CN109579943A - A kind of liquid detection device and method - Google Patents
A kind of liquid detection device and method Download PDFInfo
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- CN109579943A CN109579943A CN201910074783.0A CN201910074783A CN109579943A CN 109579943 A CN109579943 A CN 109579943A CN 201910074783 A CN201910074783 A CN 201910074783A CN 109579943 A CN109579943 A CN 109579943A
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- 238000001514 detection method Methods 0.000 title claims abstract description 68
- 239000007788 liquid Substances 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 15
- 239000000523 sample Substances 0.000 claims abstract description 53
- 238000005070 sampling Methods 0.000 claims abstract description 49
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229960001484 edetic acid Drugs 0.000 claims abstract description 4
- 239000003990 capacitor Substances 0.000 claims description 19
- 230000035945 sensitivity Effects 0.000 claims description 10
- 230000010355 oscillation Effects 0.000 claims description 4
- 238000009933 burial Methods 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000004088 simulation Methods 0.000 claims description 3
- 238000013461 design Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000005611 electricity Effects 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000011897 real-time detection Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 208000032365 Electromagnetic interference Diseases 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 210000001367 artery Anatomy 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 210000003462 vein Anatomy 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
- G01F23/26—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 variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
- G01F23/263—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 variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
- G01F23/266—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 variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors measuring circuits therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/226—Construction of measuring vessels; Electrodes therefor
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Fluid Mechanics (AREA)
- Thermal Sciences (AREA)
- Electromagnetism (AREA)
- Electrochemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
The invention discloses a kind of liquid detection device and methods, including sampling probe, oscillating circuit and frequency detection circuit, the signal input part of the signal output end connection oscillating circuit of the sampling probe, the signal input part of the signal output end rate of connections detection circuit of the oscillating circuit, the signal output end of the frequency detection circuit are the signal output end of liquid detection device；Method is to carry out detecting liquid level by the frequency for detecting the output signal of sampling probe.The advantages of detection accuracy is high the advantage is that: having, strong antijamming capability, while the circuit design of device is simplified, reduce the complexity of circuit cost and circuit.
Description
Technical field
The present invention relates to detecting liquid levels, and in particular to a kind of liquid detection device and method.
Background technique
In biology, chemistry, medical analysis field, analysis instrument is needed through sampling probe (sample needle) shown in one kind, existing
Detection method be by capacitance-voltage transition detection detection processing and to issue signal.When sampling probe touches liquid, take
Sample needle generates variation so as to cause output signal voltage, issues pulse signal after oversampling circuit is handled.The detection method
The structure of detection circuit is as shown in Figure 5.
In above-mentioned detection method, sampling probe generates capacitance variations according to fluid change, then converts capacitance variations to
Voltage change obtains voltage signal.Voltage signal is obtained into pulse signal after processing of circuit.
In actual use, the capacitance of sampling probe adds often in 30pF or so, and when amount of liquid is fewer
Generated difference is no more than 1pF after sample needle touches liquid level, this is the variation of a small amount.
It is limited by the circuit, the variation of the voltage is also smaller, in order to handle the faint signal, it is necessary to introduce such as Fig. 5
Shown in phaselocked loop capacitance-voltage conversion circuit, filter circuit, comparator circuit etc., it is slow that filter circuit will lead to signal reaction,
The setting of comparator thresholding is inflexible.The movement of sample needle and extraction liquid require motor, the participation of water pump etc..Both
Device is main electromagnetic interference source, can be had an impact to phase-locked loop circuit comparator circuit.The waveform of output signal such as Fig. 6
It is shown.It can be seen that the useful signal in the above method is doped with a large amount of interference signal by the figure, be unfavorable for detection signal
Judgement.
In conclusion existing detection method improves detection sensitivity there is the contradiction of sensitivity and anti-interference
The anti-interference that will lead to instrument simultaneously reduces, and influences testing result.And the anti-interference for improving instrument then will lead to sensitivity
It reduces, can not detect less amount of liquid.
