Ultrasonic anemometer

Abstract

To provide an ultrasonic anemometer with which the device size and cost are reduced, and with which ultrasonic waves are received after being rotated multiple times.SOLUTION: An ultrasonic anemometer 100 comprises: a top plate 11 having a first flat surface 12 extending along a first direction and a second direction crossing the first direction; a first ultrasonic wave oscillator 31 and a second ultrasonic oscillator 32 mounted to the top plate 11 and arranged on both sides of the first flat surface 12 in the first direction; and a reflector plate including a second flat surface 22 parallel to the first flat surface 12 located facing the first flat surface 12 in a third direction crossing the first and the second directions and whose distance from the first flat surface 12 is a first distance, and including a third surface 23 the distance of which from the first ultrasonic oscillator 31 in the third direction is a second distance that is longer than the first distance.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to ultrasonic anemometers. [Background technology]

[0002] For example, a wind direction and speed measuring device is known that measures the wind direction and speed of a fluid to be measured based on the propagation time of ultrasonic waves transmitted and received between a pair of ultrasonic transmitters and receivers (see, for example, Patent Document 1). This wind direction and speed measuring device includes a housing in which a flow path through which the fluid to be measured flows is formed, and a pair of ultrasonic transmitters and receivers that are installed at a predetermined inclination relative to the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-77643 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional technology faces challenges in improving wind direction accuracy. Ultrasonic anemometers, which rely on receiving ultrasonic waves after multiple reflections, are technically difficult to develop. There is a demand for miniaturization and cost reduction in such ultrasonic anemometers.

[0005] An object of the present disclosure is to provide an ultrasonic anemometer that is small in size and low in cost, and receives ultrasonic waves after they are reflected multiple times. [Means for solving the problem]

[0006] The ultrasonic anemometer according to the present disclosure comprises a top plate having a first plane along a first direction and a second direction intersecting the first direction; a first ultrasonic oscillator and a second ultrasonic oscillator mounted on the top plate and arranged at a predetermined distance from the first plane in the first direction; and a reflector arranged opposite the first plane in a third direction intersecting the first and second directions, the reflector having a second plane parallel to the first plane and a third surface at a first distance from the first plane and a second distance longer than the first distance from the first ultrasonic oscillator and the second ultrasonic oscillator in the third direction. [Effects of the Invention]

[0007] The present disclosure can provide an ultrasonic anemometer that is small in size and low in cost, and receives ultrasonic waves after they are reflected multiple times. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view illustrating an ultrasonic anemometer according to a first embodiment. [Figure 2] 1 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to a first embodiment. [Figure 3] FIG. 2 is a plan view showing an example of the arrangement of a reflector and an ultrasonic oscillator. [Figure 4] FIG. 10 is a schematic diagram showing an example of distances between a plurality of ultrasonic oscillators. [Figure 5] FIG. 10 is a plan view showing an example of the arrangement of a reflector and an ultrasonic oscillator of an ultrasonic anemometer according to a second embodiment. [Figure 6] FIG. 10 is a plan view showing an example of the arrangement of a reflector and an ultrasonic oscillator of an ultrasonic anemometer according to a third embodiment. [Figure 7] FIG. 10 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to a comparative example. [Figure 8] FIG. 10 is a plan view showing an example of the arrangement of a reflector and an ultrasonic oscillator of an ultrasonic anemometer according to a fourth embodiment. [Figure 9] FIG. 10 is a plan view showing an example of the arrangement of a reflector and an ultrasonic oscillator of an ultrasonic anemometer according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an ultrasonic anemometer according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description. In addition, the terms "upper" and "lower" may be used in this specification. These refer to the "upper" and "lower" in the state shown in FIG. 2, where the side where the top plate 11 is located is referred to as "upper" and the side where the reflector plate 21 is located is referred to as "lower" in the Z-axis direction. The actual arrangement of the ultrasonic anemometer 100 is not limited to this. In addition, although the term "ultrasonic oscillator" is used in this specification, it has not only the function of emitting ultrasonic waves but also the function of an ultrasonic receiver.

[0010] [Ultrasonic anemometer 100 according to the first embodiment] FIG. 1 is a schematic perspective view illustrating an ultrasonic anemometer 100 according to the first embodiment. FIG. 2 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100 according to the first embodiment. FIG. 3 is a plan view illustrating an example of the arrangement of a reflector 21 and ultrasonic oscillators 31 to 34. FIG. 4 is a schematic view illustrating an example of distances Vx, Vy, Va, Vc, and Vd between the ultrasonic oscillators 31 to 34. Note that in each drawing, the X-axis direction, the Y-axis direction, and the Z-axis direction, which are orthogonal to each other, may be illustrated. The X-axis direction, the Y-axis direction, and the Z-axis direction do not have to be orthogonal to each other. The X-axis direction, the Y-axis direction, and the Z-axis direction may be any direction. The X-axis direction is an example of a first direction. The Y-axis direction is an example of a second direction intersecting with the first direction. The Z-axis direction is an example of a third direction intersecting with the first direction and the second direction.

[0011] 1 and 2 is a wind direction and speed measurement device that measures the wind direction and speed of a fluid to be measured based on the propagation time of ultrasonic waves transmitted and received between an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic anemometer 100 can determine wind speed from fluctuations in the speed of sound in the air (approximately 340 m / s). The distance between the ultrasonic transmitter and the ultrasonic receiver is known, and the wind direction and speed of the fluid can be measured based on the difference in the propagation time of the ultrasonic waves.

