Palas Promo 2000 User manual

OperationManual
Light‐scatteringspectrometer
Promo®2000

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320102
CONTENTS:
1IMPORTANTNOTES!!!.......................................................................................................4
2INSTALLATIONANDFIRSTOPERATION.............................................................................5
2.1Mainsvoltagecheck......................................................................................................5
2.2Auxiliaryequipmentcheck............................................................................................5
3CONNECTINGTHESENSOR................................................................................................6
3.1Rearsideofthecontrolunit..........................................................................................6
3.2Frontsideofthecontrolunit.........................................................................................7
3.2.1Completeconnectionofthecontrolunit....................................................................8
3.3Connectionofthesensor..............................................................................................9
3.3.1Uppersideofthesensor............................................................................................9
3.3.2Bottomviewofthesensor.......................................................................................10
3.4Cleaningthesensor.....................................................................................................10
3.4.1Howtocleanthesensor..........................................................................................10
3.5Handlingoflightwaveconductorcables.....................................................................12
3.6Fibertest......................................................................................................................13
3.7Lampexchange...........................................................................................................15
3.8Lossofwarranty..........................................................................................................16
4CALIBRATIONOFTHESENSORWITHCALDUST1100.......................................................17
4.1HowtocalibrateyoursensorfortheselectedmeasurementrangewithCalDust1100?
18
4.2Calibrationofthevelocity:..........................................................................................19
5ENSURINGCORRECTTESTCONDITIONS..........................................................................20
5.1Measurementerrors...................................................................................................20
5.1.1Methodicerrors.......................................................................................................21
5.1.2Accidentalerrors.....................................................................................................21
5.1.3Agrosserror............................................................................................................21
5.2Importantcomparison................................................................................................22
5.3Erroridentificationofopticalmeasuringdevices.........................................................23
5.4Advantagesofcountingmeasuringprocedures...........................................................23
5.5Opticalparticlemeasurement.....................................................................................24
5.6Termsofopticalparticlemeasurement.......................................................................24
5.7Determinationofinteractionrelations........................................................................24
5.8Particlecharacteristics/Equivalentdiameter...............................................................25
5.8.1Particlecharacteristics............................................................................................25
5.8.2Equivalentdiameterof............................................................................................26
5.9Opticallimitationofthemeasuringvolume................................................................26
5.10Resolutioncapacityandclassificationaccuracy...........................................................27
6PARTICLEMEASUREMENTWITHPROMO®......................................................................28
6.1SpecialfeaturesofthePromo®system.......................................................................28
6.2Clearcalibrationcurve................................................................................................29

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320103
6.3Highresolutioncapacity..............................................................................................30
6.4Opticalmeasuringprinciple.........................................................................................31
6.5T‐aperturetechnology.................................................................................................32
6.6Borderzoneerror........................................................................................................33
6.7Impactofthedeviceparameters.................................................................................33
7OPTIONALEQUIPMENT:.................................................................................................35
CuvetteHeatingforwelas®digital1000,welas®digital2000,welas®digital3000,Promo®
2000,Promo®3000,welas®1000,welas®2000,welas®3000,PCS2010,PCS2000.................35
7.1Contents.....................................................................................................................35
7.1.1Function..................................................................................................................35
7.1.2Setupandcablingofthecuvetteheating.................................................................35
7.1.3MaintenanceandCleaning......................................................................................36
8TECHNICALDATA............................................................................................................39


OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320104

1IMPORTANTNOTES!!!
Pleasecheckimmediatelyafterunpackingtheinstrumentifthereareobvioustransportation
damages.Ifanydamagesoftheinstrumentarevisible,don’tconnectittomainsanddon’t
switchiton.Callthemanufacturertocheckiftheinstrumentcanbeoperatedsafely.

ItisessentialtoreadtheoperatinginstructionsthoroughlybeforeoperatingPromo®!!

Themanufacturerisnotliablefordamagescausedbyimproperoperating,incorrectcleaning
orthemeasurementofaerosolswithagasconditionorcompositiontheinstrumentisnot
specifiedfor.

