CN1853088A - Apparatus and method for compensating a coriolis meter - Google Patents

Abstract

A flow measuring system is provided that provides at least one of a compensated mass flow rate measurement and a compensated density measurement. The flow measuring system includes a gas volume fraction meter in combination with a coriolis meter. The GVF meter measures acoustic pressures propagating through the fluids to measure the speed of sound alpha<SUB>mix </SUB>propagating through the fluid to calculate at least gas volume fraction of the fluid and/or the reduced natural frequency. For determining an improved density for the coriolis meter, the calculated gas volume fraction and/or reduced frequency is provided to a processing unit. The improved density is determined using analytically derived or empirically derived density calibration models (or formulas derived therefore), which is a function of the measured natural frequency and at least one of the determined GVF, reduced frequency and speed of sound, or any combination thereof. The gas volume fraction (GVF) meter may include a sensing device having a plurality of strain-based or pressure sensors spaced axially along the pipe for measuring the acoustic pressures propagating through the flow.

Description

Be used to compensate the equipment and the method for coriolis meter

The cross reference of related application

Present patent application requires the rights and interests of following patented claim: the U.S. Provisional Patent Application No.60/579 that on June 14th, 2004 submitted to, 448 (procurator's document CC-0745); The U.S. Provisional Patent Application No.60/570 that on May 12nd, 2004 submitted to, 321 (procurator's document CC-0739); The U.S. Provisional Patent Application No.60/539 that on January 28th, 2004 submitted to, 640 (procurator's document CC-0704); The U.S. Provisional Patent Application No.60/524 that on November 25th, 2003 submitted to, 964 (procurator's document CC-0683); The U.S. Provisional Patent Application No.60/512 that on October 20th, 2003 submitted to, 794 (procurator's document CC-0668); The U.S. Provisional Patent Application No.60/510 that on October 10th, 2003 submitted to, 302 (procurator's document CC-0664); The U.S. Provisional Patent Application No.60/504 that on September 22nd, 2003 submitted to, 785 (procurator's document CC-0657); The U.S. Provisional Patent Application No.60/503 that on September 16th, 2003 submitted to, 334 (procurator's document CC-0656); The U.S. Provisional Patent Application No.60/491 that on August 1st, 2003 submitted to, 860 (procurator's document CC-0643); The U.S. Provisional Patent Application No.60/487 that on July 15th, 2003 submitted to, 832 (procurator's document CC-0641); These patented claims are being hereby incorporated by reference.

Technical field

The present invention relates to be used to measure the equipment of the density and/or the mass flowrate of the stream that wherein is entrained with gas, more specifically, relate to and be used for measuring sound and spread the speed broadcast so that determine the gas volume branch rate (gas volume fraction) that this process flows, thereby increase the equipment that expands or proofread and correct the measurement result of the density of Coriolis (coriolis) meter and/or mass flowrate by this.

Background technology

Coriolis meter is widely used in industrial flow measurement, and representative is a part maximum and that increase fast on the flowmeter market of industry.Coriolis meter is celebrated with high precision, and mass rate and the density fundamental measurement result as them is provided.

Since this technology since beginning to be adopted first the 1980s by industry member, coriolis meter has been enjoyed the reputation of a kind of high price, high precision meter, is used for high value applications-mainly be in chemical treatment industry.Yet, although they have these successes, coriolis meter still owing in two-phase flow-mainly be that poor-performing is perplexed in the flow of bubble of gas/liquid mixture.

Coriolis meter has two basic problems for inflation or flow of bubble.At first, flow of bubble proposes the challenge of operability aspect to coriolis meter.Most of coriolis meters use the Electromagnetic Drive driver, make the natural frequency vibration of stream pipe with it.The pipe that these meters depend on vibration generates Coriolis force, and it makes a leg (leg) of stream pipe lag behind another leg.Coriolis force, and be phase lag therefore, be proportional to the mass rate of logical flow tube ideally.Stream pipe like this, is strong (strong) function of damping in the system for specifying the needed exciting force of Oscillation Amplitude in the holding tube typically with resonant frequency or approach resonant frequency and be energized.Single-phase mixture is introduced very little damping to the vibration of bend pipe, yet the damping amount in the system increases significantly with the introducing of bubble.As a result, need more power to remain on the vibration in pipe in the flow of bubble.Usually need than available more power, thereby cause " stall " of coriolis meter.

And coriolis meter often needs the often quick change relevant with the beginning of bubble or aerated flow relatively, stream pipe resonance frequency of a large amount of time and regulates.The stream pipe is essentially it and has greatly been weakened the utilizability of coriolis meter in many two-phase flows and transient response very important use by these time-delays of stall, such as batch processing.Many manufacturers are all solving this stall problem all the time and at present.

The second, polyphasic flow has proposed the challenge of precision aspect.The precision challenge that is proposed by the aerated flow situation is: the many bases hypothesis relevant with the principle of work of the coriolis meter more and more out of true that constantly becomes with the introducing of aerated flow.The invention provides a kind of means that are used to improve to the precision of all types of fluid-operated coriolis meters, be focussed in particular on the precision of enhancing two-phase flow of bubble and potpourri operation.

Summary of the invention

Purpose of the present invention comprises a kind of instrument, it has the equipment that is used for determining sound speed of propagation in ducted fluid stream, so that determine the gas volume branch rate of in pipeline process of flowing fluid or stream, and increase expansion with the density of improving coriolis meter and/or measurement of mass flow rate result's precision.

According to the present invention, be provided for measuring the flow measuring system of the density of the fluid that in pipeline, flows.This flow measuring system comprises coriolis meter, flow measurement device and processing unit.Coriolis meter has at least one pipe that wherein flows through fluid.Coriolis meter provides the frequency signal and/or the phase signal of phase differential of indication between pair of pipes of the natural frequency of inditron.Flow measurement device is measured the speed that sound is propagated by fluid.Flow measurement device provide following at least one of them: the frequency that reduces of the GVF signal of gas volume branch rate and indication fluid reduces frequency in the SOS signal of the speed that indication sound is propagated by fluid, the indication fluid.Processing unit is according to the measurement of mass flow rate result of the next definite compensation of at least one item in SOS signal, GVF signal and frequency signal that reduces and the phase signal and/or according to SOS signal, GVF signal and the frequency signal that reduces and the definite density measurements that compensates of this frequency signal.

To more understand above-mentioned purpose, characteristic and advantage with other of the present invention by following detailed description of illustrative embodiments of the present invention.

Description of drawings

Fig. 1 is the synoptic diagram according to flow measuring system of the present invention, is used for providing density and/or the measurement of mass flow rate that increases expansion for the gas of carrying secretly in the fluid stream that flows through at pipeline.

Fig. 2 is the synoptic diagram according to another flow measuring system of the present invention, is used for providing density and/or the measurement of mass flow rate that increases expansion for the gas of carrying secretly in the fluid stream that flows through at pipeline.

Fig. 3 is the functional block diagram according to the processing unit of flow measuring system of the present invention, as to be similar to Fig. 1.

Fig. 4 is according to synoptic diagram of the present invention, that do not have the model of the coriolis meter that fluid flows through.

Fig. 5 is according to synoptic diagram of the present invention, that the model of the coriolis meter that fluid flows through is arranged.

Fig. 6 is according to compressible, synoptic diagram that the model of the coriolis meter that aerated fluid flows through is arranged of the present invention, that consider aerated fluid.

Fig. 7 is according to the natural frequency of of the present invention, the pipeline curve map as the function of the gas volume branch rate of fluid stream.

Fig. 8 is according to of the present invention, the frequency that the reduces curve map as the function of the gas volume branch rate of fluid stream.

Fig. 9 flows the synoptic diagram of heterogeneity to the influence of the pipe of coriolis meter according to of the present invention, fluid.

Figure 10 is a synoptic diagram heteropical according to compressibility of the present invention, that consider aerated fluid, that the model of the coriolis meter that aerated fluid flows through is arranged.

Figure 11 be according to of the present invention, under the different critical damping of gas relation pseudodensity as the curve map of the function of the gas volume branch rate of fluid stream.

Figure 12 be according to of the present invention, for the curve map of the natural frequency of pipe frequency different a plurality of coriolis meters, that reduce as the function of the gas volume branch rate of fluid stream.

Figure 13 is the synoptic diagram according to the air facility of of the present invention, coriolis meter/carry secretly.

Figure 14 be according to of the present invention, with the 100Hz resonant frequency, have the pseudodensity of coriolis meter of 1 inch diameter pipe as the curve map of gas volume branch rate function.

Figure 15 be according to of the present invention, with the 300Hz resonant frequency, have the pseudodensity of coriolis meter of 1 inch diameter pipe as the curve map of the function of gas volume branch rate.

Figure 16 be according to of the present invention, when the volume change of the air of carrying secretly, the curve map that the pseudodensity of coriolis meter, the pseudodensity of correction and gas volume fraction are pass by in time.

Figure 17 is according to of the present invention, the frequency that the reduces curve map as the function of speed of sound.

Figure 18 is according to of the present invention, density factor and the mass rate factor curve map as the function of gas volume branch rate.

Figure 19 be according to of the present invention, when the volume change of the air of carrying secretly, the mass flowrate of coriolis meter, the mass flowrate of correction and gas volume fraction and the curve map of passing by in time by the mass flowrate of mag instrumentation amount.

Figure 20 is according to schematic block diagram of the present invention, gas volume branch rate meter.

Figure 21 is the schematic block diagram according to another embodiment of of the present invention, gas volume branch rate meter.

