Method for determining volume fraction of phases of multiphase medium and corresponding measuring device

Abstract

The invention describes and illustrates a method for determining a volume fraction of phases of a multiphase medium having a first phase having a first value of a first electrical parameter and at least temporarily having a second phase having a second value of the first electrical parameter, wherein a plurality of electrical excitation signals are applied to the medium by means of the electrode pairs and a plurality of respective electrical reaction signals are detected for the electrical excitation signals, a plurality of values of a first electrical parameter of the medium are ascertained on the basis of the plurality of excitation signals and the plurality of reaction signals, and a volume fraction of the second phase at the medium is determined, according to the method, discrete values of statistical discrete metrics are obtained according to a plurality of obtained values of a first electrical parameter of a medium; and determining the volume fraction of the second phase in the medium using the ascertained discrete value of the first electrical parameter using a mathematical relationship between the statistical discrete measure of the first electrical parameter and the volume fraction of the second phase in the medium.

Description

Technical Field

[0001] The invention relates to a method for determining the volume fractions of phases of a multiphase medium, wherein the medium has a first phase and at least temporarily a second phase, the first phase having a first value of a first electrical parameter and the second phase having a second value of the first electrical parameter, wherein a plurality of electrical excitation signals are applied to the medium via an electrode pair and a plurality of corresponding electrical reaction signals are detected for the electrical excitation signals, wherein a plurality of values ​​of the first electrical parameter of the medium are determined based on the plurality of excitation signals and the plurality of reaction signals. In addition, the invention relates to a measuring device, which comprises: a measuring volume for accommodating a medium, wherein the medium has a first phase and at least temporarily a second phase, the first phase having a first value of the first electrical parameter and the second phase having the second value of the first electrical parameter; a control and evaluation unit; an electrode pair in contact with the medium, wherein the control and evaluation unit applies a plurality of electrical excitation signals to the medium via the electrode pair in the operating state of the measuring device and a plurality of corresponding electrical reaction signals are detected for the electrical excitation signals, wherein a plurality of values ​​of the first electrical parameter of the medium are determined based on the plurality of excitation signals and the plurality of reaction signals. Background Art

[0002] Methods and measuring devices of the aforementioned type are often used in combination with other measuring methods, such as, for example, in flow measurement. In flow measurement, the volume flow (for example, with a magnetic inductive flow measuring device) or the mass flow (for example, with a Coriolis mass flow measuring device) is also calculated indirectly via the flow velocity of the medium. If it is known that the medium can have multiple phases in the measurement task, it is obvious that not only the volume flow or mass flow of the multiphase medium is of interest, but also the composition of the medium, that is, the proportion of the different phases in the multiphase medium. Here, the term "phase" is therefore not limited to being understood in the sense of the state of aggregation, but can also be understood as a multiphase system. Such multiphase systems are present in many applications in the chemical industry, in oil and gas production, in waste gas treatment, etc.

[0003] The method is implemented with the prerequisite that there are electrodes which are in contact with the medium and by which an electrical excitation signal can be applied to the medium. For example, it is known that a voltage is applied to the medium as an electrical excitation signal and the resulting current is detected as an electrical reaction signal. Thus, the ohmic resistance value or impedance of the medium can be determined as a first electrical parameter of the medium based on the values ​​of the voltage and the current. If it is based on the fact that the first electrical parameter of the first phase in pure form is different from the first electrical parameter of the second phase in pure form, it is obvious that the first electrical parameter of the multiphase medium also changes with the change in the proportion of the first phase and the second phase and the proportion of the second phase (and therefore also the proportion of the first phase) can be determined by the relationship between the first electrical parameter and the known mixing ratio of the material phases. The method is used, for example, in magnetic induction flow measuring devices, which according to principle have electrodes, which are first used to receive the voltage induced in the medium. These statistical dispersion measurement (Streuungsmaβ) electrodes are used in the implementation of the method for determining the volume proportion of the phases in order to apply the electrical excitation signal to the medium.

[0004] The problem with the method described is that the reliability of the result of the determination of the volume fractions of the participating phases depends to a great extent on the fact that only the phases used with known values ​​for the first electrical parameter of the phases participate and that the participating phases of the multiphase medium remain unchanged. It is definitely more often that at least one of the participating phases actually changes in its characteristics (and thus also in the first electrical parameter), as an example of a two-phase medium consisting of oil and seawater, where the salt content (and thus the electrical conductivity) of the seawater changes. Thus, in the method described, the volume fractions of the phases of the medium determined are very sensitive to changes in the participating media. Summary of the invention

[0005] The object of the present invention is therefore to improve a method for determining the volume fractions of phases of a multiphase medium and also a measuring device in such a way that they are less sensitive to changes in the phases involved and in the value of their first electrical parameter.

