CN114813932A - Liquid component detection method and system - Google Patents

Liquid component detection method and system Download PDF

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CN114813932A
CN114813932A CN202210280313.1A CN202210280313A CN114813932A CN 114813932 A CN114813932 A CN 114813932A CN 202210280313 A CN202210280313 A CN 202210280313A CN 114813932 A CN114813932 A CN 114813932A
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piezoelectric transducer
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刘艺凡
杨增涛
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Chongqing Medical University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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    • G01—MEASURING; TESTING
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    • G01N29/4436—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by comparison with a reference signal
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    • G01—MEASURING; TESTING
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    • G01N2291/022—Liquids
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    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
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Abstract

The invention provides a liquid component detection method and a system, firstly, liquid to be detected in a target container is obtained; then contacting a piezoelectric transducer with the target container, or contacting or immersing the piezoelectric transducer with the liquid to be measured, and electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer; and calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and determining the liquid components in the liquid to be detected according to the acoustic impedance. The liquid component in the liquid to be detected can be determined only by utilizing the piezoelectric transducer, so that the detection cost is low, the detection time is short, the detection efficiency is high, and the whole detection equipment is portable and easy to carry.

Description

Liquid component detection method and system
Technical Field
The invention relates to the technical field of liquid detection, in particular to a liquid component detection method and system.
Background
Currently, identifying the composition properties of a liquid helps to monitor the actual state of the liquid to determine the course of a chemical reaction in the liquid. However, some existing liquid component detection methods generally require complex, bulky and expensive detection equipment, and also require personnel capable of skillfully operating the detection equipment, so that not only portable detection cannot be performed each time liquid component detection is performed, but also single detection cost is high, and single detection time is long. Therefore, there is a need for a method for identifying a liquid property that is simple, fast, economical, portable, and provides accurate results.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention provides a liquid composition detection method and system, which is used to solve the problems of high cost, long time and insufficient portability of the existing detection method in the prior art.
To achieve the above and other related objects, the present invention provides a liquid component detecting method, comprising the steps of:
obtaining liquid to be measured in a target container;
contacting a piezoelectric transducer with the target container, or contacting or immersing a piezoelectric transducer with the liquid to be measured;
electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer;
and calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and determining the liquid components in the liquid to be detected according to the acoustic impedance.
Optionally, the method further comprises: and acquiring the electrical impedance amplitude of the piezoelectric transducer under the anti-resonance frequency, and calculating the acoustic impedance of the liquid to be measured based on the electrical impedance amplitude of the piezoelectric transducer.
Optionally, the process of calculating the acoustic impedance of the liquid to be measured based on the electrical impedance of the piezoelectric transducer includes:
obtaining a pre-established model relation between the electrical impedance of the piezoelectric transducer and the acoustic impedance of a liquid substance, combining the model relation with the electrical impedance of the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be measured, wherein the model relation comprises the following steps:
Figure BDA0003556855950000011
Figure BDA0003556855950000022
Figure BDA0003556855950000023
Figure BDA0003556855950000024
Figure BDA0003556855950000025
Figure BDA0003556855950000026
in the formula, C 0 A static capacitance per unit area representing the piezoelectric plate;
c 33 represents the effective elastic constant;
e 33 represents a piezoelectric constant;
ε 33 represents a dielectric constant;
ρ represents the density of the piezoelectric material;
ω represents the angular velocity;
Z PZT represents the electrical impedance of the piezoelectric transducer;
Z L representing the acoustic impedance of the liquid to be measured;
i represents an imaginary number;
h represents the half thickness of the piezoelectric transducer;
s denotes the area of the piezoelectric transducer.
Optionally, the method further comprises:
contacting or immersing piezoelectric transducers with different frequencies with the same liquid to be measured, and acquiring the electrical impedance amplitude of the piezoelectric transducers under each frequency;
and determining the relation between the electrical impedance amplitude and the frequency of the piezoelectric transducer according to the electrical impedance amplitude of the piezoelectric transducer at each frequency.
Optionally, the method further comprises:
recording the electrical impedance obtained after the piezoelectric transducer is contacted with or immersed in the liquid to be measured as actual measured electrical impedance;
and acquiring a reference electrical impedance of the corresponding piezoelectric transducer, comparing the actual measured electrical impedance with the reference electrical impedance, and determining the impedance error of the piezoelectric transducer.
