Ultrasonic flowmeter

Abstract

An ultrasonic flowmeter includes a cylindrical flow path having a rectangular cross section through which a fluid to be measured flows, a pair of ultrasonic transducers respectively positioned upstream and downstream of the cylindrical flow path, a measuring unit, a calculating unit, and a partition. The measuring unit measures a propagation time of an ultrasonic wave propagating from one ultrasonic transducer to the other. The calculating unit calculates a flow rate and a flow volume of the fluid to be measured based on the propagation time measured by the measuring unit. The partition is arranged in the cylindrical flow path in parallel with a flow direction of the fluid to be measured and separates the cylindrical flow path into a plurality of divided flow paths. In addition, the partition is provided with a notch portion or an opening portion allowing communication between the divided flow paths in a shortcut path that forms a shortcut route in a normal propagation path along which the ultrasonic wave propagates from one ultrasonic transducer to the other.

Description

Technical Field

[0001] This disclosure relates to an ultrasonic flow meter for measuring flow rate, wherein the flow path is divided into multiple layers. Background Technology

[0002] like Figure 6A and Figure 6B As shown, a conventional ultrasonic flow meter measures the flow rate of a fluid flowing in a flow path 105, which is divided into multiple layers by a baffle 109. This configuration allows ultrasonic waves emitted from an ultrasonic transceiver 116 to be reflected at the base plate 107 of the flow path 105 and received by an ultrasonic transceiver 117 (see, for example, Patent Document 1).

[0003] The ultrasonic flow meter described in Patent Document 1 has a shortcut path R, which is different from the normal propagation paths 124 and 125. The ultrasonic waves propagate along this shortcut path to another ultrasonic transceiver without being reflected at the base plate 107.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-103149 Summary of the Invention

[0007] In the aforementioned conventional configuration with a V-shape, ultrasonic waves can travel along normal propagation paths 124 and 125, in which they are emitted from ultrasonic transceiver 116, reflected at the base plate 107 of flow path 105, and received by ultrasonic transceiver 117. In the aforementioned conventional configuration, ultrasonic waves can also travel along a shortcut path R, in which they reach ultrasonic transceiver 117 without reflection. Therefore, in this conventional configuration, the diffracted wave signal traveling through the shortcut path R may interfere with and affect the normally received signal traveling through normal propagation paths 124 and 125.

[0008] If the fluid being measured is hydrogen, the speed of sound in hydrogen tends to be higher and the ultrasound waves tend to have longer wavelengths compared to air, city gas, or LP gases, making it more prone to diffraction. Therefore, interference from diffracted wave signals can affect the normal received signal, thereby reducing the accuracy of flow measurement.

[0009] exist Figure 6A In the diagram, for illustration purposes, the shortcut path R is represented by a dashed line. The actual shortcut path corresponds to the entire area of ​​the triangle enclosed by the normal propagation paths 124, 125 and the inner wall surface 105a of the flow path 105.

[0010] This disclosure provides an ultrasonic flow meter that, in the presence of a shortcut path relative to the normal propagation path, can minimize the adverse effects of diffracted wave signals traveling along the shortcut path on normal received signals traveling along the normal path.

[0011] The ultrasonic flow meter according to this disclosure includes a cylindrical flow path with a rectangular cross-section through which a fluid to be measured flows; a pair of ultrasonic transceivers located in the upstream and downstream portions of the cylindrical flow path, respectively; a measuring unit; a calculating unit; and a baffle. The measuring unit measures the propagation time of ultrasonic waves from one ultrasonic transceiver to the other. The calculating unit calculates the flow velocity or flow rate of the fluid to be measured based on the propagation time measured by the measuring unit. The baffle is arranged in the cylindrical flow path parallel to the flow direction of the fluid to be measured. The baffle divides the cylindrical flow path into multiple separate flow paths. The cylindrical flow path includes a normal propagation path and a fast propagation path, the fast propagation path forming a fast route with respect to the normal propagation path, through which ultrasonic waves propagate from one ultrasonic transceiver to the other. The baffle has notches or openings in the region corresponding to the fast propagation path, and the separate flow paths communicate with each other via the notches or openings.

