Single-ultrasonic-head sensor for measuring liquid density and liquid level height

Abstract

The invention discloses a single-ultrasonic-head sensor for measuring liquid density and liquid level height, which relates to the technical field of liquid level measurement and comprises a floater component, a reflection cavity component and an ultrasonic sensor component. The floater assembly is assembled on the reflection cavity assembly, the reflection cavity assembly is connected with the ultrasonic sensor assembly, and the ultrasonic sensor assembly is connected with the floater assembly through the reflection cavity assembly. High-frequency ultrasonic waves are transmitted and received through a single point, the sound velocity (density) and the ultrasonic wave return time difference (liquid level) are synchronously analyzed, the density and the liquid level of the urea solution are calculated, the problems of mechanical interference and data splitting are avoided, and the trepanning and cable cost is reduced; the shared high-precision temperature compensation module directly eliminates compensation deviation of the split system, and maintenance only needs single-point anti-crystallization treatment; and in combination with a cross validation algorithm (density liquid level logic mutual verification), the operation and maintenance cost is reduced while the data reliability is improved, and the method is particularly suitable for space-limited and highly-corrosive urea solution detection scenes.

Description

Technical Field

[0001] This invention relates to the field of liquid level measurement technology, and more specifically, to a sensor for measuring liquid density and liquid level height using a single ultrasonic head. Background Technology

[0002] To meet the China VI emission standards, diesel engines commonly employ SCR (Selective Catalytic Reduction) technology to treat exhaust gases. In this system, urea solution acts as a reducing agent, reacting chemically with nitrogen oxides (including NO and NO2) in the exhaust gas to ultimately produce harmless nitrogen and water, effectively reducing pollutant emissions. To ensure the purification effect of the SCR system, the mass concentration of the urea solution must be strictly controlled near the standard value of 32.5%. When the concentration deviates from the allowable range, the system must promptly issue a warning signal. Furthermore, the solution level in the urea storage tank must be monitored in real time. When the level drops below the preset warning line, the system should trigger an alarm function to remind operators to replenish the urea solution promptly.

[0003] The density of urea solution is usually determined by ultrasonic method or refractive index method.

[0004] 1. Ultrasonic method for detecting the density of urea solution (i.e., utilizing the physical relationship between the propagation speed of ultrasound in urea solution and density). Changes in urea concentration alter the propagation speed of ultrasound waves in a solution; higher concentrations result in faster sound speeds. The sensor calculates the real-time density value by precisely measuring the time difference between ultrasound transmission and reception, combined with a temperature compensation algorithm. However, this approach has drawbacks: measurement accuracy is susceptible to variations in solution flow rate, bubbles, suspended matter, and internal acoustic properties of the liquid (such as viscosity); initial equipment costs are relatively high; under extreme conditions (such as violent shaking or the presence of abundant foam), the signal may be unstable or attenuated, leading to measurement failure; furthermore, its installation and commissioning typically require specialized knowledge to ensure the ultrasound path and signal quality.

[0005] 2. The density of urea solution is determined by the refractive index method (i.e., based on the change in the angle of refraction of light as it passes through the urea solution). Urea concentration has a linear relationship with refractive index. The sensor emits infrared light and detects the refraction angle, converting it into a density value. The drawbacks of this method are that it requires high solution purity; bubbles, impurities, or crystals can significantly interfere with measurement accuracy. Furthermore, it relies on a temperature compensation mechanism (the refractive index of urea solution is easily affected by temperature), and inaccurate temperature control can lead to inaccurate results. Additionally, this method is not applicable to non-transparent or highly corrosive urea solution variants, limiting its application scope.

[0006] The liquid level of urea solution is usually measured using methods such as capacitive level sensors, ultrasonic level sensors, or magnetostrictive level gauges.

[0007] 1. Capacitive level sensor measures the level of urea solution (i.e., the capacitive level sensor detects the change in dielectric constant between electrodes caused by the change in urea solution level, converts the level height into a change in capacitance, and then retrieves the level data in real time). The drawback of this approach is that it is susceptible to interference from the urea crystal layer on the electrode surface. Crystallization can cause capacitance drift and lead to continuous measurement deviations. At the same time, changes in the conductivity of the urea solution (such as the infiltration of impurities) or temperature and ultrasonic fluctuations can significantly affect the stability of the dielectric constant, requiring additional compensation algorithms. Furthermore, the metal electrodes of the sensor are prone to corrosion during long-term use, and high-viscosity solutions may cause adhesion errors, requiring frequent maintenance and calibration to ensure accuracy.

