Measuring system

Abstract

The invention relates to a measuring system for measuring at least one flow parameter of a fluid measuring material flowing in a pipeline, said measuring system comprising:-a conduit (3); -a bluff body (4) arranged in the conduit (3) and designed to generate vortices in the measurement material flowing through the bluff body; -an eddy current sensor (1), which is arranged downstream of the bluff body, which eddy current sensor is designed to generate mechanical vibrations when excited by the flowing measuring material and to provide at least one eddy current sensor signal (s1) and has a magnetostrictive material (11); -a magnetic field detection unit (10) designed to measure a change in the magnetic field resulting from a mechanical force acting on the magnetostrictive material (11) and to provide a magnetic field detection signal (m1); and converter electronics (2) for analyzing the at least one eddy current sensor signal and for analyzing a functional and / or rationality statement with respect to the eddy current sensor signal provided by the eddy current sensor (1) on the basis of the magnetic field detection signal (m1).

Description

Technical Field

[0001] The invention relates to a measuring system, in particular a vortex flowmeter, for measuring at least one flow parameter, in particular a time-varying flow parameter, in particular a flow velocity and / or a volume flow rate and / or a mass flow rate, of a fluid measuring substance, in particular a gas, a liquid or a dispersion, flowing in a pipeline. Background Art

[0002] In process measurement and automation technology, measuring systems designed as vortex flow meters are often used to measure the flow velocity of fluids flowing in pipelines, especially fast flows and / or hot gases and / or fluid flows with high Reynolds numbers (Re), or corresponding flow velocities ( )’s volume flow rate or mass flow rate. Examples of such measuring systems are known in particular from US 2006 / 0230841, US 2008 / 0072686, US 2011 / 0154913, US 2011 / 0247430, US 2016 / 0123783, US 2017 / 0284841, US 2019 / 0094054, US 60 03 384, US 61 01 885, US 63 52 000, US 69 10 387, or US 69 38 496 and are offered in particular by the applicant under the trade names “PROWIRL D 200”, “PROWIRL F 200”, “PROWIRL O 200”, “PROWIRL R 200” (http: / / www.de.endress.com / #products / prowirl).

[0003] Each of the measuring systems shown has a resistance element which projects into the cavity of the corresponding pipeline, for example a system component designed as a thermal supply network or a turbine circuit, or into the cavity of a measuring tube used in the line of said pipeline, against which the fluid flows to generate vortices which are arranged in a row to form a so-called Karman vortex street in the partial volume of the fluid flow flowing directly downstream of the resistance element. As is known, the vortices are formed at the resistance element at a shedding rate ( ) is generated. Furthermore, the measuring system has a sensor which is integrated in the resistance element or connected thereto or connected downstream thereof, i.e. in the region of the Karman vortex street in the flow, thus entering into the cavity of the protruding sensor, which serves to detect the pressure fluctuations in the Karman vortex street formed in the flowing fluid and converts them into a sensor signal representing the pressure fluctuations, i.e. supplies a signal - here for example an electrical signal or an optical signal - corresponding to the pressure prevailing in the fluid, which is subjected to periodic fluctuations downstream of the resistance element due to the opposing vortices, or has a signal frequency corresponding to the shedding rate of the vortices ( ).

[0004] For this purpose, the sensor has a deformation element and a sensor lug extending from a substantially flat surface of the deformation element, which is usually rod-shaped, flat or wedge-shaped and is designed to detect pressure fluctuations in the Karman vortex street, i.e. convert them into a movement of the deformation element corresponding to the pressure fluctuations. The deformation element has an outer edge segment, which is usually annular, which is configured to be hermetically sealed (e.g. integrally joined) to a socket for holding the deformation element on the wall of the pipeline, so that the deformation element covers and hermetically seals an opening provided in the wall of the pipeline, and the surface of the deformation element supporting the sensor lug faces the fluid-carrying cavity of the measuring tube or pipeline, and the sensor lug thus protrudes into the cavity. The deformation element is usually designed as a thin film and is shaped so that at least one membrane thickness measured by the minimum thickness of the inner membrane segment defined by the above-mentioned outer edge segment is much smaller than the membrane diameter measured by the maximum diameter of the surface defined by the outer edge segment. In order to achieve the highest possible measurement sensitivity with the sensor lug, i.e. the highest possible sensitivity of the sensor to the pressure fluctuations to be detected, and at the same time, to achieve the highest possible mechanical natural frequency for the bending vibration modes of the deformation element caused by the pressure fluctuations (which frequency is above the highest shedding rate to be measured), such deformation elements of established measuring systems usually have a ratio of diameter to thickness of the order of about 20: 1. As shown above, in particular in US-A 2016 / 0123783, US-A 2017 / 0284841, US-A 2019 / 0094054, or US-B 63 52 000, etc., sensors of the type in question can sometimes also have a compensation element, usually in the form of a rod, plane or sleeve, which extends from a surface of the deformation element remote from the surface supporting the sensor lug and is used in particular to compensate for forces or moments resulting from movements of the sensor assembly, for example as a result of vibrations of the pipeline, or to avoid undesired movements of the sensor lug resulting therefrom.

