Double-ultrasonic detection device

Abstract

The utility model discloses a double-ultrasonic detection device, which comprises a shell in which a detection cavity is formed and is used for accommodating liquid to be detected; the first ultrasonic reflection part is arranged on the rigid side wall of the detection cavity and is used for reflecting an ultrasonic signal; the first ultrasonic detection part is arranged on the side wall of the detection cavity, is opposite to the first ultrasonic reflection part and is used for acquiring first flight time when the ultrasonic waves sent by the first ultrasonic detection part reach the first ultrasonic reflection part and are reflected and returned; the second ultrasonic reflection part is arranged on the elastic side wall of the detection cavity and used for reflecting the ultrasonic signals, and the outward expansion distance of the elastic side wall of the detection cavity is related to the pressure of the to-be-detected liquid received at the position; the second ultrasonic detection part is arranged on the side wall of the detection cavity, is opposite to the second ultrasonic reflection part and is used for acquiring second flight time when the ultrasonic waves sent by the second ultrasonic detection part reach the second ultrasonic reflection part and are reflected and returned. The liquid level detection device is applied to liquid concentration and liquid level height detection, and can improve the liquid level height detection accuracy.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrasonic detection of material characteristics, in particular to a dual ultrasonic detection device. Background Art

[0002] Ultrasonic detection of fluid density or concentration, as well as ultrasonic detection of fluid volume or height, utilizes the principle that ultrasonic waves have different wave speeds in fluids of different densities. The specific technical implementation uses a timing chip to measure the flight time of ultrasonic waves within a fixed distance to express the fluid density or height.

[0003] One of the application scenarios of this technology is that the automotive industry needs to use a kind of blue-added urea in the exhaust treatment system of fuel vehicles to eliminate harmful substances such as nitrogen monoxide or nitrogen dioxide, collectively referred to as NOx, in the exhaust gas. In order to achieve precise reaction, it is necessary to measure the concentration of the reactant blue-added urea and dynamically report the urea liquid level in its carrier container.

[0004] There are two solutions on the market. The first is that the concentration is detected by ultrasonic technology, and the liquid level is detected by reed tube or Hall chip superimposed with magnetic floating ring technology; the second is a dual-super solution in which both concentration and liquid level are achieved by ultrasonic technology.

[0005] The dual-ultrasound solution uses two probes in conjunction with the same control panel to detect both concentration and liquid level. Both technologies involve transmitting ultrasonic waves directly through the urea liquid. For concentration, a fixed distance is set for the ultrasonic wave to travel through this distance to obtain its flight time, while for liquid level, the flight time is obtained by directly using the ultrasonic wave to reach the liquid surface.

[0006] The dual-super solution shares the same application scenarios, core technologies, underlying electronic circuits, and detection logic. This allows for shared hardware resources, significantly reducing costs and making it a future mainstream technology. However, the dual-super solution has several drawbacks: The ultrasonic wave must reach the surface of the liquid being measured. If the liquid level is too high or the fluid on the surface experiences violent oscillations due to vehicle vibrations, the returned signal will be dispersed and very weak, leading to undetectable or false alarms. If the liquid level is low, the free space in the liquid is too large and the surface is violently agitated, resulting in distorted detection values. Utility Model Content

[0007] The purpose of the utility model is to provide a dual ultrasonic detection device for detecting liquid concentration and liquid level height in order to improve the accuracy of liquid level detection in view of the defects and shortcomings of the existing technology.

[0008] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0009] A dual ultrasonic detection device, characterized by comprising:

[0010] A housing having a detection cavity formed therein for accommodating a liquid to be detected;

[0011] a first ultrasonic reflector, provided on a rigid side wall of the detection cavity, for reflecting ultrasonic signals;

[0012] a first ultrasonic detection unit, disposed on a side wall of the detection cavity and opposite to the first ultrasonic reflection unit, for obtaining a first flight time of an ultrasonic wave transmitted by the first ultrasonic reflection unit and reflected back;

[0013] A second ultrasonic reflector is provided on the elastic side wall of the detection cavity, and is used to reflect ultrasonic signals. The outward expansion distance of the elastic side wall of the detection cavity is related to the pressure of the liquid to be measured at the elastic side wall;

[0014] The second ultrasonic detection part is arranged on the side wall of the detection cavity and is opposite to the second ultrasonic reflection part, and is used to obtain the second flight time of the ultrasonic wave sent by it reaching the second ultrasonic reflection part and returning after being reflected.

[0015] Optionally, the elastic side wall of the detection cavity is provided with a pressure sensitive membrane.

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

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

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

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

[0020] Optionally, the second ultrasonic reflecting portion 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, the air cavity is provided with a spring, and the spring abuts against the center of the pressure sensitive membrane.

