JPS6034066B2 - Magnetic particle testing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION With the development of ocean development, various underwater structures have appeared and been used for a long time, but recently the need for their maintenance and repair has been increasing.

One of these related technologies, underwater non-destructive testing, has a short history of development, is technically incomplete, and has not yet been put into full-scale practical use. The underwater magnetic particle deep flaw method is promising as a nondestructive inspection method for surface defects in underwater structures, but the conventional method shown in FIG. 1 has the following problems. In addition, 1 in FIG. 1 is a magnetizing device, 2 is a magnetizing device power supply, and 3 is a magnetizing device.
4 is a test liquid container, 4 is a structure to be inspected, 5 is a test magnetic powder, 6 is a test liquid, 7 is a magnetic flux, 8 is a defective part, and 9 is a water flow. Now, in the inspection method shown in Fig. 1, since the inspection magnetic particles 5 are sprayed directly onto the inspected structure 4 in water, they are susceptible to the influence of surrounding water such as the water flow 9, which disturbs the magnetic particle pattern and makes it difficult to detect defects. However, compared to land, there was a drawback that it was lower in the middle of the season. Furthermore, a large amount of magnetic powder escapes into the seawater, which not only makes it uneconomical as it requires a larger amount of magnetic powder than necessary, but also causes pollution of the surrounding seawater. The present invention was proposed to solve the above-mentioned conventional drawbacks, and it is possible to obtain the same defect detection ability underwater as on land, is economical, has no sign of marine pollution, and has a magnetic particle depth. The purpose is to provide a wound treatment device. Embodiments of the present invention will be described below with reference to the drawings.

In the apparatus according to the embodiment of the present invention shown in FIGS. 2 to 4, the same parts as in FIG. 1 will be described using the same reference numerals. Now, in FIG. 2, the inspection cassette 10 is installed between the magnetic poles N and S of the magnetization device 1 placed on the underwater structure 4 to be inspected. This cassette 10 is connected to a test liquid supply pump 13 via a connecting hose 12 via a differential pressure detector 11. Further, the differential pressure detector 11 is electrically connected to the test liquid supply pump 13 via the controller 14. In addition, in Fig. 2, 2 is the magnetization device power supply, 5 is the magnetic powder for inspection, 6 is the inspection liquid,
7 is a magnetic flux, 8 is a defective part, 9 is a water flow, and 15 is a motor. The inspection cassette shown in FIG. 2 is the most distinctive feature of the present invention, and its detailed structure is shown in FIG. 3.

Thirdly, the inspection cassette 10 is a transparent sealed container composed of a transparent solid 10a (for example, glass, transparent resin, etc.) on the top and side surfaces and a non-conductive elastic thin film 10b on the bottom. is filled with test water 6 (suspension of water, white kerosene or alcohol and magnetic powder 5). Next, to explain the operation, the differential pressure detector 11 attached to the test cassette 1 detects the differential pressure between the internal pressure due to the test liquid 6 in the cassette 10 and the external water pressure outside the cassette 10, and the controller 14 compares this detected signal with a preset differential pressure signal, and if the differential pressure between the internal pressure of the cassette and the outside water pressure is lower than the preset differential pressure, the test liquid supply pump 13
to maintain the pressure inside the cassette slightly higher than the outside water pressure.

This differential pressure slightly expands the non-conductive elastic thin film 10b, so even if there are irregularities on the surface of the underwater structure 4 to be inspected as shown in FIG. do. After installing the inspection cassette 10 on the surface of the underwater structure 4 to be inspected by the above method, when a current is passed from the magnetization device power supply 2 to the magnetization device 1 to magnetize it, the magnetic flux 7 is disturbed by the defective part 8, and leakage magnetic flux reaches the inside of the inspection cassette 10 through the non-conductive elastic thin film 10b, and a clear magnetic particle pattern is drawn on the non-conductive elastic thin film 10b by the magnetic particles 5 without being affected by external water flow.

Therefore, it is possible to inspect for defects using the same principle as the normal powder flaw detection method used on land. As explained in detail above, the present invention is structured, and the test liquid containing magnetic particles is filled in a test cassette made of a transparent sealed container, so the test liquid is non-consumable and does not contaminate seawater. Moreover, since the magnetic particle pattern is not disturbed by the water flow, defect inspection performance can be improved to the same level as on land.

In addition, the present invention can control the test solution supply pump so that the pressure inside the cassette is slightly higher than the outside water pressure using the differential pressure detector and controller attached to the cassette filled with the test solution containing magnetic particles. The elastic thin film of the cassette expands slightly and adheres to the underwater structure even if the surface is uneven or the water depth changes. Therefore, the present invention is effective as a device for performing maintenance, inspection, and inspection of underwater structures, and by putting magnetic particles into an inspection cassette, it can be used efficiently (can be used repeatedly), so it can be applied to land inspection technology. It is also promising for application to

[Brief explanation of the drawing]

Figure 1 is a side view of a conventional underwater magnetic particle testing device;
The figure is a side sectional view of a magnetic particle flaw detection method implementation device showing an embodiment of the present invention, and Figure 3 is an enlarged view of the main parts of Figure 2. Device, 2... Magnetizer power supply, 4... Underwater structure to be inspected (inspected object),... Magnetic powder for inspection, 6... Test liquid, 7
...Magnetic flux, 8...Defect, 10...
...Inspection cassette, 10a...Transparent solid (transparent sealed container), 10b...Non-conductive elastic thin film. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An inspection force set consisting of a transparent container filled with a test solution containing magnetic particles in the inspection area of the underwater structure to be inspected and having at least a non-conductive thin film on the surface that contacts the underwater structure, is placed at a pressure equal to the internal pressure caused by the test solution. A differential pressure detector is included to detect the surface pressure between the water pressure outside the cassette, and the signal from this differential pressure detector is compared with the differential pressure signal set in advance by the controller, so that the pressure inside the cassette is always slightly higher than the outside water pressure. 1. An apparatus for carrying out a magnetic particle flaw detection method, characterized in that a detection liquid feeding pump is driven so that the magnetic particle height increases, and a magnetic particle pattern due to leakage magnetic flux is drawn on the thin film by magnetic particles in a cassette.