WO2025036593A1

WO2025036593A1 - Sensor unit for a flow meter

Info

Publication number: WO2025036593A1
Application number: PCT/EP2024/066773
Authority: WO
Inventors: Frank Trinter
Original assignee: SIKA Dr. Siebert & Kühn GmbH & Co. KG
Priority date: 2023-08-16
Filing date: 2024-06-17
Publication date: 2025-02-20
Also published as: DE102023121935A1

Abstract

The invention relates to a sensor unit (1) for a flowmeter (100) for measuring the flow rate of a fluid in accordance with the vortex principle, wherein the sensor unit (1) is configured for arrangement in a measuring tube (10) or at another fluid conducting body (10a), wherein the sensor unit (1) has at least one base member (11) and one measuring sensing element, (12), and wherein the measuring sensing element (12) is received in or at the base member (11), In accordance with the invention, the base member (11) has a frame portion (13) that at least partially surrounds the measuring sensing element (12), and with an elastomeric body (14) being provided by means of which the measuring sensing element (12) is held at the frame portion (13). The invention is further directed to a flow meter (100) having such a sensor unit (1).

Description

SENSOR UNIT FOR A FLOW METER

Description

The invention relates to a sensor unit for a flow meter for measuring the flow rate of a fluid in accordance with the vortex principle, wherein the sensor unit is configured for arrangement in a measuring tube of the flow meter, wherein the sensor unit has at least one base member and one measuring sensing element, and wherein the measuring sensing element is received in or at the base member.

PRIOR ART

DE 10 2018 101 278 A1 , for example, discloses a flow meter for measuring the flow rate of a fluid through a measuring tube in accordance with the so- called vortex principle and a bluff body is introduced into the measuring tube at which the fluid undergoes vortex formation when the fluid flows around the bluff body and a sensor unit that projects into the flow region of the fluid and that can sensorily record the vortex produced at the bluff body is introduced into the measuring tube downstream of the bluff body.

The sensor unit has a base member that undergoes a lateral deflection that is caused by the vortices generated at the bluff body. This principle of flow measurement corresponds to the vortex principle and the base member is deflected laterally to the direction of flow based on the shedding frequency of the vortices at the bluff body that rises and falls proportionally to the speed of the fluid in the measuring tube. The periodic vortex shedding at the bluff body can be measured by the measuring sensing element of the sensor unit; for example by the application of a piezo element that forms the major component of the measuring sensing element beside the contacts. In this respect, the principle of the Karman vortex street is used to determine the throughflow speed of the fluid as the primary measured variable from the shedding frequency of the vortices produced at the bluff body. The formation of the vortex street and the strength of the vortices generally depend on the Reynolds number and thus also on the flow velocity.

The sensor units have base members composed of special plastics whose mechanical properties are determined such that a lateral deflection is possible due to the vortex action on the base member and to this extent also on the measuring sensing element. In this respect, the Young’s modulus of the base member may not be selected as too large since otherwise a lateral excursion of the base member sufficient for the technical measurement detection of the voltage signals from the piezo element together with the measuring sensing element can no longer take place. It is in particular important at low flow velocities to ensure an elasticity of the base member by the correct selection of the material in order also to detect a signal that can be sufficiently evaluated with a sufficient signal-to-noise ratio at low flow velocities.

The base members in accordance with the prior art as a rule completely surround the measuring sensing element; the measuring sensing element is, for example, fully cast in or adhered to the material of the base member. The base members of sensor units known per se for such flow meters to this extent have a solid overall structure, whereby the base member as a rule tends to be rigid, but nevertheless remains flexible due to the material selection. A material accordingly has to be selected that has a small Young’s modulus, for example with a value of approximately 500 N/mm² On the selection of other materials that could be considered for the formation of the base member, for example typical thermoplastics such as PA, PPE, PPS, or the like, this would have the result that the base member and thus the sensor unit would have too high a stiffness so that the required lateral deflection of the sensor unit can also no longer take place with a weak vortex action.