[0023] Optionally, a pressure ring and a pressure bowl are provided between the shell and the back cover, which are used to clamp the outer edge of the corrugated area of ​​the pressure-sensitive membrane; the pressure ring abuts the back cover, the pressure bowl abuts the shell, and a second through hole connected to the first through hole is provided at the bottom of the pressure bowl, and the skirt of the pressure-sensitive membrane abuts the outer edge of the pressure bowl and the shell and the back cover.

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

[0025] Optionally, the liquid inlet is provided with a filter.

[0026] Optionally, a circuit board is further included, wherein the circuit board is provided with:

[0027] a control module connected to the first ultrasonic detection unit and the second ultrasonic detection unit, for receiving and processing ultrasonic detection signals;

[0028] A timing module, connected to the control module, for providing timing for ultrasonic ranging;

[0029] A communication module, connected to the control module, for communicating with the host computer to transmit data and control signals;

[0030] The power supply module is used to provide an appropriate power supply voltage for the electronic devices of the device.

[0031] Optionally, the maximum distance that the elastic side wall of the detection cavity expands outward is not greater than the product of the minimum second flight speed in the full value range and the ultrasonic vibration period, and the second flight speed is the distance between the second ultrasonic reflecting part and the second ultrasonic detection part divided by the second flight time.

[0032] After adopting the above technical solution, the beneficial effects of the utility model are:

[0033] While inheriting the advantages of the dual-ultrasonic solution, the embodiment of the utility model adopts a method of indirectly detecting the liquid level by using a pressure transmission mechanism, which can avoid the distortion of the detection value caused by the large free space of the low-level liquid and the violent agitation of the liquid surface, and avoid the interference of the high-level signal attenuation of the measured liquid on the ultrasonic detection, which can significantly improve the accuracy of liquid level height detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 is a schematic cross-sectional view of a dual ultrasonic detection device according to some embodiments;

[0036] Figure 2 is a stereoscopic diagram of a dual ultrasonic detection device according to some embodiments;

[0037] Figure 3 is a stereoscopic diagram of a dual ultrasonic detection device from another perspective in some embodiments;

[0038] Figure 4 is a schematic AA cross-sectional view of a dual ultrasonic detection device according to some embodiments;

[0039] Figure 5 is a schematic cross-sectional view of a dual ultrasonic detection device BB according to some embodiments;

[0040] Figure 6 is a schematic cross-sectional view of a dual ultrasonic detection device CC according to some embodiments;

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

[0042] Figure 8 are schematic cross-sectional views of pressure-sensitive membranes according to some embodiments;

[0043] Figure 9 are schematic cross-sectional views of pressure-sensitive membranes and air cavities according to some embodiments;

[0044] Figure 10 is a schematic cross-sectional view of a dual ultrasonic detection device BB according to some embodiments;

[0045] Figure 11 is an electrical hardware block diagram of a dual ultrasonic detection device according to some embodiments;

[0046] Figure 12 Schematic diagram of ultrasonic detection windowing in some embodiments.

[0047] Description of reference numerals:

[0048] 100. Shell; 110. Detection cavity; 120. Pressure-sensitive membrane; 121. Plane; 122. Corrugated area; 123. Skirt; 130. Back cover; 131. Pressure ring; 132. Pressure bowl; 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; 200. First ultrasonic reflecting part; 300. First ultrasonic detection part; 400. Second ultrasonic reflecting part; 500. Second ultrasonic detection part; 600. Circuit board; 610. Control module; 620. Timing module; 630. Communication module; 640. Power module. DETAILED DESCRIPTION

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

[0050] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

[0051] The utility model relates to a dual-ultrasonic detection device, which is applied to liquid concentration and liquid level detection 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 reflecting portion 200 , a first ultrasonic detecting portion 300 , a second ultrasonic reflecting portion 400 and a second ultrasonic detecting portion 500 .

[0053] A detection cavity 110 is formed in the housing 100 for accommodating the liquid to be tested. In some embodiments, the liquid to be tested is a blue-added urea liquid.

[0054] The first ultrasonic reflector 200 is disposed on the rigid sidewall of the detection cavity 110 to reflect ultrasonic signals. The rigid sidewall of the detection cavity 110 does not change state with changes in the liquid level. In some embodiments, the first ultrasonic reflector 200 can be a metal reflector.

