ULTRASONIC FLOW METER, USE OF AN ULTRASONIC FLOW METER IN A SHUT-OFF ORGAN AND SHUT-OFF ORGAN

Description

[0001] The invention relates to an ultrasonic flow meter with at least one measuring tube, with at least one first pair of ultrasonic transducers comprising a first ultrasonic transducer and a second ultrasonic transducer, and with at least one second pair of ultrasonic transducers comprising a third ultrasonic transducer and a fourth ultrasonic transducer, wherein each ultrasonic transducer is configured as an ultrasonic transmitter and / or as an ultrasonic receiver. wherein the first pair of ultrasonic transducers is arranged offset in the direction of flow on the measuring tube such that the respective transmitter emits an ultrasonic signal in the direction of flow or against the direction of flow during operation and that the receiver receives the ultrasonic signal emitted by the transmitter, wherein the path of the ultrasonic signal between the first ultrasonic transducer and the second ultrasonic transducer defines a first signal path, wherein the first signal path defines a first measuring plane, wherein the second pair of ultrasonic transducers is arranged offset in the direction of flow on the measuring tube such that the respective transmitter emits an ultrasonic signal in the direction of flow or against the direction of flow during operation and that the receiver receives the ultrasonic signal emitted by the transmitter,wherein the path of the ultrasound signal between the third ultrasound transducer and the fourth ultrasound transducer defines a second signal path, wherein the second signal path defines a second measurement plane, wherein the measuring tube has at least one measuring tube cross-sectional area and one measuring tube axis, and wherein the measuring tube has a first measuring tube half and a second measuring tube half.

[0002] Furthermore, the invention relates to the use of an ultrasonic flow meter in a shut-off device, wherein the shut-off device has a flow channel and a shut-off device arranged in the flow channel, wherein the shut-off device has a shut-off body receptacle and a shut-off body movable in the shut-off body receptacle, wherein by moving the shut-off body in the shut-off body receptacle the flow cross-section for the medium in the shut-off device and thus in the flow channel can be changed, wherein the flow channel has an inlet area upstream of the shut-off device in the direction of flow.

[0003] Furthermore, the invention also relates to a shut-off device with an ultrasonic flow meter, wherein the shut-off device has a flow channel and a locking device arranged in the flow channel, wherein the locking device has a locking body receptacle and a locking body movable in the locking body receptacle, wherein by moving the locking body in the locking body receptacle the flow cross-section for the medium in the locking device and thus in the flow channel can be changed, wherein the flow channel has an inlet area in the direction of flow upstream of the locking device.

[0004] Measuring the flow rate of a medium flowing through a measuring tube using an ultrasonic flowmeter is known from the prior art. Ultrasonic flowmeters typically comprise a measuring tube and at least two ultrasonic transducers configured as ultrasonic transmitters and / or ultrasonic receivers, which are spaced apart from each other in the direction of flow (axially with respect to the measuring tube axis). To measure the flow rate, an ultrasonic signal is emitted along the signal path between the ultrasonic transducers both in the direction of flow and against the direction of flow. Due to the tracking effect, the signals traveling along a signal path with and against the flow have different transit times. The flow velocity is determined from the difference in transit time, and the volumetric flow rate is calculated taking into account the cross-sectional area of ​​the measuring tube.

[0005] Ultrasonic flow meters are also known that have more than one pair of ultrasonic transducers, so that two or more signal paths can be evaluated to determine the flow rate.

[0006] For example, German patent application DE 10 2007 004 936 B4 discloses an ultrasonic flowmeter with at least two pairs of ultrasonic transducers, wherein the ultrasonic transducers of each pair are arranged offset from one another in the longitudinal direction of the measuring tube on a common half of the measuring tube, and the ultrasonic reflector assigned to the respective pair of ultrasonic transducers is arranged between the two ultrasonic transducers on the other half of the measuring tube in the longitudinal direction of the measuring tube, such that an ultrasonic signal emitted by one ultrasonic transducer of a pair of ultrasonic transducers travels along a V-shaped signal path via the ultrasonic reflector assigned to that pair of ultrasonic transducers to the other ultrasonic transducer of the pair.wherein the first ultrasound transducer pair and the second ultrasound reflector are arranged on one half of the circumference and the second ultrasound transducer pair and the first ultrasound reflector on the other half of the circumference. The ultrasound transducer pairs are arranged such that the measurement planes spanned by the individual signal paths are parallel to each other.

[0007] Furthermore, it is known from the publication DE 10 2013 218 827 A1 to provide ultrasonic flow meters for flow measurement on or in the housing of a shut-off device, so that the volume or mass flow can be controlled based on the measured flow rate.

