A sensor for measuring liquid density and liquid level height with a single ultrasonic head

Abstract

The application discloses a kind of single ultrasonic head measuring liquid density and liquid level sensor, it is related to the technical field of liquid level measurement, including: float assembly, reflection cavity assembly and ultrasonic sensor assembly;Float assembly is assembled on reflection cavity assembly, reflection cavity assembly and ultrasonic sensor assembly are connected, and ultrasonic sensor assembly is connected with float assembly by reflection cavity assembly.The application transmits and receives high-frequency ultrasonic wave by single point, synchronously analyzes sound velocity (density) and back ultrasonic wave time difference (liquid level), and calculates the density and liquid level of urea solution, avoids mechanical interference and data fragmentation problem, reduces the cost of opening and cable;High-precision temperature compensation module is shared to directly eliminate the compensation deviation of split system, maintenance only needs single-point anti-crystallization treatment;Combined with cross-validation algorithm (density liquid level logic mutual inspection), while improving data reliability, reduce operation and maintenance cost, especially suitable for space limited, strong corrosion urea solution detection scene.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid level measurement, and more particularly to a sensor for measuring liquid density and liquid level height with a single ultrasonic head. BACKGROUND

[0002] To meet the requirements of the national six emission standards, diesel engines generally use SCR (Selective Catalytic Reduction) technology to treat exhaust gas. In this system, urea solution acts as a reducing agent and chemically reacts with nitrogen oxides (including NO and NO2) in the exhaust gas, ultimately generating harmless nitrogen and water, thereby effectively reducing pollutant emissions. To ensure the purification effect of the SCR system, the quality concentration of the urea solution must be strictly controlled near the standard value of 32.5%. When the concentration is detected to deviate from the allowed range, the system should timely issue a warning signal. In addition, it is also necessary to monitor the solution inventory in the urea tank in real time, and when the liquid level falls below the preset warning line, the system should trigger the alarm function to remind the operator to replenish the urea solution in time.

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

[0004] 1. Ultrasonic method for detecting the density of urea solution (i.e. using the physical relationship between the propagation speed of ultrasonic waves in urea solution and density);

[0005] The change of urea concentration will change the propagation speed of ultrasonic waves in the solution, the higher the concentration, the faster the sound speed. The sensor accurately measures the time difference between the emission and reception of ultrasonic waves, and calculates the real-time density value combined with the temperature compensation algorithm. The defect of this scheme is that the measurement accuracy is easily affected by the solution flow rate, bubbles, suspended solids and changes in the internal acoustic properties of the liquid (such as viscosity); the initial equipment cost is relatively high; in extreme working conditions (such as severe shaking or presence of a large amount of foam), the signal may be unstable or attenuated, resulting in measurement failure; in addition, more professional knowledge is usually required for installation and debugging to ensure the ultrasonic wave path and signal quality.

[0006] 2. Refractive index method for detecting the density of urea solution (i.e. based on the change of refraction angle when light passes through urea solution);

[0007] The concentration of urea is linearly related to the refractive index, and the sensor converts the density value by emitting infrared light and detecting the refraction angle. The defect of this scheme is that it requires high purity of the solution, and bubbles, impurities or crystals will significantly interfere with the measurement accuracy; at the same time, it relies on a temperature compensation mechanism (the refractive index of urea solution is easily affected by temperature), and if the temperature control is not accurate, the result will be deviated; in addition, this method cannot be applied to non-transparent or strongly corrosive urea solution variants, and the application range has limitations.

[0008] The liquid level of the urea solution is usually measured by a capacitive liquid level sensor, an ultrasonic liquid level sensor, or a magnetostrictive liquid level meter.

[0009] 1. The capacitive liquid level sensor measures the liquid level of the urea solution (i.e., the capacitive liquid level sensor converts the liquid level height into a change in capacitance value by detecting the change in dielectric constant between the electrodes caused by the change in the liquid level of the urea solution, and then inversely calculates the liquid level data in real time);

[0010] The disadvantages of this scheme are that it is easily disturbed by the urea crystalline layer on the electrode surface, the crystallization can cause the capacitance value to drift, resulting in continuous measurement deviation; at the same time, changes in the conductivity of the urea solution (such as impurities penetrating) or temperature fluctuations can significantly affect the stability of the dielectric constant, requiring additional compensation algorithms; in addition, the metal electrodes of the sensor are easily corroded during long-term use, and high-viscosity solutions may produce adhesion errors, requiring frequent maintenance and calibration to ensure accuracy.