DISCLOSURE OF THE INVENTION

The object of the invention comprises the improved design of the sensor unit for a flow meter, whereby a wider spectrum of possible materials for the formation of the base member can be used. In this respect, the base member should be improved such that a sufficient lateral deflection of the measuring sensing element can also be achieved with a weak vortex action.

This object is achieved starting from a sensor unit in accordance with the preamble of claim 1 and also starting from a flow meter having such a sensor unit in accordance with claim 14 by the respective characterizing features. Advantageous further developments of the invention are set forth in the dependent claims.

The invention includes the technical teaching that the base member has a frame portion that at least partially surrounds the measuring sensing element and wherein an elastomeric body is provided by means of which the measuring sensing element is held at the frame portion.

The key idea of the invention is an initially rigid design of the base member with the frame portion that does not itself perform any oscillations, but that supports the measuring sensing element via the elastomeric body such that the measuring sensing element itself can nevertheless perform an oscillating movement. Due to the high yielding capability of the elastomeric body, the measuring sensing element can also oscillate to the side such that a sufficient signal strength is achieved even at small flow velocities, that is with a corresponding small vortex action and thus a small deflection. The frame portion here remains substantially rigid and does not perform any oscillating movement, in particular since it can be formed from a higher strength plastic.

Due to the design of the base member with a frame portion in accordance with the invention, the base member is not formed as a fully solid housing body for the measuring sensing element, but the base member rather forms a frame portion that at least partially or completely surrounds the measuring sensing element, for example on one side, on both sides, or fully circumferentially so that the measuring sensing element is sufficiently stabilized in the direction of flow with respect to the flow of the fluid around the sensor unit, but a movability remains possible transversely to the direction of flow so that the oscillation deflection to generate the measured signal remains possible.

The elastomeric body that can, for example, comprise a silicone or an EPDM (Ethylene Propylene Diene Monomer), with these further materials to be understood as also covered by the term elastomeric body in the sense of the invention serves to provide a sufficiently yielding connection of the measuring sensing element to the rigid frame portion and to hold the measuring sensing element at the frame portion in a suitable manner or to fix it in another manner; the elastomers of the elastomeric body consequently do not have to be purely organic compounds. In accordance with the invention, the elastomeric body forms a suitable means to movably connect the measuring sensing element to the frame portion. The elastomeric body is in particular designed so that the measuring sensing element is at least partially fastened to the frame portion by means of the elastomeric body.

The base member or at least the frame portion of the base member can thus, for example, comprise a thermoplastic material that to this extent has a greater hardness than the elastomeric body. The thermoplastic material can, for example, refer to a PA (polyamide), PPE (polyphenylene ether), or a PPS (polyphenylene sulfide). It in particular becomes possible by the design of the base member of the sensor unit in accordance with the invention to dispense with the use of fluorine based materials, in particular PFAS plastics (polyfluoroalkyl plastics)

The measuring sensing element can have a lance-like extent in a main direction, in particular when the measuring sensing element comprises a piezo element that is contacted by two electrodes. A, for example, rod-like measuring sensing element having, for example, a rectangular cross- sectional area and an elongate extent is thus produced. The frame portion can be designed here such that it supports the measuring sensing element at least laterally on only one side or on two oppositely disposed sides so that a side part extending laterally and in parallel with the main direction of the measuring sensing element forms the frame portion or reproduces a part thereof. Two sides parts extending in parallel with the main direction can in particular form the frame portion, with the measuring sensing element then being able to be received between the two side parts extending in parallel with the measuring sensing element.

It is in particular conceivable in this respect that the frame portion furthermore has a transverse part that extends between the two side parts, that connects the side parts to one another, and that in particular provides a closed frame structure of the frame portion together with the side parts within which the measuring sensing element is arranged. The two side parts and the transverse part can here in particular form a closed structure with a base portion of the base member and all the components of the frame portion can in particular be formed in one part and with material unity with one another. In other words, an O-shaped structure can be produced by the base portion, the two side parts, and the transverse part and the measuring sensing element is inwardly disposed in the O-shaped structure.

