JPS63317755A - Minute hole detector for underwater applied film - Google Patents

Abstract

PURPOSE:To detect a minute hole in an underwater minute hole with good reliability, by providing a partitioning outer wall so as to surround a detecting electrode, insulating the water around the detecting electrode from the outside, and detecting the presence or absence of a current which is detected under this state. CONSTITUTION:An elastic tube body 14 is provided at the tip of a sensor part 1, in which an electrode part 13 is contained. Before an applied film S on a structure member F to be checked, which is arranged in the water, is checked, the elastic tube body 14 of the sensor 1 is compressed to the applied film S. The water around the electrode part 13 and the water at the outside of the elastic tube body 14 are electrically insulated by the compression. Under this state, a switch 24 in a measuring part 2 is closed, and a voltage is applied between the structure member F and the electrode part 13. When a minute hole Sa is present in the applied film S1, a large current flows through the electrode part 13. This current is detected with the measuring part 2, sent to an X-Y recorder 3 and recorded on recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an underwater coating film micropore detection device that detects micropores in a coating film applied to the surface of a conductive structural material underwater.

[Background technology]

Conductive structural materials such as steel pipe piles for piers in coastal structures such as piers and sea berths, and steel sheet piles in ports have parts that are submerged in seawater, and the parts that are submerged in seawater are exposed to a severe corrosive environment. becomes. Of course, countermeasures such as electrolytic protection using zinc have been taken, but as time passes, the structural materials begin to corrode. In this case, one possible solution may be to replace the structural materials with new ones, but
This is not a realistic plan as it would require construction costs and fishery compensation and environmental compensation associated with the construction. So usually,
To prevent corrosion, a coating film is formed on the surface of structural materials using paints that harden even in water, such as epoxy-based underwater-curable paints, polyester-based underwater-curable paints, and vinyl ester-based underwater-curable paints. ing.

When forming a paint film, the viscosity of the paint is high and the film thickness is relatively thick, about 1 to 5 meters. In addition to the spreading method, methods such as applying with a spatula, trowel, or roller are also used. In such a coating film manually applied in water, micropores (about 2 to 3 mm in diameter) are likely to be formed due to unpainted areas.

If there are micropores in the paint film, the surface of the structural material will be directly exposed to seawater, leading to accelerated corrosion of the structural material. To prevent this, after the paint film is formed, a dipper dives and visually inspects the paint film for micropores, and if any, they are repaired.

However, such detection work that relies completely on visual inspection takes time. Daiper cannot perform detection work continuously for long periods of time due to limitations on diving time. It takes a long time to complete the work. In addition, the test results are easily affected by seawater transparency, water depth, etc., and there are individual differences in the judgment itself, making the test results less reliable. May-October
During the month, red tide occurs in some places. In this case, transparency is significantly reduced and inspection becomes extremely difficult.

[Purpose of the invention]

The purpose of this invention is to provide a micropore detection device for underwater paint films that is less affected by seawater transparency, water depth, etc., provides objective and reliable detection results, and can efficiently perform micropore detection work. shall be.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides an apparatus for detecting micropores in a coating film applied to the surface of a conductive structural material in water, comprising an electrode section for detecting the micropores. A sensor means is provided, and a measuring means is provided for measuring a signal related to an impedance value between the electrode section and the structural material, and the sensor means is connected to an insulating elastic material surrounding the electrode section. The underwater device further comprises a partition wall, and when detecting micropores, the partition wall is brought into contact with the coating film to prevent the electrode portion from being electrically connected to water outside the partition wall. The gist of this paper is a device for detecting micropores in paint films.

Hereinafter, the underwater coating film micropore detection device according to the present invention will be described below.
One embodiment will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows the general structure of a micropore detection device for an underwater coating film (hereinafter referred to as "micropore detection device") according to the present invention. Figures 2 (a), (b), and (C) show the sensor section of this microhole detection device.

FIG. 3 shows how the microhole detection device is used.

The micropore detection device consists of a sensor section (sensor means) 1 that is brought into the water and used by applying it to the coating film S, and a measurement section (
It consists of a measuring means) 2 and a recording section (in this embodiment, an X-Y recorder) 3. Necessary electrical connections between the sensor section 1, the measurement section 2, and the recording section 30 are made by cables 4.5, respectively.

