CA1057530A - Method and apparatus for measuring mass flow rate of individual components of two-phase gas-liquid medium - Google Patents

Abstract

METHOD AND APPARATUS FOR MEASURING MASS FLOW RATE
OF INDIVIDUAL COMPONENTS OF TWO-PHASE GAS-LIQUID
MEDIUM
Abstract of the Disclosure A method for measuring mass flow rate of individual com-ponents of two-phase medium comprises feeding a flow of a me-dium to be measured through a hollow pendulum, imparting un-damped oscillations to the pendulum, measuring energy requir-ed to maintain a constant oscillation velocity, the mass flow of the medium being assumed proportional to the measured ene-rgy value and the average density of the medium being assum-ed proportional to the measured fundamental frequency of the pendulum, and determining mass flow of each component from mathematical relationships.
An apparatus for carrying out the method for measuring mass flow rate of individual components of two-phase medium comprises a sealed housing accommodating a hollow pendulum supported therein. The housing mounts and electromagnetic coil for imparting undamped oscillations to the pendulum and an electromagnetic coil for converting oscillation velocity.
Output frequency signals of converters are proportional to mass flow rate of two-phase medium and to the density of the two-phase medium being measured.
The apparatus for carrying out the method for measuring mass flow rate of individual components of two-phase gas--liquid medium according to the invention provides for mea-suring mass flow rate of individual components of a two--phase medium without recurrence to additional separation of the flow thus facilitating the measurements and making them more reliable.

Description

lOS7530 ME~HOD AND APP~RATUS FOR M~SURING MASS FIOW R~E
0~ INDIVIDUAL COMPONE~S O~ ~O-PH~S~ GAS-~IQUID
MEDIUM
~ he inven~ion relates to t~e field oi measurem~t o~
ma8s ilow rate of liguids and gaseR, and more particularly to a method and apparat~s for meaæuring mass ilow rate oi indîvidual componen~s of two-p~a~e medium. Measu~ing maæ~
ilow rate of indi~idual componentæ of two-pha~e media i3 an important problem for chemical, iood, oil, gaR a~d petroc~e-mical industries, and t~iR problem is also critical in de-termining ma~8 flow rate of pulverulent and granular product~, aR well as suspensions in conve~ing them along pipelines.
It is known to determine mass ilow rate of individual component_ of two-phaRe media by the met~od comprising preli-minarily separating a mixturo into compone~ts and measuring the maæs flow rate of each compo~ent. ~his method is rather complica~ed and inaccurate æince the accuracy o~ mea~uremen~
depend~ oi the ~uality of separation of a mixture.
It is know~ to measure ~low rate of individual compone~ts o~ two-compone~t ~lows (cf. US~R Inventor's Certi~icate ~o.189170, Int. Ol. G 01 ~, 1966), whereln volumetric ~nd ma85 i~low rates o~ a two-component flow aro mea~ured by U8i~g volumetrlc and mass flow rate ~e~sor~, respectively, which are mounted one after another along the flow pat~. Si~nals proportional to the values of the mea~ured flow r~tes are fed to a computer which solve~ a set o~ two equations with respect to variables representing volumetric and mass flow rates of i~dividual components. ~y t~is method, the influe~-. .

~05753 ce of the shear value on the measurement resul~s is eliminat-ed. I~ this case, the accuracy o~ measurements depends on ~luctuations of the ~low structure, variations o~ ths pattern o~ velocity and pressure fields which are inevitable in di~e-rent point_ o* a pipeline.
~ he above factors result in that the readings o~ volumet-ric and mass flow rate sensors operating in the ~low in dif~e-rent s~ctions oi the pipeline are dif~icult to correlate. In addition, when using the most widely employed flow rate sen-sors with mechanical element~ cooperating with the flow (tur-bines, streamlined bodies,~restrictors), it is necessary to eliminate the effect o~ the ~irst sensor o~ the sensors loca-ted downstreams.
Enown in ths art is a met~od for measuring flow rate of liquid and gas in a ~low of a gas-liquid mixture for sealed oil and gas collection systems, wherein oil and gas ~low toge-ther along a single pipeline (c~. Instruments and Control S~qtems (Pribory i sistemy upravlenija)~ No-10, 1972, Pp.18 -20). In mea~uring flow rate by this method, a rotary volu-metric se~sor i~ u~ed ~or determinabion of the value o~ volu-metric ~low r~te o~ the mixture, as well a~ a standard restri-ctor, such as a diaphragm. With known volumetric flow rate o~
the mixture, which i9 mea~ured by a ~low meter, and pressure difference at the diaphragm, the density o~ the gas-liquid medium can be determined. With know~ density values ~or liqui~
and gas in t~e mixture, volumetric gas content and ~low rates o~ liquid and gas are determined. in so doi~g, the assumption i8 made that the actual volumetric ga~ di~ctribu~ion is ide~ti-cal with the ~low rate distribution. ~his assumption re~ults in large measurement errors. In order to limit the mea~ureme~t errors to 3 - 4%, a special calibration of t~e diaphragm and flow meter should be ef~ected for eac~ mixture to be measured.
Standard diaphragms used for determination o~ ~low rate o~
single-phase liquids mag be used only in ca~e the diaphragm modulus i8 at least 0.5, an~ besides,it is necessary that gas conten~ o~ the Dixture should not exceed 0.5~ In practice, this value is as hig~ as 25.
~ he majority of known methods for measuring mass flow rate of individual components of two-phase media are characterized by the e~ployment o~ a mas~ ~lo~ meter whose measuring quali-ties have t~e paramount effect on the measurement error.
Xnown i~ the art are vibration mass ~low meter~ w~ic~ are very ~lmple and reliable, have ~o rotatable p~rt5 or e~ements obstructing the ~low. Baside~, the vibration mas~ flow meters give readin~8 indepe~dent o~ the visco~ity ô~ a medium being measured.
Known ~ the art is a vibration mass ~low meter (cf. US
Patent No.3080350, Cl. 73-194, 1963; or ~.P- ~atgs, ~utomatic Control System for Velocity and Flow Rate ~ields (Sistema avtomatic~eskogo ~onrolja polej skoro~te; i raskhodov), pp.211 - 214) comprising a cantilevered pipe throug~ whic~
~ flow of a medium being measured ~reely passes out into a lOS7530 reservoir. ~he pipe vibrates at a constant ~requency w~ich i9 clo~e to resonance frequency. ~he ~low meter also comprises a means imparting to the pipe oscillatio~s about an axi~
normal to t~e pipe axist and a means for measuri~g amplitude of the pipe oscillations~ In addition~ the flow meter compri-ses a device for maintaini~g t~e amplitude of o~cillations of the pipe at a constant level and a means for measurin~
the moment applied to the pipe. With the o~cillations ampll-tude remaining consta~t, the value of moment is preparatio~al to mass flow rate~ ~his flow meter cannot, however, be used for measuring mas~ flow rato of two-p~ase mixtures since in measuring mass flow rate of two-phase media with ~ariable phase-to-phase ratio, oscillation ~re~uency of the pipe also varie~ t~us resulting in a non-linear dependence o~ the mo-ment on t~e mass flow rate, hence in a aon~iderable increase in measuremen~ error.
Known in the srt is a vibration mass flow meter (c~. USSR
In~entor's Certificate No.243860, Int. Cl. G on ~, 1967; or Inetruments and Control Systems (Pribory i sistem~ uprsvle-ni~a), No. 11, 1972, pp. 22 - 24) compri~in~ a oa~tilovered tubc performing undamped oscill~tion~ A weight i~ atbached to t~e distal end o~ the tube to stabilize re~onanco froguen-cy o~ the tube ao a~ to eliminate t~e e~fects of fluctuations o~ speci~ic gravity of a medium on the m~asurement result~
and to improve the accuraay of ~ea~uremen~ o~ flow rates of two-phase media. ~he tube is accommodated in a sealed housi~g 80 that the measurement can be performed under high pressures.
~he flow meter also comprises an electromagnet for impartiDg oscillations to the tube, a converter ~or converting mechani-cal o~cillations into electrical and a circuit for mea~uring decrement which i8 proportional to the mass flow rate being measured.
~ is flow meter also cannot be used for measuring flow rates of individual components because data signRls received from the flow meter are proportional to a single parameter only - mass flow rate of a mixture.
Enown in the art i8 still another vibration mass flow me-ter (cf. US Patent No.321885~, Cl. 7~-194, 1965) comprising a sealed housing and a pipe fixed therein by mean3 of lea*
spring~. A flow o* a medium being measured is fcd throug~ the pipe whic~ imparts an oscillatory motlon to t~e ilow. ~he flow meter also comprise~ a mean~ for impartin4 oscill~tions and a converter ~enerating an electric sig~al whic~ i~ propor-tional to the oscillatio~ velocit~.
~ ean~ ~or measuring o~cillatlon ~clocity of the pipe and moans *or imparting oscillations are coupled to eac~ ot~er vla a~ amplifier to form, ln combination wit~ the pipe, a~
electromechanical oscillator. Oscillation velocity o~ the pipe i8 maintained at a consta~t level due to an automatic gain control o~ the ampli~ier using an automatic gain control system. It is noted that t~e e~ergy applied to the oscillating ~057530 pipe is proportional to the mass flow rate of the medium being measured.
It should be, however, noted that this construction of the flow meter does not enable measurements of mass flow rate of each component of a multiphase medium. Output signal of the flow meter is proportional only to the mass flow rate of a single-phase medium and cannot bring any information useful for determination of flow rates of individual components of a medium.
It is an object of the present invention to provide a method for measuring mass flow rate of individual components of two-phase gas-liquid medium.
Another object of the invention is to provide a method for measuring mass flow rate of individual components of two-phase three-component medium.
Still another object of the invention is to provide an apparatus for carrying out~the method for measuring mass flow rate of individual components of two-phase three-component medium according to the invention.
The above objects are accomplished by that a method for measuring mass flow rate of individual components of two-phase gas-liquid medium, according to the invention, comprises feeding a flow of a two-component medium being measured through a hollow pendulum, imparting undamped mechanical oscillations to the pendulum, maintaining a constant oscillation velocity of the pendulum, measuring energy required for maintaining a constant oscillation velocity, the mass flow rate of the ~0s7530 medium bei~g assumed proportional to the measured energy value, measuring fundamental frequency of the pe~dulum, the a~erage density of the medium being assumed proportional to t~e measured fundamental frequency of t~e pendulum, measurisg pressure within t~e pendulum and determi~ing mass ~low rate of each component o~ the medium being measured from the fol-lowing formulae:

G1 = 1 , P 2 J~ 1 0~1 ~2 G2 - ,J~ 1 G1 ~1' wherein G1 is mass flow rate of the liquid p~ase, ~2 is mass flow rate of ga~ as conte~t determined ~rom the formul~. f - c(1 _ ~ 2 ) ~
p ~1 J 1 wherein - is ratio of the average density ~ o~ t~e medium to the densit~ o~ the liquid p~ase ~ 1 wbich is approximately equal to the ratio of the value of current deviation. o~ iunda-mental frequency of t~e pendulum to the value of deviatio~ o~
fu~damental fre~ue~c~ o~ t~e pesdulum ~illed wit~ the liquid pb~Ye, ~ 2 is density of t~e ga~eou~ phase at normal pres~ure, i8 dimensionless value whic~ i~ numericall~ e~ual to t~e adsolute pressure, c is proportionality factor establi~ing the dependence of actual gas content y and flow rate gas content ~, W i8 energy required to compensate for losses occurring during the pendulum oscillations,G 1 is propo*tio-nality factor.
I~ case of oil-water-gas medium, w~erein the ~a~ ~artor is constant for eac~ given oil field and equal to the ra-tio of volumetr~c flow rate o~ gas ~ to volumetric flow rate o~ oil Q3, and w~erein gas content ~ 1 depends only on water content ~ whic~ is determined by the relations~ip~

2b ~ ~4b2 _ 4ac = .
2a w~erein a = (1 - c)( ~4 ~

~f + b1 J~ - b2- C2 = (1 - ~ I C ~ C

b1 = d - C-~2~ b2 = (1 - c)(2~ 3 - ~ 4)~

S~ + C-~P2- c2 ~ C).~3, c2~ o3~ C4 are proportionality ~actor~ oil den~ity, ,"~4 i~ water denRity~ 3 + (-f'4 '~P3) C~ 1 =o~ ) i8 ga~ conte~t~ flow rate oi eac~ component oi t~e liquid p~aRe i8 pre~erably determined irom t~e iollowing formulae:
G3 ~ G1(1 ~), ~057530 _ g _ G4 = ~4 . G1 . ~' w~erein G3 i~ mass flow rate of oil and G4 is ma~8 flow rate of water.
For a two-p~ase tbree-compone~t medium actual volumetric gas con~ent ~ in t~e pendulum i8 al80 preferabl~ measured.
from which t~e gaB co~tent C~1 i8 determined by the formula:

c4 -~the density of the liquid p~ase ~ 1 being determined b~ the formula ~ 1 ~ 5 ~ (~ 6 ~ ~ 5)- ~A~ ~ wherein ~5 i~ de~sit~ of a ~irst ¢omponent of the liguid pbase, 6 ~ 5, and ~1 i8 conte~t of the ~ir~t component of t~e liquid phase in the liquid phase proper which is determi~ed from the relation~hip ~ ~ 5(1 ~~ 2 Y ~ p A
(~ 6 p 5)(1 ~) ~nd the content of each component i8 preferabl~ determined b~
the follow~ng formulae G5 = S G1(1 51 ) ~