Figure 22 be according to of the present invention, from being used for measuring the k ω figure of the data that sound handles by the array of pressure sensors of the speed of the fluid stream of pipeline.

Figure 24 is according to the curve map of speed of sound of the present invention, fluid stream on different pressure limits as the function of gas volume branch rate.

Embodiment

Coriolis meter provides for the mass rate of the fluid stream 12 that passes through pipeline 14 and/or the measurement of density.As noted in detail, coriolis meter provides the mass rate and the density measure of error when the gas of carrying secretly (for example band bubble gas) at the fluid stream memory.The invention provides and be used to compensate coriolis meter so that means correction or improved density and/or mass flow measurement to be provided.

As shown in Figure 1, an embodiment who embodies flow measuring system 10 of the present invention comprises coriolis meter 16, speed of sound (SOS) surveying instrument 18 and processing unit 20, be used to provide any one or a plurality of following fluid flow parameters, that is: gas volume branch rate, sound spread the density of the speed of broadcasting, uncompensated density, compensation and synthetic by fluid.Fluid stream can be the fluid or the potpourri of any inflation, comprises liquid, slurry, solid/liquid mixture, liquid/liquid mixture and any other polyphasic flow.

In the present embodiment, coriolis meter 16 provides the frequency signal 22 and/or the phase signal 23 of phase lag of indication in the pipe of coriolis meter of natural frequency of pipe of the coriolis meter of indication carry fluid 12.SOS surveying instrument 18 provides indication sound to spread the SOS signal 24 of the speed broadcast by fluid.Processing unit 24 is handled frequency signal, phase signal and SOS signal, so that previously described at least one fluid flow parameters to be provided.Pressure and/or temperature signal 26,28 also can be provided to processing unit 20, and it can be used for providing the more accurate measurement of gas volume branch rate.Pressure and temperature can be measured by known devices, or estimated.

Coriolis meter can be any known coriolis meter, 2 inches bend pipe coriolis meters making such as the MicroMotionInc. by me and by Endress ﹠amp; 2 inches straight tube Coriolis meters that Hauser Inc. makes.Coriolis meter comprises a pair of bend pipe (for example, U-shaped, kink (pretzel) shape), or straight tube, as what after this describe.

SOS measuring equipment 18 comprises any device that is used to measure the speed that sound propagates by aerated flow 12.A kind of method comprised along the axially isolated a pair of sonac of pipeline 14, the wherein flight time of the ultrasonic signal of propagating between ultrasonic transmitter and receiver.The characteristic that depends on stream, the frequency of ultrasonic signal must be low relatively, to reduce to flow interior scattering.This meter is similar to the U.S. Patent application No.10/756 that submits on January 13rd, 2004, describes among 922 (the CiDRA document No.CC-0699), and this patented claim is being hereby incorporated by reference.

Alternatively, as Fig. 2, shown in 20 and 21, the SOS surveying instrument can be gas volume branch rate (GVF) meter, it comprises sensing equipment 116, have a plurality of along pipeline axial ground isolated sensor 118-121 based on strain or pressure, be used for measuring the acoustic pressures of propagating at stream 12 190.GVF meter 100 determines and first signal 27 of the SOS of indication in fluid and the secondary signal 29 of the gas volume branch rate (GVF) of indication stream 12 is provided that this will describe in the back in more detail.

Functional block Figure 30 of the flow measuring system of Fig. 3 displayed map 2.As shown in the figure, GVF meter 100 is measured the acoustic pressure of propagating in fluid, to measure speed of sound α _MixGVF meter is by using the speed of sound measured the gas volume branch rate of Fluid Computation and/or the natural frequency that reduces at least.But the GVF meter also pressure of use stream (process flow) is determined gas volume branch rate.Pressure can measured or estimation.

In order to be identified for the improved density of coriolis meter, the gas volume branch rate of calculating and/or the frequency that reduces are provided to processing unit 21.Improved density by operational analysis therefore Density Calibration model that obtain or that rule of thumb obtain (or obtain formula) be determined, it is the natural frequency measured and at least one GVF, the frequency that reduces and the speed of sound of determining or the function of their any combination, and this will describe in the back in more detail.Improved density measurements is the density of the aerated flow that passes through in pipeline.

The present invention also conceives the improvement composite signal of determining aerated flow.In other words, knowing sound by spreading after the speed of broadcasting and improved density, processing unit 21 can be determined the density of fluid/potpourri part of polyphasic flow.

For example, the density (ρ of aerated flow _Mix) relate to volume phase branch rate (volumetricphase the fraction) (φ of each component _i) and the density (ρ of component _i).

${\mathrm{\&rho;}}_{\mathrm{mix}}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&phi;}}_i{\mathrm{\&rho;}}_i$

Wherein continuity requires:

$\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&phi;}}_i=1$

System 10 provides the improved measurement of the density of aerated flow.For two-component mixture, know density (ρ _Gas), gas volume branch rate (or SOS) and accurately measure mixture density (ρ _Mix) density (ρ of the non-pneumatic part of definite fluid stream just is provided _Nongas) means.For example, flow for two component flow:

ρ _mix＝ρ _nongasφ _nongas+ρ _gasφ _gas

So ρ _Nongas=(ρ _Mix-ρ _Gasφ _Gas)/φ _Nongas, φ wherein _Nongas=1-φ _Gas

ρ wherein _MixBe the density of potpourri, ρ _Nongas, φ _NongasBe respectively density and the phase place branch rate and the ρ of the non-pneumatic component of fluid stream _Gas, φ _GasBe respectively the density and the phase place branch rate of the gas in potpourri, carried secretly.

So, know the density (ρ of gas/air _Gas), the gas volume of the measurement of gas divides rate (φ _Gas) and will be the improvement density measure (ρ of the aerated flow of the gas carried secretly compensation _Mix) make it possible to determine the density (ρ of the non-pneumatic part of aerated flow 12 _Nongas), this provides the improved composite signal of aerated flow 12.

The present invention also conceives compensation or improves the measurement of mass flow rate of coriolis meter 16, as shown in Figure 3.In order to be identified for the improved mass flowrate of coriolis meter, gas volume branch rate of calculating and/or the frequency that reduces are provided to processing unit 21.Improved mass flowrate be by operational analysis mass rate calibrating patterns that obtain or that rule of thumb obtain (or the formula that obtains thus) be determined, it is the phase differential (Δ ) measured and at least one GVF, the frequency that reduces and the speed of sound of determining or the function of their any combination, and this is with description in more detail in the back.In order to be identified for the improved density of coriolis meter, gas volume branch rate of calculating and/or the frequency that reduces are provided to processing unit 21.Improved density be by operational analysis Density Calibration/parameter model that obtain or that rule of thumb obtain (or the formula that obtains thus) be determined, it is the natural frequency measured and at least one GVF, the frequency that reduces and the speed of sound of determining or the function of their any combination, this description in more detail in the back.Improved mass flow measurement result is the mass flowrate by the aerated flow of pipeline.

Though improved mass rate and improved density measure can be the functions of GVF, SOS and the frequency that reduces, it can be such as air damping ζ that the present invention imagines these improved measurements _GasThe function of other such parameter.

And though functional block diagram display processing unit 21 can improve the density measure of density measure and coriolis meter 16, the present invention imagines processing may only compensate or improve one of density and mass flowrate parameter.

Confirmed by deterioration for the result of the lumped parameter model of the Figure 10 that after this provides owing to the cognitive precision of quilt of length inflation, vibrating tube densimeter.This model can be used for the role that several of illustrations qualitatively fit over dimensionless (non-dimensional) parameter of the performance of this meter in the aerated fluid.Can reach a conclusion from these models, gas volume branch rate plays a leading role, and comprises air damping ξ _GasAlso influence performance with several other parameters of the frequency that reduces.

Though the model of simplifying can provide some understanding to the influence of various parameters, because the complicacy of inherence heterogeneous, astable fluid dynamic perfromance, quantitative model still is difficult to definition.And, the difficulty well-known devices not only by coriolis meter from be operated in uniform, metastable parameter space relevant with proofread and correct the influence inflate in the decipher density of liquid is deformed to the equipment that is operated in complicated, heterogeneous, the non-stable operating space and complicated, and can not determine accurately that by current coriolis meter the aeration quantity that exists is complicated in handling potpourri.

The invention provides a kind of method, wherein the measurement of the speed of sound of process fluid integrates with the natural frequency measurement of vibrating tube densimeter, has the system of ability enhancing, that accurately operate in aerated flow with formation.Introduce real-time speed of sound and measure and just solved the influence of on a plurality of levels, inflating, be intended to make density measure based on vibrating tube can continue under the situation of the air that existence is carried secretly to approach reporting fluid density for the precision of aerated liquid not.The second, the measurement that obtains of the real-time measurement of speed of sound and gas volume branch rate is utilized by the correction factor that rule of thumb obtains then, improves the decipher of the natural frequency of the measurement of vibrating tube aspect the density of aerated fluid.The 3rd, the combination knowledge of aerating mixture density and aerating mixture speed of sound enables to determine on-inflatable liquid component density, and improved composite signal is provided.Should be pointed out that liquid phase comprises neat liquid, liquid mixture and liquid/solid mixtures.

Described improve aerated liquid, based on the method for the precision of the density measure of vibrating tube.For most of densitometers, the existence of little but unknown entrained gas phasor can be introduced very big error in the decipher density of mixture density of measuring and liquid phase in handling potpourri.

