CN114046858B - Anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof - Google Patents
Anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof Download PDFInfo
- Publication number
- CN114046858B CN114046858B CN202111329198.4A CN202111329198A CN114046858B CN 114046858 B CN114046858 B CN 114046858B CN 202111329198 A CN202111329198 A CN 202111329198A CN 114046858 B CN114046858 B CN 114046858B
- Authority
- CN
- China
- Prior art keywords
- module
- test
- liquid level
- ultrasonic
- waveguide tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/296—Acoustic waves
- G01F23/2962—Measuring transit time of reflected waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/30—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats
- G01F23/64—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats of the free float type without mechanical transmission elements
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Electromagnetism (AREA)
- Thermal Sciences (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
The invention provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and an operation method thereof, which are characterized in that spherical magnetic floats are arranged to meet ultrasonic detection applicable to various tilting states, a calibration cylinder is arranged, and standard parameters of different liquids and different environments are measured through a calibration piezoelectric sheet and a calibration reflecting block in the calibration cylinder, so that accurate measurement of the measured liquid is adaptively realized.
Description
Technical Field
The invention belongs to the technical field of liquid level measurement, and particularly relates to an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and an operation method thereof.
Background
Liquid level sensors that measure liquid level using the principle of the time difference from the emission to the reflection of ultrasonic waves have been widely used in the field of measurement and control techniques. The current common technical scheme is as follows.
1. The ultrasonic sensor is arranged above the measured liquid, the ultrasonic wave passes through the air to reach the liquid level, and no obstacle exists in the middle. The liquid level is measured by the time difference between the emission of ultrasonic waves in air and the reflection. The advantage of this solution is non-contact measurement, but the limitations in use are: ① When the air is close to 0 ℃, the piezoelectric sheet generating and receiving ultrasonic waves will frost, so that the measurement is disabled; ② When there is fluctuation in the surface of the measured liquid and the liquid container is inclined, the reflected wave reflection path deviates from the defined measuring line, so that the measuring result has large error and even fails. Such sensors are generally applied to ground fixation and at normal temperatures.
2. The ultrasonic sensor is arranged at the bottom in the measuring cylinder, the length of the measuring cylinder is slightly larger than the maximum height of the liquid level, and the float for tracking the liquid level surface is not arranged. The measuring cylinder is required to be vertically arranged at the bottom of the liquid to be measured in use, and the liquid level is measured by utilizing the time difference between the ultrasonic wave emitted from the bottom of the liquid to the reflection of the liquid level surface. The scheme is generally used for measuring the aviation kerosene liquid level (the freezing point temperature is lower than-55 ℃) on the passenger plane with low mobility, and the precision is high. But there are limitations to some special applications. For example, vehicles with very high mobility and very variable attitude, the reflected wave reflection path will deviate from the defined measuring line due to the liquid surface being non-perpendicular to the measuring line, resulting in a large error or even failure of the measurement result.
3. The ultrasonic sensor is arranged at the bottom of the measuring cylinder, and a floater tracking the liquid level surface is arranged in the measuring cylinder. The geometry of the float is cylindrical. The guide of the floater adopts a steel wire, and an inner cylindrical surface or an outer cylindrical surface. The lower end face of the cylindrical float is used for reflecting ultrasonic waves during measurement. The normal line of the end face of the floater with the structure can be always aligned with the end face of the ultrasonic conversion ring, namely, the measuring path of ultrasonic passing is kept on a defined measuring line without being influenced by the posture, the acceleration and the liquid fluctuation of the container. But the accuracy and stability and reliability are to be improved. The reason is that when the float tracks the liquid level, the float is influenced by the static friction force of the guide pair of the guide mechanism, and particularly under the conditions of large inclination and large acceleration, the tracking process can generate a clamping stagnation phenomenon, so that the error of the measurement result is large and even fails.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and an operation method thereof, wherein the ultrasonic detection applicable to various tilting states is satisfied by arranging a spherical magnetic floater, a calibration cylinder is arranged, and standard parameters of different liquids and different environments are measured by a calibration piezoelectric plate and a calibration reflecting block in the calibration cylinder, so that the accurate measurement of the measured liquid is adaptively realized.
The invention has the following specific implementation contents:
The invention provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system which is arranged in a liquid container, is connected with a signal processing system and is used for measuring measured liquid in the liquid container, and comprises a waveguide tube vertically arranged in the liquid container; a protective base is arranged at the bottom of the waveguide tube, and a measuring piezoelectric sheet which is arranged in the waveguide tube and transmits ultrasonic waves upwards is arranged on the protective base; the bottom side of the waveguide tube is provided with a through hole, and the tested liquid circulates between the liquid container and the waveguide tube through the through hole;
a floating ball which floats on the liquid level surface of the measured liquid is arranged at a position above the measuring piezoelectric sheet in the waveguide tube;
The waveguide tube is provided with a temperature measurement and junction box, and the temperature measurement and junction box is connected with the measurement piezoelectric plate and the signal processing system;
a standard block is arranged on the inner wall of the waveguide tube;
The signal processing system comprises an excitation and receiving circuit, a voltage limiting and filtering circuit, a precise program-controlled amplifying circuit, a high-speed AD conversion circuit, a high-speed data stream storage circuit, a singlechip module and a communication module which are connected in sequence; the precise program-controlled amplifying circuit is also connected with the singlechip module; the excitation and receiving circuit is connected with the temperature measuring and junction box.
In order to better realize the invention, the wall thickness of the waveguide tube is one half of the propagation wavelength of the sound wave in the waveguide tube.
In order to better realize the invention, the device further comprises a matching layer, wherein the matching layer is arranged in the waveguide tube and positioned at the upper position of the measuring piezoelectric sheet;
Defining the characteristic impedance of the measuring piezoelectric sheet as Z 1, the characteristic impedance of the matching layer as Z 2, the characteristic impedance of the measured liquid as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet to the measured liquid as T, the wavelength of sound wave in the matching layer as lambda 2, and the thickness of the matching layer as d 1;
The characteristic impedance of the matching layer satisfies Thickness of matching layerWherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
The invention also provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system which is arranged in the liquid container, is connected with the signal processing system and is used for measuring the measured liquid in the liquid container, and comprises a waveguide tube vertically arranged in the liquid container; a protective base is arranged at the bottom of the waveguide tube, and a measuring piezoelectric sheet which is arranged in the waveguide tube and transmits ultrasonic waves upwards is arranged on the protective base; the bottom side of the waveguide tube is provided with a through hole, and the tested liquid circulates between the liquid container and the waveguide tube through the through hole;
a floating ball which floats on the liquid level surface of the measured liquid is arranged at a position above the measuring piezoelectric sheet in the waveguide tube;
The waveguide tube is provided with a temperature measurement and junction box, and the temperature measurement and junction box is connected with the measurement piezoelectric plate and the signal processing system;
a standard block is arranged on the inner wall of the waveguide tube;
the signal processing system comprises a power supply module, a voltage stabilizing module, a temperature acquisition module, a 422 communication module, an active clock, a self-test module, a buffer module, an excitation module, an ultrasonic sensor, a limiting and pre-amplifying module, a gain band-pass filtering module, a primary program-controlled amplifying module, a secondary program-controlled amplifying module, a low-pass filtering module, an AD module and a singlechip;
The voltage stabilizing module, the temperature acquisition module, the 422 communication module, the active clock, the self-test module, the cache module and the excitation module are respectively connected with the singlechip;
The power supply module is respectively connected with the voltage stabilizing module and the excitation module;
the excitation module is sequentially connected with the ultrasonic sensor, the amplitude limiting and pre-amplifying module, the gain band-pass filtering module, the primary program-controlled amplifying module, the secondary program-controlled amplifying module, the low-pass filtering module, the AD module and the buffer module.
