Dual ultrasonic detection device

Abstract

The application discloses a double-ultrasonic detecting device, which comprises a shell, a detecting cavity is formed in the shell, and the detecting cavity is used for containing a liquid to be detected; a first ultrasonic reflection part is arranged on a rigid side wall of the detecting cavity and is used for reflecting ultrasonic signals; a first ultrasonic detecting part is arranged on the side wall of the detecting cavity and is opposite to the first ultrasonic reflection part, and is used for obtaining a first flight time of ultrasonic waves sent by the first ultrasonic detecting part, the ultrasonic waves reaching the first ultrasonic reflection part and being reflected to return; a second ultrasonic reflection part is arranged on an elastic side wall of the detecting cavity and is used for reflecting ultrasonic signals; the elastic side wall of the detecting cavity expands outward by a distance which is related to the pressure of the liquid to be detected; and a second ultrasonic detecting part is arranged on the side wall of the detecting cavity and is opposite to the second ultrasonic reflection part, and is used for obtaining a second flight time of ultrasonic waves sent by the second ultrasonic detecting part, the ultrasonic waves reaching the second ultrasonic reflection part and being reflected to return. The application is applied to liquid concentration and liquid level height detection, and can improve the accuracy of liquid level height detection.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic detection of material characteristics, and specifically to a dual ultrasonic detection device. Background Technology

[0002] Ultrasonic detection of fluid density or concentration, as well as fluid volume or height, utilizes the principle that ultrasonic waves travel at different speeds in fluids of varying densities. Specifically, this is achieved by using a timing chip to measure the flight time of the ultrasonic wave over a fixed distance to express the fluid's density or height.

[0003] One application scenario for this technology is in the automotive industry, where a type of urea called "Tianlan Urea" is used in the exhaust gas treatment system of fuel vehicles to eliminate harmful substances such as nitric oxide or nitrogen dioxide, collectively known as NOx. In order to achieve a precise reaction, it is necessary to measure the concentration of the reactant, Tianlan Urea, and to dynamically report the urea level in its carrier container.

[0004] Currently, there are two main approaches to solutions on the market. One approach is to use ultrasonic technology for concentration detection and magnetic float ring technology for liquid level detection, which combines magnetic reed switches or Hall effect chips with magnetic float rings. The other approach is a dual-ultrasound solution where both concentration and liquid level are achieved using ultrasonic technology.

[0005] The dual-ultrasound scheme uses two probes working with the same control board to detect concentration and liquid level. Both methods involve transmitting ultrasonic waves directly through the urea liquid. For concentration, the flight time is obtained by setting a fixed distance for the ultrasonic waves to travel through that distance, while for liquid level, the flight time is obtained by directly measuring the time it takes for the ultrasonic waves to reach the liquid surface.

[0006] Because the dual-ultrasound scheme uses the same application scenarios, core technologies, and underlying electronic circuits and detection logic, it can share hardware resources at the underlying technology level, thus greatly reducing costs and becoming the mainstream technology in the future. However, the dual-ultrasound scheme has a drawback: the ultrasonic wave transmission needs to reach the surface of the liquid being measured. If the liquid level is too high, or the liquid surface vibrates violently due to the bumps caused by the vehicle's movement, the returned signal will be scattered and very weak, making it undetectable or resulting in false alarms. If the liquid level is too low, the free space of the liquid is too large, and the surface agitation is violent, leading to distorted detection values. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings and deficiencies of existing technologies by providing a dual ultrasonic detection device for detecting liquid concentration and liquid level, thereby improving the accuracy of liquid level detection.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A dual ultrasonic detection device, characterized in that it comprises:

[0010] The housing contains a detection cavity for holding the liquid to be tested;

[0011] The first ultrasonic reflector is disposed on the rigid sidewall of the detection cavity and is used to reflect ultrasonic signals;

[0012] A first ultrasonic detection unit is disposed on the side wall of the detection cavity and opposite to the first ultrasonic reflection unit, and is used to obtain the first flight time of the ultrasonic wave it sends to the first ultrasonic reflection unit and return after reflection.

