CN202209964U - Flow velocity and flow rate measuring device for fluid - Google Patents

Abstract

The utility model discloses a flow velocity and flow rate measuring device for a fluid. The flow velocity and flow rate measuring device for the fluid comprises an AC (alternating current) exciting source, a three-electrode non-contact conductive sensor, a both end grounding structure, a signal processing module, a data acquisition module and a microcomputer. In the flow velocity and flow rate measuring device for the fluid, a non-contact conductive measurement technology is used for measuring the flow velocity and the flow rate of the fluid. Two groups of independent conductive signals are acquired by the three-electrode non-contact conductive sensor and are processed by a related technology to acquire the flow velocity and the flow rate of the fluid. Adverse influence of coupling capacitance on measurement range and sensitivity is effectively eliminated by a series resonance method. The both end grounding structure eliminates the adverse influence of floating voltage at both ends of a pipeline on measurement accuracy and facilitates connecting insulation measuring pipelines with industrial field metal pipelines. The corresponding device has the advantages of a simple structure, low cost, no contact, no pressure loss, wide application range and the like and provides an effective method for measuring the flow velocity and the flow rate of the fluid in the pipeline.

Description

A kind of rate of flow of fluid flow measurement device

Technical field

The utility model relates to rate of flow of fluid flow detection technology, relates in particular to a kind of rate of flow of fluid flow measurement device.

Background technology

Ducted fluid extensively is present in industry departments such as petrochemical complex, food pharmaceutical, metallurgy, public work and environmental protection, and the on-line measurement of its flow velocity and flow has great importance for production operation in the industrial processes, reliability service and quality control etc.Existing flow rate measurement instrument is comparatively ripe to flow velocity, the flow measurement technology of pure fluid in the conventional caliber pipeline in the industrial processes; But flow rate problems of measurement for the conducting fluid that has fouling product, suspension and solid impurity etc.; Present research work is also very limited, and relevant measurement means relatively lacks.

The capacity coupling non-contact conductance measuring technique is a kind of novel conductance measurement technology.Because electrode directly do not contact with fluid to be measured, therefore there are not the problems such as galvanic corrosion and electrode polarization effect in traditional contact conductance measurement, have wide industry practice application demand.Yet, at present this Study on Technology with use that the ion concentration of kapillary yardstick and following caliber detects in the fields such as mainly being confined to analytical chemistry, belong to blank basically in the industrial flow velocity of routine, flow measurement field.

The utility model is surveyed rate of flow of fluid, the flow measurement field that the conductance measurement technology is applied to industrial process with the capacitance coupling type noncontact, has designed a kind of rate of flow of fluid, flow measurement device and method.That related device has is simple in structure, noncontact, no pressure loss, cost is low and advantages of wide application range, for measuring channel inner fluid speed flow provides an effective new way.

Summary of the invention

The purpose of the utility model overcomes the deficiency of prior art, and a kind of stable, reliable rate of flow of fluid flow measurement device is provided.

The rate of flow of fluid flow measurement device comprises ac-excited source, the first metal flange web member, first ground wire, the second metal flange web member, second ground wire, signal processing module, data acquisition module, microcomputer, insulation measurement pipeline, first detecting electrode, the first inductance module, the 3rd inductance module, exciting electrode, second detecting electrode, the second inductance module; Constitute three electrode non-contact electric conductivity sensors by insulation measurement pipeline, first detecting electrode, the first inductance module, the 3rd inductance module, exciting electrode, second detecting electrode, the second inductance module; Outer wall at the insulation measurement pipeline equidistantly is equipped with first detecting electrode, exciting electrode and second detecting electrode; Exciting electrode links to each other with the 3rd inductance module one end; First detecting electrode links to each other with the first inductance module, one end; Second detecting electrode links to each other with the second inductance module, one end; The 3rd inductance module other end links to each other with ac-excited source; The first inductance module other end links to each other with signal processing module, data acquisition module, microcomputer in order; The second inductance module other end links to each other with signal processing module, data acquisition module, microcomputer in order; Insulation measurement pipeline one end is provided with the first metal flange web member and constitutes a ground structure through first ground connection, and the insulation measurement pipeline other end is provided with the second metal flange web member and constitutes another ground structure through second ground connection.

