Ultrasonic anemometer

Abstract

The present invention suppresses the influence of raindrops on a measurement result. An ultrasonic anemometer 100 comprises an upper frame 10 on which an ultrasonic transceiver 30 is mounted, and a lower frame 20 arranged at a prescribed distance from the upper frame 10 in a first direction (Z-axis direction). An inclined part 45 that extends in a second direction (X-axis direction) intersecting the first direction when viewed in the first direction is formed on the outer edge of the upper frame 10.

Description

ultrasonic anemometer

[0001] The present disclosure relates to ultrasonic anemometers.

[0002] For example, a weather meter equipped with multiple sensors for observing meteorological elements is known (see, for example, Patent Document 1). The weather meter described in Patent Document 1 includes a first unit, a second unit, a third unit, and a fourth unit. A raindrop sensor and a sunshine sensor are provided on the roof of the first unit. The second unit is attached below the first unit via a support. An ultrasonic wind direction and speed sensor is provided on the top surface of the second unit, and a barometric pressure sensor is disposed inside the second unit. The third unit is disposed below the second unit and houses a temperature sensor and a barometric pressure sensor. The fourth unit has a ventilator disposed to surround the third unit.

[0003] JP 2015-210132 A

[0004] Conventional technology has room for improvement in terms of the effects of raindrops.

[0005] The present disclosure provides an ultrasonic anemometer that can suppress the influence of raindrops on measurement results.

[0006] The ultrasonic anemometer of the present disclosure comprises an upper body on which an ultrasonic transmitter / receiver is mounted, and a lower body arranged a predetermined distance in a first direction from the upper body, and the outer edge of the upper body is formed with an inclined portion that extends in a second direction that intersects the first direction when viewed in the first direction.

[0007] The present disclosure can provide an ultrasonic anemometer that can suppress the influence of raindrops on measurement results.

[0008] 1 is a schematic perspective view illustrating an ultrasonic anemometer according to a first embodiment. FIG. 2 is a schematic plan view illustrating an ultrasonic anemometer according to the first embodiment. FIG. 3 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to the first embodiment, taken along the X-Z plane. FIG. 4 is a partially enlarged cross-sectional view illustrating an umbrella portion and a cavity portion of the ultrasonic anemometer according to the first embodiment. FIG. 5 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to a second embodiment. FIG. 6 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to a third embodiment, taken along the X-Z plane. FIG. 7 is a bottom view illustrating the bottom surface of an upper body and the bottom surface of a shielding plate of the ultrasonic anemometer according to the third embodiment. FIG. 8 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of the ultrasonic anemometer according to the third embodiment. FIG. 9 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to a comparative example, taken along the X-Z plane. FIG. 10 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of the ultrasonic anemometer according to the first modification. 10A and 10B are enlarged partial cross-sectional views illustrating an umbrella portion, a cavity portion, and a shielding plate of an ultrasonic anemometer according to a modified example 3. FIG. 10B are enlarged partial cross-sectional views illustrating an umbrella portion, a cavity portion, and a shielding plate of an ultrasonic anemometer according to a modified example 4.

[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. Furthermore, in this specification, the terms "upper" and "lower" may be used. These refer to the "upper" and "lower" states shown in FIGS. 1 and 3, and in the Z-axis direction, the side where the upper body 10 is located is referred to as "upper," and the side where the lower body 20 is located is referred to as "lower."

[0010] [Ultrasonic Anemometer 100 According to the First Embodiment] FIG. 1 is a schematic perspective view illustrating the ultrasonic anemometer 100 according to the first embodiment. FIG. 2 is a schematic plan view illustrating the ultrasonic anemometer 100 according to the first embodiment. FIG. 3 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100 according to the first embodiment, taken along the X-Z plane. FIG. 4 is a partially enlarged cross-sectional view illustrating the umbrella portion and cavity portion of the ultrasonic anemometer according to the first embodiment. Note that in each figure, the X-axis direction, Y-axis direction, and Z-axis direction, which are orthogonal to each other, may be illustrated. The X-axis direction, Y-axis direction, and Z-axis direction do not have to be orthogonal to each other. The X-axis direction, Y-axis direction, and Z-axis direction may be any direction. The Z-axis direction is an example of a first direction. The X-axis direction is an example of a second direction intersecting the first direction. The Y-axis direction is an example of a third direction intersecting the first direction and the second direction. The X-axis direction and Y-axis direction may be reversed.

[0011] 1 to 3 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 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] 1 and 2 , the ultrasonic anemometer 100 includes an upper body 10, a lower body 20, and multiple support columns 13. The upper body 10 and the lower body 20 are spaced apart in the Z-axis direction. The multiple support columns 13 extend in the Z-axis direction and support the upper body 10 relative to the lower body 20. The lower ends of the support columns 13 are fixed to the lower body 20, and the upper ends of the support columns 13 are fixed to the upper body 10. The upper body 10 is equipped with multiple ultrasonic transmitters / receivers 30 and a circuit board. Four ultrasonic transmitters / receivers 30 are arranged on the upper body 10. The ultrasonic transmitters / receivers 30 are arranged at the vertices of a substantially square.

[0013] As shown in FIGS. 2 and 3, the ultrasonic anemometer 100 includes a top plate 11, a plurality of (for example, four) ultrasonic transmitters / receivers 30, and a reflector 21.

[0014] [Upper Body 10] As shown in Figures 3 and 4, the upper body 10 has a main body 15 and an umbrella portion 40. The main body 15 includes a top plate 11. The main body 15 is equipped with multiple ultrasonic transceivers 30. The top plate 11 is disposed at the bottom of the main body 15. The top plate 11 is, for example, disk-shaped. The multiple ultrasonic transceivers 30 are held to the main body 15 by holders 19 shown in Figure 4. Here, the main body 15 includes a portion where the ultrasonic transceivers 30 are disposed. A housing portion may be formed inside the main body 15 to house a wiring board or the like connected to the ultrasonic transceivers 30. The portion of the upper body 10 inside the line L15 shown in Figure 3 is the main body 15. The line L15 is a line extending in the Z-axis direction from the side surface 15a of the main body 15 exposed by the cavity portion 50. It can also be said to be a line extending in the Z-axis direction from the portion where the shielding plate 60 and the side surface 15a meet.

[0015] The upper body 10 holds the ultrasonic transceiver 30 so that the bottom surface 30b of the ultrasonic transceiver 30 is exposed. The ultrasonic transceiver 30 is held by the top plate 11, and the bottom surface 30b is exposed downward. The umbrella portion 40 will be described later.

[0016] [First 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 lower surface of the top plate 11.

[0017] [Multiple Ultrasonic Transceivers 30] As shown in Fig. 2, the multiple ultrasonic transceivers 30 include ultrasonic transceivers 31 to 34. The ultrasonic anemometer 100 may include three or more ultrasonic transceivers 30. The ultrasonic transceiver 30 is an ultrasonic transmitting unit that transmits ultrasonic waves and an ultrasonic receiving unit that receives ultrasonic waves. The ultrasonic transceiver 31 and the ultrasonic transceiver 32 are positioned apart in the X-axis direction. The ultrasonic transceiver 33 and the ultrasonic transceiver 34 are positioned apart in the Y-axis direction.

[0018] [Lower Body 20] The lower body 20 has a reflector 21 as shown in Fig. 3. The lower body 20 is disposed at a predetermined distance from the upper body 10 in the Z-axis direction. A flow path 101 is formed between the upper body 10 and the lower body 20.

