Yog li koj tau nqis peev hauv ib qhoultrasonic flow meter. Kev xaiv zoo- tsis muaj qhov txav txav, kev saib xyuas tsawg, qhov raug tsim nyog tawm ntawm lub thawv. Tab sis ntawm no yog qhov tsis muaj leej twg qhia koj ua ntej: qhov tseeb koj pom hauv daim ntawv spec? Qhov ntawd yog nyob rau hauv cov xwm txheej zoo tagnrho. Koj cov nroj tsuag tsis zoo tagnrho. Koj cov kav dej tsis zoo. Tsis muaj dab tsi puas tau.
Cia peb tham txog dab tsi cuam tshuam rau koj kev nyeem ntawv thiab koj tuaj yeem ua li cas txog nws.
Qhov teeb meem ntawm Reynolds Number (Thiab yog vim li cas nws tseem ceeb tshaj qhov koj xav)
Ntawm no yog qhov uas tau nthuav. Lub ntsuas ntsuas ultrasonic tsis ntsuas qhov ntws ncaj qha- nws ntsuas lub sijhawm sib txawv ntawm ultrasonic nthwv dej taug kev mus rau hauv dej thiab nqes. Cov lej suav tias muaj qee qhov nrawm nrawm hla cov yeeb nkab hla -section. Thiab qhov profile? Nws hloov pauv raws li qee yam hu ua Reynolds tus lej.
Thaum Re qis dua 2300, koj tau txais laminar ntws. Cov kua txav mus rau hauv cov txheej txheem sib luag. Lub nrawm profile zoo li parabola- nrawm tshaj plaws hauv nruab nrab, xoom ntawm phab ntsa. Tshaj 4000? Qhov ntawd yog turbulent flow, thiab qhov profile flattens tawm ho. Nyob nruab nrab ntawm 2300 thiab 4000 yog qhov kev hloov pauv hloov pauv tsis zoo uas qhov ntws tsis tuaj yeem ua rau nws lub siab xav ua.
Vim li cas qhov no tseem ceeb? Vim tias koj lub ntsuas ntsuas ntsuas qhov nruab nrab tshaj tawm raws li txoj kev ultrasonic "pom." Yog hais tias nws yog calibrated rau turbulent flow tab sis koj tab tom khiav laminar, koj yuav tau txais ib tug yuam kev. Lub sijhawm.
Qhov kev faib tawm nrawm hauv laminar ua raws li tus qauv parabolic uas qhov nruab nrab tshaj tawm tuaj yeem yog ob npaug ntawm qhov kev tshaj tawm. Nyob rau hauv turbulent flow, qhov profile yog ntau flatter- qhov nruab nrab tshaj tawm tsuas yog kwv yees li 1.2 npaug ntawm qhov nruab nrab. Qhov ntawd yog qhov sib txawv loj thaum koj tab tom sim ntaus ± 1% qhov tseeb.
Flow Velocity Correction Coefficient
Qhov no yog qhov kho kom raug K uas tsis muaj leej twg xav tham txog vim tus lej tau nrawm nrawm.
Txoj kev hloov lub sij hawm ultrasonic ntsuas kev tshaj tawm raws ib qho chord hla cov yeeb nkab. Qhov ntawd tsis yog qhov nruab nrab tshaj tawm uas koj xav tau rau kev suav ntim ntim. Koj xav tau kev kho coefficient los txuas qhov sib txawv.
Rau cov xwm txheej tsis txaus ntseeg, kev sib raug zoo ntawm empirical zoo li:
K=1.119 - 0.011×lg(Re)
Rau laminar ntws, nws yog ib qho sib txawv kiag li:
V̄=KVₗqhov twg Re > 10⁵
Thiab rau Re <10⁵:
V̄=[1.119 - 0.011×lg(Re)]Vₗ=KVₗ
Lub ntsiab lus yog -koj lub meter's firmware tej zaum muaj qee qhov ua tau los ntawm - hauv kev them nyiaj, tab sis nws tau ua qhov kev xav txog koj cov dej ntws. Yog tias cov kev xav no tsis raug, yog li koj nyeem. Qee qhov smarter meters cia koj nkag mus rau cov kua dej viscosity thiab kho tau. Feem ntau tsis ua.
Txoj Cai Ncaj Ncees: Txoj Cai 10D / 5D
Tej zaum koj tau hnov qhov no: teeb lub 'meter' nrog 10 yeeb nkab txoj kab uas hla ntawm txoj kab ncaj nraim mus rau sab saud thiab 5 txoj kab nqes hauv qab. Nws tau luam tawm hauv txhua phau ntawv qhia kev teeb tsa. Dab tsi lawv tsis hais txog txaus yog qhov no yog qhovyam tsawg kawg nkausrau tej yam kev mob huv si.