In order to better realize the invention, the wall thickness of the waveguide tube is one half of the propagation wavelength of the sound wave in the waveguide tube.
In order to better realize the invention, the invention further comprises a protection base and a sealing cover; the sealing cover is arranged at the top end of the waveguide tube and is in sealing connection with the top end of the interior of the liquid container;
The bottom end of the protection base is in sealing connection with the bottom end of the inside of the liquid container, and the bottom end of the waveguide tube is sleeved and fixed in the waveguide tube from the upper end of the protection base;
The inside bottom of protection base sets up the backing layer, measurement piezoelectric patch sets up in the bottom of wave guide and is located the top of backing layer.
In order to better realize the invention, further, the back lining layer is a mixture of spherical tungsten powder and epoxy resin, and steel balls are uniformly doped in the mixture of the spherical tungsten powder and the epoxy resin; the diameter of the steel ball is between 0.3mm and 0.7 mm.
In order to better realize the invention, the device further comprises a matching layer, wherein the matching layer is arranged in the waveguide tube and positioned at the upper position of the measuring piezoelectric sheet;
Defining the characteristic impedance of the measuring piezoelectric sheet as Z 1, the characteristic impedance of the matching layer as Z 2, the characteristic impedance of the measured liquid as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet to the measured liquid as T, the wavelength of sound wave in the matching layer as lambda 2, and the thickness of the matching layer as d 1;
The characteristic impedance of the matching layer satisfies Thickness of matching layerWherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
The invention also provides an operation method of the anti-tilting and anti-fluctuation ultrasonic liquid level sensor system, which is based on the anti-tilting and anti-fluctuation ultrasonic liquid level sensor system, and specifically comprises the following steps:
step1: initializing parameters;
step 2: running a test program;
Step 3: performing self-test and outputting self-test results, wherein the self-test results comprise three conditions: outputting a test mark, wherein the self-test result is incorrect and correct; when the self-test result is wrong, the feedback test result exceeds the standard, the test parameters are reset, and the test is performed again;
step 4: when the self-test result is correct, performing a self-gain judgment flow;
Step 5: when the self-gain is judged to be inappropriate, starting a self-gain algorithm, and carrying out judgment again;
step 6: when the self-gain is judged to be proper in gain, the high-low liquid level area is identified, the identification result is divided into a low liquid level area and a high liquid level area, and then the low liquid level area parameter setting or the high liquid level area parameter setting is correspondingly carried out;
step 7: triggering an excitation signal after the low liquid level region parameter setting or the high liquid level region parameter setting is carried out;
step 8: performing excitation and data sampling;
step 9: performing median filtering operation, zero point alignment absolute value taking operation and half-wave detection operation on the sampled data to obtain processed sampled data;
Step 10: repeating the steps 8 and 9 for a plurality of times, performing waveform superposition processing on the processed sampling data obtained for a plurality of times, and then performing high-order wave filtering processing;
Step 11: sequentially carrying out mean value recursive filtering and Kalman filtering operation on the sampled data after the high-order wave filtering treatment;
step 12: after mean recursive filtering and Kalman filtering operations are carried out, slope method feature point identification and related algorithm feature point identification are respectively carried out; then, feature points are judged by the feature points identified by the slope method and the feature points identified by the related algorithm;
step 13: and (3) respectively carrying out the following operations according to the identification of the high liquid level area and the low liquid level area in the step (6):
processing characteristic points corresponding to the sampling data of the low liquid level area by adopting an arithmetic progression method;
Processing the characteristic points corresponding to the sampling data of the high liquid level area by adopting a ranking method;
Step 14: for the sampled data of the ultrasonic wave processed by adopting an arithmetic progression method, carrying out sound velocity correction by combining a temperature signal;
For the ultrasonic sampling data processed by adopting the displacement method, the ultrasonic signal and the temperature signal reflected by the standard block are combined to carry out sound velocity correction;
Step 15: judging the liquid level of the data subjected to sound velocity correction;
Step 16: correcting the mechanical blind area and the floating ball after the liquid level judgment to obtain a specific liquid level value;
Step 17: carrying out Kalman filtering and continuity judgment on the measurement result of the liquid level value, judging the liquid level value with the continuity judged as unqualified as liquid level data in a large rolling gesture, and nullifying;
step 18: and outputting the data with the continuity judged to be qualified as the tested liquid level height data.
In order to better implement the present invention, further, the step 3: the specific operation of the self-test is as follows:
After starting the self-test operation, respectively performing hardware self-test and software self-test;
the hardware self-test comprises a power supply voltage test, an amplifier test and an acoustic wave measurement test; outputting a test identifier after the test is qualified;
The software self-test comprises algorithm test, and a test identifier is output after the test is qualified.
Compared with the prior art, the invention has the following advantages:
(1) Compared with the traditional cylindrical and steel wire floats, the spherical floats are free from clamping stagnation between the guide rails, friction is reduced, and meanwhile, the spherical floats can be compatible to various inclination angles and acceleration fluctuation;
(2) In order to radiate the sound wave of the piston sound source into the medium with larger transmissivity, a matching layer technology is adopted at the piston sound source, in order to reduce the intensity of the reflected wave sound field, the sound wave is transmitted out of the pipe wall as far as possible at the pipe wall so as to radiate outside the circular pipe, and the principle of a circular pipe sound transmission window is adopted to reduce the amplitude of part of the sound wave in a high-order mode;
(3) The backing layer is added to reduce the influence of the bottom echo on excitation and the interference of bottom clutter on a measurement signal;
And a matched calculation method is adopted to realize accurate measurement under the spherical floater.
