JP2022062304A - Hydrogen sulfide concentration estimation device, and detector of failure risk due to hydrogen sulfide - Google Patents

Abstract

To provide a hydrogen sulfide concentration estimation device capable of automatically and constantly monitoring a hydrogen sulfide concentration in an environment where electrical equipment is installed, and to provide a detector of a failure risk due to hydrogen sulfide that automatically and constantly monitors the progress of corrosion due to hydrogen sulfide and detects a risk that a failure occurs on a printed circuit board or the like due to corrosion.SOLUTION: A hydrogen sulfide concentration estimation device includes: a light reflection part 114 on which silver Ag is disposed; a light-emitting part 102 for irradiating the silver with light; a light detector 106 for detecting light reflected by the silver; a measuring terminal for generating a voltage according to current flowing in the light detector, in a state that the silver is irradiated with light from the light-emitting part; a measuring part for measuring a voltage of the measuring terminal; and a calculation part for calculating an estimated value of a hydrogen sulfide concentration in the peripheral environment of the light reflection part, on the basis of the voltage measured by the measuring part. Accordingly, the hydrogen sulfide concentration in the environment can be automatically and constantly monitored.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hydrogen sulfide concentration measuring device in an environment where hydrogen sulfide can be generated, and a hydrogen sulfide defect risk detecting device that detects the risk of a defect occurring in a printed substrate or the like due to corrosion by hydrogen sulfide.

Hydrogen sulfide is likely to be generated in sewerage treatment facilities and the like, and the metal parts (electrical wiring patterns, etc.) of printed substrates used in electrical equipment (including electrical equipment) are corroded by hydrogen sulfide. When the metal part of the printed circuit board is corroded by hydrogen sulfide, problems such as failure such as short circuit of adjacent wiring patterns occur. For the maintenance of installed electrical equipment, it is preferable to monitor the concentration of hydrogen sulfide in the installation environment and detect signs of malfunction due to corrosion caused by hydrogen sulfide.

Eco-Checker (registered trademark) II manufactured by Fujitsu Quality Lab Co., Ltd. is known as a method for diagnosing the presence or absence of corrosive substances in the atmosphere and the degree of corrosion thereof. It contains 5 types of test metal pieces (silver, copper, iron-nickel alloy, aluminum, iron). After exposing these metal pieces to the measurement environment for a certain period (1 month), the discoloration of the test metal pieces thereafter is compared with the color sample attached to the product to determine the presence or absence of corrosive gas and the approximate degree of corrosion. Judge (reference concentration). If the exposed metal pieces are sent to Fujitsu Quality Lab Co., Ltd. for analysis, for example, the results of quantitative analysis of the amount of silver corrosion by fluorescent X-ray analysis or the like will be reported.

Further, Patent Document 1 below discloses a corrosion environment monitoring device. This corrosive environment monitoring device constantly monitors the resistance of the printed circuit board pattern due to silver, and monitors the increase in resistance value due to the pattern corrosion (silver changes to silver oxide), thereby corrosive substances (sulfide) in the environment. Monitor the concentration of hydrogen) over a long period of time.

The following Patent Document 2 discloses an environmental measuring device for measuring corrosive gas in the atmosphere with high accuracy. This environmental measuring device detects the weight increase due to the sulfurization (sulfur content adhesion) of silver by the QCM (Quartz Crystal Microbalance) sensor. The QCM sensor is a mass sensor that utilizes the property that when the mass of the electrode of the crystal oscillator changes due to corrosion, the resonance frequency decreases according to the amount of corrosion.

The following Patent Document 3 discloses an environmental measuring device capable of accurately and easily measuring the concentration of a gas to be measured in a short time. Specifically, a sample of a metal thin film (for example, an alloy consisting of Cu-Ag-Sn) that changes color when exposed to a corrosive gas (for example, sulfite gas, hydrogen sulfide gas, chlorine gas, ammonia gas, nitrogen oxide gas). The degree of discoloration is photographed, and the intensity and proportion of the three color elements (red, blue, and green) are analyzed to estimate the corrosive gas concentration. For estimation, the degree of discoloration by testing with various gases is confirmed in advance.

Japanese Unexamined Patent Publication No. 2019-11433 International Publication No. 2013/186856 Japanese Unexamined Patent Publication No. 2011-196985

In the maintenance of electrical equipment installed in an environment where hydrogen sulfide can be generated, it is preferable that the concentration of hydrogen sulfide in the environment and the progress of corrosion due to hydrogen sulfide can be automatically and constantly monitored. However, in the method of fluorescent X-ray analysis after exposing the test metal piece for a predetermined period, there is a problem that the evaluation period including the exposure period takes one month or more. The evaluation result is the exposure result for one month, and can be said to be the average value for one month. Fluctuations in concentration within a one-month period cannot be evaluated. In addition, complicated work such as installation, collection, and evaluation of the test metal piece is required, which is troublesome and cannot be used for automatic continuous monitoring.

In Patent Document 1, the pattern cross section needs to be completely sulfurized in order for the resistance value of the silver pattern to be clearly increased. That is, when an increase in the resistance value of the silver pattern is detected, it can be said that a problem has already occurred. Therefore, the sensitivity is too low to detect a sign of failure due to corrosion of the printed circuit board.

Patent Document 2 requires a function of detecting fluctuations in the resonance frequency, and the equipment for that purpose is expensive. Further, since it reacts to the weight increase due to a phenomenon other than sulfurization (for example, moisture adhesion or oxidation due to high humidity), the accuracy is not sufficient as a method for detecting hydrogen sulfide.

In Patent Document 3, since the detection is performed by discoloration of the sample surface, the sensitivity is high and a plurality of gases can be evaluated. However, it is necessary to take a sample, decompose it into each color element, and perform an operation, which requires an expensive device. In addition, a dedicated alloy substrate is required for evaluation, and it is necessary to confirm the degree of discoloration by testing with various gases in advance, so that it cannot be used for automatic continuous monitoring.

Therefore, it is a first object of the present invention to provide a hydrogen sulfide concentration estimation device that can automatically and constantly monitor the hydrogen sulfide concentration in the environment in which an electric device is installed. The second aspect of the present invention is to provide a defect risk detection device using hydrogen sulfide, which can automatically constantly monitor the progress of corrosion caused by hydrogen sulfide and detect the risk of defects occurring on a printed substrate or the like due to corrosion. The purpose.

The hydrogen sulfide concentration estimation device according to the first aspect of the present invention has a reflective portion on which silver is arranged on the surface, a light emitting portion that irradiates light on silver arranged on the surface of the reflective portion, and a surface of the reflective portion. A light detection unit that detects the light reflected by the arranged silver, and a state in which the silver arranged on the surface of the reflection unit is irradiated with light from the light emitting unit, a voltage corresponding to the current flowing through the light detection unit is generated. It includes a measuring terminal, a measuring unit that measures the voltage of the measuring terminal, and a calculating unit that calculates an estimated value of the hydrogen sulfide concentration in the ambient environment of the reflecting unit based on the voltage measured by the measuring unit. As a result, the hydrogen sulfide concentration in the environment can be automatically and constantly monitored.

Preferably, in the first time series data composed of the voltages repeatedly measured by the measuring unit in a predetermined period, the first measured from one first voltage is K days before the first voltage is measured. The difference obtained by subtracting the two voltages is ΔY, the constant is L, the estimated value is C, the calculation unit calculates the estimated value by C = − (ΔY / K) / L, and L is the voltage. It is a value showing the magnitude of the inclination when the graph obtained by plotting the measurement data of the above is linearly approximated to the product of the hydrogen sulfide concentration at the time of measuring the voltage and the number of days elapsed from the start of the measurement. Thereby, the hydrogen sulfide concentration can be estimated accurately and easily.

More preferably, the measurement interval of the voltage is 1 minute or more and 1 hour or less, and the calculation unit obtains the second time series data composed of the moving median values determined from the first time series data. Estimated value is calculated by replacing with the time series data of, and the moving median value is the median value when the data in the continuous period of 12 hours or more and 2 days or less in the first time series data are arranged in order of size. be. As a result, the singular point appearing in the measurement data can be removed, so that the hydrogen sulfide concentration can be estimated more accurately.

More preferably, the reflective section includes two reflective surfaces that intersect in an L shape, and the light radiated from the light emitting section to one of the two reflective surfaces is reflected by one reflective surface and then the other. It is reflected by the reflecting surface, and at least a part of at least one of the two reflecting surfaces is silver-plated. As a result, the optical system including the light emitting unit and the photodetector unit can be made compact. Further, the area of the portion where the light from the light emitting portion is reflected can be increased, the influence of the discoloration of silver in a wider area can be reflected in the generated voltage, and the measurement data can be stabilized.

