Water level measurement sensor

Abstract

A water level measurement sensor includes a main structure, an ultrasonic probe, and a circuit board. The ultrasonic probe is a closed probe. The edge of the outer surface of the ultrasonic probe transmitting end extends upward to form a peripheral edge. The outer surface of the ultrasonic probe transmitting end is coated with at least one layer of hydrophilic nano-coating. The main structure is cylindrical, and a reflection wall, a reflection surface, an ultrasonic probe accommodating cavity, and a circuit board placement cavity are arranged in the cylindrical body. The ultrasonic probe surface of the present invention is treated with arc edges and nano-coatings, which can effectively prevent the influence of water droplets on the signal after condensation in the central area of ​​the probe.

Description

Technical Field

[0001] The invention relates to the field of ultrasonic distance measurement, and in particular to a water level measurement sensor. Background Art

[0002] Water is an indispensable resource in daily life. When the amount of water suddenly increases, there will be hidden dangers of floods, so water level monitoring is particularly important. There are frequent reports of road flooding due to blockage problems in existing urban underground drainage systems, which seriously affects people's travel. When the drainage system cannot drain the excess water as soon as possible, there may be a risk of waterlogging leading to flooding of underground air-raid shelters and underground commercial streets, which seriously threatens people's life and property safety. Outdoors, water level monitoring of reservoirs and rivers is also very important. When the water level exceeds the warning level, there will be a risk of dam breaches or flooding of nearby rivers. Monitoring the water level allows people to understand the real-time dynamics of the water level and remind people to prepare corresponding solutions before exceeding the water level warning line.

[0003] Existing non-contact measurement methods include radar water level measurement, laser water level measurement, ultrasonic water level measurement, etc. Radar water level measurement is costly, laser water level measurement has high requirements for the working environment, and unstable laser emission will cause unstable water level measurement; the existing ultrasonic water level sensor is installed in the sewer or in the outdoor environment. Due to the high humidity in the air, it is very easy to condense into water droplets on the probe surface. The water droplets are in an arc shape. Under the effect of reflection, the sound wave signal changes, reducing the signal strength and increasing the possibility of mismeasurement. In addition, because the sewer contains various corrosive gases, the product is more easily corroded. Once corroded, the probe will be damaged and the final product cannot be used; and the structure of the whole machine is too complicated, which is not conducive to installation and later maintenance. Summary of the invention

[0004] The purpose of the present invention is to provide a water level measurement sensor, which solves the problems of poor protection performance, inconvenient disassembly, etc.

[0005] The object of the present invention can be achieved by designing a water level measurement sensor, including a main structure, an ultrasonic probe, and a circuit board, wherein the ultrasonic probe is a closed probe;

[0006] The outer surface edge of the ultrasonic probe transmitting end extends upward to form a peripheral edge; the outer surface of the ultrasonic probe transmitting end is coated with at least one layer of hydrophilic nano coating;

[0007] The main structure is cylindrical, and a reflecting wall and a reflecting surface are arranged inside the cylinder. The reflecting wall is in a semicircular arc shape. A through hole is arranged at the bottom of the reflecting wall, and a reflecting surface is arranged above the through hole, which is fixed by a number of supporting columns. The reflecting surface is in a cone shape, and the tip of the cone faces the through hole. The central axis of the reflecting surface coincides with the central axis of the reflecting wall. The ultrasonic probe accommodating cavity is located below the through hole; and a circuit board placement cavity is arranged below the ultrasonic probe accommodating cavity.

[0008] Furthermore, the peripheral edge is an arc-shaped edge.

[0009] Furthermore, the angle between the peripheral edge and the outer surface of the probe end is between 90° and 170°.