[0013] The second ultrasonic reflector is disposed on the elastic sidewall of the detection cavity and is used to reflect ultrasonic signals. The outward expansion distance of the elastic sidewall of the detection cavity is related to the pressure of the liquid to be measured at this location.

[0014] The second ultrasonic detector is disposed on the side wall of the detector cavity and opposite to the second ultrasonic reflector, and is used to obtain the second flight time of the ultrasonic wave it sends to the second ultrasonic reflector and return after reflection.

[0015] Optionally, the elastic sidewalls of the detection cavity are provided with pressure-sensitive membranes.

[0016] Optionally, the pressure-sensitive membrane is an elastic metal film.

[0017] Optionally, it also includes a back cover, with an air cavity formed between the pressure-sensitive membrane and the back cover; a liquid channel is provided through the housing, the liquid channel is connected to the detection cavity, and a liquid inlet is formed at the bottom of the housing and a liquid outlet is formed at the top of the housing; the housing is also provided with a first through hole, through which the liquid to be tested contacts the pressure-sensitive membrane.

[0018] Optionally, the housing is provided with a groove, in which a first sealing ring is provided, and the first sealing ring abuts against both the housing and the rear cover.

[0019] Optionally, the pressure-sensitive membrane has a plane at its center, which transitions to the outermost skirt via a corrugated region.

[0020] Optionally, the second ultrasonic reflector is a metal sheet embedded in the plane at the center of the pressure-sensitive membrane.

[0021] Optionally, the pressure-sensitive membrane is made of a highly elastic polymer material.

[0022] Optionally, the pressure-sensitive membrane is made of a non-elastic polymer material, and the air cavity is provided with a spring, which abuts against the center of the pressure-sensitive membrane.

[0023] Optionally, a pressure ring and a pressure cup are provided between the housing and the back cover to clamp the outer edge of the corrugated area of ​​the pressure-sensitive membrane; the pressure ring abuts against the back cover, the pressure cup abuts against the housing, the bottom of the pressure cup is provided with a second through hole communicating with the first through hole, and the skirt of the pressure-sensitive membrane abuts against the outer edge of the pressure cup, as well as the housing and the back cover.

[0024] Optionally, a second sealing ring is provided between the outer edge of the pressure bowl and the housing.

[0025] Optionally, the liquid inlet hole is equipped with a filter screen.

[0026] Optionally, it also includes a circuit board, the circuit board having:

[0027] The control module, connected to the first and second ultrasonic detection units, is used to receive and process ultrasonic detection signals.

[0028] A timing module, connected to the control module, is used to provide timing for ultrasonic ranging;

[0029] A communication module, connected to the control module, is used to communicate with the host computer to transmit data and control signals;

[0030] A power module is used to provide a suitable power voltage for the device's electronic equipment.

[0031] Optionally, the maximum outward expansion distance of the elastic sidewall of the detection cavity is not greater than the product of the minimum second flight speed in the entire range and the ultrasonic vibration period, where the second flight speed is the distance between the second ultrasonic reflector and the second ultrasonic detector divided by the second flight time.

[0032] After adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0033] While inheriting the advantages of the dual-ultrasound scheme, this embodiment of the invention adopts a method of indirectly detecting liquid level using a pressure transmission mechanism. This avoids the distortion of detection values ​​caused by the large free space and violent turbulence of liquid surface at low liquid levels, and also avoids the interference of signal attenuation at high liquid levels on ultrasonic detection, thus significantly improving the accuracy of liquid level height detection. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 These are schematic cross-sectional views of some embodiments of the dual ultrasonic detection device;

[0036] Figure 2 These are perspective views of some embodiments of the dual ultrasonic detection device;

[0037] Figure 3 This is a perspective view of some embodiments of the dual ultrasonic detection device;

[0038] Figure 4 These are schematic diagrams of cross-sections AA of some embodiments of the dual ultrasonic detection device;

