Water Level Sensor

Abstract

To provide a water level sensor which can easily check when bonding a casing and a horn with an adhesive while ensuring sufficient bonding strength.SOLUTION: A water level sensor includes a wave transmitting / receiving unit 11 that transmits and receives ultrasonic waves, a housing 20 having an opening R, in which the wave transmitting / receiving unit 11 is housed and through which ultrasonic waves pass, formed in a lower surface part 21, and a horn 30 installed near the opening R of the housing 20. The horn 30 includes a horn body 31 having an upper part of a small diameter and a lower part of a large diameter, and an upper part inserted into the opening R, an annular outer wall portion 34 extending upward from the horn body 31, and an annular space portion 35 formed between the horn body 31 and the outer wall portion 34. In the horn 30 installed near the opening R, a gap S1 formed by the lower surface part 21 and the space portion 35 is filled with adhesive T. The outer wall portion 34 has a groove part 37 communicating with the outside from the space portion 35 side at an upper end 34a thereof, and has a through hole 36 communicating with the outside from the space portion 35 side in the lower part of the outer wall portion 34.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water level sensor that measures the water level using ultrasonic waves. [Background technology]

[0002] Conventionally, surveying devices have been used to observe changes in river water levels and flooding of roads. The devices mainly consist of a sensor that actually measures the water level and a communication unit that transmits the measured data to administrators, etc. The sensors can be classified into direct methods that directly sense the water level and indirect methods that indirectly measure the water level.

[0003] In the case of the direct method, a water pressure sensor is often used, with the tip of the sensor located at the normal water level. The sensor is installed in a location where it will not be submerged even if the water level rises, so the device itself tends to be large-scale. In addition, in order to measure the water level, it is necessary to set the origin position at the installation site, which makes installation difficult for engineers without specialized knowledge.

[0004] In the case of the indirect method, for example, an ultrasonic sensor is used that transmits ultrasonic waves from an ultrasonic transmitter and calculates the distance from the time it takes for the reflected waves to be received from an object, such as the surface of water or the ground.

[0005] In the case of the indirect method described above, a sensor including an ultrasonic transmitter and a communication unit are housed within a housing, and an opening is formed at the location where the ultrasonic waves are transmitted, generally on the underside of the housing, through which the ultrasonic waves pass from the ultrasonic transmitter to the target object, and a horn is attached to the outer periphery of the through-hole to more efficiently transmit and receive the ultrasonic waves.

[0006] The present applicant discloses in Cited Document 1 an ultrasonic sensor comprising a transmitter / receiver that transmits ultrasonic waves in a predetermined direction and receives reflected waves of the transmitted ultrasonic waves, a housing that houses the transmitter / receiver and has at least one opening, a horn attached to the opening of the housing, and a breathable sheet that covers the opening at the bottom of the horn. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Application No. 2021-189128 Summary of the Invention [Problem to be solved by the invention]

[0008] In the ultrasonic sensor disclosed in Patent Document 1, the housing and the horn attached to its opening may be made of metal such as steel or aluminum alloy, or synthetic resin, but the housing and horn are usually formed separately and bonded together using an adhesive. This is because separate bodies allow for a wider range of material choices for the housing and horn, and fastening devices such as bolts and screws near the ultrasonic transmitter may cause distortion in the housing, which could cause deviation of the ultrasonic wave emission axis. On the other hand, when bonding the housing and horn together with an adhesive, it is necessary to ensure sufficient bonding strength while preventing the adhesive from blocking the opening through which the ultrasonic waves pass.

[0009] The present invention solves the above-mentioned problems and provides a water level sensor that ensures sufficient bonding strength when bonding the housing and horn with an adhesive, while making it easy to check the bonding strength. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention is configured as follows: A water level sensor according to the present invention comprises: a wave transmitting / receiving unit that transmits ultrasonic waves in a predetermined direction and receives reflected waves of the transmitted ultrasonic waves; a housing that houses the wave transmitting / receiving unit and has an opening in its underside through which the ultrasonic waves pass; and a horn attached to the housing near the opening with an adhesive, the horn comprising a horn body having a small diameter at an upper part and a large diameter at a lower part, the upper part of which is inserted into the opening; an annular outer wall portion that extends upward from a vertically middle part of the horn body; and an annular space formed between the horn body and the outer wall portion, the gap formed by the lower surface and the space in the horn attached near the opening being filled with the adhesive, and the outer wall portion having a groove at its upper end that leads from the space side to the outside, and a through hole at its lower part that leads from the space side to the outside.

