Pollutant quantity calculation device and pollutant quantity calculation method

Abstract

To provide a polluted material amount measurement device and a method for measuring the amount of a polluted material which can precisely measure the amount of attaching polluted material.SOLUTION: A housing has an opening in the upper surface. A first crystal oscillator has a first crystal plate and a first electrode pair. The first electrode pair is formed of a first metal holding the first crystal plate. The first crystal oscillator is provided so that one electrode of the first electrode pair faces the opening in the housing. A second crystal oscillator has a second crystal plate and a second electrode pair. The second electrode pair is formed of a second metal holding the second crystal plate. The second metal has a lower ionization tendency than the first metal. The second crystal oscillator is provided so that one electrode of the second electrode pair faces the opening in the housing. A first frequency measurement circuit outputs a resonance frequency of the first crystal oscillator. A second frequency measurement circuit outputs a resonance frequency of the second crystal oscillator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a pollutant amount calculation device and a pollutant amount calculation method. [Background technology]

[0002] Electric power facilities are important facilities that support social infrastructure, and are required to operate stably for a long period of time. To ensure stable operation, it is necessary to understand the deterioration state of the power facilities and to carry out maintenance and renewal in a planned manner. The insulating properties of insulating materials used for conductor supports or barriers in power facilities deteriorate over time due to the deterioration of the materials themselves and the adhesion of dust or moisture floating in the installation environment. Deterioration of insulating properties can cause discharge or tracking, which can lead to facility shutdowns, so the condition of insulating materials can serve as a barometer for diagnosing the deterioration of power facilities.

[0003] The influence of the installation environment on the deterioration of insulating materials is not limited to the adhesion of dust and moisture. In environments where environmental factors that chemically react with the components of insulating materials are present, insulating materials may deteriorate at a rate that exceeds normal aging. For example, calcium carbonate is often used as an inorganic filler in insulating materials. When calcium carbonate reacts with chlorine gases or nitrogen oxide gases, calcium chloride or calcium nitrate is formed on the surface of the insulating material. These substances absorb moisture from the air and deliquesce even at low relative humidity levels of 40% or less. Therefore, even under low humidity conditions, condensation can form on the surface of insulating materials, causing leakage current to flow across the surface of the insulating material. If this becomes severe, the insulation can be destroyed, and in the worst case, it can lead to equipment shutdowns.

[0004] It is possible to directly measure the insulation resistance of insulating materials used in power equipment in the field. However, the measured value is greatly affected by the atmosphere of the measurement location, specifically the humidity. For example, in a dry environment, the insulation resistance value is often higher than the actual value, and deterioration of the insulating material may go unnoticed. Furthermore, most power equipment shutdowns due to poor insulation occur during the rainy season, when temperatures are high and humidity are high. Therefore, directly measuring resistance values is not suitable for practical operation.

[0005] Therefore, a method has been proposed for estimating the insulation resistance of insulating materials using numerical calculations such as multivariate analysis. This method involves measuring parameters that are correlated with insulation resistance and are not affected by the ambient atmosphere at the measurement location, and then calculating the insulation resistance value based on the values of those parameters. This method involves obtaining data that correlates with insulation resistance for insulating materials used in the field and for insulating materials that have been subjected to forced degradation, and then using multivariate analysis to develop an estimation formula for insulation resistance, which serves as a diagnostic index. In insulation diagnosis, the parameters for which the estimation formula has been developed are measured, and the insulation resistance at any temperature and humidity is estimated from the insulation resistance estimation formula.

[0006] Data correlated with insulation resistance can be broadly classified as material characteristics and atmospheric factors surrounding the installation site. Traditionally, measuring these parameters required inspectors to physically measure the equipment and conduct sampling from the equipment. This made continuous monitoring of material characteristics and environmental factors impossible, resulting in discrete assessments. Recent advances in measurement technology have made it possible to continuously measure material characteristics and atmospheric environmental factors. For example, techniques for estimating material properties from the spectral reflectance of insulating materials and techniques for measuring ionic pollutants in the atmospheric environment have made continuous monitoring of insulation performance possible. Therefore, there is a need for a technology that can accurately measure the amount of pollutants, such as dust and moisture, that degrade insulating materials at a rate faster than normal aging. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5951299 [Patent Document 2] Patent No. 5836904 [Patent Document 3] Patent No. 5872643 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a pollutant amount calculation device and a pollutant amount calculation method that can accurately measure the amount of pollutants attached. [Means for solving the problem]

