Sensorelement

Abstract

The sensor element comprises a base body (11) with a (base body) cavity (11*) having an open first end and a second end, a deformation body (12) made of an electrically conductive material, a sleeve-shaped reference electrode (13) made of an electrically conductive material with a (reference electrode) cavity (13*) having an open first end and a second end, and a filler body (14) made of an electrically non-conductive (insulating) material with a (filler) cavity (14*) having an open first end and a second end. The filler body (14) together with the reference electrode (13) (embedded therein) are arranged within the base body cavity (11*).In addition, the deformation body (12) and the base body (11) are mechanically coupled to form a sensor cavity (1*) in such a way that an (elongated) sensor electrode of the deformation body is arranged partially within the reference electrode cavity, forming an (annular) gap (1') between the sensor electrode and the reference electrode (13), and that the base body (11) and deformation body (12) are connected to each other to form an electrically conductive connection. The deformation body (12) is also configured to execute oscillations about a static rest position in such a way that the sensor electrode executes (cantilever) oscillations that deform the (annular) gap (1') and thus change a (sensor) capacitance C1 formed between the deformation body and the reference electrode (a capacitor formed by the deformation body, the filler body, and the reference electrode).

Description

[0001] The invention relates to a (capacitive) sensor element, in particular a sensor element for (capacitive) detecting pressure fluctuations in a Kármán vortex street formed in a flowing fluid and / or a sensor element which is designed to be contacted by a flowing fluid, as well as a measuring system formed by means of such a sensor element for measuring at least one measured variable of a fluid medium.

[0002] In process measurement and automation technology, measuring systems designed as vortex flow meters are often used to measure flow velocities of fluid media or (measurement) fluids flowing in pipelines, in particular fast-flowing and / or hot gases (> 100°C), e.g. steam, and / or fluid flows with a high Reynolds number (Re > 10000) and / or high static pressures (> 10 bar), or of volume or mass flow rates corresponding to a particular flow velocity. Examples of such measuring systems are known from, among others, US-B 69 10 387, US-B 69 38 496, US-B 97 19 819, US-B 1 08 45 222 or US-B 1 09 48 321 and are also offered by the applicant itself, for example under the product designation “PROWIRL D 200”, “PROWIRL F 200”, “PROWIRL O 200”, “PROWIRL R 200” (http: / / www.de.endress.com / en / search?filter.text=prowirl).

[0003] The aforementioned measuring systems each comprise a bluff body projecting into the lumen of the respective pipeline, for example, a system component of a heat supply network or a turbine circuit, or into a lumen of a measuring tube inserted in the same pipeline, and thus against which the (measured) fluid flows, for generating vortices arranged in a so-called Kärmän vortex street within the partial volume of the fluid flow flowing immediately downstream of the bluff body. The vortices are thereby generated at a flow velocity-dependent separation rate (1 / f vtx) is generated at the bluff body. Furthermore, the measuring systems have a (vortex) sensor element that projects into the flow downstream of the bluff body in the flow direction of the measuring system, namely in the area of ​​the aforementioned Kármán vortex street. This sensor element serves to detect pressure fluctuations in the Kármán vortex street formed in the flowing fluid and to convert them into a sensor signal representing the pressure fluctuations, namely to deliver a signal - for example, an electrical or capacitive-electrical signal - that corresponds to a pressure prevailing within the fluid, which is subject to periodic fluctuations due to counter-rotating vortices downstream of the bluff body, or that has a signal frequency corresponding to the shedding rate of the vortices (~ f vtx ).

[0004] The aforementioned sensor element comprises a (sleeve-shaped and monolithic) base body made of a metal, with a (base body) cavity having a substantially circular open first end and a substantially circular open second end, a deformation body made of a metal, two identical (half-)shell-shaped reference electrodes each made of a metal and a sleeve-shaped filler body made of electrically non-conductive (insulating) material with a (filler body) cavity having a substantially circular open first end and a substantially circular open second end.The aforementioned deformation body comprises a substantially disc-shaped membrane segment, a substantially annular edge segment enclosing the membrane segment forming a (deformation body) cavity having a substantially circular open first end and a closed second end, a sensor flag (“paddle”) arranged on a first (membrane segment) surface of the membrane segment, for example plate-shaped and / or wedge-shaped, and a second (membrane segment) surface of the membrane segment opposite the first (membrane segment) surface, for example rod-shaped and / or sleeve-shaped, (elongated) sensor electrode.The membrane segment is typically shaped such that a (membrane segment) thickness, measured as a minimum thickness of the membrane segment, is much smaller than a (membrane segment) diameter, measured as a largest diameter of the smaller of the aforementioned membrane segment surfaces. The sensor element is in particular designed to be inserted into a wall opening in the wall of the aforementioned tube and to be firmly connected to the wall via an edge segment in such a way that the first membrane segment surface carrying the sensor flag faces the lumen of the tube carrying the (measuring) fluid, and thus the sensor flag projects into the same lumen. The edge segment, in turn, can be designed, among other things, to be connected to a holder for the deformation body orof the sensor element thus formed on the wall serving to enclose the wall opening in a hermetically sealed manner, for example by means of a material bond, in such a way that the membrane segment together with the edge segment covers or hermetically seals the wall opening.

[0005] The two reference electrodes of the respective sensor element are embedded opposite one another and spaced apart from one another in the filler body such that the concave (reference electrode) surfaces of the reference electrodes face one another to form a reference electrode cavity enclosed by them or the exposed regions of the filler body located between the reference electrodes, and at least one first (reference electrode) sub-segment of each of the reference electrodes is contacted by the filler body to form a material bond, and at least one respective second (reference electrode) sub-segment of each of the reference electrodes adjacent to the same first reference electrode sub-segment is not contacted by the filler body.

[0006] The filler body is arranged together with the reference electrodes (embedded therein) within the base body cavity in such a way that the first ends of the filler body and the reference electrodes face the first end of the base body and that a (base body) surface of the base body facing the lumen of the base body cavity and a (filler body) surface of the filler body facing the same base body surface contact each other (forming a frictional connection and / or a form fit and / or a material connection) in such a way that the reference electrodes and the base body are mechanically coupled to each other via the filler body, yet are each galvanically separated or electrically insulated from each other.The deformation body and the base body are also mechanically coupled to one another to form a sensor cavity (involving both a partial area of ​​the deformation body cavity not occupied by the base body and a partial area of ​​the base body cavity not occupied by the filler body or the reference electrodes as well as the aforementioned reference electrode cavity), in such a way that the sensor electrode (of the deformation body) is arranged proportionately within the aforementioned reference electrode cavity to form a circumferential (annular) gap between the sensor electrode and the reference electrodes or exposed areas of the filler body located therebetween, and that a first (base body) partial segment of the base body encompassing the first end of the base body cavity and the edge segment (of the deformation body) are connected to one another to form an (electrically conductive) hermetically sealed connection.The deformation body and the reference electrodes are also designed and arranged in such a way that the aforementioned concave (reference electrode) surfaces and a substantially circular-cylindrical, convex (sensor electrode) surface of the sensor electrode (of the deformation body) do not contact each other or that the reference electrodes and sensor electrode are kept galvanically separated from each other.

[0007] To detect pressure fluctuations in the aforementioned Kármán vortex street, the deformation body of the respective sensor element is specifically designed to perform forced oscillations around a static rest position by (alternating) forces acting on the respective sensor vane, such that the sensor electrode executes (cantilever) oscillations or corresponding pendulum movements that deform the (annular) gap. These (cantilever) oscillations, in turn, lead to temporal changes in the (sensor) capacitances established between the deformation body and the reference electrodes of two (measuring) capacitors formed by the deformation body, the filler body, and the reference electrodes, corresponding to the pressure fluctuations, which can be evaluated in the form of a (capacitive) measurement signal.

[0008] The sensor element is further electrically connected, on a side facing away from the fluid-carrying lumen, to (measuring system) electronics - typically encapsulated in a pressure- and impact-resistant manner, and possibly also hermetically sealed to the outside. (Measuring system) electronics of industrial-grade measuring systems of the type in question usually have a corresponding digital measuring circuit electrically connected to the respective sensor element via connecting cables, possibly with the interposition of electrical barriers and / or galvanic isolation points or feedthroughs, for processing the at least one sensor signal generated by the transducer element and for generating digital measured values ​​for the respective measured variable to be recorded, namely the flow velocity, the volume flow rate and / or the mass flow rate. The (measuring system) electronics of industrial-grade orEstablished measurement systems in industrial measurement technology also usually provide external interfaces compliant with an industry standard, such as DIN IEC 60381-1, for communication with higher-level measurement and / or control systems, such as those formed by programmable logic controllers (PLCs). Such an external interface can, for example, be designed as a two-wire connection that can be integrated into a current loop and / or be compatible with established industrial fieldbuses.

[0009] A disadvantage of measuring systems of the aforementioned type is, among other things, the high technical complexity involved in manufacturing the measuring capacitors used to generate the measurement signal, not least the comparatively complex production of the filler body within the base body, along with the precise positioning and orientation of each of the two reference electrodes. A further disadvantage of such measuring systems is the high technical complexity involved in electrically connecting the sensor element to the respective (measurement system) electronics, not least the necessary two-wire cabling.

