Sensor element

Abstract

The invention relates to a sensor element comprising a main body (11) with a (main body) cavity (11*) having an open first end and a second end, a deformation body (12) made of an electrically conductive material, a sleeve-like 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 filling body (14) made of an electrically non-conductive (insulating) material with a (filling body) cavity (14*) having an open first end and a second end. The filling body (14) together with the reference electrode (13) (embedded therein) are arranged within the main body cavity (11*). In addition, the deformation body (12) and the main body (11) are mechanically coupled to one another so as to form a sensor cavity (1*) such that an (elongated) sensor electrode of the deformation body is partly arranged within the reference electrode cavity, thereby forming an (annular) gap (1') between the sensor electrode and the reference electrode (13), and the main body (11) and the deformation body (12) are connected to one another, thereby forming an electrically conductive connection. The deformation body (12) is additionally designed to vibrate about a static rest position in such a way that the sensor electrode carries out (cantilever) vibrations which deform the (annular) gap (1') and thus change a (sensor) capacitance C1 (of a capacitor formed by means of the deformation body, the filling body and the reference electrode) formed between the deformation body and the reference electrode.

Description

[0001] Sensor element

[0002] The invention relates to a (capacitive) sensor element, in particular a sensor element for (capacitive) detecting pressure fluctuations in a Kärmännchen 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.

[0003] In process measurement and automation technology, vortex flowmeters are often used to measure the flow velocities of fluids or fluids flowing in pipelines, especially 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 volume or mass flow rates corresponding to a particular flow velocity. Examples of such measuring systems include US-B 69 10 387,

[0004] 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).

[0005] 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 projecting into the flow in the direction of flow of the measuring system downstream of the bluff body, namely in the area of ​​the aforementioned Kärmän vortex street, which serves to detect pressure fluctuations in the Kärmän 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 v tx).

[0006] 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.

[0007] 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.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.

[0008] To detect pressure fluctuations in the aforementioned Kärmän vortex street, the deformation body of the respective sensor element is specifically designed to perform oscillations around a static rest position, forced 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.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 that comply 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, one object of the invention is to provide a (capacitive) sensor element with high measurement sensitivity, particularly suitable for detecting pressure fluctuations in a Kärmän 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 achieve this object, the invention consists in a (capacitive)

[0011] Sensor element - for example, a sensor element for (capacitive) detecting pressure fluctuations in a Kärmännchen vortex street formed in a flowing fluid and / or a sensor element which is designed to be contacted by a flowing fluid - which sensor element comprises:

[0012] • 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;

[0013] • 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 5S / m, material, for example a metal, with a (disk-shaped) membrane segment, with a (deformation body) cavity, for example a hollow cylindrical or annular edge segment enclosing 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, for example a plate-shaped and / or wedge-shaped, arranged on a first surface of the membrane segment, for example a first surface that is planar at least in sections and / or convexly curved at least in sections, and with a second (membrane segment) surface of the membrane segment, for example a 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;

[0014] • 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 5 S / m, material, for example a metal, with a (reference electrode) cavity having, for example, a 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 body 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 in such a way 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 body) surface of the filler body facing the same base body surface contact each other, for example by forming a frictional connection and / or a positive connection and / or a material connection, and that the reference electrode and the base body are mechanically coupled to each other via the filler body, but are nevertheless galvanically separated from each other, 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 MQ, for example greater than 50 MQ;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), in such a way that the sensor electrode (of the deformation body) is arranged proportionately within the reference electrode cavity to form, for example, a circumferential (annular) gap between the sensor electrode and the reference electrode, and that a first (base body) partial segment of the base body, which encompasses 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, such that the sensor electrode executes (cantilever) oscillations that 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, when the deformation body is in a static rest position, amounting to not less than 5 pF and / or not more than 100 pF.

[0015] 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.

[0016] 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, such as steam, flowing in a pipeline, for example, at a (measured medium) temperature of more than 100°C and / or acting on the deformation body (of the sensor element) with a pressure difference of more than 10 bar. 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 sealed, for example, by means of a plate-shaped cover segment of the reference electrode and / or hermetically.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 ').

[0024] 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. According to a tenth embodiment of the sensor element of the invention, it is further provided that the deformation body is configured 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.

