Lub hauv paus ntsiab lus ntawm kev xaiv flowmeter:
Lub hauv paus ntsiab lus ntawm kev xaiv lub flowmeter yog thawj zaug kom muaj kev nkag siab tob txog cov qauv txheej txheem thiab cov yam ntxwv ntawm cov dej ntws ntawm ntau yam flowmeters, thiab tib lub sijhawm, xaiv raws li cov xwm txheej tshwj xeeb ntawm qhov chaw thiab ib puag ncig ib puag ncig. Economic yam tseem ceeb yuav tsum tau muab coj los rau hauv tus account. Feem ntau, koj yuav tsum xaiv los ntawm tsib yam hauv qab no:
① Kev ua tau zoo ntawm cov flowmeter;
② dej yam ntxwv;
③ Cov kev xav tau ntawm kev teeb tsa;
④ Ib puag ncig tej yam kev mob;
⑤ Tus nqi ntawm cov ntsuas dej ntws.
1. Kev ua tau zoo ntawm cov flowmeter
Qhov kev ua tau zoo ntawm cov flowmeter feem ntau suav nrog: ntsuas ntws (instantaneous flow) lossis tag nrho cov nyiaj tau los (nruab nrab ntws); qhov yuav tsum tau muaj tseeb; repeatability; linearity; flow range thiab ntau yam; poob siab; tso zis teeb liab yam ntxwv thiab flowmeter teb lub sij hawm Tos.
(1) Ntsuas ntws los yog tag nrho cov nyiaj
Muaj ob hom kev ntsuas ntws, uas yog tam sim no ntws thiab cumulative flow. Piv txwv li, cov roj crude nyob rau hauv lub raj xa dej ntawm lub chaw nres tsheb sub-transportation belongs rau lub chaw tswj xyuas los yog petrochemical pipeline rau kev nruam proportional ntau lawm los yog cov txheej txheem tswj cov txheej txheem ntau lawm, thiab lwm yam. Tag nrho cov nyiaj yuav tsum tau ntsuas, qee zaum ntxiv los ntawm cov instantaneous flow kev soj ntsuam. Hauv qee qhov chaw ua haujlwm, kev tswj dej ntws yuav tsum ntsuas tam sim ntawd. Yog li ntawd, kev xaiv yuav tsum tau ua raws li qhov xav tau ntawm kev ntsuas ntawm qhov chaw. Qee qhov flowmeters xws li qhov zoo hloov pauv flowmeters,turbine flowmeters, thiab lwm yam, lub hauv paus ntsiab lus ntawm kev ntsuas yog ncaj qha kom tau txais tag nrho cov nyiaj los ntawm kev suav cov tshuab suav lossis pulse zaus tso zis, uas muaj qhov tseeb siab thiab tsim nyog rau kev ntsuas tag nrho cov nyiaj, yog tias nruab nrog cov khoom siv hluav taws xob sib thooj Flow kuj tuaj yeem tso tawm. Electromagnetic flowmeters, ultrasonic flowmeters, thiab lwm yam. txiav txim siab tus nqi ntws los ntawm kev ntsuas qhov ntws ntawm cov kua dej, nrog cov lus teb ceev ceev, tsim nyog rau kev tswj cov txheej txheem, thiab tag nrho cov nyiaj kuj tuaj yeem tau txais nrog kev ua haujlwm ntau.
(2) Qhov tseeb
Qhov tseeb theem ntawm flowmeter yog teev nyob rau hauv ib tug tej yam flow range. Yog hais tias nws yog siv nyob rau hauv ib tug tej yam kev mob los yog nyob rau hauv ib tug kuj nqaim flow range, piv txwv li, nws tsuas yog hloov nyob rau hauv ib tug me me ntau yam, ces nws ntsuas qhov tseeb yuav raug txo. siab tshaj qhov teev qhov tseeb ntawm chav kawm. Yog hais tias lub turbine flowmeter yog siv los ntsuas cov roj hauv cov thoob thiab cov khoom xa tawm, thaum lub valve qhib tag nrho, tus nqi ntws yog qhov qub, thiab nws qhov tseeb yuav raug txhim kho los ntawm {{0}}.5 mus rau 0.25.
Nws yog siv rau kev lag luam kev lag luam, kev khaws cia thiab kev thauj mus los thiab cov khoom sib npaug. Yog tias qhov ntsuas qhov tseeb yuav tsum muaj siab, qhov ntev ntawm qhov ntsuas qhov tseeb yuav tsum tau txiav txim siab. Feem ntau, lub flowmeter yog siv nyob rau hauv cov ntaub ntawv saum toj no, thiab qhov tseeb theem yuav tsum yog 0.2. Hauv cov chaw ua haujlwm zoo li no, cov cuab yeej ntsuas ntsuas (xws li cov raj ntim ntim) feem ntau yog nruab rau ntawm qhov chaw los tshawb xyuas online ntawm cov flowmeters siv. Nyob rau hauv xyoo tas los no, vim muaj kev nce siab ntawm cov roj crude thiab cov kev xav tau siab ntawm ntau chav nyob rau kev ntsuas roj av, kev siv cov coefficient xa mus rau kev ntsuas roj crude tau npaj tseg, uas yog, ntxiv rau kev tshuaj xyuas lub sijhawm ntawm cov flowmeter txhua txhua rau. lub hlis, ob tog rau kev lag luam sib tham sib tham txhua 1 lub hlis lossis 2. Lub flowmeter raug txheeb xyuas txhua hli los txiav txim siab qhov sib npaug, thiab cov ntaub ntawv raug xam raws li cov ntaub ntawv ntsuas los ntawm cov flowmeter thiab cov flow coefficient ntawm flowmeter rau kev xa mus rau txhim kho qhov tseeb ntawm flowmeter, tseem hu ua xoom-yuam kev xa mus.
Qib raug feem ntau txiav txim siab raws li qhov tso cai yuam kev ntawm flowmeter. Nws tau muab rau hauv cov lus qhia flowmeter muab los ntawm txhua tus neeg tsim khoom. Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov seb qhov feem pua ntawm kev ua yuam kev yog hais txog cov txheeb ze yuam kev lossis kev hais yuam kev. Qhov txheeb ze yuam kev yog qhov feem pua ntawm qhov ntsuas tus nqi, feem ntau qhia tias "feem pua R". Kev siv yuam kev yog hais txog qhov txwv siab tshaj ntawm qhov ntsuas lossis qhov feem pua ntawm qhov ntau, feem ntau yog siv li "feem pua FS". Ntau cov chaw tsim khoom cov lus qhia tsis qhia qhov no. Piv txwv li, float flowmeters feem ntau siv cov ntaub ntawv yuam kev, thiab qee cov qauv ntawm electromagnetic flowmeters kuj siv qhov yuam kev.
Yoglub flowmeterTsis tsuas yog ntsuas tus nqi tag nrho, tab sis yog siv rau hauv kev tswj cov dej ntws, qhov tseeb ntawm qhov ntsuas ntsuas ntsuas yuav tsum tau txiav txim siab raws li kev tswj xyuas qhov tseeb ntawm tag nrho cov kab ke. Vim tias tag nrho cov kab ke tsis tsuas yog muaj qhov yuam kev ntawm kev khiav dej num, tab sis kuj suav nrog qhov yuam kev thiab ntau yam cuam tshuam ntawm cov teeb liab kis tau tus mob, tswj kev hloov kho, kev ua haujlwm thiab lwm yam. Piv txwv li, yog tias muaj qhov sib txawv ntawm hysteresis txog li 2 feem pua hauv kev khiav hauj lwm, nws yog qhov tsis txaus ntseeg thiab tsis tsim nyog los txiav txim siab qhov tseeb siab dhau (saum qib 0.5) rau cov ntsuas ntsuas siv. Raws li qhov ntsuas nws tus kheej muaj kev txhawj xeeb, qhov tseeb ntawm lub sensor thiab qhov ntsuas thib ob yuav tsum tau ua kom zoo sib xws. Piv txwv li, qhov tsim kev ua yuam kev ntawm qhov nruab nrab lub voj voog uas tsis muaj qhov tseeb calibration yog nyob nruab nrab ntawm ± 2.5 feem pua thiab ± 4 feem pua, nrog 0.2 feem pua A qhov ntsuas qhov sib txawv nrog qhov raug siab ntawm ~0.5 feem pua yog me ntsis tseem ceeb.
Lwm qhov teeb meem yog tias qhov tseeb qib tau teev tseg rau cov flowmeter hauv cov txheej txheem kev txheeb xyuas lossis cov chaw tsim khoom siv phau ntawv hais txog qhov kev tso cai yuam kev ntawm flowmeter. Txawm li cas los xij, vim muaj kev hloov pauv ntawm ib puag ncig ib puag ncig, cov dej ntws ntws thiab cov xwm txheej zoo thaum lub flowmeter yog siv rau hauv qhov chaw, qee qhov yuam kev ntxiv yuav tshwm sim. Yog li ntawd, lub flowmeter siv nyob rau hauv lub tshav pob yuav tsum yog ib tug ua ke ntawm kev tso cai yuam kev thiab ntxiv yuam kev ntawm lub ntsuas nws tus kheej. Qhov teeb meem no yuav tsum tau txiav txim siab tag nrho. Qee lub sij hawm qhov yuam kev nyob rau hauv qhov ntau ntawm kev siv ib puag ncig ntawm qhov chaw yuav dhau qhov kev tso cai yuam kev ntawm flowmeter.
