Ultrasonic flowmeter and measuring arrangement

Abstract

Ultrasonic flow meter (1) for determining the flow of a medium, with a measuring tube (2) for insertion into a first pipe (4) of a pipe system at the location of a flange connection, with at least one ultrasonic transducer (11) arranged in the measuring tube (2) for transmitting and / or receiving ultrasonic signals, with at least one control and evaluation unit (5) which, in the mounted state, is arranged outside the pipe system and with a connecting element (3) for realizing an electrical connection between the ultrasonic transducer (11) and the control and evaluation unit (5), wherein the connecting element (3) is clamped in the mounted state between a first flange of the first pipe (4) and a second flange of a second pipe (6) and realizes an electrical connection from the interior of the pipe system to the exterior of the pipe system and wherein the connecting element (3) is at least partially formed by a printed circuit board (3a) having at least one electrical line.

Description

[0001] The invention relates to an ultrasonic flow meter for determining the flow of a medium, with a measuring tube for insertion into a first pipe of a pipe system at the location of a flange connection, with at least one ultrasonic transducer arranged in the measuring tube for transmitting and / or receiving ultrasonic signals, with at least one control and evaluation unit which, when installed, is arranged outside the pipe system.

[0002] Furthermore, the invention relates to a measuring arrangement.

[0003] Ultrasonic flowmeters have been known in the art for many years. Functionally, ultrasonic flowmeters comprise a measuring tube for conveying the medium and at least one ultrasonic transducer configured as a transmitter and / or receiver. Furthermore, an ultrasonic flowmeter comprises a control and evaluation unit configured to control the at least one ultrasonic transducer and to evaluate the measurement data.

[0004] For example, the documents US 3 745 824 A and WO 2010 / 002432 A1 each disclose an ultrasonic flow meter with a measuring tube that can be inserted into a pipe of a pipe system.

[0005] The ultrasonic flowmeter in question is designed such that the measuring tube is configured for insertion into a first pipe of a pipe system at the location of a flange connection. Unlike other ultrasonic flowmeters known from the prior art, whose measuring tube forms an independent part of the pipe system, the measuring tube of the ultrasonic flowmeter in question is inserted into a pipe, so that the first tube virtually encloses the measuring tube.

[0006] Since the at least one ultrasonic transducer is arranged in the measuring tube and is thus also located in the interior of the first tube when the ultrasonic flow meter is inserted into the first tube of the pipe system, it is necessary to realize an electrical connection between the interior of the pipe system and the exterior of the pipe system, since the control and evaluation unit is arranged in the exterior of the pipe system.

[0007] The object of the invention is therefore to provide an ultrasonic flowmeter in which an electrical connection between an ultrasonic transducer arranged inside the pipe system and a control and evaluation unit arranged outside the pipe system is realized in a particularly flexible manner. Furthermore, the object of the invention is to provide a corresponding measuring arrangement.

[0008] The object is achieved according to a first teaching of the present invention in that the ultrasonic flowmeter has a connecting element for realizing an electrical connection between the ultrasonic transducer and the control and evaluation unit, wherein the connecting element is clamped in the assembled state between the first flange of the first pipe and the second flange of the second pipe and realizes an electrical connection from the interior of the pipe system to the exterior of the pipe system and wherein the connecting element is at least partially formed by a printed circuit board having at least one electrical line.

[0009] According to the invention, it was recognized that the region of a flange connection of a pipe system can be advantageously used for carrying out an electrical connection into the exterior of the pipe system by using a connecting element which comprises a circuit board, preferably a printed circuit board.

[0010] Particularly preferably, the circuit board has a plurality of electrical lines. It is further preferred if the electrical line or lines are arranged internally within the circuit board.

[0011] In a particularly preferred embodiment of the ultrasonic flowmeter according to the invention, the connecting element has at least one substantially circular fastening section, in particular for connection to the measuring tube. For this purpose, the connecting element has a circular recess, wherein the connecting element, in the assembled state, is arranged such that the medium flows through the recess. The fastening section is arranged around the recess.

[0012] Particularly preferably, holes are arranged in the fastening area, via which, for example, the measuring tube can be screwed to the connecting element.