[0005] For the purpose of generating a sensor signal, each of the sensors also comprises a (mechanical to electrical) transducer element, which is generally configured to detect a movement of the deformation element and convert it into an electrical sensor signal. In the sensors known from US-A 2017 / 0284841, US-A 2019 / 0094054 or US-B 63 52 000, the transducer element is formed by means of a piezoelectric ceramic, for example in the form of a piezoelectric disk.

[0006] On the side facing away from the fluid-carrying cavity, the sensor is also connected to a transducer electronics system, which is usually packaged in a pressure-resistant and impact-resistant manner and optionally also hermetically sealed to the outside. The transducer electronics system of a measuring system suitable for industrial applications usually has a corresponding digital measuring circuit, which is electrically connected to the transducer element via a connecting line, optionally with the insertion of an electrical barrier and / or a galvanic isolation point, for processing at least one sensor signal generated by the transducer element and generating a digital measurement value for the measured variable to be detected in each case, i.e., the flow velocity, volume flow rate and / or mass flow rate. The transducer electronics system suitable for a measuring system for industry or established in industrial measurement technology, which is usually accommodated in a protective housing made of metal and / or impact-resistant plastic, usually also provides an external interface in accordance with industrial standards such as DIN IEC60381-1 for communication with a higher-level measuring and / or regulating system, for example formed by means of a programmable logic controller (PLC). Such an external interface can be designed, for example, as a two-wire connection, which can be incorporated into a current loop and / or is compatible with established industrial fieldbuses.

[0007] Not only due to the relatively high diameter-to-thickness ratio of the deformation element which is the cause of the measuring principle, conventional sensors of the type in question - even when using high-strength nickel-based alloys such as, for example, Inconel 718 (Special Metals Corp.) as material - typically have a compressive strength, i.e. a maximum permissible operating pressure, above which irreversible plastic deformation of the sensor or even rupture of the deformation element will occur, which may be too low for the extremely high pressures or pressure shocks which occasionally occur in practice in certain applications, or such sensors exhibit a dependence of the compressive strength on the operating temperature (pressure-temperature curve) which is too unfavorable for such applications, so that, for example, loss-free resistance may no longer be guaranteed for operating pressures above 100 bar (which occasionally occur in practice in predefined hot steam applications with steam temperatures above 200° C., for example as a result of condensation water hammer (CIWH)).

[0008] A more recent development in the field of sensor technology is represented by so-called quantum sensors, in which various quantum effects are utilized to determine various physical and / or chemical measured variables. In the field of industrial process automation, this approach is of interest, in particular with regard to the increasing efforts towards miniaturization while at the same time improving the performance of the corresponding sensors.

[0009] Quantum sensors are based on the fact that certain quantum states of individual atoms can be controlled and read very precisely. In this way, for example, electric and / or magnetic fields as well as gravitational fields can be measured precisely and with low interference with a spatial resolution in the nanometer range. In this context, various spin-based sensor assemblies are known, in which atomic transitions in a crystalline body are used to detect movements, changes in the electric and / or magnetic or gravitational fields. Furthermore, different systems based on quantum optical effects are also known, such as quantum gravimeters, NMR gyroscopes or optically pumped magnetometers, wherein the latter in particular are based on gas cells.

[0010] For example, in the field of spin-based quantum sensors, various devices are known that utilize atomic transitions in various crystal hosts, for example, in order to detect small changes in motion, electric and / or magnetic fields or even gravitational fields. Typically, diamond with at least one nitrogen vacancy center, silicon carbide with at least one silicon vacancy or hexagonal boron nitride with at least one vacancy color center is used as a crystal host. The crystal host can in principle have one or more vacancies.

[0011] DE 10 2017 205 099 A1 discloses a sensor device having a crystal body with at least one vacancy, a light source, a high-frequency device for applying a high-frequency signal to the crystal body, and a detection device for detecting a magnetic field-dependent fluorescence signal. The light source is arranged on a first substrate and the detection device is arranged on a second substrate, while the high-frequency device and the crystal body can be arranged on two mutually connected substrates. An external magnetic field, an electric current, a temperature, a mechanical stress or a pressure can be used as a measured variable. A similar device is already known from DE 10 2017 205 265 A1.

[0012] DE 10 2014 219 550 A1 describes a combined sensor for detecting pressure, temperature and / or magnetic fields, wherein the sensor element has a diamond structure with at least one nitrogen-vacancy center.

[0013] DE 10 2018 214 617 A1 discloses a sensor device which also has a crystal body with a plurality of color centers, in which various optical filter elements are used to increase the efficiency and for miniaturization.

[0014] From the German patent application with the document number 10 2020 123993.9, which has not yet been published, a sensor device is known which uses the fluorescence signal of a crystalline body with at least one vacancy in order to evaluate a process variable of the measured substance. In addition, state monitoring of the corresponding process is performed based on a variable related to the magnetic field, such as the magnetic permeability or the magnetic susceptibility. From the German patent application with the document number 10 2021 100223.0, which has not yet been published, a point level sensor is also known, in which statements about the point level are determined based on the fluorescence.