[0025] 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 Kärmänn vortex street, and, for example, to be elastically deformed by (alternating) forces exerted thereon by the fluid.

[0026] 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.

[0027] 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 Kärmän 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.

[0028] 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.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) vibrations 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 lies opposite or is measurable to a largest width of the gap. Alternatively or additionally, the smallest width of the gap can lie or be measurable in the (main) measuring direction and / or the largest width of the gap can lie or be 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 AC1 / AX of more than 1 pF / mm in a (main) measuring direction or is set up to react to a maximum (deflection) movement AX of 1 pm of the sensor electrode in a (main) measuring direction with a change AC1 of more than 1 fF in the capacitance C1.Further developing this embodiment of the invention, it is further provided that the (measuring) capacitor has a (measuring) sensitivity AC1 / AX in a (main) measuring direction (of the sensor element), for example more than 1 pF / mm and / or greatest, such that the (measuring) capacitor is set up to react to a maximum (deflection) movement AX of the sensor electrode in a (main) measuring direction, for example amounting to 1 pm, with a change AC1 in the capacitance C1, for example amounting to more than 1 fF.In addition, the (measuring) capacitor can advantageously have a transverse sensitivity AC1 / AY in a direction deviating from the (measuring) sensitivity AC1 / AX, for example by not less than 50% of the (measuring) sensitivity AC1 / AX, for example in such a way that the transverse sensitivity AC1 / AY is smaller than the (measuring) sensitivity AC1 / AX and / or that the (measuring) capacitor is designed to react to a maximum (deflection) movement AZ of the sensor electrode in at least one, for example each, direction deviating from the (main) measuring direction with a change AC1 ' of the capacitance C1 that is smaller than the change AC1 (of the capacitance C1) with which the (measuring) capacitor reacts to an equally large (deflection) movement AX of the sensor electrode in the (main) measuring direction.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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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 ').

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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 that is less than 50 mm and / or greater than 5 mm. 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 that is greater than 5 mm and / or less than 100 mm, for example, not greater than 50 mm.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 AC1 / AX of a capacitor C1 formed by means of the deformation body, the filler body and the reference electrode relative to a transverse sensitivity AC1 / AY 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.

[0042] 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 that is greater than 10 mm and / or less than 100 mm. 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 encased 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.

[0043] 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 8-1 O' 6 K -1 , and / or less than 25-10' 6 K -1, for example, no more than 19-10 -6 K' 1 , amounts.

[0044] 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 of which a (linear) thermal expansion coefficient at an (operating) temperature of 20°C is less than 11 -10 6 K' 1 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 whose (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, no 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 5-1 O' 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.

[0045] 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).

[0046] 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).

[0047] 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.

[0048] According to a thirty-ninth embodiment of the sensor element of the invention, it is further provided that the sensor cavity is hermetically sealed. According to a fortieth embodiment of the sensor element of the invention, it is further provided that the base body and filler body are non-positively connected to one another at least at an (operating) temperature of less than 400°C.

[0049] 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.

[0050] 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.

[0051] According to an embodiment of the measuring system of the invention, it is further provided that the sensor cavity is evacuated.

[0052] 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.

[0053] 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.

[0054] 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 AC1 in the capacitance C1 of not less than 10 fF and / or not more than 1 pF.

[0055] According to a second embodiment of the second further 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) is formed for the measuring electronics. A basic idea of ​​the invention is, among other things, to provide a (capacitive) sensor element with high measuring sensitivity and high pressure and / or temperature resistance by detecting deformation movements of the deformation body relative to a sleeve-shaped (single) reference electrode placed within the base body and converting this into a change in the (sensor) capacitance or a corresponding (capacitive) electrical measuring signal. The sensor element according to the invention has (while still maintaining high measuring accuracy orgood resolution of vortex-based vibrational movements) has a mechanical and electrical structure that is comparatively easy to manufacture and also very robust.