The sensor section 1 includes a body 10 made of an insulating material, and the body 10 is provided with an electrode section 13 for detecting micropores and a tongue-like elastic cylinder (partition wall) 14 made of an insulating elastic material. The body 1o includes a base piece 11 and a front piece 1.
2, the base piece 11 and the front piece 12 are spring-fitted. An O-ring 16 is provided on the contact surfaces of both pieces 11, 12 to prevent water from entering the body interior space 10a from the contact surfaces.

The front piece 12 has holes 12a, as shown in FIG.
Two holes 12b are provided, one of which is the hole 12a.
An electrode portion 13 is attached to the hole 12a, and a pressure sensitive element 15 is attached to the other hole 12a so as to receive water pressure. The elastic cylinder 14 has a stepped portion 1 provided on the side surface of the front piece 12.
It is fitted into 2c.

A switch 17 for controlling application/non-application of voltage between the electrode section 13 and the structural material F is attached to the side surface of the base piece 11. As will be described later, a voltage is applied between the electrode section 13 and the structural material F only while this switch 17 is pressed. An alarm 18 is attached to the rear surface of the base piece 11 to notify that a microhole has been detected.

The measurement section 2 includes a power supply section for applying an alternating current voltage between the structural material F and the detection electrode section 13, a current measurement section that measures the current flowing between the structural material F and the detection electrode section 13, and A water depth measuring section of the sensor section 1 and the like are provided. The current measured by the current measuring section is a signal related to the impedance value (in this case, the resistance value) between the structural material F and the electrode section 13.

The power supply section is an AC oscillator (the oscillation frequency is usually 50 to 2
000 Hz) 21 and a voltage regulator 22. The AC output of the AC oscillator 21 is adjusted to an appropriate value by a voltage regulator 22, and is applied between the structural material F and the detection electrode section 13 via a switch 24 and a detection resistor 25.

The current measuring section includes a detection resistor 25, and this resistor 25
, a voltage proportional to the amount of current flowing through the structural material F and the detection electrode section 13 is generated. This voltage is amplified by an amplifier 26 and then converted to a DC signal by an AC-DC converter 27.
-It is output as a Y-axis signal of the Y recorder 3 and is also sent to the current indicator 28 to indicate the amount of current. In addition,
The AC-DC converter 27 also outputs a notification signal to the notification device 18 when the amount of current exceeds a certain amount.

The water depth measurement section detects a signal from the pressure sensitive element 15 provided in the sensor section 1 with the detection section 29, amplifies it with the amplifier 30, converts it into a signal according to the water depth, and sends a Y-axis signal to the X-Y recorder 3. At the same time, it is sent to the water depth indicator 31 to indicate the water depth. 32 is a power source for driving the pressure sensitive element 15. The pressure sensitive element 15 may be, for example, an element in which a strain gauge resistor is formed on the surface of a thin diaphragm made of single crystal silicon, or an element in which a strain gauge resistor is formed on an insulating layer on the surface of a metal diaphragm. elements etc. are used.

The elastic cylinder 14 plays the following important role. In the microhole detection work, as shown by the dashed line in Figure 1,
When the elastic cylinder 14 is pressed against the coating S1 of the conductive structural material F, the electrode portion 13 is in electrical contact with the coating S1 on the inside of the elastic cylinder 14, or is in contact with the coating S1 on the outside of the elastic cylinder 14. The purpose is to prevent electrical contact with the coating film S2. When detecting micropores in an underwater coating film, conductive water is present on the entire surface of the coating film S, and simply applying the electrode section 13 without the elastic cylinder 14 to the coating film S will cause damage to the spot where it was applied. Even if there are no micropores, if there are micropores elsewhere, current will flow to the electrode section 13 through the water. Therefore, even if it is known that there is a microhole, it does not mean that the hole is located at the place where the electrode part 13 is applied.
No information is available about the location of the holes. Elastic cylinder 1
4 provides information regarding the position of the micropores.

