JPH04218755A - Apparatus for diagnosing deterioration of film - Google Patents

Abstract

PURPOSE:To miniaturize an apparatus as a whole in an apparatus diagnosing the deterioration degree of a film on the basis of the measured result of the impedance of the film. CONSTITUTION:The I/F board 18 provided in the expansion slot of a personal computer 11 applies voltage having a predetermined waveform across the probe 20 applied to the surface of a film 19 and a substrate metal 21. A preamplifier 22 measures the current flowing to the probe 20. The spectrum data of the preliminarily calculated output voltage waveform from the I/F board 18 is stored in a memory 13 and a CPU 12 calculates the impedance Z of the film from a measured current value (i) and the stored voltage value E.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint film deterioration diagnosing device for objectively determining the degree of deterioration of a paint film.

0003

[Prior Art] Equipment placed outdoors, such as transformers and switchboards, is painted for corrosion protection and aesthetic purposes.
The coating deteriorates over time due to the effects of UV rays and moisture. If such deterioration of the paint film is left untreated, the paint film will eventually peel off or the underlying metal will corrode, which may lead to equipment malfunction. Therefore, in order to perform repainting and maintenance at appropriate times, the degree of deterioration of the paint film is quantitatively evaluated by measuring the paint film impedance.

In this case, the coating film impedance can be expressed by an equivalent circuit consisting of a parallel circuit of a resistor R and a capacitor C as shown in FIG. 4, and as the coating film deteriorates, the resistance R value increases. The degree of deterioration of the paint film can be diagnosed by utilizing the fact that the impedance changes as the impedance decreases.

[0005] As an apparatus for measuring the impedance of such a coating film, there is disclosed a method disclosed in Japanese Patent Laid-Open No. 1986-10 filed by the present applicant.
There is one shown in Publication No. 2148. As shown in FIG. 9, a probe 3 is applied to a coating film 2 on a base metal 1, and an AC power source is connected between the probe 3 and the base metal 1.
The current measuring device 5 measures the flowing current i, and the voltage measuring device 6 measures the applied voltage e between the probe 3 and the base metal 1. The measured current value i and voltage value e are input to the transfer function meter 7, and the transfer function meter 7 calculates and outputs the impedance Z for each frequency.

[0006]

By the way, in order to measure the coating film impedance as described above, it is necessary to transport the measuring device to the site where the transformer and the like are installed. For this reason, it is desired that the coating film impedance measuring device as described above be lightweight and compact.

On the other hand, in the conventional coating film impedance measuring device described above, in order to measure the coating film impedance, it is necessary to measure the current and voltage each time. 6 vessels were required. For this reason, the entire device becomes relatively large, and there is a limit to how much it can be made lighter and smaller.

The present invention has been made in view of the above circumstances, and its object is to provide a coating film deterioration diagnosing device that can effectively downsize the entire device.

[Configuration of the invention]

0010

[Means for Solving the Problems] The paint film deterioration diagnosing device of the present invention includes a probe that is applied to the surface of a paint film, and a voltage that applies a voltage of a predetermined waveform between the base metal of the paint film and the probe. The present invention is characterized in that it includes an applying means and a current measuring means for measuring the current flowing through the coating film to the probe in order to determine the degree of deterioration of the coating film.

[0011]

[Operation] When a voltage is applied between the base metal and the probe by the voltage applying means, a current flows through the coating through the probe and is measured by the current measuring means. It is known that the impedance of the paint film has a correlation with the degree of deterioration of the paint film, so the degree of deterioration of the paint film can be diagnosed using a predetermined analysis procedure that takes into consideration the impedance measurement frequency and the above correlation. can do.

[0012] Here, calculation of impedance requires the voltage applied to the coating film and the current flowing through the coating film, but since the voltage application means applies a voltage with a predetermined waveform, By making the applied voltage at the time of membrane impedance measurement have the same waveform each time, it is possible to eliminate the need to measure the applied voltage each time.

