Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
  • G01F1/662—Constructional details
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
  • G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters

Definitions

• Ultrasonic flow meters on the basis of at least two ultrasonic transducers are known from the prior art which are arranged offset in a flow tube in the direction of flow and send ultrasound signals to each other via at least one reflection surface. Examples of such ultrasonic sensors are in
• Measurement arrangements are known from the prior art, in which a reflector can be integrated in a pipe wall or is attached to a sensor module, which, together with the ultrasonic transducers and electronics, results in a kind of plug-in sensor.
• a reflector can be integrated in a pipe wall or is attached to a sensor module, which, together with the ultrasonic transducers and electronics, results in a kind of plug-in sensor.
• DE 10 2004 061 404 A1 Likewise, a plurality of mutually non-parallel reflecting surfaces can be used to detect a larger proportion of the flow through the resulting ultrasonic path.
• DE 43 36 370 C1 In this regard, reference may be made, for example, to DE 43 36 370 C1.
• DE 10 2006 041 530 A1 proposes a tube-shaped shielding of an ultrasonic path with respect to a flowing medium.
• the tubular shield is arranged such that in the rich one of the two ultrasonic transducers a tube is aligned so that a part of the transmission path of the ultrasonic wave is guided in this tube.
• the tube is thereby completed by one of the ultrasonic transducers, and the ultrasonic running distance within the tube is thus not part of a flow-through measuring section.
• DE 10 2006 023 479 A1 proposes a curved reflecting surface in which the sound is focused toward the other ultrasonic transducer and thus compensating for the waving of this ultrasonic wave. This is to be done in such a way that blasted beam portions reach a differently inclined reflector section and, due to this changed inclination, are still directed to the same or a similar reception point.
• the reflection surface described in DE 10 2006 023 479 A1 is fastened in a flow tube or on a sensor module, which also accommodates the ultrasonic transducers.
• a similar arrangement is also described in DE 10 2004 061 404 A1.
• some reflection surfaces with convex curvatures are also known.
• the ultrasound sensors known from the prior art have a number of technical challenges. These result in particular from the fact that different portions of the ultrasonic signals are transmitted in different ways at different flow velocities of the fluid medium.
• the method described in DE 10 2006 023 479 A1 is based on focusing and at the same time compensating for a drift of the ultrasonic waves.
• this compensation is difficult in practice, since usually different degrees of turbulence and velocity profiles are formed in the flow tube, depending on the flow rate, so that true compensation of the drift is only incompletely possible.
• the received signal even with a complete compensation depending on the flow rate ultrasonic components from different emission and detection angles, which always have slightly different transfer functions in conventional ultrasonic transducers.
• the ultrasonic flow sensor serves to detect a flow of a fluid medium in a flow tube.
• the ultrasonic sensor can be used, for example, in an ultrasonic air mass meter (ultrasonic flow meter, ultrasonic flow meter, UFM), for example in the motor vehicle sector or in other areas of technology, the natural sciences or medical technology.
• the fluid medium may be, for example, a liquid or a gas, for example
• the flow pipe can be, for example, a flow pipe of an air intake and / or an exhaust gas tract of an internal combustion engine.
• the ultrasonic flow sensor comprises at least a first ultrasonic transducer and at least one second ultrasonic transducer and at least one waveguide, wherein the waveguide is configured to ultrasonic waves between the at least one first ultrasonic transducer and the at least one second ultrasonic transducer (or vice versa, what this is to be implied) by Reflection on the walls of the waveguide, preferably at least partially by multiple reflection, to conduct.
• the waveguide is designed to be flowed through by the fluid medium.
• a hollow conductor is generally understood to mean an at least partially closed, tubular section or channel which has at least one reflection surface on which the reflections, preferably the multiple reflections, can take place.
• the waveguide can also be referred to as a channel-like reflection and / or guide device or configured.
• the waveguide can in particular be wholly or partly channel-shaped.
• a multiple reflection is to be understood as meaning a reflection in which a predominant proportion of the signals transmitted between the ultrasonic transducers
• Sound energy propagation paths follows, in which the ultrasonic waves are reflected at least twice, preferably at least three times and more preferably at least four times on at least one, preferably at least two reflecting surfaces of the waveguide.
• the ultrasonic waves are reflected at least twice, preferably at least three times and more preferably at least four times on at least one, preferably at least two reflecting surfaces of the waveguide.