A design of the base member is particularly advantageous when its base portion is inserted into or at the measuring tube and can be fastened thereto, with the two side parts in particular projecting from the base portion and forming the closed frame structure of the frame portion together with the transverse part. Worded differently, the two side parts extend between the transverse part and the base portion, with the two side parts that in particular extend in parallel with one another including a right angle with the transverse part seen in the extent thereof. The transverse part can, however, also be arcuate so the no corners are produced in the transition from the transverse part to the side parts.

The elastomeric body can be arranged at the base member with shape fit, friction engagement, or with material continuity. The measuring sensing element can, for example, first be inserted into the elastomeric body so that the elastomeric body is subsequently fastened to the base member. An opening can, for example, be introduced in the base portion into which the elastomeric body can be pushed together with the inserted measuring sensing element until the measuring sensing element is located with the elastomeric body in the inner region of the O-shaped frame portion. In this respect, the elastomeric body is fastened to the measuring sensing element in the base portion via a reception section of the base portion that in the simples case forms an opening of the base portion of the base member and in which the elastomeric body is seated. In addition to a shape fit connection between the elastomeric body and the base member, it is here also possible to adhesively bond the elastomeric body in or to the base member or the elastomeric body is injection molded onto the base member in a two-component injection molding process to only subsequently insert the measuring sensing element. In accordance with a first possible variant to design the sensor unit, the elastomeric body can be formed in sleeve shape and can directly surround the measuring sensing element so that the elastomeric body is surrounded at the outer side by the base member or by the frame portion and the elastomeric body is, for example, fastened to the base member or the frame body with a shape fit, friction engagement, or with material continuity. In this respect, the base member can have a reception section in the base portion, in particular in the form of a passage bore, into which the elastomeric body can be introduced.

A reception groove can furthermore be introduced in the transverse part of the frame portion and the upper end of the elastomeric body can project into or be seated in it while the other end of the elastomeric body remains in the reception section. The movability of the measuring sensing element is thereby somewhat reduced since it is held together with the elastomeric body not only at one side by the reception section at the base member, but is rather still also held via the otherwise free upper end at the frame portion. This measure can be advantageous depending on the area of application, the fluid, and the flow parameters.

The frame portion further advantageously extends in a base plane that is defined by the main direction of the measuring sensing element and the extent of the transverse part and the thickness of the elastomeric body is advantageously smaller than or the same as the thickness of the side part and/or of the transverse part of the frame portion viewed laterally to the base plane. If the fluid is flowed around by the fluid, it is advantageous if the frame portion having the side parts and the transverse part forms a smooth transition to the elastomeric body that is as free of joints as possible with the elastomeric body in other words not projecting beyond the width of the frame portion in the lateral direction. In accordance with a second possible variant of designing the sensor unit, the elastomeric body can be designed such that it can be pushed at least over the frame portion, but also beyond the base portion. The measuring sensing element is thereby held with bending elasticity within the frame portion and laterally to the base plane. The elastomeric body can, for example, be shrunk onto or adhered to the frame portion and also onto or to the measuring sensing element. The elastomeric body can here also adopt the contour of the base member and can in particular have two sections. It is thus conceivable that the elastomeric body has a flat upper section that is pushed over the frame portion and with the flat upper section merging into an enlarged, in particular round, lower section that is pushed over at least a part of the base portion. A joint-free structure of the sensor unit, in particular of the part that comes into contact with the fluid in the measuring tube, is thereby produced.

In accordance with the second possible variant of designing the sensor unit, the elastomeric body can be pushed over the base member and the measuring sensing element together. It is here also conceivable as an alternative that the elastomeric body is injection molded to the frame portion and to the measuring sensing element or is at least injected into the intermediate space between the measuring sensing element and the frame portion in a two-stage injection molding process. Such injection molding processes form part of the prior art and the manufacture of the elastomeric body takes place in an injection molding cavity into which the frame body and the measuring sensing element had previously been placed to subsequently carry out the injection molding of the elastomeric body to the frame portion and to the measuring sensing element.

