Teledyne Slow Cooker 212R User Manual

INSTRUCTION MANUAL  
MODEL 212R  
THERMAL CONDUCTIVITY  
ANALYZER  
DANGER  
HIGHLYTOXICANDORFLAMMABLELIQUIDSORGASESMAYBEPRESENTINTHISMONITORINGSYSTEM.  
PERSONALPROTECTIVEEQUIPMENTMAYBEREQUIREDWHENSERVICINGTHISSYSTEM.  
HAZARDOUSVOLTAGESEXISTONCERTAINCOMPONENTSINTERNALLYWHICHMAYPERSISTFORA  
TIMEEVENAFTERTHEPOWERISTURNEDOFFANDDISCONNECTED.  
P/NM73212  
11/29/07  
ECO#07-0182  
ONLYAUTHORIZEDPERSONNELSHOULDCONDUCTMAINTENANCEAND/ORSERVICING. BEFORE  
CONDUCTINGANYMAINTENANCEORSERVICINGCONSULTWITHAUTHORIZEDSUPERVISOR/MANAGER.  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Table of Contents  
Model 212R  
1 Introduction  
1.1 Method of Analysis.......................................................5  
1.2 Sensitivity ....................................................................6  
1.3 Stability ........................................................................6  
1.4 Special Consideration .................................................6  
1.5 Physical Configuration.................................................6  
2 Installation  
2.1 Location .......................................................................7  
2.2 Electrical Requirements & Connections ......................7  
2.2.1 Primary Power ...............................................8  
2.2.2 Signal Output .................................................8  
2.2.3 Regulating Transformer..................................8  
2.2.4 Completion & Inspection................................9  
2.3 Gas Requirements & Connections...............................9  
2.3.1 Reference Gas...............................................10  
2.3.2 Zero Gas ........................................................10  
2.3.3 Span Gas.......................................................10  
2.3.4 Installation of Cylinder Supplies ....................11  
2.3.5 Sample Pressure ...........................................11  
2.3.6 Interconnecting Lines.....................................11  
2.3.7 Vent Lines ......................................................12  
3 Startup  
3.1 Preliminary...................................................................12  
3.2 Reference Gas Flow ....................................................13  
3.3 Zero Gas Flow .............................................................13  
3.4 Warmup........................................................................13  
3.5 Zero Standardization ...................................................13  
3.6 Span Standardization ..................................................14  
3.7 Bypass .........................................................................14  
3.8 Sample Mode...............................................................15  
4 Routine Operation  
4.1 Flowrate .......................................................................15  
4.2 Supporting Gas Supplies.............................................16  
3
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
4.3 Standardization............................................................16  
5 Periodic Maintenance  
5.1 Heater Fan ...................................................................17  
6 Troubleshooting  
6.1 Preliminary...................................................................17  
6.1.1 Electrical Checks ...........................................17  
6.1.2 Sampling System Checks..............................18  
6.1.3 Summary of Preliminary Checks....................18  
6.2 Loss of Zero Control.....................................................18  
6.2.1 Dynamic Balance Procedure .........................19  
6.3 Correct Operation.........................................................20  
6.4 Incorrect Operation.......................................................21  
6.4.1 Analyzer Leak Check.....................................21  
6.4.2 Temperature Control Check ...........................22  
7 Calibration Data  
7.1 Ranges ........................................................................24  
7.2 Output Signal ...............................................................25  
7.3 Span Setting ................................................................25  
7.4 Recommended Accessory Gases................................25  
7.4.1 Reference Gas...............................................25  
7.4.2 Zero Gas ........................................................25  
7.4.3 Span Gas.......................................................26  
Appendix  
A
Recommended 2-Year Spare Parts List .......................26  
A
Drawing List .................................................................27  
A Specifications...................................................................... 28  
Teledyne Analytical Instruments  
4
 
Thermal Conductivity Analyzer  
Model 212R  
1.  
INTRODUCTION  
1.1  
Method of Analysis.  
The Model 212R compares the thermal conductivity of a sample gas to  
that of a fixed composition reference gas and produces an electrical output  
signal that is calibrated to represent the difference between the two gases.  
Due to the nonspecific nature of thermal conductivity measurement,  
standard gases of known composition will be required to calibrate the ana-  
lyzer. The accuracy of the analysis will be dependent on the accuracy to  
which the composition of the standard gases is known.  
The measuring unit is a four element hot wire cell that forms one-half of  
an alternating current bridge circuit. Two of the hot wire elements are ex-  
posed to the sample gas, and two to the reference gas. The other half of the  
bridge circuit is formed by the center tapped secondary winding of a trans-  
former.  
With reference and zero standardization gas flowing, the bridge circuit  
is balanced at one end of the measurement range. A span standardization gas  
containing a known concentration of the component of interest is then  
introduced into the sample path, and the resulting error signal generated by  
the now unbalanced bridge circuit is calibrated to represent the span gas  
mixture. The concentration of the component of interest in the span gas is  
predicated by the specified ranges of the analysis. After the instrument has  
been standardized the electrical error signal is directly related to the compo-  
nent of interest content of the sample gas.  
The magnitude of the measuring bridge error signal is much too small to  
drive an indicating or recording instrument. A 100:1 step-up transformer,  
followed by an electronic amplifier stage, is utilized to amplify the error  
signal to an acceptable amplitude for demodulation. The signal is then  
conditionedappropriatelytodriverecordingequipment.  
5
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
1.2  
Sensitivity.  
Differencesinthermalconductivitythatproduceameasuringbridgeerror  
signalof 0.25microvoltswillbesensedbytheanalyzer.  
1.3  
Stability.  
Internalvariables,otherthanthesamplegas,thatcouldproducevariations  
intheoutputsignalarecarefullycontrolledbytheModel212R. Zerodriftis  
approximately2%ofthefinerangeina24hourperiodofoperation;further-  
more,thedriftisbidirectionalwithaproperlyinstalledanalyzerandisrelatedto  
grosschangesinambienttemperature. Thevariables,bothinternalandexternal,  
thatcanaffectthestabilityoftheanalyzerwillbedealtwithindetailintheinstal-  
lationandtroubleshootingsectionsofthismanual.  
1.4  
Special Consideration.  
ConsiderationofUsingthe212RtoMeasureH2,ormeasureothercompounds  
in H2. H2 in the gas state can be assume of one tow states, para H2, or ortho  
H2. EachhasitsownThermalConductivityValue. Thesedifferbyabout10%  
fromoneanother.  
Sothismustbetakenintoconsiderationwhenattemptingtousethe212RonH2  
streams.  
WewouldrecommendoneconsultWikipedia.comorothersourcestolearn  
moreaboutthesetwostatesofH2andhowthethermalconductivityofthegas  
streamvarieswiththestate.  
IfforinstanceoneisusingpureH2asareferencegas,andthisgasisinthepara  
stateassociatedwithcryogenicH2recentlyvaporized,andthisisthencompared  
tocylinderH2whichmaybeinadifferentstate,thenconsiderablemeasurement  
errorscanresult.  
ContactTeledyneforfurtherguidanceorinformationonyourspecificapplica-  
tion.  
1.5  
Physical Configuration.  
Theanalyzerishousedinasheetsteelcasethatisdesignedtoflushmount  
withinanequipmentpanel. Electricalcontrols,aswellasanintegralgascontrol  
Teledyne Analytical Instruments  
6
 