Summary of the invention
In order to solve the above-mentioned problems of the prior art, it is an object of that present invention to provide a kind of liquid detection device and sides
Method.Detection accuracy of the invention is high, strong antijamming capability, while simplifying circuit structure.
A kind of liquid detection device of the present invention, including sampling probe, oscillating circuit and frequency detection circuit, it is described
The signal input part of the signal output end connection oscillating circuit of sampling probe, the signal output end rate of connections of the oscillating circuit
The signal input part of detection circuit, the signal output end of the frequency detection circuit are the signal output end of liquid detection device.
Preferably, the oscillating circuit is 555 oscillating circuits, and 555 oscillating circuits include 555 chips, adjust
Resistance and adjusting capacitor, 555 chips include that electric discharge pin, threshold value pin and triggering pin, the electric discharge pin are logical
It overregulates resistance and is shorted threshold value pin, capacitance connection mould is overregulated in the threshold value pin short contact common end after foot of carrying out the coffin upon burial
The signal output end on quasi- ground, the sampling probe connects threshold value pin.
Preferably, the frequency detection circuit includes MCU, the first driving switch and the second driving switch, and described
One driving switch and the second driving switch are separately connected two gear pins of MCU, further include for being shorted the first driving switch
With the jumper cap of the second driving switch.
A kind of detecting liquid level method is that the frequency for the output signal for passing through detection sampling probe carries out detecting liquid level.
Preferably, sampling probe detection liquid level generates signal and is input in oscillating circuit, and oscillating circuit inputs sampling probe
Signal be converted into oscillator signal and be output in frequency detection circuit, the frequency of frequency detection circuit detection oscillator signal；Work as institute
Fluctuating range of the frequency stated lower than idling frequency and in the unit time is greater than threshold value, determines that liquid level is in cleaning state；Work as institute
Fluctuating range of the frequency stated lower than idling frequency and in the unit time is less than threshold value, determines that liquid level is in contact condition, described
Idling frequency be sampling probe not in contact with liquid level when steady frequency.
Preferably, the first driving switch is shorted by jumper cap and the sensitive of frequency detection circuit is arranged in the second driving switch
Degree.
Preferably, by the signal output end of the sampling probe and connect adjust resistance and adjust capacitor, pass through setting adjust
The sensitivity that the resistance value of resistance and the capacitance setting sampling probe for adjusting capacitor detect.
A kind of liquid detection device of the present invention and method, the advantage is that:
1, the present invention is relative to traditional detecting instrument, no setting is required phase-locked loop circuit and comparator circuit, makes the present invention
The interference in the electromagnetic interferences such as motor, water pump source is not will receive.The present invention has higher anti-interference ability, while solving biography
The sensitivity of instrument and the contradictory problems of anti-interference ability of uniting have high measurement accuracy while possessing strong anti-interference ability.
2, the circuit design for simplifying device reduces the complexity of circuit cost and circuit.With low cost, high stable
Property, detection range it is big and the advantages of be easier to installation and debugging.
Detailed description of the invention
Fig. 1 is a kind of structural schematic diagram of liquid detection device of the present invention；
Fig. 2 is a kind of circuit diagram of the oscillating circuit of liquid detection device of the present invention；
Fig. 3 is a kind of circuit diagram of the frequency detection circuit of liquid detection device of the present invention；
Fig. 4 is a kind of pulse signal of the frequency detection circuit frequency detected of liquid detection device of the present invention
Number-time diagram；
Fig. 5 is the circuit diagram of the detection circuit based on phase-locked loop circuit in the prior art；
Fig. 6 is the signal output waveform figure of circuit shown in fig. 5；
Fig. 7 is a kind of signal output waveform figure of the frequency detection circuit of liquid detection device of the present invention.
Description of symbols: 1- sampling probe, 2- oscillating circuit, 3- frequency detection circuit, R3- adjust resistance, and C3- adjusts electricity
Hold.