The elastomeric body can also be shrunk onto the frame portion and the measuring sensing element alternatively to the injection molding. The invention is also directed to a flow meter having a sensor unit such as presented above, wherein the measuring tube extends in a direction of flow and wherein the sensor unit is introduced into the measuring tube such that the direction of flow is disposed in the base plane of the frame portion. The detection of the flow velocity takes place here via the vortex action on the part of the sensor unit projecting into the fluid, with the vortex action generating a bending deflection in the measuring sensing element that takes place transversely to the direction of flow whereas the frame portion is substantially rigid and does not also execute the oscillation movement.

The sensor unit is thus flat at least in that region that projects into the fluid and this forms an overall profile as a rule favorable to the flow. This can be achieved by the geometrical design of the frame portion; to this extent, the frame can be placed flat in the flow in its U-shaped or O-shaped design so that the cross-section of the sensor unit flowed against is minimal, but the measuring sensing element can also undergo the vortex action with and by the elastomeric body and can deflect laterally.

The elastomeric body can further advantageously be sealed toward the measuring tube, for which purpose the elastomeric body can in particular have a peripheral sealing bead at the outer side that can engage in a corresponding recess in the reception point to receive the sensor unit in the measuring tube.

PREFERRED EMBODIMENTS OF THE INVENTION

Further measures improving the invention will be shown in more detail below together with the description of two preferred embodiments of the invention with reference to the Figures. There are shown: Figure 1 a perspective view of a flow meter having a sensor unit inserted into the measuring tube;

Figure 2a a detailed view of the sensor unit in the arrangement at the measuring tube, with the sensor unit corresponding to a first variant;

Figure 2b a detailed view of the sensor unit in the arrangement at the measuring tube, with the sensor unit corresponding to a second variant;

Figure 3 a perspective view of a first variant of the sensor unit without the elastomeric body;

Figure 4 a cross-sectional view of the first variant of the sensor unit with the elastomeric body;

Figure 5 an overall view of the sensor unit in accordance with the first variant;

Figure 6 a perspective view of a second variant of the sensor unit without the elastomeric body;

Figure 7 a cross-sectional view of the second variant of the sensor unit with the elastomeric body; and

Figure 8 an overall view of the sensor unit in accordance with the second variant. Figure 1 shows a flow meter 100 in a perspective view whose main component is formed by a measuring tube 10 that can, for example, be inserted into a pipe that is flowed through by a fluid. The fluid can be water, for example, with the measurement of other liquids such as oils, fuels or other chemicals also being able to be measured with respect to their flow velocities. The measurement takes place by means of a sensor unit 1 that projects into the flow cross-section of the measuring tube 10, wherein, downstream of the arrangement of the sensor unit 1 , a bluff body 25 is placed into the measuring tube 10 at which vortices in the fluid flow can be generated that act on the sensor unit 1 arranged subsequently.

The part of the sensor unit 1 projecting into the measuring tube 10 is laterally deflected by the vortex action, with this deflection being detected by a measuring sensing element 12 as a central part of the sensor unit 1. The measuring sensing element 12 is received in a base member 11 of the sensor unit 1 and is connected to measurement electronics 26 by means of which a measured signal can be output that provides information on the flow velocity of a fluid flowing through the measuring tube 10. This so-called vortex principle is based on the vortex frequency of the vortices forming at the bluff body 25 behaving proportionally to the flow rate of the fluid through the measuring tube 10. If the vortices produced at the bluff body 25 are measured by the sensor unit 1 in that the vortices generate a lateral deflection of the measuring sensing element 12, this deflection can be detected by means of the measuring sensing element 12 and the measurement electronics 26. The measuring sensing element 12 can, for example, comprise a piezo element that generates a voltage on bending strain, with this voltage being able to be correspondingly evaluated by means of the measurement electronics 26.