[0010] Furthermore, the ultrasonic probe includes a probe housing, a piezoelectric chip, an isolation soft glue, a sponge pad, a PCB board, and a sealant. The piezoelectric chip, the sponge pad, and the PCB board are installed in the probe housing. The piezoelectric chip is arranged at the upper end of the probe housing. The sponge pad is arranged close to the piezoelectric chip. The isolation soft glue is arranged between the sponge pad and the PCB board. The PCB board is connected to the positive and negative electrodes of the piezoelectric chip. The sealant fills the probe housing.

[0011] Furthermore, the outer surface of the probe end is coated with at least one layer of anti-corrosion coating, and the hydrophilic nano coating is coated on the anti-corrosion coating layer; or the hydrophilic nano coating is a hydrophilic anti-corrosion nano coating.

[0012] Furthermore, a heating wire is provided on the probe, and the heating wire is installed outside the probe or inside the probe.

[0013] Furthermore, the heating wire is arranged on the outside of the probe housing, a heating wire fixing groove is arranged around the outside of the probe housing, and the heating wire is placed in the heating wire fixing groove.

[0014] Furthermore, the heating wire is divided into a four-layer structure, the first layer is an insulating layer, the second layer is a heating material layer, the third layer is an insulating layer, and the fourth layer is an adhesive layer.

[0015] Furthermore, a water guide angle for enhancing the water guide effect is provided on the support column, and one side of the support column facing the through hole partially extends toward the probe to form a water guide column, and the front end of the water guide column is between 0.05 and 1 mm away from the probe surface.

[0016] Furthermore, a part of a side of the support column away from the through opening extends upward along the reflective wall to form a water guide eave strip.

[0017] Furthermore, the surfaces of the reflective wall, the reflective surface and the support column are frosted surfaces.

[0018] Furthermore, the surfaces of the reflective wall, the reflective surface and the support column are coated with a hydrophilic nano coating.

[0019] Furthermore, a silicone sleeve is arranged between the ultrasonic probe and the ultrasonic probe accommodating cavity.

[0020] Furthermore, the main structure includes a bell mouth, a stud, a gasket, a potting compound, and a fixing nut. The bell mouth is provided with a reflecting wall and a reflecting surface. The reflecting surface is provided with a supporting column connected to the reflecting wall. The bell mouth is connected to the upper part of the stud. The stud is cylindrical. An ultrasonic probe, a silicone sleeve, a circuit board, and a potting compound are installed in the cylinder. An ultrasonic probe accommodating cavity is provided in the upper inner section of the stud, and a circuit board placement cavity is provided in the lower inner section of the stud. A thread is engraved on the outer upper section of the stud corresponding to the internal thread of the bell mouth. The gasket is installed between the stud and the bell mouth. The fixing nut is screwed on the lower section of the stud. A thread matching the nut is provided on the outer wall of the lower section of the stud.

[0021] Furthermore, the center frequency of the ultrasonic probe is 25~55kHZ, and the diameter is 25±10mm; the distance between the cone point of the reflecting surface and the surface of the probe transmitting end is 0.5±2mm, and the angle between the cone edge and the probe surface is 30±2° when the center of the reflecting surface is perpendicular to the probe; the maximum outer diameter of the reflecting surface is 20±1mm; the wall edge diameter of the reflecting wall is 57.6±1mm; the cavity wall diameter of the ultrasonic probe accommodating cavity is 28.3±1mm; and the cavity wall diameter of the circuit board placement cavity is 21.5±1mm.

[0022] The present invention has arc edge treatment and nano coating treatment on the surface of the ultrasonic probe; the arc edge treatment can effectively gather the water droplets after condensation to the arc edge (water tension), which can effectively avoid the influence of water droplets on the signal after condensation in the central area of ​​the probe; the nano coating treatment can condense the water mist together, reduce the phenomenon of condensation into water droplets alone, and can also reduce the speed of the probe being corroded, and increase the service life of the product; when the surface temperature of the ultrasonic probe is low, it is easy to condense water mist on the probe surface, and the heating wire heats the ultrasonic probe at this time to effectively avoid the condensation of water mist on the probe surface; when water droplets condense on the probe surface and affect the signal, the working power of the heating wire can be increased to provide a higher temperature to evaporate the water droplets. The present invention adopts a reflective energy gathering structure, and the energy is reflected and gathered to the reflection surface through the horn mouth after transmission, so that the energy is more concentrated and the angle is smaller. The reflection surface also reduces the area directly exposed to the ultrasonic probe, and reduces the probability of dirt directly splashing onto the probe surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a structural cross-section of a preferred embodiment of the present invention;