[0056] 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:

[0057] Fig. 1 a, b in different views an embodiment of a (capacitive) sensor element according to the invention;

[0058] Fig. 2a, b the sensor element according to Fig. 1 a and 1 b in further different side views;

[0059] Fig. 3 the sensor element according to Fig. 1 a or 1 b in a sectional side view;

[0060] Fig. 4a, b, c show in different views a further embodiment of a (capacitive) sensor element according to the invention; and

[0061] Fig. 5a, b show schematically in various views an embodiment of a measuring system formed by means of a sensor element according to the invention. In Figs. 1a, 1b, 2a and 2b, an embodiment of a (capacitive) sensor element according to the invention is shown schematically in various views. The sensor element serves in particular to detect pressure fluctuations in a flowing medium or in a Kärmän vortex street formed in a flowing fluid and to convert them into a (capacitive) sensor signal. Advantageously, as can also be seen from Fig. 5b, the sensor element can, for example, also be used as a component or part of a device for measuring at least one flow parameter, which may also be time-variable, such as a flow velocity v and / or a volume flow V', of a (measurement) fluid flowing in a pipeline, for example a hot, in particularThe measuring system (MS) may be designed for a gas or liquid which is at least temporarily at a temperature of more than 100°C and / or at least temporarily under a high pressure, in particular of more than 10 bar.

[0062] The sensor element 1 comprises, as shown in Fign. 1 b and 3 respectively, or readily apparent from a view of Fig. 1 a, 1 b, 2a, 2b and 3 together, 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 an open first end and an open second end (reference electrode) cavity 13* and a, for example sleeve-shaped and / or monolithic, filler body 14 with a (filler) cavity 14* having, for example, a circular, open first end and a (filler) 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, also correspond, for example, to a base body or deformation body 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.

[0063] 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 connecting 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 connecting 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, such 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.

[0064] 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.

[0065] 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 , especially not less than more than 8-10 -6 K' 1 , and / or less than 25-10' 6 K' 1 , especially 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 -1 O' 6 K' 1 and / or the filler body 14 is made of a material having a (linear) thermal expansion coefficient of more than 5-10 -6 K' 1 , especially not less than 8-10' 6 K' 1 , and / or less than 25-10' 6 K -1 , especially 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 smaller 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 smaller 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 by more than 1 -10' 6 K -1 , especially by no 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 , especially by no 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.

[0066] 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 be 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 such that a region adjacent to the first reference electrode sub-segment 13a, but nevertheless separated from the second.

[0067] The third (reference electrode) sub-segment of the reference electrode, which is removed from the first (reference electrode) sub-segment and then forms or encloses the second end of the reference electrode (in the same way as the previously designated second reference electrode sub-segment), is not covered by the filler body 14.

[0068] In the sensor element according to the invention, the filler body 14 is arranged together with the reference electrode 13 (embedded therein) within the base body cavity 11* in such a way that, as also shown in Fig. 1 b, 2b or 3 or 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 body 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 the 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, in such a way that a (smallest) electrical resistance R1 between reference electrode 13 and base body 11 at an (operating) temperature of 20°C is not less than 10 MQ, in particular.namely, greater than 50 MQ, 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, not least to protect against mechanical overload or damage, is further arranged within the base body cavity 11* such that a portion of the base body cavity enclosed 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 14. The base body and the reference electrode can advantageously be joined by 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 the filler body is then 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.

[0069] 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 not occupied by the filler body 14 or the reference electrode 13, but which nevertheless contains the reference electrode cavity 13* itself, in such a way that, as also shown 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) partial segment of the base body 11 containing the first end of the base body cavity 11* and the edge segment of the deformation body 12 to form an electrically conductive, in particular hermetically sealed, connection, in particular are connected to each other in a materially bonded and / or form-fitting and / or force-fitting manner.In addition, 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. 1 b, 2b or 3 or also easily apparent from their combination, is arranged proportionately within the reference electrode cavity, forming a, in particular, circumferential, (annular) gap 1' between the sensor electrode and the reference electrode 13, as a result of which a (measuring) capacitor of the sensor element comprising the base body 11, the deformation body 12, the filler body 14 and the reference electrode 13 is formed; This can be achieved, for example, by designing the measuring capacitor as an (ideally coaxial) cylindrical capacitor or by designing the measuring capacitor as a cylindrical capacitor with a non-coaxial electrode geometry, as shown in Figs. 1b, 2b, 3, 4a, 4b, or 4c, among others. As shown schematically in Fig. 3 or in conjunction with Fig.1b, 2b and 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 one another; this is particularly also achieved in such a way that the reference electrode and the deformation body are galvanically decoupled from one another or galvanically separated from one another. According to a further embodiment of the invention, it is further provided that a (maximum) relative permittivity s 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.

