C,unchanged.Answer:B.whentheupperlimitofmeasurementislessthanorequalto0.25MPa,andusedtomeasurethepressureofgas,theapplicationofworkingmedium().A,air;B,water;C,transformeroil.Answer:A.Whenthepressuregaugeisinstalledabovethesamplingport,itszeropointisadopted.A,positivecorrection,B,negativecorrection,C,nocorrection.Answer:A.Checkthediaphragmdifferentialpressuretiming,andthestandardtableshouldbeselected().A,Utubedifferentialpressuregauge,B,pistonpressuregauge,C,singletubemanometer.Answer:A.Inthefollowingthrottlingparts,thestandardizedthrottlingdeviceis().A,VinChuliban,B,eccentricorificeplate,C,wingshapeddynamicpressuretube.Answer:A.inthe50?500mminsidediameterpipeonthethrottle,standardnozzleandstandardholeplate,standardnozzle(accuracy).A,lower,B,higher;C,thesameasthestandardorifice.Answer:B.Atpresent,mostofthemainsteammeasurementsareadoptedinthermalpowerplants.A,standardorificeplate,B,standardnozzle,C,venturinozzle.Answer:B.Inthevariouselasticdifferentialpressuregauges,thetraveloftheelasticelementsofthedoublebellowsdifferentialpressuregauge.A,minimum,B,larger,C,max.Answer:C.thepressuregaugesignaltubeselectionrequirementsistoensurethatthepipelineisnotblocked,noleakage,delaytimeissmall,whenthesignalpipelineislessthan20meters,itsinnerdiametershouldbe().A,nolessthan3mm;B,nolessthan5mm;C,nolessthan8mm.Answer:A.theselectionofpressuregaugesistoensuretheaccuracyofthemeasurement,thepressureshallnotbelessthantheupperlimitoftheselectedpressuregauge().A,1/4;B,1/3;C,1/2.Answer:B.Inthefollowingflowmeter,theflowmetermeasuringvolumebyvolumemethodis().A,turbineflowmeter,B,Rootsflowmeter,C,electromagneticflowmeter.Answer:B.Theflowmetercommonlyusedformeasuringfuelquantityinthermalpowerplantis().A,differentialpressureflowmeter,B,rotorflowmeter,C,targetflowmeter.Answer:C.Whentheboilerisinnormaloperation,thewaterlevelofthemicawaterlevelgaugeonthedrumiscomparedwiththeactualwaterlevelinthedrum.A,higher;B,equal;C,low.Answer:C.Thewaterlevelcontaineroftheelectriccontactwaterlevelgaugemustbeinstalledvertically.Themiddlepointofthecylinder(zerowaterlevel)andthenormalwaterlevelofthedrum().A,atthesameheight;B,higherthan50cm;C,comparedwithlow50cm.Answer:A.Theinsulationresistancemustbemeasuredbeforetheelectrodeoftheelectriccontactwaterlevelgaugeisused,andthevalueoftheinsulationresistanceshouldbegreaterthan().A,20M;B,50M;C,100M.Answer:C.Thegaswillbemagnetizedbythemagneticfieldinthemagneticfield,andthedegreeofmagnetizationcanbeexpressedbythemagnetization.Themagnetizationisproportionaltothemagneticfieldintensitythatcausesthemagnetization.A,inverseratio,B,directratio,C,nonlinearity.Answer:B.therelationshipbetweenoxygenconcentrationpotentialandoxygenpartialpressureisnotlinear,but()relation.A,nonlinearity,B,logarithm,C,exponent.Answer:B.theamountofthedesiredquantityshouldbecalled().A,targetvalue;B,regulationquantity;C,givenvalue.Answer:C.Thevariousreasonscausingthedeviationfromthegivenvalueintheproductionprocessarecalled().A,interference,B,perturbation,C,deviation.Answer:B.Themechanismthatplaysaregulatoryroleintheregulatorysystemiscalled().A,disturbancemechanism,B,regulatingmechanism,C,actuator.Answer:B.Thesystemisnotcontrolledbytheoperatingpersonnelandcanproduceexternaldisturbances.A,disturbancemechanism,B,regulatingmechanism,C,actuator.Answer:A.thedisturbanceoccurringintheclosedloopsystemiscalled().A,internaldisturbances,B,externaldisturbances;Candbasicdisturbance.Answer:A.thedisturbanceoccurringoutsidetheclosedloopsystemiscalled().A,internaldisturbances,B,externaldisturbances,C,basicdisturbances.Answer:B.asameansofadjustmentofdisturbance,knownas().A,internaldisturbances,B,externaldisturbances,C,basicdisturbances.Answer:C.Intheblockdiagram,thearrowpointingtotheboxrepresents(),whichisthecauseofthechange.A,inputsignal,B,outputsignal,C,regulatedsignal.Answer:A.Intheblockdiagram,thearrowawayfromtheboxrepresents(),whichistheresultofthechange.A,inputsignal,B,outputsignal,C,disturbancesignal.Answer:B.Intheautomaticregulationsystem,theequilibriumstatethattheamountofregulationdoesnotchangewithtimeiscalledthesystem.A,dynamics,B,steadystate,C,staticstate.Answer:B,C.Theboilerregulatesthesteamtemperaturefromthefluegassidethrough().A,changetheburnerswingangle;B,temperaturereducer;C,pressurereducer.Answer:A.Thesteamtemperatureisregulatedbysteamfromthesteamsideoftheboiler.A,temperaturereducer,B,pressurereducer,C,changeburnerswingangle.Answer:A.TheboileraccidentwatergateisopenedwhenthewaterlevelishigherthantheIvalue.A,drum;B,C,highpressuredeaerator.Answer:A.Whentheboilerloadincreases,thesteamtemperatureattheoutletofthesuperheater.A,unchanged;B,decreased;C,increased.Answer:C.theturbinethroughthechange(),controltheamountofsteam,soastocompletethetaskofspeedregulation.A,rotorspeed;B,controlvalveopening;C,exhaustcheckgateopening.Answer:B.Whentheboilerisinnormaloperation,thewaterlevelofthedrumisshowntobehigherthanthatoftheactualwaterlevel.A,equal;B,higher;C,lower.Answer:C.Thetaskofautomaticpressureadjustmentofdeaeratoristocontrolthepressureindeaeratortobesaturatedpressure,andtoensurethatfeedwaterisheatedtosaturationtemperature,soastoimprovethedeoxidizationeffect.A,watersupply;B,steamspace;C,steamwatermixture.Answer:B.Highpressureheatersinthermalpowerplantsareheatedbysteamextractionfromsteamturbines.A,watersupply,B,condensedwater,C,hydrophobic.Answer:A.Whenthedrumisinnormaloperation,itswalltemperatureshouldbe().A,upperwalltemperatureishigherthanthelowerwalltemperature;B,upperandlowerwalltemperatureareequal;C,lowerwalltemperatureishigherthantheupperwalltemperature.Answer:A.becausethesuperheaterisaheatexchanger,itsoutletsteamtemperaturereflectstherelationshipbetweentheheatandheatofthesteam.Aabsorptionfromthefluegasside;B,evaporationheatingsurfaceabsorbheat;C,boilerheatstorage.Answer:A.whentheheatingsurfaceslaggingorashaccumulationistoolong,sothattheconvectionsuperheaterabsorbheatincrease,superheatedsteamtemperature().A,decrease,B,increase,C,unchanged.Answer:B.whenthefeedwatertemperaturedecreases,iftheamountoffuelremainsunchanged,theevaporationwillbereducedaccordingly,sothesuperheatedsteamtemperature().A,unchanged;B,decreased;C,increased.Answer:C.whenthepulverizedcoalisthickenedortheburneranglerises,theflamecenterpositionmovesupward,sothatthesuperheatedsteamtemperature().A,unchanged;B,decreased;C,increased.Answer:C.ifthedecayrateisequalto0,thentheregulationprocessis(process).A,equalamplitudeoscillation,B,divergentoscillation,C,nonperiodic.Answer:A.ifthedecayrateisequalto1,thentheregulationprocessis(process).A,equalamplitudeoscillation,B,divergentoscillation,C,nonperiodic.Answer:C.ifthedecayrateis<0,thentheregulationprocessis(process).A,equalamplitudeoscillation,B,divergentoscillation,C,nonperiodic.Answer:B.Itcanreducethedynamicdeviationoftheregulatedquantityintheadjustmentprocessandadjusttheprocesstime.Aandproportionalaction;Bandintegralaction;Canddifferentialaction.Answer:C.Thestaticdeviationcanbeeliminatedsothatthedynamicdeviationandtheregulatingtimeoftheregulatedamountintheregulationprocessareincreased.Aandproportionalaction;Bandintegralaction;Canddifferentialaction.Answer:B.Themostbasicregulatingfunctioninallkindsofregulationis().Aandproportionalaction;Bandintegralaction;Canddifferentialaction.Answer:A.waterbalancecontainerbeforethedoortransverseinstallation,inordertoavoidthevalve()andaffecttheaccuracyofthemeasurement.A,accumulationofemptybubbles,B,liquidleveldifference,C,throttlingeffect.Answer:A.Thedifferentialpressuretransmitterwithoutputsignalof4-20mAisusedasthedrumleveltransmitter.Whenthewaterleveliszero,thetransmitteroutputis().A,4mA;B,12mA;C,0mA.Answer:B.Themostcommonlyusedflowmeasuringinstrumentinthermalpowerplantis().A,volumeflowmeter,B,targetflowmeter,Canddifferentialpressureflowmeter.Answer:C.Throttlingdeviceusedinsteamflowmeasurementinthermalpowerplantiswidelyused.A,nozzle;B,KongBan;C,dynamicpressuretube.Answer:A.Thefeedwaterregulationsystemofhightemperatureandhighpressureboilergenerallyadopts()regulatingsystem.A,singleimpulse,B,doubleimpulse,C,threeimpulse.Answer:C.itcaneliminatethebadinfluenceof"falsewaterlevel”,butcannotquicklyeliminatethespontaneousdisturbanceofwatersupplyflowandtimelyreflecttheregulationeffectis()watersupplyregulationsystem.A,singleimpulse,B,doubleimpulse,C,threeimpulse.Answer:B.inthemainsteamtemperatureautomaticregulationsystem,thetemperaturetransmitterzeromustbecarriedout(),inordertoimprovetheaccuracyofmeasurement.A,positivemigration,B,negativetransfer,C,nonmigration.Answer:A.Itisbettertomeasuretheflowrateofboilerairpipe.Aandrootsflowmeter;B,KongBan;C,wingshapeddynamicpressurepipe.Answer:C.aftertheblowerortheinduceddraftfaniscutoff,themainfueltripactionshouldbedelayed,andthebaffleofthetripfanshouldbeslowlyopened,andtheopeningstateshouldbenolessthan().A,5min;B,lOmin;C,15min.Answer:C.Atpresent,thesoundsystemwidelyusedinthermalpowerplantsis().AandACrepeatsoundsignalsystem;BandDCrepeatsoundsignalsystem;CandACnonrepetitivesignalsystem.Answer:A.inthepowerplantbetweenthemaincontrolroomandthesteamroom,boilerroom,touse()totransferafewbutveryimportantoperationalterms,ortoinformeachotheroftheunit，soperatingstate.A,contactsignal,B,advancesignal,C,accidentsignal.Answer:A.whenthepressureincreasestotheIIvalue,stoppartofthepowderoropen().A,safetydoor,B,airexhaustvalve,C,steamextractioncheckgate.Answer:B.Thepowerofthepulsedelectromagneticsafetydooris().A,compressedair;B,steam;C,pressurewater.Answer:B.Therelayisarelaythatcanbeautomaticallyswitchedbymeansof(or)otherphysicalquantities.A,mechanicalforce,B,electromagneticforce,C,current.Answer:B.Inthestart,stopandoperationoftheturbine,whentheaxialthrustoftherotoristoolargeortheoiltemperatureistoohigh,theoilfilmisdestroyed,Wujinthrustpadwillbedestroyed,causingtheturbinestaticpartoffriction,aseriousaccident,therefore,set(device).Aandaxialdisplacementmeasurementprotection;Bandrelativeexpansionprotection;Candabsoluteexpansionmeasurementprotection.Answer:A.whenthewaterlevelisuptoIII,theprotectionsystemaction().A,sendoutthewarningsignal;B,opentheaccidentwatergate;C,sendoutthestopsignal.Answer:C.99.Thefurnaceflameisdark,theprotectionsystemsendsout(),causestheoperatortopayattention,andtakesthemeasuretoeliminatethebreakdown.A,advancesignal,B,connectionsignal,C,accidentsignal.Answer:A.100,themostcriticalpartofflamedetectiondeviceisthedetectionelement(alsoknownastheprobe),theuseofittochangethestrengthofthefurnaceflameinto().electricalsignals;B,switchingsignals;C,"0"or".Answer:A.Thefollowingrelay,()istheelectricquantityrelay.A,pressurerelay,B,temperaturerelay,C,timerelay.Answer:C.thefollowingrelay,()isnonelectricalrelay.A,pressurerelay,B,currentrelay,C,liquidlevelrelay.Answer:C.Thefunctionofthetorquelimitingmechanismistocutoffthemotoroperatingcircuitthroughthemicroswitchwhentheoutputtorquereaches()therequiredvalue.A,bigvalve;B,smallvalve;C,GuanYanvalve.Answer:C.thecablelayinginthebracketorbridge,requireneatarrangement,reducewithotherequipment,pipelinecross,andcanpreventcablewithstand().A,excessivetensileortransitionalbending;B,mechanicaldamage;C,excessivecrossandwaste.Answer:A,B.theuseofelectrichammerorimpactdrillhole,drillheadshouldbedrilledintheopenintheface,(to).A,avoidemptyhit;B,speedup;C,preventdeviation.Answer:A.flamemonitoringdevice,istheuseofultravioletphotosensitivetubeintheultravioletsignalinto()controlsignal.A,current;B,voltage;C,resistance.Answer:B.intheoperationofthesteamturbine,theaxialdisplacementoftherotorishowtomovethetransmitter:().A,movealongwiththerotor;B,movealongwiththecylinder;C,donotmove.Answer:B.inthepowerproductionprocess,sometimeshopethattherotatingmachineryonlyinacertainrangeofoperation,whichcanbeused()tocontrol.A,controlswitch,B,button,C,strokeswitch.Answer:C.Themostfrequentlyusedrelayinthethermalcontrolis0relay.A,voltage;B,current;C,electromagnetism.Answer:C.Itisgenerallyusedtocontroltheopeningorclosingoftheelectricdoor,andtheconnectionanddisconnectionoftheinterlockingcircuit.A,strokeswitch,B,controlswitch,C,magneticstarter.Answer:B.Therelaythatcanreflectthepolarityoftheinputsignalis().A,dryreedrelay,B,polarizationrelay,C,intermediaterelay.Answer:B.Therelaythatusesthemeasuringelementtoheattoacertaintemperatureis().A,temperaturerelay,B,thermalrelay.Candpolarizationrelay.Answer:B.whenthefurnaceflamebecomesdark,theprotectionsystemaction().A,stoppingpowderfeedingmachine,B,oilfeedingandcombustionsupporting,C,stoppingfurnace.Answer:B.()isanimportantdeviceforhighboilerpressureprotection.A,airexhaustvalve,B,safetydoor,C,steamextractioncheckgate.Answer:B.whenthewaterlevelishighII,theprotectionsystemaction().A,warningsignal,B,emergencyshutdowngate,C,stopfurnace.Answer:B.whenthewaterlevelislowIIIvalue,Protectionsystemaction().A,sendalarmsignal;B,openandstandbytowatergate;C,stopfurnace.Answer:C.Thethermalsignalsusedtorepresentthestateoftheequipmentinthethermalsystemarecalled().A,trendalarmsignal,B,statesignal,C,overlimitalarmsignal.Answer:B.()usedtoinformtheoperatingpersonnelinthe