Figure 2a shows an enlarged view of the arrangement of the sensor unit 1 in the measuring tube 10 in accordance with a first variant and a connection of the measuring sensing element 12 of the sensor unit 1 to the measurement electronics 26 by means of the electrical contact 30 is shown. The sensor unit 1 is inserted into a measurement bore 27 that is introduced into the measuring tube 10 and tapers perpendicular to the direction of flow 23. In this respect, a part of the base member 11 of the sensor unit 1 projects into the flow region within the measuring tube 10 while a base portion 18 of the base member 11 is introduced in the measurement bore 27 and is sealed toward the measuring tube 10 by a seal 28. The variant of the sensor unit 1 shown has an elastomeric body 14 that is arranged above the measuring sensing element 12 and the elastomeric body 14 is encompassed with the measuring sensing element 12 by the frame portion 13 of the base member 11 , with the frame portion 13 extending out of the base portion 18 into the measuring space of the measuring tube 10.

Figure 2b shows an alternative variant of the flow meter 100 in an arrangement at a fluid conducting body 10a that, alternatively to the measuring tube 10 in accordance with Figure 2a, can likewise receive the sensor unit 1. The sensor unit 1 is shown in the form of a second variant in which the elastomeric body 14 surrounds both the frame portion 13 of the base member 11 and equally the measuring sensing element 12. An outwardly circumferential sealing bead 24 of the elastomeric body 14 seals the latter toward the measurement bore 27 in the fluid conducting body 10a.

It is illustrated by this that the flow meter 100 can comprise a measuring tube 10 and measurement electronics 26 beside the sensor unit 1 , but there is also the possibility of arranging the sensor unit 1 at another fluid conducting body 10a and the flow meter 100 has the sensor unit 1 and the measurement electronics 26 as main components, with the bluff body 25 also being able to be a component of the flow meter 100 that is shown in Fig. 1. The flow meter 100 can thus also be provided as a functional unit with the sensor unit 1 and the measurement electronics 26 and/or with the bluff body 25 to be deployed in another fluid conducting body 10a or the sensor unit 1 comprises the measuring tube 10 in accordance with Fig. 1 and can in particular be deployed in a pipe.

Figures 3, 4, and 5 show a first variant of designing the sensor unit 1 having the features of the invention, with the sensor unknit 1 being shown with the base member 11 and the measuring sensing element 12 in Figure 3 while an elastomeric body is not shown. Figure 4 shows the sensor unit 1 in an overall cross-sectional view and Figure 5 shows a perspective view of the sensor unit 1 with the elastomeric body 14.

The sensor unit 1 has a base member 11 as a main component and the base member 11 is divided into a base portion 18 and into a frame portion 13. If the base member 11 is inserted into the measuring tube 10 of the flow meter 100, the base portion 18 can remain in the measuring tube 10 in the measurement bore 27 provided for this purpose, see Fig. 2. A sealing groove 29 serves the reception of the seal 28.

Due to the omission of the elastomeric body 14 in the representation of Figure 3, the measuring sensing element 12 can be seen that is located within the frame portion 13 and position 30 designates the electrical contact of the measuring sensing element 12 to be contacted by the measurement electronics 26 shown in Fig. 2. The frame portion 13 is substantially made up of two side parts 16 and a transverse part 18, with the two side parts 16 extending perpendicular from the base portion 18 and the transverse part 17 in turn extending transversely between the free ends of the side parts 16 and thus forms a closed frame portion 13.

A reception groove 20 that is shown in Figure 3 is introduced at the inner side in the transverse part 17 and the free end of the elastomeric body 14 can be deployed in this reception groove 20 as Figures 4 and 5 show. The base member 11 has a reception section 19 into which the elastomeric body 14 has been inserted at the inner side in the base portion 18. The elastomeric body 14 in accordance with this embodiment is thus held, on the one hand, via the reception section 19 in the base portion of the base member 11 and, on the other hand, via the reception groove 20.

The measuring sensing element 12 extends in a main direction 15, with the direction of extent of the transverse part 17 being additionally shown in Figure 5. In this respect, the frame portion 13 with the two side parts 16 and the transverse part 17 has a flat extent in an extension plane that is spanned by the main direction 15 and the direction of extent of the transverse part 17. If the measuring sensing element 12 is deflected by a vortex action, the deflection takes place transversely to the planar extent of the plane while the frame portion 13 is not deflected or is only deflected to a very small degree. The measuring sensing element 12 is consequently received in the rigid frame portion 13 in an oscillation capable manner, with the elastomeric body 14 serving this purpose.