[0010] Based on this, it is an object of the invention to provide a (capacitive) sensor element with high measuring sensitivity, particularly suitable for detecting pressure fluctuations in a Kármán vortex street, which (while still maintaining high pressure and temperature resistance) has a structure that is easier to manufacture compared to conventional sensor elements of the type in question. To solve the problem, the invention consists in a (capacitive)

[0011] Sensor element - for example, a sensor element for (capacitive) detecting pressure fluctuations in a Kármán vortex street formed in a flowing fluid and / or a sensor element designed to be contacted by a flowing fluid - which sensor element comprises: • a base body, for example a sleeve-shaped and / or monolithic one, for example made of an electrically conductive material and / or a metal, with a (base body) cavity having a, for example circular, open first end and a, for example circular and / or open, second end; • a deformation body made of an electrically conductive material, for example, having an electrical conductivity of more than 10 at an (operating) temperature of 20°C 5 S / m material, for example a metal, with a (disc-shaped) membrane segment, with a membrane segment, for example a hollow cylindrical or annular edge segment, which encloses the membrane segment to form a (deformation body) cavity having a, for example, circular, open first end and a closed second end, with a sensor flag arranged on a first surface of the membrane segment, for example a plate-shaped and / or wedge-shaped one, for example at least partially planar and / or at least partially (convex) curved one, and with a second (membrane segment) surface of the membrane segment, for example rod-shaped and / or sleeve-shaped, (elongated) sensor electrode arranged on a second (membrane segment) surface of the membrane segment opposite the first (membrane segment) surface; • a, for example, single, sleeve-shaped, for example monolithic and / or non-hollow cylindrical, reference electrode made of an electrically conductive material, for example having an electrical conductivity of more than 10 at an (operating) temperature of 20°C 5S / m material, for example a metal, with a (reference electrode) cavity having an, for example non-circular, open first end and a, for example non-circular and / or open, second end; • and a, for example, sleeve-shaped and / or monolithic, filler made of an electrically non-conductive material, for example having an electrical conductivity of less than 10 at an (operating) temperature of 20°C -8S / m, (insulating) material, for example a glass, a plastic or a ceramic, with a (filler) cavity having, for example, a circular, open first end and a, for example, circular and / or open, second end; wherein the reference electrode is partially embedded in the filler such that at least a first (reference electrode) sub-segment of the reference electrode is enclosed by the filler, for example forming a frictional connection and / or a positive connection and / or a material connection, for example at least a second (reference electrode) sub-segment of the reference electrode adjacent to the same first reference electrode sub-segment and enclosing the first end of the (reference electrode) cavity is not enclosed by the filler; and wherein the filler body is arranged together with the reference electrode (embedded therein) within the base body cavity, such that that the first ends of the filler body and the reference electrode face the first end of the base body, that a (base body) surface of the base body facing the lumen of the base body cavity and a (filler) surface of the filler facing the same base body surface contact each other, for example by forming a force fit and / or a form fit and / or a material fit and that the reference electrode and the base body are mechanically coupled to one another via a filler body, but are nevertheless galvanically separated from one another, for example electrically insulated, for example in such a way that a minimum electrical resistance between the reference electrode and the base body at an (operating) temperature of 20°C is not less than 10 MΩ, for example greater than 50 MΩ; wherein the deformation body and the base body are mechanically coupled to one another to form a sensor cavity (involving both a partial area of ​​the deformation body cavity not occupied by the base body and a partial area of ​​the base body cavity not occupied by the filler body or the reference electrode as well as the reference electrode cavity), such that that the sensor electrode (of the deformation body) is arranged proportionately within the reference electrode cavity, forming, for example, a circumferential (annular) gap between the sensor electrode and the reference electrode and that a first (base body) sub-segment of the base body, which comprises the first end of the base body cavity, and the edge segment of the deformation body are connected to one another to form an electrically conductive, for example hermetically sealed, connection, for example in a materially bonded and / or positively bonded and / or non-positively bonded manner; wherein the deformation body and the reference electrode are arranged such that a (circular) cylindrical, concave (reference electrode) surface of the reference electrode facing the reference electrode cavity (the lumen) and a (sensor electrode) surface of the sensor electrode (of the deformation body) facing the same (reference electrode) surface, for example only partially (circular) cylindrical, do not contact each other, for example in such a way that the reference electrode and the sensor electrode are kept galvanically separated from each other; and wherein the deformation body is configured to execute oscillations around a static rest position, for example, forced by (alternating) forces acting on the deformation body, in such a way that the sensor electrode executes (cantilever) oscillations which deform the (annular) gap and thus change a (sensor) capacitance C1 (of a capacitor formed by the deformation body, the filler body and the reference electrode) formed between the deformation body and the reference electrode, for example, which is not less than 5 pF and / or not more than 100 pF when the deformation body is in a static rest position.

[0012] Furthermore, the invention consists in a measuring system for measuring at least one measured variable, for example a flow parameter or a material parameter, of a fluid measuring substance, for example a gas and / or a liquid, which is guided, for example, in a pipeline and / or at least temporarily has a (measured substance) temperature of more than 100°C and / or acts on the deformation body (of the sensor element) with a pressure difference of more than 10 bar, which measuring system comprises such a sensor element and (measurement system) electronics electrically connected thereto.

[0013] Furthermore, the invention also consists in using such a measuring system for measuring a flow parameter - for example a flow velocity and / or a volume flow rate and / or a mass flow rate - of a fluid medium, for example a steam, flowing in a pipeline, for example at a (measured medium) temperature of more than 100°C and / or with a pressure difference of more than 10 bar acting on the deformation body (of the sensor element).

[0014] According to a first embodiment of the sensor element of the invention, it is further provided that the second end of the (reference electrode) cavity (13*) is closed, for example by means of a plate-shaped cover segment of the reference electrode and / or hermetically.

[0015] According to a second embodiment of the sensor element of the invention, it is further provided that the second end of the (reference electrode) cavity (13*) is open.

[0016] According to a third embodiment of the sensor element of the invention, it is further provided that the (annular) gap (between reference electrode and sensor electrode) is not rotationally symmetrical with respect to an imaginary (sensor electrode) longitudinal axis corresponding to a main axis of inertia of the sensor electrode and / or is not rotationally symmetrical with respect to an imaginary (reference electrode) longitudinal axis corresponding to a main axis of inertia of the reference electrode, at least when the deformation body is in a static rest position.

[0017] According to a fourth embodiment of the sensor element of the invention, it is further provided that the reference electrode is not rotationally symmetrical with respect to the imaginary (reference electrode) longitudinal axis, for example, it is not hollow-cylindrical.

[0018] According to a fifth embodiment of the sensor element of the invention, it is further provided that the sensor electrode is not rotationally symmetrical with respect to the imaginary (sensor electrode) longitudinal axis, for example, it is not circularly cylindrical.

[0019] According to a sixth embodiment of the sensor element of the invention, it is further provided that the sensor electrode and reference electrode are arranged non-coaxially to each other, at least in sections.

[0020] According to a seventh embodiment of the sensor element of the invention, it is further provided that the (annular) gap (1') is kept free of solids.

[0021] According to an eighth embodiment of the sensor element of the invention, it is further provided that no further components of the sensor element are positioned within the (annular) gap (1').

[0022] According to a ninth embodiment of the sensor element of the invention, it is further provided that a (maximum) relative permittivity established within the (annular) gap is not greater than 3, for example, namely less than 1.5.

[0023] According to a tenth embodiment of the sensor element of the invention, it is further provided that the deformation body is designed to be contacted by a fluid, for example a liquid and / or a gas or another fluid, which is flowing and / or at least temporarily has a (fluid) temperature of more than 100°C.

[0024] According to an eleventh embodiment of the sensor element of the invention, it is further provided that the deformation body is designed to be surrounded by a flowing fluid, for example a liquid and / or a gas, formed, for example, into a Kármán vortex street, and, for example, to be elastically deformed by (alternating) forces exerted thereon by the fluid.

[0025] According to a twelfth embodiment of the sensor element of the invention, it is further provided that the deformation body is configured to convert (alternating) forces acting on the sensor vane, for example exerted by a fluid flowing around it and / or introduced via the first and second sensor vane surfaces, into (cantilever) vibrations of the sensor electrode deforming the (sensor) cavity or the (annular) gap.

[0026] According to a thirteenth embodiment of the sensor element of the invention, it is further provided that the sensor vane is configured to convert (alternating) forces exerted transversely to the (main) flow direction by a fluid flowing in a (main) flow direction, for example due to pressure fluctuations within a Kármán vortex street formed in the flowing fluid, into (cantilever) oscillations of the sensor electrode deforming the (sensor) cavity or the (annular) gap in an oscillation direction pointing, for example, transversely to the (main) flow direction and / or in the direction of a (main) measuring direction of the sensor element.

[0027] According to a fourteenth embodiment of the sensor element of the invention, it is further provided that the sensor flag has a first sensor flag surface, for example, which is at least partially flat, and a second sensor flag surface opposite the first sensor flag surface, for example, which is of the same shape and / or (plane-)parallel to the first sensor flag surface and / or at least partially flat. Further developing this embodiment of the invention, the first and second sensor flag surfaces are further configured to be contacted by a, for example, flowing, fluid, for example a liquid and / or a gas, for example in such a way that (alternating) forces generated by the fluid, which cause (cantilever) oscillations of the sensor electrode to deform the (deformation body) cavity or the (annular) gap, are introduced into the deformation body via the first and second sensor flag surfaces.

[0028] According to a fifteenth embodiment of the sensor element of the invention, it is further provided that the deformation body or the sensor vane is configured to convert (alternating) forces exerted thereon in a (main) measuring direction (of the sensor element) into (cantilever) oscillations of the sensor electrode that deform the (deformation body) cavity or the gap. Further developing this embodiment of the invention, it is further provided that a smallest width of the gap is opposite or measurable to a largest width of the gap. Alternatively or additionally, the smallest width of the gap can be located or measurable in the (main) measuring direction and / or the largest width of the gap can be located or measurable in the (main) measuring direction.

[0029] According to a sixteenth embodiment of the sensor element of the invention, it is further provided that a (measuring) capacitor with a (sensor) capacitance C1 co-determined by the (annular) gap is formed by means of the deformation body, the filler body and the reference electrode, for example in such a way that the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX of more than 1 pF / mm in a (main) measuring direction or is set up to react to a maximum (deflection) movement ΔX of 1 µm of the sensor electrode in a (main) measuring direction with a change ΔC1 of the capacitance C1 of more than 1 fF.Developing this embodiment of the invention further, it is further provided that the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX in a (main) measuring direction (of the sensor element), for example, more than 1 pF / mm and / or the greatest, such that the (measuring) capacitor is set up to react to a maximum (deflection) movement ΔX of the sensor electrode in a (main) measuring direction, for example, amounting to 1 µm, with a change ΔC1 in the capacitance C1, for example, amounting to more than 1 fF.In addition, the (measuring) capacitor can advantageously have a transverse sensitivity ΔC1 / ΔY in a direction deviating from the (main) measuring direction, for example by not less than 50% of the (measuring) sensitivity ΔC1 / ΔX, for example in such a way that the transverse sensitivity ΔC1 / ΔY is smaller than the (measuring) sensitivity ΔC1 / ΔX and / or that the (measuring) capacitor is designed to react to a maximum (deflection) movement ΔZ of the sensor electrode in at least one, for example each, direction deviating from the (main) measuring direction with a change ΔC1' of the capacitance C1, which is smaller than the change ΔC1 (of the capacitance C1) with which the (measuring) capacitor reacts to a value equal to large (deflection) movement ΔX of the sensor electrode in the (main) measuring direction.