[0013] Therefore, it is now possible to detect the coating film impedance by measuring only the current using the current measuring means, and as a result, it is possible to eliminate the need for a device for measuring voltage, and the overall size of the device can be reduced. can be achieved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. Reference numeral 11 designates a so-called laptop-type or book-type personal computer, which includes a CPU 12, a memory 13, an FDD (floppy disk drive) 14, an HDD (hard disk drive) 15, etc. in a main body case (not shown). In addition, it has a general configuration including a liquid crystal display 16 and a keyboard 17. In the expansion slot of this personal computer 11, a D/A
I/F board 18 with conversion function and A/D conversion function
is inserted.

On the other hand, a probe 20 is applied to the surface of the coating film 19 on which deterioration diagnosis is to be performed. This probe 20
Although various structures are known (for example, Japanese Patent Application Laid-Open No. 108954/1983), detailed illustrations are not provided, but basically a sponge-like electrode in which a conductive gel is soaked into the main body container is used. In addition to being stored, the main container is equipped with a permanent magnet around the opening, and the sponge-like electrode is applied to the coating film 19 by the attractive force that acts between the permanent magnet and the base metal 21.
It is designed to adhere to the surface of the

A lead wire led out from the probe 20;
The lead wire connected to the base metal is connected to the preamplifier 22. This preamplifier 22 is composed of a current-voltage conversion resistor 23 (resistance value R) and a programmable gain amplifier 24 that amplifies the voltage generated across the resistor.
A voltage signal corresponding to the current value i flowing through the coating film 19 is applied to the I/F board 18 of the personal computer 11. In this way, the preamplifier 22 functions as a current measuring means for measuring the current flowing to the probe 20 through the coating film 19.

The preamplifier 22 is capable of changing the measurement range depending on the degree of deterioration of the coating film 19, and in this embodiment, the resistance value R of the current-voltage conversion resistor 23 is
is 100Ω to 1MΩ, and the amplifier amplification G is 10 to 100
At 0x, it is possible to measure a measurement current in the range of 1 pA to 1 mA (10 KΩ to 10 GΩ or more as coating film resistance).

Now, the I/F board 18 has a probe 20
The I/F board 18 functions as a voltage applying means for applying a voltage of a predetermined waveform between the I/F board 18 and the base metal 21 based on digital information stored in advance in the floppy disk
It outputs a voltage with a predetermined waveform generated and synthesized by the D/A conversion function. In this embodiment, the predetermined voltage waveform to be applied is 0.1Hz to 50Hz (0.1Hz to 50Hz).
500 points at 1Hz intervals), and the power spectrum P is

[0019]

[Math 1]

From [0020]

[0021]

[Math 2]

It is made to exist between [0022]. FIG. 3 shows an example of voltage waveforms synthesized so that the power spectrum P becomes P=1/f. Further, here, the phase of each frequency component constituting this voltage waveform is randomized to suppress the peak voltage as much as possible.

[0023] Furthermore, the D/A conversion and A
The timing with /D conversion is configured to be the same every time, so that the phase angle of the applied voltage and the current measurement phase angle of the preamplifier 22 are kept the same. . Furthermore, as will be described later, the memory 13 of the personal computer 11 has a predetermined I/F
Spectral data of the output voltage waveform from the board 18 is stored.

Next, a procedure for diagnosing the coating film 19 using the coating film deterioration diagnosing apparatus having the above configuration will be explained. This should clarify the functions performed by the personal computer 11.

First, as a preparatory step before actually diagnosing the coating film 19, the output voltage value E from the I/F board 18 is
It is done to find out. This is shown in Figure 2.
A calibration resistor 25 (instead of the coating 19) is attached to the measurement terminal of the measuring device.
This is done by connecting the resistance value Ra), applying a predetermined voltage, and measuring the flowing current value i using the preamplifier 22, as in the case of coating film impedance measurement. At this time,
The value of the current i is determined from the preamplifier 22 to the I/F board 18.
The signal is input to the CPU 12 through the A/D conversion function. C
PU12 is FFT (fast Fourier transform) using machine language.
A voltage value E is calculated from the following equation (1) using a program or the like, and the result (spectral data) is stored in the memory 13.