[0039] Figure 5 These are schematic diagrams of the BB cross-section of a dual ultrasonic detection device in some embodiments;

[0040] Figure 6 These are schematic diagrams of the CC cross-section of a dual ultrasonic detection device in some embodiments;

[0041] Figure 7 These are schematic diagrams of pressure-sensitive membranes in some embodiments;

[0042] Figure 8 These are schematic diagrams of the cross-sections of pressure-sensitive membranes in some embodiments;

[0043] Figure 9 These are schematic diagrams of the pressure-sensitive membrane and air cavity cross-sections in some embodiments;

[0044] Figure 10 These are schematic diagrams of the BB cross-section of a dual ultrasonic detection device in some embodiments;

[0045] Figure 11 These are electrical hardware block diagrams of some embodiments of a dual ultrasonic detection device;

[0046] Figure 12 These are schematic diagrams of ultrasonic detection windowing in some embodiments.

[0047] Explanation of reference numerals in the attached figures:

[0048] 100. Housing; 110. Detection cavity; 120. Pressure-sensitive membrane; 121. Plane; 122. Corrugated area; 123. Skirt; 130. Back cover; 131. Pressure ring; 132. Pressure cup; 133. Second through hole; 140. Air cavity; 141. Spring; 150. Liquid channel; 151. Liquid inlet; 152. Liquid outlet; 160. First through hole; 170. Groove; 171. First sealing ring; 180. Filter cavity; 181. Filter screen; 200. First ultrasonic reflector; 300. First ultrasonic detector; 400. Second ultrasonic reflector; 500. Second ultrasonic detector; 600. Circuit board; 610. Control module; 620. Timing module; 630. Communication module; 640. Power module. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to the accompanying drawings.

[0050] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive element, but such modifications are protected by patent law as long as they fall within the scope of the claims of the present invention.

[0051] This invention relates to a dual ultrasonic detection device, which is used for detecting liquid concentration and liquid level, and can significantly improve the accuracy of liquid level detection.

[0052] Reference Figure 1 As shown, an embodiment of a dual ultrasonic detection device includes a housing 100, a first ultrasonic reflector 200, a first ultrasonic detector 300, a second ultrasonic reflector 400, and a second ultrasonic detector 500.

[0053] A detection cavity 110 is formed within the housing 100 for containing the liquid to be tested. In some embodiments, the liquid to be tested is urea solution.

[0054] A first ultrasonic reflector 200 is disposed on the rigid sidewall of the detection cavity 110 for reflecting ultrasonic signals. The rigid sidewall of the detection cavity 110 does not change state with the liquid level. In some embodiments, the first ultrasonic reflector 200 may be a metal reflector.

[0055] The first ultrasonic detection unit 300 is disposed on the side wall of the detection cavity 110 and faces the first ultrasonic reflection unit 200. It is used to send a first ultrasonic detection signal through the liquid to be tested to the first ultrasonic reflection unit 200 and to receive the signal reflected by the first ultrasonic reflection unit 200, thereby obtaining the first flight time tfc of the transmitted ultrasonic wave reaching the first ultrasonic reflection unit 200 and returning after reflection. The first flight velocity V1 of the transmitted ultrasonic wave in the liquid to be tested is V1 = D1 / tfc, where D1 is the first flight distance, which is twice the distance D between the first ultrasonic reflection unit 200 and the first ultrasonic detection unit 300. Since the first flight velocity V1 is related to the concentration C of the liquid to be tested and the current ambient temperature T, given the current ambient temperature T, the concentration C of the liquid to be tested can be further obtained by measuring the first flight velocity V1.

[0056] The second ultrasonic reflector 400 is disposed on the elastic sidewall of the detection cavity 110 to reflect ultrasonic signals. The outward expansion distance dx of the elastic sidewall of the detection cavity 110 is related to the pressure of the liquid being measured at that location. Since the liquid pressure on the elastic sidewall is related to the liquid pressure at that location, and the liquid pressure is related to the liquid density and the distance between that location and the liquid surface, the liquid level height H can be obtained by measuring the outward expansion distance dx of the elastic sidewall, in conjunction with the measured liquid concentration C.