[0030] According to a seventeenth embodiment of the sensor element of the invention, it is further provided that when the deformation body is in a static rest position, the sensor electrode and the reference electrode are arranged coaxially only in sections, for example, forming a (measuring) capacitor.

[0031] According to an eighteenth embodiment of the sensor element of the invention, it is further provided that a maximum distance between the sensor electrode and the reference electrode 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.

[0032] According to a nineteenth embodiment of the sensor element of the invention, it is further provided that a smallest 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.

[0033] According to a twentieth embodiment of the sensor element of the invention, it is further provided that a 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.

[0034] According to a twenty-first embodiment of the sensor element of the invention, it is further provided that a largest width of the (annular) gap (1') is more than 0.05 mm, for example more than 0.1 mm, larger than a smallest width of the (annular) gap (1').

[0035] According to a twenty-second embodiment of the sensor element of the invention, it is further provided that the sensor electrode has a (sensor electrode) mass which is less than 10 g.

[0036] According to a twenty-third embodiment of the sensor element of the invention, it is further provided that the deformation body has a minimum wall thickness which is not less than 0.4 mm and / or not greater than 2 mm.

[0037] According to a twenty-fourth embodiment of the sensor element of the invention, it is further provided that the sensor flag has a (sensor flag) mass which is less than 50 g and / or not less than 4 g, for example such that the (sensor flag) mass is equal to a (sensor electrode) mass of the sensor electrode.

[0038] According to a twenty-fifth embodiment of the sensor element of the invention, it is further provided that the sensor electrode has a (sensor electrode) length which is less than 50 mm and / or greater than 5 mm.

[0039] According to a twenty-sixth embodiment of the sensor element of the invention, it is further provided that the base body has a (base body) length which is greater than 5 mm and / or less than 100 mm, for example not greater than 50 mm.

[0040] According to a twenty-seventh embodiment of the sensor element of the invention, it is further provided that the filler body has a (filler body) length which is greater than 5 mm and / or less than 100 mm, for example not greater than 50 mm.

[0041] According to a twenty-eighth embodiment of the sensor element of the invention, it is further provided that a minimum distance between the sensor electrode and the reference electrode 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. Further developing this embodiment of the invention, it is further provided that the filler body length is smaller than the base body length and / or that the filler body length is smaller than the reference electrode length and / or that the base body length is greater than the reference electrode length.

[0042] According to a twenty-ninth embodiment of the sensor element of the invention, it is further provided that the filler body is arranged within the base body cavity in such a way that a partial area of ​​the base body cavity surrounded by the first base body sub-segment (forming the first end of the base body cavity) is not filled or occupied by the filler body.

[0043] According to a thirtieth embodiment of the sensor element of the invention, it is further provided that the second (sensor electrode) sub-segment (of the sensor electrode), for example to increase a mutual (frequency) distance between natural or resonant frequencies of different oscillation modes of the sensor element and / or to increase a (measurement) sensitivity ΔC1 / ΔX of a capacitor C1 formed by means of the deformation body, the filler body and the reference electrode relative to a transverse sensitivity ΔC1 / ΔY of the same capacitor C1, is not rotationally symmetrical with respect to an imaginary longitudinal axis of the same (sensor electrode) sub-segment, for example in such a way that the second (sensor electrode) sub-segment has a D-shaped and / or T-shaped and / or oval-shaped cross-section.

[0044] According to a thirty-first embodiment of the sensor element of the invention, it is further provided that the first (reference electrode) sub-segment (of the reference electrode) has a (sub-segment) length which is greater than 10 mm and / or less than 100 mm.

[0045] According to a thirty-second embodiment of the sensor element of the invention, it is further provided that at least one second (reference electrode) sub-segment (13b) of the reference electrode (13) adjacent to the same first reference electrode sub-segment is not covered by the filler body (14).Developing this embodiment of the invention further, it is further provided that the reference electrode has a (reference electrode) length that is greater than 10 mm and / or less than 100 mm, for example such that a (partial segment) length of the second reference electrode sub-segment is less than 50 mm and / or more than 10 mm and / or less than 50% of the (reference electrode) length and / or more than 10% of the (reference electrode) length, and / or that the reference electrode is (only) partially (circular) cylindrical, for example such that a smallest (cylinder) diameter of the second reference electrode sub-segment is greater than 3 mm and / or that a smallest (cylinder) diameter of the first reference electrode sub-segment is greater than a smallest (cylinder) diameter of the second reference electrode sub-segment.Alternatively or additionally, the second (reference electrode) sub-segment (of the reference electrode) can have a (sub-segment) length that is advantageously greater than 10 mm and / or less than 100 mm, and / or the reference electrode can advantageously be embedded in the filler body in such a way that a third (reference electrode) sub-segment of the reference electrode, which is adjacent to the first reference electrode sub-segment but is remote from the second (reference electrode) sub-segment and is, for example, sleeve-shaped, is not enveloped by the filler body.

[0046] According to a thirty-third embodiment of the sensor element of the invention, it is further provided that the base body consists of a material of which a (linear) thermal expansion coefficient at an (operating) temperature of 20°C is more than 5·10 -6 K -1 , for example not less than more than 8·10 -6 K -1 , and / or less than 25·10 -6 K -1, for example, not more than 19·10 -6 K -1 , amounts.

[0047] According to a thirty-fourth embodiment of the sensor element of the invention, it is further provided that the reference electrode consists of a material having a (linear) thermal expansion coefficient at an (operating) temperature of 20°C of less than 11 10 -6 K -1 amounts.

[0048] According to a thirty-fifth embodiment of the sensor element of the invention, it is further provided that the filler body consists of a material of which a (linear) thermal expansion coefficient at an (operating) temperature of 20°C is more than 5·10 -6 K -1 , for example not less than 8·10 -6 K -1 , and / or less than 25·10 -6 K -1 , for example, not more than 19·10 -6 K -1, is. Further developing this embodiment of the invention, it is further provided that the thermal expansion coefficient (of the material) of the base body is not smaller than the thermal expansion coefficient (of the material) of the reference electrode, for example such that the thermal expansion coefficient (of the material) of the base body at an (operating) temperature of 20°C is more than 1·10 -6 K -1 , for example by no less than 5·10 -6 K -1 , is greater than the thermal expansion coefficient (of the material) of the reference electrode, and / or that the thermal expansion coefficient (of the material) of the base body is not smaller than the thermal expansion coefficient (of the material) of the filler body, for example such that the thermal expansion coefficient (of the material) of the base body at an (operating) temperature of 20°C is more than 1·10 -6 K -1 , for example by no less than 5·10 -6 K -1, is greater than the thermal expansion coefficient (of the material) of the filler, and / or that the thermal expansion coefficient (of the material) of the reference electrode is not greater than the thermal expansion coefficient (of the material) of the filler, for example such that the thermal expansion coefficient (of the material) of the reference electrode is less than 1·10 -6 K -1 is smaller than the thermal expansion coefficient (of the material) of the filler.

[0049] According to a thirty-sixth embodiment of the sensor element of the invention, it is further provided that the base body, for example completely, consists of a metal, for example a (rust-proof) stainless steel (WNo. 1.4404).

[0050] According to a thirty-seventh embodiment of the sensor element of the invention, it is further provided that the reference electrode consists, for example entirely, of a metal, for example a nickel-based alloy (WNo. 2.4475).

[0051] According to a thirty-eighth embodiment of the sensor element of the invention, it is further provided that the filling body consists at least partially, for example completely, of a glass, for example a melting gas.

[0052] According to a thirty-ninth embodiment of the sensor element of the invention, it is further provided that the sensor cavity is hermetically sealed.

[0053] According to a fortieth embodiment of the sensor element of the invention, it is further provided that the base body and the filling body are connected to one another in a force-locking manner at least at an (operating) temperature of less than 400°C.

[0054] According to a forty-first embodiment of the sensor element of the invention, it is further provided that the filler body and the reference electrode are connected to one another in a force-locking manner at least at an (operating) temperature of less than 400°C.

[0055] According to a forty-second embodiment of the sensor element of the invention, it is further provided that the sensor cavity is filled with an (inert) gas, for example nitrogen and / or a noble gas.

[0056] According to an embodiment of the measuring system of the invention, it is further provided that the sensor cavity is evacuated.

[0057] According to a first development of the invention, the development further comprises: a (first) connecting line electrically connected to the reference electrode, for example electrically conductively connected thereto.

[0058] According to a second development of the invention, the development further comprises: a (second) connecting line electrically connected to the base body, for example electrically conductively connected thereto.

[0059] According to a first embodiment of the second development of the invention, the sensor element is further configured to react to a pressure difference of 1 bar acting on the deformation 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.

[0060] According to a second embodiment of the second development of the invention, it is further provided that by means of the deformation body, for example by means of the deformation body and the base body, a reference potential, for example zero, is provided for at least one (signal) voltage to be processed by the measuring electronics or a ground (GND) of the measuring electronics is formed.

[0061] A basic idea of ​​the invention is, among other things, to provide a (capacitive) sensor element with high measurement sensitivity and high pressure and / or temperature resistance by detecting deformation movements of the deformable body relative to a sleeve-shaped (single) reference electrode placed within the base body and converting these into a change in the (sensor) capacitance or a corresponding (capacitive) electrical measurement signal. The sensor element according to the invention has a mechanical and electrical structure that is comparatively simple to manufacture and also very robust (while still maintaining high measurement accuracy and good resolution of vortex-based oscillatory movements).

