Capillary dispensers feem ntau yog siv hauv kev lag luam hauv tsev thiab kev lag luam me me qhov twg cov cua sov ntawm cov evaporator yog me ntsis tas li.Cov tshuab no kuj muaj qis qis qis qis thiab feem ntau siv hermetic compressors.Cov neeg tsim khoom siv capillaries vim lawv qhov yooj yim thiab tus nqi qis.Tsis tas li ntawd, feem ntau cov tshuab uas siv cov capillaries raws li qhov ntsuas ntsuas tsis tas yuav tsum muaj lub siab-sab receiver, ntxiv txo nqi.
Capillary tubes tsis muaj dab tsi ntau tshaj li cov raj ntev ntawm txoj kab uas hla me me thiab qhov ntev ruaj khov nruab nrab ntawm lub condenser thiab evaporator.Lub capillary ua tau ntsuas cov tub yees los ntawm lub condenser mus rau evaporator.Vim qhov loj ntev thiab txoj kab uas hla me me, thaum lub tub yees ntws los ntawm nws, cov dej sib txhuam thiab kev poob siab tshwm sim.Qhov tseeb, raws li cov kua dej subcooled ntws los hauv qab ntawm cov condenser los ntawm cov capillaries, qee cov kua yuav boils thaum muaj cov kev poob siab.Cov kev poob siab no coj cov kua hauv qab nws lub siab saturation ntawm nws qhov kub thiab txias ntawm ob peb lub ntsiab lus raws capillary.Qhov blinking no yog tshwm sim los ntawm kev nthuav dav ntawm cov kua thaum lub siab poob.
Qhov loj ntawm cov kua flash (yog tias muaj) yuav nyob ntawm qhov degree ntawm supercooling ntawm cov kua los ntawm lub condenser thiab capillary nws tus kheej.Yog hais tias cov kua flashing tshwm sim, nws yog ntshaw kom lub flash yuav ze li ntawm lub evaporator li sai tau los xyuas kom meej qhov zoo tshaj plaws kev ua tau zoo ntawm lub system.Qhov txias dua cov kua los ntawm hauv qab ntawm lub condenser, cov kua dej tsawg dua los ntawm cov capillary.Lub capillary feem ntau yog coiled, dhau los ntawm los yog welded rau cov kab suction rau ntxiv subcooling los tiv thaiv cov kua hauv capillary los ntawm boiling.Vim tias cov capillary txwv thiab ntsuas cov kua ntws mus rau lub evaporator, nws yuav pab tswj lub siab poob siab uas yuav tsum tau ua kom lub cev ua haujlwm kom zoo.
Lub raj capillary thiab compressor yog ob yam khoom uas cais cov siab siab sab ntawm sab qis ntawm lub tub yees.
Lub raj capillary txawv ntawm qhov nthuav dav valve metering ntaus ntawv nyob rau hauv uas nws tsis muaj qhov txav thiab tsis tswj lub superheat ntawm cov evaporator nyob rau hauv ib qho kev kub ceev load.Txawm tias tsis muaj qhov txav mus los, cov hlab ntsha capillary hloov pauv tus nqi raws li cov evaporator thiab / lossis condenser system siab hloov.Qhov tseeb, nws tsuas yog ua tiav qhov kev ua tau zoo thaum lub siab ntawm sab siab thiab qis yog ua ke.Qhov no yog vim lub capillary ua haujlwm los ntawm kev siv lub siab sib txawv ntawm qhov siab thiab qis siab sab ntawm lub tub yees.Raws li qhov sib txawv ntawm qhov siab thiab qis ntawm qhov system nce, cov tub yees txaus yuav nce.Capillary hlab ua haujlwm txaus siab dhau ntau qhov kev poob siab, tab sis feem ntau tsis ua haujlwm zoo.