Preferably, the reflective section includes two reflective surfaces that intersect in an L shape, and the light emitted from the light emitting section to one of the two reflective surfaces is reflected by one reflective surface and then reflected by the other. Reflected by the surface, only one of the two reflective surfaces is silver-plated, and the remaining reflective surface is made of a material that is not corroded by hydrogen sulfide. As a result, it is possible to prevent the reflected light from becoming too small due to the corrosion of silver, so that the detection accuracy is improved.

More preferably, the hydrogen sulfide concentration estimation device includes a flat plate placed on the reflective portion, and the surface of the flat plate on the side not facing the reflective portion is silver-plated. As a result, when the silver plating of the flat plate is corroded and cannot be used for measurement, the flat plate can be easily replaced and the hydrogen sulfide concentration estimation can be restarted promptly.

The defect risk detection device due to hydrogen sulfide according to the second aspect of the present invention includes a reflective portion in which silver is arranged on the surface, a light emitting portion that irradiates light on the silver arranged on the surface of the reflective portion, and a reflective portion. A photodetector that detects light reflected by silver placed on the surface, and a voltage corresponding to the current flowing through the photodetector while the silver placed on the surface of the reflector is irradiated with light from the light emitting part. Based on the generated measurement terminal, the measurement unit that measures the voltage of the measurement terminal, and the voltage measured by the measurement unit, the risk of malfunction due to corrosion due to hydrogen sulfide in the printed substrate placed around the reflection unit is detected. Includes a detector to be used. As a result, the progress of corrosion of the printed circuit board can be automatically and constantly monitored, and the risk of defects due to corrosion can be detected.

Preferably, the detection unit detects the maximum point in the time series data composed of the voltage measured by the measurement unit in the predetermined period, and after the maximum point, whether or not the minimum point exists within the predetermined observation period. It is determined that the risk has been detected based on the determination that the minimum point does not exist within the observation period, and the observation period is 20 days or more and 30 days or less. As a result, it is possible to detect a sign of a problem before it occurs due to corrosion of the printed circuit board.

According to the present invention, the hydrogen sulfide concentration in the environment in which the electric device is installed can be automatically and constantly monitored. In addition, the progress of corrosion caused by hydrogen sulfide can be automatically and constantly monitored, and signs of problems can be detected before they occur.

FIG. 1 is a block diagram showing a schematic configuration of a hydrogen sulfide concentration estimation device according to the first embodiment of the present invention. FIG. 2 is a circuit diagram showing a photodetection system of the hydrogen sulfide concentration estimation device shown in FIG. FIG. 3 is a flowchart showing a hydrogen sulfide concentration estimation process executed by the hydrogen sulfide concentration estimation device shown in FIG. FIG. 4 is a cross-sectional view showing the arrangement of the photodetection system according to the first modification. FIG. 5 is a cross-sectional view showing the arrangement of the photodetection system according to the second modification. FIG. 6 is a cross-sectional view showing the arrangement of the photodetection system according to the third modification. FIG. 7 is a graph showing the results of exposing a printed circuit board to an environment having various hydrogen sulfide concentrations. FIG. 8 is a block diagram showing a schematic configuration of a defect risk detection device due to hydrogen sulfide according to a second embodiment of the present invention. FIG. 9 is a circuit diagram showing an optical detection system of the failure risk detection device shown in FIG. FIG. 10 is a flowchart showing a defect risk detection process due to hydrogen sulfide executed by the defect risk detection device shown in FIG. FIG. 11 is a flowchart showing the risk determination process shown in FIG. FIG. 12 is a graph showing measurement results in an environment of different hydrogen sulfide concentrations by a hydrogen sulfide concentration estimator. FIG. 13 is a graph showing the measurement data shown in FIG. 12 with the product of the hydrogen sulfide concentration and the number of days as the horizontal axis. FIG. 14 is a graph showing the results of estimating the hydrogen sulfide concentration from the measurement data by the hydrogen sulfide concentration estimation device shown in FIG. FIG. 15 is a graph showing measurement results by a defect risk detection device in an environment of high concentration hydrogen sulfide. FIG. 16 is a graph showing the measurement data shown in FIG. 15 with the product of the hydrogen sulfide concentration and the number of days as the horizontal axis. FIG. 17 is a graph showing the slope obtained from the measurement data shown in FIG.

In the following embodiments, the same parts are given the same reference numbers. Their names and functions are also the same. Therefore, detailed explanations about them will not be repeated.

(First Embodiment)
(Configuration of hydrogen sulfide concentration estimation device)
With reference to FIG. 1, the hydrogen sulfide concentration estimation device 100 according to the first embodiment of the present invention has a light emitting unit 102 that emits light, a power supply unit 104 that supplies power to the light emitting unit 102, and light. It includes a light detection unit 106 for detection, a control unit 108, a storage unit 110, a timer 112, and a light reflection unit 114. The hydrogen sulfide concentration estimation device 100 also includes a power source (not shown) for operating each part, and an operating device (not shown) such as a computer keyboard and a mouse for inputting an instruction to the control unit 108. .. The light emitting unit 102, the light detecting unit 106, and the light reflecting unit 114 are arranged in an electric device installed in an environment where hydrogen sulfide can be generated. The light emitted from the light emitting unit 102 may be detected by the light detecting unit 106, and the light emitting unit 102, the light detecting unit 106, and the light reflecting unit 114 may be ambient light. It suffices if it is placed in an environment that can shield the light. The location of the power supply unit 104, the control unit 108, the storage unit 110, and the timer 112 is arbitrary, and may be arranged inside the electric device to be monitored or outside the electric device.

The light emitting unit 102 is realized by, for example, a light emitting diode (hereinafter referred to as LED). The light emitting unit 102 is not limited to the LED, and may be any light emitting element capable of stably outputting light of a predetermined intensity in a predetermined direction for a predetermined time (for example, about 0.1 to several seconds). The wavelength of the synchrotron radiation of the light emitting unit 102 may be any wavelength as long as it can be detected by the photodetection unit 106. The synchrotron radiation of the light emitting unit 102 is, for example, visible light, infrared rays, ultraviolet rays, or the like. Under the control of the control unit 108, the power supply unit 104 supplies electric power for lighting the light emitting unit 102 to the light emitting unit 102.

The photodetector 106 is realized by, for example, a phototransistor. The photodetector 106 is not limited to a phototransistor, and may be any element that can detect light and output an electric signal (for example, voltage, current) having a magnitude corresponding to the intensity (light amount) thereof. The photodetector 106 preferably has the center wavelength of the synchrotron radiation of the light emitting unit 102 near the center of the detection sensitivity.

The light reflecting portion 114 includes an L-shaped member 116 and silver Ag. Silver Ag is arranged on two orthogonal surfaces 120 and 122 on the light emitting portion 102 side of the L-shaped member 116. Silver Ag may be arranged on the entire surface of the surfaces 120 and 122, or silver Ag may be arranged on a part thereof. For example, the surfaces 120 and 122 are silver plated. As a result, as shown by the dotted line in FIG. 1, the light emitted from the light emitting unit 102 is reflected by the silver Ag and incident on the photodetector unit 106. The L-shaped member 116 is formed in an L-shaped cross section, and the optical path from the light emitting unit 102 to the photodetection unit 106 can be accommodated in a relatively narrow space. The L-shaped member 116 may be arranged so that the two surfaces 120 and 122 form an approximately 90 °, and the L-shaped member means that such a shape is also included. For example, the L-shaped member 116 can be formed by bending a metal plate. The L-shaped member 116 may be formed by joining two flat members so as to be substantially orthogonal to each other. The light emitting unit 102, the light detection unit 106, and the light reflection unit 114 constitute a light detection system.

The light emitting unit 102 and the photodetector unit 106 can be realized by, for example, a photoreflector which is an element in which an LED and a phototransistor are housed in one package. As a result, the number of parts can be reduced and the photodetection system can be compactly formed.

The control unit 108 is a CPU (Central Processing Unit), and controls the output of the power supply unit 104 to turn on or off the light emitting unit 102. For example, when the control unit 108 outputs a high level (for example, 5V) signal to the power supply unit 104, the power supply unit 104 supplies electric power to the light emitting unit 102. As a result, the light emitting unit 102 is turned on. When the control unit 108 outputs a low level (for example, 0V) signal to the power supply unit 104, the power supply unit 104 stops supplying power to the light emitting unit 102. As a result, the light emitting unit 102 that was lit is turned off.

Further, the control unit 108 acquires the output signal of the photodetection unit 106 at a predetermined timing. For example, if the photodetector 106 has an A / D conversion function, the control unit 108 acquires digital data output from the photodetector 106. When the optical detection unit 106 outputs an analog signal, the control unit 108 samples the input analog signal at predetermined time intervals to generate digital data.