[0062] The invention and advantageous embodiments thereof are explained in more detail below using exemplary embodiments illustrated in the figures of the drawing. Identical or equivalent or functioning parts are provided with the same reference numerals in all figures; where clarity requires it or it otherwise seems appropriate, previously mentioned reference numerals are omitted in subsequent figures. Further advantageous embodiments or developments, in particular combinations of partial aspects of the invention initially explained only individually, will become apparent from the figures of the drawing and / or from the claims themselves. In detail: Fig. 1a, b show various views of an embodiment of a (capacitive) sensor element according to the invention; Fig. 2a, b the sensor element according to Fig. 1a and 1b in further different side views; Fig. 3 the sensor element according to Fig. 1a and 1b in a sectioned side view; Fig. 4a, b, c show various views of a further embodiment of a (capacitive) sensor element according to the invention; and Fig. 5a, b schematically show in different views an embodiment of a measuring system formed by means of a sensor element according to the invention.

[0063] In the Fig. 1a, Fig. 1b, Fig. 2a and Fig. Figure 2b schematically shows various views of an embodiment of a (capacitive) sensor element according to the invention. The sensor element serves, in particular, to detect pressure fluctuations in a flowing medium or in a Kármán vortex street formed in a flowing fluid and to convert them into a (capacitive) sensor signal. Advantageously, the sensor element, as also shown in Fig. 5b, for example, can also be designed as a component or part of a measuring system (MS) for measuring at least one flow parameter, which may also be variable over time, such as a flow velocity v and / or a volume flow V', of a (measurement) fluid flowing in a pipeline, for example a hot gas or a liquid, in particular one which at least temporarily has a temperature of more than 100°C and / or is at least temporarily under a high pressure, in particular of more than 10 bar.

[0064] The sensor element 1 comprises, as in Fig. 1b and Fig. 3 respectively shown or from a summary of the Fig. 1a, Fig. 1b, Fig. 2a, Fig. 2b and Fig. 3, a (sleeve-shaped), in particular at least partially hollow-cylindrical and / or monolithic, base body 11 with a (base body) cavity 11* having, for example, a circular, open first end and a (base body) cavity 11* having, for example, a circular, open second end, a deformation body 12, a sleeve-shaped, for example monolithic, reference electrode 13 with a (reference electrode) cavity 13* having an open first end and an open second end, and a (filling body) cavity 14, for example a sleeve-shaped and / or monolithic, with a (filling body) cavity 14* having, for example, a circular, open first end and a (filling body) cavity 14* having, for example, a circular, open second end. At least the base body 11 and the deformation body 12 can, with regard to their structure, for example, also be similar to a base body orDeformation bodies according to one of the mentioned US-B 69 10 387, US-B 69 38 496, US-B 97 19 819, US-B 1 08 45 222 or US-B 1 09 48 321.

[0065] The deformation body 12 of the sensor element according to the invention has, in particular, a disk-shaped membrane segment 12a, an edge segment 12b, for example a hollow cylindrical or annular one, an (elongated) sensor flag 12c arranged on a first (membrane segment) surface of the membrane segment, for example at least partially flat and / or at least partially (convexly) curved, and an (elongated) sensor electrode 12d arranged on a second (membrane segment) surface of the membrane segment opposite the first membrane segment surface, wherein the edge segment 12b encloses the membrane segment 12a to form a (deformation body) cavity (12*) having, for example, a circular, open first end and a closed second end. The sensor flag 12c has aThe sensor electrode 12d has a (proximal) first (sensor flag) end connected to the first membrane segment surface and a (distal) free second (sensor flag) end (distance therefrom). The sensor electrode 12d has a (proximal) first (sensor electrode) end connected to the membrane segment 12b and a (distal) free second (sensor electrode) end (distance therefrom). The sensor electrode 12d can advantageously be designed to be (circularly) cylindrical at least in sections, for example also in such a way that the sensor electrode 12d is only (circularly) cylindrical in sections and / or, not least for the purpose of saving material or reducing (moving) mass, partially hollow-cylindrical. In addition, the sensor flag 12c can, as is quite common with sensor elements of the type in question or measuring systems formed therewith, be formed, for example, in a plate-shaped and / or wedge-shaped manner and / or the sensor electrode can, for example, be formed in a rod-shaped and / or sleeve-shaped manner.

[0066] According to a further embodiment of the invention, the base body 11 has a (base body) length L11 that is greater than 5 mm (millimeters) and / or less than 100 mm, in particular not greater than 50 mm, and / or the filler body has a (filler body) length L14 that is greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm, and / or the reference electrode 13 has a (reference electrode) length L13 that is greater than 10 mm and / or less than 100 mm. Alternatively or additionally, the filler body length can advantageously also be less than the base body length and / or less than the reference electrode length L13 and / or the base body length can advantageously be less than the reference electrode length.According to a further embodiment of the invention, the reference electrode has a (reference electrode) mass that is less than 10 g (grams), and / or the deformation body 12 has a (deformation body) mass that is not greater than 50 g and / or not less than 4 g.

[0067] The deformation body 12 and the, for example, monolithic, reference electrode 13, and possibly also the, for example, monolithic, base body 11 are preferably made of electrically conductive material, in particular material that is electrically highly conductive or has an electrical conductivity of more than 10 at an (operating) temperature of 20°C. 5 S / m (Siemens per meter), for example a metal, whereas the filler body 14 is made of electrically poorly or non-conductive material, in particular at an (operating) temperature of 20°C an electrical conductivity of less than 10 -8S / m, (insulating) material, for example a glass, a plastic or a ceramic. Advantageously, the base body 11 and the deformation body 12 can, for example, also be made of the same material. In addition, the base body 11 and the deformation body 12 can, for example, also be components of one and the same monolithic molded part, which is, for example, cast or produced by a generative process such as 3D laser melting; However, the base body 11 and the deformation body 12 can also be designed as individual parts that are initially separate from one another or only subsequently joined to one another by a material bond, for example, welded or soldered to one another, and can therefore be made of materials that can be joined to one another by a material bond.According to a further embodiment of the invention, the base body 11 consists of a material having a (linear) thermal expansion coefficient of more than 5 10 at an (operating) temperature of 20°C. -6 K -1 , in particular not less than more than 8·10 -6 K -1 , and / or less than 25·10 -6 K -1 , in particular not more than 19·10 -6 K -1 , and / or the reference electrode 13 is made of a material having a (linear) thermal expansion coefficient at an (operating) temperature of 20°C of less than 11·10 -6 K -1 and / or the filler body 14 is made of a material having a (linear) thermal expansion coefficient at an (operating) temperature of 20°C of more than 5·10 -6 K -1 , in particular not less than 8·10 -6 K -1 , and / or less than 25·10 -6 K -1 , in particular not more than 19·10 -6 K -1, is; this in particular in such a way that the thermal expansion coefficient (of the material) of the base body 11 is not less than the thermal expansion coefficient (of the material) of the reference electrode 13 and / or that the thermal expansion coefficient (of the material) of the base body is not less than the thermal expansion coefficient (of the material) of the filler body 14 and / or that the thermal expansion coefficient (of the material) of the reference electrode is not greater than the thermal expansion coefficient (of the material) of the filler body 14. Advantageously, the materials for the base body 11, reference electrode 13 and filler body 14 can also be selected such that the thermal expansion coefficient (of the material) of the base body at an (operating) temperature of 20°C is more than 1 10 -6 K -1 , in particular by not less than 5·10 -6 K -1, is greater than the thermal expansion coefficient (of the material) of the reference electrode 13, and / or that the thermal expansion coefficient (of the material) of the base body at an (operating) temperature of 20°C is more than 1·10 -6 K -1 , in particular by not less than 5·10 -6 K -1 , is greater than the thermal expansion coefficient (of the material) of the filler body 14 and / or that the thermal expansion coefficient (of the material) of the reference electrode 13 is less than 1·10 -6 K -1is smaller than the thermal expansion coefficient (of the material) of the filler body 14. According to a further embodiment of the invention, the base body 11 consists at least partially, in particular completely, of a metal, for example a (rust-proof) stainless steel (WNo. 1.4404), and / or the reference electrode 13 consists at least partially, in particular completely, of a metal, for example a nickel-based alloy (WNo. 2.4475), and / or the filler body 14 consists at least partially, in particular completely, of a glass, for example a melting gas.

[0068] In the sensor element according to the invention, the reference electrode 13 is at least partially embedded in the filler body 14 in such a way that at least a first (reference electrode) sub-segment 13a of the reference electrode 13 is enveloped by the filler body, in particular by forming a force fit and / or a form fit and / or a material fit; This is also the case, for example, in such a way that at least one (sleeve-shaped) second (reference electrode) sub-segment 13b of the reference electrode, which is adjacent to the same first (reference electrode) sub-segment 13a and then forms or encloses the first end of the reference electrode, is not covered by the filler body 14 and / or that the sensor element is intact at least up to an (operating) temperature of 400°C or that the reference electrode 13 and the filler body 14 are non-positively connected to one another at least at an (operating) temperature of 400°C or less and / or that the reference electrode 13 and the filler body 14 are clamped or pressed against one another.According to a further embodiment of the invention, the reference electrode 13 is further designed and embedded in the filler body 14 such that the first (reference electrode) sub-segment 13a (of the reference electrode) has a (sub-segment) length L13a that is greater than 10 mm and / or less than 100 mm, and / or that the second (reference electrode) sub-segment 13b (of the reference electrode) has a (sub-segment) length L13b that is greater than 10 mm and / or less than 100 mm.Alternatively or additionally, a largest inner diameter d13b of the aforementioned second reference electrode sub-segment 13b can be greater than 3 mm and / or advantageously selected such that the largest inner diameter d13b of the second reference electrode sub-segment 13b is greater than a largest inner diameter d13a of the first reference electrode sub-segment 13a, and / or the reference electrode 13 can also be designed and embedded in the filler body 14 such that the aforementioned (sub-segment) length of the second reference electrode sub-segment is less than 50% of the (reference electrode) length and / or more than 10% of the (reference electrode) length. According to a further embodiment of the invention, the reference electrode 13 is further embedded in the filler body in such a way that a portion adjacent to the first reference electrode sub-segment 13a, but at a distance from the second (reference electrode) sub-segment, then forming the second end of the reference electrode orenclosing (sleeve-shaped) third (reference electrode) sub-segment of the reference electrode (like the aforementioned second reference electrode sub-segment) is not covered by the filler body 14.