Drawings
Fig. 1 is a schematic diagram of a signal processing system according to embodiment 1;
fig. 2 is a schematic diagram of a signal processing system according to embodiment 2;
FIG. 3 is a partial schematic of a flow diagram of an operating method;
FIG. 4 is a schematic diagram of a portion of the flowchart of the method of operation of FIG. 3;
FIG. 5 is a schematic diagram of a subsequent portion of the flow diagram of the method of operation of FIGS. 3 and 4;
FIG. 6 is a schematic diagram of a subsequent portion of the flow diagram of the method of operation of FIGS. 3,4 and 5;
FIG. 7 is a schematic flow chart of the self-test;
FIG. 8 is a schematic view showing the structure of the sensor of the present invention installed in a liquid container;
FIG. 9 is a schematic diagram of a specific structure of a sensor;
FIG. 10 is a schematic illustration of a normal incidence zone medium interface of a measurement piezoelectric patch, matching layer and liquid under test;
FIG. 11 is a schematic illustration of the interface of the liquid under test and the waveguide;
FIG. 12 shows a round tube according to the invention schematic diagram of sound field of sound transmission window;
FIG. 13 is a schematic view of the acoustic field in a waveguide from the emission of ultrasonic waves to the return of reflected waves in accordance with the present invention;
FIG. 14 is a schematic diagram of an ultrasonic signal waveform;
FIG. 15 is a schematic diagram showing the measurement state with and without the float ball tilted;
FIG. 16 is a schematic diagram of an original echo;
FIG. 17 is a schematic diagram of a signal wave processed by a software algorithm;
FIG. 18 is a waveform diagram of a complete original signal wave;
FIG. 19 is a schematic diagram of waveforms identified by feature locations;
FIG. 20 is a waveform schematic of a high level waveform;
FIG. 21 is a schematic waveform diagram of a low level waveform subjected to an arithmetic progression process;
Fig. 22 is a schematic waveform diagram of the echo after the echo is ranked.
Wherein: 1. the liquid container comprises a liquid container body, 2, a waveguide tube, 3, a protection base, 4, a calibration cylinder, 5, a calibration piezoelectric sheet, 6, a calibration reflecting block, 7, a measurement piezoelectric sheet, 8, measured liquid, 9, a liquid level surface, 10, a floating ball, 11, a sealing cover, 12, a backing layer, 13, a matching layer, 14, a conversion ring, 15, an anti-collision metal net, 16, a side silicone rubber ring, 17, a bottom silicone rubber ring, 18, a reference block, 19, a temperature measurement junction box, 20, a standard block, A, a main wave, B, a reference block reflected wave, C and a high order wave.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it should be understood that the described embodiments are only some embodiments of the present invention, but not all embodiments, and therefore should not be considered as limiting the scope of protection. All other embodiments, which are obtained by a worker of ordinary skill in the art without creative efforts, are within the protection scope of the present invention based on the embodiments of the present invention.
In the description of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; or may be directly connected, or may be indirectly connected through an intermediate medium, or may be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1:
The embodiment provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system which is arranged in a liquid container 1 and is connected with a signal processing system for measuring measured liquid 8 in the liquid container 1, as shown in fig. 1, wherein the ultrasonic liquid level sensor system comprises a waveguide tube 2 vertically arranged in the liquid container 1; a protective base 3 is arranged at the bottom of the waveguide tube 2, and a measuring piezoelectric sheet 7 which is arranged in the waveguide tube 2 and transmits ultrasonic waves upwards is arranged on the protective base 3; the bottom side of the waveguide tube 2 is provided with a through hole, and the measured liquid 8 flows between the liquid container 1 and the waveguide tube 2 through the through hole;
A floating ball 10 floating on the liquid level surface 9 of the measured liquid 8 is arranged at a position above the measuring piezoelectric sheet 7 in the waveguide tube 2;
a temperature measuring and junction box 19 is arranged on the waveguide tube 2, and the temperature measuring and junction box 19 is connected with a measuring piezoelectric plate and the signal processing system;
a standard block 20 is arranged on the inner wall of the waveguide tube 2;
The signal processing system comprises an excitation and receiving circuit, a voltage limiting and filtering circuit, a precise program-controlled amplifying circuit, a high-speed AD conversion circuit, a high-speed data stream storage circuit, a singlechip module and a communication module which are connected in sequence; the precise program-controlled amplifying circuit is also connected with the singlechip module; the excitation and receiving circuit is connected to the temperature measuring and junction box 19.
In order to better implement the present invention, further, the wall thickness of the waveguide 2 is one half of the propagation wavelength of the acoustic wave in the waveguide 2.
In order to better implement the invention, further comprising a matching layer 13, said matching layer 13 being arranged in said waveguide 2 at a position above the measuring piezoelectric patch 7;
Defining the characteristic impedance of the measuring piezoelectric sheet 7 as Z 1, the characteristic impedance of the matching layer 13 as Z 2, the characteristic impedance of the measured liquid 8 as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet 7 into the measured liquid 8 as T, the wavelength of sound wave in the matching layer 13 as lambda 2, and the thickness of the matching layer 13 as d 1;
the characteristic impedance of the matching layer 13 satisfies Thickness of matching layer 13Wherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
Example 2:
The embodiment also provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor system which is arranged in a liquid container 1 and is connected with a signal processing system for measuring measured liquid 8 in the liquid container 1, as shown in fig. 2, and comprises a waveguide tube 2 vertically arranged in the liquid container 1; a protective base 3 is arranged at the bottom of the waveguide tube 2, and a measuring piezoelectric sheet 7 which is arranged in the waveguide tube 2 and transmits ultrasonic waves upwards is arranged on the protective base 3; the bottom side of the waveguide tube 2 is provided with a through hole, and the measured liquid 8 flows between the liquid container 1 and the waveguide tube 2 through the through hole;
A floating ball 10 floating on the liquid level surface 9 of the measured liquid 8 is arranged at a position above the measuring piezoelectric sheet 7 in the waveguide tube 2;
a temperature measuring and junction box 19 is arranged on the waveguide tube 2, and the temperature measuring and junction box 19 is connected with a measuring piezoelectric plate and the signal processing system;
a standard block 20 is arranged on the inner wall of the waveguide tube 2;
the signal processing system comprises a power supply module, a voltage stabilizing module, a temperature acquisition module, a 422 communication module, an active clock, a self-test module, a buffer module, an excitation module, an ultrasonic sensor, a limiting and pre-amplifying module, a gain band-pass filtering module, a primary program-controlled amplifying module, a secondary program-controlled amplifying module, a low-pass filtering module, an AD module and a singlechip;
The voltage stabilizing module, the temperature acquisition module, the 422 communication module, the active clock, the self-test module, the cache module and the excitation module are respectively connected with the singlechip;
The power supply module is respectively connected with the voltage stabilizing module and the excitation module;
the excitation module is sequentially connected with the ultrasonic sensor, the amplitude limiting and pre-amplifying module, the gain band-pass filtering module, the primary program-controlled amplifying module, the secondary program-controlled amplifying module, the low-pass filtering module, the AD module and the buffer module.
In order to better implement the present invention, further, the wall thickness of the waveguide 2 is one half of the propagation wavelength of the acoustic wave in the waveguide 2.
In order to better realize the invention, the invention further comprises a protection base 3 and a sealing cover 11; the sealing cover 11 is arranged at the top end of the waveguide tube 2 and is in sealing connection with the top end of the interior of the liquid container 1;
the protection base 3 is of a cylindrical structure with an opening at the upper end, the bottom end of the protection base 3 is in sealing connection with the bottom end of the inside of the liquid container 1, and the bottom end of the waveguide 2 is sleeved and fixed in the waveguide 2 from the upper end of the protection base 3;
A backing layer 12 is arranged at the bottom end inside the protective base 3, and the measuring piezoelectric sheet 7 is arranged at the bottom of the waveguide 2 and above the backing layer 12.
