KR102355439B1 - Evaluation and calibration method for dew sensor - Google Patents

Abstract

The present invention provides a first step of measuring data in a low humidity environment with a relative humidity of 80% or less, a second step of fitting a characteristic curve, a third step of quantitatively evaluating a dew point sensor through the fitted characteristic curve, and the dew point A method for evaluating and calibrating a dew point sensor, comprising a fourth step of determining whether the sensor is calibrated and the degree, wherein the data is an electrical conductivity value with respect to relative humidity, and the characteristic curve indicates electrical conductivity with respect to relative humidity .

Description

EVALUATION AND CALIBRATION METHOD FOR DEW SENSOR

The present invention relates to a method for evaluating and calibrating a dew point sensor, and more particularly, to a method for evaluating and calibrating a dew point sensor using fitting a characteristic curve.

A typical humidity sensor is a sensor that displays an output proportional to the relative humidity in air. Relative humidity is the ratio of the amount of water vapor actually contained in a certain volume of air to the amount of saturated water vapor, which means the maximum amount of water vapor that can be contained, and the amount of saturated water vapor depends on the temperature.

On the other hand, a dew point sensor is a sensor that detects that water vapor in the air is condensed into water droplets. The dew point sensor can detect that water droplets actually start to form on the surface of an object regardless of the absolute amount of water vapor in the air or the relative humidity. Since there are many variables that affect the conditions for water droplets to form, it is sometimes useful to know only the information that water droplets have started to form.

One technical object of the present invention is to increase the accuracy of the dew point sensor through the evaluation and calibration method of the dew point sensor.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those of ordinary skill in the art from the following description.

In order to solve the above technical problems, the evaluation and calibration method of a dew point sensor according to an embodiment of the present invention includes a first step of measuring data in a low-humidity environment with a relative humidity of 80% or less, a second step of fitting a characteristic curve, and fitting A third step of quantitatively evaluating the dew point sensor through the characteristic curve, and a fourth step of determining whether or not the dew point sensor is calibrated and the degree, wherein the data is an electrical conductivity value for relative humidity, the characteristic The curve may represent electrical conductivity versus relative humidity.

The first step may measure two or three pieces of the data.

The method may further include transforming the x-axis and the y-axis of the characteristic curve before the second step.

Transforming the x-axis and y-axis of the characteristic curve may be performed by the following [Equation].

[Equation]

The dew point sensor may include polymer conductive particles.

In the third step, the concentration or dispersion characteristics of the polymer conductive particles may be quantitatively evaluated.

In the dew point sensor, electrical resistance may increase and electrical conductivity may decrease as relative humidity increases.

The dew point sensor may exhibit different electrical conductivity according to frequency at the same relative humidity when AC is applied.

As the frequency of the dew point sensor increases, electrical conductivity may increase.

The evaluation and calibration method of a dew point sensor according to an embodiment of the present invention includes a first step of measuring data in a low humidity environment with a relative humidity of 80% or less, a second step of fitting a characteristic curve, and a dew point sensor through the fitted characteristic curve A third step of quantitatively evaluating the , and a fourth step of determining whether the dew point sensor is calibrated and the degree of calibration, wherein the data is an electrical conductivity value for relative humidity, and the second step includes the following [Equation] It can be performed according to a function of

[Equation]

The first step may measure two or three pieces of the data.

The first step is to measure the two data, to extract the average value of the dx value and the average value of the x ₀ value of the [Equation] from the dew point sensor, and from the characteristic curve of the [Equation] determining the y ₁ value and the y _{2 value.}

The first step is to measure the three data, extract the average value of the dx values of the [Equation] from the dew point sensor, and the y ₁ value, y _{2 of the [Equation] from the characteristic curve} and determining the value of _{x 0.}

Quantitative evaluation of the dew point sensor and determination of whether or not to calibrate the dew point sensor may be performed through at least one _{of y 1} , y ₂ , x ₀ , and dx values of [Equation].

The method may further include transforming the x-axis and the y-axis of the characteristic curve before the second step.

The dew point sensor may include conductive polymer particles, and the conductive polymer particles may be composites of a hygroscopic swelling agent and an electrically conductive material.

In the third step, the concentration or dispersion characteristics of the polymer conductive particles may be quantitatively evaluated.