[0070] 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, for example (see r @oHz = s r = s / so = 1) or, for example, filled with an (inert) gas, in particular a noble gas (He, Ar) and / or nitrogen (N).

[0071] 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 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 AX(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, when the deformation body is in a static rest position, is, for example, not less than 5 pF and / or not more than 100 pF. 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 execute the aforementioned cantilever oscillations AX(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.

[0072] To effect the aforementioned vibrations of the deformation body, in particular the cantilever vibrations AX(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 Kärmän vortex street and / or in such a way that the aforementioned (alternating) forces F(t) (forcing mechanical vibrations of the deformation body) are exerted on the sensor vane by the flowing fluid. According to a further embodiment of the invention, the sensor flag 12c, which is for example plate-shaped and / or wedge-shaped, has a first sensor flag surface, in particular a flat one at least in sections, and a first sensor flag surface opposite the first sensor flag surface, in particular a flat one.a second sensor flag surface that is at least partially flat and / or shaped identically to the first sensor flag surface. The first and second sensor flag surfaces can advantageously also 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 the aforementioned (main) measuring direction (x-direction) of the sensor element or define the same measuring direction.

[0073] 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).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, which is 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 2b, is not hollow-cylindrical at least in sections, for example such that its (open) first end and / or its second end is not circular, for example, elliptical or oval, or that its lumen is not circular-cylindrical at least in sections.Accordingly, at least the second (reference electrode) sub-segment 13b can advantageously be designed to be non-rotationally symmetrical, at least in sections, with respect to an imaginary (sub-segment) longitudinal axis of the same (reference electrode) sub-segment, for example, such 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 optionally present third (reference electrode) sub-segment can also be designed to be non-rotationally symmetrical, at least in sections, with respect to a respective imaginary (sub-segment) longitudinal axis, for example, oval-shaped, especially in a region forming the respective second end of the reference electrode. According to a further embodiment of the invention, it is provided that the sensor electrode 12d, as also shown in Fig.4a, 4b and 4c are each shown or are readily apparent from their combination (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 is done, 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 indicated in Fig. 4a and 4b, oval-shaped. According to a further embodiment of the invention, the reference electrode and the deformation body are designed and arranged in particular such that a smallest distance a1 between the sensor electrode 12d and the reference electrode 13 ora smallest width of the gap 1' is greater than 0.01 mm, for example also greater than 0.1 mm, and / or smaller than 1 mm, for example also smaller than 0.5 mm, and / or that a distance a2 between the reference electrode 13 and the sensor electrode 12d which is opposite the smallest distance a1 (diametrically) or a measurable width of the gap 1' which is opposite the smallest width (diametrically) 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 is also the case, for example, 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.

[0074] According to a further embodiment of the invention, the (measuring) capacitor in the aforementioned (main) measuring direction of the sensor element further comprises a

[0075] (Measurement) sensitivity AC1 / AX of more than 1 pF / mm (picofarad per millimeter) or the (measurement) capacitor is configured to react to a maximum (deflection) movement AX of 1 pm (micrometer) of the sensor electrode in the aforementioned (main) measuring direction with a change AC1 in the capacitance C1 of more than 1 fF (femtofarad). Advantageously, the (measurement) capacitor or the sensor element formed thereby can further be configured such that the capacitor has a maximum (measurement) sensitivity AC1 / AX, in particular more than 1 pF / mm, in the aforementioned (main) measuring direction; This is particularly true in such a way that the (measuring) capacitor reacts to a maximum (deflection) movement AX of the sensor electrode of more than 1 pm and / or less than 5 pm in the aforementioned (main) measuring direction with a change AC1 in the capacitance C1 of more than 1 fF. Alternatively or additionally, the (measuring) capacitor orthe sensor element formed thereby may further be designed such that the (measuring) capacitor has a transverse sensitivity AC1 / AZ in a direction deviating from the (main) measuring direction which deviates from the (measuring) sensitivity AC1 / AX, for example by not less than 50% of the (measuring) sensitivity AC1 / AX; this in particular also in such a way that the transverse sensitivity AC1 / AZ, in particular by not less than 50% of the (measurement) sensitivity AC1 / AX, is smaller than the (measurement) sensitivity AC1 / AX and / or that the (measurement) capacitor reacts to a (deflection) movement AZ of the deformation body 12, in particular more than 1 pm, in at least one, in particular every, direction deviating from the (main) measuring direction with a change AC1 ' of the capacitance C1 which is smaller than the change AC1 (of the capacitance C1) with which the (measurement) capacitor reacts to a (deflection) movement AX of the deformation body 12 in the (main) measuring direction x.The sensor element according to the invention can, as already mentioned several times, for example also be a component of a measuring system used to measure one or more flow parameters of a (measurement) fluid flowing in a pipeline, an exemplary embodiment of which is shown schematically in Fig. 5a and 5b. The aforementioned pipeline - not shown here - can, for example, be designed as a system component of a heat supply network or a turbine circuit, and thus the (measurement) fluid or the medium 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. The (measurement) fluid can, however, also be, for example, water, a (compressed) natural gas or biogas, or gaseous orliquefied hydrogen, thus the pipeline can 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 intended or designed to detect pressure fluctuations in the (measuring) fluid flowing past 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.

