Magnetically inductive flowmeter, temperature measurement arrangement, and flowmeter having a temperature measurement arrangement of this kind
Patent Information
- Application Number
- EP2024712171
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-10
- Filing Date
- 2024-03-08
- Publication Date
- 2025-11-26
AI Technical Summary
Magnetic-inductive flowmeters and temperature measuring devices face challenges in achieving a hygienic seal, particularly in applications like the pharmaceutical and food industries, where traditional sealing methods can lead to gaps and dead spaces, compromising hygiene standards.
The use of conical sealing elements with angled inner and outer contours, combined with a sleeve and spring element preload, ensures maximum compression occurs in a quasi-linear sealing area, providing a reliable and gap-free seal that meets hygiene guidelines, such as EHEDG or 3A standards.
This solution ensures a hygienic seal is maintained, allowing for reliable and permanent installation of measuring electrodes and temperature sensors, while preventing short circuits and meeting stringent hygiene requirements, thus ensuring accurate flow and temperature measurements.
Smart Images
Figure EP2024056233_19092024_PF_FP_ABST
Abstract
Description
[0001] Magnetic-inductive flowmeter, temperature measuring arrangement and flowmeter with such a temperature measuring arrangement
[0002] The invention relates to a magnetic-inductive flowmeter according to the preamble of claim 1, a temperature measuring arrangement according to the preamble of claim 11 and a flowmeter according to the preamble of claim 21.
[0003] Magnetic-inductive flowmeters, whose operation is based on the principle of electromagnetic induction (= Faraday induction), have been known for many years and are used extensively in industrial measurement technology. According to the law of induction, an electric field strength perpendicular to the flow direction and perpendicular to the magnetic field is created in a flowing medium that carries charge carriers and flows through a magnetic field. This law of induction is exploited in magnetic-inductive flowmeters by using a magnetic field generating device, which usually has two energized magnetic coils, to generate a magnetic field that is guided at least partially through the measuring tube. The generated magnetic field has at least one component that is perpendicular to the flow direction.Within the magnetic field, each volume element of the flowing medium moving through the magnetic field and containing a certain number of charge carriers contributes, with the field strength generated in this volume element, to a measuring voltage that can be tapped off via the electrodes.
[0004] Since the induced voltage tapped across the electrodes is proportional to the flow velocity of the medium averaged over the cross-section of the measuring tube, the volume flow can be determined directly from the measured voltage, assuming the diameter of the measuring tube is known. The only prerequisite for using a magnetic-inductive flowmeter is a minimum conductivity of the medium. Furthermore, it must be ensured that the measuring tube is filled with the medium at least enough so that the level is above the measuring electrodes.
[0005] Such measuring devices are well known, for example from the German patent specifications DE 10 2007 004 827 B4 and DE 10 2007 004 826 B4, and are essentially characterized in that the magnetic coils and the electrodes are arranged directly on or in the wall of the measuring tube.
[0006] The measuring electrodes usually consist of a cylindrical base body and an electrode head that is in contact with the medium. The electrode head is typically mushroom-shaped or conical, as is known, for example, from DE 10 2015 112 018 B3 or DE 10 2021 127 943 B3, but can also have a conical outer contour directed toward the medium, as is known from CN 2 09 197 811 U.
[0007] In addition to flow measurement, it may also be necessary to measure the temperature of the flowing medium to compensate for temperature influences. Temperature is known to have a significant impact on the physical and chemical properties of the medium, which in turn can affect the measurement result. If the temperature of the medium is known, appropriate correction factors can be determined that make the measurement results comparable under different temperature conditions.
[0008] For example, the German patent DE 10 2010 001 993 B4 discloses a magnetic inductive flowmeter with a temperature measuring device, whereby in addition to the temperature measurement, a measurement of a minimum conductivity is also possible.
[0009] Temperature sensors typically consist of a cylindrical base body and a sensor head that is in contact with the medium. The electrode head is typically mushroom-shaped, as is known, for example, from DE 10 2021 127 942 A1.