In the dew point sensor, electrical resistance may increase and electrical conductivity may decrease as relative humidity increases.

The dew point sensor may exhibit different electrical conductivity according to frequency at the same relative humidity when AC is applied.

As the frequency of the dew point sensor increases, electrical conductivity may increase.

The evaluation and calibration method of the dew point sensor according to the embodiment of the present invention may predict the characteristics of the dew point sensor in the entire humidity range through data measurement in a low humidity environment, and quantitatively evaluate the dew point sensor. In addition, it is possible to determine whether or not to calibrate the dew point sensor and the degree of calibration according to the evaluation of the dew point sensor, and to improve the accuracy of the dew point sensor through the calibration.

1 is a flowchart illustrating a method for evaluating and calibrating a dew point sensor according to an embodiment of the present invention.
2 and 3 are graphs illustrating characteristics of a dew point sensor that is a target of a method for evaluating and calibrating a dew point sensor according to an embodiment of the present invention.
4 and 5 are graphs for explaining a method of fitting a characteristic curve according to an evaluation and calibration method of a dew point sensor according to an embodiment of the present invention.

Hereinafter, a method for evaluating and calibrating a dew point sensor according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a flowchart illustrating a method for evaluating and calibrating a dew point sensor according to an embodiment of the present invention.

1 , the evaluation and calibration method of the dew point sensor according to the present invention includes a first step (S10) of measuring data in a low humidity environment, a second step (S20) of fitting a characteristic curve over the entire humidity range, and the fitted It may include a third step (S30) of quantitatively evaluating the characteristics of the dew point sensor through the characteristic curve, and a fourth step (S40) of determining whether or not the dew point sensor is calibrated or not.

The dew point sensor subject to the evaluation and calibration method according to the present invention may comprise a moisture sensitive material. The moisture-sensitive material may have a different degree of swelling depending on the humidity. For example, a moisture sensitive material may swell more at higher relative humidity.

The moisture-sensitive material may include polymeric conductive particles. The polymeric conductive particles may be, for example, composites of a hygroscopic swelling agent and an electrically conductive material. The hygroscopic swelling agent may be, for example, polyvinyl alcohol. The electrically conductive material may be, for example, a non-ionic conductive material such as carbon black. The moisture-sensitive material may further include substances that control the degree of swelling of the hygroscopic swelling agent.

When the degree of swelling of the moisture-sensitive material is changed, the concentration of the conductive polymer particles may be changed, and the distance between the conductive polymer particles may be changed according to the concentration of the conductive polymer particles. The distance between the polymer conductive particles may affect the electrical conductivity of the moisture-sensitive material. For example, when the concentration of the polymer conductive particles decreases due to high relative humidity and the distance between the conductive polymer particles increases, the electrical conductivity of the moisture-sensitive material may decrease. The relationship between the concentration of polymer conductive particles and the electrical conductivity can be explained by percolation theory.

In the first step S10 , the low humidity environment may be defined as an environment having a relative humidity (RH) of about 80% or less. More preferably, the low humidity environment may be defined as an environment having a relative humidity (RH) of about 70% or less, but in the present specification, the low humidity environment is an environment having a relative humidity (RH) of 80% or less, and the high humidity environment is Described as an environment having a relative humidity (RH) greater than 80%.

The data measured in the first step S10 may be an electrical conductivity value with respect to relative humidity (RH). The number of data measured in the first step S10 may be two or three. That is, the data measured in the first step S10 may be electrical conductivity values for two or three different relative humidity (RH). The number of variables that can be determined from the characteristic curve fitted in the second step S20 may vary according to the number of data. For example, when two pieces of data are measured in the first step S10, two variables may be determined from the fitted characteristic curve. Variables that can be determined from the fitted characteristic curve will be described later with reference to FIG. 5 .

The second step ( S20 ) may be to fit a characteristic curve of the entire humidity range through the data of the low humidity environment measured in the first step ( S10 ). Fitting of the characteristic curve may use a Boltzman-Sigmoid curve.

The Boltzmann-Sigmoid curve generally describes the characteristics of the conductor-insulator phase transition, and the ratio of conductor-insulator can be used as a variable of the phase transition. In the evaluation and calibration method of the dew point sensor according to the present invention, a Boltzmann-Sigmoid curve using relative humidity (RH) as a variable may be used.