[0008] Furthermore, documents US 2006 288 798 A1 and US 2018 321 067 A1 each disclose an ultrasonic flowmeter with a plurality of ultrasonic transducers, wherein two ultrasonic transducers define a measurement path between them, so that the medium can be measured in different areas to improve the accuracy of determining the velocity of a flowing medium.

[0009] Particularly in shut-off devices, but also in other applications, the problem often arises that bends or cross-sectional changes in the measuring tube cause irregularities in the flow profile, leading to inaccuracies in the flow measurement at the measuring point. Specifically, for example, eddies present in the flowing medium being measured generate radial and tangential velocity components that distort the measurement of the flowing medium's velocity. This is especially problematic when the measuring point is located shortly before, after, or along the course of such areas that cause a disturbance in the flow profile.

[0010] Based on the prior art described above, the object of the invention is therefore to provide an ultrasonic flow meter that allows for particularly reliable flow measurement even in critical application areas. Furthermore, the object of the invention is to provide the use of such a flow meter in a shut-off device and a corresponding shut-off device.

[0011] According to a first teaching of the present invention, the problem set out above is solved by an ultrasonic flowmeter mentioned at the outset in that the measuring tube has a change in the shape and / or size of the measuring tube cross-sectional area in the course of the first signal path and the second signal path, that the first ultrasound transducer is arranged on the first half of the measuring tube and that the third ultrasound transducer is arranged on the second half of the measuring tube, that the first pair of ultrasound transducers and the second pair of ultrasound transducers are arranged on the measuring tube in such a way that the first measuring plane and the second measuring plane are not aligned parallel to each other.

[0012] It was recognized that the arrangement of the ultrasound transducer pairs according to the invention allows a flowing medium to be measured particularly reliably even in areas where the shape and / or size of the measuring tube cross-section changes, causing turbulence that interferes with the flow measurement.

[0013] Radial or tangential velocity components that cause errors can be particularly advantageously filtered out by sending a first ultrasonic signal along the first signal path and a second ultrasonic signal along the second signal path into the medium from different directions, preferably at substantially the same but opposite angles with respect to the measuring tube axis. For this purpose, the first ultrasonic transducer is arranged on the first half of the measuring tube and the third ultrasonic transducer is arranged on the second half of the measuring tube.

[0014] The first half of the measuring tube and the second half of the measuring tube are each formed from a first and a second circumferential half extending in the longitudinal direction of the measuring tube.

[0015] Furthermore, the individual ultrasonic transducers are aligned such that the first measurement plane, defined by the first signal path, and the second measurement plane, defined by the second signal path, are not parallel to each other. This results in the distance between the first and second measurement planes decreasing at least section by section along the measuring tube axis, and / or increasing at least section by section along the measuring tube axis. According to the invention, the arrangement of the ultrasonic transducers is adapted to the changes in the measuring tube along the measuring section, preferably in such a way that, with respect to the flow profile during operation, the areas are captured where turbulence has only a minor effect and the determination of the velocity of a turbulent or laminar flow profile exhibits the lowest possible error.

[0016] According to a particularly preferred embodiment, the first signal path defines exactly a first measurement level and the second signal path defines exactly a second measurement level.

[0017] Advantageously, the first pair of ultrasonic transducers and the second pair of ultrasonic transducers are arranged within the same measuring tube section, thus ensuring a particularly space-saving arrangement.

[0018] Furthermore, the ultrasonic flow meter has a control and evaluation unit that determines the flow rate of a flowing medium based on at least two ultrasonic signals.

[0019] According to a further embodiment, the first pair of ultrasonic transducers and the second pair of ultrasonic transducers are arranged on the measuring tube in such a way that, in the course of the measuring path between the ultrasonic transducers, the distance of the first measuring plane to the measuring tube axis essentially corresponds to the distance of the second measuring plane to the measuring tube axis.

[0020] This means that, preferably at every point on the measuring tube axis, the distance of the first measuring plane to the measuring tube axis is essentially as large as the distance of the second measuring plane to the measuring tube axis.

[0021] According to the invention, the ultrasonic transducers are arranged such that the distance between the first measuring plane and the second measuring plane decreases at least section by section along the measuring tube axis. Furthermore, according to the invention, the first measuring plane and the second measuring plane do not intersect in the area of ​​the measuring section between the ultrasonic transducers.

[0022] According to a further embodiment, the ultrasonic transducers are arranged in such a way that the distance between the first measuring plane and the second measuring plane increases at least section by section along the measuring tube axis.

[0023] According to a further embodiment, the first signal path and the second signal path have at least one reflective surface.

