JP7202827B2 - Paint film diagnosis device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating film diagnostic apparatus for diagnosing a coating film.

Coating films formed on structures such as bridges and plants deteriorate over time due to exposure to rainwater and direct sunlight. In addition, with this aged deterioration, problems such as corrosion of the base metal of the structure and generation of rust, peeling of the coating film, and the like occur. In order to prevent such problems from occurring, it is necessary for a structure manager, etc., to periodically diagnose the state of the coating film on the structure on-site, and repair or repaint based on the diagnosis results. It is necessary to properly determine whether or not there is

However, such a diagnosis of the state of the coating film is not easy, and even an expert may make an error in the diagnosis. Therefore, a coating film diagnostic apparatus for objectively diagnosing a coating film has been used. An example of the coating film diagnostic apparatus is described in Patent Document 1 and Patent Document 2.

In the technique disclosed in Patent Document 1, when diagnosing a corrosive environment, a variable resistance is changed so that the current flowing in the corrosive environment maintains a substantially constant value (for example, 100 [nA]). Diagnose your environment. Further, in the technique disclosed in Patent Document 2, a constant current circuit whose range can be switched by a plurality of resistors is used to diagnose corrosion under the paint film.

Japanese Unexamined Patent Application Publication No. 2011-137760 JP-A-4-172241

By using the diagnosis apparatus disclosed in Patent Document 1, Patent Document 2, etc., it is possible to objectively judge the state of the coating film.
However, these diagnostic devices require a large number of resistors for range switching, a relay circuit for switching the resistors, and the like, in order to flow a constant current. Therefore, it is difficult to simplify the configuration of the diagnostic device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating film diagnostic apparatus having a simpler configuration than the conventional one.

The objects of the invention have been achieved by:

The coating film diagnostic apparatus of the present invention includes a first electrode (for example, a first electrode 18 described later) arranged on the surface of a coating material forming a coating film on a substrate, and a predetermined electric signal to the first electrode. A second electrode (for example, a DAC 151 to be described later) arranged at a position where a current based on the predetermined electrical signal applied to the first electrode flows through the coating film and the substrate (for example, a DAC 151 to be described later). second electrode 19), conversion means (for example, a current log amp 152 described later) that outputs a voltage obtained by logarithmically converting the current flowing through the second electrode, and the voltage value of the voltage output by the conversion means, and a control means (for example, a CPU 111 to be described later) that acquires diagnostic information about the coating film.

According to the present invention, it is possible to provide a coating film diagnostic apparatus having a simpler configuration than the conventional one.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of the external structure of a coating film diagnosis device that is an embodiment of the present invention; FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; 1 is a block diagram showing an example of functional blocks of a coating film diagnostic apparatus that is an embodiment of the present invention; FIG. FIG. 10 is a graph showing an example of waveforms for explaining redoing the coating film diagnosis in the prior art; FIG. 4 is a graph showing an example of waveforms for explaining adjustment of a current value during coating film diagnosis in the embodiment of the present invention. FIG. 11 is a block diagram showing an example of functional blocks of a coating film diagnostic device in a modified example of the embodiment of the present invention; 7 is a graph showing a waveform example for explaining coating film diagnosis in a modified example of the embodiment of the present invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
<Appearance structure of coating film diagnosis device>
First, with reference to FIGS. 1 and 2, the external configuration of a coating film diagnosis apparatus 10 according to the present embodiment will be described. The coating film diagnosis device 10 has a substantially cylindrical shape. 1 is a top view of this substantially cylindrical coating film diagnostic apparatus 10, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.

As shown in FIG. 1, the coating film diagnostic apparatus 10 has a control board 11, an LCD (Liquid Crystal Display) display 12, a setting SW group 13, and a USB (Universal Serial Bus) connector 14 on the upper surface. In addition, in FIG. 1 , illustration of a housing that accommodates each part included in the coating film diagnostic apparatus 10 is omitted.

The control board 11 is a printed board on which a CPU (Central Processing Unit) and the like for controlling the coating film diagnostic apparatus 10 are mounted. Details of the CPU and the like mounted on the control board 11 will be described later with reference to FIG.