The characteristic curve may be, for example, a curve indicating _{electrical conductivity (σ AC ) with respect to relative humidity (RH).} The x-axis and y-axis of the characteristic curve _{may be obtained by transforming relative humidity (RH) and electrical conductivity (σ AC} ) into first and second functions, respectively. The first function and the second function are as follows [Equation 1]. Relative humidity (RH) is expressed as a percentage (%), and _{the unit of electrical conductivity (σ AC} ) is S/m (Siemens per meter). In the following [Equation 1], the denominator and the numerator in the log function may be interchanged.

The third step (S30) may be to quantitatively evaluate the characteristics of the dew point sensor through the characteristic curve fitted in the second step (S20). The quantitatively evaluated properties of the dew point sensor may be, for example, a concentration of polymer conductive particles included in the dew point sensor and a dispersion property of the polymer conductive particles.

The fourth step ( S40 ) may be to determine whether or not the dew point sensor is calibrated and the degree of calibration through the characteristics of the dew point sensor evaluated in the third step ( S30 ). Calibration can increase the accuracy of the dew point sensor.

Water vapor starts to condense into water droplets in an environment with a relative humidity (RH) of about 90% or more. In such an environment, the characteristics of the dew point sensor change rapidly, so it may be difficult to accurately measure and calibrate the characteristics with a conventional method. In the evaluation and calibration method of the dew point sensor according to the present invention, the characteristics of the dew point sensor in a high-humidity environment can be measured more accurately, and accordingly, whether and the degree of calibration can be determined.

2 and 3 are graphs illustrating characteristics of a dew point sensor that is a target of a method for evaluating and calibrating a dew point sensor according to an embodiment of the present invention.

2 is a graph of electrical resistance versus relative humidity (RH), and FIG. 3 is a graph of _{electrical conductivity (σ AC ) versus relative humidity (RH).} Relative humidity (RH) is expressed as a percentage (%), the unit of electrical resistance is Ω (ohm), and the unit of electrical conductivity (σ _AC ) is S/m (Siemens per meter). The electrical resistance of FIG. 2 is a direct current (DC) resistance, and the electrical conductivity (σ _AC ) of FIG. 3 is an alternating current (AC) electrical conductivity.

2 and 3 , in the dew point sensor, as the relative humidity (RH) increases, the electrical resistance may increase and the electrical conductivity (σ _AC ) may decrease.

When the relative humidity (RH) increases to a certain degree or more, water droplets begin to condense, and the hygroscopic swelling agent of the dew point sensor may absorb the water droplets and swell. The swollen hygroscopic swelling agent may reduce the contact between the electrically conductive materials, thereby increasing the electrical resistance of the dew point sensor. Since electrical conductivity (σ _AC ) is inversely proportional to electrical resistance, as electrical resistance increases, electrical conductivity (σ _AC ) may decrease.

Referring to FIG. 3 , the dew point sensor may exhibit _{different electrical conductivity (σ AC} ) according to frequency at the same relative humidity (RH) when AC is applied. As the frequency increases, the electrical conductivity (σ _AC ) may increase. For example, based on the measured value when the frequency is 20 Hz, as the relative humidity (RH) increases or the frequency increases, the difference from the reference electrical conductivity (electric conductivity when the frequency is 20 Hz) may increase. This may be due to the fact that the capacitor structure is formed as the distance d between two conductors (eg, polymer conductive particles or aggregation thereof) inside the moisture-sensitive material increases in a high-humidity environment. In the capacitor structure, the higher the relative humidity (RH), the lower the capacitance (C∝A/d), and accordingly the AC electrical resistance (X _c =1/jωC) increases, and the AC electrical conductivity (σ _AC ) can decrease. In addition, when the distance (d) between conductors is constant and the capacitance (C) is constant, an increase in frequency (ω) leads to a decrease in AC electrical resistance (X _c =1/jωC) and an increase in _{AC electrical conductivity (σ AC ).} can lead

4 and 5 are graphs for explaining a method of fitting a characteristic curve according to an evaluation and calibration method of a dew point sensor according to an embodiment of the present invention.

