Ceev Reference: Thermocouple Millivolt Output rau Common Temperature (J, K, T)

Ntau tus kws tshaj lij hauv kev lag luam hluav taws xob cua sov feem ntau pom lawv tus kheej nres los xyuas cov millivolt tso tawm ntawm cov thermocouples ntawm qhov kub thiab txias -tshwj xeeb tshaj yog thaum ntsuas cov khoom siv, kev daws teeb meem tsis zoo, lossis xaiv cov khoom tsim nyog rau ib qhov project. Txawm hais tias nws zoo- kho lub tshuab ua kom sov lossis ua kom muaj qhov ntsuas kub zoo hauv kev teeb tsa kev lag luam, muaj cov ntaub ntawv meej, txhim khu kev qha ntawm cov thermocouple kev ua tau zoo tsis yog- sib tham. Kab lus no rhuav tshem cov ntsiab lus tseem ceeb rau peb hom thermocouple feem ntau (J, K, T), nrog rau kev pom zoo kom tsis txhob muaj kev cuam tshuam ntau.

Thermocouples ua haujlwm ntawm Seebeck nyhuv, qhov twg ob lub hlau sib txawv ntawm ib qho kawg (kev ntsuas qhov sib txuas) tsim kom muaj qhov hluav taws xob me me thaum raug kub qhov sib txawv ntawm qhov sib txuas thiab lwm qhov kawg (qhov kev sib tshuam siv). Cov zis hluav taws xob, ntsuas hauv millivolts (mV), cuam tshuam ncaj qha nrog qhov sib txawv ntawm qhov kub thiab txias, ua rau lawv tseem ceeb rau qhov ntsuas kub hauv cov cua sov. Txhua hom -J, K, T- siv cov hlau sib txawv, ua rau muaj qhov sib txawv ntawm qhov kub thiab txias, qhov tseeb, thiab cov zis millivolt.

Hom J thermocouples, ua los ntawm hlau thiab constantan, yog dav siv nyob rau hauv industrial cua sov daim ntaub ntawv vim lawv pheej yig thiab haum rau nruab nrab kub. Lawv qhov kev khiav hauj lwm muaj kwv yees li ntawm -210℃txog 1200 degree, tab sis kev ua haujlwm qis dua 760℃yog tias raug oxidizing ib puag ncig. Raws li kev paub dhau los, Hom J yog qhov yooj yim rau drift thaum siv nyob rau hauv siab - av noo los yog corrosive chaw, yog li kev tiv thaiv kom zoo yog qhov yuav tsum tau ua. Ntawm qhov ntsuas kub zoo li 25℃(chav kub), Hom J tso tawm ib puag ncig 0.994 mV, nce mus rau 42.919 mV ntawm 750℃- qhov txwv sab saud rau kev siv txhim khu kev qha hauv cov cua sov feem ntau.

Hom K, muaj li ntawm chromel thiab alumel, yog qhov kev xaiv zoo tshaj plaws hauv cov hluav taws xob cua sov. Nws tuav ntau qhov kub thiab txias (-270℃txog 1372 degree) thiab muaj kev ruaj ntseg zoo dua nyob rau hauv ob qho tib si oxidizing thiab inert atmospheres piv rau Hom J.实际上, Hom K yog qhov mus- xaiv rau feem ntau cov lag luam thiab cov khoom siv cua sov, los ntawm hluav taws xob boilers rau radiant cua sov systems. Ntawm 100 degree, nws cov zis yog kwv yees li 4.096 mV, thiab ntawm 1000 degree, nws ncav cuag 41.276 mV. Ib daim ntawv tseem ceeb: Hom K tuaj yeem ntsib "ntsuab rot" hauv kev txo cov huab cua (tsawg oxygen), uas cuam tshuam kev nyeem ntawv thiab ua rau lub neej luv - zam qhov chaw ib puag ncig tshwj tsis yog siv lub hnab tiv thaiv.