[0006] The above-mentioned object is achieved in the method for determining the volume fraction of a phase of a multiphase medium described at the beginning and in the measuring device described at the beginning by means of the features of the characterizing part of the independent claims. The method according to the invention is characterized in that discrete values ​​of a statistical dispersion measure are determined based on a plurality of determined values ​​of a first electrical parameter of the medium, and the volume fraction of the second phase in the medium is determined using the determined discrete values ​​of the first electrical parameter while using a mathematical relationship between the statistical dispersion measure of the first electrical parameter and the volume fraction of the second phase in the medium. It is noteworthy for the method that the instantaneous value of the first electrical parameter (such as, for example, the determined medium conductivity or medium impedance) is deviated from and instead a statistical dispersion measure of the first electrical parameter is applied based on a plurality of values ​​of the first electrical parameter. According to the invention, it is known that there is a relationship between the discrete values ​​of the statistical dispersion measure and the volume fraction of the second phase in the medium. The application of this relationship itself already reduces the dependence on the absolute value of the first electrical parameter of the medium.

[0007] According to an advantageous embodiment of the method, the excitation signal is a voltage or a current. Accordingly, the electrical reaction signal is a current or a voltage, in particular wherein the excitation signal is a harmonic vibration with an excitation frequency. The excitation signal is selected as a harmonic vibration to achieve the purpose of controlling the harmonic alternating variable. The first electrical parameter is analyzed and processed.

[0008] According to another advantageous embodiment of the method, it is provided that the application of the electrical excitation signal to the medium is carried out within a time range in which no other measured value detection is carried out in the medium. This measure prevents different measured value detections from influencing each other and thus leading to worse measured value results overall. If the method is carried out in a magnetic-inductive flow measuring device, which, as described above, already has an active relationship with the medium via corresponding electrodes, the method for determining the volume fraction of the phase is then carried out without carrying out a magnetic-inductive flow measurement. In particular, the method is then carried out after the polarity of the magnetic field, which is always required for a magnetic-inductive flow measurement, is switched, in particular within the time range of a non-stationary magnetic field, since this time range is not very suitable for flow measurement.

[0009] In another preferred embodiment of the method, a standard deviation is calculated as a measure of statistical dispersion. The standard deviation is simple to calculate and has been shown to show a good correlation with the volume fraction of the second phase of the medium in many cases.

[0010] Another advantageous development of the method is characterized in that the first electrical parameter of the medium is the conductivity of the medium and / or the magnitude of the medium impedance and / or the phase angle of the medium impedance, in particular wherein the conductivity is determined as a function of the real part of the medium impedance taking into account the geometry of the measurement volume in which the medium is located.

[0011] In a preferred embodiment of the method, a decisive and continuous insensitivity to changes in the material properties of the phases involved and changes in the values ​​of the first electrical parameter of the phases can be achieved by normalizing the determined discrete values ​​of the first electrical parameter to the absolute value of the first electrical parameter, in particular to the absolute mean value of the first electrical parameter calculated from a plurality of determined values ​​of the first electrical parameter of the medium. The standardization also makes the standard deviation independent of the absolute value and possible fluctuations in the absolute value of the first electrical parameter of the phases. Even if the material composition of one or both of the phases involved changes, a good correlation between the change in the determined discrete values ​​of the first electrical parameter and the volume fraction of the second phase of the medium is achieved when using the standardized variable.

[0012] Another preferred development of the method is characterized in that a plurality of values ​​of a second electrical parameter of the medium are ascertained as a function of a plurality of excitation signals and a plurality of response signals; discrete values ​​of a statistical dispersion measure are ascertained as a function of a plurality of ascertained values ​​of the second electrical parameter of the medium; and the volume fraction of the second phase in the medium is determined using the ascertained discrete values ​​of the second electrical parameter using a mathematical relationship between the statistical dispersion measure of the second electrical parameter and the volume fraction of the second phase in the medium. The relationship of the volume fraction of the second phase in the medium (and thus the volume fraction of the first phase in the medium) to the values ​​of the applied statistical dispersion measure of different electrical parameters of the medium has proven to be widely applicable for different electrical parameters, so that further electrical parameters can also be easily used to determine the volume fraction of the second phase of the medium. This results in multiple possibilities for mutual checking of calculation results, i.e. also for redundancy and / or for combining different calculation results by different paths, and also for mutual checkability and for plausibility control of the results obtained by different paths with respect to the volume fraction of the second phase of the medium.