Optionally, the liquid to be measured includes: water, alcohol, castor oil.
The invention also provides a liquid component detection system, comprising:
the power supply module is used for electrifying the piezoelectric transducer after the piezoelectric transducer is contacted with or immersed in liquid to be measured in a target container or the piezoelectric transducer is contacted with the target container;
the electrical impedance acquisition module is used for acquiring the electrical impedance of the piezoelectric transducer after electrification;
the acoustic impedance calculation module is used for calculating the acoustic impedance of the liquid to be measured according to the electrical impedance of the piezoelectric transducer;
and the liquid component detection module is used for determining the liquid components in the liquid to be detected according to the acoustic impedance.
Optionally, the electrical impedance acquisition module further comprises obtaining an electrical impedance magnitude of the piezoelectric transducer at an anti-resonance frequency; the acoustic impedance calculation module further calculates the acoustic impedance of the liquid to be measured according to the electrical impedance amplitude of the piezoelectric transducer.
Optionally, the process of calculating the acoustic impedance of the liquid to be measured by the acoustic impedance calculation module according to the electrical impedance of the piezoelectric transducer includes:
obtaining a pre-established model relation between the electrical impedance of the piezoelectric transducer and the acoustic impedance of a liquid substance, combining the model relation with the electrical impedance of the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be measured, wherein the model relation comprises the following steps:
Figure 1
Figure BDA0003556855950000032
Figure BDA0003556855950000033
Figure BDA0003556855950000041
Figure BDA0003556855950000042
Figure BDA0003556855950000043
in the formula, C 0 A static capacitance per unit area representing the piezoelectric plate;
c 33 represents the effective elastic constant;
e 33 represents a piezoelectric constant;
ε 33 represents a dielectric constant;
ρ represents the density of the piezoelectric material;
ω represents the angular velocity;
Z PZT represents the electrical impedance of the piezoelectric transducer;
Z L representing the acoustic impedance of the liquid to be measured;
i represents an imaginary number;
h represents the half thickness of the piezoelectric transducer;
s denotes the area of the piezoelectric transducer.
Optionally, the liquid to be measured includes: water, alcohol, castor oil.
As described above, the present invention provides a liquid component detection method and system, which have the following beneficial effects: firstly, obtaining liquid to be measured in a target container; then contacting a piezoelectric transducer target container, or contacting the piezoelectric transducer with liquid to be detected, or immersing the piezoelectric transducer in the liquid to be detected, and electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer; and calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and determining the liquid components in the liquid to be detected according to the acoustic impedance. Therefore, the target container of the piezoelectric transducer is contacted, or the piezoelectric transducer is contacted with the liquid to be detected, or the piezoelectric transducer is immersed in the liquid to be detected, then the piezoelectric transducer is electrified, the acoustic impedance of the liquid to be detected is calculated according to the electrical impedance of the piezoelectric transducer, in acoustics, the acoustic impedance is a key inherent characteristic of the liquid, and each liquid has only unique acoustic impedance at a specific temperature, so that the corresponding liquid substance can be searched by detecting the acoustic impedance of the liquid to be detected and referring to the existing liquid acoustic impedance standard, and the liquid component in the liquid to be detected can be obtained. The liquid component in the liquid to be detected can be determined by only utilizing the piezoelectric transducer, so that the detection cost is low, the detection time is short, the detection efficiency is high, and the whole detection equipment is portable and easy to carry.