G6 = p G1 '~

w~ereiIl G5 is mass flo~r rate of the first component of tbe liquid pbasc, G6 is mass flow rate of the qeoond compo~ent of the liquid phase-10575;~0 ~ he above objects are accompli~hed by that an apparatu~for carrying out the method ~or me~suring mass flow rate o~
individual components of two-phase medium according to the invention comprises a æealed housin~ accommodati~g a hollow pendulum supported therein, oscillations being imparted to the pandulum by means of an electromagnetic co~l mounted on the housinæ, an electromagnetic coil for converting oæcillation ~elocity of the pendulum into an electric signal ~h~ch is al~o mounted on t~e housing, an amplifier having an output connected to the electromagnetic coil imparting oscillations and an i~put connected to the electromagnetic coil ~or converting o~cill~tion velocity, an automatic gain control un~t having an input connected to the electromagnetic coil for converting oscillation velocity and an output connected to a control i~put .. ..
of the a~pli~ier, a ~irst voltage-to-~requency converter having an input connected to the output of the automatic gain control unit, a zero corrector and a con~ersion transcoLductance correc7 tor conuected to the rirst voltage-to-~requency oonverter whose output irequency ~i~nal is proportional to the mas~ ~low rate o~ a two-phase medium being measured, a ~requency-to-voltage conYerter, a second ~olta~e-bo-~r~quency converter havin~ an input conneoted bo the output o~ the frequen¢y-to-voltage converter, a zero corrector and a conver~ion tran~conductance corrector ¢on~ec~
ted to the ~e¢ond coltage-to-frequency con~erter ~ho~e output frequency signal i~ proportionalt to the density of the two-~057~30 -p~a~e medium being measured, a pressure sensor ~or mea~uring pressure o~ t~e two-pha~e medium in the housin~,t~e ~ensor being connected to the in~er space o~ the houæing by means of a pipe.
~ he apparatus preferably comprises an actual volumetric gas content sensor for measuring actual volumetric gas con-tent of a three-component medium in the inner space of the pendulum, the sensor being mounted on the housin~ and having an output connected to the input of a third ~oltage-to-fre-quency converter whose output signal is proportio~al to t~e actual gas content.
~ he passage of the pendulum i8 preferably of an elongated cross-sectional cofiguratio~ with the larger dimension in the direction normal to the plane of the pendulum oscilla-tions~ the cross-sectional dimension in the pla~e of oscilla-tionB~ mass of the pendulum and stif~ness thareof being sele-cted in ~uch a manner that the ratio of resona~ce freguency o~ the pendulum to fundamental frequenc~ of the medium being measured in the lnner space of the pendulum ln the pla~e q~
oscillations is below 0.~, ~ he passage of the pendulum is preferably o~ circular cross-section, t~e diameter d of the circle, mas~ o~ the pen-dulum a~d stiffness thereof being selected in such a mR~er that the ratio of reso~ance frequency of the pendulum to fun-dame~tal frequency o~ the medium be~n~ measured in t~e inner space of the pendulum i~ the plane of osc~llations i8 below 0.1-~ 1057530 ~ he method and apparatus for measuring mass ~low rate of individual components o~ two-phase gas-liquid medium allow for determini~g mass flow rate of eac~ individual component o~ a two-p~ase three-component m;xture. In particular, t~e met~od according to the invention permits determining th~
conte~t of oil, water and produced gas in unseparated oil t~ereby eliminating the step o* separatin~ oi~-water-gas mix-tures in a measuring separator w~ich is now a widelg u~ed practice. ~ho met~od according to t~e invention enables the meaæureme~t~ over a wide dynamic range. ~he apparatus accord-i~g to the invention makes it possible to perform mea~urements o~ mass ~low rate o~ viscous mi~tures ~a~ing a viscosiby of up to 1000 cSt. ~he absence oi rotatable part~ obstructing the ~low o~ a medium being measured in the apparatus according to t~e in~ention simpliiies tho constructio~ o* the vibration flow meter and impro~es tha reliability o~ measurements. ~ho apparatus according to t~e in~ention enables a co~iderable reduction of the number o* control and measuring instrume~ts used for mea~uring mass *low r~te o* two-p~ase media -~ he lnventlo~ will now b~ desorib~d with re*erenoe to aspoci*i¢ embodiment thereo* illustrated i~ the accompanying drawings, in w~ich~
Figure 1 show~ a longitudinal ~ection o* a converter o~
parameters of a two-phas0 gas-liquid medium being mea~ured and a principle block diagram o* a circuit *or measuring ~ig-nals ~rom the converter in an apparatus for carr~ing out the .0575;10 method ~or measuring mass flow rate of indi~$dual components of two-phase medium according to the i~vention;
Figure 2 shows an embodimen~ of a p~e~dulum of the appara-tus according to the invention;
Figure 3 is a transverse sectio~al viow of the pendulum taken along t~e line III-III in ~igure 2;
Figure 4 is a transverse sectional view of t~e pendulum take~ along t~e line IV-IV in Figure 1;
~ igure 5 is a trans~erse 3ectiona1 view o~ another embodi-ment of the pendulum take~ along the line V-V in Figure 1;
Figure 6 is a curve showing the a~pliiier response, w~e-rein ampliiier gain i8 plotted on the ordinates a~d rectified voltage irom t~e electromagnets of t~e co~verter of o~cilla-tion velo¢it~ oi the apparatus according to the i~vention is plotted o~ ths abscissa-~ he apparatus ior carr~ing out the method ior measuringmass ilow rato oi individual components oi two-phase medium according to the invention comprises a sealed housing 1 (~igu-re 1) accommodating a hollow pendulum 2 supported therein.
~e pendulum 2 co~ t~ o~ three part~l a ~olid upper part ~
which is used ior attaahment of the pendulum 2 to the housing 1, a thi~-walled intermodiate part 4 used as an ela~ti¢ suspen-sion, and an enlarged lower part 5 used a~ weig~t.
~ he upper part 3 o~ the pendulum 2 is ~upported, along the periphery of the lower end ~ace 6, by an annular projectio~

iOS7530 - 14 _ 7 of the housing 1~ In this embodiment, the upper part 3 o~
the pendulum 2 is pro~ided with a sealing ri~g 8.
~he upper and lower parts of t~e housi~g 1 have flangos 9 and 10, respecti~ely, w~ic~ are used for connecting the hous-ing 1 to a pipeline.
Mec~anical o~cillations are imparted to the pendulum 2 by means of an electromag~et 11 which ha~ a central ro~ 12 of a core 13 made of a magnetically hard material. ~e electromag-net 11 is mountod on the housing 1 which is made o~ a non--magnetic material. In this embodiment, the housing 1 has in-s~ts 14, 15 and 16 located beneath the electromagnet 11 which comprise plates of a magnetically soft material, suc~ as A A~Mco so as to reduce magnetic stray fields. A coil 17 o~ the electromagnet 11 has two conductors 18 and 19.
~he apparatus also comprises an electromagnet 20 for ¢on-~erting oscillation velocit~ o~ t~e pendulum 2 into an ele-ctric signal. A central rod 21 of the core 22 of the electro-magnet 20 is made of a magnetically hard material. ~he el~-ctromagnet 20 is also mounted on the housing 1. In this em~o-diment, the housing 1 has inserts 23, 24 and 25 oi a magneti-cally soft ~aterial. A coil 26 o~ the electroma~net 20 has two condu¢tors 27 and 28.
q`he apparatus also has a pre~ure sensor 29 for measuring pressure in the inner space 30 of the housing 1. qlhe pressure sensor 29 is connected to the inner space 30 of the housing 1 by means o~ a pipe 31. ~he pipe 31 is connected to the ~ousing ~rc~ d~e r7~c~ r~

