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EN Instruction Manual BOD-System Oxi700
EN Instruction Manual
BOD-System Oxi700
Content
1. Thesystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.1 Principleofthemethod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.3 Illustrations/Equipmentsupplied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Themethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.1 Biochemicaloxygendemand(BOD). . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.2 BODsensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.3 Principleofmeasurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.1 Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.2 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.3 Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.4 Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.5 InitialSetUp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.6 Switchingon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.7 Switchingoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.8 Readingstoredvalues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.9 Readingactualvalues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.10 Startingmeasurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.11 Parametermenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.11.1 Settingdateandtime. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.11.2 Autostart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.11.3 Autoduration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.11.4 Replacingbatteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.12 Datatransfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.13 Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4. BODmeasurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.1 Samplevolume. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.2 Preparingthewatersample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5. Interpretationofresults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Checkingthemeasurementsystem . . . . . . . . . . . . . . . . . . . . . . . . 19
7. Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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Content
8. Inductivestirringsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208.1 Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.1.1 Correctuse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.1.2 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.2 Safetyrequirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228.3 Equipmentdescriptionandfunction. . . . . . . . . . . . . . . . . . . . . . . . . . . 248.4 SetUp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248.5 Magneticstirringrods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258.6 Stirring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258.7 Maintenanceandcleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268.8 Troubleshouting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268.8.1 Thestirringrodrotatesunevenly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268.8.2 Thestirringrodswervesbackandforth . . . . . . . . . . . . . . . . . . . . . . . . 26
9. Technicaldata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279.1 BODsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279.2 Inductivestirringsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
10. Accessoriesandspareparts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
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1. TheSystem
1.1 Principleofoperation BOD ismeasuredby thepressuredifferencewithinaclosedsystem (respirometric
BOD).TheintegratedmemorysavesaBODvalueautomaticallyevery24hoursforatestperiodofmorethan3days.
1.2 Applications DeterminationofBOD5andBOD7,OECD301F/biologicaldegradability.
Otherbio-technologicalapplicationsinaqueoussolutions.
1.3 Illustrations/Equipmentsupplied
■ 1xBODmeasuringdevicewithintegratedbottlerack
■ 6xBODsensor(materialABS)*
■ 6xBODbottles
■ 6xsealcups(Gasket)
■ 6xmagneticstirringrods
■ 1xstirringsystemdrive
■ 1xstirringsystemcontroller
■ 1xnitrificationinhibitor(ATH)
■ 1xpotassiumhydroxidesolution(KOHsolution,45%)
■ 2xoverflowmeasurementflasks(157mland428ml)
■ 1xinstructionmanual
*beforeusingnotaqueoussolutionsprooftheresistanceofthematerialagainstthesample
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2. TheMethod
2.1 BiochemicalOxygenDemand(BOD) Thebiochemicaloxygendemand(BOD)ofwastewater,industrialeffluentsandsurface
waterisanexpressionfortheamountofoxygenconsumedbythedecompositionoforganicmatterinabiochemicalprocess.
2.2 PrincipleofMeasurement TheBODsystem,consistingofthesamplebottleandtheBODsensor,representsa
closedsystem.Inthebottle,abovethesampleitself,isadefinedvolumeofair.DuringtheBODmeasurement,thebacteriainthesampleconsumethedissolvedoxygeninthesample.Thisisreplacedbyoxygeninthebottleabovethesample.Thecarbondioxidereleasedatthesametimereactwiththepotassiumhydroxideinthesealgasket.Thisgeneratesadecreaseinpressurewithinthesystem.ThisismeasuredbytheBODsensoranddisplayedasaBODvalueinmg/lO2.
2.3 PreparingtheSample/BriefSummary• Estimatethemeasurementrangeandselectthevolumeforthesample(4.1).
• Carryoutnecessarypre-treatmentofthesample(e.g.,settingthepHvalue;filtering;etc.)(4.2).
• Measurethevolumeofthesampleprecisely,usingtheoverflowmeasurementflaskandtransferittotheBODbottle,withtheaidofafunnel.Ifnecessary,addnitrificationinhibitor(4.1).
• Insertthemagneticstirringrod.
• Place3-4dropsofKOHsolutionintothesealgasket.Theninsertthegasketintheneckofthebottle.
• ScrewtheBODsensorstothesamplebottles.
• Placethebottleinthebottlerack.
• Startthemeasurement(3.10).
• Incubatethesampleinaccordancewiththeinstructions(e.g.BOD5for5daysat20°C)
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3. Operation
3.1 Keys
Key Functions
OnOff
• Switchestheunitonandoff(automaticswitchoffapprox.45secafterlastoperation)
• Quitssub-menus• Breaksoffoperations
START • SetUpofmeasurements
READ • Readingofacurrentvalueforaselectedposition(doesnotstorevalue!)