[0076] As can be seen from the combination of Figs. 5a and 5b, in addition to the sensor element, the measuring system further comprises (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 to generate measured values ​​XM ZU representing at least one flow parameter, for example the flow velocity v or the volume flow rate V'. The measured values ​​XM can, 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); however, it can also be formed, for example, 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 11 electrically connected to its reference electrode 13, in particular electrically connected thereto. Furthermore, the sensor element can, for example, also comprise a further (second) connecting line 12, which also serves for electrical connection to the (measuring system) electronics and can advantageously be electrically connected to the base body 11 or electrically connected thereto.Alternatively or additionally, a reference potential, for example zero, for at least one (signal) voltage to be processed by the measuring electronics can be provided by means of the deformation body 12 or by means of the deformation body 12 and the base body 11, or advantageously also a ground (GND) of the measuring electronics 2 can be formed.

[0077] According to a further embodiment of the invention, the measuring system MS further comprises a tube 3 insertable into the aforementioned pipeline, having a lumen 3' enclosed by a—for example, metallic—wall 3* of the tube, which extends from an inlet end 3+ to an outlet end 3# and is designed to guide the fluid flowing in the pipeline. In the embodiment shown in Fig. 2 and 5a, a flange is provided at the inlet end 3+ and at the outlet end 3#, respectively, for establishing a leak-free flange connection with a corresponding flange on a line segment of the pipeline on the inlet or outlet side. Furthermore, the tube 3 is essentially straight here, for example, as a hollow cylinder with a circular cross-section, such that the tube 3 has an imaginary straight longitudinal axis L3 imaginarily connecting the inlet end 3+ and the outlet end 3#.The sensor element 1 is inserted from the outside through an opening 3" formed in the wall 3* (Fig. 4c) into the lumen of the tube 3 and is fixed in the area of ​​the same opening 3" - for example, also detachably - from the outside to the wall 3*, specifically 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 (disc-shaped).

[0078] Membrane segment 12a, together with the edge segment 12b of its deformation body 12, covers or hermetically seals the opening 3". This opening 3" can, for example, also be designed such that it has an inner diameter in a range between 10 mm and approximately 50 mm, as is quite common in measuring systems of the type in question. According to a further embodiment of the invention, a holder is further formed in the opening 3" to hold the sensor element 1 or its deformation body 12 on the wall 3*. The sensor element 1 can be fixed to the tube 3, for example, by a material-to-material connection, in particular by welding or soldering, of the deformation body 12, for example its edge segment, and the wall 3*; however, it can also be detachably connected to the tube 3, for example, by being screwed or bolted on.Furthermore, at least one sealing surface, for example a circumferential or annular ring-like one, can be formed in the aforementioned socket, 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-like, sealing element. 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, a further sealing surface, for example annular ring-like, matching the sealing surface of the socket can advantageously be formed into the deformation body 12 or in an edge region (outer or corresponding to the aforementioned sealing surface of the socket) of the first membrane segment surface of the membrane segment 12a.According 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 Fig. 2—also be selected such that the (free) second (sensor flag) end has only a small minimum distance from the wall 3* of the tube 3. In the case of pipes with a comparatively large calibre of 50 mm or more, the (sensor flag) length L12c can, as is quite common in measuring systems of the type in question, also be significantly shorter, for example, than half of a calibre DN of the pipe 3.

