Cov khoom siv roj ntsha li cas rau cov pa phem thiab phom sij siv hauv kev lag luam?
Nyob rau hauv qhov tseeb, ntau ntawm cov gases ntsib nyob rau hauv kev noj qab haus huv thiab huv si yog sib tov ntawm organic thiab inorganic gases. Vim muaj ntau yam laj thawj, peb txoj kev nkag siab tam sim no ntawm cov pa phem thiab cov pa phem tau tsom mus rau cov pa roj carbon monoxide, cov pa roj uas tuaj yeem ua rau mob hnyav (hydrogen sulfide, hydrogen cyanide, thiab lwm yam), thiab qee cov pa roj carbon monoxide (carbon monoxide), Oxygen thiab lwm yam. cov cuab yeej ntes, yog li ntawd, tsab xov xwm no yuav ua ntej tsom mus rau kev qhia cov cuab yeej no, thiab ua tswv yim rau kev siv ntau yam tshuaj lom thiab teeb meem (inorganic / organic) gas detectors raws li qhov xwm txheej tam sim no.
Kev faib tawm ntawm cov tshuaj lom thiab teeb meem roj ntes thiab cov khoom tseem ceeb ntawm cov khoom siv hluav taws xob qub yog cov khoom siv roj.
Gas sensors tuaj yeem muab faib ua peb pawg hauv txoj cai:
A) Gas sensors siv lub cev thiab tshuaj lom neeg cov khoom: xws li hom semiconductor (nto tswj hom, ntim tswj hom, nto tej yam khoom), hom catalytic combustion, khoom thermal conductivity hom, thiab lwm yam.
B) Gas sensors siv lub cev muaj zog: xws li kev siv hluav taws xob, kev cuam tshuam lub teeb, kev nqus infrared, thiab lwm yam.
C) Gas sensors siv cov khoom siv hluav taws xob: xws li lub peev xwm electrolysis, Galvanic roj teeb, diaphragm ion electrode, tsau electrolyte, thiab lwm yam.
Raws li cov kev phom sij, peb faib cov pa phem thiab cov pa phem rau hauv ob pawg: cov pa taws thiab cov pa phem.
Vim lawv cov khoom sib txawv thiab kev phom sij, lawv txoj kev tshawb nrhiav kuj txawv.
Combustible gas yog cov roj txaus ntshai tshaj plaws nyob rau hauv petrochemical thiab lwm yam kev lag luam. Nws feem ntau yog cov pa roj carbon monoxide xws li alkanes thiab qee cov roj inorganic xws li carbon monoxide. Kev tawg ntawm cov pa hluav taws xob yuav tsum ua tau raws li qee yam xwm txheej, uas yog: qee qhov concentration ntawm cov pa roj combustible, qee cov pa oxygen thiab cov cua sov txaus los ua rau lawv qhov hluav taws kub, cov no yog peb lub ntsiab lus ntawm kev tawg (xws li tawg daim duab peb sab hauv daim duab sab laug. saum toj no), uas ploj lawm ib qho Tsis tau, uas yog hais tias, qhov tsis muaj ib qho ntawm cov xwm txheej no yuav tsis ua rau hluav taws kub thiab tawg. Thaum cov pa hluav taws kub (steam, plua plav) thiab oxygen sib xyaw thiab ncav cuag ib qho kev xav tau, qhov tawg yuav tshwm sim thaum ntsib qhov hluav taws kub nrog qee qhov kub. Peb hu rau qhov concentration ntawm cov roj combustible uas tawg thaum nws ntsib qhov hluav taws kub raws li qhov tawg concentration txwv, hu ua qhov kev txwv tawg, thiab feem ntau qhia hauv feem pua. Qhov tseeb, qhov sib tov no tsis tawg ntawm ib qho kev sib xyaw ua ke tab sis muaj ntau qhov concentration.