[0024] Figure 2 is a schematic diagram of a preferred embodiment of the present invention;

[0025] Figure 3 It is an exploded schematic diagram of a preferred embodiment of the present invention;

[0026] Figure 4is a schematic diagram of a probe of a preferred embodiment of the present invention;

[0027] Figure 5 Schematic diagram of the number of layers of the heating wire of a preferred embodiment of the present invention;

[0028] Figure 6 is a block diagram of a circuit board of a preferred embodiment of the present invention;

[0029] Figure 7 It is a schematic diagram of an application example of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with embodiments.

[0031] In this specification and claims, the terms "upper" and "lower" are used as Figure 1 The positions of the embodiments shown are taken as examples.

[0032] like Figure 1 , Figure 3 , Figure 4 As shown, a water level measurement sensor includes a main structure, an ultrasonic probe 4, and a circuit board 6. The circuit board 6 is provided with an anti-static circuit 61, a temperature detection circuit 62, a heating wire control circuit 63, a boost excitation pulse circuit 64, an amplification control circuit 65, a signal amplification circuit 66, a signal shaping circuit 67, and a processor 68; the ultrasonic probe 4 is a closed probe, including a probe housing 40, a piezoelectric chip 41, an isolation soft glue 49, a sponge pad 42, a PCB board 43, and a sealant 45. The piezoelectric chip 41, the sponge pad 42, the isolation soft glue 49, and the PCB board 43 are installed in the probe housing 40, the piezoelectric chip 41 is arranged at the upper end of the probe housing 40, the sponge pad 42 is arranged close to the piezoelectric chip 41, the isolation soft glue 49 is arranged between the sponge pad 41 and the PCB board 43, and the PCB board 43 is connected to the positive and negative electrodes of the piezoelectric chip 41; the sealant 45 fills the probe housing 40.

[0033] The outer surface edge of the ultrasonic probe transmitting end extends upward to form a peripheral edge 46 ; the outer surface of the ultrasonic probe transmitting end is coated with at least one layer of hydrophilic nano coating 44 .

[0034] The main structure is cylindrical, and a reflecting wall and a reflecting surface 12 are arranged inside the cylinder. The reflecting wall is in a semicircular arc shape; a through hole is arranged at the bottom of the reflecting wall, and a reflecting surface 12 is arranged above the through hole, which is fixed by a number of supporting columns 11. The reflecting surface 12 is in a cone shape, and the tip of the cone faces the through hole, and the central axis of the reflecting surface 12 coincides with the central axis of the reflecting wall; below the through hole is an ultrasonic probe accommodating cavity; below the ultrasonic probe accommodating cavity is a circuit board placement cavity.

[0035] like Figure 4As shown, the peripheral edge 46 is an arc-shaped edge. The included angle a between the peripheral edge 46 and the outer surface of the probe end is between 90° and 170°.

[0036] The outer surface of the probe end is coated with at least one layer of anti-corrosion coating, and the hydrophilic nano coating 44 is coated on the anti-corrosion coating layer; or the hydrophilic nano coating 44 is a hydrophilic anti-corrosion nano coating.