The storage unit 110 is a volatile or non-volatile memory that stores data input from the control unit 108. The timer 112 receives a request from the control unit 108 and outputs the current time.

As described above, the light emitted from the light emitting unit 102 is reflected by the silver Ag on the surface 120, is reflected again by the silver Ag on the surface 122, and returns to be substantially parallel to the optical axis of the light emitting unit 102, and the light is detected. It is detected by unit 106. The amount of light measured by the photodetector 106 changes according to the state of silver Ag in the photoreflection unit 114. When silver Ag is corroded by hydrogen sulfide, the reflectance of light decreases, so that the measured value becomes smaller. The degree of corrosion of the silver Ag of the light reflecting portion 114 increases with the hydrogen sulfide concentration in the surrounding environment and the passage of time after the light reflecting portion 114 is installed in the electric device. Therefore, if the amount of light detected by the photodetection unit 106 is measured while the power supply unit 104 is controlled by the control unit 108 to light the light emitting unit 102, the change in the corrosion state of silver Ag can be observed. can.

FIG. 2 shows an example of a circuit of a photodetection system using an LED for the light emitting unit 102 and a phototransistor for the photodetection unit 106. With reference to FIG. 2, the light emitting unit 102 includes an LED 130 and a resistor R1 connected in series between the terminals 140 and 142. In FIG. 2, the silver Ag of the light reflecting portion 114 is shown by a flat plate for convenience. The photodetector 106 includes a phototransistor 132, resistors R2 and R3 connected in series between the terminals 144 and 146. With the terminals 142 and 146 grounded, the LED 130 radiates light by applying a DC voltage from the power supply unit 104 between the terminals 140 and 142 of the light emitting unit 102. When a predetermined DC voltage is applied between the terminals 144 and 146 and light (radiated light of the light emitting unit 102 reflected by silver Ag) is incident on the phototransistor 132, the photodetector 106 is the phototransistor 132. Turns on and current flows (current flows between terminals 144 and 146). The control unit 108 measures the voltage generated at the measurement terminal 134 (hereinafter referred to as the generated voltage) due to the voltage drop accompanying the voltage drop. Since the current value flowing through the phototransistor 132 depends on the amount of light incident on the phototransistor 132, the generated voltage measured at the measurement terminal 134 represents the amount of light incident on the phototransistor 132. The resistors R1, R2 and R3 may have appropriate resistance values according to the LED 130 and the phototransistor 132. The resistors R1, R2 and R3 may be variable resistors.

(Estimation method of hydrogen sulfide concentration)
The circuit shown in FIG. 2 is installed in an environment where hydrogen sulfide can be generated, the generated voltage is measured at a predetermined timing, and time-series data is acquired. For example, as an example, data as shown in FIG. 11 described later is acquired. At the start of measurement, the silver Ag of the light reflecting portion 114 is in an uncorroded state (hereinafter, also referred to as an initial state). Let Y (T) be the generated voltage measured at the elapsed time T (unit is day) from the start of measurement, and calculate the estimated value C (unit is ppb) of hydrogen sulfide concentration by the following equation.
C =-(ΔY / ΔT) / L ... (Equation 1)

In Equation 1, ΔY (day) is the difference between the elapsed voltage T and T−ΔT, that is, ΔY = Y (T) −Y (T—ΔT), and L is a constant. As will be described later as an example, the graph of the generated voltage with respect to the concentration / day product can be approximated by a straight line in the range where the concentration / day product is relatively small, and its slope (corresponding to the coefficient L) is a constant value. Equation 1 is based on this finding.

The generated voltage Y may be evaluated as a relative value. For example, the circuit of FIG. 2 is adjusted so that the value of the generated voltage Y measured in the initial state of the silver Ag of the light reflecting portion 114 becomes “130”. In the case, L = 0.075. The adjustment of the circuit of FIG. 2 is performed by adjusting the value of any one of the resistors R1 to R3.

In order to say that the estimated value C obtained by Equation 1 is valid (representing the hydrogen sulfide concentration), the product S of the hydrogen sulfide concentration (ppb) and the elapsed time (days) will be described later. Must be less than or equal to a predetermined threshold. As described above, when the circuit of FIG. 2 is adjusted so that the generated voltage Y measured in the initial state of the silver Ag of the light reflecting portion 114 becomes “130”, the threshold value is 1300 (ppb. Day), and it is necessary that S ≦ 1300. In the period when S exceeds the threshold value (S> 1300), the estimated value C calculated by Equation 1 is not valid (does not represent the hydrogen sulfide concentration).

(Estimation operation of hydrogen sulfide concentration)
Hereinafter, the process of estimating the estimated value of the hydrogen sulfide concentration in the installation environment of the electric device will be described with reference to FIG. 3 by the hydrogen sulfide concentration estimation device 100 of FIG. The process shown in FIG. 3 is performed by the control unit 108 reading and executing a predetermined program stored in the storage unit 110 in advance. The light emitting unit 102 and the photodetector unit 106 constitute the circuit shown in FIG. 2, and the photodetector system of the hydrogen sulfide concentration estimation device 100 is a darkness inside an electric device (switching board or the like) (external light does not enter). Place). Further, it is assumed that the circuit of FIG. 2 is preliminarily adjusted so that the generated voltage measured in the initial state of the silver Ag of the light reflecting portion 114 becomes “130”.

Information for specifying the time to execute the measurement (hereinafter referred to as measurement time information), a predetermined threshold value Th1, parameters of the formula 1 (L, K (day)), and a message are stored in the storage unit 110. Suppose it is remembered. The measurement time information may be specified according to the timing at which the measurement is performed, and is arbitrary. For example, when the measurement is performed at a fixed time interval, the measurement time information may be the start time and the time interval Δt. When the measurement is performed at a time specified in advance, the measurement time information may be any information that directly represents the time. Here, it is assumed that the measurement is performed every hour (Δt = 1 (hour)).

Since the circuit shown in FIG. 2 has been adjusted in advance as described above, L = 0.075. K corresponds to ΔT in Equation 1 and represents the difference in elapsed time on a daily basis. Here, it is assumed that two values of K = 3 (day) and K = 10 (day) are stored in the storage unit 110. The threshold Th1 is used to determine whether the calculated value is valid as an estimate of hydrogen sulfide. Since the circuit of FIG. 2 is preliminarily adjusted as described above, Th1 = 1300 (ppb · day).

In step 300, the control unit 108 acquires the current time from the timer 112, refers to the measurement time information stored in the storage unit 110, and determines whether or not the measurement time has come. If it is determined that the measurement time has come, the control shifts to step 302. Otherwise, control proceeds to step 322.

In step 302, the control unit 108 lights the light emitting unit 102 and measures the generated voltage of the measurement terminal 134. The measured generated voltage is stored in the storage unit 110 in correspondence with the elapsed time T from the start of measurement. After that, the control unit 108 turns off the light emitting unit 102, and the control shifts to step 304. Since step 302 is repeatedly executed, a series of time-series data is stored in the storage unit 110.

In step 304, the control unit 108 determines whether or not the singularity can be removed. If it is determined that the removal is possible, the control shifts to step 306. Otherwise, control proceeds to step 322. If the door is opened when inspecting electrical equipment, light from the outside may enter the inside of the equipment, and the light detection system may also be illuminated. In such a state, when the measurement is executed at the measurement timing of the generated voltage, the measured value becomes larger than the original value. In addition, the measured value may be smaller than the original value due to dew condensation or the like. In order to accurately estimate the hydrogen sulfide concentration, it is preferable to remove these measurement abnormal values as singular points. To remove the singularity, for example, the median movement can be used as the representative value. Specifically, in the time series data, the value (median value) located at the center when a predetermined number of consecutive data (for example, 25 (for example, the number of measurements in 24 hours)) are arranged in order of size is represented. Let it be a value. That is, since a predetermined number of measurement data is required to calculate the median movement, it is not determined that the singular point is removed until a predetermined number of measurement data is obtained.

In step 306, the control unit 108 removes the singularity from the series of time series data measured in step 302. Specifically, the control unit 108 obtains a moving center value for a predetermined number of consecutive past measurement data from the latest measurement data (data measured by executing step 302 at the end), and the moving center. The value is stored in the storage unit 110 in association with the measurement time of the latest measurement data. After that, control shifts to step 308. As described above, once the process of obtaining the moving median becomes possible, step 308 is executed every time new measurement data is acquired. Therefore, the time-series data in which the singularity is removed from the time-series data measured in step 302 is stored in the storage unit 110. The data (generated voltage) from which the singularity has been removed is represented by Y (T).