[0009] The fouling substance detection sensor of the embodiment has a housing, a first quartz crystal oscillator, a second quartz crystal oscillator, a first frequency measurement circuit, and a second frequency measurement circuit. The housing has an opening on its top surface. The first quartz crystal oscillator has a first quartz crystal plate and a first electrode pair. The first electrode pair is made of a first metal that sandwiches the first quartz crystal plate. The first quartz crystal oscillator is provided inside the housing with one of the first electrode pair facing the opening in the housing. The second quartz crystal oscillator has a second quartz crystal plate and a second electrode pair. The second electrode pair is made of a second metal that sandwiches the second quartz crystal plate. The second metal has a lower ionization tendency than the first metal. The second quartz crystal oscillator is provided inside the housing with one of the second electrode pair facing the opening in the housing. The first frequency measurement circuit outputs the resonant frequency of the first quartz crystal oscillator. The second frequency measurement circuit outputs the resonant frequency of the second quartz crystal oscillator. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the configuration of a contaminant amount measuring device according to a first embodiment. [Figure 2] 1 is an exploded perspective view showing the structure of a fouling substance detection sensor according to a first embodiment. [Figure 3] 2 is a cross-sectional view of a housing of the soiling substance detection sensor according to the first embodiment. FIG. [Figure 4] 3 is a cross-sectional view showing a state immediately after contaminants and non-contaminants have adhered to the first and second quartz crystal vibrators of the contaminant amount measuring device according to the first embodiment. FIG. [Figure 5] 3 is a cross-sectional view showing a state after time has passed since contaminants and non-contaminants adhered to the first and second quartz crystal vibrators of the contaminant amount measuring device according to the first embodiment. FIG. [Figure 6] 1 is a graph showing the relationship between the amount of salt adhering to a copper electrode and the rate of increase of corrosion products on the copper electrode. [Figure 7] FIG. 10 is a graph showing the relationship between the amount of salt adhering to a copper electrode and the fluctuation in the resonant frequency of the copper electrode per unit time in a salt spray test. [Figure 8] FIG. 10 is a graph showing the relationship between the amount of salt at each relative humidity of the environment and the fluctuation in the resonant frequency of the copper electrode per unit time in a salt spray test. [Figure 9] 10 is an example of a gradient derivative function showing the relationship between relative humidity and the gradient of a salinity calibration curve according to the first embodiment. [Figure 10] 1 is a schematic block diagram showing the configuration of a pollutant amount calculation device according to a first embodiment. [Figure 11] FIG. 4 is a graph showing the change over time in the frequency difference of the second quartz crystal unit relative to the first quartz crystal unit in the first embodiment. [Figure 12] 4 is a flowchart showing a method for monitoring the contamination state of an object using the contamination substance amount measuring device according to the first embodiment. [Figure 13] FIG. 10 is a diagram showing the configuration of a fouling substance detection sensor according to a second embodiment. [Figure 14] FIG. 10 is a schematic block diagram showing the configuration of a pollutant amount calculation device according to a third embodiment. [Figure 15] 10 is a flowchart showing a method for monitoring the contamination state of an object using a contamination substance amount measuring device according to a third embodiment. [Figure 16] FIG. 1 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a pollutant detection sensor, a pollutant amount calculation device, and a pollutant amount calculation method according to embodiments will be described with reference to the drawings.

[0012] (First embodiment) FIG. 1 is a schematic diagram showing the configuration of a contaminant amount measuring device 10 according to the first embodiment. The pollutant quantity measuring device 10 has a pollutant detection sensor 20 and a pollutant quantity calculation device 30. In the pollutant quantity measuring device 10 of the first embodiment, the pollutant detection sensor 20 and the pollutant quantity calculation device 30 are connected by wire. The pollutant detection sensor 20 and the pollutant quantity calculation device 30 may be connected wirelessly or via a network such as the Internet. The pollutant detection sensor 20 is installed near an object O whose pollution state is to be estimated. The pollutant quantity calculation device 30 calculates the amount of salt adhering to the pollutant detection sensor 20 and estimates the pollution state of the object O.

[0013] 2 is an exploded perspective view showing the structure of the pollutant detection sensor 20 according to the first embodiment. The pollutant detection sensor 20 includes a first quartz crystal oscillator 21, a second quartz crystal oscillator 22, a temperature and humidity sensor 23, and a housing 24. The first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 are adjacent to each other and are placed in the same environment.

[0014] The first quartz crystal unit 21 includes a first gold electrode 211, a second gold electrode 212, a quartz crystal plate 213, a support plate 214, an oscillation circuit 215, and a frequency measurement circuit 216. The first gold electrode 211 and the second gold electrode 212 are electrodes made of gold. The quartz crystal plate 213 is sandwiched between the first gold electrode 211 and the second gold electrode 212. Terminals of the first gold electrode 211 and the second gold electrode 212 are inserted into and supported by the support plate 214. The support plate 214 is fixed to the housing 24 so that the first gold electrode 211 faces upward. The oscillation circuit 215 applies a voltage between the first gold electrode 211 and the second gold electrode 212. When a voltage is applied between the first gold electrode 211 and the second gold electrode 212, the quartz crystal plate 213 vibrates and outputs an electrical signal. The frequency measurement circuit 216 measures the frequency of the electrical signal output by the first crystal vibrating element 21.

[0015] The second quartz crystal unit 22 includes a first copper electrode 221, a second copper electrode 222, a quartz crystal plate 223, a support plate 224, an oscillation circuit 225, and a frequency measurement circuit 226. The first copper electrode 221 and the second copper electrode 222 are electrodes made of copper. The quartz crystal plate 223 is sandwiched between the first copper electrode 221 and the second copper electrode 222. Terminals of the first copper electrode 221 and the second copper electrode 222 are inserted into and supported by the support plate 224. The support plate 224 is fixed to the housing 24 so that the first copper electrode 221 faces upward. The oscillation circuit 225 applies a voltage between the first copper electrode 221 and the second copper electrode 222. When a voltage is applied between the first copper electrode 221 and the second copper electrode 222, the quartz crystal plate 223 vibrates and outputs an electrical signal. The frequency measurement circuit 226 measures the frequency of the electrical signal output by the second quartz crystal vibrator 22 .

[0016] The temperature and humidity sensor 23 is provided near the second quartz crystal vibrating element 22 and measures the temperature and relative humidity around the second quartz crystal vibrating element 22 .

[0017] FIG. 3 is a cross-sectional view of the housing 24 of the soiling substance detection sensor 20 according to the first embodiment. The housing 24 forms the outer shell of the soiling substance detection sensor 20. The housing 24 includes a main body 241 and a lid 242. The main body 241 is a box having an open top and a bottom. The lid 242 is provided to cover the opening of the main body 241. A through-hole 242a is provided in each of the portions of the lid 242 facing the first gold electrode 211 and the first copper electrode 221. This allows particles floating near the object O to enter the housing 24 through the through-hole 242a. Because the first gold electrode 211 and the first copper electrode 221 are provided directly below the through-hole 242a, the particles are likely to adhere to the first gold electrode 211 or the first copper electrode 221. The through-hole 242a is tapered, with a wide upper surface and a narrow lower surface. The bottom surface of through-hole 242a may be designed to be the same size as the disk portion of the opposing electrode. Alternatively, through-hole 242a may be designed so that the edge of the electrode is positioned on an extension of the side wall. By configuring through-hole 242a in a tapered shape, it is possible to guide particles floating in the air into housing 24 without trapping them at the upper edge of through-hole 242a.