[0012] As shown in Fig. 1, the ultrasonic anemometer 100 includes a first housing 10, a second housing 20, and multiple support columns 13. The first housing 10 and the second housing 20 are spaced apart in the Z-axis direction. The multiple support columns 13 extend in the Z-axis direction and support the first housing 10 relative to the second housing 20. The lower ends of the support columns 13 are fixed to the second housing 20, and the upper ends of the support columns 13 are fixed to the first housing 10. The first housing 10 mounts multiple ultrasonic oscillators 30 and a circuit board. Note that a cover that covers the top of the first housing 10 is not shown in Fig. 1.

[0013] As shown in FIG. 2, the ultrasonic anemometer 100 includes a first housing 10 that also functions as a top plate 11, a plurality of ultrasonic oscillators 30, and a second housing 20 that also functions as a reflector 21.

[0014] [Tabletop 11] Specifically, the top plate 11 is provided on the first housing 10. The top plate 11 is arranged on the bottom of the first housing 10. The top plate 11 is, for example, disk-shaped. The top plate 11 is provided with a holder that holds a plurality of ultrasonic oscillators 30. The top plate 11 also has a surface that reflects ultrasonic waves transmitted from the ultrasonic oscillators 30.

[0015] [1st plane 12] The top plate 11 has a first plane 12. The first plane 12 is a surface along the X-axis direction and the Y-axis direction. The first plane 12 is the bottom surface of the top plate 11.

[0016] [Multiple ultrasonic oscillators 30] The multiple ultrasonic oscillators 30 include ultrasonic oscillators 31 to 34. The ultrasonic oscillator 31 is an example of a first ultrasonic oscillator, the ultrasonic oscillator 32 is an example of a second ultrasonic oscillator, the ultrasonic oscillator 33 is an example of a third ultrasonic oscillator, and the ultrasonic oscillator 34 is an example of a fourth ultrasonic oscillator. The multiple ultrasonic oscillators 30 are mounted on the top board 11. The ultrasonic oscillator 30 is an ultrasonic transmitting unit that transmits ultrasonic waves and an ultrasonic receiving unit that receives ultrasonic waves. The arrangement of the multiple ultrasonic oscillators 30 will be described later.

[0017] [Reflector 21] Specifically, the reflecting plate 21 is provided on the upper part of the second housing 20. The reflecting plate 21 is disposed so as to face the top plate 11 in the Z-axis direction. A space is formed between the top plate 11 and the reflecting plate 21, through which the fluid to be measured can pass. The fluid to be measured may be, for example, air. The reflecting plate 21 has a surface that reflects the ultrasonic waves transmitted from the ultrasonic oscillator 30.

[0018] [2nd plane 22] The reflector 21 has a second plane 22 and a third plane 23. The second plane 22 may be the upper surface of the reflector 21. The second plane 22 faces the first plane 12 in the Z-axis direction and is a plane parallel to the second plane 22. "Parallel" includes "substantially parallel." The second plane 22 is a plane along the X-axis direction and the Y-axis direction. As shown in FIG. 3, the second plane 22 is disposed in the center of the reflector 21 when viewed in the Z-axis direction. The reflector 21 has, for example, a circular shape. Furthermore, when viewed in the Z-axis direction, the second plane 22 includes an area overlapping with the first plane 12.

[0019] [Side 3 23] The third surface 23 is formed around the second plane 22 when viewed in the Z-axis direction. The third surface 23 is formed so as to surround the second plane 22. The third surface 23 may be, for example, a conical slope. As shown in FIG. 2 , in a cross section along the XZ plane, the third surface 23 includes an inclined surface that is inclined with respect to the second plane 22. The upper end of the third surface 23 is located closer to the second plane 22 than the lower end of the third surface 23 in the X-axis direction. The lower end of the third surface 23 is located further outward than the upper end of the third surface 23 in the Z-axis direction. Here, the upper end is the end closest to the top plate 11 when viewed in the Z-axis direction, and the lower end is the end farthest from the top plate 11. The third surface 23 is inclined outward so as to face the opposite side from the second plane 22. The outer end of the third surface 23 is located lower than the inner end. "Outwardly facing" may also mean that the outer end is located lower than the inner end. The downward direction is the direction away from the top board 11 in the Z-axis direction. The third surface 23 includes a position overlapping with the ultrasonic oscillators 30 when viewed in the Z-axis direction. The third surface 23 includes a surface disposed directly below the multiple ultrasonic oscillators 30.

[0020] [First distance H] As shown in FIG. 2, the distance between the first plane 12 and the second plane 22 is a first distance H in the Z-axis direction.

[0021] [Second distance H23] In the Z-axis direction, the distance between the ultrasonic oscillator 31 and the third surface 23 is a second distance H23. The second distance H23 is longer than the first distance H. The second distance H23 is the distance from the ultrasonic oscillator 31 to a position P23a directly below the ultrasonic oscillator 31 as viewed in the Z-axis direction. The position P23a directly below is a position on the third surface 23.

[0022] [Arrangement of ultrasonic oscillators 31 to 34] Next, the arrangement of the ultrasonic oscillators 31 to 34 will be described with reference to Figure 3. The ultrasonic oscillators 31 and 32 are arranged apart in the X-axis direction. The ultrasonic oscillators 33 and 34 are arranged apart in the Y-axis direction. When viewed in the Z-axis direction, the ultrasonic oscillators 31 to 34 are arranged at positions corresponding to the vertices 14c of the imaginary square 14. When viewed in the Z-axis direction, the ultrasonic oscillators 31 to 34 are arranged outside the second plane 22. When viewed in the Z-axis direction, the ultrasonic oscillators 31 to 34 are arranged at positions overlapping with the third plane 23.

