Magnetic inductive flow measuring device and method for determining the fill level

Abstract

The invention relates to a magnetic-inductive flow measuring device, in particular a magnetic-inductive flow measuring probe, comprising: a housing (2); at least one measuring electrode (3, 4) for making electrical contact with a medium and for tapping an induced voltage in the medium; a device for generating a magnetic field, wherein the device is arranged in the housing (2), wherein the device comprises a field guiding assembly (5) and a coil arrangement (6), wherein the field guiding assembly (5) serves as a sensor electrode for capacitively determining and / or monitoring at least one process variable, in particular a level of a medium in a measuring tube or a pipeline. The invention also relates to a method for determining a level of a medium in a measuring tube or a pipeline using a magnetic-inductive flow measuring device according to the invention.

Description

Technical Field

[0001] This invention relates to a magnetic induction flow measurement device for determining the velocity-related measured variable of a flowable medium in a measuring tube or pipeline, and to a method for determining the level of the medium in a measuring tube or pipeline. Background Technology

[0002] Magnetic induction flow measurement devices include meters that detect the measured variable, which is related to the flow rate of a medium relative to a meter, based on Faraday's law of electromagnetic induction. Magnetic induction flow measurement devices include, for example, a magnetic induction flow meter through which the medium to be monitored flows and / or a magnetic induction flow measurement probe used in a pipeline through which the medium flows.

[0003] A magnetic induction flow meter includes a measuring tube for guiding a flowable medium and is used to determine the flow rate and volumetric flow rate of the medium entering a process pipeline. The magnetic induction flow meter has a device for generating a magnetic field that passes through the measuring tube perpendicular to the flow direction of the flowing medium. For this purpose, individual coils are typically used, which together form a coil assembly. To achieve a uniformly dominant magnetic field, pole shoes are formed and attached in addition to the coil core, such that the magnetic field lines extend substantially perpendicular to the horizontal axis of the measuring tube or parallel to the vertical axis across the entire tube cross-section. A measuring electrode assembly attached to the side surface of the measuring tube taps an electrical measurement voltage or potential difference perpendicular to the flow direction and induced by the magnetic field, generated when a conductive medium flows in the flow direction in which the magnetic field is applied. Because, according to Faraday's law of induction, the tapped measurement voltage depends on the velocity of the flowing medium, the flow rate u, and the volumetric flow rate V, the voltage U can be determined from the inductive measurement using the known pipe cross-section.

[0004] Compared to magnetic induction flowmeters, which include an attachment device for generating a magnetic field penetrating the measuring tube and a measuring electrode conductive medium, magnetic induction flowmeter probes are inserted into a lateral opening of the pipeline and fixed in a fluid-tight manner with their typically cylindrical housing. Special measuring tubes are no longer required. The measuring electrode assembly and coil assembly on the side surface of the measuring tube mentioned in the description are omitted and replaced by a device for generating the magnetic field, which is arranged inside the housing and directly close to the measuring electrodes, and is designed such that the axis of symmetry of the magnetic field lines of the generated magnetic field intersects perpendicularly with the front surface or the surface between the measuring electrodes. Various different magnetic induction flowmeter probes already exist in the prior art.

[0005] For example, EP 0 892 251 A1 teaches a magnetic induction flow measurement probe having a front plate designed as a spherical cap and a coil pushed onto a cylindrical coil core that serves as a coil carrier. To date, no magnetic induction flow measurement probe is known designed for detecting the complete and / or partial filling of a pipeline. Instead, this functionality is known in magnetic induction flow meters.

[0006] For example, WO 2014 / 053324 A2 teaches a magnetic induction flowmeter with a level monitoring system that, apart from the distinction between partial and full filling, allows the determination of the medium temperature using a temperature sensor integrated into the level electrode, while also being characterized by its compact structure. To monitor the level, the conductivity of the medium between the level monitoring electrode and the reference or measuring electrode is determined. For this purpose, the level monitoring electrode needs to form electrical contact with the medium to be conducted. This is disadvantageous, therefore an additional opening for the level monitoring electrode must be provided in the measuring tube, and the level monitoring electrode is thus exposed to the potentially abrasive and corrosive medium without protection.