[0024] The reflective surface(s) can be formed by reflective elements inserted into the measuring tube and / or by the measuring tube itself. Depending on the design of the signal paths, the reflective surface(s) can be at least partially recessed from the inner wall of the measuring tube and / or project into the interior of the measuring tube and / or be flush with the inner wall of the measuring tube.

[0025] According to the invention, the first signal path and the second signal path are essentially V-shaped.

[0026] Particularly preferably, the first and second pairs of ultrasonic transducers are arranged such that the first and second signal paths, for example in a top-down view of the measuring tube, form two crossed V-shaped signal paths, wherein the two signal paths or the measuring planes do not intersect or touch each other within the measuring section between the ultrasonic transducers. For this purpose, the first pair of ultrasonic transducers and the reflective surface of the second signal path are arranged on the first half of the measuring tube, and the second pair of ultrasonic transducers and the reflective surface of the first signal path are arranged on the second half of the measuring tube.

[0027] According to a further advantageous embodiment, the first pair of ultrasonic transducers and the second pair of ultrasonic transducers are arranged such that the first signal path and the second signal path measure the flowing medium at a distance r = 0.5R or r > 0.3R or r > 0.5R, where R is the respective radius of the measuring tube cross-section along the measuring path. According to one embodiment, the radius R can change along the measuring path.

[0028] According to a further development, the first pair of ultrasound transducers is arranged on the first half of the measuring tube, and the second pair of ultrasound transducers is arranged on the second half of the measuring tube. According to this configuration, the first and second signal paths can be V-shaped or each exhibit multiple reflections.

[0029] According to a further embodiment, the measuring tube has a reduction in cross-sectional area, i.e., a decrease in the measuring tube's cross-sectional area, along the first and second signal paths. Particularly preferably, the size of the measuring tube's cross-sectional area decreases by at least 10% and / or by at most 30% and / or by approximately 20% along the measuring section between the ultrasonic transducers.

[0030] Alternatively, the measuring tube can also have a cross-sectional expansion, i.e. an increase in the measuring tube cross-sectional area, in the course of the first signal path and the second signal path.

[0031] According to a further embodiment, the cross-sectional area of ​​the measuring tube in the region of the first and third ultrasonic transducers, or upstream of the first and third ultrasonic transducers, is essentially round, and the cross-sectional area of ​​the measuring tube in the region of the second and fourth ultrasonic transducers is essentially oval. Within the scope of the present invention, an oval shape is preferably understood to be any rounded convex shape that, in the broadest sense, resembles the shape of an egg.

[0032] According to one embodiment, the measuring tube cross-section has a height and a width. Particularly preferably, the height of the measuring tube cross-section decreases continuously along the measuring path between the ultrasonic transducers and / or the width of the measuring tube cross-section increases continuously along the measuring path between the ultrasonic transducers. Preferably, the decrease in height is greater than the increase in width.

[0033] Alternatively, the height or width of the measuring tube cross-section can remain essentially unchanged along the measuring path, while the other, non-constant parameter, width or height, increases or decreases. Alternatively, both the height and the width of the measuring tube cross-section can decrease along the measuring path.

[0034] The first and second signal paths preferably run in the range of 0.5R above and below the measuring tube axis, respectively, where R is the respective radius that changes along the measuring path, or where, in the case of an oval shape, R corresponds to half the height of the measuring tube cross-section. Alternatively, the first and second signal paths can also be arranged continuously at an equal distance from the measuring tube axis, where the distance is less than 0.5R or greater than 0.5R, and where R is the respective radius that changes along the measuring path, or where, in the case of an oval shape, R corresponds to half the height of the measuring tube cross-section.

[0035] According to a further embodiment, the measuring tube cross-sectional area has at least a first circular arc and a second circular arc, wherein the radius of the first circular arc and the second circular arc continuously increases along the measuring path between the ultrasonic transducers.

[0036] Preferably, the radius of the first circular arc increases faster than the radius of the second circular arc, so that the measuring tube cross-section flattens out in the area of ​​the first circular arc along the measuring distance.

[0037] According to a further embodiment, the second circular arc in the course of the measuring distance between the ultrasound transducers corresponds continuously to essentially a semicircle.

[0038] The ultrasonic transducers are preferably arranged on the measuring tube such that the first and second signal paths are not located, or not completely located, in the widening or flattening section of the measuring tube. In these sections, mass transport occurs perpendicular to the flow direction of the medium, which promotes turbulence formation. By avoiding these sections, the accuracy of determining the medium's velocity can be further improved during operation.

[0039] Basically, the change in the shape and / or size of the measuring tube cross-sectional area is adapted to the respective application of the ultrasonic flow meter.

