training module 2 temperature m

8/17/2019 Training Module 2 Temperature m

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Instrumentation

Temperature


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2

100°C100°C 0°C0°C

T jct. Tref.a

b

Metal a b Hot junction or measuring junction Cold junction or reference junction

Ni-Cr

Ni-Al

Thermocouples

Introduction

It is the German physicist SEEBECK (1770 - 1!1" #ho disco$ered

in 121% the thermo-electric e&&ect

It noted that% in a closed circuit% made up o& t#o di&&erent metal #ire%

'oined at their ends% there #as irth o& an electric current i& they #ere

carried t#o end o& this circuit at di&&erent temperatures


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!

Thermocouples (cont)"

Correspondence and thermocouple choice

T#o metals constitutin* the thermocouples are selected accordin* to

temperature to e measured

In a thermocouple% the &irst metal named is al#ays the positi$e one


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+

Thermocouple Type Names of Materials Useful Range

BPlatinum30% Rhodium (+) 2500 -3100F

Platinum 6% Rhodium (-) 1370-1700C

CW5Re Tungten 5% Rhenium (+) 3000-!200F

W26Re Tungten 26% Rhenium

(-) 1650-2315C

ECh"omel (+) 200-1650F

Contantan (-) #5-#00C

J$"on (+) 200-1!00F

Contantan (-) #5-760C

KCh"omel (+) 200-2300F

lumel (-) #5-1260C

N

&i'"oil (+) 1200-2300F

&iil (-) 650-1260C

R Platinum 13% Rhodium (+) 1600-26!0F

Platinum (-) 70-1!50C

SPlatinum 10% Rhodium (+) 100-26!0F

Platinum (-) #0-1!50C

TCoe" (+) -330-660F

Contantan (-) -200-350C

Thermocouples Types ( ,uality $s Cost "


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Cold #eldin* and compensation #ire

The thermocouple is composed o& 2 metal #ire o& di&&erent nature

.ne o& the ends is #elded% it is the 'unction or the hot #eldin*) The

other end% the 'unction o& re&erence or cold #eldin*% is connected to

the measurin* circuit

/ di&&erence in temperature et#een the hot #eldin* and the cold#eldin* causes one potential di&&erence (electromoti$e orce"

&unction o& the $ariation in temperature) Temperature o& the point o&

measurement is then deduced startin* &rom no#led*e &rom

temperature o& the 'unction o& re&erence

It #ill thus e necessary to otain a temperature cold #eldin* as

constant as possile so to carry out only one correction


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To otain this result% #e use cales o& compensation #hich mo$e the#eldin* cold o& the proe head to their end and #e use a corrector

unit or cold #eldin* to otain the true $alue

The / and B #ires o& the thermocouple constitute the sensor) The

connection et#een the 'unction intermediary T2 and the 'unction o&

re&erence Tre&) is ensured y the cales o& compensation /3 and B3

respecti$ely associate #ith metals / and B)


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Class and precision

The thermocouples &ollo# the standard CEI + #hich de&ines the

allo#ed tolerances) There are se$eral types o& thermocouples &or

$arious ran*es o& temperature% sensiti$ities and characteristics)

The thermocouple 4 is used &or its hi*h sensiti$ity ut there is a

possile iron contamination in o5idi6in* atmosphere startin* &rom+00C% #e #ill a$oid to use it)

The thermocouple T has stron* sensiti$ity and is used &or the

temperature measurement ne*ati$e)

The thermocouple 8 or K has an e5cellent thermoelectric staility%

and no prolem o& o5idation at hi*h temperature (ran*e use&ul &rom 0

to 1000C"

The thermocouple 9 : S are used &or the hi*h temperatures


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/ccuracy Classes)


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t100

Introduction

The principle o& measurement o& these sensors is the resistance

$ariation o& the metal conductor accordin* to the temperature

The platinum has a *ood linearity% precision% staility #ith the

ad$anta*e to e t#ist in $ery &ine #ire) This is #hy% the sensor #ith

platinum resistance% indicated y >t% is *enerally used in industrialen$ironment

The #ire used is $ery &ine so #e #ill tae care to use an anti-

$iratory system to a$oid its dama*e)


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>t100 (cont)"

8orm and standard

International standard CEI 71% deri$ed &rom ?I8 standard +!)70

de&ines the $alues nominal as #ell as the acceptale $ariations

The >t 100 start #ith a resistance o& 100 ohms at 0 C (&rom #here

the >t100 term") =ith 100C the resistance is o& 1!)1 .hms

The standard de&ines t#o classes@ Tolerance Classi&ies /A (0)1 0)002 TD" o& - 200C #ith 00C

@ Tolerance Classi&ies BA (0)!0 0)00 TD" o& - 200C #ith 0C

The class / *i$es a precision appro5imately 2 times etter than the

B) In *eneral% the class B is &or industrial use and the class / is &or

laoratories)

The ran*e o& use in our installationA -0 +00C


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>t100 (cont)"


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T#o =ire 9T? connection

sin* the 2-#ire method% the t#o #ires that pro$ide the 9T? #ith its

e5citation current and the t#o #ires across #hich the 9T? $olta*e ismeasured are the same) There is inaccuracy in usin* this method

that i& the lead resistance in the #ires is hi*h% the $olta*e measured

F.% is si*ni&icantly hi*her than the $olta*e that is present across the

9T? itsel&)

@ Simple : Cheap)

@ Inaccurate

@ or short distance

et#een sensor : T5)


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IE9H1

9H2

9H!9TF.