When the elastic cylinder 14 is pressed against the coating film S, the elastic cylinder 1
4 has insulating properties, the water inside the cylinder 14 and the water outside the cylinder 14 are electrically insulated. Therefore, the electrode part 13 is electrically connected to the coating film S1 inside the elastic cylinder 14 through the water filling the inside of the elastic cylinder 14.
Since it is insulated from the water outside the elastic cylinder 14, it is not electrically connected to the coating film S2 outside the elastic cylinder 14. Paint film S1
If there are micropores in the electrode section 13, a current flows through the electrode section 13. If there are no micropores in the coating film S1, no current will flow through the electrode portion 13 even if the coating film S2 has micropores. This is because the coating film S2 and the electrode section 13 are electrically insulated. Therefore, when a current flows through the electrode portion 13, there will always be micropores in the coating film S1. In other words, this coating 11
'ff51 location can be specified. If no current flows through the electrode portion 13, no micropores exist in the coating film S1. Of course, the degree of prevention of electrical conduction inside and outside the cylinder may vary depending on the way the elastic cylinder 14 is pressed, the state of the coating film S1, etc., but the degree of prevention of electrical conduction depends on the presence or absence of micropores. This may be done within a range that does not hinder the determination.

A switch 17 is also provided in connection with the presence of water as described above. The switch 17 is turned on, and the structural material F/electrode part 1
If a voltage is always applied between 3 and the sensor part l is separated from the coating film S, current will flow from all the micropores of the structural material F, and a high current will flow to the X-Y recorder 3. recorded, making it difficult to distinguish from the recording made during the actual detection operation.

Next, a description will be given of how the detection device is used to detect micropores in a coating film.

As shown in Fig. 3, the measuring part U and the structural member F are connected with an electric wire 8, and the Diaper D dives with the sensor 1.
As shown in FIG. 1, the elastic cylinder 14 of the sensor section 1 is pressed against the coating film S, and the switch 17 is pressed. This switch 17
While pressing , the switch 24 of the measuring section 2 is closed in conjunction. When the switch 24 is closed, the structural material F and the electrode part 13
A voltage is applied between them.

If there is no micropore Sa in the coating film S1 inside the elastic cylinder 14,
The current flowing through the electrode portion 13 is only an extremely small base current determined depending on the insulation resistance of the coating film S. Micropore Sa
If there is, conduction will occur between the electrode section 13 and the structural material F through the water, so that the current flowing through the electrode section 13 will far exceed the base current. Of course, the current is measured by the current measuring section and sent to the XY recorder 3.

On the other hand, the water depth measuring section sends a signal corresponding to the water depth of the sensor section 1 to the XY recorder 3. Further, a marker signal indicating the timing when the switch 17 is pressed and the detection operation is performed is also sent to the X-Y recorder 3.

Diaper D sequentially applies the sensor section 1 from the shallow side to the deep side of the water and repeats the detection operation until a predetermined depth is reached. at the same time,
The detection results are also recorded by the XY recorder 3.

Figure 4 shows the recording paper on which the detection results are recorded. The amount of current is recorded on the recording paper in correspondence with the water depth. On the left end of the recording paper, markers M . . . M are recorded corresponding to the timing when the switch 17 is pressed to perform the detection operation. Peak P recorded alongside marker M
. . . P indicates that the amount of current was large in the detection operation due to the existence of a microhole. However, marker M
A peak P' without a marker M indicates a large amount of current, but it is a noise current when no detection operation is being performed, and therefore a peak P' without a marker M
does not indicate that there were micropores.

In addition, when a current exceeding a predetermined value flows during the detection operation (when there is a peak P), a signal is sent from the measuring section 2 to the alarm 18 of the sensor section 1 (notification is made by light or sound, etc.). This notifies the dialer that the microhole Sa has been detected. Diaper D searches for and repairs micropores Sa (
or leave a mark indicating that repair is required). When there is no notification from the notification device 18, the process immediately moves to the next detection operation.

When the detection operation up to a predetermined depth is completed, the probe returns to the initial water depth, shifts a predetermined distance in the horizontal direction, and repeats the detection operation in the deeper direction again. In this way, the detection work is performed over the entire surface of the coating film S of the structural material F.

