Magnetic induction type flowmeter

Abstract

To provide a magnetic-inductive flowmeter which has reduced sensitivity to changes in a flow profile of a medium to be measured with respect to the flow profile.SOLUTION: In a magnetic-inductive flowmeter (1), a magnetic field guiding device (5) extends to close in a circumferential direction around a measuring tube (2), coils (4) are arranged distributed over a circumference of the magnetic field guiding device (5), and the magnetic field guiding device (5) acts as a coil core in a region of the coils (4), such that the coils (4) are likewise arranged with their coil longitudinal axes in the circumferential direction of the measuring tube (2), and that at least three coils (4a, 4b, and 4c) and at least three measuring electrodes (6a, 6b, and 6c) are arranged, and where each of the measuring electrodes (6a, 6b, and 6c) is arranged between two coils (4a, 4b, and 4c) as viewed in a radial direction from a center of the measuring tube (2), whereby, a plurality of measuring voltages having an effectiveness distribution distributed over a cross section of the measuring tube (2) are formed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a magnetic induction type flow measuring device comprising a measuring tube for guiding a conductive medium, a magnetic field device having a plurality of coils for forming a magnetic field that at least partially penetrates the measuring tube perpendicular to the flow direction of the medium, and a magnetic field guide device for guiding the magnetic field in each region outside the measuring tube, measuring electrodes for extracting at least one measuring voltage induced in the medium, and a control evaluation device for forming a magnetic field by passing a current through at least one of the coils and evaluating the measuring voltage. [Background technology]

[0002] Many magnetoinductive flowmeters are known from the prior art. As essential functional components, a magnetoinductive flowmeter comprises at least one measuring tube for guiding an electrically conductive medium and measuring its flow rate, and a magnetic field device with a number of coils for generating a magnetic field that at least partially penetrates the measuring tube perpendicular to the flow direction of the medium. The magnetoinductive flowmeters known from the prior art also comprise a magnetic field guide device for guiding the magnetic field regionally outside the measuring tube and measuring electrodes for tapping off a measuring voltage induced in the medium.

[0003] The measurement principle on which magnetoinductive flow measurement is based is based on the separation of moving charges in an external magnetic field. As a result of the charge separation, a measurement voltage is induced in the medium, which can be tapped off and evaluated using measuring electrodes. From the evaluation of the measurement voltage, information is obtained about the flow velocity of the medium (averaged over the cross section of the measuring tube) and thus about the volumetric flow rate through the measuring tube.

[0004] Although the magnetic induction flow measurement method in the prior art has indeed proven to be a reliable measurement method, it is known that the magnetic induction flow measurement device reacts sensitively to the flow profile or changes in the flow profile of the medium flowing through the measuring pipe, or that the measurement accuracy with which the magnetic induction flow measurement device can perform measurements depends on disturbances and asymmetries in the flow profile.

[0005] To describe the electromagnetic relations between the point-tap measuring voltage, the magnetic field distribution in the relevant volume of the measuring tube, the velocity distribution of the medium (flow profile) and the electric field distribution resulting from induction, a systematic study was presented by Shercliff et al., from which the concept of the so-called weight-function emerged. According to this, for the physical description of the processes in the magneto-inductive flowmeter, the electrode voltage is calculated by the volume integral over the internal space of the magneto-inductive flowmeter, the integrand is the scalar product of the aforementioned weight function and the velocity field of the flow. The position-dependent weight function thus describes to what extent the flow elements in the volume of the magneto-inductive flowmeter contribute differently to the measuring voltage. The greater the spatial variability of the weight function, the more sensitive the flow measurement is to changes in the flow profile. The description of these relations quickly becomes complicated and can only be deduced for ideal assumptions regarding the geometry of the measuring tube, the arrangement of the measuring electrodes and the magnetic field distribution. In either case, the weighting function approach makes it clear that the velocity components distributed over the flow cross section or flow volume contribute with different magnitudes to the induced measurement voltage, so that for equal mean volumetric flow rates, different velocity profiles can result in different measurement voltages.

[0006] Magnetoinductive flow measuring devices are often installed in process installations where the medium is guided in a piping system. In this case, various types of piping systems, such as, for example, T-shaped pieces or bent pipes or varying cross sections per pipe segment, can affect the flow profile in the magnetoinductive flow measuring device and thus the accuracy of the flow measurement. Therefore, in the prior art, it is noted that the flow profile in the flow measuring device is as free and symmetrical as possible, which requires inlet and outlet sections of defined length, the use of flow straighteners, etc. Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE DISCLOSURE The object of the invention is therefore to provide a magnetoinductive flow measuring device which has reduced sensitivity to the flow profile, in particular to changes in the flow profile of the medium to be measured. [Means for solving the problem]

[0008] This object is achieved by a magnetic induction flow measuring device according to claim 1, in which the magnetic field guide device extends in a circumferential direction so as to close the circumference of the measuring tube, the coils are distributed over the circumference of the magnetic field guide device, the magnetic field guide device acts as a coil core in the area of ​​the coils, whereby the coils are arranged such that they likewise have their coil longitudinal axis in the circumferential direction of the measuring tube, and at least three coils and at least three measuring electrodes are provided, each of the measuring electrodes being arranged between two coils in the radial direction as viewed from the center of the measuring tube.

[0009] The structural design of the magnetoinductive flow measuring device results in various advantages. Since the coils are arranged with their coil longitudinal axis in the circumferential direction of the measuring tube, the position of the coils does not structurally determine the inflow area of ​​the magnetic field into the measuring tube. In contrast to the usual design, the coil longitudinal axis of the coils is mostly oriented radially relative to the measuring tube (and not in the circumferential direction of the measuring tube), so that in this case the position of the coils structurally determines the point at which the magnetic field generated by the coils flows into the measuring tube. In this sense, the coil longitudinal axis is understood to be the direction in which the coils generate a magnetic field when current is applied. By arranging the coils over the periphery of the magnetic field guide device, it is possible to determine at which point the magnetic field generated by the coils flows into and out of the measuring tube simply by applying current to the coils in a targeted manner, so that the control and evaluation device can essentially change the magnetic field in its direction by applying current to the coils in a targeted manner. This therefore means not only a simple polarity reversal of the magnetic field, i.e. a rotation of the magnetic field by 180°, but also a change in the direction of the magnetic field beyond simple anti-parallelism.The above-mentioned arrangement of the coils around the magnetic field guide device, which extends in the circumferential direction of the measuring tube, also allows a particularly space-saving construction, since no additional space can be provided in the direction towards the measuring tube, i.e. in the radial direction to the measuring tube, as is typical in the prior art.

[0010] Assuming that the coil's longitudinal axis is arranged in the circumferential direction relative to the measuring tube, this coil may be a straight coil, i.e. its straight center line extends in a substantially tangential direction relative to the magnetic field guiding device, but it may also be an arc-shaped coil that follows the possible arc-shaped extension of the magnetic field guiding device, i.e. its center line is also arc-shaped and follows the magnetic field guiding device in a curved extension.

[0011] At least three coils ensure that the magnetic field direction changes described above are possible (not just simple direction reversals).

[0012] The use of at least three measuring electrodes arranged between the two coils structurally ensures that not only a 180° direction reversal can be achieved, but also multiple measuring paths with different extension directions in relation to the center of gravity in the cross section of the measuring tube.

[0013] For this reason, the above-described magnetic induction flow measuring device is structurally capable of applying magnetic fields oriented in different directions to the medium in the measuring tube and of extracting different measuring voltages from the measuring paths oriented in different directions, so that a significantly better average can be obtained over asymmetric flow profiles, thereby significantly reducing the sensitivity of the magnetic induction flow measuring device to variable flow profiles.

[0014] Each of the measuring electrodes is respectively arranged between two coils in the radial direction as viewed from the center of the measuring tube, so that the electrical contact of the measuring electrodes with the coils distributed on the circumferential surface of the magnetic field guide device is not spatially hindered. Although it is assumed that each of the measuring electrodes is arranged between two coils in the radial direction as viewed from the center of the measuring tube, this does not of course mean that a measuring electrode must be arranged between two coils, but only means that the measuring electrode provided is in each case arranged between two coils, i.e. is not aligned with one of the coils distributed on the circumferential surface of the magnetic field guide device as viewed from the center of the measuring tube.