Theinstrumentmayonlybeoperatedindryroomsunderatmosphericenvironmentalpressure
andatroomtemperature.
Themanufacturerwillnotbeliablewithregardtotheoperatingguarantee,ifoperatingtakes
placeunderdifferentenvironmentalconditions,suchascorrosiveorexplosiveenvironment,
electricorelectromagneticfields,operatingwithinareasofionisingradiation,withinareas
conductivetoshockorvibration.

Toswitch‐offPromo®,usethe"shutdown"button;Promo®shutsdownthenautomatically.
Donotswitch‐offthemainsswitch,beforetheoperatingsystemshutdownautomatically!!!

Formeasurementsinoverpressureandunderpressure,apressure‐resistantcuvetteisneeded.
Thepressure‐resistantcuvettecanbeinstalledsubsequently.Forthis,theopticsofthesensors
hastobere‐adjustedonthepremisesofPalas®.

Thepressure‐resistantcuvetteisabletoworkunderoverpressureupto10bar.

Formeasurementsinhightemperaturesthepressure‐resistantcuvettecanbeoptionally
heatedupto120°C.
Attention:Itisnotallowedtouseawelas®sensorwithintegratedheatingin
explosiveareas!!!

Promo®wasmanufacturedforthesystemvoltagedefinedinthecorrespondentorder.Please
checkifthesystemvoltageindicatedontheidentificationplatecorrespondstothesystem
voltageattheplaceofoperation.

Onlyuseoriginalspareparts!Pleasecontactthemanufacturertoorderspareparts.

Attention:Aerosolsmightbedangeroustoyourhealth.That’swhytheyoughtnottobein‐
haled.Itmightalsobenecessarytowearprotectiveclothes.Pleasepayattentiontothecorre‐
spondentstandardsandsafetyrules.

GeneralinformationonOpticalParticleCounters,suchasresolutioncapacity,detectionlimit
andcountingefficiency,canbefoundintheVDI‐guideline3489,Part3.

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320105
2Installationandfirstoperation

2.1 Mainsvoltagecheck

ThePromo®wassetbythemanufacturertothemainsvoltagerequestedintheorder.Pleasever‐
ify,ifthemainsvoltageindicatedonthetypelabelcorrespondstothemainsvoltageatthere‐
spectiveplaceoftheinstallation.

Themanufacturerisnotliablefordamagesresultingfromoperationwithimpropermainsvolt‐
age!!!


2.2 Auxiliaryequipmentcheck
Pleasealsoverifyimmediatelyafterunpackingtheinstrument,ifthedeliveryofallauxiliary
equipmentiscomplete.Besidesthesensorandthecontrolunit,thefollowingpartsshouldbe
available:

Mainscableforcontrolunit
2opticalfibres(standardlength:3m)
1tubeforconnectionofinternalpumptothesensor
1cableRS232forModbusinterface(9‐poleplug)
1operationmanual
1CDwithsoftware
onlywithPromo®H(heatableand/orpressure‐resistant):specialkeytoremoveholderofopti‐
calglassesfromcuvette
1tubeforcalibrationandmeasurements
CalDust1100forcalibration

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320106
3Connectingthesensor
3.1 Rearsideofthecontrolunit
Connectthecontrolunittothemainssupplyusingthemainscable.Thecontrolunitisswitched‐on
andswitched‐offwiththeon/offswitch.
Donotswitch‐offtheon/offswitch,beforetheoperatingsystemshutdownautomatically!!!

Thelampisswitched‐onbytheon/offswitch.Theoperationhourcounterrunsaslongthepower
ison.Thelamphasastandardlifetimeof2000hours.Incaseofalampexchange,thehourrecord‐
inghastobenoteddownasitcannotbereset.


RS232Modbus
interface
Filterunittoprotecttheinternal
pumpfromtheaerosol
Powerconnection
withon/offswitch
Operatinghourscounter
Outletforsamplingflow

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320107
3.2 Frontsideofthecontrolunit



Attention:
Uponconnectionoftheopticalfibres,pleasepayatallcostsattentionthattheconnectionatthe
controlunitcorrespondswiththeconnectionofthesensor.Ifthecablesareconnectedtothe
wrongsocket,theopticalandelectroniccomponentsoftheinstrumentwillbedamaged!