Drawings
FIG. 1 is a schematic flow chart of a method for detecting a liquid component according to an embodiment;
FIG. 2 is a graph illustrating electrical impedance curves of piezoelectric transducers of two different frequencies in air according to an embodiment;
FIG. 3 is a schematic diagram of electrical impedance curves of two piezoelectric transducers of different frequencies in water according to an embodiment;
FIG. 4 is a graph illustrating electrical impedance curves of two piezoelectric transducers of different frequencies in alcohol according to an embodiment;
FIG. 5 is a graph illustrating electrical impedance curves of two piezoelectric transducers of different frequencies in castor oil according to an exemplary embodiment;
FIG. 6 is a schematic diagram of a hardware configuration of a liquid component detection system according to an embodiment;
fig. 7 is a schematic diagram of a hardware configuration connection of a liquid component detection apparatus according to an embodiment.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
Referring to fig. 1, the present embodiment provides a liquid component detection method, including the following steps:
s100, obtaining liquid to be detected in a target container; as an example, the liquid to be measured in the present embodiment includes but is not limited to: water, alcohol, castor oil, and other liquid substances, and the specific liquid to be measured can be determined according to actual conditions. Meanwhile, the target container is a container used in cooperation with the liquid to be measured, and the target container can be selected according to some physical characteristics of the liquid to be measured, for example, if the liquid to be measured is corrosive, some containers with an anti-corrosion function can be selected as the target container.
S200, contacting a piezoelectric transducer target container, or contacting the piezoelectric transducer with liquid to be detected, or immersing the piezoelectric transducer in the liquid to be detected;
s300, electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer; as an example, in this embodiment, the piezoelectric transducer may be immersed in a half of the liquid to be measured, then the piezoelectric transducer is powered by an external power source, and finally the electrical impedance of the piezoelectric transducer after being powered is detected. As another example, in this embodiment, the piezoelectric transducer may be first contacted with the target container, then an external power source is used to energize the piezoelectric transducer, and finally the electrical impedance of the energized piezoelectric transducer is detected. As yet another example, the present embodiment may be such that immediately after the piezoelectric transducer is brought into contact with the target container, the piezoelectric transducer is then energized using an external power source, and finally the electrical impedance of the piezoelectric transducer after the energization is detected.
S400, calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and matching the liquid components in the liquid to be detected according to the acoustic impedance. Specifically, the process of calculating the acoustic impedance of the liquid to be measured based on the electrical impedance of the piezoelectric transducer includes: obtaining a pre-established model relation between the electrical impedance of the piezoelectric transducer and the acoustic impedance of a liquid substance, combining the model relation with the electrical impedance of the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be measured, wherein the model relation comprises the following steps:
Figure 2
Figure BDA0003556855950000062
Figure BDA0003556855950000063
Figure BDA0003556855950000064
Figure BDA0003556855950000065
Figure BDA0003556855950000066
in the formula, C 0 A static capacitance per unit area representing the piezoelectric plate;
c 33 represents the effective elastic constant;
e 33 represents a piezoelectric constant;
ε 33 represents a dielectric constant;
ρ represents the density of the piezoelectric material;
ω represents the angular velocity;
Z PZT represents the electrical impedance of the piezoelectric transducer;
Z L representing the acoustic impedance of the liquid to be measured;
i represents an imaginary number;
h represents the half thickness of the piezoelectric transducer;
s denotes the area of the piezoelectric transducer.
According to the above, in an exemplary embodiment, the method further includes: and acquiring the electrical impedance amplitude of the piezoelectric transducer under the anti-resonance frequency, and calculating the acoustic impedance of the liquid to be measured based on the electrical impedance amplitude of the piezoelectric transducer. In this embodiment, since the electrical impedance of the piezoelectric transducer is the largest at the anti-resonance frequency, the electrical impedance amplitude of the piezoelectric transducer at the anti-resonance frequency is obtained at this time, and then the acoustic impedance of the liquid to be measured calculated based on the electrical impedance amplitude of the piezoelectric transducer at this time is the highest accuracy, which is equivalent to the highest accuracy of the acoustic impedance of the liquid to be measured obtained according to the electrical impedance amplitude of the piezoelectric transducer.
According to the above, in an exemplary embodiment, the method further includes: contacting or immersing piezoelectric transducers with different frequencies with the same liquid to be measured, and acquiring the electrical impedance amplitude of the piezoelectric transducers under each frequency; and determining the relation between the electrical impedance amplitude and the frequency of the piezoelectric transducer according to the electrical impedance amplitude of the piezoelectric transducer at each frequency. Specifically, as can be seen from fig. 2 to 5, the larger the frequency of the piezoelectric transducer, the smaller the magnitude of the electrical impedance in the same liquid to be measured. Wherein, fig. 2 is a graph illustrating the electrical impedance curves of two piezoelectric transducers with different frequencies in air; FIG. 3 is a graph illustrating electrical impedance curves of two piezoelectric transducers of different frequencies in water; FIG. 4 is a graph illustrating the electrical impedance of two piezoelectric transducers of different frequencies in alcohol; fig. 5 is a graph of the electrical impedance of two piezoelectric transducers of different frequencies in castor oil.