A second embodiment of a sensor unit 1 having the features of the present invention is shown in Figures 6, 7, and 8. Figure 6 shows the sensor unit 1 also as in Figure 3 without the elastomeric body, with Figure 7 showing the sensor unit 1 with the elastomeric body 14 in cross-section and Figure 8 showing an overall view of the sensor unit 1 with the elastomeric body 14.

This alternative embodiment of the sensor unit 1 in accordance with the invention has a base member 11 having a base portion 18 and a frame portion 13, with, also as in accordance with the first embodiment in accordance with Figures 3, 4, and 5, the measuring sensing element 12 being introduced or encompassed in the O-shaped frame potion 13. In accordance with this embodiment, however, the elastomeric body 14 surrounds both the frame portion 13 and the measuring sensing element 12 so that not only the measuring sensing element 12 has the elastomeric body 14 as an enveloping body, but rather the entire frame portion 13 together with the measuring sensing element 12 is enveloped by the elastomeric body 14. Position 30 here also designates the electrical contact of the measuring sensing element 12 to be contacted by the measurement electronics 26 shown in Fig. 2. The elastomeric body 14 forms the outer skin of the sensor unit 1 at least in the region with which the sensor unit 1 projects into the flow region of the measuring tube 10 of the flow meter 100, see Figure 1 .

The elastomeric body 14 can be adhered to or shrunk onto the base member 11 and/or the measuring sensing element 12; it is alternatively also conceivable that the elastomeric body 14 is injection molded on the frame portion 13 and/or the measuring sensing element 12 in an injection molding process.

The elastomeric body 14 can here be pushed over the whole frame portion 13 while the base portion 18 remans free and in particular remains deployed in the measurement bore 27 within the measuring tube 10. The elastomeric body 14 can, however, cover a part of the base portion so that the elastomeric body 14 can be divided into an upper section 21 and into a lower section 22, with the upper section 21 being flat and being pushed over the frame portion 13, and the lower section 22 can likewise be pushed over at least a part of the base portion 18 that is also seated in the measurement bore in the measuring tube. It is thus advantageously possible that a seal toward the measurement bore 27 in the measuring tube 10 can be made possible by a sealing bead 24 that Is formed outwardly circumferentially at the elastomeric body 14.

The measuring sensing element 12 can also deflect sufficiently in this embodiment so that a sufficient measured signal can be generated despite the elastomeric body 14 surrounding the measuring sensing element 12 together with the frame portion 13 and despite the rigid frame portion 13, without the frame portion 13 co-executing an oscillation deflection.

The base member 11 with the base portion 18 and the frame portion 13 can thus be made from plastics, in particular thermoplastics, having higher Young’s moduli since the basic structure of the base member 11 does not co-oscillate and hold the measuring sensing element 12 while ensuring the oscillation capability in the position. The holding function of the frame portion 13 thus in particular takes place in the direction of flow of the fluid.

The invention is not restricted in its designs to the preferred embodiment specified above. A number of variants is rather conceivable that also makes use of the solution shown with generally differently designed embodiments. All the features and/or advantages, including any construction details or spatial arrangements, originating from the claims, the description or the drawings can be essential to the invention both per se and in the most varied combinations.