Puas muaj lub twj tso kua mis? Ntxiv ntxiv. Valve? Ntau. Ob lub luj tshib hauv cov dav hlau sib txawv? Tej zaum koj yuav xav tau 30D lossis ntau dua ua ntej qhov kev khiav dej num nyob rau hauv txaus rau kev ntsuas raug.
Nov yog qhov tshwm sim yog tias koj tsis quav ntsej qhov no: qhov nrawm nrawm dhau los ua asymmetric lossis muaj cov khoom siv swirl. Txoj kev ultrasonic nruab nrab ib yam dab tsi uas tsis sawv cev qhov tseeb txhais tau tias ntws. Koj tau txais tus lej, tseeb. Tsuas yog tsis yog tus yog.
Kuv tau pom kev teeb tsa qhov twg ib tus neeg rub lub ntsuas hluav taws xob tom qab tswj lub valve vim "qhov ntawd yog qhov chaw nyob." Cov ntawv nyeem tau tawm los ntawm 8%. Yim feem pua. Nyob rau ntawm daim ntawv thov kev saib xyuas hloov chaw.
Temperature Compensation-Qhov Tsis Pom Zoo
Qhov ceev ntawm lub suab hauv koj cov kua dej tsis tas li. Nws txawv nrog qhov kub thiab txias. Thiab txij li thaum koj lub ntsuas ntsuas ultrasonic yog qhov ntsuas lub sijhawm, txhua qhov yuam kev hauv lub suab nrawm txhais ncaj qha mus rau qhov yuam kev.
Kev sib raug zoo yog kwv yees li:
C=C₂₀(1 + bT)
Qhov twg C₂₀ yog lub suab nrawm ntawm qhov ntsuas kub (feem ntau yog 0℃lossis 20 degree), b yog qhov kub thiab txias coefficient rau koj cov kua dej tshwj xeeb, thiab T yog qhov ntsuas kub tiag tiag.
Cov ntsuas niaj hnub no feem ntau muaj qhov ntsuas kub ntsuas hauv qhov zoo. Tab sis lawv puas calibrated? Thaum twg lawv tau kuaj zaum kawg? Lub sensor zaum hauv lub thermowell ntsib thermal lag. Thaum lub sijhawm hloov pauv, qhov ntsuas kub ntsuas yuav yog ob peb degrees tawm ntawm cov kua dej tiag tiag.
Rau siab - cov ntawv thov raug, koj yuav xav paub tseeb tias koj qhov nyiaj them rau qhov kub thiab txias tau ua haujlwm raws li qhov xav tau. Ib qho 10℃yuam kev hauv kev nyeem ntawv kub tuaj yeem cuam tshuam koj qhov ntsuas ntws los ntawm 1-3% nyob ntawm cov kua dej.
Transducer Installation Angle thiab Coupling
Qhov no yog qhov teeb meem ntau dua li qhov teeb meem tsim, tab sis nws tseem ceeb.
Ultrasonic transducers yuav tsum tau ua raws li qhov tseeb. Ntawm clamp- ntawm meters, qhov sib txuas ntawm transducer thiab cov yeeb nkab phab ntsa yog qhov tseem ceeb. Cov pa paug, corroded yeeb nkab nto, pleev xim, xeb-ib yam ntawm cov no tuaj yeem ua rau lub teeb liab los yog tsim cov kev xav tsis zoo.
Rau wetted transducers, lub installation lub kaum sab xis txiav txim siab qhov twg ultrasonic beam cuam tshuam qhov ntws. Ob peb degrees tawm, thiab koj ntsuas lub chord uas tsis sawv cev rau txoj kab uas hla koj xav tias nws ua.
Inline meters los ntawm lub Hoobkas feem ntau zoo. Nws yog lub teb installation thiab retrofits qhov twg txhua yam mus sideways.
Lub Teeb Pom Kev Zoo thiab Tau Txais Cov Chaw
Feem ntau cov ntsuas ultrasonic muaj qee yam teeb liab zoo qhia. Ua tib zoo mloog nws.
Lub teeb liab tsis tshua muaj zog txhais tau hais tias lub ntsuas hluav taws xob tau tawm tsam kom pom lub sijhawm hla kev sib txawv kom raug. Qhov no tuaj yeem tshwm sim vim muaj cua nkag los yog cov pa roj npuas, cov khib nyiab tshem tawm ua rau lub teeb liab, cov yeeb nkab phab ntsa degradation, thiab qhov sib txawv ntawm qhov tsis raug ntawm qhov clamp- ntawm kev teeb tsa.