[0013] According to a further preferred embodiment, the connecting element has at least one contact element in the fastening section for contacting the at least one ultrasonic transducer. Particularly preferably, the connecting element has a plurality of contact elements, so that each existing ultrasonic transducer can be connected to a contact element.

[0014] According to a further preferred embodiment, the bores and the contact elements are arranged in a circle around the recess of the connecting element.

[0015] In a preferred variant, the diameter of the recess in the mounting section corresponds to the inner diameter of the measuring tube. This has the advantage that the measuring tube and the connecting element are flush with each other when mounted, so that the flow in the transition area between the measuring tube and the connecting element is not or only slightly disrupted. This can prevent or at least reduce the formation of vortices in the medium.

[0016] In an alternative variant, the diameter of the recess in the mounting section is larger than the inner diameter of the measuring tube. This design also has only a minimal impact on the flowing medium.

[0017] A particularly preferred embodiment of the ultrasonic flowmeter according to the invention is characterized in that the connecting element, when inserted into the pipe system, extends into a sealing region of the pipe system in the flange connection and at least partially creates a seal for the pipe system in the region of the flange connection. Particularly preferably, a further recess for receiving an external sealing means is introduced into the connecting element. For example, a sealing ring can be inserted into the further recess in order to improve the tightness. Alternatively or additionally, an additional sealing means is applied to the connecting element. The additional sealing means is not only inserted, but is directly connected to the connecting element. For example, the connecting element can have a rubber coating.

[0018] If the connecting element has a circular fastening section, the circular fastening section preferably extends into the sealing area of ​​the pipe system in the flange connection and creates a seal.

[0019] A further embodiment of the ultrasonic flowmeter according to the invention is characterized in that the connecting element has an external contact section that extends into the exterior of the pipe system when inserted into the pipe system. This external contact section preferably has at least one contact element for connecting a line leading to the control and evaluation unit.

[0020] A further embodiment of the ultrasonic flow meter according to the invention is characterized in that the measuring tube has a measuring tube flange for fastening the measuring tube in the installed state of the measuring tube, wherein the fastening in the installed state of the measuring tube and the connecting element is realized by clamping between the first flange of the first tube and the second flange of the second tube of the pipe system and / or wherein the measuring tube flange is fastened to the fastening section of the connecting element with fastening means.

[0021] The measuring tube flange is dimensioned differently in various designs. In a first variant, the outer diameter of the measuring tube flange is smaller than the inner diameter of the first tube. Accordingly, the measuring tube fits completely into the first tube and is not clamped in the area of ​​the flange connection, especially when the first and second tubes of the piping system are flanged together.

[0022] The measuring tube flange can be formed integrally with the measuring tube, which means that the measuring tube and measuring tube flange are formed from one workpiece or from one casting, or alternatively the measuring tube flange can be realized separately and then connected to the measuring tube.

[0023] If the outer diameter of the measuring tube flange is substantially equal to or smaller than the inner diameter of the first tube, then, in the inserted state, the measuring tube flange is fastened to the connecting element, and only the connecting element, and not the measuring tube flange, is clamped between the flanges of the first tube and the second tube.

[0024] In another variant, the outer diameter of the measuring tube flange is larger than the inner diameter of the first tube. According to this design, the measuring tube flange and the connecting element are clamped between the flanges of the first tube and the second tube when inserted.

[0025] According to the invention, various variants are provided for fastening the measuring tube flange to the connecting element.

[0026] In a first variant, the measuring tube flange is fastened to the connecting element using fastening means. These fastening means can be screws, for example. Accordingly, holes for the screws are then provided in both the measuring tube flange and the connecting element. If the connecting element has a circular fastening section, the fastening takes place in the area of ​​the fastening section. The fastening between the measuring tube and the connecting element can also be realized by means of a snap-in connection or an adhesive connection. If the fastening is realized by means of a snap-in connection, corresponding snap-in means, in particular snap-in lugs and corresponding snap-in recesses, are formed on the connecting element and the measuring tube flange. The fastening types described are not exhaustive, but merely exemplary.Different types of fastening can also be combined with each other.

[0027] In addition, a further variant provides that the fastening in the installed state of the measuring tube and the connecting element in the pipe system is realized by clamping between the first flange of the first pipe and the second flange of the second pipe of the pipe system.

[0028] A further preferred embodiment of the ultrasonic flowmeter is characterized in that the at least one ultrasonic transducer is cast into the measuring tube.