Takecare:
BEFOREswitchingonthesupplyunit,allopticalfibresmustbeconnectedcorrectlytothesupply
unitandtothesensor!
Especiallywhendisconnectingtheopticalfibrefromthedetectorofthesupplyunit,thesupply
unitmustbeswitchedoff!
Anyfailuretocomplywiththeserulescanleadtodamagesofopticalandelectronicpartsofthe
lightdetector.

Thesocketbelowtheamperemeterservestotestthelampefficiencyofthelampandthefunc‐
tionalityoftheopticalfibre.Todosuchatest,theopticalfibreneedstobeconnectedfromthe
lampoutlettothementionedsocket.Iftheammetershows>0,5mA,thelampandthefibreare
ok.

Thesuctionisdonebyafixedvolumeflowof5l/min.

Connectionofpump
Connectionofdetector
Additional
connection
forlampand
opticalfibre
check
Connectionoflamp
withyellowlabelling
(lampoutlet)
Touchdisplay
USBconnection

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320108
3.2.1 Completeconnectionofthecontrolunit
Attention:
Uponconnectionoftheopticalfibres,pleasepayatallcostsattentionthattheconnectionatthe
controlunitcorrespondswiththeconnectionofthesensor.Ifthecablesareconnectedtothe
wrongsocket,theopticalandelectroniccomponentsoftheinstrumentwillbedamaged!

Takecare:
BEFOREswitchingonthesupplyunit,allopticalfibresmustbeconnectedcorrectlytothesupply
unitandtothesensor!
Especiallywhendisconnectingtheopticalfibrefromthedetectorofthesupplyunit,thesupply
unitmustbeswitchedoff!
Anyfailuretocomplywiththeserulescanleadtodamagesofopticalandelectronicpartsofthe
lightdetector.

Carefullyplugthecablesintothesocketandfixbyturningthescrewednuttotheright.

Thetubeofthepumpmustbeconnectedtothemarkedpumpsocketandisfixedbyturningitto
thefront.
Pumpconnection
Detectorconnection
Lampconnection
Detectorconnection
Lampconnection
Pumpconnection
AnschlussFibreTest
Aerosolinlet

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV0010320109
3.3 Connectionofthesensor

3.3.1 Uppersideofthesensor
Attention:
Uponconnectionoftheopticalfibres,pleasepayatallcostsattentionthattheconnectionatthe
controlunitcorrespondswiththeconnectionofthesensor.Ifthecablesareconnectedtothe
wrongsocket,theopticalandelectroniccomponentsoftheinstrumentwillbedamaged!

Takecare:
BEFOREswitchingonthesupplyunit,allopticalfibresmustbeconnectedcorrectlytothesupply
unitandtothesensor!
Especiallywhendisconnectingtheopticalfibrefromthedetectorofthesupplyunit,thesupply
unitmustbeswitchedoff!
Anyfailuretocomplywiththeserulescanleadtodamagesofopticalandelectronicpartsofthe
lightdetector.

Carefullyplugthecablesintothesocketandfixbyturningthescrewednuttotheright.

Thetubeofthepumpmustbeconnectedtothemarkedpumpsocketandisfixedbyturningitto
thefront.
Aerosolinletconnection
Lampconnection
Detectorconnection
Opticalfibre
forlampcon‐
nection
Opticalfibrefordetector
connection

Connectionofthepump
tubeatthebottomsideof
t
h
e

se
n
so
r
Tubeofthepump
connection

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201010
3.3.2 Bottomviewofthesensor
Thetubeofthepump(plugconnection)ispluggedintothecorrespondentsocketatthebottom
sideofthesensor.
3.4 Cleaningthesensor
3.4.1 Howtocleanthesensor

First,removethepumptube(plugconnection)fromthesensorhousingatthebottomsideofthe
sensor(seepictureabove).Then,thetwohexagoncapscrewshavetobeloosened.Todoso,use
thecorrespondentwrench.

Afterthat,themeasuringvolumecanbetakenawayfromthesensor.Movetheaerosolguide
tubefromthebottomsideattheconnectionofthepumptubeslowlyupwards.
Pumptubewithconnection
forsensor
Connectionofthe
pumptubetothe
bottomsideofthe
sensor
Openthetwohexagon
screwsatuppersideof
thesensor

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201011
Cleantheopticalglassesinsidetheaerosolinletonlywithanopticalcloth.Nevertouchitwith
yourfinger.