[0037] The probe 4 is provided with a heating wire 3, which is installed outside or inside the probe. The heating wire 3 is arranged outside the probe housing 40, and a heating wire fixing groove 47 is arranged around the outside of the probe housing, and the heating wire 3 is placed in the heating wire fixing groove 47. Figure 5 As shown, the heating wire 3 is divided into a four-layer structure, the first layer is the first insulating layer, the second layer is the heating material layer, the third layer is the second insulating layer, and the fourth layer is the bonding layer. In this embodiment, the first insulating layer and the second insulating layer are made of polyimide film with a thickness of 0.02-0.15 mm, and 0.05 mm in this embodiment; the heating layer is made of iron and aluminum with a thickness of 0.15-0.2 mm, and 0.18 mm in this embodiment; the bonding layer is made of double-sided adhesive 3M adhesive with a thickness of 0.03-0.2 mm, and 0.1 mm in this embodiment.

[0038] The support column 11 is provided with a water guide angle 19 for enhancing the water guide effect, and the side of the support column 11 facing the through hole partially extends toward the probe direction to form a water guide column 13, and the front end of the water guide column 13 is between 0.05 and 1 mm away from the probe surface. The side of the support column 11 away from the through hole partially extends upward along the reflective wall to form a water guide eaves 17.

[0039] The surfaces of the reflective wall, the reflective surface and the support column are frosted surfaces. The frosted surfaces have a better water diversion effect and accelerate the drainage of surface water.

[0040] The surfaces of the reflective wall, the reflective surface and the support column are coated with a hydrophilic nano coating or a hydrophobic nano coating, so that accumulated water is not easily retained on the surfaces of the reflective wall, the reflective surface and the support column.

[0041] A silicone sleeve 5 is arranged between the ultrasonic probe 4 and the ultrasonic probe accommodating cavity to prevent the ultrasonic probe 4 from contacting the cavity wall, thereby playing an isolation and buffering role.

[0042] The center frequency of the ultrasonic probe is 25~55kHZ, and the diameter is 25±10mm; the distance between the cone point of the reflecting surface and the surface of the probe transmitting end is 0.5±2mm, and the angle between the cone edge and the probe surface is 30±2° when the center of the reflecting surface is perpendicular to the probe; the maximum outer diameter of the reflecting surface is 20±1mm; the wall edge diameter of the reflecting wall is 57.6±1mm; the cavity wall diameter of the ultrasonic probe accommodating cavity is 28.3±1mm; and the cavity wall diameter of the circuit board placement cavity is 21.5±1mm.

[0043] like Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, the main structure of the water level measurement sensor includes a bell mouth 1, a stud 7, a washer 2, and a fixing nut 8. The bell mouth 1 is connected to the upper part of the stud 7. The bell mouth 1 is in a trumpet shape and coated with a hydrophilic nano coating. A reflective surface 12 is provided inside. The inner wall of the bell mouth is a reflective wall to achieve energy reflection. The reflective surface 12 is in a cone shape to achieve energy reflection and aggregation, which can prevent some water vapor from condensing on the probe 4 and prevent dirt from splashing directly onto the probe surface.

[0044] A support column 11 connected to the inner wall of the bell mouth is provided on the reflecting surface 12; a water guide column 13 is provided on the support column 11, and the water guide column 13 does not contact the ultrasonic probe 4, and the support column 11 is claw-shaped; under the action of the hydrophilic coating, the wetting angle of the surface of the ultrasonic probe 4 becomes smaller, and the water mist is easier to gather. Under the action of the hydrophilic coating, the wetting angle of the surface of the bell mouth becomes smaller, and the fluidity of water becomes higher; the condensed water mist will also flow from the edge of the probe through the water guide column 13 to the water guide angle 19 of the support column 11, and then flow to the lowest point through the support column 11 through the water guide eaves 17 and finally fall.

[0045] like Figure 1 , Figure 2 As shown, the stud 7 is cylindrical and is used to install the ultrasonic probe 4, the silicone sleeve 5, the circuit board 6, and the potting glue 72. The upper outer wall of the stud 7 is provided with a thread corresponding to the inner thread of the bell mouth. The inside of the stud is provided with a grounding port 71 connected to the negative pole of the circuit board, which can be connected to the metal shell to improve the anti-interference ability of the product.