• the sound components transmitted via reflection in particular multiple reflection, it is also possible to transmit sound components of the ultrasonic waves without
• Reflection are transmitted without reflected on the at least one reflection surface to become.
• a corresponding ultrasonic path, in which no reflection takes place, is correspondingly assigned a number of zero reflections.
• the ultrasonic flow sensor according to the invention is set up such that the ultrasonic waves between the first ultrasonic transducer and the second ultrasonic transducer can propagate on at least two ultrasonic paths.
• an ultrasound path is understood to be a geometric connection between the first ultrasound transducer and the second ultrasound transducer or a group of such connections, which have a common number of reflections at the at least one reflection surface and along which at least a portion of the ultrasound can propagate.
• ultrasonic paths there may be provided two, three, four or more ultrasonic paths, each having different reflections. At least two of these different ultrasound paths, preferably three, four or more or all of these different ultrasound paths should be substantially equal in terms of their contribution to the transmission of the sound energy between the ultrasound transducers. This means that sound energies of the ultrasonic waves transmitted on the at least two different ultrasound paths do not differ by more than a factor of 100, preferably by not more than a factor of 25 and more preferably not more than a factor of 4. If more than two different ultrasound paths are provided Thus, this condition may apply to at least two of these ultrasound paths, to more than two of these ultrasound paths, or even to all of these different ultrasound paths, in pairs. This condition generally ensures that in the ultrasonic flow sensor transmission of sound energy exceeds more than one
• Ultrasound can be done, the different ultrasonic paths essentially are equal.
• the ultrasound flow sensor can therefore be set up in particular such that different ultrasound paths are combined with different numbers of reflections, are at least partially equal in terms of their transmission and can contribute substantially equality to a signal formation of the ultrasound flow sensor.
• the ultrasound transducer is preferably to be set up in such a way that the different ultrasound paths are not merely subordinate ultrasound paths, but preferably a substantial proportion of the total sound energy is to be transmitted via these at least two different ultrasound paths or via at least two or more of these different ultrasound paths ,
• the sound energies of the ultrasonic waves transmitted via the at least two different ultrasound paths should together amount to at least 50%, preferably at least 60% or even at least 70% of an entire sound energy transmitted between the first ultrasound transducer and the second ultrasound transducer. This ensures that the collection effect described above does not only relate to subordinate ultrasound paths, but that the essential ultrasound paths are recorded with different numbers of reflections.
• At least two different ultrasound paths may exist, with a number of n1 reflections occurring at a first ultrasound path and a number n2 reflections at a second ultrasound path, and a number at n3 reflections at a third ultrasound path, etc.
• n1, n2 and optional n3, n4, etc. various non-negative integers, d. H. n1, n2, etc. are selected from the set ⁇ 0, 1, 2, 3, ... ⁇ and n1 n2, etc.
• Ultrasonic components preferably add up to at least 50% of the sound energy.
• the different ultrasound paths may be the main ultrasound paths, ie the ultrasound paths via which the strongest ultrasound components are transmitted.
• the ultrasound transducers may be configured to emit and / or detect wave packets substantially within an angular range of main sound lobes.
• an embodiment is to be understood in which at least 90% of the sound energy is emitted within the angular range of the main sound lobes, preferably more than 95%
• the ultrasonic flow sensor is preferably set up such that sound components within the main sound lobes differ depending on an emission angle
• the waveguide is preferably set up in such a way that the sound components of one of the ultrasound transducers are directed to the respective other of the ultrasound transducers and vice versa, whereby the sound components which differ with regard to the emission angle and the transfer function are preferably detected.
• the first ultrasonic transducer and the second ultrasonic transducer can be arranged substantially symmetrically to the waveguide. This means that preferably the propagation distances of the ultrasonic signals, apart from the flow of the fluid medium, do not differ or only insignificantly in an emission direction from the first ultrasound transducer to the second ultrasound transducer and vice versa.
• DE 10 2006 041 530 A1 discloses tubular shielding of an ultrasound path, which is deliberately chosen asymmetrically, so that no reflections that may possibly occur in this tube do not form a similar integration over the sidelobes or eccentric
• the waveguide may, in particular, comprise at least one channel section, which is aligned substantially parallel to a main flow direction of the fluid medium.
• a main direction of flow is to be understood as meaning a local preferred direction of the main mass or volume transport of the fluid medium at the location of the ultrasound sensor, whereby, for example, local vortices or local deviations can be neglected.