[0019] [Reflector 21] The reflector 21 is provided on the upper part of the lower body 20. The reflector 21 is disposed so as to face the top plate 11 in the Z-axis direction. A flow path 101 is formed between the top plate 11 and the reflector 21, through which the fluid to be measured can pass. The fluid to be measured may be, for example, air. The reflector 21 has a surface that reflects ultrasonic waves transmitted from the ultrasonic transceiver 30. The ultrasonic waves are emitted into the flow path 101 from the bottom surface 30b of the ultrasonic transceiver 30.

[0020] [Second Plane 22] The reflector 21 has a second plane 22. The second plane 22 may be the upper surface of the reflector 21. The second plane 22 is a plane that faces the first plane 12 in the Z-axis direction and is parallel to the second plane 22. The second plane 22 is a plane that extends along the X-axis direction and the Y-axis direction. 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 that overlaps with the first plane 12. The second plane 22 may be formed in the center of the reflector 21, or may be formed on the entire surface of the reflector 21.

[0021] [Third Surface 23] The reflector 21 has a third surface 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 to surround the second plane 22. The third surface 23 may be, for example, a conical slope. 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 in the X-axis direction than the lower end of the third surface 23. In the Z-axis direction, the lower end of the third surface 23 is located further outward than the upper end of the third surface 23. The third surface 23 is inclined outward so as to face the opposite side to the second plane 22. The outer end of the third surface 23 is located lower than the inner end. "Outward" may also mean that the outer end is located lower than the inner end. "Downward" refers to the direction away from the top plate 11 in the Z-axis direction. The third surface 23 includes a position overlapping with the ultrasonic transceivers 30 when viewed in the Z-axis direction. The third surface 23 includes a surface disposed directly below the ultrasonic transceivers 30. The reflecting plate 21 may have only the second plane surface 22 and may not have the third surface 23.

[0022] [Reflected Wave] Ultrasonic waves transmitted from the ultrasonic transceiver 30 on the transmitting side are reflected by the second plane 22 and received by the ultrasonic transceiver 30 on the receiving side.

[0023] 3 and 4, the umbrella portion 40 is formed to surround the main body 15. The umbrella portion 40 is formed along the outer periphery of the main body 15. The umbrella portion 40 is an example of an inclined portion. The umbrella portion 40 has an annular shape when viewed in the Z-axis direction. The outer surface of the umbrella portion 40 forms an inclined surface 41.

[0024] As shown in FIG. 3 , the lower portion of the umbrella portion 40 is formed to extend in the X-axis direction. Furthermore, as shown in FIG. 1 , when viewing the ultrasonic anemometer 100 as a whole, the lower portion of the umbrella portion 40 is formed to extend in the radial direction of the upper body 10. The radial direction of the upper body 10 is a direction intersecting the center line CL1 of the upper body 10 and includes the X-axis direction and the Y-axis direction. The radial direction may also be the radial direction of a virtual circle centered on the center line CL1 of the upper body 10 shown in FIG. 1 . The inclined surface 41 is inclined so that the lower side of the inclined surface 41 is positioned outward in the radial direction of the upper body 10 compared to the upper side of the inclined surface 41. The lower side of the inclined surface 41 is positioned outward in the radial direction of the upper body 10 compared to the upper side of the inclined surface 41.

[0025] The maximum outer diameter of the umbrella portion 40 is larger than the outer diameter of the reflector 21. In the X-axis direction, the tip 40a of the umbrella portion 40 is disposed radially outward from the end 20a of the upper surface of the reflector 21.

[0026] The umbrella portion 40 includes a plate-shaped portion, and the thickness direction of the plate-shaped portion of the umbrella portion 40 is a direction inclined with respect to the X-axis direction and the Z-axis direction on the XZ plane shown in FIG.

[0027] [Hollow Portion 50] As shown in Figures 3 and 4, a hollow portion 50 is formed in the upper body 10. The hollow portion 50 is formed between the main body 15 and the umbrella portion 40 in the radial direction of the upper body 10. The hollow portion 50 is formed inside the umbrella portion 40 in the radial direction of the upper body 10. The hollow portion 50 is a recessed portion recessed upward. The hollow portion 50 is formed around the entire circumference of the umbrella portion 40. The hollow portion 50 is formed between the side surface 15a of the main body 15 and the inner surface 43 of the umbrella portion 40. The "inside" refers to the side closer to the center line CL1 of the upper body 10 shown in Figure 3. The "outside" refers to the side farther from the center line CL1 of the upper body 10.

[0028] [Corner 16a at the bottom of main body 15 of upper body 10] As shown in Figures 3 and 4, the bottom of the upper body 10 has a corner 16a that is located more inward than the umbrella portion 40 in the X-axis direction. The bottom of the upper body 10 includes the first flat surface 12 of the top plate 11. The corner 16a may be an end of the first flat surface 12. The corner 16a may be a lower end of the side surface 15a of the main body 15. The corner 16a includes a surface that contacts the hollow portion 50. The corner 16a may also include a surface that contacts the flow path 101. In a cross section along the Z-axis direction, the corner 16a is rounded. The corner 16a includes a curved surface. The corner 16a is formed around the entire circumference of the main body 15.

[0029] [Recess 17] As shown in FIG. 4 , a recess 17 is formed in the bottom of the main body 15. The recess 17 is a groove recessed above the first plane 12. The recess 17 is formed in an annular shape when viewed in the Z-axis direction. The recess 17 is located inside the corner 16a. The recess 17 is located outside the multiple ultrasonic transceivers 30. The recess 17 is located so as to surround the multiple ultrasonic transceivers 30. In other words, the multiple ultrasonic transceivers 30 are located inside the annular recess 17. In the radial direction, a convex portion 18 is formed between the ultrasonic transceiver 30 and the recess 17, protruding toward the flow path 101 more than the bottom surface 30b of the ultrasonic transceiver 30. The recess 17 may be formed at a position higher than the bottom surface 30b of the ultrasonic transceiver 30 in the Z-axis direction, or may be formed at the same height as the bottom surface 30b.

[0030] [Tilt Angle θ1 of Inclined Surface 41 of Umbrella Section 40] The lower part of the umbrella section 40 has an inclined surface 41 having an inclination angle θ1 with respect to the first plane (XY plane, horizontal plane) 12. The inclination angle θ1 of the inclined surface 41 of the umbrella section 40 is an angle set so that the kinetic energy of the raindrops 110 falling on the inclined surface 41 is greater than the surface tension energy of the raindrops 110 adhering to the inclined surface 41. The inclination angle θ1 may be, for example, 65 degrees. The inclination angle θ1 shown in FIG. 4 is the angle between a line along the X-axis and a line along the inclined surface 41.

[0031] [First and second parts of upper body 10] The upper body 10 may have a first part and a second part. The first part is, for example, the main body 15. The second part is the umbrella part 40. The main body 15 and the umbrella part 40 are formed, for example, as a single unit. The main body 15 is formed, for example, in a cylindrical shape. The umbrella part 40 forms, for example, a conical surface. The umbrella part 40 is connected to the main body 15 as shown in FIG. 4 . The main body 15 and the umbrella part 40 may be made of a material such as resin. The material of the main body 15 and the umbrella part 40 is not limited to resin and may be other materials.

[0032] The umbrella portion 40 may include a protruding piece 44 that protrudes radially from the side surface 15a of the main body 15, and an inclined portion 45 that extends diagonally downward from the protruding piece 44. The protruding piece 44 connects the main body 15 and the inclined portion 45. The thickness direction of the protruding piece 44 is along the Z-axis direction. The inclined portion 45 extends diagonally downward from the radially outer end of the protruding piece 44. The outer surface of the inclined portion 45 forms an inclined surface 41.

