Thermocouple ntsuas yuam kev thiab ceev faj

Paub meej: Thermocouples yog ib qho yooj yim tshaj plaws thiab feem ntau cov ntsuas kub. Txawm li cas los xij, yog tias tsis ua tib zoo saib thaum siv, nws tuaj yeem ua rau kev ntsuas loj dua. Xav txog cov teeb meem uas twb muaj lawm, cov ntsiab lus tseem ceeb cuam tshuam rau kev ntsuas qhov yuam kev suav nrog cov thermocouple ntxig qhov tob, lub sijhawm teb, thermal hluav taws xob, thiab thermal impedance, nrog rau cov xov hlau tsis sib xws, cov dej tsis sib xws hauv armored thermocouples, xaiv oxidation ntawm K-hom thermocouples, K-xeev. , kev khiav hauj lwm huab cua, rwb thaiv tsev tsis kam, thiab degradation ntawm thermocouples. Yuav tsum ceev faj thaum siv. Txhawm rau txhim kho kev ntsuas qhov tseeb thiab txuas ntxiv lub neej kev pab cuam ntawm thermocouples, nws yog qhov zoo rau qee qhov.
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Hauv cov txheej txheem ntsuas kub uas twb muaj lawm, feem ntau siv ntsuas kub ntsuas - thermocouple, vim nws cov qauv yooj yim, feem ntau yuam kev rau "thermocouple nrog ob lub xov hlau txuas nrog lub txee", tab sis qhov tseeb, nws tsis yog. Txawm hais tias tus qauv ntawm thermocouples yog qhov yooj yim, tseem muaj ntau yam teeb meem uas yuav tshwm sim thaum siv. Piv txwv li, kev teeb tsa tsis raug lossis kev siv tsis raug tuaj yeem ua rau muaj kev ntsuas ntau dua, thiab txawm tias qhov kev ntsuas thermocouple tsim nyog yuav yog vim kev ua haujlwm tsis raug thiab tsis ua haujlwm, xws li carburization hauv qhov chaw txo qis. Yog tias tsis ua tiag tiag, K-hom thermocouples kuj tseem tuaj yeem ua siab ntev vim xaiv oxidation.
Txhawm rau txhim kho kev ntsuas qhov tseeb, txo qhov ntsuas qhov yuam kev, thiab txuas ntxiv lub neej kev pabcuam ntawm cov thermocouples, cov neeg siv yuav tsum tsis yog tsuas yog muaj kev txawj ua haujlwm, tab sis kuj paub txog physics, chemistry, thiab cov ntaub ntawv. Raws li kev xyaum ua ntau xyoo thiab cov ncauj lus kom ntxaws ntxiv rau cov ntaub ntawv tseem ceeb, kev ntsuas qhov yuam kev ntawm cov thermocouples thiab lawv cov kev tiv thaiv.
2. Heterogeneity nyhuv ntawm thermocouple xov hlau
(1) Cov khoom siv thermocouple nws tus kheej tsis sib xws
Thermocouples raug kuaj hauv chav ntsuas, thiab raws li cov cai, qhov tob ntawm kev nkag mus rau hauv qhov cub ntsuas tsuas yog 300 hli. Yog li ntawd, qhov kev ntsuam xyuas ntawm txhua lub thermocouple tsuas tuaj yeem cuam tshuam lossis cuam tshuam tus cwj pwm pib los ntawm kev ntsuas ntawm 300mm ntev thermocouple hlau. Txawm li cas los xij, thaum qhov ntev ntawm cov thermocouple ntev, feem ntau ntawm ob lub xov hlau yog nyob rau hauv qhov chaw kub. Yog hais tias lub thermocouple hlau tsis sib xws, raws li txoj cai lub voj voog tsis sib xws, qhov ntsuas tau yog ywj siab ntawm qhov ntev. Txawm li cas los xij, cov xov hlau tsis sib xws, tshwj xeeb tshaj yog cov hlau tsis tshua muaj hluav taws xob, tuaj yeem tsim cov hluav taws xob hluav taws xob hauv zos nyob rau hauv qhov kub thiab txias, hu ua parasitic electromotive rog. Qhov yuam kev tshwm sim los ntawm qhov muaj peev xwm parasitic hu ua heterogeneity error.