[0011] In the present invention, a gap may be formed between the horn body and the opening into which the horn body is inserted. [Effects of the Invention]

[0012] According to the water level sensor of the present invention, it is possible to check through the groove and through hole whether the amount of adhesive filled near the opening for adhering the horn is sufficient, making it easy to check the adhesive filling status and preventing poor adhesion. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a front view showing an embodiment of a water level sensor according to the present invention; [Figure 2] 1 is a schematic diagram of a sensor body of a water level sensor according to the present invention. [Figure 3] FIG. 2 is an enlarged front view of the vicinity of the water level sensor in FIG. [Figure 4] FIG. 4 is a side view of FIG. 3. [Figure 5] FIG. [Figure 6]4A and 4B are explanatory diagrams of a mounting structure of a horn to a housing. [Figure 7] FIG. 7 is an enlarged view of the vicinity of the through-hole of the horn in FIG. 6(a). [Figure 8] FIG. 7 is an enlarged view of the vicinity of the groove of the horn in FIG. 6(a). [Figure 9] 5 is an enlarged bottom view of the vicinity of the opening of the housing in FIG. 4. FIG. [Figure 10] FIG. 5 is an enlarged top view of the horn of FIG. 4. [Figure 11] 10A to 10C are explanatory diagrams showing an example of a procedure for attaching the horn to the housing. [Figure 12] 10A to 10C are explanatory diagrams showing an example of a procedure for attaching the horn to the housing. [Figure 13] FIG. 2 is an enlarged view of the vicinity of the fixing member in FIG. [Figure 14] FIG. 14 is an enlarged cross-sectional view taken along the line BB in FIG. [Figure 15] FIG. 14 is an enlarged cross-sectional view taken along the line CC in FIG. 13. [Figure 16] FIG. 14 is a view taken along arrow D in FIG. [Figure 17] FIG. 14 is an explanatory diagram of the receiving member of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, the best mode for carrying out the present invention will be specifically described with reference to the drawings.

[0015] In the drawing, 10 is a sensor body equipped with a transmitting and receiving unit 11 that receives and transmits ultrasonic waves to measure the water level, 20 is a housing that contains the sensor body 10 equipped with the transmitting and receiving unit 11, and 30 is a horn that is attached near the opening R formed in the housing 20, and the water level sensor 100 of the present invention is mainly composed of the sensor body 10, the housing 20 and the horn 30.

[0016] FIG. 1 is a front view showing one embodiment of a water level sensor according to the present invention. The water level sensor 100 measures the water level of a river and is fixed so as to be positioned above the water surface. The fixing structure in this embodiment is such that the water level sensor 100 is attached near the tip of a support member 50 that is fixed to a post 40 of a protective fence installed on the river bank and protrudes into the river. In this embodiment, the water level sensors 100 are installed side by side, allowing for alternate measurements or allowing for continuous measurement in the event of a failure of one. Unless otherwise specified, the front side of the water level sensor 100 refers to the front side of FIG. 1, the rear side refers to the back side of FIG. 1, and the left and right directions refer to the left and right directions of FIG. 1, and the following description will be based on this. In this embodiment, the water level sensor 100 is fixed to the post 40 of the protective fence, but the installation location of the water level sensor 100 is not limited thereto. Other examples include roadside equipment such as balustrades, handrails, and signs (pillars). Furthermore, being installed on road incidental facilities includes cases where the equipment is attached to the road incidental facilities via a support material 50 as in this embodiment, and cases where the equipment is attached directly to the road incidental facilities using mounting brackets or the like.

[0017] Fig. 2 is a schematic diagram of the sensor main body 10. As shown in Fig. 1, the sensor main body 10 comprises a wave transmitting / receiving unit 11 that transmits ultrasonic waves toward the water surface of the river and receives the waves reflected by the water surface, a communication unit 12 that communicates information about the ultrasonic waves transmitted and received by the wave transmitting / receiving unit 11, a power supply unit 13 that supplies power, and a control unit 14 that controls the operation of the sensor main body 10, and these are housed in a housing 20.