[0018] Tubular protrusions 241a are formed on the bottom surface of main body 241 of housing 24 at portions facing the outer edge of second gold electrode 212, portions facing the outer edge of quartz crystal plate 213, portions facing the outer edge of second copper electrode 222, and portions facing the outer edge of quartz crystal plate 223. Protrusions 241a have a height that prevents them from coming into contact with first quartz crystal vibrator 21 and second quartz crystal vibrator 22 even when first quartz crystal vibrator 21 and second quartz crystal vibrator 22 vibrate. Providing protrusions 241a traps fine particles that enter through through-holes 242a and do not adhere to first gold electrode 211 or first copper electrode 221, preventing the fine particles from adhering to second gold electrode 212 or second copper electrode 222. If the fine particles accumulated at the bottom of the housing 24 adhere to the second gold electrode 212 or the second copper electrode 222, the resonance frequencies of the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 may suddenly fluctuate, possibly resulting in a decrease in detection accuracy. The shape of the protrusion 241a does not have to be ring-shaped as shown in Figure 2, and may be any closed hollow tubular shape such as a square or hexagon.

[0019] The first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 are, for example, QCMs (quartz crystal microbalances). The first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 are pre-calibrated so that, in their initial state, the frequency fluctuations are equal when the mass changes of the electrodes are the same. In other words, the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 have the same resonant frequency in their initial state.

[0020] Copper has a lower ionization tendency (standard electrode potential) than gold. In other words, copper is a metal that is more susceptible to corrosion by ionic contaminants such as salt than gold. Therefore, when salt adheres to both the first gold electrode 211 of the first quartz crystal oscillator 21 and the first copper electrode 221 of the second quartz crystal oscillator 22, corrosion products are likely to be generated on the first copper electrode 221. The resonant frequency of the second quartz crystal oscillator 22 changes relative to the resonant frequency of the first quartz crystal oscillator 21 in response to a change in the mass of the first copper electrode 221 due to the amount of corrosion products generated. The adhesion of ionic contaminants to the first copper electrode 221 changes the resonant frequency of the second quartz crystal oscillator 22 relative to the resonant frequency of the first quartz crystal oscillator 21.

[0021] Here, the behavior of the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 when contaminants (salt) and non-contaminants (dust, etc.) adhere to them will be described with reference to FIGS. 4 and 5. FIG. 4 is a cross-sectional view showing the state immediately after contaminants and non-contaminants adhere to the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 of the contaminant amount measuring device 10 of the first embodiment. FIG. 4(a) shows the state immediately after contaminants A and non-contaminants B adhere to the first gold electrode 211 of the first quartz crystal oscillator 21. FIG. 4(b) shows the state immediately after contaminants A and non-contaminants B adhere to the second gold electrode 212 of the second quartz crystal oscillator 22. Contaminant A is an ionic substance. Examples of ionic substances include chlorine-based gases and nitrogen oxide gases. Non-contaminant B is, for example, dust or water. As shown in Figures 4(a) and (b), the adhesion of contaminant A and non-contaminant B changes the mass of the first gold electrode 211 and the second gold electrode 212. As a result, the resonant frequency of the first quartz crystal oscillator 21 and the resonant frequency of the second quartz crystal oscillator 22 each fluctuate. However, immediately after the adhesion of contaminant A and non-contaminant B, the second gold electrode 212 is not corroded, and no difference in mass occurs between the first gold electrode 211 and the second gold electrode 212. Therefore, the resonant frequency due to the increase in electrode mass and the amount of change in the resonant frequency are the same. Therefore, the resonant frequency of the second quartz crystal oscillator 22 does not fluctuate relative to the resonant frequency of the first quartz crystal oscillator 21.

[0022] Fig. 5 is a cross-sectional view showing a state after time has passed since contaminants and non-contaminants adhered to the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 of the contaminant amount measuring device 10 of this embodiment. Fig. 5(a) is a cross-sectional view showing a state after time has passed since contaminants A and non-contaminants B adhered to the first gold electrode 211 of the first quartz crystal oscillator 21. Fig. 5(b) is a cross-sectional view showing a state after time has passed since contaminants A and non-contaminants B adhered to the second gold electrode 212 of the second quartz crystal oscillator 22. As shown in FIG. 5(a), the first gold electrode 211 of the first quartz crystal oscillator 21 does not change over time after the attachment of contaminant A and non-contaminant B. On the other hand, as shown in FIG. 5(b), the second gold electrode 212 of the second quartz crystal oscillator 22 does not change in the portion where non-contaminant B is attached, but corrodes in the portion where contaminant A is attached, generating corrosion product C. The resonant frequency of the second quartz crystal oscillator 22 fluctuates due to a change in the mass of the second gold electrode 212 accompanying a change in the amount of generated corrosion product C. In other words, the resonant frequency of the second quartz crystal oscillator 22 fluctuates relative to the resonant frequency of the first quartz crystal oscillator 21. Therefore, the contaminant amount measuring device 10 of this embodiment can measure the amount of generated corrosion product C, i.e., the amount of attached contaminant A, based on the fluctuation in the resonant frequency of the second quartz crystal oscillator 22, without being affected by the amount of attached non-contaminant B.

[0023] Corrosion of the first copper electrode 221 is accelerated by the adhesion of salt, an ionic substance. FIG. 6 is a diagram showing the relationship between the amount of salt adhering to the copper electrode and the rate of increase of corrosion products on the copper electrode. As shown in FIG. 6, there is a strong correlation between the amount of salt adhering to the copper electrode and the rate of increase of corrosion products. The relationship shown in FIG. 6 was confirmed by a salt spray test on the copper electrode. FIG. 7 is a diagram showing the relationship between the amount of salt adhering to the copper electrode and the fluctuation in the resonant frequency of the copper electrode per unit time in a salt spray test. As shown in FIG. 7, the salt spray test confirmed that there is a correlation between the amount of salt and the frequency fluctuation per unit time. The contaminant amount calculation device 30 according to the first embodiment derives the amount of adhering salt from the resonant frequency of the second quartz crystal resonator 22 using a calibration curve function, which is a linear function that represents the relationship between the resonant frequency and the amount of salt.