Thermal Conductivity Analyzer  
Model 212R  
panel,arelocatedimmediatelybehindahingedfrontaccessdoor.Theanalyzer  
issuitableforinstallationinashelterednon-hazardousarea.  
Arecordingand/orindicatingdevicewillberequiredtotransducethe  
electricaloutputsignalintoreadableinformation.  
2.  
INSTALLATION  
2.1  
Location.  
Theanalyzershouldbepanelmountedinanuprightpositioninanarea that  
is notexposedtothefollowingconditions:  
1. Directsunlight.  
2. Drafts of air.  
3. Shock and vibration.  
4. Temperatures other than that one would expect to see in  
airconditioned, temperature controlled office of lab enviroment.  
The 212Rshouldnotbemountedoutdoorsorsubjecttemperature fluc-  
tuationsbeyond2or3degrees.  
Theanalyzershouldbeplacedascloseaspossible,subjecttotheafore-  
mentionedconditions,tothesamplepoint.  
Outlinediagramsofbothunitswillbefoundinthedrawingsection.After  
thecutouthasbeenmadeintheequipmentpanel TAIrecommendsthatthe  
analyzerbeusedasatemplatetolayoutthefourmountingholes.Suchaproce-  
durewillcompensateforsheetmetaltoleranceerrors.  
2.2  
Electrical Requirements and Connections.  
Provisionshavebeenmadetoaccommodatethethreeexternalcircuit  
connectionsrequiredbytheanalyzer. Accessholesononesideoftheanalyzer  
case(seeOutlineDiagram)areprovidedfortheinstallationoftheconduitand  
electricalwiring. Allthreecustomerconnectedcircuitsaretobeterminatedon  
thebarrierterminalstripidentifiedTS1”.  
Toinstalltheconduitandwiring,theinnerhorizontallyhingedpanelmustbe  
opened (to open the panel, turn the fastener screw at the top of the Panel a 1/4  
turnccw).Whileinstallingtheconduitandwiringbecarefulnottodisturbthe  
foaminsulationliningtheinteriorofthecaseanymorethanisabsolutelyneces-  
sary.  
7
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
IMPORTANT: The foam lining the interior of the analyzer is an  
integral part of the environmental temperature  
control system. Removal or destruction of this  
lining will result in erratic instrument perfor-  
mance.  
2.2.1 Primary Power.  
Asourceofsinglephase,105to125volt,60cyclepowerwillberequired  
tooperatetheanalyzer. Themaximumpowerconsumptionoftheanalyzeris  
500watts.  
NOTE: The analyzer is also available for 50 cycle operation  
with special modifications and accessories.  
RefertotheInterconnectionDiagraminthedrawingsectionofthemanual  
andconnectthepowerandgroundwiringasshown. Besuretopolarizethe  
powerserviceconnectionsasindicated. Whenconnectingthewires,donot  
leaveanexcessiveamountofslackwithintheanalyzer. Twovacuumtubesare  
locatedjustbelowthewiringareaandthewiringshouldbeinstalledtobewell  
clearofthem.  
2.2.2 Signal Output.  
Connectatwoconductorshieldedcablebetweentheanalyzerandrecord-  
ingequipment. Besuretoobservetheproperpolarityatbothinstruments.  
Connecttheshieldofthecableontheindicatedterminalattheanalyzeronly,and  
cutbackandinsulatetheshieldattherecorder.  
NOTE: Connecting the shield at both ends of a cable when  
dealing with low level circuits can create a ground  
loop between two instruments. Improperly installed  
shielding can produce more noise in a low level circuit  
than no shielding at all.  
2.2.3 Regulating Transformer.  
Teledyne Analytical Instruments  
8
 