+ • Increasesparameter/figure
- • Reducesparameter/figure
ENTER• Confirmsinput• Switchestoothersectionsinmenus
• Headkey:selectsthepositionrequired
• Head LED : indicates the position which has been selected
1 23 45 6
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3.3TechnicalTerms
Finishedhead Aheadwhichhascompleteditsseriesofmeasurements
FreeheadAheadwheretheseriesofmeasurementshasbeenfinishedandatleastonefigurehasbeendisplayedinread-outmode(see„Readingoutstoredvalues“).
Startvalue
BODmeasurementisbasedonadifferenceinpressure.Whenameasurementisstarted,theinitialpressureisstoredasthestartvalue.BODfiguresarethenobtainedbymeasuringcurrentpressurevaluesandcalculatingtheBODfromthedifferencebetweenthetwo.
DisplaymodeOperatingstatus,inwhichthe„OxiDirect“displaysthelaststoredvalueandtheselectedmeasurementperiodforahead
Read-outmodeOperatingstatus,inwhichallthestoredvaluesforaheadcanbedisplayed,togetherwiththeassociatedtimeofmeasurement
Startmode Operatingstatus,inwhichmeasurementscanbestarted
BackgroundmodeThe„OxiDirect“carriesoutsporadicmeasurementsindependently.Theindicationisalineinthecentreoftheupperdisplay.Donotchangeanybottleswhilethisisinoperation.
3.2OperatingModes
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3.4DisplaysandtheirMeanings
LEDs Meaning Actionrequired
LEDsIndicatethepostionwhichhasbeenactivated
LEDislit Measurementiscomplete
LEDflashes Measurementisnotyetcomplete
Dispay Meaning Actionrequired
LobAt
Batteryisnearlyempty• Changebatteries(see„Changing
theBatteries“-3.11.4)
LoAd„OxiDirect“hasnotfoundaheadatthisposition
• Checkwhetherthereisaheadattheselectedposition
• Checkcontactsbetweenheadandrack
xd
Theunitisin„displaymode“.Theupperdisplayshowstheselectedmeasurementperiod.Thelowerdisplayshowsthelastvaluewhichhasbeenstored
dx
hx
Theunitisin„read-outmode“andshowsthestoredvalueforday‚d‘/hour‚h‘(x=1...28daysor1...48hrs.)
UFLThevaluesarebelowthepermittedmeasurementrange(belowzero)
• Checkthattheflaskisfullysealedwiththemeasurementhead
• Checkthetemperature
OFLThevaluesareabovethepermittedmeasurementrange
• Checkthetemperature
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Dispay Meaning Actionrequired
F1 Nomeasurementfigurepresent
F2No„start-value”present,sonoactualBODvaluecanbecalculated
see„Autostart“
F120 Anerrorhasoccurredon„Start“
Bottlesmustnotberemovedduringthe„start“process.Also,positionsmustnotbechangedduringthe„start“process
SetDAteDuringinitialsetuporafterpowersupplyfailsthetimeanddatemustbereset
See„SettingTimeandDate“(parametersmenu3.11.1)
SrtundLoAdTheunithasnotlocatedaheadatthepositionwhichhasbeenselected
• InsertabottlewithheadandpresstheOn/Offkey;or:
• Selectanotherposition.Theunitwillchangeto„DisplayMode“
SrtundDELThedatafortheheadattheselectedpositionhavenotyetbeenreadout.
• Tocontinuethe„start“process,pressthe„Enter“key.(NOTE:Alldataonthisheadwillbedeleted!)
• Toquitthe„start“process,presstheOn/Offkey.Theunitwillthenchangeto„DisplayMode“
EndundLiFE
Theelectronicsontheheadcannotstoreanymorevalues(thisshouldnotoccurinnormaluse).
Thevaluesmostrecentlystoredcanbereadout.Theheadmustbereplaced.
3.4DisplaysandtheirMeanings
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3.5InitialSetUpThebatteriesarepackedseparatelywhentheunitisdelivered.Ifnecessary,removeallthebottlesfromtherack,turntherackandopenthebatterycompartment.Installthethreealkali-manganesebatteries(C/LR14)inthebatterycompartment(checkingforcorrectpolarity).Theunitshouldthenswitchonautomaticallyandthedisplaywillshow„SetDAte“.Ifnecessary,switchtheuniton.Setthedateandtime(seetheparametersmenu3.11.1).
3.6SwitchingonTheunitisswitchedonwiththeOn/Offkey.The„OxiDirect“willactivatetheleftpositioninthefront(position1)andwillindicatethisbytheLED,whichwillbepermanentlylit(=measurementiscomplete)orbyflashing(=measurementinprogress).
Ifthereisnoheadatthisposition,the„OxiDirect“willdisplay„LoAd“.