[0011] 2. The ultrasonic liquid level sensor measures the liquid level of the urea solution (i.e., by emitting high-frequency ultrasonic waves to the urea solution and accurately measuring the propagation time difference of the ultrasonic waves from emission to reflection back to the receiving probe, combined with the propagation speed of ultrasonic waves in the urea medium, the liquid level height is calculated in real time);

[0012] The disadvantages of this scheme are that foam or crystalline layer can scatter or absorb ultrasonic waves, resulting in loss or distortion of the reflected ultrasonic signal, changes in urea density at high temperatures affect the accuracy of sound speed and require real-time temperature compensation, strong vibration or complex tank structure can easily produce interference reflected ultrasonic waves, and urea crystallization in low-temperature environment may cover the probe, requiring frequent maintenance and relying on high-precision signal processing algorithms to ensure reliability.

[0013] 3. The magnetostrictive liquid level meter measures the liquid level of the urea solution (i.e., the magnetic float moves with the liquid level of the urea solution to disturb the magnetic field of the ultrasonic wave guide wire, triggering the time difference detection of the current pulse and the torsional ultrasonic wave, and accurately converting the liquid level height);

[0014] The disadvantages of this scheme are that the magnetic float is easily stuck by urea crystallization or high-viscosity impurities adhesion, causing measurement failure; temperature fluctuations affect the propagation speed of the torsional ultrasonic wave in the ultrasonic wave guide wire and require dynamic compensation; installation must be strictly vertical, if the inclination exceeds 3°, significant error will occur, and strong electromagnetic environment will interfere with the timing of the pulse signal; long-term contact with the urea solution may corrode the metal sheath of the ultrasonic wave guide wire, requiring frequent cleaning and maintenance and relying on redundant design to ensure reliability.

[0015] It can be seen from the above that the existing method for detecting the density and liquid level of urea solution generally uses two ultrasonic sensors to measure the density and liquid level of urea solution respectively, or uses an infrared light sensor to measure the density of urea solution and an ultrasonic sensor to measure the liquid level of urea solution. The defect of this scheme is that the double-probe separate measurement scheme (such as ultrasonic + ultrasonic or infrared light + ultrasonic combination) needs to open two independent installation holes in the urea tank, which greatly increases the risk of seal failure and medium leakage. The density probe needs to be immersed in the solution for measurement (the infrared light method requires a clean light window without crystallization, and the ultrasonic immersion type needs to prevent bubble interference), while the liquid level probe is sensitive to the installation position and liquid surface state, and the independent calibration of the two systems leads to different temperature compensation (the measurement error of density and liquid level is higher under the temperature gradient of urea solution). More seriously, both probes need to be frequently maintained in a crystalline environment, which has higher maintenance cost and greater shutdown risk. Therefore, how to use one probe to realize the detection of density and liquid level double parameters, simplify the system structure and reduce the installation and maintenance cost is the technical problem to be solved by the present application. SUMMARY

[0016] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiment section. The summary section of the present application does not mean to attempt to limit the key features and necessary technical features of the claimed technical solution, nor to attempt to determine the protection scope of the claimed technical solution.

[0017] To at least partially solve the above problems, the present application provides a single ultrasonic head sensor for measuring liquid density and liquid level height, comprising: a float assembly, a reflection cavity assembly and an ultrasonic sensor assembly; the float assembly is assembled on the reflection cavity assembly, the reflection cavity assembly and the ultrasonic sensor assembly are connected, and the ultrasonic sensor assembly is connected with the float assembly through the reflection cavity assembly;

[0018] The float assembly changes with the liquid level height and has the function of reflecting ultrasonic waves;

[0019] The reflection cavity assembly divides the ultrasonic waves into two paths, one path of ultrasonic waves is used to measure the liquid density, and the other path of ultrasonic waves is used to measure the liquid level height;

[0020] The ultrasonic sensor assembly is used for emitting, receiving and analyzing ultrasonic waves.

[0021] Preferably, the reflection cavity assembly is composed of a guide pipe, a cover, a first reflection sheet and a reflection cavity;

[0022] The guide pipe is arranged on the reflection cavity and communicates with the inside of the reflection cavity, the float assembly is assembled on the guide pipe, and the guide pipe is used to provide a guiding effect for the float assembly;

[0023] The reflection cavity is provided with an exhaust hole for exhausting air bubbles;

[0024] The ultrasonic sensor assembly is arranged at one end of the reflection cavity, and the cover is arranged at the other end of the reflection cavity away from the ultrasonic sensor assembly,

[0025] The first reflection sheet is arranged in the reflection cavity and located between the ultrasonic sensor assembly and the cover;

[0026] The cover and the first reflection sheet both have the function of reflecting ultrasonic waves;

[0027] The first reflection sheet divides the ultrasonic waves into two paths, one path of the ultrasonic waves contacts the cover to measure the liquid density, and the other path of the ultrasonic waves contacts the first reflection sheet to measure the liquid level.