[0057] The second ultrasonic detector 500 is disposed on the side wall of the detector cavity and opposite to the second ultrasonic reflector 400. It transmits a second ultrasonic detection signal through the liquid to be tested to the second ultrasonic reflector 400 and receives the signal reflected by the second ultrasonic reflector 400, thereby obtaining the second flight time tfh of the transmitted ultrasonic wave reaching the second ultrasonic reflector 400 and returning after reflection. The second flight velocity of the transmitted ultrasonic wave in the liquid to be tested is V2 = D2 / tfh. D2 is the second flight distance, which is twice the distance between the second ultrasonic reflector 400 and the second ultrasonic detector 500, that is, twice the sum of the distance d between the second ultrasonic reflector 400 and the second ultrasonic detector 500 when the detector cavity 110 is empty and the distance dx by which the elastic sidewall expands outward due to the pressure of the liquid to be tested. If the second ultrasonic detector 500 and the first ultrasonic detector 300 transmit the same ultrasonic wave, then the first flight velocity V1 and the second flight velocity V2 are the same. Therefore, given the current ambient temperature T and the concentration C of the liquid to be tested, the liquid level H can be further obtained by measuring the second flight time tfh. In some embodiments, the ultrasonic waves emitted by the second ultrasonic detection unit 500 may differ from those of the first ultrasonic detection unit 300, and the result can still be obtained through certain numerical transformations.

[0058] While inheriting the advantages of the dual-ultrasound scheme, this embodiment of the invention adopts a method of indirectly detecting liquid level using a pressure transmission mechanism. This method has significant advantages, as it avoids the distortion of detection values ​​caused by the large free space and violent turbulence of liquid surface at low liquid levels. Furthermore, it avoids the interference of signal attenuation at high liquid levels on ultrasonic detection, thus significantly improving the accuracy of liquid level height detection.

[0059] In another embodiment, the elastic sidewall of the detection cavity 110 includes a pressure-sensitive membrane 120, with one side of the pressure-sensitive membrane 120 containing the liquid to be tested and the other side containing air. The pressure-sensitive membrane 120 expands toward the air side as the liquid level of the liquid to be tested increases.

[0060] In another embodiment, the pressure-sensitive membrane 120 is a thin, elastic metal film. In some embodiments, it may be integrated with the second ultrasonic reflector 400.

[0061] See Figures 2 to 6In another embodiment, a rear cover 130 is also included, forming an air cavity 140 between the pressure-sensitive membrane 120 and the rear cover 130. A liquid channel 150 is provided through the housing 100, which is connected to the detection chamber 110. An inlet hole 151 is formed at the bottom of the housing 100, and an outlet hole 152 is formed at the top of the housing 100. The housing 100 also has a first through hole 160, through which the liquid to be tested contacts one side of the pressure-sensitive membrane 120. In this embodiment, a dual ultrasonic detection device can be placed as a single probe in the liquid to be tested, submerged at the bottom of the container holding the liquid. The liquid to be tested flows into the detection chamber 110 through the inlet hole 151 at the bottom of the liquid channel 150 and can overflow from the outlet hole 152. Ultrasonic detection of concentration and liquid level can be performed regardless of whether the liquid level is higher or lower than the height of the housing 100. The pressure-sensitive membrane 120 expands into the air cavity 140 due to the pressure of the liquid level.

[0062] In another embodiment, the housing 100 is provided with a groove 170, in which a first sealing ring 171 is provided. The first sealing ring 171 abuts against both the housing 100 and the rear cover 130. The air cavity 140 can be sealed by the first sealing ring 171.

[0063] In some embodiments, the housing 100 and the rear cover can be secured with bolts.

[0064] See Figure 7 As shown, in another embodiment, the pressure-sensitive membrane 120 has a central plane 121, which transitions via a corrugated region 122 to an outermost skirt 123. The skirt 123 serves to seal the area and fix the pressure-sensitive membrane 120.