[0010] In order to avoid a short circuit between the two measuring electrodes on the one hand and to meet the requirements of applications in the pharmaceutical and food industries on the other, it is known from the prior art that the measuring tube is lined or coated on the inside, for example, with a liner made of PFA or PTFE. These materials are comparatively soft, so that, as can be seen, for example, from Fig. 3 of DE 10 2021 127 943 B3, the measuring electrodes, i.e. the undersides of the electrode heads, are drawn into the soft material during assembly, thus creating a hygienic seal between the measuring electrodes and the measuring tube. The same sealing concept is also used when a pin-shaped temperature sensor is arranged in such a measuring tube of a flow meter, since in addition to measuring the flow, the medium temperature is often also of interest. Such a temperature sensor is known, for example, from DE 10 2021 127 942 A1.
[0011] A hygienic seal meets the requirements of at least EHEDG or 3A and is characterized in particular by the absence of gaps and dead spaces in the area of the transition between the electrode head and the measuring tube or liner.
[0012] The object of the invention is to propose an alternative sealing of the measuring electrodes of the magnetic-inductive flow meter or the temperature sensor of a temperature measuring arrangement, which is also suitable for hygienic applications.
[0013] The object is achieved according to the invention by a magnetic-inductive flowmeter having the features of claim 1, by a temperature measuring arrangement having the features of claim 11, and by a flowmeter having the features of claim 21. Advantageous embodiments of the invention are specified in the subclaims.
[0014] In a first aspect, the invention relates to a magnetic-inductive flowmeter. The invention focuses on measuring electrodes comprising a base body and an electrode head that is in contact with the medium and has a conical outer contour directed toward the medium. The electrode head of each measuring electrode is arranged in an opening in the wall of the measuring tube.
[0015] According to the invention, a sealing element with a conical inner contour is located between the electrode head and the wall of the measuring tube. The outer contour of the electrode head and the inner contour of the sealing element are at an angle to one another, so that maximum compression of the sealing element occurs exclusively in a quasi-linear sealing area facing the medium. The angle is to be selected such that the outer contour and the inner contour approach each other towards the medium, i.e. the inner and outer surfaces of the electrode head and sealing element taper towards the medium. With regard to conical contours, it should be noted that this term is not to be interpreted strictly in a mathematical-geometric sense and therefore slight deviations from a conical shape, i.e. contours with a slight radius, are also to be understood under this term.
[0016] If the measuring tube or the inside of the measuring tube is made of or coated with a relatively hard material, e.g. polyetheretherketone (PEEK), the aforementioned quasi-linear sealing area is created in the front area in contact with the medium. Because the maximum compression of the sealing element occurs exclusively in this area, corresponding hygiene guidelines are met. The sealing element is preferably also made of polyetheretherketone (PEEK). However, various other materials for the measuring tube coating are also conceivable. Examples would be enamel / Rilsan / SOL-GEL or other non-conductive coatings. The sealing element can also be made of various thermoplastics or elastomers. Material variants would be, for example, PSU, PPSU, PEI as well as elastomers such as FKM, EPDM or silicones or similar.
[0017] An advantageous development provides that a sleeve with a through-bore is arranged in the opening in the wall of the measuring tube. This sleeve is firmly bonded, preferably welded, to the wall of the measuring tube. The sealing element and the measuring electrode are arranged in the through-bore. The measuring tube and sleeve are preferably made of metal.
