CS636688A3 - Apparatus for determining piping corrosion - Google Patents

Description

1

Detection equipment

Corrosion technology

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a device for detecting corrosion of a pipe deposited on a support or attached by a clip, the area in which the pipe lies on a support or in a clip, using gamma-rays or X-rays with its recording. for radiographic film to detect external corrosion of pp 'AIA IV....

Background Art

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It is known that pipes in industrial plants often suffer from corrosion. This applies both to the pipeline being used and to the pipeline that is currently out of service. For this reason, the condition of the material from which the pipe is made needs to be carefully checked.

In particular, corrosion occurs at the outer wall of the pipe where the pipe rests on the substrate or is fixed by clamps or clips. Corrosion is also easily achieved, for example, under the coating of the lacquer or on the inside of the pipe in the areas mentioned.

Corrosion can be demonstrated by physical procedures. These methods can be used to determine whether a light, moderate or heavy damage to the material from which the pipe is made is running, as is the remaining pipe wall thickness. - 2 - U. '.s' ·' '', -. i, '·'. '-.Í.-' i '. ·, I: · <.

It is known that such measurements can be carried out by means of sound (Dechema-Factsheet ZFP2-February 1984 "Piping from Metallic Materials to Corrosion Damage"). To carry out the test, the piping must be raised at least 100 mm and polished at the test site.

The same Dechema information sheet also provides gamma-ray testing. In this case, however, the pipe must also be lifted by at least 50 mm.

Raising pipes usually creates great difficulties. The pipes must be taken out of service, cleaned, lifting mechanisms depending on the pipe size, sometimes heavy duty. In addition, it is usually necessary to switch off the equipment that is connected to the pipeline and consequently production losses.

Another disadvantage in conventional tests is the risk of pipe breaks in areas of increased corrosion during lifting.

Also, in the case of devices, for example for the treatment of contaminated products such as waste water, waste gases, etc., where the process cannot be interrupted, it is necessary to ensure operation, for example, by a very expensive reserve pipe.

Therefore, there remains a problem of how to make the pegs without the need for a timely removal of the examined pipeline and thus disconnection of the equipment connected through the pipeline. 3

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The present invention relates to a device for detecting corrosion ducts embedded on a support or attached by clips, in a region in which the ducts lie on a support or in a clip, using gamma-rays or X-rays with its recording on a radiographic film. detecting external corrosion in the area of the pad or under the fasteners, the solution that the source of gamma-rays or X-rays is deposited on one side of the pipe on one side of the pad or the clip and the radiographic film is placed on the other side of the pipe and on the side of the pad or clip, wherein the central joining line between the radiation source and the radiographic film forms with the longitudinal axis of the pipe an angle of 30 to 75 ° and, in the case of a 50 to 70 ° hook, the radiation source is positioned with respect to the surface of the pad in the vertical direction, the bottom edge of the radiation being is located in the 5D range above the surface of the substrate and, in the case of a clip, the center of the radiation source is disposed between 25D below and 25D above the inner surface of the clip, where D is the diameter of the radiation source, the radiation and / or the radiographic film being deposited within 100 cm of the mat of the mat and pipe or the intersection of pipes and clamps.

The pipe is very often placed on racks or other pads and rests on them in a certain position. When using the device according to the invention, it is also possible to test the inner and outer walls in the area of these washers and thus to determine the corrosion in these areas. - 4 -

The method used is known to illuminate the test site and obtain the image on the film. However, in the case of the device according to the invention, it is not necessary to lift the piping from the substrate, it is not necessary to clean or polish it at the test sites and it is also not necessary to unset the devices which are connected by piping.

Gamma sources and X-rays for corrosion detection are known per se. In the case of gamma-rays, sources are usually used, which are small radioactive bars with a diameter of only a few millimeters. The radioactive material is usually iridium or cobalt. However, other radioactive materials may also be used. The radiation source is usually located in the working or shipping container. During the tests, the radioactive source can be moved and optionally removed from the end by a remote control tube, whereby the source can be placed in the test position.

The source of grit in the container is usually placed in a stable shelf with the appropriate trim on the side of the substrate or duster. On the other hand, a fixed radius of the radical film is attached to the device by adjusting the tray to provide the radiation that passes through the bevelled area to operate the film and / or image it. In particular, X-ray films can be used for films. Preferably, a combination of film and crosslinking film is used. The use of this combination can reduce the exposure time by at least 90%. This is important in terms of exposing the human body because radiation is limited to a small area and the exposure takes a very short time. t: fc, t:

The intensity and wavelength of the radiation source for said radiation; . . The uses are known and need not be explained in more detail. ;

The radiation source used may have different activities, which is also the case. known. A preferred source of radiation for this use is a source of gamma-radiation with different activity.