Tocleantheaerosolguidetubeusepressurisedair.

Thesampleflowismeasuredanddisplayed.Thefilterelementinsidethefilterunitontheback
sideofthecontrolunithastobecleanedfromtimetotimeandshouldbechangediftheflowis
droppingbelowitsnominalvalue.

Attention:
Ifyouhaveasensorwithaspecialcuvette(welas®heatableand/orpressure‐resistant)youhaveto
removetheopticalglassesofthecuvettewithaspecialkeybeforeyoucleanthecuvettewith
pressurisedair.Cleantheopticalglassesofthecuvettealsoonlywithanopticalcloth.

Aerosolinlet–Usetheoptical
clothtocleanthetwooptical
glassesinside.
Aerosol guidingtube
Opticalclothtocleantheopti‐
calglasses

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201012

3.5 Handlingoflightwaveconductorcables



Whenremovingtheprotectivecappleaseholdthefibertotheplug.Donotholdittothefibercoatnorto
thefiberbendprotection!





Thefibermaynotbebenttooclosely.Themaximumbendingradiusof10cmshouldnotbeunder‐run.

Therightforcompensationdoesnotexistinthecaseofnaturalwearandtearordamagewhicharisesafter
thepassageofriskduetoincorrectorcarelesshandling,excessiveoperationaldemand,unsuitableequip‐
mentorduetospecialinfluences.


OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201013
3.6 Fibertest
Withthefibertestyouareabletocheckwhetherthelightwaveconductorcableisinpropercon‐
dition.Todosoyouhavetoconnectthecablebetweenthelightsourceoutputandthefibertest
input.


Attention:
Nevereverdirectlyconnectthelightsourceoutputwiththedetectorinput;thismaycausese‐
veredamagetothedetector!
PleaseuseonthetouchscreenthebuttonAccessoirs.
Thisviewisshownbypressingthebutton“suctionpump/signals/digitalIO"inthemenuoverview.



Promo®hasaninternalcontrolanddataacquisitioncard.Thiscardcanoptionallybeusedforthe
followingpurposes:controloftheinternalpump,recordingofanalogueanddigitalsignals.
Promo®canalsobeequippedwithtwotemperaturecontrollers.Additionally,Promo®continu‐
ouslymeasuresthevelocityoftheflow/particleswithinthesensor.

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201014
Displayofthemeasureddata
whicharemeasuredwiththe
internaldataacquisitioncard
(humidity,differentialpres‐
sure,temperature,absolute
pressure,sensorvolumeflow).
Statusofthedigitalinputsand
outputs.Twoanaloguesignals
arenotspecific.


Ifthefiberisingoodconditionyouwillhaveacertainvoltageindicatedbytheneedle.Thevalue
howeverisdependingonthequalityofthelightsourceitselfbutshouldneverthelessalwaysbe
largerthan1V.
Withthistestyoucanalsocheckthequalityofyourlightsource.


OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201015

3.7 Lampexchange

Thelampmustonlybechangedwhenitiscold.Ifthelampmoduleishotduetopreviousopera‐
tion,pleasewaituntilitiscooleddowntoambienttemperature.

Forexchangingthelampitisnecessarytoopenthe4screwsinthefrontplateofthelampmodule
ofthesupplyunit.Thenthemodulecanbepulledoutbyholdingitonthefibreconnectors.

Next,thelampconnectorisremovedbyturningitandpullingitofftheconnector.

The2screwsontheroundplatehavetobeopened.Turntheplateandremoveit.

Nowthelampcanberemovedcarefully.Pleasetakecarenottodamagetheglasspartofthe
lamp.

Insertthenewlampinthesameway.










4screwsinthe
frontplate
Pulloutlampmodule
bypullingonthefibre
connectors
Angleplug
Connectingscrewsof
lampsupportbracket

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201016
3.8 Lossofwarranty

Attention:
Iftheuserremovesthesealedscrews–eitheratthesideofthesensororatthesocketsofthe
opticalfibrestothesensor,thewarrantyisnotvalidanymore!!!!