[0018] A first alternative to this advantageous development provides that the through-bore of the sleeve also has, at least in part, a conical inner contour, and the sealing element has a conical outer contour and is formed with a uniform thickness. The sealing element can thus be made comparatively thin, and the coaxially arranged second conical inner and outer contours create a stop during assembly that limits the screw-in depth of the measuring electrode or electrode head. In this embodiment, too, the outer contour of the sealing element and the inner contour of the sleeve are advantageously at an angle to one another, so that maximum compression of the sealing element occurs exclusively in the quasi-linear sealing area facing the medium.In contrast, a second alternative to this advantageous development provides that the through-bore of the sleeve is cylindrical and the sealing element has a cylindrical outer contour and is thicker in the area of the electrode base body than in the area of the electrode head. An axial stop is preferably achieved here by forming a shoulder in the through-bore of the sleeve, against which shoulder the sealing element rests with its end face opposite the medium. In this embodiment, too, maximum compression of the sealing element is achieved exclusively in the quasi-linear sealing area facing the medium, in that the sealing element is advantageously arranged with an oversize in the sleeve.
[0019] To meet the requirements of relevant hygiene guidelines, such as EHEDG or 3A, at least the transitions between the sealing element and the electrode head are flush. If the previously described sleeve is present, the transitions between the measuring tube wall and the sleeve, as well as between the sleeve and the sealing element, are also flush.
[0020] For reliable and permanent installation of the measuring electrodes on or in the measuring tube, a particularly advantageous development of the invention provides that the base bodies of the measuring electrodes have an external thread at their ends opposite the electrode head, onto which a nut is screwed, so that the measuring electrodes are firmly connected to the measuring tube. A spring element is arranged between the measuring tube and the nut, coaxial to the longitudinal axis of the measuring electrodes. A particularly advantageous feature of this embodiment is that the spring element is subjected to a defined preload when the nut is screwed on, wherein a limiting element is arranged coaxially to the common longitudinal axis of the spring element and measuring electrode, which limit the compression of the spring element.The preload of the spring element, which is preferably designed as a disc spring, generates a restoring force that guarantees the required surface pressure. The limiting element allows the spring force of the spring element to be adjusted, yet still allows higher forces to be transmitted during retraction without exceeding the permissible stresses of the spring element. In a second aspect, the invention relates to a temperature measuring arrangement.
[0021] According to the invention, the sensor head of the temperature sensor is arranged in an opening in the wall of the measuring tube and has a conical outer contour directed towards the medium. Furthermore, according to the invention, a sealing element with a conical inner contour is arranged between the sensor head and the wall of the measuring tube. According to the invention, the outer contour of the sensor head and the inner contour of the sealing element are at an angle to one another, so that maximum compression of the sealing element occurs exclusively in a quasi-linear sealing area facing the medium. The angle is to be selected such that the outer contour and the inner contour approach each other towards the medium, i.e. the inner and outer surfaces of the sensor head or sealing element taper towards the medium.With regard to conical contours, it should be noted that this term is not to be interpreted strictly in the mathematical-geometric sense and therefore slight deviations from a conical shape, e.g. contours with a slight radius, are also to be understood under this term.
[0022] If the measuring tube or the inside of the measuring tube is made of a relatively hard material or is coated, e.g. polyetheretherketone (PEEK), the aforementioned quasi-linear sealing area is created in the front area that comes into contact with the medium. Because the maximum compression of the sealing element occurs exclusively in this area, corresponding hygiene guidelines are met. The sealing element is preferably also made of polyetheretherketone (PEEK). However, various other materials for the measuring tube coating are also conceivable. Examples would be enamel / Rilsan / SOL-GEL or other non-conductive coatings. The sealing element can also be made of various thermoplastics or elastomers. Material variants would be, for example, PSU, PPSU, PEI as well as elastomers such as FKM, EPDM or silicones or similar.
[0023] An advantageous development provides that a sleeve with a through-bore is arranged in the opening in the wall of the measuring tube. This sleeve is firmly bonded, preferably welded, to the wall of the measuring tube. The sealing element and the temperature sensor are arranged in the through-bore. The measuring tube and sleeve are preferably made of metal.