1 b~ any appropriate known method, such as welding. Any known sensor generating an electric frequency output signal ma~ be used as the pressure sensor 29.
~ he block diagram for measuring signals ~rom the conver-ter of the apparatus according to the invention comprises a variable gain ampli~ier 32 which is used ~or amplification of the output signal ~rom the electromagnet 20 converting oscil-lation ~elocity of the pendulum 2. T~e amplifier 32 is built around a know~ analog multiplier circuit (cf. V.L. Shilo, ~inear Integrated Circuits in ~adioelectronical ~quipment inejnye integralnye skhemy v radioelectronnoj apparature), Moscow,Sovet~koe radio Publishers, 1974, p.163).
~ n input 33 of the amplifier 32 is connected to the co~-ductor 27 of t~e electromagnet 20 for converting oscillation velocity.Ad output 34 o~ t~e ampli~ier 32 is coDnected to t~e conductor 18 o~ the electromagnet 11 for imparting oscilla-tions-~ e input 33 of the ampli~ier 32 is connected to an input35 of an automatic gain control unit 36. An output 37 o~ t~e unit 36 i5 connected to a oontrol inpub 38 oi th~ amplifler 32 and to an input 39 o~ a ~irst voltage-to-~requency conver-ter 40. An output ~requency signal o~ the ¢onverter 40 i8 rep-re3ented by alternating current at a ~req~oy which i~ pro-portional to the mas~ flow rate o~ the two-phase medium being measured. ~he i~put 41 of t~e converter 40 is connected to an output 42 o~ a zero corrector 43 w~ich is built around a known circuit (cf. V.~. ~hilo, ~inear Integrated Circuits in Radioelectronical Equipment (LinejD~e integralnye skhemy v radioelectronnoj apparature), Moscow, Sovets~oe radio Publi-shers, 1964, p. 128, Fig.4, 13a).
~ e input 44 of the converter 40 is co~nected to an out-put o~ a conversion transconductance corrector 46 which i~
essentially a potentiometer.
~ e block diagram of the apparatus according to t~e in-vention al80 in~ludes a ~reguency-to-voltage converter 47 which is used to convert oscillation frequenc~ of the pendu-lu~ 2 into voltage and is built around a known circuit (cf.
P~V. Novit~kij, V.G. Knorring, V.S~ Gutnikov, Digital Instru-ments with ~re~uency Sensors (~syfrovyo pribory ~ chastotngmi dato~ikami, Energiaa Publishers, ~enigrad, 1970, pp. 275-276, Fig.10-32). An input 48 o~ the converter 47 i8 con~ected to the conductor 27 of the olectromagnet 20 ~or converting oscil-latlon velocit~.
~ n output 49 of the frequenc~-to-voltage converter 47 i~
connected to an lnput 50 of a ~econd voltage-to-irequenc~
converter 51~
An output freguency signal o~ the converter 51 i8 repre-sented by alternating current at a frequency w~ic~ i8 propor-tional to an average density ~ oi the two-phase medium being measured~
A~ input 52 of the con~erter 51 is co~ected to a~ output 53 of a zero corrector 54 which i~ identical with the zero corr~ctor 43. An inpu~ 55 of the converter 51 is connected to an output of a conversion traDsconductance corrector 57 whic~
is identical with the conversion transconducta~ce corrector 46.
For determination of mass flow rate of each individual component of two-p~ase three-component medium, the apparatus is provided with a sensor 58 for measuring actual volumetric gas content. In this embodiment, the ensor 58 compri~es a radioisotope actual ga~ content meter (cf. V.L. Mamaev, G,A.
Odisharin~ Gas DgDam1cs of Gas-~iquid Mixtures in Pipes (Gaso~
dinamika ~azozhidkostnykh smesej v trubakh). Nedra Publishers, Moscow, 1969, pp.92-95).
~ he sensor comprises a radioactive source 59 arranged on the housi~g 1 and a radiation int~nsity meter 60 located at a diametrically opposite ~ide o~ the housing 1-~ n output signal from tha meter 60 is fed to an input 61of a~ amplifier 62 having an integrating circuit at the out-. .
put thereof. An output 63 of the amplifier 62 is co~necbed toan input 64 of a tbird volta~e-to-freguenoy oonverter 65.
An output ~requency sig~al of the converter 65 is propor-tional to actual gas conte~t-~ lternatively, the sensor 58 for measuring actual volu-metric ga~ content m~y comprise a capacitance converter of actual gas content (cf. Hoodendorn C.I., Chemical Eng. Sc., No.9, ~o.4, 1959)-- 1fl -In the latter case, the lower part 5 o~ the pendulum 5 (Fig.2) is made o~ an insulatlng material. ~wo metal plates 66 and 67 (Fig.3) are fixed to the lower part 5 of the pendu-lum to form the plates o~ the capacitance converter. Conduc-tors 68 and 69, respectively, are co~ected to the plates 66 and 67 (Fig.2) which are also connected to a secondary instru-ment 70 ~or measuring the capacity.
An output 71 of the secondary instrument 70 is con~ected to the input 64 of the t~ird voltage-to-frequenc~ converter 65e In this embodiment, a pas~age 72 (Fig.4) of t~e pendulum

2 has a~ elongated cros~-sectional configuration with t~e larger dimension in the direction normal to the plane o~ the pendulum 03cillations and represents a rectangle. It s~ould bo noted t~at the cro~s-~ectio~al dimension in the plane o~
the pendulum oscillations and sti~fness o~ t~e thin-wallod part 4 (~ig.1) of t~e pendulum 2 are selected in such a man-ner t~at t~e ratio of resonance freguency of the pendulum 2 to fundamental frequency of the medium beinB measured in the inner space 72 o~ the pendulum 2 in the plane of oscillations of the pendulum 2 is below 0.1-~ e thin-walled inbermediate part 4 (Fig.1) of the pendu-lum 2 i~ provlded with ridges 73 for reducing deformation of the intermediate part 4 o~ the pendulum 2 under the action of pressure difference at the pendulum 2 during the passage of flow therethrough.