Whenitisswitchedon,the„OxiDirect“isin„DisplayMode“,inwhichthelaststoredvalueandtheselectedmeasurementperiodaredisplayed(oradisplayasshowninTable3.4).Forexample:
Meaning
Upperdisplay 5d days 5days‘BOD
Lowerdisplay 178 mg/l 178mg/lO2asthelaststoredvalue
3.7SwitchingoffTheunitisswitchedoffbypressingtheOn/Offkey.Iftheunitisnotin„DisplayMode“,theOn/Offkeymustbepressedseveraltimesinordertoswitchoff.
Duringtheswitching-offsequencetheupperdisplaywillshow„OFF“andalinewillthenappearinthemiddleofthedisplay.Duringthisperiod,donotremoveanybottlesfromtherack,orchangeplaces,oraddbottles,orpressanyotherkeys.Theswitching-offsequenceiscompletewhenboththedisplaysareblank.Atthispoint,waitafurther2secondsminimumbeforeswitchingonagain.
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3.8ReadingoutstoredvaluesOncetheunitisswitchedon,pressthekeytoselectthepositionrequiredandconfirmbypressingthe„Enter“key.Theunitwillswitchto„DisplayMode“forthisposition.Theupperdisplaywillnowshowthemeasurementtimeandthelowerdisplaywillshowthevaluewhichhasbeenstored.
Theunitalwaysstartswiththefirstvalue–i.e.,withaBOD-5set-upitwillstartwithday1(d1),forexample:
Upperdisplay d1 days Valueofthefirstday
Lowerdisplay 147 mg/l 147mg/lO2asthevalueforthefirstday
The„+“and„-“keyscanbeusedtodisplayotherstoreddataforthisposition.
Theheadkeyscanbeusedtoselectanotherposition.Ifthispositionisvacanttheunitremainsin„read-out“modeandshows„LoAd“.Placeaheadinthispositionforreadingoutthestoredvaluesorselectanotherposition.
PressingtheOn/Offkeywillcausetheunittoquit„read-out“modeandgoto„displaymode“.
Forameasurementperiodofoneor2days(BOD-1andBOD-2)themeasurementtimeisstatedinhours.Formeasurementperiodsexceeding2days(BOD-3,BOD-4...)itisshownindays.Thehoursareshownintheformof„hxx“sothelatestfigureforaBOD-2,forexample:
Upperdisplay h1 hrs Valueofthefirsthour
Lowerdisplay 178 mg/l 178mg/lO2valueforthefirsthour
3.9ReadingoutthecurrentvaluesOncetheunitisswitchedon,pressthekeyforthepositionrequired.Thenpressthe„READ“key.Thecurrentvaluewillthenanddisplayed.
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3.10Startingmeasurement
Startinganewmeasurementwilldeleteallstoreddatafromthehead!
Placeapreparedbottleinavacantpositionoftherack.Switchontheunitandpressthecorrespondingheadkeytoactivatethisposition.
Pressingthe„Start“keywillnowstartthemeasurementforthisbottle.Whenthe„Start“keyispressed,theunitchangesto„StartMode“andwilldisplaythelastselectedrangeusedforthishead,withthesamplevolumerequired(specialcasesaredescribedlaterinthissection).Thedisplaywillflash.Forexample:
Upperdisplay 157 ml 157ml(samplevolumerequiredforthemeasurementrange)
Lowerdisplay 400 mg/l Rangeupto400mg/lO2
Variousactionsarenowpossible:
• The„+“and„-“keyscanbeusedtochangethesamplevolumeandthemeasurementrange.
• Pressingthe„Enter“keywillselectthedisplayedsamplevolume/rangeandthe„start“processwillcontinue.
Theunitcheckswhether„Autoduration“isactive.Ifso,theunitwillautomaticallyselectthespecifiedmeasurementperiodandwillactivatethemeasurement.Themeasurementperiodisnotdisplayed.If„Autoduration“isnotactive,theunitwilldisplaythelastmeasurementperiodwhichwasused(thedisplaywillflash).Forexample:
Upperdisplay 5d ml 5days‘BOD(BOD-5)
Lowerdisplay Thelowerdisplayisblank
Variousactionsarenowpossible:
• The„+“and„-“keyscanbeusedtochangethemeasurementperiodinone-daysteps.
• Pressingthe„Enter“keywillselectthedisplayedmeasurementperiodtobeusedandtheunitwillstartthemeasurement.
Whiletheunitattemptstostartthemeasurement,thedisplayswillshow„0.0.0“and„0.0.0.0“(flashing).Timecanvary.
Whentheunithassuccessfullystartedthemeasurementthedisplayswillshow„000“and„donE“.
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3.11ParametersMenuPressthe„ENTER“keyandholditdepressed.SwitchontheunitwiththeOn/Offkey.Allowthreedecimalpointsinthelowerdisplaytoflashfor3secondsandthenreleasethe„ENTER“key.Theunitisnowintheparametersmenu.The„+“and„-“keyscannowbeusedtoselectbetweentheDate/Time,„Autostart“,„Autoduration“and„ChangeBatteries“menus.Pressingthe„ENTER“keywillgiveaccesstothesub-menuwhichisselected.QuittheparametersmenuwiththeOn/Offkey.Theunitwillreturnto„DisplayMode“.
