KR101040527B1 - Sensor for detecting liquid state and sesnsing method using the same - Google Patents

Abstract

The present invention relates to a liquid state measuring sensor for detecting a state change in a liquid by contacting the liquid and measuring the state information of the liquid in real time, and a liquid state detecting method using the same. It is possible to adsorb polarized impurities generated due to changes in environmental factors, such as chemical reactions, deterioration, impurity inflow, and decrease in the amount of liquid. Characterized in that it is possible to detect a change in the state information in the. In this case, the amount of change in the electrical characteristics of the sensing film due to the electric field is changed differently. In this case, the data of the reference sensor are secured to compensate for the change in the state of the liquid with respect to the temperature, thereby making it possible to make accurate measurements without errors. To provide.

Liquid, state, sensor, electrode, sensor

Description

Sensor for detecting liquid state and method for detecting liquid state using the same {Sensor for detecting liquid state and sesnsing method using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a sensor for detecting state information in contact with a liquid and a measuring device for detecting a state change in a liquid in real time, and particularly, a strong adsorption to polar molecules or ionic substances on a predetermined substrate. Liquid state sensor comprising a sensing film having a property, a predetermined electrode for measuring the electrical conductivity of the sensing film, and a voltage applying electrode for applying an electric field to the side of the sensing film and a liquid state sensing method using the same Related to.

The present invention relates to a liquid state sensor for checking liquid state information in real time and a liquid state detection method using the same. The purpose of the liquid state detection is to allow the user to more easily determine the state information of the liquid to change the state of the liquid. It is to prevent the damage of related other machinery and mechanisms that occur and to maintain normal operation.

However, in the conventional liquid state sensor, it is difficult to accurately determine the state information of the liquid, or only a sensor of a simple switch concept for measuring single information has been used.

That is, the conventional conventional liquid state sensor and the measurement method of the state information for detecting the state change in the liquid has been uncomfortable because it is difficult to determine only the simple information or the various types of liquids, and it is difficult to measure in real time for various state changes of the liquid. there was.

In addition, the failure to judge and manage the liquid state information due to such real-time measurement difficulty has resulted in damage and malfunction of related machinery or apparatus.

However, in the ubiquitous era, it is necessary to secure various information on the liquid properties inside the device through the optimized liquid state sensor. Accordingly, the necessity of a sensor that can make a more accurate judgment on various changes in liquid information is required. have.

The first object of the present invention proposed to solve the above-mentioned problems is to provide a liquid state sensor that can reduce the size of the sensor and simplify the structure by optimizing the liquid state sensor.

The second purpose is to apply the liquid state sensor to accurately determine the state of the liquid and to provide the convenience of optimal management and maintenance of other equipment to which various kinds of liquid state information are applied. It is configured to enable real-time measurement of liquid state information even in a real time situation.

The third purpose is to change the amount of change in the electrical characteristics of the sensing film due to the application of an electric field, depending on the external environmental influence-the type and state of the liquid (chemical reaction, temperature, deterioration or impurity-containing state), in which case the data of the reference sensor By compensating for the change in the state of the liquid with respect to the temperature it is possible to achieve a relatively accurate measurement without errors.

The fourth object is to further improve the sensitivity of the sensor measured by adding a heating device to the substrate portion of the liquid sensor in order to solve the problem of deterioration of sensitivity due to low temperature operation to operate the liquid sensor at a constant temperature. To increase the measurement error.

The liquid-state measuring sensor configuration for solving the above-mentioned conventional problems and achieving the object according to the present invention includes a sensing film installed on the upper surface of the substrate and having a strong adsorption property against polar molecules or ionic materials, and both sides of the sensing film. An electrode for measuring electrical conductivity; And a voltage application electrode provided to apply an electric field at predetermined intervals on the side of the sensing film, wherein the impurity and ionic material composed of polarizable molecules in the liquid are adsorbed to the sensing film according to the application of the electric field. It is characterized by measuring the state of the liquid by sensing the amount of change in electrical properties by inducing.

Here, the substrate is characterized by consisting of any one selected from a glass substrate, silicon substrate, alumina sintered substrate.

In addition, the sensing film is composed of any one of activated carbon, activated carbon fiber, carbon aerogel, carbon nanofiber, and carbon nanotube, and is characterized in that the polarized impurities are strongly adsorbed / stored by an electric field in the liquid.