[0012] In the ultrasonic flow meter disclosed herein, a baffle plate has a notch or opening connecting the separated flow paths in the region corresponding to the shortcut path of the normal propagation path of the ultrasonic wave. This minimizes the adverse effects of interference caused by diffracted wave signals forming the shortcut path of the normal propagation path, which interferes with the normal received signal traveling along the normal propagation path. Therefore, even in hydrogen environments where the speed of sound tends to be higher and the ultrasonic waves tend to have longer wavelengths, a high-precision ultrasonic flow meter can be achieved. Attached Figure Description

[0013] Figure 1 This is a perspective cross-sectional view showing the flow path portion of an ultrasonic flow meter according to a first embodiment of the present disclosure.

[0014] Figure 2 This is a side view showing the flow path of an ultrasonic flow meter according to a first embodiment of the present disclosure.

[0015] Figure 3 This is a cross-sectional view showing the construction of an ultrasonic flow meter according to a first embodiment of the present disclosure.

[0016] Figure 4A This is a detailed view showing the opening according to the first embodiment of the present disclosure.

[0017] Figure 4BThis is a detailed view showing the opening according to the first embodiment of the present disclosure.

[0018] Figure 5A This is a detailed view showing another construction of the opening according to the second embodiment of the present disclosure.

[0019] Figure 5B This is a detailed view showing another construction of the opening according to the second embodiment of the present disclosure.

[0020] Figure 5C This is a detailed view showing another construction of the opening according to the second embodiment of the present disclosure.

[0021] Figure 6A This is a cross-sectional view showing the construction of a conventional ultrasonic flow meter.

[0022] Figure 6B This is a side view showing the construction of a conventional ultrasonic flow meter. Detailed Implementation

[0023] According to a first aspect, an ultrasonic flow meter includes a cylindrical flow path with a rectangular cross-section through which a fluid to be measured flows; a pair of ultrasonic transceivers located in the upstream and downstream portions of the cylindrical flow path, respectively; a measuring unit; a calculating unit; and a baffle. The measuring unit measures the propagation time of an ultrasonic wave from one of the ultrasonic transceivers to the other. The calculating unit calculates the flow velocity or flow rate of the fluid to be measured based on the propagation time measured by the measuring unit. The baffle is arranged in the cylindrical flow path parallel to the flow direction of the fluid to be measured. The baffle divides the cylindrical flow path into multiple separate flow paths. The cylindrical flow path includes a normal propagation path and a fast propagation path, the fast propagation path forming a fast route about the normal propagation path, through which ultrasonic waves propagate from one of the ultrasonic transceivers to the other. The baffle has notches or openings in the region corresponding to the fast propagation path, and the separate flow paths communicate with each other via the notches or openings. This minimizes the adverse effects of diffracted wave signals traveling through the fast path on the normal received signal traveling along the normal propagation path. Therefore, even in hydrogen environments where the speed of sound tends to be higher and the ultrasound tends to have longer wavelengths, high-precision ultrasonic flow meters can be achieved.

[0024] In the ultrasonic flow meter that can be implemented in conjunction with the first aspect, the opening is formed such that the baffle has an opening area ratio of 20% or greater in the region corresponding to the fast propagation path. This allows for a reduction in the ratio of diffracted and reflected signals in the diffracted wave signal that are reflected by the baffle and reach the receiving side of the ultrasonic transducer receiver, thereby minimizing the amplitude of the diffracted wave signal that may interfere with and affect the normal received waveform. Therefore, it is possible to achieve a high-accuracy ultrasonic flow meter even in hydrogen environments where the speed of sound tends to be higher and the ultrasonic waves tend to have longer wavelengths.