[0015] An advantageous configuration of the magnetoinductive flow measuring device is characterized in that the magnetic field guide device forms a ring curved in the shape of a circular arc. Particularly preferably, the ring is shaped circularly or elliptically at least in areas. In another variant, the magnetic field guide device forms a polygonal ring. The polygonal ring further preferably forms a hexagonal or octagonal polygon. In particular, the polygon preferably has alternating long and short legs. In a particularly preferred variant, the coil is arranged on the long legs.

[0016] Another advantageous configuration of the magnetoinductive flowmeter is characterized in that the control and evaluation device energizes at least a part of the coil in at least one first operating mode such that the magnetic field formed in the area of ​​the measuring tube is oriented in a first operating direction, and in at least one second operating mode such that the magnetic field formed in the area of ​​the measuring tube is oriented in a second operating direction different from the first operating direction. In this case too, "different directions" does not mean the narrow case of antiparallel, but rather that the magnetic fields formed are mutually inclined at angles different from 0° and 180°. It is also possible, and this is not excluded, to realize only a reversal of the magnetic field, but in any case a change of direction in the sense described here must also be realized in addition to this.

[0017] In the configuration according to the invention, it is possible to generate a magnetic field in at least two different operating directions based on the current passing through at least a part of the coil. For each operating direction, the magnetic field can have two orientations, i.e. a first orientation and a second orientation opposite to this, i.e. rotated by 180° with respect to the first orientation. The different operating directions can be generated in different ways, for example by current passing through different parts of the coil, in which case the parts do not have a common coil, although in other embodiments the parts may have a common coil with another given part. It is also possible to current the same coil, for example in different directions and / or with different intensities.

[0018] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that the control and evaluation device energizes a number of coils in at least the first and second operating directions, respectively, in order to generate a magnetic field.

[0019] In a preferred embodiment of the magnetoinductive flowmeter, the control and evaluation device controls the change in the current to the coil as abruptly as possible, so that, for example, the transition between different operating modes can be quickly realized in any order. In order to achieve such abrupt or rectangular current characteristic, it is necessary to operate at a relatively large voltage in each time, since the effective current-voltage area is known and deterministic for the change in current in the coil. In an alternative embodiment, the control and evaluation device controls the change in the current to the coil so that it is sinusoidal, and preferably a continuous sinusoidal current characteristic is realized. A special feature of this description is that, in particular, no voltage peaks occur in a continuous sinusoidal current characteristic, so that the current state of the coils involved is of course set in time, so that the possible operating modes are also limited in this embodiment.

[0020] Advantageously, the control and evaluation device energizes the coils in such a way that the realized magnetic circuit as a whole, in particular the magnetic field device and the magnetic field guide device, operates in a linear region, in particular avoiding regions of magnetic saturation. Under these preconditions, the measurement system as a whole can be considered to operate linearly, so that, for example, linear superposition of physical effects can be easily based on.

[0021] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that the measuring electrodes are arranged between the two coils in the radial direction as viewed from the center of the measuring tube, such that at least one first pair of measuring electrodes forms a first measuring section with a first measuring section direction, where the first measuring section direction and the first operating direction of the magnetic field are inclined to each other, preferably by more than 45° to each other, very preferably by 90° to each other. Furthermore, the above-mentioned advantageous configuration is characterized in that at least one second pair of measuring electrodes forms a second measuring section with a second measuring section direction, where the second measuring section direction and the second operating direction of the magnetic field are likewise inclined to each other, preferably by more than 45° to each other, very preferably by 90° to each other. The more the measuring section direction is inclined to the operating direction of the magnetic field, the more effective the separation of the charges in the measuring section direction and thus the better the induced electrical measuring voltage can be detected by the measuring technique.

[0022] All embodiments have in common that the different detected measuring voltages are utilized by a control and evaluation device, from which the volume flow through the measuring tube is calculated. Due to the variety of operating directions of the magnetic field and the variety of differently oriented measuring voltages, flow rate information can be obtained that is clearly independent of the flow profile.

[0023] Another advantageous configuration of the magnetoinductive flow measurement device is characterized in that the control and evaluation device performs a first operating mode at least once in order to calculate the improved flow measurement value in the measurement sequence, in which a first measurement voltage and / or a first flow measurement value are calculated by a first pair of measuring electrodes in the first operating mode, performs a second operating mode at least once in which a second measurement voltage and / or a second flow measurement value are calculated by a second pair of measuring electrodes in the second operating mode, and calculates the improved flow measurement value from the first and second measurement voltages and / or from the first and second flow measurement values. Particularly preferably, the improved flow measurement value is formed by the control and evaluation device by forming an average value from the first and second measurement voltages and / or by forming an average value from the first and second flow measurement values.

[0024] Another advantageous configuration of the magnetoinductive flow measurement device is characterized in that the control and evaluation device executes a first operating mode at least twice in a measurement sequence, whereby a magnetic field is generated in one orientation and in another (i.e. opposite) orientation of a first operating direction of the magnetic field, and in each orientation of the first operating direction of the magnetic field, a corresponding sub-measurement voltage / sub-flow measurement value is recorded by a first pair of measuring electrodes and a first flow measurement value is calculated from the sub-measurement voltage / sub-flow measurement value, and the control and evaluation device executes a second operating mode at least twice in a measurement sequence, whereby a magnetic field is generated in one orientation and in another (i.e. opposite) orientation of a second operating direction of the magnetic field, and in each orientation of the second operating direction of the magnetic field, a corresponding sub-measurement voltage / sub-flow measurement value is recorded by a second pair of measuring electrodes and a second flow measurement value is calculated from the sub-measurement voltage / sub-flow measurement value, in order to eliminate the electrochemical potential at the measuring electrodes that does not change with the orientation of the magnetic field.

[0025] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that the control and evaluation device executes the measurement sequence at least once per unit time in such a way that the magnetic field is first generated sequentially in two orientations of the first or second operating direction and then generated sequentially in the second or first operating direction, in particular in that the orientations of the operating directions are alternately driven sequentially several times.

[0026] Another advantageous configuration of the magnetoinductive flowmeter is characterized in that the control and evaluation device executes the measurement sequence at least once per time in such a way that the orientation of at least two operating directions of the magnetic field is successively controlled to generate a stepped rotating magnetic field as seen in the axial direction of the measuring tube. Depending on the concrete configuration of the coil arrangement, the advantage of this operating method may be that when changing the operating direction, the excitation of the previously energized coil can be simply damped, while the other coils have to be switched from a de-energized state to an energized state, but the period for achieving a steady energized state is achieved more quickly than if the previously energized coils had to be energized in the opposite direction.

[0027] A preferred configuration of the magnetoinductive flow measuring device is characterized in that in at least one intermediate operating mode, the control and evaluation device energizes at least some of the coils in such a way that the generated magnetic field is oriented in an intermediate operating direction in the area of ​​the measuring tube, the intermediate operating direction being oriented differently from the first and second operating directions and possibly from further operating directions, in particular when generating a magnetic field in the intermediate operating direction, fewer coils are energized than when energizing for generating a magnetic field in the operating directions. The measure for generating an intermediate operating direction takes into account the idea of ​​magnetically exciting the medium in the measuring tube in several operating directions in order to be able to derive volume flow information that is as averaged as possible and independent of the flow profile.