(3) Repeatability
Repeatability yog txiav txim siab los ntawm lub hauv paus ntsiab lus ntawm flowmeter nws tus kheej thiab kev tsim khoom zoo. Nws yog ib qho tseem ceeb qhia txog kev siv lub flowmeter thiab yog ze ze rau qhov tseeb ntawm lub flowmeter. Feem ntau, nyob rau hauv kev ntsuas kev ua tau zoo nyob rau hauv cov ntaub ntawv pov thawj, tsis yog tsuas yog cov qib raug tau teev tseg rau lub flowmeter, tab sis kuj tau teev cov repeatability. /3-1/5.
Repeatability feem ntau txhais tau tias yog qhov sib xws ntawm ntau qhov kev ntsuas nyob rau tib qho kev taw qhia rau qee qhov nqi ntws hauv lub sijhawm luv luv raws li qhov xwm txheej ib puag ncig thiab qhov nruab nrab tsis hloov pauv. Txawm li cas los xij, hauv kev siv tswv yim, qhov rov ua dua ntawm cov flowmeter feem ntau cuam tshuam los ntawm kev hloov pauv hauv cov kua dej viscosity thiab qhov ntom ntom. Qee lub sij hawm cov kev hloov pauv ntawm cov kev txwv no tsis tau mus txog qib uas yuav tsum tau kho tshwj xeeb, uas tej zaum yuav yuam kev rau qhov tsis zoo repeatability ntawm flowmeter. . Raws li qhov xwm txheej no, lub flowmeter uas tsis nkag siab rau cov kev hloov pauv hauv qhov ntsuas no yuav tsum raug xaiv. Piv txwv li, rotameter tau yooj yim cuam tshuam los ntawm cov kua dej ntom ntom. Me-inch flowmeters tsis tsuas yog cuam tshuam los ntawm cov kua dej ntom ntom, tab sis kuj tseem cuam tshuam los ntawm cov kua dej viscosity; Yog hais tias lub turbine flowmeter yog siv nyob rau hauv ib tug high viscosity ntau yam, lub viscosity yog cuam tshuam; ib txhia twb tsis raug kho. Ua tiavultrasonic flowmeterraug cuam tshuam los ntawm cov kua dej kub thiab ntau dua. Cov nyhuv no yuav qhia tau ntau dua yog tias qhov tso zis ntawm flowmeter tsis yog linear.
(4) Linearity
Qhov tso zis ntawm flowmeter feem ntau muaj ob hom linear thiab nonlinear square cag. Feem ntau hais lus, qhov tsis raug ntawm cov flowmeter tsis tau teev tseg, tab sis suav nrog qhov yuam kev ntawm flowmeter. Rau ib tug flowmeter nrog ib tug dav dav txaus ntau yam, cov zis teeb liab yog pulsed thiab siv rau tag nrho cov tsub zuj zuj, linearity yog ib qho tseem ceeb kev qhia. Yog hais tias ib tug meter coefficient siv nyob rau hauv nws cov ndlwg ntau yam, thaum lub linearity tsis zoo, yuav txo tau qhov tseeb ntawm lub flowmeter. Piv txwv li, lub turbine flowmeter txais ib lub 'meter' coefficient nyob rau hauv qhov ntws ntawm 10: 1, thiab nws qhov tseeb yuav qis dua thaum cov linearity tsis zoo. Nrog rau kev tsim kho tshuab computer, nws cov dej ntws tuaj yeem muab faib ua ntu thiab haum los ntawm txoj kev square. Lub flow-meter coefficient nkhaus kho cov flowmeter, yog li txhim kho qhov tseeb ntawm flowmeter thiab txuas ntxiv qhov ntws ntau.
(5) Upper limit flow thiab flow range
Cov dej ntws sab saud kuj tseem hu ua qhov ntsuas puv puv lossis ntws ntawm cov flowmeter. Thaum peb xaiv txoj kab uas hla ntawm lub flowmeter, nws yuav tsum tau teeb tsa raws li qhov kev khiav dej num uas siv los ntawm cov kav dej yuav tsum tau kuaj thiab qhov siab thiab qis qis ntawm cov flowmeter xaiv. Nws tsis tuaj yeem tsuas yog sib phim raws li txoj kab uas hla ntawm cov kav dej.
Feem ntau hais lus, tus qauv tsim cov raj xa dej ntws tau txiav txim siab raws li kev lag luam ntws. Yog tias qhov kev xaiv tsawg dhau, txoj kab uas hla ntawm cov yeeb nkab yuav tuab, thiab kev nqis peev yuav loj; yog tias qhov kev xaiv siab dhau lawm, lub zog sib kis yuav loj thiab cov nqi khiav lag luam yuav nce ntxiv. Piv txwv li, kev lag luam ntws ntawm cov kua dej uas muaj viscosity tsawg xws li dej yog 1.5-3m / s, thiab cov kua viscosity siab yog 0 2-1m / s. Tus nqi ntws ntawm tus nqi siab ntawm cov dej ntws feem ntau yog nyob ze lossis siab dua qhov kev lag luam ntws ntawm cov kav dej. Yog li ntawd, thaum xaiv lub flowmeter, nws txoj kab uas hla yog tib yam li cov kav dej, thiab kev teeb tsa yooj yim dua. Yog tias lawv tsis zoo ib yam, yuav tsis muaj qhov sib txawv ntau dhau. Feem ntau, cov kev qhia tshwj xeeb ntawm lub zog sab sauv thiab sab qis tuaj yeem txuas tau los ntawm kev txo cov kav dej.
Nyob rau hauv kev xaiv ntawm flowmeters, yuav tsum tau them nyiaj mloog mus rau ntau hom flowmeters, uas lub sab sauv txwv txaus tus nqi los yog lub siab tshaj plaws flow rate yog txawv heev vim hais tias ntawm cov kev txwv ntawm kev ntsuas thiab cov qauv ntawm lawv cov flowmeters. Ua ib qho piv txwv ntawm cov kua flowmeter, tus nqi ntws ntawm lub siab txwv ntws feem ntau yog nruab nrab ntawm 0.5 thiab 1.5m / s rau iav ntab flowmeter, nruab nrab ntawm 2.5 thiab 3.5m / s rau qhov zoo hloov pauv flowmeter, thiab nruab nrab ntawm 5.5 thiab 3.5m / s rau vortex flowmeter. Nruab nrab ntawm 7.5m / s,electromagnetic flowmeteryog nruab nrab ntawm 1 thiab 7m / s, lossis txawm nyob nruab nrab ntawm 0.5 thiab 10m / s.
Cov kev txwv sab saud ntawm cov kua kuj yuav tsum tau xav txog tias qhov tshwm sim cavitation tsis tuaj yeem tsim tawm vim tias qhov ntws ntws siab dhau lawm. Qhov chaw ntawm qhov tshwm sim cavitation feem ntau yog txoj hauj lwm ntawm tus nqi ntws thiab qhov siab zoo li qub. Txhawm rau tiv thaiv kev tsim cov cavitation, nws yog ib qho tsim nyog yuav tsum tau tswj xyuas qhov rov qab siab ntawm flowmeter (flow).
Nws yuav tsum tau muab sau tseg hais tias lub sab sauv txwv ntawm lub flowmeter tsis tuaj yeem hloov pauv tom qab kev txiav txim, xws li kev hloov pauv zoo flowmeter lossis rotameter. Thaum qhov sib txawv siab flowmeter, xws li lub phaj orifice ntawm lub throttling ntaus ntawv, tau tsim thiab txiav txim siab, nws qhov qis qis qis tus nqi ntws tsis tuaj yeem hloov pauv, thiab qhov kev txwv siab tshaj qhov hloov pauv tuaj yeem hloov pauv los ntawm kev kho qhov sib txawv ntawm lub siab transmitter lossis hloov lub Differential siab transmitter. Piv txwv li, rau qee cov qauv ntawm electromagnetic flowmeters lossis ultrasonic flowmeters, qee cov neeg siv tuaj yeem rov pib dua qhov txwv ntawm qhov ntws los ntawm lawv tus kheej.
(6) Ntau yam degree
Qhov ntau yam degree yog qhov sib piv ntawm qhov qis qis qis qis thiab qis qis qis ntawm cov flowmeter. Qhov loj dua tus nqi, qhov dav ntawm qhov ntws. Linear meters muaj ntau yam, feem ntau 1:10. Qhov ntau ntawm nonlinear flowmeters tsuas yog 1: 3. Rau cov ntsuas ntsuas feem ntau siv rau kev tswj cov txheej txheem lossis kev saib xyuas kev hloov pauv nyiaj txiag, yog tias yuav tsum muaj ntau yam txaus, tsis txhob xaiv lub ntsuas ntsuas nrog qhov me me.
Tam sim no, txhawm rau txhawm rau txhawb qhov dav dav ntawm lawv cov flowmeters, qee cov tuam txhab tau nce tus nqi ntws ntawm cov kev txwv siab siab siab heev hauv phau ntawv qhia, piv txwv li, cov kua tau nce mus rau 7-10m / s (feem ntau yog 6m / s); cov roj tau nce mus rau 50- 75m / s (feem ntau 40 ~ 50) m / s); Qhov tseeb, xws li tus nqi ntws siab yog siv tsis tau. Qhov tseeb, tus yuam sij rau ntau yam yog kom muaj qhov qis qis qis qis kom tau raws li qhov xav tau kev ntsuas. Yog li ntawd, qhov dav-ntau flowmeter nrog qis qis qis qis qis yog qhov ua tau zoo dua.