[0046] The washer 2 is installed between the stud 7 and the bell mouth 1 to fill the irregularities of the machined surface, prevent loosening and protect the device.

[0047] like Figure 4As shown, the ultrasonic probe 4 is a closed probe, including a piezoelectric chip 41, a sponge pad 42, an isolation soft glue 49, a PCB board 43, and a sealant 45. The surface of the ultrasonic probe is also coated with a hydrophilic anti-corrosion nano coating 44, which condenses the small water mist together and also reduces the effect of external corrosion; the edge of the surface of the ultrasonic probe is in an arc shape, which attracts the condensed water mist to the outer edge. The piezoelectric chip 41 completes the transmission and reception of ultrasonic waves by the piezoelectric effect. The isolation soft glue 49 prevents the sealant from continuing to penetrate into the sponge pad 42 to ensure the damping effect of the sponge pad 42; the sponge pad 42 damps the vibration of the piezoelectric chip 41 and absorbs the ultrasonic waves from the piezoelectric chip 41 to the back. The PCB board 43 connects the positive and negative poles of the piezoelectric chip 41 to ensure the consistency of the lead wire. The sealant 45 completes the sealing of the ultrasonic probe 4 and enhances the waterproof performance of the probe 4.

[0048] The heating wire 3 is installed on the ultrasonic probe 4 in a strip shape. The heating wire 3 heats the ultrasonic probe to remove small water mist on the probe surface and prevents the small water mist from condensing on the ultrasonic probe surface.

[0049] The silicone sleeve 5 wraps the ultrasonic probe 4 and the heating wire 3 and is installed in the ultrasonic probe accommodating cavity to prevent the ultrasonic probe 4 from contacting the cavity wall, thereby playing an isolation and buffering role.

[0050] like Figure 6 As shown, the circuit board 6 includes an anti-static circuit 61, a temperature detection circuit 62, a heating control circuit 63, a boost excitation pulse circuit 64, an amplification control circuit 65, a signal amplification circuit 66, a signal shaping circuit 67, and a processor 68; the anti-static circuit 61 protects the processor 68 and prevents static electricity from entering the processor 68; the temperature detection circuit 62 completes the collection of the external temperature; the heating control circuit 63 completes the control of the working current and heating power of the heating wire 3; the boost excitation circuit 64 completes the drive of the ultrasonic probe 4 to emit ultrasonic waves; the amplification control circuit 65 completes the adjustment of the amplification gain; the signal amplification circuit 66 receives ultrasonic echoes to realize the signal amplification function; the signal shaping circuit 67 completes the shaping of the echo analog signal into a data signal and provides it to the processor 68; the processor 68 completes instruction issuance, signal collection, signal processing, and signal output.

[0051] like Figure 1 As shown, the potting glue 72 is potted in the inner cavity of the ultrasonic probe 4 and the stud 7 to seal the ultrasonic probe 4 and the circuit board 6. The sealant 45 used to seal the ultrasonic probe can be the same as or different from the potting glue 72 used to pot the stud.

[0052] The fixing nut 8 is screwed onto the stud 7, and a thread matching the nut is provided on the outer wall of the lower section of the stud.

[0053] During production, first spray the surface of the ultrasonic probe 4 with a hydrophilic nano coating 44, then install the heating wire 3 on the ultrasonic probe 4, put the ultrasonic probe 4 into the silicone sleeve 5, and connect the positive and negative electrodes of the ultrasonic probe and the heating wire to the circuit board 6; install the connected circuit board 6 in the stud 7, pour in the potting glue 72, and wait for the potting glue 72 to solidify; install the washer 2 on the upper part of the stud and tighten the bell mouth 1; screw on the nut 8 to complete the assembly.