In order to better realize the invention, further, the backing layer 12 is a mixture of spherical tungsten powder and epoxy resin, and steel balls are uniformly doped in the mixture of the spherical tungsten powder and the epoxy resin; the diameter of the steel ball is between 0.3mm and 0.7 mm.
In order to better implement the invention, further comprising a matching layer 13, said matching layer 13 being arranged in said waveguide 2 at a position above the measuring piezoelectric patch 7;
Defining the characteristic impedance of the measuring piezoelectric sheet 7 as Z 1, the characteristic impedance of the matching layer 13 as Z 2, the characteristic impedance of the measured liquid 8 as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet 7 into the measured liquid 8 as T, the wavelength of sound wave in the matching layer 13 as lambda 2, and the thickness of the matching layer 13 as d 1;
the characteristic impedance of the matching layer 13 satisfies Thickness of matching layer 13Wherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
Other portions of this embodiment are the same as those of embodiment 1 described above, and thus will not be described again.
Example 3:
In this embodiment, based on the above embodiment 2, as shown in fig. 3, fig. 4, fig. 5, fig. 6, and fig. 7, in which fig. 3, fig. 4, fig. 5, and fig. 6 sequentially form a complete flow diagram, and the flow diagram is divided into four parts for long length; the operation method of the anti-tilting and anti-fluctuation ultrasonic liquid level sensor system is also provided, and the operation method specifically comprises the following steps of:
step1: initializing parameters;
step 2: running a test program;
Step 3: performing self-test and outputting self-test results, wherein the self-test results comprise three conditions: outputting a test mark, wherein the self-test result is incorrect and correct; when the self-test result is wrong, the feedback test result exceeds the standard, the test parameters are reset, and the test is performed again;
step 4: when the self-test result is correct, performing a self-gain judgment flow;
Step 5: when the self-gain is judged to be inappropriate, starting a self-gain algorithm, and carrying out judgment again;
step 6: when the self-gain is judged to be proper in gain, the high-low liquid level area is identified, the identification result is divided into a low liquid level area and a high liquid level area, and then the low liquid level area parameter setting or the high liquid level area parameter setting is correspondingly carried out;
step 7: triggering an excitation signal after the low liquid level region parameter setting or the high liquid level region parameter setting is carried out;
step 8: performing excitation and data sampling;
step 9: performing median filtering operation, zero point alignment absolute value taking operation and half-wave detection operation on the sampled data to obtain processed sampled data;
Step 10: repeating the steps 8 and 9 for a plurality of times, performing waveform superposition processing on the processed sampling data obtained for a plurality of times, and then performing high-order wave filtering processing;
Step 11: sequentially carrying out mean value recursive filtering and Kalman filtering operation on the sampled data after the high-order wave filtering treatment;
step 12: after mean recursive filtering and Kalman filtering operations are carried out, slope method feature point identification and related algorithm feature point identification are respectively carried out; then, feature points are judged by the feature points identified by the slope method and the feature points identified by the related algorithm;
step 13: and (3) respectively carrying out the following operations according to the identification of the high liquid level area and the low liquid level area in the step (6):
processing characteristic points corresponding to the sampling data of the low liquid level area by adopting an arithmetic progression method;
Processing the characteristic points corresponding to the sampling data of the high liquid level area by adopting a ranking method;
Step 14: for the sampled data of the ultrasonic wave processed by adopting an arithmetic progression method, carrying out sound velocity correction by combining a temperature signal;
For the ultrasonic sampling data processed by adopting the displacement method, the ultrasonic signal and the temperature signal reflected by the standard block are combined to carry out sound velocity correction;
Step 15: judging the liquid level of the data subjected to sound velocity correction;
Step 16: correcting the mechanical blind area and the floating ball after the liquid level judgment to obtain a specific liquid level value;
Step 17: carrying out Kalman filtering and continuity judgment on the measurement result of the liquid level value, judging the liquid level value with the continuity judged as unqualified as liquid level data in a large rolling gesture, and nullifying;
step 18: and outputting the data with the continuity judged to be qualified as the tested liquid level height data.
In order to better implement the present invention, further, the step 3: the specific operation of the self-test is as follows:
After starting the self-test operation, respectively performing hardware self-test and software self-test;
the hardware self-test comprises a power supply voltage test, an amplifier test and an acoustic wave measurement test; outputting a test identifier after the test is qualified;
The software self-test comprises algorithm test, and a test identifier is output after the test is qualified.
Working principle: the original echo signal of the sensor is shown in fig. 16, after recursive filtering and median filtering denoising, the signal is subjected to half-wave detection, and finally the waveform is subjected to the albert envelope to obtain a wave packet of the signal shown in fig. 17. Fig. 18 is an overall original waveform, and fig. 19 is a signal envelope waveform after the above-described processing method. The characteristics of the signal wave packet in the high liquid level area are shown as a single wave in fig. 20, and the signal sequencing concludes that the furthest wave packet position is the position of the characteristic point. The characteristic of the signal wave packet in the low liquid level region is shown in fig. 21, and besides the leftmost excitation wave, there are two or more echo wave packets, and an arithmetic series method should be applied at this time, the wave packets are distributed in an arithmetic series, that is, the wave packet positions are in an arithmetic series to obtain the characteristic position as the acoustic wave which returns to the transducer first. As shown in fig. 22, when the sensor introduces the reference ring or the floating ball to the bottom of the sensor, the sensor needs to be ordered according to the position of the wave packet by using a displacement method, and the sequence is the reference ring wave floating ball wave and the possible high-order wave, the amplitude of which is Yu Fuqiu waves, and the ordering of the amplitude of which can be distinguished. In summary, the liquid level signal is obtained according to various algorithms and methods, and finally the liquid level height data is obtained. Table 1 shows measurements at different angles of page tilt, and it can be seen that the sensor is fully applicable in the range of 0 to 60 degrees of tilt. The vertical static precision experimental results shown in the table 2 indicate that the sensor has higher precision in measuring the liquid level height and has important popularization value.
Table 1 anti-tilt test data
Table 2 static vertical accuracy test
Other portions of this embodiment are the same as any of embodiments 1-2 described above, and thus will not be described again.