Specific embodiment
As shown in Figure 1, a kind of liquid detection device of the present invention, including sampling probe 1, oscillating circuit 2 and frequency inspection
Slowdown monitoring circuit 3, the signal input part of the signal output end connection oscillating circuit 2 of the sampling probe 1, the oscillating circuit 2
The signal input part of signal output end rate of connections detection circuit 3.
The operation principle of the present invention is that: sensor is regard sampling probe 1 as using oscillating circuit 2, forms oscillation circuit, and defeated
Oscillator signal is to frequency detection circuit 3 out, and when sampling probe 1 touches liquid, the frequency of oscillator signal changes, frequency inspection
Slowdown monitoring circuit 3 detects frequency variation so that judgement touches liquid, and is judged according to set gear, and output detects
Signal.
The oscillating circuit 2 can be various 555 oscillating circuits in the prior art.The 555 oscillating circuit packets
555 chips are included, resistance R3 is adjusted and adjust capacitor C3,555 chips include that electric discharge pin, threshold value pin and triggering are drawn
Foot, the electric discharge pin are shorted threshold value pin by adjusting resistance R3, and the threshold value pin short contact is carried out the coffin upon burial the public affairs after foot
Capacitor C3 connection simulation ground is overregulated at end altogether, and the signal output end of the sampling probe connects threshold value pin.555 oscillating circuits
It is easily achieved, stable signal transmission.Oscillating circuit of the invention can be selected but be not limited to 555 oscillating circuits.555 oscillation electricity
The circuit structure on road by 555 simulation timers as shown in Fig. 2, mainly add peripheral circuit to form, the circuit is using sampling probe as biography
Sensor.When sampling probe is not exposed to liquid, its own can be considered as a small capacitor, the capacitor and this electricity
Road forms an oscillator, and exports the signal of a fixed frequency, which is idling frequency.When sampling probe and liquid
When body contacts, faint variation occurs for the capacitor that liquid will lead to sampling probe itself.To which the output frequency of circuit changes,
Changed by the MCU real-time detection frequency, can judge that sampling probe is in contact with liquid.The output frequency of oscillator and week
The calculation formula of phase is as follows:
Cycle T=1.386 × R × C
R: the charge and discharge resistance of oscillator, the adjusting resistance R3 in as Fig. 2
C: the charge and discharge capacitance of oscillator is the equivalent electricity that adjusting capacitor C3 in Fig. 2 and sampling probe capacitor compose in parallel
Hold.Before and after sampling probe contact liq, frequency changes, can compare to judge by frequency values whether
There is contact liq.
The output frequency for adjusting the adjustable oscillating circuit of capacitor C3, avoids output frequency is excessively high MCU is caused to can't detect,
Adjusting capacitor C3 is bigger, and sampling probe sensitivity is lower, and adjusting capacitor C3 is smaller, and sampling probe sensitivity is higher.
Adjusting resistance R3 in oscillating circuit adjusts the parameter of capacitor C3, can be according to the capacitor of sampling probe contact liq
Variation is to choose, flexible setting.
The frequency detection circuit 3 includes MCU, the first driving switch and the second driving switch, first gear
Switch connects two gear pins of MCU with the second driving switch, further includes for being shorted the first driving switch and the second gear
The jumper cap of switch.
Frequency detection circuit 3 as shown in Figure 3 is mainly by MCU, and crystal oscillating circuit, reset circuit composition, wherein JP1, JP2 make
For GSS Gear Select Switch, the first driving switch JP1, the second driving switch JP2 can be shorted by jumper cap to set triggering
Threshold value, select suitable sensitivity, provide flexibility ratio for user.Reset circuit and crystal oscillating circuit be separately connected No. 4 of MCU and
No. 5 pins, oscillator signal are inputted from No. 16 pins of MCU, and oscillator signal is indicated with T1 in figure.Used in frequency detection circuit
MCU model N76E003 can have many models as the MCU of frequency detecting, can also using the MCU of other models
To complete the function of frequency detecting.
