FLOW MEASURING DEVICE

Description

[0001] The present invention relates to a flow measuring device for measuring a parameter, in particular for determining a flow rate from the parameter. The parameter is measured in a flow formed by a fluid, wherein the flow measuring device comprises a flow chamber with an inlet section and an outlet section, as well as a measuring section arranged between the inlet section and the outlet section. The measuring section defines a flow direction, and at least one ultrasonic device for emitting and / or receiving ultrasonic waves is arranged in the measuring section.

[0002] Such flow measuring devices are used, for example, in pipelines to determine the volume (i.e., the flow rate) of the fluid being transported through the pipeline. The fluid can be a liquid, such as water, or a gas, such as natural gas.

[0003] Due to the very high quantities transported, for example in pipelines, and the price of the transported fluid, it is of particular importance for such flow measuring devices to achieve high measurement accuracy.

[0004] The flow measurement devices described herein utilize the emission of ultrasonic waves through the fluid as their measuring principle. It is known to send the ultrasonic waves obliquely to the fluid's flow direction and to determine the transit time difference between the outbound and return paths along the same route. The fluid's flow velocity can then be determined from this transit time difference. The measurement effect is based on the phenomenon that an ultrasonic signal transmitted in the direction of flow has a shorter transit time than a signal transmitted against the flow direction. From the flow velocity, the volume flowing through the flow measurement device per unit time can ultimately be determined based on the known cross-sectional area of ​​the device.

[0005] In order to transmit the ultrasound signals obliquely to the fluid flow direction, the transducers for sending and receiving the ultrasound signals must also be arranged obliquely to the flow direction and, moreover, spaced apart from each other along the flow direction. This results in a relatively long flow measuring device, which is absolutely necessary.

[0006] Moreover, considerable effort is conventionally required to shape the fluid flow as homogeneously as possible. A homogeneous flow is usually necessary to achieve the required high measurement accuracy. Flow homogenization can be achieved, for example, by so-called "flow conditioners," which reduce or completely prevent turbulence or flows running at an angle to the flow direction. Such flow conditioners are typically integrated into the inlet of the flow meter, which increases the inlet length and also further increases the overall length required by the flow meter.

[0007] DE 11 2017 006 535 T5 describes a method and a device for measuring flow rate, wherein a fluid flowing linearly along the axial direction of a tangential flow generator arranged in a measuring tube passes over the tangential flow generator, generating a variation in direction to produce a fluid flowing in the circumferential direction. US 5,136,882 A relates to a device with a spiral tube, wherein the spiral tube is intended to keep the inner surface of the device clean. CN 102,322,906 A discloses a device with a flow deflection means and mirrors for deflecting an ultrasonic signal. US 10,845,224 B2 discloses a device for measuring the composition of multiphase fluids, e.g., mixtures of water, oil, and gas, wherein several sound paths pass through a central point of the device.

[0008] It is evident that conventional flow measuring devices have considerable installation lengths. Therefore, one of the objectives of the invention is to provide a flow measuring device of the type mentioned above that is more compact and yet still ensures high accuracy of the measurement result.

[0009] This problem is solved by a flow measuring device according to claim 1.

[0010] The flow measuring device according to the invention is characterized in that a flow deflection means (preferably at least in the inflow section) is arranged, which is configured to deflect the flow such that the flow in the measuring section runs at least partially obliquely to the transport direction. Furthermore, according to the invention, the ultrasonic device is configured to emit the ultrasonic waves through the fluid in several sound paths that are at least substantially perpendicular to the transport direction and / or to receive the ultrasonic waves from the fluid in several sound paths that are at least substantially perpendicular to the transport direction.

[0011] In comparison to known flow measuring devices, the invention takes a completely new approach. Instead of generating a flow that is as homogeneous and straight as possible through the measuring device and angling the transducers / sound paths relative to the flow direction, the invention generates a crossflow, which can then be detected with sound paths that are not angled.