[0007] A device for determining the level of material in a measuring tube is known from DE 196 15 140 A1. The device is configured to use two capacitor plates attached to the outer surface of the measuring tube to determine the capacitance, which depends on the dielectric constant of the medium and the filling height, and to determine the filling height based on the determined capacitance.

[0008] DE 10 2012 006 891 A1 teaches a magnetic induction flowmeter that determines the degree of filling in addition to the measured variable related to flow velocity. For this purpose, it has an additional magnetic field generating device that generates a magnetic field whose magnetic field lines extend parallel to the longitudinal axis of the measuring tube. The measuring voltage caused by the additional magnetic field on the strip measuring electrode is a measure of the medium level. Summary of the Invention

[0009] The purpose of this invention is to provide an alternative magnetic induction flow measurement device suitable for providing information about the level of a medium.

[0010] In addition, the purpose of this invention is to provide an alternative method for magnetic induction flow measurement equipment, which can determine the level of the medium.

[0011] This objective is achieved by the magnetic induction flow measurement device according to the invention and the method for determining the material level according to the invention.

[0012] The magnetic induction flow measurement device according to the present invention for determining the velocity-related measured variable of a flowable medium in a measuring pipe or pipeline includes: - Casing; - A device for tapping voltages induced in a medium, particularly for forming an electrical contact with the medium at least one measuring electrode; - Devices used to generate magnetic fields The device is housed within a casing. The device includes a field guiding assembly and a coil assembly. The field guiding component serves as a sensor electrode for capacitively determining and / or monitoring the level of at least one process variable, particularly the medium in a pipeline or measuring tube.

[0013] A field guiding assembly is used to amplify and guide the magnetic field generated by a coil assembly. It includes at least one field guide, such as a coil core, arranged within the coil of the coil assembly. Additionally, pole shoes are often used to ensure that the magnetic field lines extend parallel to the largest possible cross-sectional area of ​​the measuring tube or pipeline as they leave the coil core. Furthermore, magnetic induction flow measurement devices are known to use field return bodies to guide the generated magnetic field back to the coil core in a controlled manner. The field guide can be monolithic or partially monolithic. For example, it is known to form the coil core and pole shoes integrally, wherein the portion extending through the opening of the coil is called the coil core, and the portion extending along the medium direction between the coil and the housing wall or measuring tube wall is called the pole shoe. The various components of the field guide typically comprise a soft magnetic material. According to the invention, a conductive material is used for the field guide.

[0014] Capacitive level gauges are known to determine the level of a medium in a container by starting with a determined capacitance or a change in capacitance. For this purpose, capacitive level gauges have a sensor electrode arranged together with a conductive counter electrode within a housing having an electrically insulating wall, typically the metal wall of the container, forming a capacitor. A distinction is made between applications using conductive and non-conductive media. The conductive medium in electrical contact with the counter electrode assumes the potential of the counter electrode, such that an electric field is essentially formed within the electrically insulating wall of the housing. If a non-conductive medium is located between the sensor electrode and the counter electrode, an electric field is formed within the medium, whereby the dielectric constant of the medium significantly affects the determined capacitance.

[0015] Capacitive metering is known in the prior art and is manufactured by the applicant in various different designs and sold under names such as Liquicap, Solicap, or Liquipoint. Capacitive meters typically have a generally cylindrical housing with at least one sensor electrode that can be at least partially introduced into a container or pipeline. Rod-shaped meters extending vertically into the container are widely used, particularly for continuous level measurement. However, meters that can be introduced into the sidewall of the corresponding container for detecting limit levels are also known.

[0016] The field guiding component has a conductive field guide. This allows the field guiding component to be used for unintended purposes and configured as a sensor electrode that determines a measurement capacitance based on its ability to indicate the level of the medium in a pipeline or measuring tube. In this case, the medium acts as a counter electrode or dielectric.

[0017] This invention is applicable to continuous monitoring and / or determination of material level, including determining the current filling height, or determining whether a binary state exists or which binary state exists, i.e., fully filled or partially filled.

[0018] To determine the volumetric flow rate, the determined flow rate is multiplied by the cross-sectional area of ​​the measuring tube or pipeline. However, this only applies when the measuring tube is full. Therefore, it is advantageous that magnetic induction flow measurement devices are also designed to indicate whether there is partial or complete filling.