[0033] The umbrella portion 40, which is the second portion, may be formed integrally with the main body 15, which is the first portion, or may be formed as a separate member. The umbrella portion 40 may be configured to be detachable from the main body 15. The umbrella portion 40 may have a structure that allows it to be attached to and detached from the main body 15. The umbrella portion 40 may be attached to the main body 15 via another member, for example.

[0034] [Taper of Bottom 42 of Umbrella Portion 40] The bottom 42 of the umbrella portion 40 is tapered. The bottom 42 may be the bottom surface of the inclined portion 45. In the bottom 42 of the umbrella portion 40, the radially inner end 42a is positioned higher than the radially outer end (tip 40a). The end 42a may be the end where the bottom 42 intersects with the inner surface 43. The angle θ2 of the taper of the bottom 42 from the first plane 12 to the Z-axis direction may be, for example, 12.5 degrees. The bottom 42 of the umbrella portion 40 is tapered, and the end 42a is positioned higher than the tip 40a. This prevents raindrops 110 that adhere to and fall on the inclined surface 41 from entering the cavity 50 in the ultrasonic anemometer 100. The raindrops 110 are prevented from moving upward along the tapered bottom portion 42 , and the raindrops 110 are prevented from entering the cavity portion 50 .

[0035] [Operation and Effect of Ultrasonic Anemometer 100 According to First Embodiment] The ultrasonic anemometer 100 according to the first embodiment includes an upper body 10 on which an ultrasonic transceiver 30 is mounted so that the bottom surface 30b of the ultrasonic transceiver 30 is exposed, and a lower body 20 arranged a predetermined distance in the Z-axis direction (first direction) from the upper body 10. An inclined portion (umbrella portion 40) 45 is formed on the outer edge of the upper body 10, extending in the X-axis direction (second direction intersecting the first direction) when viewed in the Z-axis direction. The outer edge of the upper body 10 is the outer periphery of the upper body 10 when viewed in the Z-axis direction. The outer edge of the upper body 10 may also be the periphery of the upper body 10.

[0036] According to the ultrasonic anemometer 100, the umbrella portion 40 provided on the upper body 10 prevents raindrops 110 from entering the flow path 101. Also, the raindrops 110 are prevented from adhering to the bottom surface 30b of the ultrasonic transceiver 30. As a result, the ultrasonic anemometer 100 reduces the influence of the raindrops 110 on the measurement results obtained by the ultrasonic transceiver 30. The ultrasonic anemometer 100 reduces the influence of the raindrops 110 in rainy weather, improving the accuracy of measuring wind speed and wind direction.

[0037] In the ultrasonic anemometer 100, a cavity 50 is formed between the umbrella portion 40 and the ultrasonic transceiver 30 in the X-axis direction (second direction). In the ultrasonic anemometer 100, the inner surface 43 of the umbrella portion 40 is formed so as to form the cavity 50.

[0038] In the ultrasonic anemometer 100 configured as described above, the upwardly recessed cavity 50 is formed inside the umbrella portion 40, which prevents raindrops 110 that fall along the inclined surface 41 of the umbrella portion 40 from adhering to the bottom surface 30b of the ultrasonic transceiver 30. In the ultrasonic anemometer 100, the raindrops 110 are prevented from approaching the ultrasonic transceiver 30 through the cavity 50.

[0039] In the ultrasonic anemometer 100, the bottom surface of the upper body 10 includes a first plane 12 that is aligned with the X-axis direction and the Y-axis direction (a third direction intersecting the second direction), and the bottom 42 of the umbrella portion 40 is inclined so that the end 42a (tip 40a) farther from the center line CL1 (center) of the upper body 10 in the X-axis direction is positioned lower (closer to the lower body 20 in the Z-axis direction) than the end 42a (end portion) closer to the center line CL1. A taper θ2 that slopes outward in the X-axis direction is formed on the bottom 42 of the umbrella portion 40.

[0040] In the ultrasonic anemometer 100 having this configuration, the tapered bottom 42 of the umbrella portion 40 prevents raindrops 110 falling down the inclined surface 41 from entering the cavity 50. In the ultrasonic anemometer 100, adhesion of raindrops 110 to the bottom surface 30b of the ultrasonic transceiver 30 is prevented. In the ultrasonic anemometer 100, the influence of raindrops 110 on the measurement results obtained by the ultrasonic transceiver 30 is reduced.

[0041] In the ultrasonic anemometer 100, the bottom of the upper body 10 (the bottom of the main body 15) has a corner 16a that is located inside the umbrella portion 40 in the X-axis direction. A cavity 50 is formed between the corner 16a and the umbrella portion 40 in the X-axis direction, and the corner 16a formed on the bottom of the upper body 10 is rounded. The corner 16a includes a curved surface. The outer surface of the corner 16a may be rounded.

[0042] In the ultrasonic anemometer 100 having this configuration, the corners 16a of the upper body 10 that contact the flow path 101 are rounded, thereby suppressing the influence on the flow of air flowing through the flow path 101. In other words, turbulence can be prevented, and wind speed errors can be suppressed.

[0043] In addition, in the ultrasonic anemometer 100, a recess 17 is formed at the bottom of the upper body 10, outside the ultrasonic transmitter / receiver 30 with respect to the center line CL1 of the upper body 10, between the hollow portion 50 and the ultrasonic transmitter / receiver 30 in the X-axis direction.

[0044] According to the ultrasonic anemometer 100 having this configuration, the recesses 17 are formed on the outside of the multiple ultrasonic transmitters and receivers 30, which prevents the flow path 101 from adhering to the bottom surface 30b of the ultrasonic transmitters and receivers 30 along the bottom surface of the upper body 10. A downwardly protruding convex portion is formed between the ultrasonic transmitters and receivers 30 and the recess 17, which prevents raindrops 110 from adhering to the bottom surface 30b of the ultrasonic transmitters and receivers 30. Here, the presence of the recesses 17 in addition to the hollow portion 50 provides a double protection against raindrops 110 adhering.

[0045] In addition, in the ultrasonic anemometer 100, the inclination angle θ1 of the inclined surface 41 (the outer surface of the inclined portion) of the umbrella portion 40 with respect to the X-axis direction is set so that the kinetic energy of the raindrop 110 falling on the inclined surface 41 is greater than the surface tension of the raindrop 110 adhering to the inclined surface 41. In other words, if the surface tension is large, the raindrop will not fall from the tip 40a of the umbrella portion 40 but will remain on the bottom surface of the umbrella portion 40. As a result, the raindrop may travel along the bottom surface of the umbrella portion 40 and reach the surface of the ultrasonic transceiver 30. For example, the surface tension energy of a raindrop at room temperature is assumed to be 0.008 mJ. It is sufficient that the kinetic energy at the tip 40a of the umbrella portion 40 exceeds the surface tension energy of 0.008 mJ. If the length of the inclined surface is approximately 10 mm, the inclination angle θ1 must be, for example, 65 degrees or greater, so that the kinetic energy exceeds the surface tension energy.

[0046] According to the ultrasonic anemometer 100 having this configuration, raindrops 110 falling along the inclined surface 41 separate from the inclined surface 41 at the tip 40a. The tip 40a of the umbrella portion 40 is positioned radially outward of the lower body 20, so that the raindrops 110 falling from the tip 40a are prevented from adhering to the surface of the lower body 20.