[0079] In the embodiment shown in Fig. 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 namely upstream of the (built-in) sensor element 1 - which serves to create a Kärmän 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 projects into the lumen 3* of the tube 3 or the (measurement) fluid conveyed therein in an area which is regularly occupied by the aforementioned (stationary) Kärmän vortex street during operation of the measuring system, so that the alternating forces orthe pressure fluctuations detected by the sensor 1 correspond to periodic pressure fluctuations caused by counter-rotating vortices detached at the bluff body 4 at a shedding rate (~1 / fvtx), and the sensor signal s1 has a signal frequency (~fvtx) corresponding to the shedding rate of these vortices. In the exemplary 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 housed in a protective housing 20 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 orthe sensor element formed thereby is furthermore particularly also designed to convert (alternating) forces F(t) exerted transversely to the (main) flow direction by the (measuring) fluid flowing in the aforementioned (main) flow direction (of the measuring system), for example due to pressure fluctuations within the aforementioned Kärmän vortex street, into (cantilever) oscillations x(t) deforming the (deformation body) cavity or the (annular) gap 1' in an oscillation direction pointing, in particular, transversely to the (main) flow direction z and / or in the direction of the aforementioned (main) detection or 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 in such a way that the (main) detection orMeasuring 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 orthogonally to the aforementioned (main) flow direction z.

[0080] 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.

Claims

PATENT CLAIMS 1 . (Capacitive) sensor element - in particular a sensor element for (capacitive) detecting pressure fluctuations in a Kärmännchen vortex street formed in a flowing fluid and / or a sensor element which is designed to be contacted by a flowing fluid - which sensor element comprises: - a base body (11), in particular a sleeve-shaped and / or monolithic base body, in particular made of an electrically conductive material and / or a metal, with a (base body) cavity (11*) having an open first end, in particular a circular one, and an open second end, in particular a circular and / or open second 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 material, in particular a metal, - with a (disc-shaped) membrane segment, - with a membrane segment, in particular a hollow cylindrical or annular edge segment, enclosing the membrane segment to form a (deformation body) cavity (12*) having an open first end, in particular a circular one, 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, in particular a first surface which is at least partially flat and / or at least partially (convex) curved, - and with a second (membrane segment) surface of the membrane segment, in particular a 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, in particular 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°C 5S / m material, in particular a metal, with a (reference electrode) cavity (13*) having an open first end, in particular a non-circular one, and a second end, in particular a non-circular and / or open one; - and a, in particular sleeve-shaped and / or monolithic, filler 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 (insulating) material, in particular a glass, a plastic or a ceramic, with a (filler) cavity (14*) having an open first end, in particular a circular one, and a second end, in particular a circular and / or open one; - wherein the reference electrode (13) is partially embedded in the filler body (14) such 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 frictional connection and / or a positive connection and / or a material connection, in particular at least a second (reference electrode) sub-segment (13b) of the reference electrode (13) adjacent to the same first reference electrode sub-segment and enclosing the first end of the (reference electrode) cavity is not enveloped by the filler body (14); - and wherein the filler body (14) together with the reference electrode (13) (embedded therein) is arranged within the base body cavity (11*), 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 (11) facing the lumen of the base body cavity (11 *) and a (filler) surface of the filler 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 one another via a filler body (14), but are nevertheless galvanically separated from one another, in particular electrically insulated, in particular such that a smallest 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 MQ, in particular greater than 50 MQ; - wherein the deformation body (12) and the base body (11) are mechanically coupled to one another to form a sensor cavity (1*) (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 a, in particular, circumferential, (annular) gap (1') between the sensor electrode and the reference electrode (13) - and that a first (base body) partial segment of the base body (11) encompassing the first end of the base body cavity (11*) and the edge segment of the deformation body (12) are joined to form an electrically conductive, in particular hermetically sealed, Connection, in particular materially and / or positively and / or non-positively connected; - wherein the deformation body (12) and the reference electrode (13) are arranged such that a (the lumen) facing the reference electrode cavity, in particular a (circular) cylindrical, concave (reference electrode) surface of the reference electrode (13) and a (sensor electrode) surface of the sensor electrode (of the deformation body) facing the same (reference electrode) surface, in particular only partially (circular) cylindrical, do not contact each other, in particular such that the reference electrode (13) and the sensor electrode (12) are kept galvanically separated from each other; - and wherein the deformation body (12) is designed, in particular, to carry out oscillations around a static rest position, which are forced by (alternating) forces acting on the deformation body (12), in such a way that the sensor electrode carries out (cantilever) oscillations which deform the (annular) gap (1'), thus changing 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, 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 (annular) gap (between reference electrode and sensor electrode) is not rotationally symmetrical 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 symmetrical 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 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 the reference electrode are not arranged coaxially to each other, at least in sections.