[0029] The measuring tube is particularly preferably made of a plastic, more particularly of epoxy resin. For example, the measuring tube is manufactured by injection molding.

[0030] According to an alternative embodiment, the measuring tube has at least one transducer pocket, wherein the at least one ultrasonic transducer is arranged in the at least one transducer pocket, in particular wherein the measuring tube is designed as a thin-walled tube such that the wall thickness of the measuring tube is less than the extent of the transducer pocket perpendicular to the longitudinal axis of the measuring tube and the transducer pocket extends into the outer space of the measuring tube.

[0031] Alternatively, the transducer pocket can also extend into the measuring tube wall, whereby the wall thickness of the measuring tube wall is greater than the extension of the transducer pocket perpendicular to the longitudinal axis of the measuring tube, so that the transducer pocket is arranged completely in the measuring tube wall.

[0032] According to a further preferred embodiment, the measuring tube has an inner cross-sectional area, wherein the shape and / or size of the inner cross-sectional area changes along the length of the measuring tube. For example, the measuring tube has at least one cross-sectional reduction in the direction of flow of the flowing medium. To minimize vortex formation, the transition between the first larger cross-section and the second smaller cross-section is formed by an inclined wall section of the measuring tube wall.

[0033] According to a further advantageous embodiment, the measuring tube has at least one enlarged cross-section in the direction of flow of the flowing medium. To minimize vortex formation, the transition between the smaller cross-section and the larger cross-section is formed by an inclined wall section of the measuring tube wall.

[0034] According to a further embodiment, the first tube has a recess in the region where the measuring tube is inserted, in which the measuring tube is arranged. According to this embodiment, the first tube and the measuring tube are matched to one another in such a way that the inner cross-sectional area of ​​the first tube and the second tube corresponds to the inner cross-sectional area of ​​the measuring tube, so that the flow cross-section is maintained throughout the entire length of the measuring arrangement.

[0035] According to a further advantageous embodiment of the ultrasonic flowmeter, the wall thickness of the measuring tube wall changes along the length of the measuring tube. For example, the wall thickness is greater in the region in which the at least one ultrasonic transducer is arranged than in the region in front of and behind it (viewed in the direction of flow).

[0036] Also described is a connecting element for realizing an electrical connection between an ultrasonic transducer and a control and evaluation unit for one of the previously described embodiments of an ultrasonic flowmeter according to the invention, wherein, in the state of the measuring tube inserted into the pipe system, the connecting element is clamped between the first flange of the first pipe and the second flange of the second pipe and realizes an electrical connection from the interior of the pipe system to the exterior of the pipe system, and wherein the connecting element is at least partially formed by a printed circuit board having at least one electrical line.

[0037] According to preferred embodiments, the electrical connecting element has one or more features of the embodiments described above, insofar as these embodiments relate to the specific design of the connecting element.

[0038] According to a further teaching of the present invention, the object set out at the outset is achieved by a measuring arrangement comprising one of the previously described embodiments of an ultrasonic flow meter according to the invention and at least a first tube with a first flange and a second tube with a second flange, wherein the measuring tube of the ultrasonic flow meter is inserted into the first tube and wherein at least the connecting element is clamped between the first flange of the first tube and the second flange of the second tube.

[0039] According to preferred embodiments, the measuring arrangement has one or more features of the embodiments described above, insofar as these embodiments relate to the specific design of the measuring arrangement.

[0040] In detail, there are numerous possibilities for designing and developing the ultrasonic flowmeter according to the invention, the electrical connecting element, and the measuring arrangement. Reference is made to the claims subordinate to the independent claims and to the description of preferred embodiments in conjunction with the drawing. The drawing shows: Fig. 1 an embodiment of a measuring tube and a circuit board Fig. 2 an embodiment of a built-in ultrasonic flow meter, Fig. 3 another embodiment of a built-in ultrasonic flow meter, Fig. 4 another embodiment of a built-in ultrasonic flow meter, Fig. 5 another embodiment of a built-in ultrasonic flow meter Fig. 6 different options for installing ultrasonic transducers in the measuring tube, Fig. 7 an embodiment of a measuring tube Fig. 8 an embodiment of a measuring tube and a pipe system, Fig. 9 another embodiment of a measuring tube and a pipe system and Fig. 10 another embodiment of a measuring tube and a pipe system.