[0047] [Ultrasonic anemometer 100B according to a second embodiment] Next, an ultrasonic anemometer 100B according to a second embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100B according to the second embodiment. The ultrasonic anemometer 100B according to the second embodiment shown in Fig. 5 differs from the ultrasonic anemometer 100 shown in Fig. 3 in that the umbrella portion 40 is detachable from the main body 15. Note that in the description of the second embodiment, descriptions that are the same as those of the first embodiment may be omitted.

[0048] The upper body 10 of the ultrasonic anemometer 100B according to the second embodiment includes an umbrella portion 40. The umbrella portion 40 has an inclined portion 45, a top plate 46, and a connecting portion 47. The top plate 46 is disk-shaped and is disposed so as to cover the main body 15 from above. The top plate 46 may simply be placed on the main body 15, or may be fixed to the main body 15. The top plate 46 is attachable to and detachable from the main body 15.

[0049] The connecting portion 47 is, for example, cylindrical and is formed so as to hang down from the outer periphery of the top plate 46. The connecting portion 47 connects the top plate 46 and the inclined portion 45 in the Z-axis direction. The upper end of the connecting portion 47 is connected to the top plate 46, and the lower end of the connecting portion 47 is connected to the upper end of the inclined portion 45. The top plate 46, the connecting portion 47, and the inclined portion 45 are formed as a single unit. For example, the umbrella portion 40 can be attached to the main body 15 by placing the umbrella portion 40 over the main body 15 from above.

[0050] The umbrella portion 40 may be configured to be engaged with the upper portion of the main body 15, or may be configured to be engaged with the side portion of the main body 15. For example, a flange portion that protrudes radially outward may be formed on the side portion of the main body 15. The umbrella portion 40 may be configured to be attached to a flange portion that protrudes from the main body 15. When the umbrella portion 40 is configured to cover the entire main body 15, it is easy to prevent raindrops 110 from entering the flow path 101.

[0051] The ultrasonic anemometer 100B according to the second embodiment also provides the same effects as the ultrasonic anemometer 100 according to the first embodiment.

[0052] In the ultrasonic anemometer 100B according to the second embodiment, the upper body 10 includes a main body (first portion) 15 on which the ultrasonic transceiver 30 is mounted, and an umbrella portion (second portion) that is disposed outside the main body 15 in the X-axis direction and has an inclined portion 45. The umbrella portion 40 is detachable from the main body 15. In this ultrasonic anemometer 100B, for example, the umbrella portion 40 can be attached to an ultrasonic anemometer of a type that does not have an existing umbrella portion 40.

[0053] [Positional Relationship Between the Tip 40a of the Umbrella Part 40 and the End 20a on the Top Surface of the Lower Body 20] Next, a description will be given of the positional relationship between the tip 40a of the umbrella part 40 and the end 20a on the top surface of the lower body 20. The positional relationship between the tip 40a of the umbrella part 40 and the end 20a on the top surface of the lower body 20 is applicable to the ultrasonic anemometers 100 and 100B according to the first and second embodiments.

[0054] The first angle θ11 between the imaginary first line L12 extending in the Z-axis direction from the tip 40a of the umbrella portion 40 and the imaginary second line L11 connecting the tip 40a of the umbrella portion 40 and the end 20a of the upper surface of the lower body 20 is an angle set so that the raindrops 110 falling from the tip 40a of the umbrella portion 40 do not reach the upper surface of the lower body 20 at the maximum wind speed when the raindrops 110 attached to the lower surface of the upper body 10 are not blown away by the wind. Here, when the raindrops 110 reach the upper surface of the lower body 20, there is a possibility that the raindrops 110 will be reflected by the upper surface of the lower body 20 and stick to the surface of the ultrasonic transceiver 30. To prevent this problem, the shape of the umbrella portion 40 can be set as follows.

[0055] For example, at low wind speeds of wind speed (1) 5 m / sec or less, raindrops 110 attached to the underside of the upper structure 10 may not be blown away by the wind. For example, suppose that raindrops measuring approximately 25% or more of the surface (bottom surface 30b) of the ultrasonic transceiver 30 affect ultrasonic transmission. If the diameter of the ultrasonic transceiver 30 is 11.5 mm, raindrops with a diameter of approximately 3 mm should not adhere to the surface of the ultrasonic transceiver 30. When a raindrop with a diameter of approximately 3 mm falls vertically, the fall speed (2) when the air resistance and the weight of the raindrop are balanced is 8.1 to 7.4 m / sec. In other words, the first angle θ11 should be greater than the angle θ12 calculated by the arctangent of wind speed (1) / fall speed (2). The first angle θ11 should be, for example, 33 degrees or greater.

[0056] In the ultrasonic anemometers 100 and 100B, the tip 40a of the umbrella portion 40 is set relative to the lower body 20 so as to form the first angle θ11 that satisfies the above relationship. For example, if the dimension LA from the tip 40a to the lower body 20 (e.g., the end 20a of the upper surface) in the Z-axis direction is 14 mm, the dimension LB from the tip 40a to the lower body 20 in the X-axis direction (the protection range of the umbrella portion 40) may be set to approximately 9.1 mm or greater.

[0057] The ultrasonic anemometers 100 and 100B configured as described above suppress the adhesion of raindrops 110 to the upper surface of the lower body 20. In the ultrasonic anemometers 100 and 100B, the adhesion of raindrops 110 to the second plane 22 is suppressed. In the ultrasonic anemometers 100 and 100B, the adhesion of raindrops 110 to the upper surface of the lower body 20 is suppressed during strong winds, allowing the ultrasonic anemometers 100 and 100B to accurately measure wind direction and wind speed. Furthermore, by calculating the first angle θ11, the protection range of the umbrella portion 40 can be optimized, preventing the ultrasonic anemometer 100 from becoming too large.

[0058] [Ultrasonic Anemometer 100C According to a Third Embodiment] Next, an ultrasonic anemometer 100C according to a third embodiment will be described with reference to FIGS. 6 to 8. FIG. 6 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100C according to the third embodiment, taken along the X-Z plane. FIG. 7 is a bottom view illustrating the bottom surface of the upper body 10 and the bottom surface of the shielding plate 60 of the ultrasonic anemometer 100C according to the third embodiment. FIG. 8 is a partially enlarged cross-sectional view illustrating the umbrella portion 40, cavity portion 50, and shielding plate 60 of the ultrasonic anemometer 100C according to the third embodiment. The ultrasonic anemometer 100C according to the third embodiment shown in FIG. 6 differs from the ultrasonic anemometer 100 shown in FIG. 3 in that it includes a shielding plate 60 that covers the opening of the cavity portion 50. Note that, in the description of the third embodiment, descriptions similar to those of the first embodiment may be omitted.

[0059] [Shielding Plate 60] As shown in FIGS. 6 to 8 , the ultrasonic anemometer 100 includes a shielding plate 60. The shielding plate 60 is an example of a shielding portion. As shown in FIG. 8 , the shielding plate 60 is arranged to cover the opening of the cavity 50. The opening of the cavity 50 faces downward. As described above, the cavity 50 is formed to be recessed upward. As shown in FIG. 7 , the shielding plate 60 is arranged outward of the multiple ultrasonic transmitters / receivers 30 in the X-axis direction and the Y-axis direction. The shielding plate 60 is formed to be ring-shaped when viewed in the Z-axis direction. The shielding plate 60 may be formed to cover the entire periphery of the opening of the cavity 50. The shielding plate 60 may be formed to cover the entire surface of the opening of the cavity 50.