3.11.1SettingtheDateandTimeConfirm„Set“„DAtE“bypressingthe„ENTER“key.Theunitwilldisplay„dA“andtheyearwhichiscurrentlyset.Pressthe„ENTER“key.Theunitdisplays„dA“andnowshowsthedatewhichiscurrentlysetintheformof„MM.TT“,where„MM“indicatesthemonthand„TT“indicatestheday.
Pressthe„ENTER“key.Theunitdisplays„ti“andthetimeintheformof„hh.mm“where„hh“indicatesthehoursand„mm“indicatestheminutes.Pressthe„ENTER“key.Theupperdisplayflashesandshows„JJ“andthelowerdisplayshowstheyearinfigures.Theyearcanbechangedwiththe„+/-“key.Pressthe„ENTER“key.
Inthiswayitispossibletoresetthefiguresforthemonth(thedisplayshows„Mo“),theday(thedisplayshows„dd“),thehour(thedisplayshows„hh“),thetensofminutes(thedisplayshows„M“)andthesingleminutes(thedisplayshows„m“).Eachentrymustbeconfirmedbypressingthe„ENTER“key.Finally,pressthe„ENTER“keyoncemoretoadoptthefigureswhichhavebeenset.Theunitsetstheinternalclocktothesefiguresand(providednomistakeshavebeenmade)willdisplay„iS“„Set“.Thedate/timemenucanbequittedatanytimebypressingtheOn/Offkey.
3.11.2AutostartUsingthe„Autostart“functiondoesnotreplacetemperingofthesampletotherequiredtemperaturebeforemeasurementisactivated.
If„Autostart“isactive,theunitwillwaitforpropertemperatureofthesample,indicatedbyadecreaseinpressure.Ittakesthispressureasthe„start“valueforthefollowingBODcalculations.However,themaximumwaitingtimeis3hours.Afterthistimetheunitwillautomaticallytakethecurrentpressureasthe„start“value,evenifnodecreaseinpressurehasbeendetected.Thiswillbeindicatedlaterbyflashingmeasurementvalues.
IfthetemperatureoftheBODsamplesissignificantlydifferentfromthespecifiedtemperature,achangeinpressurewillcauseerrorsindeterminingtheBODvalues.
The„Autostart“functioncanbeswitchedonandoff.Thesettingalwaysappliesfromthetimeitisdoneandappliestoalltheheadsontherack.
Confirm„Set“„Auto“withthe„ENTER“key.The„+“keyisusedtoswitchonthe„Autostart“function–“On“„Auto“andthe„-“keyisusedtoswitchitoff–„Off“„Auto“.Oncetheselectionhasbeenmade,thesub-menuisquittedwiththeOn/Offkey.
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3.11.3AutodurationConfirm„Set““dur“withthe„ENTER“key.The„+“and„-“keyscanbeusedtosetfiguresbetween1and28,aswellas„OFF“.Figuresbetween1and28specifythemeasurementperiodindays,while„OFF“deactivatesthe„Autoduration“.With„Autoduration“deactivated,theunitwillaskfortherequiredmeasurementperiodinthe„StartMode“foreachsampleand/orrackposition.Theunitispresetbythemanufacturerforan„Autoduration“of5–thatis,for5days‘BOD.The„Autoduration“settingisretainedevenifthepowersupplyfailsandvalidalwaysforallpositions.
3.11.4ChangingtheBatteriesTochangethebatterieswithoutaffectingacurrentmeasurement,makesureyouhavethetoolrequiredtoopenthebatterycompartmentandhavethreereplacementalkali-manganesebatteries(C/LR14)ready.Gototheparametersmenuandselectthebatterychangemenu„Set“„bAt“(„+“key).Pressthe„ENTER“key.Theunitwilldisplay„bAt“.Pressthe„ENTER“keyagain.Theunitdisplaywillnowflash,showing„bAt“„chg“.Waituntilthedisplaydisappears–thismaytakeupto6minutes.Whenameasurementisactive,thebatterychangemustbecarriedoutwithin4minutesandtheunitmustnotbeleftwithoutpowerformorethanoneminutemaximum!Ifnecessary,removeallsamplesfromtheframe,rotatetheframeandopenthebatterycompartment.Takeouttheoldbatteriesandreplacethemimmediatelywiththenewones,checkingforcorrectpolarity.Closethecoverofthebatterycompartment,replaceallthesamples(theirpositionsarenotimportant)andswitchtheunitonagain.Iftheunitswitchesautomaticallytothedate/timemenuafterachangeofbatteries,thismeansthatthebreakinthepowersupplywastoolong.Itwillthenbenecessarytoresetthedateandtime.