[0019] Field devices in the form of multiple sensors are known. Therefore, meters capable of operating in both capacitive and conductive modes exist. Examples are disclosed in documents DE 10 2011 004 807 A1, DE 10 2013 102 055 A1, or DE 102014 107 927 A1. In addition to the level as a process variable, various media-specific properties, such as the conductivity of the medium, or the dielectric properties of the medium, such as its dielectric constant, can be determined by such multiple sensors, as described in DE 10 2013 104 781 A1. The difference between such meters and the subject matter of this invention lies particularly in that the measuring electrodes are used to determine the conductivity of the medium, rather than to determine the induced measurement voltage according to the invention. Furthermore, such meters lack a device for generating a magnetic field, which is essential for determining the measured variable related to flow rate according to Faraday's law of electromagnetic induction.

[0020] The measured variables related to flow rate include flow rate, volumetric flow rate, and / or mass flow rate.

[0021] Advantageous embodiments of the present invention are as follows.

[0022] One embodiment specifies that the operating circuitry, particularly arranged within the housing, is electrically connected to the field guiding assembly. The operating circuit is configured to supply, in particular, time-alternating excitation signals to the field guiding component, receive response signals from the field guiding component, and indicate the level of the medium in the pipeline or measuring tube based at least on the response signals.

[0023] During measurement, the sensor electrodes are supplied with an excitation signal, typically in the form of an AC signal or AC voltage signal. This is set by the operating circuitry. The corresponding process variable, i.e., the current material level or whether full filling exists, can then be determined based on the response signal received from the sensor electrode or a further sensor electrode designed and configured for this purpose. Based on the principle of capacitance measurement, the dependence of the response signal on the capacitance of a capacitor formed by the sensor electrode and the container wall, or a capacitor formed by the sensor electrode and a second electrode, is utilized. The dielectric of this capacitor is formed by the medium itself or the insulating layer of the sensor electrode, depending on the conductivity of the medium.

[0024] For example, to evaluate the response signal received from the sensor electrodes regarding the material level, it is possible to perform an apparent current measurement or an admittance measurement. In the case of apparent current measurement, the magnitude of the apparent current determined at the sensor electrodes is measured. However, since the apparent current itself has active and reactive components, in the case of admittance measurement, in addition to the apparent current, the phase angle between the apparent current and the voltage applied to the sensor unit is also measured. Another possibility for determining the material level is to determine the frequency shift between a reference signal and a response signal, where the reference signal is determined in a regulation method, such as a plant regulation method.

[0025] Furthermore, the additional determination of the phase angle makes it possible to describe possible accretion formations, for example, as known from DE102004008125A1.

[0026] The operating circuitry is responsible for the feeding, acquisition, and evaluation of signals and is designed accordingly. It can be configured to perform specific operations, including control structures, to provide excitation signals and determine response signals. In certain embodiments, the operating circuitry forms part of a processing subsystem that includes one or more computing devices with memory, processing, and / or communication hardware. The operating circuitry can be a single unit or multiple units that communicate with each other. The functionality of the operating circuitry can be executed via hardware and / or software. The operating circuitry may include one or more arithmetic logic units (ALUs), central processing units (CPUs), memory, limiters, regulators, filters, oscillators, format converters, etc., not shown for clarity. In one form, the operating circuitry can be programmed to execute algorithms and process data according to operating logic defined by programming instructions such as software or firmware. Alternatively or additionally, the operating logic of the operating circuitry can be defined at least in part by hard-wired logic or other hardware, such as by any suitable type of application-specific integrated circuit (ASIC). It must be considered that the operating circuit can be specifically used to generate excitation signals and determine response signals, or it can also be used for the regulation, control and activation of one or more other subsystems or aspects of the magnetic induction flow measurement device.

[0027] One embodiment specifies that the magnetic induction flow measurement device includes a magnetic induction flow measurement probe for insertion into a pipeline through which the medium can flow. The magnetic induction flow measurement probe has a housing, which is specifically cylindrical and configured to be supplied with a medium. The housing has an end, which includes at least partially electrically insulating walls. At least one measuring electrode is arranged in the wall of the housing. The device used to generate the magnetic field is configured to generate a magnetic field at the penetrating end.