[0023] [Ultrasonic transmission and reception path] Next, the ultrasonic transmission and reception paths in the ultrasonic anemometer 100 will be described with reference to Figure 4. The ultrasonic anemometer 100 has diagonal transmission and reception paths UTx and UTy, and adjacent transmission and reception paths UTa, UTb, UTc, and UTd. The diagonal transmission and reception path UTx is a transmission and reception path between ultrasonic oscillator 31 and ultrasonic oscillator 32. When viewed in the Z-axis direction, the diagonal transmission and reception path UTx is formed along the X-axis direction. The diagonal transmission and reception path UTy is a transmission and reception path between ultrasonic oscillator 33 and ultrasonic oscillator 34. When viewed in the Z-axis direction, the diagonal transmission and reception path UTy is formed along the Y-axis direction.

[0024] The adjacent transmission / reception path UTa is a transmission / reception path between the ultrasonic oscillator 32 and the ultrasonic oscillator 33. The adjacent transmission / reception path UTb is a transmission / reception path between the ultrasonic oscillator 32 and the ultrasonic oscillator 34. The adjacent transmission / reception path UTc is a transmission / reception path between the ultrasonic oscillator 31 and the ultrasonic oscillator 34. The adjacent transmission / reception path UTd is a transmission / reception path between the ultrasonic oscillator 31 and the ultrasonic oscillator 33.

[0025] In the ultrasonic anemometer 100, as shown in FIG. 2, the first distance H, which is the distance between the first plane 12 and the second plane 22, is set so that the phase of the single reflected wave Uw1 matches the phase of the three reflected waves Uw3.

[0026] In the ultrasonic anemometer 100, the third surface 23 is formed so that the ultrasonic oscillator on the receiving side does not receive five reflected waves Uw5, seven reflected waves, nine reflected waves, or any more reflected waves.

[0027] The ultrasonic anemometer 100 can directly acquire vectors Vx and Vy on the diagonal transmission / reception paths UTx and UTy. This allows the ultrasonic anemometer 100 to detect wind direction and speed with high accuracy. As shown in Fig. 4, the vector Vx is along the X-axis direction between the ultrasonic oscillators 31 and 32. The vector Vy is along the Y-axis direction between the ultrasonic oscillators 33 and 34.

[0028] The ultrasonic anemometer 100 can acquire vectors Va, Vb, Vc, and Vd on adjacent transmission / reception paths UTa, UTb, UTc, and UTd. The ultrasonic anemometer 100 can calculate vectors Vx and Vy from vectors Va, Vb, Vc, and Vd. The ultrasonic anemometer 100 can avoid determining that there is no wind when there is strong wind across phases by comparing vectors Vx and Vy acquired directly from diagonal transmission / reception paths UTx and UTy with vectors Vx and Vy acquired from adjacent transmission / reception paths UTa, UTb, UTc, and UTd.

[0029] [One reflected wave] For example, in the diagonal transmission / reception path UTx, a single reflected wave Uw1 is transmitted from the ultrasonic oscillator 31, reflected at a point P22a on the second plane 22, and received by the ultrasonic oscillator 32. In Fig. 2, the single reflected wave Uw1 is indicated by a solid line.

[0030] [Three reflected waves] For example, in the diagonal transmission / reception path UTx, three reflected waves Uw3 are transmitted from the ultrasonic oscillator 31, reflected at point P22b on the second plane 22, reflected at point P12a on the first plane 12, reflected at point P22c on the second plane 22, and received by the ultrasonic oscillator 32. In Fig. 2, the three reflected waves Uw3 are indicated by dashed lines.

[0031] When it is desired to obtain one reflected wave Uw1 and three reflected waves Uw3 in the ultrasonic anemometer 100, once the distance between the ultrasonic oscillator 31 and the ultrasonic oscillator 32 is determined, the first distance H between the top plate 11 and the second plane 22 is determined.

[0032] [More than 5 reflected waves] For example, five reflected waves Uw5 are transmitted from the ultrasonic oscillator 31, reflected at point P23b on the third surface 23, and head toward the outside of the ultrasonic anemometer 100. The five reflected waves do not hit the top plate 11 after being reflected by the third surface 23. Five or more reflected waves head toward the outside of the ultrasonic anemometer 100 after being reflected by the third surface 23 and do not hit the top plate 11. In FIG. 2, the five reflected waves Uw5 are indicated by dashed lines. As will be described later, the five reflected waves include reflected waves that are reflected five times and reach the ultrasonic oscillator 32, and also include reflected waves that reach the ultrasonic oscillator 32 if a plane is formed at the same height position (position in the Z-axis direction) as the second plane 22. FIG. 2 illustrates five reflected waves Uw5 that do not reach the ultrasonic oscillator 32, while FIG. 7 illustrates reflected waves Uw5 that reach the ultrasonic oscillator 32.

[0033] Fig. 7 is a schematic cross-sectional view illustrating an ultrasonic anemometer 100D according to a comparative example. The ultrasonic anemometer 100D according to the comparative example shown in Fig. 7 differs from the ultrasonic anemometer 100 according to the first embodiment shown in Fig. 2 in that the area of ​​the second flat surface 22D is large, and ultrasonic waves that are reflected five or more times between the first flat surface 12 of the top panel 11 and the second flat surface 22D of the reflecting plate 21 (reflected wave Uw5) reach the ultrasonic oscillator 32.