[0024] The resonant frequency of the second quartz crystal unit 22 is affected by the temperature of the environment. This is because the second quartz crystal unit 22 has temperature characteristics. Therefore, the temperature characteristics of the second quartz crystal unit 22 are specified in advance, and the contamination amount calculation device 30 uses this to correct the corrosion rate of the second gold electrode 212. Note that the temperature characteristics of the second quartz crystal unit 22 may be the well-known temperature characteristics of an AT-cut quartz crystal (the relationship between temperature and frequency deviation). The temperature characteristics of a typical AT-cut quartz crystal are expressed by a cubic function with an inflection point at 25°C.

[0025] The corrosion rate of a copper electrode is affected by the relative humidity of the environment. The higher the relative humidity of the environment, the faster the corrosion of the copper electrode progresses. FIG. 8 is a diagram showing the relationship between the amount of salt at each relative humidity of the environment and the change in the resonant frequency of the copper electrode per unit time in a salt spray test. As shown in FIG. 8, the relationship between the relative humidity and the slope of the salt calibration curve is determined in advance by conducting a salt spray test or the like. FIG. 9 is an example of a gradient derivation function showing the relationship between the relative humidity and the slope of the salt calibration curve. The contaminant quantity calculation device 30 uses the gradient derivation function to identify the gradient of the calibration curve function. The gradient derivation function according to the first embodiment is approximated to an exponential function as shown in FIG. 9. In other embodiments, the gradient derivation function may be approximated to a quadratic function.

[0026] FIG. 10 is a schematic block diagram showing the configuration of a pollutant amount calculation device 30 according to the first embodiment. The pollutant substance amount calculation device 30 has a database 31, a measurement data storage unit 32, a temperature correction unit 33, a smoothing unit 34, a fluctuation amount calculation unit 35, a calibration curve determination unit 36, a salt content calculation unit 37, an object diagnosis unit 38, a sensor diagnosis unit 39, and an alarm unit 40.

[0027] The database 31 stores the temperature characteristic function of the second quartz crystal unit 22 and the gradient derivative function shown in FIG.

[0028] The measurement data storage unit 32 reads and stores the measurement data from the contamination detection sensor 20 at regular time intervals. The time interval is not particularly limited, but may be, for example, one minute. Specifically, the measurement data storage unit 32 stores the resonant frequency of the first quartz crystal oscillator 21 measured by the frequency measurement circuit 216, the resonant frequency of the second quartz crystal oscillator 22 measured by the frequency measurement circuit 226, and the temperature and relative humidity measured by the temperature and humidity sensor 23.

[0029] The temperature correction unit 33 corrects the resonant frequencies of the first and second quartz crystal units 21 and 22 recorded in the measurement data storage unit 32 based on the temperatures recorded in the measurement data storage unit 32 and the temperature characteristic function recorded in the database 31. Specifically, the temperature correction unit 33 calculates the frequency deviation by substituting the temperature into the temperature characteristic function, and corrects the resonant frequency to the resonant frequency at a reference temperature (e.g., 25°C). Hereinafter, the resonant frequency corrected by the temperature correction unit 33 will be referred to as the corrected frequency.

[0030] The smoothing unit 34 calculates the moving average value for each unit time of the corrected frequencies of the first and second crystal oscillators 21 and 22, as well as the relative humidity. For example, the smoothing unit 34 calculates the moving average value for time-series data at one-minute intervals, using a 12-hour window.

[0031] The fluctuation amount calculation unit 35 calculates the time derivative of the frequency fluctuation of the second quartz crystal unit 22 caused by corrosion of the first copper electrode 221. Specifically, the fluctuation amount calculation unit 35 calculates the frequency fluctuation using the following procedure. First, the fluctuation amount calculation unit 35 calculates the frequency difference of the second quartz crystal unit 22 relative to the first quartz crystal unit 21 by subtracting the moving average value of the corrected frequency of the first quartz crystal unit 21 from the moving average value of the corrected frequency of the second quartz crystal unit 22. The fluctuation amount calculation unit 35 calculates the frequency fluctuation by dividing the difference between the obtained frequency difference and the frequency difference related to a time a certain time ago (e.g., one hour ago) by the certain time.

[0032] The calibration curve determination unit 36 determines the gradient of the calibration curve by substituting the moving average value of the relative humidity calculated by the smoothing unit 34 into the gradient derivation function stored in the database 31 .

[0033] The salt content calculation unit 37 determines the amount of salt adhered to the second quartz crystal oscillator 22 based on the calibration curve relating to the gradient determined by the calibration curve determination unit 36 and the amount of frequency fluctuation calculated by the fluctuation amount calculation unit 35.

[0034] The object diagnosis unit 38 diagnoses the contamination state of the object O based on the amount of salt calculated by the salt amount calculation unit 37. Specifically, the object diagnosis unit 38 determines that the object O is in a clean state if the amount of salt calculated by the salt amount calculation unit 37 is less than a first threshold, determines that the object O is in a lightly contaminated state if the amount of salt is equal to or greater than the first threshold and less than a second threshold, determines that the object O is in a moderately contaminated state if the amount of salt is equal to or greater than the second threshold and less than a third threshold, determines that the object O is in a heavily contaminated state if the amount of salt is equal to or greater than the third threshold and less than a fourth threshold, and determines that the object O is in an extremely heavily contaminated state if the amount of salt is equal to or greater than the fourth threshold. In addition, the object diagnosis unit 38 calculates the rate of increase of the amount of salt over a certain period of time based on the amount of salt calculated by the salt amount calculation unit 37, and determines that a sudden change has occurred in the environment of the object O if the rate of increase exceeds a fifth threshold. That is, when the measured salt content is significantly different from the contamination trend seen from the salt content measured over time, the object diagnosis unit 38 determines that rapid contamination has occurred in a short period of time.