[0028] Preferably, the first reflection sheet is provided with a through hole.

[0029] Preferably, the reflection cavity is a tubular structure, the cover and the ultrasonic sensor assembly are respectively arranged at two ends of the reflection cavity, the guide pipe is arranged on the side wall of the reflection cavity in the vertical direction, and the central axis of the guide pipe is perpendicular to the central axis of the reflection cavity.

[0030] Preferably, the reflection cavity is composed of an outer reflection cavity and an inner reflection cavity;

[0031] The guide pipe and the first reflection sheet are both arranged on the outer reflection cavity, the guide pipe is located outside the outer reflection cavity, and the first reflection sheet is located inside the outer reflection cavity;

[0032] The cover and the ultrasonic sensor assembly are arranged on the inner reflection cavity.

[0033] Preferably, the inner reflection cavity is a tubular structure, the cover and the ultrasonic sensor assembly are respectively arranged at two ends of the inner reflection cavity, the top of the inner reflection cavity is provided with a mounting port, and the outer reflection cavity is connected with the inner reflection cavity through the mounting port.

[0034] Preferably, the outer reflection cavity is an arc-shaped structure, the inner diameter of the arc-shaped structure is adapted to the inner diameter of the inner reflection cavity, the outer reflection cavity is provided with a connecting end and a mounting end, the connecting end is located on the side of the outer reflection cavity protruding outward, the mounting end is located on the side of the outer reflection cavity recessed inward, the connecting end and the mounting end are in communication, the guide pipe is connected with the outer reflection cavity through the connecting end, and the first reflection sheet is arranged on the mounting end.

[0035] Preferably, the ultrasonic sensor assembly is composed of an ultrasonic sensor, a wire protection tube, a cone head and a shell.

[0036] The ultrasonic sensor is arranged in the shell, and is used for emitting, receiving and analyzing ultrasonic waves, calculating the density and liquid level of the urea solution.

[0037] The protective tube is connected with the tower head on the shell, and is used for protecting the line of the ultrasonic sensor from corrosion of the urea solution.

[0038] Preferably, the float assembly is composed of a float and a second reflecting sheet.

[0039] The float is arranged on the guide pipe and movably connected with the guide pipe, and when the liquid level changes, the float moves along the guide pipe with the change of the liquid level.

[0040] The second reflecting sheet is arranged at the bottom of the float and oppositely arranged with the first reflecting sheet, and the second reflecting sheet has the function of reflecting ultrasonic waves.

[0041] Preferably, a limiting structure is arranged on the float, and a matching structure is arranged on the guide pipe, and the limiting structure and the matching structure are matched, and are used for limiting the float in the horizontal direction.

[0042] Compared with the prior art, the present application at least has the following beneficial effects:

[0043] The present application adopts a single probe measurement scheme, transmits and receives high-frequency ultrasonic waves through a single point, synchronously analyzes the sound velocity (density) and the back ultrasonic wave time difference (liquid level), and calculates the density and liquid level of the urea solution, avoids the problems of mechanical interference and data fragmentation, reduces the opening and cable costs; shares a high-precision temperature compensation module to directly eliminate the compensation deviation of the split system, and only needs single-point anti-crystallization treatment for maintenance; combined with the cross-validation algorithm (density and liquid level logic mutual verification), the data reliability is improved while the operation and maintenance cost is reduced, and it is especially suitable for urea solution detection scenes with limited space and strong corrosion.

[0044] The single ultrasonic head liquid density and liquid level height measuring sensor of the present application, other advantages, objects and features of the present application will be partially embodied through the following description, and some will be understood by those skilled in the art through research and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0045] The accompanying drawings are used to provide further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, for explaining the present application, and do not constitute a limitation on the present application. In the drawings:

[0046] Figure 1 It is a schematic view of the single ultrasonic head liquid density and liquid level height measuring sensor of the present application.

[0047] Figure 2 It is a schematic view of the single ultrasonic head liquid density and liquid level height measuring sensor of the present application.Figure 1 An exploded view of the application.

[0048] Figure 3 An exploded view of the application. Figure 2 An exploded view of the application.

[0049] Figure 4 A cross-sectional view of the sensor for measuring liquid density and liquid level height with a single ultrasonic head according to the application.

[0050] Figure 5 A cross-sectional view of the sensor for measuring liquid density and liquid level height with a single ultrasonic head according to the application.

[0051] Figure 6 A cross-sectional view of another embodiment of the application.

[0052] Figure 7 A schematic view of ultrasonic wave interference.

[0053] Figure 8 A schematic view of the absorption layer.

[0054] Figure 9 A schematic view of the location of the crystallization removal structure.