[0015] Many applications in process measurement and automation require extremely reliable measurement systems that ensure the specified measurement accuracy is maintained. Summary of the invention

[0016] The invention is based on the object of proposing a measuring system for measuring at least one flow parameter, which system is able to reliably provide measured values ​​with a predetermined measurement accuracy.

[0017] This object is achieved by a measuring system according to claim 1 .

[0018] The measuring system according to the invention is a measuring system for measuring at least one flow parameter, in particular a flow parameter varying over time, in particular a flow velocity and / or a volume flow rate and / or a mass flow rate, of a fluid measuring substance, in particular a gas, a liquid or a dispersion, flowing in a pipeline, comprising:

[0019] a pipe which can be inserted into the line of the pipeline and has a cavity configured to guide a measurement substance flowing in the pipeline or to allow the measurement substance to flow through the cavity;

[0020] - a bluff body, in particular a prismatic or cylindrical bluff body, arranged in the cavity of the pipe and configured to be shaped at a shedding frequency The generation of eddies in the flowing measured substance, the shedding frequency of which depends on the current flow velocity of the measured substance , so that a Karman vortex street is formed in the fluid flowing downstream of the bluff body;

[0021] - an eddy current sensor arranged downstream of the bluff body,

[0022] --Has at least one mechanical resonant frequency , especially the lowest and / or consistently higher than the shedding frequency ,and

[0023] - configured to generate mechanical oscillations in the vicinity of a static rest position when excited by a flowing measurement substance and to provide at least one - in particular electrical or optical - eddy current sensor signal representative of said oscillations, and

[0024] --With magnetostrictive materials;

[0025] - a magnetic field detection unit designed to measure the changes in the magnetic field due to the effect of a mechanical force acting on a magnetostrictive material and designed to provide a magnetic field detection signal representative of the same effect, in particular an electromagnetic field detection signal or an optical magnetic field detection signal;

[0026] - and converter electronics, which are formed in particular by means of at least one microprocessor and are used for analyzing at least one eddy current sensor signal, for ascertaining a measured value, in particular a digital measured value, of at least one flow parameter, and for analyzing functionality and / or plausibility statements about the eddy current sensor signal supplied by the eddy current sensor based on the magnetic field detection signal.

[0027] By monitoring the functionality of the measuring system, it can be ensured that the eddy current sensor reliably supplies measured values ​​within a guaranteed measurement accuracy throughout its entire service life. If the deviation of the measured values ​​exceeds a predetermined limit, this indicates that the measuring system needs to be repaired or replaced. This monitoring can be performed continuously or during scheduled maintenance intervals. Furthermore, as an alternative or in addition, the measuring system supplies redundant measured values ​​continuously or at predetermined time intervals, which at least allows a plausibility statement to be made for the supplied measured values. This makes it possible to use the measuring system according to the invention also in safety-critical applications.

[0028] Magnetostriction is the change in the geometrical dimensions of a ferromagnetic body under the influence of a magnetic field. This effect is measurable in all ferromagnetic materials. In connection with the present invention, the opposite effect, the so-called Villari effect, comes into play, i.e. the change in the magnetic field or the magnetic properties of a magnetostrictive material under the influence of a mechanical force acting on the material is taken into account. Among the elements or metals in pure static form, iron, nickel and cobalt exhibit ferromagnetism at room temperature. A fourth element that has ferromagnetism at room temperature has been identified as ruthenium in a metastable body-centered tetragonal phase. Ferromagnetic alloys such as AlNiCo, SmCo, Nd2Fe14B, Ni80Fe20 ("Permalloy") or NiFeCo alloys ("Mumetal") are suitable for practical applications. Which ferromagnetic material is used in connection with the present invention depends on whether the ferromagnetic material is in contact with the measured substance or is arranged in isolation from the measured substance.

[0029] Magnetostrictive materials do not generate their own magnetic field, but change their magnetic permeability under the influence of the applied force µ. In order to measure the change in the magnetic field, it is therefore necessary to generate an offset magnetic field, for example by using a permanent magnet or a coil. The change in the magnetic field caused by the force acting on the magnetostrictive material can be measured using a magnetic field detection unit.

[0030] Advantageous embodiments of the invention are subject matter of the dependent claims.

[0031] One embodiment provides that the eddy current sensor has a deformation element, in particular a membrane-shaped and / or disk-shaped deformation element, which has a first surface facing the cavity and an opposite second surface, the second surface in particular being at least partially parallel to the first surface, and

[0032] Therein, the eddy current sensor has at least one transducer element, which is arranged above and / or on the second surface of the deformation element, in particular, attached to the deformation element and / or located near the deformation element, and is configured to detect the movement of the deformation element, in particular the movement of its second surface and convert it into an eddy current sensor signal.

[0033] One embodiment provides that the eddy current sensor has a sensor lug, in particular a planar or wedge-shaped sensor lug, which extends from the first surface of the deformation element to a distal end.

