Sensor element and measurement system produced therewith

Abstract

The invention relates to a sensor element comprising a main part (11) having a main part cavity (11 *); a deformation body (12) made of an electrically conductive material, comprising a deformation cavity (12 *); a reference body (13) made of an electrically conductive material; and a filling body (14) made of a non-conductive (insulating) material comprising a filling body cavity (14 *). The reference body (13) is partially incorporated into the filling body (14) such that the at least one reference body sub-section (13a) is surrounded by the filling body, and the filling body (14) is arranged together with the reference body (13) (incorporated therein) within the main component cavity (11 *) such that the reference body (13) and the main component (11) are mechanically coupled together via the filling body (14) while still being galvanically separated from each other. In addition, the deformation body (12) and the main part (11) are mechanically coupled together so as to form a sensor cavity (1 *) involving the deformation cavity (12 *) such that the main part (11) and the deformation body (12) are connected together so as to establish an electrically conductive connection, and the reference body (13) is partially arranged within the deformation body cavity so as to form a gap (1 ') between the deformation body (12) and the reference body (13). The reference body (13) and the deformation body (12) are arranged such that the deformation body inner surface and the reference body surface are not in contact with each other. Furthermore, the deformation body (12) is designed to perform a vibratory movement about a static rest position, thereby moving relative to the reference body (13), such that the deformation body (12) performs a vibratory movement that changes its cavity or gap (1 '), thereby changing the capacitance C1 that can be measured between the deformation body and the reference body.

Description

Technical Field

[0001] The invention relates to a (capacitive) sensor element, in particular a sensor element for (capacitive) detection of pressure fluctuations in a Karman vortex street formed in a flowing fluid and / or a sensor element designed to be contacted by a flowing fluid. 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 a fluid measuring medium or (measurement) fluid flowing in a pipeline, in particular the flow rate of fast-flowing and / or hot gases (>100°C) and / or fluids with high Reynolds numbers (Re>10,000), or the volume flow rate or mass flow rate corresponding to the corresponding flow velocity (u). Examples of such measuring systems are known in particular from US Pat. No. 4,716,770, US Pat. No. 6,003,384, US Pat. No. 6,910,387, US Pat. No. 6,938,496, US Pat. No. 9,719,819, US Pat. No. 10,845,222 or US Pat. No. 10,948,321 and are also provided in particular by the applicant—for example under the trade names “PROWIRL D 200”, “PROWIRL F 200”, “PROWIRL O 200”, “PROWIRL R 200” (http: / / ptothelideficthese.www.de.endress.comenthelideficthese?filter.text=prowirl).

[0003] Each of the above-mentioned measuring systems has a resistance element which projects into the lumen of a corresponding pipeline (i.e., for example, a system component designed as a heat supply network or a turbine circuit) or into the lumen of a measuring tube used in the process of said pipeline, against which lumen the fluid flows to generate vortices which are aligned 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 form at the resistance element with a separation rate which depends on the flow velocity (1 / )produce.

[0004] Furthermore, the measuring system has a sensor integrated into the resistance element or connected thereto or downstream thereof, i.e. in the region of the Karman vortex street in the flow, thus in the lumen of a projecting (eddy) sensor, which serves to detect 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. for example, an electrical signal or a capacitive electrical signal corresponding to the pressure prevailing in the fluid is provided here, which electrical signal or capacitive electrical signal is subject to periodic fluctuations downstream of the resistance element due to the opposing eddy currents, or has a signal frequency (~ 100 Hz) corresponding to the separation rate of the eddy currents. ).

[0005] For this purpose, the sensor has a (mechanical) sensor component formed by means of a thin, approximately membrane-shaped, approximately disk-shaped deformable body made of metal (measuring membrane) and a sensor pin extending from a substantially flat surface of the deformable body (usually rod-shaped, plate-shaped, wedge-shaped or paddle-shaped), the sensor being designed to measure pressure fluctuations in the Karman vortex street, i.e. to convert them into a movement of the deformable body corresponding to the pressure fluctuations. In particular, the deformable body and the sensor pin are designed to be excited by an (alternating) force acting on the sensor pin, which (alternating) force is dependent on the pressure fluctuations, to force vibrations around a common static rest position, so that the sensor pin performs a pendulum movement that elastically deforms the deformable body.

[0006] The deformable body has an outer edge section, typically circular-ring-shaped, which is configured to seal hermetically, for example, integrally bonded to a socket for holding the deformable body on the wall of a tube, such that the deformable body covers and hermetically seals an opening provided in the wall of the tube, and the surface of the deformable body supporting the sensor pin faces the fluid-carrying lumen of the measuring tube or pipe, and the sensor pin thus protrudes into said lumen. Furthermore, the deformable body is shaped such that at least one (deformed body) thickness (which is measured as the minimum thickness of the inner (deformed body) section bounded by the outer edge section) is much smaller than the (deformed body) diameter (which is measured as the maximum diameter of the surface bounded by the outer edge section). In order to achieve the highest possible measurement sensitivity, i.e. the highest possible sensitivity of the sensor to the pressure fluctuations to be detected, and at the same time, the highest possible mechanical natural or resonant frequency, which for the (bending) vibration modes of the sensor component excited by the pressure fluctuations (other than resonance) is higher than the highest separation rate to be measured, such a deformable body of the established measuring system typically has a diameter to thickness ratio of the order of magnitude of about 20:1. In order to make such sensors or measuring systems formed from them - despite the relatively high diameter to thickness ratio of the correspondingly deformed body required by the measuring principle - also suitable for applications with high operating pressures of more than 10 bar and / or with high operating temperatures of more than 100°C, such as hot steam applications with (measured medium) temperatures of at least temporarily exceeding 200°C and (measured medium) pressures of at least temporarily exceeding 100 bar, or in accordance with relevant pressure equipment directives (such as Directives 97 / 23 / EC, 14 ProdSV, ASUE U-Stamp or 2014 / 68 / EU), the measuring system shown in US-B9719819 also has a flange-like support device with a radial edge zone and a cylindrical axial zone, so that when a predetermined (increasing) pressure is applied, the deformed body is supported on the support device, or the measuring system shown in US-B10845222 also includes an overload protection device for protecting the deformed body from plastic or irreversible deformation by means of a support bracket guided at a lateral distance from the sensor pin and two stops of the sensor pin held by the support bracket. In addition, US-B10948321 shows a measuring system (suitable for high temperature or high pressure) in which the deformed body is shaped so as to achieve a high compressive strength in such a way that at least one area of ​​its surface previously designated to carry the sensor pin (which is adjacent to the sensor pin) is convex.As shown, in particular in US-A6003384, a sensor assembly of the aforementioned type may also have a compensating element, which is generally rod-shaped, planar or sleeve-shaped, extending from a surface of the deformable body facing away from a surface supporting the sensor pin and is particularly used to compensate for forces or moments caused by movements of the sensor assembly (for example, due to vibrations of the pipeline), or to avoid unwanted movements of the sensor pin caused thereby.

[0007] For the purpose of generating the sensor signal, the respective sensor of the aforementioned measuring system further comprises a corresponding converter element, which is positioned directly on and / or in the vicinity of the aforementioned surface of the deformable body facing away from the surface carrying the sensor pins. The converter element is formed by means of a (measuring) capacitor with a variable (measuring) capacitance, which is mechanically coupled to the respective deformable body and is designed to detect a movement of the deformable body or of the compensating body, if present, for example via a corresponding change in the measuring capacitance, and to modulate an electrical carrier signal.

[0008] On the side facing away from the fluid-carrying lumen, the sensor assembly or the sensor formed therewith is also connected to a transducer electronics system, which is usually encapsulated in a pressure-tight and impact-resistant manner and optionally also hermetically sealed toward the outside. The transducer electronics of a measuring system suitable for industrial applications usually have a corresponding digital measuring circuit, which is electrically connected to the transducer element via connecting lines, optionally with an electrical barrier and / or galvanic isolation point or an insert of a feed-through, for processing at least one sensor signal generated by the transducer element and for generating a digital measured value of the measured variable to be detected in each case (i.e., flow velocity, volume flow rate and / or mass flow rate). The transducer electronics system is usually accommodated in a protective housing made of metal and / or impact-resistant plastic. The transducer electronics system of a measuring system suitable for industry or established in industrial measurement technology usually also provides an external interface in accordance with industrial standards (e.g., DIN IEC 60381-1) for communication with a higher-level measuring and / or regulating system (e.g., formed by a programmable logic controller (PLC)). Such an external interface can be designed, for example, as a two-wire connection which can be integrated into a current loop and / or is compatible with established industrial fieldbuses.

[0009] One disadvantage of measuring systems of the aforementioned type is that, due to the relatively high proportion of moving masses (due to the measuring principle) and their unfavorable spatial distribution, their respective sensors may and do routinely have a relatively high or relatively broadband (crossover) sensitivity to interfering vibrations coupled via the pipeline, accompanied by an unfavorable mechanical connection to the respective pipeline; this also routinely causes corresponding (broadband) interfering vibrations of the sensor contacted by the measured medium to also have frequencies in the range of the aforementioned separation rate of the eddy currents, possibly also to have amplitudes of the aforementioned vibration amplitudes comparable to the movement of the deformed body (which correspond to the pressure fluctuations caused by the eddy currents). Another disadvantage of such measuring systems is the high technical effort required for the construction of the (capacitive) converter elements and for the electrical connection of the converter elements to the respective converter electronics, in particular the wiring required therefor. Summary of the invention

[0010] Based on this, it is an object of the present invention to simplify the construction of sensors of the type in question and also to improve them so that they have, on the one hand, a higher pressure and temperature resistance and, on the other hand, a higher measuring sensitivity; this is in particular the case with correspondingly high operating pressures or temperatures and / or at the same time a low cross-sensitivity to any interfering vibrations coupled via the pipeline.