[0065] See Figure 8 As shown, in another embodiment, the second ultrasonic reflector 400 is a metal sheet embedded in the plane 121 at the center of the pressure-sensitive membrane 120, for reflecting ultrasonic signals.

[0066] In practice, the pressure-sensitive membrane 120 is made of a highly elastic polymer material.

[0067] See Figure 9 As shown, in another embodiment, the pressure-sensitive membrane 120 is made of a non-elastic polymer material, and the air cavity 140 is provided with a spring 141, which abuts against the center of the pressure-sensitive membrane 120. The spring 141 can provide elastic support for the non-elastic pressure-sensitive membrane 120.

[0068] See Figure 10As shown, in another embodiment, a pressure ring 131 and a pressure cup 132 are provided between the housing 100 and the rear cover 130 to clamp the outer edge of the corrugated area 122 of the pressure-sensitive membrane 120; the pressure ring 131 abuts against the rear cover 130, the pressure cup 132 abuts against the housing 100, and the bottom of the pressure cup 132 is provided with a second through hole 133 communicating with the first through hole 160. The skirt 123 of the pressure-sensitive membrane 120 abuts against the outer edge of the pressure cup 132, as well as the housing 100 and the rear cover 130.

[0069] In another embodiment, a second sealing ring 134 is provided between the outer edge of the pressure bowl 132 and the housing 100 for further sealing the liquid to be tested.

[0070] See Figure 3 As shown, in another embodiment, the liquid inlet 152 is equipped with a filter (not shown in the figure). The filter can filter out air bubbles or dust particles, preventing them from entering the detection area.

[0071] See Figure 6 and Figure 11 As shown, in another embodiment, a circuit board 600 is also included. The circuit board 600 includes a control module 610, a timing module 620, a communication module 630, and a power module 640. The control module 610 is connected to the first ultrasonic detection unit 300 and the second ultrasonic detection unit 500, and is used to receive and process ultrasonic detection signals. In some embodiments, the control module 610 may be an MCU controller. The timing module 620 is connected to the control module 610 and is used to provide timing for ultrasonic ranging. In some embodiments, the timing module 620 may be built into the control module 610. The communication module 630 is connected to the control module 610 and is used to communicate with a host computer to transmit data and control signals. In some embodiments, the communication module 630 transmits control information and parameters (variables) via the J1939 protocol. In some embodiments, the communication module 630 may be built into the control module 610. The power module 640 is used to provide an appropriate power supply voltage for the electronic equipment of the device.

[0072] In another embodiment, the maximum outward expansion distance dx of the elastic sidewalls of the probe cavity 110 is... max Not greater than the second flight speed V, which is the smallest in the entire range. 2min With the ultrasonic vibration period T c The product of.

[0073] Under this constraint, then we have The maximum second flight time tfh measured under the condition of the minimum second flight speed in the entire range. V2max Half of The minimum second flight time tfh measured under the condition of the minimum second flight speed in the entire range. V2min Half of, that is This design allows for a reduction in the signal-to-noise ratio requirements of the timing circuit hardware for ultrasonic time-of-flight.

[0074] See Figure 12 As shown, the windowing time tw is located in the middle of the ultrasonic envelope Wu, which further enables windowing sampling to avoid the low signal-to-noise ratio region in front of the first wave. The implementation of this strategy includes the following key points: (1) The system design arranges the flight time of ultrasonic detection to fall within a narrow space T. c Within the range; (2) after the ultrasonic envelope is triggered, the software controls the zero-crossing amplitude to have only one time-of-flight detection value tfx; (3) the detection value tfx is continuously reduced by T c Until: The truth value can then be obtained.

[0075] In some embodiments, the first ultrasonic detection unit 300 and the second ultrasonic detection unit 500 may employ an ultrasonic time-of-flight (ToF) sensor.