[0012] The invention thus departs completely from the commonly used basic principle according to which the flow in the flow measuring device should be as homogeneous and straight as possible. Instead, according to the invention, a flow is intentionally generated that runs at least partially obliquely to the transport direction. This component running perpendicular to the transport direction can then be detected with the sound paths perpendicular to the transport direction or with the ultrasonic waves emitted along the sound paths (since the flow component running perpendicular to the transport direction can be detected with the sound paths). As explained in more detail below, the transport direction is, in particular, the direction in which the fluid is transported and / or in which the fluid would flow if the flow measuring device did not have any flow deflection means.

[0013] Contrary to previous assumptions, it has surprisingly been shown that very accurate measurement results can be achieved despite the non-linear and non-homogeneous flow. Because the sound paths run perpendicular to the direction of flow, the transducers used to generate the ultrasonic waves can also be positioned perpendicular to the flow direction and therefore no longer need to be spaced apart along the flow direction. This allows for a significant reduction in the length of the flow measurement device along the flow direction, something that was previously impossible with state-of-the-art flow measurement devices.

[0014] The invention thus completely departs from the hitherto unchallenged approach that the flow to be measured should be as uniform as possible and flow along the direction of transport, for which flow straighteners and long inlet sections, etc., are required, and that the flow to be measured should ideally only have axial components so that sufficiently accurate measurement results can be obtained via the previously used, angled measurement paths. According to the invention, the flow is intentionally given, for example, a swirl and thus, generally speaking, a non-axial component, which can then be measured using the perpendicular sound paths.

[0015] Moreover, it has been shown to be a further advantage that the flow measuring device according to the invention is very robust against pre-disturbances (i.e. inhomogeneities in the flow of the fluid), since the pre-disturbances are at least significantly reduced by the flow deflection means.

[0016] Further aspects of the invention are described below.

[0017] Under normal operating conditions, the fluid to be measured first flows through the flow section, is then directed from the flow section into the measuring section, and finally flows from the measuring section into the discharge section. The inlet and discharge sections can, for example, be connected by pipelines from which the fluid flows into the inlet section and into which the fluid from the discharge section is introduced.

[0018] The inlet and outlet sections may, for example, include connecting means for connecting the flow measuring device to the pipeline (e.g., a pipeline), particularly in the form of a flange with screw holes.

[0019] The inflow section, the measuring section and the outflow section together form the flow space, i.e. the area of ​​space in the measuring device through which the fluid flows.

[0020] The direction of flow is determined primarily by the shape of the measuring section, i.e., the shape of the flow chamber within the measuring section (but possibly also in conjunction with the inlet and outlet sections). The direction of flow is, in particular, the direction in which the fluid is transported and / or in which the fluid would flow if the flow measuring device did not have any flow deflectors. However, the measuring section can also be the entire flow chamber formed by a straight pipe. In this case, the direction of flow is then the longitudinal direction of the pipe. Accordingly, the direction of flow can be the direction in which the fluid primarily flows within the flow measuring device, for example, to move from the inlet section to the outlet section.The transport direction could therefore also be described as the main flow direction, i.e., the flow direction that would exist without the flow deflection devices.

[0021] The flow deflectors introduce a component into the fluid, or rather the fluid flow, that does not flow along the direction of transport, but at least partially obliquely to the direction of transport. The angle between the direction of transport and the deflected flow can be at least 25°, 30°, or 40°. As will be explained in more detail later, the flow deflector can, for example, have vanes arranged in the flow chamber that deflect the fluid laterally, thus introducing a kind of rotation or swirl into the flow. The component of the flow that does not flow solely along the direction of transport can then be measured using the ultrasonic device arranged according to the invention.

[0022] The deflected flow can describe an arc or a partial circle, especially when viewed along the direction of transport.

[0023] Basically, a flow is understood to be the directed movement of a fluid.