The LCD display 12 is a user interface for various settings related to coating film diagnosis, and a display for displaying diagnosis results calculated by arithmetic processing by the CPU.
The setting SW group 13 is a part that receives operations from the user to perform various settings related to coating film diagnosis. The setting SW group 13 is realized by, for example, a plurality of button switches.

The USB connector 14 is a connector for transmitting and receiving predetermined information between the CPU and an external device. The USB connector 14 is implemented by a connector conforming to the USB standard. For example, a personal computer is connected to the USB connector 14 as an external device.

In addition, as shown in FIG. 2 , the coating film diagnostic apparatus 10 further includes an analog board 15 , a battery 16 , a spacer 17 , a first electrode 18 , a second electrode 19 and a magnet section 20 . These components included in the coating film diagnostic apparatus 10 are housed in the housing 21 .

The analog substrate 15 is a substrate on which electronic components are mounted for realizing a constant current circuit for coating film diagnosis. Details of the electronic components mounted on the analog board 15 will be described later with reference to FIG.

The battery 16 is a battery for supplying electric power to each part of the coating film diagnostic device 10 . For example, the LCD display 12 and the electronic components mounted on the control board 11 and the analog board 15 are driven by power supplied from the battery 16 .

The spacer 17 is a portion that provides a predetermined space between the control board 11 and the analog board 15 . Electronic components mounted on the analog board 15 are arranged in this predetermined space.

The first electrode 18 is an electrode arranged on the substrate (for example, iron) of the structure on which the coating film to be diagnosed by the coating film diagnostic apparatus 10 is formed. Further, the second electrode 19 is an electrode arranged on the surface of the coating film in the structure on which the coating film to be diagnosed is formed.

The first electrode 18 is realized, for example, as a probe, which is a contact for placement on the substrate. On the other hand, the second electrode 19 is realized by, for example, an electrode to which a sponge-like pad impregnated with conductive gel is attached. However, the coating film diagnosis apparatus 10 can diagnose even when the resistance value of the object to be diagnosed is large compared to the conventional one. Therefore, such spongy pads impregnated with conductive gel can often be used for diagnosis without the need for increased conductivity. In such a case, the second electrode 19 may be realized by a dry electrode without a pad.

The magnet part 20 is a part provided with a permanent magnet. The second electrode 19 adheres to the paint on the surface of the coating film due to the attractive force acting between the magnet part 20 and the base of the structure on which the coating film to be diagnosed is formed.

The housing 21 is a housing that accommodates each part of the coating film diagnostic apparatus 10 . The housing 21 is made of, for example, ABS resin. The shape of the housing 21 is substantially cylindrical as described above, and its diameter is, for example, 5 [cm]. An opening is provided in the bottom surface of the housing 21, and the above-described second electrode 19 protrudes from the opening. The second electrode 19 also has a substantially cylindrical shape, and its diameter is, for example, 3.8 [cm]. Note that the structure of the housing 21 itself is not the gist of the present embodiment, so the illustration of the structure of the opening of the housing 21 is omitted.

<Functional blocks inside the paint film diagnosis device>
Next, functional blocks inside the coating film diagnostic apparatus 10 configured as described above will be described with reference to FIG.

The coating film diagnosis apparatus 10 includes a CPU 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, and a bus 114 as functional blocks. These units are implemented by electronic components mounted on the control board 11 .

In addition, the coating film diagnosis apparatus 10 includes, as functional blocks, a D/A conversion circuit (denoted as "DAC" in the drawing) 151, a current log amplifier (denoted as "logIVC" in the drawing) 152, and An A/D conversion circuit (denoted as “ADC” in the drawing) 153 is provided. These units are implemented by electronic components mounted on the analog board 15 .

In addition to these functional blocks, the bus 114 is also connected to the LCD display 12 , the setting SW group 13 , and the USB connector 14 . Furthermore, an external device 300 is connected to the USB connector 14 . Furthermore, the output terminal of the D/A conversion circuit 151 is connected to a lead wire led out from the first electrode 18 . A lead wire drawn out from the second electrode 19 is connected to an input terminal of the current log amplifier 152 .