[0055] The first ultrasonic detector 300 is disposed on a sidewall of the detection chamber 110 and opposite the first ultrasonic reflector 200. It is used to transmit a first ultrasonic detection signal through the test liquid toward the first ultrasonic reflector 200 and receive the signal reflected by the first ultrasonic reflector 200, thereby determining a first flight time tfc for the transmitted ultrasonic wave to reach the first ultrasonic reflector 200 and be reflected back. The first flight velocity V1 of the transmitted ultrasonic wave in the test liquid is calculated as V1 = D1 / tfc, where D1 is the first flight distance, which is twice the distance D between the first ultrasonic reflector 200 and the first ultrasonic detector 300. Because the first flight velocity V1 is related to the concentration C of the test liquid and the current ambient temperature T, if the current ambient temperature T is known, the concentration C of the test liquid can be further determined by measuring the first flight velocity V1.

[0056] The second ultrasonic reflector 400 is located 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 under test at that location. Because 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 from the liquid surface at that location, the liquid level H can be determined by measuring the outward expansion distance dx of the elastic sidewall, combined with the measured liquid concentration C.

[0057] The second ultrasonic detector 500 is disposed on the sidewall of the detection cavity, opposite the second ultrasonic reflector 400. It transmits a second ultrasonic detection signal through the test liquid toward the second ultrasonic reflector 400 and receives the signal reflected by the second ultrasonic reflector 400, thereby determining the second flight time tfh of the transmitted ultrasonic wave reaching the second ultrasonic reflector 400 and returning after reflection. The second flight speed of the transmitted ultrasonic wave in the test liquid 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. This is equal to twice the sum of the distance d between the second ultrasonic reflector 400 and the second ultrasonic detector 500 when the detection cavity 110 is empty, and the distance dx the elastic sidewall expands outward due to the pressure of the test liquid. If the second ultrasonic detector 500 and the first ultrasonic detector 300 transmit the same ultrasonic wave, the first flight speed V1 and the second flight speed V2 will be the same. Therefore, when the current ambient temperature T and the aforementioned concentration C of the liquid to be measured are known, the liquid level H of the liquid to be measured can be further obtained by measuring the second flight time tfh. In some embodiments, the ultrasonic wave transmitted by the second ultrasonic detection unit 500 can be different from that transmitted by the first ultrasonic detection unit 300, and the result can also be obtained through certain numerical transformations.

[0058] While inheriting the advantages of the dual-ultrasonic solution, the embodiment of the utility model adopts a method of indirectly detecting the liquid level by using a pressure transmission mechanism, which has significant advantages. It can avoid the distortion of the detection value caused by the large free space of the low-level liquid and the violent agitation of the liquid surface, and avoid the interference of the high-level signal attenuation of the measured liquid on the ultrasonic detection, which can significantly improve 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 . One side of the pressure sensitive membrane 120 is the liquid to be measured, and the other side is air. The pressure sensitive membrane 120 expands toward the air side as the level of the liquid to be measured increases.

[0060] In another embodiment, the pressure sensitive film 120 is an elastic metal film. In some implementations, the pressure sensitive film 120 can be integrated with the second ultrasonic reflective portion 400 .

[0061] See also Figures 2 to 6In another embodiment, the device further includes a rear cover 130, with an air cavity 140 formed between the pressure-sensitive membrane 120 and the rear cover 130. A liquid channel 150 is provided through the housing 100, communicating with the detection cavity 110. A liquid inlet 151 is formed at the bottom of the housing 100, and a liquid outlet 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 measured contacts one side of the pressure-sensitive membrane 120. The dual ultrasonic detection device of this embodiment can be placed as a probe in the liquid to be measured and sunk to the bottom of the container containing the liquid to be measured. The liquid to be measured flows into the detection cavity 110 through the liquid inlet 151 at the bottom of the liquid channel 150 and can overflow from the liquid outlet 152. Whether the liquid level to be measured is above or below the height of the housing 100, ultrasonic detection of concentration and liquid level can be performed. The pressure of the liquid level to be measured causes the pressure-sensitive membrane 120 to expand toward the air cavity 140.

[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 may be fixed by bolts.

[0064] See also Figure 7 As shown, in another embodiment, the pressure sensitive membrane 120 has a flat surface 121 at its center, and the flat surface 121 transitions to an outermost skirt 123 via a corrugated area 122. The skirt 123 is used for sealing the area and fixing the pressure sensitive membrane 120.

[0065] See also Figure 8 As shown, in another embodiment, the second ultrasonic reflective portion 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 a specific implementation, the pressure sensitive film 120 is made of a highly elastic polymer material.

[0067] See also 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 also Figure 10As shown, in another embodiment, a pressure ring 131 and a pressure bowl 132 are provided between the shell 100 and the back cover 130, which are used to clamp the outer edge of the corrugated area 122 of the pressure sensitive membrane 120; the pressure ring 131 abuts against the back cover 130, and the pressure bowl 132 abuts against the shell 100, and a second through hole 133 connected to the first through hole 160 is provided at the bottom of the pressure bowl 132, and the skirt 123 of the pressure sensitive membrane 120 abuts against the outer edge of the pressure bowl 132 as well as the shell 100 and the back 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 also Figure 3 As shown, in another embodiment, the liquid inlet 152 is provided with a filter (not shown in the figure). The filter can filter out bubbles or dust particles to prevent them from entering the detection area.