In addition, the heating device is further configured on the substrate to increase the sensitivity of the sensing film, the heating device is characterized in that the nichrome wire or platinum, the heating temperature range is set to operate at 50 ℃ to 200 ℃. .

In addition, in the liquid state sensing method, when the electrical conductivity (Rbias) and the voltage is not applied when a predetermined voltage is applied to both the electrode attached to the sensing film and the voltage applying electrode formed on the side of the sensing film. It is characterized by determining the state information of the liquid by measuring the difference (ΔR = | Rbias-Ro |) of the electrical conductivity Ro of the liquid crystal.

Here, the measured difference in electrical conductivity Ro (ΔR = | Rbias-Ro |) is 0.1μm ~ the distance between both ends of one electrode attached to the sensing film and the voltage application electrode formed on the side of the sensing film. It is characterized by selecting and measuring in the range of 10mm.

In addition, the measured electrical conductivity ΔR is proportionally changed according to the magnitude of the voltage applied between the two electrodes, and the power used for constructing the electric field between the two electrodes uses any one selected from DC or AC. It is characterized by.

Here, the voltage of the power supply is characterized in that applied in the range of 1V to 220V.

When the sensor is immersed in the liquid, a change in electrical conductivity ΔR measured by the applied electric field is generated, and the change in electrical conductivity ΔR measured by the electric field measured in air in which the sensor is not in contact with the liquid. Is characterized in that it implements a level switch function that measures the critical flow rate of the liquid using little characteristics.

As described above, when detecting the liquid state through the liquid state measurement sensor according to the present invention can determine the state of the liquid by measuring the state of the liquid in real time by checking the electrical characteristics of the sensor for each kind and characteristic of the same type of liquid only Provide the effect.

In addition, the amount of change in the electrical characteristics of the sensing film due to the application of an electric field varies depending on the external environmental influence-type and state of the liquid (chemical reaction, temperature, deterioration or impurity-containing state). By compensating for the change in the state of the liquid, it provides the effect of making an accurate measurement without errors.

Accordingly, it is possible to prevent abnormal occurrence of mechanical and mechanical devices to be measured, thereby increasing device durability and improving management efficiency.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention.

1 is a structural diagram showing a first embodiment of a state sensor for measuring a state of a liquid, FIG. 2 is a structural diagram showing a second embodiment of a state sensor for measuring a state of a liquid, and FIG. 4 is a structural diagram showing a structure including a cross-sectional structure-heating device of a state sensor for measuring the state of a liquid, FIG. 5 is a graph confirming a temperature dependency characteristic of a sensing film, and FIG. Is a graph showing the results of measuring engine oil using a sensor made of carbon nanofibers among various fabricated sensing film materials, and FIG. 7 is a sensor made of carbon nanofibers from various fabricating sensing film materials. Graph showing the results of measuring ultrapure water and general purified water, FIG. 8 shows palm oil using a sensor made of carbon nanofibers among various fabrication materials Shows a graph of the results, Fig. 9 is a graph showing the temperature dependence of the electrical conductivity sensing film (ΔR) is caused by the applied electric field relative to the temperature change.

First, a liquid state sensor according to the present invention will be described with reference to FIG. 1.

The state sensor for measuring the state information of the liquid is configured to measure polarizable impurities and ions in the liquid when the sensing film 310 formed on a predetermined area on the substrate 300 is in contact with the liquid. Electrodes 320 for measuring the electrical conductivity of the sensing layer 310 are configured on both sides.

In addition, a voltage applying electrode 330 for applying an electric field to the side of the sensing film 310 is configured to have a predetermined voltage across one of the electrodes 320 and the voltage applying electrode 330 for electric conductivity measurement. It is applied to measure the electrical conductivity of the sensing film 310 is changed by the polar impurities and ions adsorbed to the sensing film 310 to check the state information in the liquid.

2 is a structural diagram showing a second embodiment of a state sensor for measuring the state of a liquid. As shown, another configuration of the state sensor is configured to configure the voltage applying electrode 330 used in the first embodiment at predetermined intervals on the left and right sides of the sensing film 310 of the state sensor unit. By applying a predetermined voltage to the two voltage applying electrodes 330, the electrical conductivity of the sensing film 310, which is changed by polarized impurities and ions adsorbed to the sensing film 310, is measured using the electrode 320. It is possible to check the status information in the system.