[0035] The sensor diagnostic unit 39 diagnoses the condition of the contamination detection sensor 20 based on the moving average value of the corrected frequency of the first quartz crystal unit 21 calculated by the smoothing unit 34 and the frequency difference of the second quartz crystal unit 22 relative to the first quartz crystal unit 21 calculated by the fluctuation amount calculation unit 35. Specifically, the sensor diagnostic unit 39 determines that a large amount of dust has accumulated on the contamination detection sensor 20 when the difference between the initial value of the resonant frequency of the first quartz crystal unit 21 and the moving average value of the corrected frequency of the first quartz crystal unit 21 exceeds a sixth threshold. The volume of dust affects the accuracy of detecting the contamination state. Furthermore, the sensor diagnostic unit 39 determines that corrosion of the first copper electrode 221 has progressed and is approaching saturation when the frequency difference of the second quartz crystal unit 22 relative to the first quartz crystal unit 21 exceeds a seventh threshold. FIG. 11 shows the time-dependent change in the frequency difference of the second quartz crystal unit 22 relative to the first quartz crystal unit 21. As shown in FIG. 11, when the corrosion of the first copper electrode 221 progresses and approaches a saturated state, the corrosion becomes more difficult to progress, and the accuracy of detecting the contamination state decreases.

[0036] The alarm unit 40 outputs the diagnosis results of the object diagnosis unit 38 and the sensor diagnosis unit 39. Specifically, if the object O is determined to be in a moderately polluted state, the alarm unit 40 outputs a message notifying that the pollution of the object O is progressing. If the object O is determined to be in a heavily polluted state or an extremely heavily polluted state, the alarm unit 40 outputs an alarm notifying that the time to replace the object O is approaching. Furthermore, if it is determined that a sudden change in the environment of the object O has occurred due to the rate of increase in the salt content, the alarm unit 40 outputs an alarm recommending that the condition of the object O be checked. Furthermore, if it is determined that dust has accumulated on the pollution substance detection sensor 20, the alarm unit 40 outputs an alarm urging the user to clean the pollution substance detection sensor 20. If it is determined that the corrosion of the first copper electrode 221 is approaching saturation, the alarm unit 40 outputs an alarm urging the user to replace the pollution substance detection sensor 20. The alarm may be output to a display, may be output as a sound, or may be communicated to another terminal.

[0037] 12 is a flowchart showing a method for monitoring the contamination state of the object O using the contamination substance amount measuring device 10 according to the first embodiment. When an operator installs the contamination substance detection sensor 20 near the object O and starts the contamination substance amount calculation device 30, the contamination substance amount calculation device 30 starts monitoring the contamination state of the object O.

[0038] First, the measurement data storage unit 32 reads the resonant frequency of the first quartz crystal oscillator 21, the resonant frequency of the second quartz crystal oscillator 22, the temperature, and the relative humidity from the contamination detection sensor 20, and stores them in association with the read time (step S1). The temperature correction unit 33 corrects the resonant frequencies of the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 recorded in the measurement data storage unit 32 based on the temperature recorded in step S1 and the temperature characteristic function recorded in the database 31, and records the corrected frequencies in association with the measurement data of step S1 in the measurement data storage unit 32 (step S2).

[0039] The smoothing unit 34 calculates the moving average values of the corrected frequencies and relative humidity of the first and second crystal units 21 and 22 stored in the measurement data storage unit 32, and stores the calculated values in association with the measurement data of step S1 in the measurement data storage unit 32 (step S3). Specifically, the smoothing unit 34 reads the corrected frequencies and relative humidity of the first and second crystal units 21 and 22 associated with a certain period of time prior to the current time from the measurement data storage unit 32, and calculates the average values. The fluctuation calculation unit 35 subtracts the moving average value of the corrected frequency of the first crystal unit 21 from the moving average value of the corrected frequency of the second crystal unit 22 calculated in step S3 to calculate the frequency difference of the second crystal unit 22 relative to the first crystal unit 21, and stores the calculated values in association with the measurement data of step S1 in the measurement data storage unit 32 (step S4). The fluctuation amount calculation unit 35 calculates the amount of frequency fluctuation by dividing the difference between the frequency difference obtained in step S4 and the frequency difference recorded in the measurement data storage unit 32 in association with a time a certain time before the current time by a certain time (step S5).

[0040] The calibration curve determination unit 36 determines the gradient of the calibration curve (step S6) by substituting the moving average value of the relative humidity calculated in step S3 into the gradient derivation function stored in the database 31. The salt content calculation unit 37 calculates the amount of salt adhered to the second quartz crystal resonator 22 based on the calibration curve corresponding to the gradient determined in step S6 and the amount of frequency fluctuation calculated in step S5 (step S7).

[0041] The object diagnosis unit 38 estimates the contamination state of the object O by comparing the amount of salt calculated in step S7 with a threshold value (step S8). The object diagnosis unit 38 determines whether the contamination state of the object O is at or above the heavy contamination state (step S9). If the contamination state of the object O is at or above the heavy contamination state (step S9: YES), the notification unit 40 outputs an alarm notifying the progression of contamination of the object O (step S10). For example, the notification unit 40 outputs an alarm such as "It is approaching the time to replace the target device."

[0042] Furthermore, the object diagnosis unit 38 determines whether the rate of increase in the amount of salt calculated in step S7 exceeds a fifth threshold value (step S11). If the rate of increase in the amount of salt exceeds the fifth threshold value (step S11: YES), the notification unit 40 outputs an alarm recommending that the condition of the object O be checked (step S12). For example, the notification unit 40 outputs an alarm such as "Sudden contamination has been detected. Please check for any abnormalities."