[0069] In the sensor element according to the invention, the filling body 14 is arranged together with the reference electrode 13 (embedded therein) within the base body cavity 11*, in such a way that, as in Fig. 1b, Fig. 2b or Fig. 3 and, as can be seen from their combination, a (base body) surface of the base body facing the lumen of the base body cavity 11* and a (filler) surface of the filler facing the same base body surface contact each other (forming a frictional connection and / or a form fit and / or a material connection) and that the reference electrode 13 and base body 11 are mechanically coupled to each other via the filler body 14, but are galvanically separated from each other or electrically insulated from each other; this, for example, also in such a way that a (smallest) electrical resistance R1 between the reference electrode 13 and base body 11 at an (operating) temperature of 20°C is not less than 10 MΩ, in particular.namely greater than 50 MΩ, and / or that the base body 11 and the filler body 14 are non-positively connected to one another at least at an (operating) temperature of 400°C or less and / or that the filler body 14 and the base body 11 are clamped or pressed against one another. According to a further embodiment of the invention, the filler body 14 is further arranged within the base body cavity 11*, not least to protect against mechanical overload or damage, in such a way that a partial area of ​​the base body cavity surrounded by the first base body sub-segment (forming the first end of the base body cavity) is not filled by the filler body 14 or is not occupied by the filler body 14. The base body and the reference electrode can advantageously be joined by means of primary forming to form the filler body within the base body cavity.The filler body can accordingly, for example, be formed directly within the base body by first placing the reference electrode within the base body cavity (corresponding to the installation position and orientation to be achieved) to form an (annular gap-shaped) intermediate space at a distance from the base body, material useful for producing the filler body, for example in the form of granules and / or a melt, is introduced into the intermediate space, and then the filler body is formed directly within the base body cavity by solidification of initially at least partially liquid, for example partially or molten, (filler body) material in the aforementioned intermediate space.

[0070] The deformation body 12 and the base body 11 in the sensor element according to the invention are further mechanically coupled to one another to form a sensor cavity 1* (11*+12*), which includes both a partial area of ​​the deformation body cavity 11* not occupied by the base body and a partial area of ​​the base body cavity 11* which is neither occupied by the filler body 14 nor by the reference electrode 13, but which nevertheless contains the reference electrode cavity 13* itself, in such a way that, as also in Fig. 3, the first ends of the reference electrode and the filler body face the first end of the base body, and that a first (base body) sub-segment of the base body 11, which encompasses the first end of the base body cavity 11*, and the edge segment of the deformation body 12 are connected to one another, forming an electrically conductive, in particular hermetically sealed, connection, in particular by a material fit and / or a form fit and / or a force fit. Furthermore, the deformation body 12 and the base body 11 are connected to one another in such a way that the sensor electrode 12 (of the deformation body), as shown in Fig. 1b, Fig. 2b or Fig. 3 or also readily apparent from their combination, forming a particularly circumferential (annular) gap 1' between the sensor electrode and the reference electrode 13, whereby as a result a (measuring) capacitor of the sensor element is formed, comprising the base body 11, the deformation body 12, the filling body 14 and the reference electrode 13; this, for example, in such a way that the measuring capacitor is designed as an (ideally coaxial) cylindrical capacitor or that the measuring capacitor - as also in the Fig. 1b, Fig. 2b, Fig. 3, Fig. 4a, Fig. 4b, or 4c - is designed as a cylindrical capacitor with a non-coaxial electrode geometry.

[0071] As in Fig. 3 schematically shown or in summary of the Fig. 1b, Fig. 2b and Fig. 3, the deformation body 12 and the reference electrode 13 of the sensor element according to the invention are further arranged such that a (reference electrode) surface of the reference electrode 12 facing the lumen of the reference electrode cavity 12*, in particular a (circular) cylindrical surface, and a (sensor electrode) surface of the sensor electrode 13 facing the same (reference electrode) surface, for example, only partially (circular) cylindrical, do not contact each other; this is particularly also the case in such a way that the reference electrode and the deformation body are galvanically decoupled from each other or galvanically separated from each other. According to a further embodiment of the invention, it is further provided that a (maximum) relative permittivity ε established within the (annular) gap ris not greater than 3 in total, in particular less than 1.5. Alternatively or additionally, no further components of the sensor element are positioned - entirely or partially - within the (annular) gap 1', or the (annular) gap 1' is advantageously kept free of solids, for example in the form of (plastic) foils or flexible (plastic) plates.

[0072] According to a further embodiment of the invention, the sensor cavity 1* is hermetically sealed, for example, in that the reference electrode has a (plate-shaped) cover segment that (tightly) closes the above-described second end of its (reference electrode) cavity 13*. Alternatively or additionally, a hermetically sealed sensor cavity 1* can also be formed by hermetically sealing the second end of the (main body) cavity (13*), for example, by means of a corresponding cover or cap. In the event that the sensor cavity is hermetically sealed, it can also be evacuated (ε r@0Hz = ε r = ε / ε0 = 1) or, for example, filled with an (inert) gas, in particular a noble gas (He, Ar) and / or nitrogen (N).

[0073] The deformation body 12 of the sensor element according to the invention is furthermore particularly intended or configured to execute mechanical oscillations, in particular (mechanical) oscillations forced by (alternating) forces (F) acting on its sensor vane, in order to achieve a static rest position and thereby be partially elastically deformed or moved (in one or more degrees of freedom) relative to a static rest position; this in particular in such a way that the membrane segment (of the deformation body) is elastically deformed or moved relative to a static rest position and / or that the sensor electrode (of the deformation body) can execute or executes (cantilever) oscillations ΔX(t) that deform the (annular) gap 1' and thus change a (sensor) capacitance C1 (of the aforementioned measuring capacitor) that can be measured between the deformation body 12 and the reference electrode 13. The (measuring) capacitor of the sensor element can advantageously be designed orbe dimensioned such that its (sensor) capacitance C1 is, for example, not less than 5 pF and / or not more than 100 pF when the deformation body is in a static rest position. According to a further embodiment of the invention, the membrane segment and the sensor electrode fixed thereto or the deformation body formed thereby are further provided or designed to enable or carry out the aforementioned cantilever oscillations ΔX(t) of the sensor electrode (which deform gap 1' or change capacitance C1) in a predetermined (main) detection or (main) measuring direction (x-direction) of the sensor element.

[0074] To effect the aforementioned vibrations of the deformation body, in particular the cantilever vibrations ΔX(t) of the sensor electrode 12d, the sensor vane 12c (of the deformation body) is further provided or configured, according to a further embodiment of the invention, to be contacted or flowed around by (measuring) fluid during operation of the sensor element or the measuring system formed thereby; this in particular in such a way that the sensor vane is allowed to flow around by flowing (measuring) fluid and / or fluid formed into a Kármán vortex street and / or in such a way that the aforementioned (alternating) forces F(t) (forcing mechanical vibrations of the deformation body) are exerted by the flowing fluid on the sensor vane. According to a further embodiment of the invention, the sensor flag 12c, which is for example plate-shaped and / or wedge-shaped, has a, in particulara first sensor flag surface that is at least partially flat, and a second sensor flag surface that is opposite the first sensor flag surface, in particular that is at least partially flat and / or has the same shape as the first sensor flag surface. The first and second sensor flag surfaces can advantageously be designed and arranged such that at least one surface normal of the first sensor flag surface is aligned with a surface normal of the opposite second sensor flag surface, or that the surface normals of the first and second sensor flag surfaces run parallel to one another, in particular are coincident; this can also be done, for example, in such a way that the aforementioned first and second sensor flag surfaces are at least partially (plane-)parallel and / or at least partially anti-parallel, and / or that the surface normals of the first and / or second sensor flag surfaces correspond to or are aligned with the aforementioned (main) measuring direction (x-direction) of the sensor element.define the same measuring direction.

[0075] As already indicated, in the sensor element according to the invention, a (measuring) capacitor is formed by means of the deformation body 12, the filling body 14 and the reference electrode 13, the (sensor) capacitance C1 of which is co-determined by the (annular) gap or is variable during operation of the measuring system formed by the sensor element (depending on at least one of its measured variables).

[0076] In order to provide a measuring capacitor with the highest possible (measurement) sensitivity to the aforementioned deformations of the deformation body, not least those in the (main) measuring direction of the sensor element, the (annular) gap according to a further embodiment of the invention is not rotationally symmetrical with respect to an imaginary (sensor electrode) longitudinal axis corresponding to a main axis of inertia of the sensor electrode 12d and / or not rotationally symmetrical with respect to an imaginary (reference electrode) longitudinal axis corresponding to a main axis of inertia of the reference electrode, for example also in such a way that the (annular) gap 1' is (only) partially hollow-cylindrical.For this purpose, the deformation body 12 and the reference electrode 13 can also be designed and arranged such that the deformation body 12, in the static rest position, and the reference electrode 13 are arranged coaxially only in sections or not at all. According to a further embodiment of the invention, the (sleeve-shaped) reference electrode 13, as also shown in . Fig. 1b or Fig. 2b, is not hollow-cylindrical in shape at least in sections, for example in such a way that its (open) first end and / or its second end is not circular, for example in an elliptical or oval shape, or in that its lumen is not circular-cylindrical in shape at least in sections. Accordingly, at least the second (reference electrode) sub-segment 13b can advantageously be non-rotationally symmetrical in shape, at least in sections, with respect to an imaginary (sub-segment) longitudinal axis of the same (reference electrode) sub-segment, for example in such a way that the second (reference electrode) sub-segment 13b, in particular in a region forming the first end of the reference electrode, has an oval-shaped cross-section (having at most one axis of symmetry). Alternatively or additionally, the first (reference electrode) sub-segment 13a and / or the optionallyThe third (reference electrode) sub-segment present may not be rotationally symmetrical, for example oval-shaped, at least in sections with respect to a respective imaginary (sub-segment) longitudinal axis, particularly in a region forming the respective second end of the reference electrode. According to a further embodiment of the invention, the sensor electrode 12d, as also shown in FIG. Fig. 4a, Fig. 4b and Fig. 4c respectively or from their combination is readily apparent (for the purpose of forming the annular gap 1' which is not rotationally symmetrical in the manner described above) is at least partially not rotationally symmetrical with respect to the aforementioned (sensor electrode) longitudinal axis; this, for example, in such a way that sensor electrode 12d has cross sections with at most one axis of symmetry and / or that its (free) second end is not circular, for example D- or T-shaped or, as in Fig. 4a and 4b respectively, is oval-shaped.