According to the above, in an exemplary embodiment, the method further includes: recording the electrical impedance obtained after the piezoelectric transducer is contacted with or immersed in the liquid to be measured as actual measured electrical impedance; and acquiring a reference electrical impedance of the corresponding piezoelectric transducer, comparing the actual measured electrical impedance with the reference electrical impedance, and determining the impedance error of the piezoelectric transducer. Specifically, as shown in tables 1 and 2.
TABLE 1 resonance frequency drift and impedance parameters in various test fluids
Figure BDA0003556855950000071
Figure BDA0003556855950000081
TABLE 2 comparison of actual measured and reference acoustic impedances
Figure BDA0003556855950000082
In summary, the present invention provides a liquid component detection method, which includes first obtaining a liquid to be detected in a target container; then contacting a piezoelectric transducer target container, or contacting the piezoelectric transducer with liquid to be detected, or immersing the piezoelectric transducer in the liquid to be detected, and electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer; and calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and determining the liquid components in the liquid to be detected according to the acoustic impedance. Therefore, the method comprises the steps of contacting a piezoelectric transducer target container, or contacting the piezoelectric transducer with liquid to be detected, or immersing the piezoelectric transducer in the liquid to be detected, then electrifying the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be detected according to the electrical impedance of the piezoelectric transducer, wherein in acoustics, the acoustic impedance is a key inherent characteristic of the liquid, and each liquid has only one unique acoustic impedance at a specific temperature. When the method needs to detect the liquid component of the liquid to be detected, the piezoelectric transducer is only needed to be contacted with or immersed in the liquid to be detected, then the piezoelectric transducer is electrified to detect the electrical impedance of the piezoelectric transducer, meanwhile, the acoustic impedance corresponding to the liquid to be detected can be obtained according to the predetermined model relation between the electrical impedance and the acoustic impedance, and finally, the corresponding liquid substance can be found out by referring to the existing liquid acoustic impedance standard, so that the liquid component in the liquid to be detected can be obtained. The method can determine the liquid components in the liquid to be detected only by utilizing the piezoelectric transducer, has low detection cost, short detection time and high detection efficiency, and simultaneously, the whole detection equipment is portable and easy to carry.
Referring to fig. 6, the present embodiment provides a liquid component detecting system, which includes:
and the power supply module M10 is used for electrifying the piezoelectric transducer after the piezoelectric transducer is contacted with or immersed in the liquid to be measured in the target container or the piezoelectric transducer is contacted with the target container. Specifically, the liquid to be measured in this embodiment includes, but is not limited to: the liquid to be detected can be determined according to actual conditions. Meanwhile, the target container is a container used in cooperation with the liquid to be measured, and the target container can be selected according to some physical characteristics of the liquid to be measured, for example, if the liquid to be measured is corrosive, some containers with an anti-corrosion function can be selected as the target container. As an example, in this embodiment, the piezoelectric transducer may be immersed in a half of the liquid to be measured, then the piezoelectric transducer is powered by an external power source, and finally the electrical impedance of the piezoelectric transducer after being powered is detected. As another example, in this embodiment, the piezoelectric transducer may be first contacted with the target container, then an external power source is used to energize the piezoelectric transducer, and finally the electrical impedance of the energized piezoelectric transducer is detected. As yet another example, the present embodiment may be such that immediately after the piezoelectric transducer is brought into contact with the target container, the piezoelectric transducer is then energized using an external power source, and finally the electrical impedance of the piezoelectric transducer after the energization is detected.
The electrical impedance acquisition module M20 is used for acquiring the electrical impedance of the piezoelectric transducer after being electrified;
the acoustic impedance calculation module M30 is used for calculating the acoustic impedance of the liquid to be measured according to the electrical impedance of the piezoelectric transducer;
and the liquid component detection module M40 is used for determining the liquid components in the liquid to be detected according to the acoustic impedance.