[0034] For example, if the area of ​​the second plane 22D parallel to the first plane 12 is large and extends below the ultrasonic oscillators 31 and 32, the reflected wave Uw5 that is reflected five or more times between the first plane 12 and the second plane 22D will also reach the ultrasonic oscillator 32.

[0035] Here, if the propagation distance can be increased, that is, if the first distance H can be increased, ultrasonic waves that are reflected five or more times will be attenuated and will not reach the ultrasonic oscillator 32. However, if the ultrasonic anemometer is made smaller, the first distance H cannot be increased, and the reflected wave Uw5 that is reflected five or more times will also reach the ultrasonic oscillator 32. Therefore, the third surface 23 is set so that the reflected wave Uw5 that is reflected five or more times will be directed to the outside of the ultrasonic anemometer 100. In the ultrasonic anemometer 100, the area of ​​the second plane 22 parallel to the first plane 12 is made smaller than the second plane 22D so that the ultrasonic waves (reflected wave Uw5) do not reflect five or more times and reach the ultrasonic oscillator 32, and the third surface 23 (see FIGS. 1 and 2) is set so that the reflected wave Uw5 that is reflected five or more times will be directed to the outside of the ultrasonic anemometer 100.

[0036] 1 and 2 is required below the ultrasonic oscillator 31 at least in the Z-axis direction. In this embodiment, the third surface 23 is set so that five or more reflected waves Uw5 are directed toward the outside of the ultrasonic anemometer 100, but the third surface 23 may be set so that three or more reflected waves Uw3 are directed toward the outside of the ultrasonic anemometer 100.

[0037] In the ultrasonic anemometer 100, the first distance H between the top plate 11 and the second plane 22 and the distance between the ultrasonic oscillator 31 and the third plane 23 are appropriately set in the Z-axis direction, so that the diagonal transmission / reception paths UTx and UTy and the adjacent transmission / reception paths UTa, UTb, UTc, and UTd can be secured simultaneously.

[0038] [Distance between opposing sensors D1] The distance D1 between the opposing sensors may be the distance between the ultrasonic oscillator 31 and the ultrasonic oscillator 32. The distance D1 between the opposing sensors may be, for example, 23.3 mm.

[0039] [Distance between adjacent sensors D2] The distance D2 between adjacent sensors may be the distance between the ultrasonic oscillator 31 and the ultrasonic oscillator 33. The distance D2 between adjacent sensors may be, for example, 16.4 mm.

[0040] The first reflected wave and the third reflected wave have different measurement lines and different propagation distances, and therefore arrive at the receiving sensor with a propagation time difference. The receiving sensor is the ultrasonic oscillator 31-34 that receives the ultrasonic waves among the ultrasonic oscillators 31-34. In the ultrasonic anemometer 100, the first distance H is set so that the first reflected wave and the third reflected wave are in phase. If the first reflected wave and the third reflected wave are in opposite phase, the signal from the first reflected wave and the signal from the third reflected wave will cancel each other out, and no signal will be obtained.

[0041] [First distance H] The arrival time [s] of n reflected waves, the arrival distance [m] of n reflected waves, and the speed of sound [m / s] satisfy the following relationship. Arrival time of n reflected waves [s] = Arrival distance of n reflected waves [m] / Speed ​​of sound [m / s]

[0042] Here, the speed of sound c at 15 degrees is 340.65 [m / s].

[0043] The propagation distance A1 [m] of one reflected wave can be calculated using the following formula (1).

number

[0044] The propagation distance A3 [m] of the three reflected waves can be calculated using the following formula (2).

number

[0045] Here, when H in equations (1) and (2) is a variable, the difference between the arrival time of one reflected wave and the arrival time of three reflected waves fluctuates simultaneously.

[0046] For example, when the resonant frequency of the ultrasonic oscillators 31 to 34 is 40 kHz, one period is 25 μs. In the ultrasonic anemometer 100, the first distance H is set so that the difference between the arrival time of one reflected wave and the arrival time of three reflected waves is a multiple of 25 μs. With the ultrasonic anemometer 100 in which the distance between the first plane 12 and the second plane 22 is the first distance H, the one reflected wave and the three reflected waves can be set to be in positive phase.

[0047] For example, the first distance H may be 10.7 mm. When H = 10.7 mm is input into the above formulas (1) and (2) and the calculation is checked, the arrival time of one reflected wave is 92.65 μs, and the arrival time of three reflected waves is 142.91 μs. The difference between the arrival time of one reflected wave and the arrival time of three reflected waves is 50.26 μs, and the positive phase occurs with a delay of two periods.

[0048] By similar calculation, the optimum first distance H calculated using the distance D2 between adjacent sensors may be 9.9 mm.

[0049] To achieve both the diagonal transmission / reception paths UTx and UTy and the adjacent transmission / reception paths UTa, UTb, UTc, and UTd, the first distance H between the first plane 12 and the second plane 22 may be a value between 10.7 mm and 9.9 mm. To achieve both the diagonal transmission / reception paths UTx and UTy and the adjacent transmission / reception paths UTa, UTb, UTc, and UTd, the first distance H may be, for example, 10.3 mm. Here, positive phase does not necessarily mean that the wavelengths of the ultrasonic waves reaching the ultrasonic oscillator perfectly match, but also includes cases where the wavelengths are shifted by up to one-quarter. This is because at least the first reflected wave and the three reflected waves can be received without attenuation due to interference. Here, if the first distance is 10.3 mm, it can be said that the first reflected wave and the three reflected waves of the diagonal transmission / reception paths UTx and UTy and the adjacent transmission / reception paths UTa, UTb, UTc, and UTd are in positive phase. "Achieving both the diagonal transmission / reception paths UTx, UTy and the adjacent transmission / reception paths UTa, UTb, UTc, UTd" means that the reflected waves arrive once and three times on both the diagonal transmission / reception paths and the adjacent transmission / reception paths.