• a slight deviation from a perfect parallelism can also be substantially parallel be understood preferably a deviation of not more than 20 °, in particular not more than 10 ° or even not more than 5 °.
• the coupling of the ultrasonic waves in the waveguide can in principle be parallel or oblique to an axis of the waveguide. If the coupling is oblique to an axis of the waveguide, it is particularly preferred if the waveguide comprises at least two lateral openings for coupling ultrasonic waves in the channel section obliquely to the axis of the waveguide. These openings may include, for example, round, polygonal or basically any opening cross-sections or not completely enclosed by the material of the waveguide openings, so for example milled or recesses in walls of the waveguide. Furthermore, the openings may also comprise one or more supports which, for example, simplify mounting of the ultrasonic transducers relative to the openings.
• the waveguide may further comprise in the region of the openings coupling elements for deflecting ultrasonic waves, in particular curved coupling surfaces.
• the waveguide may in principle comprise one or more reflection surfaces. These reflection surfaces can be configured straight or curved.
• the waveguide may in particular comprise at least one curved reflection surface.
• reflection, such as multiple reflection, of the coupled ultrasonic waves takes place in the waveguide.
• the majority of the coupled into the waveguide ultrasonic waves is reflected in the waveguide, but also shares without reflection can remain.
• the ultrasonic flow sensor is set up such that ultrasound waves coupled into the waveguide are reflected on at least one of the possible ultrasound paths at least 3 times, and preferably at least 4 times or even at least 5 times or more, for example at least 10 times, at the at least one reflection surface.
• the ultrasonic flow sensor may in particular be set up such that the
• the ultrasonic flow sensor may in particular be configured such that a first part of the fluid medium flows through the waveguide and at least a second part of the fluid medium flows outside of the waveguide.
• This arrangement has the particular advantage that the waveguide in the region of the ultrasonic flow sensor does not have to be configured at least completely identical to the flow tube.
• the geometry of the ultrasonic flow sensor, the waveguide and / or the at least one reflection surface can be selected at least largely independently of the geometry and / or the dimension of the flow tube. This is not the case, for example, in the arrangements known from DE 43 36 370 C1 or DE 40 10 148 A1, for in these the flow tube itself is used as a reflector.
• the ultrasonic flow sensor can be used, for example, in different geometries on flow tubes.
• flow tubes with diameters of at least 600 mm can be used.
• the flow tube may have a circular, a round, a polygonal or basically any cross-section.
• the ultrasonic flow sensor can be wholly or partially configured as a plug-in sensor, ie as a component which can be inserted into the flow tube.
• the insertability can be made reversible, so that the plug-in sensor is also removed from the flow tube again.
• the plug-in sensor can be connected, for example, with the flow tube by a non-positive and / or positive and / or a material connection.
• the ultrasonic flow sensor may also be permanently connected to the flow tube.
• the waveguide may, as stated above, itself comprise one or more reflection surfaces, which may be configured straight or curved.
• the waveguide may, in particular, have a cross section which is selected from the following cross sections: a polygonal cross section, in particular a triangular or rectangular cross section; a U-section; a trough-shaped cross section; a channel-shaped cross-section.
• a polygonal cross section in particular a triangular or rectangular cross section
• U-section a trough-shaped cross section
• a channel-shaped cross-section Various embodiments and embodiments of these cross sections will be described in more detail below.
• the waveguide is preferably configured at least partially different from the flow tube, that is, at least not completely identical to the component with the flow tube.
• at least one reflection surface may be different from a wall of the flow tube.
• the waveguide can also be configured at least partially identically with the flow tube, so that, for example, example, a wall of the flow tube is used as a wall surface, for example as a reflection surface of the waveguide.
• the ultrasonic transducers can be arranged, in particular, in a measuring section of the flow tube which acts as a waveguide or which surrounds the waveguide. In particular, this may be a straight measuring section.
• the measuring section may be part of the main flow pipe or may also be arranged wholly or partly in a bypass. In this case, the flow of the fluid medium can be coupled laterally into the measuring section, for example with inlets and outlets arranged on the same side of the measuring section or with inlets and outlets arranged on opposite sides.
• the waveguide can in particular be arranged wholly or partly in a main flow tube.
• the waveguide can also be accommodated at least partially in a bypass of the flow tube, ie a distance within which a portion of the fluid flowing through the flow tube is discharged from the main flow tube and passed through at least one secondary passage.
• a measuring section can be arranged in this secondary channel, ie the bypass.