[0028] A magnetic induction flow measurement probe has a housing configured and suitable for supplying a medium to be conducted. This means the housing is in contact with the medium during operation, unlike a magnetic induction flow meter. Typically, the generally cylindrical housing of a magnetic induction flow measurement probe has a cavity in which the device for generating the magnetic field, electrical conductors, and, for application-related reasons, operating, measuring, and / or evaluation circuitry are arranged. The housing can also be formed or entirely cast, in which the electrical conductors, at least one measuring electrode, and the device for generating the magnetic field are co-cast. The housing is typically at least partially cylindrical or hollow cylindrical, but can also be partially cuboid for application-related reasons. The medium-contact housing is typically designed to be conductive, for example, made of metal or metallized material, and serves as a reference electrode. However, magnetic induction flow measurement probes in which the reference electrode is designed as a ring electrode, or in which the medium to be conducted is connected to a reference potential via a connector, are also known.

[0029] According to an advantageous embodiment, the housing has a precursor at the media contact end face, which closes the cavity of the housing. This precursor is preferably at least partially disc-shaped. The precursor seals the interior of the housing against the flowing medium in the pipeline. At least one measuring electrode is arranged in the precursor.

[0030] The magnetic induction flow measurement probe is inserted into the opening of the tube, so that the front of the housing is in direct contact with the medium to be conducted.

[0031] To detect the velocity-dependent variable induced in a medium, a measuring electrode device is required, particularly at least one measuring electrode combined with a reference electrode, electrically connected to a reference potential, especially a ground potential. This reference electrode can be implemented, for example, as a needle electrode, a ring electrode, or even as a partially metal housing connected to, for example, a grounded reference potential. However, commercially available magnetic induction flow measurement probes have two measuring electrodes arranged on a measuring electrode shaft and on the medium contact end face of the precursor, wherein the magnetic induction flow measurement probe is positioned in the opening of the pipe such that the measuring electrode shaft preferably extends perpendicular to the flow direction of the medium.

[0032] A measuring electrode assembly consisting of at least two measuring electrodes has been pre-assembled for manufacturing a magnetic induction flow measurement probe, i.e., at least two measuring electrodes are interconnected via a connector. This measuring electrode assembly is then inserted into a tooling of an injection molding system and co-cast with a precursor. Alternatively, continuous holes can be formed in the precursor, into which measuring electrodes, typically designed as pointed electrodes, are pressed. Magnetic induction flow measurement probes with more than three measuring electrodes are known.

[0033] One embodiment specifies that the field guiding assembly includes a coil core, pole shoes, and / or a field return body.

[0034] The coil assembly can include exactly one coil or several coils. The coil typically includes a coil assembly carrier with an opening and at least one coil wire wound around the coil assembly carrier. The opening in the coil assembly carrier is preferably designed such that a field guide, for example in the form of a coil core and / or a field return body, can be inserted in a form-fitting manner. The magnetic induction flow measurement probe according to the invention preferably includes exactly one coil.

[0035] The pole shoe can be formed from separate components or it can be part of the coil core. In the second case, the portion of the coil core disposed between the coil or coil core and the coil and front of the magnetic induction flow measurement probe is understood as the pole shoe.

[0036] Traditional coil cores are designed to be completely cylindrical. According to the present invention, the coil core can be completely cylindrical or can be formed from at least one metal plate.

[0037] A field return element is used to return the magnetic field exiting the coil core and / or pole shoes in a controlled manner. For this purpose, it is attached to one end of the coil core. Hollow cylindrical field return elements are known. According to the invention, the field return element can be designed as a hollow cylinder or as a metal plate, particularly as part of at least one metal plate forming the coil core.

[0038] If the operating circuit is electrically connected to the field guide, a capacitance is formed between the field guide and the conductive medium during operation. This capacitance depends on the level of the medium in the pipeline. According to the invention, the level is determined based on the determined measured capacitance, specifically whether there is partial or complete filling.

[0039] If the operating circuit is electrically connected to the coil core, a capacitance is formed between the coil core and the conductive medium during operation. This capacitance depends on the level of the medium in the pipeline. According to the invention, the level is determined based on the determined measured capacitance, specifically whether there is partial or complete filling.

