Flow Calculations for the V-Cone and Wafer-Cone Flowmeters

Transcription

1 Basic low equation: Flow alculations or the V-one an Waer-one Floweters π g c ΔPps ρ 1 Volue lowrate π lb g c ρ ΔPps s 1 Δ Pps ΔPwc Mass lowrate ac ach gp ac gph ach π Δ PPa Volue lowrate ρ 1 s π ρ Δ PPa Mass lowrate 1 kg s ΔPPa ΔPbar s L 1000 Page 1 h s L h h WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

2 Gas Expansion Factor Precision tube V-one an Insertion Top-plate V-one Floweters (Rev. May 001) The equation or gas expansion or copressible lui low: NOTE: 1 or noncopressible luis (e.g. water, oil etc.). ΔP 1 ( ) k P Note that Δ P an P can be any units as long as they are the sae. Waer-one Floweters (Rev. Oct 001) The equation or gas expansion or copressible lui low: NOTE: 1 or non-copressible luis (e.g. water, oil etc.). 8 ΔP 1 ( ) k P The equation to convert ro actual to stanar / noral volue units: NOTE: This conversion is only use copressible luis. scs P P L b Tb T Zb Z N s s P P L b T T b Zb Z The basic equation ters o : NOTE: is use to sipliy the low equation by cobg the constant an geoetric variables. Page 55 WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

3 ΔPps ρ ΔPPa ρ s Note that calibrate eters have expresse as a unction o Reynols Nuber. Thereore or the case o calibrate eters or will be expresse as unctions o Reynols Nuber. Lear velocity equations: v v throat π π v s s v throat π π Beta ratio an cone iaeter equations: Page 55 WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

4 Beta Ratios: The stanar beta ratios or V-one loweters are: 0.5, 0.55, 0.65, 0.75, an 0.8. Alternative beta ratios can be use i require. Note that ierential pressure an/or gas expansion actor ay liit the availability o even stanar beta ratios. In a liqui application, beta ratios shoul not be use that cause static le pressure us the ierential pressure to be less than the lui s vapor pressure. In vapor or gas applications, beta ratios shoul not be use that generate a gas expansion actor less than 0.8. Reynols nuber equation: Re v ρ 1.9 μ Re μ v ρ The V-one eters ischarge coeicient is relate to the lows Reynols nuber. It is avise that the V-one eter be calibrate across the range o Reynols nubers or which it is to be use. That is a plot o ischarge coeicient to the Reynols nuber shoul be prouce an a le it relatg ischarge coeicient to the Reynols nuber shoul then be ae. Flowg ensity equations: Liquis: Stea: Gas: ρ Gr ρ ρ ρ 1 Sp.Vol. water Sg PL.6988 Z T Metric units: ρ ρ Theral expansion equation: When eters are subjecte to substantially ierent teperatures than those at which they were calibrate, there can be an eect on eter perorance ue to the expansion o the cone an eter tube aterials. Use this equation i the theral expansion coeicients or the pipe an cone are equal: 1+ α T 58 F a Page ( ) 55 WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

5 Use this set o equation i the coeicients are ierent: Fa ((1 α pipe (T 58)) ) ((1 α cone (T 58)) ) To calculate the theral expansion actor at operatg teperature base on beta ratio: ( ) alculate pipe iaeter at operatg teperature: + α ( T T ) alculate cone iaeter at operatg teperature: + ( α ( T T )) alculate beta ratio at operatg teperature: 1 pipe cone c c alculate theral expansion actor at operatg teperature: F a 1 1 The exaple below eonstrates the use o this ter: F (at _ new _ tep) a Peranent pressure loss equation: Peranent pressure (or total hea ) loss ierential pressure eters is typically escribe as a percentage o the ierential pressure create at a particular lowrate. An approxiate V-one Meter peranent pressure loss can be oun by applyg the ollowg equation: ( ) 100 % P loss Page WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

6 Noenclature eter constant etric eter constant ischarge coeicient o the eter eter sie iaeter eet eter sie iaeter ches ' pipe iaeter at operatg teperature ches eter sie iaeter eters eter sie iaeter illieters cone iaeter ches ' cone iaeter at operatg teperature ches cone iaeter illieters F a eter theral expansion actor g c iensional conversion constant,.17 lb / lb sec k lui isentropic exponent at lowg conitions P absolute pressure sae units as ΔP P b base absolute pressure psi (typically psia) P b base absolute pressure bars (typically 1.01 bara) P L absolute static le pressure psi at the eter P L absolute static le pressure bars or psi at the eter volue low rate actual cubic eet per secon ac volue low rate cubic eet per ute ach volue low rate cubic eet per hour gp volue low rate gallons per ute gph volue low rate gallons per hour kg/s ass low rate kilogras per secon L/ volue low rate liters per ute L/h volue low rate liters per hour lb/s ass low rate pouns ass per secon / volue low rate cubic eters per ute /h volue low rate cubic eters per hour /s volue low rate actual cubic eters per secon N /h volue low rate noral cubic eters per hour sch volue low rate stanar cubic eet per hour sc volue low rate stanar cubic eet per R sipliication ter use actor Re Reynols nuber S g speciic gravity o the gas Sp.Vol. speciic volue o the vapor Page WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

7 T lowg teperature egrees Ranke T lowg teperature egrees Kelv T b base teperature egrees Ranke (typically 50 R) T b base teperature egrees Kelv (typically K) T c calibration teperature T' operatg teperature v lui velocity through the pipe, eet per secon v lui velocity through the pipe, eters per secon v throat lui velocity at the throat, eet per secon v throat lui velocity at the throat, eters per secon aiabatic expansion actor or contoure eleents note: 1 or liqui low applications Z lowg gas copressibility actor base gas copressibility actor Z b %P loss peranent pressure loss across the eter as a percentage o ierential pressure Greek sybols: α PE α cone α pipe ' ΔP ΔP Pa ΔP bar ΔP wc pipe an cone aterial coeicient o theral expansion theral expansion coeicient o cone aterial theral expansion coeicient o pipe aterial eter beta ratio beta ratio at operatg teperature ierential pressure sae units as P ierential pressure Pascals ierential pressure illibars ierential pressure ches o water colun μ operatg lui viscosity, centipoise π.1159 ρ lowg lui ensity pouns ass per cubic oot ρ lowg lui ensity kilogras per cubic eter Page WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit. #509-5 Rev../0-08 opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.

8 OTHER McROMETER PROUTS INLUE: Magnetic Floweters Magnetic Floweters Magnetic Floweters Propeller Floweters Floweters An Flow Straighteners For Propeller Floweters Propeller Floweters ierential Pressure Floweters ierential Pressure Floweters ierential Pressure Floweters Electronic Instruentation or Reote isplay an ontrol U.S. Patents 6867, 8109, 56699, 9190 an 5,81,78; anaian Patent 1511; European Patent 07711; Japan patent 1,858,116 Waer-one: Hong Kong Patents HK1076 & HK106605; Other U.S. an Foreign patents peng WEST STETSON AVENUE HEMET, ALIFORNIA 955 USA TEL: FAX: Prte In The U.S.A Lit.#509-5 Rev../0- opyright Mcroeter, Inc. All prte aterial shoul not be change or altere without perission o Mcroeter. Any publishe pricg, technical ata, an structions are subject to change without notice. ontact your Mcroeter representative or current pricg, technical ata, an structions.