[0024] A first alternative to this advantageous development provides that the through-bore of the sleeve also has, at least in part, a conical inner contour, and the sealing element has a conical outer contour and is formed with a uniform thickness. The sealing element can thus be made comparatively thin, and the coaxially arranged second conical inner and outer contours create a stop during assembly that limits the screw-in depth of the temperature sensor or sensor head. In this embodiment, too, the outer contour of the sealing element and the inner contour of the sleeve are advantageously at an angle to one another, so that maximum compression of the sealing element occurs exclusively in the quasi-linear sealing area facing the medium.
[0025] In contrast, a second alternative to this advantageous development provides that the through-bore of the sleeve is cylindrical and the sealing element has a cylindrical outer contour and is thicker in the area of the temperature sensor base body than in the area of the sensor head. An axial stop is preferably achieved here by forming a shoulder in the through-bore of the sleeve, against which the sealing element rests with its end face opposite the medium. In this embodiment, too, maximum compression of the sealing element is achieved exclusively in the quasi-linear sealing area facing the medium, in that the sealing element is advantageously arranged with an oversize in the sleeve.
[0026] To meet the requirements of relevant hygiene guidelines, such as EHEDG or 3A, at least the transitions between the sealing element and the sensor head are flush. If the previously described sleeve is present, the transitions between the measuring tube wall and the sleeve, as well as between the sleeve and the sealing element, are also flush.
[0027] For reliable and permanent installation of the temperature sensor on or in the measuring tube, a particularly advantageous development of the invention provides that the base body of the temperature sensor has an external thread at its end opposite the sensor head, onto which a nut is screwed, so that the temperature sensor is firmly connected to the measuring tube. A spring element is arranged between the measuring tube and the nut coaxially to the longitudinal axis of the temperature sensor. It is particularly advantageous in this embodiment that the spring element experiences a defined preload when the nut is screwed on, wherein a limiting element is arranged coaxially to the common longitudinal axis of the spring element and temperature sensor, which limit the compression of the spring element.The preload of the spring element, which is preferably designed as a disc spring, creates a restoring force that guarantees the required surface pressure. With the limiting element, the spring force of the spring element can be adjusted and higher forces can still be transmitted during retraction without exceeding the permissible stresses of the spring element.
[0028] In a third aspect, the invention relates to a flowmeter. According to the invention, the flowmeter has a temperature measuring arrangement as described above.
[0029] The invention is explained in more detail below using exemplary embodiments with reference to the drawings.
[0030] They show schematically:
[0031] Figure 1 is a sectional view of a magnetic-inductive flowmeter according to the invention or of a temperature measuring arrangement according to the invention according to a first embodiment;
[0032] Figure 2 is an enlarged section of a partial area from Fig. 1;
[0033] Figure 3 is an exploded view of Figure 2;
[0034] Figure 4 shows an enlarged section of a partial area of a magnetic-inductive flowmeter according to the invention or of a temperature measuring arrangement according to the invention according to a second embodiment;
[0035] Figure 5 is an exploded view of Fig. 4 and Figure 6 is an enlarged view of a section of Fig. 4.
[0036] In the following description of the preferred embodiments, like reference numerals designate like or comparable components.
[0037] Since the structure and functioning of the invention can be applied in the same way to pin-shaped measuring electrodes of a magnetic-inductive flowmeter as well as to pin-shaped temperature sensors of a temperature measuring arrangement, both applications are considered in parallel below.
[0038] Figure 1 shows a sectional view of a magnetic-inductive flowmeter 1 according to the invention, consisting of a measuring tube 2, each of which has a flange arranged on its end face, and two measuring electrodes 10 with a corresponding structure. However, the magnetic field generating device required for the measurement has been omitted. Similarly, Figure 1 can also be viewed as a sectional view of a temperature measuring arrangement 1 according to the invention, which consists of a measuring tube 2, each of which has a flange arranged on its end face, and two temperature sensors 10.