The utility model compared with prior art has beneficial effect:

1) metering system is contactless, not only can not influence the distribution of measured medium flow characteristics, fluid field of flow, also can not bring the pressure loss.The non-contact measurement mode is not only applicable to measure pure single-phase conductive fluid, also is applicable to measure the conducting fluid that contains fouling product, suspension and solid impurity etc., and problems such as obstruction take place measuring channel easily when especially having solved this type of fluid of measurement;

2) adverse effect of coupling capacitance to measurement range and measuring accuracy eliminated in the application of series resonance method, enlarged the line size that measurement mechanism is suitable for.Simultaneously, in the utility model three groups independently the inductance module cancel out each other with three groups of coupling capacitances respectively, realized between upstream sensor and the downstream sensor separately, make sensor construction be simple and easy to realize;

3) application through the two-terminal-grounding structure; Not only eliminated the insulation measurement pipe ends adverse effect of voltage of floating to measuring accuracy; Improved stability, anti-interference and the measuring accuracy of measuring system, can also easily sensor be connected with the commercial production pipeline.

Description of drawings

Fig. 1 is the structural representation of rate of flow of fluid flow measurement device;

Fig. 2 is the three electrode non-contact electric conductivity sensor equivalent circuit diagrams of the utility model;

Fig. 3 is three electrode non-contact electric conductivity sensors equivalent circuit diagram and principle of work synoptic diagram when the series resonance state of the utility model;

Among the figure: ac-excited source 1, the first metal flange web member 2, first ground wire 3, the second metal flange web member 4, first ground wire 5, signal processing module 6, data acquisition module 7, microcomputer 8, insulation measurement pipeline 9, first detecting electrode 10, the first inductance module 11, the 3rd inductance module 12, exciting electrode 13, second detecting electrode 14, the second inductance module 15.

Embodiment

As shown in Figure 1; The rate of flow of fluid flow measurement device comprises ac-excited source 1, the first metal flange web member 2, first ground wire 3, the second metal flange web member 4, second ground wire 5, signal processing module 6, data acquisition module 7, microcomputer 8, insulation measurement pipeline 9, first detecting electrode 10, the first inductance module 11, the 3rd inductance module 12, exciting electrode 13, second detecting electrode 14, the second inductance module 15; Constitute three electrode non-contact electric conductivity sensors by insulation measurement pipeline 9, first detecting electrode 10, the first inductance module 11, the 3rd inductance module 12, exciting electrode 13, second detecting electrode 14, the second inductance module 15; At the outer wall of insulation measurement pipeline 9 first detecting electrode 10, exciting electrode 13 and second detecting electrode 14 are installed equidistantly; Exciting electrode 13 links to each other with the 3rd inductance module 12 1 ends; First detecting electrode 10 links to each other with the first inductance module, 11 1 ends; Second detecting electrode 14 links to each other with the second inductance module, 15 1 ends; The 3rd inductance module 12 other ends link to each other with ac-excited source 1; The first inductance module, 11 other ends link to each other with signal processing module 6, data acquisition module 7, microcomputer 8 in order; The second inductance module, 15 other ends link to each other with signal processing module 6, data acquisition module 7, microcomputer 8 in order; Insulation measurement pipeline 9 one ends are provided with the first metal flange web member 2 and constitute a ground structure through first ground wire, 3 ground connection, and insulation measurement pipeline 9 other ends are provided with the second metal flange web member 4 and constitute another ground structure through second ground wire, 5 ground connection.