[0040] According to a further advantageous embodiment, the first ultrasonic transducer of the first pair of ultrasonic transducers and the third ultrasonic transducer of the second pair are arranged on the circumference of a first cross-sectional area of ​​the measuring tube, and the second ultrasonic transducer of the first pair and the fourth ultrasonic transducer of the second pair are arranged on the circumference of a second cross-sectional area of ​​the measuring tube. This embodiment ensures that the flowing medium is detected within a section of the measuring tube, which is particularly advantageous when flow profiles change due to variations in the measuring tube.

[0041] Another embodiment of the flow meter is characterized by the fact that the measuring tube axis is curved, at least in sections. Accordingly, the measuring tube itself is also curved, at least in sections. This makes the flow meter particularly suitable for use, for example, in the inlet area of ​​a shut-off valve, where the flow pattern is typically optimized by appropriately shaping the inlet area.

[0042] According to a second teaching of the present invention, the aforementioned problem is solved by using an ultrasonic flow meter in a shut-off device as described above, in that the ultrasonic flow meter comprises at least one measuring tube, at least one first pair of ultrasonic transducers comprising a first ultrasonic transducer and a second ultrasonic transducer, and at least one second pair of ultrasonic transducers comprising a third ultrasonic transducer and a fourth ultrasonic transducer, wherein each ultrasonic transducer is configured as an ultrasonic transmitter and / or as an ultrasonic receiver. that the first pair of ultrasonic transducers is arranged offset on the measuring tube in the direction of flow such that each transmitter emits an ultrasonic signal in the direction of flow or against the direction of flow during operation, and that the receiver receives the ultrasonic signal emitted by the transmitter, wherein the path of the ultrasonic signal between the first ultrasonic transducer and the second ultrasonic transducer defines a first signal path, wherein the first signal path defines a first measuring plane, that the second pair of ultrasonic transducers is arranged offset on the measuring tube in the direction of flow such that each transmitter emits an ultrasonic signal in the direction of flow or against the direction of flow during operation, and that the receiver receives the ultrasonic signal emitted by the transmitter.wherein the path of the ultrasonic signal between the third and fourth ultrasonic transducers defines a second signal path, wherein the second signal path defines a second measurement plane, that the first signal path is substantially V-shaped and that the second signal path is substantially V-shaped, that the measuring tube of the ultrasonic flowmeter is formed at least as part of the flow channel, that the measuring tube has at least one measuring tube cross-sectional area and a measuring tube axis, that the measuring tube has a first measuring tube half and a second measuring tube half, that the measuring tube has a change in the shape and / or size of the measuring tube cross-sectional area along the first and second signal paths, that the first ultrasonic transducer is arranged on the first measuring tube half and that the third ultrasonic transducer is arranged on the second measuring tube half,that the first pair of ultrasonic transducers and the second pair of ultrasonic transducers are arranged on the measuring tube such that the first measuring plane and the second measuring plane are not aligned parallel to each other, and that the ultrasonic transducers are arranged such that the distance between the first measuring plane and the second measuring plane decreases at least section by section along the measuring tube axis, whereby the first measuring plane and the second measuring plane do not intersect in the area of ​​the measuring section between the ultrasonic transducers.

[0043] According to a particularly preferred design, the ultrasonic flow meter is designed according to one of the previously described configurations.

[0044] The inventive design of the ultrasonic flow meter ensures, particularly in different positions of the movable barrier element, which also have an effect on the shape of the flow cross-section in the flow channel, a reliable determination of the flow rate of a flowing medium, which can also improve the functionality of the shut-off device.

[0045] According to a third teaching of the present invention, the problem set out above is solved by a shut-off device with an ultrasonic flow meter as described above, in that the ultrasonic flow meter has at least one measuring tube, at least one first pair of ultrasonic transducers comprising a first ultrasonic transducer and a second ultrasonic transducer, and at least one second pair of ultrasonic transducers comprising a third ultrasonic transducer and a fourth ultrasonic transducer, wherein each ultrasonic transducer is configured as an ultrasonic transmitter and / or as an ultrasonic receiver. that the first pair of ultrasonic transducers is arranged offset on the measuring tube in the direction of flow such that each transmitter emits an ultrasonic signal in the direction of flow or against the direction of flow during operation, and that the receiver receives the ultrasonic signal emitted by the transmitter, wherein the path of the ultrasonic signal between the first ultrasonic transducer and the second ultrasonic transducer defines a first signal path, wherein the first signal path defines a first measuring plane, that the second pair of ultrasonic transducers is arranged offset on the measuring tube in the direction of flow such that each transmitter emits an ultrasonic signal in the direction of flow or against the direction of flow during operation, and that the receiver receives the ultrasonic signal emitted by the transmitter.wherein the path of the ultrasonic signal between the third and fourth ultrasonic transducers defines a second signal path, wherein the second signal path defines a second measurement plane, that the first signal path is substantially V-shaped and that the second signal path is substantially V-shaped, that the measuring tube of the ultrasonic flowmeter is formed at least as part of the flow channel, that the measuring tube has at least one measuring tube cross-sectional area and a measuring tube axis, that the measuring tube has a first measuring tube half and a second measuring tube half, that the measuring tube has a change in the shape and / or size of the measuring tube cross-sectional area along the first and second signal paths, that the first ultrasonic transducer is arranged on the first measuring tube half and that the third ultrasonic transducer is arranged on the second measuring tube half,that the first pair of ultrasonic transducers and the second pair of ultrasonic transducers are arranged on the measuring tube such that the first measuring plane and the second measuring plane are not aligned parallel to each other, and that the ultrasonic transducers are arranged such that the distance between the first measuring plane and the second measuring plane decreases at least section by section along the measuring tube axis, whereby the first measuring plane and the second measuring plane do not intersect in the area of ​​the measuring section between the ultrasonic transducers.