In step 308, the control unit 108 determines whether or not to execute the hydrogen sulfide concentration estimation process. The estimation process may be executed at the same interval (for example, 1 hour) as the data measurement timing, or may be executed at a different time interval (for example, 1 day). If it is determined to perform the estimation, control proceeds to step 310. Otherwise, control proceeds to step 322. As will be described later, in order to execute the hydrogen sulfide concentration estimation process, measurement data exceeding K days is required. Therefore, it is not determined that the hydrogen sulfide concentration estimation process is executed until the measurement data for more than K days is stored in the storage unit 110.

In step 310, the control unit 108 reads one K from the storage unit 110. After that, control shifts to step 312.

In step 312, the control unit 108 identifies one data from the data Y (T) from which the singularity stored in the storage unit 110 has been removed, and the data Y (TK) K days before the data Y (T). ) Is specified, and the difference ΔY (T) = Y (T) −Y (TK) between the two data is calculated. The control unit 108 stores the calculated ΔY (T) in the storage unit 110. Since the process of step 312 is repeatedly executed, the data at the time when the hydrogen sulfide concentration has already been estimated using the same K is excluded. After that, control shifts to step 314. In order to calculate the difference ΔY (T), measurement data exceeding K days is required.

In step 314, the control unit 108 reads ΔY (T) calculated in step 314 from the storage unit 110, calculates C (T) by the above equation 1, and uses it as an estimated value of the hydrogen sulfide concentration at the elapsed time T. , Stored in the storage unit 110. After that, control shifts to step 316. As a result, the time-series data of the estimated value C (T) of the hydrogen sulfide concentration at the measurement time (elapsed time T) is stored in the storage unit 110.

In step 316, the control unit 108 determines whether or not the estimation process is completed. As described above, since the storage unit 110 stores two Ks, it is determined that the two Ks have been completed after the steps 310 to 314 have been executed for each K. Otherwise, control returns to step 310, and the control unit 108 reads another K from the storage unit 110 and executes steps 312 and 314. As a result, the time-series data of the estimated value C (T) of the hydrogen sulfide concentration is stored in the storage unit 110 for each K.

In step 318, the control unit 108 determines whether or not the data (generated voltage) Y stored in the storage unit 110 after the last step 306 is executed is larger than the threshold value Th1 (for example, 30). If the data Y is determined to be greater than the threshold Th1, control proceeds to step 322. Otherwise, control proceeds to step 320.

Step 318 is a process for determining the validity of the calculated estimated value of hydrogen sulfide concentration. As described above, in order for the estimated value of hydrogen sulfide concentration calculated by Equation 1 to be valid, it is necessary that the concentration / day product S is S ≦ 1300. Therefore, the concentration / day product S may be repeatedly calculated and the calculated value S and the threshold value (for example, 1300) may be compared, but here, a simpler method is used. When Equation 1 is modified, C × ΔT × L = −ΔY. Assuming that C × ΔT = 1300 (threshold value that determines the concentration measurable range) and L = 0.075, −ΔY = 1300 × 0.075 = 97.5 (about 100). That is, when the concentration / day product reaches 1300, it can be said that the measured value Y is about 100 lower than the generated voltage in the initial state of silver Ag. Since the value of the generated voltage in the initial state of silver Ag is 130, it can be said that the concentration / day product exceeds 1300 if the measured value Y drops to 30 (= 130-100). Therefore, in step 318, the validity of the calculated estimated value of hydrogen sulfide concentration can be determined by comparing the data (median movement) determined in step 306 with the threshold value Th1 (= 30).

Before moving to step 322, the control unit 108 presents time-series data of the estimated value C (T) of the hydrogen sulfide concentration. For example, in order to monitor the hydrogen sulfide concentration, the latest hydrogen sulfide concentration is presented numerically. In addition, time-series data of hydrogen sulfide concentration may be presented as a graph. As described above, if the determination result in step 318 is YES (Y> 30), the concentration / day product Si is 1300 or less, and the calculated C (T) is effective as an estimated value of the hydrogen sulfide concentration. Therefore, the user (administrator) can appropriately take measures for equipment maintenance according to the change in the hydrogen sulfide concentration.

In step 320, the control unit 108 reads a predetermined message from the storage unit 110 and presents it. As described above, if Y> Th1, the silver Ag of the light reflecting portion 114 is corroded, and the calculated C (T) is not effective as an estimated value of the hydrogen sulfide concentration. Therefore, for example, it is suggested that the light reflecting unit 114 needs to be replaced in order to continue the measurement. If the hydrogen sulfide concentration estimation device 100 includes an acoustic output device or an image display device, the message can be presented as an acoustic or an image. Data representing a message to be presented may be output from the hydrogen sulfide concentration estimation device 100 to an external acoustic output device or image display device.

In step 322, the control unit 108 determines whether or not the end instruction has been received. If you are instructed to end, this program will end. If not, control returns to step 300 and repeats the above process. The end instruction is given, for example, by turning off the power of the hydrogen sulfide concentration estimation device 100.

As a result, it becomes possible to constantly monitor the hydrogen sulfide concentration in the environment in which the electronic device is installed. That is, the amount of light (voltage generated at the measurement terminal 134) detected by the photodetection unit 106 changes according to the corrosion state of the silver Ag of the light reflection unit 114. Therefore, the hydrogen sulfide concentration estimation device 100 repeats the measurement of the voltage generated at the measurement terminal 134 by turning on the light emitting unit 102 at a predetermined timing for a predetermined period, thereby using the equation 1 to obtain light. The hydrogen sulfide concentration in the surrounding environment of the electric device in which the reflecting unit 114 is arranged can be automatically estimated. It is good to present an estimated value of hydrogen sulfide concentration, it is possible to take measures before the performance deterioration, failure, etc. of the electric equipment occur, and the electric equipment can be managed appropriately.

The hydrogen sulfide concentration estimation device 100 has a relatively simple device configuration and can be realized as an inexpensive device. By silver-plating the L-shaped member 116, the light reflecting portion 114 can be realized easily and inexpensively.

By forming the light reflecting portion 114 in an L shape, the light detection system can be compactly formed as described above. Further, since the light from the light emitting unit 102 is obliquely incident on the reflecting surface of the light reflecting unit 114, the area of the portion where the light is reflected can be increased. Since the influence of the discoloration of silver Ag in a wider area can be reflected in the generated voltage, the measurement data is stable.

By observing the corrosion of silver Ag as a change in the reflectance of light (change in the generated voltage), the hydrogen sulfide concentration can be estimated accurately. Since the measurement result (generated voltage) is an electric signal, remote monitoring is easily possible. Further, the hydrogen sulfide concentration estimation device 100 presents a message or the like that the light reflecting unit 114 needs to be replaced if the calculated estimated value becomes invalid. Therefore, the light reflecting unit 114 can be replaced only by replacing the light reflecting unit 114. Observation can be easily continued, and the estimation accuracy of hydrogen sulfide concentration can be maintained at a high level.

The above-mentioned values of the coefficients L and K (= ΔT) are examples, and are not limited to the above-mentioned values. If the circuit of FIG. 2 is adjusted in advance so that the generated voltage measured in the initial state of the silver Ag of the light reflecting portion 114 becomes a value other than “130”, the coefficient L becomes a value different from the above. Further, for example, K (day) may be a real number between 1 and 15 depending on the hydrogen sulfide concentration in the environment. Further, the threshold value Th1 for determining the validity of the estimated value is not limited to the above value. When higher accuracy is required, a value larger than the above value may be used as the threshold value Th1.

In the above, the case where two Ks are used has been described, but the present invention is not limited to this. You may use 3 or more Ks. If the high or low hydrogen sulfide concentration is known to some extent in advance, one K may be set accordingly.

Further, the measurement time interval and the number of data used for calculating the median movement are not limited to the above values. The measurement time interval is a value of 1 minute or more and 1 hour or less, and the number of data used for calculating the median movement may be data measured during half a day or more and 2 days or less.

In the above, the case where the median movement is used to remove a specific point from the measurement data has been described, but the present invention is not limited to this. For example, the moving average value may be used instead of the moving median value. Further, instead of a simple moving average value, a plurality of consecutive measurement data may be arranged in descending order and the average value near the center thereof may be used. For example, when 25 consecutive measurement data are targeted, the average value of the 11th to 15th measurement data can be used.

In the above, in step 318, when the measurement data Y (after removing the singular point) is not larger than the threshold value Th1 (for example, 30), it is determined that the estimated value of the hydrogen sulfide concentration is not valid, but the present invention is limited to this. Not done. A value calculated from the measurement data Y (after removing the specific point) may be used. For example, if the ratio (Y / 130) of the measured value Y to the initial value (130) of the generated voltage is not larger than a predetermined value (for example, 30/130≈0.23), the estimated value of the hydrogen sulfide concentration is not valid. It can also be determined that.