[0013] The above preferred embodiment of the method provides the possibility of improving the method by calculating the average volume fraction of the second phase of the medium from the volume fraction of the second phase of the medium determined using the first electrical parameter of the medium and from the volume fraction of the second phase of the medium determined using the second electrical parameter of the medium. Thus, the possibility of combining volume fractions of the second phase of the medium determined based on different electrical parameters of the medium is provided, since the relationship between the value of the applied statistical dispersion measure of the electrical parameter of the medium and the volume fraction of the second phase of the medium has proven to be relatively general.

[0014] In another advantageous embodiment of the method, the volume fraction of the second phase in the medium calculated using the first electrical parameter of the medium and / or the volume fraction of the second phase in the medium calculated using the second electrical parameter of the medium and / or the average volume fraction of the second phase in the medium are represented by signals, in particular the calculated volume fractions are saved in a memory of a control and analysis unit of the measuring device and / or displayed and / or transmitted to a connected communication partner via a communication interface of a flow measuring device, in particular a magnetic-inductive flow measuring device.

[0015] In another preferred design of the method, it is provided that when the volume share of the second phase in the medium, calculated using the first electrical parameter of the medium, exceeds a first boundary value and / or the volume share of the second phase in the medium, calculated using the second electrical parameter of the medium, exceeds a second boundary value and / or the average volume share of the second phase in the medium exceeds a third boundary value, the presence of a two-phase flow is indicated by a signal, in particular, the signal is saved in a memory of a control and analysis unit of the measuring device and / or displayed and / or transmitted to a connected communication partner via a communication interface of the measuring device, in particular a magnetic-inductive flow measuring device.

[0016] In a preferred embodiment of the method, it is provided that a mathematical relationship between a statistical discrete measure of a first electrical parameter and a volume fraction of a second phase of a medium and / or a mathematical relationship between a statistical discrete measure of a second electrical parameter and a volume fraction of a second phase of a medium is determined by determining discrete values ​​of the first electrical parameter and / or discrete values ​​of the second electrical parameter in the case of at least two different but known volume fractions of the second phase, in particular wherein a linear relationship is adopted between the statistical discrete measure of the first electrical parameter and the volume fraction of the second phase of the medium and / or between the statistical discrete measure of the second electrical parameter and the volume fraction of the second phase of the medium. If there are only two support points, a linear equation can be immediately derived from this as a relationship between the volume fraction of the second phase of the medium and the discrete values ​​of the statistical discrete measure of the second medium. In the case of more than two support points, the relationship can be expressed linearly as a regression line. It has been shown that the adoption of such a linear relationship represents a suitable approximation of the actual behavior.

[0017] In another preferred design of the method, more than two supporting points are used, that is, more than two relationships are used between the statistical discrete measure of the first electrical parameter and the volume fraction of the second phase of the medium; and a polynomial description of the relationship is obtained as a mathematical relationship between the statistical discrete measure of the electrical parameter and the volume fraction of the second phase of the medium, or a description of the relationship is obtained by spline interpolation, in particular when the description of the relationship is optimized by minimizing a deviation measure.

[0018] In the measuring device mentioned at the outset, the derived object is achieved in that the control and evaluation unit is designed in such a way that the measuring device carries out the method described in detail above during operation. In particular, the method is used in flow measuring devices in which the necessary electrodes are already provided, in particular magnetic-inductive flow measuring devices, Coriolis mass flow measuring devices, vortex flow measuring devices, etc. ) in magnetic resonance flow measurement devices or float flow measurement devices In the last-mentioned flow measuring device, the electrodes required for carrying out the method are not necessarily provided, but may have to be provided in addition. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In particular, there are now many possibilities for designing and developing the method according to the invention and the measuring device according to the invention. For this purpose, reference is made on the one hand to the claims following the independent claim and on the other hand to the following description of exemplary embodiments in conjunction with the drawings.

[0020] In the attached figure:

[0021] Figure 1 The basis of a method for determining the volume fractions of phases of a multiphase medium is schematically shown in certain aspects;

[0022] Figure 2 The steps of a method for determining the volume fractions of phases of a multiphase medium are schematically shown;

[0023] Figure 3 A method for determining the volume fractions of phases of a multiphase medium by means of electrical conductivity is schematically shown;

[0024] Figure 4 A method for determining the volume fractions of phases of a multiphase medium by means of electrical impedance is schematically shown;

[0025] Figure 5 A method for determining the volume fractions of phases of a multiphase medium by means of absolute values ​​of electrical impedance is schematically shown;

[0026] Figure 6 A method for determining volume fractions of phases of a multiphase medium using phase information from electrical impedance is schematically shown; and

[0027] Figure 7 A measuring device for determining the volume fractions of phases of a multiphase medium by means of the above-described method is schematically shown. DETAILED DESCRIPTION

[0028] Figures 1 to 7A method 1 and a measuring device 2 for determining the volume fraction V% of a phase of a multiphase medium M are shown in different aspects, wherein the medium M has a first phase P1 with a first value E1 of a first electrical parameter E and at least temporarily a second phase P2 with a second value E2 of the first electrical parameter E.