[0025] In the ultrasonic flow meter according to the third aspect, which can be implemented in conjunction with the first or second aspect, the opening includes multiple openings. This makes it possible to suppress the attenuation of the received signal due to reflection or diffusion of ultrasonic wave propagation. Furthermore, the distribution of the openings allows disturbances in the flow of the measured fluid to be dispersed, thereby stabilizing the flow in the separated flow path. This enables high-precision flow measurement.

[0026] In an ultrasonic flow meter that can be implemented in combination with the first or second aspect, the opening is constructed as a porous body or mesh with numerous micropores. This allows for the setting of a minute shape of the opening, thereby suppressing the attenuation of ultrasonic waves and stabilizing the flow of the measured fluid.

[0027] In the ultrasonic flow meter of the fifth aspect, which can be implemented in combination with any of the first to fourth aspects, the baffles include a plurality of baffles. At least one of the plurality of baffles includes an opening having a shape different from the opening of another baffle, or the ultrasonic flow meter also includes a baffle without an opening. This makes it possible to minimize the effects of disturbances in the flow of the measured fluid caused by the opening, thereby suppressing the attenuation of ultrasonic waves and stabilizing the flow of the measured fluid.

[0028] The embodiments will be described in detail with reference to the accompanying drawings. However, unnecessary descriptions may be omitted. For example, detailed descriptions of well-known matters or repeated descriptions of substantially the same structures may be omitted.

[0029] Please note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure, and are not intended to limit the subject matter of the appended claims.

[0030] (First Implementation)

[0031] Reference Figures 1 to 4B The first embodiment is described.

[0032] Figure 1 This is a cross-sectional perspective view showing a schematic construction of an ultrasonic flow meter according to a first embodiment of the present disclosure. Figure 2 It is along the flow path section Figure 1The cross-sectional view taken from the BB line. Figure 3 This is a view showing the construction of the ultrasonic flow meter 30, and it is along... Figure 1 The cross-sectional view taken from line AA. Note that the measurement circuit (measurement unit) 28 and the calculation circuit (calculation unit) 29 are mounted on the circuit board (not shown), but for ease of illustration, as shown... Figure 3 They were taken out as shown.

[0033] like Figure 1 , Figure 2 and Figure 3 As shown, the ultrasonic flow meter includes a measuring flow path 17, ultrasonic transmitter and receiver 12, 13, measuring unit 28, calculation unit 29, and partitions 3A to 3H.

[0034] The flow path 1 includes a cylindrical flow path 2 with a rectangular cross-section through which the fluid to be measured flows. The cylindrical flow path 2 is defined by a first surface 11, a second surface 16, a first side surface 25, and a second side surface 26, all of which surround the cylindrical flow path 2. The interior of the cylindrical flow path 2 is divided into partitioned flow paths 6A to 6I, each with a rectangular cross-section, by baffles 3A to 3H arranged parallel to the flow direction of the fluid to be measured, thereby forming a multi-layered flow path 10. In other words, the baffles 3A to 3H are configured in the cylindrical flow path 2 to be parallel to the flow direction of the fluid to be measured, thereby dividing the cylindrical flow path 2 into multiple partitioned flow paths 6A to 6I.

[0035] Figure 1 Is Figure 2 The cross-section is taken at the location of the partition flow path 6E. Note that in the partition flow path 6E, [the following is not shown]. Figure 1 The surface in front of the picture ( Figure 2 The first side surface 25 faces the partitions 3A to 3D and forms a cylindrical flow path 2.

[0036] The first surface 11 (i.e., the upper surface) is one of the two surfaces facing each other and confronting the separating flow paths 6A to 6I of the cylindrical flow path 2. Ultrasonic transceiver 12 and ultrasonic transceiver 13 are respectively arranged in the upstream and downstream portions of the first surface 11. In other words, a pair of ultrasonic transceivers 12 and 13 are located in the upstream and downstream portions of the cylindrical flow path 2, respectively. The first surface 11 includes a first ultrasonic transmission window 14 and a second ultrasonic transmission window 15. The second surface 16 (i.e., the lower surface) is one of the two surfaces facing each other and confronting the separating flow paths 6A to 6I. The second surface 16 serves as a reflecting surface for ultrasonic waves.