Specifically, the process of calculating the acoustic impedance of the liquid to be measured by the acoustic impedance calculation module M30 based on the electrical impedance of the piezoelectric transducer includes: obtaining a pre-established model relation between the electrical impedance of the piezoelectric transducer and the acoustic impedance of a liquid substance, combining the model relation with the electrical impedance of the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be measured, wherein the model relation comprises the following steps:
Figure 3
Figure BDA0003556855950000101
Figure BDA0003556855950000102
Figure BDA0003556855950000103
Figure BDA0003556855950000104
Figure BDA0003556855950000105
in the formula, C 0 A static capacitance per unit area representing the piezoelectric plate;
c 33 represents the effective elastic constant;
e 33 represents a piezoelectric constant;
ε 33 represents a dielectric constant;
ρ represents the density of the piezoelectric material;
ω represents angular velocity;
Z PZT represents the electrical impedance of the piezoelectric transducer;
Z L representing the acoustic impedance of the liquid to be measured;
i represents an imaginary number;
h represents the half thickness of the piezoelectric transducer;
s denotes the area of the piezoelectric transducer.
According to the above, in an exemplary embodiment, the method further includes: and acquiring the electrical impedance amplitude of the piezoelectric transducer under the anti-resonance frequency, and calculating the acoustic impedance of the liquid to be measured based on the electrical impedance amplitude of the piezoelectric transducer. In this embodiment, since the electrical impedance of the piezoelectric transducer is the largest at the anti-resonance frequency, the electrical impedance amplitude of the piezoelectric transducer at the anti-resonance frequency is obtained at this time, and then the acoustic impedance of the liquid to be measured calculated based on the electrical impedance amplitude of the piezoelectric transducer at this time is the highest accuracy, which is equivalent to the highest accuracy of the acoustic impedance of the liquid to be measured obtained according to the electrical impedance amplitude of the piezoelectric transducer.
In accordance with the above, in an exemplary embodiment, the system further comprises: contacting or immersing piezoelectric transducers with different frequencies with the same liquid to be measured, and acquiring the electrical impedance amplitude of the piezoelectric transducers under each frequency; and determining the relation between the electrical impedance amplitude and the frequency of the piezoelectric transducer according to the electrical impedance amplitude of the piezoelectric transducer at each frequency. Specifically, as can be seen from fig. 2 to 5, the larger the frequency of the piezoelectric transducer, the smaller the magnitude of the electrical impedance in the same liquid to be measured. Wherein, fig. 2 is a graph illustrating the electrical impedance curves of two piezoelectric transducers with different frequencies in air; FIG. 3 is a graph illustrating electrical impedance curves of two piezoelectric transducers of different frequencies in water; FIG. 4 is a graph illustrating the electrical impedance of two piezoelectric transducers of different frequencies in alcohol; fig. 5 is a graph of the electrical impedance of two piezoelectric transducers of different frequencies in castor oil.
In accordance with the above, in an exemplary embodiment, the system further comprises: recording the electrical impedance obtained after the piezoelectric transducer is contacted with or immersed in the liquid to be measured as actual measured electrical impedance; and acquiring a reference electrical impedance of the corresponding piezoelectric transducer, comparing the actual measured electrical impedance with the reference electrical impedance, and determining the impedance error of the piezoelectric transducer. Specifically, as shown in tables 3 and 4.