(7) Kev poob siab
Kev poob siab feem ntau txhais tau hais tias qhov ntws sensor ua rau qhov tsis tuaj yeem poob siab uas txawv ntawm qhov ntws los ntawm cov khoom zoo li qub lossis nquag nrhiav pom tau teeb tsa hauv cov dej ntws los yog hloov pauv hauv cov kev taw qhia ntws, thiab nws cov nqi qee zaum tuaj yeem ncav cuag kaum tawm kilopascals. Yog li ntawd, lub flowmeter yuav tsum raug xaiv raws li qhov tso cai poob siab ntawm qhov txaus txaus txiav txim siab los ntawm kev siv lub peev xwm ntawm cov kav dej thiab qhov nkag siab ntawm lub flowmeter. Kev xaiv tsis raug yuav txwv cov kua dej ntws tawm thiab ua rau lub siab poob siab thiab cuam tshuam rau kev khiav dej num. Qee cov kua dej (siab vapor siab hydrocarbon kua) kuj tseem yuav tsum paub tias kev poob siab ntau dhau yuav ua rau cavitation thiab vaporization ntawm cov kua theem, txo qhov ntsuas qhov tseeb lossis tseem ua rau lub flowmeter puas. Piv txwv li, lub flowmeter rau kev xa dej nrog cov yeeb nkab txoj kab uas hla ntau dua 500mm yuav tsum xav txog cov nqi siv zog ntau ntxiv los ntawm kev poob zog ntau dhau los ntawm kev poob siab. Raws li cov ntaub ntawv tseem ceeb, tus nqi ntawm cov twj tso kua mis flowmeter nrog lub siab loj poob rau kev ntsuas feem ntau tshaj li tus nqi yuav khoom ntawm lub flowmeter nrog lub siab poob qis thiab tus nqi siab dua.
(8) Cov yam ntxwv tso zis tawm
Cov zis thiab tso saib ntim ntawm flowmeter tuaj yeem muab faib ua:
① Flow (ntim ntim lossis loj txaus); ② Tag nrho; ③ Tus nqi ntws nruab nrab; ④ Point flow rate. Qee qhov ntsuas ntsuas tso zis analog ntau (tam sim no lossis voltage), thaum lwm tus tso zis ntau npaum li cas. Analog tso zis feem ntau suav hais tias tsim nyog rau kev tswj cov txheej txheem, thiab yog qhov tsim nyog rau kev sib txuas nrog kev tswj lub voj voog xws li tswj li qub; pulse tso zis ntau haum rau tag nrho thiab high-accuracy flow ntsuas. Ntev-ntev teeb liab kis tau tus mob pulse tso zis muaj ntau dua kis tau tus mob dua analog tso zis. Hom thiab amplitude ntawm lub teeb liab tso zis yuav tsum muaj peev xwm hloov mus rau lwm yam khoom siv, xws li kev tswj interfaces, cov ntaub ntawv processors, lub tswb nrov, qhib kev tiv thaiv circuits thiab cov ntaub ntawv kis tau tus mob.
(9) Lub sijhawm teb
Thaum ua ntawv thov rau cov ntawv thov pulsating flow, yuav tsum tau them nyiaj mloog mus rau lub flowmeter cov lus teb rau cov kauj ruam hloov. Qee daim ntawv thov xav kom cov flowmeter tso zis ua raws li cov dej ntws, thaum lwm tus xav tau cov lus teb qeeb qeeb kom tau txais qhov nruab nrab sib xyaw. Cov lus teb tsis tu ncua feem ntau tau hais nyob rau hauv cov nqe lus ntawm lub sij hawm tsis tu ncua los yog cov lus teb frequencies, qhov qub los ntawm ob peb milliseconds mus rau ob peb vib nas this, thiab tom kawg hauv qab no ntau pua ntawm Hz. Kev siv cov cuab yeej tso saib tuaj yeem txuas ntxiv lub sijhawm teb. Nws yog feem ntau ntseeg tias qhov asymmetry ntawm cov lus teb dynamic ntawm lub flowmeter thaum qhov ntws nce lossis txo qis yuav ua rau kom nce qhov kev ntsuas qhov yuam kev.
2. Cov yam ntxwv ua kua dej
Hauv kev ntsuas ntsuas, ntau yam flowmeters yeej ib txwm cuam tshuam los ntawm ib lossis ob peb yam tsis muaj nyob hauv lub cev ntawm cov kua dej, yog li lub cev lub cev ntawm cov kua dej yuav cuam tshuam rau kev xaiv cov flowmeter. Yog li ntawd, xaiv txoj kev ntsuas thiab flowmeter yuav tsum tsis tsuas yog hloov mus rau cov khoom ntawm cov kua yuav tsum tau ntsuas, tab sis kuj xav txog qhov cuam tshuam ntawm kev hloov pauv ntawm lub cev ntawm cov kua dej ntawm lwm qhov kev ntsuas thaum lub sijhawm ntsuas. Piv txwv li, qhov tshwm sim ntawm qhov kub thiab txias hloov ntawm viscosity ntawm cov kua.
Cov yam ntxwv ntawm cov kua dej yog qhov ntom ntom, viscosity, vapor siab thiab lwm yam tsis muaj. Cov kev txwv no feem ntau tuaj yeem pom nyob rau hauv phau ntawv los ntsuas qhov kev hloov pauv ntawm ntau yam tsis muaj dej thiab xaiv cov flowmeters raws li kev siv. Tab sis kuj tseem muaj qee yam khoom uas nrhiav tsis tau. Xws li corrosion, scaling, plugging, theem hloov thiab miscible xeev.
(1) Qhov kub thiab txias ntawm cov kua dej
Ua tib zoo txheeb xyuas qhov ua haujlwm siab thiab kub ntawm cov kua hauv lub flowmeter, tshwj xeeb tshaj yog thaum ntsuas cov roj, qhov kub thiab txias hloov pauv ua rau kev hloov pauv ntau dhau, thiab cov kev ntsuas xaiv yuav raug hloov. Piv txwv li, thaum kub thiab siab cuam tshuam rau kev ua tau zoo xws li kev ntsuas qhov tseeb, qhov kub thiab txias yuav tsum tau kho. Tsis tas li ntawd, cov qauv tsim lub zog tsim thiab cov khoom siv ntawm lub tsev flowmeter kuj nyob ntawm qhov kub thiab txias ntawm cov kua dej. Yog li ntawd, qhov tseem ceeb thiab qhov tseem ceeb ntawm qhov kub thiab txias yuav tsum paub meej. Ua tib zoo xaiv yuav tsum tau ua thaum kub thiab siab hloov pauv tau zoo heev.
Nws tseem yuav tsum tau muab sau tseg tias thaum ntsuas cov pa roj, nws yog ib qho tsim nyog yuav tsum paub meej tias nws qhov ntim ntws tus nqi yog qhov ntsuas kub thiab siab nyob rau hauv kev ua haujlwm lossis qhov kub thiab txias raws li lub xeev tus qauv.
(2) Qhov ntom ntawm cov kua dej
Rau cov kua, qhov ceev yog qhov tseem ceeb nyob rau hauv feem ntau cov ntawv thov, tshwj tsis yog muaj kev hloov loj loj, feem ntau tsis muaj qhov kho kom qis dua yuav tsum muaj. Hauv kev siv roj, qhov ntau thiab qhov sib txawv ntawm cov flowmeter nyob ntawm seb cov roj ntom ntom. Feem ntau, nws yog ib qho tsim nyog yuav tsum paub txog qhov tseem ceeb raws li cov txheej txheem thiab kev ua haujlwm rau kev xaiv. Kuj tseem muaj kev hloov pauv ntawm tus nqi ntawm lub xeev ntws mus rau qee qhov kev lees paub siv tus nqi, uas yog siv dav hauv roj av cia thiab kev thauj mus los. Tsawg-density gases tuaj yeem nyuaj rau qee txoj kev ntsuas, tshwj xeeb tshaj yog cov twj paj nruag uas siv lub zog ntawm cov pa los thawb lub sensor (xws li turbine flow meters).
(3) viscosity
Lub viscosity ntawm ntau cov kua sib txawv thiab txawv txav nrog qhov kub thiab txias. Cov roj sib txawv, qhov viscosity sib txawv ntawm ntau yam gases me me, thiab nws cov nqi feem ntau qis dua. Thiab yuav tsis hloov pauv vim qhov kub thiab txias hloov pauv. Vim lub viscosity ntawm cov kua yog ntau dua li cov roj. Piv txwv li, ntawm 20 degree thiab 100kPa, dynamic viscosity ntawm cov dej yog Pa·s, thaum lub dynamic viscosity ntawm huab cua yog Pa·s, yog li ntawd lub viscosity ntawm cov dej yuav tsum tau txiav txim siab rau cov kua, thaum lub viscosity ntawm gases tsis tseem ceeb li. ua kua.
Kev cuam tshuam ntawm viscosity ntawm ntau hom flowmeters txawv. Piv txwv li, tus nqi ntws ntawm electromagnetic flowmeters, ultrasonic flowmeters thiab Coriolis huab hwm coj flowmeters yog nyob rau hauv ntau yam viscosity, uas tuaj yeem suav tias tsis cuam tshuam los ntawm cov kua viscosity. ; Cov yam ntxwv yuam kev ntawm qhov zoo hloov pauv flowmeters muaj feem xyuam rau viscosity thiab tej zaum yuav cuam tshuam me ntsis; thaum lub rotameters, turbine flowmeters thiab vortex flowmeters muaj kev cuam tshuam ntau dua thaum lub viscosity ntau tshaj ib qho nqi thiab siv tsis tau.