Thermal Conductivity Analyzer  
Model 212R  
Runthecableattachedtothetransformerunitinthroughtheaccesshole  
that is equipped with the cable clamp and terminate it as specified on the  
interconnectiondiagram.  
2.2.4. Completion and Inspection.  
After the electrical connections have been completed, slide any excess  
slack back into the conduits so that the installed wiring is not in contact with  
the components mounted on the analyzer chassis.  
Removethethreefoamstripsthataretapedtotheinsideoftheanalyzer  
doorandusethemtostufftheconduitopenings. Itisimportantthatthese  
openings be as well sealed as possible.  
Checktoseethatthetemperaturecontrolprintedcircuitboard,andall  
vacuumtubesarefirmlyseatedintheirrespectivesockets.  
Closeandlatchthecontrolpanel. Thereshouldbenofurtherneedtohave  
accesstotheinterioroftheanalyzer. Allcontrolsandadjustmentsarearranged  
sothattheycanbemanipulatedwithoutdisturbingthedelicatetemperature  
equilibriumoftheinstrumentinterior.  
2.3  
Gas Requirements and Connections.  
Beforeattemptinginstallationofthesampleandsupportinggaslinesand  
accessoriesgivecarefulconsiderationtothefollowingimportantinstallation  
notes.  
Note #1: Itisabsolutelynecessarythatallconnectionsandcomponents  
inthegascontrolsystemaheadofthemeasuringcellbeleak  
free. TowardthatendTAIhastestedtheintegralsampling  
systemunderpressurewithasensitiveleakdetectorand  
certifiesthattheanalyzerisleakfree.  
Note #2: Usenosolderconnectionsinthesystem. Solderingfluxes  
outgas into the sample lines and produce erratic output  
readings. Acid type soldering fluxes actually attack and  
permanently change the characteristics of the detector cell  
measuringelements.  
Note #3: All sample system tubing should be new and clean. Many  
gases and vapors are absorbed by dirt or oxide coatings on  
tubing walls. These gases and vapors are released as the  
ambient temperature rises. Because of the high sensitivity of  
the analyzer, this absorption-desorption phenomenon can  
9
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
causealargefluctuationinoutputsignal.Forbestresults,use  
electropolished SS tubing  
Note #4: Becauseofthediffusionofairthroughcompositionmaterials,  
only dual stage SS regulators with metallic diaphragms should  
be used in conjunction with the sample and supporting gas  
supplies.  
Note #5: Regulatorsmustbethoroughlypurged(burped)priortouse.  
2.3.1 Reference Gas.  
Acylinderofgasoffixedcompositionisrequiredasthereferencefor  
comparisonwiththesamplegas. Atotallackofimpuritiesinthereference  
would be ideal but is not necessary. An impurity concentration of up to 50%  
ofthenarrowestrangeofinterestistolerable. Theexactcompositionofthe  
referencegasisacademicaslongastheuseriscertainthatitfallswithinthelimits  
specifiedinSection7ofthemanual. Theimportantconsiderationisthatthe  
compositionofthereferencegasremainunchangedwheninuse.  
NOTE: When it becomes necessary to replace the reference  
gas, the analyzer will have to be recalibrated.  
2.3.2 Zero Gas.  
A supply of gas, composed of the background gas of the analysis and  
the lowest attainable concentration of impurity, will be required to standard-  
ize one end of the ranges of interest. The composition of the zero gas must  
be known to the same exactitude expected of the analysis. TAI suggests that  
the gas be obtained from a supplier that will certify its composition. Recom-  
mendations as to the composition of the gas will be found in Section 7 of the  
manual.  
2.3.3 Span Gas.  
A supply of gas, composed of the background of the analysis plus a  
known concentration of the component of interest, will be required to stan-  
dardize the sensitivity of the analyzer. Again, the composition of the gas  
must be known to the same order of accuracy expected of the analyzer.  
Analysis and certification of the composition is desirable. Specific recom-  
mendations governing the composition of the span gas will be found in  
Section 7 of the manual.  
Teledyne Analytical Instruments  
10  
 
Thermal Conductivity Analyzer  
Model 212R  
2.3.4 Installation of Cylinder Supplies.  
Thereferenceandstandardgascylindersshouldbeinstalledasclosetothe  
analyzeraspossible. Eachcylindershouldbeprovidedwithadualstage,  
metallicdiaphragm,pressurereducingregulator. Wheninstallingtheregulators,  
crackthecylindervalveopensothatgasisflowing. Thisprocedurewillprevent  
airfrombeingentrappedintheregulator,andeliminateacommonsourceof  
supportinggascontamination. Improperinstallationofacylinderregulatorcan  
appreciablychangethecompositionofastandardgas.Airtrappedintheregula-  
torwilldiffusebackintothecylinder,andtheimpurityconcentrationofthe  
compositionwillbealtered. Whendealingwiththezerogas,thealterationofthe  
compositioncanbesignificant.  
Onceinstalled,priortouse,theregulatorsforreference,spanandzero  
gasesmustbepurgedbyalterativelypressuringthefirststage,withthesecond  
stageoff,thenbleedingoutthefirststagebyopeningthesecondstage,backand  
forth severaltimes.  
Note: Make sure to close the cylinder prior to bleeding the first stage  
through the second.  
2.3.5 Sample Pressure.  
Thesamplepointshouldbeequippedwithametallicdiaphragmpressure  
regulatorandthepressurereducedtobetween10and50psig. Theregulator  
shouldbeinstalledasclosetothesamplepointaspossibletominimizesample  
linelagtime.  
2.3.6 Interconnecting Lines.  
Theinletandventconnectionsareidentifiedontheanalyzeroutlinedia-  
gram. Theconnectionsarestainlesssteel1/8"femalepipecouplingsthatare  
braisedintoagasconnectorbarmountedwithintheanalyzer. Thebraisedpipe  
couplingwasselectedasatransitionsothatthetorquegeneratedduringinstalla-  
tionoftheexternalsystemwouldbeisolatedfromtheinternalsystem. Bulkhead  
typefittingscanbeaccidentlytwisted,andleakspromotedinhardtoreachareas  
withintheanalyzer. TAIsuggeststhat1/4"tubingandadapterfittingsbeused  
throughouttheexternalsamplingandsupportinggassystem.  
11  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
2.3.7 Vent Lines.  
Thesamplepath,referencepath,andanintegralbypasssystemventfrom  
separateportsattherearoftheanalyzer. Whereverpossible,TAIrecommends  
thatthegasesbepermittedtoventdirectlytotheatmosphere.Ifitisnecessary  
tocarrythesegasestoaremoteareathefollowingprecautionsmustbeob-  
servedwheninstallingtheventlines:  
1) Theventlinesmustbe1/4"tubingorlargersothatnobackpressure  
resultingfromrestrictedflowisexperiencedbythemeasuringcell.  
2) Thesampleandreferencepathsmustventintoanareathatexperi-  
ences the same ambient pressure conditions.  
3) Theambientpressureattheventlocationshouldundergonomore  
thannormalbarometricpressurefluctuations.  
4) Theventlinesmustbeinstalledsothatwateranddustcannotaccu-  
mulate in them.  
Apressuredifferentialexistingatthecellbetweenthereferenceandsample  
willresultinacorrespondingchangeinoutputsignal. Thereferenceandsample  
pathflowmetersarelocatedupstreamfrom thecellsothatbothcellpathscan  
ventdirectlytoatmosphere. Therandombounceofthefloatsintheflowmeters,  
whenlocateddownstreamfromthemeasuringcell,canproduceupto5%noise  
ontheoutputsignal.  
3.0  
3.1  
STARTUP  
Preliminary.  
The following preliminary steps should be accomplished before apply-  
ing power or starting gas flow.  
1. Check the integral gas control panel and be sure that all valves are  
closed (fully cw). Do not jam the sample, reference, and bypass  
meteringvalves.  
2. Place the “RANGE” switch on the #2 position.  
3. Set the “SPAN” control to the reading recorded in Section 7 of the  
manual.  
Teledyne Analytical Instruments  
12  
 