[0037] A pair of ultrasonic transceivers 12 and 13 and a multilayer flow path 10 define a measurement flow path 17 through which ultrasonic waves propagate. Ultrasonic waves emitted from ultrasonic transceiver 12 travel along propagation path P1, are reflected by the second surface 16, travel along propagation path P2, and are received by ultrasonic transceiver 13. Ultrasonic waves emitted from ultrasonic transceiver 13 travel along propagation path P2, are reflected by the second surface 16, travel along propagation path P1, and are received by ultrasonic transceiver 12.

[0038] like Figure 3 As shown, each of the partitions 3A to 3H forms a propagation path P1, P2 for the ultrasonic wave (see reference). Figure 3 An opening 18 is formed in the region of the shortcut path (the triangular region surrounded by the propagation paths P1, P2 and the first surface 11). Adjacent partitioned flow paths are connected to each other via the opening 18. Hereinafter, propagation paths P1, P2 may be referred to as "normal propagation paths," and the region forming the shortcut path may be referred to as "shortcut path R." In other words, each of the partitions 3A to 3H has an opening 18 that allows partitioned flow paths 6A to 6I to be connected to each other in the region corresponding to the shortcut path R that forms the shortcut path with respect to the normal propagation paths P1, P2 (the ultrasonic waves propagate from the ultrasonic transceiver 12 through the normal propagation paths P1, P2 to the ultrasonic transceiver 13).

[0039] The outermost separator flow paths 6A and 6I are referred to as "outer flow paths". The inner separator flow paths 6B to 6H are referred to as "inner flow paths".

[0040] As described above, the arrows indicated by the normal propagation paths P1 and P2 correspond to the propagation paths along which the ultrasonic waves propagate to traverse the measurement flow path 17. Note that the direction of the arrows indicates the travel of the ultrasonic waves from the upstream ultrasonic transceiver 12 to the downstream ultrasonic transceiver 13. When the ultrasonic waves travel from the downstream ultrasonic transceiver 13 to the upstream ultrasonic transceiver 12, the direction of the arrows will be reversed.

[0041] The signal emitted from the first ultrasonic transceiver 12 or the second ultrasonic transceiver 13 is processed by the measurement circuit 28 (measurement unit) for propagation time measurement, and the flow velocity or flow rate of the fluid being measured is calculated by the calculation circuit 29 (calculation unit) using known methods.

[0042] Figure 4A and Figure 4BDetails of the openings 18 formed in the partitions 3A to 3H are shown. The openings 18 are formed in the partitions 3A to 3H in portions corresponding to the shortcut paths R of the normal propagation paths P1 and P2 of the ultrasound. The portions corresponding to the shortcut paths R are the areas surrounded by the normal propagation paths P1 and P2 and the first surface 11.

[0043] Figure 4A This is a detailed view showing the second partition 3E. Figure 4A An example of the shape of the opening 18 is shown. The opening 18 is made of a porous body 22 having a plurality of micropores 24. Note that the spacing between the pore size and the micropores 24 is adjusted so that the necessary rectification effect can be maintained. The porous body 22 may comprise a perforated plate or an etched plate, in which a plurality of pores are mechanically formed, and in which micropores are chemically formed, which can provide greater manufacturability.

[0044] Figure 4B Another example of the shape of the opening 18 is shown. The opening 18 is made of a mesh body 23 made of metal mesh. The ratio of the mesh count to the opening area of ​​the mesh body 23 should be set within a range that can maintain the necessary rectification effect.

[0045] The operation of the ultrasonic flow meter 30 according to this disclosure will now be described.

[0046] like Figure 3 As shown, the fluid being measured flows into the cylindrical flow path 2 through inlet 21 and is separated into the partition flow paths 6A to 6I by partitions 3A to 3H.