[0041] Fig. 1 shows an embodiment of a measuring tube 2 and a connecting element 3 in the form of a circuit board 3a of an ultrasonic flow meter 1 according to the invention.

[0042] The measuring tube 2 is designed for insertion into a first pipe 4 of a pipe system at the location of a flange connection.

[0043] Ultrasonic transducers (not shown here) are arranged in or on the measuring tube 2. A connecting element 3 is provided to connect the ultrasonic transducers to the control and evaluation unit 5, which is located outside the pipe system when installed. During operation, this connecting element is also arranged in the area of ​​the flange connection between the first pipe 4 and the second pipe 6 of the pipe system.

[0044] During operation, the connecting element 3 shown is clamped between the flanges of the first 4 and the second pipe 6, whereby the connecting element 3 as a whole is fixed in the measuring arrangement.

[0045] The connecting element 3 has a circular fastening section 13 and a tab-like external contact area 14.

[0046] The connecting element 3 has bores 7 on the side facing the measuring tube, to which the measuring tube 2 can be screwed with the measuring tube flange 8, so that the measuring tube 2 is fixed to the connecting element 3 in the assembled state.

[0047] For contacting, the connecting element 3 further comprises contact elements 9, which are arranged in a circle around the recess of the connecting element.

[0048] The connecting element 3 has a plurality of contact elements 9 so that each ultrasonic transducer can be connected to a contact element 9.

[0049] With regard to the arrangement and contacting of ultrasonic transducers on or in the measuring tube 2, different possibilities are described below.

[0050] Fig. 2 shows an embodiment of a built-in ultrasonic flowmeter 1 and an embodiment of a measuring arrangement 16 according to the invention. The ultrasonic flowmeter 1 has a measuring tube 2 arranged in a pipe system with a plurality of ultrasonic transducers (not shown here), a connecting element 3 for contacting the ultrasonic transducers and a control and evaluation unit 5 arranged outside the pipe system.

[0051] The measuring tube 2 has a measuring tube flange 8. Bores 7 are provided in the measuring tube flange 8. The connecting element 3 has a recess whose size and shape essentially correspond to the inner cross-sectional area of ​​the measuring tube 2. In the area where the connecting element 3 rests against the measuring tube flange 8, the connecting element 3 also has bores 7, so that the measuring tube flange 8 can be connected to the connecting element 3 by a screw connection.

[0052] In the illustrated embodiment, the outer diameter of the measuring tube flange 8 is smaller than the inner diameter of the first tube 4 in which the measuring tube 2 is arranged. In the illustrated embodiment, the measuring tube 2 is thus arranged entirely within the first tube 4 and fixed by the connection to the connecting element 3.

[0053] The connecting element 3 is fixed in the measuring arrangement by being clamped between the first flange of the first pipe 4 and the second flange of the second pipe 6. Outside the pipe system, the connecting element 3 has a contact element 9 for external contacting of the connecting element 3.

[0054] The control and evaluation unit 5, which is also arranged outside the pipe system, is connected to the connecting element 3 via the contact element 9.

[0055] The printed circuit board 3a has internal conductor tracks which ensure an electrical connection between the inner contact elements 9 and the outer contact element 9.

[0056] To ensure clarity, the individual components shown are arranged slightly spaced from one another. During operation, the connecting element 3 is naturally clamped tightly between the flanges of the pipes 4 and 6. To ensure sufficient tightness, a sealing ring 15 is arranged between the connecting element 3 and the flanges of the first pipe 4 and the second pipe 6 in the illustrated embodiment. To improve clarity, the individual components of the embodiments shown below are also arranged at a distance.

[0057] Fig. 3 shows a further embodiment of a measuring arrangement 16 in which an ultrasonic flow meter 1 is arranged in a first pipe 4 of a pipe system.

[0058] In contrast to the Fig. In the embodiment shown in Figure 2, the measuring tube flange 8 is dimensioned such that the measuring tube flange 8 is also clamped between the first flange of the first tube 4 and the second flange of the second tube 6. According to the illustrated embodiment, both the measuring tube flange 8 and the connecting element 3 are clamped between the first flange of the first tube 4 and the second flange of the second tube 6.