4 shows that the characteristic curve is fitted without changing the x-axis and the y-axis of the characteristic curve.

_{The first line 410 is a line connecting the measured values of the electrical conductivity (σ AC} ) with respect to the relative humidity (RH), and the second line 420 is a curve fitting the characteristic curve using the Boltzmann-Sigmoid curve. is the line Fitting of the characteristic curve using the Boltzmann-Sigmoid curve may be performed according to the function of [Equation 2] below. Specifically, to Equation (2) of the function it is symmetrical about the x = x _0, and the slope at _{x = x 0 dx, x →} ∞ y has a value of ₂ in the extreme, x → -∞ in extreme y may have a value of _{1 .}

The first line 410 of FIG. 4 shows a tendency to be saturated in a high-humidity environment, but the second line 420, unlike this, shows a tendency to continuously decrease. This means that the Boltzmann-Sigmoid curve is _{symmetrical with respect to x=x 0 , whereas the graph of the electrical conductivity (σ AC} ) versus the relative humidity (RH) of the dew point sensor is about 90% to 100% of the section and the rest section is symmetrical. It is due to the fact that it is not hostile. This is because the data in a high-humidity environment is not precise. _{Specifically, y 1} , y ₂ , x ₀ , and dx values calculated as a result of the fitting are shown in [Table 1] below. In this case _{, the negative y 2} value is not a physical result, which is a result of the y variable electrical conductivity (σ _AC ) being considered symmetric on the Boltzmann-Sigmoid curve.

R ² =0.99823 value Standard Error y ₁ 5.84888 0.12774 y ₂ -0.2432 0.08337 x ₀ 73.42712 0.43354 dx 6.54248 0.40442

5 shows that the characteristic curve is fitted after the x-axis and the y-axis of the characteristic curve are transformed according to Equation 1 above. Linearity between variables can be improved through axial deformation.

_{The first line 510 is a line connecting the measured values of the electrical conductivity (σ AC} ) with respect to the relative humidity (RH), and the second line 520 is a curve fitting the characteristic curve using the Boltzmann-Sigmoid curve. is the line

The first line 510 and the second line 520 of FIG. 5 show substantially the same tendency. _{Specifically, y 1} , y ₂ , x ₀ , and dx values calculated as a result of the fitting are shown in [Table 2] below. At this time, although the y ₂ value is a negative number, unlike the case of [Table 1], the y ₂ value is a value obtained by taking a log, and thus can be interpreted as having very small electrical conductivity.

R ² =0.99474 value Standard Error y ₁ 0.85685 0.08647 y ₂ -2.58235 0.23697 x ₀ 0.96699 0.03769 dx 0.26241 0.03203

The dx value may represent a criticality of the dew point sensor. The dew point sensors may each have the same dx value if the material and structure are the same.

A _{value of x 0} may represent an inflection point at which a phase transition occurs. The dew point sensors may each have substantially the same x ₀ value.

Referring back to FIG. 1 , when two pieces of data are measured in the first step S10 , the y ₁ value and the y ₂ value may be determined from the characteristic curve fitted in the second step S20 . Also, when three pieces of data are measured in the first step S10 , the y ₁ value, y ₂ value, and x ₀ value may be determined from the characteristic curve fitted in the second step S20 .

Specifically, prepared in the same process, and the two pieces of data measured in the extraction of the average value of the average value and x ₀ The value of each of dx values from the dew point sensor including a same material, and extracts the average value and the step 1 (S10) It is possible to determine _{the y 1} value and the y _{2 value.}

The dew point sensors may be classified based on at least one _{of y 1} , y ₂ , x _{0 , and dx values.} Quantitative evaluation of the dew point sensor, and determination of whether or not to calibrate the dew point sensor may be performed through at least one of y ₁ , y ₂ , x _{0 , and dx values.}

The evaluation and calibration method of a dew point sensor according to an embodiment of the present invention can fit a characteristic curve of a high humidity environment through data of a low humidity environment, and evaluate the quantitative characteristics of the dew point sensor through the fitted characteristic curve, so the accuracy of the dew point sensor can be used to increase

In the above, embodiments of the present invention have been described with reference to the accompanying drawings, but those of ordinary skill in the art to which the present invention pertains can practice the present invention in other specific forms without changing the technical spirit or essential features. You will understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (20)