Cov yam ntxwv ntawm qee qhov flowmeters tau piav qhia los ntawm cov yeeb nkab Reynolds tus lej raws li qhov ntsuas, thiab cov yeeb nkab Reynolds tus lej yog qhov ua haujlwm ntawm cov kua dej viscosity, ntom, thiab cov yeeb nkab tshaj tawm. Yog li ntawd, viscosity tseem muaj feem cuam tshuam rau cov yam ntxwv ntawm qhov ntsuas.
Viscosity kuj yog ib qho kev ntsuas kom paub qhov txawv ntawm Newtonian los yog non-Newtonian kua, thiab feem ntau cov kev ntsuas ntws thiab flowmeters tsuas yog haum rau Newtonian kua. Tag nrho cov pa roj yog cov kua Newtonian. Cov kua dej feem ntau, nrog rau cov kua dej uas muaj qee qhov me me ntawm cov thooj kheej kheej, kuj yog cov kua Newtonian. Kev ntsuas cov qauv thiab cov flowmeters uas tsuas yog siv tau rau Newtonian kua yuav cuam tshuam rau kev ntsuas thaum siv rau cov kua dej uas tsis yog Newtonian. Yog li ntawd, Newtonian kua yog ib qho tseem ceeb rau kev siv ntawm cov kua ntws ntsuas.
Kev cuam tshuam ntawm viscosity ntawm qhov sib txawv ntawm ntau hom flowmeters txawv. Feem ntau, qhov viscosity ntawm qhov zoo hloov pauv flowmeters nce thiab ntau qhov nthuav dav. Lub turbine flowmeter thiab vortex flowmeter yog qhov sib txawv, qhov viscosity nce thiab qhov ntau tsawg. Yog li ntawd, cov yam ntxwv kub-viscosity ntawm cov kua yuav tsum tau tuav thaum ntsuas qhov tsim nyog ntawm cov kua.flowmeter.
Qee cov kua dej uas tsis yog Newtonian (xws li cov av nkos, cov ntaub so ntswg, qhob noom xim kasfes, thiab xim) muaj cov dej ntws nyuaj, thiab nws nyuaj rau txiav txim siab lawv cov khoom. Yuav tsum tau saib xyuas thaum xaiv lub flowmeter.
(4) Tshuaj corrosion thiab scaling
① Cov teeb meem tshuaj corrosion
Qhov teeb meem ntawm cov tshuaj corrosion ntawm cov kua dej qee zaum yog qhov kev txiav txim siab hauv peb txoj kev xaiv kev ntsuas thiab kev siv cov ntsuas ntsuas. Piv txwv li, qee cov kua dej yuav corrode qhov sib cuag ntawm lub flowmeter, fouling lossis depositing crystals rau saum npoo, thiab electrolytic chemistry rau saum npoo ntawm cov hlau, uas yuav txo tau qhov kev ua tau zoo thiab kev pab cuam lub neej ntawm flowmeter. Yog li ntawd, txhawm rau daws qhov teeb meem ntawm cov tshuaj corrosion thiab scaling, manufacturers tau siv ntau txoj hauv kev, xws li xaiv cov khoom siv los tiv thaiv corrosion los yog noj cov tshuaj tiv thaiv corrosion ntawm cov qauv ntawm cov flowmeter, piv txwv li, lub orifice phaj ntawm lub throttling ntaus ntawv. yog ua los ntawm cov ntaub ntawv ceramic, thiab tus nqi ntws ntawm cov hlau ntab yog Qhov ntsuas yog lined nrog corrosion-resistant engineering plastics. Txawm li cas los xij, rau cov flowmeters nrog ntau cov qauv, xws li qhov zoo ntawm kev hloov pauv flowmeters thiab turbine flowmeters, nws tsis tuaj yeem ntsuas cov kua dej corrosive. Qee cov flowmeters muaj kev tiv thaiv corrosion los yog yooj yim rau kev ntsuas corrosion los ntawm cov qauv qauv. Lub transducer sojntsuam ntawm ultrasonic flowmeter yog ntsia rau sab nrauv phab ntsa ntawm cov kav dej thiab tsis nyob rau hauv kev sib cuag nrog cov kua ntsuas, uas yog qhov tseem ceeb los tiv thaiv corrosion. Lub tshuab electromagnetic flowmeter tsuas yog ntsuas lub raj hauv ob sab phlu thiab ib khub ntawm cov electrodes uas muaj cov duab yooj yim hauv kev sib cuag nrog cov kua. Nyob rau hauv xyoo tas los no, qee cov qauv tsim tsis tiv thaiv cov electrodes nrog cov kua, uas kuj yog ib qho kev tiv thaiv corrosion.
② Scaling
Raws li kev ntsuas los yog crystallization ntawm lub flowmeter kab noj hniav thiab ntws sensor, lub clearance ntawm txav qhov chaw nyob rau hauv lub flowmeter yuav raug txo, thiab rhiab heev los yog ntsuas kev ua tau zoo ntawm lub rhiab ntsiab nyob rau hauv lub flowmeter yuav raug txo. Piv txwv li, ntawm daim ntawv thov ultrasonic flowmeter, txheej fouling tuaj yeem cuam tshuam ultrasonic emission. Nyob rau hauv daim ntawv thov electromagnetic flowmeter, ib txheej uas tsis yog-conductive scaling insulates lub electrode nto thiab ua rau cov flowmeter inoperable. Yog li ntawd, qee qhov flowmeters feem ntau siv cov cua sov sab nraud ntawm qhov ntws sensor los tiv thaiv nag lossis daus ntawm crystallization lossis nruab ib lub tshuab descaling.
Qhov tshwm sim ntawm cov tshuaj corrosion thiab scaling yog hloov qhov roughness ntawm sab hauv phab ntsa ntawm cov yeeb nkab kuaj, thiab qhov roughness yuav cuam tshuam rau qhov ntws ntawm cov kua dej. Yog li ntawd, nws raug pom zoo tias cov neeg siv yuav tsum tau xyuam xim rau qhov teeb meem no. Piv txwv li, cov kav dej uas tau siv ntau xyoo yuav tsum tau ntxuav thiab descaled.
Corrosion thiab fouling cuam tshuam cov kev ntsuas ntsuas kev hloov pauv uas txawv ntawm hom flowmeter. Cov nram qab no yuav siv ultrasonic flowmeter thiab electromagnetic flowmeter ua piv txwv los piav qhia cov txiaj ntsig vim qhov cuam tshuam ntawm cov kav dej scaling. Piv txwv li, rau lub raj xa dej nrog ib txoj kab uas hla ntawm 50mm, sab hauv phab ntsa scaling los yog deposition ntawm 0.1-0.2 hli yuav txo qhov cheeb tsam ntawm lub ntsuas pipeline los ntawm {{ 8}}.4 feem pua -0.6 feem pua , qhov ua yuam kev tshwm sim yuav yog qhov sib txawv uas tsis tuaj yeem tsis quav ntsej rau cov flowmeter ntawm chav kawm 0.5 rau 1.0.
(5) Compression yam
Cov roj compression coefficient z yog qhov sib piv ntawm qhov tseeb ntim rau "ntim" ntawm ib qho loj ntawm cov roj ntawm tib qhov kub thiab siab. Feem ntau, rau gas z=0; qhov tseeb roj z yuav ntau dua 1 lossis tsawg dua 1. Qhov loj ntawm qhov sib txawv ntawm z los ntawm 1 qhia qhov degree uas cov pa tiag deviates los ntawm cov pa. Cov roj compressibility z tus nqi nyob ntawm hom lossis muaj pes tsawg leeg, kub, siab. Yog li ntawd, kev ntsuas roj yuav tsum tau txais cov kua dej ntom ntom hauv lub xeev ua haujlwm los ntawm kev sib xyaw ua ke. Qhov ceev yog xam los ntawm qhov kub, siab thiab compressibility rau cov kua nrog cov khoom ruaj khov. Yog tias cov kua dej muaj ntau yam (xws li kev ntsuas ntawm cov pa roj carbon monoxide) thiab ua haujlwm ze (lossis hauv) thaj tsam supercritical, yuav tsum ntsuas qhov ceev hauv online los ntsuas qhov ceev hauv online.
3. Kev teeb tsa ntawm flowmeter
1. Cov teeb meem xav tau kev saib xyuas thaum lub sijhawm teeb tsa
Cov teeb meem kev teeb tsa muaj cov kev cai sib txawv rau cov ntsuas ntws ntawm cov qauv sib txawv. Rau qee qhov flowmeters, xws li qhov sib txawv siab flowmeters thiab tshaj tawm flowmeters, raws li cov cai, qee qhov ntev lossis cov kav dej ncaj ncaj yuav tsum tau nruab rau sab saud thiab qis qis ntawm cov flowmeter kom ntseeg tau tias cov dej ntws ua ntej qhov kawg ntawm lub flowmeter yog tag nrho. tsim tawm. . Thaum lwm cov flowmeters, xws li qhov zoo hloov pauv flowmeters, ntab flowmeters, thiab lwm yam, tsis muaj lossis qis dua ntawm qhov ntev ntawm cov yeeb nkab ncaj.