Withindamagesmadebyimproperhandlingoftheheatableand/orpressure‐tightcuvette,espe‐
ciallybycleaningwithimpropersolventcleaning,e.g.Aceton,theuserwilllosethewarrantyof
theinstrument.









Sealedscrews
Inthispicturenotallsealedscrewscan
beseen

OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201017
4CalibrationofthesensorwithCalDust1100
Afterlampexchange,cleaningofthecuvetteorlongoperationperiods,thesensormustbere‐
calibratedwithregardtothedisplayedparticlesize.

Ascalibrationstandard,Palas®provideswiththedeliverythemonodispersecalibrationdust
“CalDust1100”.
Howtocalibrate:

Firstsetthenumberofintervalsperdecadeto32.
Startamanualmeasurementofparticlesizedistributionwith„CalDust1100“.

Forthispurpose,aflexibletubeisattachedwithafittingtotheaerosolinletofthesensor.

Byshakingofandknockingatthesuppliedcontainer“CalDust1100”,theparticlesinsidethecon‐
tainerarebroughtintoanairbornecondition.

Duringthemeasurement,holdthetubeintothecontainerwith“CalDust1100”.Nowtheparticles
aresuckedofffromtheairintothesensor.

Thisdisplayisshownbypressingthebutton„calibration“.


Thisviewisshownbypressingthebutton“calibration"intheview"sizerange/sensors".Assoon
asyoustartacalibrationtheoperatingmodusofthedeviceswitchesto"calib".Afteracalibration
youshouldchangethemodusbackto"auto","idle"or"manual".Thestatusofthedeviceisalso
recordedbythedata‐logger.


OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201018
Eachmeasurementrangeofeachsensorhastobecalibratedbyitsown.Acalibrationisdoneby
changingthephotomultipliervoltage(DAC)andtheparticlevelocity.Forthispurpose,twodia‐
gramsareshown:therawdatadistribution(amplitudesofthesignalsin256rawdatachannels)
andthetimedistribution(lengthofthesignals).Withtherawdatadistributiontheamplificationof
thephotomultipliercanbechecked,withthetimedistributionthevelocity.



Theautomaticallymeasuredchannelofthemaxi‐
mumoftherawdatadistribution.

Bypressingthisbutton,thevoltageforthepho‐
tomultiplieramplificationischanged.


Hereyoucanchangethepositionoftheredcross
withinthetimedistribution.Themaximumisnot
foundautomatically.Youhavetomovetheredcross
intotherightmaximum.Thepositioniscalculated
intothevelocity(measuredvelocity)byusingthe
geometricproportionsofthemeasuringvolume.

Bypressingthisbuttonyouchangethevelocity
calibrationforthecurrentsensorandmeasurement
range.

Thisboxshowsyouthematerialtobeusedforcali‐
bration(here:CalDust1100).Behindthedustmate‐
rialanumber(here:130)givesyoutheso‐called
targetchannelfortherawdatadistribution.
Youcanalsoseethevalueforthemeasuredvelocity
(relatedtothepositionoftheredcrosswithinthe
timedistribution)andthepresentvelocity(cali‐
bratedvelocity)thatiscurrentlyused.

4.1 HowtocalibrateyoursensorfortheselectedmeasurementrangewithCalDust1100?

Torunthecalibrationprocedure,connectaflexibletubetotheaerosolinletofthesensor.Hold
thefreeendoftheflexibletubeintotheopeningofthesuppliedCalDust1100containerafter
shakingthecontainertoloosentheparticlesandmakethemair‐borneinsidethecontainer.By
doingsoyouprovidethattheairwhichissuckedintothesensorisprimarilyfilledwithparticlesof
adiameterof0.85µm.Youmustnotshaketoostronglyasyoumustnothavemorethan10%
coincidentsignalsduringthecalibrationprocedure.
Calibrationofthephotomultiplier(PM)amplification:
TheobjectivethathastobeachievedherebyistoadjustthePM‐amplification(DAC)sothatthe
targetchannelofcalibrationmatchesthemeasuredmaximumoftherawdatadistribution.In‐
creasing/decreasingthePM‐amplificationbyincreasing/decreasingthevoltagewillmovethe
measuredmaximum(channelofcalibration)upward/downward.


OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201019
4.2 Calibrationofthevelocity:
Theobjectivethathastobeachievedherebyistochangethevelocity(presetvelocity)tothe
measuredvelocity.Youmeasurethevelocitybymovingtheredcrossintotherightmaximum
withinthetimechart.Ifthegasdensityofyourmeasuredaerosoldoesn'tchangeyoudonothave
tocalibratethevelocity.However,duringacalibrationprocedureoneshouldalwayscomparethe
oldparticlevelocitywiththenewparticlevelocityasalargedeviationgivesalsoanindicationfora
leakageinyoursuctiontubesoraproblemwithyoursuctionpump.Incaseyouhaveapressure‐
resistantsensor,e.g.welas®sensor2070P,orapressure‐resistantandheatablesensor,e.g.we‐
las®sensor2070HP,andifthepressureortemperatureconditionschange,youhavetocalibrate
andadjusttheparticlevelocityaswell.AlwaystrytocalibrateyoursensorwithCalDust1100at
thesamepressureandtemperatureconditionsasyoursubsequentmeasurements.However,
sometimesitisnotpossibletocalibrateyoursensorwithacalibrationdustatthesamethermo‐
dynamicconditions.Forthisreason,youcanalsoadjustthevelocitywithoutre‐adjustingthepho‐
tomultiplieramplificationandwithoutusingacalibrationdust.However,theparticleshavetobe
largerthan0.4µm.IfyouadjustthePMamplification,thevelocityshouldnotchange.Alternative‐
lyyoucanactivatetheautomatedgasdensitycorrection.



OPERATIONMANUALPROMO®2000
PALAS®GMBH,MARCH2010,VERSIONV00103201020

5Ensuringcorrecttestconditions

Incaseofdisadvantegeoustestconditions,themeasuringresult,i.e.thedeterminedparticlesize
distributionofthesinglemeasurements,canconsiderablydifferfromtheactualexistingvaluesin
theaerosolflow.

Therefore,pleasepayattentionto:
Representativesampletaking
Isokineticsampling
Minimalparticlelossesthroughtheaerosoltransport
Nocoincidenceerror

Pleasenote:Palas®regularlyofferstrainingcoursesaboutthesetopics.

Asabasicprinciple,thePromo®systemcanonlymeasureanddisplaydataithasbeenregistredin
itsopticalmeasuringvolume.Thatmeans,theaerosolsamplingflowshouldbeleadthereas
straightaspossible.
Therefore,pleasepayattentionto:

‐shorttubesfortheaerosol
‐ifpossible,metaltubes,innocaselongerplastictubes(highparticleseparationduetoelec‐
trostaticcharging)
‐verticalaerosolguiding,asbiggerparticles(>5µm)sedimentrespectivelytheaerosolsepe‐
rates
Asbasicprincipleofallcountingscatteredlightmeasuringtechnologies,justonesingleparticle
maybeintheopticallylimitedmeasuringvolumeofthesensoratthesametime.Thisduetothe
fact,thatthescatteredlightofthesingleparticleisbeingevaluatedforthedeterminationofthe
particlesize.

Ifmorethanoneparticlesareinthemeasuringvolumeatthesametime,theseparticlesare
measuredasone,i.e.theparticleisbeingmeasuredtoobigandthenumbertosmall.

Tomeasurecorrectly,onehastodilute.ThePalas®dilutionsystemshaveproventhemselvesin
practiceatthemarket.Ifrequested,theycanbeheatedandbeusedinoverpressureandunder‐
pressure.

Ifameasurementhasbeendonecorrectlywithadilution,thismeasurementsuppliesafinerpar‐
ticlesizedistributionandahigherparticleconcentrationasresult,comparedtoameasurementin
coincidence.Aseparationefficiencythatwasmeasuredincoincidenceisalwaysworsecompared
toonebeingmeasuredundercorrectconditions.

Theadvicesgivenherearesurelynotsufficienttoensureacorrectmeasurementinanycase.In
caseofparticularproblems,pleasecontactPalas®directly.

5.1 Measurementerrors