[0050] The optimal first distance H can also be applied to one, three, and five reflected waves. However, including up to five reflected waves places greater constraints on design. Therefore, the third surface 23 is set so that five or more reflected waves are directed to the outside of the ultrasonic anemometer 100. This makes it easier to determine the first distance H in the ultrasonic anemometer 100 than in the ultrasonic anemometer 100D according to the comparative example, in which five or more reflected waves reach the ultrasonic oscillator 32, thereby simplifying the design of the ultrasonic anemometer 100.

[0051] [Operation and effect of the ultrasonic anemometer 100 according to the first embodiment] The ultrasonic anemometer 100 according to the first embodiment includes a top plate 11 having a first plane 12 along the X-axis direction (first direction) and the Y-axis direction (second direction intersecting the first direction), an ultrasonic oscillator (first ultrasonic oscillator) 31 and an ultrasonic oscillator (second ultrasonic oscillator) 32 mounted on the top plate 11 and disposed at a predetermined distance from the first plane 12 in the X-axis direction, and a reflector 21 disposed opposite the first plane 12 in the Z-axis direction (third direction), having a second plane 22 parallel to the first plane 12 and a first distance H from the first plane 12, and having a third surface 23 that includes a position overlapping with the ultrasonic oscillator 31 in the Z-axis direction and is a second distance H23 longer than the first distance H from the ultrasonic oscillator 31 in the Z-axis direction. Note that "parallel" includes "approximately parallel."

[0052] In this acoustic transducer 100, ultrasonic waves transmitted from the ultrasonic oscillator 31 are reflected by the second plane 22 and reach the ultrasonic oscillator 32, thereby realizing a transmission / reception path with a single reflected wave. Furthermore, in the acoustic transducer 100, ultrasonic waves transmitted from the ultrasonic oscillator 31 are reflected by the second plane 22, and this reflected wave is reflected by the first plane 12, and then reflected again by the second plane 22 and reaches the ultrasonic oscillator 32, thereby realizing a transmission / reception path with three reflected waves. The first reflected wave and the third reflected wave have different measurement paths and different propagation distances, and therefore arrive at the receiving ultrasonic oscillators 31 and 32 with a time difference. The ultrasonic anemometer 100 can calculate the wind speed of the fluid to be measured using a round-trip path time difference (phase difference) evaluation. The ultrasonic anemometer 100 can be miniaturized and reduced in cost, and can receive ultrasonic waves by reflecting them multiple times.

[0053] In the ultrasonic anemometer 100, the third surface 23 is arranged opposite the ultrasonic oscillator 31 and the second ultrasonic oscillator 32 in the Z-axis direction and includes an inclined surface inclined relative to the second plane 22, and the inclined surface is inclined so as to face away from the second plane 22.

[0054] In the ultrasonic anemometer 100 configured as described above, the third surface 23 is formed as an inclined surface that is inclined so as to face away from the second plane 22, and thus a portion of the ultrasonic waves transmitted from the ultrasonic oscillator 32 is reflected by the third surface 23 and travels outside the ultrasonic anemometer 100. The ultrasonic anemometer 100 can realize an ultrasonic transmission and reception path that does not involve five reflected waves. The inclined surface may include a linear surface or a curved surface, for example, in a cross section along the Z-axis direction. The inclined surface may be any surface that allows the reflected waves reflected by the inclined surface to travel outside the ultrasonic anemometer 100.

[0055] The ultrasonic anemometer 100 further includes an ultrasonic oscillator (third ultrasonic oscillator) 33 and an ultrasonic oscillator (fourth ultrasonic oscillator) 34 mounted on the top plate 11 and arranged on both sides of the first plane 12 in the Y-axis direction, and the ultrasonic oscillators 31 to 34 are arranged at positions corresponding to the vertices 14c of the imaginary square 14 when viewed in the Z-axis direction, and the second plane 22 forms a circle when viewed in the Z-axis direction.

[0056] This ultrasonic anemometer 100 can realize a diagonal transmission / reception path UTx along the X-axis direction, a diagonal transmission / reception path UTy along the Y-axis direction, and adjacent transmission / reception paths UTa, UTb, UTc, and UTd along each side of an imaginary rectangle. The ultrasonic anemometer 100 can receive ultrasonic waves propagated along these transmission / reception paths and calculate a vector Vx along the X-axis direction, a vector Vy along the Y-axis direction, and vectors Va, Vb, Vc, and Vd along each side of the imaginary rectangle 14. The ultrasonic anemometer 100 can measure the wind direction and speed of the fluid being measured using these vectors Vx, Vy, Va, Vb, Vc, and Vd.