[0043] The sensor diagnostic unit 39 determines whether the difference between the corrected frequency of the first quartz crystal oscillator 21 associated with the oldest time recorded in the measurement data storage unit 32 and the moving average value of the corrected frequency of the first quartz crystal oscillator 21 calculated in step S3 exceeds a sixth threshold (step S13). If the difference from the moving average value of the corrected frequency exceeds the sixth threshold (step S13: YES), the alarm unit 40 outputs an alarm urging the user to clean the fouling material detection sensor 20 (step S14). For example, the alarm unit 40 outputs an alarm such as "We recommend cleaning the interior of the panel."

[0044] The sensor diagnosis unit 39 determines whether the frequency difference calculated in step S4 exceeds the seventh threshold value (step S15). If the frequency difference exceeds the seventh threshold value (step S15: YES), the notification unit 40 outputs an alarm urging the user to replace the contaminant detection sensor 20 (step S16). For example, the notification unit 40 outputs an alarm such as "The time to replace the electrode (copper) is approaching." Then, the contaminant amount calculation device 30 returns the process to step S1 and continues monitoring the object O.

[0045] As described above, the fouling substance detection sensor 20 according to the first embodiment includes two quartz crystal oscillators, and the metals constituting the electrodes have different ionization tendencies. Specifically, the fouling substance detection sensor 20 includes a first quartz crystal oscillator 21 having a gold electrode and a second quartz crystal oscillator 22 having a copper electrode. As a result, the amount of fouling substances adhering to the fouling substance detection sensor 20 appears as the difference in frequency between the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22. As a result, the amount of fouling substances adhering to the fouling substance detection sensor 20 can be measured with high accuracy by using the fouling substance detection sensor 20.

[0046] In the fouling substance detection sensor 20 according to the first embodiment, the first gold electrode 211 and the first copper electrode 221 are arranged to face the opening of the housing 24. This allows the fouling substance detection sensor 20 to reduce the possibility that adhered particles will fall off from the first gold electrode 211 and the first copper electrode 221.

[0047] Furthermore, the housing 24 of the pollutant detection sensor 20 according to the first embodiment has, on the lower surface thereof facing the second copper electrode 222, a tubular protrusion 241a having the same diameter as the outer edge of the second copper electrode 222, and a tubular protrusion 241a having a diameter larger than the outer edge of the second copper electrode 222. This allows pollutants that have entered the housing 24 to be trapped by the protrusion 241a, preventing the pollutants from adhering to the second copper electrode 222.

[0048] Furthermore, a tapered through-hole 242a that widens upward is provided on the upper surface of the housing 24 of the pollutant detection sensor 20 according to the first embodiment, and the first gold electrode 211 and the first copper electrode 221 are provided to face the through-hole 242a. This allows the pollutant detection sensor 20 to guide fine particles floating in the air to the first gold electrode 211 and the first copper electrode 221, while preventing the fine particles from entering the housing 24 without adhering to the first gold electrode 211 and the first copper electrode 221.

[0049] (Second embodiment) 11, the detection accuracy of the pollutant detection sensor 20 according to the first embodiment decreases when the corrosion of the first copper electrode 221 becomes saturated, and therefore the second quartz crystal resonator 22 needs to be replaced after a certain period of use. In contrast, the pollutant detection sensor 20 according to the second embodiment can be used for a long period of time.

[0050] FIG. 13 is a diagram illustrating the configuration of a contaminant detection sensor 20 according to a second embodiment. The contaminant detection sensor 20 according to the second embodiment includes multiple second quartz crystal oscillators 22. The number of second quartz crystal oscillators 22 according to the second embodiment is denoted as N. The housing 24 is provided with N-1 protective covers 242b, each of which exposes one of the N second quartz crystal oscillators 22 through the through-hole 242a and shields the remaining second quartz crystal oscillators 22 from the outside air. Each protective cover 242b is slidably mounted along a rail 232c on the lid 242, crossing the through-hole 242a facing the corresponding second quartz crystal oscillator 22. An actuator (not shown) is mounted on each protective cover 242b, sliding the protective cover 242b along the rail 232c.

[0051] The contaminant detection sensor 20 according to the second embodiment measures the resonant frequency of the exposed second quartz crystal oscillator 22. When the frequency difference calculated by the fluctuation amount calculation unit 35 exceeds the seventh threshold, i.e., when corrosion of the exposed second quartz crystal oscillator 22 reaches a certain level, the notification unit 40 of the contaminant amount calculation device 30 according to the second embodiment outputs a drive signal to the actuator of the protective cover 242b. This causes the protective cover 242b to slide, switching the exposed second quartz crystal oscillator 22. The measurement data storage unit 32 measures and records the resonant frequencies of the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 when switching the second quartz crystal oscillator 22. In this way, the contaminant detection sensor 20 according to the second embodiment switches the second quartz crystal oscillator 22 each time the second quartz crystal oscillator 22 deteriorates to a certain level, enabling long-term use.

[0052] (Third embodiment) The pollutant detection sensor 20 according to the first embodiment requires replacement of the second quartz crystal oscillator 22 after a certain period of use. In contrast, the pollutant quantity measuring device 10 according to the third embodiment allows for long-term use without replacing the second quartz crystal oscillator 22. The configuration of the pollutant detection sensor 20 according to the third embodiment is the same as that of the first embodiment.

[0053] 14 is a schematic block diagram showing the configuration of a pollutant amount calculation device 30 according to the third embodiment. The pollutant amount calculation device 30 according to the third embodiment further includes a calibration curve generation unit 41 in addition to the configuration of the first embodiment. The calibration curve generation unit 41 generates a second calibration curve function for determining the amount of salt from the resonant frequency of the first quartz crystal oscillator 21 based on the moving average value of the resonant frequency of the first quartz crystal oscillator 21 calculated by the smoothing unit 34 and the amount of salt calculated by the salt amount calculation unit 37.