One embodiment of the present of invention are described a kind of method of measuring fluid density, its measure based on the speed of sound of sonar with in Coriolis quality and densitometer, use usually, combine based on the density measure of vibrating tube, with the density of definite aerated liquid.As everyone knows, the precision of coriolis meter can worsen widely for the inflation of process fluid.Increasing the output of expanding coriolis meter with the speed of sound measurement provides a kind of method of novelty, so that improve the density measure for aerated flow in two ways.The gas volume branch rate and the compressible real-time measurement based on first principle of the process fluid of inflation at first, are provided based on the gas volume branch rate measurement of speed of sound.The second, the speed of sound of process fluid can be used for the influence for the output of Coriolis density measure of the compressibility of increase of make-up air potpourri and unevenness.

Be used for lumped parameter model influence, simplification that vibrating tube is inflated in order to illustrate that inflation influence the basic mode of vibrating tube density measure, to have formed.The influence of this specification of a model inflation is attributable at least two independently mechanisms: 1) the density heterogeneity of Li San bubble, and 2) because the potpourri compressibility of the increase that inflation causes.Analysis result obtains the support of experimental data, and they show: increase expansion with the speed of sound measurement and strengthened widely to approach to determine for the precision of aerating mixture not the ability of the density of aerated liquid from the density measure of coriolis meter.

The Coriolis density measure

Though it is many that the concrete design parameter of coriolis meter 16 has, and change, all coriolis meters in fact all are aeroelasticity equipment.Aeroelasticity is the noun that development is come out in the air science of the dynamic interactive research (for example static state of aircraft and dynamic response under aerodynamic force) of the hydrodynamic of describing coupling and structural dynamic system.Coriolis flowmeter depends on the aeroelasticity response of the vibrating flow tube 302 that characterizes fill fluid, to determine mass flowrate and process fluid density measurements, sees Figure 23 and 24.

The physical principle that is used for the deterministic process fluid density in coriolis meter 16 is similar to the principle of using in vibrating tube densimeter.In these equipment, the density of process fluid 12 is by density relevant be determined of the natural frequency of the pipe of fill fluid with process fluid.For this principle is described, consider the vibratory response of the stream pipe of filled vacuum.

In this model, show schematically that as Fig. 4 oscillation frequency is by effective stiffness (the stiffness) (K of pipe _Struct) with the effective mass (m of pipe _Struct) between ratio provide.

$f_{\mathrm{nat}}=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{K_{\mathrm{struct}}}{m_{\mathrm{struct}}}}$

Fluid is incorporated into pipe, has changed the natural frequency of vibration.Under the quasi-steady and uniform model of fluid 12, the main influence of fluid is the inertia load to pipe.Fluid typically has insignificant influence for the stiffness of system.Therefore, in the framework of this model, the quality of fluid 12 directly is added to the quality of structure, schematically shows as Fig. 5.

The quality of fluid 12 is proportional to fluid density in pipe, so natural frequency increases with fluid density and reduces, and describes as following:

$f_{\mathrm{nat}}=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{K_{\mathrm{struct}}}{m_{\mathrm{struct}}+{\mathrm{\&beta;\&rho;}}_{\mathrm{fluid}}}}$

Wherein β is the constant of the calibration relevant with vibration characteristics with the geometry of vibrating tube.

By rearranging, at the natural frequency f of the measurement of vibrating tube _NatAnd the algebraic relation formula between the fluid density in the pipe can be written as following formula:

${\mathrm{\&rho;}}_{\mathrm{fluid}}=\frac{1}{\mathrm{\&beta;}}(\frac{K_{\mathrm{struct}}}{{\left(2\mathrm{\&pi;}\right)}^2{f}_{\mathrm{nat}}^2}-m_{\mathrm{struct}})$

After the definition effective mass of fluid and the ratio between the architecture quality were α, the natural frequency that adds the pipeline of carrying object was given:

$f_{\mathrm{nat}}={\mathrm{<figure-callout\; id="1"\; label="f\; s"\; filenames="A20048002650800311.png,A20048002650800352.png"\; state="\{\{state\}\}">f</figure-callout>}}_s\sqrt{\frac{1}{1+\mathrm{\&alpha;}}},$ Wherein $\mathrm{\&alpha;}\&equiv;\frac{m_{\mathrm{fluid}}}{m_{\mathrm{struct}}}$

This basic framework provides the accurate means that are used for determining the process fluid density under most of conditions of work.Yet, about fluid 12 some basic assumption with the interaction of structure can worsen under different conditions of work.Particularly, the proterties of aerated fluid is different with monophasic fluid with two important mode in the pipe of vibration: the compressibility of increase and fluid heterogeneity.

The fluid compressibility

As everyone knows, most of aerated liquid are more compressible significantly than on-inflatable liquid.The compressibility of fluid is directly connected to the speed of sound and the density of fluid 12.

Mixture density and speed of sound can interrelate by the density and the speed of sound of following mixing rule and component, and these rules can be applicable to potpourri single-phase and that scatter well, and are formed for the air based measurement of carrying secretly based on speed of sound.

${\mathrm{\&kappa;}}_{\mathrm{mix}}=\frac{1}{{\mathrm{\&rho;}}_{\mathrm{mix}}{a}_{{\mathrm{mix}}_{\&infin;}}^2}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{{\mathrm{\&phi;}}_i}{{\mathrm{\&rho;}}_i{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="A20048002650800362.png,A20048002650800421.png"\; state="\{\{state\}\}">i</figure-callout>}}^2}$

Wherein ${\mathrm{\&rho;}}_{\mathrm{mix}}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i{\mathrm{\&phi;}}_i$ And κ _MixBe the potpourri compressibility, and φ _iIt is component volume phase branch rate.

Consistent with above relational expression, air is incorporated into the compressibility that has increased potpourri 12 in the water widely.For example, under environmental pressure, the compressibility of air is higher approximately 25,000 times than water.Therefore, add 1% air of carrying secretly, make the compressibility of potpourri increase by 250 times.Conceptive, dynamic effects is introduced in this increase of compressibility, and it makes that the dynamic perfromance of the proterties of aerating mixture is different from the dynamic perfromance of incompressible monophasic fluid basically in the pipe of vibration.

The compressible influence of fluid 12 can be integrated in the lumped parameter model of vibrating tube, schematically shows as Fig. 6.The stiffness of spring is represented the compressibility of fluid.When compressibility levels off to zero the time, spring stiffness convergence is infinite, and model becomes and is equivalent to the situation that provides on Fig. 5.

As in the past, the effective mass of fluid 12 is proportional to the density of fluid and the geometric configuration of stream pipe.The natural frequency of the first horizontal acoustic pattern can be used for estimating the suitable spring constant of this model in the conduit of circular section.

$f=\frac{1.84}{\mathrm{\&pi;D}}{a}_{\mathrm{mix}}=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{K_{\mathrm{fluid}}}{m_{\mathrm{fluid}}}}$

Should be pointed out that the wavelength of this frequency corresponding to the sound oscillation of about two diameters, that is, this transverse mode is closely relevant with pipe " half-wavelength " acoustic resonance.Fig. 7 shows that the resonant frequency conduct of the first horizontal acoustic pattern of 1 inch pipe is entrained in the function of the gas volume branch rate of the air in the water under standard temperature and pressure (STP).For the low-level air of carrying secretly, it is quite high that the frequency of the first horizontal acoustic pattern is compared with the typical structure resonant frequency of the coriolis meter of 100Hz, yet acoustic resonance frequency descends apace with the increase of the level of entrapped air.

When characterizing aeroelastic system, the frequency parameter that definition reduces usually is easily with importance interactive between the dynamic system that is determined at coupling.For filling out fluid filled vibrating tube, the frequency that reduces can be defined as the ratio of the natural frequency of the natural frequency of structural system and fluid dynamics system.

$f_{\mathrm{red}}=\frac{f_{\mathrm{struct}}D}{a_{\mathrm{mix}}}$

F wherein _StructBe the natural frequency of the pipe in the vacuum, D is the diameter of pipe, and a _MixIt is the speed of sound of process fluid.Using for this, is insignificant because the frequency that reduces is compared with 1, so system approaches quasi-steady work.Under these situations, all compressible models as shown in Figure 6, that ignore fluid are suitable mostly.Yet the influence of instability increases with the frequency that more and more reduces.For given coriolis meter, the potpourri speed of sound has for the change in the frequency that reduces and accounts for leading influence.Fig. 8 shows 1 inch diameter pipe for the structural natural frequencies with 100Hz, as the frequency curve chart that reduces of the function of entrapped air.As shown in the figure, the frequency that reduces is quite little for the water of on-inflatable; Yet, dividing rate and make up apace with the gas volume that increases, this indicates compressible importance to increase with gas volume branch rate.Yet when the Coriolis timing of considering to change design parameter, the increase of pipe natural frequency or pipe diameter will increase the influence for the instability of given air-fill levels.

The fluid heterogeneity

Except the compressibility that increases fluid 12 widely, inflation is returned fluid and is introduced heterogeneity.Be entrained in the stream situation in the continuous flow field of liquid for gas wherein, the single order influence of inflation can be carried out modeling by using bubble theory.By consider to be comprised in have ρ density, non-glutinousness, the incompressible fluid and be arranged to move by fluid, density is ρ ₀The motion of incompressible ball, the speed of indication ball is given:

$V_{\mathrm{sphere}}=\frac{3\mathrm{\&rho;}}{\mathrm{\&rho;}+{2\mathrm{\&rho;}}_0}{V}_{\mathrm{fluid}}$

For the gas that great majority in the liquid are carried secretly, the density of ball is about the magnitude that is lower than fluid density, and the speed of bubble is near three times of fluid velocity.