[0077] According to a further embodiment of the invention, the reference electrode and the deformation body are particularly designed and arranged in such a way that a smallest distance a1 between the sensor electrode 12d and the reference electrode 13 or a smallest width of the gap 1' is greater than 0.01 mm, for example also greater than 0.1 mm, and / or less than 1 mm, for example also less than 0.5 mm, and / or that a distance a2 between the reference electrode 13 and the sensor electrode 12d ora width of the gap 1' that can be measured (diametrically) opposite the smallest width is greater than 0.02 mm, for example also greater than 0.2 mm, and / or smaller than 10 mm, for example also smaller than 5 mm; this, for example, also in such a way that the aforementioned distance a2 is more than 0.01 mm and / or more than 10% of the (smallest) distance a1 greater than the (smallest) distance a1 and / or that the (smallest) distance a1 is measurable or arranged along the aforementioned (main) measuring direction of the sensor element and / or that the distance a2 is measurable or arranged along the same (main) measuring direction.

[0078] According to a further embodiment of the invention, the (measuring) capacitor further has a (measuring) sensitivity ΔC1 / ΔX of more than 1 pF / mm (picofarad per millimeter) in the aforementioned (main) measuring direction of the sensor element, or the (measuring) capacitor is configured to react to a maximum (deflection) movement ΔX of 1 µm (micrometer) of the sensor electrode in the aforementioned (main) measuring direction with a change ΔC1 in the capacitance C1 of more than 1 fF (femtofarad). Advantageously, the (measuring) capacitor or the sensor element formed thereby can further be configured such that the capacitor has a maximum (measuring) sensitivity ΔC1 / ΔX, in particular more than 1 pF / mm, in the aforementioned (main) measuring direction; this in particularin such a way that the (measuring) capacitor reacts to a maximum (deflection) movement ΔX of the sensor electrode of more than 1 µm and / or less than 5 µm in the aforementioned (main) measuring direction with a change ΔC1 in the capacitance C1 of more than 1 fF. Alternatively or additionally, the (measuring) capacitor or the sensor element formed therewith can be further designed such that the (measuring) capacitor has a transverse sensitivity ΔC1 / ΔZ that deviates from the (measuring) sensitivity ΔC1 / ΔX, for example by not less than 50% of the (measuring) sensitivity ΔC1 / ΔX, in a direction deviating from the (main) measuring direction; this in particular also in such a way that the transverse sensitivity ΔC1 / ΔZ, in particular by not less than 50% of the (measurement) sensitivity ΔC1 / ΔX, is smaller than the (measurement) sensitivity ΔC1 / ΔX and / or that the (measurement) capacitor is responsive to a (deflection) movement ΔZ of the deformation body 12, in particular of more than 1 µm, in at least one, in particulareach direction deviating from the (main) measuring direction reacts with a change ΔC1' of the capacitance C1 which is smaller than the change ΔC1 (of the capacitance C1) with which the (measuring) capacitor reacts to a (deflection) movement ΔX of the deformation body 12 in the (main) measuring direction x.

[0079] The sensor element according to the invention can, as already mentioned several times, also be a component of a measuring system used to measure one or more flow parameters of a (measuring) fluid flowing in a pipeline, an embodiment of which is described in Fig. 5a or 5b is shown schematically. The aforementioned pipeline - not shown here - can be designed, for example, as a system component of a heat supply network or a turbine circuit, thus the (measurement) fluid or the medium to be measured can be, for example, steam, in particular saturated steam or superheated steam, or, for example, (cooling) water or a condensate discharged from a steam line. However, the (measurement) fluid can also be, for example, water, a (compressed) natural gas or biogas, or gaseous or liquefied hydrogen, thus the pipeline can, for example, also be a component of a natural gas or biogas plant, a pressurized or liquid hydrogen plant or a gas supply network, etc. According to one embodiment of the measuring system, sensor element 1 is particularly provided ordesigned to detect pressure fluctuations in the (measuring) fluid flowing past the sensor element 1 in a (main) flow direction (of the measuring system MS) and to convert them into a (capacitive) electrical sensor signal s1 corresponding to the same pressure fluctuations.

[0080] As can be seen from the overview of Fig. 5a and Fig. 5b, the measuring system further comprises, in addition to the sensor element, a (measuring system) electronics 2 - for example, housed in a pressure- and / or impact-resistant protective housing 20 - which is connected to the sensor element or communicates with the sensor element 1 during operation of the measuring system. The measuring electronics 2 is particularly designed to process the sensor signal s1, for example, namely the measured values ​​X representing at least one flow parameter, for example the flow velocity v or the volume flow rate V'. M to generate. The measured values ​​X Mcan, for example, be visualized on site and / or transmitted - wired via a connected fieldbus and / or wirelessly via radio - to an electronic data processing system, such as a programmable logic controller (PLC) and / or a process control station. The protective housing 20 for the measuring electronics 2 can, for example, be made of a metal, such as stainless steel or aluminum, and / or by means of a casting process, such as an investment casting or a high-pressure die-casting process (HPDC); but it can also, for example, be formed by means of a plastic molded part produced by an injection molding process. For electrical connection to the aforementioned (measuring system) electronics 2, the sensor element 1, according to a further embodiment, further comprises a (first) connecting line I1 electrically connected to its reference electrode 13, in particular electrically conductively connected thereto.Furthermore, the sensor element can also have, for example, a further (second) connecting line I2, which also serves for the electrical connection to the (measuring system) electronics, which can advantageously be electrically connected to the base body 11 or electrically conductively connected thereto. Alternatively or additionally, a reference potential, for example zero, can be provided by means of the deformation body 12 or by means of the deformation body 12 and the base body 11 for at least one (signal) voltage to be processed by the measuring electronics, or advantageously also a ground (GND) of the measuring electronics 2 can be formed.

[0081] According to a further embodiment of the invention, the measuring system MS further comprises a tube 3 which can be inserted into the course of the aforementioned pipeline and has a lumen 3' which is surrounded by a - for example metallic - wall 3* of the tube and which extends from an inlet end 3+ to an outlet end 3# and which is designed to guide the fluid flowing in the pipeline. Fig. In the embodiment shown in Figures 2 and 5a, a flange is provided at the inlet end 3+ and at the outlet end 3#, respectively, to establish a leak-free flange connection with a corresponding flange on a respective inlet-side or outlet-side line segment of the pipeline. Furthermore, the pipe 3 is essentially straight, for example, designed as a hollow cylinder with a circular cross-section, such that the pipe 3 has an imaginary straight longitudinal axis L3 imaginarily connecting the inlet end 3+ and the outlet end 3#. The sensor element 1 is accessible from the outside through an opening 3" ( Fig. 4c) into the lumen of the tube 3 and fixed in the area of ​​the same opening 3" - for example, also detachably - from the outside to the wall 3*, in such a way that the deformation body 12 projects into the same lumen. In particular, the sensor element 1 is inserted into the opening 3" in such a way that the (disk-shaped) membrane segment 12a, together with the edge segment 12b of its deformation body 12, covers or hermetically seals the opening 3". The same opening 3" can, for example, also be designed such that it has - as is quite common in measuring systems of the type in question - an (inner diameter) that lies in a range between 10 mm and approximately 50 mm. According to a further embodiment of the invention, a holder is further formed in the opening 3" for holding the sensor element 1 or its deformation body 12 on the wall 3*. The sensor element 1 can for example by means of material bonding, in particularnamely by welding or soldering, of the deformation body 12, for example its edge segment, and the wall 3* of the tube 3; however, it can also be detachably connected to the tube 3, for example by being screwed or screwed on. In the aforementioned socket, at least one, for example also circumferential or annular, sealing surface can be formed, which is designed to (hermetically) seal the opening 3" in interaction with the deformation body 12 or its membrane segment 12a and a possibly provided, for example annular or annular disk-shaped sealing element. Last but not least, for the previously described case that the sensor element 1 is inserted into the aforementioned socket and / or that the deformation body 12 is to be materially connected to the wall 3* of the tube 3, the deformation body 12 or in an (outer orAccording to a further embodiment of the invention, the sensor element 1 and the tube 3 are further dimensioned such that a (sensor flag) length L12c, measured as a (maximum) distance between the first and second (sensor flag) ends, corresponds to more than half a caliber DN of the tube 3 or less than 95% of the same caliber DN. The (sensor flag) length L12c can, for example, as is quite common with comparatively small calibers of less than 50 mm or as can also be seen from the . Fig. 2 - can also be selected such that the (free) second (sensor flag) end has only a small minimum distance from the wall 3* of the pipe 3. For pipes with a comparatively large caliber of 50 mm or more, the (sensor flag) length L12c can, for example, also be significantly shorter than half a caliber DN of the pipe 3, as is quite common in measuring systems of the type in question.

[0082] In Fig.In the embodiment shown in Figure 2, the measuring system is specifically designed as a vortex flow measuring device with a bluff body 4 arranged in the lumen of the aforementioned tube 3 - here upstream of the (built-in) sensor element 1 - serving to create a Kármán vortex street in the flowing (measurement) fluid. Sensor element 1 and bluff body 4 are specifically dimensioned and arranged such that the deformation body 12 protrudes into the lumen 3* of the tube 3 or the (measurement) fluid conveyed therein in such a region that is regularly occupied by the aforementioned (stationary) Kármán vortex street during operation of the measuring system, so that the alternating forces acting on the deformation body 12 or its sensor vane or the pressure fluctuations detected by the sensor 1 are transmitted to the bluff body 4 at a detachment rate (~1 / f Vtx) detached counter-rotating vortices and the sensor signal s1 has a signal frequency (-f Vtx). In the embodiment shown here, the measuring system is also designed as a measuring system or a vortex flow measuring device in a compact design, in which the measuring electronics 2 is accommodated in a protective housing 20 which is held on the pipe 3, for example by means of a neck-shaped connecting piece 30. According to a further embodiment of the invention, the deformation body 12 or the sensor element formed thereby is furthermore particularly also designed to transmit (alternating) forces F(t) exerted transversely to the (main) flow direction into the (deformation body) cavity or the (annular) gap 1' by the (measuring) fluid flowing in the aforementioned (main) flow direction (of the measuring system), for example due to pressure fluctuations within the aforementioned Kármán vortex street, deforming (cantilever) oscillations x(t) in a direction, in particular transversely to the (main) flow direction z and / or in the direction of the aforementioned (main) detection or

[0083] Measuring direction x of the sensor element 1. Not least for the aforementioned case that the measuring system is designed as a vortex flow measuring device, the sensor element 1 or the measuring system formed therewith can advantageously be designed or aligned such that the (main) detection or measuring direction x of the sensor element 1 runs transversely to the (main) flow direction z, for example in that the aforementioned smallest distance a1 between sensor electrode 12d and reference electrode 13 runs or is measurable essentially perpendicular to the (main) flow direction z and / or in that the surface normals of the aforementioned first and second sensor vane surfaces are aligned essentially orthogonal to the aforementioned (main) flow direction z.