[0054] FIG. 15 is a flowchart showing a method for monitoring the contamination state of the object O by the contamination substance amount measuring device 10 according to the third embodiment. First, the measurement data storage unit 32 reads the resonant frequency of the first quartz crystal oscillator 21, the resonant frequency of the second quartz crystal oscillator 22, the temperature, and the relative humidity from the contamination detection sensor 20, and stores them in association with the read time (step S51). The temperature correction unit 33 corrects the resonant frequencies of the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22 recorded in the measurement data storage unit 32 based on the temperature recorded in step S51 and the temperature characteristic function recorded in the database 31, and records the corrected frequencies in association with the measurement data of step S51 in the measurement data storage unit 32 (step S52).

[0055] The smoothing unit 34 calculates the moving average values of the corrected frequencies of the first and second crystal vibrators 21 and 22, as well as the relative humidity, recorded in the measurement data storage unit 32, and stores the calculated values in association with the measurement data of step S51 in the measurement data storage unit 32 (step S53). The fluctuation amount calculation unit 35 calculates the frequency difference of the second crystal vibrator 22 relative to the first crystal vibrator 21 by subtracting the moving average value of the corrected frequency of the first crystal vibrator 21 from the moving average value of the corrected frequency of the second crystal vibrator 22 calculated in step S53, and stores the calculated value in association with the measurement data of step S51 in the measurement data storage unit 32 (step S54).

[0056] The sensor diagnosis unit 39 determines whether the frequency difference calculated in step S54 exceeds a seventh threshold (step S55). If the frequency difference does not exceed the seventh threshold (step S55: NO), the fluctuation amount calculation unit 35 calculates the amount of frequency fluctuation by dividing the difference between the frequency difference obtained in step S54 and the frequency difference recorded in the measurement data storage unit 32 in association with a time a certain time before the current time by the certain time (step S56).

[0057] The calibration curve determination unit 36 determines the gradient of the calibration curve by substituting the moving average value of the relative humidity calculated in step S53 into the gradient derivation function stored in the database 31 (step S57). The salt content calculation unit 37 calculates the amount of salt adhering to the second quartz crystal resonator 22 based on the calibration curve corresponding to the gradient determined in step S57 and the amount of frequency fluctuation calculated in step S56 (step S58). The salt content calculation unit 37 records the calculated amount of salt in the measurement data storage unit 32 in association with the measurement data of step S51 (step S59).

[0058] On the other hand, if the frequency difference exceeds the seventh threshold (step S55: YES), the calibration curve generator 41 generates a second calibration curve function for determining the salt content from the resonant frequency of the first quartz crystal oscillator 21 based on the combination of the moving average value of the corrected frequency of the first quartz crystal oscillator 21 and the salt content recorded in the measurement data storage unit 32 (step S60). The calibration curve generator 41 records the second calibration curve function in the database 31.

[0059] The salt content calculation unit 37 calculates the amount of salt adhered to the second quartz crystal oscillator 22 based on the second calibration curve function generated in step S60 and the moving average value of the corrected frequency of the first quartz crystal oscillator 21 calculated in step S54 (step S61).

[0060] The object diagnosis unit 38 estimates the contamination state of the object O by comparing the amount of salt calculated in step S58 or step S61 with a threshold value (step S62). The object diagnosis unit 38 determines whether the contamination state of the object O is at or above the heavy contamination state (step S63). If the contamination state of the object O is at or above the heavy contamination state (step S63: YES), the notification unit 40 outputs an alarm recommending that the condition of the object O be checked (step S64).

[0061] Furthermore, the object diagnosis unit 38 determines whether the rate of increase in the amount of salt calculated in step S58 or step S61 exceeds a fifth threshold (step S65). If the rate of increase in the amount of salt exceeds the fifth threshold (step S65: YES), the notification unit 40 outputs an alarm recommending that the condition of the object O be checked (step S66).

[0062] The sensor diagnosis unit 39 determines whether the difference between the corrected frequency of the first quartz crystal oscillator 21 associated with the oldest time recorded in the measurement data storage unit 32 and the moving average value of the corrected frequency of the first quartz crystal oscillator 21 calculated in step S53 exceeds a sixth threshold (step S67). If the difference from the moving average value of the corrected frequency exceeds the sixth threshold (step S67: YES), the notification unit 40 outputs an alarm urging the user to clean the contaminant detection sensor 20 (step S68). The contaminant amount calculation device 30 then returns the process to step S51 and continues monitoring the object O.

[0063] In this way, when the ratio of contaminants to microparticles in the environment of the object O is approximately constant, the amount of contaminants can be estimated from the change in the resonance frequency of the first quartz crystal vibrator 21, i.e., the change in weight due to the accumulation of contaminants and non-contaminants. Therefore, according to the contaminant amount measuring device 10 of the third embodiment, the amount of contaminants can be estimated using only the first quartz crystal vibrator 21, even after the first copper electrode 221 is saturated.

[0064] According to at least one of the embodiments described above, the pollutant detection sensor 20 includes two quartz crystal oscillators, and the metals constituting the electrodes have different ionization tendencies. As a result, the amount of pollutants adhering to the pollutant detection sensor 20 appears as the difference in frequency between the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22. As a result, by using the pollutant detection sensor 20, the amount of pollutants adhering can be measured with high accuracy.

[0065] <Computer Configuration> FIG. 16 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. The computer 50 includes a processor 51 , a main memory 53 , a storage 55 , and an interface 57 . The above-described pollutant amount calculation device 30 is implemented in a computer 50 shown in Fig. 16. The operations of each of the above-described processing units are stored in the form of a program in a storage 55. A processor 51 reads the program from the storage 55, loads it into a main memory 53, and executes the above-described processing in accordance with the program. The processor 51 also allocates storage areas in the main memory 53 corresponding to each of the above-described storage units in accordance with the program. Examples of the processor 51 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0066] The program may be for realizing some of the functions to be performed by the computer 50. For example, the program may be combined with other programs already stored in storage or implemented in other devices to perform the functions. In other embodiments, the computer 50 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor 51 may be realized by the integrated circuit. Such an integrated circuit is also an example of a processor.