Three =ire 9T? connection

sin* the !-#ire method% there are 2 parallel #ires connected to one

end o& the $ariale resistance% Fo is tain* the $olta*e drop across

one o& the #ires only % not oth)

@


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our =ire 9T? connection

The +-#ire method has the ad$anta*e o& not ein* a&&ected y the

lead resistances ecause they are on a hi*h impedance path *oin*throu*h the de$ice that is per&ormin* the $olta*e measurement

there&ore% you *et a much more accurate measurement o& the

$olta*e across the 9T?)

@ Fery E5pensi$e)

@ Completely /ccurate)

@ or lon* distances

et#een sensor : T5)


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>t100 (cont)"

8orm and standard

/s coe&&) Temp is not constant % hence there is also tale &or >T100)


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.ptical pyrometers

Introduction

The optical pyrometer is a method o& measurement o& the

temperature ased on the relation et#een the temperature o& a

ody and the optical radiation (in&ra-red or $isile" that it ody emits)

Het us tae &or e5ample% an electrical resistance% &eed y a po#er

source) It is started lac% ut it starts to emit heat% it is the in$isile

thermal radiation called in&ra-red) Then resistance ecomes red andemits a $isile radiation

The interest o& the optical pyrometer is to allo# the determination o& a

temperature #ithout contact #ith the o'ectA it is thus an adapted

method #hen the conditions installations do not allo# the use a

traditional thermometric sensors

@ Fery hi*h temperature (J 1200C"

@ art mo$in*

@ Hocali6ation o& the hot spots)


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1;

Pyrometer* o" "adiation the"momete"* i a non-'onta't int"ument that dete't ano,e't u".a'e teme"atu"e / meau"ing the teme"atu"e o. theele't"omagneti' "adiation (in."a"ed o" iile) emitted ."om the o,e't

P/"omete" a"e eentiall/ hoto dete'to" hi'h a"e 'aale o. ao"ing ene"g/* o"meau"ing the 4 ae intenit/* at a a"ti'ula" aelength o" ithin a 'e"tain "ange o.aelength

Typical Broadand Pyrometer

http://www.efunda.com/DesignStandards/sensors/pyrometers/pyrometers_theory.cfmhttp://www.efunda.com/DesignStandards/sensors/pyrometers/pyrometers_theory.cfm


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The Electromagnetic Radiation Spectrum

Courtesy o& the /d$anced Hi*ht Source% Bereley Ha

(Ernest .rlando Ha#rence Bereley 8ational Haoratory"

http://www-als.lbl.gov/als/http://www.lbl.gov/http://www.lbl.gov/http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.htmlhttp://www.lbl.gov/http://www-als.lbl.gov/als/


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21

Instruments &or Scanner

1) Kiln I9 Scanner)

2) Kiln position Encoder)

!) Kiln rotation sensor ( >ulse S#itch")

+) Tire yrometers &or Tires)


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22


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2!

9esolution &or T Scanner

@ Scannin* &reuency L 20 re$Msec@ Kiln diameter L meters@ Kiln speed L ! re$M min hence 1 re$ L 1)7metres in 20 sec@ Scanner measures 20 lines in one sec)@ Nence the scanner trace +00 lines in the #hole circum&erence o& iln

@ Scanner can read line o& 170M(20 O 20" D L !);2 cms@ ?ata &or one scan is coded in 12 it oMp &or !0 de*)@ .F L 120 % hence #e use 1M! o& the +0;units)@


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2+

.F and Kiln Geometry

9euested data A@ .F an*le

@ T#o >ass points in terms o& an*les and len*th &rom iln re&erence@ Girth Gear place &rom Kiln re&erence)@ Tires place &rom iln re&erence)@ Kiln ?iameter @ Kiln Hen*th


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2

Kiln >ulse Sensor

Inducti$e pro5imity s#itch M


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2

Hi$e Scan cycle ( 9a# Scan "


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Scanner Inter&ace pro*ram

@ P /5is Fie# % Temperature #ise ( >ea %


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2

Internal temperature% used to de&ine the internal iln temperature pro&ile)

The internal temperature pro&ile is used

&or calculatin* the ric M coatin* thicness) /s many temperature points

can e added as needed) The position o& the &irst and last temperature

point cannot e modi&ied) =hen ad'ustin* the position and temperature

&or a temperature point% the current ric and coatin* thicness are sho#n

to the ri*ht)


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9e&ractory >ro*ram

Nistorical ?ase &or Kiln riin*

training module 2 temperature m

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