Example 4:
the embodiment also provides an anti-tilting and anti-fluctuation ultrasonic liquid level sensor which is arranged in a liquid container 1and is connected with a signal processing system, and as shown in fig. 8 and 9, the ultrasonic liquid level sensor comprises a waveguide tube 2 which is vertically arranged in the liquid container 1and the upper end and the lower end of which are respectively connected with the upper end and the lower end of the inside of the liquid container 1; the thickness of the tube wall of the waveguide tube 2 is one half of the propagation wavelength of the sound wave in the waveguide tube 2; a temperature sensor is arranged on the outer wall of the waveguide tube 2;
the liquid container 1 is internally provided with a tested liquid 8, and a plurality of flow guide holes for enabling the tested liquid 8 to circulate between the liquid container 1 and the waveguide 2 are circumferentially arranged on the waveguide 2;
A measuring piezoelectric plate 7 connected with a signal processing system is arranged at the bottom of the waveguide tube 2, a conversion ring 14 is arranged on the measuring piezoelectric plate 7, and a floating ball 10 which floats along with the liquid level surface 9 of the measured liquid 8 is arranged above the measuring piezoelectric plate 7 in the waveguide tube 2;
A calibration cylinder 4 is arranged at the outer side of the bottom end of the waveguide tube 2 in the liquid container 1, and a plurality of guide holes for enabling the measured liquid 8 to circulate between the liquid container 1 and the calibration cylinder 4 are circumferentially arranged on the calibration cylinder 4;
the calibration cylinder 4 is internally provided with a calibration piezoelectric sheet 5 connected with a signal processing system and a calibration block matched with the calibration piezoelectric sheet 5.
Working principle: firstly, sending an excitation pulse to the calibration piezoelectric sheet 5 in the calibration cylinder 4 through a signal processing system, so that the calibration piezoelectric sheet 5 is excited to emit ultrasonic vibration;
Secondly, when ultrasonic waves emitted by the calibration piezoelectric sheet 5 are transmitted to the calibration reflection block 6 to generate reflected waves, the ultrasonic wave crossing time t 0 of the calibration piezoelectric sheet 5 and the calibration reflection block 6 is obtained according to an ultrasonic wave principle, and on the basis of knowing the fixed distance L 0 between the calibration piezoelectric sheet 5 and the calibration reflection block 6, the real-time sound velocity V is obtained according to a speed-time distance formula;
then, an excitation pulse is sent to the measurement piezoelectric sheet 7 in the waveguide tube 2 through a signal processing system, so that the measurement piezoelectric sheet 7 is excited to emit ultrasonic vibration;
then, when the ultrasonic wave emitted by the measuring piezoelectric sheet 7 is transmitted to the lower surface of the floating ball 10, a reflected wave reflected back to the measuring piezoelectric sheet 7 is generated, and finally, the liquid level L of the measured liquid 8 is obtained according to a speed-time distance formula.
Example 5:
The present embodiment further includes a protection base 3 and a sealing cover 11, as shown in fig. 9, on the basis of embodiment 4; the sealing cover 11 is arranged at the top end of the waveguide tube 2 and is in sealing connection with the top end of the interior of the liquid container 1; the protection base 3 is of a cylindrical structure with an opening at the upper end, the bottom end of the protection base 3 is in sealing connection with the bottom end of the inside of the liquid container 1, and the bottom end of the waveguide 2 is sleeved and fixed in the waveguide 2 from the upper end of the protection base 3; a backing layer 12 is arranged at the bottom end inside the protective base 3, and the measuring piezoelectric sheet 7 is arranged at the bottom of the waveguide 2 and above the backing layer 12. The backing layer 12 is a mixture of spherical tungsten powder and epoxy resin, and steel balls are uniformly doped in the mixture of the spherical tungsten powder and the epoxy resin; the diameter of the steel ball is between 0.3mm and 0.7 mm.
Working principle: the backing layer 12 is added to reduce the effect of the floor echo on the excitation and the interference of the floor clutter on the measurement signal.
Other portions of this embodiment are the same as those of embodiment 4 described above, and thus will not be described again.
Example 6:
This embodiment further includes a side silicone rubber ring 16 and a bottom silicone rubber ring 17 as shown in fig. 9, in order to better realize the present invention, on the basis of the above embodiments 4-5; said lateral silicone rubber ring 16 is arranged inside the protective base 3 at the outside of the backing layer 12; said bottom silicone rubber ring 17 is arranged inside the protective base 3 at the bottom of the backing layer 12.
Other portions of this embodiment are the same as any of embodiments 4 to 5 described above, and thus will not be described again.
Example 7:
this embodiment further includes a matching layer 13 as shown in fig. 8,9, 10, 11, and 12, where the matching layer 13 is disposed in the waveguide 2 at a position above the measurement piezoelectric sheet 7;
Defining the characteristic impedance of the measuring piezoelectric sheet 7 as Z 1, the characteristic impedance of the matching layer 13 as Z 2, the characteristic impedance of the measured liquid 8 as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet 7 into the measured liquid 8 as T, the wavelength of sound wave in the matching layer 13 as lambda 2, and the thickness of the matching layer 13 as d 1;
the characteristic impedance of the matching layer 13 satisfies Thickness of matching layer 13Wherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
Working principle: in order to radiate the sound wave emitted by the piston sound source, namely the measuring piezoelectric sheet 7, into the medium with larger transmissivity, a matching layer technology is adopted at the position of the piston sound source, namely the measuring piezoelectric sheet 7, in order to reduce the intensity of the reflected wave sound field, the sound wave is transmitted out of the pipe wall at the pipe wall of the waveguide 2 as far as possible, so that the sound wave is radiated to the outside of the waveguide 2, and the circular pipe sound transmission window principle is adopted to reduce the amplitude of the sound wave in a part of high-order modes.
As shown in fig. 10, considering the case of the normal incidence band dielectric interface, the characteristic impedance of the measurement piezoelectric sheet 7 is Z 1, the characteristic impedance of the matching layer 13 is Z 2, the thickness of the matching layer 13 is d 1, and the characteristic impedance of the measured liquid 8 is Z 3. The transmission coefficient of the sound intensity transmitted by the measurement piezoelectric sheet 7 into the measured liquid 8 is T, namely:
when the characteristic impedance of the matching layer 13 is satisfied And thickness ofWhere λ 2 is the wavelength of the acoustic wave in the matching layer 13, N e N, transmission coefficient t=1. Such matching layer technique is employed to enhance the energy coupling of the measurement piezo-electric sheet 7 into the liquid 8 under test.
As shown in fig. 11, the characteristic impedance of the waveguide 2 is Z4, the wavelength of the acoustic wave in the waveguide 2 is λ 4, and the thickness of the waveguide 2 is d 2, similarly, the interface between the liquid 8 to be measured and the waveguide 2 is two layers. When the thickness d 2 of the waveguide 2 is atIn the vicinity, the transmission coefficient of sound waves radiated from the liquid 8 to be measured into the liquid medium through the waveguide is approximately 1. At this time, the waveguide functions as an acoustic window. With the increase of the incident angle, especially when the incident angle is larger than the critical angle, total reflection occurs, so that a part of sound waves scattered by the rigid floating ball is transmitted by the sound transmission window, and the influence of high-order mode waves is reduced.
As shown in FIG. 12, a schematic view of a sound field of a circular tube sound-transmitting window is shown, water is adopted as a liquid medium, a 304 stainless steel floating ball is adopted as a rigid floating ball, a carbon fiber composite circular tube is adopted as a waveguide tube, the thickness of the tube wall is equal to 1.25mm about one-half of the wavelength, polytetrafluoroethylene is adopted as a matching layer, and the thickness of the matching layer is equal to 1mm about one-fourth of the wavelength. The ultrasonic liquid level sensor has the advantages that the energy of part of waves in a high-order mode is reduced, the signal to noise ratio is improved, and meanwhile, compared with a traditional metal circular tube sensor, the quality is greatly reduced, so that the ultrasonic liquid level sensor is light.