Reference numeral list:

1 sensor unit

10 measuring tube

10a fluid conducting body

11 base member

12 measuring sensing element

13 frame portion

14 elastomeric body

15 main direction

16 side part

17 transverse part

18 base portion

19 reception section

20 reception groove

21 upper section

22 lower section

23 direction of flow

24 sealing bead

25 bluff body

26 measurement electronics

27 measurement bore

28 seal

29 sealing groove

30 electrical contact

100 flow meter

Claims

Claims:

1 . A sensor unit (1 ) for a flowmeter (100) for measuring the flow rate of a fluid in accordance with the vortex principle, wherein the sensor unit (1) is configured for arrangement in a measuring tube (10) or at another fluid conducting body (10a), wherein the sensor unit (1) has at least one base member (11 ) and one measuring sensing element (12), and wherein the measuring sensing element (12) is received in or at the base member (11 ), characterized in that the base member (11 ) has a frame portion (13) that at least partially surrounds the measuring sensing element (12), and with an elastomeric body (14) being provided by means of which the measuring sensing element (12) is held at the frame portion (13).

2. A sensor unit (1 ) in accordance with claim 1 , characterized in that the base member (11 ) or at least the frame portion (13) comprises a thermoplastic material that has a greater hardness than the elastomeric body (14).

3. A sensor unit (1 ) in accordance with claim 1 or claim 2, characterized in that the measuring sensing element (12) has a lance-like extent in a main direction (15), with the frame portion (13) having at least one side part (16) extending laterally to the measuring sensing element (12) and in particular in parallel with the main direction (15).

4. A sensor unit (1 ) in accordance with one of the claims 1 to 3, characterized in that the frame portion (13) has a transverse part (17) that extends between the two side parts (16), that connects the side parts (16) to one another, and that in particular provides a closed frame structure of the frame portion (16) together with the side parts (16) within which the measuring sensing element (12) is arranged.

5. A sensor unit (1 ) in accordance with one of the preceding claims, characterized in that the base member (11 ) has a base portion (18) at which the two side parts (16) project and form the closed frame structure of the frame portion (13) together with the transverse part (17).

6. A sensor unit (1 ) in accordance with one of the preceding claims, characterized in that the base portion (18), the two side parts (16), and the transverse part (17) are in one part and have material continuity.

7. A sensor unit (1 ) in accordance with one of the preceding claims, characterized in that the elastomeric body (14) is arranged at the base member (11 ) with shape fit, friction engagement, or with material continuity; or in that the elastomeric body (14) is injection molded on the base member (11).

8. A sensor unit (1 ) in accordance with one of the preceding claims, characterized in that the elastomeric body (14) is sleeve-shaped and surrounds the measuring sensing element (12), with the elastomeric body (14) being partially surrounded at the outer side by the base member (11 ).

9. A sensor unit (1 ) in accordance with claim 8, characterized in that the base member (11 ) has a reception section (19) into which the elastomeric body (14) has been inserted in the base portion (18).

10. A sensor unit (1 ) in accordance with claim 8 or claim 9, characterized in that a reception groove (20) into which the elastomeric body (14) projects at the end side is introduced in the transverse part (17) of the frame portion (13).

11. A sensor unit (1 ) in accordance with one of the claims 8 to 10, characterized in that the frame portion (13) extends in a base plane that is defined by the main direction (15) of the measuring sensing element (12) and the extent of the transverse part (17), with the thickness of the elastomeric body (14) being smaller than or the same as the thickness of the side part (16) and/or of the transverse part (17) of the frame portion (13).

12. A sensor unit (1 ) in accordance with one of the claims 1 to 7, characterized in that the elastomeric body (14) is pushed at least over the frame portion (13), with the measuring sensing element (12) being stabilized laterally to the base plane by means of the elastomeric body (14) within the frame portion (13).

13. A sensor unit (1 ) in accordance with claim 12, characterized in that the elastomeric body (14) has a flat upper section (21 ) that is pushed over the frame portion (13) and with the flat upper section (21 ) merging into an enlarged, in particular round, lower section (22) that is pushed over the base portion (18).

14. A flow meter (100) having a sensor unit (1) in accordance with one of the preceding claims, characterized in that the measuring tube (10) extends in a direction of flow (23), with the sensor unit (1) being introduced into the measuring tube (10) such that the direction of flow (23) is disposed in the base plane of the frame portion (13).

15. A flow meter (100) in accordance with claim 14, characterized in that the elastomeric body (14) is sealed toward the measuring tube (10), in particular by means of an outwardly circumferential sealing bead (24).