Thermal Conductivity Analyzer  
Model 212R  
4.Determinewhatthesamplepressureisandsettheoutputpressureof  
the cylinder gas supplies to agree with the sample pressure. This  
procedure, although not absolutely necessary, will minimize flow  
adjustments when the sample path is switched to the various inputs.  
5. Turn the analyzer and recorder power switches to “ON”.  
3.2 Reference Gas Flow.  
Openthereferencegasthrottlevalveadjacenttothe “Ref.Flowmeter,  
andsetthevalveforanindicatedflowrateofbetween0.1and0.3scfh. Since  
theactualsettingisnotcritical,TAIsuggeststhattheflowbesetat0.1scfhto  
conservethereferencegassupply.  
3.3  
Zero Gas Flow.  
OpentheZEROvalve(ccwuntilareleaseintensionisfelt),andadjust  
thethrottlevalvetotherightoftheSAMPLEFLOWflowmeterforanindi-  
catedflowrateof0.3scfh.  
3.4  
Warmup.  
Awarm-upperiodoftwenty-four(24)hoursisrecommendedtostabilize  
theinterioroftheanalyzeratthecontroltemperaturelevel. Untilthemeasuring  
celltemperaturehasequilibratedwiththecontroltemperature,theoutputsignal  
willdrift.  
Duringthewarmupperiod,checktherecorderperiodically. Asthedrift  
rate decreases, increase the sensitivity by moving the range switch towards  
Range #1.  
IMPORTANT:  
ThezerocontrolwillhavelittleornoeffectuntilRange#1isreached.Ifthe  
recorderisoffscaletowardselectricalzero(negativesignal)after24hoursof  
runningonzerogas,usetheprocedureoutlinedinSection6.2. Thedriftratewill  
decreaseexponentially. Whentherateofchangeslowstoapproximately1%  
perhour,placetheRANGEswitchonposition#1andreadjusttheZERO”  
controlsothattherecorderisreadingmidscale. Donotattempttocalibratethe  
analyzeruntiltherecorderindicationstabilizes.  
3.5  
Zero Standardization.  
13  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
Aftertheanalyzerstabilizesadjustthe"ZERO"controluntiltherecorder  
indicatestheimpurityconcentrationofthezerogascomposition. Besurethat  
therangeswitchisonposition#1andthatthesamplepathflowrateis0.3scfh.  
NOTE if the"ZERO" or "FINE ZERO" pot runs out of adjustment and  
the analyzer can not be calibrated, set this pot back to mid-scale. Then use  
the "COURSE ZERO" pot to readjust the zero calibration as close as pos-  
sible to zero calibration. And last use the "ZERO" ot "FINE ZERO" pot to  
fine adjust the zero calibration.  
3.6  
Span Standardization.  
Afterthezerohasbeenstandardized,switchtheselectorvalveto"Span",  
andresetthesamplepathflowrateto0.3scfh. Therecordershouldcometo  
balanceon,orcloseto, thecompositionofthespangas.  
Theanalyzerisfactorycalibratedtomakesurethattheoutputislinearover  
allthreerangesofinterest. Calibrationisachievedwithmixingblocktechnique  
andthespansettingrecordedinSection7isderivedatthattime.  
Iftheanalyzerperformedasdescribedinthewarm-upprocedure(Section  
3.4),andfailstocloselyapproximatethecompositionofthespangas,thereis  
groundsfordoubtingthespangasmixture. Becauseofthedifficultyinvolvedin  
obtainingpreciseanalysisofsmallamountsofimpuritiesincylindergas,and  
becauseoftheeasewithwhichthegascanbecontaminatedsubsequentto  
analysis,anylargeerrorinresponsetothespangasshouldbesuspect. Insucha  
caseTAIrecommendsthattheanalyzerbeoperatedattherecommendedspan  
settinguntilthespangasisreanalyzed.  
Ifadjustmentofthespancontrolisnecessarytocompensateforminor  
discrepanciesbetweentherecordedsettingandthespangasreading,TAI  
suggeststhatthezeroandspan proceduresberepeateduntilnofurtheradjust-  
mentisrequired.  
3.7  
Bypass.  
Theintegralgascontrolpanelfeaturesabypassflowmeterandthrottle  
valve that is located downstream from the input manifold (see the analyzer  
piping schematic in the drawing section). The bypass system can be used to  
speed the response of the analyzer to changes in the process. The bypass  
flowmeter will indicate flowrates that are a factor of ten greater than the  
sample path flowmeter. TAI recommends that the bypass system be used  
whenever the sample path is switched and particularly after using the span  
gas. The time required for the analyzer to stabilize on an impurity concentra-  
tion within the limits of Range #1, after having been exposed to a concentra-  
tion within the limits of Range #3, is not a function of cell response which is  
Teledyne Analytical Instruments  
14  
 