.
~ lternatively, the passage 72 of the pendulum 2 may be of circular cross-section ~Fig.5), t~e diameter d of the circle, mass o~ the pe~dulum 2 and sti~fne~s thoreo~ being selected in such a manner that the ratio of re~onance frequency of the pendulum to fundamental frequenc~ of the medium being measu-red in the i~ner ~pace of t~e pendulum in t~e plane of oscil-lations of the pendulum is below 0.1.
~ he t~in-walled intermediate part 4 of the pendulum 2 i8 provided wit~ two longitudinally ex*ending diametrically op-posite projections 74 intended to create an anisotropy of bending ~ti~fness of the intermediate part 4 (Fig.1) of t~e pendulum 2.
~ he met~od according to the invention will be better un-der3tood a~ter the re~erence to the following simplified the-oretical background o~ the invention.
Differential equation for moments of the oscillating pen-dulum 2 is the following:
~ (b + ~2G)~ + ~ = M, (1) wherein I1 - I2(1 1 I3 ) ~2) I1 i8 moment of inertia o~ t~e pendulum 2 filled with t~e me-dium being measured, I2 is mome~t of inertia of the pendulum 2, I3 is moment of inertia of the modium in the inner space of the pendulum 2, 1 is lengt~ of the pendulum 2, b are pro-per energy losse~ in the oscillating pendulum 2, G is mass ~low rate of two-phase medium which, in case of gas-liquid medium is a total of ma~ flow rate o~ gas G1 and mass flow rate of the liguid phase G2, that i8 G = G1 + G2 (3) i8 bending ~tiffness of the pendulum 2, i8 rotation Pn~le of the pendulum 2, i9 speed of variation o~ the rotation an~le of t~e pendu-lum 2, is acceleration of the rotation angle of the pendulum 2.
Oscillation velocit~ ~ of the pendulum 2 is converted into a proportional electri¢ signal equal to ~ ~ , wherein is coef~icie~t o~ electromagnetic linkage of t~e electro-magnet 20 for converting oscillation velocit~ with the pendu-lum 2, and moment ~ dsveloped by the electromag~et 11 for imparting oscillations is expreQsed as follows:
M _ E E1 ~ (4) wherein E is gain of t~o amplifier 32 coupling the electro-magnet 20 for converbing oscillation ~elooit~ to the ele-ctromagnet 11 ~or impartln4 oaoill~tlons.
B~ ~ubgtibuting (4) into (2) obtai~:
(b ~ 12G - EK1)-~ ~ k ~ = 0 (5) Under stead~ oscillation conditions, where the energ~ ap-plied to the pendulum 2 is equal to the energy absorbed by the pendulum 2 during the passage of the medium being mea~ured theret~rough~ the ~ollowing condition is ~ul~illed:
(b ~ l2G~- EE1)- ~ = (6) wherefrom b 1 12 ~ - Kg1 = (7) -Oscillations of the pendulum 2 ~illed with t~e medium being mea~ured occur at resonance frequencys 2 k k k = . = - - =
I1 I2(1 ~ ~ I2(1 +3 ) I2. mz - ~;)o 1 G) o 1 + E .~~ . (8) ~7 S7 wherein z k (~)o= (9) is ~undamental fre~uency o~ the empty pendulum 2, is density of the medium being measured~
is density of the pendulum material, S is cross-sectional area of the passage 72 of t~e pendulum Z, S7 is cross-sectional area of the pendulum 2, E2 is proportionality ~actor, K2 3 P? s (10) m3 ~8 ma~s o~ a unit of length of the pe~dulum 2 ~illod with the medium being mea~ur~d~
m2 iS ma~8 of a unit o~ length o~ t~ empty pendulum 2.
~ quation (8) may be solved with respect to density o~
t~e medium being measured and tran~formed into the following forms 2 ,, ~0 S7 53UD

wherein fo ~ 2 ~ 2 ~

~ quation (11) expresses the relationship o~ the aYerage densit~ of a two-pha~e medium vs. measured frequency f-~ rom equation (7) obtai~:
E a b1 b1 ' (12) wherein b 12 a = _ , b1 =

~ here~ore, mass flow rate of a mixture is proportionalto the ~ain of the ampli~ier 32 which couples the electromag-net 20 converting oscillation velocity to the electromagnet 11 for imparting oscillations. The gain of the amplifier 32 is equal to the ratio o~ the output current driving the ele-ctromagnet 11 for imparting oscillations to a voltage applied to the input 3~ of t~e ampli~ier 32 from the electroma~net 20 ~or converting oscillatio~ velocity:
i1 ~13) It is obvious t~at, for obtaining linear dependence o~ G
on ~, the value o~ U1 ~ould be maintained con~tant.
~ he value o~ U1 i5 maIntain0d constant by varying the value of current i1 which i9 effected by controlling the gai~ ~ of the amplifier 32. The amplifier 32 has the response shown in ~igure 6 which is described by the following e~ua-tion:
~ = ~ (1 - S0 Y2) (14) :~OS7530 ~erein v2 is gain control voltage of t~e amplifier 32, iB maximum gain E o~ t~e amplifier 32, SO i~ steepness of t~e response curve.
A voltage V2 = Es(V1 Y3) (15) wherein ~ is gain o~ the automatic gain control unit 36, V1 iB recti~ied voltage U1 taken ~rom t~e electromag-net 20 for converting oscillation velociby, V3 i9 comparison voltage of t~e automatic gain con-trol unit 36.
By making equal the expres~io~(12) and (14~ obtain that wherein S0 v2 = 1 - A - B . G, (16 a b A = , B =
~x Emax W~en the pendulum iB not ~illed wit~ a medium to be mea-sured G = 0~ v1 = v1 max' V2 ~ V2 max . (17)w~erefrom S0 v2 max = 1 - ~
By subtract~ng (16) ~rom (17) obtain th~t B

~ V2 = V2 max ~ V2 ~-- G (18) wher~rom S
G - ~V2 = E3 ~v2, (19) that i9 mass flow rate G of a two~p~ase medium is proportio-nal to deviation o~ the gain control voltage of the amplifier ~2.
Since G = G1 + G2 ~057530 and G1 = ~ G2 = ~ 2 ~ ' C~1 = ~ (20)t~e expressio~ ~or the liquid phase flow rate may be written in the ~ollowing form:
G1 = E3 4 v~ 3 ~ 2 (21) 1 ~ ~ 1 +~1 ~,p1 ~ herefore, the basic formulae (11) and (21) are obtained for determinatio~ of mass flow rate of individual compo~ents of two-phase media.
~ he most simple case o~ a two-phase gas-liquid medium is a medium contai~ing two single-component phases: liquid one and gas one. Density o~ such medium is determined by the formula:

~ = ~ 1 S + ~ 21 S (22 w~erein ~ 21 = ~ 2 ~ a9 den8ity under pressure p 1~

~ 1 = pP2 is dimensionles~quantit~ indi~ati~g how many time3 the absolute pressure within the houslng i~
greator th~n atmo3pheric pressure ~3- ~2 i~ gauge pressure~
S1 ~nd S2 are cross-ssctional area~ of the peAdulum occupied by liguid and gas, respectivoly, under pressuro ~ 1.
It i~ obvious that S1 ~ S2 _ S (23) ~us, eguation (22) may be transformed to read P2 ~1) s =~ J2 P1)~ (24) wherein ~ i8 actual volumetric ga~ content.

.

By solving equation (24) with respect to ~ obtai~.

~ (25) f 1 ~ 2 p1 ~ here is an empirical relationqhip of actual ga~ content value vq. flow rate gas cont~nt~ for the mo~t frequentl~
occurriDg structure of gas-liquid mixturo w~ich is characte-riz~d b~ t~e dependence of ~ on ~ and Fr ~umber (cP. V.A.
Mamao~, G.E. Odi~harin, ~.I. Semenov, ~.~. Tochigin~ Hydro-dynamics of Ga~-Liquid Mixtures in Pipe3 (Gidrodi~amika gazozhidko~tn~k~ smose; v trubakh), ~edra Publishers, 1969, P-146~ Figs 56 a~d 57).