[0060] 6 and 8 , the shielding plate 60 has an upper surface 60a and a lower surface 60b that face each other in the plate thickness direction. The lower surface 60b is located above the first plane 12 of the main body 15. The lower surface 60b is located farther away from the lower body 20 in the Z-axis direction than the first plane 12. The first plane is an example of a lower surface at the center of the upper body.

[0061] The lower surface 60b of the shielding plate 60 is disposed higher than the bottom portion 42 of the umbrella portion 40. The lower surface 60b of the shielding plate 60 is disposed higher than the radially inner end portion 42a of the bottom portion 42.

[0062] The shielding plate 60 is fixed to the umbrella portion 40 by, for example, a plurality of screws 62. The shielding plate 60 has through holes formed therein that penetrate the plate thickness direction. The screws 62 are inserted into the through holes of the shielding plate 60, and heads 62a of the screws 62 are positioned below the lower surface 60b of the shielding plate 60. The umbrella portion 40 has fixing portions 61 to which the screws 62 are fixed. The fixing portion 61 has, for example, a cylindrical shape. A threaded portion is formed on the inner surface of the cylindrical shape. The fixing portion 61 extends downward from, for example, the protruding piece 44. The upper surface 60a of the shielding plate 60 abuts against the lower end of the fixing portion 61. The heads 62a of the screws 62 are positioned above the first plane 12 and the tip portion 40a of the umbrella portion 40. In other words, the heads 62a of the screws 62 do not protrude downward below the first plane 12 and the tip portion 440a. For example, in a method for manufacturing the ultrasonic anemometer 100, the shielding plate 60 can be fixed to the fixing part 61 by attaching a screw 62 while the shielding plate 60 is pressed against the lower end of the fixing part 61. Furthermore, the head 62a of the screw 62 may be positioned so as not to protrude from the lower surface 60b of the shielding plate 60.

[0063] 7, the shielding plate 60 is disposed so as to cover the entire opening of the cavity 50 when viewed from below in the Z-axis direction. The shielding plate 60 is not limited to one that covers the entire opening of the cavity 50.

[0064] [Reflection of Ultrasonic Wave UT2 on the Inner Surface 43 of the Umbrella Section 40] Next, with reference to FIG. 9 , reflection of ultrasonic waves UT2 on the inner surface 43 of the umbrella section 40 when the shielding plate 60 is not present will be described. FIG. 9 is a schematic cross-sectional view illustrating an ultrasonic anemometer 100 according to a comparative example, showing a cross section along the X-Z plane. For ease of explanation, ultrasonic waves are shown using straight lines, but ultrasonic waves have directionality and are transmitted so as to spread uniformly from the bottom surface 30b of the ultrasonic transceiver 30. Here, ultrasonic waves UT1, whose first reflection occurs on the second plane 22, are ultrasonic waves necessary for measuring the fluid to be measured. On the other hand, ultrasonic waves UT2, whose first reflection occurs on the third plane 23, are ultrasonic waves unnecessary for measuring the fluid to be measured. In other words, ultrasonic waves UT2 are ultrasonic waves that become noise. For example, ultrasonic waves UT2 (UT2-1) transmitted from the ultrasonic transceiver 31 are reflected on the third plane 23 and travel toward the inner surface 43 of the umbrella section 40. If the shielding plate 60 is not disposed so as to cover the cavity 50, the ultrasonic wave UT2-1 hits the inner surface 43 of the umbrella portion 40, is reflected, and travels toward the second plane 22. The ultrasonic wave UT2 (UT2-2) reflected by the second plane 22 may be received by the ultrasonic transceiver 32.

[0065] In this way, the ultrasonic waves UT2 transmitted from the ultrasonic transmitter / receiver 31 may be reflected by the third surface 23 of the lower body 20, the inner surface 43 of the umbrella portion 40, and the second flat surface 22 of the lower body 20, and may be received by the ultrasonic transmitter / receiver 32. Such ultrasonic waves UT2 become acoustic noise when measuring the flow velocity and wind direction of air flowing through the flow path 101. If no measures are taken to deal with such acoustic noise, measurement errors will occur in the ultrasonic anemometer 100.

[0066] [Reflection of Ultrasonic Wave UT3 at Shielding Plate 60] Next, with reference to FIG. 6 , reflection of ultrasonic waves UT3 at the shielding plate 60 will be described. For example, ultrasonic waves UT3 transmitted from the ultrasonic transceiver 31 are reflected by the third surface 23 and travel toward the shielding plate 60. When the shielding plate 60 is positioned to cover the cavity 50, the ultrasonic waves UT3 are reflected off the lower surface 60b of the shielding plate 60 and travel diagonally downward toward the outside of the third surface 23. In this case, the ultrasonic waves UT3 are not received by the ultrasonic transceiver 32 and do not become acoustic noise. However, particularly when the third surface 23 is inclined outward, ultrasonic waves reflected off the third surface 23 are more likely to enter the cavity 50 and are reflected off the inner surface 43. Therefore, providing the shielding plate 60 reduces the ultrasonic waves entering the cavity 50, thereby reducing measurement errors. Even if the third surface 23 is not formed and the entire upper surface of the reflecting plate 21 is the second flat surface 22, ultrasonic waves may still be incident on the inner surface 43 that forms the cavity 50. Even in such a case, the measurement error can be reduced by providing the shielding plate 60.

[0067] [Action and effect of ultrasonic anemometer 100C according to the third embodiment] The ultrasonic anemometer 100C according to the third embodiment comprises an upper body 10 on which an ultrasonic transceiver 30 is mounted and in which a hollow portion 50 is formed at a position other than the portion in which the ultrasonic transceiver 30 is located, a lower body 20 arranged a predetermined distance in the Z-axis direction (first direction) from the upper body 10, and a shielding plate (shielding portion) 60 that covers the opening of the hollow portion 50.

[0068] In the ultrasonic anemometer 100C, the provision of the shielding plate 60 allows ultrasonic waves transmitted from the ultrasonic transceiver 30 and reflected by the lower body 20 to strike the shielding plate 60. This prevents the ultrasonic waves from traveling into the cavity 50. This prevents the ultrasonic waves from being reflected by the inner surface 43 that forms the cavity 50, preventing unnecessary ultrasonic waves from being received by the ultrasonic transceiver 30. That is, in the ultrasonic anemometer 100C, the shielding plate 60 provides a measure against acoustic noise. As a result, the ultrasonic anemometer 100C achieves improved measurement accuracy.

[0069] In the ultrasonic anemometer 100C, the provision of the shielding plate 60 increased the maximum amplitude of the received signal by approximately 10%. Specifically, the ultrasonic anemometer 100 according to the comparative example, which did not include the shielding plate 60, had an attenuation rate of 12.1%, while the ultrasonic anemometer 100C, which included the shielding plate 60, had an attenuation rate of 2.4%. The attenuation rate can be expressed by the following formula (1). For example, the attenuation rate of the received signal received 450 μs after the start of transmission of the transmitted signal can be calculated using the following formula (1).

[0070] Attenuation rate = (maximum received amplitude - received amplitude) / maximum amplitude (1)

[0071] In the ultrasonic anemometer 100C, the hollow portion 50 is positioned outside the ultrasonic transmitter / receiver 30 in the X-axis direction (second direction), and a third surface 23, which is an inclined portion that slopes outward in the X-axis direction and away from the upper body 10 in the Z-axis direction, is formed on the outer periphery of the lower body 20.