Tsis muaj qhov tawg yuav tshwm sim thaum cov pa taws kub hnyiab tau qis dua LEL (Lower Explosive Limit) (tsis txaus cov pa roj carbon dioxide) thiab siab dua UEL (Upper Explosive Limit) (tsis txaus oxygen). LEL thiab UEL ntawm cov roj hluav taws xob sib txawv yog qhov sib txawv (saib qhov kev taw qhia ntawm qhov teeb meem thib yim), uas yuav tsum tau them sai sai rau thaum ntsuas qhov ntsuas. Rau kev nyab xeeb, feem ntau peb yuav tsum tau tshaj tawm lub tswb thaum lub siab ntawm cov roj combustible yog 10 feem pua thiab 20 feem pua ntawm LEL, ntawm no, 10 feem pua LEL txhais tau tias. Raws li lub tswb ceeb toom, thiab 20 feem pua LEL ua lub tswb nrov. Qhov no yog vim li cas peb hu lub combustible gas detector kuj hu ua LEL detector.
Nws yuav tsum tau muab sau tseg tias 100 feem pua ntawm cov LEL ntes tsis tau txhais hais tias cov concentration ntawm cov combustible gas ncav cuag 100 feem pua ntawm cov roj ntim, tab sis mus txog 100 feem pua ntawm cov LEL, uas yog sib npaug rau qhov tsawg tshaj plaws tawg txwv ntawm cov combustible. gas. Yog tias nws yog methane, 100 feem pua ntawm LEL =4 feem pua ntawm cov concentration (VOL). Hauv kev ua haujlwm, lub tshuab ntes uas ntsuas cov pa roj los ntawm LEL yog peb cov khoom siv catalytic combustion detector. Nws lub hauv paus ntsiab lus yog ob txoj kev choj (feem ntau hu ua Wheatstone choj) nrhiav kom pom. Ib qho ntawm cov platinum hlau txuas hniav yog coated nrog cov tshuaj catalytic combustion. Tsis muaj teeb meem dab tsi ntawm cov roj hluav taws xob, tsuav yog nws tuaj yeem raug hluav taws xob los ntawm cov electrodes, qhov kev tiv thaiv ntawm platinum hlau choj yuav hloov vim qhov kub thiab txias. Lub concentration ntawm combustible gas yog nyob rau hauv ib tug tej yam kev faib ua feem, thiab cov concentration ntawm combustible gas yuav xam tau los ntawm lub Circuit Court system thiab microprocessor ntawm lub ntsuas. Thermal conductivity VOL detectors uas ncaj qha ntsuas lub ntim concentration ntawm combustible gases kuj muaj nyob rau hauv lub lag luam. Nyob rau tib lub sijhawm, twb muaj LEL / VOL cov khoom sib xyaw ua ke. Lub VOL flammability detector yog tshwj xeeb tshaj yog haum rau ntsuas volumetric (VOL) concentrations ntawm flammable gases nyob rau hauv anoxic (tsis txaus oxygen) ib puag ncig.
Cov pa phem tuaj yeem muaj nyob tsis tau tsuas yog hauv cov khoom siv raw, xws li cov khoom siv tshuaj lom neeg feem ntau (VOC), tab sis kuj yog cov khoom siv los ntawm ntau yam kev sib txuas hauv cov txheej txheem tsim khoom, xws li ammonia, carbon monoxide, hydrogen sulfide, thiab lwm yam. yog qhov txaus ntshai tshaj plaws rau cov neeg ua haujlwm. Qhov kev puas tsuaj no suav nrog tsis tsuas yog kev puas tsuaj tam sim ntawd, xws li lub cev tsis xis nyob, kab mob, kev tuag, thiab lwm yam, tab sis kuj muaj kev puas tsuaj rau tib neeg lub cev mus ntev, xws li kev tsis taus, mob qog noj ntshav thiab lwm yam. Kev kuaj pom cov pa phem thiab cov pa phem no yog ib qho teeb meem uas peb cov teb chaws tsim kho yuav tsum pib ua tib zoo saib xyuas.