[0008] 2. Ultrasonic liquid level sensor measures the liquid level of urea solution (i.e., by emitting high-frequency ultrasonic waves into the urea solution and accurately measuring the propagation time difference of the ultrasonic waves from emission to reflection back to the receiving probe, and combining the propagation speed of ultrasonic waves in the urea medium, the liquid level height is calculated in real time). The drawbacks of this approach are that the foam or crystal layer can scatter or absorb ultrasonic waves, leading to the loss or distortion of the returned ultrasonic signal. Changes in urea density at high temperatures affect the accuracy of the sound velocity, requiring real-time temperature compensation. Strong vibrations or complex tank structures can easily cause interference with the returned ultrasonic waves. Furthermore, urea crystals in low-temperature environments may cover the probe, requiring frequent maintenance and relying on high-precision signal processing algorithms to ensure reliability.

[0009] 3. Magnetostrictive level gauge measures the level of urea solution (i.e., by moving a magnetic float with the urea solution level, disturbing the magnetic field of the ultrasonic guide wire, triggering a current pulse and detecting the time difference between the magnetostrictive torsional ultrasonic waves, and accurately calculating the liquid level height). The drawbacks of this approach are that the magnetic float is susceptible to jamming due to urea crystals or adhesion of high-viscosity impurities, leading to measurement failure; the violent temperature changes in ultrasonic waves affect the torsional ultrasonic wave propagation speed in the ultrasonic guide wire, requiring dynamic compensation; the installation must be strictly vertical, as a tilt exceeding 3° will produce significant errors, and the strong electromagnetic environment interferes with the timing of the pulse signal; long-term contact with urea solution may corrode the metal sheath of the ultrasonic guide wire, requiring frequent cleaning and maintenance and relying on redundant design to ensure reliability.

[0010] As can be seen from the above, existing methods for detecting the density and level of urea solutions typically use two ultrasonic sensors to measure the density and level of the urea solution separately, or use an infrared sensor to measure the density and an ultrasonic sensor to measure the level. The drawbacks of this approach are that using a dual-probe measurement scheme (such as ultrasonic + ultrasonic or infrared + ultrasonic combination) requires drilling two independent mounting holes in the urea tank, significantly increasing the risk of seal failure and media leakage; the density probe needs to be immersed in the solution for measurement (infrared methods require a clean, crystal-free light window, and ultrasonic immersion methods require protection against air bubble interference), while the level probe is sensitive to the installation location and liquid surface condition; independent calibration of the two systems leads to asynchronous temperature compensation (the density and level measurement errors are higher when the urea solution is under a temperature gradient); more seriously, both probes require frequent maintenance in crystallization environments, resulting in higher maintenance costs and a greater risk of downtime. Therefore, how to achieve dual-parameter detection of density and level using a single probe, simplifying the system structure and reducing installation and maintenance costs, is the technical problem this invention aims to solve. Summary of the Invention

[0011] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0012] To at least partially solve the above problems, the present invention provides a sensor for measuring liquid density and liquid level height using a single ultrasonic head, comprising: a float assembly, a reflective cavity assembly, and an ultrasonic sensor assembly; the float assembly is mounted on the reflective cavity assembly, the reflective cavity assembly and the ultrasonic sensor assembly are connected, and the ultrasonic sensor assembly is connected to the float assembly through the reflective cavity assembly; The float assembly changes with the liquid level and has the function of reflecting ultrasonic waves; The reflective cavity assembly splits the ultrasonic waves into two paths: one path is used to measure liquid density, and the other path is used to measure liquid level. The ultrasonic sensor assembly is used to emit, receive, and analyze ultrasonic waves.

[0013] Preferably, the reflective cavity assembly consists of a guide tube, a cover, a first reflective sheet, and a reflective cavity; The guide tube is disposed on the reflective cavity and communicates with the interior of the reflective cavity. The float assembly is assembled on the guide tube, and the guide tube is used to provide guidance for the float assembly. The reflective cavity is provided with an exhaust hole for discharging air bubbles; The ultrasonic sensor assembly is disposed at one end of the reflecting cavity, and the cover is disposed at the end of the reflecting cavity away from the ultrasonic sensor assembly. The first reflective sheet is disposed within the reflective cavity and located between the ultrasonic sensor assembly and the cover; Both the cover and the first reflective sheet have the function of reflecting ultrasonic waves; The first reflector divides the ultrasonic waves into two paths: one path contacts the cap to measure the liquid density, and the other path contacts the first reflector to measure the liquid level.