3.12DatatransferSwitchtheOxiDirectoff.ConnecttheOxiDirectRS232interfacewiththeserialinterfaceofthecomputerusingthecable,whichispartofthedelivery.TransferingstoreddatafromtheOxiDirecttothecomputerrequiresatransferprogram,e.g.Hyperterminal(thisispartofstandardWindowssoftware).Pleasefinddetailedinformationonourhomepageinthedownloadarea.PresstheREADkeyandholditdepressed.SwitchtheunitonwiththeOn/Offkey.Allow3decimalpointsinthelowerdisplaytoflashfor3seconds,thanreleasetheREADkey.Theunitisnowtransferringallstoreddata.
3.13Notes• Ifabottlehasbeenaddedtotherackwhileameasurementisactive,theunitmustbe
switchedonagain,sothatthisnewflaskisdetectedandcorrectmeasurementcantakeplace.
• Ifabottlehasbeenremovedpermanentlyfromtheframe,theunitshouldbeswitchedononceandthenoffagain,sothatthesemissingbottlenolongercauseapowerconsumption.
• Theunitwillswitchoffautomaticallyifnokeyispressedforapprox.45seconds.However,toachievemaximumbatterylife,theunitshouldalwaysbeswitchedoffimmediately,ifnofurtheruseractionisrequired.Theunitwillswitchinbackgroundmodewhenmeasurementsarerequired,indicatedbyalineinthetheupperdisplay.Oncemeasurementiscomplete,theunitswitchesoffagain.
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4. BODMeasurement
4.1 SampleVolume ThesamplevolumeisrelatedtotheexpectedBODvalue.TheOxiDirect®isdesigned
tooperatewiththefollowingrangesandsamplevolumes,allowingBODmeasurementupto0-4000mg/l,withoutanydilution.
Note
Theexpectedresultsshouldbeintheupperhalfoftherange.
FordomesticwasteitisgenerallyappropriatetoconsideraBOD5valuewhichisap-proximately80%oftheCODvalue.
RangeBODmg/l Samplevolumeinml DosageATH
0–40 428 10drops
0–80 360 10drops
0–200 244 5drops
0–400 157 5drops
0–800 94 3drops
0–2000 56 3drops
0–4000 21.7 1drops
4.2 PreparingtheWaterSample1. Check thepHvalueof theeffluentsample.TheoptimumpHvalue forbiochemical
oxidationisbetweenpH6.5and7.5.IfthepHvalueofthesampleishigherorlower,itshouldbepre-adjusted.AnysignificantdeviationwillresultinalowerBODvalue.IfthepHvalueistoohigh,itcanbereducedbyaddingdilutehydrochloricacid(1mol/l)ordilutesulphuricacid(1mol/l).IfthepHvalueislow,itcanbeadjustedwithasodiumhydroxidesolution(1mol/l).
2. Mixthewatersamplewellandallowtosettleforashortwhile.Itmayalsobeadvisabletofilterorhomogenisethesample.
3. Measurethesamplevolumeprecisely,usingtheappropriateoverflowmeasurementflaskandpourthesampleintothesamplebottle(itmaybehelpfultouseafunnelforthis).Ensurethatthesampleinthebottlecontainsarepresentativeportionofanysolidsinsuspension.Itisrecommendedthateachsampleshouldbetestedtwiceorthreetimes.
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4. To inhibit nitrification, we recommend the addition of nitrification inhibitor B(=AllylThiourea,orATH).Thisisparticularlyimportantforthelowrange0-40mg/l(forexample,whencheckingdischargesfromeffluenttreatmentplants).TherightamountofnitrificationinhibitorBisrelatedtothemeasurementrange-see4.1.
Note Nitrifyingbacteriaalsoconsumeoxygen.Thisconsumptioncanoccurwithinthefirst5
daysandismorelikelywithsampleswithlowBODlevels.Asageneralrule,theBODmeasurementshouldnotincludetheoxygenconsumptioncausedbynitrifyingbacteriaandthiscanbeinhibitedbyusingnitrificationinhibitorB.Thisinhibitorsuppressestheactivityofthebacteriabyenzymaticinhibition,sothatonlythebreakdownoforganicsubstancesinthesamplewillbemeasuredastheBODvalue.
If it isdesired tomeasureoxygenconsumption resulting fromnitrification (N-BOD),carryoutmeasurementssamples,onewithandonewithoutnitrificationinhibitorandcomparetheresults.ThedifferencebetweenthetwoBODvalueswillrepresenttheoxygendemandofthenitrifyingbacteria.
5. Addacleanmagneticstirringrodtoeachsamplebottleandadd3-4dropsof45%potassiumhydroxidesolutiontothesealgasket(thiswillabsorbthecarbondioxide).Theninsertthesealgasketintheneckofthebottle.
Important The samplemust never come into contactwith thepotassiumhydroxide solution.
