CN203100824U - Level measurement device based on standing sound wave method and audio card - Google Patents
Level measurement device based on standing sound wave method and audio card Download PDFInfo
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- CN203100824U CN203100824U CN 201220707051 CN201220707051U CN203100824U CN 203100824 U CN203100824 U CN 203100824U CN 201220707051 CN201220707051 CN 201220707051 CN 201220707051 U CN201220707051 U CN 201220707051U CN 203100824 U CN203100824 U CN 203100824U
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Abstract
The utility model relates to a level measurement device based on a standing sound wave method and an audio card. The level measurement device comprises an acoustic guide tube, an acoustic wave generation unit, an acoustic wave receiving unit, and an acoustic signal A/D (analog/digital) acquisition and D/A (digital/analog) conversion unit. The acoustic wave generation unit is a loudspeaker. The acoustic wave receiving unit is a microphone. The acoustic signal A/D acquisition and D/A conversion unit is an audio card for home computers. A wedge piston is disposed on the upper portion of the acoustic guide tube. The loudspeaker and the microphone are packaged in the wedge piston and can be separated from the acoustic guide tube. Compared with the prior art, the level measurement device has the advantages that measurement results are accurate, the signal transmitter and the signal receiver can be disposed at the same end of the acoustic guide tube to facilitate single-end measurement, the level measurement device is suitable for actual operating environments, the whole system hardware is low in cost, and the level measurement device is widely applicable to level measurement for liquid tanks and also widely applicable to demonstrations for standing sound wave experiments in college physics.
Description
Technical field
The utility model belongs to and utilizes acoustic method measuring liquid level technical field, relates to a kind of liquid level emasuring device based on sound standing wave method and sound card.
Background technology
Level measuring method has a lot, and wherein ultrasonic measuring liquid level is one of most popular method, and its measuring principle is to the fixing ultrasound wave of liquid level transmission frequency and receives echo, multiply by the distance of the Time Calculation liquid level of roundtrip to ultrasonic probe, ultrasonic receiver with the velocity of sound.But precision is limited easily affected by environment.In the Experiment of College Physics course, an experiment that utilizes the standing wave measurement ultrasonic propagation velocity is arranged, measurement at that time need be known the distance of two resonance hard point.Utilize the standing wave method measuring distance, generally adopt the method for ultrasonic measurement mistiming, the common more complicated of this method.This experiment can provide a new thinking, and that is exactly to utilize standing wave to remove measuring distance under the prerequisite of the velocity of propagation of known sound wave.In fact, level measuring method based on the sound standing wave principle has obtained widespread use in many industrial circles (as wastewater treatment, chemical industry, petroleum industry), ultrasonic wave measuring method wherein, with characteristics such as its good directionality, easy operatings, become one of the most frequently used method, its measuring principle is to the fixing ultrasound wave of liquid level transmission frequency and receives echo, multiply by the Time Calculation liquid level that the comes and goes range distance to the sound wave receiving trap with the velocity of sound.But, hyperacoustic emission is not easy to realize with acceptance, is there there better method? can find by analysis, if utilize the audio frequency sound of frequency change, by measuring adjacent resonant frequency of standing wave and equal difference thereof relation, just liquid level can be calculated, and the precision of measurement can be improved.
In the prior art before the present invention, CN200410062355 patent " a kind of sound wave liquid level emasuring device and method thereof " provides a kind of method with heard sound signal measurement liquid level, this method is " by forming standing wave; note the amplitude of the sound of a certain frequency at reference point; also sound amplitude and the preceding frequency sound amplitude that is once write down with this frequency compares; find out the minimum amplitude of first appearance; store this minimum amplitude; then the pairing frequency of the sound wave of this minimum amplitude is the frequency of standing wave in pipe, and according to the aerial velocity of propagation of sound wave, the frequency of standing wave and formula, and then try to achieve liquid level ".But measurement environment complexity in the phonocatheter of this method, signal to noise ratio (S/N ratio) is also little, determines that in time domain the amplitude smallest point is easily affected by noise.Synchronous signal collection, processing mode complexity are as needing control chip, analog/digital converter and microprocessor.
Summary of the invention
At above-mentioned prior art situation, the purpose of this utility model is, a kind of liquid level emasuring device based on sound standing wave method and sound card is provided.
Now inventive concept of the present utility model and technical solution are described below:
Inventive concept of the present utility model is based on theoretical analysis result, and the liquid level l value for different all can produce one group of standing wave, and the frequency of each standing wave correspondence is resonant frequency.
Wherein, k is k the standing wave that occurs in the frequency range, and its frequency is k the resonant frequency f (k) that obtains in this frequency range, and m is the resonant frequency number, and c is the velocity of sound under this temperature.As seen, if obtain the difference of adjacent two resonant frequencies arbitrarily, just can calculate n (k).
According to the foregoing invention design, a kind of liquid level emasuring device based on sound standing wave method and sound card of the utility model is characterized in that: described device is gathered by phonocatheter, sound wave generating unit, sound wave receiving element, voice signal A/D and the D/A converting unit is formed; Described sound wave generating unit is loudspeaker; Described sound wave receiving element is a microphone; Described voice signal A/D gathers and the D/A converting unit is the sound card of household PC; Wedge plug is equipped with on the top of phonocatheter; Loudspeaker and microphone package can be separated with phonocatheter in wedge plug.
The utility model further provides a kind of liquid level emasuring device based on sound standing wave method and sound card, it is characterized in that: loudspeaker and microphone are installed in phonocatheter one end side by side, the other end of phonocatheter inserts below the liquid level, and loudspeaker and microphone place surface level are liquid level to be measured to the distance of liquid level; Computer inserts the dress wedge plug on phonocatheter top as controller; The float of eliminating because of the measuring error that easily produces the more liquid generation of foam and impurity is housed in the phonocatheter; Microphone inserts computing machine Mike mouth; The earphone mouth of computing machine connects power amplifier and drives loudspeaker; Phonocatheter constraint sonic propagation also produces standing wave; The environment temperature of thermometer collection is used for calibrating the velocity of sound under this environment temperature.
The utility model further provides a kind of liquid level emasuring device based on sound standing wave method and sound card, it is characterized in that: the linear sine sweep signal of the fixed frequency range that the audio frequency sweep generator of described computer sends is 500Hz-2500Hz; Sample frequency is 44100Hz; Receive this linearity sine sweep signal and signal after reflection by Matlab software transfer computer sound card with the microphone that is attached thereto; Standing wave according to producing detects the one group of resonant frequency that occurs in this frequency range by Fast Fourier Transform (FFT), utilizes the equal difference relation and the resonant frequency liquid level reduction formula of adjacent resonant frequency to obtain a plurality of measured values, and they are averaged the back as final level value.
The superiority that the utility model is compared with prior art is: measurement result accurately and signal projector and receiver can be in the phonocatheter road with end, be convenient to carry out single-ended measurement, be fit to the operating environment of reality.And its stability of integrated sound card, the precision of normal domestic use computer all are better than the A/D and the D/A converter of 12 of markets.This method be easy to realize and response speed fast, the total system hardware cost is cheap, can be widely used in the level gauging of flow container.And this system can also be applied to the demonstration of College Physics sound standing wave experiment, can be clear that the waveform of standing wave from the interface of software, compare single-chip microcomputer, this system can change the advantage of program code in addition as being used for teaching demonstration, so more helps the student to understand the forming process of standing wave fully.So the demonstration that is used for the measurement of industry liquid level or is used for education experiment all has very big advantage.
Description of drawings
Fig. 1: the utility model is based on the liquid level emasuring device synoptic diagram of sound standing wave method and sound card
Wherein: 1 computer, 2 wedge plugs, 3 microphones, 4 loudspeaker, 5 floats, 6 phonocatheters
Embodiment
Now be described further as follows to concrete working method of the present utility model in conjunction with the accompanying drawings:
A kind of liquid level emasuring device based on sound standing wave method and sound card of the utility model utilizes the heard sound signal to form standing wave in phonocatheter, measures the resonant frequency that forms standing wave, and then implements level gauging, is made up of phonocatheter 6, loudspeaker 4, microphone 3 and computer 1; Wedge plug 2 is equipped with on the top of phonocatheter 6; Computer 1 inserts the dress wedge plug 2 on phonocatheter 6 tops as controller; The float of eliminating because of the measuring error that easily produces the more liquid generation of foam and impurity 5 is housed in the phonocatheter 6; Microphone 3 inserts computer 1 Mike's mouth; The earphone mouth of computer 1 connects power amplifier and drives loudspeaker 3; Phonocatheter 6 constraint sonic propagations also produce standing wave; The environment temperature of thermometer collection is used for calibrating the velocity of sound under this environment temperature.Utilize sound card, Matlab and metadata acquisition tool case to constitute cheap data acquisition system (DAS), according to audio frequency standing wave signal measurement liquid level in the pipe, realize quick, the accurately measurement of liquid level, automaticity and efficiency of measurement height, accuracy of measurement and good reproducibility, particularly can realize single-ended operation and automatic record, thereby the research of this project has fabulous practical value.This system also can be advantageously applied to the demonstration of College Physics sound standing wave experiment, and can be clearly seen that the waveform of standing wave from the software interface of system, has strengthened the understanding of student to the standing wave forming process.This device utilizes computer sound card to sample and export, and greatly reduce the cost of experiment, and reproducibility is more intense.Utilize the equal difference relation of the adjacent resonant frequency of standing wave, design a kind of brand-new algorithm, to improve measuring accuracy, and the metadata acquisition tool case that utilizes MATLAB to provide, can when carrying out data acquisition, carry out real-time analysis to the data of gathering, flexible and convenient to use.Microphone inserts computing machine Mike mouth, and the earphone mouth of computing machine connects power amplifier and drives loudspeaker, and thermometer can be gathered environment temperature, and phonocatheter constraint sonic propagation also produces standing wave.Commute produces foam and the more liquid of impurity, adopts float to eliminate the measuring error that this factor produces.Select for use cheap on the market microphone and loudspeaker to receive and dispatch sinusoidal sound wave, with computer as controller, in 3s, send the linear sine sweep signal (sample frequency is 44100Hz) of a fixed frequency range (500Hz-2500Hz) with audio frequency sweep generator software, receive this linearity sine sweep signal and signal after reflection by Matlab software transfer computer sound card with the microphone that is attached thereto, according to existing acoustics knowledge, the signal of some frequency can produce standing wave, can detect the one group of resonant frequency that occurs in this frequency range by Fast Fourier Transform (FFT), utilize the equal difference relation and the resonant frequency liquid level reduction formula of adjacent resonant frequency to obtain a plurality of measured values, they are averaged the back as final level value, thereby reduce uncertainty of measurement effectively.The environment temperature of thermometer collection is used for calibrating the velocity of sound under this environment temperature.Software interface is principle with simple and practical, the user just can carry out level gauging as long as click start button, the liquid level display box is used for showing liquid level, and the height in the height picture frame of reporting to the police is provided with voluntarily by the user, and system will report to the police automatically when liquid level meets or exceeds the warning height.
The concrete course of work of this device is as follows:
(1) phonocatheter is vertically inserted below the liquid level to be measured, loudspeaker and microphone are installed in phonocatheter one end side by side, and the other end of phonocatheter inserts below the liquid level, and loudspeaker and microphone place surface level are liquid level to be measured to the distance of liquid level.
(2) in 3s, Survey Software drives computer sound card and plays the interior one group of linear frequency sweep sinusoidal signal (increment is 1Hz) of 500～2500Hz, and the power amplifier that connects through the earphone delivery outlet drives loudspeaker again; The sound wave that this loudspeaker sends is propagated perpendicular to liquid level through phonocatheter, reflects after reaching liquid level, and incident wave and all kinds of reflection wave be by the microphone collection, and is converted to digital signal through sound card and is stored in computer.
(3) some frequency and the liquid level that always has incident wave, reflection wave satisfies the condition that forms standing wave.Signal to the sound card collection is done Fast Fourier Transform (FFT), and ideally the amplitude of standing wave wave amplitude is 4 times of incident wave, and setting threshold finds the bigger frequency of amplitude greater than setting threshold in spectrogram.
(4) standing wave that produces for side frequency, by
Just can calculate liquid level.
Claims (3)
1. liquid level emasuring device based on sound standing wave method and sound card is characterized in that: described device is gathered by phonocatheter, sound wave generating unit, sound wave receiving element, voice signal A/D and the D/A converting unit is formed; Described sound wave generating unit is loudspeaker; Described sound wave receiving element is a microphone; Described voice signal A/D gathers and the D/A converting unit is the sound card of household PC; Wedge plug is equipped with on the top of phonocatheter; Loudspeaker and microphone package can be separated with phonocatheter in wedge plug.
2. a kind of liquid level emasuring device according to claim 1 based on sound standing wave method and sound card, it is characterized in that: described loudspeaker and microphone are installed in phonocatheter one end side by side, the other end of phonocatheter inserts below the liquid level, and loudspeaker and microphone place surface level are liquid level to be measured to the distance of liquid level; The float of eliminating because of the measuring error that easily produces the more liquid generation of foam and impurity is housed in the phonocatheter; Microphone inserts computer Mike mouth; The earphone mouth of computer connects power amplifier and drives loudspeaker; Phonocatheter constraint sonic propagation also produces standing wave; The environment temperature of thermometer collection is used for calibrating the velocity of sound under this environment temperature.
3. a kind of liquid level emasuring device based on sound standing wave method and sound card according to claim 2 is characterized in that: the linear sine sweep signal of the fixed frequency range that the audio frequency sweep generator of described computer sends is 500Hz-2500Hz; Sample frequency is 44100Hz; Receive this linearity sine sweep signal and signal after reflection by Matlab software transfer computer sound card with the microphone that is attached thereto; Standing wave according to producing detects the one group of resonant frequency that occurs in this frequency range by Fast Fourier Transform (FFT), utilizes the equal difference relation and the resonant frequency liquid level reduction formula of adjacent resonant frequency to obtain a plurality of measured values, and they are averaged the back as final level value.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220707051 CN203100824U (en) | 2012-12-14 | 2012-12-14 | Level measurement device based on standing sound wave method and audio card |
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| CN 201220707051 CN203100824U (en) | 2012-12-14 | 2012-12-14 | Level measurement device based on standing sound wave method and audio card |
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| CN203100824U true CN203100824U (en) | 2013-07-31 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104199306A (en) * | 2014-08-27 | 2014-12-10 | 江苏天使电子科技有限公司 | Matlab-based data gathering system |
| CN109141581A (en) * | 2017-06-28 | 2019-01-04 | 中国石油天然气股份有限公司 | Dynamic liquid level automatic monitoring device and operation method thereof |
| CN111781396A (en) * | 2020-06-23 | 2020-10-16 | 晋中学院 | Wind speed measuring method |
| CN111982242A (en) * | 2020-08-14 | 2020-11-24 | 郑州铁路职业技术学院 | A low-frequency acoustic liquid level estimation method based on a two-dimensional dynamic system model |
| CN113093583A (en) * | 2021-03-01 | 2021-07-09 | 上海化工院检测有限公司 | A multi-functional reagent bottle label for laboratory management |
| US11268845B2 (en) * | 2019-08-30 | 2022-03-08 | National Applied Research Laboratories | Liquid level monitoring system and method |
-
2012
- 2012-12-14 CN CN 201220707051 patent/CN203100824U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104199306A (en) * | 2014-08-27 | 2014-12-10 | 江苏天使电子科技有限公司 | Matlab-based data gathering system |
| CN109141581A (en) * | 2017-06-28 | 2019-01-04 | 中国石油天然气股份有限公司 | Dynamic liquid level automatic monitoring device and operation method thereof |
| US11268845B2 (en) * | 2019-08-30 | 2022-03-08 | National Applied Research Laboratories | Liquid level monitoring system and method |
| CN111781396A (en) * | 2020-06-23 | 2020-10-16 | 晋中学院 | Wind speed measuring method |
| CN111982242A (en) * | 2020-08-14 | 2020-11-24 | 郑州铁路职业技术学院 | A low-frequency acoustic liquid level estimation method based on a two-dimensional dynamic system model |
| CN113093583A (en) * | 2021-03-01 | 2021-07-09 | 上海化工院检测有限公司 | A multi-functional reagent bottle label for laboratory management |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130731 Termination date: 20131214 |