Qee qhov flowmeters muaj qee qhov yuam kev vim muaj kev cuam tshuam ntawm kev teeb tsa. Piv txwv li, Coriolis huab hwm coj flowmeters yuav coj qhov yuam kev zoo los siv vim muaj kev cuam tshuam ntawm kev teeb tsa kev ntxhov siab. Cov teeb meem ntawm kev siv cov flowmeters rov qab yuav tsis tas yog vim muaj teeb meem ntawm lub flowmeter nws tus kheej, thiab ntau qhov xwm txheej yog tshwm sim los ntawm kev teeb tsa tsis zoo. Cov teeb meem tshwm sim yog raws li nram no:
① Rov qab qhov chaw nkag ntawm lub qhov rooj ntawm qhov sib txawv siab flowmeter;
② Lub ntsuas dej ntws tau nruab rau hauv qhov chaw uas muaj qhov tsis zoo ntws nrawm nrawm;
③ Cov theem tsis xav tau muaj nyob rau hauv cov yeeb nkab impulse txuas nrog cov cuab yeej sib txawv;
④ Lub flowmeter tau nruab rau hauv qhov chaw tsis zoo lossis hauv qhov chaw nkag tsis tau;
⑤ Cov kev taw qhia ntws ntawm lub flowmeter raug teeb tsa tsis raug;
⑥ Lub flowmeter los yog hluav taws xob teeb liab kis tau tus mob yog muab tso rau hauv ib tug muaj zog electromagnetic teb;
⑦ Nruab lub flowmeter cuam tshuam rau kev cuam tshuam ntawm lub raj xa dej nrog kev co;
⑧ Tsis muaj cov khoom siv tiv thaiv tsim nyog.
2. Kev teeb tsa kev teeb tsa
Thaum siv lub flowmeter, yuav tsum tau them nyiaj mloog mus rau lub adaptability thiab yuav tsum tau ntawm installation tej yam kev mob, feem ntau yog los ntawm cov nram qab no yam, xws li cov kev taw qhia ntawm lub installation ntawm lub flowmeter, ntws cov kev taw qhia ntawm cov kua, configuration ntawm upstream thiab downstream pipelines, valve. txoj hauj lwm, tiv thaiv accessories, pulsating flow influence, vibration, hluav taws xob cuam tshuam thiab kev saib xyuas ntawm flowmeters, thiab lwm yam.
① Cov kav dej ntawm qhov chaw
Ua tib zoo saib xyuas cov kev taw qhia kev teeb tsa ntawm lub flowmeter thaum txuas cov kav dej ntawm qhov chaw. Txij li thaum cov kev taw qhia kev teeb tsa ntawm lub flowmeter feem ntau muab faib rau hauv txoj kev teeb tsa ntsug thiab kab rov tav txoj kev teeb tsa, muaj qhov sib txawv ntawm qhov ntsuas kev ua tau zoo rau ob txoj kev teeb tsa no. Piv txwv li, txoj kab nqes qis qis ntawm cov kua dej yuav ua rau muaj zog ntxiv rau lub flowmeter sensor, uas yuav cuam tshuam rau kev ua haujlwm ntawm flowmeter, thiab txo cov linearity thiab repeatability ntawm flowmeter. Cov kev taw qhia kev teeb tsa ntawm lub flowmeter kuj nyob ntawm lub cev lub cev ntawm cov kua dej. Piv txwv li, cov kav dej kab rov tav yuav precipitate cov khoom, yog li lub flowmeter ntsuas lub xeev no yog ntsia rau hauv txoj kab ntsug.
② Flow kev taw qhia ntawm cov kua
Qhov teeb meem no zoo ib yam li cov kev taw qhia installation ntawm flowmeter. Txij li qee qhov flowmeters tsuas tuaj yeem ua haujlwm hauv ib qho kev taw qhia, thim rov qab yuav ua rau lub flowmeter puas. Kev siv cov flowmeters zoo sib xws kuj tseem txiav txim siab qhov muaj peev xwm rov qab ntws hauv qhov xwm txheej tsis ua haujlwm, uas yuav tsum muaj kev ntsuas xws li kev txhim kho cov tshev valve los tiv thaiv cov flowmeter. Txawm tias lub flowmeter uas tuaj yeem siv tau rau ob qho kev qhia yuav muaj qee qhov sib txawv hauv kev ntsuas kev ua tau zoo ntawm kev rau pem hauv ntej thiab rov qab, thiab yuav tsum tau siv raws li cov chaw tsim khoom tau teev tseg.
③ Cov kav dej ntws thiab cov dej ntws ncaj nraim ntawm cov flowmeter
Txij li thaum lub flowmeter yuav raug cuam tshuam los ntawm lub xeev ntws ntawm lub raj xa dej inlet, cov kav dej fittings tseem yuav qhia txog kev cuam tshuam ntawm kev ntws. Lub ndlwg cuam tshuam feem ntau suav nrog vortex thiab ntws nrawm faib profile distortion. Lub hav zoov ntawm vortex feem ntau yog vim muaj ob lossis ntau qhov chaw (lub tso suab) lub luj tshib los ntawm. Distortion ntawm qhov nrawm profile feem ntau yog tshwm sim los ntawm kev cuam tshuam hauv zos hauv cov yeeb nkab fittings (xws li li qub) lossis lub luj tshib. Cov teebmeem no yuav tsum tau ua kom zoo dua nrog kev ncaj nraim ntawm qhov ntev uas tsim nyog lossis kev teeb tsa ntawm cov cua txias. Ntxiv nrog rau kev xav txog kev cuam tshuam ntawm cov flowmeter kev sib txuas fittings, koj tuaj yeem xav txog kev cuam tshuam ntawm kev sib txuas ntawm cov kav dej ntws tawm, vim tias lawv tuaj yeem tsim cov kev cuam tshuam sib txawv, yog li nco ntsoov khaws qhov kev ncua deb ntawm qhov chaw cuam tshuam kom deb li deb tau. txo lawv lub hwj chim. Piv txwv li, ib feem qhib valve ua raws tam sim ntawd tom qab ib qho khoov.
Ib qho ncaj yeeb nkab seem tseem yuav tsum tau downstream ntawm flowmeter kom txo qis cov dej ntws los.
Rau volumetric flowmeters thiab Coriolis huab hwm coj flowmeters, lawv tsis cuam tshuam los ntawm asymmetric flow profiles; turbine flowmeters yuav tsum tau siv los txo cov vortex; electromagnetic flowmeters thiab qhov sib txawv siab flowmeters yuav tsum txwv lub vortex mus rau ib qho me me hauv qhov ntau.
Cavitation thiab condensation yog tshwm sim los ntawm cov yeeb nkab tsis tsim nyog, tsis txhob hloov pauv ntawm cov yeeb nkab txoj kab uas hla thiab kev taw qhia. Tsis zoo piping layout tuaj yeem tsim pulsation.
④ Txoj kab uas hla thiab cov yeeb nkab vibration
Qee hom flowmeters tsis muaj ntau yam ntawm cov yeeb nkab diameters, yog li loj lossis me dhau yuav txwv cov kev xaiv ntawm ntau hom flowmeter. Txhawm rau ntsuas qhov ntws ntawm tus nqi qis lossis siab txaus, koj tuaj yeem xaiv lub flowmeter nrog ib txoj kab sib txawv ntawm cov yeeb nkab txoj kab uas hla, thiab koj tuaj yeem siv lub reducer los txuas ua kom lub flowmeter khiav hauv qhov kev teev tseg. Yog tias tus nqi ntws dhau qhov ntau, yog tias tus nqi ntws qis dhau lawm, qhov yuam kev ntawm lub flowmeter yuav nce, thiab qhov yuam kev flowmeter yuav nce.
Qee cov flowmeters, xws li vortex flowmeters thiab Coriolis huab hwm coj flowmeters ntawm piezoelectric detectors, yog rhiab heev rau txhua yam kev vibrations thiab yooj yim cuam tshuam los ntawm pipeline vibrations. Kev saib xyuas yuav tsum tau them rau qhov tsim ntawm kev txhawb nqa ntawm cov kav dej ua ntej thiab tom qab lub flowmeter. Ntxiv nrog rau kev siv cov tshuaj tua kab mob txhawm rau tshem tawm cov teebmeem ntawm kev ua pa, kev saib xyuas kuj tseem yuav tsum tau them nyiaj rau khaws tag nrho cov ntsuas ntws tawm kom deb ntawm qhov chaw ntawm kev co lossis kev ua pa.
⑤ Txhim kho txoj haujlwm ntawm lub valve
Cov tswj valve thiab kev sib cais valve yog ntsia rau hauv cov kav dej uas qhov ntsuas ntsuas tau nruab. Txhawm rau kom tsis txhob muaj qee qhov kev cuam tshuam ntawm kev xa tawm kev cuam tshuam thiab cavitation tshwm sim los ntawm lub valve thiab cuam tshuam rau kev ntsuas flowmeter, lub valve tswj dav dav yuav tsum tau nruab rau hauv qab ntawm lub flowmeter, thiab cov tswj valve yuav tsum tau muab tso rau hauv lub flowmeter. Lub siab rov qab ntawm lub flowmeter tuaj yeem ua rau qis qis kom txo tau cov cavitation hauv cov flowmeter.
Lub hom phiaj ntawm kev rho tawm valve yog cais cov flowmeter los ntawm cov kua hauv kab kom yooj yim txij nkawm. Lub valve upstream yuav tsum nyob deb txaus ntawm lub flowmeter. Thaum lub flowmeter khiav, lub upstream valve yuav tsum tau qhib tag nrho kom tsis txhob muaj kev cuam tshuam xws li kev faib tawm tus nqi distortion.