[0059] As in Fig. In the embodiment shown in Figure 2, the measuring tube is connected to the connecting element via a screw connection. This screw connection can also be omitted, since the measuring tube 2 is additionally secured by the flange connection of the pipe system.

[0060] In the illustrated embodiment, the ultrasonic transducers are arranged in transducer pockets 10 of the measuring tube 2, with the transducer pockets 10 extending into the exterior of the measuring tube 2. Bores 7 are provided in the measuring tube flange 8, and contact elements 9 are provided on the connecting element 3, which are coordinated with one another in such a way that the electrical leads of the ultrasonic transducers are guided through the bores 7 in the measuring tube flange 8 and can thus contact the contact elements 9 of the connecting element.

[0061] Fig. Figure 4 shows a further embodiment of a measuring arrangement 16 comprising a pipe system, a measuring tube 2 with a measuring tube flange 8, and a connecting element 3. The measuring tube 2 has transducer pockets 10 in which the ultrasonic transducers (not shown here) are arranged. The measuring tube flange 8 is dimensioned such that, in the connected state, it is arranged between the first flange of the first tube 4 and the second flange of the second tube 6.

[0062] According to this embodiment, the measuring tube 2 is fixed by being clamped between the first flange of the first tube 4 and the second flange of the second tube 6. The measuring tube 2 is not additionally screwed to the connecting element 3.

[0063] The connecting element 3 has a recess which is larger than the inner cross-sectional area of ​​the measuring tube 1. The contact elements 9 for contacting the printed circuit board 3a are arranged on the inside of the recess of the connecting element 3 or the printed circuit board 3a according to the illustrated embodiment.

[0064] For contacting the ultrasonic transducers, the measuring tube flange 8 has holes 7 through which electrical lines are led to the circuit board 3a.

[0065] In Fig. 5 shows a further embodiment of an ultrasonic flow meter 1, wherein a measuring tube 2 is inserted into a pipe system together with a connecting element 3.

[0066] The measuring tube 2 has a measuring tube flange 8, which is dimensioned such that, when connected, it is clamped between the first flange of the first tube 4 and the second flange of the second tube 6. Furthermore, the measuring tube 2 has transducer pockets 10 in which ultrasonic transducers are arranged. The ultrasonic transducers as well as the transducer pockets 10 extend into the exterior of the measuring tube 2 and can therefore also be contacted via the exterior.

[0067] For this purpose, the connecting element 3 is arranged between the measuring tube flange 8 and the first flange of the tube 4. The recess of the connecting element 3 is therefore larger than the outer diameter of the measuring tube 2.

[0068] Both the measuring tube 2 and the connecting element 3 are secured by the first flange of the first pipe 4 of the pipe system and by the second flange of the second pipe 6 of the pipe system. Additionally, the connecting element 3 and the measuring tube flange 8 can be screwed together, provided appropriate holes are available.

[0069] Fig. Figure 6 shows possible arrangements of the ultrasonic transducers 11 in the measuring tube wall. The ultrasonic transducers 11 can be fully encapsulated or held in a transducer pocket with a positive and / or non-positive fit. According to the three illustrated arrangements of the ultrasonic transducers 11 in the measuring tube wall, the electrical cable for contacting the ultrasonic transducers 11 is also encapsulated, i.e., routed through the measuring tube wall.

[0070] The arrangement of the ultrasonic transducer 11 in the measuring tube wall has the advantage that there is no need for a large gap between the inner tube wall of the first tube 4 and the outer measuring tube wall of the measuring tube 2. If an acoustic and / or electrical insulation layer is present between the tube walls, the outer measuring tube wall can also be in contact with the coating of the inner tube wall of the first tube, or the coated outer measuring tube wall can also be in contact with the inner tube wall of the first tube.

[0071] Fig. Figure 7 shows an alternative arrangement of the ultrasonic transducers on the measuring tube. In the illustrated embodiment, the measuring tube 2 has transducer pockets 10 into which ultrasonic transducers and reflectors and / or other sensors can be inserted. The transducer pockets 10 extend into the exterior of the measuring tube 2. The measuring tube is designed as a thin-walled measuring tube such that the extent of the transducer pockets 10 perpendicular to the longitudinal axis of the measuring tube 2 is greater than the wall thickness of the measuring tube 2. The measuring tube 2 shown has the advantage that the large number of transducer pockets 10 allows the measuring tube to be used particularly flexibly.

