Gas sensors tuaj yeem muab faib ua peb pawg loj raws li lawv txoj haujlwm ua haujlwm:
1. Gas sensors siv lub cev thiab tshuaj lom neeg, xws li hom semiconductor (surface manipulation type, ntim manipulation type, deg tej yam ntxwv), hom catalytic incineration, khoom thermal conductivity hom, thiab lwm yam.
2. Gas sensors siv lub cev muaj zog, xws li thermal conductivity, optical drying, infrared absorption, thiab lwm yam.
3. Gas sensors siv cov khoom siv hluav taws xob, xws li lub peev xwm electrolysis, galvanic cell, barrier ion electrode, tsau electrolyte, thiab lwm yam.
Raws li kev puas tsuaj, peb faib cov pa phem thiab cov pa phem rau hauv ob pawg: cov pa hluav taws xob thiab cov pa phem. Vim lawv qhov xwm txheej thiab kev puas tsuaj txawv, lawv txoj kev tshuaj xyuas kuj txawv.
Combustible gases feem ntau ntsib raws li cov pa phem hauv kev lag luam xws li petrochemicals. Lawv feem ntau muaj cov pa roj carbon monoxide xws li alkanes thiab qee cov roj inorganic xws li carbon monoxide.
Kev tawg ntawm combustible gases yuav tsum tau tej yam kev mob, xws li: ib tug tej yam concentration ntawm combustible gases, ib tug npaum li cas ntawm cov pa oxygen, thiab ib tug qhov chaw ntawm hluav taws uas yuav ignite lawv nrog tshav kub. Cov no yog peb lub ntsiab lus tseem ceeb ntawm kev tawg, thiab tsis muaj ib qho tseem ceeb. Hauv lwm lo lus, ib qho ntawm cov xwm txheej no yuav tsis ua rau hluav taws kub lossis tawg. Thaum cov roj hluav taws xob (steam, plua plav) thiab cov pa oxygen sib tov thiab ncav cuag ib qho concentration, lawv yuav tawg thaum raug hluav taws kub nrog qee qhov kub. Peb xa mus rau qhov concentration ntawm combustible gases uas tuaj yeem tawg thaum raug hluav taws kub raws li qhov tawg concentration txwv, abbreviated li explosion txwv, uas feem ntau yog qhia nyob rau hauv%. Hauv kev xyaum, qhov sib xyaw no tsis tas yuav tawg ntawm qhov sib tov sib xyaw thiab yuav tsum muaj qhov ntsuas qhov ntsuas.
Cov nqi lag luam wholesale ntawm cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob tsis zoo: Kev tawg yuav tsis tshwm sim thaum qhov siab ntawm cov pa hluav taws xob qis qis dua LEL (tsawg kawg qhov txwv) (tsis muaj roj combustible concentration) thiab thaum nws cov concentration siab dua UEL (qhov siab tshaj plaws tawg) (tsis muaj oxygen). Lub LEL thiab UEL ntawm cov roj hluav taws xob sib txawv kuj sib txawv, uas yuav tsum tau ua tib zoo saib xyuas thaum ntsuas ntsuas ntsuas. Rau cov laj thawj kev nyab xeeb, feem ntau peb yuav tsum tshaj tawm lub tswb thaum lub zog ntawm cov roj hluav taws xob yog 10% thiab 20% ntawm LEL, qhov twg 10% LEL raug xa mus. Ua qhov ceeb toom ceeb toom, thaum 20% LEL hu ua kev ceeb toom kev pheej hmoo. Qhov no kuj yog lub hauv paus ntawm peb lub tshuab hluav taws xob hluav taws xob, tseem hu ua LEL detector.
Cov nqi lag luam wholesale ntawm cov khoom siv tshuaj lom neeg thiab cov pa phem tsis zoo: Nws yuav tsum tau qhia meej tias 100% tso tawm ntawm LEL ntes tsis yog qhov concentration ntawm cov roj combustible mus txog 100% ntawm cov roj ntim, tab sis ncav cuag 100% ntawm LEL, uas yog sib npaug rau qhov qis qis qis qis ntawm cov roj combustible. Yog tias nws yog methane, 100% LEL=4% ntim concentration (VOL). Hauv kev ua haujlwm tom tsev, ntsuas nrog LEL txoj kev yog ib qho kev siv tshuaj tua kab mob catalytic incineration. Nws lub hauv paus ntsiab lus yog tus choj ob (feem ntau hu ua Wheatstone choj) kuaj xyuas. Cov tshuaj catalytic incineration yog coated rau ntawm tus choj platinum hlau nyob nruab nrab. Txawm hais tias cov roj hluav taws xob tsis zoo, tsuav nws tuaj yeem raug hluav taws xob los ntawm electrode, qhov kev tiv thaiv ntawm platinum hlau choj yuav hloov vim qhov kub thiab txias. Qhov kev hloov pauv no yog proportional rau qhov concentration ntawm cov roj hluav taws xob, thiab qhov concentration ntawm cov roj hluav taws xob tuaj yeem xam los ntawm lub ntsuas hluav taws xob thiab microprocessor. Thermal conductivity VOL detectors uas ncaj qha ntsuas lub ntim concentration ntawm combustible gases kuj muaj nyob rau hauv lub lag luam, thiab tam sim no muaj LEL / VOL integrated detectors muaj. Lub VOL combustible detector yog tshwj xeeb tshaj yog haum rau ntsuas qhov ntim (VOL) concentration ntawm combustible gases nyob rau hauv ib puag ncig tsis muaj oxygen.