Utilize this apparatus and method measurement rate of flow of fluid flow flow process to be: the frequency of ac-excited source 1 output AC pumping signal is a resonance frequency; Ac-excited signal is after-applied to exciting electrode 13 through the 3rd inductance module 12; Directly reflected two groups of independence conductance signals that fluid flows through first detecting electrode 10, the first inductance module 11 and second detecting electrode 14, the second inductance module 15 again; After conductance signal is handled through signal processing module 6, output to through data acquisition module 7 and to carry out computing cross-correlation on the microcomputer 8 and obtain the transit time and further obtain flow velocity and flow.

The step of rate of flow of fluid flow-measuring method is following:

1) the two-terminal-grounding structure has been eliminated the measuring channel two ends adverse effect of voltage to measuring accuracy of floating;

2) as shown in Figure 2; The excitation frequency f that ac-excited source 1 is set is that the resonance frequency of three electrode non-contact electric conductivity sensors is under this frequency excitation signal effect; Conductivity sensor is in resonant condition, the equivalent electrical circuit impedance $Z_s=\frac{A^2(R_1{R}_2+R_1{R}_{x2}+R_2{R}_{x1}+R_{x1}{R}_{x2})+R_1{R}_2{R}_{x1}{R}_{x2}+A(R_1{R}_2{R}_{x1}+R_1{R}_2{R}_{x2}+R_1{R}_{x1}{R}_{x2}+R_2{R}_{x1}{R}_{x2})}{A^2(R_1+R_2+R_{x1}+R_{x2})+R_1{R}_2(R_{x1}+R_{x2})+A(2R_1{R}_2+R_1{R}_{x1}+R_2{R}_{x1}+R_1{R}_{x2}+R_2{R}_{x2})}$ In imaginary part disappeared fully, the equivalent electrical circuit resulting impedance demonstrates pure resistive, wherein, the resonance factor

F is the excitation frequency in ac-excited source 1, and C is first capacitor C in the conductivity sensor equivalent electrical circuit ₀, second capacitor C ₁With the 3rd capacitor C ₂Value and C ₀=C ₁=C ₂=C, L are inductance module first inductance L ₀, second inductance L ₁With the 3rd inductance L ₂Inductance value and L ₀=L ₁=L ₂=L, first capacitor C ₀Be the coupling capacitance that exciting electrode 13, insulation measurement pipeline 9 and pipeline inner fluid form, second capacitor C ₁The coupling capacitance that to be first detecting electrode 10, insulation measurement pipeline 9 form with the pipeline inner fluid, the 3rd capacitor C ₂Be second detecting electrode 14, insulation measurement pipeline 9 and the formed coupling capacitance of pipeline inner fluid, first inductance L ₀Be the 3rd inductance module 12, the second inductance L ₁Be the first inductance module, 11, the three inductance L ₂Be the second inductance module, 15, the first impedance R _X1It is first capacitor C ₀With second capacitor C ₁Fluid equiva lent impedance between the two, the second impedance R _X2It is first capacitor C ₀With the 3rd capacitor C ₂Fluid equiva lent impedance between the two, the 3rd impedance R ₁It is second capacitor C ₁With earth potential fluid equiva lent impedance between the two, the 4th impedance R ₂It is the 3rd capacitor C ₂With earth potential fluid equiva lent impedance between the two;