Other portions of this embodiment are the same as any of embodiments 4 to 6 described above, and thus will not be described again.
Example 8:
The present embodiment further comprises an anti-collision metal mesh 15 on the basis of any one of the above embodiments 4 to 7, wherein the anti-collision metal mesh 15 is installed at the bottom of the waveguide tube 2 and is located between the measurement piezoelectric sheet 7 and the floating ball 10. Working principle: the floating ball 10 is prevented from colliding with the measuring piezoelectric sheet 7 by providing the anti-collision metal net 15. Other portions of this embodiment are the same as any of embodiments 4 to 7 described above, and thus will not be described again.
Example 9:
In this embodiment, on the basis of any one of the above embodiments 4 to 8, the floating ball 10 is made of stainless steel 304, and is hollow spherical, with a diameter of 35mm, a roundness error of ±0.1mm, a mirror polished surface, and a ball wall thickness of 0.3mm of the floating ball 10; the waveguide tube 2 is a carbon fiber composite material circular tube, the length of the tube is 1000mm, the inner diameter is 36mm, the outer diameter is 38.5mm, 3 phi 4 guide holes are uniformly distributed in the circumferential direction of the bottom end and the middle end of the waveguide tube 2, and the inner wall of the waveguide tube 2 is sprayed with polyurethane wave-absorbing materials with the thickness of 0.01 mm; the calibrating cylinder 4 is made of a carbon fiber composite material, the length of the cylinder is 150mm, the inner diameter is 15mm, the outer diameter is 17mm, and 2 phi 3 deflector holes are circumferentially and uniformly distributed at the bottom end and the middle end of the calibrating cylinder 4; the protection base 3 is made of aviation aluminum; the measuring piezoelectric plate 7 and the calibrating piezoelectric plate 5 are piezoelectric ceramics with the frequency of 1MHz, the diameter phi 35mm and the diameter phi 15mm and the piezoelectric coefficient of more than 800 multiplied by 10 -3 C/N. Other portions of this embodiment are the same as any of embodiments 4 to 8 described above, and thus will not be described again.
Example 10:
In this embodiment, on the basis of any one of the above embodiments 4 to 9, taking the waveguide tube 2 with a height of 330mm as an example, as shown in fig. 13, fig. 13 is a schematic state flow chart of a sound field from the emission of ultrasonic waves from the measurement piezoelectric plate 7 to the reflection of ultrasonic waves back through the floating ball 10 in sequence from left to right, it can be seen that an ultrasonic wave main wave a is emitted from the measurement piezoelectric plate 7, a reference block 18 is disposed in the waveguide tube 2, the ultrasonic wave main wave a is reflected by the reference block reflected wave B reflected by the reference block 18, and the ultrasonic wave main wave a is reflected back to the measurement piezoelectric plate 7 after passing through the floating ball 10 and is brought back to a part of the high-order wave C. The right side in fig. 13 is a pressure gauge for distinguishing total sound field pressure, wherein the color corresponds to the corresponding sound field pressure value in the sound field schematic diagram, because the color of the background of the waveguide 2 is green and corresponds to between-1×10 3 Pa and 1×10 3 Pa on the pressure gauge, the colors in the waveguide 2 in different states of the ultrasonic main wave a, the reference block reflected wave B and the high-order wave C are difficult to distinguish after being converted into black-white pictures, so the description is made in the form of data below the waveguide 2 in the corresponding state in fig. 13, although the distinguishing colors are not shown in fig. 13, the description is not substantially influenced by the technical scheme described in the present application because fig. 13 is a test data screenshot, and therefore the description is made. It should be noted that, fig. 18, fig. 19, fig. 20, fig. 21, fig. 22 are only the computer interface screen shots, and the test interface of the instrument software is black-matrix white lines, which are only shown as the test effect, and do not have any substantial effect on the specific content of the present application, so the applicant requests to keep the effect diagram display in this form.
Other portions of this embodiment are the same as any of embodiments 1 to 6 described above, and thus will not be described again.
Example 11:
the embodiment provides an application method of an anti-tilting and anti-fluctuation ultrasonic liquid level sensor, which is based on the anti-tilting and anti-fluctuation ultrasonic liquid level sensor and is characterized by comprising the following steps:
Firstly, sending an excitation pulse to the calibration piezoelectric sheet 5 in the calibration cylinder 4 through a signal processing system, so that the calibration piezoelectric sheet 5 is excited to emit ultrasonic vibration;
Secondly, when ultrasonic waves emitted by the calibration piezoelectric sheet 5 are transmitted to the calibration reflection block 6 to generate reflected waves, the ultrasonic wave crossing time t 0 of the calibration piezoelectric sheet 5 and the calibration reflection block 6 is obtained according to an ultrasonic wave principle, and on the basis of knowing the fixed distance L 0 between the calibration piezoelectric sheet 5 and the calibration reflection block 6, the real-time sound velocity V is obtained according to a speed-time distance formula;
then, an excitation pulse is sent to the measurement piezoelectric sheet 7 in the waveguide tube 2 through a signal processing system, so that the measurement piezoelectric sheet 7 is excited to emit ultrasonic vibration;
then, when the ultrasonic wave emitted by the measuring piezoelectric sheet 7 is transmitted to the lower surface of the floating ball 10, a reflected wave reflected back to the measuring piezoelectric sheet 7 is generated, and finally, the liquid level L of the measured liquid 8 is obtained according to a speed-time distance formula.
Example 12:
The embodiment provides a signal processing method of an anti-tilting and anti-fluctuation ultrasonic liquid level sensor, which is used for performing ultrasonic calculation processing in an application method of the anti-tilting and anti-fluctuation ultrasonic liquid level sensor, and comprises the following steps:
firstly, enveloping echo by adopting full wave detection;
Then, the position Pmax of the maximum correlation coefficient Pis obtained by adopting an autocorrelation algorithm, wherein the window size of the autocorrelation algorithm is half of the envelope width, namely half of the width of the Gaussian narrow pulse;
Then, the slope Ki of the curve corresponding to the half envelope width in the echo is obtained, a slope comparison value is set, and the slope Ki is judged after the position Pmax with the maximum correlation coefficient P is obtained: when the slope Ki is greater than the set slope comparison value, the position Pmax is determined as the echo position, and otherwise, the position Pmax is not determined as the echo position.
Example 13:
In this embodiment, in order to better realize the present invention, in addition to the above embodiment 12, a high liquid level region and a low liquid level region are set in the liquid container 1, and for the low liquid level region, there are a plurality of positions P (i) having close correlation coefficients and having an arithmetic progression, and the liquid level height is determined in the low liquid level region by using a time difference between the position P (i) and the position P (i-1).
Other portions of this embodiment are the same as those of embodiment 12, and thus will not be described again.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present invention fall within the scope of the present invention.