6. Sensor element according to one of the preceding claims, - wherein the (annular) gap (1 ') is kept free of solids; and / or - wherein no further components of the sensor element are positioned within the (annular) gap (1'); and / or - whereby a (maximum) relative permittivity established within the (annular) 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 liquid and / or a gas or another fluid, in particular a fluid that is flowing and / or has a (fluid) temperature of more than 100°C at least temporarily.

8. Sensor element according to one of the preceding claims, wherein the deformation body is configured to be flowed around by a flowing fluid, in particular a fluid formed into a Kärmänn vortex street, in particular a liquid and / or a gas, in particular to be elastically deformed 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 vane, in particular 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.

10. Sensor element according to one of the preceding claims, wherein the sensor vane is configured to convert (alternating) forces exerted thereon by a fluid flowing in a (main) flow direction, in particular due to pressure fluctuations within a Kärmän vortex street formed in the flowing fluid, transversely to the (main) flow direction into (cantilever) oscillations of the sensor electrode deforming the (sensor) cavity or the (annular) gap in a direction of oscillation pointing, in particular transversely 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 a first sensor flag surface which is flat in at least some sections, and a second sensor flag surface which is opposite the first sensor flag surface and in particular has the same shape and / or is (plane-)parallel and / or is flat in at least some sections to the first sensor flag surface.

12. Sensor element according to the preceding claim, wherein the first and second sensor flag surfaces are configured to be contacted by a, in particular flowing, fluid, in particular a liquid and / or a gas, in particular 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.

13. Sensor element according to one of the preceding claims, wherein the deformation body or the sensor flag is configured to convert (alternating) forces exerted thereon 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 preceding claim, - wherein a smallest width of the gap (1') lies or is measurable in the (main) measuring direction; and / or - wherein a largest width of the gap (1') lies or is measurable in the (main) measuring direction; and / or - wherein 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 co-determined by the (annular) 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 AC1 / AX of more than 1 pF / mm in a (main) measuring direction or is set up to react to a maximum (deflection) movement AX of 1 pm of the sensor electrode in a (main) measuring direction with a change AC1 of more than 1 fF in the capacitance C1.

16. Sensor element according to the preceding claim, wherein the (measuring) capacitor has a (measuring) sensitivity AC1 / AX in a (main) measuring direction, in particular more than 1 pF / mm and / or greatest, such that the (measuring) capacitor is configured to react to a maximum (deflection) movement AX of the sensor electrode in a (main) measuring direction, in particular amounting to 1 pm, with a change AC1 in the capacitance C1, in particular amounting to more than 1 fF.

17. Sensor element according to the preceding claim, wherein the (measuring) capacitor has a transverse cross section which deviates from the (measuring) sensitivity AC1 / AX, in particular by not less than 50% of the (measuring) sensitivity AC1 / AX, in a direction deviating from the (main) measuring direction. Sensitivity AC1 / AZ, in particular such that the transverse sensitivity AC1 / AY is smaller than the (measurement) sensitivity AC1 / AX and / or that the (measurement) capacitor is set up to react to a maximum (deflection) movement AZ of the sensor electrode in at least one, in particular each, direction deviating from the (main) measuring direction with a change AC1 ' of the capacitance C1 which is smaller than the change AC1 (of the capacitance C1) with which the (measurement) capacitor reacts to an equally large (deflection) movement AX of the sensor electrode in the (main) measuring direction.