[0029] In the drawings, not only numbers but also letters are used as reference numerals. Letters mostly have only the characteristics of reference numerals, but they greatly simplify the understanding and establishment of the relationship between the description and the drawings. In part, the reference numerals also have the characteristics of formula symbols, wherein the formula symbols, for example in the claims, are helpful for understanding the claims, but are not essential for understanding the claims. In this regard, letter reference numerals and formula symbols are arranged in brackets in the claims and are also treated like reference numerals in the following description of the drawings.

[0030] The measurements under consideration relate to frequently encountered measurement tasks in which the proportions of different phases P1, P2 in a medium M are of interest. If, for example, the volume flow is measured simultaneously, the information about the phase proportions of the phases P1, P2 in the medium M is decisive for the measurement process, for example for the purpose of accounting for the raw materials provided; this is immediately apparent if, for example, the first phase P1 of the medium M is liquid crude oil and the second phase P2 of the medium M is water ( Figure 7 ).

[0031] exist Figures 1 to 6 While preferring to clarify the characteristics of the method, Figure 7 A measuring device 2 for determining the volume fractions V% of the phases of a multiphase medium M is shown in FIG.

[0032] In order to determine the volume fractions V% of the phases of a multiphase medium M, it is known to apply a plurality of electrical excitation signals to the medium M via the electrode pair 3 and to detect a plurality of corresponding electrical reaction signals for these electrical excitation signals. A plurality of values ​​En of a first electrical parameter E of the medium M are determined as a function of the plurality of excitation signals and the plurality of reaction signals. If the phases P1, P2 in pure form are known phase components P1, P2 with known values ​​of the first electrical parameter E, for example a specific electrical conductivity, it is obvious that a changed fraction of the phases P1, P2 in the medium M also leads to a changed value of the first electrical parameter E of the medium M and that determining the first electrical parameter E of the medium M also enables the determination of the volume fraction V%_P2 of the second phase P2 of the medium M, for example.

[0033] Figure 7The measuring device 2 in the embodiment is a magnetic-inductive flowmeter, which comprises a measuring volume 6 for accommodating a medium M, which is a measuring tube through which the medium M flows. The medium M has a first phase P1 and at least temporarily a second phase P2, the first phase P1 having a first value E1 of a first electrical parameter E, the second phase P2 having a second value E2 of the first electrical parameter E. The measuring device 2 comprises a control and evaluation unit 4 and an electrode pair 3 in contact with the medium M, wherein the control and evaluation unit 4 generates a magnetic field B by means of a magnetic field generating device 5 in the operating state of the measuring device 2 in order to perform the main measurement task, i.e., to measure the volume flow through the measuring tube 6, by means of which magnetic field - provided that the medium M is electrically conductive - a measurement voltage U is generated in the medium M which is dependent on the flow velocity and is proportional to the flow velocity. The measurement voltage U is tapped by means of the electrode pair 3. Thus, flow information is obtained by means of the measuring device 2, which in the present embodiment is a magnetic-inductive flowmeter. A magnetic-inductive flowmeter is a typical example of a measuring device 2 which already has an electrode pair 3 , although this electrode pair 3 has a different task besides the original measurement task (flowmetering), namely the passive reception of the measurement voltage U induced in the medium M.

[0034] The measuring device 2 need not be Figure 7 As in the example shown in FIG. 1 , it assumes an additional measuring task, which can also be used in a simple manner to determine the volume fractions V% of the phases of a multiphase medium M.

[0035] In order to determine the volume fraction V% of the phases of the multiphase medium M, a plurality of electrical excitation signals are applied to the medium M by the electrode pair 3 and a plurality of corresponding electrical reaction signals are detected for the electrical excitation signals. Based on the plurality of excitation signals and the plurality of reaction signals, a plurality of values ​​En of a first electrical parameter E of the medium M are determined. In the prior art, for example, the electrical conductivity of the medium M is determined as the first electrical parameter E, and the volume fraction V% of the phases P1 and P2 of the medium M involved is inferred based on the determined electrical conductivity of the medium.