A first step of measuring data in a low humidity environment in which the relative humidity is 80% or less;
a second step of fitting a characteristic curve;
a third step of quantitatively evaluating the dew point sensor through the fitted characteristic curve; and
A fourth step of determining whether the dew point sensor is calibrated and the degree of calibration;
The data are electrical conductivity values for relative humidity,
The characteristic curve is an evaluation and calibration method of a dew point sensor indicating electrical conductivity with respect to relative humidity.
The method of claim 1,
The first step is an evaluation and calibration method of a dew point sensor that measures two or three of the data.
The method of claim 1,
The method of evaluating and calibrating a dew point sensor further comprising transforming the x-axis and the y-axis of the characteristic curve before the second step.
4. The method of claim 3,
Transforming the x-axis and y-axis of the characteristic curve is an evaluation and calibration method of a dew point sensor performed by the following [Equation].
[Equation]

The method of claim 1,
The dew point sensor is a method for evaluating and calibrating a dew point sensor including polymer conductive particles.
6. The method of claim 5,
The third step is an evaluation and calibration method of a dew point sensor for quantitatively evaluating the concentration or dispersion characteristics of the polymer conductive particles.
The method of claim 1,
The dew point sensor is an evaluation and calibration method of the dew point sensor, the electrical resistance increases as the relative humidity increases, and the electrical conductivity decreases.
The method of claim 1,
The dew point sensor evaluation and calibration method of the dew point sensor showing different electrical conductivity depending on the frequency at the same relative humidity when AC is applied.
9. The method of claim 8,
The dew point sensor is an evaluation and calibration method of the dew point sensor in which the electrical conductivity increases as the frequency increases.
A first step of measuring data in a low humidity environment in which the relative humidity is 80% or less;
a second step of fitting a characteristic curve;
a third step of quantitatively evaluating the dew point sensor through the fitted characteristic curve; and
A fourth step of determining whether the dew point sensor is calibrated and the degree of calibration;
The data are electrical conductivity values for relative humidity,
The second step is an evaluation and calibration method of a dew point sensor performed according to a function of the following [Equation].
[Equation]

11. The method of claim 10,
The first step is an evaluation and calibration method of a dew point sensor that measures two or three of the data.
12. The method of claim 11,
The first step is:
measuring the two data;
extracting an average value of _{dx values and an average value of x 0} values of the [Equation] from the dew point sensor; and
Evaluation and calibration method of a dew point sensor comprising determining _{the y 1} value and the y ₂ value of the [Equation] from the characteristic curve.
12. The method of claim 11,
The first step is:
measuring the three data;
extracting an average value of the dx values of the [Equation] from the dew point sensor; and
A method for evaluating and calibrating a dew point sensor, comprising determining _{the y 1} value, y ₂ value, and x ₀ value of the [Equation] from the characteristic curve.
11. The method of claim 10,
_{y 1} , y ₂ , x ₀ , and dx of the [Equation] A method for evaluating and calibrating a dew point sensor in which quantitative evaluation and calibration of the dew point sensor and determination of the degree of calibration are performed through at least one of the values.
11. The method of claim 10,
The method of evaluating and calibrating a dew point sensor further comprising transforming the x-axis and the y-axis of the characteristic curve before the second step.
11. The method of claim 10,
The dew point sensor comprises polymer conductive particles,
The method for evaluating and calibrating a dew point sensor, wherein the polymer conductive particles are composites of a hygroscopic swelling agent and an electrically conductive material.
17. The method of claim 16,
The third step is an evaluation and calibration method of a dew point sensor for quantitatively evaluating the concentration or dispersion characteristics of the polymer conductive particles.
11. The method of claim 10,
The dew point sensor is an evaluation and calibration method of the dew point sensor, the electrical resistance increases as the relative humidity increases, and the electrical conductivity decreases.
11. The method of claim 10,
The dew point sensor evaluation and calibration method of the dew point sensor showing different electrical conductivity depending on the frequency at the same relative humidity when AC is applied.
20. The method of claim 19,
The dew point sensor is an evaluation and calibration method of the dew point sensor in which the electrical conductivity increases as the frequency increases.

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