[0014] Preferably, the first reflector has a through hole.

[0015] Preferably, the reflective cavity is a tubular structure, the cover and the ultrasonic sensor assembly are located at opposite ends of the reflective cavity, the guide tube is vertically disposed on the side wall of the reflective cavity, and the central axis of the guide tube is perpendicular to the central axis of the reflective cavity.

[0016] Preferably, the reflecting cavity consists of an outer reflecting cavity and an inner reflecting cavity; Both the guide tube and the first reflective sheet are disposed on the outer reflective cavity, with the guide tube located outside the outer reflective cavity and the first reflective sheet located inside the outer reflective cavity; The cover and the ultrasonic sensor assembly are disposed on the inner reflective cavity.

[0017] Preferably, the inner reflective cavity is a tubular structure, the cover and the ultrasonic sensor assembly are respectively disposed at both ends of the inner reflective cavity, the top of the inner reflective cavity is provided with an installation port, and the outer reflective cavity is connected to the inner reflective cavity through the installation port.

[0018] Preferably, the outer reflective cavity has an arc-shaped structure, and the inner diameter of the arc-shaped structure is adapted to the inner diameter of the inner reflective cavity. The outer reflective cavity is provided with a connecting end and a mounting end. The connecting end is located on the convex side of the outer reflective cavity, and the mounting end is located on the concave side of the outer reflective cavity. The connecting end and the mounting end are connected. The guide tube is connected to the outer reflective cavity through the connecting end, and the first reflective sheet is disposed on the mounting end.

[0019] Preferably, the ultrasonic sensor assembly consists of an ultrasonic sensor, a protective tube, a pagoda-shaped connector, and a housing; The ultrasonic sensor is housed inside the housing and is used to emit, receive, and analyze ultrasonic waves to calculate the density and level of the urea solution. The protective tube is connected to the pagoda-shaped connector on the outer casing to protect the circuitry of the ultrasonic sensor from corrosion by urea solution.

[0020] Preferably, the float assembly consists of a float and a second reflector. The float is mounted on the guide tube and is movably connected to the guide tube. When the liquid level changes, the float moves along the guide tube as the liquid level changes. The second reflector is disposed at the bottom of the float, opposite to the first reflector, and the second reflector has the function of reflecting ultrasonic waves.

[0021] Preferably, the float is provided with a limiting structure, and the guide tube is provided with a matching structure. The limiting structure and the matching structure cooperate to limit the float in the horizontal direction.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: This invention employs a single-probe measurement scheme, transmitting and receiving high-frequency ultrasonic waves at a single point, simultaneously analyzing the sound velocity (density) and the return ultrasonic wave time difference (liquid level), and calculating the density and liquid level of the urea solution. This avoids mechanical interference and data fragmentation issues, reducing the cost of openings and cables. The shared high-precision temperature compensation module directly eliminates compensation deviations in the split system, and maintenance only requires single-point anti-crystallization treatment. Combined with a cross-validation algorithm (density and liquid level logical mutual verification), it improves data reliability while reducing operation and maintenance costs, making it particularly suitable for urea solution detection scenarios with limited space and strong corrosion.

[0023] The sensor for measuring liquid density and liquid level height using a single ultrasonic head as described in this invention, other advantages, objectives and features of the invention will be apparent in part from the following description, and in part will be understood by those skilled in the art through study and practice of the invention. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the sensor for measuring liquid density and liquid level height using a single ultrasonic head, as described in this invention.

[0025] Figure 2 for Figure 1 Exploded view.

[0026] Figure 3 for Figure 2 Exploded view.

[0027] Figure 4 This is a cross-sectional view of the single ultrasonic head sensor for measuring liquid density and liquid level height according to the present invention.

[0028] Figure 5This is a schematic cross-sectional view of the sensor for measuring liquid density and liquid level height using a single ultrasonic head, as described in this invention.

[0029] Figure 6 This is a cross-sectional view of another embodiment of the present invention.

[0030] Figure 7 This is a schematic diagram of ultrasonic wave interference.

[0031] Figure 8 This is a schematic diagram of the absorption layer.

[0032] Figure 9 This is a schematic diagram showing the location of the crystal removal structure.

[0033] Figure 10 for Figure 9 A schematic diagram of the crystal removal structure.

[0034] Figure 11 This is a schematic diagram of a crystal removal structure.