Txij li thaum lub capillary, evaporator, compressor thiab condenser txuas nrog hauv series, tus nqi ntws hauv capillary yuav tsum sib npaug rau lub twj tso kua mis qis ntawm compressor.Qhov no yog vim li cas lub laij lej ntev thiab txoj kab uas hla ntawm cov capillary ntawm kev ntsuas evaporation thiab condensation pressures yog qhov tseem ceeb thiab yuav tsum sib npaug rau lub twj tso kua mis hauv tib lub qauv tsim.Ntau dhau lawm nyob rau hauv lub capillary yuav cuam tshuam nws tsis kam mus ntws thiab ces cuam tshuam qhov sib npaug ntawm lub system.
Yog tias lub capillary ntev dhau lawm thiab tiv taus ntau dhau, yuav muaj kev txwv hauv zos.Yog tias txoj kab uas hla me dhau los yog muaj ntau dhau lawm thaum winding, lub peev xwm ntawm lub raj yuav tsawg dua li ntawm lub compressor.Qhov no yuav ua rau tsis muaj roj nyob rau hauv lub evaporator, uas ua rau muaj kev nqus siab tsawg thiab kub dhau heev.Nyob rau tib lub sijhawm, cov kua dej subcooled yuav ntws rov qab mus rau lub condenser, tsim kom muaj lub taub hau siab dua vim tias tsis muaj lub tshuab txais los tuav lub tub yees.Nrog lub taub hau siab dua thiab qis dua nyob rau hauv lub evaporator, tus nqi ntawm cov tub yees yuav nce ntxiv vim qhov siab dua qhov poob ntawm lub raj capillary.Nyob rau tib lub sijhawm, compressor kev ua tau zoo yuav txo qis vim qhov sib piv compression ntau dua thiab qis dua volumetric efficiency.Qhov no yuav yuam kom lub kaw lus sib npaug, tab sis ntawm lub taub hau siab dua thiab qis dua evaporation siab tuaj yeem ua rau tsis tsim nyog.
Yog hais tias lub capillary tsis kam yog tsawg tshaj li qhov yuav tsum tau vim yog luv luv los yog txoj kab uas hla loj dhau, tus nqi ntawm cov tub yees yuav ntau dua li lub peev xwm ntawm lub twj tso kua mis compressor.Qhov no yuav ua rau lub siab evaporator siab, qis superheat thiab ua tau compressor dej nyab vim oversupply ntawm lub evaporator.Subcooling tuaj yeem poob rau hauv lub condenser ua rau lub taub hau qis thiab txawm tias poob ntawm cov kua foob rau hauv qab ntawm lub condenser.Lub taub hau qis thiab siab dua li qub evaporator siab yuav txo qis qhov sib piv ntawm compressor uas ua rau muaj kev ua haujlwm siab volumetric.Qhov no yuav ua rau kom lub peev xwm ntawm lub compressor, uas tuaj yeem sib npaug yog tias lub compressor tuaj yeem tswj cov tub yees siab hauv cov evaporator.Nws feem ntau tshwm sim tias cov tub yees overflows lub compressor, ua rau lub compressor tsis ua hauj lwm.
Rau cov laj thawj uas tau teev tseg saum toj no, nws yog ib qho tseem ceeb uas cov tshuab capillary muaj qhov tseeb (tseem ceeb) cov tub yees hauv lawv lub cev.Cov tub yees ntau dhau los yog tsawg dhau tuaj yeem ua rau muaj kev tsis sib haum xeeb thiab kev puas tsuaj loj rau lub compressor vim cov kua dej los yog dej nyab.Rau qhov zoo ntawm capillary sizing, sab laj cov chaw tsim khoom lossis xa mus rau cov chaw tsim khoom daim ntawv loj.Lub system daim ntawv teev npe lossis daim ntawv teev npe yuav qhia meej npaum li cas cov tub yees qhov system xav tau, feem ntau yog kaum lossis txawm pua ​​pua ntawm ib ooj.