[0072] In the ultrasonic anemometer 100C having this configuration, the third surface 23 is formed on the outer periphery of the lower body 20, allowing ultrasonic waves reflected by the third surface 23 to travel outside. In the ultrasonic anemometer 100, ultrasonic waves that would become acoustic noise can be traveled outside so that they are not received by the receiving ultrasonic transceiver 30. On the other hand, if the shielding plate 60 is not provided, the ultrasonic waves UT2-2 reflected by the third surface 23 become noise and interfere with the ultrasonic waves UT1 necessary for wind speed measurement, canceling out the ultrasonic waves UT1.

[0073] In the ultrasonic anemometer 100C, a plurality of ultrasonic transmitters / receivers 30 are mounted on the upper body 10 and spaced apart in the X-axis direction (second direction). The upper surface of the lower body 20 includes a second plane 22 that intersects with the Z-axis direction, and a third surface 23 of the lower body 20 is disposed outside the second plane 22 in the X-axis direction, with a portion of the third surface 23 of the lower body 20 disposed directly below the ultrasonic transmitters / receivers 30.

[0074] The ultrasonic waves transmitted from the ultrasonic transceiver 31 reach the ultrasonic transceiver 32 while reflecting between the lower body 20 and the upper body 10. The distance between the lower body 20 and the upper body 10 determines the transmission distance of the ultrasonic waves. By adjusting this transmission distance, the ultrasonic waves transmitted from the ultrasonic transceiver 31 can reach the ultrasonic transceiver 32 at their strongest. To adjust this transmission distance, it is preferable to reduce the number of times the ultrasonic waves reflect between the lower body 20 and the upper body 10. The number of reflections is preferably three or less. With the ultrasonic anemometer 100C configured as described above, a portion of the ultrasonic waves transmitted from the ultrasonic transceiver 30 is reflected by the third surface 23 located directly below the ultrasonic transceiver 30 and travels outside the ultrasonic anemometer 100C. This limits the number of times the ultrasonic waves transmitted from the ultrasonic transceiver 30 reflect between the lower body 20 and the upper body 10. In the ultrasonic anemometer 100C, the ultrasonic waves received by the ultrasonic transmitter / receiver 32 can be optimized.

[0075] In the ultrasonic anemometer 100C, the upper body 10 includes a main body 15 on which the ultrasonic transceiver 30 is mounted, and an inclined portion 45 located outside the main body 15 in the X-axis direction. A cavity 50 is formed between the inclined portion 45 of the upper body 10 and the main body 15 in the X-axis direction. The inner surface 43 of the inclined portion 45 of the upper body 10 includes an inclined surface whose upper end is located more inward than the lower end. The lower end of the inner surface 43 is located more outward in the radial direction of the main body 15 than the upper end of the inner surface 43.

[0076] According to the ultrasonic anemometer 100C, the umbrella portion 40 including the inclined portion 45 is provided on the upper body 10, thereby preventing raindrops 110 from entering the flow path 101. Furthermore, adhesion of the raindrops 110 to the bottom surface 30b of the ultrasonic transceiver 30 is also prevented. As a result, the ultrasonic anemometer 100C reduces the influence of the raindrops 110 on the measurement results obtained by the ultrasonic transceiver 30. The ultrasonic anemometer 100 reduces the influence of the raindrops 110 during rainy weather, thereby improving the accuracy of measuring wind speed and wind direction. Furthermore, in the ultrasonic anemometer 100C, the structure includes the umbrella portion 40, and the shielding plate 60 is disposed to cover the cavity 50 from below, thereby preventing ultrasonic waves from traveling into the cavity 50 and reducing ultrasonic waves that strike the inner surface 43.

[0077] Furthermore, if the width of the bottom of the umbrella portion 40 (the width along the X-axis direction from the straight line L15 to the tip 40a of the inclined portion 45) is greater than the thickness t15 of the portion constituting the bottom of the main body 15, it is preferable to manufacture the umbrella portion 40 by injection molding rather than casting in order to improve the processing accuracy of the umbrella portion 40. In the case of injection molding, the thickness of each portion of the upper body 10 must be approximately the same, resulting in the formation of a hollow portion 50. Here, if the upper body 10 is manufactured by injection molding, the thickness of the inclined portion 41 of the upper body 10 will be thinner than the width of the lowest part of the hollow portion 50. In other words, the thickness of the inclined portion 41 of the upper body 10 will be thinner than the width W60 of the shielding plate 60 in the X-axis direction.

[0078] However, in the ultrasonic anemometer 100C, the shielding plate 60 prevents ultrasonic waves from traveling into the cavity 50, thereby providing a measure against acoustic noise. According to this embodiment, it is possible to provide the ultrasonic anemometer 100C that has been provided with a measure against acoustic noise.

[0079] In the ultrasonic anemometer 100C, the inner surface 43 of the inclined portion 45 of the upper body 10 is disposed further outward in the X-axis direction than the third surface 23 of the lower body 20. The "outward" side is the side farther from the center line CL1 of the upper body 10 in the radial direction of the main body 15.

[0080] With the ultrasonic anemometer 100C configured as described above, the inclined portion 45 extends outward in the X-axis direction beyond the third surface 23 of the lower body 20, thereby preventing raindrops 110 from entering the flow path 101. With this ultrasonic anemometer 100, adhesion of raindrops 110 to the first flat surface 12, the second flat surface 22, and the bottom surface 30b of the ultrasonic transceiver 30 can be prevented, and a decrease in the accuracy of measuring wind speed and wind direction can be prevented.

[0081] In the ultrasonic anemometer 100C, the lower surface 60b of the shielding plate 60 is positioned farther away from the lower body 20 in the Z-axis direction than the first plane (the lower surface at the center) 12 of the upper body 10. In other words, the lower surface 60b of the shielding plate 60 is positioned above the first plane 12. The lower surface 60b of the shielding plate 60 is not positioned below the first plane 12.

[0082] With the ultrasonic anemometer 100C having this configuration, the shielding plate 60 can be placed in a position that does not interfere with the flow of air flowing between the first plane 12 and the second plane 22. As a result, the generation of turbulence by the shielding plate 60 is prevented, and the wind speed can be measured with high accuracy.

[0083] In the ultrasonic anemometer 100C, the shielding plate 60 is fixed to the upper body 10 by a screw (fixing member) 62, and the head (lower surface) 62a of the screw 62 is located above the lower surface of the upper body 10. The fixing member is not limited to the screw 62, and may be any other rod-shaped fixing member. The lower surface of the upper body 10 may be the first flat surface 12 or the tip portion 40a of the inclined portion 45.

[0084] In the ultrasonic anemometer 100C having this configuration, the head 62a of the screw 62 can be positioned so as not to interfere with the flow of air flowing between the first plane 12 and the second plane 22. As a result, turbulence caused by the screw 62 is prevented, enabling accurate measurement of wind speed. Furthermore, in the ultrasonic anemometer 100, the shielding plate 60 can be fixed to the upper body 10 by tightening the screw 62 from below.

[0085] In the ultrasonic anemometer 100C, the inclined portion 45 of the upper body 10 is plate-shaped and is formed to surround the main body 15. The upper body 10 includes an umbrella portion 40 including the inclined portion 45. The plate thickness direction of the inclined portion 45 of the umbrella portion 40 is inclined with respect to the Z-axis direction, and the bottom portion (lower surface) 42 of the inclined portion 45 of the umbrella portion 40 includes an inclined surface inclined with respect to the XY plane (horizontal plane). The inner end portion 42a of the bottom portion 42 of the inclined portion 45 of the umbrella portion 40 is positioned higher than the outer tip portion 40a of the bottom portion 42. The lower surface 60b of the shielding plate 60 is positioned higher than the bottom portion 42 of the inclined portion 45 of the umbrella portion 40.