[0084] If necessary, for example in the case of use in a measuring system designed as a vortex flow meter, one or more temperature sensors, for example according to the aforementioned US-B 69 10 387, can also be provided in the sensor element according to the invention and / or one or more of the (protective) measures known from the aforementioned US-B 69 38 496, US-B 97 19 819, US-B 1 08 45 222 or US-B 1 09 48 321 for increasing the (operating) pressure resistance of the sensor element or of a measuring system formed therewith can also be implemented. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US-B 69 10 387 [0002, 0064, 0084] US-B 69 38 496 [0002, 0064, 0084] US-B 97 19 819 [0002, 0064, 0084] US-B 1 08 45 222 [0002, 0064, 0084] US-B 1 09 48 321 [0002, 0064, 0084] Cited non-patent literature

[0000] http: / / www.de.endress.com / en / search?filter.text=prowirl

[0002]

Claims

[1] (Capacitive) sensor element - in particular a sensor element for (capacitively) detecting pressure fluctuations in a Kármán vortex street formed in a flowing fluid and / or a sensor element designed to be contacted by a flowing fluid - comprising a sensor element: - a base body (11), in particular a sleeve-shaped and / or monolithic, in particular made of an electrically conductive material and / or a metal, with a (base body) cavity (11*) having a first end, in particular a circular, open end and a second end, in particular a circular and / or open end; - a deformation body (12) made of an electrically conductive material, in particular having an electrical conductivity of more than 10 at an operating temperature of 20°C 5 S / m exhibiting, material, in particular a metal, -- with a (disc-shaped) membrane segment, -- with a (deformation body) cavity (12*) enclosing the membrane segment, in particular a hollow cylindrical or ring-shaped, edge segment forming a (deformation body) cavity (12*) with an open first end and a closed second end, -- with a sensor flag, in particular plate-shaped and / or wedge-shaped, arranged on a first surface of the membrane segment that is at least partially flat and / or at least partially (convexly) curved, in particular on a first surface of the membrane segment, -- and with a second (membrane segment) surface of the membrane segment arranged on one of the first (membrane segment) surfaces opposite the first (membrane segment) surface, in particular a rod- and / or sleeve-shaped (elongated) sensor electrode; - a, in particular a single, sleeve-shaped, in particular monolithic and / or non-hollow cylindrical, reference electrode (13) made of an electrically conductive material, in particular having an electrical conductivity of more than 10 at an operating temperature of 20°C5 S / m having, material, in particular a metal, with a (reference electrode) cavity having an, in particular non-circular, open first end and a, in particular non-circular and / or open, second end (13*); - and a, in particular, a sleeve-shaped and / or monolithic, packing body (14) made of an electrically non-conductive material, in particular having an electrical conductivity of less than 10 at an (operating) temperature of 20°C -8 S / m having, (insulating) material, in particular a glass, a plastic or a ceramic, with a (filling) cavity having a, in particular circular, open first end and a, in particular circular and / or open, second end (14*); - wherein the reference electrode (13) is partially embedded in the packing material (14) such that at least a first (reference electrode) sub-segment (13a) of the reference electrode (13), in particular by forming a force-fit and / or a form-fit and / or a material-fit, is enclosed by the packing material, in particular at least a second (reference electrode) sub-segment (13b) of the reference electrode (13) adjoining the same first reference electrode sub-segment and encompassing the first end of the (reference electrode) cavity is not enclosed by the packing material (14); - and wherein the filler body (14) together with the (embedded therein) reference electrode (13) is arranged within the base body cavity (11*) such that, -- that the first ends of the filler and the reference electrode face the first end of the base body, -- that a (base body) surface of the base body (11) facing the lumen of the base body cavity (11*) and a (fill body) surface of the fill body (14) facing the same base body surface contact each other, in particular by forming a force-fit and / or a form-fit and / or a material-fit. -- and that the reference electrode (13) and the base body (11) are mechanically coupled to each other via the packing material (14), yet galvanically separated from each other, in particular electrically insulated, in particular such that a minimum electrical resistance R1 between the reference electrode (13) and the base body (11) at an operating temperature of 20°C is not less than 10 MΩ, in particular greater than 50 MΩ; - wherein the deformation body (12) and the base body (11) are mechanically coupled to each other to form a sensor cavity (1*) (involving both a part of the deformation body cavity not occupied by the base body and a part of the base body cavity not occupied by the filler body or the reference electrode, as well as the reference electrode cavity), such that -- that the sensor electrode (of the deformation body) is arranged partially within the reference electrode cavity, forming a (ring) gap (1') between the sensor electrode and the reference electrode (13), in particular a circumferential gap. -- and that a first (basic body) sub-segment of the basic body (11) encompassing the first end of the basic body cavity (11*) and the edge segment of the deformation body (12) are connected to each other by forming an electrically conductive, in particular hermetically sealed, connection, in particular by material bonding and / or form-fitting and / or force-fitting; - wherein the deformation body (12) and the reference electrode (13) are arranged such that a (circular) cylindrical, concave (reference electrode) surface of the reference electrode (13) facing the lumen and a similar (reference electrode) surface, in particular only partially (circular) cylindrical, (sensor electrode) surface of the sensor electrode (of the deformation body) do not contact each other, in particular in such a way that the reference electrode (13) and sensor electrode (12) are galvanically isolated from each other; - and wherein the deformation body (12) is arranged, in particular to perform oscillations around a static rest position, forced by (alternating) forces acting on the deformation body (12), such that the sensor electrode deforms the (ring) gap (1'), thus performing (cantilever) oscillations that change the (sensor) capacitance C1 (of a capacitor formed by means of the deformation body, the filler body and the reference electrode) formed between the deformation body and the reference electrode, in particular when the deformation body is in a static rest position, which is not less than 5 pF and / or not more than 100 pF. [2] Sensor element according to claim 1, wherein the second end of the (reference electrode) cavity (13*) is closed, in particular by means of a plate-shaped cover segment of the reference electrode and / or hermetically. [3] Sensor element according to claim 1, wherein the second end of the (reference electrode) cavity (13*) is open. [4] Sensor element according to one of the preceding claims, wherein the (ring) gap (between reference electrode and sensor electrode) is not rotationally symmetric with respect to an imaginary (sensor electrode) longitudinal axis corresponding to a principal axis of inertia of the sensor electrode and / or is not rotationally symmetric with respect to an imaginary (reference electrode) longitudinal axis corresponding to a principal axis of inertia of the reference electrode, at least when the deformation body is in a static rest position. [5] Sensor element according to any one of the preceding claims, - wherein the reference electrode is not rotationally symmetrical with respect to the imaginary (reference electrode) longitudinal axis, in particular, is not hollow cylindrical; and / or - wherein the sensor electrode is not rotationally symmetrical with respect to the imaginary (sensor electrode) longitudinal axis, in particular is not circularly cylindrical; and / or - wherein the sensor electrode and reference electrode are not arranged coaxially to each other, at least in sections. [6] Sensor element according to any one of the preceding claims, - wherein the (ring) gap (1') is kept free of solids; and / or - wherein no other components of the sensor element are positioned within the (ring) gap (1'); and / or - where a (maximum) relative permittivity established within the (ring) gap is not greater than 3, in particular less than 1.