Consider this result in the context that in the cross section of ball, moves in vibrating tube, the level of the participation vibration that the motion of the increase that ball is compared with residual fluid must cause a part of remaining fluid to have reducing, thus the apparent system inertia (apparent system inertia) that reduces caused.

Fig. 9 shows the lumped parameter model for heteropical influence in the vibration of the pipe of filling the liquid of inflating.In this model, the bubble 40 of volume fraction φ is striden the compensation quality that fulcrum 42 is connected to the fluid with volume 2 Γ.Fulcrum is connected to exterior tube 44 rigidly.The influence of glutinousness can be connected by use and limit bubble 40 and be modeled with respect to the damper 46 of the motion of the remainder of liquid and pipe itself.All the other volumes of liquid are filled the fluid with non-glutinousness on pipeline section (1-3 Γ).Under the restriction of non-glutinousness, the compensation quality of fluid 48 (2 Γ) does not participate in vibration, and the speed of the little bubble of quality becomes three times of pipe speed.The influence of this relative motion is to reduce effective inertia of tube fluid to being filled (1-3 Γ) that this pipe provides by uniform fluid doubly.Under the restriction of high glutinousness, the damping constant of increase makes the relative motion between bubble and liquid minimize, and effective inertia convergence 1-Γ of the fluid of inflation.By this inflation but effective inertia of predicting of model of incompressible fluid vibration in pipe and under the restriction of high and low glutinousness, those model unanimities that provide by (Hemp etc., 2003).

People should be appreciated that processing unit can use these models independently or with lumped parameter model.

The lumped parameter model of combination

Provide model for the influence of inflating vibrating tube densimeter, wherein compressibility and heteropical influence are solved independently.Figure 10 show by use above formation, the specific model of mechanism incorporates the synoptic diagram of the lumped parameter model of compressibility and heteropical influence into.

The formula of the motion of above lumped parameter model is supposed to separate and is had e ^StForm, wherein s is a complex frequency, can be represented as with nondimensional form:

$\left[\begin{array}{cccccc}s+{2\mathrm{\&alpha;\&zeta;}}_{f}Q+{2\mathrm{\&zeta;}}_s& 1+{\mathrm{\&alpha;Q}}^2& {-2\mathrm{\&alpha;\&zeta;}}_{f}Q& {-\mathrm{\&alpha;<figure-callout\; id="1"\; label="Q"\; filenames="A20048002650800311.png,A20048002650800352.png"\; state="\{\{state\}\}">Q</figure-callout>}}^1& 0& 0\\ -1& \mathrm{<figure-callout\; id="0"\; label="s"\; filenames="A20048002650800352.png,A20048002650800362.png"\; state="\{\{state\}\}">s</figure-callout>}& 0& 0& 0& 0\\ {2\mathrm{\&zeta;}}_{f}Q& {-Q}^2& (1-3\mathrm{\&Gamma;})s+{2\mathrm{\&zeta;}}_{f}Q+{2\mathrm{\&zeta;}}_g& Q^2& {-2\mathrm{\&zeta;}}_{\mathrm{<figure-callout\; id="0"\; label="g"\; filenames="A20048002650800352.png,A20048002650800362.png"\; state="\{\{state\}\}">g</figure-callout>}}& 0\\ 0& 0& -1& \mathrm{<figure-callout\; id="0"\; label="s"\; filenames="A20048002650800352.png,A20048002650800362.png"\; state="\{\{state\}\}">s</figure-callout>}& 0& 0\\ 0& 0& {-2\mathrm{\&zeta;}}_{\mathrm{<figure-callout\; id="0"\; label="g"\; filenames="A20048002650800352.png,A20048002650800362.png"\; state="\{\{state\}\}">g</figure-callout>}}& 0& 2\mathrm{\&Gamma;s}+{2\mathrm{\&zeta;}}_{\mathrm{<figure-callout\; id="0"\; label="g"\; filenames="A20048002650800352.png,A20048002650800362.png"\; state="\{\{state\}\}">g</figure-callout>}}& 0\\ 0& 0& 0& 0& -1& s\end{array}\right]\left\{\begin{array}{c}{y}_1\\ x_1\\ y_2\\ x_2\\ y_3\\ x_3\end{array}\right\}=0$

The parameter of arranging the dynamic response of this model defines in following table 1.

Symbol	Explanation	Definition
			α Q ζ f ζ s ζ g τ y	Quality is than the nondimensional time derivative of intrinsic frequency than the critical damping ratio nondimensional time x of the critical damping ratio structural system of the critical damping ratio structural system of fluid system	m fluid/m struct ω fluid/ω struct b fluid/(2m fluidω fluid) b struc/(2m structω struc) b gas/(2m fluidω struct) tω struct dx/dτ

Table 1: for definition lumped parameter model, that arrange the dimensionless group of the formula that moves that is filled with the pipe of compressible aerated fluid

Solve six above-mentioned rank eigenvalue problems, the means of various parameters to the influence of the density of observation of assessing just are provided.The natural frequency of the main pipe die formula of predicting by the eigenvalue analysis is imported into from frequency/density metastable, homogeneous model, is as follows with the pseudodensity of determining fluid 12:

${\mathrm{\&rho;}}_{\mathrm{apparent}}=\frac{{\mathrm{\&rho;}}_{\mathrm{liq}}}{\mathrm{\&alpha;}}(\frac{f_s^2}{f_{\mathrm{observed}}^2}-1)$

As base line condition, analyze " representational " coriolis meter with the parameter that in table 2, provides.

Symbol	Explanation	Numerical value
			f s α ζ struct ξ fluid ξ gas Q D	The structure frequency quality of pipe is than critical damping ratio-structure critical damping ratio-fluid critical damping ratio-gas frequency ratio pipe diameter	1.0 inches of being determined by the speed of sound in the air/water of STP and structural parameters of 100Hz 1.25 0.01 0.01 0.01

Table 2: the parameter of regulation baseline vibrating tube densimeter

For given coriolis meter, the level of inflation has for the difference between mixture density reality and apparent and accounts for leading influence.Yet, also play an important role by other parameter of lumped parameter model sign.For example, the damping parameter ζ relevant with respect to the motion of tube fluid with bubble _GasBe the parameter of dominating system to the response of inflation.ξ _GasInfluence to the pseudodensity of potpourri is shown in Figure 11.As shown in the figure, for ξ _GasConvergence zero, pseudodensity convergence 1-3 Γ, that is, and the density of the aerating mixture of the low report of this meter (under report) 2 Γ.Yet, work as ζ _GasDuring increase, pseudodensity approaches the fluid density of the reality of 1-Γ.

Compressible influence is shown in Figure 12, and on figure, the density of the observation of model prediction is shown as the only function of the gas volume branch rate of different a series of meters on the natural frequency of pipe.As shown in the figure, the natural frequency of the pipe of the frequency of operation influence that mainly is subjected to reducing under given air-fill levels can influence the relation between density reality and apparent of aerated fluid significantly.

Experimental data

As shown in figure 13, facility is built into the performance of sample plot estimation coriolis meter to the water of inflation.This facility uses the gas volume branch rate that the mag meter of single-phase water operation is monitored aerating mixture as reference flow rate and use based on the table 100 of sonar.

The density of the liquid component of aerated liquid (being water) is assumed to be constant.Several coriolis meters of various designs and manufacturing are tested.Figure 14 shows the pseudodensity of being measured by the coriolis meter of 1 inch diameter pipe of the mesomerism frequency with 100Hz.Data are being recorded from 100 to 200gpm flow rate and 16 to 26psi Coriolis inlet pressure scope.The theoretic correct density that has shown the aerating mixture density factor of 1-Γ is as the result who obtains from the non-glutinousness bubble of the quasi-steady of 1-3 Γ theory.Also shown to have and be tuned to 0.02 ζ _GasThe density factor that produces of lumped parameter.As shown in the figure, the pseudodensity of coriolis meter is a height correlation with the gas volume branch rate of being measured by GVF meter 100.Lumped parameter model appears also to catch this trend.

Figure 15 shows the pseudodensity of being measured by the coriolis meter of 1 inch diameter pipe of the mesomerism frequency with about 300Hz.Data are recorded on flow rate similar to last meter and inlet pressure scope.Again, shown the theoretic correct density of the aerating mixture density factor of 1-Γ, as the result who obtains from the non-viscous bubble of the quasi-steady of 1-3 Γ theory.Also shown have by rule of thumb be tuned to 0.007 ζ _GasThe density factor that produces of lumped parameter.As other tested meter, the pseudodensity of coriolis meter 16 is a height correlation with the gas volume branch rate of being measured by GVF meter 100.Provide in the output of lumped parameter model and the correlativity between the densitometric output and to be used to assess the useful framework of inflation the influence of the pseudodensity of process fluid 12.

Be presented at the performance of the Coriolis density measure that has the speed of sound enhancing of operating under the conditions of air of carrying secretly on Figure 16.Data presentation densitometer betwixt stands the time history of the fluid density of pseudodensity during cycles variable quantity influence, approximate 50 minutes of scope from 0 to 3% of entrapped air, entrapped air and correction.The data that Figure 15 provides are to be used for together quantizing during transition in the fluid density of reality and the difference between the apparent fluid density in conjunction with entrapped air measurement in real time.As shown in the figure, the precision of the fluid density of the meter report that is strengthened by speed of sound is improved widely and is better than pseudodensity by the output of baseline table.