[0024] The ultrasound device comprises at least one ultrasound transmitter and one ultrasound receiver, which are arranged at opposite ends of one of the sound paths. According to the invention, units combining ultrasound transmitters and ultrasound receivers, i.e., so-called transducers, are arranged at opposite ends of a sound path. The ultrasound unit can accordingly comprise one or more pairs of transducers.

[0025] In particular, the transducers make it easy to measure the transit time of ultrasound waves through the sound path once in the forward direction and once in the return direction in order to determine a transit time difference, as will be explained in more detail later.

[0026] As mentioned, the sound path is at least substantially perpendicular to the direction of transport, so that two transducers belonging to a single sound path are arranged at the same position when viewed along the direction of transport. Spacing the transducers along the direction of transport is not necessary. According to the invention, several sound paths are formed, which are in particular parallel to each other and preferably lie in the same plane, with the direction of transport forming a normal to this plane. Using multiple sound paths allows for even more precise measurement results.

[0027] If flows are present in a sound path that run obliquely to the direction of transport and also have at least one component running along the sound path, the transit time through the sound path is shortened in one direction and lengthened in the opposite direction. The resulting actual measurement of the transit time difference accumulates over the forward and reverse signals of the ultrasound waves. According to the invention, it is not essential that the angle of the flow to the sound path be identical everywhere along the sound path. Surprisingly, it has been shown that, although the measurement signal of the ultrasound waves passes through different angles, the evaluation can be performed using a single angle (e.g., experimentally determined), and the flow velocity and thus the flow rate can still be determined very accurately.

[0028] The components used in prior art flow measuring devices can also be used for the flow measuring device according to the invention. For example, the same ultrasonic devices can be used, but installed in a different position according to the invention. The same electronics can also be used for evaluation, with only a minor change to the evaluation formula. Overall, the flow measuring device of the invention can be constructed, for example, from existing modular systems for flow measuring devices, making its manufacture simple and cost-effective. Furthermore, it is advantageous that the transducers of the ultrasonic device do not need to be installed at an angle, but rather vertically. This makes it possible, for example, to manufacture the measuring section using a conventional three-axis milling machine, since the bores for the transducers are perpendicular to the longitudinal direction.of the pipe used for the measuring section can be introduced.

[0029] According to the invention, the sound paths run at least substantially perpendicular to the direction of transport. This can particularly mean that the sound path(s) enclose an angle with the direction of transport which deviates by a maximum of 5°, preferably a maximum of 3°, more preferably a maximum of 1°, and more preferably a maximum of 0.5°, from a perpendicular to the direction of transport. Small deviations from the perpendicular still allow measurement according to the measuring principle underlying the invention. Preferably, however, the sound paths run as close as possible to / parallel to the perpendicular to the direction of transport.

[0030] Advantageous embodiments of the invention can be found in the description, the drawings and the dependent claims.

[0031] According to a first embodiment, at least one or all of the sound paths run eccentrically within the measuring section. In this context, "eccentric" can mean that the sound paths run off-center with respect to the cross-section of the measuring section. For example, if the measuring section is tubular, i.e., hollow cylindrical, then the sound path or paths do not pass through the center of the circle that forms the cross-section. In the case of a rectangular cross-section, the sound path or paths do not pass through the intersection of the diagonals, or, in the case of any cross-section, not through the centroid of the cross-section. In particular, the normal to the cross-section can run along the main direction of sound flow.

[0032] The off-center arrangement of the sound path or sound paths is advantageous because, with a sound path that runs through the center of the cross-section, the measurement effects on both sides of the center can cancel each other out, so that no meaningful time-of-flight difference measurement is possible there.

[0033] According to the invention, several parallel sound paths are provided. These multiple sound paths allow measurements to be taken at different positions within the cross-section of the measuring section. Furthermore, measurements can be performed simultaneously using multiple sound paths. Both of these aspects enable a higher overall accuracy in determining the flow rate. In particular, the accuracy increases with the square root of the number of sound paths as the number of sound paths increases.