(First modification)
In the above, the case where the silver Ag is arranged on the surfaces 120 and 122 of the L-shaped member 116 to reflect the synchrotron radiation of the light emitting unit 102 has been described, but the present invention is not limited to this. As shown in FIG. 4, silver Ag may be arranged only on one surface of the surfaces 120 and 122. For example, FIG. 4A shows a configuration in which silver Ag is arranged (for example, silver-plated) on a horizontal surface 120. Silver Ag may be arranged on the entire surface of the surface 120, or silver Ag may be arranged on a part of the surface 120. FIG. 4B shows a configuration in which silver Ag is arranged (for example, silver-plated) on a vertical surface 122. Silver Ag may be arranged on the entire surface of the surface 122, or silver Ag may be arranged on a part of the surface 122. In any of the cases (a) and (b) of FIG. 4, it is preferable that the surface on which the silver Ag is not arranged is mirror-finished so as to reflect light and is not corroded by hydrogen sulfide.

(Second modification)
In the above, the case where the silver Ag is directly arranged on the surface of the L-shaped member 116 has been described, but the present invention is not limited to this. It may be configured by using a silver-plated flat plate. For example, as shown in FIG. 5, the silver-plated plate 124 can be arranged on the L-shaped member 116. It is preferable that the surface 122 on which the silver Ag is not arranged is mirror-finished so as to reflect light and is not corroded by hydrogen sulfide. With such a configuration, as described above, when the concentration / day product exceeds the threshold value and it is determined that the calculated estimated value C is not valid, it is easy to simply replace the silver-plated plate 124. Measurement can be resumed.

(Third modification example)
In the above, the case where the L-shaped member 116 having an L-shaped cross section and the light reflecting portion 114 including the silver Ag are used has been described, but the present invention is not limited thereto. As shown in FIG. 6, a light reflecting unit 118 including a flat plate 126 and silver Ag may be used instead of the light reflecting unit 114. Silver Ag is arranged (for example, silver-plated) on one plane of the flat plate 126, and the light emitted from the light emitting unit 102 is reflected once by the silver Ag and detected by the light detection unit 106.

As in the second modification and the third modification, when the synchrotron radiation of the light emitting unit 102 is reflected only once by the silver Ag, the amount of attenuation of the reflected light becomes too small when the silver Ag is corroded and discolored. Can be suppressed. When the synchrotron radiation of the light emitting unit 102 is reflected twice by the corroded and discolored silver Ag (silver sulfide), the amount of light incident on the light detection unit 106 becomes too small. Therefore, the generated voltage to be measured becomes too small, and the measurement accuracy is lowered. By configuring as in the second modification and the third modification, the decrease in measurement accuracy can be suppressed, and the decrease in accuracy of the estimated value of hydrogen sulfide concentration can be suppressed.

(Fourth modification)
In FIGS. 1, 4 and 5, the case where the photodetector 106 is arranged above the light emitting unit 102 has been described, but the present invention is not limited to this. In FIGS. 1, 4 and 5, the positions of the light emitting unit 102 and the light detecting unit 106 may be exchanged, and the light emitting unit 102 may be arranged above the light detecting unit 106.

(Second embodiment)
The following (1) and (2) are known as typical defects that occur when a printed circuit board is exposed to hydrogen sulfide.
(1) Copper sulfide propagates (corrosion progresses) from the printed circuit board pattern (wiring, lands, etc.) to the surroundings, reaches the adjacent pattern, and short-circuits.
(2) The entire cross section inside the pattern of the printed circuit board is sulfurized, and the resistance value of that portion increases.
As a result of investigating past defects, it was confirmed that the defect (1) occurs before the defect (2) in most cases. Therefore, it is preferable if the sign of the defect (1) can be detected before it occurs. In the second embodiment, there is a problem (1) such as a short circuit of wiring due to corrosion of a printed substrate or the like included in an electric device or the like installed in an environment where hydrogen sulfide can be generated by hydrogen sulfide. The purpose is to detect the risk that occurs (hereinafter referred to as the risk of malfunction due to hydrogen sulfide).

FIG. 7 shows the degree of corrosion of the printed circuit board in a hydrogen sulfide environment. Specifically, the simulated printed circuit board was exposed to a plurality of hydrogen sulfide environments having different concentrations, and the corrosion progress distance was measured according to the elapsed time from the start of exposure. The vertical axis is the corrosion progress distance (μm), and the horizontal axis is the product of the hydrogen sulfide concentration at the time of measuring the corrosion progress distance and the number of days elapsed from the start of exposure to the time of measurement (concentration / days product (ppb / day)). )).

Normally, the distance between patterns of printed wiring is 100 μm or more, so if the corrosion progress distance is up to about 20 μm, insulation deterioration (short circuit, etc.) does not occur. That is, as shown by the downward arrow in FIG. 7, if the corrosion progress distance is 20 μm or less, it is considered that there is no risk of occurrence of a defect. On the other hand, as shown by the upward arrow, when the corrosion progress distance is 50 μm or more, the risk of occurrence of a defect increases. From the measurement results shown in FIG. 7, it can be seen that if the concentration / day product is about 15,000 ppb / day or less, the corrosion progress distance is 20 μm or less (see the shaded area). Therefore, in anticipation of safety, it is preferable to be able to detect the time when the concentration / day product becomes about 10,000 ppb / day.

The hydrogen sulfide concentration is calculated in the same manner as in the first embodiment (see step 314 in FIG. 3), the concentration / day product is calculated using it, and the value is set to a predetermined threshold value Th2 (for example, 10000 (for example, 10000 (for example)). By comparing with ppb ・ day)), it is conceivable to detect a sign of failure risk. However, as described above, the hydrogen sulfide concentration can be calculated accurately only when the concentration / day product is about 1300 ppb / day. On the other hand, as will be described later, in the second embodiment, the sign of the risk of failure can be automatically detected without calculating the hydrogen sulfide concentration in the environment in which the electric device is installed.

(Configuration of defect risk detection device)
With reference to FIG. 8, the defect risk detection device 200 according to the second embodiment of the present invention detects light, a light emitting unit 202 that emits light, a power supply unit 104 that supplies power to the light emitting unit 202, and light. It includes a light detection unit 206, a control unit 208, a storage unit 110, a timer 112, and a light reflection unit 114. In the defect risk detection device 200, in the hydrogen sulfide concentration estimation device 100 shown in FIG. 1, the light emitting unit 102, the photodetector 106, and the control unit 108 are replaced by the light emitting unit 202, the photodetector 206, and the control unit 208, respectively. It is a thing. The configuration other than the light emitting unit 202, the photodetector unit 206, and the control unit 208 is the same as that of the hydrogen sulfide concentration estimation device 100. Therefore, in the following, the duplicate explanation will not be repeated, and the differences will be mainly described.

The light emitting unit 202 is realized by, for example, an LED. The light emitting unit 202 is not limited to the LED, and may be any light emitting element capable of stably outputting light of a predetermined intensity in a predetermined direction for a predetermined time (for example, about 0.1 to several seconds). The light emitting unit 202 emits red light (for example, the center wavelength of light is 630 nm).

The photodetector 206 is realized by, for example, a phototransistor. The photodetector 206 is not limited to the phototransistor, and may be any element that can detect the synchrotron radiation of the light emitting unit 202 and output an electric signal (for example, voltage, current) having a magnitude corresponding to the intensity (light amount) thereof. The photodetector 206 preferably has a center wavelength of 630 nm of the synchrotron radiation of the light emitting unit 202 near the center of the detection sensitivity.

The light emitting unit 202, the light detecting unit 206, and the light reflecting unit 114 constitute a light detecting system. The photodetector system of the failure risk detection device 200 is arranged near the printed circuit board 900 in the electrical equipment. The detection system of the failure risk detection device 200 is realized by the same circuit as the detection system of the hydrogen sulfide concentration estimation device 100. FIG. 9 shows an example of a circuit of a photodetection system using an LED for the light emitting unit 202 and a phototransistor for the photodetection unit 206. FIG. 9 is a circuit similar to that of FIG. In FIG. 9, unlike FIG. 2, the LED 230 emits red light, and the phototransistor 232 detects the red light emitted from the LED 230.

The control unit 208 is a CPU like the control unit 108 of the hydrogen sulfide concentration estimation device 100, controls the output of the power supply unit 104, controls the lighting of the light emitting unit 202, and detects the light by the photodetection unit 206. do. The difference between the control unit 208 and the control unit 108 is that the control unit 108 calculates the estimated value of the hydrogen sulfide concentration, whereas the control unit 208 detects the risk of malfunction due to hydrogen sulfide.