Experimental data and analysis result show that the gas carried secretly is for the significant impact based on the precision of the density measure of vibrating tube.Provide analytical model, the fluid compressibility that illustration increases and heteropical influence can be how be introduced significant error in the density of the decipher of process fluid.How the influence of analytical model illustration inflation is linked with the gas volume branch rate of process fluid, the frequency that reduces and other parameter of vibrating tube.Though illustration analytical model, the present invention imagination: empirical model can be used for compensating or improving the density and/or the mass flowrate of coriolis meter 16.

The experimental data that provides shows: use the real-time measurement advantages associated of gas volume branch rate that the densitometer 16 based on vibrating tube carries out and the frequency that reduces can how to improve the precision of measurement of the unaerated liquid part of aerating mixture density measure and potpourri greatly with combination.

Mass flow corrections

Current prior art level appears to utilize the quasi-steady model and according to the experience correlation of quasi-steady model, amount of measuring and the fluid parameter that obtains is interrelated.This quasi-steady model that is used for the fluidic structures interaction appears to be applicable to the most of coriolis meters to most of industrial process flow operations.The validity of quasi-steady hypothesis will be with the frequency that reduces of the vibration of pipeline inner fluid convergent-divergent.Under the quasi-steady framework, the frequency that reduces is many more, and coriolis meter becomes and gets over out of true.

For one of astable influence in the coriolis meter relevant frequency that reduces is the frequency that reduces according to vibration frequency, pipe diameter and process fluid speed of sound:

${\tilde{f}}_D=\frac{\mathrm{fD}}{a_{\mathrm{mix}}}$

Another relevant frequency that reduces is the frequency that reduces according to the total length of coriolis tube:

${\tilde{f}}_L=\frac{\mathrm{fL}}{a_{\mathrm{mix}}}$

Should be pointed out that for geometry wherein be given meter design that fix, any, two frequencies that reduce are not independently, and are mutually scalar multiple (scalar multiple).For given meter, more than variation in the frequency that reduces mainly determine by the variation in the process fluid speed of sound.

Physically, the frequency representative that reduces is passed through needed time of characteristic length and the ratio of tube vibration between one all needed time at sound transmission.It seems that from performance and precision aspect the frequency that reduces is used for catching the importance of instability in the aeroelasticity interaction of fluid and structure.

Under the restriction of the frequency approach that reduces zero, processing procedure can be modeled as metastable.Most of analytical models of coriolis flowmeter are used for fluid/structure interaction with the quasi-steady model.Yet, for the frequency that reduces of non-zero, astable effect begins to influence the relation between the measured structural response phase lag and the natural frequency of two leg places of meter (promptly) and the fluid parameter (being the mass rate and the fluid density of fluid) sought.

Yet content disclosed herein is to use the gas volume branch rate parameter based on speed of sound, the frequency parameter that reduce relevant with the phase lag of mass flowrate.

If the frequency that reduces based on diameter be can not ignore, then the mass load to pipeline from fluid forms the slight phase lag that increases with the frequency that increases.For the frequency that reduces of can not ignore according to the length that flows pipe, the vibration in the flow velocity degree can change with duct length, introduces the error in the meter output potentially.

From the viewpoint of measures of dimension, 1 inch diameter coriolis meter stream pipe is driven with the peak swing of about 80Hz, 1.5mm.For the purpose of illustrating, the length of stream pipe is estimated as about 1 meter.By using these numerals, for scope from 1500m/s (process liquids is typical) and 50m/s (for the bubble potpourri may) the potpourri speed of sound, be shown in Figure 17 based on the frequency that reduces of diameter and length.

As shown in the figure, because the marked change in the frequency that the typical change of the potpourri speed of sound that two-phase flow causes causes reducing.

Therefore, by dynamically reducing the potpourri speed of sound, gas is incorporated into the frequency that reduces that liquid mixture can reduce the principal oscillation relevant with coriolis meter widely.If do not consider when decipher, this increase in the frequency that then reduces can make the quasi-steady model increase inexactness, and causes the error in mass rate and the density.

Because introducing bubble fluid this reducing that cause, the coriolis meter precision is put down in writing on document well.In fact, other people attempts by gas volume branch rate in the error of the observation in the mass rate and the process fluid is carried out relevant influence of proofreading and correct entrapped air.These authors propose the following correction according to GVF.

$R=\frac{2\mathrm{\&alpha;}}{1-\mathrm{\&alpha;}}$

Wherein α represent gas volume branch rate and R representative by by real mass rate by reducing in (apparent) mass rate of normalized measurement.Therefore, this relevant by using, that carries secretly airborne 1% increases about 2% underestimate that will cause the actual mass flow.

Though this formula has appeared to catch total trend of experimental observation, its use in this field has two shortcomings.At first, coriolis meter 16 does not have the direct mode of measurement gas volume fraction.Suppose to use the pseudodensity of the measurement of fluid to estimate the level of entrapped air, yet because two fundamental measurements, phase differential and natural frequency all are subjected to the change influence of the frequency that reduces of Coriolis vibration, so this is debatable.The second, gas volume branch rate is not the unique variable that influences the natural frequency and the relation between the density of measure phase difference and mass rate and measurement mostly.Though it is relevant on certain scope of parameter at least that gas volume branch rate appears, the physical phenomenon of problem shows indirectly: speed of sound also can have direct influence to decipher via the frequency influence that reduces, and shows as above.

What proposed in this disclosure is to use the decipher of helping coriolis meter 16 from the direct voice measurement of process fluid.In this decipher, the frequency parameter that reduces of Xing Chenging is included in the decipher of phase differential in the vibrating tube and the relation between the mass rate here, and aspect process fluid density, directly effect in the natural frequency of decipher oscillatory flow tubular.The speed of sound measurement combined with the knowledge of process liquids and gas composition and process temperature and pressure also enables directly to measure the air of carrying secretly.Therefore, frequency parameter that reduces and gas volume fraction can be used for as aspect mass rate, the input when decipher phase lag.

Because strong relation between liquid hollow gas content and potpourri speed of sound, the effect of the frequency parameter that reduces as a result the time at the fundamental measurement of decipher coriolis meter will have more outstanding effect in flow of bubble.Yet, various liquid and other handle speed of sound in potpourri and from but change the frequency that reduces of operation also for the decipher of the coriolis meter that uses in using at these and be that precision is influential therefore.Consider the example of stream, coriolis meter is to two kinds of liquid--water and oil-performance.Suppose that fluid has different density and speed of sound.Different fluid behaviour suggestion coriolis meters will be operated in the different frequencies that reduces.The frequency that reduces that is used for water typically will be than being used for the frequency that reduces low about 10% to 30% that oil is used.

Recognize this point, though that is: they are different, being used for the frequency that the speed of sound of two kinds of application reduces still is " little ", and then the influence to precision may be unessential.Yet inexactness is to a certain degree introduced by the difference in the frequency that reduces of the operation of not considering coriolis meter in this application.

Key concept disclosed herein is shown in the water and air loop under near environmental pressure and temperature.The experiment assembling is shown in Figure 13.

In this facility, water is counted by mag by pumping from the bottom of big separation vessel, and it measures the volume flow rate of water.Then, water flows through SONARtrac entrapped air meter, so that the checking glassware for drinking water has the insignificant air of carrying secretly.Air is injected in the water then, forms biphasic mixture.Follow the amount of the air of carrying secretly with the 2nd SONARtrac instrumentation amount.The biphasic mixture of known water and air component is then by 3 inches bend pipe coriolis meters.The output s of all above-mentioned metering outfits wherein is recorded together with water pressure and temperature.By using this information, conduct that the error relevant with the coriolis meter in being operated in aerated liquid can be determined and quilt is drawn is based on the function of the parameter of speed of sound.In this example, the coriolis meter performance is characterized as being the function of gas volume branch rate.Error in the mixture density of mass rate, mixture density and observation is shown in Figure 18.

As shown in the figure, error is significant really.When 2% entrapped air, the mass rate of the excessive report 15% of coriolis meter and owe to report 2% mixture density.By this density of counting the reality of report,, general 4% error will be arranged then if be interpreted as the density of the liquid phase place in this meter.

For this example, the gas volume based on speed of sound of mass rate error by the speed of sound entrapped air divides rate and by parametrization.This parameter dependence is provided by the formula that shows on the curve map.

Quality factor=0.0147gvf^3-0.0018gvf^2+0.0041gvf+1.0009

This relevant being used in then proofreaied and correct the coriolis meter mass rate under the condition that has entrapped air.The time series of Figure 19 video data, wherein the amount of the upstream of the entrapped air of coriolis meter injection changes with little increment, like this, the scope of the level of total entrapped air from 0 to 2%.As shown in the figure, coriolis meter registration and because the appreciable error (up to 15%) in the mass rate that entrapped air causes, in order to illustrate, adopted based on gas volume branch rate relevant successfully with mass rate error correction in general 1%.

Figure 20 shows as that describe, Fig. 2 in the past here gas volume divides rate meter 100.GVF meter 100 comprises sensing device 116 and the processing unit 124 that is disposed on the pipeline 14.Sensing device 116 comprises the array based on the sensor of strain or pressure transducer 118-121, is used to measure by by flowing the 12 astable pressure of propagating that sound wave produced, to determine speed of sound (SOS).Pressure signal P ₁(t)-P _N(t) be provided to processing unit 124, it makes pressure signal digitizing and calculate SOS and the GVF parameter.Cable 113 is connected to processing unit 124 electronically to sensing device 116.Analog pressure sensor signal P ₁(t)-P _N(t) 4-20 milliampere current loop signal typically.