[0011] To achieve this object, the present invention comprises a (capacitive) sensor element, for example, a sensor element for (capacitively) detecting pressure fluctuations in a Karman vortex street formed in a flowing fluid, and / or a sensor element designed to be contacted by a flowing fluid, the sensor element comprising:

[0012] a main part, e.g. sleeve-shaped and / or monolithic, e.g. made of an electrically conductive material and / or metal, having a (main part) cavity with an e.g. circular open first end and an e.g. circular open second end;

[0013] · Deformed bodies, e.g. paddle-shaped and / or integral and / or used as sensor pins, made of conductive material, e.g. with a (operating) temperature of more than An electrical conductivity of S / m, such as a metal, having a (deformed body) cavity having an open first end, such as a circular one, and a closed second end, such as being designed as a blind hole;

[0014] · A reference body, e.g. rod-shaped and / or monolithic, made of an electrically conductive material, e.g. having a conductivity greater than Electrical conductivity in S / m, e.g., metals;

[0015] and a filling body, for example, sleeve-shaped and / or monolithic, made of a non-conductive material, for example, having a conductivity of less than 100% at an (operating) temperature of 20°C. An (insulating) material of electrical conductivity of 2000 S / m, such as glass, plastic or ceramic, having a (filling body) cavity with an open first end, such as a circular shape, and an open second end, such as a circular shape;

[0016] wherein the reference body is partially embedded in the filling body such that at least a first (reference body) subsection of the reference body is surrounded by the filling body, e.g. by forming a friction connection and / or a form fit and / or a material bond, e.g. at least a second (reference body) subsection of the reference body adjacent to the same first reference body subsection is not surrounded by the filling body, and wherein the filling body is arranged (embedded therein) together with the reference body in the main component cavity such that a (main component) surface of the main component facing the lumen of the main component cavity and a (filling body) surface of the filling body facing the same main component surface are in contact with each other, e.g. by forming a friction connection and / or a form fit and / or a material bond, and the reference body and the main component are mechanically coupled to each other via the filling body but are still galvanically separated from each other, e.g. electrically insulated, e.g. such that a minimum resistance R1 between the reference body and the main component at an (operating) temperature of 20°C is not less than 10 MΩ, e.g. greater than 50 MΩ;

[0017] wherein the deformable body and the main part are mechanically coupled to each other to form a sensor cavity containing the deformable body cavity, for example, the sensor cavity contains both the deformable body cavity and the partial area of ​​the main part cavity that is not occupied by the filling body, so that a first (main part) subsection of the main part surrounding a first end of the main part cavity and a first (deformed body) subsection of the deformable body surrounding a first end of the deformable body cavity are connected to each other to form an electrically conductive, for example, gas-tight connection, for example, in a material-bonded and / or form-fitting and / or force-fitting manner, and so that the reference body is arranged proportionally in the deformable body cavity, forming an (annular) gap between the deformable body and the reference body, the (annular) gap being, for example, continuous and / or at least partially in the form of a hollow cylinder and / or not rotationally symmetrical, i.e. having a free second reference body subsection (protruding from the filling body or not surrounded by the filling body) adjacent to the first reference body subsection (13a);

[0018] wherein the reference body and the deformed body are arranged such that a (deformed body) inner surface of the deformed body, i.e. a surface facing the (lumen) of the deformed body cavity, e.g. a (circular) cylindrical surface, and a (reference body) surface of the reference body, i.e. a (circular) cylindrical surface facing the same deformed body inner surface, e.g. only parts of the (circular) cylindrical surface, do not touch each other, e.g. such that the reference body and the deformed body are galvanically separated from each other;

[0019] and wherein the deformable body is designed to perform vibrations about a static resting position, e.g. vibrations forced by (alternating) forces acting on the deformable body, and to move relative to said reference body (13) such that the deformable body can perform or does perform (cantilever) vibrations deforming its (deformable body) cavity or (annular) gap, thereby changing the (sensor) capacitance C1 (of a capacitor formed by the deformable body, the filling body and the reference body), said (sensor) capacitance C1 being measurable between the deformable body and the reference body, e.g. not less than 5 pF and / or not more than 100 pF when the deformable body is in a static resting position.

[0020] Furthermore, the invention also comprises a measuring system formed by means of such a sensor element and (measurement) electronics electrically connected to the same sensor element, which measuring system serves to measure at least one measured variable, for example a flow parameter or a material parameter, of a fluid measured medium, for example a gas and / or a liquid, which is, for example, guided in a pipeline and / or at least temporarily has a (measurement medium) temperature of more than 100° C. and / or acts on a deformable body (of the sensor element) with a pressure difference of more than 10 bar.

[0021] Furthermore, the invention also comprises the use of such a measuring system for measuring flow parameters, such as flow velocity and / or volume flow rate and / or mass flow rate, of a fluid measuring medium, such as steam, flowing in a pipeline, for example, wherein the fluid measuring medium acts on the deformable body (of the sensor element) at a (measuring medium) temperature of more than 100° C. and / or with a pressure difference of more than 10 bar.

[0022] According to a first embodiment of the invention, it is further provided that the deformation body is designed to be in contact with a fluid, such as a liquid and / or a gas or another fluid, such as a fluid that is flowing and / or at least temporarily has a (fluid) temperature of more than 100°C.

[0023] According to a second embodiment of the invention, it is further provided that the deformation body is designed to be surrounded by a flowing fluid, such as a liquid and / or a gas, for example formed as a Karman vortex street, for example to be elastically deformed by (alternating) forces exerted thereon by the fluid.

[0024] According to a third embodiment of the invention, it is further provided that the deformable body is designed to convert (alternating) forces acting thereon, for example exerted by a fluid flowing (around it) and / or introduced via the first and second (deformable body) outer surfaces, into (cantilever) vibrations that deform the (deformable body) cavity or the (annular) gap.

[0025] According to a fourth embodiment of the invention, it is further provided that the deformation body is designed to convert (alternating) forces exerted by a fluid flowing in a (main) flow direction transversely to the (main) flow direction, for example due to pressure fluctuations in a Karman vortex street formed in the flowing fluid, into (cantilever) vibrations, which deform the (deformation body) cavity or the (annular) gap in a vibration direction pointing, for example, transversely to the (main) flow direction and / or in a (main) measuring direction of the sensor element.

[0026] According to a fifth embodiment of the invention, it is further provided that the deformation body is designed to convert an (alternating) force exerted thereon in a (main) measuring direction (of the sensor element) into a (cantilever) vibration that deforms the (deformation body) cavity or gap. According to this embodiment of the invention, it is further provided that the minimum width of the gap extends parallel to the (main) measuring direction or can be measured parallel to the (main) measuring direction and / or the maximum width of the gap does not extend parallel to the (main) measuring direction or cannot be measured parallel to the (main) measuring direction.

[0027] According to a sixth embodiment of the invention, it is further provided that the deformation body has a first (deformation body) outer surface, i.e. a (first) surface facing away from the deformation body cavity, e.g. a convex and / or partially (circular) cylindrical and / or partially flat surface, and a second (deformation body) outer surface, i.e. a (second) surface facing away from the deformation body cavity but still opposite to the first (deformation body) outer surface, e.g. a convex and / or partially (circular) cylindrical and / or partially flat surface. According to this embodiment of the invention, the first and second (deformation body) outer surfaces are also configured to contact a fluid, e.g. a flowing fluid, e.g. a liquid and / or a gas, e.g. in such a way that (alternating) forces generated by the fluid and causing (cantilever) vibrations that deform the (deformation body) cavity or the (annular) gap are introduced into the deformation body via the first and second (deformation body) outer surfaces.

[0028] According to a seventh embodiment of the invention, it is further provided that a (measuring) capacitor having a (sensor) capacitance C1 determined by the gap is formed by means of a deformed body, a filling body and a reference body, for example, such that the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX in the (main) measuring direction of more than 1 pF / mm or is designed to respond to a (deflection) movement ΔX of 1 μm of the deformed body in the (main) measuring direction with a change ΔC1 of the capacitance C1 of more than 1 fF. According to this embodiment of the invention, it is further provided that the sensor element is designed such that the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX in the (main) measuring direction of more than 1 pF / mm and / or a maximum (measuring) sensitivity ΔC1 / ΔX, for example, such that the (measuring) capacitor is arranged to respond to a (deflection) movement ΔX of the deformed body in the (main) measuring direction with a change ΔC1 of the capacitance C1 of more than 1 fF, for example, more than 1 μm. Advantageously, the (measuring) capacitor can also have a cross sensitivity ΔC1 / ΔY, which is different from the (measurement) sensitivity ΔC1 / ΔX in a direction deviating from the (main) measuring direction, for example differs from the (measurement) sensitivity ΔC1 / ΔX by not less than 50%, for example, such that the cross sensitivity ΔC1 / ΔY is smaller than the (measurement) sensitivity ΔC1 / ΔX, and / or such that the (measuring) capacitor is arranged to respond to a (deflection) movement ΔY of the deformed body in at least one, for example each direction deviating from the (main) measuring direction with a change ΔC1' in capacitance C1, which change ΔC1' in capacitance C1 is smaller than a change ΔC1 (of capacitance C1) of the (measuring) capacitor in response to an equal (deflection) movement ΔX of the deformed body in the (main) measuring direction.

[0029] According to an eighth embodiment of the invention, it is further provided that the deformation body and the reference body in the static rest position are at least, for example only partially, arranged coaxially, for example to form a capacitor.

[0030] According to a ninth embodiment of the present invention, it is further provided that the reference body is at least, for example only partially, (circular) cylindrical, for example, so that the minimum (cylindrical) diameter of the second reference body sub-section is greater than 3 mm and / or the minimum (cylindrical) diameter of the first reference body sub-section is greater than the minimum (cylindrical) diameter of the second reference body sub-section.

[0031] According to a tenth embodiment of the present invention, it is further provided that the minimum distance between the deformed body and the reference body is greater than 0.01 mm, for example greater than 0.1 mm, and / or less than 1 mm, for example less than 0.5 mm.

[0032] According to an eleventh embodiment of the present invention, it is further provided that the maximum distance between the deformed body and the reference body is greater than 0.02 mm, for example greater than 0.2 mm, and / or less than 10 mm, for example less than 5 mm.

[0033] According to a twelfth embodiment of the present invention, it is further provided that the minimum width of the (annular) gap (1') is greater than 0.01 mm, for example greater than 0.1 mm, and / or less than 1 mm, for example less than 0.5 mm.

[0034] According to a thirteenth embodiment of the present invention, it is further provided that the maximum width of the (annular) gap (1') is greater than 0.02 mm, for example greater than 0.2 mm, and / or less than 1 mm, for example less than 0.5 mm.

[0035] According to a fourteenth embodiment of the present invention, it is further provided that the maximum width of the (annular) gap (1') is 0.05 mm greater than the minimum width of the (annular) gap (1'), for example, 0.1 mm greater.

[0036] According to a fifteenth embodiment of the present invention, it is further provided that the reference body has a (reference body) mass less than 10 g, for example so that the (sub-segment) mass of the second reference body sub-segment is not greater than 5 g and / or not greater than 60% of the (reference body) mass.