[0036] Direct determination of the volume fraction V% of a phase of the medium M has various disadvantages, which are partly dependent on a material change of at least one of the participating phases of the medium M in the considered measurement volume 6 and thus on a change characteristic of the first electrical parameter E of the participating phases P1 , P2 .

[0037] The method 1 described here provides a significantly different approach. The method 1 provides that discrete values ​​S(En) of a statistical dispersion measure S are determined from a plurality of determined values ​​En of a first electrical parameter E of a medium M, and that the volume fraction V%_P2 of the second phase P2 in the medium M is determined using the determined discrete values ​​S(En) of the first electrical parameter, using a mathematical relationship f between the statistical dispersion measure S of the first electrical parameter E and the volume fraction V%_P2 of the second phase in the medium M.

[0038] Method 1 is based on the knowledge that not only the instantaneous value of the first electrical parameter E of the medium M, as is known from the prior art, provides information about the volume fraction V%_P2 of the second phase P2 in the medium, but surprisingly also the discrete values ​​S(En) of the statistical dispersion measure S based on a plurality of measured values ​​of the first electrical parameter E. The determination of the volume fraction V%_P2 of the second phase P2 in the medium M is therefore independent to a certain extent of the absolute value of the first electrical parameter E of the medium M.

[0039] Method 1 is based on the discovered relationship in Figure 1 In the example of using Figure 7 . The present invention is shown in Figure 1, which is a real measurement performed by the magnetic-inductive flow measuring device 2 shown in Figure 2. Different measurements have been made on a first electrical parameter E of the medium M. On the one hand, the conductivity σ of the medium M was determined as the first electrical parameter E, and on the other hand, the medium impedance was determined, which is an alternating current variable and, as such, has a magnitude (abs (Impedanz)) and a phase. These measurements are shown in Figure 1. Figure 1 The upper row of the figure shows. Figure 1 In the lower row of , a plurality of measurement results En of the corresponding first electrical parameter E in the form of the conductivity σ and the standard deviation S of the absolute value and the phase of the impedance of the medium M are shown. The measurements were carried out at different frequencies.

[0040] Figure 1 The measurement in is carried out in such a way that, with a constant volume flow of the first electrically conductive phase P1 of the medium (water, liquid at a flow rate of 2.4 liters / second), the admixture of the second phase P2 of air (gaseous) is always increased. In this respect, a change in the volume flow of a phase also corresponds in a meaningful way to a change in the volume fraction of this phase. Not only is a measurement of the conductivity σ of the medium M shown, but also a measurement of the complex-valued impedance of the medium, which is divided into the absolute value of the impedance and the phase of the impedance. For each admixture of the second phase (air) P2 of the medium M, a plurality of values ​​En of the electrical parameter E of the medium M are recorded. Subsequently, a discrete value S(En) of a statistical dispersion measure S is determined from a plurality of determined values ​​En of the first electrical parameter E of the medium M. The standard deviation is selected as the statistical dispersion measure S. Surprisingly, however, it is still possible to identify that a relationship f which can often be linearly approximated exists in many cases between the volume fraction V%_P2 of the second phase in the medium M (which emerges directly from the admixture of air in the second phase P2) and the standard deviation S of the corresponding values ​​S(En) of the first electrical parameter E.

[0041] In the method 1 implemented here, the excitation signal is a voltage or a current, and the electrical reaction signal is therefore a current or a voltage. If the electrical parameter E of the medium M is an AC variable, such as impedance or admittance, then the excitation signal is usually a harmonic vibration with an excitation frequency corresponding thereto.

[0042] The application of the electrical excitation signal to the medium M takes place in a time range in which no other measured value acquisition is carried out in the medium M, in which case in particular Figure 7 In the case of the magnetic-inductive measuring device 2, these measurements are carried out after switching the polarity of the magnetic field B generated by the magnetic field device 5, i.e. in the time range of the non-stationary magnetic field B. If a measuring device is used for carrying out the method 1 which has absolutely no other measuring tasks, i.e. is only used for determining the volume fractions V% of the phases of the multiphase medium M, or has only measuring tasks which do not physically conflict with the determination of the volume fractions, then it is naturally not necessary to take into account possible conflicts with other measured value detections.

[0043] Figure 2 The important method steps for implementing method 1 are shown. In the top method step, it is shown that a multiphase medium M having phases P1 and P2 is located in a measurement volume 6. A plurality of electrical excitation signals are applied to the medium M by means of an electrode pair 3 and a plurality of corresponding electrical response signals are detected for these electrical excitation signals. Based on these signals, a plurality of values ​​En of a first electrical parameter of each medium, such as conductivity, impedance, admittance, etc., are determined. In the middle method step, discrete values ​​S(En), such as the standard deviation, of a statistical dispersion measure S are determined based on the plurality of values ​​En of the first electrical parameter E. In the last method step, finally, the specific volume fraction V%_P2(S(En)) of the second phase P2 is determined using the mathematical relationship f between the statistical dispersion measure S or the discrete values ​​S(En) determined therefrom and the volume fraction V%_P2 of the second phase in the medium M.