[0040] If the operating circuit is electrically connected to the electrode shoe, a capacitance is formed between the electrode shoe and the conductive medium during operation. This capacitance depends on the level of the medium in the pipeline. According to the invention, the level is determined based on the determined measured capacitance, specifically whether there is partial or complete filling.

[0041] If the various components of the field guiding assembly are in electrical contact, a capacitance is formed between the entire field guiding assembly and the conductive medium, which forms a measure of the level of the medium in the pipeline.

[0042] One embodiment specifies that the magnetic induction flow measurement probe includes annular electrodes arranged around the wall of the housing. The operating circuit is configured to apply an excitation signal to the field guide relative to the ring electrode.

[0043] The operating circuit is advantageously configured to determine a response signal with respect to the reference electrode at the field guide.

[0044] The electrodes can be formed from a hollow cylindrical metal shell, or they can be disposed as separate electrodes on the outer surface of the shell.

[0045] One embodiment specifies that the magnetic induction flow measurement probe is suitable for being fixed in a pipeline, particularly a metal pipeline, via a metal connector. The magnetic induction flow measurement probe is designed such that when the magnetic induction flow measurement probe is connected to the connector, an electrical contact is formed between the operating circuit and the connector. The operating circuit is configured to apply an excitation signal to the field guide relative to the connector.

[0046] One embodiment specifies that the field system has a field return body that is connected to the end of the coil core.

[0047] One embodiment specifies that at least one section of the field conductor contacts the electrically insulating wall of the housing.

[0048] One embodiment specifies that the wall of the housing has an outer surface capable of being impacted by a medium. The cutouts in the field guiding components are specifically spaced apart from the outer surface by the walls of the housing.

[0049] Ideally, the field conductor used as the sensor electrode is separated from the medium only by the wall of the housing. In this case, the capacitance formed between the field conductor and the medium depends primarily on the dielectric constant of the wall material, the wall thickness, and the medium-wetted contact surface between the medium and the housing. If the material level and the dimensions of the contact surface change, the material level or whether there is complete or partial filling can be determined based on the measurable capacitance.

[0050] One embodiment specifies that an operating circuit is connected to the coil device and configured to generate a clock-controlled magnetic field having an excitation phase and a rest phase, the rest phase being located between the two excitation phases, and wherein substantially no coil current flows. During one of the rest phases, an excitation signal is generated and a corresponding response signal is received.

[0051] To avoid zero-point offset, a clock-controlled magnetic field with alternating magnetic field directions is generated in most cases via a coil device. During the excitation phase, where the coil current at the coil device is substantially constant, the induced measurement voltage is determined and used to determine the induced measurement voltage related to the flow rate. According to an advantageous embodiment, rest phases are provided between the various excitation phases, where the coil current and thus the generated magnetic field are zero. During these rest phases, an excitation signal is applied to the sensor electrodes and a response signal is determined. This ensures that the induced measurement voltage has no effect on the response signal, and that the generated excitation signal has no effect on the measured induced voltage.

[0052] One embodiment specifies that the operating circuit is configured to determine, at least based on a response signal, a measured value of the capacitance of the field guiding component to the medium, and to determine information about the material level based on the deviation of the determined measured value from a reference value.

[0053] In the simplest case, determining the level information involves whether the pipeline is fully or partially filled. In the adjustment or calibration method, a reference capacitance is assigned to the magnetic induction flow measurement probe and represents the full or partial filling of the medium in the pipeline. If the determined measurement capacitance deviates from the reference capacitance, this deviation can be signaled to an operator or transmitted to an evaluation unit, which takes the level change into account when calculating the volumetric flow rate.

[0054] The method according to the present invention for determining the material level in a pipeline using a magnetic induction flow measurement device, particularly using a magnetic induction flow measurement device according to the present invention, comprises the following method steps: - Electrical, particularly time-alternating, excitation signals are supplied to the field conductor. - Receive electrical signals from the field guide. - At least based on the received signal, determine the measured capacitance of the field conductor, and - The material level in the pipeline or measuring tube is determined based on the measured capacitance. Attached Figure Description