[0018] The wave transmitting / receiving unit 11 transmits ultrasonic waves generated from a built-in ultrasonic element in a predetermined direction, and receives the reflected waves that are reflected by the object to be measured. In this embodiment, the predetermined direction is the direction toward the water surface of the river, which is approximately vertically downward.

[0019] The communication unit 12 transmits wave transmission information and wave reception information to the administrator. The wave transmission information includes at least the time of transmission and the intensity of the ultrasonic waves at the time of transmission, and the wave reception information includes at least the time of reception of the reflected waves and the intensity of the received ultrasonic waves. In this embodiment, the communication means is an LPWA wireless communication means, which receives information at a receiving base station newly installed in a location close to the installation location or an existing receiving base station close to the installation location, and receives each piece of information at the administrator's receiving terminal via the Internet.

[0020] In this embodiment, a battery is used for the power supply unit 13. This eliminates the need for power supply from outside the housing 20 that houses the sensor main body 10, and allows for continuous power supply regardless of the weather in the installation environment. Although not shown, depending on the installation environment and conditions, instead of placing the power supply unit 13 inside the housing 20, power may be supplied using a power supply device that uses a commercial power source or a solar panel.

[0021] Figure 3 is an enlarged front view of the vicinity of water level sensor 100 in Figure 1, and Figure 4 is a side view of Figure 3. Housing 20 is box-shaped with an open top, and houses sensor main body 10. Underside 21 of housing 20 has opening R, and horn 30 is attached near opening R, and lid 22 is attached and closed above. In this embodiment, housing 20 is rectangular, but is not particularly limited as long as it has a structure that can house sensor main body 10 and does not easily allow rainwater and the like to penetrate inside.

[0022] 5 is an exploded view of the horn. Horn 30 comprises horn body 31, which has a small diameter at the top and a large diameter at the bottom, and whose top is inserted into opening R. Ring-shaped cap 32 fits onto the bottom of horn body 31. Breathable sheet material 33 is placed between horn body 31 and cap 32 to close the opening on the bottom side of horn body 31. This prevents rainwater and creatures such as spiders and insects from entering the interior of horn body 31 from the outside, while allowing ultrasonic waves to pass through.

[0023] 6 to 9 are explanatory diagrams of the mounting structure of the horn 30 to the housing 20, with Fig. 6(a) being an enlarged end view taken along line AA in Fig. 4, and Fig. 6(b) being an exploded explanatory view of Fig. 6(a). Also, Fig. 7 is an enlarged view of the vicinity of the through-hole of the horn in Fig. 6(a), Fig. 8 is an enlarged view of the vicinity of the groove of the horn in Fig. 6(a), Fig. 9 is an enlarged bottom view of the vicinity of the opening of the housing in Fig. 4, and Fig. 10 is an enlarged top view of the horn in Fig. 4. An opening R that penetrates part of the bottom surface 21 of the housing 20 in the vertical direction is formed, and the transmitting / receiving unit 11 is disposed above the opening R. Ultrasonic waves transmitted from the transmitting / receiving unit 11 pass through the horn 30 attached near the opening R, are reflected near the water surface below, pass through the horn 30 again, and are received by the transmitting / receiving unit 11 through the opening R.

[0024] Horn 30 has an outer wall portion 34 that extends upward from the vertical middle portion of horn body 31. As shown in Figures 5 and 9, outer wall portion 34 has a closed annular cross section, and an annular space portion 35 is formed between horn body 31 and outer wall portion 34.

[0025] The lower part of the outer wall part 34 has a through hole 36 that leads from the space part 35 to the outside. The outer wall part 34 also has a groove part 37 with a U-shaped cross section at its upper end 34a that leads from the space part 35 side to the outside.