[0044] Figures 3 to 6 The measurement results obtained by means of method 1 regarding the volume fraction V%_P2 of the second phase P2 of the medium M are shown. In the respective upper diagrams of the accompanying drawings, the measured values ​​of the first electrical variable are shown at time t over a relatively large period of almost two hours. In the respective lower diagrams of the accompanying drawings, the corresponding curves of the actual (dashed line) and the determined volume fraction V%_P2 of the second phase P2 of the medium M are shown. The actual curve of the volume fraction V%_P2 of the medium M is constant over a wide time range. The measurement results are formed in the measuring device, which allows: the volume fraction V% of the phases P1, P2 of the medium M to be accurately given. The measuring device 2 is used according to Figure 7 A magnetic-inductive measuring device, whose control and evaluation unit 4 is designed in such a way that it can carry out the above-described method 1 during operation.

[0045] In accordance with Figure 3 In method 1, the conductivity σ of the medium M is applied as the first electrical parameter E of the medium M.

[0046] In accordance with Figure 4 In method 1, the impedance of the medium M, i.e. a two-valued electrical parameter, is used as the first electrical parameter E of the medium M, which is defined as the excitation and response signal in conjunction with the harmonic alternating variable. Figure 4 The above figure shows the magnitude of impedance and the phase of impedance.

[0047] exist Figure 5 and 6 Only one of the two parameters of the complex-valued impedance is treated in Figure 5 The magnitude of the impedance is handled in Figure 6 The phase of the impedance is handled in .

[0048] These diagrams also show that the method based on the use of the value S(En) of the statistical dispersion measure S, based on the ascertained value En of the first electrical parameter E, is very suitable also for quantitatively determining the volume fraction V%_P2 of the second phase P2 of the multiphase medium M.

[0049] In addition, according to Figure 3 and 5 In method 1 of , the ascertained discrete values ​​S(En) of the first electrical parameter E (absolute value of conductivity, impedance) are normalized to the absolute value of the first electrical parameter E, here correspondingly to the absolute average value of the first electrical parameter E calculated from a plurality of ascertained values ​​En of the first electrical parameter E of the medium M. This results in a great insensitivity to material changes of the phases P1, P2 of the medium M, since these are no longer relevant due to the normalization to the absolute value of the first electrical parameter. Such a normalization of the phase angle is naturally not necessary, since this phase angle is independent of the material properties of the medium and can always only lie in a limited absolute range.

[0050] In a preferred implementation of method 1, which is not explicitly shown here, a plurality of values ​​of a second electrical parameter of the medium M are determined based on a plurality of excitation signals and a plurality of response signals. If, for example, the magnitude of the impedance is used as the first electrical parameter, the phase angle of the impedance can be used as the second electrical parameter. Subsequently, discrete values ​​of a statistical dispersion measure are also determined based on a plurality of determined values ​​of the second electrical parameter for the medium M. The volume fraction of the second phase in the medium is determined using the determined discrete values ​​of the second electrical parameter using the mathematical relationship between the statistical dispersion measure of the second electrical parameter and the volume fraction of the second phase in the medium M. In this embodiment, it is very suitable to calculate the average volume fraction of the second phase of the medium based on the volume fraction V%_P2 of the second phase P2 of the medium M determined using the first electrical parameter E of the medium M and based on the volume fraction of the second phase of the medium determined using the second electrical parameter of the medium.

[0051] Method 1 implemented in the measuring device 2 stipulates that the volume fraction V%_P2 of the second phase P2 in the medium M, which is obtained using the first electrical parameter E of the medium M and / or the volume fraction of the second phase of the medium M, which is obtained using the second electrical parameter of the medium and / or the average volume fraction of the second phase P2 in the medium M are represented by a signal, that is, optionally stored in the memory of the control and analysis processing unit 4 and / or displayed and / or transmitted to a connected communication partner via the communication interface of the measuring device 2.