⑥ Cov khoom siv tiv thaiv
Kev txhim kho cov khoom siv tiv thaiv yog kev tiv thaiv kev ntsuas kom ntseeg tau tias kev ua haujlwm zoo ntawm cov flowmeter. Piv txwv li, nyob rau hauv zoo xaav flowmeters thiabturbine flowmeters, qee yam khoom siv tsim nyog xws li cov ntxaij lim dej feem ntau yuav tsum tau muab tso rau saum toj. Tag nrho cov khoom siv no yuav tsum tau teeb tsa kom tsis txhob cuam tshuam kev siv cov flowmeter.
⑦ Kev sib txuas hluav taws xob thiab hluav taws xob cuam tshuam
Tam sim no, feem ntau cov kev ntsuas dej ntws, txawm tias nws yog lub flowmeter nws tus kheej lossis nws cov khoom siv, muaj cov khoom siv hluav taws xob, yog li cov khoom siv hluav taws xob siv yuav tsum sib phim nrog cov flowmeter. Thaum cov zis theem ntawm cov flowmeter tsawg, lub preamplifier haum rau ib puag ncig yuav tsum tau siv. Lub teeb liab tso zis ntawm qee hom flowmeters tau yooj yim cuam tshuam los ntawm cov khoom siv hluav taws xob hloov hluav taws xob, uas ua rau cov zis pulses ntawm flowmeter fluctuate thiab cuam tshuam rau kev ua haujlwm ntawm flowmeter. Piv txwv li, lub teeb liab cable yuav tsum nyob deb ntawm lub hwj chim cable thiab lub zog hluav taws xob li sai tau kom txo tau electromagnetic cuam tshuam thiab xov tooj cua zaus cuam tshuam. cuam tshuam.
⑧ Pulsating ntws thiab tsis khov kho
Ntxiv nrog rau kev siv cov tshuaj tua kab mob pulsation, kev saib xyuas yuav tsum tau them rau khaws tag nrho cov ntsuas ntws tawm kom deb ntawm qhov chaw pulsation. Feem ntau qhov chaw ntawm pulsation muaj xws li cov twj tso kua mis, cov twj tso kua mis reciprocating, oscillating li qub lossis cov tswj hwm, cov tsheb ciav hlau vortex thiab lwm yam hydraulic oscillations. Feem ntau, qhov sib txawv siab flowmeters muaj pulsating flow yuam kev, thiab turbine flowmeters thiabvortex flowmeterskuj muaj pulsating flow yuam kev. Unsteady flow yog ib qho dej ntws uas sib txawv nrog lub sijhawm thiab qeeb pulsation yog qhov tshwj xeeb ntawm cov dej tsis khov. Xws li qeeb pulsations tshwm sim los ntawm kev ua haujlwm ntawm kev tswj hwm lub valve.
Flow meter tuaj yeem tswj tau qhov cuam tshuam ntawm lub zog ntawm qhov ntws sensor thiab cov khoom siv thib ob cais. Nruab lub ntsuas dej ntws tawm ntawm qhov chaw ntawm lub tshuab nqus dej, lossis nruab ib lub lim dej qis xws li snubber (rau cov kua) lossis choke (rau roj) hauv cov kav dej kom txo tau cov qib ntawm pulsation. Cov khoom siv thib ob tuaj yeem xaiv lub flowmeter nrog cov lus teb zoo (xws li electromagnetic flowmeter, ultrasonic flowmeter) kom ua kom lub damping, thiab ntsuas qhov ntsuas pulsation los kwv yees qhov yuam kev ntxiv ntawm lub pulsation.
4. Ib puag ncig kev xav tau
Nyob rau hauv tus txheej txheem ntawm kev xaiv flowmeters, ib puag ncig tej yam kev mob thiab lwm yam kev hloov, xws li ambient kub, av noo, kev nyab xeeb thiab hluav taws xob cuam tshuam, yuav tsum tsis txhob ignored.
① Ambient kub
Ambient kub hloov tuaj yeem cuam tshuam rau qhov hluav taws xob ntawm cov flowmeter thiab qhov ntws sensor. Piv txwv li, kev hloov pauv kub tuaj yeem cuam tshuam cov kev hloov pauv ntawm qhov ntsuas qhov loj me, hloov hluav taws xob los ntawm lub tsev ntsuas dej ntws, kev hloov pauv hauv cov kua dej ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom, thiab lwm yam. Lub ntsuas dej ntws thiab cov ntsuas ntsuas thib ob yuav tsum tau muab tso rau hauv ntau qhov chaw, xws li cov khoom siv thib ob yuav tsum tau muab tso rau hauv chav tswj xyuas kom ntseeg tau tias cov khoom siv hluav taws xob tsis cuam tshuam los ntawm qhov kub thiab txias. Nws yuav tsum tau hais tias qhov cuam tshuam ntawm ambient kub yuav tsum tsis txhob yog ib qho ntawm cov kev cuam tshuam tseem ceeb ntawm kev tsis paub tseeb thaum kwv yees tag nrho qhov tsis paub tseeb ntawm kev ntsuas ntws.
② Ambient humidity
Atmospheric humidity nyob rau hauv ib puag ncig kuj yog ib qho teeb meem cuam tshuam rau kev siv cov flowmeter. Piv txwv li, high humidity yuav ceev atmospheric corrosion thiab electrolytic corrosion thiab txo cov hluav taws xob rwb thaiv tsev, thiab cov av noo tsawg yuav ua rau muaj hluav taws xob zoo li qub. Kev hloov pauv sai hauv qhov ntsuas kub nruab nrab lossis nruab nrab tuaj yeem ua rau muaj teeb meem av noo xws li condensation ntawm qhov chaw.
③ Kev ruaj ntseg
Lub flowmeter yuav tsum raug xaiv raws li cov kev qhia tshwj xeeb thiab cov qauv tsim nyog rau kev siv nyob rau hauv qhov chaw muaj kev phom sij tawg, thiab qhov chaw yuav tsum tau ua raws li cov qauv kev tawg.
④ Kev cuam tshuam hluav taws xob
Fais fab cables, motors, thiab hluav taws xob hloov hluav taws xob tag nrho ua rau muaj kev cuam tshuam electromagnetic, uas tuaj yeem ua yuam kev hauv kev ntsuas dej yog tias tsis muaj kev ntsuas.
5. Kev xav txog nyiaj txiag
1. Xav txog tus nqi ntawm kev yuav ib lub flowmeter los ntawm kev pom kev lag luam
Thaum muas ib lub flowmeter, kev lag luam cuam tshuam ntawm ntau hom flowmeters ntawm tag nrho cov kev ntsuas yuav tsum muab piv. Piv txwv li, ib tug flowmeter nrog ib tug me me tshaj li ib tug flowmeter nrog ib tug dav ntau yam yuav tsum tau them los ntawm ntau yam flowmeters nyob rau hauv parallel thiab ntau pipelines nyob rau hauv tib qhov kev ntsuas. Yog li ntawd, nyob rau hauv tas li ntawd mus rau lub flowmeter, muaj ntau yam khoom pab, xws li li qub thiab pipeline accessories, yuav tsum tau ntxiv. Tos. Txawm hais tias tus nqi ntawm cov ntsuas ntws tau txo qis rau ntawm qhov chaw, lwm cov nqi tau nce, uas tsis raug nqi rau kev suav. Piv txwv li, tus nqi ntawm kev txhim kho lub orifice flowmeter ntxiv rau qhov ntsuas qhov sib txawv ntawm qhov sib txawv yog qhov pheej yig, tab sis tus nqi ntawm kev tsim lub voj voog ntsuas, suav nrog cov khoom siv ruaj khov ntawm lub orifice phaj, tuaj yeem tshaj tus nqi ntawm cov khoom hauv paus.
2. Kev teeb tsa tus nqi
Thaum muas ib lub flowmeter, tsis yog tsuas yog tus nqi yuav khoom ntawm lub flowmeter, tab sis kuj muaj lwm cov nqi, xws li cov nqi yuav khoom, kev teeb tsa thiab commissioning tus nqi, kev saib xyuas thiab kev soj ntsuam tsis tu ncua, tus nqi khiav lag luam thiab cov nqi seem yuav tsum raug txiav txim siab.
Piv txwv li, ntauflow metersyuav tsum tau nruab nrog qhov ntev ntawm cov kav dej ncaj nraim kom ntseeg tau tias lawv ntsuas kev ua tau zoo. Kev txhim kho kom zoo yog li yuav tsum tau npaj cov kav dej ntxiv lossis hla cov kav dej rau kev saib xyuas tsis tu ncua. Yog li ntawd, tus nqi installation yuav tsum raug xam tias tsim nyog nyob rau hauv ntau yam, xws li nres valve, lim thiab lwm yam kev pabcuam uas yuav tsum tau ua rau kev ua haujlwm.
3. Cov nqi khiav haujlwm
Kev khiav hauj lwm tus nqi ntawm cov flowmeter feem ntau yog siv lub zog siv thaum lub sijhawm ua haujlwm, suav nrog kev siv hluav taws xob sab hauv ntawm lub ntsuas hluav taws xob lossis lub zog siv hluav taws xob ntawm lub tshuab hluav taws xob pneumatic thiab lub zog siv los thawb cov kua dej los ntawm cov cuab yeej thaum ntsuas kev ntsuas. , uas yog, lub twj tso kua mis uas overcomes lub siab poob los ntawm qhov ntsuas vim kev ntsuas. Shipping nqi thiab lwm yam Piv txwv li, ib tug loj ib feem ntawm qhov sib txawv siab generated los ntawm txawv siab flowmeters tsis tuaj yeem rov qab tau, thiab zoo displacement flowmeters thiab turbine flowmeters kuj muaj kev cuam tshuam loj heev. Tsuas yog puv-channel, tsis muaj kev cuam tshuamelectromagnetic flowmetersthiabultrasonic flowmetersYeej muaj pes tsawg tus nqi, thiab cov twj tso kua mis muaj qhov cuam tshuam me me rau cov yeeb nkab loj, thiab lawv qhov kev poob siab tuaj yeem tsis quav ntsej.