Next, functions and operations of these units will be described.
The CPU 111 is a part that executes coating film diagnostic processing by controlling the coating film diagnostic apparatus 10 as a whole. The CPU 111 reads a program recorded in the ROM 112 , develops the read program in the RAM 113 , and performs arithmetic processing based on the program. Also, the CPU 111 controls various hardware provided in each device based on the calculation result. Thus, the functional blocks of the coating film diagnosis device 10 are realized. In other words, the coating film diagnostic device 10 can be realized by cooperation of hardware and software.

A bus 114 connects the CPU 111, the ROM 112, the RAM 113, the LCD display 12, the setting SW group 13, and the USB connector 14, and relays data transmitted and received between these units. As data to be transmitted and received, for example, image data to be displayed on the LCD display 12 is transmitted from the CPU 111 to the LCD display 12 . Also, for example, data indicating the operation content received by the setting SW group 13 is transmitted from the setting SW group 13 to the CPU 111 . Also, for example, measurement data, which will be described later, is transmitted from the CPU 111 to the external device 300 .

The D/A conversion circuit 151 generates a constant current by digital-analog conversion of control data input from the CPU 111 via the bus 114, and applies the generated constant current Is to the first electrode 18. is. The constant current Is applied by the D/A conversion circuit 151 is, for example, 1 [pA] to 1 [mA]. The current value of this constant current Is is appropriately set by the CPU 111 .

A current Is applied to the first electrode 18 flows to the second electrode 19 through the coating film and the substrate.
The current log amp 152 is a current log amp that inputs the current flowing through the second electrode and outputs a voltage Vs obtained by logarithmically compressing the input current. That is, the current log amp 152 logarithmically converts the output voltage Vs to a logarithmic function (log) with respect to the input current.

Here, the current log amp 152 can be input with a very wide range of current, for example, 1 [pA] to 1 [mA]. Therefore, in the coating film diagnostic device 10, unlike the conventional coating film diagnostic device using a log amp with a voltage input, it is not necessary to supply current only within a predetermined range by switching the range. Therefore, the coating film diagnosis apparatus 10 does not require many resistors for range switching, relay circuits for switching resistors, and the like.
That is, in this embodiment, it is possible to provide the coating film diagnostic device 10, which is a coating film diagnostic device with a simpler configuration than the conventional one.

The A/D conversion circuit 153 is a part that analog-digital converts the voltage Vs output from the current log amplifier 152 . The digital value after conversion by the A/D conversion circuit 153 (that is, the voltage value of the voltage Vs) is output to the CPU 111 as measurement data.

<Paint film diagnosis>
With the functions of the functional blocks described above, the diagnosis of the coating film by the coating film diagnostic device 10 can be realized.
Specifically, the CPU 111 generates control data based on this measurement data, thereby controlling the D/A conversion circuit 151 to output a constant current.
The CPU 111 also diagnoses the coating film based on this measurement data. Then, the CPU 111 causes the LCD display 12 to display the diagnosis result.

Alternatively, the CPU 111 transmits this measurement data to the external device 300 via the bus 114 and the USB connector 14 (and the USB cable connecting the USB connector 14 and the external device 300). Then, the external device 300 diagnoses the coating film based on the received measurement data, and displays the diagnosis result on the display.

Any method may be used for the coating film diagnosis performed by the CPU 111 or the external device 300 . For example, the CPU 111 and the external device 300 can diagnose the coating film using the current interrupter method. Here, the current interrupter method is a method certified by ISO 13129 (Paints and varnishes. Electrochemical measurement of the protection provided to steel by paint coatings. Current interrupter technique, relaxation voltammetry technique and DC transient measurements) in 2012, Since it is well known to those skilled in the art, further detailed description is omitted.

<Effects of the Coating Diagnosis Device 10>
The effects of the coating film diagnostic apparatus 10 described above will be described.
Since the conventional coating film diagnostic devices described in Patent Document 1 and Patent Document 2 described above use a log amp that inputs voltage, many resistors for range switching, relay circuits for switching resistors, etc. was necessary. For example, ten resistors ranging from 1 [kΩ] to 1 [TΩ] and a relay circuit or the like for switching these resistors were required.