[0052] In addition, the implementation of method 1 in the measuring device 2 stipulates that when the volume fraction V%_P2 of the second phase P2 in the medium M, calculated using the first electrical parameter E of the medium M, exceeds a first boundary value and / or the volume fraction of the second phase of the medium M, calculated using the second electrical parameter of the medium, exceeds a second boundary value and / or the average volume fraction of the second phase in the medium exceeds a third boundary value, the presence of two-phase flow is indicated by a signal, that is, it can be optionally stored in the memory of the control and analysis unit 4 and / or displayed and / or transmitted to a connected communication partner via the communication interface of the measuring device 2.

[0053] Consider Figure 1 From the illustration of the functional relationship f in (the three views below), it can be understood that the mathematical relationship f between the statistical discrete measure S of the first electrical parameter E and the volume fraction V%_P2 of the second phase of the medium M is determined in this way, wherein discrete values ​​S(En) of the first electrical parameter E are determined in the case of at least two different but known volume fractions V%_P2 of the second phase P2 of the medium M, wherein Figure 1 The volume fraction V% in the medium M corresponds to the flow component of the second phase P2 In these exemplary embodiments, a linear relationship between the statistical dispersion measure S of the first electrical parameter E and the volume fraction V%_P2 of the second phase P2 of the medium M is employed.

[0054] Reference numerals

[0055] 1 Method

[0056] 2. Measuring equipment

[0057] 3 electrode pairs

[0058] 4Control and analysis processing unit

[0059] 5 Magnetic field device

[0060] 6. Measurement volume, measuring tube

[0061] B Magnetic Field

[0062] UInduction voltage

[0063] V% Volume share

[0064] MMultiphase medium

[0065] The first and second phases of P1 and P2 media

[0066] The first electrical parameters of E medium

[0067] E1 The first value of the first electrical parameter of the first phase

[0068] E2 The second value of the first electrical parameter of the second phase

[0069] En Multiple determined values ​​of the first electrical parameter

[0070] S statistical dispersion measure

[0071] S(En) Discrete values ​​of multiple values ​​En of the first electrical parameter

[0072] f The statistical dispersion measure S of the first electrical parameter E and the volume of the second phase in the medium M

[0073] Relationship between share V%_P2

[0074] V%_P2 Volume fraction of the second phase P2 in the medium M

[0075] Sigma conductivity

Claims

1. A method (1) for determining the volume fractions (V%) of phases of a multiphase medium (M), wherein the medium (M) has a first phase (P1) and at least temporarily a second phase (P2), the first phase (P1) having a first value (E1) of a first electrical parameter (E), the second phase (P2) having a second value (E2) of the first electrical parameter, wherein a plurality of electrical excitation signals are applied to the medium (M) via an electrode pair (3) and a plurality of corresponding electrical reaction signals are detected for the electrical excitation signals, wherein a plurality of values ​​(En) of the first electrical parameter (E) of the medium (M) are determined based on the plurality of excitation signals and the plurality of reaction signals, It is characterized in that determining a discrete value (S(En)) of a statistical dispersion measure (S) from a plurality of determined values ​​(En) of the first electrical parameter (E) of the medium (M), The volume fraction (V%_P2) of the second phase (P2) in the medium (M) is determined using the determined discrete values ​​(S(En)) of the first electrical parameter (E) by using a mathematical relationship (f) between the statistical discrete measure (S) of the first electrical parameter (E) and the volume fraction (V%_P2) of the second phase (P2) in the medium (M).

2. The method (1) according to claim 1, characterized in that: The excitation signal is a voltage or a current, and the electrical response signal is a current or a voltage, in particular wherein the excitation signal is a harmonic vibration having an excitation frequency.

3. The method (1) according to claim 1 or 2, characterized in that: The electrical excitation signal is applied to the medium (M) within the following time range, wherein no other measured value detection is performed in the medium (M), in particular no magnetic inductive flow measurement is performed in the case of a magnetic inductive measuring device, in particular after switching the polarity of the magnetic field (B), in particular within the time range of a non-stationary magnetic field (B).

4. The method (1) according to any one of claims 1 to 3, characterized in that The standard deviation is calculated as a statistical dispersion measure (S).

5. The method (1) according to any one of claims 1 to 4, characterized in that The first electrical parameter (E) of the medium (M) is the electrical conductivity (σ) of the medium (M) and / or the magnitude of the impedance of the medium (M) and / or the phase angle of the impedance of the medium (M), in particular the electrical conductivity is determined based on the real part of the impedance of the medium (M) taking into account the diameter of the measurement volume (6) of the medium (M).

6. The method (1) according to any one of claims 1 to 5, characterized in that The ascertained discrete values ​​(S(En)) of the first electrical parameter are normalized to the absolute value of the first electrical parameter (E), in particular to an absolute average value of the first electrical parameter (E) calculated from the plurality of ascertained values ​​of the first electrical parameter (E) of the medium (M).