The radiation source, which is usually contained in a separate housing, as described above, is brought into test position near the pad or clip such that the line connecting the radiation source and the film form an angle of 30 to 75 ° with the longitudinal axis of the pipe.

In order to obtain a sufficiently sharp image, it is necessary to store the radiation source such that its lower edge is in the range of 0.5D below to ID above the surface of the substrate, preferably 0.25D below 0.5D above the surface of the substrate, is also it can be stored at the height of the pad. D represents the diameter of the radiation source. s · i Λ,

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For example, if the radiation source has a diameter of 1.6 mm, _? it is possible to place a lower edge of the source of 0.8 mm, preferably 0.4 mm, preferably up to the height of the substrate. Further, the lower edge may be 1.6 mm, preferably 0.8 mm above the pad, preferably at the height of the pad. g .sW-is v .-. '<· ιΐ- »· ... <' kT-LJ-i · '-ϋ' ^ Λ 6 -X-, ·; 4- · - .. The radiation source is s it is advantageously stored centrally in the elevation of said line and near the substrate. In the case of clamps, the overlapped pipe area can be tested all over the circuit. The distance between the radiation source and the film and the intermediate point where the pipe touches the pad or where it is in contact with the clip may be up to 100 cm, preferably below 50 mm, the shortest possible distance being preferred.

Thus, the radiation source and the film may be deposited at the aforementioned heights within a 100 cm or smaller radius.

The film is stored in such a way that it is possible to obtain a sufficient contrast image after exposure to detect corrosion. Preferably, two exposures are performed. ·. · 'Multiple exposures can be made in principle.

It has to be taken into account that one-way exposure does not provide a result that can be well evaluated, except in those cases where the surface of the pad is sufficiently small and the pad is narrow enough. with i · y

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• 7 · -x- x Analogously to the tether clips, '·'. 1 ^ 4 ’- only one episode is sufficient if the catch is narrow enough. In the case of two exposures, the procedure is preferably such that, in the case of a second exposure, the source of radiation and the film are deposited on the opposite side of the mat or clip, but on the same side of the conduit or on the opposite side of the conduit and the opposite side of the mat or catch .

A particularly advantageous effect of the process according to the invention is the fact that the piping is not required to be lifted over the substrate. It is not necessary to disconnect and blind the pipes. In particular, it is not necessary to switch off the equipment to which the pipe is connected.

Analogously, in the case of the sub-region, it is possible to proceed without any special preparation at this point.

As an example, the tests were carried out on an ethylene production unit with a capacity of 200,000 t / a. It might take up to 10 days to test this unit in a normal way, during which time the unit would be completely out of service. i: w; '<-> 6 -. ·. '.

SffilSsá '; J. . . : · /; ; In the process according to the invention, 6 000 tonnes of ethylene are saved in this way, which is approximately 6 000 Ό00 marks (NS -) (in

This case has been mentioned as an example only, since any pipe can be subjected to the method according to the invention. However, this example shows the importance of the method of the invention. The research has led to the result that the process according to the invention can be subjected to tests with an internal diameter of 30 to 300 mm, preferably 50 to 250 mm.

The thickness of the pipe wall has no significance in this way of detecting corrosion, since the corrosion range can be calculated from the film recording. In the event that corrosion is determined by other means, such as by direct evaluation of the images, the shape of the pipe, especially its inner space, is required to be identifiable. In these cases, the wall should not be thicker than 20 mm, the lower wall thickness is usually 1 mm, the preferred pipe wall thickness is 1 to 12 mm. 4 - X-

The same applies to wall thickness. , .....? even in internal corrosion tests. If, for example, a pipe with clamps 30 to 60 mm wide with a thickness of 5 to 10 mm is tested, the pipe wall should also be in the range of 1 to 12 mm.

It is also known that the quality of images obtained using gamma radiation also depends on the pipeline. To some extent, this is also true of the inventive tests.

The pipe material may be any conventional material, such as steel, stainless steel, but also other materials and alloys. In carrying out the process of the invention, it is not necessary to remove the insulation prior to testing. Cleaning, abrasion, polishing, lacquer removal and the like are also eliminated.