[0035] In the figure: 1 float assembly, 11 float, 12 second reflector, 2 reflector cavity assembly, 21 guide tube, 22 cover, 23 first reflector, 24 outer reflector cavity, 241 connecting end, 242 mounting end, 25 inner reflector cavity, 3 ultrasonic sensor assembly, 31 ultrasonic sensor, 32 protective tube, 33 pagoda head, 34 outer shell, 4 absorption layer, 5 crystal removal structure, 51 storage container, 52 scraper, 53 boss, 54 feed hole. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0037] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0038] like Figures 1-11 As shown, the present invention provides a sensor for measuring liquid density and liquid level height using a single ultrasonic head, comprising: a float assembly 1, a reflective cavity assembly 2, and an ultrasonic sensor assembly 3; the float assembly 1 is mounted on the reflective cavity assembly 2, the reflective cavity assembly 2 and the ultrasonic sensor assembly 3 are connected, and the ultrasonic sensor assembly 3 is connected to the float assembly 1 through the reflective cavity assembly 2; The float assembly 1 can change with the liquid level and has the function of reflecting ultrasonic waves; The reflective cavity assembly 2 can split the ultrasonic waves emitted by the ultrasonic sensor assembly 3 into two paths. One ultrasonic wave travels back and forth within the reflective cavity assembly 2 to measure the liquid density. The ultrasonic sensor assembly 3 calculates the real-time density value by accurately measuring the time difference between ultrasonic wave emission and reception, combined with a temperature compensation algorithm. The other ultrasonic wave is reflected by the reflective cavity assembly 2 to the float assembly 1, then reflected back to the reflective cavity assembly 2 via the float assembly 1, and finally returns to the ultrasonic sensor assembly 3 to measure the liquid level height. The ultrasonic sensor assembly 3 calculates the liquid level height in real time by accurately measuring the time difference between ultrasonic wave emission and reception, combined with the propagation speed of ultrasonic waves in the urea medium. The ultrasonic sensor assembly 3 is used to transmit, receive, and analyze ultrasonic waves.

[0039] Existing methods for detecting the density and level of urea solutions typically employ two ultrasonic sensors to measure the density and level of the urea solution separately, or use an infrared sensor to measure the density and an ultrasonic sensor to measure the level. This invention, however, achieves a two-in-one ultrasonic sensor measurement of urea solution density and level. Its core advantage lies in the simultaneous, non-contact, dual-parameter detection using a single ultrasonic probe: the level height is calculated by analyzing the time difference between ultrasonic waves, and the strong correlation between sound velocity and density (changes in urea solution density significantly alter sound velocity), combined with temperature compensation, is used to retrieve the density value. This significantly simplifies the system structure, reduces installation and maintenance costs, avoids the risk of crystallization contamination caused by media contact, and improves the reliability and real-time performance of industrial deployments.

[0040] Furthermore, this invention employs a single-probe measurement scheme, which transmits and receives high-frequency ultrasonic waves at a single point, simultaneously analyzing the sound velocity (density) and the time difference of the returned ultrasonic waves (liquid level), and calculating the density and liquid level of the urea solution. This avoids mechanical interference and data fragmentation issues, and reduces the cost of opening holes and cables. The shared high-precision temperature compensation module directly eliminates the compensation deviation of the split system, and maintenance only requires single-point anti-crystallization treatment. Combined with a cross-validation algorithm (density and liquid level logical mutual verification), it improves data reliability while reducing operation and maintenance costs, making it particularly suitable for urea solution detection scenarios with limited space and strong corrosion.

[0041] The reflective cavity assembly 2 consists of a guide tube 21, a cover 22, a first reflective sheet 23, and a reflective cavity; The guide tube 21 is disposed on the reflective cavity and communicates with the interior of the reflective cavity. The float assembly 1 is assembled on the guide tube 21. The guide tube 21 is used to provide guidance for the float assembly 1. When the liquid level changes, the float assembly 1 can move with the liquid surface on the guide tube 21. The reflective cavity is provided with an exhaust hole for discharging air bubbles; The ultrasonic sensor assembly 3 is disposed at one end of the reflecting cavity, and the cover 22 is disposed at the end of the reflecting cavity away from the ultrasonic sensor assembly 3. The first reflector 23 is disposed in the reflection cavity and located between the ultrasonic sensor assembly 3 and the cover 22. The first reflector 23 is usually inclined, preferably at a 45-degree angle, so as to reflect the ultrasonic waves to the float assembly 1 and the ultrasonic sensor assembly 3. Both the cover 22 and the first reflective sheet 23 have the function of reflecting ultrasonic waves; The first reflector 23 splits the ultrasonic waves into two paths. One path of the ultrasonic waves does not contact the first reflector 23 but directly contacts the cover 22 and is reflected back to the ultrasonic sensor assembly 3 through the cover 22 to measure the liquid density. The other path of the ultrasonic waves contacts the first reflector 23, is reflected to the float assembly 1, and is then reflected back to the first reflector 23 by the float assembly 1. Finally, it is reflected back to the ultrasonic sensor assembly 3 through the first reflector 23 to measure the liquid level height.