[0026] The upper end 34a of the outer wall portion 34 is lower than the upper end 31a of the horn body 31. Therefore, when the upper end 31a of the horn body 31 is inserted into the opening R, as shown in Figures 6(a), 7 and 8, the upper end 34a of the outer wall portion 34 abuts against the lower surface 21 of the housing 20, forming a gap corresponding to the annular space 35 between the housing 20 and the horn body 31. However, in this embodiment, as shown in Figures 6 and 10, an annular protrusion 23 is formed on the lower surface 21 extending downward from the peripheral edge of the opening R, so that the protrusion 23 is positioned in part of the gap, and a gap S1 is formed between the horn body 31 and the lower surface 21 of the housing 20, including the protrusion 23.

[0027] 11 and 12 are explanatory diagrams showing an example of the procedure for attaching a horn to a housing. As shown in FIG. 11, adhesive T is poured into space 35 of horn 30. At this time, there is a possibility that adhesive T will leak out from through-hole 36, so it is preferable to use adhesive T with a moderate viscosity. Next, upper end 31a of horn body 31 is inserted into opening R of housing 20. This fills gap S1 between housing 20 and horn 30 shown in FIG. 6 with adhesive T.

[0028] Of the adhesive T filled in the gap S1, excess adhesive T flows out through the through-hole 36 and the groove 37. Then, as shown in Fig. 12, if it is possible to confirm that adhesive T has flowed out from both the upper groove 37 and the lower through-hole 36 in terms of the vertical positional relationship, it can be determined that adhesive T has filled the entire gap S1. The flowed-out adhesive T can be removed using a spatula or the like.

[0029] If no adhesive T is confirmed to be leaking out from at least one of the through hole 36 and the groove portion 37, the amount of adhesive T filled may be insufficient, so the horn 30 can be removed from the housing 20, additional adhesive T can be poured into the space portion 35, and the above-mentioned process can be repeated.

[0030] In this embodiment, the through hole 36 and the groove 37 are disposed on opposite sides of the horn body 31. This makes it easier for the adhesive T to fill the entire gap S1.

[0031] Furthermore, in this embodiment, as shown in Figure 7, when the outer wall portion 34 of the horn body 31 is abutted against the lower surface portion 21 of the housing 20, the horn body 31 inserted into the opening R of the housing 20 is separated from the inner surface of the opening R, forming a gap S2.

[0032] As a result, excess adhesive T filled into gap S1 can flow not only through through-hole 36 and groove 37 but also through gap S2 to the upper end 31a of horn body 31, bonding horn body 31 to the inner surface of opening R, thereby more firmly bonding housing 20 and horn 30.

[0033] Gap S2 may be formed over the entire outer peripheral surface of horn body 31, or may be in a state in which horn body 31 and the inner peripheral surface of opening R are partially in contact with each other. In either case, by filling gap S2 with adhesive T, housing 20 and horn 30 are more firmly bonded together.

[0034] Next, as shown in Figures 3 and 4, the water level sensor unit 200 is an integrated unit in which two water level sensors 100 are attached to a connecting member 60, and is fixed to the support material 50 via the connecting member 60. The connecting member 60 has an L-shaped cross section and includes a bottom plate portion 61 and a side plate portion 62, and the side plate portion 62 is fixed to the support material 50. In addition, the two water level sensors 100 are arranged on the underside of the bottom plate portion 61 and fixed via fasteners. In this embodiment, the fasteners consist of a bolt member 63 that passes through the housing 20 and the bottom plate portion 61 from bottom to top, and a nut member 64 that is fastened to the bolt member 63.

[0035] The head 63a of the bolt member 63 is located below, and the nut member 64 is disposed above the bottom plate portion 61. A disk-shaped washer 65 is disposed between the head 63a and the underside 21 of the housing 20. Meanwhile, as shown in Figures 5 and 9, a fitting recess 38 is formed in the outer periphery of the outer wall portion 34 of the horn body 31, which is cut out to fit a part of the washer 65.

[0036] In this embodiment, the procedure involves attaching two water level sensors 100 to the connecting member 60, and then attaching the horn 30 to the housing 20. By positioning the mating recess 38 in the direction of the washer 65, the orientation of the horn 30, i.e., in this embodiment, since the appearance of the horn body 31 is elliptical in cross section, it can be positioned so that the long axis of the elliptical shape is oriented in a predetermined direction relative to the housing 20.