• the proposed ultrasonic flow sensor has a number of advantages over known ultrasonic flow sensors and measuring principles.
• the present invention in contrast to the prior art, does not necessarily implement a direct focus or targeted compensation of drifts, but it will be already without flow aware of the different
• FIG. 1 shows an example of an ultrasonic wave packet for a transit time measurement
• FIG. 2 shows a known ultrasonic flow sensor with a curved reflection surface
• FIG. 4 shows a first exemplary embodiment of the ultrasonic flow sensor according to the invention
• FIG. 5 is a perspective view of a waveguide
• FIG. 6 shows a second exemplary embodiment of an ultrasonic flow sensor according to the invention
• FIG. 7 shows an exemplary embodiment of an ultrasonic flow sensor designed as a plug-in sensor
• FIG. 8 shows an ultrasonic flow sensor with a direct coupling of the ultrasonic signals into the waveguide
• FIGS. 12A and 12B show various views of the trough-shaped waveguide in FIG.
• FIG. 16 shows an exemplary embodiment of an ultrasonic flow sensor in one embodiment
• FIG. 1 shows a typical ultrasound wave packet, as can be used for transit time measurement.
• the representation is taken from DE 10 2004 013 249 A1, so that reference can be made to this document for possible details of the ultrasonic wave packet.
• Due to the limited bandwidth of conventional ultrasonic transducers the transient response of the ultrasonic wave packet extends over several ultrasonic oscillations, so that there is generally no natural, unambiguous reception time. Rather, a feature must first be defined, which is then to be detected as the time of reception. In order to achieve a high time resolution, the information content of the slowly rising envelope of the ultrasound signal according to FIG. 1 is generally insufficient for this purpose. Instead, z. B. a specific zero crossing of the ultrasonic signal can be evaluated with the corresponding larger slope.
• a zero crossing time t 0 can be used after a threshold value SW has been exceeded.
• the threshold value can be tracked from one to the next measurement.
• the runtime can also be detected by other methods, which, however, should ultimately always be based on the recognition of features in the received signal history and thus react more or less sensitively to changes in the signal form.
• Such changes can be at least partially compensated by the application of tion of control methods in which at least slow changes in the shape of the received signal waveform are detected and stored and taken into account in the detection of features in the received signals of subsequent measurements.
• a fundamental difficulty is usually that an initial value must first be defined for such updates. If, for example, the amplitude of the received signals and thus also the tracked trigger threshold in FIG. 1 changes by more than the amplitude difference between two successive ultrasonic waves within the transient flank, a correct value is generally no longer reached after renewed switching on of the ultrasound flow sensor.
• the ultrasonic flow sensor is switched off and then switched on again when the medium is at rest. In this case, the tracking would still be at the now incorrect value for high flow rates.
• the ultrasonic flow sensor should therefore advantageously be designed such that the flow shifts the entire signal as a whole and its shape remains stable.
• a possible cause of changes in the waveform is the radiation characteristics of the
• Ultrasonic transducers In particular, the higher frequencies have a higher directivity within the transducer bandwidth, so that the spectrum tends to become lower frequency as the angle to the transducer axis of symmetry increases. As a result of the beam drift as a result of the flow to be measured, depending on the flow rate, different angular components of the emission and reception lobes of the ultrasonic transducers with correspondingly different transfer functions contribute more or less to the overall signal.
• the change in the signal shape can not be completely compensated by a focusing reflection surface, as will be explained with reference to a prior art ultrasonic flow sensor 110 shown in FIG.
• the ultrasonic flow sensor 110 can be used, for example, wholly or partially in a flow tube 12, which is only indicated by dashed lines in FIG. 2 and through which a fluid medium flows in a main flow direction 14.
• the ultrasonic flow sensor 110 includes a first ultrasonic transducer 16 and a second ultrasonic transducer 118 and a curved reflection surface 120.
• FIGS. 3A to 3D The behavior of the wavefronts of the ultrasonic signals and the sound focusing is shown in FIGS. 3A to 3D in a schematic diagram.
• FIG. 3A illustrates a situation in which the curvature of the reflection surface 120 has been selected such that, when the flow is at rest, the ultrasonic waves are transmitted from an ultrasonic transducer 16, 18 to the ultrasonic transducer be focused on others. If a flow is then added which has a certain velocity profile in the flow tube 12, then the focus moves not only in the flow direction but also with a component lying transversely thereto (see FIG. 3B). In contrast, in FIG.