[0072] Different measurement paths can be implemented, as can various combinations of ultrasonic transducers, reflectors, and other sensors, such as pressure sensors and / or temperature sensors. The transducer pockets 10, in which no ultrasonic transducer, reflector, or other sensor is located, are closed by end elements. The measuring tube shown can therefore be used in a variety of measurement situations.

[0073] Fig. Figure 8 shows an embodiment of a measuring tube 2 inserted into a pipe system and thus a further embodiment of a measuring arrangement 16 according to the invention. In the illustrated embodiment, the first tube 4 has a recess for receiving the measuring tube 2. In the region in which the measuring tube 2 is arranged, the wall thickness of the first tube 4 is reduced.

[0074] The inner measuring tube cross-sectional area essentially corresponds to the inner cross-sectional area of ​​the first tube 4, specifically in the region where the wall thickness is not reduced. As a result, in the illustrated embodiment, the flow cross-section is advantageously constant throughout the measuring arrangement, thereby minimizing the risk of vortex formation.

[0075] The ultrasonic transducers 11 and their electrical leads are arranged in the measuring tube wall. The electrical leads run through channels 12 in the measuring tube wall to the contact elements 9 of the circuit board 3a.

[0076] Fig. 9 shows a further embodiment of a measuring tube 2 which is inserted into a pipe system and thus a further embodiment of a measuring arrangement 16 according to the invention. In contrast to the Fig. In the embodiment shown in Figure 8, the inner measuring tube cross-section is tapered in some areas. The ultrasonic transducers 11 are arranged in the area of ​​the taper. The electrical leads of the ultrasonic transducers 11 run in channels to the contact elements of the circuit board 3. To prevent vortex formation in the flowing medium, inclined measuring tube walls are provided upstream and downstream of the taper in the flow direction.

[0077] Fig. Figure 10 shows another embodiment of a measuring tube 2 inserted into a pipe system and thus another embodiment of a measuring arrangement 16 according to the invention. The measuring tube 2 shown in this embodiment also has a taper, with the ultrasonic transducers 11 arranged in the region of the taper. The electrical leads of the ultrasonic transducers 11 run in channels 12 to the contact elements of the circuit board 3a.

[0078] The first tube 4 has no recess for accommodating the measuring tube 2, so that the flow cross-section is reduced by inserting the measuring tube 2 into the first tube 4. To prevent vortex formation, the inner measuring tube cross-section has a run-up slope in the area of ​​the measuring tube flange 8.

[0079] Overall, the illustrated embodiments show that the combination of a measuring tube and a circuit board that can be inserted into the flange connection of a pipe system can be adapted particularly flexibly to different measuring environments and used in these different environments. Reference symbol 1 ultrasonic flow meter 2 measuring tube 3 circuit board 4 first pipe 5 Control and evaluation unit 6 second pipe 7 Hole 8 Measuring tube flange 9 Contact element 10 converter bag 11 ultrasonic transducers 12 Channel in the measuring tube wall 13 Fastening section 14 External contact section 15 Sealing ring

