CN114046858A - Anti-inclination and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof - Google Patents
Anti-inclination and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof Download PDFInfo
- Publication number
- CN114046858A CN114046858A CN202111329198.4A CN202111329198A CN114046858A CN 114046858 A CN114046858 A CN 114046858A CN 202111329198 A CN202111329198 A CN 202111329198A CN 114046858 A CN114046858 A CN 114046858A
- Authority
- CN
- China
- Prior art keywords
- module
- liquid level
- ultrasonic
- test
- 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.)
- Granted
Links
- 239000007788 liquid Substances 0.000 title claims abstract description 210
- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000005259 measurement Methods 0.000 claims abstract description 50
- 238000001514 detection method Methods 0.000 claims abstract description 5
- 238000012360 testing method Methods 0.000 claims description 87
- 238000012545 processing Methods 0.000 claims description 43
- 238000001914 filtration Methods 0.000 claims description 40
- 238000007667 floating Methods 0.000 claims description 36
- 230000005284 excitation Effects 0.000 claims description 31
- 230000005540 biological transmission Effects 0.000 claims description 30
- 230000001681 protective effect Effects 0.000 claims description 28
- 238000005070 sampling Methods 0.000 claims description 15
- 229910000831 Steel Inorganic materials 0.000 claims description 10
- 239000010959 steel Substances 0.000 claims description 10
- 238000004364 calculation method Methods 0.000 claims description 9
- 238000004891 communication Methods 0.000 claims description 9
- 238000012937 correction Methods 0.000 claims description 9
- 230000000670 limiting effect Effects 0.000 claims description 9
- 230000000087 stabilizing effect Effects 0.000 claims description 9
- 239000003822 epoxy resin Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 229920000647 polyepoxide Polymers 0.000 claims description 8
- 238000007789 sealing Methods 0.000 claims description 8
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 230000003139 buffering effect Effects 0.000 claims description 3
- 230000001902 propagating effect Effects 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 19
- 229920002379 silicone rubber Polymers 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 239000004945 silicone rubber Substances 0.000 description 4
- 229920000049 Carbon (fiber) Polymers 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 3
- 239000004917 carbon fiber Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 239000003086 colorant Substances 0.000 description 2
- 230000036961 partial effect Effects 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 239000010963 304 stainless steel Substances 0.000 description 1
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000002592 echocardiography Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- -1 polytetrafluoroethylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
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
本发明提出了一种抗倾斜和波动的超声波液位传感器系统及其运行方法，通过设置圆球形的磁浮子，满足在各种倾斜状态下适用的超声波检测，并设置校准筒，通过校准筒中的校准压电片和校准反射块实现对不同液体和不同环境下的标准参数的测定，进而适应性实现对被测液体的精准测量。
The invention provides an ultrasonic liquid level sensor system with anti-tilt and fluctuation and an operation method thereof. By setting a spherical magnetic float, it can satisfy the ultrasonic detection applicable in various tilting states, and a calibration cylinder is set. The calibration piezoelectric sheet and calibration reflective block realize the measurement of standard parameters in different liquids and different environments, and then adapt to achieve accurate measurement of the liquid to be measured.
Description
Technical Field
The invention belongs to the technical field of liquid level measurement, and particularly relates to an anti-inclination and anti-fluctuation ultrasonic liquid level sensor system and an operation method thereof.
Background
Liquid level sensors that measure liquid level using the time difference between transmission and reflection of ultrasonic waves have been widely used in the field of measurement and control technology. The current common technical schemes are two types:
1. the ultrasonic sensor is arranged above the liquid to be detected, the ultrasonic wave reaches the liquid level through the air, and no obstacle exists in the middle. The liquid level is measured by the time difference between the emission and reflection of the ultrasonic waves in the air. The advantage of this solution is non-contact measurement, but the limitations in use are: firstly, when the air is close to 0 ℃, the piezoelectric sheet generating and receiving ultrasonic waves frosts, so that the measurement is invalid; secondly, when the surface of the liquid to be measured fluctuates and the liquid container inclines, the reflection path of the reflected wave deviates from the defined measurement line, so that the measurement result has large error and even fails. The sensor is generally applied to the situation that the ground is fixed and the temperature is normal temperature.
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 ultrasonic sensor is not provided with a floater tracking the liquid level. The measuring cylinder is vertically arranged at the bottom of the measured liquid in use, and the liquid level is measured by utilizing the time difference of the ultrasonic wave emitted from the bottom of the liquid to the liquid level surface for reflection. The scheme is generally used for measuring the aviation kerosene liquid level (the freezing point temperature is lower than-55 ℃) on a passenger plane with low maneuverability, and the precision is higher. But still have limitations for some special applications. For example, vehicles with strong maneuverability and widely varying attitudes, the reflected wave reflection path will deviate from the defined measurement line because the liquid surface is not perpendicular to the measurement line, resulting in large measurement error and even failure.
3. The ultrasonic sensor is arranged at the bottom in the measuring cylinder, and a floater for tracking the liquid level is arranged in the measuring cylinder. The float geometry is cylindrical. The guide of the floater adopts a steel wire, an inner cylindrical surface or an outer cylindrical surface. The lower end surface of the cylindrical floater is used for reflecting ultrasonic waves during measurement. The normal line of the end face of the float of the structure can be always aligned with the end face of the ultrasonic conversion ring (14), namely, the measuring path through which the ultrasonic wave passes is not influenced by the posture of the container, the acceleration and the liquid fluctuation and is kept on a defined measuring line. But accuracy and stability as well as reliability are to be improved. The reason is that when the floater tracks the liquid level, the floater 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 a measuring result is large and even the floater fails.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an anti-inclination and anti-fluctuation ultrasonic liquid level sensor system and an operation method thereof.
The specific implementation content of the invention is as follows:
the invention provides an anti-inclination 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 the measured liquid in the liquid container, and comprises a waveguide tube vertically arranged in the liquid container, wherein the bottom of the waveguide tube is provided with a protective base; the bottom of the waveguide tube is provided with a protective base, and a measurement piezoelectric sheet which is arranged in the waveguide tube and sends ultrasonic waves upwards is arranged on the protective base; a through hole is formed in the bottom side of the waveguide tube, and the liquid to be measured flows between the liquid container and the waveguide tube through the through hole;
a floating ball floating on the liquid level surface of the liquid to be measured is arranged in the waveguide above the piezoelectric piece;
the waveguide tube is provided with a temperature measuring and junction box, and the temperature measuring and junction box is connected with a measuring piezoelectric sheet 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 control amplifying circuit, a high-speed AD conversion circuit, a high-speed data stream storage circuit, a single chip microcomputer module and a communication module which are sequentially connected; the precise program control 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 implement the present invention, further, the wall thickness of the waveguide is half of the propagation wavelength of the sound wave in the waveguide.
In order to better implement the invention, further, the waveguide comprises a matching layer, wherein the matching layer is arranged in the waveguide at the upper position of the piezoelectric measuring sheet;
defining the characteristic impedance of the piezoelectric sheet to be measured as Z1The characteristic impedance of the matching layer is Z2The characteristic impedance of the measured liquid is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet to the measured liquid is T, and the wavelength of the sound wave in the matching layer is lambda2The thickness of the matching layer is d1；
The characteristic impedance of the matching layer satisfies
Thickness of matching layer
Wherein n is a positive integer; the transmission coefficient T is 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-inclination 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, the ultrasonic liquid level sensor system comprises a waveguide tube vertically arranged in the liquid container, and the bottom of the waveguide tube is provided with a protective base; the bottom of the waveguide tube is provided with a protective base, and a measurement piezoelectric sheet which is arranged in the waveguide tube and sends ultrasonic waves upwards is arranged on the protective base; a through hole is formed in the bottom side of the waveguide tube, and the liquid to be measured flows between the liquid container and the waveguide tube through the through hole;
a floating ball floating on the liquid level surface of the liquid to be measured is arranged in the waveguide above the piezoelectric piece;
the waveguide tube is provided with a temperature measuring and junction box, and the temperature measuring and junction box is connected with a measuring piezoelectric sheet 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-testing module, a buffering module, an excitation module, an ultrasonic sensor, an amplitude limiting and pre-amplifying module, a gain band-pass filtering module, a primary program control amplifying module, a secondary program control amplifying module, a low-pass filtering module, an AD module and a single chip microcomputer;
the voltage stabilizing module, the temperature acquisition module, the 422 communication module, the active clock, the self-test module, the buffer module and the excitation module are respectively connected with the single chip microcomputer;
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 first-level program-controlled amplifying module, the second-level program-controlled amplifying module, the low-pass filtering module, the AD module and the cache module.
In order to better implement the present invention, further, the wall thickness of the waveguide is half of the propagation wavelength of the sound wave in the waveguide.
In order to better realize the invention, the invention further comprises a protective base and a sealing cover; the sealing cover is arranged at the top end of the waveguide tube and is hermetically connected with the top end of the interior of the liquid container;
the protection base is of a cylindrical structure with an opening at the upper end, the bottom end of the protection base is hermetically connected with the bottom end of the interior 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 back sheet, measure the piezoelectric patch setting and just be located the top of back sheet at the bottom of waveguide tube.
In order to better realize the invention, further, the backing layer is a mixture of spherical tungsten powder and epoxy resin, and steel balls are 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.
In order to better implement the invention, further, the waveguide comprises a matching layer, wherein the matching layer is arranged in the waveguide at the upper position of the piezoelectric measuring sheet;
defining the characteristic impedance of the piezoelectric sheet to be measured as Z1The characteristic impedance of the matching layer is Z2The characteristic impedance of the measured liquid is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet to the measured liquid is T, and the wavelength of the sound wave in the matching layer is lambda2The thickness of the matching layer is d1；
The characteristic impedance of the matching layer satisfies
Thickness of matching layer
Wherein n is a positive integer; the transmission coefficient T is 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-inclination and anti-fluctuation ultrasonic liquid level sensor system, and based on the anti-inclination and anti-fluctuation ultrasonic liquid level sensor system, the operation method specifically comprises the following steps:
step 1: initializing parameters;
step 2: running a test program;
and step 3: performing self-test and outputting a self-test result, wherein the self-test result comprises three conditions: outputting a test mark, having error self-test result and correct self-test result; when the self-test result is wrong, the test result is fed back to exceed the standard, the test parameters are reset, and the test is carried out again;
and 4, step 4: when the self-testing result is correct, a self-gain judgment flow is carried out;
and 5: when the self-gain is judged to be improper, starting a self-gain algorithm and judging again;
step 6: when the self-gain is judged to be proper in gain, identifying the high and low liquid level areas, dividing the identification result into the low liquid level area and the high liquid level area, and then correspondingly setting parameters of the low liquid level area or the high liquid level area;
and 7: triggering an excitation signal after the parameter setting of the low liquid level area or the parameter setting of the high liquid level area is carried out;
and 8: excitation and data sampling are carried out;
and step 9: carrying out 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 step 8 and the step 9 for multiple times, performing waveform superposition processing on the processed sampling data obtained multiple 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 processing;
step 12: after the operation of mean recursive filtering and Kalman filtering, respectively carrying out slope method characteristic point identification and correlation algorithm characteristic point identification; then, feature point judgment is carried out on feature points identified by the slope method feature point identification and the related algorithm feature point identification;
step 13: and 6, respectively carrying out the following operations according to the identification of the high liquid level area and the low liquid level area:
processing the 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: performing sound velocity correction on the ultrasonic sampling data processed by adopting an arithmetic progression method by combining a temperature signal;
performing sound velocity correction on the sampled data of the ultrasonic waves processed by adopting a ranking method by combining ultrasonic signals reflected by the standard block and temperature signals;
step 15: carrying out liquid level judgment on 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;
and step 17: performing Kalman filtering and continuity judgment on the measurement result of the liquid level value, and judging the liquid level value judged to be unqualified in the continuity judgment as liquid level data in a large rolling posture, so as to be useless;
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 self-test is as follows:
respectively carrying out hardware self-testing and software self-testing after starting self-testing operation;
the hardware self-test comprises a power supply voltage test, an amplifier test and a sound wave measurement test; outputting a test identifier after the test is qualified;
the software self-test comprises an algorithm test, and a test identifier is output after the test is qualified.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) compared with the traditional cylindrical steel wire floater, the spherical floater does not have clamping stagnation between guide rails, reduces friction, and can be compatible with various inclination angles and acceleration fluctuation;
(2) in order to enable the sound wave of the piston sound source to radiate into a medium with larger transmissivity, a matching layer technology is adopted at the piston sound source, in order to reduce the intensity of a reflected wave sound field, the sound wave is enabled to be transmitted out of the pipe wall at the pipe wall as far as possible and then to radiate outside the circular pipe, and the amplitude of part of sound wave in a high-order mode is reduced by adopting the circular pipe sound transmission window principle;
(3) the addition of the backing layer reduces the influence of 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 structural 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 view of a schematic flow diagram of a method of operation;
FIG. 4 is a schematic view of a subsequent portion of the process flow diagram of the method of operation of FIG. 3;
FIG. 5 is a schematic view of a subsequent portion of the operational method flow diagram of FIGS. 3 and 4;
FIG. 6 is a schematic view of a subsequent portion of the operational method flow diagram of FIGS. 3, 4 and 5;
FIG. 7 is a flow chart of a self-test;
FIG. 8 is a schematic view of a sensor of the present invention installed in a liquid container;
FIG. 9 is a schematic diagram of a specific structure of the sensor;
FIG. 10 is a schematic view of a perpendicular incidence dielectric interface of a measurement piezoelectric patch, a matching layer, and a fluid under test;
FIG. 11 is a schematic view of the interface of the liquid being measured and the waveguide;
FIG. 12 is a schematic view of a sound field of a round tube sound-transmitting window according to the present invention;
FIG. 13 is a schematic diagram of the acoustic field in the waveguide from the transmission of the ultrasonic waves to the return of the reflected waves according to the present invention;
FIG. 14 is a schematic diagram of waveforms of ultrasonic signals;
FIG. 15 is a schematic view showing the measurement state of the floating ball with and without inclination;
FIG. 16 is a diagram of raw echoes;
FIG. 17 is a schematic diagram of a signal wave after being processed by a software algorithm;
FIG. 18 is a waveform diagram of a complete original signal wave;
FIG. 19 is a schematic diagram of a waveform identified by feature location;
FIG. 20 is a waveform schematic of a high level waveform;
FIG. 21 is a schematic view of a low level waveform undergoing an arithmetic series process;
fig. 22 is a waveform diagram illustrating an echo after being subjected to a ranking method.
Wherein: 1. the liquid container, 2, waveguide tube, 3, protective base, 4, calibration cylinder, 5, calibration piezoelectric plate, 6, calibration reflection block, 7, measurement piezoelectric plate, 8, measured liquid, 9, liquid level, 10, floating ball, 11, sealing cover, 12, back lining layer, 13, matching layer, 14, conversion ring, 15, anti-collision metal net, 16, side silicon rubber ring, 17, bottom silicon rubber ring, 18, reference block, 19, temperature measurement and junction box, 20, standard block, A, main wave, B, reference block reflection wave, C, high-order wave.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and therefore should not be considered as a limitation to the scope of protection. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, 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; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1:
the embodiment provides an anti-inclination and anti-fluctuation ultrasonic liquid level sensor system, as shown in fig. 1, which is installed in a liquid container 1, connected with a signal processing system, and used for measuring a measured liquid 8 in the liquid container 1, wherein the ultrasonic liquid level sensor system comprises a waveguide tube 2 vertically arranged in the liquid container 1, and a protective base 3 is arranged at the bottom of the waveguide tube 2; 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 sends ultrasonic upwards is arranged on the protective base 3; a through hole is formed in the bottom side of the waveguide tube 2, and the liquid to be detected 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 piezoelectric measuring 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 sheet 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 control amplifying circuit, a high-speed AD conversion circuit, a high-speed data stream storage circuit, a single chip microcomputer module and a communication module which are sequentially connected; the precise program control amplifying circuit is also connected with the singlechip module; the excitation and reception 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 half of the wavelength of the sound wave propagating in the waveguide 2.
In order to better implement the invention, the waveguide tube further comprises a matching layer 13, wherein the matching layer 13 is arranged in the waveguide tube 2 at a position above the measuring piezoelectric sheet 7;
the characteristic impedance of the piezoelectric sheet 7 is defined as Z1Characteristic resistance of the matching layer 13Is resistant to Z2The characteristic impedance of the measured liquid 8 is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet 7 to the measured liquid 8 is T, and the wavelength of the sound wave in the matching layer 13 is lambda2The thickness of the matching layer 13 is d1；
The characteristic impedance of the matching layer 13 satisfies
Thickness of the matching layer 13
Wherein n is a positive integer; the transmission coefficient T is 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-inclination and anti-fluctuation ultrasonic liquid level sensor system, as shown in fig. 2, which is installed in a liquid container 1, connected with a signal processing system, and used for measuring a measured liquid 8 in the liquid container 1, wherein the ultrasonic liquid level sensor system comprises a waveguide tube 2 vertically arranged in the liquid container 1, and a protective base 3 is arranged at the bottom of the waveguide tube 2; 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 sends ultrasonic upwards is arranged on the protective base 3; a through hole is formed in the bottom side of the waveguide tube 2, and the liquid to be detected 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 piezoelectric measuring 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 sheet 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-testing module, a buffering module, an excitation module, an ultrasonic sensor, an amplitude limiting and pre-amplifying module, a gain band-pass filtering module, a primary program control amplifying module, a secondary program control amplifying module, a low-pass filtering module, an AD module and a single chip microcomputer;
the voltage stabilizing module, the temperature acquisition module, the 422 communication module, the active clock, the self-test module, the buffer module and the excitation module are respectively connected with the single chip microcomputer;
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 first-level program-controlled amplifying module, the second-level program-controlled amplifying module, the low-pass filtering module, the AD module and the cache module.
In order to better implement the present invention, further, the wall thickness of the waveguide 2 is half of the wavelength of the sound wave propagating in the waveguide 2.
In order to better implement the invention, the invention further comprises a protective base 3 and a sealing cover 11; the sealing cover 11 is arranged at the top end of the waveguide tube 2 and is hermetically connected with the top end inside the liquid container 1;
the protection base 3 is a cylindrical structure with an opening at the upper end, the bottom end of the protection base 3 is hermetically connected with the bottom end of the interior 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;
and 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 tube 2 and is positioned above the backing layer 12.
In order to better implement the present 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 spherical tungsten powder and epoxy resin; the diameter of the steel ball is between 0.3mm and 0.7 mm.
In order to better implement the invention, the waveguide tube further comprises a matching layer 13, wherein the matching layer 13 is arranged in the waveguide tube 2 at a position above the measuring piezoelectric sheet 7;
the characteristic impedance of the piezoelectric sheet 7 is defined as Z1The characteristic impedance of the matching layer 13 is Z2The characteristic impedance of the measured liquid 8 is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet 7 to the measured liquid 8 is T, and the wavelength of the sound wave in the matching layer 13 is lambda2The thickness of the matching layer 13 is d1；
The characteristic impedance of the matching layer 13 satisfies
Thickness of the matching layer 13
Wherein n is a positive integer; the transmission coefficient T is 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 parts of this embodiment are the same as those of embodiment 1, and thus are not described again.
Example 3:
the present embodiment is based on the above embodiment 2, as shown in fig. 3, fig. 4, fig. 5, fig. 6, and fig. 7, wherein fig. 3, fig. 4, fig. 5, and fig. 6 sequentially form a complete flow diagram, which is divided into four parts due to the overlong space; the operation method of the anti-inclination and anti-fluctuation ultrasonic liquid level sensor system is further provided, and based on the anti-inclination and anti-fluctuation ultrasonic liquid level sensor system, the operation method specifically comprises the following steps:
step 1: initializing parameters;
step 2: running a test program;
and step 3: performing self-test and outputting a self-test result, wherein the self-test result comprises three conditions: outputting a test mark, having error self-test result and correct self-test result; when the self-test result is wrong, the test result is fed back to exceed the standard, the test parameters are reset, and the test is carried out again;
and 4, step 4: when the self-testing result is correct, a self-gain judgment flow is carried out;
and 5: when the self-gain is judged to be improper, starting a self-gain algorithm and judging again;
step 6: when the self-gain is judged to be proper in gain, identifying the high and low liquid level areas, dividing the identification result into the low liquid level area and the high liquid level area, and then correspondingly setting parameters of the low liquid level area or the high liquid level area;
and 7: triggering an excitation signal after the parameter setting of the low liquid level area or the parameter setting of the high liquid level area is carried out;
and 8: excitation and data sampling are carried out;
and step 9: carrying out 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 step 8 and the step 9 for multiple times, performing waveform superposition processing on the processed sampling data obtained multiple 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 processing;
step 12: after the operation of mean recursive filtering and Kalman filtering, respectively carrying out slope method characteristic point identification and correlation algorithm characteristic point identification; then, feature point judgment is carried out on feature points identified by the slope method feature point identification and the related algorithm feature point identification;
step 13: and 6, respectively carrying out the following operations according to the identification of the high liquid level area and the low liquid level area:
processing the 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: performing sound velocity correction on the ultrasonic sampling data processed by adopting an arithmetic progression method by combining a temperature signal;
performing sound velocity correction on the sampled data of the ultrasonic waves processed by adopting a ranking method by combining ultrasonic signals reflected by the standard block and temperature signals;
step 15: carrying out liquid level judgment on 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;
and step 17: performing Kalman filtering and continuity judgment on the measurement result of the liquid level value, and judging the liquid level value judged to be unqualified in the continuity judgment as liquid level data in a large rolling posture, so as to be useless;
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 self-test is as follows:
respectively carrying out hardware self-testing and software self-testing after starting self-testing operation;
the hardware self-test comprises a power supply voltage test, an amplifier test and a sound wave measurement test; outputting a test identifier after the test is qualified;
the software self-test comprises an algorithm test, and a test identifier is output after the test is qualified.
The working principle is as follows: as shown in fig. 16, the original echo signal of the sensor is filtered recursively, the signal is half-wave detected after being subjected to median filtering and denoising, and finally the waveform is subjected to albert envelope to obtain the wave packet of the signal shown in fig. 17. Fig. 18 is a diagram of the entire original waveform, and fig. 19 is a diagram of the signal envelope waveform after the above-described processing method. The characteristics of the signal wave packet in the high liquid level area show a single wave as shown in fig. 20, and the signal sequencing concludes that the farthest 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 except for the leftmost excitation wave, there are two or more echo wave packets, and at this time, an arithmetic progression method should be applied, and the wave packets are distributed in an arithmetic progression, that is, the positions of the wave packets are in an arithmetic progression to find the sound wave whose characteristic position is the first one to return to the transducer. As shown in fig. 22, when the sensor introduces the reference ring or the floating ball to the bottom of the sensor, it is necessary to use a ranking method to rank the reference ring or the floating ball according to the position of the wave packet, and the sequence is the reference ring wave floating ball wave and the higher order wave that may occur, and the higher order wave amplitude is smaller than the floating ball wave and can be distinguished by ranking the amplitude. In conclusion, the liquid level signal is obtained according to various algorithms and methods, and finally liquid level height data is obtained. Table 1 shows the measured values for different angles of inclination of the page, and it can be seen that the sensor is fully functional for inclinations in the range 0 to 60 degrees. The results of vertical static accuracy experiments shown in table 2 show that the sensor has high accuracy in measuring the height of the liquid level, and has important popularization value.
Table 1 anti-tilt test data
TABLE 2 static vertical accuracy test
Other parts of this embodiment are the same as any of embodiments 1-2 described above, and thus are not described again.
Example 4:
the embodiment also provides an anti-inclination and anti-fluctuation ultrasonic liquid level sensor, which is installed in the liquid container 1 and connected with the signal processing system, as shown in fig. 8 and 9, the ultrasonic liquid level sensor comprises a waveguide tube 2 vertically installed in the liquid container 1, and the upper end and the lower end of the waveguide tube are respectively connected with the upper end and the lower end inside the liquid container 1; the thickness of the tube wall of the waveguide tube 2 is half of the transmission 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 filled with a measured liquid 8, and a plurality of guide holes for enabling the measured liquid 8 to flow between the liquid container 1 and the waveguide tube 2 are circumferentially arranged on the waveguide tube 2;
a measuring piezoelectric sheet 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 sheet 7, and a floating ball 10 floating along with the liquid level surface 9 of the measured liquid 8 is arranged above the measuring piezoelectric sheet 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 flow guide holes for enabling the liquid 8 to be measured to flow 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 patch 10 connected with a signal processing system and a calibration block matched with the calibration piezoelectric patch 10.
The working principle is as follows: firstly, an excitation pulse is sent to a calibration piezoelectric sheet 5 in a calibration cylinder 4 through a signal processing system, so that the calibration piezoelectric sheet 5 is excited to emit ultrasonic vibration;
secondly, when the ultrasonic wave emitted by the calibration piezoelectric sheet 5 is transmitted to the standard reflection block 6, a reflected wave is generated, and the ultrasonic wave crossing time t of the calibration piezoelectric sheet 5 and the standard reflection block 6 is obtained according to the ultrasonic wave principle0A fixed distance L between the known calibration piezo-electric strip 5 and the standard reflector block 60On the basis, the real-time sound velocity V is obtained according to a velocity-time distance formula;
then, an excitation pulse is sent to the measurement piezoelectric patch 7 in the waveguide 2 through a signal processing system, so that the measurement piezoelectric patch 7 is excited to emit ultrasonic vibration;
then, when the ultrasonic wave emitted by the measurement piezoelectric plate 7 is transmitted to the lower surface of the floating ball 10, a reflected wave reflected back to the measurement piezoelectric plate 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:
in this embodiment, as shown in fig. 9, the protection base 3 and the sealing cover 11 are further included on the basis of the above embodiment 4; the sealing cover 11 is arranged at the top end of the waveguide tube 2 and is hermetically connected with the top end inside the liquid container 1; the protection base 3 is a cylindrical structure with an opening at the upper end, the bottom end of the protection base 3 is hermetically connected with the bottom end of the interior 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; and 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 tube 2 and is positioned 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.
The working principle is as follows: the backing layer 12 is added to reduce the effect of the bottom echo on the excitation and the interference of the bottom clutter on the measurement signal.
The other parts of this embodiment are the same as those of embodiment 4, and thus are not described again.
Example 6:
in this embodiment, on the basis of the above embodiments 4 to 5, in order to better implement the present invention, as shown in fig. 9, the present invention further includes a side silicone rubber ring 16 and a bottom silicone rubber ring 17; the lateral silicone rubber ring 16 is arranged in the protective base 3 and positioned at the outer side of the back lining layer 12; the bottom silicone rubber ring 17 is disposed within the protective base 3 at the bottom of the backing layer 12.
Other parts of this embodiment are the same as any of embodiments 4 to 5, and thus are not described again.
Example 7:
this embodiment is based on any of embodiments 4 to 6, and 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 piezoelectric patch 7;
the characteristic impedance of the piezoelectric sheet 7 is defined as Z1The characteristic impedance of the matching layer 13 is Z2The characteristic impedance of the measured liquid 8 is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet 7 to the measured liquid 8 is T, and the wavelength of the sound wave in the matching layer 13 is lambda2The thickness of the matching layer 13 is d1；
The characteristic impedance of the matching layer 13 satisfies
Thickness of the matching layer 13
Wherein n is a positive integer; the transmission coefficient T is 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 working principle is as follows: in order to enable sound waves emitted by a piston sound source, namely the measurement piezoelectric sheet 7 to radiate into a medium with high transmissivity, a matching layer technology is adopted at the position of the piston sound source, namely the measurement piezoelectric sheet 7, in order to reduce the intensity of a reflected wave sound field, the sound waves are enabled to be transmitted out of the tube wall of the waveguide tube 2 as far as possible to radiate to the outside of the waveguide tube 2, and the amplitude of part of sound waves in a high-order mode is reduced by adopting a circular tube sound transmission window principle.
As shown in FIG. 10, the characteristic impedance of the piezoelectric sheet 7 was measured as Z in consideration of the case where the interface with the medium was perpendicularly incident1The characteristic impedance of the matching layer 13 is Z2The thickness of the matching layer 13 is d1The characteristic impedance of the measured liquid 8 is Z3. The transmission coefficient of the sound intensity transmitted into the measured liquid 8 by the measurement piezoelectric sheet 7 is T, that is:
when matching layer 13Has a characteristic impedance of
And thickness
Where is λ2Is the wavelength of the acoustic wave in the matching layer 13, N ∈ N), and the transmission coefficient T is 1. The matching layer technology is adopted to improve the energy coupling of the measurement piezoelectric sheet 7 into the measured liquid 8.
Similarly, as shown in FIG. 11, in the two-layer interface formed by the liquid 8 to be measured and the waveguide 2, the characteristic impedance of the waveguide 2 is Z4, and the wavelength of the acoustic wave in the waveguide 2 is λ4The thickness of the waveguide 2 is d2. When the thickness d of the waveguide 22In that
In the vicinity, the transmission coefficient of the acoustic wave radiated from the liquid 8 to be measured into the liquid medium through the waveguide is close to 1. At this time, the waveguide tube 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, therefore, a part of the sound wave 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, the sound field schematic diagram of the round tube sound-transparent window is shown, the liquid medium is water, the rigid floating ball is a 304 stainless steel floating ball, the waveguide tube is a carbon fiber composite round tube, the thickness of the tube wall is half of the wavelength and is approximately equal to 1.25mm, the matching layer is made of polytetrafluoroethylene, and the thickness of the matching layer is quarter of the wavelength and is approximately equal to 1 mm. The ultrasonic liquid level sensor not only reduces the energy of partial high-order mode waves and improves the signal-to-noise ratio, but also greatly lightens the mass compared with the traditional metal circular tube sensor, and makes the ultrasonic liquid level sensor light.
Other parts of this embodiment are the same as any of embodiments 4 to 6, and thus are not described again.
Example 8:
this embodiment is based on any one of embodiments 4 to 7, and further includes an anti-collision metal mesh 15, where the anti-collision metal mesh 15 is installed at the bottom of the waveguide 2 and located between the piezoelectric measuring sheet 7 and the floating ball 10. The working principle is as follows: the floating ball 10 is prevented from colliding with the measuring piezoelectric plate 7 by arranging the anti-collision metal net 15. Other parts of this embodiment are the same as any of embodiments 4 to 7, and thus are not 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 in a hollow spherical shape, the diameter of the floating ball is 35mm, the roundness error is ± 0.1mm, the surface of the floating ball is mirror-polished, and the thickness of the wall of the floating ball 10 is 0.3 mm; the waveguide tube 2 is a carbon fiber composite circular tube, the length of the tube is 1000mm, the inner diameter is 36mm, the outer diameter is 38.5mm, 3 phi 4 diversion holes are uniformly distributed at the bottom end and the middle end of the waveguide tube 2 in the circumferential direction, and a polyurethane wave-absorbing material with the thickness of 0.01mm is sprayed on the inner wall of the waveguide tube 2; the calibration cylinder 4 is made of carbon fiber composite materials, the cylinder length is 150mm, the inner diameter is 15mm, the outer diameter is 17mm, and 2 phi 3 diversion holes are uniformly distributed at the bottom end and the middle end of the calibration cylinder 4 in the circumferential direction; the protective base 3 is made of an aviation aluminum material; the frequency of the measuring piezoelectric sheet 7 and the calibration piezoelectric sheet 5 is 1MHz, the diameter phi is 35mm, the diameter phi is 15mm, and the piezoelectric coefficient is larger than 800 multiplied by 10-3C/N piezoelectric ceramics. Other parts of this embodiment are the same as any of embodiments 4 to 8, and thus are not described again.
Example 10:
in this embodiment, on the basis of any one of embodiments 4 to 9, taking the waveguide 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 measurement piezoelectric plate 7 emitting ultrasonic waves to the ultrasonic waves reflected back by the floating ball 10 in sequence from left to right, it can be seen that an ultrasonic main wave a is emitted from the measurement piezoelectric plate 7, a reference block 18 is disposed in the waveguide 2, the ultrasonic main wave a passes through a reference block reflected wave B reflected back by the reference block 18, and the ultrasonic main wave a passes through the floating ball 10 and is reflected back to the measurement piezoelectric plate 7 to bring back part of the high-order wave C. The pressure gauge for distinguishing the total sound field pressure is shown on the right side of FIG. 13, wherein the color corresponds to the corresponding sound field pressure value in the sound field schematic diagram, because of the limitation of the color of the drawing, the background of the waveguide 2 is green, and corresponds to-1 × 10 on the pressure gauge3Pa to 1X 103Pa, the colors of the main ultrasonic wave a, the reference block reflected wave B, and the higher order wave C in the waveguide 2 in different states are difficult to distinguish after being converted into black and white pictures, so the data format is described below the waveguide 2 in the corresponding state of fig. 13, although the distinguished colors are not shown in fig. 13,however, fig. 13 is a screenshot of test data, which does not substantially affect the technical solution described in the present application, and thus will be described. It should be noted that fig. 18, fig. 19, fig. 20, fig. 21, and fig. 22 are only computer interface screenshots, and the test interface of the instrument software is a black-white line, which is only shown as an experimental effect and does not have any substantial influence on the specific content of the present application, so the applicant requests to retain this form of effect graph display.
Other parts of this embodiment are the same as any of embodiments 1 to 6, and thus are not described again.
Example 11:
the embodiment provides an application method of an anti-inclination and anti-fluctuation ultrasonic liquid level sensor, which is based on the anti-inclination and anti-fluctuation ultrasonic liquid level sensor and is characterized by comprising the following steps:
firstly, an excitation pulse is sent to a calibration piezoelectric sheet 5 in a calibration cylinder 4 through a signal processing system, so that the calibration piezoelectric sheet 5 is excited to emit ultrasonic vibration;
secondly, when the ultrasonic wave emitted by the calibration piezoelectric sheet 5 is transmitted to the standard reflection block 6, a reflected wave is generated, and the ultrasonic wave crossing time t of the calibration piezoelectric sheet 5 and the standard reflection block 6 is obtained according to the ultrasonic wave principle0A fixed distance L between the known calibration piezo-electric strip 5 and the standard reflector block 60On the basis, the real-time sound velocity V is obtained according to a velocity-time distance formula;
then, an excitation pulse is sent to the measurement piezoelectric patch 7 in the waveguide 2 through a signal processing system, so that the measurement piezoelectric patch 7 is excited to emit ultrasonic vibration;
then, when the ultrasonic wave emitted by the measurement piezoelectric plate 7 is transmitted to the lower surface of the floating ball 10, a reflected wave reflected back to the measurement piezoelectric plate 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-inclination and anti-fluctuation ultrasonic liquid level sensor, which is used for performing ultrasonic calculation processing in an application method of the anti-inclination and anti-fluctuation ultrasonic liquid level sensor, and comprises the following steps:
firstly, enveloping an echo by adopting full-wave detection;
then, the position Pmax of the maximum correlation coefficient P is obtained by adopting an autocorrelation algorithm, wherein the size of a correlation algorithm window of the autocorrelation algorithm is half of the envelope width, namely the half width of the Gaussian narrow pulse;
then, obtaining the slope Ki of the curve corresponding to the half envelope width in the echo, setting a slope comparison value, and judging the slope Ki after obtaining the position Pmax with the maximum correlation coefficient P: and when the slope Ki is larger than the set slope comparison value, judging the position Pmax as the echo position, otherwise, not judging the position as the echo position.
Example 13:
in this embodiment, in order to further realize the present invention in an improved manner on the basis of embodiment 12 described above, a high liquid level region and a low liquid level region are set in the liquid container 1, and in the low liquid level region, there are a plurality of positions P (i) having close correlation coefficients and in an arithmetic progression, and the liquid level height is determined in the low liquid level region by calculating the time difference between the positions P (i) and P (i-1).
Other parts of this embodiment are the same as those of embodiment 12, and thus are not described again.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (10)
1. An ultrasonic liquid level sensor system resisting inclination and fluctuation is arranged in a liquid container (1), is connected with a signal processing system and is used for measuring a measured liquid (8) in the liquid container (1), and is characterized by comprising a waveguide tube (2) vertically arranged in the liquid container (1), wherein the bottom of the waveguide tube (2) is provided with a protective base (3); 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 sends ultrasonic upwards is arranged on the protective base (3); a through hole is formed in the bottom side of the waveguide tube (2), and the liquid (8) to be measured 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 liquid to be measured (8) is arranged at a position above the 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 the measuring piezoelectric sheet 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 control amplifying circuit, a high-speed AD conversion circuit, a high-speed data stream storage circuit, a single chip microcomputer module and a communication module which are sequentially connected; the precise program control amplifying circuit is also connected with the singlechip module; the excitation and reception circuit is connected to the temperature measuring and junction box (19).
2. An ultrasonic level sensor system resistant to tilting and waving according to claim 1, characterized in that the wall thickness of the waveguide (2) is half the wavelength of the sound waves propagating in the waveguide (2).
3. An ultrasonic level sensor system resistant to tilting and wave motion according to claim 1, further comprising a matching layer (13), said matching layer (13) being arranged within said waveguide (2) at a position above the measurement piezoelectric patch (7);
defining the characteristic impedance of the piezoelectric sheet (7) to be measured as Z1The characteristic impedance of the matching layer (13) is Z2The characteristic impedance of the measured liquid (8) is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet (7) to the measured liquid (8) is T, and the wavelength of the sound wave in the matching layer (13) is lambda2The thickness of the matching layer (13) is d1；
The characteristic impedance of the matching layer (13) satisfies
Thickness of the matching layer (13)
Wherein n is a positive integer; the transmission coefficient T is 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.
4. An ultrasonic liquid level sensor system resisting inclination and fluctuation is arranged in a liquid container (1), is connected with a signal processing system and is used for measuring a measured liquid (8) in the liquid container (1), and is characterized by comprising a waveguide tube (2) vertically arranged in the liquid container (1), wherein the bottom of the waveguide tube (2) is provided with a protective base (3); 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 sends ultrasonic upwards is arranged on the protective base (3); a through hole is formed in the bottom side of the waveguide tube (2), and the liquid (8) to be measured 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 liquid to be measured (8) is arranged at a position above the 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 the measuring piezoelectric sheet 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-testing module, a buffering module, an excitation module, an ultrasonic sensor, an amplitude limiting and pre-amplifying module, a gain band-pass filtering module, a primary program control amplifying module, a secondary program control amplifying module, a low-pass filtering module, an AD module and a single chip microcomputer;
the voltage stabilizing module, the temperature acquisition module, the 422 communication module, the active clock, the self-test module, the buffer module and the excitation module are respectively connected with the single chip microcomputer;
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 first-level program-controlled amplifying module, the second-level program-controlled amplifying module, the low-pass filtering module, the AD module and the cache module.
5. An ultrasonic level sensor system resistant to tilting and waves as claimed in claim 4, characterized in that the wall thickness of the waveguide (2) is half the wavelength at which sound waves propagate in the waveguide (2).
6. An ultrasonic level sensor system resistant to tilting and waves as claimed in claim 4, characterized by further comprising a protective base (3) and a flap (11); the sealing cover (11) is arranged at the top end of the waveguide tube (2) and is hermetically connected 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 hermetically connected with the bottom end of the interior 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);
and 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 tube (2) and is positioned above the backing layer (12).
7. The ultrasonic level sensor system of claim 6, wherein the backing layer (12) is a mixture of spherical tungsten powder and epoxy resin, and the mixture of spherical tungsten powder and epoxy resin is also uniformly doped with steel balls; the diameter of the steel ball is between 0.3mm and 0.7 mm.
8. An ultrasonic level sensor system resistant to tilting and waves as claimed in claim 4, characterized by further comprising a matching layer (13), said matching layer (13) being arranged within said waveguide (2) at a position above the measurement piezoelectric patch (7);
defining the characteristic impedance of the piezoelectric sheet (7) to be measured as Z1The characteristic impedance of the matching layer (13) is Z2The characteristic impedance of the measured liquid (8) is Z3The transmission coefficient of the sound intensity transmitted from the measurement piezoelectric sheet (7) to the measured liquid (8) is T, and the wavelength of the sound wave in the matching layer (13) is lambda2The thickness of the matching layer (13) is d1；
The characteristic impedance of the matching layer (13) satisfies
Thickness of the matching layer (13)
Wherein n is a positive integer; the transmission coefficient T is 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.
9. A method of operating a tilt and wave resistant ultrasonic level sensor system, based on the tilt and wave resistant ultrasonic level sensor system of claim 4, comprising the steps of:
step 1: initializing parameters;
step 2: running a test program;
and step 3: performing self-test and outputting a self-test result, wherein the self-test result comprises three conditions: outputting a test mark, having error self-test result and correct self-test result; when the self-test result is wrong, the test result is fed back to exceed the standard, the test parameters are reset, and the test is carried out again;
and 4, step 4: when the self-testing result is correct, a self-gain judgment flow is carried out;
and 5: when the self-gain is judged to be improper, starting a self-gain algorithm and judging again;
step 6: when the self-gain is judged to be proper in gain, identifying the high and low liquid level areas, dividing the identification result into the low liquid level area and the high liquid level area, and then correspondingly setting parameters of the low liquid level area or the high liquid level area;
and 7: triggering an excitation signal after the parameter setting of the low liquid level area or the parameter setting of the high liquid level area is carried out;
and 8: excitation and data sampling are carried out;
and step 9: carrying out 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 step 8 and the step 9 for multiple times, performing waveform superposition processing on the processed sampling data obtained multiple 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 processing;
step 12: after the operation of mean recursive filtering and Kalman filtering, respectively carrying out slope method characteristic point identification and correlation algorithm characteristic point identification; then, feature point judgment is carried out on feature points identified by the slope method feature point identification and the related algorithm feature point identification;
step 13: and 6, respectively carrying out the following operations according to the identification of the high liquid level area and the low liquid level area:
processing the 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: performing sound velocity correction on the ultrasonic sampling data processed by adopting an arithmetic progression method by combining a temperature signal;
performing sound velocity correction on the sampled data of the ultrasonic waves processed by adopting a ranking method by combining ultrasonic signals reflected by the standard block and temperature signals;
step 15: carrying out liquid level judgment on 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;
and step 17: performing Kalman filtering and continuity judgment on the measurement result of the liquid level value, and judging the liquid level value judged to be unqualified in the continuity judgment as liquid level data in a large rolling posture, so as to be useless;
step 18: and outputting the data with the continuity judged to be qualified as the tested liquid level height data.
10. The method of operating a tilt and wave resistant ultrasonic level sensor system of claim 9, wherein step 3: the specific operation of self-test is as follows:
respectively carrying out hardware self-testing and software self-testing after starting self-testing operation;
the hardware self-test comprises a power supply voltage test, an amplifier test and a sound wave measurement test; outputting a test identifier after the test is qualified;
the software self-test comprises an 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 true CN114046858A (en) | 2022-02-15 |
| CN114046858B 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) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119197703A (en) * | 2024-09-14 | 2024-12-27 | 四川泛华航空仪表电器有限公司 | A method, system, device and medium for measuring airborne fuel level |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7421895B1 (en) * | 2005-04-21 | 2008-09-09 | Caldwell Joseph W | Fluid level measuring system |
| CN101634580A (en) * | 2009-08-28 | 2010-01-27 | 四川大学 | Ultrasonic liquid level measuring sensor capable of resisting inclination and fluctuation |
| JP2011002326A (en) * | 2009-06-18 | 2011-01-06 | Ricoh Elemex Corp | Ultrasonic liquid level meter |
| 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 |
| 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 |
| 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 |
| 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 (7)
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
Non-Patent Citations (1)
| Title |
|---|
| 上官明禹: "超声波液位计的原理与应用", 《机电信息》, 31 December 2010 (2010-12-31), pages 12 - 14 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119197703A (en) * | 2024-09-14 | 2024-12-27 | 四川泛华航空仪表电器有限公司 | A method, system, device and medium for measuring airborne fuel level |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114046858B (en) | 2024-08-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1123946A (en) | Ultrasonic transducer with reference reflector | |
| US6584860B1 (en) | Flow probe insertion gauge | |
| CN114046857A (en) | Anti-inclination and anti-fluctuation ultrasonic liquid level sensor and application and processing method thereof | |
| CN110208384A (en) | A kind of workpiece surface is open the measurement method at oblique flaw height and inclination angle | |
| CN110160622A (en) | A kind of travelling-wave tubes hydrophone sensitivity consistency on-line calibration method | |
| CN103454643B (en) | Method for accurately measuring constant sound pressure FSK ultrasonic wave transition time | |
| CN209689617U (en) | A kind of dual probe water-depth measurement device | |
| JP2005010159A (en) | Method and apparatus for measuring the thickness of a part having an outer coating using an impedance matching delay line | |
| CN114046858A (en) | Anti-inclination and anti-fluctuation ultrasonic liquid level sensor system and operation method thereof | |
| CN206670732U (en) | A kind of fluid level measuring instrument based on ultrasonic wave | |
| CN109341819A (en) | Self-correction ultrasonic measuring device and its measurement method | |
| CN209197860U (en) | Self-correction ultrasonic measuring device | |
| US4038629A (en) | Propagation delay meter | |
| CN114384525B (en) | A target intensity self-test method and self-test system based on boundary sound reflection | |
| CN104501909A (en) | Liquid level measuring device and measuring method for small measuring range based on supersonic | |
| CN115389069A (en) | Plane stress detection device and detection method | |
| Olmos | Extending the accuracy of ultrasonic level meters | |
| KR20090040699A (en) | Measurement range extension device for ultrasonic thickness gauge | |
| Patterson | Using the Ocean Surface as a Reflector for a Self‐Reciprocity Calibration of a Transducer | |
| Grekov et al. | Development of in situ acoustic instruments for the aquatic environment study | |
| CN205506170U (en) | Radar detection of water level system | |
| US7421901B2 (en) | Method of using ultrasound to inspect a part in immersion | |
| Isaev et al. | Reduction of the error of hydrophone calibration with respect to the field in a hydroacoustic tank by the reciprocity method | |
| RU2692409C1 (en) | Method of measuring liquid level | |
| RU2804343C1 (en) | Method for measuring the speed of underwater currents |
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 |