[0055] Figure 10 A schematic view of the absorption layer. Figure 9 A schematic view of the crystallization removal structure.

[0056] Figure 11 A schematic view of the crystallization removal structure.

[0057] 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 wire protection tube, 33 spool head, 34 housing, 4 absorption layer, 5 crystallization removal structure, 51 storage container, 52 scraper, 53 boss, 54 feed hole. DETAILED DESCRIPTION

[0058] The application will be further described below in conjunction with the drawings and examples, so that those skilled in the art can implement the application according to the description.

[0059] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0060] As Figures 1-11As shown, the present application provides a single ultrasonic head sensor for measuring liquid density and liquid level, comprising: a float assembly 1, a reflection cavity assembly 2 and an ultrasonic sensor assembly 3; the float assembly 1 is assembled on the reflection cavity assembly 2, the reflection cavity assembly 2 and the ultrasonic sensor assembly 3 are connected, and the ultrasonic sensor assembly 3 is connected with the float assembly 1 through the reflection cavity assembly 2;

[0061] The float assembly 1 can change with the change of the liquid level and has the function of reflecting ultrasonic waves;

[0062] The reflection cavity assembly 2 can divide the ultrasonic waves emitted by the ultrasonic sensor assembly 3 into two paths, one path of the ultrasonic waves is used for measuring the liquid density, the ultrasonic sensor assembly 3 calculates the real-time density value by accurately measuring the time difference between the emission and reception of the ultrasonic waves and combining the temperature compensation algorithm; the other path of the ultrasonic waves is reflected to the float assembly 1 through the reflection cavity assembly 2, and then reflected back to the reflection cavity assembly 2 through the float assembly 1, and finally returned to the ultrasonic sensor assembly 3, which is used for measuring the liquid level, the ultrasonic sensor assembly 3 calculates the liquid level in real time by accurately measuring the time difference between the emission and reception of the ultrasonic waves and combining the propagation speed of the ultrasonic waves in the urea medium;

[0063] The ultrasonic sensor assembly 3 is used for emitting, receiving and analyzing ultrasonic waves.

[0064] The existing method for detecting the density and liquid level of urea solution usually uses two ultrasonic sensors to measure the density and liquid level of urea solution respectively, or uses an infrared light sensor to measure the density of urea solution and then uses an ultrasonic sensor to measure the liquid level of urea solution. The present application realizes the two-in-one measurement of the density and liquid level of urea solution by using an ultrasonic sensor, and the core advantage is that the single ultrasonic probe realizes non-contact double-parameter detection simultaneously: the liquid level is calculated by analyzing the time difference of the return ultrasonic waves, and the density value is calculated by using the strong correlation between the sound speed and the density (the change of the density of urea solution significantly changes the sound speed) and combining the temperature compensation, thereby greatly simplifying the system structure, reducing the installation and maintenance cost, avoiding the crystallization pollution risk caused by medium contact, and improving the reliability and real-time performance of industrial deployment.

[0065] In addition, the present application adopts a single-probe measurement scheme, transmits and receives high-frequency ultrasonic waves at a single point, synchronously analyzes the sound speed (density) and the time difference of the return ultrasonic waves (liquid level), and calculates the density and liquid level of urea solution, thereby avoiding the mechanical interference and data fragmentation problem, reducing the opening and cable cost; sharing the high-precision temperature compensation module directly eliminates the compensation deviation of the split system, and maintenance only needs single-point anti-crystallization treatment; combining the cross-validation algorithm (density and liquid level logic mutual verification), the data reliability is improved while the operation and maintenance cost is reduced, and it is especially suitable for urea solution detection scenes with limited space and strong corrosion.

[0066] The reflection cavity assembly 2 is composed of a guide pipe 21, a cover 22, a first reflection sheet 23 and a reflection cavity;

[0067] The guide pipe 21 is arranged on the reflection cavity and communicates with the inside of the reflection cavity, the float assembly 1 is assembled on the guide pipe 21, and the guide pipe 21 is used for providing a guide function for the float assembly 1, so that the float assembly 1 can move along with the liquid surface on the guide pipe 21 when the liquid level changes;

[0068] An exhaust hole is arranged on the reflection cavity and used for exhausting bubbles;

[0069] The ultrasonic sensor assembly 3 is arranged at one end of the reflection cavity, and the cover 22 is arranged at the end of the reflection cavity away from the ultrasonic sensor assembly 3,

[0070] The first reflection sheet 23 is arranged in the reflection cavity and located between the ultrasonic sensor assembly 3 and the cover 22, and is usually arranged in an inclined manner, preferably at an angle of 45 degrees, so as to reflect ultrasonic waves to the float assembly 1 and the ultrasonic sensor assembly 3;

[0071] Both the cover 22 and the first reflection sheet 23 have the function of reflecting ultrasonic waves;

[0072] The first reflection sheet 23 divides the ultrasonic waves into two paths, one path of the ultrasonic waves does not contact the first reflection sheet 23, directly contacts the cover 22 and is reflected back to the ultrasonic sensor assembly 3 through the cover 22, and is used for measuring the liquid density; the other path of the ultrasonic waves contacts the first reflection sheet 23, is reflected to the float assembly 1, is reflected back to the first reflection sheet 23 by the float assembly 1, and is finally reflected back to the ultrasonic sensor assembly 3 through the first reflection sheet 23, and is used for measuring the liquid level.