Thermal Conductivity Analyzer  
Model 212R  
virtuallyinstantaneous. Recoveryisafunctionofhowlongittakestopurgethe  
samplingsystemupstreamfromthecell.Acceleratingthesamplepathflowrate  
willspeedtheresponse.  
NOTE:  
TAI recommends that some bypass flow be permitted  
at all times. The bypass throttle meter is a part of the  
input manifold. Being so located means that the  
throttle valve lies between the sample side of the cell  
and atmosphere.  
Without some bypass flow it is possible that atmo-  
sphere could diffuse into the sample line. Do not  
attempt to use the throttle valve as a shut off valve.  
Jamming the valve will damage the metering needle.  
3.8Sample Mode.  
Aftertheanalyzerhasbeenstandardized,switchtheselectorvalveto  
"Sample". Set the bypass flow so that the float is visibly elevated from the  
bottom of the tube and then readjust the sample flowrate to 0.3 scfh. No  
furtheradjustmentsarerequired.  
NOTE: Although the bellows type valves used in the input  
manifold are among the best available, TAI suggests  
that the span gas be turned OFF at the cylinder when  
not in use, and the span line relieved of pressure  
before closing the analyzer span valve. Such a proce-  
dure will eliminate any possibility of the span gas  
diffusing into the sample path of the analyzer. Nor-  
mally, the recommended span gas composition con-  
tains a component of interest content of 3/4 the coars-  
est range of analysis. The component of interest  
content of the sample gas, on the other hand, is usu-  
ally well within the finest range of analysis. Instrument  
sensitivity in Range #1 is 100 times greater than in  
Range #3. The user can readily see what even a  
minute rate of span gas diffusion would do to the  
validity of a Range #1 analysis.  
4.  
ROUTINE OPERATION  
Flowrates.  
4.1  
15  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
Thereferenceandsampleflowratesshouldbecheckeddaily. Theinstru-  
mentissomewhatflowsensitive. OperatingonRange#1achangeinflowrateof  
0.1scfhwillcauseacorrespondingchangeinsensitivityoffrom1to20%of  
scale. Onthecoarserranges,thechangeinsensitivitywouldbeundetectable.  
Thesamplepathflowrateshouldbemaintainedat0.3scfh,thereference  
pathflowrateat0.1scfh,andthebypassflowmeterfloatshouldbeslightlyabove  
thebottomoftheindicatorglass.  
4.2 Supporting Gas Supplies.  
Supportingcylindergassuppliesshouldbecheckedfrequentlyonaroutine  
basiswithparticularattentionfocusedonthereferencegas. Asparecylinderof  
referencegasshouldbeavailableatalltimes. Whenthecylinderpressuredrops  
below100psigthereferencesupplyshouldbereplacedastheoperationofthe  
regulatorisquestionableatpressuresbelowthispoint.  
Whenreplacingsupplycylinders,besuretobleedthegasthroughthe  
cylinder valve while installing the pressure regulator (see Section 2.3.4). It is  
also advisable to check the connections with soap water whenever a supply  
cylinder is changed.  
4.3  
Standardization.  
Theanalyzermustbecompletelyrestandardizedwheneverthereference  
gassupplyisreplaced. Barringunforeseendifficultieswiththeanalyzer,re-  
standardizationshouldnotbenecessarybetweenreferencecylinderreplacement  
periodsiftheanalyzerisruncontinuously. Iftheanalyzerisshutdownforlong  
periodoftimeusethestartupprocedure(initsentirety)whenoperationistobe  
resumed.  
NOTE: TAI strongly recommends that the analyzer run con-  
tinuously with gas flowing in both the sample and  
reference paths. During inactive periods arrange the  
input manifold so that zero gas is flowing. Gas sup-  
plies can be conserved by reducing the sample and  
reference path flowrates to less than 0.1 scfh and  
closing off the bypass flow completely.  
Teledyne Analytical Instruments  
16  
 
Thermal Conductivity Analyzer  
Model 212R  
Duetothedelicatebalanceofthethermalconductivitycellemployedinthe  
analyzer,exposuretotheatmosphereinanuncontrolledtemperatureenviron-  
mentisundesirable. Afterextendedshutdownperiodsmanydaysofoperation  
mayberequiredfortheanalyzertore-stabilize.  
5.  
PERIODIC MAINTENANCE  
Heater Fan.  
5.1  
Theheaterfanistheonlycomponentwithintheanalyzerthatrequires  
periodic attention. Whenever the reference gas is replaced the motor bear-  
ings will require a few drops of light machine oil. Since oiling the fan motor  
necessitatesopeningtheinnerdooroftheanalyzer,theinstrumentwillrequirethe  
necessarytemperatureequilibratingtimeafterthedoorisclosed. Withzerogas  
flowingbesurethattheanalyzerhasstabilizedontheRange#1positionbefore  
re-standardizationisattempted.  
6.  
TROUBLE SHOOTING  
6.1  
Preliminary.  
Iftheanalyzerissuspectedofincorrectoperation,asapreliminaryto  
evaluation, always arrange the input manifold so that zero gas is flowing  
through the sample path of the analyzer. Never attempt to evaluate the  
performance of the instrument with sample gas flowing.  
Analysisbythermalconductivityisnonspecificinnature. Athermalcon-  
ductivityanalyzerwiththefinerangesensitivityoftheModel212Rwill respond  
tomanyinfluencingfactorsotherthanthecomponentofinterest;particularly  
whenoperatedatRange#1sensitivity.  
It is necessary, therefore, to eliminate as many external variables as  
possible if the performance of the analyzer is to be assessed. Programming  
the analyzer for zero gas places both paths of the measuring cell on relatively  
reliablecylindergassources.  
6.1.1  
Electrical Checks.  
17  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
Checktoseethatboththeanalyzerandrecorderarebeingfurnished  
electrical power. Check to see that the analyzer and recorder fuses are intact.  
Check all electrical connections outside of the analyzer.  
6.1.2 Sampling System Checks.  
Besurethatthereisanadequatesupplyofreferencegasandthatthe  
sample and reference path flowrates are correct. Check to see that there are  
no obstructions in the vent paths from the analyzer. Check all external  
plumbing connections for leaks with soap water.  
6.1.3 Summary of Preliminary Checks.  
Theanalyzerinnerdoorshouldnotbeopenedandnoadjustments,beyond  
manipulationofthenormallyusedcontrols,shouldbemadeuntilalltheafore-  
mentionedpreliminarieshavebeencompletedandanynecessaryremedial  
repairseffected.  
6.2  
Loss of Zero Control.  
IflossofzerocontrolonRange#1isexperiencedduringinitialstartupor  
afterthereferencegassupplyhasbeenchanged,thedynamicbalanceprocedure  
mustberepeated.  
Lossofzerocontrol,undersuchcircumstances,indicatesthattheimpurity  
concentrationwithinthereferencegasisdifferentthanthatofthegasusedduring  
factorycheckout(orthepreviouscylinder)anddoesnotinitselfindicatea  
defectiveanalyzer.  
Theanalyzerwasadjustedatthefactorytohaveazerobalanceatcloseto  
themidpointofthezerocontrolpotentiometer(dualdialreadingof500)witha  
commonsourceofhighpuritycylindergassupplyingboththesampleand  
referencepathsofthecell. Iftherecorderisoffscaleandcannotbereturned  
withthezerocontrol,thedynamicbalanceproceduremustbeemployedto  
restorecontrolbeforefurtherconclusionsastoinstrumentperformancecanbe  
made.  
Teledyne Analytical Instruments  
18  
 