• the curvature of the reflection surface 120 has been reduced to such an extent that the ultrasound signals are focused at least on the wall of the flow tube 1 12 at the same flow rate and flow profile as in FIG. 3B, although too far downstream of the second ultrasound transducer 1 18 If the flow now settles again, which is shown in FIG. 3C, the curvature of the reflection surface 120 is no longer sufficient for complete focusing.
• FIG. 4 shows an exemplary embodiment of an ultrasonic flow sensor 110 according to the invention.
• This ultrasonic flow sensor 1 10 is again wholly or partially in a flow tube 1 2, which is again indicated in Figure 4 only indicated by dashed lines, used.
• the ultrasonic flow sensor 1 10 can also be wholly or partially integrated into a tube wall of the flow tube 1 10 or include the pipe wall.
• the ultrasonic flow sensor 110 according to FIG. 1 comprises a waveguide 122, which is designed as a channel-like reflection and / or guide device.
• the waveguide 122 is configured to conduct the ultrasonic signals from one of the ultrasonic transducers 16, 118 to the other via a plurality of reflections.
• An opening cross-section of the waveguide 122 and a distance to the ultrasonic transducers 1 16, 1 18 can be designed such that that angular range of the ultrasonic transducer 1 16, 1 18 is detected, which contributes to the total signal due to the expected flow measuring range and within which the transfer function changes significantly , Depending on the flow rate or jet drift, different angular components with different numbers of reflections contribute to the overall signal. Accordingly, the ultrasonic flow sensor is arranged such that the ultrasonic waves between the ultrasonic transducers 1 16, 1 18 can be transmitted on at least two different ultrasonic paths 124, these ultrasonic paths differing in the number of their reflections. In the exemplary embodiment illustrated in FIG.
• two ultrasonic paths 124 are shown by way of example, one with 25 reflections and one with 17 reflections. In this case, none of the ultrasonic paths 124 should significantly dominate the other ultrasonic paths 124. Thus, there should be at least two different ultrasonic paths 124 whose sound energy components differ by a maximum of a factor of 10, preferably by a maximum of a factor of 5 or less.
• the energy portions of these various ultrasonic paths 124 may be detected experimentally, such as by masking other ultrasonic paths 124, such as by appropriate filters, masks, or similar elements, and then measuring the transmitted energy.
• an empirical or semiempirical determination of the energy components can also take place. This can be done, for example, such that from a known radiation characteristic of the ultrasonic transducers 16 and / or 18, the components attributable to the respective ultrasonic paths 124 are calculated or determined, for example, by simulation.
• the ultrasonic waves of the ultrasonic paths 124 depending on the sound path constructively or destructively interfere with each other, so that different modes can form, similar to a multimode optical fiber. Overall, this complex superposition of different portions of the emission and reception lobes to the effect that the converter influence is reduced and overall a more stable and clearer transit time measurement is possible.
• the walls 126 of the waveguide 122 thus act as reflection surfaces 120, on which reflection, preferably multiple reflection, can take place.
• the waveguide 122 is preferably configured symmetrically to the ultrasonic flow sensors 1 10. The waveguide 122 is traversed by the fluid medium.
• FIG. 5 shows a perspective illustration of a possible embodiment of the waveguide 122.
• the waveguide 122 knows thereby for an oblique coupling of the ultrasonic signals, obliquely to the main flow direction 1 14, openings 128. These openings 128 can be configured, for example, in the form of recesses from partial openings for coupling and uncoupling the ultrasonic signals.
• the waveguide 122 may have a channel-like, tubular structure.
• FIG. 6 shows an alternative embodiment of the ultrasonic flow sensor 10 according to FIG.
• two ultrasonic paths 124 are shown by way of example again. one with 5 reflections and one with 9 reflections.
• further ultrasonic paths 124 may exist, which are not shown in FIG.
• coupling elements 130 can be provided for improving the coupling or decoupling of the ultrasound signals.
• these coupling elements 130 may be curved coupling surfaces.
• These form supportive reflection geometries at the inlet and outlet of the waveguide 122 which, as shown in Figure 6, for example, can be configured curved.
• another embodiment is in principle possible, for example, a configuration with straight coupling surfaces as coupling elements 130.
• the curved design and coupling for example, a flush mounting of the ultrasonic transducer 1 16, 1 18 is possible or easier.