[0028] Another advantageous embodiment of the magnetoinductive flowmeter is characterized in that the control and evaluation device, in at least one intermediate operating mode, causes currents of different magnitudes to be applied to at least some of the coils in such a way that the generated magnetic field is oriented in an intermediate operating direction in the area of ​​the measuring tube, the intermediate operating direction being oriented differently from the first and second operating directions and possibly from the further operating directions. This measure makes use of the constructional feature of the magnetoinductive flowmeter, that without establishing a structural entry point of the magnetic field into the interior space of the measuring tube (e.g. due to the otherwise general constructional design of the pole shoe), the coils are arranged with their longitudinal axis (=direction of the magnetic field generated by the coils) in the circumferential direction of the measuring tube, and the point of entry of the magnetic field from the magnetic field guide device into the interior space of the measuring tube is determined by the current-passing state of the coils. Only by selecting currents of different magnitudes for the current passing through the coils in this way is it possible to adjust and measure the direction of the magnetic field in the measuring tube.

[0029] In a preferred variant, fewer coils are energized when generating a magnetic field in the intermediate operating direction than when energizing for generating a magnetic field in the operating direction.

[0030] Another advantageous configuration of the magnetoinductive flow measurement device is characterized in that the control and evaluation device, in addition to determining the measurement voltages / flow measurement values ​​from at least a first operating mode and at least a second operating mode, determines at least one intermediate measurement voltage / intermediate flow measurement value in an intermediate operating mode by means of a pair of measurement electrodes and determines the improved flow measurement value from the first measurement voltage / first flow measurement value, the second measurement voltage / second flow measurement value and the intermediate measurement voltage / intermediate flow measurement value. Similar to the use of the flow measurement values, the use of the (intermediate) measurement voltage recorded by the pair of measurement electrodes can also be identified.

[0031] In particular, an improved flow measurement value is formed from the first measurement voltage / first flow measurement value, the second measurement voltage / second flow measurement value and the intermediate measurement voltage / intermediate flow measurement value by averaging.

[0032] Another advantageous configuration of the magnetoinductive flowmeter is characterized in that exactly three measuring electrodes are provided. The three measuring electrodes are arranged at an angle of 90° to 150° to one another, seen from the center of the measuring tube. In this case, the electrodes are preferably, but not necessarily, arranged symmetrically at an angle of 120° to one another. Furthermore, exactly three coils are arranged at an angle of 90° to 150° to one another. In this case, preferably, but not necessarily, the three coils are arranged symmetrically at an angle of 120° to one another and at an angle of 40° to 80°, in particular 60°, to the measuring electrodes. To generate a magnetic field in the three operating directions, the control and evaluation device energizes two of the coils for each operating direction.

[0033] Another advantageous configuration of the magnetoinductive flowmeter is characterized in that exactly three measuring electrodes are provided, which are arranged at an angle of 90° to 150° relative to one another, viewed from the center of the measuring tube. Particularly preferably, exactly three measuring electrodes are arranged symmetrically at an angle of 120° relative to one another. Furthermore, six coils are provided. As viewed from the center of the measuring tube, every two coils of the six coils have one measuring electrode between them, and every two measuring electrodes have two coils between them. Preferably, every three coils of the six coils are respectively arranged at an angle of 120° relative to one another, and both coils arranged adjacent to one measuring electrode are respectively arranged at the same angle to the measuring electrode.

[0034] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that, in order to generate a magnetic field in one operating direction, the control and evaluation device energizes at least four coils, preferably coils that are located symmetrically relative to the axis of the operating direction.

[0035] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that three measurement sections are realized by three measurement electrodes, and the control and evaluation device generates three magnetic fields in the three operating modes, each with a different operating direction, performs all three operating modes in a measurement sequence, obtains three measurement voltages / three flow measurement values ​​from the three measurement sections, and obtains an improved flow measurement value from the three measurement voltages / three flow measurement values.

[0036] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that exactly four measuring electrodes are provided, arranged symmetrically at an angle between 70° and 110° to one another, in particular at an angle of 90° to one another, seen from the center of the measuring tube, and exactly four coils are arranged symmetrically at an angle between 70° and 110° to one another, in particular at an angle of 90° to one another and arranged at an angle between 35° and 55°, in particular at an angle of 45°, to the measuring electrodes, and in particular in order to generate a magnetic field in both operating directions, current is passed through all four coils for each operating direction by the control and evaluation device.

[0037] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that exactly four measuring electrodes are arranged at an angle of 70° to 110° to one another, in particular arranged symmetrically at an angle of 90° to one another, as viewed from the center of the measuring tube, and eight coils are arranged, in particular arranged such that, as viewed from the center of the measuring tube, every two of the eight coils have one measuring electrode between them and every two measuring electrodes have two coils between them, preferably four of the eight coils are arranged at an angle of 90° to one another, and both coils arranged adjacent to one measuring electrode are arranged at the same angle to the measuring electrode.

[0038] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that, in order to generate a magnetic field in one operating direction, the control and evaluation device energizes at least four coils, preferably coils that are located symmetrically relative to the axis of the operating direction.

[0039] Another advantageous configuration of the magnetoinductive flow measuring device is characterized in that, in order to generate a magnetic field in one operating direction, the control and evaluation device energizes exactly four coils, in particular the four coils that are located symmetrically with respect to the axis of the operating direction and are furthest from the axis of the operating direction.

[0040] As already mentioned above, the control and evaluation device calculates the volume flow rate of the medium, for example by forming an average value of the measured voltages / volume flows detected from different measurements in different operating modes. More generally, according to a preferred development, the control and evaluation device calculates the volume flow rate of the medium from a linear combination of a number of measured voltages / volume flows from the detected measured voltages / calculated volume flows, in particular the measured voltages / volume flows being weighted by weighting factors. For this purpose, calibration measurements with varying but known volume flows can be carried out. To determine the optimal selection of the linear relationship and / or the weighting factors, the weighting factors and the relationship can be determined by optimization methods.

[0041] According to another preferred development of the magnetoinductive flow measuring device, the control and evaluation device calculates the volume flow rate of the medium at a number of measured voltages / volume flow rates among the detected measured voltages / calculated volume flow rates from the various operating modes using a non-linear function.

[0042] In a preferred development of the magnetoinductive flow measuring device, the nonlinear function is formed by an artificial neural network with an input layer with at least a number of input neurons corresponding to the number of detected measurement voltages / calculated volume flows as input parameters, an output layer with at least one output neuron outputting at least the volume flow rate of the medium as output parameter, and at least one intermediate layer with at least two neurons, in particular the artificial neural network being trained with calibration data, which may originate from real calibration measurements, but also from corresponding numerical simulations, if they exist.

[0043] In particular, there are numerous means for constructing and developing the magnetoinductive flow measuring device according to the invention, for which reference is made to the claims subordinate to claim 1 as well as to the description of preferred embodiments in conjunction with the drawings. [Brief description of the drawings]

[0044] [Figure 1] 1 shows a schematic representation of a magnetoinductive flowmeter with a magnetic field device having a measuring tube and a coil, a magnetic field guide device, measuring electrodes and a control and evaluation device; [Diagram 2] 1 shows a schematic representation of a magnetoinductive flow measurement device in a cross section in the region of the magnetic field arrangement and the identifiable positions of the coils and measuring electrodes; [Diagram 3] 3A to 3C are diagrams illustrating an example of an operating mode for energizing a coil of a magnetoinductive flow measurement device and a measurement sequence. [Figure 4] 5A and 5B show schematic diagrams of another embodiment of an operating mode for energizing the coil of a magnetoinductive flow measurement device and another measurement sequence. [Diagram 5] 5A and 5B show schematic diagrams of another embodiment of an operating mode for energizing the coil of a magnetoinductive flow measurement device and another measurement sequence. [Figure 6] FIG. 2 is a schematic diagram of an embodiment using an intermediate operating mode for energizing the coil of a magnetoinductive flow measurement device. [Figure 7] 1A and 1B show schematic diagrams of examples of operating a magnetoinductive flow measurement device with a magnetic field device having three coils and six coils. [Figure 8] 1A and 1B show schematic diagrams of examples of operating a magnetoinductive flow measurement device with a magnetic field device having four coils and eight coils. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The figures show generally various aspects of the magnetic inductive flow measurement device 1 discussed in this specification, some of which are structural aspects and some of which are operational aspects of the magnetic inductive flow measurement device 1.