~ = 0~81~ o~2~2 ~ ) (26) It follows from t~e expre~sion (26) that wit~ ~ufficien-tly hig~ Proude numbers for air-water mixtures, actual gas oontent ~ 0.81 ~ and doos not dopend on tho Froude number for the mi~ture, that is self-similar flow occurs during t~e passago of a two-p~aso medium t~roug~ the pendulum 2.
In ca~o of non-ascendont and ~orizontal flow~ ~ol~--similar flow condltions are obtai~ed with Froudo numbers F~ ~ 4, and in ca~b of descende~b flowe, depending on tho nature of two-p~a~o medium~ ~elf-similar ~low cond~tio occur at bigher Froudo numbers.
~ e ¢onstruction of the pendulum 2 in tho apparatus ac-cording to the invention provides for independence of ~ on Fr numbor o~or the entire measuring range so t~at ~ 3 = ~ . Q21 (27) whorein ~ is coei~icient w~ich is to be experime~tally e~ta-blished ~or a giYen constructio~ of tho pendulum 2 and ior a speciiic medium being measured, Q21 = p 2 volumetric ~low of the gaseou~ phase~at t~o pressure ~,.
~aXing into account that Q Q1 ~ Q21 (28) and C~ obtain ~ ; = P 1 ~ ~ (29) Among the torms oi aguation (25) den~ity of liguid f 1 and densit~ oi gas f 2 are known~ pi8 mea~ured, densit~ o~
the mix~ure is detormined from oguation (11), ~ is determi~od from deviations of tho ~aluos of fO and i, ~nd then, from tho expression (25), a~d ~i8 determi~ed from ~ormula (29~.
After ~inding out ~ 1 a~d ~ubstitutin4 it i~to (21), mass flow rate oi liguid p~se G1 of the modium boin~ moasu-r~n~ ca~ be determined. Volumetric flow rate o~ gase~ w phase i8 determined by the ~ormula- .

Q2 = C~1 Q1 ~~ 0) ~or products of oil wells whic~ represent an oil-water--ga~ medium wherein the Iiquid pb~so consi~ts oi two compo-~057S30 nents - water and oil~ the ratio of oil to oil ga~ is a con~tant value ~or a given oil field and i~ expres~ed b~ t~e ~ormula:
2 ~ Q3 (31) whorein ~ is the ga~ factor. Due to the fact that the gas factor is unchanged with time and is know~ ~or given measuro-ment conditions, ma~ flow rate of each individual compone~t of an oil-water-gas medium can bs determined wit~out perfor-ming any additional mea~urements.
After determination of density ~ of t~e medium by ~ormula (11), water content ratio may be found. ~or an oil-water-ga~
medium, the following formulae ¢an be used:

f 1 ~3 ( f4 ~3) cr (32) ~ 1 = C~ C ) (33) wherein ~ 3 is den~ity of oil, ~ 4 is density of water~ C~ is water content ratio.
Since the ~alue of ~ depend8 on the value of water con-bont ratio and i9 a~ unknown guanti~y, obtain, by ~ub8titut-ing (25) in (29)s (34) ~ (1 _ p ~2 ) - (1 - ~ ) Aiter eubstitution o~ value ~ ~1 from (32) and ~ ~ 1 ~rom (33) in (34), a quadratic equation i3 obtained fro~
whic~ water content ratio i~ to be found:

~057530 _ 28 --( 1~ b2)~ ~ a1 ~ ~6b2)p~ 2l4Lp~ a~

2 p (1 - ~ ) wherei~a1 ~f ~ , b2 = ~ ~ 3 (36) Now, t~e flow rate of componants o~ an oil-water-gas me-dium may be determined from the following ~ormulae:

Q3 = ~ 3 = ~ Yolumetric ~lo~ rate of oil (37) Q = G4 = ~ . ~ volumetric flow rate o~ (38) ~4 ~1 w~ter Q2 = ~ Q3 = ~ volumetric flow rate of ga~ (39 : - ~ 3 ~ e most complicatod is the determination o~ ~low rates o~ individual components o~ a two-p~aQe medium in the case, whero t~e liquid p~asc consists of two components, and t~e ratio of all t~ree components mag arbitra~ly vary durin~
the measureme~t-In ~uc~ appllcation8aotual ~a~ con~ent is to be additio-nally measured.
Average density of a medium i8 determined from equation (11)-T~e ~ollowing relatio~sbip sta~ ~or den~ities o~ the liguid pha~e and v~. densittes o~ components thoreo~:
~ 1 S1 = ~5 S5 ~ 6 S6 = ~5-S5 ~ 6(S1 ~ S5) (40 -- 2~ _ wherein ~ 5 and ~ 6 are den~itie~ o~ first and second compo-. ne~t~ of the liquid phase, respectivel~, a~d ~ 6 >~5- S5 and 86 are portion~ of the cro~s-section o~ the pe~dulum 2 oocu-pied by the first and second components, respecti~ely.
Rela~i~e content oi the fir~t component in tbe l~guid phase is determined by t~e eYpression S
~1 ~ S ~ (41) t~en equation (32) may bo rewritten a~ ~ollows:
P1 = ~5 1 ( ~6 ~ 5) ~1 (42) By substituting expression (42) i~ (24) ~5 ma~ bo found ~rom the following:

Q1 ~6 -~ 5)(1 -y j ~~~ (43) und c~1~ G1~ G5~ G6 and ~2~ e~pre~sions (35), (21 (37), (38), (30) are u~ed wit~ substitution ~ ~ 1 for ~, C~1 ~or ~ G1 and ~ ~or G3 and ~3-~ be basic relatioLsblps determining the operatlon oi tb~apparatu~ for carrying out the mot~od accordin~ to the in~en-tion aro true~ ir a numbr of co~ditions are ~ od. ~e sguation (1) is solvod wit~ t~e a~sumption that a gas-liquid ~edium i8 a guasi-homogeneous non-elasti¢ liguid with varia-ble density. ~his a~sumptio~ iB quito founded ~ince tho measu-rement~ o~ voltage ~ V2 proportional to the value of mass flow rate of two-p~a~e medium and frequency proportional to average den~it~ o~ the medium are performed during a finite time i~t~rval, and the quantities used în ths derivation oi the equation have the value~ averagod over t~is time inter-val.
Iinear dependence oY actual and flow rate gas content hol~a over a predetermined flow rate range is maintained, ii the pendulum cross-~ectional area i~ selected in such a manner that t~ere occurs a self-similar two-p~a3e ~low over the entire range of measurement of mass flow rate oi two--p~a~e medium.
In order to comply with the condition of non-compre~si-bility of liquid, a predetermined ratio oi pendulum oscilla-tion irequency and fundamental ireguency oi gas-liquid modi-um in the inner space of the pondulum s~ould bo maintained whic~ i3 ac~ieved by selecting predetermined s~ape and di-mensional proportioning of the pendulum on the ba~is of the following con~ideration~.
Gas-liquid medium filling t~e pendulum cavity cannot be attribubed to the category of non-compressible media duo to t~e pre~once o~ ga~ t~erein. Elasbicity o~ bb~ medium re-sults in the appdr~nce t~eroin oi oscillation~ normal to tho ilow direction. ~h~refore, the pendulum and elastic medium filling it form two interrolated oscillating ~ystems. ~in-~a~e ~actor of two ~y~tam~ i~ determined by t~e ratio of their ~undamental ~requencies, ela~tici~y oi a two-pha~e me-dium and viscosity thereof.