[0047] The propagation time of the ultrasound is measured in such a way that the ultrasound is repeatedly transmitted and received between the ultrasound transmitter and receiver 12 and the ultrasound transmitter and receiver 13, such that the ultrasound is reflected at the second surface 16 to cross the measured fluid flowing through the measuring flow path 17 in the separated flow paths 6A to 6I.

[0048] The ultrasonic wave emitted from ultrasonic transceiver 12 (or ultrasonic transceiver 13) travels through ultrasonic transmission window 14 (or ultrasonic transmission window 15), enters the partitioned flow paths 6A to 6I, and is subsequently reflected by the second surface 16. The ultrasonic signal reflected by the second surface 16 then travels through ultrasonic transmission window 15 (or ultrasonic transmission window 14) and is received by ultrasonic transceiver 13 (or ultrasonic transceiver 12). During propagation, the ultrasonic signal is repeatedly reflected multiple times at partitions 3A to 3H, the first side surface 25, and the second side surface 26.

[0049] Because the partitions 3A to 3H are provided with openings 18, the diffracted wave signal traveling on the shortcut path R, which forms the shortcut path of the normal propagation paths P1 and P2, has a lower reflection ratio at the partitions 3A to 3H, the first side surface 25, and the second side surface 26, which serve as reflecting surfaces, compared to the normal received signal traveling through the normal propagation paths P1 and P2. This allows for a reduction in the amplitude of the diffracted wave signal caused by multiple reflections at the reflecting surfaces. It also minimizes the adverse effects of the diffracted wave signal traveling along the shortcut path R on the normal received signal traveling along the normal propagation paths P1 and P2, thereby improving measurement accuracy.

[0050] If the entire surface area of ​​the walls of partitions 3A to 3H is open in the region of the ultrasonic wave propagation path, the rectification effect on the measured fluid will be reduced even if multiple reflections of the ultrasonic wave never occur. This reduction in effect may lead to differences or fluctuations in the velocity distribution between the separated flow paths 6A to 6I, thereby reducing the measurement accuracy or the measurable area.

[0051] In this embodiment, the opening 18 is disposed within the area surrounded by the normal propagation paths P1 and P2 and the first surface 11 of the partitions 3A to 3H to maintain a rectifying effect on the fluid being measured. This allows for the reduction of diffraction wave signals and the maintenance of a rectifying effect on the fluid being measured. More specifically, this allows for the reduction of diffraction wave signals in ultrasonic wave propagation and the dispersion of disturbances in the flow of the fluid being measured through the opening in the opening 18, thereby stabilizing the flow in the separated flow paths 6A to 6I. This enables flow measurement with high accuracy.

[0052] The opening area ratio of the opening 18 in the region of the shortcut path R can be between 20% and 85% (inclusive). If the above condition is met, the adverse effects of the diffracted wave signal traveling through the shortcut path R on the normal received signals traveling through the normal propagation paths P1 and P2 can be reduced.

[0053] (Second Implementation)

[0054] Next, we will refer to Figure 5A , Figure 5B and Figure 5C The second embodiment according to this disclosure will be described below.

[0055] Figure 5A Another configuration of the opening 18 according to the second embodiment of the present disclosure is shown, in which any component of this embodiment having the same function as the corresponding component of the first embodiment described above will be indicated by the same reference numerals as the corresponding component.

[0056] In the second embodiment, a plurality of openings 31 are provided as openings 18 near only the first surface 11 in the portion corresponding to the shortcut path R, which is the shortest shortcut route between the ultrasonic transceiver 12 and the ultrasonic transceiver 13.

[0057] The ultrasonic signal emitted from the ultrasonic transceiver 12 (or ultrasonic transceiver 13) travels through the ultrasonic transmission window 14 (or ultrasonic transmission window 15), enters the partitioned flow paths 6A to 6I, and is then reflected by the second surface 16. Subsequently, the ultrasonic signal reflected by the second surface 16 travels through the ultrasonic transmission window 15 (or ultrasonic transmission window 14) and is received by the ultrasonic transceiver 13 (or ultrasonic transceiver 12). During propagation, the ultrasonic signal is repeatedly reflected multiple times at the partitions 3A to 3H, the first side surface 25, and the second side surface 26.