[0046] 1 shows a magnetoinductive flow measuring device 1 with a measuring tube 2 for guiding a conductive medium, a magnetic field device 3 with a number of coils 4 for generating a magnetic field B that at least partially penetrates the measuring tube 2 perpendicular to the flow direction of the medium and a magnetic field guide device 5 for guiding the magnetic field B in a region-by-region manner outside the measuring tube 2, measuring electrodes 6 for tapping off at least one measuring voltage U induced in the medium, and a control and evaluation device 7 for generating the magnetic field B by energizing at least one of the coils 4 and evaluating the measuring voltage U. The magnetoinductive flow measuring device 1 has a flange 8 at the end of the measuring tube 2, by means of which the measuring tube 2 can be integrated into a piping system of a fluid-technical process for which a flow determination is to be performed.

[0047] In the prior art, magneto-inductive flow measuring devices (not shown here) are used that differ from the configuration shown in FIG. 1 (and also in other figures). The magnetic field devices used in the prior art often consist of two coils arranged opposite each other on the circumference of the measuring tube with their axes pointing radially towards the centre of the measuring tube. These coils are again electrified. A magnetic pole shoe is often realised which constructively sets the point where the magnetic field formed by the radially oriented coils flows into the inner space of the measuring tube and flows out again. In most cases, two measuring electrodes are realised which record a measuring voltage induced in the flowing medium, which is essentially proportional to the flow velocity of the medium in the measuring tube averaged over the cross section of the measuring tube.

[0048] In contrast to this, the magnetic induction flow measurement device 1 shown in this specification is characterized in that the magnetic field guide device 5 extends in a circumferentially closed manner around the measuring tube 2, the coils 4 are distributed over the circumferential surface of the magnetic field guide device 5, and the magnetic field guide device 5 acts as a coil core in the area of ​​the coils 4, so that the coils 4 are arranged such that their longitudinal axis likewise runs in the circumferential direction of the measuring tube 2. Here, at least three coils 4 and at least three measuring electrodes 6 are provided, where each measuring electrode 6 is arranged between two coils 4 in the radial direction as viewed from the center of the measuring tube 2.

[0049] The illustrated magnetic induction type flowmeter 1 has the characteristic that the coil 4 is arranged with its longitudinal axis in the circumferential direction of the measuring tube 2, and therefore the position of the coil 4 does not structurally strictly define the inflow area of ​​the magnetic field B into the measuring tube 2. Since the coil 4 is arranged over the entire circumference of the magnetic field guide device 5, the position where the magnetic field B formed by the coil 4 flows into the measuring tube 2 and the position where the magnetic field B flows out of the measuring tube 2 can be determined by applying a current to the coil 4 in a desired manner, so that the magnetic field B can be basically made variable in its direction by applying a current to the coil 4 in a desired manner by the control evaluation device 7. This is based on the understanding that the inflow and outflow points of the magnetic field B are not point-like points on the circumferential surface of the magnetic field guide device 5, but are areas having a certain degree of expansion. According to this understanding, the said areas can be changed and adjusted by applying a current to the coil 4. This makes it clear that in either case, the position of the coil 4 itself is not the decisive inflow point of the magnetic field B into the measuring tube 2, and is not the decisive outflow point of the magnetic field B from the measuring tube 2. As already mentioned in the general description, the change in the direction of the magnetic field B does not mean a simple polarity reversal of the magnetic field B, but a change in the direction of the magnetic field B that goes beyond anti-parallelism. Furthermore, by arranging the coils 4 as described above on the circumferential surface of the magnetic field guide device 5 extending in the circumferential direction of the measuring tube, no additional space is required in the direction toward the measuring tube 2 (see FIG. 1), making it possible to achieve a space-saving structure.

[0050] At least three coils 4 ensure that a change of direction (and not just a simple reversal of direction) of the above-mentioned magnetic field B can be realized. At least three measuring electrodes 6 likewise ensure that more than one measurement section can be realized through the cross section of the measuring tube 2. The above-mentioned structural provisions thus essentially allow a variable excitation of the medium over the cross section of the measuring tube 2 and a variable geometrical realization of the measurement section over the cross section of the measuring tube 2, so that a large number of flow information over the cross section of the measuring tube 2 collected in various geometrical surrounding conditions can be detected and, by calculation of these in the flow measurement, a clear independence from the variable flow profile can be achieved.

[0051] 1, the magnetic field guide device 5 forms a substantially circularly shaped, arc-shaped, curved ring, which is relatively easy to realize and, due to its basic nature, does not have any local dependencies arising from the shape, in particular those not related to the entry point into and exit point from the measuring tube 2 of the magnetic field B, which can be influenced by the application of current to the coil.

[0052] 2 shows a schematic representation of another configuration of the magnetoinductive flowmeter 1, in which the relationship of the arrangement of the coils 4 and the measuring electrodes 6 can be better seen according to a cross section through the area of ​​the magnetic field device 3 and the magnetic field guide device 5 and the coils 4 formed thereon. Also, as can be seen essentially according to FIG. 2, the structural configuration (which accordingly presupposes a variable current flow through the coils 4) allows the excitation of the medium with a spatially varying coverage to be realized essentially by a directionally adjustable magnetic field B and also by a directionally variable realization of the measuring section.

[0053] In the embodiment according to Fig. 2, the magnetic field guide device 5 forms a polygonal ring, here an octagonal ring, which has alternating long and short legs, on which the coils 4 are arranged.

[0054] In the exemplary embodiment according to Fig. 2, the coils 4a, 4b are energized in such a way that they generate a magnetic field B in one direction of orientation with respect to the magnetic field guide device 5, and the coils 4c, 4d are energized in such a way that they generate a magnetic field B in the opposite direction of flow with respect to the magnetic field guide device 5. The total magnetic field B flows between the coils 4a, 4c into free space and into the measuring tube 2, passes through the measuring tube 2 and flows again between the coils 4b, 4d into the magnetic field guide device 5. The symbol B is not to be understood here as an arithmetic expression symbol.

[0055] A total of four measuring electrodes 6a, 6a', 6b, 6b' are provided on the wall of the measuring tube 2. Between the measuring electrodes 6, a measuring voltage U can be recorded. In the example shown, a measuring voltage Ua is recorded between the measuring electrodes 6a and 6a'. For the sake of clarity, FIG. 2 does not show that in other operating modes, the current supply to the coil 4 is partially different from the illustrated operating method. In these operating modes, which are not shown, the current supply direction of the coils 4b, 4c is reversed, and thus the direction of the magnetic field generated by the coils 4b, 4c is also reversed with respect to the magnetic field guide device 5. As can be clearly seen, the resulting magnetic field B thus flows between the coils 4c, 4d into the free space and into the measuring tube 2, passes through the measuring tube 2 and again into the magnetic field guide device 5 between the coils 4a, 4b. Of course, it can also happen that the free space magnetic field flows out of the coil 4 directly in the edge region and into the coil 4 directly in the edge region. In this case, however, this is a stray magnetic field which, as mentioned above, accounts for a significant proportion of the magnetic field B. The direction of the magnetic field B can be changed in yet another way, for example by changing the current strength in the coil 4. The orientation of the respective measurement section between the measurement electrodes 6, in which the measurement voltage U is recorded, is not variable, but is set fixedly here by the fixed mounting position of the measurement electrodes 6. In all exemplary embodiments, the measurement electrodes 6 are arranged between the two coils 4 in the radial direction as seen from the center of the measuring tube 2. Furthermore, apart from the advantage that good access to the measurement electrodes 6 (mounting and making electrical contact) is possible, this also has the advantage that, structurally, the measurement path which can be realized by the measurement electrodes 6 is inclined to the extension direction of the magnetic field B which can be generated and thus in each case partially extends in the extension direction of the potential change (induced voltage).

[0056] In Figures 3 to 6 different operating modes are shown, which are mainly related to how the coil 4 is energized to generate a certain magnetic field direction. Each operating mode is also usefully applicable to the magnetoinductive flow measurement device 1 shown diagrammatically in Figures 7 and 8. In this case, the illustrations in Figures 3 to 6 relate to the magnetoinductive flow measurement device 1 shown in Figure 2, which comprises four coils 4a, 4b, 4c, 4d and four measurement electrodes 6a, 6a', 6b, 6b'.