3 is a structural diagram showing a cross-sectional structure of the sensor of the liquid state sensor-electrode structure.

1 to 2 is a state sensor for measuring the state of the liquid used in the electrode, the electrode and the substrate is applied to the sensing layer for absorbing / storing the polar impurities and ions in the liquid by the electric field, And mounting a voltage applying electrode for applying the formed sensing film and the electric field.

The structure and size of the substrate 300, the sensing layer 310, and the electrodes 320 and 330 shown and described herein are not limited thereto, and various modifications may be made.

4 is a structural diagram showing a configuration including a cross-sectional structure-heating device of a state sensor for measuring the state of a liquid.

In this case, the heat generator 350 is made of a metal such as nichrome wire or platinum, the heat generation temperature range is preferably set to operate at 50 ℃ to 200 ℃.

More preferably, it is configured to be controlled by a temperature sensor to measure the state in a certain temperature range when measuring the state information of the liquid.

Here, the substrate 300 of the device is a glass substrate, a silicon substrate and an alumina sintered substrate and the like are used.

The electrodes 320 and 330 may be manufactured using deposition equipment such as an E-beam or a sputter through a shadow mask, or may be manufactured by screen printing through Ag or other metal paste.

The sensing layer 310 is formed by a screen printing method through a paste in which a sensing material powder and a binder are mixed. In addition, the sensing layer 310 formed by the screen printing method on the substrate 300 is connected across the electrodes. The device fabricated as described above allows the sensing film 310 to be in contact with the liquid, and connects a power source to the electrode for voltage application and the electrode of the sensing film 310 to apply an electric field, and to sense the sensing film 310. The change in the electrical conductivity ΔR generated by the adsorption / storage of polarizable impurities and ions in the liquid can be measured.

In this case, the amount of change in the electrical characteristics of the sensing film 310 is changed by applying an electric field. In this case, the data of the reference sensor is secured to compensate for the change in the state of the liquid with respect to the temperature, thereby making accurate measurement without any error. It can be achieved.

5 is a graph illustrating the temperature dependency characteristic of the sensing layer 310.

Tables 1 to 9 show measurement values of resistance values and electric field changes when the applied voltages are varied for various liquids.

Referring to the graph of FIG. 5, a sensor (made of carbon nanofibers) (a package of the front surface of the sensor that suppresses external and non-temperature reactions) is measured as an example. As can be seen from the graph, it can be seen that the electrical conductivity increases with increasing temperature.

Sensing sensitivity of the liquid state sensor including the carbon nanofiber sensing film depends on the temperature, the sensing sensitivity of the sensor is less electrical conductivity with increasing temperature when the temperature range of the liquid to be measured is 70 ℃ at room temperature Although proportionally increased within the range, it can be seen that the electrical conductivity is significantly increased when the temperature of the liquid to be measured is 70 ℃ or more.

As described above, the conductance of the carbon nanotubes is greatly increased at a temperature of 70 ° C. or more. The reason is that the electrical conductivity changes according to the adsorption of molecules or ions while supplying sufficient active energy to the adsorption capacity of the sensing material, thereby activating the mobility of molecules or ions. Judging by its characteristics. Therefore, when the temperature range of the liquid to be measured through the sensing film is room temperature or low temperature, the sensing device may be improved because the heating device is mounted on the substrate to improve the adsorption capacity of the sensing material.

In this case, the heating device 350 installed on the substrate is preferably composed of nichrome wire or platinum, and the heat generation temperature range is more preferably set to operate at 50 ° C to 200 ° C.

On the other hand, in real-time measurement of the state information of the liquid, the state sensor displays the state information of the liquid by using the characteristic that the change in the electrical conductivity (ΔR) measured by the liquid varies by liquid upon application of the electric field. can do. The characteristics of the electric conductivity change due to the electric field application effect of the state sensor can be seen in FIGS. 6 to 8.

In addition, the measured difference in electrical conductivity (ΔR = | Rbias-Ro |) is a distance interval between the both ends of one electrode attached to the sensing film and the voltage applying electrode configured on the side of the sensing film in the range of 0.1 μm to 10 mm. It is desirable to select and measure.

On the other hand, the power used to configure the electric field between the two electrodes using any one selected from direct current or alternating current so that the electrical conductivity (ΔR) measured in accordance with the magnitude of the voltage applied between the two electrodes to be proportionally changed.