E=i(Ra+R)
...(1) Here, as shown in FIG. 1, in order to measure the impedance Z of the coating film 19, the voltage value e applied to the coating film 19 and the flowing current value i are required. , the voltage value e is the voltage value generated in the current-voltage conversion resistor 23 by Δ
If e(Δe=iR), then e=E−Δe...
(2) becomes. However, since the voltage value E has a predetermined waveform, as described above, by determining the voltage value E using the calibration resistor 25, it is no longer necessary to measure the voltage value e each time the coating film impedance is measured. It will disappear. In addition, if the current-voltage conversion resistor 23 is used whose resistance value R is sufficiently smaller than the coating film impedance Z, the above (
2) The formula is e=E
...Approximated as (3), FFT with narrow measurement frequency range
In practical impedance measurement using equation (3), sufficient accuracy can be obtained. In addition, in this case, the above equation (1) also has E=iRa
...It can be rewritten as shown in (4).

Next, the procedure for diagnosing paint film deterioration will be described. A personal computer 11 is installed at the site where deterioration diagnosis is performed.
The preamplifier 22 and probe 20 are brought in, and the probe 20 is connected to the surface of the coating film 19 together with the preamplifier 22 as shown in FIG. Then, the measurement program stored in the FDD 14 or HDD 15 is executed.

As a result of executing this program, probe 2
0 and the base metal 21, the current flowing through the coating film 19 at that time is detected by the preamplifier 22, and a voltage signal corresponding to the current is given to the I/F board 18 of the personal computer 11. , the voltage signal is converted into a digital signal by the A/D conversion function of the I/F board 18. Then, the CPU 12 selects the measured current value i and the voltage value E which has been determined and stored in advance using equation (1).
Then, the coating film impedance Z is calculated using the following equation (5), and the result is written to an external storage device such as the FDD 14 or the HDD 15.

Z=E/i-R
...(5) In this case, the coating film impedance Z is
It can be expressed as an equivalent circuit consisting of a parallel circuit of a resistor R and a capacitor C as shown in FIG. Thus, the degree of deterioration of the coating film 19 can be diagnosed.

Such measurement of the coating film impedance Z is carried out at a plurality of locations on the coating film 9, and in addition to this measurement, from the keyboard 17 of the personal computer 11,
Measurement data such as the type of coating film 19 (equipment), the thickness of the coating film 19, and the area of the probe 20 at the time of measurement are input, and are also recorded in an external storage device such as the FDD 14 or HDD 15 at the same time.

After the measurement using the probe 20 as described above is completed, the diagnostic program is then read from the floppy disk and executed. The execution procedure of this diagnostic program is as shown in the flowchart of FIG.

Step S1: Reading measurement data First, the measurement data recorded in the floppy disk is read out, and the thickness of the coating film 19, the area of the probe 20, etc. at the time of measurement are displayed on the display 16 for confirmation. Ru. After this, when a confirmation operation is performed, the display 16 becomes an initial condition input screen.

Step S2: Input of initial conditions Here, codes representing the type of paint, age of use, external appearance, installation environment, etc. for diagnosing the deterioration state of the paint film are input from the keyboard 17.

Step S3: Smoothing The impedance measurement data is smoothed. This is because impedance data measured on site may not necessarily change uniformly with respect to each frequency, so measurement accuracy is improved by smoothing the data.

Step S4: Data Analysis First, the coating film impedance Z1 at 0.1 Hz is determined based on the smoothed impedance data, and for confirmation, a graph of the coating film impedance Z1 and Cx (capacitance component) for each frequency f is drawn. Create/display.

Step S5: Repetition of analysis and discrimination of incorrect data Since the coating film impedance Z1 is measured at multiple locations for one device, the above data analysis is repeated as many times as the number of measurement locations, and the data analysis at each measurement point is repeated. Calculate the average value and variance of the coating film impedance Z1 at 0.1 Hz,
Exclude abnormal data as erroneous data due to measurement errors, etc.