7. The method (1) according to any one of claims 1 to 6, characterized in that A plurality of values ​​of a second electrical parameter of the medium (M) are obtained based on the plurality of excitation signals and the plurality of response signals; discrete values ​​of a statistical discrete measure are obtained based on the plurality of obtained values ​​of the second electrical parameter of the medium (M); and the volume fraction of the second phase in the medium is determined using the obtained discrete values ​​of the second electrical parameter by using a mathematical relationship between the statistical discrete measure of the second electrical parameter and the volume fraction of the second phase in the medium (M).

8. The method (1) according to claim 7, characterized in that The average volume fraction of the second phase of the medium (M) is calculated based on the volume fraction (V%_P2) of the second phase (P2) of the medium (M) determined using the first electrical parameter (E) of the medium (M) and based on the volume fraction of the second phase of the medium determined using the second electrical parameter of the medium.

9. The method (1) according to any one of claims 1 to 8, characterized in that The volume fraction (V%_P2) of the second phase (P2) in the medium (M) calculated using the first electrical parameter (E) of the medium (M) and / or the volume fraction of the second phase in the medium (M) calculated using the second electrical parameter of the medium and / or the average volume fraction of the second phase (P2) in the medium (M) are represented by a signal, in particular stored in a memory of a control and analysis unit (4) and / or displayed and / or transmitted to a connected communication partner via a communication interface of the measuring device (2).

10. The method (1) according to any one of claims 1 to 9, characterized in that When the volume fraction (V%_P2) of the second phase (P2) in the medium (M) calculated using the first electrical parameter (E) of the medium (M) exceeds a first boundary value and / or the volume fraction of the second phase in the medium (M) calculated using the second electrical parameter of the medium exceeds a second boundary value and / or the average volume fraction of the second phase in the medium exceeds a third boundary value, the presence of a two-phase flow is indicated by a signal, in particular the presence of the two-phase flow is stored in a memory of a control and analysis unit (4) and / or displayed and / or transmitted to a connected communication partner via a communication interface of the measuring device (2).

11. The method (1) according to any one of claims 1 to 10, characterized in that A mathematical relationship (f) between a statistical discrete measure (S) of the first electrical parameter (E) and the volume fraction (V%_P2) of the second phase of the medium and / or a mathematical relationship between a statistical discrete measure of the second electrical parameter and the volume fraction (P2) of the second phase of the medium (M) is determined by determining discrete values ​​(S(En)) of the first electrical parameter (E) and / or discrete values ​​of the second electrical parameter in the case of at least two different but known volume fractions (V%_P2) of the second phase (P2) of the medium (M), in particular wherein a linear relationship is adopted between the statistical discrete measure of the first electrical parameter and the volume fraction of the second phase of the medium and / or between the statistical discrete measure of the second electrical parameter and the volume fraction of the second phase of the medium.

12. The method (1) according to claim 11, characterized in that More than two supporting points are used, that is, more than two relationships are used between the statistical discrete measure (S) of the first electrical parameter (E) and the volume fraction (V%_P2) of the second phase (P2) of the medium (M); and a polynomial description of the mathematical relationship (f) between the statistical discrete measure (S) of the electrical parameter (E) and the volume fraction (V%_P2) of the second phase (P2) of the medium (M) is obtained or a description of the relationship is obtained by spline interpolation, in particular when the description of the relationship is optimized by minimizing a deviation measure.

13. Measuring equipment (2), including: A measuring volume (6) for accommodating a medium (M), wherein the medium (M) has a first phase (P1) and at least temporarily a second phase (P2), the first phase (P1) having a first value (E1) of a first electrical parameter (E), and the second phase (P2) having a second value (E2) of the first electrical parameter (E); a control and analysis unit (4); an electrode pair (3) in contact with the medium (M), wherein the control and analysis unit (4) applies a plurality of electrical excitation signals to the medium (M) via the electrode pair (3) in an operating state of the measuring device (2) and detects a plurality of corresponding electrical reaction signals for the electrical excitation signals, wherein a plurality of values ​​(En) of the first electrical parameter (E) of the medium (M) are determined based on the plurality of excitation signals and the plurality of reaction signals, It is characterized in that The control and evaluation unit (4) is designed in such a way that the measuring device (2) carries out the method (1) according to one of claims 1 to 12 during operation.

14. The measuring device (2) according to claim 13, characterized in that The measuring device (2) is a magnetic inductive flow measuring device, comprising an electrode pair (3) for receiving a voltage induced in the medium (M), wherein the electrode pair (3) is also used to apply a plurality of electrical excitation signals to the medium.

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