[0057] Common to all magnetoinductive flowmeters 1 shown, the control and evaluation device 7 energizes at least some of the coils 4 in at least one first operating mode M1 such that the generated magnetic field B is oriented in a first operating direction in the area of ​​the measuring tube 2, and energizes at least some of the coils 4 in at least one second operating mode M2 ​​such that the generated magnetic field B is oriented in a second operating direction different from the first operating direction in the area of ​​the measuring tube 2. It should be noted that in this case as well, the direction is mathematically understood, i.e. defined by a straight line with two orientations, a first orientation and an orientation antiparallel to it, i.e. a reversal of the orientation is not a change of direction.

[0058] In the exemplary embodiment shown in Figures 3 to 6, there are in each case two operating modes M1, M2, in which, in conjunction with the structural configuration of the magnetoinductive flowmeter 1 according to Figure 2, a magnetic field B is generated with mutually perpendicular magnetic field directions in the two different operating modes M1, M2. Respective energization graphs 9 are also shown, which represent the energization of the four coils 4a, 4b, 4c, 4d involved with a current I over time. The energization graphs 9 show the magnetic field directions resulting from the respective magnetic field B, which can be easily understood in conjunction with the illustration of the magnetic field device 3 with the coils 4a, 4b, 4c, 4d. The energization graphs 9 show the respective operating modes M1, M2.

[0059] The illustration of the magnetic field device 3 with the measuring tube 2, the coil 4 and the magnetic field guide device 5 also shows the measuring electrodes 6a, 6a' or measuring electrodes 6b, 6b', respectively, which are involved in measuring the measuring voltage U induced in each operating mode M1, M2.

[0060] Similarly, for the magnetic induction flow measuring device 1 partially shown in Figures 3 to 6, the measuring electrodes 6 are arranged between the two coils 4 in the radial direction as viewed from the center of the measuring tube 2 such that a first pair 6a, 6a' of measuring electrodes 6 forms a first measuring section with a first measuring section direction, in which the first measuring section direction and the first operating direction of the magnetic field B are inclined to each other and here also form an angle of 90° to each other, and a second pair 6b, 6b' of measuring electrodes 6 forms a second measuring section with a second measuring section direction, in which the second measuring section direction and the second operating direction of the magnetic field B are also inclined to each other and here also form an angle of 90° to each other.

[0061] In the case of operating mode M1, the measuring electrodes 6a, 6a' record the measuring voltage U, and in the operating mode M2, the measuring electrodes 6b, 6b' record the measuring voltage U. In both cases, the measuring voltage U is perpendicular to the direction of the magnetic field B. This results in a maximum induction effect.

[0062] Similarly for the magnetoinductive flow measuring device 1 of FIGS. 3 to 6, the control and evaluation device 7 performs a first operating mode M1 at least once in order to determine the improved flow measurement value Vp in the measurement sequence MS, in which the first measuring voltage U1 and / or the first flow measurement value Vp1 are determined by means of a first pair of measuring electrodes 6, and performs a second operating mode M2 ​​at least once in which the second measuring voltage U2 and / or the second flow measurement value Vp2 are determined by means of a second pair of measuring electrodes 6, and determines the improved flow measurement value Vp from the first measuring voltage U1 and the second measuring voltage U2 and / or from the first flow measurement value Vp1 and the second flow measurement value Vp2, in particular by averaging. That is to say, in general: Vp=f(U1,U2), or Vp = f(Vp1(U1), Vp2(U2)) holds true.

[0063] Here, f is in particular the average value formation under discussion. As shown in figures 3 to 5, a number of measurement voltages in each operating mode M1, M2 in the measurement sequence MS are also detected. This is because, in the example embodiment, the control and evaluation device 7 executes the first operating mode M1 at least twice (four times in figures 3 to 5) in the measurement sequence MS, whereby a magnetic field B is generated in one orientation of the first operating direction of said magnetic field B and in the other orientation of the first operating direction of the magnetic field B, and by means of the first pair of measurement electrodes 6, corresponding sub-measurement voltages Us1.1, Us1.2 / sub-flow measurement values ​​Vps1.1, Vps1.2 are recorded in each orientation of the first operating direction of the magnetic field B, and from the sub-measurement voltages Us1.1, Us1.2 / sub-flow measurement values ​​Vps1, Vps2 the first flow measurement value Vp1 is determined. and the control and evaluation device 7 executes the second operating mode M2 ​​at least twice in the measurement sequence MS, whereby the magnetic field B is formed in one orientation of the second operating direction of the magnetic field B and in the other orientation of the second operating direction of the magnetic field B, the second pair of measurement electrodes 6 records corresponding sub-measurement voltages Us2.1, Us2.2 / sub-flow measurement values ​​Vps2.1, Vps2.2 in each orientation of the second operating direction of the magnetic field B, and the second flow measurement value Vp2 is calculated from the sub-measurement voltages Us2.1, Us2.2 / sub-flow measurement values ​​Vps2.1, Vps2.2. That is, U1=g(Us1.1,Us1.2),U2=g(Us2.1,Us2.2) Vp1=h(Vp1.1,Vp1.2),Vp2=h(Vp2.1,Vp2.2) holds true.

[0064] The use of multiple measurement voltages Ui in a first direction and a direction antiparallel thereto or in a second direction and a direction antiparallel thereto is only significant in the sense that the method makes it possible to calculate an electrochemical interference voltage that is independent of the magnetic field direction.

[0065] In the magnetic induction flow measuring device 1 according to FIG. 3, it is realized that the control and evaluation device 7 executes the measurement sequence MS at least every time such that the magnetic field B is first formed sequentially in two orientations of the first operating direction, i.e. in operating mode M1 (alternatively in the second operating direction, i.e. in operating mode M2), and then formed sequentially in two orientations of the second operating direction, i.e. in operating mode M2 ​​(alternatively in the first operating direction, i.e. in operating mode M1), whereby the orientations of the operating directions M1, M2 are alternately and sequentially driven and controlled several times, each two times in the present embodiment.

[0066] In the magnetoinductive flowmeter 1 according to FIG. 4, it is provided that the control and evaluation device 7 executes the measurement sequence MS at least periodically, such that the orientation of at least two operating directions (and thus operating modes Mi) of the magnetic field B is successively controlled to generate a magnetic field B which rotates in a stepped manner as seen in the axial direction of the measuring tube 2. In a more interesting aspect of the embodiment, the energization of the coil 4 is furthermore shown here in two alternative implementations. On the one hand, it is shown that the control and evaluation device 7 realizes the change in the energization of the coil 4 as jump-like or rectangular as possible. However, on the other hand, when a series of operating modes Mi is realized, it is also possible for the control and evaluation device 7 to realize the change in the energization of the coil 4 continuously and sinusoidally, which is shown in the same energization graph 9.

[0067] In FIG. 5, the time characteristic of the measured voltage U at the measuring electrode pairs 6a, 6a' and 6b, 6b' is shown as well as the energization graph 9 with the current I applied to the coils 4a, 4c and 4b, 4d. In the voltage characteristic, it can be seen that a linearly increasing electrochemical electrode voltage is superimposed on the induced voltage, which is based on the fact that the flow rate and thus the volumetric flow rate remains unchanged during the period shown. Such electrode voltages can be eliminated by calculation using known measures (for example by detection and calculation of sub-measurement voltage or sub-flow rate measurements). Furthermore, it can be seen that abrupt changes in the energization of the coil 4 act on both detected measurement voltages Ui. Measurement values ​​should therefore only be recorded once such transient disturbances have subsided.