18. Sensor element according to one of the preceding claims, - wherein, when the deformation body is in a static rest position, the sensor electrode and the reference electrode, in particular forming a (measuring) capacitor, are arranged coaxially only in sections; and / or - wherein the maximum 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 (annular) gap (1') is greater than 0.01 mm, in particular greater than 0.1 mm, and / or less than 1 mm, in particular less than 0.5 mm; and / or - wherein a maximum width of the (annular) gap (1 ') is greater than 0.02 mm, in particular greater than 0.2 mm, and / or less than 1 mm, in particular less than 0.5 mm; and / or - wherein a largest width of the (annular) gap (1') is more than 0.05 mm, in particular more than 0.1 mm, larger than a smallest width of the (annular) gap (1'); and / or - wherein the sensor electrode has a (sensor electrode) mass that is less than 10 g; and / or - wherein the deformation body has a minimum wall thickness which 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 one of the preceding claims, - wherein the base body has a (base body) length that is greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm; and / or - wherein the filler body has a (filler body) length that is greater than 5 mm and / or less than 100 mm, in particular not greater than 50 mm; and / or - wherein a 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 preceding claim, - where the packing length is smaller than the base body length; and / or - where the packing 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 body is arranged within the base body cavity in such a way that a partial region 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.

22. Sensor element according to the preceding claim, - wherein the reference electrode has a (reference electrode) length that is greater than 10 mm and / or less than 100 mm, in particular 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 - wherein the reference electrode is at least, in particular only, partially (circularly) cylindrical, in particular 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; 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 filler body in such a way that a third (reference electrode) sub-segment of the reference electrode, in particular a sleeve-shaped sub-segment, which is adjacent to the first reference electrode sub-segment but is remote from the second (reference electrode) sub-segment, is not encased by the filler body.

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 same first reference electrode sub-segment is not covered by the filler body (14).

24. Sensor element according to 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 for increasing a mutual (frequency) distance between natural or resonant frequencies of different oscillation modes of the sensor element and / or for increasing a (measurement) sensitivity AC1 / AX of a capacitor C1 formed by means of the deformation body, the filler body and the reference electrode relative to a transverse sensitivity AC1 / AY of the same capacitor C1, is not rotationally symmetrical with respect to an imaginary longitudinal axis of the same (sensor electrode) sub-segment, in particular 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.

25. Sensor element according to one of the preceding claims, - the base body being made 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 8-1 O' 6 K -1 , and / or less than 25-10' 6 K -1 , in particular not more than 19-1 O' 6 K' 1 , and / or - wherein the reference electrode is made of a material having a (linear) thermal expansion coefficient of less than 11 -10' at an (operating) temperature of 20°C 6 K -1 and / or - wherein the filler 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 8-1 O' 6 K -1 , and / or less than 25-10' 6 K -1 , especially not more than 19-10' 6 K -1 , amounts.

26. Sensor element according to the preceding claim, - wherein the thermal expansion coefficient (of the material) of the base body is not less than the thermal expansion coefficient (of the material) of the reference electrode, in particular 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 , especially 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 - whereby 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, in particular 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 , especially by no less than 5-10' 6 K -1 , is greater than the thermal expansion coefficient (of the material) of the filler; and / or - wherein 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, in particular 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.

27. Sensor element according to one of the preceding claims, - the base body, in particular entirely, consists of a metal, in particular a (stainless) stainless steel (WNo. 1.4404); and / or - wherein the reference electrode, in particular entirely, consists of a metal, in particular a nickel-based alloy (WNo. 2.4475); and / or - wherein the filler body consists at least partially, in particular completely, 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 body are connected to each other by force at least at an (operating) temperature of less than 400°C; and / or - wherein the filler body and the reference electrode are connected to each other in a force-locking manner 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 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 thereto.

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 thereto.

32. Measuring system for measuring at least one measurand, in particular a flow parameter or a material parameter, of a fluid medium, in particular a gas and / or a liquid, which is guided in a pipeline and / or at least temporarily has a (measured material) 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 (measurement system) electronics electrically connected thereto.

33. Measuring system according to the previous claim, - wherein the sensor element is 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 AC1 in the 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. Use of a measuring system according to one of the preceding claims for measuring a flow parameter - in particular a flow velocity and / or a volume flow rate and / or a mass flow rate - of a fluid medium flowing in a pipeline, in particular a vapor, 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).

Images