[0046] The ultrasonic flow meter is preferably designed according to one of the embodiments described above.

[0047] By designing the measuring tube as part of the flow channel, the inlet area of ​​the shut-off device can be optimized with regard to the separation of vortices that interfere with the flow measurement, and in combination with the arrangement of the ultrasonic transducers according to the invention, the accuracy of the flow measurement can be increased and thus the functionality of the shut-off device can also be improved.

[0048] In detail, there are numerous possibilities for designing and further developing the ultrasonic flow meter, its use, and the shut-off device according to the invention. Reference is made to both the claims subordinate to the independent claims and to the following description of preferred embodiments in conjunction with the drawing. The drawing shows Fig. 1 a first arrangement according to the invention of a first pair of ultrasonic transducers and a second pair of ultrasonic transducers, Fig. 2 a first embodiment of an ultrasonic flow meter according to the invention, an application and a shut-off device according to the invention, Fig. 3 the in Fig. 2 The illustrated embodiment is shown in side view, Fig. 4 is an embodiment of the signal path in an enlarged view, Fig. 5 is a measuring tube or flow channel in side view, and Fig. 6 shows the course of the measuring tube cross-sectional area of ​​the in Fig. 5 depicted measuring tube or flow channel.

[0049] In Fig. 1 Figure 1 shows a first arrangement of a first ultrasonic transducer pair 3, 4 comprising a first ultrasonic transducer 3 and a second ultrasonic transducer 4, and a second ultrasonic transducer pair 5, 6 comprising a third ultrasonic transducer 5 and a fourth ultrasonic transducer 6, wherein each ultrasonic transducer 3, 4, 5, 6 is configured as an ultrasonic transmitter and as an ultrasonic receiver. The illustrated arrangement is suitable for use in an ultrasonic flowmeter 1 according to the invention.

[0050] A V-shaped first signal path 7 is formed between the first ultrasound transducer 3 and the second ultrasound transducer 4, with the first signal path 7 defining a first measurement plane 19. Furthermore, the first signal path 7 runs over a reflection element with a reflective surface 9.

[0051] Between the third ultrasound transducer 5 and the fourth ultrasound transducer 6, the second V-shaped signal path 8 is formed, defining a second measurement plane 20. The second signal path 8 also runs over a reflection element with a reflective surface 10.

[0052] The measuring planes 19, 20 spanned by the signal paths 7 and 8 are aligned such that they are not parallel to each other. In the illustrated embodiment, the distance between the measuring planes 19, 20 decreases along the measuring path between the ultrasonic transducers 3 and 4 and 5 and 6, respectively.

[0053] Fig. 2 shows the application of the in Fig. 1 The arrangement of the first pair of ultrasonic transducers 3, 4 and the second pair of ultrasonic transducers 5, 6 shown in an ultrasonic flow meter 1, and the use of the ultrasonic flow meter 1 in a shut-off device 11.

[0054] The shut-off device 11 has a flow channel 12 and a locking device 13 arranged in the flow channel 12, wherein the locking device 13 has a locking body receptacle and a locking body movable in the locking body receptacle, which is not shown here, wherein by moving the locking body in the locking body receptacle the flow cross-section for the medium in the locking device 13 and thus in the flow channel 12 can be changed, wherein the flow channel 12 has an inlet area 15 in front of the locking device 13 in the direction of flow.

[0055] In the illustrated shut-off device 11, the flow channel 12, specifically the inlet area 15, is designed as the measuring tube 2 of the ultrasonic flow meter 1. The first pair of ultrasonic transducers 3, 4 and the second pair of ultrasonic transducers 5, 6 are located in the inlet area 15 on the flow channel 12 according to the Fig. 1 The described arrangement was installed.