Claims (9)
1. An anti-tilting and anti-fluctuation ultrasonic liquid level sensor system which is arranged in a liquid container (1) and is connected with a signal processing system for measuring measured liquid (8) in the liquid container (1), and is characterized by comprising a waveguide tube (2) vertically arranged in the liquid container (1); a protective base (3) is arranged at the bottom of the waveguide tube (2), and a measuring piezoelectric sheet (7) which is arranged in the waveguide tube (2) and transmits ultrasonic waves upwards is arranged on the protective base (3); the bottom side of the waveguide tube (2) is provided with a through hole, and the tested liquid (8) flows between the liquid container (1) and the waveguide tube (2) through the through hole;
A floating ball (10) floating on a liquid level surface (9) of the measured liquid (8) is arranged at a position above the measuring piezoelectric sheet (7) in the waveguide tube (2);
a temperature measurement and junction box (19) is arranged on the waveguide tube (2), and the temperature measurement and junction box (19) is connected with a measurement piezoelectric plate and the signal processing system;
a standard block (20) is arranged on the inner wall of the waveguide tube (2);
The signal processing system comprises an excitation and receiving circuit, a voltage limiting and filtering circuit, a precise program-controlled amplifying circuit, a high-speed AD conversion circuit, a high-speed data stream storage circuit, a singlechip module and a communication module which are connected in sequence; the precise program-controlled amplifying circuit is also connected with the singlechip module; the excitation and receiving circuit is connected with the temperature measuring and junction box (19);
the device also comprises a matching layer (13), wherein the matching layer (13) is arranged in the waveguide tube (2) and positioned at the upper position of the measuring piezoelectric sheet (7);
Defining the characteristic impedance of the measuring piezoelectric sheet (7) as Z 1, the characteristic impedance of the matching layer (13) as Z 2, the characteristic impedance of the measured liquid (8) as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet (7) into the measured liquid (8) as T, the wavelength of sound wave in the matching layer (13) as lambda 2, and the thickness of the matching layer (13) as d 1;
the characteristic impedance of the matching layer (13) is as follows Thickness of matching layer (13)Wherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
2. An anti-tilt and anti-surge ultrasonic level sensor system according to claim 1, wherein the wall thickness of the waveguide (2) is one half the wavelength of the sound wave propagating in the waveguide (2).
3. An anti-tilting and anti-fluctuation ultrasonic liquid level sensor system which is arranged in a liquid container (1) and is connected with a signal processing system for measuring measured liquid (8) in the liquid container (1), and is characterized by comprising a waveguide tube (2) vertically arranged in the liquid container (1); a protective base (3) is arranged at the bottom of the waveguide tube (2), and a measuring piezoelectric sheet (7) which is arranged in the waveguide tube (2) and transmits ultrasonic waves upwards is arranged on the protective base (3); the bottom side of the waveguide tube (2) is provided with a through hole, and the tested liquid (8) flows between the liquid container (1) and the waveguide tube (2) through the through hole;
A floating ball (10) floating on a liquid level surface (9) of the measured liquid (8) is arranged at a position above the measuring piezoelectric sheet (7) in the waveguide tube (2);
a temperature measurement and junction box (19) is arranged on the waveguide tube (2), and the temperature measurement and junction box (19) is connected with a measurement piezoelectric plate and the signal processing system;
a standard block (20) is arranged on the inner wall of the waveguide tube (2);
the signal processing system comprises a power supply module, a voltage stabilizing module, a temperature acquisition module, a 422 communication module, an active clock, a self-test module, a buffer module, an excitation module, an ultrasonic sensor, a limiting and pre-amplifying module, a gain band-pass filtering module, a primary program-controlled amplifying module, a secondary program-controlled amplifying module, a low-pass filtering module, an AD module and a singlechip;
The voltage stabilizing module, the temperature acquisition module, the 422 communication module, the active clock, the self-test module, the cache module and the excitation module are respectively connected with the singlechip;
The power supply module is respectively connected with the voltage stabilizing module and the excitation module;
the excitation module is sequentially connected with the ultrasonic sensor, the amplitude limiting and pre-amplifying module, the gain band-pass filtering module, the primary program-controlled amplifying module, the secondary program-controlled amplifying module, the low-pass filtering module, the AD module and the buffer module.
4. An anti-tilt and anti-surge ultrasonic level sensor system according to claim 3, wherein the wall thickness of the waveguide (2) is one half the wavelength of the sound wave propagating in the waveguide (2).
5. An ultrasonic level sensor system resistant to tilting and waving according to claim 3, further comprising a protective base (3) and a closure cap (11); the sealing cover (11) is arranged at the top end of the waveguide tube (2) and is connected with the top end of the inside of the liquid container (1) in a sealing way;
The protection base (3) is of a cylindrical structure with an opening at the upper end, the bottom end of the protection base (3) is in sealing connection with the bottom end of the inside of the liquid container (1), and the bottom end of the waveguide tube (2) is sleeved and fixed in the waveguide tube (2) from the upper end of the protection base (3);
the bottom end inside the protection base (3) is provided with a backing layer (12), and the measuring piezoelectric sheet (7) is arranged at the bottom of the waveguide tube (2) and is positioned above the backing layer (12).
6. An anti-tilt and anti-surge ultrasonic level sensor system according to claim 5, wherein said backing layer (12) is a mixture of spherical tungsten powder and epoxy resin, and steel balls are also uniformly doped in the mixture of spherical tungsten powder and epoxy resin; the diameter of the steel ball is between 0.3mm and 0.7 mm.
7. An anti-tilt and anti-surge ultrasonic level sensor system according to claim 3, further comprising a matching layer (13), said matching layer (13) being disposed within said waveguide (2) at a position above the measuring piezoelectric patch (7);
Defining the characteristic impedance of the measuring piezoelectric sheet (7) as Z 1, the characteristic impedance of the matching layer (13) as Z 2, the characteristic impedance of the measured liquid (8) as Z 3, the transmission coefficient of sound intensity transmitted from the measuring piezoelectric sheet (7) into the measured liquid (8) as T, the wavelength of sound wave in the matching layer (13) as lambda 2, and the thickness of the matching layer (13) as d 1;
the characteristic impedance of the matching layer (13) is as follows Thickness of matching layer (13)Wherein n is a positive integer; the transmission coefficient t=1, and the calculation formula of the transmission coefficient T is as follows:
where ω is the angular frequency of the ultrasonic wave and C2 is the speed of sound of the ultrasonic wave in the matching layer.