The array of pressure transducer 118-121 comprises along the array of axially isolated two pressure transducers 118,119 of outside surface 122 of the pipeline 14 of wherein propagating process stream 112 at least.Pressure transducer 118-121 can such as bolt, screw and anchor clamps, be releasably attached on the pipeline and be clamped on the pipeline or usually by any securing member of untiing.Alternatively, sensor can for good and all be attached to pipeline 14, be connected with pipeline 14 ports or integrated (for example embedding).The array of the sensor of sensing device 116 can comprise the pressure transducer greater than any number of two sensors, such as 3 between 2 and 24 sensors, 4,8,16 or N sensor.Usually, when the number of sensors in the array increased, measuring accuracy was improved.The degree of accuracy that is provided by the sensor of big figure more is used to calculate the complicacy of output parameter of the stream of wanting and time-related increase and offsets.So the number of employed sensor depends on the degree of accuracy wanted and the renewal rate of wanting of the output parameter that provided by instrument 100 at least.Pressure transducer 118-119 measures by by spreading the astable pressure that the sound wave broadcast produces, and their indications are spread the SOS that broadcasts by fluid in pipeline.Output signal (the P of pressure transducer 118-121 ₁(t)-P _N(t)) be provided to pre-amplifier unit 139, it amplifies the signal that is generated by pressure transducer 118-121.Processing unit 124 processing pressure measurement data P ₁(t)-P _N(t) and determine the parameter of wanting and the characteristic of stream 12, as described previously.

Instrument 100 is also imagined provides one or more sound sources 127, makes the spread speed of sound broadcast of energy measurement by the stream of the peace and quiet on the acoustics for example.Sound source can be an equipment, for example raps on duct wall or vibrates.Sound source can be placed on the input end of sensor 118-121 array or output terminal or at these two ends, as shown in the figure.People should be appreciated that sound source is optional in most of examples, and this instrument does not have the seedbed detection in that the sound ridge (acoustic ridge) that provides in 12 is provided, as what after this describe in more detail.No source noise comprises the noise that is generated by pump, valve, engine and turbulent flow potpourri itself.

As suggestion after this with further describe in more detail, instrument 10 has by measuring by measuring the ability of speed of sound (SOS) by flowing astable pressure that 12 acoustic disturbances of propagating cause.After the pressure of knowing or estimating to flow and/or the speed of sound of temperature and acoustic disturbance or ripple, processing unit 124 can be determined gas volume branch rate, such as what in following patented claim, describe: the U.S. Patent application No.10/349 that on January 23rd, 2003 submitted to, 716 (CiDRA file number No.CC-0579), the U.S. Patent application No.10/376 that on February 26th, 2003 submitted to, 427 (CiDRA file number No.CC-0596), the U.S. Patent application No.10/762 that on January 21st, 2004 submitted to, 410 (CiDRA file number No.CC-0703), these patented claims all are being hereby incorporated by reference.

Be similar to the instrument 100 of Figure 20, implementing instrument 200 of the present invention has along pipeline 14 and axially is placed on two position x1, at least two pressure transducers 118 at x2 place, 119 array, be used for sensing and be in pipeline inherence each random signal their each position, that between sensor 118,119, propagate.Each sensor 118,119 provide indication each sensing station place, at the signal of each astable pressure of locating constantly of a series of sampling instants.It will be understood that sensor array can comprise plural pressure transducer, as at position x ₃, x _NThe pressure transducer 120,121 at place shows.Can be by the pressure that the acoustic pressure disturbance generates by measured based on the sensor and/or the pressure transducer 118-121 of strain.Pressure transducer 118-121 is simulated pressure time varying signal P ₁(t), P ₂(t), P ₃(t), P _N(t) be provided to signal processing unit 124.Processing unit 124 processing pressure signals at first provide the output signal 151,155 of indication by the speed of sound of stream 12 propagation, subsequently, and in response to providing GVF to measure by the pressure disturbance that generates by the sound waves that flow 12 propagation.

The pressure signal that processing unit 124 receives from the array of sensor 118-121.Data capture unit 154 is for the pressure signal P relevant with the sound wave propagated by pipeline 114 14 ₁(t)-P _N(t) carry out digitizing.FFT logical one 56 calculates digitized time-based input signal P ₁(t)-P _N(t) Fourier Tranform, and plural frequency domain (or based on frequency) the signal P of the frequency content of indication input signal is provided ₁(ω), P ₂(ω), P ₃(ω), P _N(ω).

Data accumulator 158 accumulations are from the additional signal P of sensor ₁(t)-P _N(t), and the data of accumulating are provided to array processor 160 on sampling interval, it carries out space-time (two dimension) conversion of sensor signal, from the xt territory to k-ω territory, calculate the power on k-ω plane then, as by k-ω curve map representative, being similar to is provided by this convection current (convective) array processor 146.

In order to calculate the power on k-ω plane, as what represent by the k-ω curve (seeing Figure 22) of signal or differential signal, array processor 160 is determined wavelength and is therefore determined (space) wave number k, and each (time) frequency and angular frequency of also having each spectrum component of stray parameter.A plurality of available algorithms are arranged in PD, and the space/time that is used for carrying out the array of sensor unit 118-121 decomposes.

Exist under the situation of suitable sound wave at two direction of principal axis, determine like this, will be presented on the left side of curve map and the right plane at the power on the k-ω plane that shows on the k-of Figure 22 ω curve map and be called as ridge 170,172 structure, the speed of the sound that one of them ridge 170 indication is advanced along a direction of principal axis, and the speed of the sound that 172 indications of another ridge are advanced along another direction of principal axis.Sound ridge representative is by spreading the concentration degree of the stray parameter broadcast, and is the mathematics form of expression above-mentioned, the relational expression between spatial variations and time variation.The such trend of curve map indication k-ω to more or less occurring along straight line 170,172 with certain slope, slope indication speed of sound.

Determine like this, the power on k-ω plane is provided to ridge recognizer 162 then, its uses one or another feature extraction method to determine the position and the orientation (slope) of any ridge existing on a left side and right k-ω plane.Speed can pass through to use the slope of one of two sound ridges 170,172, or is determined by the slope of average sound ridge 170,172.

At last, the analyzed device 164 of information that comprises ridge orientation (slope) makes and is used for determining and the relevant stream parameter of measuring of speed of sound, such as the gas volume branch rate of the air/mass ratio of the average-size of particle in the density of the consistance of stream or combination, stream, the stream, stream, stream, by spreading the percentage of the interior entrapped air of the speed of sound broadcast and/or stream.

Array processor 160 is used so-called beam shaping, ARRAY PROCESSING or the adaptive array Processing Algorithm of standards, promptly is used for by using various time-delays and weighting that suitable phase relation between the signal that is provided by different sensors is provided, and the algorithm of processes sensor signal, it is functional to create phased array antenna thus.In other words, wave beam formation or ARRAY PROCESSING algorithm are the room and time frequency component that is transformed into them from the time-domain signal of sensor array, promptly be transformed into the one group of wave number that provides by k=2 π/λ, wherein λ is the wavelength of spectrum component, and by corresponding angular frequency that ω=2 π ν provide.

Determine to be to use the ARRAY PROCESSING technology to be defined in sound ridge on the k-ω plane, as shown in figure 22 by the such technology that flows 12 speed of sound of propagating.The speed of sound that the slope indication of sound ridge is propagated in stream 12.Speed of sound (SOS) is to determine that by using the sonar array treatment technology one dimension sonic propagation is determined through the used speed of astable tonometric axial array that distributes along pipeline 14.

Instrument 200 of the present invention is measured potpourri is determined in propagation by the speed of sound (SOS) of the one dimension sound wave of potpourri gas volume branch rate.As everyone knows, sound is propagated by various medium with different speed in such as the such field of sonar and field of radar.Propagation can be determined such as known technology that set forth in following patented claim, a plurality of by using by the speed of the sound of pipeline and stream 12: the U.S. Patent Application Serial Number No.09/344 that on June 25th, 1999 submitted to, 094, be US 6,354 now, 147; The U.S. Patent Application Serial Number No.10/795 that on March 4th, 2004 submitted to, 111; The U.S. Patent Application Serial Number No.09/997 that submit to November 28 calendar year 2001,221, be US 6,587 now, 798; The U.S. Patent Application Serial Number No.10/007 that submit to November 7 calendar year 2001,749; And the U.S. Patent Application Serial Number No.10/762 of submission on January 21st, 2004,410, each all is being hereby incorporated by reference these patented claims.

Measure the flowmeter based on sonar of the sound wave speed of in potpourri, propagating though shown the array that uses sensor 118-121, but it will be appreciated that any means that are used to measure the speed of sound of sound wave all can be used for determining the gas volume branch rate of carrying secretly of potpourri/fluid or other characteristic of the stream described in the past.

The analyzer 164 of processing unit 124 provides the output signal of the characteristic of the indication process stream 12 relevant with the speed of sound (SOS) of propagating the measurement of passing through stream 12.For example, in order to determine gas volume branch rate (or phase place is divided rate), analyzer 164 hypothesis are for the condition near isothermal of stream 12.Like this, gas volume branch rate or voidage interrelate by following quadratic equation and speed of sound:

Ax ²+Bx+C＝0

Wherein x is a speed of sound, A=1+rg/rl* (K _Eff/ P-1)-K _Eff/ P, B=K _Eff/ P-2+rg/rl; C=1-K _Eff/ rl*a _Meas^2); The Rg=gas density, rl=fluid density, K _Eff=effective K (mould of liquid and duct wall), P=pressure, and a _MeasThe speed of sound of=measurement.