Claims

[1] Ultrasonic flow meter (1) for determining the flow of a medium, with a measuring tube (2) for insertion into a first pipe (4) of a pipe system at the location of a flange connection, with at least one ultrasonic transducer (11) arranged in the measuring tube (2) for transmitting and / or receiving ultrasonic signals, with at least one control and evaluation unit (5) which, in the mounted state, is arranged outside the pipe system and with a connecting element (3) for realizing an electrical connection between the ultrasonic transducer (11) and the control and evaluation unit (5), wherein the connecting element (3) is clamped in the mounted state between a first flange of the first pipe (4) and a second flange of a second pipe (6) and realizes an electrical connection from the interior of the pipe system to the exterior of the pipe system and wherein the connecting element (3) is at least partially formed by a printed circuit board (3a) having at least one electrical line. [2] Ultrasonic flow meter (1) according to claim 1, characterized by that the connecting element (3) has at least one substantially circular fastening section (13), in particular for connection to the measuring tube (2). [3] Ultrasonic flow meter (1) according to claim 2, characterized by that the connecting element (3) has at least one contact element (9) in the fastening section (13) for contacting the at least one ultrasonic transducer (11). [4] Ultrasonic flow meter (1) according to claims 1 to 3, characterized bythat the connecting element (3) - in particular the annular fastening section (13), if present - extends into a sealing area of ​​the pipe system in the flange connection and at least partially realizes a seal for the pipe system in the area of ​​the flange connection, in particular that a recess for receiving an external sealing means, in particular a sealing ring (15), is introduced into the connecting element (3) and / or that an additional sealing means is applied to the connecting element (3). [5] Ultrasonic flow meter (1) according to one of claims 1 to 4, characterized by that the connecting element (3) has an external contact section (14) which, when inserted into the pipe system, extends into the exterior of the pipe system, in particular that the external contact section (14) is designed in the manner of a tab. [6] Ultrasonic flowmeter (1) according to one of claims 1 to 5, characterized by that the measuring tube (2) has a measuring tube flange (8) for fastening the measuring tube (2) in the pipe system, wherein the fastening in the installed state of the measuring tube (2) and the connecting element (3) is realized by means of clamping between the first flange of the first pipe (4) and the second flange of the second pipe (6) of the pipe system and / or wherein the measuring tube flange (8) is fastened to the fastening section (13) of the connecting element (3) by fastening means. [7] Ultrasonic flow meter (1) according to claim 6, characterized by that the outer diameter of the measuring tube flange (8) substantially corresponds to or is smaller than the inner diameter of the first tube (4), so that in the inserted state the measuring tube flange (8) is fastened to the circuit board (3a), and only the connecting element (3), and not the measuring tube flange (8), is clamped between the flanges of the first tube (4) and the second tube (6). [8] Ultrasonic flow meter (1) according to claim 6, characterized by that the outer diameter of the measuring tube flange (8) is larger than the inner diameter of the first tube (4), so that in the inserted state the measuring tube flange (8) and the connecting element (3) are clamped between the flanges of the first tube (4) and the second tube (6). [9] Ultrasonic flow meter (1) according to one of claims 1 to 8, characterized bythat the measuring tube (2) has at least one transducer pocket (10), wherein the at least one ultrasonic transducer (11) is arranged in the at least one transducer pocket (10), in particular wherein the measuring tube (2) is designed as a thin-walled tube, such that the wall thickness of the measuring tube (2) is less than the extent of the transducer pocket (10) perpendicular to the longitudinal axis of the measuring tube (2), wherein the transducer pocket (10) extends into the outer space of the measuring tube (2) or that the at least one ultrasonic transducer (11) is cast into the measuring tube (2), in particular wherein, in addition, the electrical supply lines of the ultrasonic transducer (11) are also cast into the measuring tube (2). [10] Ultrasonic flowmeter (1) according to one of claims 1 to 9, characterized by that the measuring tube (2) is made of a plastic or of epoxy resin, in particular wherein the measuring tube (2) is injection-molded. [11] Ultrasonic flowmeter (1) according to one of claims 1 to 10, characterized by that the measuring tube (2) has at least two transducer pockets (10) for receiving the at least one ultrasonic transducer (11) and at least one reflector and / or at least one further sensor, for example a temperature sensor or a pressure sensor. [12] Ultrasonic flow meter (1) according to claim 11, characterized by that the measuring tube (2) is designed as a thin-walled measuring tube such that the wall thickness of the measuring tube (2) is less than the extent of the transducer pockets (10) perpendicular to the longitudinal axis of the measuring tube (2), wherein the transducer pockets (10) preferably extend into the outer space of the measuring tube (2). [13] Ultrasonic flowmeter (1) according to one of claims 1 to 12, characterized bythat the measuring tube (2) has an inner cross-sectional area and that the shape and / or size of the inner cross-sectional area changes over the course of the measuring tube (2). [14] Ultrasonic flowmeter (1) according to one of claims 1 to 13, characterized by that the wall thickness of the measuring tube wall changes along the length of the measuring tube (2). [15] Measuring arrangement (16) comprising an ultrasonic flow meter (1) according to one of claims 1 to 14 and at least a first tube (4) with a first flange and a second tube (6) with a second flange, wherein the measuring tube (2) of the ultrasonic flow meter (1) is inserted into the first tube (4) and that at least the connecting element (3) is clamped between the first flange of the first tube (4) and the second flange of the second tube (6).

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