[0039] The inside of the measuring tube 2 is coated with a comparatively hard and non-conductive material. PEEK is particularly suitable for this purpose due to its good chemical resistance and suitability for hygienic applications. However, various other materials are also conceivable for the measuring tube coating. Examples would be enamel / Rilsan / SOL-GEL or other non-conductive coatings. In the area of the measuring electrodes 10 or temperature sensors 10, the measuring tube 2 is reshaped to create a flat surface. In the center of this surface is an opening 3 in which the measuring electrodes 10 or temperature sensors 10 are arranged.
[0040] Figure 2 shows an enlarged view of the area marked “A” in Figure 1 and Figure 3 shows an exploded view thereof, each of which shows a first embodiment of the invention.
[0041] A sleeve 4 with a through-opening 4a is welded into the opening 3, the media-side surface of which is also coated. The measuring electrode 10 or the temperature sensor 10 is inserted into this sleeve 4 with a sealing element 20. The measuring electrode 10 consists of a cylindrical base body 11 and an electrode head 12, just as the temperature sensor 10 consists of a cylindrical base body 11 and a sensor head 12. In the embodiment as a temperature sensor 10, a temperature sensor (not shown in detail) is arranged on the front side inside the sensor head 12. This temperature sensor is designed, for example, as a PTC or NTC element and is electrically contacted via stranded wires that are guided through the base body 11. The sealing element surrounds the measuring electrode 10 or the temperature sensor 10 essentially only in the area of the electrode head 12 or sensor head 12 and is advantageously also made of PEEK.
[0042] What is essential to the invention is that the electrode head 12 or sensor head 12 has a conical outer contour and the sealing element 20 has a conical inner contour and both are at an angle to one another, so that after assembly, maximum compression of the sealing element 20 occurs exclusively in a quasi-linear sealing area facing the medium, thus achieving a hygienic seal. Assembly is essentially carried out by screwing a nut 13 onto the end of the base body 11 opposite the electrode or sensor head 12. Previously, a spring element 14, which advantageously consists of disc springs, together with a corresponding structure that includes a limiting element 15, was pushed onto the base body 11. By screwing on and tightening the nut 13, the spring element 14 is subjected to a defined preload. The spring element 14, which is coaxial to the common longitudinal axis of the spring element 14 and the measuring electrode 10 orThe limiting element 15 arranged in front of the temperature sensor 10 limits the compression of the spring element 14. The preload of the spring element 14 generates a restoring force which guarantees the required surface pressure, and the limiting element 15 can be used to adjust the spring force of the spring element 14 and still transmit higher forces during retraction without exceeding the permissible stresses of the spring element 14.
[0043] The first embodiment of the invention shown in Figs. 2 and 3 is characterized in that the sleeve 4 at least partially also has a conical inner contour and the sealing element 20 also has a conical outer contour. The sealing element 20 can thus be made comparatively thin and with a uniform thickness. The outer contour of the sealing element 20 and the inner contour of the sleeve 4 are also at an angle to one another, ensuring that maximum compression of the sealing element 20 occurs exclusively in the quasi-linear sealing area facing the medium. The more or less coaxially arranged second conical inner and outer contours result in a stop during assembly that limits the screw-in depth of the measuring electrode 10 or the electrode head 12 or of the temperature sensor 10 or the sensor head 12.
[0044] Figures 4 and 5 are to be viewed analogously to Figures 2 and 3 and show a second embodiment of the invention. This is characterized in that the through-bore 4a of the sleeve 4 is cylindrical and the sealing element 20 has a cylindrical outer contour. In the area of the base body 11, the sealing element 20 is thicker than in the area of the electrode head 12. An axial stop is realized via a shoulder in the through-bore 4a of the sleeve 4, on which the sealing element 20 rests with its end face opposite the medium. Because the sealing element 20 is advantageously arranged with an oversize in the sleeve 4, this embodiment also contributes to achieving maximum compression of the sealing element 20 exclusively in the quasi-linear sealing area facing the medium. In addition, with this embodiment, the coating of the measuring tube 2 can take place while the sealing element 20 is already installed.Thus, a continuous coating up to the electrode or sensor head 12 can be realized.