[0056] Furthermore, the measuring tube 2 has a measuring tube cross-section 17, which changes in both shape and size along the measuring path between the pairs of ultrasonic transducers 3, 4, 5, 6. Specifically, the measuring tube cross-section 17 is essentially round, i.e., circular, in the area upstream of the first ultrasonic transducer 3 and the third ultrasonic transducer 5. Along the measuring path, the measuring tube cross-section 17 changes continuously. In the area downstream of the second ultrasonic transducer 4 and the fourth ultrasonic transducer 6, the measuring tube cross-section 17 is essentially oval, with the area of ​​the measuring tube cross-sectional area 17 decreasing along the measuring path. Specifically, the measuring tube cross-section 17 has two circular arcs whose radii increase at different rates along the measuring path (see Figure 1). Fig. 6 ), so that overall there is a flattening of the measuring tube cross-section as well as a widening of the measuring tube cross-sectional area 17.

[0057] In the illustrated embodiment, the measuring tube axis 18 and the measuring tube 2 are curved in the area of ​​the measuring section.

[0058] The flow channel 12 or the measuring tube 2 is designed in such a way that the shedding of vortices of the medium is minimized during operation.

[0059] Furthermore, the ultrasonic flow meter 1 shown has a control and evaluation unit 16 which determines the flow rate of a flowing medium based on at least two ultrasonic signals.

[0060] The Fig. 3 shows the in Fig. 2 The arrangement shown is in side view. This illustration clearly shows that the distance between the measuring planes 19 and 20, spanned by signal paths 7 and 8, decreases along the measuring path.

[0061] Fig. 4 The figure shows a further progression of the first signal path 7 and the second signal path 8, or the first measurement plane 19 and the second measurement plane 20. The illustration shows that the measurement planes 19 and 20, spanned by the two pairs of ultrasonic transducers, converge along the measurement path and are equidistant from the axis of the measuring tube 18. In the figure, R1 denotes the radius of the measuring tube cross-section 17 in the area upstream of the first ultrasonic transducer 3 and the third ultrasonic transducer 5, and R2 denotes the radius of the measuring tube cross-section 17, or half the height of the measuring tube cross-section 17 in the case of an oval shape, in the area just upstream of the second ultrasonic transducer 4 and the fourth ultrasonic transducer 6.

[0062] Fig. 5 Figure 1 shows an embodiment of a measuring tube 2 or a flow channel 12 upstream of the locking device 13, wherein different sections a to g are shown for comparison with Fig. 6 are identified. Ultrasonic transducers 3 and 5 are located approximately in the section between b and c during operation, and ultrasonic transducers 4 and 6 are located approximately in the section between e and f during operation.

[0063] Fig. 6 The diagram now shows the profile of the measuring tube cross-section, or the cross-section of the flow channel, between sections a to f. The illustration shows that the measuring tube cross-section 17 is initially circular and becomes continuously oval along the measuring section or flow channel. The measuring tube cross-section has a first upper circular arc 21 and a second lower circular arc 22, the radii of which increase continuously along the measuring section, with the radius of the first circular arc 21 increasing more rapidly than the radius of the second circular arc 22. The two circular arcs 21 and 22 are continuously connected by transition sections.Due to the flattening of the measuring tube cross-section, it has a height 23 and a width 24 along the measuring section, wherein the height 23 in the illustrated embodiment is defined by the distance between the vertices of the first circular arc 21 and the second circular arc, and wherein the width 24 of the measuring tube cross-section 17 is defined by the greatest distance between the transition sections between the first circular arc 21 and the second circular arc 22. This design has the advantage that vortex shedding in the area of ​​the measuring section can be reduced, which, in combination with the arrangement of the ultrasonic transducers 3, 4, 5, 6 according to the invention, improves the determination of the velocity of the medium.

[0064] As a result, all figures show exemplary embodiments of the invention, whereby in particular the inventive arrangement of the ultrasound transducer pairs allows the flow rate to be determined with particular reliability even in challenging situations where the flow profile is greatly disturbed due to a variation of the measuring tube in the area of ​​the measuring section. Bezugszeichen

[0065] 1 Ultrasonic flow meter 2 Measuring tube 3 Ultrasonic transducer 4 Ultrasonic transducer 5 Ultrasonic transducer 6 Ultrasonic transducer 7 First signal path 8 Second signal path 9 Reflection surface 10 Reflection surface 11 Shut-off device 12 Flow channel 13 Shut-off device 15 Inlet area 16 Control and evaluation unit 17 Measuring tube cross-section 18 Measuring tube axis 19 First measuring plane 20 Second measuring plane 21 First circular arc 22 Second circular arc 23 Height of the measuring tube cross-section 24 Width of the measuring tube cross-section