[0037] Additionally, recesses 34b are formed at predetermined intervals on the inner periphery of outer wall 34 of horn body 31. In this embodiment, three recesses 34b are formed. Meanwhile, protrusion 23 of housing 20 has convex portions 23a formed at positions corresponding to the recesses 34b. As a result, even if fitting recesses 38 are not noticed when attaching horn 30 to housing 20, if the positional relationship between convex portions 23a and recesses 34b is misaligned, the attachment work may not go well, resulting in horn 30 being positioned at an angle relative to housing 20 or an unnecessarily large gap. This makes it easy to notice the malfunction, and horn 30 can be returned to the specified orientation and the attachment work redone.

[0038] Next, an example of a method for installing the water level sensor 100 will be described. In this embodiment, the installation location is a river bank, but other locations such as a river bridge are also envisioned. A support member 50 is attached to a support post 40 of a protective fence or handrail installed on a bank or bridge. One end of the support member 50 in the longitudinal direction is fixed to the support post 40 via a fixing member 70, and the water level sensor unit 200 is attached to the other end.

[0039] Fig. 13 is an enlarged view of the vicinity of the fixing member in Fig. 1, Fig. 14 is an enlarged cross-sectional view taken along line BB in Fig. 13, Fig. 15 is an enlarged cross-sectional view taken along line CC in Fig. 13, and Fig. 16 is a view taken along arrow D in Fig. 13. Fixing member 70 has a pressing member 71 arranged along the outer periphery of support column 40 and a receiving member 80 attached to support material 50, with support column 40 fixed between pressing member 71 and receiving member 80. Pressing member 71 is formed in a hat-shaped cross section, and includes a support column fitting portion 72 with a U-shaped cross section and a fixing portion 73 with through-holes 73a formed outward from both ends of support column fitting portion 72 and penetrating in the thickness direction. Support column 40 is placed inside support column fitting portion 72, and the inner periphery of support column fitting portion 72 abuts approximately halfway around support column 40.

[0040] 17 is an explanatory diagram of the receiving member of FIG. 13, where (a) is a plan view, (b) is a front view, and (c) is a right side view. The receiving member 80 includes a vertical plate portion 81 that is long in the left-right direction, and an upper plate portion 82 and a lower plate portion 83 that extend in the same direction from the upper and lower ends of the vertical plate portion 81, and is formed in a U-shaped vertical cross section. The upper plate portion 82 and the lower plate portion 83 have recesses 84, 85 in the longitudinal center portions that are recessed from the tip side toward the vertical plate portion 81. Furthermore, through holes 81a, 81a are formed at both ends of the vertical plate portion 81 at positions that correspond to the through hole 73a of the fixing portion 73 of the pressing member 71.

[0041] As shown in FIGS. 14 to 16 , the support member 50 has a dovetail groove 51 formed along its longitudinal direction (the left-right direction) that opens toward the receiving member 80. To secure the support member 50 to the support post 40, the head 53 of the bolt member 52 is inserted into the dovetail groove 51 of the support member 50, with the male threaded portion 54 protruding from the opening. Next, the male threaded portion 54 is threaded through the through holes 81a, 81a of the vertical plate portion 81 of the receiving member 80 and the through hole 73a of the fixing portion 73 of the pressing member 71, and a nut member 55 is screwed into the bolt. Since the support post 40 is disposed between the pressing member 71 and the receiving member 80, when the nut member 55 is tightened, the outer periphery of the support post 40 abuts against the inner periphery of the post fitting portion 72 of the pressing member 71 and the left and right corners 84a, 85a of the openings of the recesses 84, 85 of the receiving member 80. At this time, the rear portions of the recesses 84, 85 and the support post 40 are spaced apart. When the nut member 55 is further tightened, the support column 40 is pressed into place by the support column fitting portion 72 and the corner portions 84 a, 85 a on both the left and right sides, so that the support member 50 is fixed to the support column 40 .

[0042] In this embodiment, the recesses 84, 85 are rectangular and consist of side wall portions 84b, 85b and inner portions 84c, 85c that form the recesses 84, 85, and the support pillars 40 are pressed into the corners 84a, 85a on the opening end side of the side wall portions 84b, 85b.