3) as shown in Figure 3, under resonant condition, second capacitor C ₁The capacitive reactance and second inductance L ₁Induction reactance, the 3rd capacitor C ₂Capacitive reactance and the 3rd inductance L ₂Induction reactance cancel out each other the first impedance R _X1With second capacitor C ₁, the second impedance R _X2With second capacitor C ₂Link directly with signal processing module 6 in the operational amplifier reverse input end link to each other, with earth potentials such as operational amplifier in-phase input end, the first impedance R _X1, the second impedance R _X2The other end links to each other with earth potential, therefore the first impedance R _X1, the second impedance R _X2Two ends are all earth potential by short circuit, do not have electric current from the first impedance R _X1, the second impedance R _X2Process, the then first impedance R _X1, the second impedance R _X2With the voltage isolation of floating of measuring system and pipe ends, the voltage of floating is to not influence of measuring system, first capacitor C simultaneously ₀With first inductance L ₀Cancel out each other; The coupled relation of the downstream electrical derivative sensor of having eliminated the upstream sensor that constitutes by insulation measurement pipeline 9, first detecting electrode 10, the first inductance module 11, the 3rd inductance module 12, exciting electrode 13, having constituted by insulation measurement pipeline 9, the 3rd inductance module 12, exciting electrode 13, second detecting electrode 14, the second inductance module 15, the upper reaches, separate common use first inductance L of downstream electrical derivative sensor ₀As input end, the 3rd impedance R ₁With the 4th impedance R ₂Separate being independent of each other, signal processing module 6 obtains two groups of independently conductance signals through three electrode non-contact electric conductivity sensors;

4) two groups of independence conductance signals of 6 pairs of upper reaches of signal processing module, downstream electrical derivative sensor output amplify, will be collected in the microcomputer 8 by data acquisition module 7 after the rectification, Filtering Processing, adopt following public calculation flow rate and flow, utilize formula

Obtain transit time τ ₀, wherein middle R _Xy(τ) be related coefficient, x (t) works as R for the conductance signal of upstream electrical derivative sensor output, y (t) for the conductance signal of downstream electrical derivative sensor output _XyObtain transit time τ during (τ) for maximal value ₀, and then obtain flow velocity

Flow Q=AV _c, wherein L is the spacing of the upper reaches, downstream electrical derivative sensor, A is the area of section of measuring channel.

Utilized all even non-homogeneous conductive fluid on the horizontal glass pipeline to the utility model in mentioned apparatus and method carried out the feasibility that the utility model has been verified in preliminary test; Wherein horizontal glass pipeline internal diameter is respectively 3.10mm and 4.00mm; External diameter is respectively 4.80mm and 5.10mm; The homogeneous conductive fluid is conventional tap water in the test(ing) medium, and non-homogeneous conductive fluid is the non-homogeneous mixed solution of water and milk.Test findings shows: utilize apparatus and method mentioned in the utility model, can realize flow rate of fluid in the pipeline, flow measurement, and can obtain measurement result preferably.

Claims (1)

1. rate of flow of fluid flow measurement device; It is characterized in that comprising ac-excited source (1), the first metal flange web member (2), first ground wire (3), the second metal flange web member (4), second ground wire (5), signal processing module (6), data acquisition module (7), microcomputer (8), insulation measurement pipeline (9), first detecting electrode (10), the first inductance module (11), the 3rd inductance module (12), exciting electrode (13), second detecting electrode (14), the second inductance module (15); Constitute three electrode non-contact electric conductivity sensors by insulation measurement pipeline (9), first detecting electrode (10), the first inductance module (11), the 3rd inductance module (12), exciting electrode (13), second detecting electrode (14), the second inductance module (15); Outer wall at insulation measurement pipeline (9) equidistantly is equipped with first detecting electrode (10), exciting electrode (13) and second detecting electrode (14); Exciting electrode (13) links to each other with the 3rd inductance module (12) one ends; First detecting electrode (10) links to each other with the first inductance module (11) one ends; Second detecting electrode (14) links to each other with the second inductance module (15) one ends; The 3rd inductance module (12) other end links to each other with ac-excited source (1); First inductance module (11) other end links to each other with signal processing module (6), data acquisition module (7), microcomputer (8) in order; Second inductance module (15) other end links to each other with signal processing module (6), data acquisition module (7), microcomputer (8) in order; Insulation measurement pipeline (9) one ends are provided with the first metal flange web member (2) and constitute a ground structure through first ground wire (3) ground connection, and insulation measurement pipeline (9) other end is provided with the second metal flange web member (4) and constitutes another ground structure through second ground wire (5) ground connection.

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