~57530 In order to impart oscillations to a two-phase medium, a certain energy should be applied. T~is additional ener2~ in-troduces an error into t~e value o~ the measured mass flo~
ratec This energy is imparted to particles o~ the medium from the pendulum walls. Oscillatio~s in a gas-liquid medium pro-pagate at the acoustic velocity and depend on the value of ~low rate gas content ~ = Q (44) Oscillation ~requency o~ a two-phase medium may be appro-ximately found ~rom the ~ollowing expression:
~ = C7 (45) herein C7 is acoustic velocit~ in the medium, is ~ree path length o~ acoustic wave which is de-termined, ln thi~ case, by the cross-sectional di-mensio~ of the inner space of the pendulum.
~ he pendulum o~cillations constitute an external distur-bant force for the medium filling it. Amplitude o~ 08cilla-tions o~ the medium depend~ on the ~reguency ratio o~ the pen-dulum and medium and on the decrement o~ t~e medium. If the ratio ~ pendulum 0.1 ~ medium then the relative amplitude of oscillations o~ a two-phase medium becomes close to unit so that energy take~ off by the oscillating medium is minimized. Wit~ an increased visc08ity oi the medium, this eifect is ac~ieved at higher ra~ios o~
C~pendulum to G~medium.
If the condition pendulum i9 fulfilled for medium minimum acou~tic velocities in a two-phase medium (about 18 -- 25 m/s), in all other cases t~e ratio ~ pendulum/G~medium will be still lower. Hence, the in~luence o~ gas~ uid me-dium o~ the losseR in the pendulum and on the error in measu-rements of mass flow rate of the medium will be smaller. ~his condition may be fuliilled by using a pendulum in which t~e inner space is shaped as a flat passa~e. ~he size of the pas-sage cross-section of the pendulum coinciding with the plane of oscillations is selected suc~ as to compl~ with the ¢on-ion pe~dulum/ ~medium ~ 0-1~ and ~atio o~ the 8aid 8ize to the widt~ o~ the passage should provide for sel~-similar ~low conditions over a desired flow rate range.
Anisotrop~ of bending stiifness due to which tha elastic suspen~ion oi the pendulum has m;nimum stif~ness in the plane extending through the housing axi~ a~d centera o~ the olectro-ma~nets i~ ensured by tho pendulum shape whio~ 18 made oi a rigid rectangular tube.
~ he pendulum may be of circular cro~s-section- With th~s construction o~ the pendulum, ani~otropy of bending stiffness of the elastic suspen~ion o~ the pendulum iB pro~ided ~or due to the presence of two longitudinally extending projec-tions on diametrically opposite passage walls. ~hiB shape ~057530 of the pendulum is used in the cases where the diameter of t~e pendulum pa~sage provides ~or ful~illment o~ the bot~
pendulum/~medium ~ 0-1 and sel~-similar flow conditions, or where t~e pendulum cros~-section ha~ baffles providing to comply with these conditions.
~ he apparatus according to the invention operates in t~e ~ollowi~g m~n~er:
~ flow o~ a two-phase two-component medium, whic~ repre-sents a ga~-liguid mixture, i8 fed throug~ t~e ~ollow pe~du-lum 2. Undamped mechanical oscillatio~s are imparted to the pendulum 2, and to the~e mec~anical oscillabions correspond electric oscillation~ in t~e electric circuit o~ the electro-mec~anical oscillator including tho electromagnet 11 for imparting o~cillations, the pendulum 2, the electromagnet 20 for converting oscillation velocity and t~e automatically controlled ampli~ier 32.
Oscillation~ develop~d~ in the circuit occur at a frequen-cy wbic~ i~ e~ual to ~undamental ~requency o-~ t~e pendulum 2 ~illed with the two-p~ase medium being measured. ~he pendu-lum 2 oscillates to interact with the permanent magnetic field of t~e electromagnet. ~8 a re~ult, an ~MF is iDduced in t~e coil 26 o~ the electromagnet 20 w~ich i8 proportional to oscillation velocity o~ tbe pendulum 2.
~ he alternating ~F U1 i8 ~ed to the input 33 of the amplifier 32. ~mplified signal i8 ~ed from the output 34 of the ampli~ier 32 to the inpu~ 18 o~ the coil 17 of the ele-- 105753(~

.
ctromagnet 11 for imparting oscillations.
~ he provision of decreasing characteristic of the ampli-fier 32 (Fig.6) enables steady oscillations of the pendulum 2.
, ~e amplitude of oscillation velo¢it~ of t~e pendulum 2 i8 set-up by the Retting voltage V2 to which the voltago U1 is continuousl~ compared.
Automatic control unit 36 maintains the initial value oi the amplitude of oscillation velocity of the pendulum 2 at a constant levol. ~e ~low o~ medium passing through the pendu-lum 2 takes off a part o~ the energy required to maintain the oscillation amplitude unchanged. ~hus, the automatic gain control unit 36 generates a signal directed to increase the gain o~ t~e amplifier 32 by applying thereto a voltage V1 - V3 - V2- ~e excitat1on current flowing in the coil 17 of the eleotromagnet 11 for imparting oscillations i8 respe-ctive}y incr0ased.
Ya~8 flo~ rate of liquid medium i~ determi~ed by the va-lue of the control voltage V2-~ he control voltage V2 received from t~e oubput o~ theautomatlo ~ain control unlt 36 proportlonal to the mass ~low rate is fad to the input 39 of t~e voltage-to-*requency con-vorter ~0 having the zero corrector 43 and the conversion transcondu¢tan¢e corrector 46. Due to the provision of these corre¢tors, it i8 poss~ble to ~et-up zero and 8uch steepness for any p.endulum independent o~ manu~acturing deviations of parameter~ thereof ~o that all pendulums will have identical conversion c~aracteristics.

~0 5~75~3~D

~ h0 voltage U1 ~rom the electromagnet 20 i8 ~ed to the input 48 o~ t~e frequency-to-voltage converter 47 a~d then, ~rom the output 47 thereof, to the input 50 o~ the voltage--to-frequency converter 51 ~ving the zero corrector 54 and the conversion transconductance corrector 57.
Double fr~quency voltage conversion is necessar~ to ob-tain identical conversion characteristics ~or different pen-dulums. ~he output ~requency o~ the voltage U1 is proportio-~al to avera~e density of the two-p~ase medium being measu-red.
At the same time, the preRsure in the inner space 30 o*
the sealed housing 1 is measured w~ich i8 egual to the pres-sure at the outlet o~ the pendulum 2. ~he measurement is ef-~ected by me~ns o~ the pressure sen~or 29 ~aving ~ ~requency output sigual. Wit~ the known pre~ure valuo, the parameters o~ t~e gaseous phase may be reduced to the measurement con-ditions.
In order to detormine ~low rates o~ individual component~
o~ a two-pha~e medium in which the liguid pha~e con~i~t~ o~
two relativel~ ~oluble compone~lt~, actual gas content ~hould be additionally measured. ~he gas content is measured by mea~ of a radi~activo ~ensor 58, ~e inten~ity o* radia~ion o* the 90urce 59 o~ the sensor 58 i5 proportional to actual ga~ content in the plane o~ the source 59.
~ h0 output signal of the sensor~ which is represented by ~requenc~r, is proportional to actual gas content of the me-dium being measured.