Ntawm cov evaporator siab loads, capillary systems feem ntau ua hauj lwm nrog high superheat;Qhov tseeb, ib qho evaporator superheat ntawm 40 ° lossis 50 ° F tsis yog qhov tsis tshua muaj tshwm sim ntawm cov evaporator siab loads.Qhov no yog vim hais tias cov tub yees nyob rau hauv lub evaporator evaporates sai sai thiab nce 100% vapor saturation point nyob rau hauv lub evaporator, muab lub kaw lus siab superheat nyeem.Capillary raj tsuas yog tsis muaj lub tswv yim tawm tswv yim, xws li lub teeb pom kev zoo thermal expansion valve (TRV) cov chaw taws teeb, qhia rau lub ntsuas ntsuas tias nws ua haujlwm ntawm lub siab superheat thiab yuav kho nws.Yog li ntawd, thaum lub evaporator load yog siab thiab lub evaporator superheat yog siab, lub kaw lus yuav ua hauj lwm heev inefficient.
Qhov no tuaj yeem yog ib qho ntawm qhov tsis zoo ntawm cov kab mob capillary.Ntau tus kws tshaj lij xav ntxiv cov tub yees ntxiv rau lub kaw lus vim kev nyeem ntawv siab superheat, tab sis qhov no tsuas yog overload lub system.Ua ntej ntxiv cov tub yees, tshawb xyuas qhov kev nyeem ntawv superheat ntawm cov evaporator qis qis.Thaum qhov kub thiab txias hauv qhov chaw txias txias tau txo qis rau qhov xav tau kub thiab cov evaporator nyob rau hauv qis qis, cov evaporator superheat feem ntau yog 5 ° txog 10 ° F.Thaum muaj kev tsis ntseeg, sau cov tub yees, ntws lub kaw lus thiab ntxiv cov nqi hluav taws xob tseem ceeb uas tau teev tseg rau ntawm daim ntawv teev npe.
Thaum cov evaporator siab load txo qis thiab lub kaw lus hloov mus rau qis evaporator thaum tshav kub kub load, evaporator vapor 100% saturation point yuav txo qis dua ob peb dhau los ntawm cov evaporator.Qhov no yog vim qhov txo qis hauv evaporation tus nqi ntawm cov tub yees hauv cov evaporator vim muaj cua sov tsawg.Tam sim no lub kaw lus yuav muaj ib txwm evaporator superheat ntawm kwv yees li 5 ° txog 10 ° F.Cov evaporator ib txwm nyeem ntawv superheat tsuas yog tshwm sim thaum lub evaporator cua sov load tsawg.
Yog hais tias lub capillary system yog overfilled, nws yuav sau ntau tshaj cov kua nyob rau hauv lub condenser, ua rau lub taub hau siab vim tsis muaj ib tug receiver nyob rau hauv lub system.Lub siab poob nruab nrab ntawm qhov qis thiab siab siab sab ntawm lub system yuav nce, ua rau tus nqi ntws mus rau lub evaporator nce thiab cov evaporator yuav dhau mus, ua rau qis superheat.Nws tuaj yeem ua rau dej nyab lossis txhaws lub compressor, uas yog lwm qhov laj thawj vim li cas capillary systems yuav tsum nruj me ntsis los yog raug them nrog tus nqi ntawm cov tub yees.
John Tomczyk is Professor Emeritus of HVACR at Ferris State University in Grand Rapids, Michigan and co-author of Refrigeration and Air Conditioning Technologies published by Cengage Learning. Contact him at tomczykjohn@gmail.com.
Cov Ntsiab Lus Txhawb Nqa yog ib ntu them nyiaj tshwj xeeb uas cov tuam txhab kev lag luam muab cov ntsiab lus zoo, tsis muaj kev ncaj ncees, tsis yog lag luam rau cov ntsiab lus txaus siab rau ACHR cov neeg mloog xov xwm.Tag nrho cov ntsiab lus txhawb nqa yog muab los ntawm cov tuam txhab tshaj tawm.Xav koom nrog peb cov ntsiab lus txhawb nqa?Hu rau koj tus neeg sawv cev hauv zos.
Ntawm Kev Thov Hauv qhov webinar no, peb yuav kawm txog qhov hloov tshiab tshiab rau R-290 ntuj refrigerant thiab nws yuav cuam tshuam li cas rau HVACR kev lag luam.
Thaum lub sij hawm webinar, koj yuav kawm paub yuav ua li cas ua tau zoo dhau txhua theem ntawm kev lag luam loj hlob.