Thermal Conductivity Analyzer  
Model 212R  
6.2.1  
Dynamic Balance Procedure.  
Themeasuringbridgecircuit(seeschematic)incorporatestwo 10 turn  
potentiometersthatareutilizedtocompensateforminutedifferencesinthe  
resistive and reactive properties of the hot wire elements and the center  
tapped secondary of the bridge transformer in the reference and zero gas  
relatedtotheapplication.  
Thepotentiometersareofthescrewdriveradjustmenttypeandare  
equippedwithshaftlockingassembliesthathavebeenfactoryadjustedtocreate  
enoughfrictionsothattheshaftwillnotchangepositioninshipment.Thepotenti-  
ometersarelocatedontheamplifierchassis,andarecontrolledthroughtwo  
holesidentifiedRESISTIVEandREACTIVEontheinnercontrolpanel.  
DO NOT OPEN THE INNER PANEL OF THE ANALYZER TO  
GAIN ACCESS TO THESE CONTROLS. The balance adjustments  
should not be disturbed if the analyzer is not up to operating temperature.  
Correct bridge balance can only be achieved at operating temperature be-  
cause of the inherent thermal junctions within the potentiometers themselves.  
The minute voltages produced by contact between the dissimilar materials  
within the potentiometers are effectively balanced out in the procedure when  
it is accomplished at operating temperature. Because the voltage generated  
by these junctions varies with temperature, and because the analyzer will  
resolve a 0.25 microvolt change in bridge voltage, temperature stability is a  
mandatory prerequisite to the dynamic balance procedure.  
To restore zero control within the limits of Range # 1, employ the  
followingProcedure:  
1) Withzerogasflowing,adjustthesampleandreferencegasflowme-  
terstothesamevaluebetween0.1and0.3scfh.  
2) Set the ZERO potentiometer to 500.  
3) Connectavoltmetertotheinstrumentsignaloutput. Connectan  
oscilloscope to the probe point an d set the sweep rate to 5  
milliseconds. Set the voltage level so ± 15 volts can be read.  
4) If a reading of +15 or –15 volts is indicated on the oscilloscope  
with the RANGE switch set to Range # 1 the instrument is  
significantly unbalanced. Set to Range #2 and proceed to step 4).  
If the voltage is lower in magnitude than + or – 15 skip down to  
step 6).  
19  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
5) Usingascrewdriverthathasashaftdiameterof1/8andashaft  
length of at least 6”, turn the “Reactive” balance adjustment all  
the way counterclockwise (CCW) until the potentiometer stop  
pointisreached. Turntheadjustmentbackclockwise(CW)5full  
turnstocentertheadjustment.  
6) TurntheResistivebalanceadjustmentallthewayclockwise(CW)  
untilthepotentiometerstoppointisreached.  
7) Slowly turn the “Resistive” adjustment until the output reaches its  
lowest value. If the reading is negative adjust to the most nega-  
tivevaluepossible.  
8) TurntheReactivebalanceadjustmentslowlyCWandCCWto  
obtain the lowest possible output value. Again, if the reading is  
negative adjust to the most negative value possible.  
9) Repeat steps 6) and 7) until the output value is as low as these  
adjustments can make it.  
10) DetunetheinstrumentbyturningtheResistivebalanceadjust  
ment ½ turn CW. This will bring the signal out of the baseline  
noise, which could otherwise cause non-linear response at the  
low concentration end.  
NOTE: Due to minute differences between measuring cells  
and the electronics in the bridge circuit found in vari-  
ous instruments, some analyzers will have to be bal-  
anced at a point higher than 10% of scale while others  
can be balanced even closer to electrical zero. The  
10% of scale recommended in step 6 of the procedure  
is an arbitrary starting point. If the bridge circuit can  
be easily balanced at this signal level, the procedure  
should be repeated at a point even closer to electrical  
zero. Conversely, if balance cannot be accomplished  
at 10% of scale, the operator will have to select a  
higher recorder set point for the procedure. In any  
case, the object is to accomplish dynamic balance  
with the lowest magnitude of analyzer cutout signal  
attainable with the analyzer at Range #1 sensitivity.  
6.3  
Correct Operation.  
If a stable recording is achieved when the analyzer is operated on zero  
gas, erratic performance must be attributed to the customers sampling system  
Teledyne Analytical Instruments  
20  
 