Nws yog kwv yees hais tias ib xyoos siv lub zog siv ntawm qhov sib txawv ntawm lub siab orifice flowmeter nrog txoj kab uas hla ntawm 100mm yog sib npaug rau tus nqi yuav khoom ntawm lub flowmeter. Yog tias hloov pauv electromagnetic flowmeter, tus nqi yuav khoom tsuas yog sib npaug li plaub xyoos. ntawm kev siv zog. Nws tau pom tias kev siv lub zog siv ntawm cov kav dej loj dua yuav kim dua. Nws yog feem ntau ntseeg hais tias lub flowmeter nrog lub siab poob qis thiab tsis muaj siab poob yuav tsum tau siv ntau li ntau tau rau lub flowmeter tshaj 5000mm. Piv txwv li, ib txwm muaj qhov sib txawv siab flowmeters siv hauv cov dej xa dej tsis tshua siv cov paib orifice thiab siv Venturi hlab nrog tsis tshua muaj siab. Tam sim no lawv tau hloov kho rau electromagnetic flowmeters thiab ultrasonic flowmeters.
4. Tus nqi kuaj
Tus nqi kuaj yuav tsum txiav txim siab raws li lub sijhawm pov thawj ntawm cov flowmeter. Rau kev tshawb pom cov roj av los yog cov roj refined feem ntau yog siv rau kev lag luam kev sib hais haum, ib qho qauv ntim raj feem ntau tau teeb tsa rau ntawm qhov chaw los ua qhov kev txheeb xyuas online ntawm flowmeter.
5. Cov nqi tu thiab cov nqi seem, thiab lwm yam.
Tus nqi txij nkawm yog tus nqi uas yuav tsum tau ua kom lub ntsuas ntsuas ua haujlwm ib txwm ua tom qab siv cov flowmeter, feem ntau suav nrog cov nqi tu thiab cov khoom seem. Flowmeters nrog cov khoom txav yuav tsum tau ua haujlwm ntau dua, xws li hloov pauv cov kabmob hnav-tiv taus, shafts, khiav, kis tau tus mob, thiab lwm yam; flowmeters tsis txav qhov chaw kuj yuav tsum tau kuaj xyuas, xws li cov qauv ntsuas geometric zoo tib yam los kuaj xyuas lub orifice phaj flowmeter.
Cov nqi khoom seem yuav nce ntxiv raws li qhov ua tau zoo ntawm cov flowmeter txhim kho. Thaum xaiv ib lub flowmeter, yuav tsum xav txog kom nce tus nqi ntawm cov khoom seem, tshwj xeeb tshaj yog cov flowmeter imported los ntawm txawv teb chaws, thiab qee zaum tag nrho cov flowmeter feem ntau yog hloov vim qhov nyuaj ntawm kev hnav cov khoom seem.
6. Kev xaiv cov kev ntsuas thiab cov flowmeters
Cov ntu yav dhau los yog tag nrho hais txog kev xaiv cov flowmeters dav dav. Tshooj lus no yuav siv cov kev xaiv ntawm flowmeters rau ntsuas slurry flow, cov kua dej loj thiab cov dej ntws ua piv txwv.
1. Kev xaiv cov slurry ntws ntsuas
Los ntawm daim ntawv teev cov flowmeter xaiv, cov kev xaiv flowmeters uas yuav siv tau rau particle fiber slurry muaj xws li: txawv siab flowmeters xws li lub luj tshib, wedge-shaped leeg, electromagnetic flowmeters, Doppler ultrasonic flowmeters, Vortex flowmeter, phiaj flowmeter, Coriolis loj flowmeter, thiab lwm yam. rau kev siv tam sim no ntawm domestic flowmeters thiab kev ntsuas kev ua tau zoo ntawm ntau yam flowmeters, electromagnetic flowmeters yog thawj qhov kev xaiv rau kev ntsuas slurry txaus, tshwj tsis yog tias cov ntsuas slurry tsis yog-conductive lossis muaj ferromagnetic hais, thiab ntsuas cov kav dej tsis pub txiav. tawm mus Tsuas yog thaum lub ntsuas ntws txuas nrog, lwm cov ntsuas ntsuas tau raug xaiv. Raws li cov lus ceeb toom, ntau xyoo ntawm kev siv hauv kev ntsuas qhov ntws ntawm cov thee-dej slurry nrog pulverized thee cov ntsiab lus txog li 65 feem pua yog suav tias yog qhov zoo dua li electromagnetic flowmeters.
Sib txawv siab flowmeters tuaj yeem siv los ntsuas slurry. Ntxiv nrog rau lub luj tshib, cov leeg zoo li cov hlab ntsha thiab cov hlab ntsha annular, qhov sib txawv ntawm qhov sib txawv kuj tseem siv tau rau cov phiajcim orifice thiab eccentric orifice daim hlau thaum cov khoom theem me me. Venturi raj kuj siv rau kev ntsuas. .
Doppler ultrasonic flowmeter tuaj yeem ntsuas yam tsis tau txiav cov yeeb nkab thiab clamping ib qho ultrasonic transducer (kev sojntsuam) sab nraum cov yeeb nkab, tab sis qhov ntsuas qhov tseeb tsis siab.
Vortex flowmeter tsuas yog ntsuas cov khib nyiab uas muaj cov hmoov me me, thiab cov ntsiab lus ntawm cov khoom yog loj lossis fibrous yuav ua rau lub suab nrov thiab siv tsis tau.
Lub hom phiaj flowmeter yog siv rau cov kua ntws xws li cov roj hnyav lossis cov roj seem uas muaj cov roj pulverized, thiab cov hom phiaj flowmeter yog siv.
Coriolis huab hwm coj flowmeters muaj kev paub dhau los hauv kev ntsuas slurry hauv txawv teb chaws, thiab feem ntau lawv cov raj ntsuas ncaj nraim yog tsim nyog, tab sis tsis muaj ntau yam kev siv hauv tsev.
2. Kev xaiv rau kev ntsuas loj ntawm cov kua hauv cov kav dej kaw
Cov dej ntws loj uas tau hais los saum no tsis yog hais txog qhov "kuj loj txaus" thaum qhov ntws nrawm ntawm qee cov yeeb nkab txoj kab uas hla yog siab, tab sis qhov loj txaus ntawm qhov tseeb ntawm qhov ntws. Txij li thaum qhov khiav ceev ntawm cov kua thauj los ntawm lub raj xa dej muaj qee qhov ntau, qhov kev lag luam khiav nrawm ntawm cov kua dej uas tsis muaj viscosity feem ntau yog 1 ~ 3m / s. Yog li ntawd, qhov kev ntsuas "loj ntws" hais txog ntawm no yog hais txog kev ntsuas ntawm cov kav dej loj ntws.
Feem ntau hais lus, lub flowmeter nrog cov yeeb nkab txoj kab uas hla hauv qab DN300 yog hu ua me me thiab nruab nrab yeeb nkab txoj kab uas hla flowmeter, lub saum toj no DN300 ~ DN400 yog hu ua cov yeeb nkab loj txoj kab uas hla flowmeter, thiab ib tug saum toj no DN1200 yog hu ua ntxiv loj yeeb nkab diameter flowmeter. Feem ntau, cov kua dej ntsuas ntawm cov kav dej loj loj yog cov dej, thiab ntxiv rau cov dej, muaj cov khoom siv roj av. Feem ntau, qhov loj-inch flowmeters suav nrog qhov sib txawv siab flowmeters, electromagnetic flowmeters, ultrasonic flowmeters thiab insertion flowmeters. Kuj tseem muaj qhov zoo hloov pauv flowmeters thiab turbine flowmeters rau DN300 ~ DN500.
(1) Installation tej yam kev mob
Cov kev teeb tsa kev teeb tsa feem ntau yog nyob ntawm seb txoj kev ntsuas puas tuaj yeem tso cai rau cov yeeb nkab ntws tawm thiab kev ua haujlwm raug tshem tawm, seb nws puas tau tso cai rau kev tho qhov ntawm cov yeeb nkab, thiab seb nws puas raug tso cai txiav tawm cov yeeb nkab ntws mus rau. nruab lub flow sensor.
Yog tias lub ntsuas ntws tau tso cai txiav tawm cov yeeb nkab ntws, electromagnetic flowmeters, ultrasonic flowmeters nrog ntsuas cov yeeb nkab seem, qhov zoo hloov pauv flowmeters thiab turbine flowmeters tuaj yeem xaiv.
Extrapolation transducerultrasonic flowmetersthiab insertion flowmeters tuaj yeem xaiv yog tias qhov drilling qhov hauv cov kav dej tau tso cai.
Yog tias cov kev cai saum toj no tsis raug tso cai, koj tsuas tuaj yeem xaiv lub ntsuas ntsuas ultrasonic nrog rau sab nraud clip-on transducer.