[0034] According to a further embodiment, at least two sound paths are provided, which, in particular when projected onto the cross-section of the measuring section, are perpendicular to each other. Perpendicular sound paths allow for the use of larger transducers, such as those required for measurements in liquid media. In this way, the flow measuring device can be further miniaturized. The perpendicular sound paths can intersect or run separately.

[0035] According to a further embodiment, the flow deflection means has deflection surfaces arranged in the flow chamber. The deflection surfaces can, in particular, project into the flow chamber and / or define its boundaries. In particular, the flow deflection means is located at least partially in the inflow section.

[0036] The deflection surfaces can preferably be arranged transversely to the direction of transport. These deflection surfaces can, for example, be the surfaces of an internal thread in a pipeline. The surfaces of the internal thread can be excessively large. Alternatively or additionally, the deflection surfaces can comprise a plate with obliquely drilled holes, the holes deflecting the fluid transversely to the direction of transport.

[0037] Preferably, the deflecting surfaces exhibit an angle of at least 25°, 30°, or 40° to the direction of flow, at least in some areas. The angle can also be less than 60°, 70°, or 75°. By means of flow deflectors arranged at such an angle, the flow can exhibit a similar angle to the direction of flow after passing through the deflectors.

[0038] Preferably, all variants of the flow deflector mentioned herein are fixed flow deflectors. This means that the flow deflectors are permanently installed in the flow measuring device.

[0039] According to a further embodiment, the flow deflector comprises at least one swirl generator with multiple vanes, the vanes extending from a central connecting section to the wall of the flow chamber. The connecting section can be located, in particular, centrally within the cross-section of the flow chamber. The vanes can then extend radially from the connecting section to the wall bounding the flow chamber. The vanes are preferably inclined relative to the direction of flow and thus guide the flow in a direction transverse to the direction of flow, preferably (in the case of a circular cross-section) tangentially to the cross-section. The flow deflector can, for example, have two, three, four, five, six, seven, eight, nine, or ten vanes. Even more vanes can be provided, for example, at least 15, 18, or 20. Such a high number of vanes allows for improved flow guidance during deflection.A maximum of, for example, 30 or 40 wings can be provided.

[0040] According to another embodiment, the wings begin and end at the same position when viewed along the transport direction. Preferably, the wings each have a corresponding geometry. The wings can therefore all be identical. Furthermore, the wings can all have the same angle of attack, i.e., the same angle to the transport direction, the same profile, and / or the same material, etc. The wings can also have a tilt that changes along the transport direction. The angle specifications mentioned herein may refer in particular to the maximum tilt of each wing.

[0041] The vanes, or more generally the flow deflector, can cover more than 50%, preferably more than 70%, and particularly preferably more than 90% of the cross-sectional area along the transport direction. This area can be determined, in particular, by projecting the flow deflector onto a cross-sectional plane of the measuring section along the transport direction. This relatively high coverage ensures that virtually all fluid is deflected by the flow deflector, thus preventing, for example, turbulence in the flow.

[0042] According to a further embodiment, the flow deflector reduces the flow cross-section (at the position of the flow deflector) by less than 15%, preferably by less than 10% or less than 3%. The flow deflector can therefore be relatively thin and aerodynamically shaped, so that the flow cross-section is only minimally reduced. In practice, this can result in a very low pressure loss. The pressure loss coefficient ζ can thus be, for example, 1.5, which corresponds to a pressure loss of only about two 90° bends in a pipe. Despite the deflection of the fluid by the flow deflector, a very low pressure loss can therefore be achieved.

[0043] According to a further embodiment, the flow deflector is designed to deflect the flow such that the deflected flow is at least substantially axially symmetric about an axis extending along the transport direction. For example, in the aforementioned swirl generator with vanes, the connecting section can be arranged along this axis. Downstream of the flow deflector, the deflected flow can flow around this axis.

[0044] The swirl generator, and more generally the flow deflection device, can accordingly be designed to be rotationally symmetrical around a central axis of the flow chamber.