In this case, the voltage of the power supply is preferably applied in the range of 1V to 220V.

When the sensor is immersed in the liquid, the sensor generates a change in electrical conductivity ΔR measured by an applied electric field, and the sensor has almost no change in measured electrical conductivity ΔR in air which is not in contact with the liquid. It is also possible to implement a level switch function that measures the critical flow rate of the liquid.

FIG. 6 is a result of measuring engine oil using a sensor made of carbon nanofibers among various fabricated sensing film materials. The change in the electrical conductivity ΔR of the sensing film generated through application of a predetermined electric field in the engine oil may be confirmed to represent a characteristic in which the change in the sensing value is large in the used oil.

(Table 1: Electric conductivity difference according to electric field change at room temperature of brake oil (ΔR))

division R1. [Ω] (0V) R1. [Ω] (3V) ΔR RES. [Ω] Rate One 190,300 18,610 10.226

Table 2: Difference in Electrical Conductivity (ΔR) According to the Electric Field Change of Engine Oil New Room Temperature

Applied voltage RES. [Ω] Amount of change 0 V 921,000 3 V 920,000 1,000 6 V 919,000 1,000 9 V 918,000 1,000 12 V 916,000 2,000

Table 3: Difference in Electrical Conductivity (ΔR) According to Electric Field Change of Engine Oil New High Temperature)

Applied voltage RES. [Ω] Amount of change 0 V 815,000 3 V 807,000 8,000 6 V 800,000 7,000 9 V 792,000 8,000 12 V 784,000 8,000

(Table 4: Electrical conductivity difference (ΔR) according to the electric field change at room temperature of engine oil 5000Km)

Applied voltage RES. [Ω] Amount of change 0 V 938,000 3 V 937,000 1,000 6 V 936,000 1,000 9 V 935,000 1,000 12 V 934,000 1,000

(Table 5) Electric conductivity difference according to the change of electric field of engine oil 5000Km high temperature (ΔR)

Applied voltage RES. [Ω] Amount of change 0 V 790,000 3 V 777,000 13,000 6 V 763,000 14,000 9 V 748,000 15,000 12 V 731,000 17,000

FIG. 6 is a result of measuring engine oil using a sensor made of carbon nanofibers among various fabricated sensing film materials. It can be seen that the change in the sensing value is large in the oil in which the change in the electrical conductivity ΔR of the sensing film generated by applying a predetermined electric field in the engine oil is used.

7 is a result of measuring ultrapure water and general purified water using a sensor made of carbon nanofibers among various fabrication of sensing film materials. Ultrapure water has a small amount of general purified water compared to the characteristics of no impurities or ions in the liquid, but changes in the electrical conductivity (ΔR) of the sensing film generated by applying a predetermined electric field according to the amount of ions contained therein. It can be seen that the change in the sensed value is large in general purified water.

(Table 6: Electrical conductivity difference according to the application of electric field at room temperature (ΔR))

division Applied voltage R. [Ω] Electric field change amount [Ω] One 0 553,000 3 V 573,000 20,000

Table 7: Difference in Electrical Conductivity (ΔR) According to Electric Field Application at High Temperature

division Applied voltage R. [Ω] Electric field change amount [Ω] One 0 656,000 3 V 731,994 75,994

8 is a result of measuring palm oil using a sensor made of carbon nanofibers among various fabricated sensing film materials. It can be seen that the change in the electrical conductivity ΔR of the sensing film generated by applying a predetermined electric field in palm oil is different depending on the use temperature. The sensor used was the same, and the graph x-axis is the data measured according to the change of temperature (80, 120, 170 ℃), and the higher the change in temperature, the higher the change in sensing value.

Table 8: Difference in Electrical Conductivity (ΔR) According to Application of Electric Field at Soybean Oil Room Temperature)

division Applied voltage R. [Ω] Electric field change amount [Ω] One 0 835,000 3 V 837,000 2,000

(Table 9: Electrical conductivity difference (ΔR) according to application of soybean oil high temperature electric field)

division Applied voltage R. [Ω] Electric field change amount [Ω] One 0 915,000 3 V 922,000 7,000

9 is a result showing the temperature dependence of the electrical conductivity ΔR of the sensing film generated by applying an electric field to the temperature change. In the liquid state sensor, the change in the electrical conductivity (ΔR) due to the application of an electric field is different with respect to the temperature change, which occurs at a constant rate with respect to the temperature depending on the material of the sensing film. Status information can be corrected.