~057530 -- 36 _ ~ he met~od for measuring mass flow of individual compo-nents of two-phase gas-li~uid medium according to the inven-tion and the apparatus for carrying out this method enable the determ;nation of mass flow o each component o~ a two--phase two-component medium and two-phase three-component medium. ~hu~, the method according to the invention allows ~or measuring the content of oil, water and lateral gaq in non-separated oil thereby eliminating the process o~ separat-ing oil-water-gas mixture~ in a measuring separator. ~e met~od accordi~g to the in~ention e~ables the measuremen~s over a wide dynamic range, a~ well a~ measurement~ of mass ~low rate of viscou~ mixtures with a viscoslty of up to 1000 cSt. ~he ab~ence of rotating parts in the construction of the apparatus which could ob~truct the passage of Ylow o~
a medium to be mea~ured simpliiigs the construction o~ the vibration flow metor and improves the reliability o~ measure-ments. ~he apparatus according to t~e invention ensures a considerable reduction o~ the number of control and measuring in~truments for mea~uring ma~s *low rate of two-p~ase media.

Claims (9)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A method for measuring mass floe rate of individual components of two-phase gas-liquid medium comprising feeding a flow of a tow-component medium to be measured through a hollow pendulum; imparting undamped mechanical oscillations to the pendulum; maintaining oscillation velocity of the pen-dulum at a constant level; measuring energy required for maintaining constant oscillation velocity; the mass flow of the medium being assumed proportional to the measured energy;
measuring fundamental frequency of the pendulum; the average density of the medium being assumed proportional to the measu-red fundamental frequency of the pendulum; measuring pressure of the medium within the pendulum housing; determining mass flow rate of each individual component of the medium being measured by the following formulas:

wherein G1 is mass flow rate of the liquid phase, G2 is mass flow rate of the gaseous phase, ? 1 is gas content which is determined by the realtionship:

wherein is ratio of average density of the medium to density of the liquid phase ?1 which is approximately equal to the ratio of the value of current deviation of fundamental frequency of the pendulum to the value of deviation of funda-mental frequency of the pendulum filled with the liquid phase;
?2 is density of the gaseous phase at normal pressure, ? is dimensionless quantity which is numerically equal to the ab-solute pressure; C is proportionality factor between actual volumetric gas content ? and flow rate gas content .beta.; W is energy required to compensate for losses occurring during the pendulum oscillation; C1 is proportionality factor.

2. A method according to Claim 1, wherein,in case of oil--water-gas medium, the gas factor .alpha. is a constant value for each given oil field and is equal to the ratio of volumetric flow rate of gas Q2 to volumetric flow rate of oil Q3; the gas content .alpha.1 depends only on water content ? which is de-termined by the relationship:
wherein a = (1 - C)(?4 - ?3), 2b = ? + b1? - b2, , , b2 = (1 - C)(2?3 - ?4), , C2 = (1 - C)??3, C2, C3, C4 are proportionality factors, ?3 is oil density, ?4 is water density, ?1 = ?3 + (?4 - ?3)?
.alpha.1 =.alpha.(1 - ?) is gas content, flow rate of each component of the liquid phase is determined by the following formulae:

wherein G3 is mass flow rate of oil, G4 is mass flow rate of water.

3. A method according to Claim 1, comprising the step of additionally measuring, for a two-phase three-component me-dium, actual volumetric gas content ? in the pendulum determi-ning gas content .alpha. from the relationship:

the density of the liquid phase ?1 being determined from the relationship ?1 = ?5 + (?6 - ?5) ? ?1 wherein ?5 is density of a first component of the liquid phase; ?6 is density of a second component of the liquid phase, and is content of the first component of the liquid phase in the liquid phase proper which is determined from the relationship:

the content of each component of the liquid phase is determi-ned from the following formulae:
wherein G5 is made flow rate of the first component of the liquid phase, G6 is mass flow rate of the second component of the liquid phase.

4. An apparatus for carrying out the method for measur-ing mass flow rate of individual components of two-phase me-dium comprising: a sealed housing; a hollow pendulum accommo-dated in said sealed housing; an electromagnetic coil for imparting oscillations to said pendulum, said coil being mounted on said housing; an electromagnetic coil for convert-ing oscillation velocity of said pendulum into an electric signal, said coil being mounted on said housing; an amplifier having an input connected to the electromagnetic coil, which converts the oscillation velocity of the pendulum and a con-trol input, the output of said amplifier being connected to said electromagnetic coil for imparting oscillations; an auto-matic gain control unit having an input connected to said electromagnetic coil for converting oscillation velocity and an output connected to said control input of said amplifier;
a first voltage-to-frequency converter having an input con-nected to said output of said automatic gain control unit; a first zero corrector connected to said first voltage-to-fre-quency converter; a first conversion transconductance corre-ctor connected to said first voltage-to-frequency converter whose output frequency signal is proportional to mass flow rate of a two-phase medium being measured; a frequency-to--voltage converter having an output; a second voltage-to-fre-quency converter having an input connected to said output of said frequency-to-voltage converter; a second zero corrector connected to said second voltage-to-frequency converter; a second conversion transconductance corrector connected to said second voltage-to-frequency converter whose output fre-quency signal is proportional to density of the two-phase me-dium being measured; a pressure sensor for measuring pressure of the two-phase medium in the inner space of the housing.

5. An apparatus according to Claim 4 comprising: an actual volumetric gas content sensor for measuring actual volumetric gas content of a three-component medium in the inner space of the pendulum, said sensor having an output and being mounted on said sealed housing; a third voltage-to-frequency conver-ter whose output frequency signal is proportional to actual gas content, an input of said third converter being connected to said output of said actual volumetric gas content sensor.

6. An apparatus according to Claim 4, wherein the passage of the pendulum has an elongated cross-sectional configuration with the larger dimension in the direction normal to the plane of the pendulum oscillations, the dimension of the cross-section in the plane of oscillations, mass of the pendulum and stiffness thereof being selected in such a manner that the ratio of resonance frequency of the pendulum of funda-mental frequency of the medium being measured in the inner space of the pendulum in the plane of the pendulum oscillations is below 0.1.

7. An apparatus according to claim 5, wherein the pendulum passage is of circular cross-section, the diameter of the circle, mass of the pendulum and stiffness thereof being selected in such a manner that the ratio of the resonance frequency of the pendulum to fundamental frequency of the medium being measured in the inner space of the pendulum in the plane of oscillations thereof is below 0.1.

8. An apparatus according to claim 5, wherein the pendulum passage has an elongated cross-sectional configuration in the direction normal to the plane of oscillations of the pendulum, the dimension of the cross-section in the plane of oscillations, mass of the pendulum and stiffness thereof being selected in such a manner that the ratio of resonance frequency of the pendulum to fundamental frequency of the medium being measured in the inner space of the pendulum in the plane of oscillations thereof is below 0.1.

9. An apparatus according to claim 5, wherein the pendulum passage is of circular cross-section, the diameter of the circle, mass of the pendulum and stiffness thereof being selected in such a manner that the ratio of resonance frequency of the pendulum to the fundamental frequency of the medium being measured in the inner space of the pendulum in the plane of oscillations thereof is below 0.1.