A kind of detecting liquid level method is that the frequency for the output signal for passing through detection sampling probe 1 carries out detecting liquid level.
Sampling probe 1 detects liquid level and generates signal and be input in oscillating circuit 2, the letter that oscillating circuit 2 inputs sampling probe 1
Number being converted into oscillator signal is output in frequency detection circuit 3, the frequency of 3 detection oscillator signal of frequency detection circuit；When described
Frequency is lower than idling frequency and fluctuating range in the unit time is greater than threshold value, determine that liquid level is in cleaning state；When described
Frequency is lower than idling frequency and fluctuating range in the unit time is less than threshold value, determine that liquid level is in contact condition, it is described
Idling frequency is steady frequency of the sampling probe 1 not in contact with liquid level.The threshold value is the fluctuating range threshold value of the frequency of oscillator signal.
Sampling probe and oscillating circuit export stable square wave, and the waveform diagram of the square wave exported is as shown in fig. 7, can by Fig. 7
Know do not occur interference signal in the square wave that the present invention is exported.Fig. 7 and Fig. 6 is compared, hence it is evident that obtain output signal of the invention
Square wave be not present interference signal, be more advantageous to the judgement of output signal.By taking current parameter as an example, by sampling probe and oscillation electricity
Road output is set in 380K or so, when sampling probe touches a small amount of liquid, the variation of the frequency of generation be about 500Hz with
On, when amount of liquid is more, capacitance variations are bigger, and frequency variation is bigger.It is primary using 10ms in order to improve the real-time of detection
Sampling period.First 10ms will collect 3800 pulses, when touching liquid, collect 3795 pulses.Arteries and veins
When the changing value of punching is 5 or more, after MCU detects stable variation, output signal.The frequency that real-time detection obtains
Pulse signal number-temporal image is as shown in Figure 4.Be compared to the variation of voltage vulnerable to interference, the detection of frequency is not allowed then
Vulnerable to interference.And it is good at the advantages of handling Digital Logic using MCU, abnormal sample can also be filtered on software
It removes.
For those skilled in the art, it can make other each according to the above description of the technical scheme and ideas
The corresponding change of kind and deformation, and all these changes and deformation all should belong to the protection model of the claims in the present invention
Within enclosing.
Claims (7)
1. a kind of liquid detection device, which is characterized in that including sampling probe (1), oscillating circuit (2) and frequency detection circuit (3),
The signal input part of signal output end connection oscillating circuit (2) of the sampling probe (1), the letter of the oscillating circuit (2)
The signal input part of number output end rate of connections detection circuit (3), the signal output end of the frequency detection circuit are that liquid level is visited
Survey the signal output end of device.
2. a kind of liquid detection device according to claim 1, which is characterized in that the oscillating circuit (2) is 555 oscillations
Circuit, 555 oscillating circuits include 555 chips, adjust resistance (R3) and adjust capacitor (C3), the 555 chip packets
Electric discharge pin, threshold value pin and triggering pin are included, the electric discharge pin is shorted threshold value pin by adjusting resistance (R3), described
The threshold value pin short contact common end after foot of carrying out the coffin upon burial overregulated capacitor (C3) connection simulation ground, the signal of the sampling probe
Output end connects threshold value pin.
3. a kind of liquid detection device according to claim 1, which is characterized in that the frequency detection circuit (3) includes
MCU, the first driving switch and the second driving switch, first driving switch and the second driving switch are separately connected MCU's
Two gear pins further include the jumper cap for being shorted the first driving switch and the second driving switch.
4. a kind of method using any liquid detection device of claim 1-3, which is characterized in that by detecting sampling probe
(1) frequency of output signal carries out detecting liquid level.