[0058] Incidentally, the diffracted wave signal received by the ultrasonic transceiver 13 (or ultrasonic transceiver 12) includes the following: a portion of the ultrasonic waves emitted from the ultrasonic transceiver 12 (or ultrasonic transceiver 13) and subsequently traveling through the ultrasonic transmission window 14 (or ultrasonic transmission window 15) are diffracted at the end 19 of the ultrasonic transmission window 14 (or the end 20 of the ultrasonic transmission window 15). Subsequently, the diffracted portion of the ultrasonic waves travels along the shortest path, diffracts again at the end 20 of the ultrasonic transmission window 15 (or the end 19 of the ultrasonic transmission window 14), and is received by the ultrasonic transceiver 13 (or ultrasonic transceiver 12). During propagation, the diffracted wave signal is repeatedly reflected multiple times at the partitions 3A to 3H, the first side surface 25, and the second side surface 26.

[0059] In this embodiment, the opening 18 in the shortcut path R reduces the area of ​​the reflective surface used for collision, thereby reducing the diffraction wave signal caused by multiple reflections. In this embodiment, the opening 18 is only provided in the portion near the region between the end 19 of the ultrasonic wave passage window 14 and the end 20 of the ultrasonic wave passage window 15 in the partitions 3A to 3H, i.e., the shortest path portion of the shortcut path R, thereby reducing the diffraction wave signal. Furthermore, since the opening area ratio of the partitions 3A to 3H to the entire wall surface is small, the deterioration of the rectification effect on the measured fluid can be suppressed, thereby achieving flow measurement with good accuracy.

[0060] Figure 5B An example of another construction of partitions 3A to 3H is shown, in which example Figure 5A The opening 18 shown increases toward the first surface 11 to form a notch 32 as a single recess facing the first surface 11. This shape simplifies the shape of the partition 3E and improves the machinability of the partition 3E, while also providing the effect of reducing diffraction wave signals.

[0061] like Figure 5C As shown, the partition 3E can be formed with multiple notches 33. In this case, with Figure 5B Similarly, it can reduce diffraction wave signals.

[0062] As shown in the first and second embodiments, the partitions 3A to 3H have openings 18 formed in the regions corresponding to the shortcut path R, which forms a shortcut route for the normal propagation paths P1 and P2 of the ultrasonic waves. The openings 18 have the above-described structure. Furthermore, a first ultrasonic transceiver 12 and a second ultrasonic transceiver 13 are provided on the first surface 11, i.e., one of the two opposing surfaces of the measuring flow path 17. Ultrasonic waves are emitted from one of the first ultrasonic transceiver 12 and the second ultrasonic transceiver 13, reflected once or multiple times at the second surface 16 facing the first surface 11, and received by the other ultrasonic transceiver. This structure minimizes the adverse effects of the diffracted wave signal forming the shortcut route for the normal propagation path on the normally received signal traveling along the normal propagation path, thereby achieving a high-accuracy ultrasonic flow meter even in hydrogen environments where the speed of sound of ultrasonic waves tends to be higher and the ultrasonic waves tend to have longer wavelengths.

[0063] As described above, according to embodiments of the present disclosure, a pair of ultrasonic transceivers 12, 13 are configured such that the ultrasonic wave propagation path is V-shaped, i.e., the ultrasonic wave is reflected once at the second surface 16. However, the present disclosure is not limited to the above-described configuration. Other configurations are also possible, as long as the configuration includes a shortcut path R with respect to the normal propagation path and normal propagation paths P1, P2 where the ultrasonic wave is reflected at least once at the second surface, such as a W-shaped ultrasonic wave propagation path (not shown) where the ultrasonic wave is reflected twice at the second surface 16 and once at the first surface 11.