[0037] According to a sixteenth embodiment of the present invention, it is further provided that the deformation body has a minimum wall thickness of not less than 0.2 mm and / or not more than 1 mm.

[0038] According to the seventeenth embodiment of the present invention, it is further provided that the deformation body has a (deformation body) mass less than 50g and / or not less than 4g, for example, so that the (deformation body) mass of the deformation body is greater than the (sub-segment) mass of the second reference body sub-segment.

[0039] According to an eighteenth embodiment of the present invention, it is further provided that the deformation body has a length (of the deformation body) smaller than 50 mm and / or larger than 5 mm.

[0040] According to a nineteenth embodiment of the present invention, it is further provided that the main component has a (main component) length greater than 5 mm and / or less than 100 mm, for example not greater than 50 mm.

[0041] According to a twentieth embodiment of the present invention, it is further provided that the filling body has a length (of the filling body) greater than 5 mm and / or less than 100 mm, for example not greater than 50 mm.

[0042] According to a twenty-first embodiment of the present invention, it is further provided that the reference body has a (reference body) length greater than 10 mm and / or less than 100 mm, for example, such that the (sub-segment) length of the second reference body sub-segment is less than 50 mm and / or greater than 10 mm and / or less than 50% of the (reference body) length and / or greater than 10% of the (reference body) length. Developing this embodiment of the present invention, it is further provided that the main part, the reference body or the filling body is designed such that the filling body length is less than the main part length and / or the filling body length is less than the reference body length and / or the main part length is less than the reference body length.

[0043] According to a twenty-second embodiment of the present invention, it is further provided that the filling body is arranged in the main component cavity so that a partial area of ​​the main component cavity surrounded by the first main component subsection (forming a first end of the main component cavity) is not filled or occupied by the filling body.

[0044] According to a twenty-third embodiment of the invention, it is further provided that the reference body is embedded in the filling body in such a way that a third (reference body) subsegment of the reference body, which is adjacent to the first reference body subsegment but still remote from the second (reference body) subsegment, e.g. rod-shaped, is not surrounded by the filling body. According to this embodiment of the invention, it is further provided that the third (reference body) subsegment (of the reference body) is not rotationally symmetrical with respect to a virtual longitudinal axis of the same (reference body) subsegment, e.g., so that the third (reference body) subsegment has a cross section in the shape of a circular segment.

[0045] According to a twenty-fourth embodiment of the present invention, it is further provided that the sensor element has a plurality of (natural) vibration modes, in which the deformable body and / or the reference body each performs or is capable of performing (mechanical) vibrations around a corresponding static resting position at a corresponding natural or resonant frequency, and the sensor element has a first vibration mode and a second vibration mode, in which the deformable body can perform or does perform (cantilever) vibrations in a first vibration direction, for example having only a single vibration node, and the first vibration direction corresponds to a (main) measuring direction (of the sensor element), for example, and in the second vibration mode, the reference body can perform or does perform (cantilever) vibrations in the same first vibration direction, for example having only a single vibration node, and it is further provided that the natural frequency of the first vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the first vibration mode is for example greater than 1,000 Hz and / or less than 10 kHz, and the natural frequency of the second vibration mode is for example greater than 1,000 Hz and / or less than 10 kHz.

[0046] According to a twenty-fifth embodiment of the present invention, it is further provided that the sensor element has a plurality of (natural) vibration modes, in which the deformation body and / or the reference body each performs or can perform (mechanical) vibrations about a respective static rest position at a respective natural or resonant frequency, the sensor element having:

[0047] a first vibration mode, in which the deformable body can or does perform a (cantilever) vibration, e.g. with only a single vibration node, in a first vibration direction, e.g. corresponding to a (main) measuring direction (of the sensor element),

[0048] a second vibration mode in which the reference body can or does perform a (cantilever) vibration in the same first vibration direction, e.g. with only a single vibration node,

[0049] and a third vibration mode in which the deformed body can or does perform a (cantilever) vibration in a second vibration direction pointing perpendicularly to the first vibration direction, e.g. with only a single vibration node, and a fourth vibration mode in which the reference body can or does perform a (cantilever) vibration in the same second vibration direction, e.g. with only a single vibration node, and further providing that:

[0050] The natural frequency of the first vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the first vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the second vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, and / or

[0051] The natural frequency of the third vibration mode deviates from the natural frequency of the fourth vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the third vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the fourth vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, and / or

[0052] The natural frequency of the third vibration mode deviates from the natural frequency of the first vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the first vibration mode, the natural frequency of the third vibration mode is, for example, greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the first vibration mode is, for example, greater than 1,000 Hz and / or less than 10 kHz, and / or

[0053] The natural frequency of the third vibration mode deviates from the natural frequency of the second vibration mode by less than 1,000 Hz and / or not more than 20% of the natural frequency of the second vibration mode, the natural frequency of the third vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the second vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, and / or

[0054] The natural frequency of the fourth vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the fourth vibration mode being, for example, greater than 1,000 Hz and / or less than 10 kHz, and / or

[0055] The natural frequency of the fourth vibration mode deviates from the natural frequency of the first vibration mode by less than 1,000 Hz and / or not more than 20% of the natural frequency of the first vibration mode, and the natural frequency of the fourth vibration mode is, for example, greater than 1,000 Hz and / or less than 10 kHz, and the natural frequency of the first vibration mode is, for example, greater than 1,000 Hz and / or less than 10 kHz.

[0056] According to a twenty-sixth embodiment of the present invention, it is further provided that the first (reference body) subsection (of the reference body) has a (subsection) length greater than 10 mm and / or less than 100 mm.

[0057] According to a twenty-seventh embodiment of the present invention, it is further provided that the second (reference body) subsection has a (subsection) length greater than 10 mm and / or less than 100 mm.

[0058] According to a twenty-eighth embodiment of the present invention, it is further provided that a second (reference body) sub-section (of the reference body), for example, for increasing the mutual (frequency) distance of natural or resonant frequencies of different vibration modes of the sensor element and / or increasing the (measurement) sensitivity ΔC1 / ΔX of the capacitor C1 formed by the deformed body, the filling body and the reference body relative to the cross sensitivity ΔC1 / ΔY of the same capacitor C1, is not rotationally symmetrical relative to a virtual longitudinal axis of the same (reference body) sub-section, for example, so that the second (reference body) sub-section has a T-shaped cross-section.

[0059] According to a twenty-ninth embodiment of the present invention, it is further provided that the main component is composed of a (linear) thermal expansion coefficient greater than 5⋅ at an (operating) temperature of 20°C. , for example, not less than 8⋅ , and / or less than 25⋅ , for example, no more than 19⋅ Made of material.

[0060] According to a thirtieth embodiment of the present invention, it is further provided that the reference body has a (linear) thermal expansion coefficient at an (operating) temperature of 20°C less than 11⋅ Made of material.

[0061] According to a thirty-first embodiment of the present invention, it is further provided that the filling body is composed of a (linear) thermal expansion coefficient greater than 5⋅ at an (operating) temperature of 20°C. , for example, not less than 8⋅ , and / or less than 25⋅ , for example, no more than 19⋅ Made of material.

[0062] According to a thirty-second embodiment of the present invention, it is further provided that the filling body is composed of a (linear) thermal expansion coefficient greater than 5⋅ at an (operating) temperature of 20°C. , for example, not less than 8⋅ , and / or less than 25⋅ , for example, no more than 19⋅ The main part is made of a material, wherein the thermal expansion coefficient of the main part is not less than the thermal expansion coefficient of the reference body, for example, such that the thermal expansion coefficient of the main part is more than 1⋅ greater than the thermal expansion coefficient of the reference body at an (operating) temperature of 20°C. , especially not less than 5⋅ .

[0063] According to a thirty-third embodiment of the present invention, it is further provided that the filling body is composed of a (linear) thermal expansion coefficient greater than 5⋅ at an (operating) temperature of 20°C. , for example, not less than 8⋅ , and / or less than 25⋅ , for example, no more than 19⋅ The main part is made of a material, wherein the thermal expansion coefficient of the main part is not less than the thermal expansion coefficient of the filling body, for example, such that the thermal expansion coefficient of the main part is more than 1⋅ greater than the thermal expansion coefficient of the filling body at an operating temperature of 20°C. , especially not less than 5⋅ .

[0064] According to a thirty-fourth embodiment of the present invention, it is further provided that the filling body is composed of a (linear) thermal expansion coefficient greater than 5⋅ at an (operating) temperature of 20°C. , for example, not less than 8⋅ , and / or less than 25⋅ , for example, no more than 19⋅ The material of the reference body is made of a material, wherein the thermal expansion coefficient of the reference body is not greater than the thermal expansion coefficient of the filling body, for example, the thermal expansion coefficient of the reference body is not less than 1⋅ smaller than the thermal expansion coefficient of the filling body. .

[0065] According to a thirty-fifth embodiment of the present invention, it is further provided that the main component is, for example, completely made of metal, for example (rust-proof) stainless steel (W No. 1.4404).

[0066] According to a thirty-sixth embodiment of the present invention, it is further provided that the reference body is, for example, completely made of metal, such as a nickel-based alloy (W No. 2.4475).

[0067] According to a thirty-seventh embodiment of the present invention, it is further provided that the filling body at least partially, for example completely, consists of glass, for example molten gas.

[0068] According to the thirty-eighth embodiment of the present invention, it is further provided that the sensor cavity is hermetically sealed.

[0069] According to a thirty-ninth embodiment of the present invention, it is further provided that the main component and the filling body are connected to each other in a force-fitting manner at least at an (operating) temperature of less than 400°C.

[0070] According to a fortieth embodiment of the present invention, it is further provided that the filling body and the reference body are connected to each other in a force-fitting manner at least at an (operating) temperature of less than 400° C.

[0071] According to a forty-first embodiment of the present invention, it is further provided that the sensor cavity is filled with (inert) gas, such as nitrogen and / or an inert gas. Alternatively, the sensor cavity can also be evacuated.

[0072] According to a first development of the invention, the sensor element further comprises a (first) connecting line, which is electrically connected to the reference body, for example electrically conductively connected to the reference body.

[0073] According to a second development of the invention, the sensor element further comprises a (second) connecting line, which is electrically connected to the main component, for example conductively connected to the main component.

[0074] According to a first embodiment of the measuring system according to the invention, the sensor element is further designed to respond to a pressure difference of 1 bar acting on the deformable body in the (main) measuring direction (of the sensor element) with a change ΔC1 of the capacitance C1 of not less than 10 fF (femto Farad) and / or not more than 1 pF (pico Farad).