5. a kind of detecting liquid level method according to claim 4, which is characterized in that sampling probe (1) detects liquid level and generates signal
And be input in oscillating circuit (2), oscillating circuit (2) converts oscillator signal for the signal that sampling probe (1) inputs and is output to frequency
In rate detection circuit (3), the frequency of frequency detection circuit (3) detection oscillator signal；When the frequency lower than idling frequency and
Fluctuating range in unit time is greater than threshold value, determines that liquid level is in cleaning state；When the frequency lower than idling frequency and
Fluctuating range in unit time is less than threshold value, determines that liquid level be in contact condition, the idling frequency for sampling probe (1) not
Contact steady frequency when liquid level.
6. a kind of detecting liquid level method according to claim 5, which is characterized in that be shorted the first driving switch by jumper cap
With the sensitivity of the second driving switch setting frequency detection circuit (3).
7. a kind of detecting liquid level method according to claim 5, which is characterized in that the signal of the sampling probe (1) is defeated
Outlet simultaneously connects adjusting resistance (R3) and adjusts capacitor (C3), and the resistance value and adjusting capacitor (C3) of resistance (R3) are adjusted by setting
Capacitance setting sampling probe (1) detect sensitivity.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910074783.0A CN109579943A (en) | 2019-01-25 | 2019-01-25 | A kind of liquid detection device and method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910074783.0A CN109579943A (en) | 2019-01-25 | 2019-01-25 | A kind of liquid detection device and method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113514129A (en) * | 2021-06-28 | 2021-10-19 | 安徽伊普诺康生物技术股份有限公司 | Liquid level detection system and method |
| CN114295179A (en) * | 2021-12-28 | 2022-04-08 | 南京颐兰贝生物科技有限责任公司 | Antistatic liquid level detection system and detection method |
| CN115790777A (en) * | 2023-01-05 | 2023-03-14 | 山东康华生物医疗科技股份有限公司 | Liquid level detection device |
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| CN101975603A (en) * | 2010-10-27 | 2011-02-16 | 长沙开元仪器股份有限公司 | Liquid level detector |
| CN203274849U (en) * | 2013-05-28 | 2013-11-06 | 深圳市希莱恒医用电子有限公司 | Liquid level detection device applied to medical detection instrument |
| CN107290027A (en) * | 2016-03-31 | 2017-10-24 | 深圳迈瑞生物医疗电子股份有限公司 | Liquid level sensor and detection method and Full-automatic picking sampling device |
| CN209310883U (en) * | 2019-01-25 | 2019-08-27 | 广州眺望电子科技有限公司 | A kind of liquid detection device |
-
2019
- 2019-01-25 CN CN201910074783.0A patent/CN109579943A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000213979A (en) * | 1999-01-25 | 2000-08-04 | Yamatake Corp | Ultrasonic sensor and detection method of object to be detected using it |
| CN101975603A (en) * | 2010-10-27 | 2011-02-16 | 长沙开元仪器股份有限公司 | Liquid level detector |
| CN203274849U (en) * | 2013-05-28 | 2013-11-06 | 深圳市希莱恒医用电子有限公司 | Liquid level detection device applied to medical detection instrument |
| CN107290027A (en) * | 2016-03-31 | 2017-10-24 | 深圳迈瑞生物医疗电子股份有限公司 | Liquid level sensor and detection method and Full-automatic picking sampling device |
| CN209310883U (en) * | 2019-01-25 | 2019-08-27 | 广州眺望电子科技有限公司 | A kind of liquid detection device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113514129A (en) * | 2021-06-28 | 2021-10-19 | 安徽伊普诺康生物技术股份有限公司 | Liquid level detection system and method |
| CN114295179A (en) * | 2021-12-28 | 2022-04-08 | 南京颐兰贝生物科技有限责任公司 | Antistatic liquid level detection system and detection method |
| CN115790777A (en) * | 2023-01-05 | 2023-03-14 | 山东康华生物医疗科技股份有限公司 | Liquid level detection device |
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