TABLE 3 resonance frequency shift and impedance parameters in various test fluids
Figure BDA0003556855950000111
TABLE 4 comparison Table of actual measured and reference acoustic impedances
Figure BDA0003556855950000112
Figure BDA0003556855950000121
In summary, the present invention provides a liquid component detecting system, which first obtains a liquid to be detected in a target container; then contacting a piezoelectric transducer target container, or contacting the piezoelectric transducer with liquid to be detected, or immersing the piezoelectric transducer in the liquid to be detected, and electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer; and calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and determining the liquid components in the liquid to be detected according to the acoustic impedance. Therefore, the system can find out the corresponding liquid substance by contacting the piezoelectric transducer target container, or contacting the piezoelectric transducer with the liquid to be detected, or immersing the piezoelectric transducer in the liquid to be detected, then electrifying the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be detected according to the electrical impedance of the piezoelectric transducer, wherein in acoustics, the acoustic impedance is a key inherent characteristic of the liquid, and each liquid has only unique acoustic impedance at a specific temperature, so that the system can find out the corresponding liquid substance by detecting the acoustic impedance of the liquid to be detected and then referring to the existing liquid acoustic impedance standard, thereby obtaining the liquid component in the liquid to be detected. When the system needs to detect the liquid component of the liquid to be detected, the piezoelectric transducer is only needed to be contacted with or immersed in the liquid to be detected, then the piezoelectric transducer is electrified to detect the electrical impedance of the piezoelectric transducer, meanwhile, the acoustic impedance corresponding to the liquid to be detected can be obtained according to the predetermined model relation between the electrical impedance and the acoustic impedance, and finally, the corresponding liquid substance can be found out by referring to the existing liquid acoustic impedance standard, so that the liquid component in the liquid to be detected can be obtained. The system can determine the liquid components in the liquid to be detected only by utilizing the piezoelectric transducer, so that the detection cost is low, the detection time is short, the detection efficiency is high, and meanwhile, the whole detection equipment is portable and easy to carry. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
Referring to fig. 7, the present embodiment further provides a liquid component detecting apparatus, including:
the piezoelectric transducer 100 is used for contacting with liquid to be measured, or contacting with a container containing the liquid to be measured, or immersing in the liquid to be measured; by way of example, the liquids to be measured in the present embodiment include, but are not limited to: water, alcohol, castor oil, and other liquid substances, and the specific liquid to be measured may be determined according to actual conditions, and this embodiment is not limited to specific categories. Meanwhile, the container for containing the liquid to be detected (referred to as a target container for short) refers to a container used in cooperation with the liquid to be detected, the target container can be selected according to some physical characteristics of the liquid to be detected, for example, the liquid to be detected has corrosivity, and then some containers with an anti-corrosion function can be selected to contain the liquid to be detected.
The power supply 200 is connected with the piezoelectric transducer and used for supplying power to the piezoelectric transducer;
and an impedance converter 300 connected to the piezoelectric transducer for converting the electrical impedance of the piezoelectric transducer to the acoustic impedance of the liquid to be measured. As an example, the impedance converter in the present embodiment may be selected from existing converters in which an impedance conversion relationship is previously set. As another example, the impedance converter in this embodiment may be adjusted by the inspector, for example, the inspector may select a conventional computing chip and then load the existing computing model for converting the electrical impedance into the acoustic impedance into the computing chip in a conventional manner. Therefore, in this embodiment, no limitation is imposed on the hardware acquisition mode or the specific internal structure of the impedance converter, and the inspector may select the existing converter or a converter loaded into the existing calculation model by himself.
And the display 400 is connected with the impedance converter and is used for displaying the acoustic impedance of the liquid to be measured. The display in this embodiment may be an independent display or a non-independent display. For example, a separate PC display may be used, and a display in another component (e.g., an electrical parameter detector) may be used as a display for displaying the acoustic impedance of the liquid to be measured.
In an exemplary embodiment, the liquid composition detection apparatus further comprises an electrical parameter detector 500 connected to the piezoelectric transducer for detecting and displaying an electrical impedance of the piezoelectric transducer; alternatively, the electrical parameter detector 500 may be used to detect and display electrical parameters of the piezoelectric transducer, such as voltage parameters, current parameters, etc., and the electrical impedance of the piezoelectric transducer may be directly calculated by detecting the electrical parameters by a human. The electrical parameter detector 500 in the present embodiment may be an existing electrical impedance analyzer, such as an electrical impedance analyzer with model number agilent 4294A. As an example, in this embodiment, a piezoelectric transducer is immersed in a liquid substance to be measured by half, then the power supply 200 is used to energize the piezoelectric transducer, and finally the electrical parameter detector 500 is used to detect the electrical impedance of the energized piezoelectric transducer. As another example, in this embodiment, after the piezoelectric transducer is first contacted with the target container, an external power source is used to energize the piezoelectric transducer, and finally the electrical parameter detector 500 is used to detect the electrical impedance of the energized piezoelectric transducer. As yet another example, the present embodiment may employ an external power source to energize the piezoelectric transducer immediately after it is in contact with the target container, and finally detect the electrical impedance of the piezoelectric transducer after energization using the electrical parameter detector 500.