[0073] As one of the embodiments of dividing the ultrasonic waves into two paths, a through hole is arranged on the first reflection sheet 23, a central axis of the through hole is located at the center of the cover 22 and is perpendicular to the cover 22, as shown in Figure 4 and Figure 5 Thus, the ultrasonic waves can directly act on the center of the cover 22 after passing through the first reflection sheet 23 through the through hole and return along the original path.

[0074] Further, the reflection cavity is a tubular structure, the cover 22 and the ultrasonic sensor assembly 3 are respectively located at two ends of the reflection cavity, as shown in Figure 4 The guide pipe 21 is arranged on the side wall of the reflection cavity in a vertical direction, and a central axis of the guide pipe 21 is perpendicular to a central axis of the reflection cavity.

[0075] Further, the reflection cavity is composed of an outer reflection cavity 24 and an inner reflection cavity 25;

[0076] The guide tube 21 and the first reflecting sheet 23 are arranged on the outer reflecting cavity 24, the guide tube 21 is located outside the outer reflecting cavity 24, and the first reflecting sheet 23 is located inside the outer reflecting cavity 24.

[0077] The cover 22 and the ultrasonic sensor assembly 3 are arranged on the inner reflecting cavity 25.

[0078] Further, the inner reflecting cavity 25 is a tubular structure, the cover 22 and the ultrasonic sensor assembly 3 are arranged at two ends of the inner reflecting cavity 25 respectively, and the top of the inner reflecting cavity 25 is provided with a mounting port, and the outer reflecting cavity 24 is connected with the inner reflecting cavity 25 through the mounting port.

[0079] The outer reflecting cavity 24 is an arc structure, and the inner diameter of the arc structure is adapted to the inner diameter of the inner reflecting cavity 25, when the outer reflecting cavity 24 is mounted on the inner reflecting cavity 25, the reflecting cavity can form a tubular structure, the outer reflecting cavity 24 is provided with a connecting end 241 and a mounting end 242, the connecting end 241 is located on the side of the outer reflecting cavity 24 protruding outward, the mounting end 242 is located on the side of the outer reflecting cavity 24 recessing inward, and the connecting end 241 is in communication with the mounting end 242, the guide tube 21 is connected with the outer reflecting cavity 24 through the connecting end 241, and the first reflecting sheet 23 is arranged on the mounting end 242, as shown in Figure 4 .

[0080] Further, as one of the embodiments of dividing the ultrasonic wave into two paths, the mounting end 242 is provided with a channel in communication with the through hole, and the inner diameter of the channel is adapted to the inner diameter of the through hole, so that the ultrasonic wave emitted by the ultrasonic sensor assembly 3 passes through the through hole into the channel, returns after contacting the cover 22, and by arranging the channel, the first reflecting sheet 23 provided with the through hole can be matched to realize the division of the ultrasonic wave into two paths for transmission.

[0081] Further, when the first reflecting sheet 23 is not provided with the through hole, the channel can be arranged below the first reflecting sheet 23, and the part of the mounting end 242 not provided with the first reflecting sheet 23 is a plane, and the plane is perpendicular to the central axis of the reflecting cavity, so as to reduce the influence of the reflected ultrasonic wave on the ultrasonic wave returned through the cover 22, as shown in Figure 6 .

[0082] Further, the ultrasonic sensor assembly 3 is composed of an ultrasonic sensor 31, a wire protection tube 32, a pagoda head 33 and a shell 34.

[0083] The ultrasonic sensor 31 is arranged in the shell 34, and the ultrasonic sensor 31 is used for emitting, receiving and analyzing ultrasonic waves, calculating the density and liquid level of urea solution.

[0084] The protective tube 32 is connected with the tower head 33 on the shell 34, and is used for protecting the line of the ultrasonic sensor 31 from corrosion of the urea solution.

[0085] The float assembly 1 is composed of a float 11 and a second reflecting sheet 12.

[0086] The float 11 is arranged on the guide pipe 21 and movably connected with the guide pipe 21, and when the liquid level changes, the float 11 moves along the guide pipe 21 with the change of the liquid level.