In fact,

Gas volume divides rate (GVF)=(B+sqrt (B^2-4*A*C) /) (2*A)

Alternatively, the speed of sound of potpourri can be divided rate (φ with the volume phase of component by the Wood equation _i) and the speed of sound (a) and the density (ρ) of component interrelate.

$\frac{1}{{\mathrm{\&rho;}}_{\mathrm{mix}}{a}_{{\mathrm{mix}}_{\&infin;}}^2}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{{\mathrm{\&phi;}}_i}{{\mathrm{\&rho;}}_i{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="A20048002650800362.png,A20048002650800421.png"\; state="\{\{state\}\}">i</figure-callout>}}^2},$ Here ${\mathrm{\&rho;}}_{\mathrm{mix}}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i{\mathrm{\&phi;}}_i$

The one dimension wave of compression of propagating in the stream 12 in being comprised in pipeline 14 adds non-stable internal pressure load on pipeline.Because the speed of the degree of the piping displacement that astable pressure load causes influence compression wave propagation.Infinite domain speed of sound and density at potpourri; The elastic modulus (E) of the cylinder conduit of vacuum backsight (vacuum-backed), thickness (t) and radius (R); And for the effective propagation velocity (a of one dimension compression _Eff) between relation provide by following formula:

$a_{\mathrm{eff}}=\frac{1}{\sqrt{1/a_{{\mathrm{mix}}_{\&infin;}}^2+{\mathrm{\&rho;}}_{\mathrm{mix}}\frac{2R}{\mathrm{Et}}}}\left(\mathrm{eq}1\right)$

Mix compressibility (1/ (the ρ a that in fact rule sets forth potpourri ²)) be that the compressible volume weighting of component is average.For in the typical pressure of paper and pumping industry and the gas/liquid mixture 12 under the temperature, the compressibility of gas phase is the magnitude bigger than the compressibility of liquid approximately.Therefore, the compressibility of gas phase and the density of liquid phase are mainly determined the potpourri speed of sound, like this, must have the good valuation to processing pressure, so that come decipher potpourri speed of sound according to the volume fraction of the gas of carrying secretly.Pressure process is shown in Figure 23 to the influence of the relation between the speed of sound and the air body integration rate of carrying secretly.

In processing unit 24 some or all functions can be implemented with software (use microprocessor or computing machine) and/or firmware, perhaps can implement to carry out function described herein by simulation and/or digital hardware that use has enough storeies, interface and an ability.

Though as Fig. 2, embodiments of the invention shown in 20 and 21 show that the pressure transducer 118-121 that is placed on the pipeline separates with coriolis meter, but the present invention's imagination, GVF meter 100 can be integrated with coriolis meter, and the single instrument shown in Figure 24 and 25 is provided thus.As what show among these figure, pressure transducer 118-121 can be placed on pipe 302 of coriolis meter 300,310 one or both of.

With reference to Figure 24, two-tube 302 coriolis meters 300 are provided, it has the pressure transducer 118-121 on the pipe 302 that is placed on coriolis meter, the array of 318-320.In the present embodiment, the array of piezoelectric tape 50 is placed on online and is clamped on the pipe 302 as unitary package.This similar is in the U.S. Patent Application Serial Number No.10/795 that submits on March 4th, 2004, describes in 111, and this patented claim is being hereby incorporated by reference.Describe before being similar to here, pressure signal is provided to processing unit with at least one in the frequency of calculating SOS, GVF and reducing.

Figure 25 show pressure transducer 118-121 be integrated in the coriolis meter 310, an alternative embodiment of the invention.Have manyly with advantages associated in the existing areal coverage that sonar array is integrated into coriolis meter, and comprise cost advantage, marketing advantage and potential feature performance benefit.

The stream pipe 302 that adopts in coriolis meter has many and changes.Typically, stream is by the center line call away to from the pipeline that adheres to coriolis meter, yet, also can introduce the coriolis meter that adopts the straight tube consistent with the processing pipeline.The most general type is a U tube coriodis meter as shown in figure 25.No matter the shape that changes is how, Coriolis stream pipe long typically and relative thinner, bending or straight.For the bend pipe coriolis meter, stream pipe typically has constant and than the sectional area that the pipeline 14 that adheres to this meter reduces, and causes leading to the fluid velocity of the increase of flow tube.These two characteristics make the stream pipe be well suited for as the acoustic duct that is used for low-frequency sound wave.

The all-bottom sound waveguide relates to wavelength significantly greater than the ripple of the diameter of stream pipe 302.To see that as us for coriolis meter stream pipe, typically diameter is 1 inch magnitude, this low frequency definition is not strict.Therefore, for 1 inch diameter of transporting water stream pipe, have and be markedly inferior to 60, the sound wave of the frequency of 000Hz is considered to low frequency (1 inch * (1 foot/12 inches) * 5000 feet per seconds).

For these low frequency waves, the bending of Coriolis stream pipe 302 does not have very big influence for sonic propagation speed.Therefore, Coriolis stream pipe 302 is well suited for and is used as the waveguide of sensor array that its deploy is used for determining the gas volume branch rate speed of sound of potpourri.

That most of coriolis meters have is highly tuning, the stream pipe group of balance well.Importantly make any influence of dynamic perfromance of sensor convection tube minimize.For U shown in Figure 25 pipe, shown sensor is deployed near the main body 306 of this meter, manages 302 or be cantilever basically here.By light in this position adhesion weight, based on the sensor 118-121 of strain, the dynamic perfromance of stream pipe should not influenced by sensor array basically.And, two sensors 118,119 and 120,121 is placed on end, allow sensor array aperture (aperture) across whole stream pipe.Equip the stream pipe as describing ground here, make the aperture that is comprised in the sensor array in the coriolis meter maximize.Place a plurality of sensors endways, but more isolated relatively sensor causes isolated array heterogeneous.It will be suitable indicating this method with the primary data of such ARRAY PROCESSING.

Though the integrated coriolis meter 300,310th of Figure 24 and 25, U-shaped, the present invention's imagination, this sensor array can be placed in the pipe of straight tube Coriolis meter equally.

For any embodiment described herein, comprise electric strainmeter, optical fiber and/or particularly as the pressure transducer of grid described herein can or guarantee that other the suitable attachment means that suitably contact between sensor and the pipeline is attached by bonding agent, glue, epoxy resin, belt.Sensor alternatively can be via coming removably or for good and all to be attached such as machanical fastener, spring-loaded, clamping, Clamshell device, overlap joint or the such known mechanical technology of other equivalent.Alternatively, the strainmeter that comprises optical fiber and/or grid can be embedded in the compound pipeline complex pipeline.If want, for some application, if wish, then grid can be disassembled from pipeline (strain or on acoustics with pipeline isolation).

Any other strain sensing technology can be used for the variation of strain in the measuring channel, and such as being attached to or being embedded in ducted extremely sensitive piezoelectricity, electronics or electric strainmeter, this also within the scope of the invention.Accelerometer also can be used for measuring astable pressure.In addition, can use other pressure transducer, as what describe in many above-mentioned patents, these patents are being hereby incorporated by reference.

In another embodiment, sensor can comprise press mold (piezofilm) or tape (for example, PVDF), as what at least one above-mentioned patented claim, describe.

Install in the pipe of coriolis meter or integrated four sensors though illustration is presented at, the present invention's imagination has the sensor of any number in this array, as what instruct at least one above-mentioned patented claim.In addition, the present invention imagines sensor array and can be mounted or be integrated into the pipe that has such as the coriolis meter of kink shape, U-shaped (as shown in the figure), straight tube and any other curve shape.

The present invention also imagine the elongation that provides permission in array, to use the sensor of big figure more, non-vibration (vibration) part.

Be used for measuring sound by spreading the speed broadcast though the present invention describes a sensor array, have several other methods to be used in the decipher Coriolis force and by the relation between the mass rate of coriolis meter.

For example, for narrow fluid, ultrasonic device can be used for determining the speed of sound of the fluid that enters.Should be pointed out that theoretical indication, if the speed of sound of process fluid is measured and be used in decipher, then the decipher of coriolis meter will all be improved for all fluids.Therefore, the speed of sound of knowing fluid is 5000 feet per seconds, as the material of similar water, compare with 1500 feet per seconds, as for example, the postcritical ethene, with the performance of improving based on the stream and the density measure of Coriolis.These measurements can be performed practically by using existing ultrasonic meter.

Another method of determining the speed of sound of fluid is to measure the resonant frequency of the acoustic pattern of stream pipe.In the time of in being installed in streamline, change the very big change that causes acoustic impedance with the sectional area relevant from pipeline to the transition of typically much smaller stream pipe.Because the result of this change of impedance, the stream pipe is equivalent to resonant cavity to a certain extent.By following the tracks of the resonant frequency in this chamber, can determine to occupy the speed of sound of the fluid in this chamber.This can carry out by the single pressure sensitive devices that is installed in coriolis meter or is installed in the piping network that is attached to coriolis meter.

Aspect more generally, the present invention's imagination are used to measure any method of gas volume branch rate of fluid stream or the ability that device increases the performance of expansion coriolis meter by use.

In one embodiment of the present of invention as shown in figure 20, each pressure transducer 118-121 can comprise piezoelectric film sensor, measures the astable pressure of fluid stream 12 by each technology of describing before using here.

Piezoelectric film sensor comprises piezoelectric or film, is proportional to material by mechanically deform or be subjected to the electric signal of the degree of stress with generation.Piezoelectric sensor typically adapts to allow the induction strain, complete or approaching environment measurement completely, so that circumferentially average pressure signal is provided.Sensor can form from PVDM film, co-polymer membrane or flexible PZT sensor, be similar to by Measurement Specialisties, Inc. describe in " Piezo Film Sensors TechnicalManual (the press mold sensor technology handbook) " that provides, this handbook is being hereby incorporated by reference.Can be used in piezoelectric film sensor of the present invention is by Measurement Specialisties, Inc. makes, Part No. 1-1002405-0, LDT4-028K.