In an exemplary embodiment, a piezoelectric transducer includes two oppositely disposed piezoelectric plates, and a surface of each piezoelectric plate is plated with a nickel electrode. The embodiment can ensure that the piezoelectric transducer is prevented from short circuit when each piezoelectric plate is contacted with or immersed in the liquid to be measured by plating the nickel electrode on the surface of each piezoelectric plate. Specifically, the piezoelectric plate in the present embodiment may employ an existing piezoelectric plate, for example, an existing piezoelectric plate made of lead zirconate titanate and epoxy resin.
In an exemplary embodiment, the piezoelectric plate in the piezoelectric transducer is circular. The embodiment can obtain two circularly opposite piezoelectric transducers by arranging the piezoelectric plates in a circular shape, and the two circularly opposite piezoelectric plates are arranged in the circular grooves of the white plastic and then sealed by waterproof glue to form the air gasket. Not only can the sensitivity of the sensor be improved by the air backing, but ultrasonic scattering in the white housing can also be prevented.
In an exemplary embodiment, a sound absorption block is arranged on an inner wall of a container for containing liquid to be detected, and the sound absorption block is in a sawtooth wave shape on the inner wall of the container. Through set up the sound absorption piece on inside the container, can utilize the sound absorption piece to eliminate the reflection of ultrasonic when detecting the liquid that awaits measuring, improve and detect the rate of accuracy. The sound absorption block made of the sound absorption material in the present embodiment may be, for example, an existing sound absorption block made of vulcanized silicone rubber.
In summary, the present invention provides a liquid component detecting apparatus, which first obtains a liquid substance to be detected and a target container for containing the liquid substance to be detected; then contacting the piezoelectric transducer with a target container, or contacting the piezoelectric transducer with a liquid substance to be detected, or immersing the piezoelectric transducer in the liquid substance to be detected; electrifying the piezoelectric transducer by a power supply, and then acquiring the electrical impedance of the piezoelectric transducer; and finally, converting the electrical impedance of the piezoelectric transducer into the acoustic impedance of the liquid to be measured by utilizing the existing impedance converter. In acoustics, acoustic impedance is a key inherent characteristic of liquid, and each liquid only has unique acoustic impedance, so that the corresponding liquid substance can be found out by detecting the acoustic impedance of the liquid to be detected and referring to the existing liquid acoustic impedance standard, and liquid components in the liquid substance to be detected can be obtained. The liquid component detection device can determine the liquid component in the liquid substance to be detected only by utilizing the piezoelectric transducer, not only has low detection cost, but also has short detection time and high detection efficiency, and meanwhile, the whole liquid component detection device has simple structure, is portable and easy to carry. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
The structures, proportions, and dimensions shown in the drawings and described in the specification are for illustrative purposes only and are not intended to limit the scope of the present invention, which is defined by the claims, but rather by the claims, and are not intended to limit the scope of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.
It should be understood that although the terms first, second, third, etc. may be used to describe preset ranges, etc. in embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, the first preset range may also be referred to as a second preset range, and similarly, the second preset range may also be referred to as the first preset range, without departing from the scope of the embodiments of the present invention.

Claims (10)

1. A method for detecting a component of a liquid, the method comprising the steps of:
obtaining liquid to be measured in a target container;
contacting a piezoelectric transducer with the target container, or contacting or immersing a piezoelectric transducer with the liquid to be measured;
electrifying the piezoelectric transducer to obtain the electrical impedance of the piezoelectric transducer;
and calculating the acoustic impedance of the liquid to be detected based on the electrical impedance of the piezoelectric transducer, and determining the liquid components in the liquid to be detected according to the acoustic impedance.
2. The liquid component detection method according to claim 1, characterized by further comprising: and acquiring the electrical impedance amplitude of the piezoelectric transducer under the anti-resonance frequency, and calculating the acoustic impedance of the liquid to be measured based on the electrical impedance amplitude of the piezoelectric transducer.