[0087] The second reflecting sheet 12 is arranged at the bottom of the float 11, and has the function of reflecting ultrasonic waves, and is oppositely arranged with the first reflecting sheet 23, and the included angle between the central axis of the second reflecting sheet 12 and the central axis of the first reflecting sheet 23 is 45 degrees, so as to ensure that the ultrasonic waves can return to the ultrasonic sensor 31 in the original path.

[0088] The float 11 is provided with a limiting structure, and the guide pipe 21 is provided with a matching structure, and the limiting structure and the matching structure are matched, and are used for limiting 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 pipe 21 is integrally arranged as a C-shaped structure matched with the mounting groove, so that the guide pipe 21 integrally forms the matching structure, thereby limiting the float 11 in the radial direction of the guide pipe 21, as shown in Figure 2 、 Figure 3 and Figure 5 The limiting structure can also be a limiting sliding block, and the matching structure is a limiting sliding groove, as long as the float 11 can be limited in the radial direction of the guide pipe 21.

[0089] Through the above structure, the density of the urea solution can be measured by a single ultrasonic head, that is, the ultrasonic sensor 31 on the ultrasonic sensor assembly 3 emits high-frequency ultrasonic waves to the urea solution, the ultrasonic waves pass through the through hole on the first reflecting sheet 23 of the reflecting cavity assembly 2, pass through the outer reflecting cavity 24 (or the channel of the mounting end 242), and then reflect the ultrasonic waves through the cover 22, the ultrasonic waves pass through the outer reflecting cavity 24 and the first reflecting sheet 23 and are reflected back to the ultrasonic sensor 31, after receiving the reflected ultrasonic waves, the ultrasonic sensor 31 measures the time difference between the emission and reception of the ultrasonic waves, and calculates the real-time density value by combining the temperature compensation algorithm.

[0090] The application can also measure the liquid level of the urea solution by the single ultrasonic head, that is, the ultrasonic sensor 31 on the ultrasonic sensor assembly 3 emits high-frequency ultrasonic waves to the urea solution, the ultrasonic waves are reflected by the first reflecting sheet 23 on the reflecting cavity assembly 2, and then reach the float assembly 1 along the guide pipe 21, and then the second reflecting sheet 12 on the float assembly 1 reflects the ultrasonic waves, and then the ultrasonic waves reach the first reflecting sheet 23 along the guide pipe 21, and then 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 the propagation speed of the ultrasonic waves in the urea medium.

[0091] It should be noted that the ultrasonic sensor 31 mentioned in the present application is a collection of one or more existing technologies or commercially available products that can realize ultrasonic emission, reception and analysis, including ultrasonic generators, receivers, lines, control centers, etc.

[0092] In the foregoing embodiment, we mentioned that when the first reflecting sheet 23 is provided with a through hole, the mounting end 242 is provided with a channel communicating with the through hole. The production process of this embodiment is the simplest, which only needs to punch a hole. However, when this embodiment is applied in practice, the reflected ultrasonic waves interfere with each other, as shown in Figure 7 It can be seen that the ultrasonic waves reflected by the first reflecting sheet 23 below the through hole will cross the ultrasonic waves returned by the channel, and further interfere with the ultrasonic waves for measuring the density, and the ultrasonic waves for measuring the liquid level will also be interfered.

[0093] To eliminate the interference between the reflected ultrasonic waves, in the foregoing embodiment, we propose that when the first reflecting sheet 23 is not provided with a through hole, the channel can be arranged below the first reflecting sheet 23, and the part of the mounting end 242 without the first reflecting sheet 23 is a plane, and the plane is perpendicular to the central axis of the reflecting cavity, so as to reduce the influence of the reflected ultrasonic waves on the ultrasonic waves returned by the cover 22, as shown in Figure 6 .

[0094] In this embodiment, although the interference caused by the mutual interference of the ultrasonic waves is greatly weakened, because the end face of the mounting end 242 is a plane, the originally two-way ultrasonic waves become three-way, one way is reflected by the first reflecting sheet 23, one way is reflected by the cover 22, and one way is reflected by the end face of the mounting end 242. In order to eliminate the interference caused by the reflected ultrasonic waves of the mounting end 242, a gap can be reserved between the mounting end 242 and the inner wall of the inner reflecting cavity 25, that is, the height of the mounting end 242 is consistent with the height of the first reflecting sheet 23, and a “channel” is formed between the bottom surface of the mounting end 242 and the inner wall of the inner reflecting cavity 25. By canceling the end face design of the mounting end 242, the path of the ultrasonic waves is restored to two ways.

[0095] Although the above-mentioned embodiments can reduce the interference caused by the end face reflection of the mounting end 242, the interference of the reflected ultrasonic waves from other directions cannot be eliminated.

