JPS61271443A - Underwater radiation inspection - Google Patents

Abstract

PURPOSE:To obtain a clear inspection-picture with a simple construction, by inserting a radiation transmitting material between an object to be inspected underwater and a radiation generator to prevent the absorption of radiation by water. CONSTITUTION:A radiation transmitting material 13 in which polystilene foam is packed into a quadrangular pyramid-shaped hood 13A expanding toward the tip thereof is inserted between a radiation generator 11 and an object 14 to be inspected having a weld part 14A to inspected and tightened securely with a rubber band 15. A film cassette 21 having a film for inspecting radiation vacuum packed is arranged on the surface opposite to the object 14 being inspected and tightened securely with a rubber band 16. As the polystylene foam packed into the radiation transmitting material 13 has so numerous fine pores to absorb radiation slightly, the radiation receiving and transmitting property is improved as a whole. Thus, a clear inspection image can be obtained in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a radiation inspection method for structures, and particularly to an underwater radiation inspection method for performing a radiation inspection of an object to be inspected underwater.

[Background technology and its problems] Conventionally, when inspecting underwater structures, etc., radiation is absorbed by the water that exists between the object to be inspected and the radiation generating device, resulting in a significant increase in exposure time. The drawback was that the image quality deteriorated.

In order to prevent this absorption of radiation by water, an air chamber is provided between the object to be inspected and the radiation generating device, and a method is proposed in JP-A-53-103 that conducts inspection under conditions similar to land radiation inspection methods.
It is known as Publication No. 791. According to the method described in this publication, the exposure time and image quality are similar to those obtained on land, but it requires an air chamber and a device to supply air at a pressure higher than water pressure to the air chamber. become.

For this reason, the operability due to the structural complexity
Problems arise such as reduced reliability and maintainability, and increased testing effort and time.

[Object of the Invention] An object of the present invention is to provide an underwater radiographic inspection method that allows radiographic inspection of underwater structures to be easily performed in a short time using a simple configuration, and that allows clear inspection images to be obtained.

[Means and effects for solving the problems] The present invention has the following features:
In order to prevent the absorption of radiation by water between the inspected object and the radiation generating device, which can be an obstacle during radiographic inspection of underwater structures, a radiolucent material is inserted between them to exclude water. The purpose of this invention is to shorten the exposure time, sharpen the image quality, and facilitate handling by eliminating the need for special additional equipment.

[Example] An example of the underwater radiation inspection method of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of an apparatus according to an embodiment of the underwater radiation inspection method of the present invention, and FIG. 2 is a sectional view of the apparatus shown in FIG. 1.

In the figure, the radiation generating device 11 is a general radiation generating device, and this radiation generating device 11 is airtight, and the built-in radiation tube is designed to withstand external pressure of several atmospheres. Because of this, no particular waterproofing treatment has been applied. Further, a power cord 12 is connected to the radiation generating device 11, and power is supplied from a water power source (not shown). For the connection part, the connector is removed to prevent electrical leakage, and the wiring is directly connected. Epoxy resin is poured into a pre-made mold, and the connection part is wrapped and cured to prevent water from entering.

This radiation generating device 11 is designed to inspect an object to be inspected, which has a welded part 14A, by sandwiching a radiation transparent material 13 filled with foamed polystyrene resin having closed cells inside a quadrangular pyramid-shaped hood 13A with a widened tip side. 14, and these are fastened to each other by two rubber bands 15 having relatively strong tension to ensure fixation.

On the other hand, a film cassette 21 as a radiation image generating device is applied to the opposite surface of the object to be inspected 14, and a two-wooden rubber band 16 has a relatively weak tension to the extent that it does not compress and deform the film cassette 21. The tightening is fixed to the object 14 to be inspected. Here, the rubber band 15.
Depending on the shape of the object 14 to be inspected, the string 16 may be endless or string-like with a stopper at the end.

FIG. 3 shows a perspective view showing the inside of the film cassette.

In the figure, the film 21 is a film 22 for radiological examinations packaged in vacuum.The film 22 for radiation examinations is sandwiched between packaging films 23 from both sides, and the periphery is fused and sealed to make it waterproof. Although it is a thing,
If air is sealed inside, it is not only inconvenient to install it, but also there is a risk that the film cassette may be deformed or damaged by water pressure, so it is necessary to remove the air inside and seal the film cassette tightly. Here, as the packaging film 23 of the film cassette 21, any water-resistant plastic film such as vinyl chloride, polyethylene, polypropylene, etc. can be used.

In the apparatus of this embodiment, the radiation generating device 1
As shown in FIG. Take a picture.

At this time, the foamed polystyrene resin filled inside the radiation-transparent material 13 existing in the portion corresponding to the path of the radiation is made up of many small bubbles, and the radiation-transparent material 13 is sealed within these bubbles. While the air layer, which occupies most of the volume, has good radiolucency,
The styrene resin that forms the bubbles absorbs only a small amount of radiation, and since it is protected by the hood 13A and is not deformed by external force, there is no localized influence, and the radiation-transparent material 13 as a whole It has good radiolucency and allows clear inspection images to be obtained in a short period of time. Furthermore, in this embodiment, the structure of the apparatus is simple, including the small and easy-to-handle film cassette 21, which improves operability, reliability, and maintainability, and greatly reduces inspection effort and time.

In the above embodiment, since the object to be inspected 14 was a tube, the configuration was extremely simple by using the radiolucent material 13 and the rubber band 15 that were molded to fit closely to the tube. It is also possible to inspect walls, etc. by using the radiation-transparent material 13 in which the contact part between the mounting jig that adsorbs to the object to be inspected and the object to be inspected 14 is a mole surface, and the radiation-transparent material 13 By appropriately selecting the shape of , it can be applied to most objects 14 to be inspected.

Further, in the above embodiment, a material filled with foamed polystyrene resin inside the hood 13A was used as the radiation transparent material 13. Furthermore, other materials can be used as long as they are radiolucent.

[Effects of the Invention] As described above, according to the underwater radiation inspection method shown in the present invention, radiation inspection of underwater structures can be easily performed in a short time,
Moreover, clear inspection images can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a side view of an embodiment of the underwater radiation inspection method of the present invention, Fig. 2 is a central end view of Fig. 1, and Fig. 3 is a perspective view of the film cassette used in this embodiment with a part removed It is a diagram.

Claims (3)

[Claims] (1) Underwater radiation inspection characterized by inserting a tangible radiation-transparent material between an underwater inspection object and a radiation generating device, and irradiating radiation from the radiation generating device toward the inspection object. Method. (2) An underwater radiographic inspection method according to claim 1, characterized in that the tangible radiolucent material is plastic. (3) In claim 1 or 2, a radiographic inspection film is used as a radiographic image generating means for generating an inspection image by receiving radiation emitted from a radiation generating device and passing through an object to be inspected. An underwater radiation inspection method that uses a film cassette that is wrapped in film and sealed to exclude air.