[0034] One embodiment provides that the deforming element is made of a magnetostrictive material, is coated with a magnetostrictive material, or is at least partially covered by a body comprising a magnetostrictive material.

[0035] One embodiment provides that the sensor lug is made of a magnetostrictive material, is coated with a magnetostrictive material, or is at least partially covered by a body comprising a magnetostrictive material.

[0036] One embodiment provides that the deformation element or the sensor lug is provided with a coating made of magnetostrictive material, is made of said magnetostrictive material or is covered by a body comprising magnetostrictive material, at least in a partial region in which the maximum mechanical stresses or the maximum deflections occur during oscillations about a static rest position.

[0037] In principle, known magnetic field detection units can be used in conjunction with the present invention. Preferably, however, the magnetic field detection unit is a quantum sensor. Quantum sensors are already known in various designs. They use different quantum effects to determine various physical and / or chemical process variables. In the field of industrial process automation, the use of quantum sensors is interesting in two aspects: quantum sensors make it possible to minimize the sensors used while improving their performance.

[0038] An embodiment provides that the magnetic field detection unit is a quantum sensor.

[0039] One embodiment provides a quantum sensor having at least one crystal body having at least one magnetic field-sensitive vacancy.

[0040] Preferably, two types of quantum sensors are used in combination with the measuring system. The magnetic field detection unit can be a quantum sensor having at least one crystal body with at least one magnetic field-sensitive vacancy. The crystal body can be, for example, diamond with at least one nitrogen vacancy, silicon carbide with at least one silicon vacancy, or hexagonal boron nitride with at least one vacancy color center. Of course, there can also be a plurality of vacancies in the crystal body. These vacancies are preferably arranged linearly. An increase in the number of vacancies leads to an increase in intensity, thereby improving the measurement resolution, and intensity changes can be detected even in relatively weak magnetic fields.

[0041] A large number of quantum sensors that can be used for process automation are already known from the patent literature. For example, DE 37 42 878 A1 describes an optical magnetic sensor in which a crystal is used as a magnetosensitive optical component.

[0042] DE 102017205099A1 discloses a sensor device having a crystal body with at least one vacancy, a light source, a high-frequency device for applying a high-frequency signal to the crystal body, and a detection unit for detecting a fluorescent signal dependent on a magnetic field. The light source is arranged on a first substrate, and the detection device is arranged on a second substrate, while the high-frequency device and the crystal body can be arranged on two interconnected substrates. An external magnetic field, an electric current, a temperature, a mechanical stress or a pressure can be used as a measured variable. A similar device is already known from DE 102017205265A1.

[0043] DE 10 2014 219 550 A1 describes a combined sensor for detecting pressure, temperature and / or magnetic fields, wherein the sensor element has a diamond structure with at least one nitrogen-vacancy center.

[0044] DE 10 2018 214 617 A1 discloses a sensor device which also has a crystal body with a plurality of color centers, in which various optical filter elements are used to increase the efficiency and for miniaturization.

[0045] DE 102016210259A1 proposes another embodiment of a sensor device and a calibration and evaluation method based on vacancies in a crystal. The sensor device comprises a crystal body having at least one vacancy, a light source, a microwave antenna for applying microwaves to the crystal body, a detection device for detecting fluorescence from the crystal body, and an application device by means of which an induced current can be applied to the microwave antenna. The microwave antenna is used to generate both microwaves and an internal magnetic field. The internal magnetic field makes it possible to perform calibration during continuous operation.

[0046] One embodiment provides that the magnetic field detection unit has an excitation device, in particular an optical excitation device, for exciting vacancies or for exciting gas cells, and a detection device, in particular an optical detection device, for detecting magnetic field-related signals of the crystal body or the gas cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention is explained in more detail with reference to the following drawings. In the drawings:

[0048] Figure 1 : is a perspective view of a measurement system, specifically a vortex flowmeter;

[0049] Figure 2a : is a perspective view of a first embodiment of an eddy current sensor;

[0050] Figure 2b : is a perspective view of a second embodiment of an eddy current sensor;

[0051] Figure 3 : is a longitudinal section through an embodiment of the measurement system; and

[0052] Figure 4 : is a schematic representation of an embodiment of a magnetic field detection unit. DETAILED DESCRIPTION

[0053] Figure 1 is a perspective view of a measuring system for measuring at least one flow parameter (optionally also variable over time) of a fluid flowing in a pipeline, such as a flow velocity v and / or a volume flow rate , for example, in particular hot gases which at least temporarily have a temperature of more than 200° C. and / or which are at least temporarily under high pressure (in particular more than 100 bar), the measuring system being in particular a vortex flow meter. The pipeline can be designed, for example, as a component of an installation of a heat supply network or a turbine circuit, and the fluid can therefore be, for example, steam, in particular saturated steam or superheated steam, or, for example, condensate discharged from a steam line. However, the fluid can also be, for example, (compressed) natural gas or biogas, so that the pipeline can also be, for example, a component of a natural gas or biogas installation or a gas supply network.