[0071] See also Figure 6 and Figure 11 As shown, in another embodiment, the device further includes a circuit board 600, which is provided with 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 detector 300 and the second ultrasonic detector 500 for receiving and processing 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 for providing 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 for communicating with a host computer to transmit data and control signals. In some embodiments, the communication module 630 transmits control information and parameters, i.e., 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 adaptive power supply voltage for the electronic devices of the device.

[0072] In another embodiment, the maximum outward expansion distance dx of the elastic side wall of the detection cavity 110 is max Not greater than the minimum second flight speed V in the entire range 2min and ultrasonic vibration period T c The product of .

[0073] Under this limitation, we have The maximum second flight time tfh measured under the condition of the minimum second flight speed in the full range V2max half, The minimum second flight time tfh measured under the condition of the minimum second flight speed in the full range V2min Half of This design can reduce the signal-to-noise ratio requirements of the ultrasonic time-of-flight timing circuit hardware.

[0074] See also Figure 12 As shown, the windowing time tw is in the middle of the ultrasonic envelope Wu, which can further avoid the low signal-to-noise ratio area in front of the first wave. The implementation of this strategy includes the following points: (1) The system design arranges the flight time of ultrasonic detection to fall into a narrow space T c (2) After the ultrasonic envelope is triggered, the software controls the zero-crossing amplitude to have only one flight time detection value tfx; (3) The detection value tfx is continuously subtracted from T c Until: To obtain the true value.

[0075] In some embodiments, the first ultrasonic detector 300 and the second ultrasonic detector 500 may employ ultrasonic Time-of-Flight (ToF) sensors.

[0076] The above is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A dual ultrasonic detection device, characterized in that: include: A housing having a detection cavity formed therein for accommodating a liquid to be detected; a first ultrasonic reflector, provided on a rigid side wall of the detection cavity, for reflecting ultrasonic signals; a first ultrasonic detection unit, disposed on a side wall of the detection cavity and opposite to the first ultrasonic reflection unit, for obtaining a first flight time of an ultrasonic wave transmitted by the first ultrasonic reflection unit and reflected back from the first ultrasonic reflection unit; A second ultrasonic reflector is provided on the elastic side wall of the detection cavity, and is used to reflect ultrasonic signals. The outward expansion distance of the elastic side wall of the detection cavity is related to the pressure of the liquid to be measured at the elastic side wall; The second ultrasonic detection part is arranged on the side wall of the detection cavity and is opposite to the second ultrasonic reflection part, and is used to obtain the second flight time of the ultrasonic wave sent by it reaching the second ultrasonic reflection part and returning after being reflected.

2. A dual ultrasonic detection device according to claim 1, characterized in that: The elastic side wall of the detection cavity is provided with a pressure sensitive membrane.

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

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

5. A dual ultrasonic detection device according to claim 4, characterized in that: The housing is provided with a groove in which a first sealing ring is provided. 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 in the center, which transitions to an outermost skirt via a corrugated area.

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

8. The dual ultrasonic detection device according to claim 6, characterized in that: The material of the pressure sensitive film is a high-elastic polymer material.

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

10. The dual ultrasonic detection device according to claim 6, characterized in that: A pressure ring and a pressure bowl are provided between the shell and the back cover, which are used to clamp the outer edge of the corrugated area of ​​the pressure sensitive membrane; the pressure ring abuts the back cover, the pressure bowl abuts the shell, and a second through hole connected to the first through hole is provided at the bottom of the pressure bowl, and the skirt of the pressure sensitive membrane abuts the outer edge of the pressure bowl and the shell 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 pressing bowl and the shell.

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

13. The dual ultrasonic detection device according to claim 4, characterized in that: Also included is a circuit board having: a control module connected to the first ultrasonic detection unit and the second ultrasonic detection unit, for receiving and processing ultrasonic detection signals; A timing module, connected to the control module, for providing timing for ultrasonic ranging; A communication module, connected to the control module, for communicating with the host computer to transmit data and control signals; The power supply module is used to provide an appropriate power supply voltage for the electronic devices of the device.

14. The dual ultrasonic detection device according to claim 1, characterized in that: The maximum outward expansion distance of the elastic side wall of the detection cavity is no greater than the product of the minimum second flight speed in the full value range and the ultrasonic vibration period, and the second flight speed is the distance between the second ultrasonic reflecting part and the second ultrasonic detecting part divided by the second flight time.

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