(Failure risk detection operation)
Hereinafter, with reference to FIG. 10, a process for detecting a defect risk due to hydrogen sulfide in a printed circuit board of an electric device, which is executed by the defect risk detection device 200 of FIG. 8, will be described. As described above, the risk of malfunction due to hydrogen sulfide is detected by detecting the time when the concentration / day product reaches about 10,000 ppb / day. As will be described later as an example, when the hydrogen sulfide concentration / day product reaches about 10,000 (ppb / day), a maximum point appears in the graph of the generated voltage measured by irradiating with red light, and then it occurs. It was found that the voltage decreased over 20-30 days. Based on this, by detecting this maximum point, it is detected that the concentration / day product of hydrogen sulfide has reached about 10,000.

The process shown in FIG. 10 is performed by the control unit 208 reading and executing a predetermined program stored in the storage unit 110 in advance. The light emitting unit 202 and the photodetector unit 206 form the circuit shown in FIG. 9, and the photodetector system of the defect risk detection device 200 is a dark place inside an electric device (switchboard or the like) (a dark place where external light does not enter). ). Further, it is assumed that the circuit of FIG. 9 is preliminarily adjusted so that the generated voltage measured in the initial state of the silver Ag of the light reflecting portion 114 becomes “130”.

It is assumed that the measurement time information, parameters (L, K (days)) and messages are stored in the storage unit 110 of the failure risk detection device 200, as in the hydrogen sulfide concentration estimation device 100. Here, it is assumed that the measurement is performed every hour (Δt = 1 (hour)). L and K are 0.075 and 10 (days), respectively. The content of the message is different from that of the hydrogen sulfide concentration estimation device 100 as described later.

In step 400, the control unit 208 acquires the current time from the timer 112, refers to the measurement time information stored in the storage unit 110, and determines whether or not the measurement time has come. If it is determined that the measurement time has come, the control shifts to step 402. Otherwise, control proceeds to step 422.

In step 402, the control unit 208 lights the light emitting unit 202 and measures the generated voltage of the measurement terminal 134. The measured generated voltage is stored in the storage unit 110 in correspondence with the elapsed time T from the start of measurement. After that, the control unit 208 turns off the light emitting unit 202, and the control shifts to step 404. Since step 402 is repeatedly executed, a series of time-series data is stored in the storage unit 110.

In step 404, the control unit 208 determines whether or not the singularity can be removed, as in step 304 (see FIG. 3). If it is determined that it can be removed, control shifts to step 406. Otherwise, control proceeds to step 422.

In step 406, the control unit 208 removes the singularity from the series of time series data measured in step 402, as in step 306 (see FIG. 3). After that, control shifts to step 408. As a result, the time-series data in which the singularity is removed from the time-series data measured in step 402 is stored in the storage unit 110. The data (generated voltage) from which the singularity has been removed is represented by Y (T).

In step 408, the control unit 208 determines whether or not to execute the risk determination process. The risk determination process may be executed at the same interval (for example, 1 hour) as the data measurement timing, or may be executed at a different time interval (for example, 1 day). If it is determined to execute the risk detection process, control shifts to step 410. Otherwise, control proceeds to step 422. As will be described later, in order to execute the risk determination process, measurement data exceeding K days is required. Therefore, it is not determined that the risk determination process is executed until the measurement data for more than K days is stored in the storage unit 110.

In step 410, the control unit 208 reads K from the storage unit 110. After that, control shifts to step 412.

In step 412, the control unit 208 identifies one data from the data Y (T) from which the singularity stored in the storage unit 110 has been removed, and the data Y (TK) K days before the data Y (T). ) Is specified, and the difference ΔY (T) = Y (T) −Y (TK) between the two data is calculated. The control unit 208 stores the calculated ΔY (T) in the storage unit 110. After that, control shifts to step 414. In order to calculate the difference ΔY (T), measurement data exceeding K days is required.

In step 414, the control unit 208 reads the ΔY (T) calculated in step 414 and the coefficient L from the storage unit 110, and calculates the slope α (T) by the following equation.
α (T) =-(ΔY (T) / K) / L ... (Equation 2)
The control unit 208 calculates α (T) for each elapsed time T and stores it in the storage unit 110. After that, control shifts to step 416. As a result, the time series data of α (T) at the elapsed time T is stored in the storage unit 110. Although step 414 is repeatedly executed, α (T) is calculated using the newly measured data, and the calculated α (T) is not calculated again.

In step 416, the control unit 208 executes the risk determination process. Specifically, the control unit 208 executes the process shown by the flowchart of FIG.

In step 500, the control unit 208 detects the maximum point from the Y (T) stored in the storage unit 110, and leaves only the information for specifying the latest maximum point. Specifically, the control unit 208 reads the time-series data of the slope α (T) from the storage unit 110, and the sign of α (T) (hereinafter referred to as polarity) changes from positive (plus) to negative (minus). Detect the point to do. Since α (T) corresponds to the first derivative of the time series data of Y (T), the point where the polarity of α (T) changes from positive to negative is the point where Y (T) becomes the maximum value. Corresponds to (maximum point). Although step 500 is repeatedly executed, α (T) newly calculated after the previous step 500 is executed is targeted for processing, and α (T) that has already been processed is not targeted for processing. The degree to which the point at which the polarity of α (T) changes from positive to negative coincides with the maximum point of Y (T) depends on the value of K, but it should be close to some extent for risk detection. Just do it.

Multiple maxima can be detected. The maximum point may not be detected. The control unit 208 keeps only the latest (largest elapsed time) maximum point including the detected maximum point and the maximum point already stored in the storage unit 110. That is, when one or a plurality of maximum points are detected, if the information for specifying the maximum point (for example, elapsed time) is stored in the storage unit 110, it is deleted and the information for specifying the latest maximum point is specified. Is stored in the storage unit 110. If the maximum point is not detected and the information for identifying the maximum point is stored in the storage unit 110, the information is kept stored in the storage unit 110.

In step 502, the control unit 208 determines whether or not a maximum point exists. Specifically, the control unit 108 determines whether or not the storage unit 110 stores information for specifying the maximum point. If it is stored, it is determined that there is a maximum point, and the control shifts to step 504. Otherwise, control returns to the flowchart of FIG. 10 and proceeds to step 418.

In step 504, the control unit 208 determines whether or not the polarity of α (T) is reversed in the predetermined observation period U (for example, 20 days) after the maximum point specified by step 502. Is determined. If it is determined that there is a polarity reversal, control proceeds to step 506. Otherwise, control shifts to step 508. If α (T) does not exist in a part of the observation period U after the maximum point (there is a period in which there is no measurement data and α (T) is not calculated), the polarity with respect to the calculated α (T). Judges the presence or absence of inversion of. If the polarity of α (T) is reversed after the maximum point, that point is the minimum point (the point where Y (T) becomes the maximum value). That is, it can be said that determining whether or not the polarity of α (T) is reversed in the observation period U after the maximum point determines the presence or absence of the minimum point.

In step 506, the control unit 208 deletes the information for specifying the maximum point stored in the storage unit 110. After that, control shifts to step 418 (FIG. 10).

In step 508, the control unit 208 determines whether or not the observation period U after the maximum point has elapsed. If it is determined that the elapse has passed, the control shifts to step 510. Otherwise, control proceeds to step 418 (FIG. 10).

In step 510, the control unit 208 determines the maximum point stored in the storage unit 110 as a risk point, and stores information indicating the determination in the storage unit 110. For example, the control unit 208 sets a predetermined flag (hereinafter, referred to as a risk flag) provided in the storage unit 110 to a value different from the initial value. After that, control shifts to step 418 (FIG. 10). The risk point means the time when there is a high possibility that a defect will occur in the printed circuit board due to corrosion due to hydrogen sulfide, and as described above, the time when the hydrogen sulfide concentration / days product becomes about 10,000 (ppb / day). It means (elapsed time). A risk point (maximum point) can be said to be a sign that a defect is likely to occur.

Returning to FIG. 10, in step 418, the control unit 208 determines whether or not a risk point has been detected. Specifically, the control unit 208 determines whether or not a value different from the initial value is set for the risk flag. If the risk flag has a value different from the initial value, it is determined that the risk point has been detected, and the control shifts to step 420. Otherwise, control proceeds to step 422.

In step 420, the control unit 208 reads a predetermined message from the storage unit 110 and presents it. As described above, when a risk point is detected, the pattern of the printed circuit board is corroded, and there is a high possibility that a defect will occur in the printed circuit board. Therefore, for example, it is presented that there is a high possibility that a defect will occur in the printed circuit board in the electric device. Further, the day when the risk point occurs may be specified from the information (elapsed time) for specifying the maximum point (risk point) stored in the storage unit 110, and that day may be presented together with the message. If the defect risk detecting device 200 includes an acoustic output device or an image display device, the message can be presented as an acoustic or an image. Data representing a message to be presented may be output from the defect risk detection device 200 to an external acoustic output device or image display device.