On the other hand, since the coating film diagnostic apparatus 10 uses the current log amplifier 152, as described above, many resistors for switching ranges and relay circuits for switching resistors can be omitted. . That is, according to the present embodiment, it is possible to provide a coating film diagnostic device that is a coating film diagnostic device with a simpler configuration than the conventional one.

Along with this, it is also possible to reduce the size and weight of the coating film diagnostic apparatus. For example, the weight of the conventional paint film diagnostic apparatus is about 8 [kg], and the size is about 30 [cm]×30 [cm]×20 [cm]. On the other hand, according to the present embodiment, the coating film diagnostic apparatus can be realized with a simpler configuration. shape.

In addition, since the conventional coating film diagnostic apparatus has the weight and size as described above, it was not possible to perform a diagnosis by placing the apparatus directly on a structure to be diagnosed. Therefore, after installing the coating film diagnostic device at a position away from the structure, diagnosis is performed by connecting the coating film diagnostic device and the sensor unit (corresponding to the second electrode 19) by, for example, a coaxial cable. However, in this case, since the insulation resistance of the coaxial cable is, for example, 500 [MΩ], there is a problem that the accuracy is lowered when measuring high resistance. In addition, since an electric charge is generated when the coaxial cable shakes, it is difficult to make a diagnosis outdoors where there is vibration.

On the other hand, according to the present embodiment, the coating film diagnostic device 10 can be made lightweight and compact as described above. Can be placed and diagnosed. Therefore, according to this embodiment, it is possible to eliminate the inconvenience caused by the coaxial cable as in the prior art.

Further, in this embodiment, the current value of the constant current Is can be changed even during measurement. This point will be described with reference to FIGS. 4 and 5. FIG.
As a premise, when the voltage Vs obtained by multiplying the constant current Is by the resistance component of the coating film and base becomes a predetermined value or more (for example, 0.1 [V] or more), corrosion of the coating progresses. . However, if the constant current Is is too low, a proper diagnosis cannot be made.
Therefore, the diagnosis of the coating film must be performed by applying a constant current Is of a certain value or higher within a range in which the voltage Vs does not exceed a predetermined value.

However, in the conventional coating film diagnostic apparatus, for example, it is necessary for the user to switch the range, and even if the range is switched, it takes time until the constant current Is changes. Therefore, it was difficult to adjust the constant current Is during diagnosis. FIG. 4 shows this point. As shown in the waveform of the first example circled in the figure, when the charging waveform is completed, the voltage Vs does not exceed 0.1 [V] and the discharge is continued as it is. Diagnosis can be made. This indicates that the constant current Is is an appropriate current value.

On the other hand, when the voltage Vs exceeds 0.1 [V] in the process of charging, as in the waveform of the second example marked with a cross in the drawing, or when the waveform of the third example marked with a cross in the drawing If the current value of the constant current Is is too low, the diagnosis cannot be properly performed. However, as described above, in the conventional coating film diagnostic apparatus, it was difficult to adjust the constant current Is during the diagnosis, so the diagnosis had to be redone. Therefore, it took a long time to complete the diagnosis.

In contrast, the coating film diagnostic apparatus 10 of the present embodiment does not require range switching, and the CPU 111 can appropriately change the current value of the constant current Is based on the measurement data. Therefore, as shown in the waveform of the fourth example circled in the figure, the current value of the constant current Is is changed after a predetermined time T1 (for example, 10 seconds) has elapsed since the application of the constant current Is was started. By doing so, the diagnosis can be completed without redoing the diagnosis. In other words, according to the present embodiment, it is possible to shorten the time until the end of diagnosis as compared with the conventional art.

<Modification>
The above-described embodiments are preferred embodiments of the present invention, but the scope of the present invention is not limited only to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. can be implemented.