[0075] According to a second embodiment of the measuring system according to the invention, it is further provided that with the aid of the deformable body, e.g. with the aid of the deformable body and the main component, a reference potential, e.g. zero, is provided for at least one (signal) voltage to be processed with the aid of the measuring electronics, or that a ground (GND) of the measuring electronics is formed.

[0076] The basic idea of ​​the invention is to provide a (capacitive) sensor element with high measurement sensitivity and high pressure and / or temperature resistance, in particular by directly detecting (only) deformation movements of a deforming body relative to a (fixed) reference body placed therein, i.e., a (thin) measuring membrane and a compensating body without following its vibration movement, and converting them (directly) into changes in the (sensor) capacitance or corresponding (capacitive) electrical measurement signals. The sensor element according to the invention has a mechanical and electrical structure that is relatively simple and robust and also advantageously has very small moving masses (due to the measuring principle). In combination with this, the sensor element according to the invention advantageously also has a low cross-sensitivity to external interfering vibrations (e.g., those interfering vibrations coupled via connecting pipes). BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The invention and its advantageous embodiments are explained in more detail below based on the exemplary embodiments shown in the drawings. In all figures, components having the same or the same effect or the same function are provided with the same reference numerals; for the sake of clarity or if it appears reasonable for other reasons, the previously mentioned reference numerals are omitted in the subsequent figures. Further advantageous embodiments or developments, in particular combinations of partial aspects of the invention that were initially only explained individually, further emerge from the figures of the drawings and / or from the claims themselves. In the drawings, in detail:

[0078] Figure 1 shows a perspective side view of an exemplary embodiment of a measuring system according to the invention;

[0079] Figure 2 Shown according to Figure 1 A schematic partial cross-sectional side view of a measurement system;

[0080] Figure 3a It is shown that according to the present invention or suitable for Figure 1 or Figure 2 A side view of an exemplary embodiment of a sensor element of a measurement system;

[0081] Figure 3b The cross-sectional side view shows the Figure 3a or the sensor element of 3b;

[0082] Figure 4a , 4b In a further different side view, the Figure 3aor Figure 3b Sensor elements;

[0083] Figure 5a , 5b Different cross-sectional side views are shown according to Figure 3a or Figure 3b Sensor elements;

[0084] Figure 6a Shown according to Figure 3a a perspective side view of the components (main component, filling body, reference body) of the sensor element; and

[0085] Figure 6b according to Figure 3a A perspective side view of a deformed body of a sensor element is shown. DETAILED DESCRIPTION

[0086] Figure 1 and Figure 2 An exemplary embodiment of a measuring system for measuring at least one flow parameter of a (measurement) fluid flowing in a pipeline, which at least one flow parameter can vary over time, such as a flow velocity v and / or a volume flow rate V', the (measurement) fluid being, for example, a hot gas, which in particular has at least temporarily a temperature of more than 100° C., and / or is at least temporarily under high pressure, in particular more than 10 bar. The pipeline can be designed, for example, as a plant component of a heat supply network or a turbine circuit, and the (measurement) fluid or measurement medium can therefore be, for example, steam, in particular saturated steam or superheated steam, or, for example, (cooling) water or condensate discharged from a steam line. However, the (measurement) fluid can also be, for example, water, (compressed) natural gas, or biogas or gaseous or liquefied hydrogen, so that the pipeline can also be, for example, a component of a natural gas or biogas plant or a high-pressure or liquid hydrogen plant or a gas supply network.

[0087] The measuring system MS has a sensor element 1, in which Figure 3a , 3b , 4a, 4b, 5a, 5b, 6a and 6b show again a sensor element 1, which is enlarged or partially cut away, which sensor element 1 (within a measuring system) can be provided or designed, for example, to detect pressure fluctuations in a (measurement) fluid flowing through the sensor element 1 in the (main) flow direction (of the measuring system MS) and convert them into (capacitive) electrical sensor signals s1 corresponding to the same pressure fluctuations. Figure 1 and Figure 2As shown, when viewed together, the measuring system further comprises a (measurement) electronic system 2, for example housed in a pressure-resistant and / or impact-resistant protective housing 20, which is connected to the sensor element 1 or communicates with the sensor element 1 during operation of the measuring system. The measuring electronics 2 is in particular configured to receive and process the sensor signal s1, i.e., for example, to generate a measurement value representative of at least one flow parameter, i.e., for example, a flow velocity v or a volume flow rate V' . Measurement value It can be visualized, for example, in situ and / or transmitted to an electronic data processing system, such as a programmable logic controller (PLC) and / or a process control station, in a wired manner via a connected fieldbus and / or wirelessly via radio. The protective housing 20 for the measuring electronics 2 can be produced, for example, from metal, such as stainless steel or aluminum, and / or by means of a casting method, such as an investment casting or a pressure die casting method (HPDC); however, it can also be formed, for example, by means of a plastic molded part produced in an injection molding method.

[0088] If respectively Figure 3b and Figure 5a shown in or from Figure 3a , Figure 3b , Figure 4a , Figure 4b , Figure 5a , Figure 5b , Figure 6a and Figure 6bAs is apparent from the combination, the sensor element 1 comprises a main part 11, in particular sleeve-shaped and / or integral, having a (main part) cavity 11*, the (main part) cavity 11* having an open first end, for example circular, and an open second end, in particular, for example; a deformable body 12, in particular paddle-shaped and / or integral, (used as a sensor pin), the deformable body having a (deformable body) cavity 12*, the (deformable body) cavity 12* having an open first end (12a), in particular circular, and a closed second end, in particular designed as a blind hole; a reference body 13, in particular rod-shaped and / or integral, and a filling body 14, in particular sleeve-shaped and / or integral, having a (filling body) cavity 14*, the (filling body) cavity 14* having an open first end, in particular circular, and an open second end, in particular circular. According to a further embodiment of the invention, the deformation body 12 is particularly intended or arranged to be contacted by the (measurement) fluid during operation of the sensor or the measuring system formed thereby, or to be flowed around by a flowing (measurement) fluid, so as to also form a Karman vortex street, in particular in the (main) flow direction of the measuring system; this is in particular in such a way that an (alternating) force (F) is exerted by the fluid on the deformation body 12, which (alternating) force (only) elastically deforms the deformation body 12 or excites it into a (cantilever) vibration (ΔX). The reference body 13 can advantageously be designed to be at least partially (circular) cylindrical; this can also be done, for example, in such a way that the reference body 13 is only partially (circular) cylindrical, as can also be done from Figure 6a See.

[0089] According to another embodiment of the present invention, the main component 11 has a (main component) length L11 greater than 5 mm (millimeter) and / or less than 100 mm, in particular not greater than 50 mm, and / or the filling body has a (filling body) length L14 greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm, and / or the reference body 13 has a (reference body) length L13 greater than 10 mm and / or less than 100 mm. Alternatively or additionally, the filling body length may also be advantageously smaller than the main component length and / or smaller than the reference body length L13, and / or the main component length may be advantageously smaller than the reference body length. According to another embodiment of the present invention, the reference body has a (reference body) mass less than 10 g (grams), and / or the deformed body 12 has a (deformed body) mass not greater than 50 g and / or not less than 4 g.

[0090] The deformation body 12 and the reference body 13 and possibly also the main part 11 consist of an electrically conductive material, in particular a highly conductive material or a material having a conductivity greater than 20°C at an (operating) temperature. S / m (Siemens / meter), such as metal, while the filling body 14 is made of a poorly conductive or non-conductive material, in particular having a conductivity of less than 100 Ω at an (operating) temperature of 20°C. S / m electrical conductivity (insulating) material, such as glass, plastic or ceramic. Advantageously, the main part 11 and the deformed body 12 can also consist of the same material, for example. For example, the main part 11 and the deformed body 12 can also be components of one and the same integrally molded part, for example cast or produced by an additive manufacturing process such as 3-D laser melting; however, the main part 11 and the deformed body 12 can also be designed as individual parts that are initially separated from each other and are only subsequently integrally bonded to each other (for example, welded or brazed to each other), and are therefore produced from materials that can be integrally bonded to each other accordingly.

[0091] According to another embodiment of the invention, the main part 11 is made of a material having a (linear) thermal expansion coefficient at an (operating) temperature of 20°C greater than 5⋅ , especially not less than 8⋅ , and / or less than 25⋅ , especially not more than 19⋅ and / or the reference body 13 is made of a material having a (linear) thermal expansion coefficient of less than 11⋅ at an (operating) temperature of 20°C. and / or the filling body 14 is made of a material having a (linear) thermal expansion coefficient at an (operating) temperature of 20°C greater than 5⋅ , especially not less than 8⋅ and / or less than 25⋅ , especially not more than 19⋅ of a material, in particular, in such a way that the (material) thermal expansion coefficient of the main part 11 is not less than the (material) thermal expansion coefficient of the reference body 13, and / or the (material) thermal expansion coefficient of the main part is not less than the (material) thermal expansion coefficient of the filling body 14, and / or the (material) thermal expansion coefficient of the reference body is not greater than the (material) thermal expansion coefficient of the filling body 14. Advantageously, the material for the main part 11, the reference body 13 or the filling body 14 can also be selected such that the (material) thermal expansion coefficient of the main part is more than 1⋅ greater than the (material) thermal expansion coefficient of the reference body 13 at an (operating) temperature of 20°C. , especially not less than 5⋅ , and / or the coefficient of thermal expansion of the main component is greater than 1⋅ at an (operating) temperature of 20°C than the coefficient of thermal expansion of the filling body 14 , especially not less than 5⋅ , and / or the coefficient of thermal expansion (of the material) of the reference body 13 is less than 1⋅ smaller than the coefficient of thermal expansion (of the material) of the filling body 14 According to another embodiment of the invention, the main part 11 is at least partially, in particular completely, made of metal, for example (rust-proof) stainless steel (W No. 1.4404), and / or the reference body 13 is at least partially, in particular completely, made of metal, for example a nickel-based alloy (W No. 2.4475), and / or the filling body 14 is at least partially, in particular completely, made of glass, for example molten gas.