High -meters kawg cia koj kho qhov nce ntxiv kom them nyiaj. Tab sis cranking nce qhov nce kuj ua kom nrov nrov. Muaj qhov chaw qab zib, thiab nrhiav nws qee zaum yuav tsum tau sim thiab ua yuam kev.
Cov Khoom Ua Kua Dej Koj Yuav Tsis Tsom Nyem
Ultrasonic meters ua haujlwm zoo ntawm cov kua dej huv, homogeneous. Tab sis cov txheej txheem kev lag luam tiag tiag tsis yog ib txwm huv lossis homogeneous.
Entrained gas npuas tawg thiab nqus ultrasonic zog. Txawm tias 1-2% roj los ntawm ntim tuaj yeem ua teeb meem. Suspended solids ua tib yam, tab sis cov nyhuv yog nyob ntawm qhov loj me thiab concentration. Cov kua dej khov heev yuav tsis tsim qhov kev xav tau tshaj tawm, tshwj xeeb tshaj yog nyob rau hauv qis qis uas koj yuav muaj feem ntau nyob rau hauv laminar lossis kev hloov pauv hloov.
Paub koj cov kua dej. Yog tias cov xwm txheej hloov raws caij nyoog lossis nrog cov voj voog ntau lawm, koj qhov raug yuav hloov ib yam nkaus.
Multi-Txoj Kev vs. Ib Leeg- Txoj Kev: Thaum Nws Tsim Nyog Kev Txhim Kho
Ib leeg -pab meters yog pheej yig dua thiab yooj yim dua. Lawv xa ib nqaj hla lub yeeb nkab thiab hu nws ib hnub. Qhov tseeb nyob ntawm qhov ntsuas ib zaug uas sawv cev qhov tseeb nruab nrab.
Ntau-pab metres siv 2, 4, lossis ntau dua acoustic txoj hauv kev sib txawv chord. Lawv suav nrog cov lej no kom tau txais qhov kwv yees zoo dua ntawm qhov tseeb tshaj tawm qhov profile. Qhov tshwm sim? Zoo dua qhov tseeb txawm tias muaj kev cuam tshuam txaus.
Yog tias koj tab tom sim nyem txhua feem kaum kawg ntawm ib feem pua ntawm koj qhov ntsuas, ntau - txoj kev yog txoj hauv kev mus. Rau kev tswj cov txheej txheem dav dav qhov twg ± 2% zoo, ib leeg - txoj kev feem ntau ua haujlwm.
Kev Tshawb Fawb thiab Calibration tsis tu ncua
Nov yog kev kuaj xyuas qhov tseeb: tag nrho cov ntsuas ntsuas ntws dhau sijhawm. Ultrasonic meters tsawg dua li feem ntau, vim tsis muaj cov khoom siv kho tshuab, tab sis lawv tsis muaj zog.
Transducer aging, electronics drift, yeeb nkab phab ntsa hloov los ntawm corrosion los yog deposits -txhua yam no cuam tshuam qhov raug. Cov ntawv spec raug yog rau ib qho tshiab, txhim kho kom zoo, khaws cia meter.
Koj ua pov thawj li cas? Cov kev xaiv muaj xws li xa cov ntsuas ntsuas mus rau qhov ntsuas ntsuas ntsuas (khoom kim, yuav tsum tau tshem tawm), siv lub ntsuas ntsuas hauv koob rau kev sib piv (tseem ceeb rau kev siv kua), thiab gravimetric lossis volumetric pov thawj (tus qauv kub tab sis feem ntau tsis siv).
Yam tsawg kawg, sib piv koj cov ntaub ntawv kuaj mob. Lub teeb liab lub zog poob thaum lub sijhawm? Tshawb xyuas. Lub sij hawm thauj mus los drifting? Tej yam hloov.
Kab hauv qab
Ultrasonic flow meter tuaj yeem ua tau zoo kawg nkaus-0.5% lossis zoo dua hauv cov xwm txheej zoo. Tab sis kev ua tiav thiab kev tswj xyuas qhov tseeb yuav tsum tau ua tib zoo saib rau kev teeb tsa, txheej txheem txheej txheem, thiab kev txheeb xyuas tsis tu ncua.
Qhov yuam kev loj tshaj plaws uas kuv pom? Kev teeb tsa tsis zoo tsis quav ntsej txog kev khiav ncaj nraim, tsis saib xyuas qhov kub thiab txias, thiab xav tias lub Hoobkas calibration tseem siv tau tom qab xyoo ntawm kev pabcuam.
Tau txais cov khoom no kom raug, thiab koj yuav tau txais qhov raug koj them rau. Hla lawv, thiab koj kuj yuav tau yuav ib lub meter pheej yig dua.