As described above, various embodiments according to the present invention have been described with reference to the accompanying tables, graphs and drawings, but it is obvious that the technical scope of the present invention is not limited to the above-described matters.

In other words, according to the technical spirit of the present invention can not be specifically limited to the specific embodiments as described above and the accompanying drawings, various modifications within the scope similar to the technical spirit of the claims of this patent belong to this patent. You will be able to

1 is a structural diagram showing a first embodiment of a state sensor unit for measuring the state of a liquid

  2 is a structural diagram showing a second embodiment of a state sensor unit for measuring the state of a liquid

3 is a structural diagram showing a cross-sectional structure of the sensor unit of the liquid state sensor-electrode structure configuration;

4 is a structural diagram showing a configuration including a cross-sectional structure of the state sensor unit for measuring the state of the liquid-heating device

5 is a graph confirming the temperature dependency characteristic of the sensing film

6 is a graph showing the results of measuring engine oil using a sensor made of carbon nanofibers among various fabricated sensing film materials.

7 is a graph showing the results of measuring ultrapure water and general purified water using a sensor made of carbon nanofibers among various fabricated sensing film materials.

8 is a graph showing the results of measuring palm oil using a sensor made of carbon nanofibers among various fabricated sensing film materials.

9 is a graph showing the temperature dependence of the electrical conductivity (ΔR) of the sensing film generated by applying an electric field to the temperature change.

*** Description of the main parts of the drawing ***

300: substrate 310: sensing film

320: electrode 330: electrode for electric field

350: heating device

Claims (9)

In the liquid state measurement sensor for measuring the liquid state and physical properties, A sensing film installed on the upper surface of the substrate and having a strong adsorption property to polar molecules or ionic materials; Electrodes for measuring electrical conductivity on both sides of the sensing film; And And a voltage application electrode provided to apply an electric field at predetermined intervals on the side of the sensing film. Liquid state measurement sensor, characterized in that by measuring the amount of change in electrical properties by inducing adsorption of impurities and ionic substances consisting of polarizable molecules in the liquid to the sensing membrane in accordance with the electric field applied The method of claim 1, The substrate is a liquid state measurement sensor, characterized in that composed of any one selected from a glass substrate, silicon substrate, alumina sintered substrate 3. The method of claim 2, The sensing film is composed of any one of activated carbon, activated carbon fiber, carbon aerogel, carbon nanofiber, and carbon nanotube, and is a liquid state measuring sensor which strongly adsorbs / stores polarizable impurities by an electric field in a liquid. The method of claim 3, A heating device is further configured on the substrate in order to increase the sensitivity of the sensing film, wherein the heating device is made of nichrome wire or platinum, and the heating temperature range is set at 50 ° C. to 200 ° C. in a liquid state. Measuring sensor Using the liquid state measurement sensor of any one of claims 1 to 4, The difference between the electrical conductivity (Rbias) when a predetermined voltage is applied to both ends of one electrode attached to the sensing film and the voltage application electrode formed on the side of the sensing film and the electrical conductivity (Ro) when no voltage is applied ( Liquid state detection method characterized by determining the state information of the liquid by measuring ΔR = | Rbias-Ro | The method of claim 5, The difference in electrical conductivity (ΔR = | Rbias-Ro |) is measured by selecting a distance between both ends of one electrode attached to the sensing film and the voltage applying electrode configured on the side of the sensing film in the range of 0.1 μm to 10 mm. Liquid state detection method characterized by measuring The method of claim 5, The power used to construct the electric field between the two electrodes is characterized in that the electrical conductivity (ΔR) measured in accordance with the magnitude of the voltage applied between the two electrodes using any one selected from direct current or alternating current is proportionally changed. Liquid state detection method The method of claim 7, wherein The voltage of the power supply is a liquid state detection method, characterized in that applied in the range of 1V to 220V The method of claim 5, When the sensor is immersed in the liquid, the change in the electrical conductivity (ΔR) measured by the applied electric field is generated, and the change in the electrical conductivity (ΔR) measured in the air in which the sensor is not in contact with the liquid is utilized. Liquid state sensing method characterized in that to implement a level switch function for measuring the critical flow rate of liquid

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