[0092] In the sensor element according to the invention, the reference body 13 is partially embedded in the filling body 14 so that at least a first (reference body) subsection of the reference body 13 is surrounded by the filling body, in particular by forming a friction connection and / or a form fit and / or a material bond; in particular, at least a second (reference body) subsection of the reference body adjacent to the same first (reference body) subsection is not surrounded by the filling body; this is also done, for example, in such a way that the sensor element is intact at least at an (operating) temperature of 400°C, or the reference body 13 and the filling body 14 are connected to each other in a friction connection at least at an (operating) temperature of 400°C or lower. According to another embodiment of the present invention, the reference body 13 is designed and embedded in the filling body 14 so that the first (reference body) sub-segment 13a (of the reference body) has a (sub-segment) length greater than 10 mm and / or less than 100 mm, and / or the second (reference body) sub-segment 13b (of the reference body) has a (sub-segment) length L13b greater than 10 mm and / or less than 100 mm, and / or a (sub-segment) mass not greater than 5 g. Alternatively or additionally, the minimum (cylindrical) diameter d13b of the above-mentioned second reference body sub-segment 13b may be greater than 3 mm and / or advantageously selected such that the minimum (cylindrical) diameter d13b of the second reference body sub-segment 13b is smaller than the minimum (cylindrical) diameter d13a of the first reference body sub-segment 13a, which also results from Figure 5a or from Figure 3b and 5a and / or the reference body can also be designed and embedded in the filling body 14, so that the aforementioned (sub-segment) length of the second reference body sub-segment is less than 50% of the (reference body) length and / or greater than 10% of the (reference body) length. Advantageously, the reference body 13 can also be designed and embedded in the filling body 14, so that the aforementioned (deformed body) mass is greater than the aforementioned (sub-segment) mass of the second reference body sub-segment, and / or the same (sub-segment) mass of the second reference body sub-segment is not greater than 60% of the (reference body) mass.

[0093] According to another embodiment of the invention, the reference body 13 is also embedded in the filling body such that a third (reference body) subsegment 13c, which is adjacent to the first reference body subsegment 13a but still remote from the second (reference body) subsegment of the reference body, is, for example, (also) rod-shaped and is not surrounded by the filling body 14 (in the same way as the above-mentioned second reference body subsegment). Advantageously, for example, in order to easily mark the installation position, the third (reference body) subsegment 13c can be designed to be non-rotationally symmetrical with respect to a virtual longitudinal axis of the same (reference body) subsegment, for example, such that the third (reference body) subsegment 13c has a circular segment shape or a D-shaped cross section, also as Figure 4b shown.

[0094] The filling body 14 is arranged (embedded therein) together with the reference body 13 in the main component cavity 11*, so that the (main component) surface of the main component facing the tubular cavity of the main component cavity 11* and the (filling body) surface of the filling body facing the same main component surface are in contact with each other (forming a friction connection and / or shape fit and / or material bonding), and the reference body 13 and the main component 11 are mechanically coupled to each other via the filling body 14, but are still galvanically separated from each other, or electrically insulated from each other; for example, this makes the minimum resistance R1 between the reference body 13 and the main component 11 not less than 10MΩ, in particular greater than 50MΩ, at an (operating) temperature of 20°C, and / or makes the main component 11 and the filling body 14 force fit together at least at an (operating) temperature of 400°C or lower. According to another embodiment of the invention, the filling body 14 is further arranged in the main component cavity 11* (at least for protection against mechanical overload or damage) such that a partial area of ​​the main component cavity surrounded by the first main component subsection (forming the first end of the main component cavity) is not filled or occupied by the filling body 14. The main component and the reference body can advantageously be joined by means of primary forming to form the filling body in the main component cavity. Thus, the filling body can be formed, for example, directly in the main component, in that firstly, the reference body is placed in the main component cavity (corresponding to the installation position and location to be achieved) to form a (ring-shaped) gap at a distance from the main component, in which the material (e.g. in the form of granules and / or melt) that can be used to produce the filling body is placed, and then, by solidifying the (filling body) material that is initially at least partially liquid (e.g. partially or molten) in the above-mentioned gap, the filling body is directly formed in the main component cavity.

[0095] The deformation body 12 and the main part 11 are also mechanically coupled to each other to form a deformation body cavity 12*, for example, a sensor cavity 1* (11*+12*), which sensor cavity 1* (11*+12*) involves both the deformation body cavity and the partial area of ​​the main part cavity that is not occupied by the filling body 14, so that a first (main part) subsection of the main part 11 around the first end of the main part cavity and a first (deformed body) subsection of the deformation body 12 around the first end of the deformation body cavity are connected to each other to form an electrically conductive, in particular airtight, connection (in a material-bonded and / or shape-fitting and / or force-fitting manner), and as Figure 5b Shown or also from Figure 3b , 5a and 5b, such that the reference body 13 is arranged proportionally within the deformed body cavity 12, i.e., with a free second reference body subsection 13b adjacent to the first reference body subsection 13a (protruding from the filling body 14 or not surrounded by the filling body 14), a circumferential (annular) gap 1' is formed between the deformed body 12 and the reference body 13. According to another embodiment of the invention, the deformed body 12 and the reference body 13 are further designed and arranged such that the deformed body 12 and the reference body 13 (forming a capacitor) in a static resting position are at least partially arranged coaxially, for example, also in such a way that the deformed body 12 and the reference body 13 are only partially arranged coaxially. Advantageously, furthermore, the sensor cavity 1* can be hermetically sealed, and / or the (annular) gap 1' (as a whole) is not rotationally symmetrical. Alternatively or additionally, the (annular) gap 1' can also be designed to be at least partially hollow cylindrical, for example, in such a way that the (annular) gap 1' is only partially hollow cylindrical. In the above case where the sensor cavity is hermetically sealed, it can also be evacuated , or, for example, filled with an (inert) gas, in particular an inert gas (He, Ar) and / or nitrogen (N).

[0096] like Figure 2As schematically shown, the deformable body 12 and the reference body 13 of the sensor element according to the invention are also arranged such that the (deformable body) inner surface of the deformable body 12, i.e. the (circular) cylindrical surface facing the (lumen) of the deformable body cavity 12*, and the (reference body) surface of the reference body 13 facing the same deformable body inner surface, e.g. only parts of the (circular) cylindrical surface, do not touch each other; this also in particular causes the reference body and the deformable body to be galvanically separated from each other. According to another embodiment of the invention, the reference body and the deformable body are in particular arranged such that the minimum distance a1 between the deformable body 12 and the reference body 13 is greater than 0.01 mm, e.g. also greater than 0.1 mm, and / or less than 1 mm, e.g. also less than 0.5 mm, and / or the maximum distance a2 between the deformable body 12 and the reference body 13 is greater than 0.02 mm, e.g. also greater than 0.2 mm, and / or less than 10 mm, e.g. also less than 5 mm. Alternatively or additionally, the reference body 13 and the deformation body 12 can also be advantageously arranged so that the minimum width b1 of the (annular) gap 1' is greater than 0.01 mm, in particular greater than 0.1 mm, and / or less than 1 mm, in particular less than 0.5 mm, and / or the maximum width b2 of the (annular) gap 1' is greater than 0.02 mm, in particular greater than 0.2 mm, and / or less than 1 mm, in particular less than 0.5 mm, and / or the above-mentioned maximum width b2 of the (annular) gap 1' is greater than the above-mentioned minimum width b1 of the (annular) gap 1' by more than 0.05 mm, in particular more than 0.1 mm. For example, based on the following calculation rule,

[0097]

[0098] The nominal (measured) capacitance C1 of the sensor element (in the static rest position) can also be specified approximately (in advance) or determined (subsequently), wherein the sensor element-specific (dimensionless) coefficient K1 is advantageously selected to be not less than 0.5 and / or not greater than 3, or in the case where the sensor element 1 corresponds to a (ideal) cylindrical capacitor, to be equal to 2π (K1 = 2π = 2⋅3.1415...).

[0099] According to another embodiment of the invention, the deformation body 12 further comprises a first (deformation body) outer surface 12', i.e. a (first) surface facing away from the deformation body cavity 12*, for example, an at least partially convex and / or partially (circular) cylindrical and / or partially flat surface, and a second (deformation body) outer surface 12'', i.e. a (second) surface facing away from the deformation body cavity 12* but still opposite to the first (deformation body) outer surface, in particular a surface at least partially convex and / or partially (circular) cylindrical and / or partially flat and / or structurally identical to the first (deformation body) outer surface. The first and second (deformation body) outer surfaces are in particular designed to contact the (measurement) fluid, so that the (alternating) force F(t) generated by the fluid, in particular deforming the (deformation body) cavity or the (annular) gap 1' and causing (cantilever) vibrations, is introduced into the deformation body via the first and second (deformation body) outer surfaces. The first and second (deformation body) outer surfaces can also advantageously be designed and arranged such that at least one surface normal of the first outer surface is aligned with an opposite surface normal of the second outer surface, or the surface normals of the first and second outer surfaces are parallel to each other, in particular coincident. The deformation body 12 can also be designed externally, as is quite common with such sensors or measuring systems formed therewith, for example, as a wedge or at least partially plate-shaped; this can also be done, for example, in such a way that the first and second outer surfaces are at least partially (plane) parallel and / or at least partially antiparallel.

[0100] In the sensor element according to the invention, the deformable body 12 is also particularly designed to perform vibrations about a static rest position, for example, forced by an (alternating) force acting on the deformable body 12 to elastically deform or move relative to the reference body 13, so that the deformable body 12 can perform or does perform a (cantilever) vibration ΔX(t), which (cantilever) vibration ΔX(t) deforms its (deformable body) cavity 12* or the (annular) gap 1', thereby changing the (sensor) capacitance C1 (of the capacitor formed by the deformable body 12, the filling body 14 and the reference body 13), which is measurable between the deformable body 12 and the reference body 13, in particular when the deformable body is in a static rest position, and is not less than 5 pF and / or not more than 100 pF in total.

[0101] As already indicated, the aforementioned (alternating) force F(t) exerted on the deformation body 12 can be generated, for example, by contacting the deformation body 12 or by a (measurement) fluid flowing around the deformation body 12, or introduced via the aforementioned first and second (deformation body) outer surfaces. For the electrical connection to the aforementioned (measurement) electronics 2, the sensor element 1 according to a further embodiment further comprises a (first) connection line 11, which is electrically connected to the reference body 13, in particular electrically conductively connected to the reference body 13. Furthermore, the sensor element can also have, for example, a further (second) connection line 12, which is also used for the electrical connection to the (measurement) electronics, which can advantageously be electrically connected to the main part 11 or electrically conductively connected to the main part 11. Alternatively or additionally, a reference potential, in particular zero, can be provided for at least one (signal) voltage processed by the measurement electronics, or advantageously, a ground (GND) of the measurement electronics 2 can also be formed, by means of the deformation body 12 or by means of the deformation body 12 and the main part 11.