[0064] In this implementation, all layers of the multilayer flow path 10 are used for the measurement flow path 17. However, for measurement flow paths with large dimensions, only one layer of the multilayer flow path 10 may be used, or the propagation surface of the ultrasonic waves may overlap with multiple layers. In these cases, the same effect can be obtained.

[0065] exist Figure 1 In this embodiment, all partitions 3A to 3H are provided with openings. However, if the diffracted wave signal forming a shortcut along the normal propagation paths P1 and P2 has little impact on the accuracy of flow measurement, thus ensuring the accuracy of flow measurement, then openings can be provided in the minimum number of partitions 3A to 3H. If the above conditions are met, the shape of the opening formed in the opening 18 is not limited to the shape described in the embodiment.

[0066] Industrial availability

[0067] The ultrasonic flow meter according to this disclosure can be applied to gas metering or measuring devices for hydrogen.

[0068] Explanation of reference numerals in the attached figures

[0069] 3A to 3H partition

[0070] 6A to 6I separated flow path

[0071] 10+ layers of flow paths

[0072] 11 First Surface

[0073] 12, 13, 116, 117 Ultrasonic Transmitter and Receiver

[0074] 16 Second Surface

[0075] 17 Measurement Flow Path

[0076] 18. Opening

[0077] 22 porous body

[0078] 23 net bodies

[0079] 24 micropores

[0080] 28 Measurement loops (measurement units)

[0081] 29. Computational Loop (Computational Unit)

[0082] 30 Ultrasonic Flow Meter

[0083] 31 Opening

[0084] 32, 33 Notch

Claims

1. An ultrasonic flow meter, comprising: A cylindrical flow path with a rectangular cross-section through which the fluid to be measured flows; A pair of ultrasonic transceivers and receivers are located in the upstream and downstream sections of the cylindrical flow path, respectively. A measurement unit configured to measure the propagation time of an ultrasonic wave from one of the ultrasonic transceivers to the other. A calculation unit is configured to calculate the velocity or flow rate of the fluid being measured based on the propagation time measured by the measurement unit. as well as A baffle, arranged parallel to the flow direction of the fluid being measured, divides the cylindrical flow path into multiple separate flow paths. The pair of ultrasonic transceivers are located in the first surface of the cylindrical flow path. The ultrasonic wave emitted from the first of the ultrasonic transceivers travels along a first propagation path, is reflected by a second surface facing the first surface, travels along a second propagation path, and is received by the second of the ultrasonic transceivers. The ultrasonic wave emitted from the second of the ultrasonic transceivers travels along the second propagation path, is reflected by the second surface, travels along the first propagation path, and is received by the first of the ultrasonic transceivers. The cylindrical flow path includes Normal propagation path, which includes the first propagation path and the second propagation path; and A fast propagation path, forming a shortcut about the normal propagation path, through which ultrasound waves propagate from one of the ultrasound transmitters / receivers to the other via the normal propagation path, the fast propagation path being surrounded by the first propagation path, the second propagation path, and the first surface, and The partition A notch or opening is formed in a first region corresponding to the rapid propagation path, and the separated flow paths are interconnected via the notch or opening. No gaps or openings are formed in the second region, which is different from the first region, to allow the separated flow paths to communicate with each other.

2. The ultrasonic flow meter according to claim 1, characterized in that, The opening is formed such that the partition has an opening area ratio of 20% or greater in the region corresponding to the rapid propagation path.

3. The ultrasonic flow meter according to claim 1 or 2, characterized in that, The opening includes multiple openings.

4. The ultrasonic flow meter according to claim 1 or 2, characterized in that, The opening is constructed as a porous body or mesh with many micropores.

5. The ultrasonic flow meter according to claim 1 or 2, characterized in that, The partition includes multiple partitions, and At least one of the plurality of baffles includes an opening having a shape different from the opening of another baffle, or the ultrasonic flow meter further includes a baffle that does not have the opening.

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