[0042] As one embodiment of splitting ultrasonic waves into two paths, the first reflective sheet 23 is provided with a through hole, the central axis of which is located at the center of the cover 22 and perpendicular to the cover 22, such as... Figure 4 and Figure 5 As shown, this allows the ultrasonic waves to act directly on the center of the cover 22 after passing through the through hole and the first reflector 23, and then return along the original path.

[0043] Furthermore, the reflecting cavity is a tubular structure, with the cover 22 and the ultrasonic sensor assembly 3 located at opposite ends of the reflecting cavity, as shown below. Figure 4 As shown, the guide tube 21 is arranged vertically on the side wall of the reflective cavity, and the central axis of the guide tube 21 is perpendicular to the central axis of the reflective cavity.

[0044] Furthermore, the reflecting cavity is composed of an outer reflecting cavity 24 and an inner reflecting cavity 25; The guide tube 21 and the first reflective sheet 23 are both disposed on the outer reflective cavity 24. The guide tube 21 is located outside the outer reflective cavity 24, and the first reflective sheet 23 is located inside the outer reflective cavity 24. The cover 22 and the ultrasonic sensor assembly 3 are disposed on the inner reflective cavity 25.

[0045] Furthermore, the inner reflective cavity 25 is a tubular structure, the cover 22 and the ultrasonic sensor assembly 3 are respectively disposed at both ends of the inner reflective cavity 25, the top of the inner reflective cavity 25 is provided with an installation port, and the outer reflective cavity 24 is connected to the inner reflective cavity 25 through the installation port.

[0046] The outer reflective cavity 24 has an arc-shaped structure, and the inner diameter of the arc-shaped structure is adapted to the inner diameter of the inner reflective cavity 25. When the outer reflective cavity 24 is installed on the inner reflective cavity 25, the reflective cavity can form a tubular structure. The outer reflective cavity 24 is provided with a connecting end 241 and a mounting end 242. The connecting end 241 is located on the convex side of the outer reflective cavity 24, and the mounting end 242 is located on the concave side of the outer reflective cavity 24. The connecting end 241 communicates with the mounting end 242. The guide tube 21 is connected to the outer reflective cavity 24 through the connecting end 241. The first reflective sheet 23 is disposed on the mounting end 242. Figure 4 As shown.

[0047] Furthermore, as one embodiment of splitting ultrasonic waves into two paths, the mounting end 242 is provided with a channel communicating with the through hole. The inner diameter of the channel is adapted to the inner diameter of the through hole, so that after the ultrasonic wave is emitted by the ultrasonic sensor assembly 3, it passes through the through hole and enters the channel, contacts the cover 22 and returns. By setting the channel, it can cooperate with the first reflective sheet 23 with the through hole to realize the splitting of ultrasonic waves into two paths for transmission.

[0048] Furthermore, when the first reflector 23 is not provided with a through hole, the channel can be located below the first reflector 23, and the portion of the mounting end 242 without the first reflector 23 can be a plane, with this plane perpendicular to the central axis of the reflecting cavity, to reduce the influence of reflected ultrasonic waves on the ultrasonic waves returning via the cover 22, such as... Figure 6 As shown.

[0049] Furthermore, the ultrasonic sensor assembly 3 consists of an ultrasonic sensor 31, a protective tube 32, a pagoda head 33, and a housing 34; The ultrasonic sensor 31 is disposed inside the housing 34. The ultrasonic sensor 31 is used to emit, receive, and analyze ultrasonic waves to calculate the density and liquid level of the urea solution. The protective tube 32 is connected to the pagoda head 33 on the outer casing 34 to protect the circuit of the ultrasonic sensor 31 from corrosion by urea solution.

[0050] The float assembly 1 consists of a float 11 and a second reflector 12; The float 11 is disposed on the guide tube 21 and is movably connected to the guide tube 21. When the liquid level changes, the float 11 moves along the guide tube 21 as the liquid level changes. The second reflector 12 is disposed at the bottom of the float 11. The second reflector 12 has the function of reflecting ultrasonic waves and is disposed opposite to the first reflector 23. Typically, the central axis of the second reflector 12 is at an angle of 45 degrees with the central axis of the first reflector 23 to ensure that the ultrasonic waves can return to the ultrasonic sensor 31 along the original path.