[0068] The magnetoinductive flowmeter 1 according to Fig. 6 is characterized in that the control and evaluation device 7 energizes at least some of the coils 4 in the intermediate operating mode Mint, so that the magnetic field B formed is oriented in an intermediate operating direction in the area of ​​the measuring tube 2, the intermediate operating direction being oriented differently from the first operating direction in the first operating mode M1 and from the second operating direction in the second operating mode M2 ​​and possibly from further operating directions. In this case, fewer coils 4 are energized in the intermediate operating mode Mint when forming the magnetic field B in the intermediate operating direction than in the energization for forming the magnetic field B in the operating modes M1, M2.

[0069] In a magnetic induction flow measuring device 1 not explicitly mentioned here, the control and evaluation device 7 passes currents of different magnitudes through at least some of the coils 4 in at least one intermediate operating mode Mint, as a result of which the magnetic field B formed is oriented in an intermediate operating direction in the area of ​​the measuring tube 2, where the intermediate operating direction is an operating direction different from the first operating direction in the first operating mode M1 and the second operating direction in the second operating mode M2 ​​and possibly other operating directions, and when forming the magnetic field B in the intermediate operating direction, it is realized that, in particular, fewer coils 4 are passed through than in the case of current passing for forming the magnetic field B in each operating direction.

[0070] The realization of an intermediate operating mode Mint is significant if the control and evaluation device 7 not only determines the measurement voltage Ui / flow measurement value Vpi from at least the first operating mode M1 and at least the second operating mode M2 ​​by means of the pair of measuring electrodes 6 in order to determine the improved flow measurement value Vp in the measurement sequence MS, but also determines at least one intermediate measurement voltage Uint / intermediate flow measurement value Vpint in the intermediate operating mode Mint and determines the improved flow measurement value Vp from the first measurement voltage U1 / first flow measurement value Vp1 and the second measurement voltage U2 / second flow measurement value Vp2 and the intermediate measurement voltage Uint / intermediate flow measurement value Vpint, in particular by averaging. Thus, Vp = i(U1,U2,Uint) Vp = i (Vp1, Vp2, Vpint) holds true.

[0071] 7 shows two magnetoinductive flowmeters 1 with exactly three measuring electrodes 6a, 6b, 6c, which are arranged at an angle of approximately 120° to one another when viewed from the center of the measuring tube 2. In the left-hand example, exactly three coils 4a, 4b, 4c are likewise arranged at an angle of approximately 120° to one another and at an angle of approximately 60° to the measuring electrodes 6a, 6b, 6c. To generate the magnetic field B in the three operating directions, the control and evaluation device 7 energizes two of the coils 4 for each operating direction, in particular in such a way that an opposing magnetic field B is generated relative to the magnetic field guide device 5. The possible magnetic field directions are shown to the left of FIG. 7 along with the direction of the measurement section that can be realized. In other words, multiple geometrically differently distributed flow information is obtained through the cross section of the measuring tube 2, so that when calculating the flow measurement value Vp, the flow measurement value Vp is calculated essentially independent of the true flow profile, depending on all the flow information (measurement voltages or sub-flow measurement values) obtained over the respective different measurement sections.

[0072] The magnetoinductive flowmeter 1 shown on the right side of Fig. 7 likewise has exactly three measuring electrodes 6a, 6b, 6c, which are arranged at an angle of approximately 120° to one another as viewed from the center of the measuring tube 2. However, six coils 4a, 4a', 4b, 4b', 4c, 4c' are provided, such that, as viewed from the center of the measuring tube 2, each of the two coils 4a, 4a'; 4b, 4b'; 4c, 4c' of the six coils 4a, 4a', 4b, 4b', 4c, 4c' has between it one measuring electrode 6a, 6b, 6c, and each of the two measuring electrodes 6a, 6b; 6b, 6c; 6c, 6a has between them two coils 4a', 4b; 4b', 4c; 4c', 4a. Of the six coils 4a, 4a', 4b, 4b', 4c, 4c', three coils 4a, 4b, 4c; 4a', 4b', 4c' are arranged at an angle of approximately 120° to each other, and the two coils 4a, 4a'; 4b, 4b'; 4c, 4c' arranged adjacent to each measuring electrode 6a, 6b, 6c are arranged at the same angle to the measuring electrodes 6a, 6b, 6c. Only one current-carrying situation is shown on the right side of FIG. 7 for clarity. In general, to generate the magnetic field B, the control and evaluation device 7 causes current to flow through the four coils 4a, 4a', 4b, 4b', 4c, 4c' in the direction of movement, here the coils 4a, 4a', 4b, 4b', 4c, 4c' arranged symmetrically with respect to the axis of the direction of movement. In this embodiment, current is applied to the coils 4a, 4a' and 4b, 4b'. The measurement voltage U is recorded between the measurement electrodes 6a, 6b across the measurement section. In the other two operating modes, it is advantageously always the case that four coils are energized and sub-measurement voltages are recorded that are located in the measurement section perpendicular to the operating direction of the magnetic field B. In general, three measurement sections are realized by three measurement electrodes 6a, 6b, 6c, in which case the control and evaluation device 7 generates three magnetic fields B with different operating directions in each of the three operating modes, executes all three operating modes in a measurement sequence MS, obtains three measurement voltages Ui / three flow rate measurements Vpi from the three measurement sections and obtains the improved flow rate measurement Vp from the three measurement voltages Ui / three flow rate measurements Vpi.

[0073] In FIG. 8 a magnetoinductive flowmeter 1 is shown which has exactly four measuring electrodes 6a, 6b, 6c, 6d.

[0074] On the left side of FIG. 8, the configuration is shown which is basically already known from FIG. 2. The four measuring electrodes 6a, 6b, 6c, 6d are arranged at an angle of approximately 90° to one another when viewed from the center of the measuring tube 2. The four coils 4a, 4b, 4c, 4d are arranged at an angle of approximately 90° to one another. Furthermore, the four coils 4a, 4b, 4c, 4d are arranged at an angle of 45° to the measuring electrodes 6a, 6b, 6c, 6d, respectively. To generate a magnetic field B in the two operating directions, the control and evaluation device 7 energizes all four coils 4a, 4b, 4c, 4d for each operating direction. The case shown is one in which a magnetic field B is generated in the vertical direction.

[0075] On the right side of Figure 8, one configuration of a magnetoinductive flow measuring device is shown which has exactly four measuring electrodes 6a, 6b, 6c, 6d, which are arranged at an angle of 90° to each other when viewed from the center of the measuring tube 2. Here, eight coils 4a, 4a', 4b, 4b', 4c, 4c', 4d, 4d' are provided, and of the eight coils 4a, 4a', 4b, 4b', 4c, 4c', 4d, 4d', two coils 4a, 4a'; 4b, 4b'; 4c, 4c'; 4d, 4d' have one measuring electrode 6a; 6b; 6c; 6d between them, as viewed from the center of the measuring tube 2, and two measuring electrodes 6a, 6b; 6b, 6c; 6c, 6d; 6d, 6a have two coils 4a', 4b; 4b', 4c; 4c', 4d; 4d', 4a between them, respectively. Of the eight coils 4a, 4a', 4b, 4b', 4c, 4c', 4d, 4d', four of the coils 4a, 4b, 4c, 4d; 4a', 4b', 4c', 4d' are arranged at an angle of 90° to each other, and two coils 4a, 4a'; 4b, 4b'; 4c, 4c'; 4d, 4d' arranged adjacent to one measurement electrode 6a, 6b, 6c, 6d are arranged at the same angle to the measurement electrodes 6a, 6b, 6c, 6d, respectively. This configuration shows a very high degree of symmetry.

[0076] The magnetoinductive flowmeter 1 shown on the right side of Fig. 8 is characterized in that at least four coils 4, i.e. coils 4 that are symmetrically positioned with respect to the axis of the direction of movement, are energized by the control and evaluation device 7 in order to generate a magnetic field B in the direction of movement. In this example, a vertical direction of movement of the magnetic field B is shown, which is generated by energizing the coils 4a, 4a', 4c, 4c'.