[0086] In the ultrasonic anemometer 100C having this configuration, the bottom 42 of the umbrella portion 40 is configured as an inclined surface that can function as a drainage surface. By positioning the inner end 42a of the inclined surface of the bottom 42 at a position higher than the outer tip 40a, raindrops that move downward along the outer inclined surface 41 of the umbrella portion 40 are prevented from moving along the bottom 42 into the inside of the umbrella portion 40. In the ultrasonic anemometer 100, the underside 60b of the shielding plate 60 is positioned higher than the inner end 42a of the bottom 42 of the umbrella portion 40, thereby preventing raindrops from entering the inside of the umbrella portion 40 and reducing acoustic noise.

[0087] In the ultrasonic anemometer 100, the shielding plate 60 is plate-shaped, and the thickness direction of the shielding plate 60 is along the Z-axis direction. In other words, the lower surface 60b of the shielding plate 60 is disposed so as to be along the XY plane.

[0088] In the ultrasonic anemometer 100C having this configuration, the first plane 12, the second plane 22, and the lower surface 60b of the shielding plate 60 are arranged parallel to each other, thereby positioning the shielding plate 60 so as not to interfere with the flow of air between the first plane 12 and the second plane 22, thereby reducing acoustic noise. Furthermore, if the shielding plate 60 is not parallel to the first plane 12 and the second plane 22, ultrasonic waves reflected by the shielding plate 60 may travel inside the ultrasonic anemometer 100C. As a result, the acoustic noise reduction effect may be reduced. Therefore, it is preferable to arrange the first plane 12, the second plane 22, and the lower surface 60b of the shielding plate 60 parallel to each other. Furthermore, to prevent ultrasonic waves from entering the cavity 50, it is preferable to position the shielding plate 60 near the bottom of the cavity 50. It is preferable that the lower surface 60b of the shielding plate 60 be approximately flush with the bottom 42 of the inclined portion 45 of the umbrella portion 40.

[0089] [Ultrasonic anemometer 100D according to Modification 1] Next, an ultrasonic anemometer 100D according to Modification 1 will be described with reference to Fig. 10. Fig. 10 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100D according to Modification 1. The ultrasonic anemometer 100D according to Modification 1 shown in Fig. 10 differs from the ultrasonic anemometer 100C according to the third embodiment shown in Fig. 8 in that it includes a shielding plate 60B instead of the shielding plate 60. The shielding plate 60 is formed so as to cover the entire opening of the cavity 50, but the shielding plate 60B does not cover the entire opening of the cavity 50. Note that in the description of Modification 1, descriptions that are the same as those in the above-described embodiment may be omitted.

[0090] The shielding plate 60B is formed in an annular shape when viewed in the plate thickness direction. A gap is formed between the shielding plate 60B and the side surface 15a of the main body 15 in the X-axis direction. The shielding plate 60B and the inner surface 43 of the inclined portion 45 are in contact with each other in the X-axis direction. The gap between the shielding plate 60B and the main body 15 is continuous around the entire circumference of the main body 15. The shielding plate 60B and the side surface 15a of the main body 15 may be in partial contact with each other in the circumferential direction of the main body 15.

[0091] The ultrasonic anemometer 100D according to Modification 1 has the same advantages as the ultrasonic anemometer 100C. The shielding plate 60B does not need to cover the entire opening of the cavity 50.

[0092] [Ultrasonic anemometer 100E according to Modification 2] Next, an ultrasonic anemometer 100E according to Modification 2 will be described with reference to FIG. 11 . FIG. 11 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100E according to Modification 2. The ultrasonic anemometer 100E according to Modification 2 shown in FIG. 11 differs from the ultrasonic anemometer 100C according to the third embodiment shown in FIG. 8 in that a shielding plate 60C is provided instead of the shielding plate 60. The shielding plate 60C covers most of the opening of the cavity 50, but does not cover the entire opening. Note that in the description of Modification 2, descriptions that are the same as those for the third embodiment and Modification 1 may be omitted.

[0093] The shielding plate 60C is formed in an annular shape when viewed in the plate thickness direction. A gap is formed between the shielding plate 60C and the inner surface 43 of the inclined portion 45 in the X-axis direction. The shielding plate 60C and the side surface 15a of the main body 15 are in contact in the X-axis direction. The gap between the shielding plate 60C and the inner surface 43 of the inclined portion 45 is continuous around the entire circumference of the umbrella portion 40. The shielding plate 60C and the inner surface 43 of the inclined portion 45 may be in partial contact in the circumferential direction of the umbrella portion 40.

[0094] The ultrasonic anemometer 100E according to Modification 2 has the same advantages as the ultrasonic anemometer 100C. The shielding plate 60C does not have to cover the entire opening of the cavity 50.

[0095] [Ultrasonic anemometer 100F according to Modification 3] Next, an ultrasonic anemometer 100F according to Modification 3 will be described with reference to FIG. 12 . FIG. 12 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100F according to Modification 3. The ultrasonic anemometer 100F according to Modification 3 shown in FIG. 12 differs from the ultrasonic anemometer 100C according to the third embodiment shown in FIG. 8 in that a shielding plate 60D is provided instead of the shielding plate 60. The shielding plate 60D covers most of the opening of the cavity 50, but does not cover the entire opening. Note that in the description of Modification 3, descriptions similar to those of the third embodiment, Modifications 1, and 2 may be omitted.

[0096] The shielding plate 60D is formed in an annular shape when viewed in the plate thickness direction. A through hole penetrating the shielding plate 60D in the plate thickness direction is formed in the shielding plate 60D. This through hole may be formed in the center in the width direction of the shielding plate 60D. The width direction of the shielding plate 60D may be the X-axis direction in FIG. 12. The through hole is formed partially in the circumferential direction of the shielding plate 60D. The shielding plate 60D may be in contact with the side surface of the main body 15. The shielding plate 60D may be in contact with the inner surface 43 of the inclined portion 45.

[0097] The ultrasonic anemometer 100F according to Modification 3 has the same advantages as the ultrasonic anemometer 100C. The shielding plate 60D does not have to cover the entire opening of the cavity 50.

[0098] [Ultrasonic anemometer 100G according to Modification 4] Next, an ultrasonic anemometer 100G according to Modification 4 will be described with reference to Fig. 13. Fig. 13 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100G according to Modification 4. The ultrasonic anemometer 100G according to Modification 4 shown in Fig. 13 differs from the ultrasonic anemometer 100C according to the third embodiment shown in Fig. 8 in that a shielding portion 60E is disposed so as to fill the cavity 50. Note that in the description of Modification 4, descriptions that are the same as those for the third embodiment and Modifications 1 to 3 may be omitted.

[0099] The shielding portion 60E may be formed of, for example, resin. The shielding plate 60E is formed in a circular ring shape when viewed in the Z-axis direction. For example, the shielding plate 60E may be formed by filling the cavity 50 with resin or the like.

[0100] The ultrasonic anemometer 100G according to the fourth modification has the same effects as the ultrasonic anemometer 100C. The shielding portion that covers the opening of the cavity 50 is not limited to a plate shape.

[0101] 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.