[0045] In all embodiments, it is ensured that at least the transitions between the sealing element 20 and the electrode or sensor head 12 are flush. If the sleeve 4 is present, the transitions between the measuring tube wall 2 and the sleeve 4 and between the sleeve 4 and the sealing element 20 are also flush. The arrangement is therefore easy to clean and gap-free, so that the requirements of the corresponding hygiene guidelines are met. The front-flush maximum compression of the sealing element 20 by the sealing element 20 arranged with an oversize in the sleeve 4 and that the outer contour of the sealing element 20 and the inner contour of the sleeve 4 are at an angle to one another is illustrated in Figure 6, which can also be transferred accordingly to the first embodiment.
[0046] List of reference symbols
[0047] 1 magnetic-inductive flowmeter, temperature measuring arrangement
[0048] 2 measuring tube
[0049] 3 Opening
[0050] 4 sleeve
[0051] 4a Passage opening
[0052] 10 measuring electrodes, temperature sensor
[0053] 11 Basic body
[0054] 12 Electrode head, sensor head
[0055] 13 Mother
[0056] 14 Spring element
[0057] 15 Boundary element
[0058] 20 sealing element
Claims
Patent claims 1. A magnetic-inductive flowmeter for measuring the flow of a flowing, conductive medium, comprising a measuring tube (2) made at least partially of a non-conductive material, a magnetic field generating device for generating a magnetic field passing through the measuring tube (2) perpendicular to the longitudinal axis of the measuring tube (2), and two pin-shaped measuring electrodes (10) for tapping a measuring voltage induced in the flowing medium. The measuring electrodes (10) are arranged along a connecting line running perpendicular to the longitudinal axis of the measuring tube (2) and perpendicular to the magnetic field direction. The measuring electrodes (10) comprise at least one base body (11) and one electrode head (12) which is in contact with the medium and has a conical outer contour directed towards the medium. The electrode head (12) of each measuring electrode (10) is arranged in an opening (3) in the wall of the measuring tube (2).characterized in that a sealing element (20) with a conical inner contour is arranged between the electrode head (12) and the wall of the measuring tube (2), wherein the outer contour of the electrode head (12) and the inner contour of the sealing element (20) are at an angle to each other, so that maximum compression of the sealing element (20) occurs exclusively in a quasi-linear sealing area facing the medium.
2. Magnetic-inductive flow meter according to claim 1, characterized in that a sleeve (4) with a through-bore (4a) is arranged in the opening (3) in the wall of the measuring tube (2), which is materially connected to the wall of the measuring tube (2) and in whose through-bore (4a) the sealing element (20) and the measuring electrode (10) are arranged.
3. Magnetic-inductive flowmeter according to claim 2, characterized in that the through-bore (4a) of the sleeve (4) at least partially also has a conical inner contour and the Sealing element (20) has a conical outer contour and is formed with a uniform thickness.
4. Magnetic-inductive flowmeter according to claim 2, characterized in that the through-bore (4a) of the sleeve (4) is cylindrical and the sealing element (20) has a cylindrical outer contour and is thicker in the region of the electrode base body (11) than in the region of the electrode head (12).
5. Magnetic-inductive flow meter according to claim 4, characterized in that the through-bore (4a) of the sleeve (4) has a shoulder on which the sealing element (20) rests with its end face opposite the medium.
6. Magnetic-inductive flowmeter according to one of the preceding claims, characterized in that at least the transitions between the sealing element (20) and the electrode head (12) are flush.
7. Magnetic-inductive flowmeter according to one of the preceding claims, characterized in that the base bodies (11) of the measuring electrodes (10) have an external thread at their ends opposite the electrode head (12), onto which a nut (13) is screwed, such that the measuring electrodes (10) are firmly connected to the measuring tube (2), and a spring element (14) is arranged between the measuring tube (2) and the nut (13) coaxially to the longitudinal axis of the measuring electrodes (10).