[0054] The measuring system comprises an eddy current sensor 1, Figure 3 It is shown again in enlargement in FIG. 1 , which is arranged or configured to detect pressure fluctuations in a fluid flowing through the sensor in a (main) flow direction and to convert them into a sensor signal s1 corresponding to said pressure fluctuations—for example, an electrical or optical sensor signal s1 . Figure 1 and Figure 3As is apparent when viewed together, the measuring system further comprises a converter electronics 2 - for example housed in a pressure- and / or impact-resistant protective housing 20 - electrically connected to the eddy current sensor 1 or communicating with the eddy current sensor 1 during operation of the measuring system. The converter electronics 2 is in particular configured to receive and process the sensor signal s1, i.e., for example, to generate a signal representative of at least one flow parameter (i.e., for example, the flow velocity v or the volume flow rate The measured value XM can be visualized, for example, on site and / or transmitted in a wired manner via a connected field bus and / or wirelessly via radio to an electronic data processing system, such as a programmable logic controller (PLC) and / or a process control station.

[0055] The protective housing 20 of the converter electronics 2 can be produced, for example, from metal such as stainless steel or aluminum and / or by means of casting such as investment casting or pressure die casting (HPDC); however, it can also be formed, for example, as a plastic molded part produced by means of an injection molding method.

[0056] like Figure 3 Shown or from Figure 2a / Figure 2b and Figure 3As is readily apparent when viewed together, the eddy current sensor 1 comprises a deformation element 111, in particular a membrane-shaped or disk-shaped deformation element, and a sensor lug 22 having a first side surface on the left and a second side surface on the right, which extends from a first surface 111+ of the deformation element 111 to a distal end (free end) that is remote from the deformation element 111 or its surface 111+. The deformation element 111 also has a second surface 111# that is opposite to the first surface 111+—for example, at least partially parallel to the first surface 111+. The deformation element 111 and the sensor lug 22 can, for example, be components of one and the same integral molded part, which is cast or produced by an additive manufacturing process such as 3D laser melting; however, the deformation element and the sensor lug can also be designed as separate parts, which are initially separated from each other and only subsequently integrally joined to each other, for example welded or brazed to each other, and are therefore produced from materials that can be correspondingly integrally joined to each other. The deformation element 111 can at least partially, that is, for example, mainly or completely, consist of a metal such as stainless steel or a nickel-based alloy. The sensor lug 22 can likewise consist at least partially of a metal, i.e., for example, stainless steel or a nickel-based alloy; the deformation element 111 and the sensor lug 22 can in particular also be produced from the same material. Furthermore, the deformation element 111 and the sensor lug 22 are in particular configured to be excited to oscillate - usually forced - about a common static rest position, so that the sensor lug 22 performs a swinging movement, which causes the deformation element 111 to deform elastically in a detection direction substantially transverse to the above-mentioned flow direction. Correspondingly, the width of the sensor lug 22 measured along the maximum extension in the flow direction is significantly greater than the thickness of the sensor lug 22 measured along the maximum lateral extension in the detection direction. Furthermore, the sensor lug 22 can be designed, for example, as a wedge, or also as a relatively thin flat plate, which is quite common in sensors of this type.

[0057] In addition to the sensor lug 22 and the deformation element 111, the eddy current sensor 1 also has a connecting sleeve 113 extending from a circular circumferential edge section of the second surface 111# of the deformation element, which edge section extends in a circle, for example. In order to detect the oscillations of the deformation element 111 and the sensor lug, the eddy current sensor 1 also has at least one transducer element 112, in particular a disk-shaped and / or piezoelectric ceramic transducer element, which is arranged in the connecting sleeve 113 and contacts the surface 111+ of the deformation element with a first contact surface, for generating an electrical sensor signal representing a time-varying, in particular at least temporarily periodic movement of the sensor lug and / or a likewise time-varying, in particular at least temporarily periodic deformation of the deformation element 111, for example with an (alternating) voltage corresponding to the above-mentioned movement.