Step S6: Creating a life estimation diagram The logarithm logZ of the coating film impedance Z has a linear relationship with time t. Further, the initial impedance Z0 corresponding to the paint type input in step S2 is stored as known data, and the number of years of use is input in step S2. Therefore, from this information, the logarithm logZ0 of the initial impedance Z0 and the measured coating film impedance Z1 are calculated as shown in FIG.
By connecting the logarithm of logZ1 with a straight line L,
You can draw a lifespan estimation diagram. Here, the remaining life tr refers to the time from the measurement time t1 to the point where the extension of the straight line L intersects the life line R. In addition, the life line R is determined in advance based on the degree of deterioration of the paint film, the degree of rusting of the base metal, and the paint film impedance Z at that time by conducting an exposure test or accelerated test of the paint film in advance. be able to. Note that in the life estimation diagram, the time axis may be represented by the square of t, as shown in FIG. 7, in consideration of estimation accuracy.

Step S7: Prediction of degree of deterioration and repainting time The degree of deterioration is ranked based on the range of the detected value of the coating film impedance Z1. Here, it is divided into three stages A, B, and C, and the display 16
For example, a display as shown in FIG. 8 is displayed.

Step S8: Estimation of Deterioration Factors After this, when the deterioration factor estimation program is activated, expert reasoning is executed in an interactive manner, and the deterioration factors are estimated based on the measurement results of the coating film impedance Z1. , the results are displayed on the display 16. Further, the results and graphs during analysis can also be output to a printer 26.

As described above, in this embodiment, the CPU 12 operating according to the above-mentioned diagnostic program performs analysis work based on the data of the coating film impedance Z to judge the degree of deterioration of the coating film, and the display 16 displays the judgment result. It is now displayed. As a result, it is possible to always make appropriate judgments about the degree of deterioration of the paint film, regardless of who is performing the operation.
Moreover, the work can be done easily and accurately.

Since the I/F board 18 is configured to output a voltage with a predetermined waveform, the applied voltage can be measured each time by making the applied voltage the same waveform each time when measuring the coating film impedance. I was able to make that unnecessary. Therefore, unlike the conventional device which is equipped with both a current measuring device 5 and a voltage measuring device 6, it is now possible to detect the coating film impedance Z by measuring only the current value i, and as a result, A device for measuring voltage can be made unnecessary, and the entire device can be made more compact.

In the above embodiment, one personal computer 11 not only measures the coating film impedance Z but also analyzes the data. However, the present invention can be modified in various ways without departing from the scope of the invention, for example, data analysis may be performed in a separate device using the floppy disk.

[0043]

Effects of the Invention As is clear from the above explanation, the paint film deterioration diagnosing device of the present invention uses a probe applied to the surface of a paint film, and a voltage of a predetermined waveform to be applied to the base metal of the paint film and the probe. and a current measuring means that measures the current flowing through the coating film to the probe in order to judge the degree of deterioration of the coating film. This eliminates the need for a device to measure the voltage each time the device is used, and has the excellent effect of effectively downsizing the entire device.

[Brief explanation of the drawing]

FIG. 1: Overall block diagram showing one embodiment of the present invention

[Figure 2] Overall block diagram showing the state when measuring applied voltage

[Figure 3] Waveform diagram showing an example of the voltage waveform applied to the coating film

[Figure 4] Equivalent circuit of coating film impedance

[Figure 5] Flowchart of diagnostic program

[Figure 6] Paint film life estimation diagram

[Figure 7] Different display examples of paint film life estimation diagrams

[Figure 8] Diagram showing an example of displaying diagnostic results

[Fig. 9] Block diagram of a device showing a conventional example

[Explanation of symbols]

11 is a personal computer, 12 is a CPU, 16 is a display, 18 is an I/F board (voltage application means),
19 is a coating film, 20 is a probe, 21 is a base metal, and 22 is a preamplifier (current measuring means).

Claims (1)

[Claims] 1. A probe that is applied to the surface of a paint film, voltage application means that applies a voltage of a predetermined waveform between the base metal of the paint film and the probe, and a method for determining the degree of deterioration of the paint film. and current measuring means for measuring the current flowing to the probe through the coating film.