Nyob rau hauv cov kev pab cuam uas twb muaj lawm validation rau precious hlau thiab tsis tshua muaj alloy thermocouples, lub heterogeneity ntawm thermocouples tseem tsis tau muab, thiab tsuas yog nyob rau hauv lub thermocouple hlau qauv ua thermocouple xov hlau muaj ib co kev cai tsis sib xws. Xam cov thermal electromotive quab yuam siv lub taub hau mus rau tus Tsov tus tw xeem txoj kev. Cov pa thermocouple hlau ntau lawm cov nroj tsuag tsim tsis sib xws thermoelectric electromotive quab yuam raws li lub teb chaws tus qauv kom tau raws li cov khoom yuav tsum tau.
(2) Thermocouple xov hlau yog ua los ntawm cov khoom sib txawv
Rau cov thermocouples ntawm cov txheej txheem tshiab, txawm tias qhov tsis sib xws ntawm thermal EMF tuaj yeem ua tau raws li qhov yuav tsum tau ua, kev rov ua dua tuaj yeem ua rau muaj kev cuam tshuam ntawm cov txheej txheem khoov thermocouples, uas yuav plam uniformity. Tsis tas li ntawd, vim yog siv cov xov tooj ntev ntev ntawm cov xov tooj ntawm qhov kub siab, xws li cov thermocouples tso rau hauv cov khoom siv hluav taws xob, lawv yuav degrade lossis txawm xaim raws li cov kev taw qhia ntawm cov hlau ntev. Raws li qhov kub thiab txias, qhov degradation yuav nce. Thaum cov khoom tivthaiv nyob rau hauv qhov chaw uas qhov kub thiab txias gradient txo, Nws tuaj yeem tsim hluav taws xob quab yuam superimposed ntawm tag nrho cov thermal EMF vim qhov kev ntsuas kab mob tsis raug.

3. Shunt yuam kev ntawm armored thermocouples
(1) Kev hloov pauv yuam kev
Huaju Group lub qhov cub carburizing uas nruab nrog armored thermocouples tsuas yog tso cai rau ib lub lis piam. Txhawm rau tshawb xyuas cov laj thawj, tus kws sau ntawv tau mus rau qhov chaw kuaj xyuas thiab pom tsis muaj qhov txawv txav, yog li lawv yuav tsum tau xeem cov txiaj ntsig ntawm chav ntsuas thiab pom tias lawv tsim nyog. Yog li qhov teeb meem yog dab tsi? Thaum kawg, raws li cov yam ntxwv ntawm qhov chaw ntawm cov thermocouples ntsia, nws tau pom tias qhov teeb meem tshwm sim los ntawm qhov tsis raug ntawm kev sib txawv ntawm armored thermocouples.
Qhov hu ua shunt yuam kev yog ntsuas siv armored thermocouples. Thaum qhov kub ntawm qhov nruab nrab ntawm lub thermocouple siab tshaj 800 ° C, vim qhov txo qis hauv rwb thaiv tsev, lub thermocouple qhia qhov tshwm sim txawv txav, uas yog hu ua shunt yuam kev. Raws li lub hauv paus ntsiab lus ntawm uniform circuit, qhov ntsuas kub ntawm thermocouple tsuas yog cuam tshuam nrog qhov ntsuas kub ntawm ob qhov kawg ntawm qhov ntsuas thiab siv qhov kawg, thiab tsis muaj kev ywj pheej ntawm qhov kub thiab txias hauv nruab nrab. Txawm li cas los xij, vim qhov tseeb tias cov rwb thaiv tsev ntawm armored thermocouples yog MgO hmoov, qhov kub thiab txias nce los ntawm 100 ° C, thiab cov rwb thaiv tsev kuj txo qis los ntawm qhov kev txiav txim ntawm qhov loj. Thaum qhov nruab nrab ntawm qhov kub thiab txias, yuav tsum muaj qhov xau tam sim no, uas ua rau muaj kev cuam tshuam ntawm cov khoom siv hluav taws xob ntawm lub thermocouple.