[0057] Furthermore, in the ultrasonic anemometer 100, the following equations (3) and (4) are satisfied when the first distance is H, the distance between the ultrasonic oscillators 31 and 32 is D1, and one cycle of the ultrasonic waves transmitted from the ultrasonic oscillators 31 and 32 is L. Here, the reason why one cycle L in equation (4) has a certain width is that a positive phase does not mean that the wavelengths of the ultrasonic waves reaching the ultrasonic oscillators are perfectly the same, but also includes cases where the wavelengths are shifted by up to 1 / 4.

number

number

[0058] The ultrasonic anemometer 100 further includes an ultrasonic oscillator 33 and an ultrasonic oscillator 34 mounted on the top panel 11 and arranged on both sides of the first plane 12 in the Y-axis direction, and satisfies the following equations (5) and (6) when the distance between the ultrasonic oscillator 31 and the third ultrasonic oscillator 34 is D2. Here, the reason why one period L in equation (6) has a width is that a positive phase does not mean that the wavelengths of the ultrasonic waves reaching the ultrasonic oscillators are perfectly the same, but also includes cases where the wavelengths are shifted by up to 1 / 4.

number

number

[0059] [Ultrasonic anemometer 100B according to the second embodiment] Next, an ultrasonic anemometer 100B according to a second embodiment will be described. Fig. 5 is a plan view showing the arrangement of the reflector 21B and ultrasonic oscillators 31 to 34 of the ultrasonic anemometer 100B according to the second embodiment. The ultrasonic anemometer 100B shown in Fig. 5 differs from the ultrasonic anemometer 100 shown in Fig. 3 in that it includes a reflector 21B instead of the reflector 21, and that the shape of the second plane 22B is different. Note that in the description of 100B according to the second embodiment, descriptions that are the same as those for the ultrasonic anemometer 100 according to the first embodiment may be omitted.

[0060] The ultrasonic anemometer 100B includes a reflector 21B, and a second plane 22B is formed on the reflector 21B. The second plane 22B is formed to form a cross shape when viewed in the Z-axis direction. The second plane 22B includes regions 24a, 24b, 24c, 24d, and 24e. The region 24a is rectangular and is located at the center of the second plane 22B. The diagonals of the region 24a are arranged along the X-axis direction and the Y-axis direction. The regions 24b to 24e are rectangular and are formed to extend outward from each side of the region 24a. For example, the region 24b is formed between the ultrasonic oscillator 32 and the ultrasonic oscillator 34. The region 24c is formed between the ultrasonic oscillator 32 and the ultrasonic oscillator 33. The region 24d is formed between the ultrasonic oscillator 33 and the ultrasonic oscillator 31. The region 24e is formed between the ultrasonic oscillator 31 and the ultrasonic oscillator .

[0061] The ultrasonic anemometer 100B according to the second embodiment also achieves the same effects as the ultrasonic anemometer 100 according to the first embodiment. Furthermore, the adjacent transmission / reception paths UTa, UTb, UTc, and UTd can reflect ultrasonic waves from their outwardly protruding portions. As a result, the wind speed can be calculated using not only the transmission / reception paths UTx and Uty but also the transmission / reception paths UTa, UTb, UTc, and UTd, thereby improving the accuracy of the wind speed. The second plane 22B may be shaped like a cross.

[0062] [Ultrasonic anemometer 100C according to the third embodiment] Next, an ultrasonic anemometer 100C according to a third embodiment will be described. Fig. 6 is a plan view showing the arrangement of the reflector 21C and ultrasonic oscillators 31 to 34 of the ultrasonic anemometer 100C according to the third embodiment. The ultrasonic anemometer 100C shown in Fig. 6 differs from the ultrasonic anemometer 100 shown in Fig. 3 in that it includes a reflector 21C instead of the reflector 21, and that the shape of the second plane 22C is different. Note that in the description of 100C according to the third embodiment, descriptions that are the same as those of the ultrasonic anemometers 100 and 100B according to the above embodiments may be omitted.

[0063] The ultrasonic anemometer 100C includes a reflector 21C, and a second plane 22C is formed on the reflector 21C. The second plane 22C is formed to have a cross shape (approximately a cross shape) when viewed in the Z-axis direction. The second plane 22C includes regions 24a, 24b, 24c, 24d, and 24e. The region 24a is rectangular and is located at the center of the second plane 22C. The diagonals of the region 24a are arranged along the X-axis direction and the Y-axis direction. The regions 24b to 24e are semicircular and are formed to extend outward from each side of the region 24a. For example, the region 24b is formed between the ultrasonic oscillator 32 and the ultrasonic oscillator 34. The region 24c is formed between the ultrasonic oscillator 32 and the ultrasonic oscillator 33. The region 24d is formed between the ultrasonic oscillator 33 and the ultrasonic oscillator 31. The region 24e is formed between the ultrasonic oscillator 31 and the ultrasonic oscillator 34. The second plane 22C is an example of a cross shape with an arc-shaped tip.

[0064] The ultrasonic anemometer 100C according to the third embodiment also achieves the same effects as the ultrasonic anemometers 100 according to the first and second embodiments. The shapes of the regions 24b to 24e are not limited to semicircular shapes, and may be semi-elliptical, trapezoidal, or other shapes. It is sufficient that there is at least a second plane 22 between adjacent ultrasonic oscillators, and by making the other portions the third plane 23, unnecessary reflections can be reduced, thereby reducing noise.

[0065] [Ultrasonic anemometer 100D according to the fourth embodiment] Next, an ultrasonic anemometer 100D according to a fourth embodiment will be described. Fig. 8 is a plan view showing the arrangement of the reflector 21D and the ultrasonic oscillators 31 to 34 of the ultrasonic anemometer 100D according to the fourth embodiment. The ultrasonic anemometer 100D shown in Fig. 8 differs from the ultrasonic anemometer 100 shown in Fig. 3 in that it includes a reflector 21D instead of the reflector 21, and that a part of the second plane 22D is disposed directly below the ultrasonic oscillators 31 to 34 when viewed in the Z-axis direction. Note that in the description of 100D according to the fourth embodiment, descriptions that are the same as those for the ultrasonic anemometer 100 according to the above embodiments may be omitted.