[0102] In the above embodiment, the ultrasonic anemometer 100C is illustrated in which the shielding plate 60 is formed to shield the opening of the cavity 50 in the umbrella portion 40, but the cavity is not limited to being formed in the umbrella portion 40. For example, in the ultrasonic anemometer 100, a shielding portion may be formed to shield the opening of the cavity formed in the main body 15.

[0103] BACKGROUND ART

[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. This wind direction and speed measuring device includes a housing having a flow path through which the fluid to be measured flows, and a pair of ultrasonic transmitters and receivers installed at a predetermined inclination relative to the flow path (for example, as described in JP 2014-77643 A).

[0104] [Problem] Conventional techniques have room for improvement in terms of measures against acoustic noise. The present disclosure provides an ultrasonic anemometer that can suppress the effects of acoustic noise on measurement results.

[0105] This international application claims priority based on Japanese Patent Application No. 2024-055914 filed on March 29, 2024, and Japanese Patent Application No. 2024-104197 filed on June 27, 2024. The entire contents of Japanese Patent Application No. 2024-055914 and Japanese Patent Application No. 2024-104197 are incorporated by reference into this international application.

[0106] 100, 100B, 100C, 100D, 100E, 100F: ultrasonic anemometer, 10: upper body, 11: top plate, 12: first plane (underside of center of upper body), 20: lower body, 21: reflector, 22: second plane, 23: third plane (inclined portion of lower body), 30: ultrasonic transmitter / receiver, 31: ultrasonic transmitter / receiver, 32: ultrasonic transmitter / receiver, 40: umbrella portion, 40a: tip portion (outer end of underside of inclined portion), 42: bottom portion (underside of inclined portion) ), 42a: end (inner end of the lower surface of the inclined portion), 43: inner surface (inclined surface), 45: inclined portion (inclined portion of the upper body), 50: hollow portion, 60, 60B, 60C, 60D: shielding plate (shielding portion), 60a: upper surface (upper surface of the shielding portion), 60b: lower surface (lower surface of the shielding portion), 62: screw (fixing member), 62a: head, CL1: center line (center of the upper body), X: X-axis direction (second direction), Y: Y-axis direction (third direction), Z: Z-axis direction (first direction).

Claims

1. An ultrasonic anemometer comprising: an upper body on which an ultrasonic transmitter / receiver is mounted; and a lower body arranged at a predetermined distance in a first direction from the upper body, wherein the outer edge of the upper body is formed with an inclined portion that extends in a second direction that intersects with the first direction when viewed in the first direction.

2. The ultrasonic anemometer according to claim 1, wherein a cavity is formed between said inclined portion and said ultrasonic transmitter / receiver in said second direction.

3. An ultrasonic anemometer as described in claim 1 or 2, wherein the bottom surface of the upper body includes a first plane that is aligned with the second direction and a third direction that intersects with the second direction, and the bottom of the inclined portion is inclined so that the part farther from the center of the upper body in the second direction is positioned closer to the lower body in the first direction than the part closer to the center of the upper body in the second direction.

4. An ultrasonic anemometer as claimed in any one of claims 1 to 3, wherein the bottom of the upper body has a corner located inward of the inclined portion in the second direction, a cavity is formed between the corner and the inclined portion in the second direction, and the corner formed on the bottom of the upper body is rounded.

5. An ultrasonic anemometer as described in claim 2 or 4, wherein a recess is formed at the bottom of the upper body, outside the ultrasonic transmitter / receiver relative to the center of the upper body, and between the hollow portion and the ultrasonic transmitter / receiver in the second direction.

6. An ultrasonic anemometer as claimed in any one of claims 1 to 5, wherein the inclination angle of the outer surface of the inclined portion with respect to the second direction is set so that the kinetic energy of raindrops falling on the inclined portion is greater than the surface tension energy of raindrops adhering to the outer surface of the inclined portion.

7. An ultrasonic anemometer according to any one of claims 1 to 6, wherein the upper body comprises: a first part on which the ultrasonic transmitter / receiver is mounted; and a second part which is arranged outside the first part in the second direction and has the inclined part; and the second part is detachable from the first part.

8. An ultrasonic anemometer as claimed in any one of claims 1 to 7, wherein a first angle between an imaginary first line extending from the tip of the inclined portion in the first direction and an imaginary second line connecting the tip of the inclined portion and the end of the upper surface of the lower body is set so that raindrops falling from the tip of the inclined portion do not reach the upper surface of the lower body at a maximum wind speed when raindrops adhering to the lower surface of the upper body are not blown away by the wind.

9. The ultrasonic anemometer according to claim 8, wherein the first angle is 33 degrees or greater.

10. The ultrasonic anemometer according to any one of claims 2 to 9, further comprising a shielding section that covers the opening of the cavity formed in the upper body.

11. An ultrasonic anemometer comprising: an upper body on which an ultrasonic transmitter / receiver is mounted and in which a hollow portion is formed at a position other than where the ultrasonic transmitter / receiver is located; a lower body positioned a predetermined distance from the upper body in a first direction; and a shielding portion that covers the opening of the hollow portion.

12. An ultrasonic anemometer as described in claim 11, wherein the hollow portion is positioned outside the ultrasonic transmitter / receiver in a second direction intersecting the first direction, and the outer periphery of the lower body is formed with an inclined portion that inclines so as to move away from the upper body in the first direction as it moves outward in the second direction.

13. An ultrasonic anemometer as described in claim 12, wherein the upper body is equipped with a plurality of ultrasonic transmitters / receivers spaced apart in a second direction intersecting the first direction, the upper surface of the lower body includes a plane intersecting the first direction, the inclined portion of the lower body is arranged outside the plane in the second direction, and a portion of the inclined portion of the lower body is arranged directly below the ultrasonic transmitters / receivers.

14. An ultrasonic anemometer as claimed in any one of claims 11 to 13, wherein the upper body comprises a main body on which the ultrasonic transmitter / receiver is mounted and an inclined portion arranged on the outside of the main body in a second direction intersecting the first direction, the cavity portion being formed between the inclined portion of the upper body and the main body in the second direction, and the inner surface of the inclined portion of the upper body includes an inclined surface whose upper end is arranged more inward than its lower end.

15. The ultrasonic anemometer according to claim 14, wherein the inclined portion of the upper body is positioned further outward in the second direction than the inclined portion of the lower body.

16. An ultrasonic anemometer according to any one of claims 11 to 15, wherein the upper surface of the lower body includes a plane that intersects with the first direction, and the lower surface of the shielding part is parallel to the plane.

17. An ultrasonic anemometer as claimed in any one of claims 11 to 16, wherein in the first direction, the underside of the shielding portion is positioned farther from the lower body than the underside of the central part of the upper body.

18. An ultrasonic anemometer according to claim 17, wherein the shielding portion is fixed to the upper body by a fixing member, and the lower surface of the fixing member is positioned higher than the lower surface of the upper body in the first direction.

19. An ultrasonic anemometer as described in claim 14, wherein the inclined portion of the upper body is plate-shaped and formed to surround the main body, the thickness direction of the inclined portion of the upper body is inclined relative to the first direction, the lower surface of the inclined portion of the upper body includes an inclined surface inclined relative to a horizontal plane, the inner end of the lower surface of the inclined portion of the upper body is positioned higher than the outer end of the lower surface, and the lower surface of the shielding portion is positioned higher than the lower surface of the inclined portion of the upper body.

20. An ultrasonic anemometer as described in claim 1, wherein the thickness of the inclined portion of the upper body is thinner than the width of the shielding portion in a second direction intersecting the first direction.

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