[0054] The working process of the water level measurement sensor is as follows: the module is powered on to supply power to each circuit; the processor 68 detects the input voltage and controls the working time of the heating wire 3; the processor 68 sends instructions to the boost excitation pulse circuit 64 and the amplification control circuit 65; the probe 4 sends and receives sound wave signals after working; the weak sound wave signal is amplified by the signal amplification circuit 66; the amplification control circuit 65 adjusts the amplification; the amplified signal is shaped by the signal shaping circuit 67 and returned to the processor 68; the temperature detection circuit 62 detects the external ambient temperature and feeds it back to the processor 68; the processor 68 identifies the time when the echo returns and combines it with the external ambient temperature to perform temperature compensation and calculate the distance value; the processor 68 transmits the calculated data signal to the client through the connecting line and returns it.

[0055] like Figure 7 As shown, the application case is to install the product C of the present invention at the wellhead of the sewer, where a drainage pipe D and a sewage pipe F are provided, and the product C is used to measure the liquid level of the sewage E in the well. The product C is installed below the wellhead cover A of the sewer wellhead. When installing, it is only necessary to tighten the product C on the fixing bracket B and connect the product C to the customer's wellhead to work. The fixing bracket B can be fixed on the well wall or on the well cover A.

[0056] The present invention adopts a reflective energy gathering structure. After the energy is transmitted, it is reflected by the horn mouth and gathered to the reflecting surface, so that the energy is more concentrated and the angle is smaller. The reflecting surface also reduces the area directly exposed to the ultrasonic probe and reduces the probability of dirt splashing directly onto the probe surface.

[0057] The surface of the ultrasonic probe of the present invention is treated with arc edge and nano coating; the arc edge treatment can effectively gather the condensed water droplets to the arc edge (water tension), which can effectively avoid the influence of water droplets on the signal after condensation in the middle area of ​​the probe; the nano coating treatment can condense the water mist together, reduce the phenomenon of condensation into water droplets alone, and also reduce the speed of the probe being corroded, thereby increasing the service life of the product; when the surface temperature of the ultrasonic probe is low, it is easy to condense water mist on the probe surface, and the heating wire heats the ultrasonic probe at this time, which can effectively avoid the condensation of water mist on the probe surface; when water droplets condense on the probe surface and affect the signal, the working power of the heating wire can be increased to provide a higher temperature to evaporate the water droplets. The waterproof effect can reach IP68 level.

[0058] Compared with other products, the present invention has a simpler and more compact structure. During installation, you only need to connect the device and tighten the nut. Normal data output indicates that the installation is complete. For later maintenance, you only need to unscrew the nut to perform maintenance, thereby reducing unnecessary operations, reducing labor costs, and enhancing work efficiency.

Claims

1. A water level measurement sensor, comprising a main structure, an ultrasonic probe, and a circuit board, wherein the ultrasonic probe is a closed probe; characterized in that: The outer surface edge of the ultrasonic probe transmitting end extends upward to form a peripheral edge; the outer surface of the ultrasonic probe transmitting end is coated with at least one layer of hydrophilic nano coating; The main structure is in the shape of a cylinder, and a reflecting wall and a reflecting surface are arranged inside the cylinder, and the reflecting wall is in the shape of a semicircular arc; a through hole is arranged at the bottom of the reflecting wall, and a reflecting surface is arranged above the through hole, which is fixed by a plurality of supporting columns, and the reflecting surface is in the shape of a cone, and the cone tip faces the through hole, and the central axis of the reflecting surface coincides with the central axis of the reflecting wall; the ultrasonic probe accommodating cavity is arranged below the through hole; and a circuit board placement cavity is arranged below the ultrasonic probe accommodating cavity; The support column is provided with a water guide angle to enhance the water guide effect. The side of the support column facing the through hole partially extends toward the probe to form a water guide column, and the front end of the water guide column is between 0.05 and 1 mm away from the probe surface.

2. The water level measurement sensor according to claim 1, characterized in that: The peripheral edge is an arc-shaped edge.

