Yuav ua li cas yog LEL%, VOL%, thiab ppm hloov dua siab tshiab nyob rau hauv gas detectors
Thaum siv cov cuab yeej siv roj hauv lub neej niaj hnub, qhov kev tshawb nrhiav ntau yam ntawm cov kua siv lead ua kua ntawm lub ntsuas roj feem ntau tshwm nrog cov lus xws li 0-100LEL% lossis 0-2000ppm, lossis nrog cov lus xws li VOL% lossis ppm . Dab tsi yog lub ntsiab lus tshwj xeeb ntawm peb chav nyob thiab lawv hloov siab los ntseeg li cas?
01
VOL% (gas ntim feem pua)
VOL yog lub cev lub cev uas piav qhia txog qhov ntim ntawm cov pa, qhia tias feem pua, uas sawv cev rau feem pua ntawm cov pa tshwj xeeb hauv huab cua. 5% VOL methane sawv cev rau 5% ntawm qhov ntim ntawm methane hauv huab cua.
Kev tshawb nrhiav ntau yam ntawm cov khoom siv roj av feem ntau qhia tau tias yog VOL%, piv txwv li, qhov kev tshawb pom ntau yog 0-100% VOL, uas txhais tau hais tias qhov ntsuas roj no tuaj yeem ntes tau qee cov pa hauv huab cua nrog qhov feem ntau ntawm {{1 }}%.
Peb kuj tuaj yeem teeb tsa tus nqi feem pua ntawm VOL raws li lub tswb. Thaum cov ntsiab lus ntawm qee yam roj mus txog lossis tshaj qhov teeb tsa no, lub ntsuas roj yuav suab lub tswb. Qhov no suav nrog lwm chav, LEL%.
02
LEL% (qis dua qhov txwv)
Cov pa roj carbon monoxide yog cov roj sib xyaw ua ntej uas tuaj yeem sib xyaw nrog huab cua (lossis oxygen) nyob rau hauv ib qho kev concentration ntau. Thaum nws ntsib qhov hluav taws kub, nws yuav tawg. Qhov tsawg kawg nkaus ntim feem pua ntawm cov roj no tuaj yeem tawg hauv huab cua yog LEL%, tseem hu ua qhov txwv qis dua. Qhov concentration ntawm cov roj ntim ntawm qhov qis tawg txwv yog qhia hauv LEL%, uas yog qhia hauv feem pua. Ntawd yog, qhov kev txwv qis qis tau muab faib ua 100 ntu, nrog rau txhua chav yog 1 LEL%.
03
PPM (ib feem ntawm ib lab ntawm cov roj ntim feem pua)
Lub tswv yim ntawm PPM zoo ib yam li VOL, tshwj tsis yog tias PPM sawv cev rau ib lab ntawm cov roj ntim.
Piv txwv li, 10ppm ntawm cov pa roj carbon dioxide yog hais txog cov huab cua uas muaj 10 feem ntawm ib lab ntawm cov pa roj carbon dioxide, vim tias chav tsev PPM yog chav tsev tsis muaj qhov dav.
"Non dimensional unit" yog ib lub ntsiab lus tshwj xeeb hauv astronomy, uas suav nrog pi, ntuj tas li (e), radians (rad), thiab golden ratio (φ) Thiab tus txheeb ze molecular hnyav (Mr), thiab lwm yam. Ntawm qhov tsis sib xws, muaj qhov loj me. cov khoom uas muaj units xws li ntev, cheeb tsam, lub sij hawm, thiab lwm yam.
Tsis muaj qhov loj me feem ntau sau ua cov khoom lossis qhov sib piv ntawm ob qhov loj me, tab sis lawv qhov kawg qhov ntev tshem tawm ib leeg, ua rau tsis muaj qhov ntau.
Gas detectors muaj peev xwm soj ntsuam PPM theem yog tag nrho cov siv los soj ntsuam cov pa micro leaks nyob rau hauv lub chaw ua hauj lwm, raws li cov pa micro leaks yog heev txaus ntshai thiab ntev mus ntev gas micro leaks tej zaum yuav ua rau muaj teeb meem loj. Yog li ntawd, nws yog ib qho tsim nyog yuav tsum tau siv PPM qib roj ntsuas ntsuas kom pom thiab tshem tawm cov xau micro hauv lub sijhawm.
04
Kev hloov pauv ntawm VOL%, LEL%, thiab PPM
Ua ntej, muaj kev hloov pauv ntawm VOL thiab PPM. Kev hloov pauv ntawm ob chav nyob no yog qhov yooj yim, raws li % VOL yog feem pua ntawm cov ntim, thaum PPM yog qhov ib lab ntawm ntim. Yog li ntawd, 1% VOL=10000PPM.
Qhov thib ob, kev hloov pauv ntawm VOL thiab LEL yuav tsum xub txheeb xyuas qhov kev txwv qis ntawm cov roj combustible. Thaum lub concentration ntawm cov roj combustible nyob rau hauv cov huab cua mus txog nws qis explosive txwv, peb hu lub explosion txaus ntshai ntawm combustible gas ib puag ncig nyob rau hauv qhov chaw no 100%. Piv txwv li, LEL ntawm hydrogen yog 4% VOL, uas txhais tau hais tias thaum nws qhov ntim feem pua ntawm cov huab cua mus txog 4% VOL, nws yuav tawg thaum raug nplaim taws. Yog li ntawd, xav txog 4% VOL li 100% txaus ntshai, nws yog hu ua 100% LEL, uas txhais tau tias 4% VOL=100% LEL. Yog li ntawd, 1% VOL=25% LEL.
Qhov thib peb yog kev hloov pauv ntawm PPM thiab LEL, uas tsis tuaj yeem hloov pauv ncaj qha. LEL yuav tsum tau hloov mus rau VOL ua ntej, thiab tom qab ntawd mus rau PPM.
Nov yog ib qho formula: PPM=% LEL x LEL (vol%) x 100
Noj methane ua piv txwv, PPM ntawm 20% LEL methane yog dab tsi? Raws li cov qauv kev suav, 20 (% LEL) x 1 (% VOL) x 100=2000PPm.
Feem ntau hais lus, cov khoom siv roj av uas tuaj yeem ntes PPM yog qhov tseeb heev, thaum LEL roj ntes tau feem ntau siv rau hauv cov xwm txheej tawg, thiab qhov kev txiav txim ntawm qhov loj ntawm VOL yog qhov loj tshaj plaws ntawm lawv, uas kuj tau siv ntau heev.