[0043] Here, there is a possibility that the fixing member 70 will rotate relatively around the support 40, but since the contact points at which the support 50 and the receiving member 80 come into contact are corners 84a and 85a, it is possible to expect that a relatively large load will be generated at the contact points due to the biting effect, and it is therefore possible to effectively suppress rotation of the support 50 relative to the support 40. This makes it difficult for the support 50 to rotate relative to the support 40, and it is therefore possible to effectively suppress deviation of the measurement position.

[0044] As described above, the water level sensor 100 according to the present invention comprises a wave transmitting / receiving unit 11 that transmits ultrasonic waves in a predetermined direction and receives reflected waves of the transmitted ultrasonic waves, a housing 20 that houses the wave transmitting / receiving unit 11 and has an opening R formed in a bottom surface 21 through which the ultrasonic waves pass, and a horn 30 that is attached to the housing 20 near the opening R with adhesive T. The horn 30 comprises a horn body 31 that has a small diameter at the top and a large diameter at the bottom, the top of which is inserted into the opening R, and a vertically intermediate portion of the horn body 31. The horn 30 is attached near the opening R and has an annular outer wall portion 34 extending upward from the opening R, and an annular space portion 35 formed between the horn body 31 and the outer wall portion 34. In the horn 30, the gap S1 formed by the lower surface portion 21 and the space 35 is filled with adhesive T, and the outer wall portion 34 has a groove portion 37 at its upper end 34a that leads from the space portion 35 side to the outside, and a through hole 36 at the bottom of the outer wall portion 34 that leads from the space portion 35 side to the outside.

[0045] As a result, when adhesive T is poured into the space 35 and the horn 30 is attached near the opening R of the housing 20, the adhesive T fills the gap S1, and if it can be confirmed that the overflowing adhesive T flows out from the upper groove 37 and the lower through-hole 36, it can be determined that the adhesive T has filled the entire gap S1.

[0046] A gap S2 may be formed between the horn body 31 and the opening R into which the horn body 31 is inserted.

[0047] As a result, part of the excess adhesive T that has filled the gap S1 also fills the gap S2, increasing the adhesive strength between the horn body 31 and the opening R, and the horn 30 is more firmly adhered to the housing 20. [Explanation of symbols]

[0048] 10 Sensor body 11 Transmitting and receiving unit 12 Communications Department 13 Power supply section 14 Control Unit 20 Case 21 Bottom part 22 Lid 23 Protrusion 23a Convex part 30 Horn 31 Horn body 31a top end 32 Cap 33 Sheet material 34 Exterior wall 34a top end 34b Recess 35 Space section 36 Through hole 37 Groove 38 Fitting recess 40 pillars 50 Support material 51 Dovetail groove 52 Bolt material 53 Head 54 Male thread 55 Nut material 60 Connecting member 61 Bottom plate part 62 Side plate part 63 Bolt material 63a head 64 Nut material 65 washer 70 Fixing member 71 Holding member 72 Pillar fitting part 73 Fixed part 73a Through hole 80 Receiving member 81 Vertical plate section 81a Through hole 82 Upper plate 83 Lower plate part 84, 85 recesses 84a, 85a corner 84b, 85b side wall 84c, 85c deep part 100 Water level sensor 200 Water Level Sensor Unit R opening S1, S2 gap T adhesive

Claims

1. a wave transmitting / receiving unit that transmits ultrasonic waves in a predetermined direction and receives reflected waves of the transmitted ultrasonic waves; a housing that houses the wave transmitting and receiving unit and has an opening formed on a bottom surface thereof through which ultrasonic waves pass; a horn attached to the housing near the opening by adhesive; The horn comprises a horn body having a small diameter upper portion and a large diameter lower portion, the upper portion being inserted into the opening, an annular outer wall portion extending upward from a middle portion of the horn body in the vertical direction, and an annular space portion formed between the horn body and the outer wall portion, In the horn attached near the opening, the adhesive is filled in a gap formed between the lower surface portion and the space portion, The outer wall portion has a groove portion at its upper end that leads from the space portion side to the outside, and a through hole at its lower portion that leads from the space portion side to the outside. A water level sensor characterized by:

2. A gap is formed between the horn body and the opening into which the horn body is inserted.

2. The water level sensor according to claim 1.

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