It is possible to examine not only the proximity of the pad and the clip, but also the surrounding area. According to the exposed radiographic film, the remaining wall thickness can be easily calculated by correlating the distance between the source of radiation and the center of the pipe and the distance between the radiation source and

Wfpri 10 film to the actual wall thickness and wall thickness as shown in the picture. In this way, abrasion, pitting and other types of corrosion can be easily detected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The drawing overview is explained in detail in connection with the

In the picture and film. 1 shows the position of the pipe, the radiation source

Fig. 2 shows an embodiment of the second exposure of the X-ray film.

Fig. 3 shows the source of the radiation source with respect to the intersection between the substrate and the pipe.

FIGS. 4 and 5 show tests of insulated pipes.

Fig. 6 shows a typical assembly for corrosion testing at the clip location. EXAMPLES OF THE INVENTION

1 shows a conduit 1 with an inner diameter of 250 mm and a conduit 2 with a diameter of 50 mm. Also shown is a wide pad 3 and a narrow pad 4. Also shown is a radiation source 5 and radiographic films 5, 6, 8 and 9. The angles formed by the longitudinal axis of the pipe with the central line connecting the radiation source and the center of the radiographic film are shown. - 1 ^ - wcta KUtfuWJMUkWszMMUiíauaj ·. · ?? /!

FIG. 2 illustrates an embodiment of the second exposure, the radiation source 5, and the films 6, 8 and 9 are disposed on the opposite side of the substrate.

In Fig. 3, the radiation source 5 is placed 100cm from the point of contact between the surface of the substrate and the pipe.

FIGS. 4 and 5 show an insulating conduit 11 disposed on a substrate 3. In the contacting area, it is exposed in an insulating manner. Shown is washer 3, insulation 10, pipe 7, source 5 by radiation 6. Other apparatuses are housed behind insulated pipe 1.

Fig. 6 shows a typical corrosion test in place of the clip 7. Shown is a pipe 7 in the test area, a clip 7, a radiation source 5 and a radiographic film 6. Also shown is the angle β which forms the central gamma-ray beam with the longitudinal axis of the conduit 1 and the angle θ between the central beam of gamma-radiation directed towards the center of the film 6 with the axis of the conduit 7. The following table summarizes the results that relate to the remaining wall thickness of the different wall thicknesses.

ducts determined both by the method of the invention and by direct mechanical measurement of the locations previously measured by the method of the invention, after removing the washers. From the results shown in the table, it will be appreciated that the method of the present invention provides an accurate picture of the condition of the pipe, particularly the remaining wall thickness.

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Claims (6)

/> / fa PATENT CLAIMS • r; V <\ t An apparatus for detecting corrosion of a pipe laid on a support or attached by a clip, namely an area in which the pipe lies on a support or in a clip, using a gamma-ray or an X-ray recording it, a naradiographic film for detecting the external corrosion of the pipe characterized in that the source (5) of gamma-rays or X-rays is disposed on one side of the duct (1) on one side of the washer (3) or clips (7) and the radiographic film (6) ) is disposed on the other side of the pipe (1) and on the opposite side of the washer (3) or clip (7), the central connecting line between the radiation source (5) and the radiographic film (6) forming an angle with the pipe longitudinal (1) 30 to 75 ° and, in the case of a clip, an angle of 50 to 70 °, the radiation source (5) is disposed with respect to the surface of the washer (3) in a vertical direction, the lower edge of the radiation source (5) being located in the range of 5D to ID above the surface of the pad (3) and, in the case of a clip (7), the center of the radiation source (5) is located between 25D below and 25D above the inner surface of the tab (7) where -the source (5). the radiation and / or the radiographic film (6) are stored within 100 cm of the point of contact (3) and the pipe (1) or the intersection of the pipe (1) and the clip (7). 2. Apparatus according to claim 1, wherein the radiation source comprises a gamma-radiation source. 3. Apparatus according to claim 1, characterized in that a combination of a radiological film (6) and a reinforcing film is deposited on each side of the gamma-irradiation radiation output. 4. Apparatus according to claim 1, wherein the lower edge of the radiation source is 0.25 to 0.5D above the surface of the substrate. Device according to claims 1 to 4, characterized in that, in the case of a clip, the center of the radiation source (5) is placed below 10D above the inner surface of the clip (7). Device according to one of Claims 1 to 5, characterized in that the radiation source (5) and / or the radiological film (6) are arranged within 50 cm of the contact point of the underlay (3) with the pipe (1). ), optionally from the intersection of the pipe (1) and the clip (7). Spite