[0096] Therefore, based on the embodiment that the part of the mounting end 242 where the first reflecting sheet 23 is not arranged is flat, the mounting end 242 is optimized. In the present embodiment, a plurality of energy absorbing grooves are arranged on the flat surface of the side of the mounting end 242 facing the ultrasonic sensor assembly 3, and the energy absorbing grooves extend from the side of the energy absorbing layer 4 close to the ultrasonic sensor assembly 3 to the side away from the ultrasonic sensor assembly 3.

[0097] Further, the energy absorbing grooves are tapered grooves, and the opening area of the energy absorbing grooves is greater than the area of the inner end surface of the energy absorbing grooves, so that the energy absorbing grooves can receive the ultrasonic waves reflected from various directions.

[0098] Further, the opening and the inner end surface of the energy absorbing grooves are hexagonal structures, as shown in Figure 8 .

[0099] By arranging the energy absorbing 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 reflecting sheet 23, one path is reflected by the cover 22, and one path is absorbed by the energy absorbing layer 4 and does not participate in reflection; at the same time, the remaining reflected ultrasonic waves in the reflection cavity can be absorbed by the energy absorbing layer 4 after reaching the energy absorbing layer 4, so as to avoid the influence of the secondary reflection on the ultrasonic waves for measuring the density and the liquid level.

[0100] In the foregoing embodiments, it is mentioned that the float 11 and the guide pipe 21 are limited in the horizontal direction by the limiting structure and the cooperating structure. In actual application, because of the crystallization problem, the limiting structure and the cooperating structure may be stuck together due to the crystallization problem, resulting in the situation that the float 11 is not smooth or stuck. In order to further reduce the influence of crystallization on the present application, a crystallization removing structure 5 is connected to the top of the float 11 by a screw. The crystallization removing structure 5 is composed of a storage container 51 and a plurality of scrapers 52. The top of the storage container 51 has a containing cavity for containing the crystallization removed from the inner wall of the guide pipe 21. The scrapers 52 are arranged on the outer wall of the storage container 51. The screw is connected to the top surface of the float 11 by penetrating the bottom of the storage container 51. The storage container 51 is movably connected to the screw, so that the screw can be used as the rotating shaft of the storage container 51.

[0101] Further, the storage container 51 is a top-opened cylindrical structure, and the inner bottom surface of the storage container 51 is provided with a movable hole through which a screw penetrates the bottom of the storage container 51 and is connected with the top of the float 11.

[0102] Further, the inner bottom of the storage container 51 is provided with a boss 53 extending in the opening direction, and the movable hole is arranged on the top of the boss 53. By arranging the boss 53, the screw is away from the inner bottom surface of the storage container 51, thereby increasing the storage space of the crystals.

[0103] Further, the sidewall of the storage container 51 is provided with a plurality of feeding holes 54, and one feeding hole 54 is arranged between two adjacent scrapers 52, so that the crystals scraped by the scraper 52 can directly enter the storage container 51 through the feeding hole 54.

[0104] Further, the scraper 52 is arranged in a spiral shape on the outer wall of the storage container 51 with the central axis of the storage container 51 as the rotation axis, as shown in the figure. Figure 11 By arranging in a spiral shape, when the crystals are difficult to be scraped, the storage container 51 can be driven to rotate, so that the scraper 52 bypasses the crystals difficult to be scraped, thereby avoiding being stuck.

[0105] Further, the outer sidewall of the scraper 52 and the inner sidewall of the guide pipe 21 have a gap, as shown in the figure. Figure 10 Therefore, when the crystals are scraped, the crystal removing structure 5 has sufficient movement space, thereby avoiding being stuck.