In step 422, the control unit 208 determines whether or not the end instruction has been received. If you are instructed to end, this program will end. If not, control returns to step 400 and repeats the above process. The end instruction is given, for example, by an operation of turning off the power of the failure risk detection device 200.

As described above, the risk of failure in the printed circuit board in the electric device can be automatically detected without calculating the hydrogen sulfide concentration in the surrounding environment in which the electric device is arranged. That is, the maximum point that occurs when the hydrogen sulfide concentration / day product reaches about 10,000 ppb / day, that is, the sign of failure risk can be automatically constantly monitored, and even if the hydrogen sulfide concentration changes, the sign of failure risk can be detected. It can be detected accurately. By detecting the failure risk sign, it is possible to take countermeasures before the performance deterioration, failure, etc. of the electric device occur, and the electric device can be appropriately managed.

The defect risk detection device 200 has a relatively simple device configuration and can be realized as an inexpensive device. By silver-plating the L-shaped member 116, the light reflecting portion 114 can be realized easily and inexpensively.

By observing the corrosion of silver Ag as a change in the reflectance of light (change in the generated voltage), it is possible to accurately detect a sign of a defect risk due to hydrogen sulfide. Since the measurement result (generated voltage) is an electric signal, remote monitoring is easily possible.

In the above, the case of storing the calculated time series data of α (T) has been described, but the present invention is not limited to this. Since the detection of the maximum point and whether or not the maximum point is a risk point are determined only by the polarity (signature) of α (T), at least the time series data of the polarity of α (T) is stored. Just leave it.

The above-mentioned values of the coefficients L and K and the observation period U are examples, and are not limited to the above-mentioned values. K (day) may be a real number between 5 and 20. As described above, since it is only necessary to know the polarity of α (T), the coefficient L may be any constant (real number) other than 0. When a negative value is used as the coefficient L, positive and negative may be exchanged in the polarity determination in the risk determination process. The observation period U is not limited to the above-mentioned value (20 days). The observation period U may be a value of 20 days or more and 30 days or less.

The first to fourth modifications described above with respect to the first embodiment are also possible in the second embodiment.

The experimental results regarding the first embodiment are shown below, and the effectiveness of the present invention is shown. Measurements were performed in three different environments using a hydrogen sulfide concentration estimation device (see FIG. 1) that adopted the photodetection system having the circuit configuration shown in FIG.

The configuration shown in FIG. 5 (third modification) was adopted for the photodetection system. A plurality of silver-plated flat plates to be placed on the L-shaped member were produced. The silver plating was hard / glossy silver plating and formed to a thickness of 3 μm. The purity of silver is about 99%. Since it is hard silver-plated, it contains a small amount of additives in addition to silver. As a light source, a red LED having a center wavelength of 630 nm was used. A variable resistor was used as the resistance R1 in the circuit of the photodetector system. In each environment, before starting the experiment, as described above, the measured value of the generated voltage (value after AD conversion) is about "130" (error) using the silver-plated plate in the initial state (corrosion-free state). The value of the resistor R1 was adjusted so as to be ± 3).

The results of hourly measurements from November 19 to the end of March of the following year are shown in FIGS. 12 (a) to 12 (c). 12 (a) to 12 (c) show measurement data in an environment where the hydrogen sulfide concentration is about 200 ppb (high concentration), about 15 ppb (low concentration) and about 1 ppb (nearly zero concentration), respectively. As described above, the measurement data shown is obtained by removing singular points from the time-series data of the measured values by using the moving median values of 25 consecutive data. The hydrogen sulfide concentration in each environment was measured using Ecochecker II. In each graph, the vertical axis is the generated voltage (relative value), the horizontal axis is the measurement date (month / day display with the year omitted), and corresponds to the elapsed time (day).

For the measurement data (generated voltage (relative value)) of each environment, the concentration / day product S is obtained as described above, and the measurement data is plotted with the concentration / day product S (ppb / day) as the horizontal axis, and is shown in FIG. The graph shown is generated. The graphs (a) to (c) of FIG. 13 were generated from the measurement data shown in FIGS. 12 (a) to 12 (c), respectively. The number of days used to calculate the concentration / number of days product S is the number of days elapsed from the start of measurement. The hydrogen sulfide concentration used for calculating the concentration / day product S was measured using Ecochecker II as described above. Specifically, Eco-Checker II is installed in each environment and replaced approximately every month, and the recovered Eco-Checker II is requested to be analyzed by Fujitsu Quality Lab Co., Ltd. to obtain the hydrogen sulfide concentration (reference concentration). rice field. The obtained hydrogen sulfide concentration can be said to be the average concentration of hydrogen sulfide during the period in which the eco-checker II was installed. Therefore, in the concentration / day product S, the hydrogen sulfide concentration (reference concentration) obtained from each eco-checker II was used as the hydrogen sulfide concentration during the period in which the eco-checker II was installed.

In each of FIGS. 13A to 13C, the generated voltage is Y, and the straight line of the following equation 3 is shown by a broken line.
Y = 130-0.075S ... (Equation 3)
From (a) to (c) of FIG. 13, it can be seen that the straight line of the broken line can almost reproduce the measurement data in the range of the concentration / day product S of 0 to about 1300 ppb / day. That is, as described above, in the range where the concentration / day product S is relatively small (S ≦ 1300 (ppb / day)), the generated voltage Y changes linearly with respect to the concentration / day product S and its slope. Was confirmed to be independent of hydrogen sulfide concentration.

Therefore, it can be seen that the hydrogen sulfide concentration can be estimated by the above equation 1. Since the concentration / day product S is the product (C × T) of the hydrogen sulfide concentration C and the number of days T, the generated voltage at each of T = T1 and T = T1 + ΔT is expressed by Y1 and Y1 + ΔY from Equation 3 to the following. 2 equations are obtained.
Y1 = 130-0.075 × (C × T1)
Y1 + ΔY = 130-0.075 × (C × (T1 + ΔT))
Therefore, ΔY = −0.075 × (C × ΔT), and when this is transformed,
C = − (ΔY / ΔT) /0.075.
Here, when the slope of a straight line 0.075 is expressed by L, the above equation 1 is obtained.

14 (a) to 14 (c) show the results of calculating the hydrogen sulfide concentration C using the above formula 1 with respect to the measurement data (generated voltage (relative value)) of each environment. The graphs (a) to (c) of FIG. 14 were generated from the measurement data shown in FIGS. 12 (a) to 12 (c), respectively. In Equation 1, L = 0.075. For K, different values were used so that the concentration / day product S did not exceed 1300 ppb / day. Specifically, K = 3 (day) for the measurement data (high concentration) shown in FIG. 12 (a), and K for the measurement data shown in FIGS. 12 (b) and (c). = 10 (Sun).

As described above, the measurement starts on November 19, but in (a) of FIG. 14, it takes 1 day to remove the singular point and 3 days (K = 3) to estimate the concentration. Therefore, the calculated values from November 13th are shown. From (a) of FIG. 14, the estimated value of hydrogen sulfide concentration reflecting the measurement results for 7 days from November 19 to November 26 is about 250 to 360 ppb. On the other hand, the average value of hydrogen sulfide concentration for one month from November 19 to December 20 by Ecochecker II was 200 ppb. The difference between these values is considered to be due to the difference in the measurement period, and it can be seen that the hydrogen sulfide concentration can be roughly estimated.

Further, in (b) and (c) of FIG. 14, since it takes 1 day to remove the singular point and 10 days (K = 10) to estimate the concentration, the calculated value from November 30 is required. It is shown. From (b) of FIG. 14, it can be seen that the estimated value of the hydrogen sulfide concentration is 9 to 18 ppb. From (c) of FIG. 14, it can be seen that the estimated value of the hydrogen sulfide concentration is 0 to 2 ppb. Therefore, both are almost the same as the hydrogen sulfide concentration by Ecochecker II (about 15 ppb and about 1 ppb, respectively). Therefore, it was confirmed that the hydrogen sulfide concentration in the environment can be accurately estimated regardless of the hydrogen sulfide concentration by measuring the generated voltage for a period of about 2 weeks using the hydrogen sulfide concentration estimation device.

The experimental results regarding the second embodiment are shown below, and the effectiveness of the present invention is shown. FIG. 15 was measured in a high concentration (50 to 200 ppb) hydrogen sulfide environment using a hydrogen sulfide defect risk detection device (see FIG. 8) that adopted the optical detection system having the circuit configuration shown in FIG. The result is shown.

The configuration shown in FIG. 5 (third modification) was adopted for the photodetection system. A silver-plated flat plate to be placed on the L-shaped member was produced in the same manner as in Example 1. As a light source, a red LED having a center wavelength of 630 nm was used. A variable resistor was used as the resistance R1 in the circuit of the photodetector system. In each environment, before starting the experiment, as described above, the measured value of the generated voltage (value after AD conversion) is about "130" (error) using the silver-plated plate in the initial state (corrosion-free state). The value of the resistor R1 was adjusted so as to be ± 3).