[0051] The float 11 is provided with a limiting structure, and the guide tube 21 is provided with a mating structure. The limiting structure and the mating structure cooperate to limit the float 11 in the horizontal direction. For example, the limiting structure on the float 11 can be a C-shaped mounting groove, and the guide tube 21 as a whole is set as a C-shaped structure adapted to the mounting groove, so that the guide tube 21 as a whole constitutes a mating structure, thereby limiting the float 11 in the radial direction of the guide tube 21. Figure 2 , Figure 3 and Figure 5 As shown; the limiting structure can also be a limiting slider, and the matching structure is a limiting groove, as long as it can limit the float 11 in the radial direction of the guide tube 21.

[0052] Through the above structural design, the present invention can measure the density of urea solution with a single ultrasonic head. That is, the ultrasonic sensor 31 on the ultrasonic sensor assembly 3 emits high-frequency ultrasonic waves into the urea solution. The ultrasonic waves pass through the through hole on the first reflective sheet 23 on the reflective cavity assembly 2, and pass through the outer reflective cavity 24 (or the channel of the mounting end 242). Then, the ultrasonic waves are reflected by the cap 22. The ultrasonic waves pass through the outer reflective cavity 24 and the first reflective sheet 23 and are reflected back to the ultrasonic sensor 31. After receiving the reflected ultrasonic waves, the ultrasonic sensor 31 calculates the real-time density value by accurately measuring the time difference between the ultrasonic wave emission and reception, combined with a temperature compensation algorithm.

[0053] The present invention can also measure the liquid level of urea solution using a single ultrasonic head. Specifically, the ultrasonic sensor 31 on the ultrasonic sensor assembly 3 emits high-frequency ultrasonic waves into the urea solution. After being reflected by the first reflector 23 on the reflector cavity assembly 2, the ultrasonic waves travel along the guide tube 21 to the float assembly 1. Then, the ultrasonic waves are reflected by the second reflector 12 on the float assembly 1. After traveling along the guide tube 21 to the first reflector 23, the ultrasonic waves are reflected back to the ultrasonic sensor 31. After receiving the reflected ultrasonic waves, the ultrasonic sensor 31 calculates the liquid level height in real time by accurately measuring the time difference between the emission and reception of the ultrasonic waves and combining this with the propagation speed of the ultrasonic waves in the urea medium.

[0054] It should be noted that the ultrasonic sensor 31 mentioned in this application is a collection of one or more existing technologies or commercially available products that can realize ultrasonic emission, reception and analysis, including an ultrasonic generator, receiver, circuit, control center and other components.

[0055] In the foregoing embodiments, we mentioned that when the first reflective sheet 23 has a through hole, the mounting end 242 has a channel communicating with the through hole. This implementation method has the simplest manufacturing process, requiring only drilling. However, in practical applications, this implementation method suffers from the problem of mutual interference between reflected ultrasonic waves. Figure 7 As shown, it is clear that the ultrasonic waves reflected by the first reflector 23 located below the through hole will cross with the ultrasonic waves returning from the channel, thus interfering with the ultrasonic waves used to measure density. Similarly, the ultrasonic waves used to measure liquid level will also be interfered with.

[0056] To eliminate interference between reflected ultrasonic waves, in the aforementioned embodiments, we propose that when the first reflective sheet 23 is not provided with a through hole, the channel can be located below the first reflective sheet 23, and the portion of the mounting end 242 without the first reflective sheet 23 should be a plane, perpendicular to the central axis of the reflecting cavity. This reduces the impact of reflected ultrasonic waves on the ultrasonic waves returning via the cover 22. Figure 6 As shown.

[0057] In this embodiment, although the interference caused by the mutual interference of ultrasonic waves is greatly reduced, because the end face of the mounting end 242 is flat, the ultrasonic waves that were originally divided into two paths become three paths: one path is reflected by the first reflector 23, one path is reflected by the cover 22, and the other path is reflected by the end face of the mounting end 242. In order to eliminate the interference caused by the ultrasonic waves reflected by the mounting end 242, a gap can be reserved between the mounting end 242 and the inner wall of the inner reflection cavity 25. That is, the height of the mounting end 242 is the same as the height of the first reflector 23, and a "channel" is formed between the bottom surface of the mounting end 242 and the inner wall of the inner reflection cavity 25. By eliminating the end face design of the mounting end 242, the ultrasonic wave path is restored to two paths.

