HEPA

HEPA (/ˈhɛpə/, iska mai inganci mai inganci) tacewa,  wanda aka fi sani da babban ingantaccen matattarar kamawa,  shine ingantaccen ma'auni na matattarar iska. 

Filters da suka hadu da ma'auni na HEPA dole ne su gamsu da wasu matakan inganci. Ka'idoji na yau da kullun suna buƙatar cewa tace iska ta HEPA dole ne ta cire - daga iska da ke rufewa ta - aƙalla 99.95% (ISO, European Standard)   ko 99.97% (ASME, US DOE)   na barbashi wanda diamita ya yi daidai da 0.3 μm, tare da ingancin tacewa yana ƙaruwa don diamita na barbashi ƙasa da kuma mafi girma fiye da 0.3μm. Filters na HEPA suna kama pollen, datti, ƙura, danshi, kwayoyin cuta (0.2-2.0 μm), ƙwayoyin ƙwayoyin halitta (0.02-0.3 μm), da kuma submicron ruwa aerosol (0.02-0,5 μm).   Wasu microorganisms, alal misali, Aspergillus niger, Penicillium citrinum, Staphylococcus epidermidis, da Bacillus subtilis ana kama su ta hanyar filters na HEPA tare da photocatalytic oxidation (PCO). A HEPA tace kuma iya kama wasu ƙwayoyin cuta da ƙwayoyin ƙwayoyin halitta waɗanda suke ≤0.3 μm. A HEPA tace kuma iya kama bene ƙurar wanda ya ƙunshi bacteroidia, clostridia, da bacilli. An sayar da HEPA a cikin shekarun 1950, kuma asalin kalmar ya zama Alamar kasuwanci mai rijista kuma daga baya alamar kasuwanci ta gaba ɗaya don matattarar da ta dace sosai. Ana amfani da matattarar HEPA a cikin aikace-aikacen da ke buƙatar kula da gurɓataccen, kamar ƙera kayan aiki, na'urorin kiwon lafiya, semiconductors, nukiliya, abinci da samfuran magunguna, da kuma asibitoci, gidaje, da motoci.   

 Hanyar aiki 
alt=Four diagram each showing the path of small particle as it approaches a large fiber according to each of the four mechanisms|thumb|Hanyoyin tattara matattarar matattarar guda huɗu: watsawa, tsayarwa, tasirin inertial, da jan hankali na electrostatic (hanyar iska daga hagu zuwa dama) 
alt=|thumb|400x400px|Kyakkyawan Kayan Tattalin Arziki na Classic tare da Tsarin Tattalin Filter
Matatun HEPA sun ƙunshi tabarma na zaruruwa da aka shirya ba da gangan ba. Filayen yawanci sun ƙunshi polypropylene ko fiberglass tare da diamita tsakanin 0.5 zuwa 2.0 micrometers. Yawancin lokaci, waɗannan matattarar suna kunshe ne da ƙuƙumman daure masu kyau. Waɗannan zaruruwa suna haifar da ƙunƙuntacciyar hanya mai murƙushe wacce iska ke wucewa. Lokacin da mafi girman ɓangarorin ke wucewa ta wannan hanyar, ɗimbin zaruruwa suna yin aiki kamar sieve ɗin dafa abinci wanda a zahiri ya toshe ɓangarorin wucewa. Duk da haka, lokacin da ƙananan barbashi suka wuce tare da iska, yayin da iska ke juyawa da juyawa, ƙananan ƙwayoyin ba za su iya ci gaba da motsi na iska ba don haka suna yin karo da zaruruwa. Ƙananan barbashi suna da ƙarancin rashin ƙarfi kuma suna motsawa ba tare da izini ba sakamakon karo da ƙwayoyin iska guda ɗaya (Motsi na Brown). Saboda motsin su, suna ƙarewa cikin zaruruwa. Mahimman abubuwan da suka shafi ayyukansa sune diamita na fiber, kauri mai tacewa, da saurin fuska, wanda shine auna saurin iska a mashigar ko mashigar tsarin dumama iska da kwandishan (HVAC). Ana auna saurin fuska a cikin m/s kuma ana iya ƙididdige shi azaman ƙimar ƙarar ƙarar (m3/s) ta raba wurin fuska (m2). Tazarar iska tsakanin filaye masu tace HEPA yawanci ya fi 0.3 μm. Ba kamar sieves ko matattarar membrane ba, inda ɓangarorin da ke ƙasa da buɗewa ko pores za su iya wucewa, an ƙera matatun HEPA don yin niyya da nau'ikan girman barbashi. Wadannan barbashi sun makale (suna manne da fiber) ta hanyar hadewar hanyoyin guda uku masu zuwa:

 Rarraba; barbashi da ke ƙasa da 0.3 μm ana kama su ta hanyar watsawa a cikin tace HEPA. Wannan hanyar ta samo asali ne daga haɗuwa da kwayoyin gas ta ƙananan barbashi, musamman waɗanda ke ƙasa da 0.1 μm a diamita. Ana hura ƙananan barbashi yadda ya kamata ko kuma suna juyawa a kusa da su kuma suna haɗuwa da fiber na kafofin watsa labarai. Wannan hali yayi kama da Motsi na Brownian kuma yana haɓaka yiwuwar cewa za a dakatar da ƙwayoyin ta hanyar tsayarwa ko tasiri; wannan hanyar ta zama mai rinjaye a ƙananan iska.  
 Tsayarwa; barbashi da ke bin layin kwarara a cikin iska suna zuwa cikin radius ɗaya na fiber kuma suna manne da shi. Ana kama ƙwayoyin matsakaicin girman ta wannan tsari.
 Tasiri; manyan barbashi ba su iya kauce wa fiber ba ta hanyar bin tsarin iska mai laushi kuma an tilasta su shiga cikin ɗaya daga cikinsu kai tsaye; wannan tasirin yana ƙaruwa tare da raguwar fiber da saurin iska mai girma.

Rarrabawar ta fi yawa a ƙasa da girman ƙwayoyin 0.1 μm diamita, yayin da tasiri da tsayarwa suka fi yawa sama da 0.4 μm. A tsakanin, kusa da girman ƙwayoyin da suka fi shiga (MPPS) 0.21 μm, duka watsawa da tsayarwa ba su da inganci. Saboda wannan shine mafi rauni a cikin aikin tacewa, ƙayyadaddun HEPA suna amfani da riƙe barbashi kusa da wannan girman (0.3 μm) don rarraba tacewa. Koyaya yana yiwuwa ga barbashi karami fiye da MPPS ba su da ingancin tacewa mafi girma fiye da na MPPS. Wannan ya faru ne saboda gaskiyar cewa waɗannan barbashi na iya aiki a matsayin wuraren nucleation don mafi yawan kwantar da hankali da samar da barbashi kusa da MPPS.