[0076] The above is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A dual ultrasonic detection device, characterized in that, include: The housing contains a detection cavity for holding the liquid to be tested; The first ultrasonic reflector is disposed on the rigid sidewall of the detection cavity and is used to reflect ultrasonic signals; A first ultrasonic detection unit is disposed on the side wall of the detection cavity and opposite to the first ultrasonic reflection unit, and is used to obtain the first flight time of the ultrasonic wave it sends to the first ultrasonic reflection unit and return after reflection. The second ultrasonic reflector is disposed on the elastic sidewall of the detection cavity and is used to reflect ultrasonic signals. The outward expansion distance of the elastic sidewall of the detection cavity is related to the pressure of the liquid to be measured at this location. The second ultrasonic detector is disposed on the side wall of the detector cavity and opposite to the second ultrasonic reflector, and is used to obtain the second flight time of the ultrasonic wave it sends to the second ultrasonic reflector and return after reflection.

2. The dual ultrasonic detection device according to claim 1, characterized in that, The elastic sidewall of the detection cavity is equipped with a pressure-sensitive membrane.

3. The dual ultrasonic detection device according to claim 2, characterized in that, The pressure-sensitive membrane is an elastic metal film.

4. The dual ultrasonic detection device according to claim 2, characterized in that, It also includes a back cover, with an air cavity formed between the pressure-sensitive membrane and the back cover; a liquid channel is provided through the housing, the liquid channel is connected to the detection cavity, and a liquid inlet is formed at the bottom of the housing and a liquid outlet is formed at the top of the housing; the housing is also provided with a first through hole, through which the liquid to be tested contacts the pressure-sensitive membrane.

5. A dual ultrasonic detection device according to claim 4, characterized in that, The housing has a groove, in which a first sealing ring is provided, and the first sealing ring abuts against both the housing and the rear cover.

6. A dual ultrasonic detection device according to claim 4, characterized in that, The pressure-sensitive membrane has a plane at its center, which transitions to the outermost skirt via a corrugated region.

7. A dual ultrasonic detection device according to claim 6, characterized in that, The second ultrasonic reflector is a metal sheet embedded in the plane at the center of the pressure-sensitive membrane.

8. A dual ultrasonic detection device according to claim 6, characterized in that, The pressure-sensitive membrane is made of a highly elastic polymer material.

9. A dual ultrasonic detection device according to claim 6, characterized in that, The pressure-sensitive membrane is made of a non-elastic polymer material, and the air cavity is equipped with a spring that abuts against the center of the pressure-sensitive membrane.

10. A dual ultrasonic detection device according to claim 6, characterized in that, A pressure ring and a pressure cup are provided between the housing and the back cover to clamp the outer edge of the corrugated area of ​​the pressure-sensitive membrane; the pressure ring abuts against the back cover, the pressure cup abuts against the housing, and the bottom of the pressure cup is provided with a second through hole that communicates with the first through hole; the skirt of the pressure-sensitive membrane abuts against the outer edge of the pressure cup, as well as the housing and the back cover.

11. A dual ultrasonic detection device according to claim 10, characterized in that, A second sealing ring is provided between the outer edge of the pressure bowl and the shell.

12. A dual ultrasonic detection device according to claim 4, characterized in that, The liquid inlet is equipped with a filter screen.

13. A dual ultrasonic detection device according to claim 4, characterized in that, It also includes a circuit board, which is provided with: The control module, connected to the first and second ultrasonic detection units, is used to receive and process ultrasonic detection signals. A timing module, connected to the control module, is used to provide timing for ultrasonic ranging; A communication module, connected to the control module, is used to communicate with the host computer to transmit data and control signals; A power module is used to provide a suitable power voltage for the device's electronic equipment.

14. A dual ultrasonic detection device according to claim 1, characterized in that, The maximum outward expansion distance of the elastic sidewall of the detection cavity is no greater than the product of the minimum second flight speed in the entire range and the ultrasonic vibration period, where the second flight speed is the distance between the second ultrasonic reflector and the second ultrasonic detector divided by the second flight time.

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