[0102] According to another embodiment of the invention, the deformation body 12 is also designed to convert an (alternating) force F(t) exerted by the (measuring) fluid flowing in the (main) flow direction of the (measuring system) transversely to the (main) flow direction, for example due to pressure fluctuations in the Karman vortex street formed in the flowing fluid, into a (cantilever) vibration X(t), which deforms the (deformation body) cavity or the (annular) gap 1' in the vibration direction, in particular transversely to the (main) flow direction z and / or in the (main) direction or measuring direction x of the sensor element 1. The sensor element 1 or the measuring system formed thereby can advantageously be designed or aligned such that the minimum width of the gap 1' extends parallel to the aforementioned (main) measuring direction x or can be measured parallel to the (main) measuring direction x and / or the maximum width of the gap 1' does not extend parallel to the aforementioned (main) measuring direction x or cannot be measured parallel to the (main) measuring direction x. Alternatively or additionally, the sensor element may advantageously be arranged such that the surface normals of the aforementioned first and second (deformation body) outer surfaces are aligned at least partially parallel to the aforementioned (main) measuring direction x and / or at least partially orthogonal to the aforementioned (main) flow direction z.

[0103] According to another embodiment of the invention, the deformable body 12 further has a (deformed body) thickness D12, measured as the maximum extension (of the deformable body 12) in the direction of the aforementioned (main) detection direction x of the sensor element 1, or as the maximum distance between the aforementioned first outer surface and the second outer surface, which is significantly smaller than the (deformed body) length L12 of the deformable body 12, which is measured as the (maximum) extension (of the deformable body 12) in the direction (y) of the aforementioned main component length L11 or reference body length L13, or as the minimum distance between the aforementioned open first end of the deformable body cavity 12* and the aforementioned closed second end of the deformable body cavity 12*, plus the local wall thickness of the deformable body 12. Furthermore, the deformable body 12 has a (deformed body) width B12 measured in a direction (z) orthogonal to both the direction (x) of the (deformed body) thickness D12 and the direction (y) of the (deformed body) length L12, which is larger than the (deformed body) thickness D12. Advantageously, the (deformed body) width B12 can also be selected such that it is smaller than the (deformed body) length L12. Alternatively or additionally, the (deformed body) length L12 is not less than 5 mm and / or not more than 50 mm, and / or the deformed body 12 has a minimum (deformed body) wall thickness w12 of not less than 0.2 mm and / or not more than 1 mm. Advantageously, the deformed body 12 can also be designed or arranged such that the aforementioned minimum (deformed body) wall thickness w12 is located in at least one subsection of the deformed body 12 adjacent to the lumen of the deformed body cavity 12* and comprising one of the aforementioned first and second outer surfaces, or measured in the aforementioned (main) detection direction x of the sensor element 1.

[0104] As already indicated, in the sensor element according to the invention, a (measuring) capacitor is formed in particular by means of the deformation body 12, the filling body 14 and the reference body 13; this is in particular in such a way that the same (measuring) capacitor has a (sensor) capacitance C1 which is also determined by the (annular) gap. According to a further embodiment of the invention, the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX of greater than 1 pF / mm (picofarad per millimeter) in the aforementioned (main) measuring direction, or the (measuring) capacitor is arranged to respond to a (deflection) movement ΔX of 1 μm (micrometer) of the deformation body 12 in the aforementioned (main) measuring direction with a change ΔC1 of the capacitance C1 of greater than 1 fF (femtofarad). Advantageously, the (measuring) capacitor or the sensor element formed therewith can also be designed so that the capacitor has a maximum (measuring) sensitivity ΔC1 / ΔX in the aforementioned (main) measuring direction, in particular greater than 1pF / mm; this is in particular in such a way that the (measuring) capacitor responds to a (deflection) movement ΔX of the deformed body 12 in the aforementioned (main) measuring direction of greater than 1μm and / or less than 5μm with a change ΔC1 in capacitance C1 of greater than 1fF. Alternatively or additionally, the (measuring) capacitor or the sensor element formed therewith can advantageously be designed such that the (measuring) capacitor has a cross sensitivity ΔC1 / ΔY in a direction deviating from the (main) measuring direction, which is different from the (measurement) sensitivity ΔC1 / ΔX, for example, differs from the (measurement) sensitivity ΔC1 / ΔX by not less than 50%; this is also particularly in such a way that the cross sensitivity ΔC1 / ΔY is smaller than the (measurement) sensitivity ΔC1 / ΔX, in particular differs by not less than 50% of the (measurement) sensitivity ΔC1 / ΔX, and / or such that the (measuring) capacitor responds to a (deflection) movement ΔY of the deformable body 12 in at least one, in particular in each direction deviating from the (main) measuring direction, with a change ΔC1' in capacitance C1, in particular greater than 1 μm, and the change ΔC1' in capacitance C1 is smaller than the change ΔC1 (of capacitance C1) of the (measuring) capacitor in response to the (deflection) movement ΔX of the deformable body 12 in the (main) measuring direction x.

[0105] Due to its specific design, the sensor element 1 also has, in particular, a large number of (natural) vibration modes, in which the deformation body 12 and / or the reference body 13 each perform or can perform mechanical vibrations about a respective static rest position at a respective (mechanical) natural or resonant frequency; this is in particular in such a way that the sensor element 1 has a first vibration mode, in which the deformation body 12 can or does perform (cantilever) vibrations in a first vibration direction, which for example also corresponds to the aforementioned (main) measuring direction (of the sensor element), and a second vibration mode, in which the reference body 13 can or does perform (cantilever) vibrations in the same first vibration direction. The vibrations according to the first vibration mode and / or the second vibration mode can also be designed in particular such that they each have a natural frequency greater than 1,000 Hz (Hertz) and / or less than 10 kHz (Kilohertz), and / or have only a single vibration node. According to another embodiment of the invention, the deformable body 12 and the reference body 13 are further coordinated with each other, at least in order to avoid (interfering) vibrations that change the (sensor) capacitance in an undesired manner (e.g. at a frequency corresponding to one of the first and second natural frequencies) and thus falsify the actual measurement, so that the natural frequency of the first vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode. In addition to the aforementioned first and second vibration modes, the sensor element may also have a third vibration mode, in which the deformable body 12 is able to perform or does perform a (cantilever) vibration in a second vibration direction pointing perpendicular to the aforementioned first vibration direction, e.g. with only a single vibration node, and the sensor element may also have a fourth vibration mode, in which the reference body 13 is able to perform or does perform a (cantilever) vibration in the same second vibration direction, e.g. with only a single vibration node.The vibrations according to the third and / or fourth vibration mode can, for example, be designed so that they each have a natural frequency greater than 1,000 Hz and / or less than 10 kHz; in order to avoid any interfering vibrations that could be caused by this; this is also advantageously done in such a way that the natural frequency of the third vibration mode deviates from the natural frequency of the fourth vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, and / or the natural frequency of the third vibration mode deviates from the natural frequency of the first vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the first vibration mode, and / or the natural frequency of the third vibration mode deviates from the natural frequency of the second vibration mode by less than 1,000 Hz and / or not more than 20% of the natural frequency of the second vibration mode, and / or the natural frequency of the fourth vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, and / or the natural frequency of the fourth vibration mode deviates from the natural frequency of the first vibration mode by less than 1,000 Hz and / or not more than 20% of the natural frequency of the first vibration mode. For example, by appropriately selecting the (geometric) dimensions of the reference body 13 and the deformed body 12, in particular their respective length, the deformed body wall thickness, the deformed body thickness or the reference body diameter etc., as well as their respective material or mass, the aforementioned natural frequency can be specifically adjusted. According to another embodiment of the invention, the second (reference body) subsection 13b (of the reference body 13), for example, for increasing the mutual (frequency) distance of the natural or resonant frequencies of different vibration modes of the sensor element and / or for increasing the aforementioned (measurement) sensitivity ΔC1 / ΔX relative to the aforementioned cross sensitivity ΔC1 / ΔY, is not rotationally symmetrical relative to a virtual longitudinal axis of the same (reference body) subsection 13b, for example, so that the second (reference body) subsection 13b has a T-shaped cross section, also as Figure 5b Or as shown in 6a.

[0106] According to another embodiment of the present invention, the measuring system MS further comprises a tube 3 which can be inserted into the process of the aforementioned pipeline and has a lumen 3' which is surrounded by a wall 3* (e.g., a metal wall) of the tube and extends from an inlet end 3+ to an outlet end 3# and is configured to guide the fluid flowing in the pipeline. Figure 2 and Figure 5aIn the exemplary embodiment shown, both at the inlet end 3+ and at the outlet end 3# there is a flange, which serves in each case to form a leak-free flange connection with a corresponding flange on the inlet-side or outlet-side pipeline section of the pipeline. Moreover, the tube 3 here is essentially straight, i.e., for example, in the form of a hollow cylinder with a circular cross section, in such a way that the tube 3 has a virtual straight longitudinal axis L3 connecting the inlet end 3+ and the outlet end 3+. The sensor element 1 is inserted from the outside into the lumen of the tube 3 through an opening 3'' formed in the wall and is fixed in the region of the same opening, for example, also detachably fixed to the wall 3* from the outside, in such a way that the deformation body 12 protrudes into the same lumen. In particular, the sensor element 1 is inserted into the opening 3'' in such a way that a substantially membrane-like (deformation body) subsection 12a of its deformation body 12 covers or hermetically seals the opening 3''. The opening 3'' can also, for example, be designed such that it has an (inner) diameter in the range between 10 mm and about 50 mm, as is very common in measuring systems of the type in question. According to a further embodiment of the invention, a socket for holding the sensor element 1 or its deformable body 12 on the wall 3* is also formed in the opening 3''. In this case, the sensor element 1 can be fixed to the tube 3, for example, by an integral joining of the deformable body 12 and the wall 3*, in particular by welding or brazing; however, it can also, for example, be detachably connected to the tube 3, i.e., for example screwed into or onto it. Furthermore, at least one sealing surface (e.g. also a circumferential or annular sealing surface) can be formed in the aforementioned socket and be configured to cooperate with the deformable body 12 or its aforementioned (deformable body) subsection 12a and the optionally provided (e.g. annular or annular disc-shaped) sealing element to seal the opening 3''. At least for the above-mentioned case in which the sensor element 1 is inserted into the above-mentioned retainer and / or the deformable body 12 is to be connected to the wall 3* of the tube 3 in a material-bonded manner, another sealing surface matching the sealing surface (for example, in the form of a ring) can advantageously be formed into the deformable body 12 or its (deformable body) sub-section 12a in the edge area (outside, or corresponding to the above-mentioned sealing surface of the retainer).