[0045] According to a further embodiment, a flow deflector is provided, preferably located in the outflow section. This flow deflector is designed to deflect the flow (coming from the measuring section) again so that the flow runs at least substantially parallel to the direction of transport, or is at least deflected in the direction of a flow parallel to the direction of transport. The flow deflector can thus ensure that a homogeneous and straight flow is present again after the outflow section. It is understood that the flow after the outflow section does not have to be parallel and straight in a mathematical sense. Small turbulences or minor cross currents may still be present.

[0046] According to a further embodiment, the flow deflection means corresponds to the flow diversion means, wherein the flow deflection means and the flow diversion means are preferably identical parts. Using identical parts reduces the production costs for the flow measuring device. Moreover, it has been shown that using identical flow diversion and flow deflection means downstream of the flow measuring device results in a relatively homogeneous and straight flow.

[0047] Preferably, the flow measuring device is designed to measure the parameter regardless of the flow direction. This means that the fluid can be introduced into the measuring device through both the inlet and outlet sections. For this purpose, the measuring device can be designed symmetrically, particularly with respect to the flow deflection and redirection means, and preferably also with respect to the shape of the flow chamber, so that the flow measuring device can be used bidirectionally. In other words, the flow measuring device is designed symmetrically, at least with respect to the components that come into contact with the fluid. This symmetry can be present, in particular, with respect to a plane in which the sound paths run.

[0048] In particular, the use of identical components for the flow deflection and flow redirection devices allows the device to be operated both in and against the direction of transport. The measuring device can therefore be installed in existing pipelines regardless of direction.

[0049] According to a further embodiment, the flow deflection means comprises at least one inlet opening obliquely or transversely to the transport direction into the flow space, through which a fluid can be introduced into the flow space.

[0050] Alternatively or in addition to the aforementioned deflection surfaces, the flow deflection device can also be based on a completely different principle, namely the introduction of a fluid transversely or obliquely to the direction of transport, thereby ultimately generating a flow in the measuring section that runs at least partially obliquely to the direction of transport. The position of the inlet is particularly off-center, and preferably tangential in the case of a round cross-section. More preferably, two inlets can be provided, located on opposite sides of the flow chamber. With multiple inlets, the inlets can be spaced apart from each other along the direction of transport.

[0051] The introduced fluid can either be the fluid to be measured, from which, for example, a portion has been diverted beforehand and which then returns to the flow chamber via the supply line. In the flow chamber, this diverted fluid can then mix with the (remaining) undiverted fluid. It would also be possible to divert all of the fluid to be measured and then introduce it back into the flow chamber, for example, via two supply lines. Alternatively or additionally, the fluid introduced via the supply line could also be an additional fluid, such as compressed air.

[0052] As a further or additional alternative for the design of the flow deflector, a spatial curvature, e.g., of the inlet section, can also be used. The flow deflector can accordingly comprise a single or a double curvature. The curvatures can each be 90° bends, which, for example, have a radius equal to the diameter of the inlet section. With a single or double curvature, a flow is also created that runs perpendicular to the direction of transport, which can then be measured again via the perpendicular sound paths.

[0053] All flow deflection devices mentioned herein can, in particular, generate a circular or circulating flow in the measuring section.

[0054] According to another embodiment, the inlet section, the measuring section, and the outlet section together form a single, preferably straight, pipe. Furthermore, the inlet section, the measuring section, and the outlet section together can have a length of less than 1.5 times, preferably less than 1.2 times, the pipe diameter. Due to the vertical arrangement of the sound paths, and thus also the vertical arrangement of the transducers, the flow measuring device can be designed to be particularly short and space-saving, as mentioned. Flow measuring devices are usually considerably longer, with a length of approximately three times the pipe diameter. Because of the significant shortening of the flow measuring device, a considerable space saving can be achieved, which can then be used effectively.For example, a flow conditioner can be placed upstream of the inflow section to homogenize the flow before the flow deflector.