[0077] When designing the magnetoinductive flowmeter 1 shown on the right in Fig. 8, it is taken into account that in order to generate a magnetic field B in the direction of movement, the control and evaluation device 7 energizes exactly four coils 4 that are symmetrically positioned with respect to the axis of the direction of movement and that are furthest away from the axis of the direction of movement. In this way, a wide magnetic field B that penetrates most of the cross section of the measuring tube 2 can be generated. [Explanation of symbols]

[0078] 1. Magnetic induction type flow measuring device 2 Measuring tube 3 Magnetic field device 4 Coils 5. Magnetic field guide device 6 Measuring electrode 7 Control and evaluation device 8 Flanges 9 Power status graph B magnetic field U Measurement voltage M1,M2 operation mode Us sub measurement voltage Usi i-th sub-measurement voltage Uint Intermediate measurement voltage Vp Flow measurement Vpi i-th flow measurement value Vps Sub-flow measurement value Vpsi i-th sub-flow measurement value Vpint Intermediate flow rate measurement MS measurement sequence

Claims

1. A magnetic induction type flow measuring device (1), wherein the magnetic induction type flow measuring device (1) is A measuring tube (2) that guides the conductive medium, A magnetic field device (3) having a plurality of coils (4) that form a magnetic field (B) that penetrates the measuring tube (2) at least partially perpendicular to the flow direction of the medium, and a magnetic field guide device (5) that guides the magnetic field (B) in regions outside the measuring tube (2), A measuring electrode (6) for extracting at least one measuring voltage (U) induced in the medium, A control and evaluation device (7) that forms a magnetic field (B) by energizing at least one of the coils (4) and evaluates the measured voltage (U) relative to the flow rate measurement value (Vp), Equipped with, The magnetic field guide device (5) extends so as to enclose the measuring tube (2) in the circumferential direction, The coils (4) are distributed across the circumferential surface of the magnetic field guide device (5), and the magnetic field guide device (5) acts as a coil core within the region of the coils (4), thereby arranging the coils (4) so ​​that their longitudinal axis is similarly in the circumferential direction of the measuring tube (2). At least three coils (4a, 4b, 4c) and at least three measuring electrodes (6a, 6b, 6c) are provided, and each of the measuring electrodes (6a, 6b, 6c) is positioned radially between two coils (4a, 4b, 4c) when viewed from the center of the measuring tube (2). Magnetic induction type flow measuring device (1).

2. The magnetic field guide device (5) forms an arc-shaped curved ring, and in particular, the ring is formed in a circular or elliptical shape in at least one region, or The magnetic field guide device (5) forms a polygonal ring, and in particular, the ring forms a hexagonal or octagonal polygon, preferably having alternating long legs and short legs, and preferably the coil (4) is positioned on the long legs. The magnetic induction type flow measuring device (1) according to claim 1.

3. The control evaluation device (7) energizes at least a portion of the coil (4) in at least one first operating mode (M1) such that the magnetic field (B) formed in the region of the measuring tube (2) is oriented in a first operating direction, and energizes at least a portion of the coil (4) in at least one second operating mode (M2) such that the magnetic field (B) formed in the region of the measuring tube (2) is oriented in a second operating direction (M2) different from the first operating direction (M1). The magnetic induction type flow measuring device (1) according to claim 1.

4. The control evaluation device (7) energizes the plurality of coils (4) in at least the first operating direction and the second operating direction in order to form a magnetic field (B). The magnetic induction type flow measuring device (1) according to claim 3.

5. The control evaluation device (7) either realizes the change in current supply to the coil (4) as a leap as possible, or realizes the change in current supply to the coil (4) in a sinusoidal manner, and in particular realizes a continuously sinusoidal current characteristic. The magnetic induction type flow measuring device (1) according to claim 3.

6. The control evaluation device (7) energizes the coil such that the entire implemented magnetic circuit, particularly the magnetic field device (3) and the magnetic field guide device (5), operates in the linear region and, in particular, the magnetic saturation region is avoided. The magnetic induction type flow measuring device (1) according to claim 3.

7. The measuring electrode (6) is At least one first pair (6a, 6a') of the measuring electrodes (6) forms a first measuring section having a first measuring section direction, and the first measuring section direction and the first operating direction of the magnetic field (B) are inclined toward each other, preferably by more than 45°, and most preferably by 90°. At least one second pair (6b, 6b') of the measuring electrode (6) forms a second measuring section having a second measuring section direction, and the second measuring section direction and the second operating direction of the magnetic field (B) are inclined toward each other, preferably by more than 45°, and most preferably by 90°. As shown above, the measuring tube (2) is positioned radially between the two coils (4) when viewed from the center, The magnetic induction type flow measuring device (1) according to claim 3.

8. The control evaluation device (7) calculates the improved flow rate measurement value (Vp) in the measurement sequence (MS), The first operating mode (M1) is performed at least once, and in the first operating mode (M1), the first measuring voltage (U1) and / or the first flow rate measurement value (Vp1) are calculated using the first pair of measuring electrodes (6). The second operating mode (M2) is performed at least once, and in the second operating mode (M2), the second measurement voltage (U2) and / or the second flow rate measurement value (Vp2) are calculated using the second pair of measuring electrodes (6). An improved flow rate measurement value (Vp) is calculated from the first measured voltage (U1) and the second measured voltage (U2) and / or from the first flow rate measurement value (Vp1) and the second flow rate measurement value (Vp2), particularly by averaging. The magnetic induction type flow measuring device (1) according to claim 7.

9. The control evaluation device (7) executes the first operating mode (M1) at least twice in the measurement sequence (MS), thereby forming a magnetic field (B) in one orientation and the other orientation of the first operating direction of the magnetic field (B), and in each orientation of the first operating direction of the magnetic field (B), the first pair of measuring electrodes (6) records the corresponding sub-measurement voltages (Us1.1, Us1.2) / sub-flow measurement values ​​(Vps1.1, Vps1.2), and the first flow measurement value (Vp1) is calculated from the sub-measurement voltages (Us1.1, Us1.2) / sub-flow measurement values ​​(Vps1.1, Vps1.2). The control evaluation device (7) executes the second operating mode (M2) at least twice in the measurement sequence (MS), thereby forming a magnetic field (B) in one orientation and the other orientation of the second operating direction of the magnetic field (B), and in each orientation of the second operating direction of the magnetic field (B), the second pair of measuring electrodes (6) records the corresponding sub-measurement voltages (Us2.1, Us2.2) / sub-flow measurement values ​​(Vps2.1, Vps2.2), and the second flow measurement value (Vp2) is calculated from the sub-measurement voltages (Us2.1, Us2.2) / sub-flow measurement values ​​(Vps2.1, Vps2.2). The magnetic induction type flow measuring device (1) according to claim 8.

10. The control evaluation device (7) performs the measurement sequence (MS) at least every hour, First, a magnetic field (B) is formed sequentially in two directions, either the first or second direction of operation. Next, the two orientations of the second or first operating direction are sequentially formed, and in particular, the orientation of the operating direction is sequentially driven and controlled multiple times alternately. Execute in this way The magnetic induction type flow measuring device (1) according to claim 9.

11. The control evaluation device (7) executes the measurement sequence (MS) at least every hour such that the orientation of each of the at least two operating directions of the magnetic field (B) is sequentially driven and controlled to generate a magnetic field (B) that rotates in a stepwise manner when viewed in the axial direction of the measuring tube (2). The magnetic induction type flow measuring device (1) according to claim 9.

12. The control evaluation device (7) energizes at least a portion of the coil (4) such that in at least one intermediate operating mode (Mint) the magnetic field (B) formed is oriented in the intermediate operating direction within the region of the measuring tube (2), and the intermediate operating direction is oriented differently from the first operating direction in the first operating mode (M1), the second operating direction in the second operating mode (M2), and possibly another operating direction. In particular, when forming the magnetic field (B) in the intermediate operating direction, fewer coils (4) are energized than when energizing to form the magnetic field (B) in the operating direction. The magnetic induction type flow measuring device (1) according to claim 3.