[0107] exist Figure 2In the exemplary embodiment shown, the measuring system is designed in particular as a vortex flow meter having a resistance element 4 arranged in the lumen of the tube 3 - here, ie upstream of the (mounted) sensor element 1 - and for generating a Karman vortex channel in the flowing fluid. Here, in particular, the sensor element 1 and the resistance element 4 are dimensioned and arranged such that the deformation body 12 protrudes into the lumen 3* of the tube 3 or into the fluid conducted therein in a region which is regularly occupied by a (fixedly formed) Karman vortex street during operation of the measuring system, so that the alternating forces acting on the deformation body 12 or the pressure fluctuations detected by means of the sensor 1 are periodic pressure fluctuations caused by the vortex with a separation rate (~1 / )) falls off at the resistor element 4, and the sensor signal s1 has a signal frequency (~) corresponding to the separation rate of the eddy current. ). Furthermore, in the exemplary embodiment shown here, the measuring system is designed as a compact measuring system or a vortex flowmeter, wherein the measuring electronics 2 is accommodated in a protective housing 20 which is held on the tube 3, for example, by means of a neck-shaped connection 30. According to another embodiment of the invention, the dimensions of the sensor element 1 and the tube 3 are further designed so that the aforementioned deformed body length L12 corresponds to more than half of the diameter DN of the tube 3 or less than 95% of the same diameter DN. For example, the deformed body length L12 can also be selected so that the free end of the deformed body 12 corresponding to the aforementioned second end of the deformed body cavity 12 is also only at a very small minimum distance from the wall 3* of the tube 3, which is common for relatively small diameters of less than 50 mm, or can also be as Figure 2 For example, in the case of a relatively large tube diameter of 50 mm or more, the deformation body length L12 can also be significantly shorter than half the diameter DN of the tube 3 , as is very common in the case of measuring systems of the type in question.

Claims

1. A (capacitive) sensor element, in particular a sensor element for (capacitively) detecting pressure fluctuations in a Karman vortex street formed in a flowing fluid and / or a sensor element designed to be contacted by a flowing fluid, the sensor element comprising: - a main part (11), in particular sleeve-shaped and / or monolithic, in particular made of an electrically conductive material and / or metal, comprising a (main part) cavity (11*) having a first, in particular circular, open end and a second, in particular circular, open end; - a deformation body (12), in particular paddle-shaped and / or integral and / or used as a sensor pin, made of an electrically conductive material, in particular having a conductivity greater than 0.05 at an (operating) temperature of 20°C. S / m electrical conductivity, in particular metal, the deformed body having a (deformed body) cavity (12*), the (deformed body) cavity (12*) having an open first end, in particular circular, and a closed second end, in particular designed as a blind hole; - a reference body (13), in particular rod-shaped and / or monolithic, made of an electrically conductive material, in particular having a conductivity greater than 0.05 at an (operating) temperature of 20°C. S / m electrical conductivity, especially for metals; - and the filling body (14), in particular sleeve-shaped and / or monolithic, is made of a non-conductive material, in particular having a conductivity of less than 0.1% at an (operating) temperature of 20°C. S / m electrical conductivity (insulating) material, in particular glass, plastic or ceramic, the filling body having a (filling body) cavity (14*), the (filling body) cavity (14*) having a first, in particular circular, open end and a second, in particular circular, open end; - wherein the reference body (13) is partially embedded in the filling body (14), in particular by forming a friction connection and / or a form fit and / or a material connection, so that at least a first (reference body) subsection (13a) of the reference body (13) is surrounded by the filling body; in particular, at least a second (reference body) subsection (13b) of the reference body (13) adjacent to the same first reference body subsection is not surrounded by the filling body (14); - and wherein the filling body (14) is arranged (embedded therein) together with the reference body (13) in the main part cavity (11*), - a (main component) surface of the main component (11) facing the lumen of the main component cavity (11*) and a (filling body) surface of the filling body (14) facing the same main component surface are brought into contact with each other, in particular by forming a friction connection and / or a form fit and / or a material bond, - and the reference body (13) and the main part (11) are mechanically coupled to each other via the filling body (14), but are still galvanically separated from each other, in particular electrically insulated, in particular such that at an (operating) temperature of 20°C a minimum resistance R1 between the reference body (13) and the main part (11) is not less than 10 MΩ, in particular greater than 50 MΩ; - wherein the deformable body (12) and the main part (11) are mechanically coupled to each other to form a deformable body cavity (12*), in particular a sensor cavity (1*) comprising both the deformable body cavity (12*) and a partial area of ​​the main part cavity (11*) not occupied by the filling body (14), - a first (main component) subsection of the main component (11) surrounding the first end of the main component cavity (11*) and a first (deformed body) subsection of the deformed body (12) surrounding the first end of the deformed body cavity (12*) are connected to each other, in particular in a material-bonded and / or form-fitting and / or force-fitting manner, to form an electrically conductive, in particular airtight, connection, - and such that the reference body (13) is arranged in the deformed body cavity, forming an (annular) gap (1') between the deformed body (12) and the reference body (13), in particular a circumferential gap and / or an at least partially hollow cylindrical gap and / or a rotationally asymmetric gap, i.e. having a free second reference body section (13b) adjacent to its first reference body section (13a) (protruding from the filling body or not surrounded by the filling body); - wherein the reference body (13) and the deformable body (12) are arranged such that the (deformed body) inner surface of the deformable body (12), i.e. the surface facing (the lumen) of the deformable body cavity, in particular a (circular) cylindrical surface, and the (reference body) surface of the reference body (13), i.e. the surface facing the same deformable body inner surface, in particular only a part of the (circular) cylindrical surface, do not touch each other, in particular such that the reference body (13) and the deformable body (12) are galvanically separated from each other; - and wherein the deformable body (12) is designed to perform vibrations around a static rest position, in particular vibrations forced by (alternating) forces acting on the deformable body (12), and to move relative to the reference body (13) so that the deformable body (12) can perform or does perform (cantilever) vibrations that deform its (deformable body) cavity or the (annular) gap (1'), thereby changing the (sensor) capacitance C1 (of the capacitor formed by the deformable body, the filling body and the reference body), the (sensor) capacitance C1 being measurable between the deformable body and the reference body, in particular not less than 5 pF and / or not more than 100 pF when the deformable body is in a static rest position.

2. The sensor element according to claim 1, wherein: The deformation body is designed to come into contact with a fluid, in particular a liquid and / or a gas or other fluid, in particular a fluid that is flowing and / or at least temporarily has a (fluid) temperature of more than 100°C.

3. The sensor element according to claim 1, wherein: The deformation body is designed to be surrounded by a flowing fluid, in particular a fluid and / or a gas, formed as a Karman vortex street, and to be elastically deformed, in particular by an (alternating) force exerted thereon by the fluid.

4. The sensor element according to claim 1, wherein: The deformable body is designed to convert (alternating) forces acting on it, in particular exerted by a fluid flowing (around it) and / or introduced via the first and second (deformable body) outer surfaces, into (cantilever) vibrations that deform the (deformable body) cavity or the (annular) gap.

5. The sensor element according to claim 1, wherein: The deformation body is designed to convert (alternating) forces exerted by a fluid flowing in a (main) flow direction transversely to the (main) flow direction, in particular due to pressure fluctuations in a Karman vortex street formed in the flowing fluid, into (cantilever) vibrations, which cause the (deformation body) cavity or the (annular) gap to deform in a vibration direction, in particular transversely to the (main) flow direction and / or in a (main) measuring direction of the sensor element.

6. The sensor element according to claim 1, wherein: The deformation body has a first (deformation body) outer surface, i.e. a (first) surface facing away from the deformation body cavity, in particular a convex and / or partially (circular) cylindrical and / or partially flat surface, and a second (deformation body) outer surface, i.e. a (second) surface facing away from the deformation body cavity but still opposite to the first (deformation body) outer surface, in particular a convex and / or partially (circular) cylindrical and / or partially flat surface.

7. Sensor element according to the preceding claim, wherein The first and second (deformation body) outer surfaces are designed to contact a fluid, in particular a flowing fluid, in particular a liquid and / or a gas, in particular so that (alternating) forces generated by the fluid and causing (cantilever) vibrations that deform the (deformation body) cavity or the (annular) gap are introduced into the deformation body via the first and second (deformation body) outer surfaces.

8. The sensor element according to claim 1, wherein: The deformation body is designed to convert an (alternating) force exerted on it in the (main) measuring direction (of the sensor element) into a (cantilever) vibration which deforms the (deformation body) cavity or the gap.

9. Sensor element according to the preceding claim, - in, The minimum width of the gap (1') extends parallel to the (main) measuring direction or is measurable parallel to the (main) measuring direction; and / or - wherein the maximum width of the gap (1') does not extend parallel to the (main) measuring direction or cannot be measured parallel to the (main) measuring direction.

10. The sensor element according to one of the preceding claims, wherein A (measuring) capacitor having a (sensor) capacitance C1 determined by the gap is formed by means of the deformable body, the filling body and the reference body, in particular so that the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX greater than 1 pF / mm in a (main) measuring direction, or is designed to respond to a 1 μm (deflection) movement ΔX of the deformable body in the (main) measuring direction with a change ΔC1 of the capacitance C1 greater than 1 fF.

11. Sensor element according to the preceding claim, wherein The (measuring) capacitor has in the (main) measuring direction a maximum (measuring) sensitivity ΔC1 / ΔX, in particular greater than 1 pF / mm, such that the (measuring) capacitor is arranged to respond to a (deflection) movement ΔX, in particular greater than 1 μm, of the deformable body in the (main) measuring direction with a change ΔC1 in capacitance C1, in particular greater than 1 fF.

12. Sensor element according to the preceding claim, wherein The (measuring) capacitor has a cross sensitivity ΔC1 / ΔY, which is different from the (measurement) sensitivity ΔC1 / ΔX in a direction deviating from the (main) measuring direction, in particular differs from the (measurement) sensitivity ΔC1 / ΔX by not less than 50%, in particular such that the cross sensitivity ΔC1 / ΔY is smaller than the (measurement) sensitivity ΔC1 / ΔX, and / or such that the (measuring) capacitor is arranged to respond to a (deflection) movement ΔY of the deformable body in at least one, in particular each direction deviating from the (main) measuring direction with a change ΔC1' in the capacitance C1, which is smaller than a change ΔC1 (of the capacitance C1) of the (measuring) capacitor in response to an equal (deflection) movement ΔX of the deformable body in the (main) measuring direction.