Neverusegreaseoranyotherlubricantsasanadditionalsealingagent,fortheBODsensorsorforthesealgasket.Productsofthiskindmaycontainsolventswhichwillattack thesensor, resulting inseveredamage to theplastichousingandeven toafailureofthesensor.Theuseofsealinggreasesandlubricantsisnotcoveredbyourguarantee!
6. Beforemeasurementbegins, thepreparedsamplemustbebrought to thedesiredtemperature(e.g.BOD5,20°C).Thiscanbeachievedbyplacingthesampleinather-mostaticallycontrolledcabinet,whilestirringthesamplecontinuouslywiththeinductivestirringsystem.
TheOxiDirect®hasanoptional “Auto-Start” function,whichenables it tostartwithsamplesattemperaturesfrom15°to20°C.Whenthis“Auto-Start”functionisswit-chedon,thesystemchecksinspecificintervalswhethertherehasbeenadecreaseofthepressureintheBODbottleandwillnotstartthetimeruntilapressuredecreaseisdetected(latest,thetimerwillstart3hoursaftertheBODsensorhasbeenstarted).
7. PlacetheBODsensorsonthesamplebottlesandtightencarefully.Thisisextremelyimportant–thesystemmustbecompletelyair-tight.ThenplacetheBODbottle,withthesensorscrewedinposition,intothebottlerack.Thiscanbedoneinthethermo-staticallycontrolledcabinetitself.
Alternatively,becauseof theuser-friendlydesignof theOxiDirect®,youcanremovetheentireBODunit,withitsintegralbottlerack,fromthethermostaticallycontrolledcabinet,whileleavingtheinductivestirringsysteminthecabinet.Thereisnoneedtodisconnectthecabling.OncetheBODbottleshavebeenplacedintherack,thesystemispositionedovertheinductivestirringsystemsothatthe4adjustmentscrewsfitintheassociatedrecessesofthestirringsystem.
8. Startthemeasurementprocess(seeSection3.10).9. Incubatethesampleinaccordancewiththeinstruction(e.g.BOD5for5daysat20°C).
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5. InterpretingtheResults
Start 1. Day 2. Day 3. Day 4. Day 5. Day
300
250
200
150
100
50
0
1. TheBODvalueonanyparticulardaymustbehigherthantheoneofthepreviousday.
2. BODvaluesdonotincreaseinalinearmanner.Theincreaseisalwayssmallerthantheoneofthepreviousday.
3. IftheBODresultsincreaseinalinearmanner,thesamplehasahigherBODvaluethanexpected.
4. IfBODresultsincreasedsuddenlyduringthemeasurement,thismaybetheresultofnitrification.
5. IfBODresultsdecreasesuddenlyduringthemeasurement,thismayindicatesleakageofthesystem.
Theinformationgivenreferstonormalsamples(municipalwastes)andthenormalcir-cumstancesofaBODmeasurement.However,deviationarealwayspossible,dependingonthesamples.Forexample,ifthereisareadingofzeroafter5days,thismaybeasignofsevereinhibitionoroxidizingofthesample.
Inthecaseofindustrialeffluents,samplesmaycontaintoxicsubstances.Thesemustberemoved,orthesamplemustbediluted.Inaddition,nutrients(nitrogen;phosphate)andtraceelements(suchasiron)mustbepresentinsufficientconcentrations;otherwisebacterialgrowthmaybelimitedandartificiallylowBODvaluesmayberecorded.Whereproblemsofthiskindoccur,eachindividualcasemustbeconsidered.
Forfurtherinformation,pleaseaskforourapplicationreports.
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6. CheckingtheMeasurementSystem
TestSet(Ordercode:418328) ThetestsetenablesacheckofallthecomponentsoftheOxiDirect®.Usingaspecialreagenttablet,adefinedunderpressureisgeneratedinthesealedBODbottle.
7. Maintenance
High-qualitymetalalloysareusedforthecontactsbetweentheBODsensorsandthebottlerack.Ifnecessary,thecontactsmaybecleanedcarefullywithasoftcloth.
TocompensateforanyirregularitiesandtoensureoptimumcontactbetweentheBODsensorandthebottlerackaswellasinsuringproperstirring,theBODmeasurementsystemhas4levellingscrewsonitsbase.
Ifnecessary,theBODbaseunit(includingthebottlerack)andtheBODsensorscanbecleanedcarefullywithasoftcloth.
Allpartswhichcomeintocontactwiththesample(BODbottles;sealcups;magneticstirringrod)mustbecleanedthoroughlyaftereachmeasurement.Thebottlesmustbeemptiedcompletelyandwashedseveraltimesinhotwater.
Whenanycleaningagents,dish-washingliquids,etc.,areused,allpartsmustberinsedthoroughlyafterwards!TheresiduesofsuchagentscaninterferewithBODmeasure-ments.