[0055] The flow chamber can be tubular, especially with a circular cross-section.

[0056] The pipe forming the flow chamber is preferably rigid and immobile. The circular cross-section can be present almost everywhere in the flow chamber, with the exception, for example, of the connection points for the transducers.

[0057] According to another embodiment, the flow measuring device comprises an evaluation unit coupled to the ultrasonic device and designed to perform a transit-time difference measurement (using the ultrasonic device) and to determine the parameter. The evaluation unit can contain an effective angle, which specifies the angle between the deflected flow and the sound path(s). As mentioned above, the effective angle can, for example, be determined experimentally.

[0058] The measured parameter of the fluid can be the transit time of the ultrasonic waves along the sound path. Measuring the waves on both the outbound and return paths can reveal a difference in transit time. From this, the flow velocity of the fluid along the transport direction can first be determined. This can be done, in particular, using the formula... v p = L 2 ∗ tan α ⋅ 1 t AB − 1 t BA This will happen. vpthe flow velocity of the fluid along the transport direction, α the angle between the deflected fluid and the sound path, L the length of the sound path (i.e. the distance between two transducers of the same sound path), t AB the travel time in the forward direction of the sound path and t BA the travel time in the return direction of the sound path.

[0059] The flow velocity is then multiplied by the cross-sectional area (i.e., the cross-sectional area in the region of the sound path) to obtain the volume flowing through the flow measuring device per unit of time.

[0060] Furthermore, the invention relates to a method according to claim 15.

[0061] The descriptions of the flow measuring device according to the invention apply accordingly to the method according to the invention. This applies in particular with regard to advantages and embodiments. Furthermore, it is understood that all features and embodiments mentioned herein can be combined with one another, unless explicitly stated otherwise. This applies in particular to the combination of the different variants of the flow deflection means.

[0062] The invention is described below by way of example only, with reference to the drawings. The drawings show: Fig. 1 a schematic view of a flow measuring device; Fig. 2 a view of a flow deflector and a flow redirection device, seen along the transport direction; Fig. 3 a schematic perspective view of the flow deflector and the flow redirection device and the ultrasonic device; Fig. 4 the flow path through the flow measuring device; Fig. 5 a perspective view of the flow measuring device; Fig. 6 an embodiment of the flow deflector with inlet lines; and Fig. 7 a further embodiment of the flow deflector comprising a double bend.

[0063] Fig. 1Figure 10 schematically shows a flow measuring device 10. The flow measuring device 10 comprises an inlet section 12, a measuring section 14 adjoining the inlet section 12, and an outlet section 16 adjoining the measuring section 14. These sections are formed by a continuous pipe 18, which defines a flow chamber 20.

[0064] In measuring section 14, two ultrasound transducers A and B are provided, which transmit ultrasound waves to each other. The propagation path of the ultrasound waves defines a sound path 22.

[0065] During operation of the flow measuring device 10, a fluid F, for example natural gas, flows into the inlet section 12 along a transport direction 24. The fluid F is then passed through a (in Fig. 1The flow deflection means (not shown) is deflected so that the flow of fluid F is at least partially oblique to the transport direction 24. The oblique course is indicated by an angle α, which defines the angle between the sound path 22 and the course of the deflected flow.

[0066] Due to the fluid F flowing at an angle to the sound path 22, a time-of-flight difference can be measured using the transducers A, B, from which the volume flowing through the flow measuring device 10 per unit of time can be determined.

[0067] In drainage section 16 there is a (also in Fig. 1 A flow deflection device (not shown) is provided, which redirects the oblique course of the deflected flow back towards the transport direction 24. After being deflected by the flow deflection device, the fluid F leaves the flow measuring device 10.

[0068] Fig. 2Figure 1 shows a flow deflection device designed as a swirl generator 26. The swirl generator 26 comprises nine vanes 28, which are arranged rotationally symmetrically around a central connecting section 30. The vanes 28 originate from the connecting section 30 and extend to a wall 32 of the tube 18, and in particular merge into the wall 32.