[0055] The invention will be explained in more detail with reference to the following figures. As shown below: Figure 1 A partial three-dimensional cross-sectional view of a magnetic induction flow measurement probe based on existing technology; Figure 2 : A longitudinal section of an embodiment of the magnetic induction flow measurement probe according to the present invention inserted into a pipeline; Figure 3 Three views of an embodiment of the magnetic induction flow measurement probe according to the present invention; and Figure 4 The present invention provides a sequence of methods for determining the level of a medium in a measuring tube or pipeline using a magnetic induction flow measurement device. Detailed Implementation

[0056] Firstly, according to Figure 1 The perspective view and partial cross-sectional diagram illustrate the measurement principle upon which this invention is based. The flow measurement probe 1 includes a generally cylindrical housing 2 with a predetermined outer diameter. The housing is adapted to the diameter of an orifice located in pipeline 8 (…). Figure 1 Not shown in the image, but Figure 2 In the wall of the housing 2 (shown in the diagram), a flow measurement probe 1 is inserted into the pipeline 8 in a fluid-tight manner. The medium to be measured flows in the pipeline 8, and the flow measurement probe 1 is immersed in the medium almost perpendicular to the flow direction of the medium, as indicated by the wavy arrow 18. The front end 16 of the housing 2 protruding into the medium is sealed in a fluid-tight manner by a front body 15 made of insulating material. A magnetic field 9 extending into the medium through the end is generated by means of a coil device 6 arranged in the housing 2. A coil core 11, at least partially made of soft magnetic material and arranged in the housing 2, terminates at or near the end 16. A field return body 14 surrounding the coil device 6 and the coil core 11 is configured to return the magnetic field 9 extending through the end into the housing 2. The coil core 11, pole shoe 12, and field return body 14 are all field guides 10, which together form the field guiding assembly 5. First and second current measuring electrodes 3, 4 are arranged in the front body 15 and in contact with the medium. The voltage induced by Faraday's law of induction can be tapped at measuring electrodes 3 and 4 by means of a measuring and / or evaluating unit. This voltage is maximized if the flow measurement probe is installed in the pipeline such that the plane spanned by the straight line intersecting the two measuring electrodes 3 and 4 and the longitudinal axis of the flow measurement probe extends perpendicular to the flow direction 18 or perpendicular to the longitudinal axis of the pipeline. The operating circuit 7 is electrically connected to the coil assembly 6, specifically coil 13, and is configured to apply a clock-controlled excitation signal to the coil to thus generate a clock-controlled magnetic field 9.

[0057] Figure 2A longitudinal section of a magnetic induction flow measurement probe 1 installed in a pipeline 8 is shown. The flow measurement probe 1 is fixed in the pipeline 8 in a fluid-tight manner by means of a screw-in connector 22, which is inserted into and welded to the pipe wall 19 of the pipeline 8, for example. This structure of the measurement point is particularly advantageous because the screw-in connector 22 can be inserted into and welded into the pipeline 8 first, and only afterwards must the magnetic induction flow measurement probe 1, together with the connector 20, be inserted into the screw-in connector 22, screwed in, and sealed by means of a seal. As a result of the installation, an unknown installation angle is generated between the longitudinal axis of the pipe and the electrode axis. Two measuring electrodes 3, 4 are arranged symmetrically with respect to the center of end 16 on end 16. The coil core 11 is designed to be completely cylindrical and coaxially oriented with the housing. The field return body 14 is a hollow cylinder and contacts one end of the coil core 11. The coil core 11, the pole shoe 12, and the field return body 14 are integrally formed. Installation depth D indicates the depth to which the flow measurement probe 1 is inserted into the medium or projected into the pipeline.

[0058] According to the invention, the operating circuit 7 is connected to the field guiding assembly 5, particularly the field guide body 10 of the field guiding assembly 5. In the illustrated embodiment, the field guiding assembly 5 is integrally formed from the coil core 11, the pole shoe 12, and the field guide body 10. The operating circuit 7 is designed to generate, in particular, time-alternating excitation signals and supply them to the field guiding assembly 5 or the field guide body 10. Furthermore, the operating circuit 7 is configured to tap the response signal at the field guiding assembly 5 or the field guide body 10 and, at least based on the response signal, make a description of the level of the medium in the pipeline. The excitation signal and the response signal each have an amplitude and a frequency. The description of the level can be based on the amplitude difference. Alternatively, the operating circuit can be configured to determine a phase difference or a variable of two signals depending on the phase difference and make a description of the level based on it. Alternatively, the operating circuit can be configured to determine the level based on the frequency of the response signal. Alternatively, taking into account the excitation signal, the response signal, and the equivalent circuit diagram, the measuring capacitance can be determined, and a conclusion about the level can be drawn based on this.