Thermal Conductivity Analyzer  
Model 212R  
orincorrectinstrumentinstallation. Thefollowingconditionscanproducean  
erratic output from the analyzer:  
1) Installationinanareathatissubjecttolargechangesinambient  
temperature, direct sunlight, drafts from wind, blowers, or air condi-  
tioners. Any of the foregoing conditions will produce a bidirectional  
(diurnal)variationinoutputsignal.  
2) Sample gas with a moisture content of 10 ppm or greater. Again, the  
outputwillvarybi-directionalitywithambienttemperaturechanges.  
Ifthesamplegasisknowntohaveafairlyhighmoisturecontenta  
dryershouldbeinstalledinthesampleline.  
3) Eventhesmallestleakanywhereinthesamplingsystemupstream  
from the analyzer, a small leak at a fitting, valve, or regulator, will  
cause almost constant variation in analyzer output. The resulting  
signaldriftwouldbeerraticandcouldbeeitherbi-directionalor  
unidirectional.  
4) Acidinthesamplingsystem(solderingfluxes)willproducecontinu-  
ous, uncontrollable, unidirectional output signal drift. Sample tubing  
that has been treated with descaling chemicals, if subject to above  
ambient temperatures, will outgas continuously. Any form of acid in  
the sampling system will outgas at high temperatures and attack the  
hot wire elements of the cell.  
5) Composition materials (diaphragms, tubing, etc.) in the sampling  
system will produce erratic, unpredictable changes in output signal  
level because of their permeability to gases other than the sample.  
The nylon tubing normally used in quick disconnect type sampling  
systems will produce diurnal output signal excursions in the order of  
10 to 20% of the fine range of analysis.  
6.4  
IncorrectOperation.  
Iftheanalyzerisnotstableonzerogas,andthesupportinggasinstallation  
hasbeenmadeandcheckedinaccordancewithsections2and3,thefollowing  
proceduresshouldbeemployed.  
6.4.1 Analyzer Leak  
21  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
Checkaspreviouslystated,theanalyzersentiresamplingsystemhasbeen  
checkedunderpressurewithaleakdetector. However,iftheexternalsystem  
checksoutandtheinstrumentisdisplayingalargediurnaloruni-directionaldrift,  
theinteriorsamplingsystemshouldbecheckedforleaks.Donotopenthe  
analyzerinnerdoor. Usethefollowingprocedure:  
1)  
2)  
Acquireasourceofcylinderheliumandthroughadualstage  
regulator connect it to a length of 1/8" tubing.  
Open the outer door of the analyzer and insert the tubing be-  
tween the edge of the sample control panel and the outer case.  
CAUTION: Do not insert the tubing along the edges of the  
larger swing-down control panel as there is danger of  
obstructing the fan or short circuiting the electronics.  
The end of the tubing should be shaped into a curve  
so that the foam lining is not overly disturbed and the  
tubing should only be inserted a couple of inches into  
theinterior.  
3)  
Start the helium flowing. Keep the flowrate low so as not to  
disturbthetemperatureequilibriumoftheanalyzerinterior.  
4)  
Observe the recorder. If any leaks are present in the interior  
sampling system, the recorder will be driven off scale in one  
direction or the other. NOTE: The analyzer should be on Range  
#1 and the zero control adjusted so that the recorder is reading  
mid-scale. The direction the recorder indication moves is a  
function of the type of zero and reference gas being used (which  
varies per application) and which path of the sampling system  
(sample or reference) the leak is located in. If the recorder  
responds to an atmosphere of helium within the analyzer, all  
connections inside the analyzer must be checked.  
6.4.2 Temperature Control Check.  
Theinteriortemperatureoftheanalyzerisregulatedtoaconstantvalueto  
within.002degreescentigrade. Theactualtemperaturecontrolpointvaries  
slightlyperapplicationandisafunctionofthecomponentsusedinthepropor-  
tionaltemperaturecontrolcircuit.  
Iftherecorderisdisplayingalargediurnalrecordingthatisrelatedtothe  
timeofdayintermsofthedifferentialbetweendayandnightambienttempera-  
ture,troubleinthetemperaturecontrolcircuitryisindicated. Again,thissymp-  
Teledyne Analytical Instruments  
22  
 
Thermal Conductivity Analyzer  
Model 212R  
tommustbeevidentwithzerogasflowing. Ifthissymptomisdisplayedonly  
whenthesampleisflowing,theproblemisrelatedtoone(ormore)ofthefive  
(5)pointsoutlinedinsection7.3.  
Tocheckthetemperaturecontrolcircuit,usethefollowingprocedures:  
1)  
WiththepowerswitchON,openthecontrolpaneldoorand  
check to see if the fan is running. If it is not, check the left hand  
fuse. This fuse protects the entire temperature control circuit  
(see schematic). If the fuse will not hold, a short circuit is  
indicated. Disconnecttheprintedcircuitcardandreplacethe  
fuse. If the fuse holds (as indicated by the fan running) the  
printed circuit card will have to be replaced.  
NOTE:Unlesscompetentelectronictechniciansareavailable,TAI  
recommendsthatareplacementprintedcircuitcardbeordered  
and the existing board returned to the factory for repair. Repair  
charges (out of warrantee) will be based on time and material.  
A schematic of the proportional temperature control card is  
included among the drawings at the rear of the manual.  
2)  
Ifthefusewillnotholdwiththeboardremoved,a short isindi  
cated in the fan, the heater resistors, or the interconnecting  
wiring. Withtheboardremoved,checkwiringandcomponents  
for short circuits.  
3)  
Ifthefanisrunning,connectanACvoltmeteracrossanyoneof  
the heater resistors on the fan assembly (the meter should be set  
to read 50 VAC). In a properly operating circuit, the meter  
should read approximately 47 volts (heater control full on) as the  
control panel is open and the thermistor should be demanding  
maximum heater voltage. If no voltage is present, either the  
circuit card or the thermistor probe is faulty. Isolate the problem  
byfirstdisconnectingthecircuitboardfromitssocketandwith  
anohmmetercheckbetweenterminals5and6ofterminalstrip  
TS2. Ifareadingisobtained(disregardactualresistance)the  
thermistorisintactandanewcircuitcardwillbenecessary. If  
no reading is obtained, a new probe assembly will be required.  
4)  
Ifapproximately47VACismeasuredacrosstheheaterresis-  
tors, a runaway, or correct, circuit is indicated. To determine  
which is the case, hold a soldering iron in close proximity (1/2")  
totheendofthethermistorprobeandobservethemeter.  
23  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
CAUTION: Do not touch the thermistor probe with the iron. The  
end of the probe is tied and taped to the sample tubing  
below the cell cover. If the meter reading suddenly  
drops to zero, remove the soldering iron immediately.  
After the area around the thermistor cools, the voltage  
across the heater resistors should again climb to 47  
volts. Such action indicates a properly functioning  
heater circuit. If the meter stays in the 47 volt region,  
the circuit card will have to be replaced.  
7.0 CALIBRATION DATA FOR MODEL 212R  
SERIAL NUMBER: 195929  
7.1  
Ranges.  
Therangesoftheanalyzerare:  
RangeSwitchPosition#1:  
Range Switch Position #2:  
0-50,000 ppm N2 in H2  
0-5000 ppm N2 in H2  
Range Switch Position #3:  
0-500 ppm N2 in H2  
Teledyne Analytical Instruments  
24  
 