13. Sensor element according to one of the preceding claims, - wherein the deformation body and the reference body in the static rest position, in particular forming a capacitor, are arranged at least, in particular only partially, coaxially; and / or - in, The reference body is at least, in particular only partially, (circular) cylindrical, in particular such that the smallest (cylindrical) diameter of the second reference body subsection is greater than 3 mm and / or the smallest (cylindrical) diameter of the first reference body subsection is greater than the smallest (cylindrical) diameter of the second reference body subsection; and / or - wherein the minimum distance between the deformed body and the reference body is greater than 0.01 mm, in particular greater than 0.1 mm, and / or less than 1 mm, in particular less than 0.5 mm; and / or - wherein the maximum distance between the deformed body and the reference body is greater than 0.02 mm, in particular greater than 0.2 mm, and / or less than 10 mm, in particular less than 5 mm; and / or - wherein the minimum width of the (annular) gap (1') is greater than 0.01 mm, in particular greater than 0.1 mm, and / or less than 1 mm, in particular less than 0.5 mm; and / or - wherein the maximum width of the (annular) gap (1') is greater than 0.02 mm, in particular greater than 0.2 mm, and / or less than 1 mm, in particular less than 0.5 mm; and / or - wherein the maximum width of the (annular) gap (1') is 0.05 mm greater, in particular 0.1 mm greater, than the minimum width of the (annular) gap (1'); and / or - wherein the reference body has a (reference body) mass of less than 10 g, in particular such that the (sub-segment) mass of the second reference body sub-segment is not more than 5 g and / or not more than 60% of the (reference body) mass; and / or - wherein the deformed body has a minimum wall thickness of not less than 0.2 mm and / or not more than 1 mm; and / or - wherein the deformable body has a (deformable body) mass of less than 50 g and / or not less than 4 g, in particular such that the (deformable body) mass of the deformable body is greater than the (sub-segment) mass of the second reference body sub-segment; and / or - wherein the deformation body has a length (of the deformation body) of less than 50 mm and / or greater than 5 mm.

14. Sensor element according to one of the preceding claims, - in, The main part has a (main part) length greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm; and / or - wherein the filling body has a (filling body) length of more than 5 mm and / or less than 100 mm, in particular not more than 50 mm; and / or - wherein the reference body has a (reference body) length greater than 10 mm and / or less than 100 mm, in particular such that a (sub-segment) length of a sub-segment of the second reference body is less than 50 mm and / or greater than 10 mm and / or less than 50% of the (reference body) length and / or greater than 10% of the (reference body) length.

15. Sensor element according to the preceding claim, - in, The filling body length is less than the main part length; and / or - wherein the filling body length is less than the reference body length; and / or - wherein the main component length is less than the reference body length.

16. The sensor element according to one of the preceding claims, wherein The filling body is arranged in the main component cavity such that a partial area of ​​the main component cavity enclosed by the first main component subsection (forming the first end of the main component cavity) is not filled or occupied by the filling body.

17. The sensor element according to one of the preceding claims, wherein The reference body is embedded in the filling body such that a third, in particular rod-shaped, subsection of the reference body, which is adjacent to the first reference body subsection but still remote from the second (reference body) subsection, is not enclosed by the filling body.

18. Sensor element according to the preceding claim, wherein The third (reference body) subsection (of the reference body) is not rotationally symmetrical with respect to a virtual longitudinal axis of the same (reference body) subsection, in particular such that the third (reference body) subsection has a circular segment-shaped cross section.

19. The sensor element according to one of the preceding claims, wherein The sensor element has a plurality of (natural) vibration modes in which the deformation body and / or the reference body each executes or can execute a (mechanical) vibration about a respective static rest position at a respective natural or resonant frequency.

20. Sensor element according to the preceding claim, - in, the sensor element having a first vibration mode, in which the deformable body can or does perform a (cantilever) vibration in a first vibration direction, in particular having only a single vibration node, and a second vibration mode, in which the reference body can or does perform a (cantilever) vibration in the same first vibration direction, in particular having only a single vibration node; - and wherein the natural frequency of the first vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the first vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, and the natural frequency of the second vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz.

21. Sensor element according to the preceding claim, - in, The sensor element has a third vibration mode, in which the deformable body can or does perform a (cantilever) vibration in a second vibration direction pointing perpendicularly to the first vibration direction, in particular having only a single vibration node, and a fourth vibration mode, in which the reference body can or does perform a (cantilever) vibration in the same second vibration direction, in particular having only a single vibration node.

22. Sensor element according to the preceding claim, - wherein the natural frequency of the third vibration mode deviates from the natural frequency of the fourth vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the third vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the fourth vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, and / or - in, The natural frequency of the third vibration mode deviates from the natural frequency of the first vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the first vibration mode, the natural frequency of the third vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the first vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, and / or - wherein the natural frequency of the third vibration mode deviates from the natural frequency of the second vibration mode by less than 1,000 Hz and / or not more than 20% of the natural frequency of the second vibration mode, the natural frequency of the third vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, the natural frequency of the second vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, and / or - wherein the natural frequency of the fourth vibration mode deviates from the natural frequency of the second vibration mode by less than 500 Hz and / or not more than 10% of the natural frequency of the second vibration mode, the natural frequency of the fourth vibration mode being in particular greater than 1,000 Hz and / or less than 10 kHz, and / or - wherein the natural frequency of the fourth vibration mode deviates from the natural frequency of the first vibration mode by less than 1,000 Hz and / or not more than 20% of the natural frequency of the first vibration mode, the natural frequency of the fourth vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz, and the natural frequency of the first vibration mode is in particular greater than 1,000 Hz and / or less than 10 kHz.

23. Sensor element according to one of the preceding claims, - in, The first (reference body) subsection (of the reference body) has a (subsection) length of more than 10 mm and / or less than 100 mm; and / or - wherein the second (reference body) sub-section (of the reference body) has a (sub-section) length of more than 10 mm and / or less than 100 mm; and / or - wherein the second (reference body) subsection (of the reference body), in particular for increasing the mutual (frequency) distance of natural or resonant frequencies of different vibration modes of the sensor element and / or for increasing the (measurement) sensitivity ΔC1 / ΔX of the capacitor C1 formed by the deformation body, the filling body and the reference body relative to the cross sensitivity ΔC1 / ΔY of the same capacitor C1, is not rotationally symmetrical relative to a virtual longitudinal axis of the same (reference body) subsection, in particular so that the second (reference body) subsection has a T-shaped cross section.

24. Sensor element according to one of the preceding claims, - in, The main part consists of a (linear) thermal expansion coefficient greater than 5⋅ at an (operating) temperature of 20°C , especially not less than 8⋅ , and / or less than 25⋅ , especially not more than 19⋅ made of materials; and / or - wherein the reference body has a (linear) coefficient of thermal expansion at an (operating) temperature of 20°C less than 11⋅ made of materials; and / or - wherein the filling body consists of a material having a (linear) thermal expansion coefficient at an (operating) temperature of 20°C greater than 5⋅ , especially not less than 8⋅ and / or less than 25⋅ , especially not more than 19⋅ Made of material.

25. Sensor element according to the preceding claim, - in, The thermal expansion coefficient of the main part is not less than the thermal expansion coefficient of the reference body, in particular such that the thermal expansion coefficient of the main part is greater than the thermal expansion coefficient of the reference body at an operating temperature of 20°C by more than 1⋅ , especially not less than 5⋅ ; and / or - wherein the thermal expansion coefficient of the main part is not less than the thermal expansion coefficient of the filling body, in particular such that the thermal expansion coefficient of the main part is greater than 1⋅ of the thermal expansion coefficient of the reference body at an operating temperature of 20°C , especially not less than 5⋅ ; and / or - wherein the coefficient of thermal expansion of the reference body is not greater than the coefficient of thermal expansion of the filling body, in particular such that the coefficient of thermal expansion of the reference body is at least 1⋅ less than the coefficient of thermal expansion of the filling body .

26. Sensor element according to one of the preceding claims, - in, The main part is in particular made completely of metal, in particular (rustproof) stainless steel (W No. 1.4404); and / or - in, The reference body is in particular made completely of metal, in particular a nickel-based alloy (W No. 2.4475); and / or - wherein the filling body consists at least partially, in particular completely, of glass, in particular of molten gas; and / or - wherein the sensor cavity is hermetically sealed; and / or - wherein the main part and the filling body are connected to each other in a force-fitting manner at least at an (operating) temperature of less than 400° C., and / or - wherein the filling body and the reference body are connected to one another in a force-fitting manner at least at an (operating) temperature of less than 400° C.

27. The sensor element according to one of the preceding claims, wherein The sensor chamber is filled with an (inert) gas, in particular nitrogen and / or a noble gas.

28. The sensor element according to one of claims 1 to 26, wherein The sensor cavity is evacuated.

29. The sensor element according to one of the preceding claims, further comprising: A (first) connecting line, which is electrically connected to the reference body, in particular electrically conductively connected to the reference body.

30. The sensor element according to one of the preceding claims, further comprising: A (second) connecting line, which is electrically connected to the main component, in particular electrically conductively connected to the main component.

31. A measuring system for measuring at least one measured variable, in particular a flow parameter or a material parameter, of a fluid measured medium, in particular a gas and / or a liquid, which is in particular guided in a pipeline and / or at least temporarily has a (measured medium) temperature of more than 100° C. and / or acts on the deformable body (of the sensor element) with a pressure difference of more than 10 bar, comprising: Sensor element according to one of the preceding claims and (measurement) electronics electrically connected thereto.

32. The measuring system according to the preceding claim, - wherein the sensor element is designed to respond to a pressure difference of 1 bar acting on the deformable body in a (main) measuring direction (of the sensor element) with a change ΔC1 of the capacitance C1 of not less than 10 fF and / or not more than 1 pF; and / or - in, By means of the deformation body, in particular by means of the deformation body and the main part, a reference potential is provided for at least one (signal) voltage to be processed by means of the measuring electronics, in particular zero, or a ground (GND) of the measuring electronics is formed.

33. Use of a measuring system according to one of the preceding claims for measuring flow parameters, in particular flow velocity and / or volume flow rate and / or mass flow rate, of a fluid measuring medium, in particular steam, flowing in a pipeline, the fluid measuring medium acting on the deformable body (of the sensor element) at a (measuring medium) temperature of greater than 100°C and / or with a pressure difference of greater than 10 bar.

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