5. [7] Sensor element according to one of the preceding claims, wherein the deformation body is configured to be contacted by a fluid, in particular a flowing fluid and / or a fluid having a temperature of more than 100°C at least temporarily, in particular a liquid and / or a gas or another fluid. [8] Sensor element according to one of the preceding claims, wherein the deformation body is arranged to be surrounded by a flowing fluid, in particular a liquid and / or a gas, formed in a Kármán vortex street, in particular by (alternating) forces exerted thereon by the fluid. [9] Sensor element according to one of the preceding claims, wherein the deformation body is configured to convert (alternating) forces acting on the sensor flag, in particular exerted by a (circulating) fluid and / or introduced via first and second sensor flag surfaces, into (cantilever) vibrations of the sensor electrode deforming the (sensor) cavity or the (ring) gap. [10] Sensor element according to one of the preceding claims, wherein the sensor vane is configured to convert (alternating) forces exerted by a fluid flowing in a (main) flow direction, in particular due to pressure fluctuations within a Kármán vortex street formed in the flowing fluid, transverse to the (main) flow direction, into (cantilever) vibrations of the sensor electrode deforming the (sensor) cavity or the (ring) gap in a direction of vibration, in particular transverse to the (main) flow direction and / or in the direction of a (main) measuring direction of the sensor element. [11] Sensor element according to one of the preceding claims, wherein the sensor flag has a first sensor flag surface, in particular at least partially planar, and a second sensor flag surface opposite the first sensor flag surface, in particular shaped in the same way as the first sensor flag surface and / or (plan-)parallel and / or at least partially planar. [12] Sensor element according to the preceding claim, wherein the first and second sensor flag surfaces are arranged to be contacted by a fluid, in particular a flowing fluid, in particular a liquid and / or a gas, in particular such that (alternating) forces, which cause (cantilever) vibrations of the sensor electrode and are generated by the fluid via the first and second sensor flag surfaces, are introduced into the deformation body. [13] Sensor element according to one of the preceding claims, wherein the deformation body or sensor flag is arranged to convert (alternating) forces exerted on it in a (main) measuring direction (of the sensor element) into (cantilever) vibrations of the sensor electrode deforming the (deformation body) cavity or the gap. [14] Sensor element according to the previous claim, - wherein a smallest width of the gap (1') lies in or can be measured in the (main) measuring direction; and / or - wherein a maximum width of the gap (1') lies in or can be measured in the (main) measuring direction; and / or - where a smallest width of the gap (1') is opposite or measurable to a largest width of the gap (1'). [15] Sensor element according to one of the preceding claims, wherein a (measuring) capacitor with a (sensor) capacitance C1 determined by the (ring) gap is formed by means of the deformation body, the filler body and the reference electrode, in particular such that the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX of more than 1 pF / mm in a (main) measuring direction or is configured to react to a maximum (deflection) movement ΔX of 1 µm of the sensor electrode in a (main) measuring direction with a change ΔC1 of the capacitance C1 of more than 1 fF. [16] Sensor element according to the previous claim, wherein the (measuring) capacitor has a (measuring) sensitivity ΔC1 / ΔX in a (main) measuring direction, in particular more than 1 pF / mm and / or maximum, such that the (measuring) capacitor is configured to react to a maximum (deflection) movement ΔX of the sensor electrode in a (main) measuring direction, in particular of 1 µm, with a change ΔC1 of the capacitance C1, in particular more than 1 fF. [17] Sensor element according to the previous claim, wherein the (measuring) capacitor has a transverse sensitivity ΔC1 / ΔZ in a direction deviating from the (main) measuring direction, in particular by not less than 50% of the (measuring) sensitivity ΔC1 / ΔX, in particular such that the transverse sensitivity ΔC1 / ΔY is less than the (measuring) sensitivity ΔC1 / ΔX and / or that the (measuring) capacitor is configured to respond to a maximum (deflection) movement ΔZ of the sensor electrode in at least one, in particular each, direction deviating from the (main) measuring direction with a change ΔC1' of the capacitance C1 which is less than the change ΔC1 (of the capacitance C1) with which the (measuring) capacitor reacts to an equally large (deflection) movement ΔX of the sensor electrode in the (main) measuring direction. [18] Sensor element according to any one of the preceding claims, - wherein, in the case of a deformation body in a static rest position, the sensor electrode and the reference electrode are arranged only sectionally coaxially, in particular forming a (measuring) capacitor; and / or - where the greatest distance between the sensor electrode and the reference electrode 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 a smallest width of the (ring) 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 a maximum width of the (ring) 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 - where a maximum width of the (ring) gap (1') is greater than 0.05 mm, in particular greater than 0.1 mm, than a minimum width of the (ring) gap (1'); and / or - wherein the sensor electrode has a (sensor electrode) mass of less than 10 g; and / or - wherein the deformation body has a minimum wall thickness that is not less than 0.4 mm and / or not greater than 2 mm; and / or - wherein the sensor flag has a (sensor flag) mass that is less than 50 g and / or not less than 4 g, in particular such that the (sensor flag) mass is equal to a (sensor electrode) mass of the sensor electrode; and / or - wherein the sensor electrode has a (sensor electrode) length that is less than 50 mm and / or greater than 5 mm. [19] Sensor element according to any one of the preceding claims, - wherein the base body has a length greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm; and / or - wherein the filler has a length greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm; and / or - where the smallest distance between the sensor electrode and the reference electrode 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. [20] Sensor element according to the previous claim, - where the filler length is smaller than the base body length; and / or - where the filler length is smaller than the reference electrode length; and / or - where the base body length is greater than the reference electrode length. [21] Sensor element according to one of the preceding claims, wherein the filler is arranged within the base body cavity such that a partial area of ​​the base body cavity enclosed by the first base body segment (forming the first end of the base body cavity) is not filled or occupied by the filler. [22] Sensor element according to the previous claim, - wherein the reference electrode has a length greater than 10 mm and / or less than 100 mm, in particular such that a (sub-segment) length of the second reference electrode sub-segment is less than 50 mm and / or more than 10 mm and / or less than 50% of the (reference electrode) length and / or more than 10% of the (reference electrode) length; and / or - wherein the reference electrode is at least, in particular only, partially (circular) cylindrical, in particular such that a smallest (cylindrical) diameter of the second reference electrode sub-segment is greater than 3 mm and / or that a smallest (cylindrical) diameter of the first reference electrode sub-segment is greater than a smallest (cylindrical) diameter of the second reference electrode sub-segment; and / or - wherein the second (reference electrode) sub-segment (of the reference electrode) has a (sub-segment) length that is greater than 10 mm and / or less than 100 mm; and / or - wherein the reference electrode is embedded in the packing material in such a way that a third (reference electrode) segment adjacent to the first reference electrode segment, but distant from the second (reference electrode) segment, in particular a sleeve-shaped segment, is not enclosed by the packing material. [23] Sensor element according to one of the preceding claims, wherein at least one second (reference electrode) sub-segment (13b) of the reference electrode (13) adjacent to the first reference electrode sub-segment is not enclosed by the filler body (14). [24] Sensor element according to any one of the preceding claims, - wherein the first (reference electrode) sub-segment (of the reference electrode) has a (sub-segment) length that is greater than 10 mm and / or less than 100 mm; and / or - wherein the second (sensor electrode) sub-segment (of the sensor electrode), in particular to increase a mutual (frequency) difference of natural or resonance frequencies of different vibration modes of the sensor element and / or to increase a (measurement) sensitivity ΔC1 / ΔX of a capacitor C1 formed by means of the deformation body, the filler body and the reference electrode relative to a transverse sensitivity ΔC1 / ΔY of the same capacitor C1, with respect to an imaginary longitudinal axis of the same (sensor electrode) sub-segment, is not rotationally symmetric, in particular such that the second (sensor electrode) sub-segment has a D- and / or T-shaped and / or oval cross-section. [25] Sensor element according to any one of the preceding claims, - wherein the base body consists of a material with a (linear) coefficient of thermal expansion at an (operating) temperature of 20°C greater than 5·10 -6 K -1 , in particular not less than more than 8·10-6 K -1 , and / or less than 25·10 -6 K -1 , in particular not more than 19·10 -6 K -1 , is; and / or - wherein the reference electrode consists of a material with a (linear) coefficient of thermal expansion of less than 11·10 at an (operating) temperature of 20°C -6 K -1 is; and / or - wherein the filler material consists of a material with a (linear) coefficient of thermal expansion at an (operating) temperature of 20°C greater than 5·10 -6 K -1 , in particular not less than 8·10 -6 K -1 , and / or less than 25·10 -6 K -1 , in particular not more than 19·10 -6 K -1 , amounts. [26] Sensor element according to the previous claim, - wherein the coefficient of thermal expansion (of the material) of the base body is not smaller than the coefficient of thermal expansion (of the material) of the reference electrode, in particular such that the coefficient of thermal expansion (of the material) of the base body at an (operating) temperature of 20°C is reduced by more than 1·10 -6 K -1 , in particular by no less than 5·10 -6 K -1 , is greater than the coefficient of thermal expansion (of the material) of the reference electrode; and / or - wherein the coefficient of thermal expansion (of the material) of the base body is not smaller than the coefficient of thermal expansion (of the material) of the filling material, in particular such that the coefficient of thermal expansion (of the material) of the base body at an (operating) temperature of 20°C is reduced by more than 1·10 -6 K -1 , in particular by no less than 5·10 -6 K -1 , is greater than the coefficient of thermal expansion (of the material) of the filler material; and / or - wherein the coefficient of thermal expansion (of the material) of the reference electrode is not greater than the coefficient of thermal expansion (of the material) of the packing material, in particular such that the coefficient of thermal expansion (of the material) of the reference electrode is less than 1·10 -6 K -1 smaller than the coefficient of thermal expansion (of the material) of the filler. [27] Sensor element according to any one of the preceding claims, - wherein the base body, in particular entirely, consists of a metal, in particular a (rust-free) stainless steel (WNr. 1.4404); and / or - wherein the reference electrode, in particular entirely, consists of a metal, in particular a nickel-based alloy (WNr. 2.4475); and / or - wherein the packing material consists at least partially, in particular entirely, of a glass, in particular a melting gas; and / or - wherein the sensor cavity is hermetically sealed; and / or - wherein the base body and the filler material are positively connected to each other at least at an (operating) temperature of less than 400°C; and / or - wherein the packing material and the reference electrode are positively connected to each other at least at an (operating) temperature of less than 400°C. [28] Sensor element according to one of the preceding claims, wherein the sensor cavity is filled with an (inert) gas, in particular nitrogen and / or a noble gas. [29] Sensor element according to any one of claims 1 to 28, wherein the sensor cavity is evacuated. [30] Sensor element according to one of the preceding claims, further comprising: a (first) connecting line electrically connected to the reference electrode, in particular electrically conductively connected to it. [31] Sensor element according to one of the preceding claims, further comprising: a (second) connecting line electrically connected to the base body, in particular electrically conductively connected to it. [32] Measuring system for measuring at least one measured quantity, in particular a flow parameter or a material parameter, of a fluid measured substance, in particular a gas and / or a liquid, in particular a gas and / or a liquid, which is carried in a pipeline and / or has at least a temporary temperature of more than 100°C and / or acts on the deformation body (of the sensor element) with a pressure difference of more than 10 bar, comprising: a sensor element according to one of the preceding claims and an electrically connected (measuring system) electronics. [33] Measuring system according to the previous claim, - wherein the sensor element is configured to respond to a pressure difference of 1 bar acting on the deformation body in a (main) measuring direction (of the sensor element) with a change ΔC1 in capacitance C1 of not less than 10 fF and / or not more than 1 pF; and / or - wherein, by means of the deformation body, in particular by means of the deformation body and the base body, a reference potential, in particular zero, is provided for at least one (signal) voltage to be processed by the measuring electronics or a ground (GND) of the measuring electronics is formed. [34] Using a measuring system according to one of the preceding claims for measuring a flow parameter - in particular a flow velocity and / or a volumetric flow rate and / or a mass flow rate - of a fluid medium, in particular a steam, flowing in a pipeline, in particular a (measuring medium) temperature of more than 100°C and / or with a pressure difference of more than 10 bar acting on the deformation body (of the sensor element).

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