[0066] The ultrasonic anemometer 100D includes a reflector 21D, and a second plane 22D is formed on the reflector 21D. The second plane 22D is formed to have a circular shape when viewed in the Z-axis direction. In the Z-axis direction, at least a portion of the second plane 22D is disposed directly below the ultrasonic oscillators 31 to 34. In the Z-axis direction, a portion of the second plane 22D near the outer periphery is disposed so as to overlap with the ultrasonic oscillators 31 to 34.

[0067] The ultrasonic anemometer 100D according to the fourth embodiment also achieves the same effects as the ultrasonic anemometer 100 according to the above embodiment. A portion of the second plane 22D may be disposed directly below the ultrasonic oscillators 31 to 34. As a result, the range of the second plane 22D within which ultrasonic waves transmitted from the ultrasonic oscillator 30 can be reflected the first time can be widened. For example, in order for ultrasonic waves reflected three times to reach the ultrasonic oscillator 31 and the ultrasonic oscillator 34, the second plane 22D must be located at a position one-quarter of the distance D2 between adjacent sensors. However, there is a limit to how small the ultrasonic oscillator 30 can be. Therefore, by disposing a portion of the second plane 22D directly below the ultrasonic oscillator 30, the distance D2 between adjacent sensors can be shortened, thereby enabling the ultrasonic anemometer 100D to be made smaller.

[0068] [Ultrasonic anemometer 100E according to the fifth embodiment] Next, an ultrasonic anemometer 100E according to a fifth embodiment will be described. Fig. 9 is a plan view showing the arrangement of the reflector 21E and ultrasonic oscillators 31 to 34 of the ultrasonic anemometer 100E according to the fifth embodiment. The ultrasonic anemometer 100D shown in Fig. 9 differs from the ultrasonic anemometer 100 shown in Fig. 3 in that a reflector 21E is provided instead of the reflector 21, and the shape of the second plane 22E is different. A part of the second plane 22E is disposed directly below the ultrasonic oscillators 31 to 34. In the description of 100E according to the fifth embodiment, descriptions that are the same as those for the ultrasonic anemometer 100 according to the above embodiments may be omitted.

[0069] The ultrasonic anemometer 100E includes a reflector 21E, and a second plane 22E is formed on the reflector 21E. The second plane 22E is formed to form a cross shape when viewed in the Z-axis direction. The second plane 22E includes regions 24a, 24b, 24c, 24d, and 24e. The region 24a is rectangular and is located at the center of the second plane 22E. The diagonals of the region 24a are arranged along the X-axis direction and the Y-axis direction. The regions 24b to 24e are rectangular and are formed to extend outward from each side of the region 24a. For example, the region 24b is formed between the ultrasonic oscillator 32 and the ultrasonic oscillator 34. The region 24c is formed between the ultrasonic oscillator 32 and the ultrasonic oscillator 33. The region 24d is formed between the ultrasonic oscillator 33 and the ultrasonic oscillator 31. The region 24e is formed between the ultrasonic oscillator 31 and the ultrasonic oscillator 34. The region 24a is an example of a first region, and the regions 24b to 24e are examples of a second region.

[0070] In the Z-axis direction, at least a portion of the second plane 22E is disposed directly below the ultrasonic oscillators 31 to 34. In the Z-axis direction, a portion of the second plane 22E is disposed so as to overlap with the ultrasonic oscillators 31 to 34.

[0071] Parts of regions 24a, 24d, and 24e are disposed directly below ultrasonic oscillator 31. Parts of regions 24a, 24b, and 24c are disposed directly below ultrasonic oscillator 32. Parts of regions 24a, 24c, and 24d are disposed directly below ultrasonic oscillator 33. Parts of regions 24a, 24b, and 24e are disposed directly below ultrasonic oscillator 34. In the Z-axis direction, at least a part of second plane 22E is disposed so as to overlap ultrasonic oscillators 31 to 34.

[0072] The ultrasonic anemometer 100E according to the fifth embodiment also achieves the same effects as the ultrasonic anemometer 100 according to the above embodiments. A portion of the second plane 22E may be disposed directly below the ultrasonic oscillators 31 to 34. As a result, the range of the second plane 22E on which ultrasonic waves transmitted from the ultrasonic oscillator 30 can be reflected the first time can be widened, even in adjacent transmission / reception paths. For example, in order for three reflected waves of ultrasonic waves to reach the ultrasonic oscillator 31 and the ultrasonic oscillator 34, the second plane 22E must be located at a position ¼ of the distance D2 between adjacent sensors. However, there is a limit to how small the ultrasonic oscillator 30 can be. Therefore, by disposing a portion of the second plane 22E directly below the ultrasonic oscillator 30, the distance D2 between adjacent sensors can be shortened, thereby enabling the ultrasonic anemometer 100E to be miniaturized. The tip of the cross-shaped second plane 22E may be arc-shaped, as shown in FIG. 6.

[0073] [First Slope 25] Furthermore, the reflector 21E may have a first inclined surface 25 formed around the second flat surface 22E and inclined relative to the second flat surface 22E. The first inclined surface 25 is inclined outward so as to face the opposite side from the second flat surface 22E. Furthermore, the surface of the first inclined surface 25 may be subjected to an anti-reflection treatment to suppress reflection of ultrasonic waves. An example of the anti-reflection treatment is a textured surface. A portion of the first inclined surface 25 is disposed directly below the ultrasonic oscillators 31 to 34.