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8. InductiveStirringSystem
Fig.1:Inductivestirringdrivewithstirringcontroller
➀ Stirringplace
➀ Stirringdevice
➀ Controller
➀ Plug
➀ Cable
➀
➀
➀
➀
➀
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8.1 Instructions
8.1.1 Correctuse
ThisinductivestirringsystemhasbeendesignedforstirringliquidsinBODbottles.
8.1.2 Symbols
Thefollowinginstructionsymbolsareusedinthisoperatingmanual:
DANGER! Thissignreferstodangerousvoltages
DANGER! Thissignreferstohazardoussituations. Riskstohumanlifeareindicatedbytheterm”LIFEHAZARD”
y CAUTION! Thissignindicatesriskstoequipmentandmachinery
i INFORMATION Thissignindicateseasierworkingpractices
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8.2 SafetyRequirements Foryourownsafety,youshouldobservethefollowingwarnings.
Thesafetywarningsindicateapossiblesourceofdanger.Atthesametimetheygiveinformationhowtoavoiddamage.Youwillalwaysfindthesesignswheredangercanoccur.
DANGER! Magnetism. Magneticormetallicparts(e.g.datacarriers,pacemakers,watches...)canbeaffectedbymagneticfields. Keepsuchpartsawayfromthemagneticstirrer(2)andthemagneticstirringrods
DANGER! Voltageandfrequencymustbewithintherangespecifiedforthecontrolunit(3)
y CAUTION! Donotuseinhazardouslocations
y CAUTION! Generalambientconditions: Stirringdrive(2):-10to+56°Cat100%humidity. Controlunit(3):0to+40°Catmax.80%humidity. Avoidextremetemperaturechanges. Thecontrolunit(3)mustnotbeusedinareasofhighhumidityorinareaswherewatermaysplash!
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y CAUTION! Donotplacehotsamplesontopofthemagneticstirrer(2). Maximumtemperature:56°C.
y CAUTION! Incaseofrepair,theequipmentmustonlybeopenedbyanauthorisedservicetechnician.Disconnectfrommainsbeforeopening!
y CAUTION! Donotallowthemagneticstirringrodtorestinanalternatingmagneticfield.Donotplacethemagneticstirringrodinastronginversemagneticfield.Thismayresultindestructionofthemagneticfieldofthestirringrod.
i INFORMATION Thelengthofthemagneticstirringrodmustnotexceed40mm. Donotuseellipticalstirringrodswitharoundcross-section.
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8.3 EquipmentDescriptionandFunction ThestirringsystemhasbeendesignedforstirringliquidsinstandardBODbottles.The
ultra-slimstirringdrive(2)has6stirringareas(1)andaseparatecontroller(3).Bottlescanberemovedfromtherackwithoutstoppingthestirringdrive(2).
The inductivestirringdrivehasnomotorand isthereforewear-free. It isparticularlydesignedforcontinuousstirringinaincubator.Itishermeticallysealed(fullyprotectedagainstsplashingwater)andcanbeusedevenintheroughestenvironments.Thewidespacebetweenthestirringareas(1)ensuresgoodventilationofthebottles,speciallyinanincubator.Thestirringdrive(2)isdrivenbyacontroller(3)withapre-setspeed.Whenturnedon,thesoftstartfeatureensuresauniformstartofthemagneticstirringrodsathalfspeed.
Every40seconds,thecontrollerreducesthestirringspeedby50%,re-centringthemagneticstirringrodinthemiddleofthebottle.
Themagneticstirringrodsaredrivensynchronously,preventingpracticallyanyinterfe-rencebetweenthem.
8.4 SetUp
DANGER!
Voltageandfrequencymustbewithintherangespecifiedforthecontrolunit(3)
DANGER! Magnetism.Magneticormetallicparts(e.g.datacarriers,pacemakers,watches...)canbeaffectedby
magneticfields.Keepsuchpartsawayfromthemagneticstirrer(2)andthemagneticstirringrods.
y CAUTION!
Donotuseinhazardouslocations
y CAUTION! Generalambientconditions: Stirringdrive(2):-10to+56°Cat100%humidity. Controlunit(3):0to+40°Catmax.80%humidity. Avoidextremetemperaturechanges. Thecontrolunit(3)mustnotbeusedinareasofhighhumidityorinareaswherewatermaysplash!
Thecontrolunit(3)doesnothaveanyswitch.Itisreadyforuseassoonasitispluggedin:Connectthecable(5)fromthestirringdrive(2)withthesocket(4)ofthecontrolunit(3)andfixit.Plugthecontrolunit(3)intothemainssocket.Toensureproperstirringthefourscrewsatthebottomoftherackcanbeusedtooptimizethedistancebetweenstirringdriveandmagneticstirringrod.
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8.5 Magneticstirringrods WerecommendtheuseofPTFE-coatedmagneticstirringrods.
i INFORMATION
Thelengthofthemagneticstirringrod(8)mustnotexceed40mm.
8.6 Stirring
y CAUTION! Donotplacehotsamplesonthemagneticstirrer(2). Maximumtemperature:56°C.