Claims

1. Ultrasonic flowmeter (1) with at least one measuring tube (2), with at least one first ultrasonic transducer pair (3, 4) comprising a first ultrasonic transducer (3) and a second ultrasonic transducer (4) and with at least one second ultrasonic transducer pair (5, 6) comprising a third ultrasonic transducer (5) and a fourth ultrasonic transducer (6), wherein each ultrasonic transducer (3, 4, 5, 6) is designed as an ultrasonic transmitter and / or as an ultrasonic receiver, wherein the first ultrasonic transducer pair (3, 4) is arranged on the measuring tube (2) offset as viewed in the direction of flow such that the respective transmitter transmits an ultrasonic signal in the direction of flow or against the direction of flow during operation, and that the receiver receives the ultrasonic signal transmitted by the transmitter, wherein the course of the ultrasonic signal between the first ultrasonic transducer (3) and the second ultrasonic transducer (4) defines a first signal path (7), wherein the first signal path (7) define a first measuring plane (19), wherein the second ultrasonic transducer pair (5, 6) is arranged on the measuring tube (2) offset as viewed in the direction of flow such that the respective transmitter transmits an ultrasonic signal in the direction of flow or against the direction of flow during operation, and that the receiver receives the ultrasonic signal transmitted by the transmitter, wherein the course of the ultrasonic signal between the third ultrasonic transducer (5) and the fourth ultrasonic transducer (6) defines a second signal path (8), wherein the second signal path (8) defines a second measuring plane (20), wherein the measuring tube (2) has at least one measuring tube cross-sectional area (17) and a measuring tube axis (18), and wherein the measuring tube (2) comprises a first half of the measuring tube and a second half of the measuring tube, wherein the measuring tube (2) exhibits a change in the shape and / or size of the measuring tube cross-sectional area (17) in the course of the first signal path (7) and the second signal path (8), wherein the first ultrasonic transducer (3) is arranged on the first half of the measuring tube and wherein the third ultrasonic transducer (5) is arranged on the second half of the measuring tube, wherein the first ultrasonic transducer pair (3, 4) and the second ultrasonic transducer pair (5, 6) are arranged on the measuring tube (2) such that the first measuring plane and the second measuring plane are not aligned parallel to one another, characterized in that the first signal path (7) is essentially V-shaped and that the second signal path (8) is essentially V-shaped, that the ultrasonic transducers (3, 4, 5, 6) are arranged such that the distance between the first measuring plane (19) and the second measuring plane (20) decreases at least in sections in the course of the measuring tube axis (18), wherein the first measurement plane and the second measurement plane do not intersect in the measurement section between the ultrasonic transducers.

2. Ultrasonic flowmeter (1) according to claim 1, characterized in that the first ultrasonic transducer pair (3, 4) and the second ultrasonic transducer pair (5, 6) are arranged on the measuring tube (2) such that, in the course of the measuring section between the ultrasonic transducers, the distance of the first measuring plane (19) from the measuring tube axis (18) essentially corresponds to the distance of the second measuring plane (20) from the measuring tube axis (18).

3. Ultrasonic flowmeter (1) according to claim 1 or 2, characterized in that the first signal path (7) has at least one reflecting surface (9, 10) and that the second signal path (8) has at least one reflecting surface (9, 10).

4. Ultrasonic flowmeter (1) according to any one of claims 1 to 3, characterized in that the first ultrasonic transducer pair (3, 4) is arranged on the first half of the measuring tube and that the second ultrasonic transducer pair (5, 6) is arranged on the second half of the measuring tube.

5. Ultrasonic flowmeter (1) according to any one of claims 1 to 4, characterized in that the measuring tube (2) has a cross-sectional reduction in the course of the first signal path (7) and the second signal path (8).

6. Ultrasonic flowmeter (1) according to any one of claims 1 to 4, characterized in that the measuring tube (2) has a cross-sectional expansion in the course of the first signal path (7) and the second signal path (8).

7. Ultrasonic flowmeter (1) according to any one of claims 1 to 6, characterized in that the measuring tube cross-sectional area (17) is essentially round in the region or upstream of the region of the first ultrasonic transducer (3) and the third ultrasonic transducer (5), and that the measuring tube cross-sectional area (17) is essentially oval in the region of the second ultrasonic transducer (4) and the fourth ultrasonic transducer (6).