[0058] According to another embodiment of the present invention, the measuring system further comprises a pipe 3, which can be inserted into the route of the above-mentioned pipeline and has a cavity 3', which is surrounded by a wall 3* (e.g. a metal wall) of the pipeline and extends from an inlet end 3+ to an outlet end 3#, and is configured to guide the fluid flowing in the pipeline. Furthermore, the eddy current sensor 1 is inserted into the pipeline so that the first surface of the deformation element 111 faces the cavity 3' of the pipeline, so that the sensor lug protrudes into the cavity. In the exemplary embodiment shown here, there are flanges at both the inlet end 3+ and the outlet end 3#, which are used in each case to establish a leak-free flange connection with a corresponding flange on the inlet-side or outlet-side line segment of the pipeline. Furthermore, as Figure 1 or Figure 3 As shown, the duct 3 may be substantially straight, for example in the form of a hollow cylinder with a circular cross section, so that the duct 3 has an imaginary straight longitudinal axis L connecting the inlet end 3+ and the outlet end 3#. Figure 1 or Figure 3 In the exemplary embodiment shown, the eddy current sensor 1 is inserted from the outside into the cavity of the pipe through an opening 3 ″ formed in the wall and is fastened from the outside - for example releasably - to the wall 3 * in the region of said opening, so that the surface 111 + of the deformation element 111 faces the cavity 3 ′ of the pipe 3 and the sensor lug 22 thus protrudes into said cavity. In particular, the eddy current sensor 1 is inserted into the opening 3 ″ so that the deformation element 111 covers or hermetically seals the opening 3 ″. The opening can be designed, for example, so that it has an (inner) diameter in the range between 10 mm and about 50 mm which is quite common in measuring systems of the type in question. According to another embodiment of the invention, a socket 3 a is formed in the opening 3 ″, which socket 3 a is used to accommodate the deformation element 111 or the sensor 1 formed therewith on the wall 3 *. In this case, the eddy current sensor 1 can be fastened to the pipe 3, for example, by integrally joining the deformation element 111 and the wall 3 *, in particular by welding or soldering; however, it can also be, for example, detachably connected to the pipe 3, for example screwed to or onto the pipe 3. In addition, at least one sealing surface, for example a circumferential or annular sealing surface, can be formed in the socket 3a, and the sealing surface is configured to cooperate with the deformation element 111 and an optionally provided sealing element, for example an annular or annular disk, to correspondingly seal the opening 3''.

[0059] exist Figure 1 or Figure 3In the exemplary embodiment shown, the measuring system is designed specifically as a vortex flow meter, which has a resistance element 4, which is arranged in the cavity of the pipeline 3 - here, upstream of the sensor 1, i.e. in the (main) direction upstream of the sensor - and serves to form a Karman vortex street in the flowing fluid. Here, the sensor and the resistance element are specifically dimensioned and arranged so that the sensor lug 22 protrudes into the cavity 3* of the pipeline, or into the fluid conducted therein, and during operation of the measuring system, this area is regularly occupied by a (fixedly formed) Karman vortex street, so that the pressure fluctuations detected by means of the sensor 1 are caused by the shedding rate ( ) at the resistance element 4. ) causes periodic pressure fluctuations caused by the vortex shedding, and the sensor signal s1 has a signal frequency corresponding to the shedding rate of the vortex ( In the exemplary embodiment shown here, the vortex flow meter is also designed as a compact measuring system, in which the measuring electronics 2 is accommodated in a protective housing 20 which is held on the pipeline—for example, by means of a neck-shaped connection 30 .

[0060] According to another embodiment of the present invention, in order to compensate for forces and / or moments caused by random movements of the sensor (e.g., as a result of vibrations of the pipeline connected to the pipeline as mentioned above), or to prevent the resulting unwanted movement of the sensor lug or the deformation element 111 (i.e., distorting the sensor signal s1), the eddy current sensor 1 also has a compensation element 114, for example, a rod-shaped, plane-shaped or sleeve-shaped compensation element extending from the second surface 111# of the deformation element 111. The compensation element 114 can, for example, be composed of the same material as the deformation element and / or the sensor lug (e.g., metal). For example, the compensation element 114 can be produced from stainless steel or a nickel-based alloy. According to another embodiment of the present invention, the deformation element 111 and the compensation element 114 are integrally joined to each other, for example, welded or brazed to each other, and thus the compensation element 114 and the deformation element 111 are produced from materials that can be integrally joined to each other. Alternatively, however, the deformation element 111 and the compensation element 114 can also be parts of one and the same integral molded part, for example, so that the sensor lug 111, the deformation element 112 and the compensation element 114 can also be parts of said molded part. The sensor lug 22 and the compensation element 114 can also be arranged aligned with each other, so that the main axis of inertia of the sensor lug 22 coincides in extension with the main axis of inertia of the compensation element 114. Alternatively or additionally, the compensation element 114 and the deformation element 111 can also be positioned and aligned with each other, so that the main axis of inertia of the deformation element 111 coincides in extension with the main axis of inertia of the compensation element 114.

[0061] Figure 1 Combination Figure 3The eddy current sensor 1 is shown to comprise a magnetostrictive material 11 and a magnetic field detection unit 10 designed to measure the change of a magnetic field due to a mechanical force acting on the magnetostrictive material 11 and to provide a magnetic field detection signal m1, in particular an electrical or optical magnetic field detection signal, representative of the same. The converter electronics 2 is suitable and configured to determine a measured value, in particular a digital measured value, of at least one flow parameter using at least one eddy current sensor signal. , and analyzes functionality and / or plausibility statements about the eddy current sensor signal s1 supplied by the eddy current sensor 1 based on the magnetic field detection signal m1.

[0062] According to the invention, a suitable magnetic field detection unit 10 is provided, which measures the magnetic field that occurs in the magnetostrictive material due to mechanical forces acting on the vibration unit 4 (Villari effect). A control / evaluation unit as part of the converter electronics 2 of the measuring system generates statements about the functionality of the eddy current sensor 1 based on the measured magnetic field and / or makes plausibility statements for the eddy current sensor signal s1 supplied by the eddy current sensor.