For example, in the above-described embodiments, the coating film is diagnosed using a constant current circuit. By modifying this, the diagnosis of the coating film may be performed by a constant voltage circuit. In this case, as shown in FIG. 6, the D/A conversion circuit 151 that applies a constant current is replaced with a D/A conversion circuit 154 that applies a constant voltage.

Then, the CPU 111 generates control data for applying a constant voltage and outputs it to the D/A conversion circuit 154 . Also, the D/A conversion circuit 154 outputs a constant voltage based on the control data.

By such modification, the current Is input to the current log amplifier 152 changes like the waveform of the fifth example shown in FIG. The CPU 111 can diagnose the coating film based on the measurement data generated from the changing current Is.

In the case of this modification, the voltage Vs obtained by multiplying the resistance components of the coating film and the substrate exceeds a set constant voltage (for example, a constant voltage of less than 0.1 [V]) There is no Therefore, it is possible to prevent re-diagnosis as described with reference to FIG.

The coating film diagnosis apparatus 10 described above can be realized by hardware, software, or a combination thereof. Moreover, the coating film diagnostic method performed by the coating film diagnostic apparatus 10 can also be realized by hardware, software, or a combination thereof. Here, "implemented by software" means implemented by a computer reading and executing a program.

The program can be stored and delivered to the computer using various types of non-transitory computer readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible discs, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical discs), CD-ROMs (Read Only Memory), CD- R, CD-R/W, semiconductor memory (eg, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)). The program may also be delivered to the computer by various types of transitory computer readable medium. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transitory computer-readable media can deliver the program to the computer via wired channels, such as wires and optical fibers, or wireless channels.

10 coating film diagnosis device 11 control board 111 CPU
112 ROMs
113 RAM
114 Bus 12 LCD display 13 SW group for setting 14 USB connector 15 Analog boards 151, 154 D/A conversion circuit 152 Current log amplifier 153 A/D conversion circuit 16 Battery 17 Spacer 18 First electrode 19 Second electrode 20 Magnet part 21 housing

Claims (5)

a first electrode disposed on a substrate on which a coating film to be diagnosed is formed;
an applying means for applying a predetermined electrical signal to the first electrode;
a second electrode disposed on the surface of the coating film;
conversion means for outputting a voltage obtained by logarithmically converting the current flowing through the second electrode based on the predetermined electrical signal applied to the first electrode ;
Control means for acquiring the voltage value of the voltage output from the conversion means as measurement data that serves as diagnostic information on the coating film;
an A/D conversion circuit that analog-to-digital converts the voltage output from the conversion means and outputs the voltage to the control means;
with
The application means is a D/A conversion circuit that digital-analog converts the control data output from the control means and outputs it as the predetermined electric signal,
The coating film diagnosis apparatus, wherein the control means controls the application of a predetermined electric signal by the applying means based on the measurement data, thereby making the predetermined electric signal a constant-current electric signal. a first electrode disposed on a substrate on which a coating film to be diagnosed is formed;
an applying means for applying a predetermined electrical signal to the first electrode;
a second electrode disposed on the surface of the coating film;
conversion means for outputting a voltage obtained by logarithmically converting the current flowing through the second electrode based on the predetermined electrical signal applied to the first electrode ;
Control means for acquiring the voltage value of the voltage output by the conversion means as diagnostic information on the coating film;
with
The coating film diagnostic apparatus, wherein the control means controls the application of the predetermined electric signal by the applying means so that the predetermined electric signal is a constant-voltage electric signal. 3. A coating film diagnosis apparatus according to claim 2, wherein said control means controls application of a predetermined electric signal by said applying means based on the voltage value of the voltage output from said conversion means. The control means controls the application of the predetermined electric signal by the applying means during a period from the start of acquisition of the diagnostic information to the end of acquisition of the diagnostic information. Item 4. The coating film diagnosis device according to any one of Items 1 to 3. The control means diagnoses one or both of the state of the coating film and the state of the substrate based on the diagnostic information,
The coating film diagnostic device further comprises an output means for outputting the result of diagnosis by the control means,
5. The coating film diagnosis apparatus according to any one of claims 1 to 4, characterized in that:

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