[0106] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0107] In this application, unless otherwise clearly indicated and limited, the terms "mounting", "connection", "connecting", "fixed", and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection or communication with each other; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0108] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A sensor for measuring the density and level of a liquid with a single ultrasonic head, characterized by, The utility model relates to a liquid level sensor, which comprises a float assembly (1), a reflection cavity assembly (2) and an ultrasonic sensor assembly (3); the float assembly (1) is assembled on the reflection cavity assembly (2), the reflection cavity assembly (2) is connected with the ultrasonic sensor assembly (3), and the ultrasonic sensor assembly (3) is connected with the float assembly (1) through the reflection cavity assembly (2); The float assembly (1) changes with the liquid level height and has the function of reflecting ultrasonic waves; The reflection cavity assembly (2) divides ultrasonic waves into two paths, one path of ultrasonic waves is used to measure the liquid density, and the other path of ultrasonic waves is used to measure the liquid level height; The ultrasonic sensor assembly (3) is used to emit, receive and analyze ultrasonic waves; The reflection cavity assembly (2) is composed of a guide pipe (21), a cover (22), a first reflecting sheet (23) and a reflection cavity; The guide pipe (21) is arranged on the reflection cavity and communicates with the inside of the reflection cavity, the float assembly (1) is assembled on the guide pipe (21), and the guide pipe (21) is used to provide a guide function for the float assembly (1); An exhaust hole is arranged on the reflection cavity and used to exhaust air bubbles; The ultrasonic sensor assembly (3) is arranged at one end of the reflection cavity, the cover (22) is arranged at the end of the reflection cavity away from the ultrasonic sensor assembly (3), The first reflecting sheet (23) is arranged in the reflection cavity and located between the ultrasonic sensor assembly (3) and the cover (22); The cover (22) and the first reflecting sheet (23) both have the function of reflecting ultrasonic waves; The first reflecting sheet (23) divides ultrasonic waves into two paths, one path of ultrasonic waves contacts the cover (22) and is used to measure the liquid density, and the other path of ultrasonic waves contacts the first reflecting sheet (23) and is used to measure the liquid level height. A through hole is arranged on the first reflecting sheet (23).

2. The sensor for measuring density and level of liquid with single ultrasonic head according to claim 1, characterized in that, The reflection cavity is a tubular structure, the cover (22) and the ultrasonic sensor assembly (3) are respectively arranged at two ends of the reflection cavity, the guide pipe (21) is arranged on the side wall of the reflection cavity in the vertical direction, and the central axis of the guide pipe (21) is perpendicular to the central axis of the reflection cavity.

3. The sensor for measuring density and level of liquid with single ultrasonic head according to claim 1, wherein, The reflection cavity is composed of an outer reflection cavity (24) and an inner reflection cavity (25); 4. The sensor for measuring density and level of liquid with a single ultrasonic head according to claim 3, wherein The guide pipe (21) and the first reflecting sheet (23) are both arranged on the outer reflection cavity (24), the guide pipe (21) is located outside the outer reflection cavity (24), and the first reflecting sheet (23) is located inside the outer reflection cavity (24); The cover (22) and the ultrasonic sensor assembly (3) are arranged on the inner reflection cavity (25). The inner reflection cavity (25) is a tubular structure, the cover (22) and the ultrasonic sensor assembly (3) are respectively arranged at two ends of the inner reflection cavity (25), a mounting port is arranged at the top of the inner reflection cavity (25), and the outer reflection cavity (24) is connected with the inner reflection cavity (25) through the mounting port.

5. The sensor for measuring density and level of liquid with a single ultrasonic head according to claim 4, wherein ​ 6. The sensor for measuring density and level of liquid with a single ultrasonic head according to claim 5, wherein The outer reflection cavity (24) is an arc structure, and the inner diameter of the arc structure is adapted to the inner diameter of the inner reflection cavity (25), the outer reflection cavity (24) is provided with a connecting end (241) and a mounting end (242), the connecting end (241) is located on the side of the outer reflection cavity (24) protruding outward, the mounting end (242) is located on the side of the outer reflection cavity (24) recessed inward, and the connecting end (241) and the mounting end (242) are in communication, the guide pipe (21) is connected with the outer reflection cavity (24) through the connecting end (241), and the first reflection sheet (23) is arranged on the mounting end (242).

7. The sensor for measuring density and level of liquid with single ultrasonic head according to claim 1, wherein The ultrasonic sensor assembly (3) is composed of an ultrasonic sensor (31), a wire protection tube (32), a pagoda head (33) and a shell (34); The ultrasonic sensor (31) is arranged in the shell (34), the ultrasonic sensor (31) is used for emitting, receiving and analyzing ultrasonic waves, and calculating the density and liquid level of urea solution; The wire protection tube (32) is connected with the pagoda head (33) on the shell (34), and is used for protecting the wire of the ultrasonic sensor (31) from being corroded by urea solution.

8. The sensor for measuring density and level of liquid with a single ultrasonic head according to claim 1, wherein, The float assembly (1) is composed of a float (11) and a second reflection sheet (12); The float (11) is arranged on the guide pipe (21) and movably connected with the guide pipe (21), when the liquid level changes, the float (11) moves along the guide pipe (21) with the change of the liquid level; The second reflection sheet (12) is arranged at the bottom of the float (11) and oppositely arranged with the first reflection sheet (23), and the second reflection sheet (12) has the function of reflecting ultrasonic waves.

9. The sensor for measuring density and level of a liquid with a single ultrasonic head according to claim 8, wherein The float (11) is provided with a limiting structure, the guide pipe (21) is provided with a matching structure, and the limiting structure and the matching structure are matched to limit the float (11) in the horizontal direction.

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