[0063] Preferably, the magnetic field detection unit 10 is a quantum sensor. Different embodiments of quantum sensors have been described in detail above, so there is no need to repeat them here. Compared with conventional magnetic field detection sensors (such as Hall sensors), quantum sensors have the advantages of small size - that is, they can also be preferably integrated into the vibrating electronic sensor 1 - and extremely high measurement sensitivity. Of course, the magnetic field detection unit 10 can also be designed as a separate component and placed outside the eddy current sensor 1 so that the magnetic field is measured. The magnetostrictive material 11 generates a magnetic field with the help of a magnet (for example, a permanent magnet that generates a bias magnetic field), and the magnetic field can be measured by the magnetic field detection unit 10 with the required accuracy. The magnetostrictive material 11 itself does not generate its own magnetic field, but changes its magnetic permeability under the influence of the force µ acting on it. For this reason, a bias magnetic field needs to be generated, for example, with the help of a permanent magnet or a coil, in order to measure the change in the magnetic field caused by the force acting on the magnetostrictive material 11. Although quantum sensors are preferably used for analyzing the magnetic field in conjunction with the present invention, it goes without saying that, depending on the embodiment and arrangement of the magnetostrictive material 11 and the permanent magnet on the eddy current sensor 1, conventional magnetic field sensors can also be used.

[0064] Figure 2a is a perspective view of a first embodiment of an eddy current sensor 1. The sensor lug 22 is at least partially coated with a magnetostrictive material 11 or is at least partially covered by a body comprising the magnetostrictive material 11.

[0065] Figure 2bis a perspective view of a second embodiment of an eddy current sensor 1. The deformation element 111 is at least partially coated with a magnetostrictive material 11. The deformation element 111 or the sensor lug 22 comprises a magnetostrictive material 11 at least in a partial region in which maximum mechanical stresses or maximum deflections occur during oscillations about a static rest position.

[0066] Alternatively, the sensor lug 22 and / or the deformation element 111 may be made of a magnetostrictive material 11 .

[0067] Figure 4 The quantum sensor schematically shown in comprises at least one magnetic field-sensitive nitrogen-vacancy center (NV center) in diamond. The following considerations can be transferred to other crystal bodies 30 having corresponding vacancies.

[0068] In diamond, each carbon atom is typically covalently bonded to four other carbon atoms. A nitrogen-vacancy center (NV center) consists of a vacancy (i.e., an unoccupied lattice site) in the diamond lattice and a nitrogen atom that is one of the four neighboring atoms. In particular, the negatively charged The center is very important for the excitation and evaluation of the fluorescence signal. In the energy diagram of the negatively charged NV center, there is a triplet ground state 3 A and triplet excited state 3 E, each of which has three magnetic substates In addition, in the ground state 3 A and excited state 3 There are two metastable singlet states between E 1 A and 1 E. In the absence of an external magnetic field, the two states From the ground state splitting, which is called zero field splitting and depends on the temperature T.

[0069] Excitation light from the green range of the visible spectrum (e.g., excitation light with a wavelength of 532 nm) excites electrons from the ground state 3A to the vibrational state of the excited state 3E, which returns to the ground state 3A by emitting a fluorescence photon with a wavelength of 630 nm. This fluorescence signal is zero-field splitting and can be used to determine and / or monitor the temperature T.

[0070] An applied magnetic field with a magnetic flux density leads to a splitting of the magnetic substates (Zeeman splitting), so that the ground state consists of three energetically separated substates, each of which can be excited. However, the intensity of the fluorescence signal depends on the corresponding magnetic substate that excites it, so that, for example, the magnetic flux density B can be calculated using the Zeeman formula based on the distance between the fluorescence minima. This principle is used in a magnetic field detection unit with a microwave generating device. In this case, the magnetic flux density or the smallest change in the magnetic flux density can be determined. However, quantum sensors are also known, which utilize the properties of the ground state level anticrossing (GSLAC) and can therefore operate without microwaves. For more details, see the publications "Microwave-free magnetometry with nitrogen-vacancy centers in diamond" by Wickenbrock et al. and "NV–NV electron–electronspin and NV–NS electron — electron and electron-nuclear spin interaction indiamond" by Armstrong et al.

[0071] In the context of the present invention, further possibilities for evaluating the fluorescence signal are provided, such as evaluating the intensity of the fluorescence, which is likewise proportional to the applied magnetic field. In turn, an electrical evaluation can be performed, for example, via magnetic resonance photocurrent detection (PDMR). Alternatively, as already described, various excitation query sequences can be used for targeted control and manipulation of nuclear spins. In addition to these examples for evaluating the fluorescence signal, there are other possibilities that also fall within the scope of the present invention.