Thermal Conductivity Analyzer  
Model 212R  
7.2  
Output Signal:  
Outputcoincideswith100%analysis.  
4mA  
=
=
=
=
0 ppm N2 in H2  
20mA  
50,000 ppm N2 in H2 - Range #1  
5000 ppm  
500 ppm  
N2 in H2 - Range #2  
N2 in H2 - Range #3  
7.3  
7.4  
Span Setting: 555  
Recommended Accessory Gases.  
H2 Purity  
H2 Purity  
ZeroGas  
99.999  
Reference Gas  
SpanGas  
99.999  
350-450 ppm N2 in H2  
7.4.1 Reference Gas.  
Withaequivalentimpurityoflessthan3%ofrange1. Theimpurityratio  
mustremainconstant.Whenthereferencegassupplyisreplaced,theanalyzer  
mustbere-standardized.  
7.4.2 Zero Gas.  
Becauseofthedifficultiesinvolvedinobtainingagasinpureform,thezero  
gasmustbepurchasedfromasupplierwhowillcertifythecylinderastoits  
content. Theequivalentimpurityconcentrationofthegasmustbelessthan3%  
ofrange1. Whenthezerogasisintroducedforstandardization,therange  
switchmustbeinRange1,andthezerocontrolsetsuchthattherecorder  
indicatesthezerogasimpurity.  
IMPORTANT:Atstartup, besurethatthespancontroldialissettothe  
numberrecordedinSection7.3.  
25  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
7.4.3 Span Gas.  
Containinganequivalentimpurity. Again,thespangasmustbeprocured  
fromasupplierwhowillcertifyitscomposition. Therangeswitchmustbein  
range3whenthespangasisintroduced.  
IMPORTANT: Theaccuracyoftheanalysisisdirectlyrelatedtothe  
usersknowledgeofthespangascomposition.  
ReferenceandSampleFlowrates 0.3SCFH  
Bypass Flowrate 3.0 SCFH  
NOTE:  
Cylinder and sample stream pressure settings must  
be adjusted in order to maintain the above flowrates  
when switching from one sample to another.  
RECOMMENDED SPARE PARTS LIST  
QUANTITY PART NO.  
DESCRIPTION  
1
1
1
1
A-6251  
A-6981  
F-45  
MeasuringCellBlockAssembly  
ProportionalTemperatureControl  
SampleFlowmeterTube  
F-22  
SampleFlowmeterBypassTube  
Aminimumchargeappliestoallsparepartorders.  
IMPORTANT: Ordersforreplacementpartsshouldincludethepart  
number,themodelandserialnumberoftheanalyzerinwhichtheyaretobe  
used.  
Teledyne Analytical Instruments  
26  
 
Thermal Conductivity Analyzer  
Model 212R  
Ordersshouldbesentto:  
TELEDYNE Analytical Instruments  
16830ChestnutStreet  
City of Industry, CA 91749-1580  
Phone (626) 934-1500, Fax (626) 961-2538  
TWX (910) 584-1887 TDYANYL COID  
Web:  
Drawing List  
B-73356  
D-73212  
A-72035  
C-73085  
C-73088  
Outline Diagram  
Final Assembly  
Piping Diagram  
Main PCB Schematic  
Power Supply PCB Schematic  
Replacement Parts Order Information  
A minimum charge of $150.00 is application to all spare parts  
orders.  
Important:Ordersforreplacementpartsshouldincludetheart  
number(ifavailable)andthemodelandserialnumberoftheinstrument  
forwhichthepartisintended.  
TeledyneAnalyticalInstruments  
16830Chestnutstreet  
CityofIndustry,Ca91748-1580  
Telephone:(626)961-2538  
(626) 934-1500  
Fax:  
(626) 961-2538  
(626) 934-1651  
27  
Teledyne Analytical Instruments  
 
Thermal Conductivity Analyzer  
Model 212R  
APPENDIX  
Specifications:  
Ranges: Three decade ranges: Minimum Full scale(ppm)  
20ppmHydrogenbalanceArgon  
25 ppm Hydrogen balance Nitrogen, Air  
100ppm NitrogenbalanceArgon,Helium  
100ppmHeliumbalanceAir  
150ppmNitrogen,CarbonMonoxidebalanceHydrogen  
200ppmOxygenbalanceArgon  
Range ID:  
3 range ID contacts  
Local Range ID LED’S  
Detector: Thermal conductivity sensor  
Signal Output: 0-1VDC negative ground  
4-20maDC Isolated ground  
Accuracy:  
±2%fullscaleformost binarymixture  
atconstanttemperature.±5%ofFull  
Scaleoveroperatingtemperature(once  
temperatureequilibriumhasbeen achieved)  
Operating  
Temperature:  
20 – 30°C (68° F to 85° F)  
Sample  
Requirement:  
Sample:0.3SCFH  
Reference:0.1SCFH  
Display:  
Mounting:  
DigitalLEDreadout(3½Digit)  
Flushpanelmount.  
Response Time:  
90%offullscalelessthen60seconds.  
Formostapplication.  
Stability:  
Lessthen2%fullscaledriftover24  
hours  
Power  
requirement:  
110VAC,50/60Hz (220VACoptional)  
Teledyne Analytical Instruments  
28  
 

Taylor Scale 3840BL User Manual
Tech Craft TV Video Accessories TS50W User Manual
Tote Vision Computer Monitor LCD 2300HD User Manual
Tripp Lite Battery Charger APSX1012SW User Manual
Turbo Air Freezer TGF 23F User Manual
Uniden Cordless Telephone DX8200 User Manual
Vantec Fan SF9225L User Manual
Vermont Casting Indoor Fireplace DVRT36 User Manual
Viking Gas Grill VGBQ300 User Manual
Watlow Electric Thermostat SERIES146 User Manual