Yuav ua li cas los txiav txim seb Hom B thiab Hom J thermocoupldshave ua tsis tiav

Kev txiav txim siab tsis ua hauj lwm ntawm Hom B thiab Hom J thermocouples yuav tsum muaj kev ntsuam xyuas zoo los txiav txim siab txog lawv cov khoom siv, ib puag ncig kev ua haujlwm, thiab cov qauv kev sim. Feem ntau, Hom B thermocouple tsis ua haujlwm tshwm sim feem ntau yog siab -kub drift, paug thiab embrittlement, thiab lub teeb liab tsis muaj zog, thaum Hom J thermocouple tsis ua haujlwm feem ntau pom nyob rau hauv oxidation puas, corrosion luv circuits, thiab txawv txav thermoelectric peev xwm. Cov hauv qab no yog ib txoj hauv kev rau kev ntsuam xyuas:

I. Cov tsos mob thiab kev tshuaj xyuas tus qauv

1. Hom B Thermocouples (Platinum-Rhodium 30-Platinum-Rhodium 6)

Kev Tiv Thaiv Tube Txheej Txheem: Tshawb xyuas lub corundum lossis siab -purity alumina tiv thaiv raj rau cov kab nrib pleb, perforations, los yog hmoov, tshwj xeeb tshaj yog nyob rau hauv qhov cub uas muaj qhov kub thiab txias tsis tu ncua, qhov thermal stress tuaj yeem ua rau tawg yooj yim.

Kev Saib Xyuas Hlau: Yog tias lub raj tiv thaiv puas lawm, tev nws qhib thiab saib seb puas yog ob lub platinum -rhodium hlau tau ua nkig, blackened, los yog qhia "pockmarked" paug, qhia tias raug hlau vapor lossis carbon deposition.

Kev tshuaj xyuas lub rooj vag: Tshawb xyuas seb cov terminals puas yog oxidized thiab blackened, seb cov kab hluav taws xob rwb thaiv tsev puas muaj hnub nyoog, thiab seb cov pob qij txha puas tau detached.

2. Hom J Thermocouple (Iron-Constantan)

Iron Positive Electrode Oxidation: Ua tib zoo xyuas seb cov hlau zoo electrode yog xim liab -kub, xeb, los yog nkig, tshwj xeeb tshaj yog tom qab siv ntev tshaj 500 degree, vim nws muaj oxidation thiab tawg.

Constantan Negative Electrode Corrosion: Hauv cov av noo lossis sulfur-ib puag ncig, constantan (tooj liab-nickel alloy) yog yooj yim corroded, manifesting raws li ib tug greenish nto los yog blistering.

Terminals: Tshawb xyuas cov dej noo nkag uas tuaj yeem ua rau corrosion lossis luv luv ntawm cov terminals.

Lus Cim: Hom J thermocouples ua tau zoo dua li lwm lub hauv paus hlau thermocouples hauv kev txo cov huab cua, tab sis yog tias pom qhov teeb meem tsis ruaj khov, hlau electrode oxidation yuav tsum tau kuaj ua ntej.

II. Kev Ntsuas Hluav Taws Xob

1. Kev ntsuas txuas ntxiv (Multimeter Ohmmeter Range)

Tshem tawm ntawm lub 'meter' thiab ntsuas qhov tsis kam ntawm ob lub terminals:

Tus nqi ib txwm: Ob hom B thiab Hom J thermocouples yuav tsum yog ob peb ohms txog kaum ohms (nyob ntawm qhov ntev thiab txoj kab uas hla);

Qhib Circuit Court: Infinite kuj → Thermocouple hlau tawg, xav tau kev hloov;

luv Circuit Court: Kuj ze rau 0Ω → Internal luv Circuit Court los yog ya raws, xav tau kom qhuav los yog hloov.

Lus Cim: Hom B thermocouples muaj lub teeb liab tsis muaj zog thiab muaj kev cuam tshuam rau kev xaim tsis zoo. Xyuas kom cov terminals tau ruaj ntseg fastened.