[0072] Figure 4A schematic longitudinal section through an embodiment of a magnetic field detection unit 10, in particular a quantum sensor, is shown, wherein the magnetic field detection unit 10 has an excitation device 40, in particular an optical excitation device, for exciting vacancies or for exciting gas cells, and a detection device 50, in particular an optical detection device, for detecting magnetic field-related signals of a crystal body 30 or a gas cell. The optical excitation device 40 is designed to excite the crystal body by generating an optical excitation signal, in particular light with a fixed frequency, so as to polarize vacancy centers in the crystal body. The excitation device 40 can be, for example, a light source, in particular a laser. Alternatively, a large number of vacancy centers can also be present in the crystal body. The optical detection device 50 is designed to detect a fluorescence signal emitted by the crystal body and to provide a measurement signal including the intensity of the fluorescence signal. For example, a combination of a photodiode and a lock-in amplifier is suitable as an optical detection device. Optionally, filters and mirrors and other optical elements can be used to guide the excitation light to the crystal body and / or to guide the fluorescence signal towards the detection device. Instead of one crystal body, a plurality of crystal bodies can also be provided in the form of a crystal body coating.

Claims

1. A measuring system for measuring at least one flow parameter, in particular a time-varying flow parameter, in particular a flow velocity and / or a volume flow rate and / or a mass flow rate, of a fluid measuring substance, in particular a gas, a liquid or a dispersion, flowing in a pipeline, the measuring system comprising: a pipe (3) which can be inserted into the line of the pipeline and has a cavity (3') which is configured to guide the measurement substance flowing in the pipeline or to allow the measurement substance to flow through the cavity; a bluff body (4), in particular a prismatic or cylindrical bluff body, arranged in the cavity (3') of the pipe (3) and configured to move at a shedding frequency Vortexes are generated in the measurement substance flowing through, the shedding frequency being dependent on the current flow rate of the measurement substance , so that a Karman vortex street is formed in the fluid flowing downstream of the bluff body (4); - an eddy current sensor (1), which is arranged downstream of the bluff body (4), the eddy current sensor --Has at least one mechanical resonant frequency , the at least one mechanical resonance frequency is in particular the lowest and / or always higher than the shedding frequency ,and - is configured to generate mechanical oscillations in the vicinity of a static rest position in a manner stimulated by a flowing measurement substance and to provide at least one - in particular electrical or optical - eddy current sensor signal (s1) representative of said oscillations, and --having magnetostrictive material (11); - a magnetic field detection unit (10), which is designed to measure the change of the magnetic field generated by the mechanical force acting on the magnetostrictive material (11), and is designed to provide a magnetic field detection signal (m1) representing the same, in particular an electromagnetic field detection signal or an optical magnetic field detection signal; and converter electronics (2), which are formed in particular by means of at least one microprocessor for analyzing the at least one eddy current sensor signal for determining a measured value of the at least one flow parameter ( ), in particular a digital measured value, and for analyzing functionality and / or plausibility statements about the eddy current sensor signal supplied by the eddy current sensor (1) based on the magnetic field detection signal (m1).

2. The measuring system according to claim 1, in, The eddy current sensor (1) comprises a deformation element (111), in particular a membrane-shaped and / or disk-shaped deformation element, the deformation element having a first surface facing the cavity and an opposite second surface, the second surface in particular being at least partially parallel to the first surface, and The eddy current sensor (1) has at least one transducer element (112), which is arranged above and / or on the second surface of the deformation element (111), in particular, attached to the deformation element (111) and / or located near the deformation element, and the at least one transducer element is configured to detect the movement of the deformation element (111), in particular, the second surface of the deformation element, and convert the movement into the eddy current sensor signal (s1).

3. The measuring system according to claim 2, in, The eddy current sensor (1) has a sensor lug (22), in particular a flat or wedge-shaped sensor lug, which extends from the first surface of the deformation element (111) to a distal end.

4. The measuring system according to claim 2 or 3, in, The deformation element (111) is made of the magnetostrictive material (11), coated with the magnetostrictive material (11), or at least partially covered by a body comprising the magnetostrictive material (11).

5. The measuring system according to claim 3, in, The sensor lug (22) is made of the magnetostrictive material (11), coated with the magnetostrictive material (11) or at least partially covered by a body comprising the magnetostrictive material (11).

6. The measuring system according to claim 4 or 5, in, The deformation element (111) or the sensor lug (22) is provided with a coating made of the magnetostrictive material (11), is made of the magnetostrictive material (11) or is covered by the body comprising the magnetostrictive material (11), at least in a partial region in which the maximum mechanical stress or the maximum deflection occurs during oscillation about the static rest position.

7. The measuring system according to at least one of the preceding claims, in, The magnetic field detection unit (10) is a quantum sensor.

8. The measuring system according to claim 7, in, The quantum sensor has at least one crystal body (30) having at least one magnetic field-sensitive vacancy.

9. The measuring system according to claim 7, in, The quantum sensor includes at least one gas chamber.

10. The measuring system according to claim 8 or 9, in, The magnetic field detection unit (10) comprises an excitation device (40), in particular an optical excitation device, for exciting the vacancy or for exciting the gas chamber, and a detection device (50), in particular an optical detection device, for detecting a magnetic field-related signal of the crystal body (30) or the gas chamber.

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