[0058] Although the above-described implementation method can reduce the interference caused by the end face reflection of the mounting end 242, it still cannot eliminate the interference of reflected ultrasonic waves from other directions.

[0059] Therefore, based on the implementation where the portion of the mounting end 242 without the first reflective sheet 23 is planar, we have optimized the mounting end 242. In this embodiment, an absorption layer 4 is provided on the plane of the mounting end 242 facing the ultrasonic sensor assembly 3. The absorption layer 4 is made of an ultrasonic wave absorbing material, and a plurality of energy-absorbing grooves are provided on the side of the absorption layer 4 facing the ultrasonic sensor assembly 3. The energy-absorbing grooves extend from the side of the absorption layer 4 close to the ultrasonic sensor assembly 3 to the side away from the ultrasonic sensor assembly 3.

[0060] Furthermore, the energy-absorbing groove is a gradient groove, and the opening area of ​​the energy-absorbing groove is larger than the area of ​​the inner end face of the energy-absorbing groove, so that the energy-absorbing groove can receive ultrasonic waves reflected from all directions.

[0061] Furthermore, the opening and inner end face of the energy-absorbing groove are both hexagonal structures, such as... Figure 8 As shown.

[0062] By setting the absorption layer 4, the ultrasonic waves emitted by the ultrasonic sensor assembly 3 can be divided into three paths: one path is reflected by the first reflector 23, one path is reflected by the cover 22, and one path is absorbed by the absorption layer 4 and does not participate in the reflection. At the same time, the remaining reflected ultrasonic waves in the reflection cavity can be absorbed by the absorption layer 4 after reaching it, thus avoiding the impact of the ultrasonic waves that measure density and liquid level on the measurement.

[0063] As mentioned in the foregoing embodiments, the float 11 and the guide tube 21 are mutually engaged by a limiting structure and a mating structure to limit the float 11 in the horizontal direction. In practical applications, due to the problem of crystallization, the mutually engaging limiting structure and mating structure may become stuck due to crystallization, causing the float 11 to slide poorly or become stuck. To further reduce the impact of crystallization on this application, a crystal removal structure 5 is connected to the top of the float 11 by screws. The crystal removal structure 5 consists of a storage container 51 and several scrapers 52. The top of the storage container 51 has a receiving cavity for holding the crystals removed from the inner wall of the guide tube 21. The scrapers 52 are disposed on the outer wall of the storage container 51. The screws penetrate the bottom of the storage container 51 and connect to the top surface of the float 11. The storage container 51 is movably connected to the screws, so that the screws can be used as the rotation axis of the storage container 51.

[0064] Furthermore, the storage container 51 is a cylindrical structure with an open top. The inner bottom surface of the storage container 51 is provided with a movable hole. The screw passes through the movable hole through the bottom of the storage container 51 and is connected to the top of the float 11.

[0065] Furthermore, the inner bottom of the storage container 51 is provided with a boss 53 extending in the opening direction, and the movable hole is provided on the top of the boss 53. By providing the boss 53, the screw is moved away from the inner bottom surface of the storage container 51, thereby increasing the storage space for crystallization.

[0066] Furthermore, the side wall of the storage container 51 is provided with a plurality of feed holes 54, and a feed hole 54 is provided between two adjacent scrapers 52, so that the crystals scraped off by the scrapers 52 can directly enter the storage container 51 through the feed hole 54.

[0067] Furthermore, the scraper 52 is spirally arranged on the outer wall of the storage container 51 with the central axis of the storage container 51 as the axis of rotation, such as... Figure 11 As shown, the spiral design allows the storage container 51 to rotate when encountering hard-to-scrape crystals, thus allowing the scraper 52 to bypass the hard-to-scrape crystals and avoid jamming.

[0068] Furthermore, there is a gap between the outer wall of the scraper 52 and the inner wall of the guide tube 21, such as... Figure 10 As shown, the crystal removal structure 5 has sufficient room to move during the scraping process to avoid jamming.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A sensor for measuring liquid density and liquid level height using a single ultrasonic head, characterized in that, include: The float assembly (1), the reflective cavity assembly (2), and the ultrasonic sensor assembly (3) are assembled on the reflective cavity assembly (2), the reflective cavity assembly (2) and the ultrasonic sensor assembly (3) are connected, and the ultrasonic sensor assembly (3) is connected to the float assembly (1) through the reflective cavity assembly (2). The float assembly (1) changes with the liquid level and has the function of reflecting ultrasonic waves; The reflective cavity assembly (2) splits the ultrasonic waves into two paths: one path is used to measure the liquid density, and the other path is used to measure the liquid level. The ultrasonic sensor assembly (3) is used to transmit, receive, and analyze ultrasonic waves.

2. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 1, characterized in that, The aforementioned reflective cavity assembly (2) consists of a guide tube (21), a cover (22), a first reflective sheet (23), and a reflective cavity; The guide tube (21) is disposed on the reflective cavity and communicates with the interior of the reflective cavity. The float assembly (1) is assembled on the guide tube (21). The guide tube (21) is used to provide guidance for the float assembly (1). The reflective cavity is provided with an exhaust hole for discharging air bubbles; The ultrasonic sensor assembly (3) is disposed at one end of the reflecting cavity, and the cover (22) is disposed at the end of the reflecting cavity away from the ultrasonic sensor assembly (3). The first reflector (23) is disposed in the reflective cavity and located between the ultrasonic sensor assembly (3) and the cover (22); Both the cover (22) and the first reflective sheet (23) have the function of reflecting ultrasonic waves; The first reflector (23) divides the ultrasonic waves into two paths. One ultrasonic wave contacts the cover (22) to measure the liquid density, and the other ultrasonic wave contacts the first reflector (23) to measure the liquid level.

3. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 2, characterized in that, A through hole is provided on the first reflective sheet (23).

4. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 2, characterized in that, The reflective cavity is a tubular structure. The cover (22) and the ultrasonic sensor assembly (3) are located at the two ends of the reflective cavity, respectively. The guide tube (21) is arranged vertically on the side wall of the reflective cavity, and the central axis of the guide tube (21) is perpendicular to the central axis of the reflective cavity.

5. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 4, characterized in that, The reflecting cavity is composed of an outer reflecting cavity (24) and an inner reflecting cavity (25); The guide tube (21) and the first reflective sheet (23) are both disposed on the outer reflective cavity (24). The guide tube (21) is located outside the outer reflective cavity (24), and the first reflective sheet (23) is located inside the outer reflective cavity (24). The cover (22) and the ultrasonic sensor assembly (3) are disposed on the inner reflective cavity (25).

6. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 5, characterized in that, The inner reflective cavity (25) is a tubular structure. The cover (22) and the ultrasonic sensor assembly (3) are respectively disposed at both ends of the inner reflective cavity (25). The top of the inner reflective cavity (25) is provided with an installation port. The outer reflective cavity (24) is connected to the inner reflective cavity (25) through the installation port.

7. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 6, characterized in that, The outer reflective cavity (24) has an arc-shaped structure, and the inner diameter of the arc-shaped structure is adapted to the inner diameter of the inner reflective cavity (25). The outer reflective cavity (24) is provided with a connecting end (241) and a mounting end (242). The connecting end (241) is located on the convex side of the outer reflective cavity (24), and the mounting end (242) is located on the concave side of the outer reflective cavity (24). The connecting end (241) is connected to the mounting end (242). The guide tube (21) is connected to the outer reflective cavity (24) through the connecting end (241). The first reflective sheet (23) is disposed on the mounting end (242).

8. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 1, characterized in that, The ultrasonic sensor assembly (3) consists of an ultrasonic sensor (31), a protective tube (32), a pagoda head (33), and a housing (34); The ultrasonic sensor (31) is disposed inside the housing (34). The ultrasonic sensor (31) is used to emit, receive and analyze ultrasonic waves to calculate the density and level of the urea solution. The protective tube (32) is connected to the pagoda head (33) on the outer shell (34) to protect the circuit of the ultrasonic sensor (31) from corrosion by urea solution.

9. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 2, characterized in that, The float assembly (1) consists of a float (11) and a second reflector (12); The float (11) is disposed on the guide tube (21) and is movably connected to the guide tube (21). When the liquid level changes, the float (11) moves along the guide tube (21) as the liquid level changes. The second reflector (12) is disposed at the bottom of the float (11) and is disposed opposite to the first reflector (23). The second reflector (12) has the function of reflecting ultrasonic waves.

10. The sensor for measuring liquid density and liquid level height using a single ultrasonic head according to claim 9, characterized in that, The float (11) is provided with a limiting structure, and the guide tube (21) is provided with a matching structure. The limiting structure and the matching structure are matched to limit the float (11) in the horizontal direction.

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