With the micropore detection device described above, it can be immediately determined whether or not there are micropores within a predetermined area. Moreover, the determination of the presence or absence of micropores is based on current measurement (objective). Even if there is a micropore, it is only necessary to examine within a predetermined area, so the search for micropores can be performed extremely quickly. The time required for the detection work can be shortened.Moreover, the inspection results corresponding to the depth can be recorded on the chart as described above.Therefore, the reliability and reliability of the inspection results are high.

Although the microhole detection device of the above embodiment was not provided with a means for detecting the position in the horizontal direction, it would be more convenient if the device was provided with a means for detecting the position in the horizontal direction.

An example of a means for detecting a position in the horizontal direction is as follows. An ultrasonic oscillator is attached to the sensor section. On the other hand, a receiver is provided in which a large number of ultrasonic receiving elements are arranged along the horizontal movement range of the sensor unit, and the position of the ultrasonic element that is most strongly received is detected as the horizontal position of the sensor unit at that time. do.

Furthermore, instead of having the sensor part supported by the dialer's hand,
The robot is designed to automatically move and detect vertically and horizontally on the paint film of the structural material, and outputs signals according to the amount of vertical and horizontal movement from the reference position. You may also leave it as such.

Next, a second embodiment of the microhole detection device according to the present invention will be explained.

The microhole detection device shown in FIG. As shown in the figure, it is opened on both sides using a hinge 42 as a fulcrum.A plurality of electrode parts 44, which are individually surrounded by a partition wall 43, are provided on the inner circumference of the annular body 41. A pressure sensitive element 45 is provided within one partition wall 43.

When in use, as shown in FIG. 6, the annular body 41 is wrapped around a cylindrical structural member F (of course coated with a coating film), the grips 46 and 46 are tightened, and the partition wall 43 is coated. Press against the membrane.

As shown in Fig. 7, the measurement section of this microhole detection device is as follows.
A current measuring section I is provided for each electrode section 44. The signals from each current measuring section (2) and water depth measuring section H are digitized by an input interface 51 and input to a personal computer 52. personal computer 53
Then, the input signals are processed, and a data sheet as shown in FIG. 9 is printed out on the printer 53, and data as shown in FIG. 10 is displayed on the monitor 54. On the monitor 54, a circle is displayed when a certain amount of current or more flows. At that time, it is convenient to associate the display with the size of the micropore to some extent by making the circle mark color-coded according to the amount of current.

Further, the detection results may be stored on the disk 55.

In addition, as shown in FIG. 8, the measuring section is a multiplexer MX which has only one current measuring section I and connects each electrode section 44 to the current measuring section 2 in turn by a signal from the switch 17.
The configuration of the measuring section may be simplified by providing the following.

In the microhole detection device of the third embodiment shown in FIGS.
An example of the vertically long body 61 includes a partition wall 62.
A plurality of electrode portions 63...63 are provided which are individually surrounded by. A pressure sensitive element 64 is provided inside the partition wall 62.

The configuration of the measuring section and the like is the same as in the second embodiment.

In the second and third embodiments, detection operations can be performed at a plurality of locations at the same time, so that work efficiency is further improved. Also, in the microhole detection devices of these embodiments, it is convenient if the sensor sections 1', 1'' are provided with an alarm.

The microhole detection device according to the present invention is not limited to the embodiments described above.

Previously, micropores were detected by measuring the current flowing through the electrode, but it was also possible to configure an oscillator that includes the impedance between the electrode and the structural material and measure the oscillation frequency. Detection of micropores may also be performed.

The present invention is not limited to newly applied coatings, but may also be used to check whether micropores have occurred in already applied coatings.

The voltage applied between the structural material and the electrodes must not be alternating current (direct current is also acceptable. However, if direct current is used, the electrodes may be damaged by electrolysis, or the current value may take a long time to stabilize, resulting in poor response). It is preferable to use alternating current because of its low sensitivity.

Although the sensor section and the measurement section are separated, the sensor section and the measurement section may be integrated.

The position of the sensor means is detected by tightening a chain between the sensor means and the surface of the water, visually measuring the position and amount of extension of the chain, and manually inputting the results as a position signal to the measuring section. You can do it like this.