Hom T thermocouples, ua los ntawm tooj liab thiab constantan, ua tau zoo nyob rau hauv qis - daim ntawv thov kub, ua rau lawv zoo tagnrho rau cov tub yees -raws li cua sov systems los yog txias- huab cua ntsuas kub. Lawv qhov ntau yog -270℃txog 400 degree, nrog qhov raug siab ntawm sub-zero kub. Tsis zoo li Hom J thiab K, Hom T yog resistant rau ya raws thiab me ntsis corrosion, ua rau nws haum rau sab nraum zoov los yog damp installation. Ntawm 0℃(qhov ntsuas kub rau ntau qhov ntsuas), nws cov zis yog 0 mV-zoo rau kev kuaj xyuas hauv paus. Ntawm 200 degree, nws outputs 9.286 mV, thiab ntawm -50 degree, nws poob mus rau -2.035 mV. Raws li kev paub dhau los, Hom T yuav tsum tsis txhob siv siab dua 400 degree, vim tooj liab oxidation nrawm nrawm, ua rau kev puas tsuaj tsis tuaj yeem.

Thaum ua hauj lwm nrog thermocouple millivolt outputs, ob peb lub tswv yim txiav txim siab tiv thaiv tus nqi yuam kev. Ib txwm paub meej tias qhov ntsuas kub ntawm qhov sib txuas- feem ntau cov qauv qauv xav tias 0 degree, yog li qhov ntsuas kub hloov pauv tuaj yeem cuam tshuam kev nyeem ntawv. Kev siv ib qho kev sib txuas lus sib txuas lus los yog tus tswj hwm nrog ua - hauv kev them nyiaj yog pom zoo. Tsis tas li ntawd, xyuas kom muaj kev rwb thaiv tsev zoo; Cov rwb thaiv tsev tsis sib haum lossis puas tuaj yeem ua rau hluav taws xob cuam tshuam, ua rau kev nyeem millivolt tsis raug.

Lwm lub ntsiab lus tseem ceeb yog calibration zaus. Thermocouples ib txwm drift dhau lub sij hawm vim hlau qaug zog thiab ib puag ncig raug, yog li lub sij hawm calibration tiv thaiv tus qauv ntawv pov thawj kom ntseeg tau cov ntaub ntawv. Rau cov tshuab cua sov ua haujlwm ntawm qhov kub thiab txias los yog hauv cov xwm txheej hnyav, calibration txhua 6 mus rau 12 lub hlis yog pom zoo. Tsis txhob cia siab rau ib leeg ntawm cov lus millivolt nkaus xwb-chaw tsim khoom- cov ntaub ntawv tshwj xeeb rau cov qauv ntsuas thermocouple feem ntau suav nrog kev hloov pauv hloov pauv kom raug zoo dua.

Kev nkag siab txog cov thermocouple millivolt outputs rau qhov kub thiab txias yog lub hauv paus rau kev txhim khu kev qha cua sov ua haujlwm, txawm tias xaiv cov khoom, teeb meem daws teeb meem, lossis cov cuab yeej ntsuas ntsuas. Hom J, K, thiab T txhua tus muaj qhov sib txawv thiab cov kev txwv, yog li kev sib piv cov thermocouple hom rau daim ntawv thov qhov kub thiab txias ib puag ncig yog qhov tseem ceeb rau kev ua haujlwm zoo. Kev txhim kho kom zoo, rwb thaiv tsev, siv kev sib txuas them nyiaj, thiab kev ntsuas tsis tu ncua ntxiv kom ntseeg tau tias kev nyeem ntawv zoo ib yam.

Rau cov tshuab cua sov uas xav tau kev tswj xyuas qhov kub thiab txias -los ntawm cov chaw tsim khoom siv rau kev lag luam HVAC teeb tsa- xaiv cov thermocouple kom raug thiab txhais cov lus tso tawm nteg lub hauv paus rau kev ua haujlwm thiab kev nyab xeeb. Kev cai cua sov cov kev daws teeb meem feem ntau xav tau kev sib xyaw ua ke thermocouple, qhov kev txawj ntse hauv kev sib piv millivolt tso zis yuav tsum tau rau cov kev qhia tshwj xeeb kom ua tau zoo. Kev soj ntsuam ntawm cov kev xav tau ntawm daim ntawv thov, suav nrog qhov kub thiab txias, ib puag ncig, thiab cov hom phiaj raug, pab txheeb xyuas qhov zoo tshaj plaws thermocouple hom thiab teeb tsa rau lub sijhawm ntev - kev ntseeg tau.