[0069] In Fig. 2 Furthermore, a further swirl generator 34, which serves as a flow deflector, is partially visible behind the swirl generator 26. The two swirl generators 26 and 34 are identical components, with the additional swirl generator 34 being inserted into the pipe 18 in such a way as to reduce the crossflow of the deflected fluid F.

[0070] In the Figs. 3 and 4 The swirl generators 26 and 34 are shown in perspective and in a side view. As in Fig. 3As can be seen, four pairs of transducers A, B are arranged between the swirl generators 26, 34, each defining a sound path 22 between them. The transducers A, B are all arranged in a plane in the measuring section 14, to which the transport direction 24 forms a normal.

[0071] In Fig. 4 The developing flow of fluid F is shown. It can be seen that the homogeneously and straight-flowing fluid F is deflected by the swirl generator 26 in a direction oblique to the transport direction 24 and also flows in this deflected direction through the sound paths 22, thus enabling measurement. The further swirl generator 34 then reduces the transverse component of the flow, so that the flow with a reduced transverse component flows through the discharge section 16 and exits it in the same way.

[0072] Fig. 5Figure 1 shows a flow measuring device 10 from the outside in a perspective view. The flow measuring device 10 comprises two end faces, one of which is Fig. 5 visible. Boreholes 36 are provided in the end faces, which allow for screwing onto a (not shown) pipeline. The swirl generator 26 is also located directly in the plane formed by the end face, so that the swirl generator 26 is arranged at the inlet of the flow measuring device 10. The measuring section 14 is located in the center of the flow measuring device 10, wherein in Fig. 5 Electrical connections 38 for the transducers A, B can be seen, which protrude from a side wall of the flow measuring device 10.

[0073] A mounting flange 40 for evaluation electronics (not shown) is provided on the upper side of the flow measuring device 10.

[0074] The flow measuring device 10 is symmetrically designed so that the flow of the fluid F to be measured can be bidirectional. Accordingly, the additional swirl generator 34 can be flush in the Fig. 5 be arranged on the front side that is not visible.

[0075] The Figs. 6 and 7 Two further embodiments of the flow deflection device are shown. According to Fig. 6 The flow deflection device comprises two supply lines 42 that enter the pipe 18 tangentially. The supply lines 42 run at a right angle to the course of the pipe 18 before entering it. Fig. 6 This shows the course of the flow, whereby it can be seen that the flow in turn acquires a component perpendicular to the transport direction 24 (i.e. to the direction of travel of the pipe 18).

[0076] According to Fig. 7 The flow deflection device comprises a double curvature with two bends 44° each of 90°. Also in Fig. 7The resulting flow is shown again. It can be seen that, according to this embodiment as well, the flow deflection means deflects the flow in such a way that a kind of swirl or deflection occurs perpendicular to the transport direction 24. This deflection then allows a meaningful measurement of the transit time difference to be carried out with the sound paths 22, which are perpendicular to the transport direction 24.

[0077] As particularly in Fig. 5 As can be seen, the flow measuring device 10 can be designed very compactly, since only a very short pipe length is required for the transducers A and B within the flow measuring device 10. Despite the necessary deflection of the fluid F, practical experience has shown that very accurate measurements of the flow velocity, and thus of the volume flowing through the measuring device 10, are possible. Reference symbol list

[0078] 10 Flow measuring device 12 Inlet section 14 Measuring section 16 Outlet section 18 Pipe 20 Flow chamber 22 Sound path 24 Transport direction 26 Swirl generator 28 Vane 30 Connection section 32 Wall 34 Additional swirl generator 36 Borehole 38 Connection 40 Mounting flange 42 Supply line 44 Curve A, BTransducer FFluid αAngle