Piezoelectric membrane (" press mold ") as piezoelectric, is the dynamic state material that forms the electric charge of the change that is proportional to mechanical stress.Therefore, piezoelectric is measured in pipeline 14 owing to handling the strain that astable pressure variation (for example sound wave) is responded in the potpourri 12.Transducing becomes output voltage or electric current by the piezoelectric sensor that adheres in strain in pipeline.Piezoelectric or film can be formed by fluoropolymer, the such polymkeric substance of Kynoar (PVDF) such as polarization.Piezoelectric film sensor is similar at U.S. Patent Application Serial Number No.10/712,818 (CiDRA file number No.CC-0675), U.S. Patent Application Serial Number No.10/712,833 (CiDRA file number No.CC-0676), with U.S. Patent Application Serial Number No.10/795, the sensor of describing among 111 (the CiDRA file number No.CC-0732), these patented claims all are being hereby incorporated by reference.

An alternative embodiment of the invention comprises that it is mounted on tape so that pressure transducer can be clamped on the pipeline such as pipeline strain sensor, accelerometer, speed pickup or displacement transducer pressure transducer such, that discuss in the back.Sensor can be via coming removably or for good and all to be attached such as machanical fastener, spring-loaded, clamping, Clamshell device, belt or the such known mechanical technology of other equivalent.The pressure transducer of these particular types can expect to be used for pipeline 12 to present a certain amount of pipeline compliance.

In axial positions along pipeline 12, replace single-point pressure transducer 118-121, can around being in the circumference of pipeline 12, each axial location use two or more pressure transducers.Given axial positions, can be from the signal of the sensor around the circumference by on average cross section (or circumference) is average, non-stable sound pressure measurement to provide.Also can use the sound pressure sensor and the annular gap of other number.Average a plurality of annular pressure sensor just reduced from disturbance and pipe vibration and with the noise of irrelevant other noise source of the one dimension acoustic pressure wave in the pipeline 12, create the space array of pressure transducer thus, help to characterize the one dimension sound field in the pipeline 12.

The pressure transducer 118-121 of Figure 20 described herein can be any kind, can measuring channel the pressure transducer of non-stable (or ac or dynamic) pressure in 14, such as piezoelectricity, light, capacitive, ohmic (for example resistance bridge), accelerometer (or geophone), velocity measuring device, displacement measuring device or the like.If make the pressure transducer of using up, sensor 118-121 can be based on the pressure transducer of Bragg grating, such as what submit to on September 8th, 1997, exercise question is the U.S. Patent Application Serial Number No.08/925 of " High Sensitivity Fiber Optic Pressure Sensor forUse in Hash Environments (the high sensitivity optical fiber pressure transducer that is used for the Hash environment) ", 598, be US patent 6 now, 016,702, with exercise question the U.S. Patent Application Serial Number No.10/224 of " Non-Intrusive Fiber Optic Pressure Sensor for MeasuringUnsteady Pressure within a Pipe (the non-intrusion type fibre optic compression sensor of the astable pressure in the measuring channel) ", the sensor of describing in 821, they are being hereby incorporated by reference.In the embodiments of the invention that utilize optical fiber as pressure transducer 14, they can connect individually maybe can be by using wavelength-division multiplex (WDM), Time Division Multiplexing or any other recovery usefulness technology technology along one or more optical fiber by multiple connection together.

In certain embodiments of the present invention, piezoelectron (piezo-electronic) pressure transducer can be used as one or more pressure transducer 115-118, it can be by the stress level in the measuring tube measuring channel or manage non-stable in 14 (or dynamically or ac) pressure and change.These sensors can make directly to contact with potpourri 12 in the butt joint of pipeline inner port.In an embodiment of the present invention, sensor 14 comprises the pressure transducer of being made by PCB Piezotronics.Integrated circuit piezoelectric voltage pattern-type sensor is arranged in a pressure transducer, it is characterized by built-in microelectronics amplifier, and it becomes low-impedance voltage output to the high impedance charge-voltage converting.Particularly, use the Model 106B that is made by PCB Piezotronics, it is the integrated circuit quartz pressure sensor of high sensitivity, acceleration compensation, is suitable for measuring the low-pressure acoustic phenomenon in hydraulic pressure and the pneumatic system.It has measurement ability less than the uniqueness of the little pressure change of 0.001psi under high static condition.106B has the resolution of 300mV/psi sensitivity and 91dB (0.0001psi).

Pressure transducer is incorporated a built-in MOSFET microelectronics amplifier into high impedance electric charge output transform is become voltage signal in low impedance.Sensor is by constant current source power supply, and can work on long coaxial or flat cable and do not have degradation of signals.Voltage signal in low impedance is not subjected to the cable noise or the insulation resistance-degradation pollution effect of triboelectricity.The form that is used for making the power supply of integrated circuit piezoelectric sensor operation to get low cost, 24 to 27 volts, 2 to 20 milliamperes constant current sources usually.Data capture system of the present invention can be incorporated constant current source into, is used for directly powering to the integrated circuit piezoelectric sensor.

Most of piezo-electric pressure sensors are by the compact model quartz crystal that is loaded in advance in the outer rigid housing, or unconfined tourmaline crystal constitutes.The resonant frequency of sensor with microsecond response time and hundreds of kHz given in these designs, has minimum overshoot or damped oscillation.Little diaphragm diameter guarantees the spatial resolution of narrow shock wave.

The output characteristics of piezoelectric pressure sensor systems is the output characteristics of the system of AC-coupling, the signal decay of Chong Fuing wherein, until more than original baseline with below equal area is arranged till.When the amplification level of the incident that monitors rose and fell, output kept around baseline and stabilization, makes the positive and negative area of curve keep equating.

Any strain sensing technology can be used for the variation of strain in the measuring channel, such as the high sensitivity piezoelectricity that is attached to pipeline 12, electronics or electricity, strainmeter and piezoresistive strain instrument, this also is within the scope of the invention.Other strainmeter comprises the resistive paper tinsel type instrument with runway configuration, be similar to submit on June 25th, 1999, U.S. Patent Application Serial Number No.09/344,094, be US 6 now, disclosed sensor in 354,147, this patented claim is being hereby incorporated by reference.The present invention also imagine near the predetermined portions of the circumference that is disposed in pipeline 12 strainmeter.The axial placement of strain transducer and the distance of separation Δ X between strain transducer ₁, Δ X ₂Be determined as described above.

Any other strain sensing technology can be used for the variation of strain in the measuring tube, and such as the strainmeter that is attached to or is embedded in high sensitivity piezoelectricity, electronics or electricity in the pipe 14, this also is within the scope of the invention.

Though described a plurality of sensors, it will be appreciated that any sensor that is used for measuring the speed of the sound of propagating by fluid can be used in the present invention, comprises sonac.

The yardstick of any embodiment described herein and/or geometry only are used for illustrative purposes, like this, it seems, if want from the instruction here, can require or other factors according to application, size, performance, manufacturing, use any other yardstick and/or geometry.

Should see that unless narration in addition, any characteristic, feature, alternative or the amendment scheme described about the specific embodiment here also can be applied to, be used in or merge with any other embodiment described herein.And the accompanying drawing here neither be drawn in proportion.

Though the present invention describes for its exemplary embodiment and shows, can be under the conditions without departing from the spirit and scope of the present invention make above-mentioned and various other interpolations and omission therein and to it.

Claims (8)

1. flow measuring system that is used for measuring the density of the fluid that flows at pipeline, this measuring system comprises:

Coriolis meter, it has at least one pipe that wherein has fluid to flow through, and coriolis meter provides the frequency signal of the natural frequency of indicating this pipe and/or the phase signal of the phase differential of indication between pair of pipes;

Flow measurement device, it measures the speed that sound is propagated by this fluid, and this measuring equipment provides at least one in following: the GVF signal of the SOS signal of the speed that indication sound is propagated by fluid, the gas volume branch rate of indication fluid and the frequency that reduces of indication fluid reduce frequency; And

Processing unit, it is according at least one the measurement of mass flow rate of determining compensation in SOS signal, GVF signal and frequency signal that reduces and the phase signal, and/or determines the density measure that compensates according at least one in SOS signal, GVF signal and the frequency signal that reduces and this frequency signal.

2. the measuring system of claim 1, wherein the speed of sound measurement is used for determining the gas volume branch rate (GVF) in the stream of fluid.

3. the measuring system of claim 1, wherein coriolis meter comprises at least one pipe, its have be arranged thereon, be used for the fluid that flows is therein carried out speed of sound measured sensor array.

4. the measuring system of claim 3, wherein sensor array comprises the sensor based on strain.

5. the measuring system of claim 1, wherein coriolis meter comprises a pipe, its have be arranged thereon, be used for the fluid that flows is therein carried out the speed of sound sensing equipment that speed of sound is measured.

6. the measuring system of claim 1, wherein coriolis meter comprise be arranged on the pipeline, be used for the fluid that flows is therein carried out the speed of sound sensing equipment that speed of sound is measured.

7. the measuring equipment of claim 1, wherein the pipe of coriolis meter is crooked or straight.

8. the measuring equipment of claim 1, wherein processing unit is determined the composite signal of density of the on-inflatable part of indication fluid according to the density measure of SOS signal and compensation.

Images