The structural material may also be a structural material constituting the wall of an offshore petroleum storage tank. Further, it is convenient to configure the structure so that a voltage is automatically applied between the electrode portion and the structural material while the elastic cylinder is pressed against the coating film. The structural material is usually made of a metal material, but it does not necessarily have to be a metal material, but the closer the conductivity is to that of the metal material (the lower the conductivity), the better the detection accuracy of micropores will be. Needless to say, it is good.

On days when the waves are rough, the water depth changes from moment to moment by the height of the waves. It is convenient to provide a fixed pressure-sensitive element separately, detect the variation, use the detected variation to remove and correct the variation in the pressure-sensitive element of the sensor part, and perform accurate water depth measurement. Alternatively, an ultrasonic oscillator is installed in the sensor section, and a receiver placed on the water surface detects the signal directly received from the oscillator and the signal reflected at the bottom of the water, and the sensor section detects the time difference between these signals. By determining the height from the bottom of the water and using this as the position of the sensor unit, fluctuations due to the influence of the waves can be removed.

〔Effect of the invention〕

Since the micropore detection device according to the present invention has the above-described configuration, it is less affected by seawater transparency, water depth, etc., provides objective and reliable inspection results, and can be operated efficiently and in a short time. I can do it.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a micropore detection device for an underwater coating film according to the present invention, and FIGS. te, figure+
Figure (a) is a front view, figure (b) is a bottom view, and figure (e) is a plan view. FIG. 3 is an explanatory diagram showing how the micropore detection device is used, FIG. 4 is a chart recording the detection results of the micropore detection device, and FIGS.
FIG. 6 is a schematic view of the sensor section of the second embodiment of the microhole detection device according to the present invention, (al is a perspective view, FIG.
is a plan view, FIG. 6 is a perspective view showing the state of use of this sensor section, FIGS. 7 and 8 are block diagrams of the measuring section of the second embodiment, and FIG. 9 is a diagram of the second embodiment. FIG. 10 is a plan view of the data sheet recording the detection results by the microhole detection device of the embodiment, and FIG. 11 is an explanatory diagram of the monitor display of the detection results by the second embodiment. FIGS. FIG. 3 is a diagram illustrating a sensor section of a microhole detecting device according to a third embodiment of the present invention; FIG. l, 1', 1"...sensor section (sensor means) 2...
Measuring part (measuring means) 13.44.63... Electrode part 14... Elastic cylinder (partition wall) 43.62...
・Partition wall F...Structural material S...Painting film Sa...
・Microhole Agent Patent Attorney Takehiko Matsumoto No. 1 Figure 136 Figure 9 Figure 70

Claims (7)

[Claims] (1) A device for detecting micropores in a coating film applied to the surface of a conductive structural material in water, the device being provided with sensor means equipped with an electrode section for detecting the micropores, and , a measuring means for measuring a signal related to an impedance value between the electrode part and the structural material is provided, and the sensor means also includes a partition wall made of an insulating elastic material surrounding the electrode part, A device for detecting micropores in an underwater coating film, characterized in that when detecting micropores, the partition wall is brought into contact with the coating film to prevent the electrode portion from being electrically connected to water outside the partition wall. (2) The underwater coating film micropore detection device according to claim 1, wherein the signal related to the impedance value between the electrode portion and the structural material is a current flowing between the electrode portion and the structural material. (3) An apparatus for detecting micropores in an underwater coating film according to claim 1 or 2, which is provided with position detection means for detecting the position of the sensor means. (4) The position detecting means is a means for detecting the water depth of the sensor means, and this means is a patented patent that includes a pressure sensitive element for detecting water pressure provided in the sensor section and a water depth measuring section provided in the measuring means. A device for detecting micropores in an underwater coating film according to claim 3. (5) Claims 1 to 4, wherein the sensor means includes an alarm that notifies that the microhole has been detected.
2. A device for detecting micropores in an underwater coating film according to any one of the preceding paragraphs. (6) Any one of claims 1 to 5, wherein the sensor means includes a plurality of electrode sections individually surrounded by partition walls, and the measurement section measures the signal for each electrode section. A device for detecting micropores in an underwater coating film as described above. (7) The underwater coating film micropore detection device according to any one of claims 1 to 6, wherein the sensor means includes a switch, and the measurement operation by the measurement means is controlled by operating the switch. .