8. Magnetic-inductive flowmeter according to claim 7, characterized in that the spring element (14) experiences a defined preload by screwing on the nut (13), wherein a limiting element (15) is arranged coaxially to the common longitudinal axis of the spring element (14) and the measuring electrode (10), which limiting element is suitable for limiting the compression of the spring element (14).
9. Magnetic-inductive flowmeter according to one of the preceding claims, characterized in that the sealing element (20) is made of a thermoplastic or elastomer and the measuring tube (2) is lined internally with a liner made of a non-conductive material.
10. Magnetic-inductive flowmeter according to claim 9, characterized in that the sealing element (20) and the measuring tube (2) consist at least partially of polyetheretherketone (PEEK).
11. Temperature measuring arrangement (1) for determining a temperature of a medium, with a measuring tube (2) consisting at least partially of a non-conductive material and at least one temperature sensor (10), wherein the temperature sensor (10) comprises at least one pin-shaped base body (11) and a sensor head (12) in which a temperature sensor is arranged and which is in contact with the medium, characterized in that the sensor head (12) is arranged in an opening (3) in the wall of the measuring tube (2) and has a conical outer contour directed towards the medium and that between the sensor head (12) and the wall of the measuring tube (2) a sealing element (20) with a conical inner contour is arranged, wherein the outer contour of the sensor head (12) and the inner contour of the sealing element (20) are at an angle to one another, so that a maximum compression of the sealing element (20) exclusively in a quasi-linear,sealing area facing the medium.
12. Temperature measuring arrangement according to claim 11, characterized in that in the opening (3) in the wall of the measuring tube (2) a sleeve (4) with a through-bore (4a) is arranged, which is materially connected to the wall of the measuring tube (2) and in whose through-bore (4a) the sealing element (20) and the temperature sensor (10) are arranged.
13. Temperature measuring arrangement according to claim 12, characterized in that the through-bore (4a) of the sleeve (4) at least partially also has a conical inner contour and the sealing element (20) has a conical outer contour and is formed with a uniform thickness.
14. Temperature measuring arrangement according to claim 12, characterized in that the through-bore (4a) of the sleeve (4) is cylindrical and the sealing element (20) has a cylindrical outer contour and is thicker in the region of the base body (11) than in the region of the sensor head (12).
15. Temperature measuring arrangement according to claim 14, characterized in that the through-bore (4a) of the sleeve (4) has a shoulder on which the sealing element (20) rests with its end face opposite the medium.
16. Temperature measuring arrangement according to one of claims 11 to 15, characterized in that at least the transitions between the sealing element (20) and the sensor head (12) are flush.
17. Temperature measuring arrangement according to one of claims 11 to 16, characterized in that the base body (11) has an external thread at the ends opposite the sensor head (12), onto which a nut (13) is screwed, such that the temperature sensor (10) is firmly connected to the measuring tube (2), and a spring element (14) is arranged between the measuring tube (2) and the nut (13) coaxially to the longitudinal axis of the temperature sensor (10).
18. Temperature measuring arrangement according to claim 17, characterized in that the spring element (14) experiences a defined preload by screwing on the nut (13), wherein a limiting element (15) is arranged coaxially to the common longitudinal axis of the spring element (14) and the temperature sensor (10), which limiting element is suitable for limiting the compression of the spring element (14).
19. Temperature measuring arrangement according to one of claims 11 to 18, characterized in that the sealing element (20) is made of a thermoplastic or elastomer and the measuring tube (2) is lined inside with a liner made of a non-conductive material.
20. Temperature measuring arrangement according to claim 19, characterized in that the sealing element (20) and the measuring tube (2) consist at least partially of polyetheretherketone (PEEK).
21. Flow meter for measuring the flow of a flowing medium, with a measuring tube (2) consisting at least partially of a non-conductive material, characterized in that the flow meter has a temperature measuring arrangement according to one of claims 11 to 20.