Measurements were taken hourly from November 19th to the end of March of the following year. The measured data shown is the time-series data of the measured values with the singularity removed using the median movement of 25 consecutive data. The hydrogen sulfide concentration in the environment was measured using Ecochecker II. The vertical axis is the generated voltage (relative value), and the horizontal axis is the measurement date (month / day display with the year omitted), which corresponds to the elapsed time (day).

In the measurement data (generated voltage) shown in FIG. 15, there are two maximum points (referred to as maximum points A and B, respectively) as indicated by arrows with reference numerals A and B.

With respect to the measurement data shown in FIG. 15, the concentration / day product S was obtained as described above, and the measurement data was plotted with the concentration / day product S (ppb / day) as the horizontal axis to generate the graph shown in FIG. The number of days used to calculate the concentration / number of days product S is the number of days elapsed from the start of measurement. The hydrogen sulfide concentration used for calculating the concentration / day product S was measured using Ecochecker II as described above. Specifically, Eco-Checker II is installed in each environment and replaced approximately every month, and the recovered Eco-Checker II is requested to be analyzed by Fujitsu Quality Lab Co., Ltd. to obtain the hydrogen sulfide concentration (reference concentration). rice field. In the concentration / day product S, the hydrogen sulfide concentration (reference concentration) obtained from each eco-checker II was defined as the hydrogen sulfide concentration during the period in which the eco-checker II was installed.

In FIG. 16, the points corresponding to the maximum points A and B in FIG. 15 are indicated by the same reference numerals A and B. In FIG. 16, a point indicated by reference numeral B exists shortly before the concentration / day product S becomes about 10,000 ppb / day. Therefore, it can be seen that if the maximum point B in FIG. 15 is detected, the time when the concentration / day product reaches about 10,000 ppb / day can be detected, and the risk of malfunction due to hydrogen sulfide in the printed circuit board can be detected. It is considered that this phenomenon is caused by the change in the color of silver (silver sulfide) from silver to brown to blue to black as the corrosion of silver progresses. That is, the phenomenon that the color fades in the process of changing to blue is observed, the reflectance of the synchrotron radiation of the red LED temporarily increases (the generated voltage increases), and then the color changes to black, so that the reflectance Continues to decrease for a predetermined period (20 to 30 days) or longer (generated voltage decreases).

In FIG. 15, since the maximum point A exists before the maximum point B, the first maximum point A is detected by a process of simply detecting the maximum point. On the other hand, the maximum point A can be excluded and the maximum point B can be detected by the risk determination process shown in FIG. That is, in step 500 of FIG. 11, the maximum point A is detected first after the start of measurement, but in steps 504 to 508, the maximum point A is excluded and the maximum point B is detected. It will be specifically shown with reference to FIG.

FIG. 17 shows the slope α of the generated voltage calculated by the above equation 2 with K = 10 and L = 0.075 for the measurement data shown in FIG. In FIG. 17, since it takes 1 day to remove the singular point and 10 days (K = 10) to calculate the slope α, the calculated value from November 30 is shown. In addition, in FIG. 17, there is a part where the graph is not continuous (a part where the slope is not shown) between December 1st and December 21st of the measurement date, but this is because the slope between them is-. This is because it is less than 20 or more than 20.

In FIG. 17, the positions (measurement dates) of the maximum points A and B in FIG. 15 are indicated by reference numerals A and B. At the maximum point, the slope of the tangent is 0, and the sign (polarity) of the slope of the tangent changes before and after that, but the slope α shown in FIG. 17 approximates the tangent and is 10 days (K =). 10) It is calculated by Equation 2 as described above using the difference ΔY between the two measurement data at intervals. As for the maximum point A shown in FIG. 15, the measurement data changes significantly before and after the maximum point A. Therefore, in FIG. 17, the point on the horizontal axis (measurement date) indicated by the arrow with the reference numeral C (hereinafter referred to as the point). It appears as (C). On the other hand, the maximum point B shown in FIG. 15 is the maximum point of the comparatively gently changing portion, and also appears at substantially the same position in FIG.

Since the slope α calculated by the equation 2 changes as shown in FIG. 17, the point C corresponding to the maximum point A is detected by the step 500 shown in FIG. 11 and stored in the storage unit 110. However, after that, since the polarity of the slope α changes from positive to negative within the observation period (20 days) (see reference numeral D), points C corresponding to the maximum point A are excluded by steps 504 and 506 (storage unit). Deleted from 110). Then, in step 500, the point corresponding to the maximum point B is detected, and thereafter, the polarity of the slope α does not change during the observation period (20 days). Therefore, in step 510, the maximum point B is determined as the risk point. That is, the time when the concentration / day product reaches about 10,000 ppb / day can be detected as a sign of failure risk.

The maximum point B is determined as a risk point when the observation period (for example, 20 days) has elapsed since the occurrence of the maximum point B. Meanwhile, the printed circuit board is corroded by hydrogen sulfide. However, since the maximum point B occurs around the time when the concentration / day product S = 10000 ppb / day, there is a high possibility that the concentration / day product S will have a problem within the observation period from the maximum point B. It will never be more than about 15,000 ppb / day.

Although the present invention has been described above by explaining the embodiments, the above-described embodiments are examples, and the present invention is not limited to the above-described embodiments. The scope of the present invention is indicated by each claim of the scope of claims, taking into consideration the description of the detailed description of the invention, and all changes within the meaning and scope equivalent to the wording described therein are made. include.

100 Hydrogen sulfide concentration estimation device 102, 202 Light emitting unit 104 Power supply unit 106, 206 Photodetecting unit 108, 208 Control unit 110 Storage unit 112 Timer 114, 118 Light reflecting unit 116 L-shaped member 120, 122 Surface 124 Silver-plated plate 126 Flat plate 130, 230 LED
132, 232 Phototransistor 134 Measurement terminal 140, 142, 144, 146 Terminal 200 Defect risk detector 900 Printed circuit board Ag Silver R1, R2, R3 Resistance

Claims (5)

Reflectors with silver on the surface and
A light emitting means for irradiating the silver arranged on the surface of the reflecting portion with light,
A photodetecting means for detecting the light reflected by the silver arranged on the surface of the reflecting portion, and
A measurement terminal that generates a voltage corresponding to a current flowing through the photodetecting means in a state where the silver arranged on the surface of the reflecting portion is irradiated with light from the light emitting means.
A measuring means for measuring the voltage of the measuring terminal and
A hydrogen sulfide concentration estimation device comprising a calculation means for calculating an estimated value of hydrogen sulfide concentration in the surrounding environment of the reflection unit based on the voltage measured by the measuring means. In the first time-series data composed of the voltage repeatedly measured by the measuring means in a predetermined period, the first voltage was measured from one first voltage K days before the first voltage was measured. The difference obtained by subtracting the two voltages is ΔY, the constant is L, the estimated value is C, and the calculation means calculates the estimated value by C = − (ΔY / K) / L.
The L is a value representing the magnitude of the slope when the graph obtained by plotting the measurement data of the voltage against the product of the hydrogen sulfide concentration at the time of measuring the voltage and the number of days elapsed from the start of the measurement is linearly approximated. The hydrogen sulfide concentration estimation device according to claim 1, wherein the device is characterized by the above. The voltage measurement interval is 1 minute or more and 1 hour or less.
The calculation means replaces the second time-series data composed of the moving median determined from the first time-series data with the first time-series data, and calculates the estimated value.
The median movement is the median value when the data in the first time-series data for a continuous period of 12 hours or more and 2 days or less are arranged in order of size, according to claim 2. Hydrogen sulfide concentration estimation device. Reflectors with silver on the surface and
A light emitting means for irradiating the silver arranged on the surface of the reflecting portion with light,
A photodetecting means for detecting the light reflected by the silver arranged on the surface of the reflecting portion, and
A measurement terminal that generates a voltage corresponding to a current flowing through the photodetecting means in a state where the silver arranged on the surface of the reflecting portion is irradiated with light from the light emitting means.
A measuring means for measuring the voltage of the measuring terminal and
A defect risk, which comprises a detection means for detecting a risk of a defect due to corrosion due to hydrogen sulfide in a printed circuit board arranged around the reflective portion based on the voltage measured by the measuring means. Detection device. The detection means
The maximum point in the time series data composed of the voltage measured by the measuring means in a predetermined period is detected.
After the maximum point, it is determined whether or not the minimum point exists within a predetermined observation period, and the minimum point is determined.
In response to the determination that the minimum point does not exist within the observation period, it is determined that the risk has been detected.
The defect risk detecting device according to claim 4, wherein the observation period is 20 days or more and 30 days or less.

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