3. The water level measurement sensor according to claim 1 or 2, characterized in that: The included angle between the peripheral edge and the outer surface of the probe end is between 90° and 170°.

4. The water level measurement sensor according to claim 1, characterized in that: The ultrasonic probe includes a probe housing, a piezoelectric chip, an isolation soft glue, a sponge pad, a PCB board, and a sealant. The piezoelectric chip, the sponge pad, and the PCB board are installed in the probe housing. The piezoelectric chip is arranged at the upper end of the probe housing, the sponge pad is arranged close to the piezoelectric chip, the isolation soft glue is arranged between the sponge pad and the PCB board, and the PCB board is connected to the positive and negative poles of the piezoelectric chip; the sealant fills the probe housing.

5. The water level measurement sensor according to claim 1, characterized in that: The outer surface of the probe end is coated with at least one layer of anti-corrosion coating, and the hydrophilic nano coating is coated on the anti-corrosion coating layer; or, the hydrophilic nano coating is a hydrophilic anti-corrosion nano coating.

6. The water level measurement sensor according to claim 1, characterized in that: The probe is provided with a heating wire, which is installed outside or inside the probe; a heating control circuit is provided on the circuit board, the control end of the heating control circuit is connected to the processor, and the output end of the heating control circuit is connected to the heating wire.

7. The water level measurement sensor according to claim 6, characterized in that: The heating wire is arranged on the outside of the probe shell, a heating wire fixing groove is arranged around the outside of the probe shell, and the heating wire is placed in the heating wire fixing groove.

8. The water level measurement sensor according to claim 6 or 7, characterized in that: The heating wire is divided into four layers: the first layer is the first insulating layer, the second layer is the heating material layer, the third layer is the second insulating layer, and the fourth layer is the adhesive layer.

9. The water level measurement sensor according to claim 1, characterized in that: A part of one side of the support column away from the through opening extends upward along the reflecting wall to form a water guide eave strip.

10. The water level measurement sensor according to claim 1, characterized in that: The surfaces of the reflective wall, the reflective surface and the support column are frosted surfaces.

11. The water level measurement sensor according to claim 1, characterized in that: The surfaces of the reflective wall, the reflective surface and the support column are coated with a hydrophilic nano coating.

12. The water level measurement sensor according to claim 1, characterized in that: A silicone sleeve is arranged between the ultrasonic probe and the ultrasonic probe accommodating cavity.

13. The water level measurement sensor according to claim 1, characterized in that: The main structure includes a bell mouth, a stud, a gasket, a potting compound, and a fixing nut. The bell mouth is provided with a reflecting wall and a reflecting surface. The reflecting surface is provided with a supporting column connected to the reflecting wall. The bell mouth is connected to the upper part of the stud. The stud is cylindrical, and an ultrasonic probe, a silicone sleeve, a circuit board, and a potting compound are installed in the cylinder. An ultrasonic probe accommodating cavity is arranged in the upper part of the stud, and a circuit board placement cavity is arranged in the lower part of the stud. A thread is engraved on the outer upper part of the stud corresponding to the internal thread of the bell mouth. The gasket column is installed between the stud and the bell mouth. The fixing nut is screwed on the lower part of the stud, and a thread matching the nut is arranged on the outer wall of the lower part of the stud.

14. The water level measurement sensor according to claim 1, characterized in that: The center frequency of the ultrasonic probe is 25~55kHZ, and the diameter is 25±10mm; the distance between the cone point of the reflecting surface and the surface of the probe transmitting end is 0.5±2mm, and the angle between the cone edge and the probe surface is 30±2° when the center of the reflecting surface is perpendicular to the probe; the maximum outer diameter of the reflecting surface is 20±1mm; the wall edge diameter of the reflecting wall is 57.6±1mm; the cavity wall diameter of the ultrasonic probe accommodating cavity is 28.3±1mm; and the cavity wall diameter of the circuit board placement cavity is 21.5±1mm.

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