8. Ultrasonic flowmeter (1) according to any one of claims 1 to 7, characterized in that the first ultrasonic transducer (3) of the first ultrasonic transducer pair and the third ultrasonic transducer (5) of the second ultrasonic transducer pair are arranged on the circumference of a first measuring tube cross-sectional area (17) and that the second ultrasonic transducer (4) of the first ultrasonic transducer pair and the fourth ultrasonic transducer (6) of the second ultrasonic transducer pair are arranged on the circumference of a second measuring tube cross-sectional area (17).

9. Ultrasonic flowmeter (1) according to any one of claims 1 to 8, characterized in that the measuring tube axis (18) is formed curved at least in sections.

10. Use of an ultrasonic flowmeter (1) in a shut-off device (11), wherein the shut-off device (11) has a flow channel (12) and a blocking device (13) arranged in the flow channel (12), wherein the blocking device (13) has a blocking body receptacle and a blocking body movable in the blocking body receptacle, wherein the flow cross-section for the medium in the blocking device (13) and thus in the flow channel (12) can be changed by moving the blocking body in the blocking body receptacle, wherein the flow channel (12) has an inlet region (15) upstream of the blocking device (13) as viewed in the direction of flow, wherein the ultrasonic flowmeter (1) has at least one measuring tube (2), at least one first ultrasonic transducer pair (3, 4) comprising a first ultrasonic transducer (3) and a second ultrasonic transducer (4) and at least one second ultrasonic transducer pair (5, 6) comprising a third ultrasonic transducer (5) and a fourth ultrasonic transducer (6), wherein each ultrasonic transducer (3, 4, 5, 6) is designed as an ultrasonic transmitter and / or as an ultrasonic receiver, that the first ultrasonic transducer pair (3, 4) is arranged on the measuring tube (2) offset as viewed in the direction of flow such that, during operation, the respective transmitter transmits an ultrasonic signal in the direction of flow or against the direction of flow, and that the receiver receives the ultrasonic signal transmitted by the transmitter, wherein the course of the ultrasonic signal between the first ultrasonic transducer (3) and the second ultrasonic transducer (4) defines a first signal path (7), wherein the first signal path (7) defines a first measuring plane (19), wherein the second ultrasonic transducer pair (5, 6) is arranged on the measuring tube (2) offset as viewed in the direction of flow such that, during operation, the respective transmitter transmits an ultrasonic signal in the direction of flow or against the direction of flow, and that the receiver receives the ultrasonic signal transmitted by the transmitter, wherein the course of the ultrasonic signal defines a second signal path (8) between the third ultrasonic transducer (5) and the fourth ultrasonic transducer (6), wherein the second signal path (8) defines a second measuring plane (20), wherein the measuring tube (2) of the ultrasonic flowmeter (1) is formed at least as part of the flow channel (12), wherein the measuring tube (2) has at least one measuring tube cross-sectional area (17) and a measuring tube axis (18), wherein the measuring tube (2) comprises a first half of the measuring tube and a second half of the measuring tube, wherein the measuring tube (2) exhibits a change in the shape and / or size of the measuring tube cross-sectional area (17) in the course of the first signal path (7) and the second signal path (8), wherein the first ultrasonic transducer (3) is arranged on the first half of the measuring tube and wherein the third ultrasonic transducer (5) is arranged on the second half of the measuring tube, wherein the first ultrasonic transducer pair (3, 4) and the second ultrasonic transducer pair (5, 6) are arranged on the measuring tube (2) such that the first measuring plane and the second measuring plane are not aligned parallel to one another, characterized in that the first signal path (7) is essentially V-shaped and that the second signal path (8) is essentially V-shaped, that the ultrasonic transducers are arranged such that the distance between the first measuring plane and the second measuring plane decreases at least in sections in the course of the measuring tube axis, wherein the first measurement plane and the second measurement plane do not intersect in the measurement section between the ultrasonic transducers.

11. Use according to claim 10, characterized in that the ultrasonic flowmeter (1) is designed according to any one of claims 1 to 9.

12. Shut-off device (11) with an ultrasonic flowmeter (1), wherein the shut-off device (11) has a flow channel (12) and a blocking device (13) arranged in the flow channel (12), wherein the blocking device (13) has a blocking body receptacle and a blocking body movable in the blocking body receptacle, wherein the flow cross-section for the medium in the blocking device (13) and thus in the flow channel (12) can be changed by moving the blocking body in the blocking body receptacle, wherein the flow channel (12) has an inlet region (15) upstream of the blocking device (13) as viewed in the direction of flow, characterized in that the ultrasonic flowmeter (1) is designed according to any one of claims 1 to 9, wherein the measuring tube (2) of the ultrasonic flowmeter (1) is designed at least as part of the flow channel (12).