3. The liquid component detection method according to claim 1 or 2, wherein the process of calculating the acoustic impedance of the liquid to be measured based on the electrical impedance of the piezoelectric transducer comprises:
obtaining a pre-established model relation between the electrical impedance of the piezoelectric transducer and the acoustic impedance of a liquid substance, combining the model relation with the electrical impedance of the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be measured, wherein the model relation comprises the following steps:
Figure FDA0003556855940000011
Figure FDA0003556855940000012
Figure FDA0003556855940000013
Figure FDA0003556855940000014
Figure FDA0003556855940000015
Figure FDA0003556855940000021
in the formula, C 0 A static capacitance per unit area representing the piezoelectric plate;
c 33 represents the effective elastic constant;
e 33 represents a piezoelectric constant;
ε 33 represents a dielectric constant;
ρ represents the density of the piezoelectric material;
ω represents the angular velocity;
Z PZT represents the electrical impedance of the piezoelectric transducer;
Z L representing the acoustic impedance of the liquid to be measured;
i represents an imaginary number;
h represents the half thickness of the piezoelectric transducer;
s denotes the area of the piezoelectric transducer.
4. The liquid component detection method according to claim 1, characterized by further comprising:
contacting or immersing piezoelectric transducers with different frequencies with the same liquid to be measured, and acquiring the electrical impedance amplitude of the piezoelectric transducers under each frequency;
and determining the relation between the electrical impedance amplitude and the frequency of the piezoelectric transducer according to the electrical impedance amplitude of the piezoelectric transducer at each frequency.
5. The liquid component detection method according to claim 1, characterized by further comprising:
recording the electrical impedance obtained after the piezoelectric transducer is contacted with or immersed in the liquid to be measured as actual measured electrical impedance;
and acquiring reference electrical impedance of the corresponding piezoelectric transducer, and comparing the actual measured electrical impedance with the reference electrical impedance to determine the impedance error of the piezoelectric transducer.
6. The liquid component detection method according to claim 1 or 2, wherein the liquid to be measured includes: water, alcohol, castor oil.
7. A liquid composition detection system, said system comprising:
the power supply module is used for electrifying the piezoelectric transducer after the piezoelectric transducer is contacted with or immersed in liquid to be measured in a target container or the piezoelectric transducer is contacted with the target container;
the electrical impedance acquisition module is used for acquiring the electrical impedance of the piezoelectric transducer after electrification;
the acoustic impedance calculation module is used for calculating the acoustic impedance of the liquid to be measured according to the electrical impedance of the piezoelectric transducer;
and the liquid component detection module is used for determining the liquid components in the liquid to be detected according to the acoustic impedance.
8. The liquid composition detection system of claim 1, wherein the electrical impedance acquisition module further comprises obtaining an electrical impedance magnitude of the piezoelectric transducer at an anti-resonance frequency; the acoustic impedance calculation module further calculates the acoustic impedance of the liquid to be measured according to the electrical impedance amplitude of the piezoelectric transducer.
9. The liquid component detecting system according to claim 7 or 8, wherein the process of calculating the acoustic impedance of the liquid to be measured by the acoustic impedance calculating module according to the electrical impedance of the piezoelectric transducer comprises:
obtaining a pre-established model relation between the electrical impedance of the piezoelectric transducer and the acoustic impedance of a liquid substance, combining the model relation with the electrical impedance of the piezoelectric transducer, and calculating the acoustic impedance of the liquid to be measured, wherein the model relation comprises the following steps:
Figure FDA0003556855940000031
Figure FDA0003556855940000032
Figure FDA0003556855940000033
Figure FDA0003556855940000034
Figure FDA0003556855940000035
Figure FDA0003556855940000041
in the formula, C 0 A static capacitance per unit area representing the piezoelectric plate;
c 33 represents the effective elastic constant;
e 33 represents a piezoelectric constant;
ε 33 represents a dielectric constant;
ρ represents the density of the piezoelectric material;
ω represents the angular velocity;
Z PZT represents the electrical impedance of the piezoelectric transducer;
Z L representing the acoustic impedance of the liquid to be measured;
i represents an imaginary number;
h represents the half thickness of the piezoelectric transducer;
s denotes the area of the piezoelectric transducer.
10. The liquid component detection system according to claim 7 or 8, wherein the liquid to be measured includes: water, alcohol, castor oil.
CN202210280313.1A 2022-03-21 2022-03-21 Liquid component detection method and system Pending CN114813932A (en)

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