[0059] Figure 3 A side view of an embodiment of the precursor 15 is shown, which has a coil assembly carrier 24 with a mounted coil core 11, a field return body 14, and a contact device 23. The precursor 15 shown has Figure 1 All the basic features are shown. In addition to the coil assembly carrier 24 and the precursor 15, the field return body 14, the coil core 11 extending through the cross-sectional area of ​​the coil 13, and the contact device 23 are also shown.

[0060] also, Figure 3A coil core 11 with field return bodies 14 is shown, together forming sensor electrodes. The coil core 11 is cylindrical, and the basic shape of the field return bodies 14 is a bent strip. Furthermore, the number of symmetrical field return bodies 14 is two. According to the depicted embodiment, the field return bodies 14 and the coil core 11 can be formed either monolithically. Alternatively, the field guiding assembly can consist of at least two assembled separate components. The field guiding assembly is arranged on the precursor and extends partially through an opening in the coil carrier. Two measuring electrodes are arranged in the precursor and connected to measuring and / or evaluation circuitry (not shown) via contact device 23. The contact device 23 is formed of a circuit board, particularly a flexible printed circuit board, on which measuring and / or operating circuitry can be arranged.

[0061] Figure 3 Two perspective views of the precursor 15 mounted on end 16 of housing 2 are also shown. Housing 2 has a basic cylindrical shape. Housing 2 can be cast using castable refractory for fixing field systems. The precursor 15 of the depicted embodiment has a measuring electrode arrangement, wherein two measuring electrodes 3, 4 are located on the diameter of the precursor 15. The precursor 15 is pressed into housing 2 in a medium-sealed manner, or arranged in a medium-sealed manner using a seal, particularly being compressed. The housing shell is designed to be conductive and serves as a reference electrode 17. In addition, the operating circuit 7 electrically connected to the field guiding assembly is co-cast into the housing. Alternatively, it can also be arranged outside housing 2.

[0062] Figure 4 A sequence of methods according to the invention for determining the level of a medium in a measuring tube using a magnetic induction flow measurement probe is shown. In a first method step A, time-alternating excitation signals are applied to a field guiding assembly. The field guiding assembly includes at least one field guide formed of at least one coil core and / or at least one pole shoe. The excitation signals are supplied via an operating circuit electrically connected to at least one of the field guiding assembly or field guide. In a further method step B, an electrical response signal is received from the field guiding assembly or field guide by means of the operating circuit. In this case, the supply and reception occur on a single field guide. Alternatively, the excitation signal can be applied to a first field guide and the response signal can be received at a second field guide. Based on the response signal, and taking into account the excitation signal, in a further method step C, a measuring capacitance, or a variable depending on the capacitance between the sensor electrode and the medium, is determined, which depends on the level of the medium in the measuring tube. In a final method step D, the level is determined based on the determined measuring capacitance or the variable depending on the capacitance between the sensor electrode and the medium. Alternatively, for example, the deviation of the determined measurement capacitance from a reference value or reference range can be determined, and a warning message can optionally be output or transmitted to an evaluation circuit configured to determine the volumetric flow rate based on the sensed measurement voltage.