(2) Kev ntsuas qhov tseeb
Rau kev tswj xyuas kev hloov pauv yuav tsum tau ntsuas qhov tseeb thiab cov kua dej tsis zoo, ultrasonic flowmeters nrog ntsuas cov yeeb nkab, ntau cov channel ultrasonic flowmeters, qhov zoo ntawm cov flowmeters thiab turbine flowmeters tuaj yeem xaiv, thiab electromagnetic flowmeters tuaj yeem xaiv rau cov kua dej ntws.
Rau kev tswj piv, qhov sib txawv siab Venturi raj thiab sab nraud clamping transducer ultrasonic flowmeter tuaj yeem xaiv nrog qhov ntsuas qhov tseeb qis dua. Optional insertion flowmeter nrog tsawg ntsuas qhov yuav tsum tau muaj.
(3) Kev poob siab (tus nqi siv hluav taws xob)
Tus nqi siv hluav taws xob ntawm kev ntsuas loj txaus suav rau feem ntau ntawm cov nqi ntsuas kev khiav hauj lwm, kev poob siab thiab (tus nqi siv hluav taws xob) xws li qhov sib txawv siab Venturi, qhov zoo hloov pauv flowmeter thiab turbine ntws suav. Qhov me me yog qhov ntxig flowmeter, thiab qhov tsis muaj qhov poob siab yog qhovelectromagnetic flowmeter.
3. Kev xaiv qhov ntsuas dej ntws
Kev ntsuas chav ntsuas tau muab faib ua ob pawg raws li kev ntsuas thev naus laus zis, ib qho yog chav dej superheated thiab saturated chav nrog siab dryness (dryness x=0.9 los yog ntau dua), thiab lwm yam yog saturated chav nrog tsawg dryness. Cov pawg qub tuaj yeem kho tau raws li cov kua dej ib zaug, thaum cov qeb tom kawg yog ob theem ntws. Txij li tag nrho cov flowmeters tam sim no tsuas yog tsim nyog rau cov kua dej ib zaug xwb, qhov tsis tshua muaj dej saturated chav yuav tsum tau kawm ntxiv.
(1) Flow ntsuas ntawm superheated chav thiab siab dryness saturated chav
Feem ntau siv flowmeters yog: throttling sib txawv siab flowmeter, uas tseem yog cov cuab yeej tseem ceeb rau ntsuas cov dej ntws. Piv txwv li, cov cuab yeej throttling, qhov sib txawv siab transmitter thiab pawg peb-valve tau muab tso rau hauv ib qho kev sib xyaw throttling flowmeter. Lub throttling flowmeter daws qhov tsis txaus ntawm qhov sib txawv siab teeb liab lub raj tsis ua haujlwm. Kuj tseem muaj qhov cog throttling qhov chaw, thiab cov qauv nozzles yog siv los ntawm cov qauv orifices. Vim tias cov nozzles tau muab piv nrog cov ntawv orifice, lub outflow coefficient ntawm nozzles ruaj khov, thiab cov outflow coefficient yuav tsis hloov vim lub blunt ntug ntawm lub kaum ntse ntse. Lub siab poob kuj tseem qis dua li ntawm cov phaj orifice. , feem ntau ntawm tib tus nqi ntws thiab tus nqi, qhov poob siab yog li ntawm 30 feem pua rau 50 feem pua ntawm cov phaj orifice.
Lub vortex flowmeter ntsuas nruab nrab kub, uas yog, qis dua 200 degree. Nws yuav tsum tau hais tias daim ntawv thov ntawm chav ua kom paub tab. Nws yog ib hom flowmeter feem ntau siv hauv chav ntsuas tam sim no. Txawm li cas los xij, nws yuav tsum tau muab sau tseg tias qhov nruab nrab uas tsis tshua muaj dryness yuav ua rau lub ntsuas coefficient sib txawv ntawm qhov ntsuas tus nqi thiab nce qhov kev ntsuas yuam kev.
Lub cev tsis sib xws ntawm lub raj flowmeter thiab shunt rotor flowmeter tseem tuaj yeem siv rau hauv kev tswj xyuas sab hauv qhov twg qhov kev xav tau raug tsis dhau siab, vim tias kev siv kuj pheej yig thiab yooj yim, thiab nws yog qhov tsim nyog rau kev ntsuas me me thiab nruab nrab ntws chav. .
Rau lub hom phiaj flowmeter, hluav taws xob thiab pneumatic lub hom phiaj ntws tawm tau tsim nyob rau hauv Suav teb xyoo 1970s yog cov cuab yeej tshawb nrhiav ntawm lub tshuab hluav taws xob thiab pneumatic chav tsev ua ke. Txij li thaum lub zog hloov pauv ncaj qha siv lub zog sib npaug ntawm lub zog sib txawv ntawm lub sijhawm ntawd, nws coj ntau qhov tsis txaus los ntawm lub zog sib npaug ntawm nws tus kheej. Piv txwv li, qhov ntsuas qhov tseeb yog qhov tsawg, qhov xoom taw tes drift, kev ntseeg siab ntawm lub kauj mechanism, thiab qhov tsis zoo. Yog li ntawd, tus thawj JJG 461-1986 "lub hom phiaj ntws transmitter" cov cai tau tsim nyob rau hauv 1986, uas muaj 25 xyoo. Vim hais tias hluav taws xob thiab pneumatic lub hom phiaj ntws transmitters yeej tsis tsim thiab siv. Cov kev cai qub tsis haum rau kev siv, yog li ib qho tshiab
Target Flowmeter raws tu qauv.
Cov qauv ntawm lub hom phiaj flowmeter yog tsim los ntawm lub raj ntsuas, lub hom phiaj phaj, lub zog sensor, thiab lub teeb liab ua haujlwm. Lub zog sensor yog lub ntsuas ntsuas hom sensor, thiab lub teeb liab ua cov zaub tuaj yeem nyeem ncaj qha cov zaub lossis tso tawm cov teeb liab txheem. Lub zog sensor yog tsim los ntawm lub cev cylindrical elastic thiab lub zog ntsuas ntsuas, thiab tuaj yeem ua rau sab hauv lossis sab nraud. Thaum lub cev elastic deforms nyob rau hauv qhov kev txiav txim ntawm quab yuam, nws lov qhov seem ntawm tus choj tsim los ntawm lub zog strain gauges, ua ib qho hluav taws xob teeb liab uas yog squared nrog tus nqi txaus.
Nws txoj haujlwm ua haujlwm yog los teeb tsa lub hom phiaj phaj perpendicular mus rau cov kev taw qhia ntawm cov kab ntws ntws hauv cov yeeb nkab ncaj nraim ntawm ntu ntu ntu. Thaum cov kua hla dhau ntawm lub phiaj phaj, lub phiaj phaj yog raug thawb, thiab qhov loj ntawm qhov thrust yog proportional rau lub zog kinetic ntawm cov kua thiab thaj tsam ntawm lub phaj phiaj. proportional. Tsis pub dhau ib qho ntawm Reynolds tus lej, qhov ntws los ntawm qhov ntsuas ntsuas yog proportional rau lub zog ntawm lub phiaj phaj. Lub zog ntawm lub phiaj phaj yog kuaj pom los ntawm lub zog sensor.
Ua ib lub phiaj xwm ncig ua piv txwv, cov qauv yooj yim rau kev suav suav yog:
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Lub zog ntawm lub phiaj phaj yog hloov mus rau hauv lub teeb liab tam sim no (4-20) mA lossis lub teeb liab cua siab (20-100kPa) los ntawm lub zog hloov pauv, thiab kev sib raug zoo ntawm cov teeb liab tso tawm thiab qhov ntws tuaj yeem raug txiav txim raws li cov qauv saum toj no.
Vim hais tias cov hom phiaj hom hom phiaj tshiab flowmeter muaj cov qauv tshiab thiab ntsuas cov hauv paus ntsiab lus, nws muaj qhov zoo tshaj ntawm daim ntawv thov kev cia siab rau hauv chav ntsuas, thiab tsim nyog rau kev ntsuas qhov me me thiab nruab nrab ntws chav.
(2) Flow ntsuas ntawm qis dryness saturated chav
Cov chav saturated uas ua los ntawm cov boilers dav dav yog saturated chav nrog high dryness (saum toj no 0.95) ntawm lub qhov hluav taws xob, tab sis nyob rau hauv tus txheej txheem ntawm kev thauj mus los ntev, vim muaj ntau yam xws li tsis zoo tshav kub preservation los yog tsis sib haum xeeb. steam siv, lub dryness yog tas li nce. poob, thiab txawm dhau los ua qhov ntub dej nrog cov ntsiab lus dej siab, uas yog, ob-theem kua roj thiab dej. Cov yam ntxwv ntws ntawm ob-theem kua yog qhov sib txawv ntawm cov dej ntws ib zaug. Flowmeter meter coefficients lossis outflow coefficients ntsuas hauv ib-theem ntws tsis tuaj yeem siv rau kev ntsuas ob-theem ntws. Piv txwv li, lub outflow coefficient nyob rau hauv ob-theem flow test ntawm lub orifice flowmeter yuav tsum tau kho kom qhuav. Yog li ntawd, nyob rau hauv lub flow ntsuas ntawm tsawg dryness saturated chav, lub dryness parameter yog ib tug parameter uas yuav tsum tau ntsuas. Nws yog ib qho nyuaj siab tias tsis muaj kev paub tab dryness meter. Tsis tas li ntawd, kev kho dryness ntawm lub meter coefficients ntawm lwm hom flowmeters tsis tau kawm hauv qhov tob. Tsuas yog los ntawm kev daws qhov teeb meem no tuaj yeem ntsuas qhov ntws ntawm qhov tsis tshua muaj dej saturated chav.