[0067] Examples of storage 55 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. Storage 55 may be an internal medium directly connected to the bus of computer 50, or an external medium connected to computer 50 via interface 57 or a communication line. Furthermore, when this program is distributed to computer 50 via a communication line, computer 50 that receives the program may load the program into main memory 53 and execute the above-described processing. In at least one embodiment, storage 55 is a non-transitory tangible storage medium.

[0068] The program may also be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 55.

[0069] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0070] For example, the electrodes of the first quartz crystal vibrator 21 may be made of gold, and the electrodes of the second quartz crystal vibrator 22 may be made of copper, but this is not a limitation. The electrodes of the second quartz crystal vibrator 22 may be made of a metal with a lower ionization tendency (standard electrode potential) than the electrodes of the first quartz crystal vibrator 21. In other words, the electrodes of the second quartz crystal vibrator 22 are preferably made of a metal that is more susceptible to corrosion by ionic contaminants than the electrodes of the first quartz crystal vibrator 21.

[0071] For example, the electrodes of the first quartz crystal unit 21 may be made of silver (standard electrode potential: +0.799 V) or platinum (standard electrode potential: +1.188 V), and the electrodes of the second quartz crystal unit 22 may be made of aluminum (standard electrode potential: -1.68 V). [Explanation of symbols]

[0072] 10... Contamination substance amount measuring device 20... Contamination substance detection sensor 21... First quartz crystal oscillator 211... First gold electrode 212... Second gold electrode 213... Quartz crystal plate 214... Support plate 215... Oscillator circuit 216... Frequency measurement circuit 22... Second quartz crystal oscillator 221... First copper electrode 222... Second copper electrode 223... Quartz crystal plate 224... Support plate 225... Oscillator circuit 226... Frequency measurement circuit 23... Temperature and humidity sensor 232c... Rail 24... Housing 241... Main body 241a... Protrusion 242... Lid 242a... Through hole 242b... Protective cover 30... Contamination substance amount calculation device 31... Database 32... Measurement data storage unit 33... Temperature correction unit 34... Smoothing unit 35... Fluctuation amount calculation unit 36... Calibration curve determination unit 37... Salt content calculation unit 38... Object diagnosis unit 39... Sensor diagnosis unit 40... Notification unit 41... Calibration curve generation unit 50... Computer 51... Processor 53... Main memory 55... Storage 57... Interface A... Contaminating substance B... Non-contaminating substance C... Corrosion product O... Object

Claims

1. a housing having an opening on its top surface; a first quartz crystal unit including a first electrode pair made of a first metal sandwiching the first quartz crystal plate, the first electrode pair being disposed inside the housing such that one of the first electrodes faces the opening; a second quartz crystal unit including a second electrode pair sandwiching the second quartz crystal plate and made of a second metal having a lower ionization tendency than the first metal, the second electrode pair being disposed inside the housing such that one of the second electrode pair faces the opening; a first frequency measurement circuit that outputs a resonance frequency of the first crystal resonator; a second frequency measurement circuit that outputs the resonance frequency of the second crystal resonator; A pollutant amount calculation device that calculates the amount of pollutants using a pollutant detection sensor comprising: a contamination amount calculation unit that calculates the amount of contamination based on a calibration curve function that defines the relationship between the frequency fluctuation difference between the first crystal oscillator and the second crystal oscillator and the amount of contamination; A pollutant quantity calculation device comprising:

2. a measurement data storage unit that stores measurement data of the relative humidity near the second quartz crystal vibrator; a calibration curve determination unit that calculates the gradient of the calibration curve function based on a derivative function that defines the relationship between the relative humidity and the gradient of the calibration curve function; The pollutant amount calculation device according to claim 1 , comprising:

3. The device is provided with a notification unit that issues an alarm when the amount of the polluting substance is equal to or greater than a threshold value. The pollutant quantity calculation device according to claim 1 or 2.

4. The system further includes a notification unit that issues an alarm when the change in the amount of contaminants is equal to or greater than a threshold value. The pollutant quantity calculation device according to claim 1 or 2.

5. and a notification unit that issues an alarm when the resonance frequency of the first crystal oscillator is equal to or greater than a threshold value. The pollutant quantity calculation device according to claim 1 or 2.

6. and a notification unit that issues an alarm when the difference in frequency fluctuation between the first crystal unit and the second crystal unit is equal to or greater than a threshold value. The pollutant quantity calculation device according to claim 1 or 2.

7. When the frequency fluctuation difference between the first crystal oscillator and the second crystal oscillator is equal to or greater than a threshold value, the contamination amount calculation unit calculates the contamination amount from the resonance frequency of the first crystal oscillator based on the relationship between the resonance frequency of the first crystal oscillator and the contamination amount calculated from the frequency fluctuation difference between the first crystal oscillator and the second crystal oscillator. The pollutant quantity calculation device according to any one of claims 1 to 6.

8. The first metal is gold and the second metal is copper. The pollutant quantity calculation device according to any one of claims 1 to 7.

9. a housing having an opening on its top surface; a first quartz crystal unit including a first electrode pair made of a first metal sandwiching the first quartz crystal plate, the first electrode pair being disposed inside the housing such that one of the first electrodes faces the opening; a second quartz crystal unit including a second electrode pair sandwiching the second quartz crystal plate and made of a second metal having a lower ionization tendency than the first metal, the second electrode pair being disposed inside the housing such that one of the second electrode pair faces the opening; a first frequency measurement circuit that outputs a resonance frequency of the first crystal resonator; a second frequency measurement circuit that outputs the resonance frequency of the second crystal resonator; A method for calculating the amount of pollutants using a pollutant detection sensor comprising: Calculating the amount of pollutants based on a calibration curve function that defines the relationship between the difference in frequency fluctuation between the first crystal oscillator and the second crystal oscillator and the amount of pollutants. A method for calculating the amount of polluting substances.

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