13. The control evaluation device (7) energizes at least a portion of the coil (4) with currents of different magnitudes in at least one intermediate operating mode (Mint) such that the magnetic field (B) formed is oriented in the intermediate operating direction within the region of the measuring tube (2), and the intermediate operating direction is oriented differently from the first operating direction in the first operating mode (M1), the second operating direction in the second operating mode (M2), and possibly another operating direction. In particular, when forming the magnetic field (B) in the intermediate operating direction, fewer coils (4) are energized than when energizing to form the magnetic field (B) in the operating direction. The magnetic induction type flow measuring device (1) according to claim 3.

14. The control evaluation device (7) calculates the improved flow rate measurement value (Vp) in the measurement sequence (MS), The first operating mode (M1) is performed at least once, and in the first operating mode (M1), the first measuring voltage (U1) and / or the first flow rate measurement value (Vp1) are calculated using the first pair of measuring electrodes (6). The second operating mode (M2) is performed at least once, and in the second operating mode (M2), the second measurement voltage (U2) and / or the second flow rate measurement value (Vp2) are calculated using the second pair of measuring electrodes (6). From the first measured voltage (U1) and the second measured voltage (U2) and / or from the first flow rate measurement value (Vp1) and the second flow rate measurement value (Vp2), an improved flow rate measurement value (Vp) is calculated, particularly by averaging. The control evaluation device (7) calculates the improved flow rate measurement value (Vp) in the measurement sequence (MS), In addition to calculating the measured voltage (Ui) / flow rate measurement value (Vpi) from at least the first operating mode (M1) and at least the second operating mode (M2), at least one intermediate measured voltage (Uint) / intermediate flow rate measurement value (Vpint) is calculated in the intermediate operating mode (Mint) using the pair of measuring electrodes (6). From the first measured voltage (U1) / first flow rate measurement value (Vp1), the second measured voltage (U2) / second flow rate measurement value (Vp2), and the intermediate measured voltage (Uint) / intermediate flow rate measurement value (Vpint), an improved flow rate measurement value (Vp) is calculated, particularly by averaging. The magnetic induction type flow measuring device (1) according to claim 12.

15. The three measuring electrodes (6a, 6b, 6c) are arranged symmetrically in the measuring tube (2) at angles of 90° to 150° relative to each other, particularly at angles of 120° relative to each other, when viewed from the center of the measuring tube (2). The three coils (4a, 4b, 4c) are arranged symmetrically at angles of 90° to 150° relative to each other, particularly at angles of 120° relative to each other, and at angles of 40° to 80° relative to the measuring electrodes (6a, 6b, 6c), particularly at angles of 60°. In order to form a magnetic field (B) in three operating directions, the control evaluation device (7) energizes two of the coils (4) for each operating direction. The magnetic induction type flow measuring device (1) according to claim 1.

16. The three measuring electrodes (6a, 6b, 6c) are arranged symmetrically in the measuring tube (2) at angles of 90° to 150° relative to each other, particularly at angles of 120° relative to each other, when viewed from the center of the measuring tube (2). The six coils (4a, 4a', 4b, 4b', 4c, 4c') are arranged such that, when viewed from the center of the measuring tube (2), two of the six coils (4a, 4a'; 4b, 4b'; 4c, 4c') have one measuring electrode (6a, 6b, 6c) in between, and two measuring electrodes (6a, 6b; 6b, 6c; 6c, 6a) each have two coils (4a', 4b; 4b', 4c; 4c', 4a) in between. Preferably, three of the six coils (4a, 4a', 4b, 4b', 4c, 4c') are arranged at an angle of 120° to each other, and both coils (4a, 4a'; 4b, 4b'; 4c, 4c') adjacent to one measuring electrode (6a, 6b, 6c) are arranged at the same angle to the measuring electrode (6a, 6b, 6c). The magnetic induction type flow measuring device (1) according to claim 1.

17. In order to form a magnetic field (B) in one direction of operation, the control evaluation device (7) energizes at least four coils (4a, 4a', 4b, 4b', 4c, 4c'), preferably energizing coils (4a, 4a', 4b, 4b', 4c, 4c') that are symmetrically positioned with respect to the axis of the direction of operation. The magnetic induction type flow measuring device (1) according to claim 16.

18. Three measurement intervals are realized by the three measuring electrodes (6a, 6b, 6c). The control evaluation device (7) forms three magnetic fields having different operating directions in each of the three operating modes, performs all three operating modes in the measurement sequence (MS), obtains three measurement voltages (Ui) and three flow rate measurement values ​​(Vpi) from the three measurement intervals, and obtains an improved flow rate measurement value (Vp) from the three measurement voltages (Ui) and three flow rate measurement values ​​(Vpi). The magnetic induction type flow measuring device (1) according to claim 15.

19. The four measuring electrodes (6a, 6b, 6c, 6d) are arranged symmetrically in the measuring tube (2) at angles of 70° to 110° relative to each other, and particularly at angles of 90° relative to each other, when viewed from the center of the measuring tube (2). The four coils (4a, 4b, 4c, 4d) are precisely positioned symmetrically at angles of 70° to 110° to each other, particularly at angles of 90° to each other, and at angles of 35° to 55° to the measuring electrodes (6a, 6b, 6c, 6d), particularly at angles of 45°. In particular, in order to form a magnetic field (B) in two operating directions, the control evaluation device (7) energizes all four coils (4a, 4b, 4c, 4d) for each operating direction. The magnetic induction type flow measuring device (1) according to claim 1.

20. The four measuring electrodes (6a, 6b, 6c, 6d) are arranged symmetrically in the measuring tube (2) at angles of 70° to 110° relative to each other, and particularly at angles of 90° relative to each other, when viewed from the center of the measuring tube (2). The eight coils (4a, 4a', 4b, 4b', 4c, 4c', 4d, 4d') are arranged such that, when viewed from the center of the measuring tube (2), each of the eight coils (4a, 4a'; 4b, 4b'; 4c, 4c'; 4d, 4d') has one measuring electrode (6a; 6b; 6c; 6d) between them, and each of the two measuring electrodes (6a, 6b; 6b, 6c; 6c, 6d; 6d, 6a) has two coils (4a', 4b; 4b', 4c; 4c', 4d; 4d', 4a) between them. Preferably, four of the eight coils (4a, 4a', 4b, 4b', 4c, 4c', 4d, 4d') are arranged at a 90° angle to each other, and both coils (4a, 4a'; 4b, 4b'; 4c, 4c'; 4d, 4d') adjacent to one measuring electrode (6a, 6b, 6c, 6d) are arranged at the same angle to the measuring electrode (6a, 6b, 6c, 6d). The magnetic induction type flow measuring device (1) according to claim 1.

21. In order to form a magnetic field (B) in one direction of operation, the control evaluation device (7) energizes at least four coils (4), preferably coils (4) positioned symmetrically with respect to the axis of the direction of operation. The magnetic induction type flow measuring device (1) according to claim 20.

22. In order to form a magnetic field (B) in one direction of operation, the control evaluation device (7) energizes four coils (4) precisely, in particular the four coils (4) that are symmetrically positioned with respect to the axis of the direction of operation and are furthest from the axis of the direction of operation. The magnetic induction type flow measuring device (1) according to claim 21.

23. The control evaluation device (7) calculates the volumetric flow rate of the medium from a linear combination of multiple measured voltages (Ui) among the detected measured voltages (Ui), and in particular, the measured voltages (Ui) are weighted by a weighting coefficient. A magnetic induction type flow measuring device (1) according to any one of claims 1 to 22.

24. The control evaluation device (7) calculates the volumetric flow rate (Vp) of the medium using a nonlinear function at multiple measured voltages (Ui) among the detected measured voltages (Ui). A magnetic induction type flow measuring device (1) according to any one of claims 1 to 22.

25. The aforementioned nonlinear function is formed by an artificial neural network having an input layer having at least a plurality of input neurons corresponding to the number of detected measured voltages (Ui) as input parameters, an output layer having at least one output neuron that outputs at least the volumetric flow rate (Vp) of the medium as an output parameter, and at least one hidden layer having at least two neurons. In particular, the artificial neural network is trained using calibration data. The magnetic induction type flow measuring device (1) according to claim 24.

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