Fillthebottleswiththesample.
Placeamagneticstirringrodintoeverybottle.
PlacebottlesintheBODrack.
Thecontrolunit(3)ispresettooperateat320rpm.Every40secondsthespeedisreducedto200rpm,whichwillre-centerthenagneticstirringrod,ifnecessary.
Ifyouwanttostopthestirringprocess:
Disconnectthecontrolunit(3)fromthemainssocket.
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8.7 MaintenanceandCleaning Thestirringdrive(2)ismaintenance-free.
Themagneticdriveisembeddedinasyntheticresinandiscompletelywatertight.Cleanthesurfaceofthestirringdrive(2)inregularintervalsusingacleaningoradisinfectantsolutionsuitableforuseonPVC.Cleanthesurfaceofthestirringcontroller(3)usingdrycloth.
y CAUTION! Incaseofrepair,theequipmentmustonlybeopenedbyanauthorisedserviceagent.Disconnectfrommainsbefore
opening!
8.8 Troubleshooting
8.8.1 Themagneticstirringrodrotatesunevenly:
Overtime,someageingof thestirringrodcannotbeavoided.Thismayreduce itsmagnetisation.
y CAUTION! Donotallowthemagneticstirringrodtocometorestinanalternatingmagneticfield(e.g.inanunfilledstirringvesselwhenthestirringormixingmodeisselected).Donotsubjectthemagneticstirringrodtoastronginversemagneticfieldortostrongimpactshocks(e.g.bydroppingit).Thismayresultindestructionofthemagneticstirring
rod.Replaceitbyanewone.
8.8.2 Thestirringrodswervesbackandforth:
Swervingmovementsofthestirringrodmaybecausedbyirregularshapedbottomofthebottle.Replacethebottlebyanewone.
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9. TechnicalData
9.1 BODSystem
Type OxiDirect®
Measurementprinciple Manometric;mercury-free;electronicpressuresensor
Ranges 0-40,0-80,0-200,0-400,0-800,0-2000,0–4000mg/l[mg/lO2]
Applications BSB5,BSB7,OECD301F...
Resultdisplay BSB[mg/l];4-digits;7-segmentLED
Measurement BOD-range,volume,duration,displaytimeofmeasurementparameterdisplay
Measurementperiod User-selectable,between1and28days
Autoresultstorage upto28results,dependingonmeasurementperiod
Storageinterval –hourly(1day); (formeasurementperiodof...) –every2hours(2days); –daily(3-28days)
Automaticstartfunction –automaticstartafterpressuredecrease –canbeswitchedoff
Powersupply 3alkaline-manganesebatteries
Batterylife 1 year (normaluseasBOD5meter –max.one readingaday); Low-Batt-Indication
Clock Real-timeclock
Protectionclass IP54(sensorhead)
Dimensions 375x195x230mm (LxWxH) includingstirringunit
Housing ABS
Approval CE
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9.2 InductiveStirringSystem
Type InductiveStirringSystem
Stirringvolume 6BODbottles
Stirringpower 7W
Rotationspeed 320rpm (reducedto200rpmevery40s)
Dimensions(WxDxH) 270x180x25mm
Distancebetween 88mm stirringpoints
Weight(stirringdrive) 1800g
Housingmaterial PVC
GeneralAmbientConditions -10to+56°Cat100%humidity
Operatingvoltage 20Vmax.
Controlcable 2m
Protectionclass IP68(DIN40050)
Stirringcontroller 230Vversion 220–240V/10V/50-60Hz,protectionclassII, thermalfuse,CE 115Vversion 110–120V/10V/50-60Hz,protectionclassII, thermalfuse,CE Permanentambientconditions 0to+40°Catmax.80%humidity Protectionclass IP20(DIN40050)
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10. AccessoriesandSparePartsList
Article Ordercode
ReplacementBODsensor 2444430
Stirringcontroller 444413
Inductivestirringdrive 2444451
TestSet 418328
Potassiumhydroxidesolution(50ml) 2418634
NitrificationinhibitorB(50ml) 2418642
BODsamplebottle 418644
Sealcup(gasket) 418636
Magneticstirringrod 418637
Magneticstirringrodremover 418638
Overflowmeasuringflask,428ml 418660
Overflowmeasuringflask,360ml 418659
Overflowmeasuringflask,244ml 418658
Overflowmeasuringflask,157ml 418657
Overflowmeasuringflask,94ml 418656
Overflowmeasuringflask,56ml 418655
Overflowmeasuringflask,21.7ml 418664
Completesetoverflowflasks 418654
Thermostaticallycontrolledincubators seegeneralcatalogue
Thermostaticallycontrolledincubatorswithglassdoor seegeneralcatalogue
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Orbeco-Hellige Inc., 6456 Parkland Drive, Sarasota, Florida 34243Phone: 941-756-6410, Fax: [email protected], www.orbeco.com
Technical changes without notice