8. A method of operating an anti-tilt and anti-surge ultrasonic level sensor system, based on claim 3, characterized by the specific steps of:
step1: initializing parameters;
step 2: running a test program;
Step 3: performing self-test and outputting self-test results, wherein the self-test results comprise three conditions: outputting a test mark, wherein the self-test result is incorrect and correct; when the self-test result is wrong, the feedback test result exceeds the standard, the test parameters are reset, and the test is performed again;
step 4: when the self-test result is correct, performing a self-gain judgment flow;
Step 5: when the self-gain is judged to be inappropriate, starting a self-gain algorithm, and carrying out judgment again;
step 6: when the self-gain is judged to be proper in gain, the high-low liquid level area is identified, the identification result is divided into a low liquid level area and a high liquid level area, and then the low liquid level area parameter setting or the high liquid level area parameter setting is correspondingly carried out;
step 7: triggering an excitation signal after the low liquid level region parameter setting or the high liquid level region parameter setting is carried out;
step 8: performing excitation and data sampling;
step 9: performing median filtering operation, zero point alignment absolute value taking operation and half-wave detection operation on the sampled data to obtain processed sampled data;
Step 10: repeating the steps 8 and 9 for a plurality of times, performing waveform superposition processing on the processed sampling data obtained for a plurality of times, and then performing high-order wave filtering processing;
Step 11: sequentially carrying out mean value recursive filtering and Kalman filtering operation on the sampled data after the high-order wave filtering treatment;
step 12: after mean recursive filtering and Kalman filtering operations are carried out, slope method feature point identification and related algorithm feature point identification are respectively carried out; then, feature points are judged by the feature points identified by the slope method and the feature points identified by the related algorithm;
step 13: and (3) respectively carrying out the following operations according to the identification of the high liquid level area and the low liquid level area in the step (6):
processing characteristic points corresponding to the sampling data of the low liquid level area by adopting an arithmetic progression method;
Processing the characteristic points corresponding to the sampling data of the high liquid level area by adopting a ranking method;
Step 14: for the sampled data of the ultrasonic wave processed by adopting an arithmetic progression method, carrying out sound velocity correction by combining a temperature signal;
For the ultrasonic sampling data processed by adopting the displacement method, the ultrasonic signal and the temperature signal reflected by the standard block are combined to carry out sound velocity correction;
Step 15: judging the liquid level of the data subjected to sound velocity correction;
Step 16: correcting the mechanical blind area and the floating ball after the liquid level judgment to obtain a specific liquid level value;
Step 17: carrying out Kalman filtering and continuity judgment on the measurement result of the liquid level value, judging the liquid level value with the continuity judged as unqualified as liquid level data in a large rolling gesture, and nullifying;
step 18: and outputting the data with the continuity judged to be qualified as the tested liquid level height data.
9. A method of operating an anti-tilt and anti-surge ultrasonic level sensor system according to claim 8, wherein said step 3: the specific operation of the self-test is as follows:
After starting the self-test operation, respectively performing hardware self-test and software self-test;
the hardware self-test comprises a power supply voltage test, an amplifier test and an acoustic wave measurement test; outputting a test identifier after the test is qualified;
The software self-test comprises algorithm test, and a test identifier is output after the test is qualified.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111329198.4A CN114046858B (en) | 2021-11-10 | 2021-11-10 | Anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111329198.4A CN114046858B (en) | 2021-11-10 | 2021-11-10 | Anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114046858A CN114046858A (en) | 2022-02-15 |
| CN114046858B true CN114046858B (en) | 2024-08-13 |
Family
ID=80208539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111329198.4A Active CN114046858B (en) | 2021-11-10 | 2021-11-10 | Anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114046858B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119197703B (en) * | 2024-09-14 | 2026-01-06 | 四川泛华航空仪表电器有限公司 | A method, system, equipment and medium for measuring airborne fuel level |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104266716A (en) * | 2014-09-24 | 2015-01-07 | 中山欧麦克仪器设备有限公司 | An Ultrasonic Liquid Level Measuring Device Against Tilt and Fluctuation |
| CN109540263A (en) * | 2019-01-14 | 2019-03-29 | 四川大学 | A kind of onboard ultrasound wave liquid level emasuring device of light-duty electromagnetism interference |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7421895B1 (en) * | 2005-04-21 | 2008-09-09 | Caldwell Joseph W | Fluid level measuring system |
| JP2011002326A (en) * | 2009-06-18 | 2011-01-06 | Ricoh Elemex Corp | Ultrasonic liquid level meter |
| CN101634580A (en) * | 2009-08-28 | 2010-01-27 | 四川大学 | Ultrasonic liquid level measuring sensor capable of resisting inclination and fluctuation |
| CN104266721A (en) * | 2014-09-24 | 2015-01-07 | 中山欧麦克仪器设备有限公司 | Integrated ultrasonic liquid level gauge |
| CN209945506U (en) * | 2019-06-06 | 2020-01-14 | 上海思寒环保科技有限公司 | Anti-electromagnetic interference ultrasonic liquid level measuring device |
-
2021
- 2021-11-10 CN CN202111329198.4A patent/CN114046858B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104266716A (en) * | 2014-09-24 | 2015-01-07 | 中山欧麦克仪器设备有限公司 | An Ultrasonic Liquid Level Measuring Device Against Tilt and Fluctuation |
| CN109540263A (en) * | 2019-01-14 | 2019-03-29 | 四川大学 | A kind of onboard ultrasound wave liquid level emasuring device of light-duty electromagnetism interference |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114046858A (en) | 2022-02-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1123946A (en) | Ultrasonic transducer with reference reflector | |
| CN114046857B (en) | Anti-tilting and anti-fluctuation ultrasonic liquid level sensor, application and processing method | |
| CN106338320B (en) | System and method for non-invasive continuous level measurement of liquids | |
| US10352911B2 (en) | Airborne ultrasound testing system for a test object | |
| US6584860B1 (en) | Flow probe insertion gauge | |
| CN114046858B (en) | Anti-tilting and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof | |
| Licznerski et al. | Ultrasonic system for accurate distance measurement in the air | |
| WO2020113671A1 (en) | System and method for detecting electromagnetic characteristic of object by using terahertz electromagnetic wave | |
| CN108267102A (en) | A kind of segment difference detection device and segment difference detection method | |
| JPH07333202A (en) | Flaw detector of piping | |
| JPS6315104A (en) | Inner-hole mapping device and method | |
| CN120507284A (en) | Photoelastic spectrum gas concentration detection device and method based on annular absorption tank | |
| CN114216849B (en) | Self-adaptive laser ultrasonic curved surface workpiece nondestructive testing device | |
| US4061040A (en) | Apparatus for measuring rotation rates with acoustic waves | |
| US7421901B2 (en) | Method of using ultrasound to inspect a part in immersion | |
| JP2002044773A (en) | Acoustic lens and ultrasonic transmitter | |
| EP3873324A1 (en) | Device for optoacoustic imaging and corresponding control method | |
| US6937352B1 (en) | Positioning device for RAM testing system | |
| US5101382A (en) | Acoustic imaging method and apparatus for nondestructive evaluation of materials | |
| SU1760650A1 (en) | Process of determination of sensitivity of electroacoustic converter by reciprocity method | |
| JPH0714936Y2 (en) | Ultrasonic transducer | |
| EP1393821A1 (en) | Ultrasonic transducer | |
| JPH10142029A (en) | Level gauge | |
| JP2667684B2 (en) | Focus transducer | |
| KR20260004821A (en) | Medium characteristics inspection device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |