CN110160603B - Oil cup liquid level measuring device of range hood - Google Patents
Oil cup liquid level measuring device of range hood Download PDFInfo
- Publication number
- CN110160603B CN110160603B CN201810141747.7A CN201810141747A CN110160603B CN 110160603 B CN110160603 B CN 110160603B CN 201810141747 A CN201810141747 A CN 201810141747A CN 110160603 B CN110160603 B CN 110160603B
- Authority
- CN
- China
- Prior art keywords
- ultrasonic
- analog
- oil cup
- signal
- digital converter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000007788 liquid Substances 0.000 title claims abstract description 38
- 230000005284 excitation Effects 0.000 claims abstract description 23
- 238000005259 measurement Methods 0.000 claims abstract description 3
- 238000005070 sampling Methods 0.000 claims description 67
- 239000000919 ceramic Substances 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 230000009191 jumping Effects 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 23
- 238000000034 method Methods 0.000 abstract description 10
- 230000002035 prolonged effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000005526 G1 to G0 transition Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000035772 mutation Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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
Abstract
The utility model provides an oil cup liquid level measurement device of range hood which characterized in that: comprises an ultrasonic wave transmitting tube and a digital-analog converterConverter, ultrasonic wave receiving tube, analog-to-digital converter and main control chip, the analog-to-digital converter produces ultrasonic wave excitation signalThe following conditions are satisfied:the ultrasonic excitation signalAnd the main control chip controls the analog-to-digital converter to start at the time t=NT and sample the ultrasonic reflection signal. The invention has the advantages that: design brand new ultrasonic excitation signalThe method adopts a phase jump mode, and the abrupt change signal can be received at the ultrasonic receiving end, so that the signal at the receiving end is detected more simply and accurately; on the premise of ensuring the detection precision, the service life of the detection device can be effectively prolonged, and the overall performance of the product is improved.
Description
Technical Field
The invention relates to a liquid level measuring device, in particular to an oil cup liquid level measuring device of a range hood.
Background
The greasy dirt that the range hood produced in the use can be discharged into the oil cup in, generally, the liquid level of oil in the oil cup needs the manual observation to detect, needs in time to pour the greasy dirt in order to prevent spilling over after accumulating certain liquid level height. In order to facilitate the observation of the liquid level of the oil cup, most of the traditional oil cup of the range hood is made of transparent plastic, but the oil cup made of plastic has the problems of low strength and easy aging; there are also oil cups made of metal, which are not convenient to observe the liquid level of the oil cup although the strength is high, and even if the observation window exists, oil stains adhere to the observation window after long-time use, so that a user cannot see the liquid level of the oil cup clearly.
Aiming at the problems, various devices for automatically detecting the liquid level of the oil cup appear in the prior art, such as the heating type thermistor on a detection circuit of the oil cup of the range hood in the China patent No. ZL201310653491.5, which heats the oil in the oil cup and detects the temperature of the oil so as to analyze and obtain the height of the oil, but the contact type detection mode greatly reduces the service life of electronic components in an oil pollution environment, thereby reducing the detection precision and affecting the detection accuracy; as another example, the chinese application of application number 201510386967.2, namely, "oil level guard device for oil cup of range hood", discloses an oil level detection device that detects the oil cup guard level through a device such as a float placed in the oil cup, but the device has the disadvantages that the service life of the float is reduced due to long-time soaking in oil stain, and the detection accuracy is not high.
Disclosure of Invention
The invention aims to solve the technical problem of providing the oil cup liquid level detection device of the range hood, which has long service life and high detection precision, aiming at the current state of the art.
The technical scheme adopted for solving the technical problems is as follows: the utility model provides an oil cup liquid level measurement device of range hood which characterized in that: the oil cup liquid level measuring device comprises an ultrasonic transmitting tube, a digital-to-analog converter, an ultrasonic receiving tube, an analog-to-digital converter and a main control chip, wherein the digital-to-analog converter is electrically connected with the ultrasonic transmitting tube, the analog-to-digital converter is electrically connected with the ultrasonic receiving tube, and the digital-to-analog converter and the analog-to-digital converter are respectively and electrically connected with the main control chip; the main control chip controls the digital-to-analog converter to generate ultrasonic excitation signalsThe ultrasonic excitation signal->The following conditions are satisfied:
wherein N is a positive integer, T is a resonance period and satisfies ω s0 T=2pi, the U m Is an ultrasonic excitation signalMaximum voltage of said omega s0 Is the resonant angular frequency; the ultrasonic excitation signal->And the main control chip controls the analog-to-digital converter to start at the time t=NT and sample the ultrasonic reflection signal.
Preferably, the ultrasonic transmitting tube and the ultrasonic receiving tube may respectively adopt piezoelectric ceramic transducers, and the core device is a piezoelectric vibrator.
Preferably, the sampling frequency f of the analog-to-digital converter samp ＝2N samp F, wherein f is the frequency of the ultrasonic excitation signal and satisfiesThe N is samp Is the number of samples in a half sampling period.
As a further preference, the number of sampling points N samp The value range is 2-16, N is used samp =8 is optimal.
In order to facilitate installation and further improve detection accuracy and reaction sensitivity, preferably, the oil cup liquid level measuring device is arranged in the range hood main body right above the oil cup, and the ultrasonic transmitting tube and the ultrasonic receiving tube are arranged side by side and are positioned in the same horizontal plane.
Considering that the ultrasonic wave receiving signal has a certain time offset, according to the change of the ultrasonic wave transmitting signal, preferably, the ultrasonic wave reflecting signal collected by the analog-to-digital converter comprises an initial stage of gradually increasing the signal amplitude, a stable stage of keeping stable signal amplitude and a sudden change stage of jumping the signal amplitude.
Compared with the prior art, the invention has the advantages that: aiming at the problem of inaccurate detection of initial pulse of receiving point in the traditional ultrasonic ranging scheme, a brand-new ultrasonic excitation signal is designedThe method adopts a phase jump mode, and the abrupt change signal can be received at the ultrasonic receiving end, so that the signal at the receiving end is detected more simply and accurately; because the ultrasonic wave can adapt to various adverse environments, the traditional contact type detection device is not interfered by oil smoke pollution and the like, the service life of the detection device can be effectively prolonged and the overall performance of the product can be improved on the premise of ensuring the detection precision.
Drawings
Fig. 1 is an installation schematic diagram of an oil cup liquid level detection device according to an embodiment of the invention.
Fig. 2 is a system configuration diagram of an oil cup liquid level detection device according to an embodiment of the present invention.
Fig. 3 is a flowchart of a method for measuring the liquid level of an oil cup according to an embodiment of the present invention.
Fig. 4 is a waveform comparison chart of an ultrasonic excitation signal and an ultrasonic reception signal according to an embodiment of the present invention.
Fig. 5 is a schematic diagram of sampling an ultrasonic received signal in a single sampling period according to an embodiment of the present invention.
Fig. 6 is a waveform diagram and a sampling schematic diagram of an ultrasonic receiving signal from a steady stage to a sudden change stage according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the embodiments of the drawings.
The embodiment relates to an oil cup liquid level measuring device of a range hood, which adopts an ultrasonic ranging principle, and specifically adopts a transit time method TOF (time of flight): firstly, the time delta t (the time delta t is the transit time) from the emission of the ultrasonic wave to the return of the obstacle is measured, and then the distance between the sound source and the obstacle is obtained by multiplying the speed of the ultrasonic wave.
As shown in fig. 1 and fig. 2, which are schematic diagrams of an oil cup liquid level measuring device in the embodiment, the oil cup liquid level measuring device is arranged in a range hood main body right above an oil cup, and the oil cup liquid level measuring device specifically comprises an ultrasonic transmitting tube, a digital-to-analog converter, an ultrasonic receiving tube, an analog-to-digital converter and a main control chip, wherein the ultrasonic transmitting tube and the ultrasonic receiving tube respectively adopt piezoelectric ceramic transducers, and a core device of the ultrasonic transmitting tube and the ultrasonic receiving tube is a piezoelectric vibrator;
the digital-to-analog converter is electrically connected with the ultrasonic transmitting tube, the analog-to-digital converter is electrically connected with the ultrasonic receiving tube, the digital-to-analog converter and the analog-to-digital converter are respectively electrically connected with the main control chip, and in order to further improve the detection precision and the response sensitivity, the ultrasonic transmitting tube and the ultrasonic receiving tube are arranged in the same horizontal plane, so that the ultrasonic receiving signals transmitted to the liquid level of the oil cup and reflected from the liquid level of the oil cup are the shortest distances, and the response sensitivity of the detection device is improved;
the main control chip controls the digital-to-analog converter to generate ultrasonic excitation signalsThe ultrasonic excitation signal->The following conditions are satisfied:
wherein N is a positive integer, T is a resonance period and satisfies ω s0 ·T＝2π，U m Is an ultrasonic excitation signalMaximum voltage of omega s0 Is the resonant angular frequency; the ultrasonic excitation signal->And the main control chip controls the analog-to-digital converter to start at the time t=NT and sample the ultrasonic reflection signal.
Setting the height of an ultrasonic wave transmitting tube from the bottom surface of an oil cup as H, setting the liquid level height of the oil cup as H, and obtaining the formula according to a transit time method: cΔt=2 (H-H), wherein C is the propagation speed of the ultrasonic wave in air; the ultrasonic wave propagates through the air and then is reflected when meeting the liquid plane of the oil cup, and finally the ultrasonic wave receiving tube transmits the received reflected signal to the analog-to-digital converter for sampling processing.
As shown in fig. 3 to 6, the method for measuring the liquid level of the oil cup in this embodiment includes the following steps:
(1) The main control chip controls the digital-to-analog converter to generate ultrasonic excitation signals
(2) The main control chip controls the analog-to-digital converter to start at the time t=NT, and a sampling module of the analog-to-digital converter samples the ultrasonic reflected signal; setting the sampling frequency f of the analog-to-digital converter samp ＝2N samp F, wherein f is the frequency of the ultrasonic excitation signal and satisfiesN samp For the number of sampling points in half a sampling period, see fig. 5, the number of sampling points N samp The value range is 2-16, N is preferable in this embodiment samp =8, i.e. the number of samples in one sampling period is 16;
(3) Judging whether the current sampling signal has signal mutation or not by the main control chip, if so, executing the next step; if not, the step is circulated;
(4) Calculating the transition time delta t of the analog-to-digital converter when the analog-to-digital converter receives the abrupt signal by the main control chip;
(5) Obtaining the liquid levelWherein H is the height of the ultrasonic wave transmitting tube from the bottom surface of the oil cup, H is the liquid level height of the oil cup, and C is the propagation speed of ultrasonic waves in the air.
In the step (2), the ultrasonic reflected signal collected by the analog-to-digital converter includes an initial stage in which the signal amplitude is gradually increased, a stable stage in which the signal amplitude is kept stable, and a sudden change stage in which the signal amplitude jumps, and after the sampling is started, the signal amplitude before the initial stage is zero because the ultrasonic signal is not received at the beginning.
According to the waveform of the ultrasonic excitation signal, the ultrasonic receiving signal of the present embodiment approximates to a sinusoidal signal, and the current sampling value is set to be ad_now, the previous sampling value of the current sampling value is set to be ad_ bef, the difference value Δad_now=ad_now-ad_ bef between the current adjacent sampling values, and the difference value Δad_ bef =ad_ bef-ad_ bef 'between the previous adjacent sampling values, wherein ad_ bef' is the previous sampling value adjacent to the previous sampling value;
if the current sampling value is equal to the previous sampling value and is zero, that is, ad_now=ad_ bef =0, it indicates that the ultrasonic receiving end has not received the ultrasonic reflected signal, and the ultrasonic received signal is before the initial stage.
Waiting until the ultrasonic receiver receives the initial signal, the sampling signal at the initial stage comprises the following characteristics:
a. the maximum value ad_max_now of the current sampling value is larger than the maximum value ad_max_ bef of the previous sampling value;
b. the minimum value ad_min_now of the current sampling value is smaller than the minimum value ad_min_ bef of the previous sampling value;
c. the maximum value delta ad_max_now of the difference between the current adjacent sampling values is larger than the maximum value delta ad_max_ bef of the difference between the previous adjacent sampling values;
d. the minimum difference value aad_min_now between the current adjacent sample values is greater than the minimum difference value aad_min_ bef between the previous adjacent sample values.
The four characteristics a, b, c, d indicate that the ultrasonic wave starts to receive the initial signal of the ultrasonic wave signal reflected by the liquid surface of the oil cup, and meanwhile, the main control chip stores sampling points of the current two sampling periods.
The signal received in the ultrasonic wave receiving signal stabilization stage is a stable sine wave, and the sampling signal in the stabilization stage comprises the following characteristics:
a. the maximum value ad_max_now of the current sample value is equal to the maximum value ad_max_ bef of the previous sample value;
b. the minimum value ad_min_now of the current sample value is equal to the minimum value ad_min_ bef of the previous sample value;
c. the maximum value of the difference deltaad_max_now between the current adjacent sampling values is equal to the maximum value of the difference deltaad_max_ bef between the previous adjacent sampling values;
d. the difference minimum value aad_min_now between the current neighboring sample values is equal to the difference minimum value aad_min_ bef between the previous neighboring sample values.
After receiving the stable sine wave signal, the ultrasonic receiving end receives the abrupt change signal, and sets the time domain of the ultrasonic receiving signal as r (t), and the difference between the stable phase and the abrupt change phase of the ultrasonic receiving signal is: (1) the maximum sampling value of the stable phase is larger than the maximum sampling value of the abrupt phase, and the minimum sampling value of the stable phase is smaller than the minimum sampling value of the abrupt phase; (2) for a sinusoidal function, the derivative is the largest when the readily available phase is 0 or pi, that is, the maximum value of the steady-phase difference is greater than the maximum value of the abrupt-phase difference, and the minimum value of the steady-phase difference is less than the minimum value of the abrupt-phase difference.
Thus, during the transition from the stationary phase to the abrupt phase, the sampled signal of the abrupt phase comprises the following features:
a. the maximum value ad_max_now of the current sampling value is smaller than the maximum value ad_max_ bef of the previous sampling value;
b. the minimum value ad_min_now of the current sampling value is larger than the minimum value ad_min_ bef of the previous sampling value;
c. the maximum value delta ad_max_now of the difference between the current adjacent sampling values is smaller than the maximum value delta ad_max_ bef of the difference between the previous adjacent sampling values;
d. the minimum difference value aad_min_now between the current adjacent sample values is greater than the minimum difference value aad_min_ bef between the previous adjacent sample values.
Considering that a certain clock bias may exist during sampling of the ultrasonic receiving end, when an abrupt signal occurs, the sampling point is difficult to directly acquire the moment when the signal amplitude is zero, in order to reduce the detection bias of the abrupt signal sampling point and further improve the detection precision, the transit time Δt in the step (4) can be obtained by the following method, see fig. 6:
(4.1) obtaining the current two sampling points A1 and A2 with the maximum difference value, wherein the sampling value corresponding to the sampling point A1 is ad a1 <0, the sampling point value corresponding to the sampling point A1 is M AD The method comprises the steps of carrying out a first treatment on the surface of the The sampling value corresponding to the sampling point A2 is ad a2 >0, the sampling point value corresponding to the sampling point A2 is M AD +1；
(4.2) obtaining the time offset of the time point when the sampling value is 0 with respect to the sampling point A1
(4.3) obtaining the time offset of the starting time of the analog-digital converter starting sampling relative to the sampling point A1
(4.4) obtaining the time of flightWherein f samp Is the sampling frequency.
Then, the liquid level height formula is combined againThe liquid level of the oil cup can be obtained as follows:
aiming at the problem of inaccurate detection of the initial pulse of the receiving end caused by too small amplitude of the initial point of the ultrasonic receiving signal in the traditional ultrasonic ranging scheme, the embodiment designs a brand-new ultrasonic excitation signalAdopts the mode that the sampling of an ultrasonic receiving end is started after the phase jump of an ultrasonic transmitting endThe ultrasonic receiving end can accurately acquire the abrupt change signal with obvious signal characteristic change, so that the transit time delta t can be accurately acquired, and the precision of the final detection result of the liquid level of the oil cup is ensured.
Compared with the traditional high-precision ultrasonic ranging scheme, the method has the advantages that calculation methods such as Fast Fourier Transform (FFT) and the like are needed, the calculation capacity of a main control chip is a great test due to large calculation amount, and the selected main control chip is high in cost; the embodiment designs the ultrasonic high-precision distance measuring method based on the time domain, and only carries out addition and subtraction operation on the sampled analog-digital signals, so that the operation can be realized by adopting a low-cost main control chip, the operation speed is high, the measured distance precision is high, and the reliability and the practicability of the product are strong.
Claims (6)
1. The utility model provides an oil cup liquid level measurement device of range hood which characterized in that: the oil cup liquid level measuring device comprises an ultrasonic transmitting tube, a digital-to-analog converter, an ultrasonic receiving tube, an analog-to-digital converter and a main control chip, wherein the digital-to-analog converter is electrically connected with the ultrasonic transmitting tube, the analog-to-digital converter is electrically connected with the ultrasonic receiving tube, and the digital-to-analog converter and the analog-to-digital converter are respectively and electrically connected with the main control chip; the main control chip controls the digital-to-analog converter to generate ultrasonic excitation signalsThe ultrasonic excitation signal->The following conditions are satisfied:
wherein N is a positive integer, T is a resonance period and satisfies ω s0 T=2pi, the U m Is an ultrasonic excitation signalMaximum voltage of said omega s0 Is the resonant angular frequency;
the ultrasonic excitation signalThe main control chip controls the analog-to-digital converter to start at the time t=NT and samples the ultrasonic reflection signal;
the main control chip calculates the transition time delta t of the analog-to-digital converter when the analog-to-digital converter receives the abrupt signal; liquid level heightWherein H is the height of the ultrasonic wave transmitting tube from the bottom surface of the oil cup, H is the liquid level height of the oil cup, and C is the propagation speed of ultrasonic waves in the air.
2. The oil cup level measuring device of a range hood according to claim 1, wherein: the ultrasonic transmitting tube and the ultrasonic receiving tube respectively adopt piezoelectric ceramic transducers.
3. The oil cup level measuring device of a range hood according to claim 1, wherein: sampling frequency f of the analog-to-digital converter samp ＝2N samp F, wherein f is the frequency of the ultrasonic excitation signal and satisfiesThe N is samp Is the number of samples in a half sampling period.
4. The oil cup level measuring device of a range hood according to claim 3, wherein: the number of sampling points N samp The value range is 2-16.
5. The oil cup level measuring device of a range hood according to claim 1, wherein: the oil cup liquid level measuring device is arranged in the range hood main body right above the oil cup, and the ultrasonic wave transmitting tube and the ultrasonic wave receiving tube are arranged side by side and are positioned in the same horizontal plane.
6. The oil cup level measuring device of a range hood according to claim 1, wherein: the ultrasonic wave reflected signal collected by the analog-to-digital converter comprises an initial stage of gradually increasing the signal amplitude, a stable stage of keeping the signal amplitude stable and a sudden change stage of jumping the signal amplitude.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810141747.7A CN110160603B (en) | 2018-02-11 | 2018-02-11 | Oil cup liquid level measuring device of range hood |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810141747.7A CN110160603B (en) | 2018-02-11 | 2018-02-11 | Oil cup liquid level measuring device of range hood |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110160603A CN110160603A (en) | 2019-08-23 |
| CN110160603B true CN110160603B (en) | 2024-01-26 |
Family
ID=67634978
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810141747.7A Active CN110160603B (en) | 2018-02-11 | 2018-02-11 | Oil cup liquid level measuring device of range hood |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110160603B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113109434A (en) * | 2021-04-13 | 2021-07-13 | 重庆山外山血液净化技术股份有限公司 | Precise ultrasonic bubble detection device and detection method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2432568Y (en) * | 2000-07-13 | 2001-05-30 | 蒋志高 | Ultrasonic level and volume measuring instrument special for underground tank of double-fuel fuel-filling and gas-filling station |
| EP1859236A1 (en) * | 2005-03-18 | 2007-11-28 | Hella KGaA Hueck & Co. | Device for measuring the level of a liquid in a container by means of an ultrasonic converter |
| CN102858211A (en) * | 2010-04-27 | 2013-01-02 | 雀巢产品技术援助有限公司 | Beverage machine with integrated ultrasonic transceiver |
| CN203489945U (en) * | 2013-09-29 | 2014-03-19 | 中科隆声（北京）科技有限责任公司 | External attaching type ultrasound liquid level meter |
| CN208091536U (en) * | 2018-02-11 | 2018-11-13 | 宁波方太厨具有限公司 | A kind of lubricating cup liquid level emasuring device of range hood |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3810430B2 (en) * | 2004-04-28 | 2006-08-16 | 松下電器産業株式会社 | Ultrasonic ranging device |
-
2018
- 2018-02-11 CN CN201810141747.7A patent/CN110160603B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2432568Y (en) * | 2000-07-13 | 2001-05-30 | 蒋志高 | Ultrasonic level and volume measuring instrument special for underground tank of double-fuel fuel-filling and gas-filling station |
| EP1859236A1 (en) * | 2005-03-18 | 2007-11-28 | Hella KGaA Hueck & Co. | Device for measuring the level of a liquid in a container by means of an ultrasonic converter |
| CN102858211A (en) * | 2010-04-27 | 2013-01-02 | 雀巢产品技术援助有限公司 | Beverage machine with integrated ultrasonic transceiver |
| CN203489945U (en) * | 2013-09-29 | 2014-03-19 | 中科隆声（北京）科技有限责任公司 | External attaching type ultrasound liquid level meter |
| CN208091536U (en) * | 2018-02-11 | 2018-11-13 | 宁波方太厨具有限公司 | A kind of lubricating cup liquid level emasuring device of range hood |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110160603A (en) | 2019-08-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101269284B1 (en) | Method of ultrasonic flow measurement and ultrasonic flow meter | |
| EP1770409B1 (en) | Time-of-flight-ranging system and method for calibrating such a system | |
| US6305233B1 (en) | Digital speed determination in ultrasonic flow measurements | |
| CN208091536U (en) | A kind of lubricating cup liquid level emasuring device of range hood | |
| JPH02500682A (en) | Method for displaying the time of a sound pulse and apparatus for carrying out the method | |
| US20160097669A1 (en) | Level finding using multiple search steps | |
| CN110160603B (en) | Oil cup liquid level measuring device of range hood | |
| KR101688844B1 (en) | Method for determining the starting instant of a periodically oscillating signal response | |
| KR20120059919A (en) | Towing tank using ultrasonic measurement of ice thickness measurement system and method | |
| RU2323131C1 (en) | Method and device for detection of icing | |
| GB2472085A (en) | Methods and apparatus for determining the time of receipt of a received signal | |
| CN110160602B (en) | Oil cup liquid level measuring method of range hood | |
| CN205785491U (en) | A kind of Sound speed profile instrument based on TOF technology | |
| CN113970744B (en) | Distance measurement method, system and medium based on linear frequency modulation ultrasonic wave | |
| KR100739506B1 (en) | Ultrasonic distance measuring method using matched filter of reduced calculation | |
| CN113740856B (en) | Distance measurement method and device based on ultrasonic wave waveform vibration starting characteristics | |
| US10634544B1 (en) | Ultrasonic short range moving object detection | |
| KR20170035555A (en) | Signal processing system for ultrasonic floemeter | |
| CN201697603U (en) | Ice sensor adopting vibration tube principle | |
| JP6404844B2 (en) | Ultrasonic receiver | |
| US7954378B2 (en) | Ultrasonic sensor and method for determining a separation of an object from an ultrasonic sensor | |
| CN111596286A (en) | Distance measuring method and device | |
| RU2307325C1 (en) | Method for determining angular speed of laser gyroscope and systems based thereon | |
| CN115752661B (en) | Liquid level calibration method based on lamb wave out-of-plane energy characteristics | |
| JP2019095306A (en) | Object detector |
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 |