2. Thermoelectric Potential Measurement (Millivoltmeter Method)

Siv lub siab - precision millivoltmeter los ntsuas qhov txias hlws ris tso zis thiab muab piv nrog lub calibration table:

Hom B: Theoretical thermoelectric peev xwm ntawm 1000℃yog kwv yees li 4.8mV. Yog tias qhov ntsuas tus nqi sib txawv los ntawm ntau dua ± 0.1mV, nws yuav muaj kev laus lossis kis kab mob.

Hom J: Theoretical tus nqi yog kwv yees li 5.0mV ntawm 100 degree. Yog tias nws qis dua 4.5mV, nws qhia tau hais tias lub thermocouple hlau tau deteriorated los yog oxidized heev.

Kev pom zoo: Muab cov thermocouple nyob rau hauv kev sim thiab ib lub thermocouple tshiab ntawm tib tus qauv ib txhij nyob rau hauv qhov chaw kub thiab txias (xws li cov roj da dej) thiab sib piv cov zis sib txawv los txiav txim seb nws puas ua tsis tau.

III. Kev ntsuas qhov ntsuas kub tiag tiag

1. Kev sib piv qhov kub thiab txias ib puag ncig

Ntxig lub thermocouple rau hauv qhov kub thiab txias tsis tu ncua ntawm qhov ntsuas kub (xws li cov dej kub npau npau ntawm 100℃, lossis roj da dej ntawm 300℃) thiab muab piv nrog tus qauv platinum tiv thaiv tus pas ntsuas kub:

Yog tias qhov sib txawv ntawm qhov kub thiab txias tshaj qhov raug cov chav kawm (Type B ± 0.25% t, Hom J ± 2.5 degree), thiab cov xov hluav taws xob raug txiav tawm, nws tuaj yeem txiav txim siab ua tsis tiav.

2. Dynamic Heating Test

Maj mam ua kom sov thiab sau cov thermoelectric tej zaum hloov:

Yog tias lub teeb liab tsis hloov lossis hloov pauv thaum lub sijhawm cua sov → kev sib cuag tsis zoo;

Yog tias nws tsis tuaj yeem rov qab mus rau xoom tom qab txias → irreversible annealing lossis oxidation puas tau tshwm sim rau lub thermocouple hlau.

IV. Cov yam ntxwv ua tsis tiav hauv cov xwm txheej tshwj xeeb

Rooj	Scenario	Hom B Thermocouple Failure yam ntxwv	Hom J Thermocouple Failure yam ntxwv
High -Tub kub Oxidation Ib puag ncig	Ntev -lub sij hawm ruaj khov, tab sis yog tias lub raj tiv thaiv tsis ua haujlwm, lub thermocouple hlau yog yooj yim kis thiab ua nkig.	Cov hlau cathode oxidizes sai heev, thiab lub neej luv luv qis dua 500 degree.
Txo Atmosphere (H₂, CO)	Ncua rau "platinum embrittlement," ua rau lub thermocouple hlau ua nkig thiab tawg.	Yuav siv tau ib txwm, qhov no yog nws qhov zoo tshaj plaws scenario.
Sulfur{0}}Containing/Vumid Environment	rhiab heev rau kev sib kis, yooj yim tsim tsawg - melting -point eutectic	Constantan yooj yim corroded, ua rau lub teeb liab drift los yog luv luv circuits.
Nquag Thermal Cycling	Thermal stress ua rau lub raj tiv thaiv tawg, nthuav tawm cov thermocouple hlau	High mechanical zog thiab muaj zog vibration kuj.

Kev pom zoo: Hom B yog haum rau huv, siab - qhov kub thiab txias; Hom J yog haum rau nruab nrab- thiab qis- qhov chaw muaj qhov kub thiab txias, tab sis siab - kub oxidation thiab sulfidation ib puag ncig yuav tsum zam.