(2) Kev hloov pauv yuam kev
Armored thermocouple muab tso rau hauv lub cub tawg, specifications thiab sim tej yam kev mob: txoj kab uas hla ф 4.8mm, 25m ntev, nrog ib tug central cua sov cheeb tsam ntev ntawm 20m thiab ib tug kub ntawm 1000 degree. Hauv qhov kev sim no, qhov kub sib txawv ntawm qhov ntsuas qhov ntsuas kub thiab qhov nruab nrab yog 200 degree. Yog tias qhov ntsuas kub ntawm qhov ntsuas kawg siab tshaj qhov nruab nrab, qhov tsis zoo yuav tshwm sim; Ntawm qhov tsis sib xws, qhov yuam kev zoo yog tsim. Yog hais tias qhov kub ntawm qhov sib txawv ntawm ob yog 200 ° C, qhov kev hloov pauv yuam kev yog li 100 ° C. Qhov no tsis tuaj yeem tsis quav ntsej, xws li cov xwm txheej xws li shunt yuam kev thiab hom thiab txoj kab uas hla ntawm armored thermocouples [2]
Qhov cuam tshuam cuam tshuam thiab tiv thaiv kev hloov pauv yuam kev
Nws yog ib qho tsim nyog yuav tsum nkag siab txog qhov cuam tshuam ntawm kev hloov pauv tsis raug thiab siv cov kev ntsuas tsim nyog los txo lossis tshem tawm qhov cuam tshuam ntawm kev hloov pauv yuam kev. Cov txiaj ntsig tau qhia tias qhov yuam kev shunt ntawm armored thermocouples yog tshwm sim los ntawm qhov kub thiab txias.
(1) Armored thermocouple txoj kab uas hla
Rau K-hom armored thermocouples nrog qhov ntev ntawm 9m (MgO rwb thaiv tsev), tsuas yog qhov nruab nrab ntawm cov thermocouple yog cua sov. Cov txiaj ntsig ntawm kev sim qhia tau hais tias qhov loj ntawm qhov kev hloov pauv qhov yuam kev yog qhov sib npaug ntawm lub hauv paus square ntawm nws txoj kab uas hla (txoj kab uas hla me me dhau los ua raws li txoj cai), uas txhais tau hais tias qhov me me ntawm txoj kab uas hla, qhov ntau dua qhov kev hloov pauv yuam kev.
Thaum qhov nruab nrab kub siab tshaj 800 degree, ф 3.2mm armored thermocouples yuav ua rau shunt yuam kev. Txawm li cas los xij, ф 6.4mm thiab ф Thaum nruab nrab kub ntawm 8mm armored thermocouple yog 900 degree, qhov yuam kev shunt tseem tsis tau pom. hais txog ф 6.4mm (hotline txoj kab uas hla ntawm Φ 1.4mm) thiab ф 8mm (cov cua kub hlau txoj kab uas hla yog ф A 2.0mm armored thermocouple generates ib txoj kab uas hla thaum kub nyob rau hauv nruab nrab ib feem yog 1100 degree φ 8mm armored thermocouple. Ib nrab ntawm 6.4 hli. Tus nqi (50%) yog nyob ze ntawm lub square ntawm cov hlau txoj kab uas hla ntawm ob armored thermocouples (1.42/2.02), raws li zoo raws li lub square ratio ntawm lub electrode hlau txoj kab uas hla, uas yog tus kuj ratio ntawm cov hlau electrode. . Yog li ntawd, txhawm rau txhawm rau txo qhov yuam kev, yuav tsum xaiv txoj kab uas hla ntawm armored thermocouple.

(2) Qhov ntsuas kub ntawm qhov nruab nrab
Yog tias qhov kub ntawm qhov nruab nrab siab tshaj 800 degree, tej zaum yuav muaj kev hloov pauv yuam kev, thiab nws qhov loj yuav nce exponentially nrog qhov kub thiab txias. Yog li ntawd, tshwj tsis yog rau qhov ntsuas qhov kawg, lwm qhov yuav tsum tau zam saum 800 degree ntau li ntau tau.
1) Qhov ntev thiab txoj hauj lwm ntawm cov cua sov cheeb tsam nyob rau hauv nruab nrab seem
Thaum qhov kub ntawm qhov nruab nrab ntawm qhov cua sov yog siab tshaj 800 degree, qhov ntev ntawm qhov cua sov cheeb tsam thiab qhov deb ntawm qhov ntsuas qhov kawg, qhov ntau dua qhov kev hloov pauv yuam kev. Yog li ntawd, qhov ntev ntawm cov cua sov sawb yuav tsum luv li sai tau thiab yuav tsum tsis txhob muab cua sov los ntawm kev ntsuas qhov kawg kom txo tau qhov kev hloov pauv.
(3) Kev tiv thaiv ntawm thermocouple xov hlau
Thaum txoj kab uas hla ntawm sheathed thermocouple yog tib yam, qhov yuam kev shunt yuav nce raws li qhov tsis kam ntawm cov thermocouple hlau nce. Yog li ntawd, nws yog qhov zoo dua los siv cov khoom me me thermocouple xov hlau. Piv txwv li, piv rau K-hom thermocouples, S-hom armored thermocouples nrog tib txoj kab uas hla yuav txo qhov yuam kev shunt los ntawm 40%. Yog li ntawd, S-hom thermocouples tuaj yeem siv los ntsuas qhov kev faib tawm ntawm qhov cub kub qhov chaw, uas yog tus nqi tab sis qhov tseeb dua.
(4) Rwb thaiv tsev tsis kam
Nyob rau hauv qhov kub thiab txias, qhov resistivity ntawm oxides txo exponentially nrog nce kub. Qhov yuam kev shunt feem ntau yog nyob ntawm cov yam ntxwv ntawm kev rwb thaiv tsev ntawm cov khoom kub-kub. Qhov qis dua qhov rwb thaiv tsev tsis kam, qhov yooj yim dua qhov shunt yuam kev. Thaum lub rwb thaiv tsev tiv thaiv nce 10 npaug los yog txo mus rau 1/10, qhov yuam kev shunt yuav txo mus rau 1/10 lossis 10 zaug. Txhawm rau kom tsis txhob muaj kev sib txawv, cov khoom siv thermocouples yuav tsum tau siv ntau li ntau tau los ua kom cov rwb thaiv tsev tuab. Yog tias cov kev ntsuas saum toj no tsis muaj txiaj ntsig, cov thermocouples sib dhos yuav tsum tau siv.
5. Kev hloov pauv luv luv (K xeev)
K-hom thermocouples, nyob rau hauv qhov kub ntawm 250 degree -600 degree, tsim cov qauv luv luv vim yog cov kev hloov hauv lawv cov microstructure, uas tuaj yeem cuam tshuam rau cov thermoelectric tej zaum thiab qhov yuam kev, hu ua K-state [3]. Qhov no yog qhov tshwj xeeb lattice hloov ntawm Ni Cr alloy. Thaum cov ntsiab lus Cr nyob hauv thaj tsam ntawm 5-30%, muaj kev txiav txim hloov pauv hauv atomic lattice. Cov teeb meem tshwm sim los ntawm kev hloov pauv hauv Cr cov ntsiab lus thiab qhov kub thiab txias. Tshav kub K-hom thermocouple los ntawm 300 degree mus rau 800 degree thiab tshem tawm ntawm qhov taw tes ntawm 50 degree los ntsuas qhov muaj peev xwm. Ntawm 450 degree, qhov sib txawv siab tshaj plaws mus txog 4 degree, thiab nyob rau hauv qhov ntau ntawm 350-600 degree, nws yog qhov zoo sib txawv. Vim tias muaj K-xeev, qhov ntsuas kub nce lossis txias qhov ntsuas ntawm K-hom thermocouples tsis sib haum. Yog li ntawd, nws tau hais meej meej nyob rau hauv qhov kev kuaj xyuas tus nqi qis ntawm cov thermocouple uas qhov kev xeem ua ntu zus yog: ntsuas qhov ntsuas kub ntawm qhov taw tes los ntawm qhov kub qis mus rau qhov kub siab. Tsis tas li ntawd, nyob rau ntawm qhov ntsuas 400 degree, tsis tsuas yog cov cua sov hloov mus rau qhov tsis zoo thiab nws nyuaj rau kev ua tiav thermal equilibrium, tab sis nws kuj tshwm sim nyob rau hauv qhov siab tshaj plaws ntawm K lub xeev yuam kev. Yog li ntawd, ua tib zoo txiav txim seb lub ntsiab lus puas tsim nyog.
Qhov tshwm sim ntawm luv luv txiav txim hloov cov qauv hauv Ni Cr alloys tsis tsuas yog muaj nyob rau hauv K-hom tab sis kuj nyob rau hauv qhov zoo electrode ntawm E-hom thermocouples. Txawm li cas los xij, E-hom thermocouple tsuas yog 2/3 ntawm K-hom raws li kev hloov pauv. Nyob rau hauv luv luv, K lub xeev muaj feem xyuam rau qhov kub thiab txias thiab lub sij hawm, thiab qhov sib txawv yuav hloov tau zoo heev thaum lub kub faib los yog thermocouple txoj hauj lwm hloov. Nws yog ib qho nyuaj rau kev ntsuam xyuas qhov loj ntawm qhov sib txawv.