[0063] List of reference numerals

[0064] 1. Magnetic induction flow measurement probe

[0065] 2. Shell

[0066] 3. Measuring electrodes

[0067] 4. Measuring electrodes

[0068] 5 field guidance components

[0069] 6. Coil assembly

[0070] 7. Operating Circuit

[0071] 8 pipelines

[0072] 9. Magnetic Field

[0073] 10 guiding events

[0074] 11. Coil core

[0075] 12 Extreme Boots

[0076] 13 coils

[0077] 14 return sessions

[0078] 15 precursors

[0079] 16 end

[0080] 17 Reference Electrode

[0081] 18. Flow direction of the medium

[0082] 19 Pipe wall

[0083] 20 Connectors

[0084] 21. Longitudinal axis of the tube

[0085] 22 Screw-in connectors

[0086] 23 Contact equipment

[0087] 24. Coil device carrier

Claims

1. A magnetic induction flow measurement device for determining the velocity-related measured variable of a flowable medium in a measuring pipe or pipeline, comprising: - Casing (2); - A device for tapping the measuring voltage induced in the flowable medium; - Devices used to generate magnetic fields The device for generating the magnetic field is arranged inside the housing (2). The device for generating the magnetic field includes a field guiding component (5) and a coil device (6). Among them, the coil core, pole shoe and field return body are all field guides and together form a field guide assembly (5). The field guiding component (5) is used as a sensor electrode for capacitively determining and / or monitoring at least one process variable.

2. The magnetic induction flow measurement device according to claim 1, in, The device for tapping the measuring voltage induced in the flowable medium is at least one measuring electrode (3, 4) for forming an electrical contact with the medium.

3. The magnetic induction flow measurement device according to claim 1, in, The at least one process variable is the level of the medium in the pipeline or the measuring tube.

4. The magnetic induction flow measurement device according to any one of claims 1 to 3, comprising: - Operating circuit (7), which is arranged in the housing (2), The operating circuit (7) is electrically connected to the field guiding component (5). The operating circuit (7) is configured to supply time-alternating excitation signals to the field guiding component (5), receive response signals from the field guiding component, and indicate the level of the medium in the pipeline or the measuring tube at least based on the response signals.

5. The magnetic induction flow measurement device according to claim 4, in, The magnetic induction flow measurement device includes a magnetic induction flow measurement probe, which is used to insert into a pipeline through which the medium can flow. The magnetic induction flow measurement probe includes a cylindrical housing configured to be supplied with the medium. The housing has an end, the end including at least partially electrically insulating walls. The at least two measuring electrodes are arranged in the wall of the housing. The device for generating the magnetic field is configured to generate a magnetic field that penetrates the end.

6. The magnetic induction flow measurement device according to claim 5, in, The magnetic induction flow measurement probe includes annular electrodes arranged around the wall of the housing. The operating circuit is configured to apply the excitation signal between the annular electrode and the field guide.

7. The magnetic induction flow measurement device according to claim 5 or 6, in, The magnetic induction flow measurement probe is suitable for being fixed in a pipeline via a metal connector. The magnetic induction flow measurement probe is designed such that when the magnetic induction flow measurement probe is connected to the connector, an electrical contact is formed between the operating circuit and the connector. The operating circuit is configured to apply the excitation signal between the connector and the field guide.

8. The magnetic induction flow measurement device according to claim 7, in, The magnetic induction flow measurement probe is suitable for being fixed in a metal pipeline via a metal connector.

9. The magnetic induction flow measurement device according to claim 5 or 6, in, The field system has a field return body that is connected to the end of the coil core.

10. The magnetic induction flow measurement device according to claim 5 or 6, in, At least one segment of the field guide is in contact with the electrically insulating wall of the housing.

11. The magnetic induction flow measurement device according to claim 5 or 6, in, The wall of the housing has an outer surface that can be impacted by the medium. The cutout of the field guiding component is specifically spaced apart from the outer surface by the wall of the housing.

12. The magnetic induction flow measurement device according to claim 5 or 6, in, The operating circuit is connected to the coil assembly and configured to generate a clock-controlled magnetic field with an excitation phase and a rest phase, the rest phase being located between the two excitation phases and in which no coil current flows. In one of the rest phases, the excitation signal is generated and the corresponding response signal is received.

13. The magnetic induction flow measurement device according to claim 5 or 6, in, The operating circuit is configured to determine, at least based on the response signal, a measured value of the capacitance of the field guiding component to the medium, and to determine information about the material level based on the deviation of the determined measured value from a reference capacitance.

14. A method for determining the material level in a pipeline using a magnetic induction flow measurement device according to any one of claims 1 to 13, comprising the following method steps: - An excitation signal that supplies electricity to the field guide body. - Receive electrical reception signals from the field guide. - Determine the measured capacitance of the field conductor based at least on the received signal, and - Determine the material level in the pipeline or measuring tube based on the measured capacitance.

15. The method according to claim 14, in, The excitation signal is applied to the field guide body in an alternating manner.

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