Claims

1. A flow measurement apparatus (10) for measuring a parameter, in particular for determining a flow rate, of a flow formed from a fluid (F), wherein the flow measurement apparatus (10) comprises a flow chamber (20) having an inflow section (12) and an outflow section (16) and a measurement section (14) arranged between the inflow section (12) and the outflow section (16), wherein the measurement section (14) defines a transport direction (24), wherein at least one ultrasonic device (A, B) for transmitting and / or receiving ultrasonic waves is arranged in the measurement section (14), and a flow deflection device (26, 42, 44) is preferably arranged at least in the inflow section (12) and is configured to deflect the flow such that the flow extends at least regionally obliquely to the transport direction (24) in the measurement section (14), characterized in that the ultrasonic device (A, B) is configured to transmit the ultrasonic waves through the fluid (F) in a plurality of sound paths (22) which are at least substantially perpendicular to the transport direction (24) and / or to receive the ultrasonic waves from the fluid (F) from a plurality of sound paths (22) which are at least substantially perpendicular to the transport direction (24), wherein a plurality of mutually parallel sound paths (22) are present, wherein transducers (A, B) are arranged at oppositely disposed ends of the sound paths.

2. A flow measurement apparatus (10) according to claim 1, wherein at least one of the sound paths (22) or all the sound paths (22) extends / extend off-center in the measurement section (14).

3. A flow measurement apparatus (10) according to claim 1 or 2, wherein at least two sound paths (22) extending perpendicular to one another are present.

4. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow deflection device (26, 42, 44) has deflection surfaces (28) arranged in the flow chamber (20).

5. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow deflection device has at least one swirl generator (26) comprising a plurality of blades (28) which extend from a central connection section (30) toward a wall of the flow chamber (20).

6. A flow measurement apparatus (10) according to claim 5, wherein the blades (28) start at the same position and end at the same position, viewed along the transport direction (24), wherein the blades (28) preferably each have a corresponding geometry.

7. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow deflection device (26, 42, 44) reduces the flow cross-section at its position by less than 15%, preferably by less than 10%.

8. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow deflection device (26, 42, 44) is configured to deflect the flow such that the deflected flow is axially symmetrical about an axis extending along the transport direction (24).

9. A flow measurement apparatus (10) according to any one of the preceding claims, wherein a flow return device (34) is preferably arranged in the outflow section (16) and is configured to deflect the deflected flow again such that the flow extends parallel to the transport direction (24).

10. A flow measurement apparatus (10) according to claim 9, wherein the flow return device (34) corresponds to the flow deflection device (26, 42, 44), wherein the flow return device (34) and the flow deflection device (26, 42, 44) are preferably identical parts.

11. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow measurement apparatus (10) is symmetrical at least with respect to the component that comes into contact with the fluid (F).

12. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow deflection device comprises at least one supply line (42) which opens into the flow chamber (20) obliquely or transversely to the transport direction (24) and through which a fluid (F) can be introduced into the flow chamber (20).

13. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the inflow section (12), the measurement section (14) and the outflow section (16) together form a pipe (18), in particular a straight pipe, and together have a length of less than 1.5 times, preferably of less than 1.2 times, the pipe diameter.

14. A flow measurement apparatus (10) according to any one of the preceding claims, wherein the flow measurement apparatus (10) comprises an evaluation unit which is coupled to the ultrasonic device (A, B) and which is configured to carry out a transit time difference measurement and to determine the parameter.

15. A method for measuring a parameter, in particular for determining a flow rate, of a flow formed from a fluid (F), wherein the fluid (F) flows in a transport direction (24), and the flow is deflected by means of a flow deflection device (26, 42, 44) such that the flow extends at least regionally obliquely to the transport direction (24) in a measurement section (14), characterized in that ultrasonic waves are transmitted through the fluid (F) in a plurality of sound paths (22) which are at least substantially perpendicular to the transport direction (24) and / or are received from the fluid (F) from a plurality of sound paths (22) which are at least substantially perpendicular to the transport direction (24), wherein a plurality of mutually parallel sound paths (22) are present, wherein transducers (A, B) are arranged at oppositely disposed ends of the sound paths.