[0074] [Side 3 23] The third surface 23 is formed around the second plane 22E and the first inclined surface 25 when viewed in the Z-axis direction. The third surface 23 is formed to surround the second plane 22E and the first inclined surface 25. The third surface 23 is an example of a second inclined surface. The third surface 23 is inclined at an angle different from that of the first inclined surface 25. If the first inclined surface 25 were not present and a vertical portion were formed at the boundary between the second plane 22E and the third surface 23, turbulence would occur, making it impossible to accurately measure wind speed. Therefore, by providing the third surface 23 with an inclination different from that of the first inclined surface 25, it is possible to ensure the required size for the second plane 22E while ensuring the calculated optimal first distance H, and to minimize the size of the ultrasonic anemometer 100E. A portion of the third surface 23 is located directly below the ultrasonic oscillators 31 to 34. The ultrasonic anemometer 100D according to the fourth embodiment may also have a first inclined surface between the second plane 22D and the third surface 23.

[0075] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0076] 100, 100B, 100C, 100D, 100E: ultrasonic anemometer, 11: top plate, 12: first plane, 21, 21B, 21C, 21D, 21E: reflectors, 22, 22B, 22C, 22D, 22E: second plane, 23: third plane (second inclined surface), 24a: area (first area), 24b to 24e: second area, 25: first inclined surface, 30: multiple ultrasonic oscillators, 31: ultrasonic oscillator (first ultrasonic oscillator), 32: ultrasonic oscillator (second ultrasonic oscillator), 33: ultrasonic oscillator (third ultrasonic oscillator), 34: ultrasonic oscillator (fourth ultrasonic oscillator), X: X-axis direction (first direction), Y: Y-axis direction (second direction), Z: Z-axis direction (third direction).

Claims

1. a top plate having a first plane along a first direction and a second direction intersecting the first direction; a first ultrasonic oscillator and a second ultrasonic oscillator mounted on the top plate and arranged at a predetermined distance from each other on the first plane in the first direction; a reflector disposed opposite the first plane in a third direction intersecting the first direction and the second direction, the reflector having a first distance from the first plane, a second plane parallel to the first plane, and the reflector having a third surface that includes a position overlapping with a first ultrasonic oscillator in the third direction and is a second distance from the first ultrasonic oscillator in the third direction that is longer than the first distance.

2. the third surface is disposed opposite the first ultrasonic oscillator and the second ultrasonic oscillator in the third direction and includes an inclined surface inclined with respect to the second plane, The ultrasonic anemometer according to claim 1 , wherein the inclined surface is inclined so as to face away from the second plane.

3. a third ultrasonic oscillator and a fourth ultrasonic oscillator mounted on the top plate and disposed on both sides of the first plane in the second direction; the first ultrasonic oscillator, the second ultrasonic oscillator, the third ultrasonic oscillator, and the third ultrasonic oscillator are arranged at positions corresponding to vertices of a square when viewed in the third direction, The ultrasonic anemometer according to claim 1 or 2, wherein the second plane is circular when viewed in the third direction.

4. a third ultrasonic oscillator and a fourth ultrasonic oscillator mounted on the top plate and disposed on both sides of the first plane in the second direction; the first ultrasonic oscillator, the second ultrasonic oscillator, the third ultrasonic oscillator, and the third ultrasonic oscillator are arranged at positions corresponding to vertices of a square when viewed in the third direction, The ultrasonic anemometer according to claim 1 , wherein the second plane has a cross shape when viewed in the third direction.

5. a third ultrasonic oscillator and a fourth ultrasonic oscillator mounted on the top plate and disposed on both sides of the first plane in the second direction; the first ultrasonic oscillator, the second ultrasonic oscillator, the third ultrasonic oscillator, and the third ultrasonic oscillator are arranged at positions corresponding to vertices of a square when viewed in the third direction, 2. The ultrasonic anemometer according to claim 1, wherein the second plane has a cross shape when viewed in the third direction, and a tip of the cross shape has an arc shape.

6. The first distance is H, The distance between the first ultrasonic oscillator and the second ultrasonic oscillator is D1, When one period of the ultrasonic waves transmitted from the first ultrasonic oscillator and the second ultrasonic oscillator is L, the following expressions (1) and (2) are satisfied: [Equation 1] [Equation 2] 3. The ultrasonic anemometer according to claim 1 or 2.

7. a third ultrasonic oscillator and a fourth ultrasonic oscillator mounted on the top plate and disposed on both sides of the first plane in the second direction; When the distance between the first ultrasonic oscillator and the third ultrasonic oscillator is D2, the following formulas (3) and (4) are satisfied: [Equation 3] [Equation 4] 7. The ultrasonic anemometer according to claim 6.

8. 2. The ultrasonic anemometer according to claim 1, wherein at least a part of the second plane is disposed directly below the first ultrasonic oscillator and the second ultrasonic oscillator in the third direction.

9. The second plane of the cross shape is a rectangular first region disposed in the center; a plurality of second regions extending from each side of the first region; 6. The ultrasonic anemometer according to claim 4, wherein at least a portion of the second region is disposed directly below the first ultrasonic oscillator, the second ultrasonic oscillator, the third ultrasonic oscillator, and the fourth ultrasonic oscillator in the third direction.

10. the reflector has a first inclined surface formed around the second plane and inclined with respect to the second plane, the third surface includes a second inclined surface formed outside the first inclined surface and inclined at an angle different from that of the first inclined surface with respect to the second plane, the first inclined surface and the second inclined surface are inclined so as to face a side opposite to the second plane, 10. The ultrasonic anemometer according to claim 9, wherein the first inclined surface is subjected to an anti-reflection treatment for suppressing reflection of ultrasonic waves.

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