• FIG. 7 shows a configuration of a waveguide 122, which may be referred to as a
• the ultrasonic flow sensor 1 10 or the waveguide 122 is configured as a plug-in sensor 132, which can be introduced into the flow tube 1 12 and / or mounted in this.
• the waveguide 122, so the reflection or guide device, parts of the flow tube 1 12 be or be configured identically with this.
• the waveguide 122 may in particular be flowed through by the entire flow or by a certain proportion of the same.
• the waveguide 122 may be used to aerodynamically conduct, besides the ultrasound, also the flow of the fluid medium, and may for example be rectangular, triangular, polygonal, circular, oval shaped in a similar manner.
• FIG. 8 once again shows an exemplary embodiment of an ultrasonic flow sensor 110.
• the ultrasonic transducers 1 16, 1 18 are not arranged obliquely to an axis of the waveguide 122, but in axial symmetry to the waveguide 122 or its longitudinal extension axis.
• the waveguide 122 may, as in the other embodiments, be wholly or partially integrated in the flow tube, but may also be designed completely or partially different from the flow tube, as shown in Figure 8.
• different ultrasonic paths 124 are shown by way of example, namely an ultrasonic path with two reflections, an ultrasonic path with a reflection and an ultrasonic path, in which no reflection takes place.
• the waveguide 122 may be rounded in this and in other embodiments at its inlet and outlet openings and / or be conical and / or taper conically or rounded and then expand again. Such possible geometries are shown in FIGS. 9 and 10, which respectively show longitudinal sections parallel to a main flow direction 14.
• the waveguide 122 may be channel-like, U-shaped, tubular, trough-shaped or groove-like.
• Figure 1 1 shows an embodiment of a trough-shaped waveguide 122, which is introduced into a flow tube 1 12 and inlet and outlet ports 134 for the fluid medium and nozzle 136 has openings 128 for the coupling and decoupling of ultrasound signals.
• the waveguide 122 is designed as a channel, which has a total of a trough shape.
• FIG. 12A the waveguide 122 is shown in a perspective view, whereas FIG. 12B shows a cross-section in a plane perpendicular to the main flow direction 14, from which the shape of the bathtub clearly emerges.
• FIGS. 13A to 13D show various alternative cross sections of the waveguide
• FIG. 13A corresponds to the exemplary embodiment according to FIG. 12B and shows a trough shape.
• the exemplary embodiments in FIGS. 13B and 13C show U-shapes of different widths, and the exemplary embodiment in FIG. 13D shows a channel shape.
• FIGS. 14 and 15 show exemplary embodiments of an ultrasonic flow sensor 110, in which the waveguide 122 is at least partially identical to the flow tube 12.
• Such a configuration can in particular be such that the ultrasonic transducers 16, 18 are arranged such that their symmetry or main emission axes extend in the main flow direction 14.
• Walls 126 of the flow tube 12 may optionally be curved and, as shown optionally in FIGS. 14 and 15, form curved reflecting surfaces 120.
• the flow of the fluid medium, as shown in Figure 14, on one side of the flow tube 1 12 are coupled into this or, as shown in Figure 15, on opposite sides of the flow tube 1 12, wherein a portion of
• the waveguide 122 can also be arranged as a separate tube within the outer flow tube 112 or only partially into the tube Flow tube 1 12 are integrated.
• the waveguide 122 which acts as a reflection or guide device, can also be arranged completely or partially in a bypass 140 of the flow tube 1 12.
• this arrangement corresponds to the arrangement of Figure 14, but the waveguide 122 is not identical to the flow tube 1 12, but with a bypass 140. This bypass is via inlet and outlet ports 134, which also completely or partially into the flow tube 1 12th protrude and form a flow line, connected to the flow tube 1 12.
• the waveguide 122 acting as a reflection or guide device can also consist of parts of a reflection surface 120 combined with parts of the flow tube 1 12, so that, for example, reflections are used according to the invention both on the reflection surface 120 and on the tube wall of the flow tube 1 12 can.

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• 2009
  • 2009-10-13 DE DE102009045620A patent/DE102009045620A1/de not_active Withdrawn
• 2010
  • 2010-08-18 EP EP10751861A patent/EP2488835A1/de not_active Withdrawn
  • 2010-08-18 JP JP2012533538A patent/JP5479605B2/ja not_active Expired - Fee Related
  • 2010-08-18 US US13/501,393 patent/US8794080B2/en not_active Expired - Fee Related
  • 2010-08-18 WO PCT/EP2010/062046 patent/WO2011045107A1/de active Application Filing

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