JP2594835B2 - A method of extracting the thinned part of a double-walled pipe made of dissimilar materials and measuring the thickness of the thinned part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology is a double layer in which an outer pipe is made of a steel pipe and an inner pipe is made of a ceramic pipe, and an inner pipe is made of a pipe made of a different material. It belongs to the technical field of extracting and measuring a local thickness change phenomenon due to aging wear due to the operation of the inner pipe of the pipe.

<Summary of the Summary> Thus, as described above, the invention of this application has a double layer structure in which the outer tube and the inner tube are made of carbon steel or the like, and the inner tube is made of ceramics or the like. A thin-walled portion of a dissimilar material double-walled pipe which measures a change in wall thickness due to wear over time due to the operation of the inner pipe of the pipe by irradiating radiation such as X-rays and estimates a possible continuation time of the pipe. The present invention relates to a method of extracting and measuring the thickness of the thinned portion, and in particular, first, by irradiating the target double tube with radiation such as X-rays in a direction perpendicular to the tube surface. An image was received on a film set with line contact or the like on the back side, the density distribution of the light and shade of the photographed image was measured, and the thinning was extracted. Irradiating radiation such as X-rays or gamma rays from the direction , Through visual observation, or through electrical analysis and measurement of a photographed image, extract the thinned portion of the double-walled pipe made of a different material for which the continuous movable time is determined, and measure the thickness of the thinned portion. It is an invention according to a method.

<Prior art> As is well known, piping has become an extremely important role since it has been used not only for fluid transport but also in recent years for information transmission and strength members such as structural beams. Among them, in the primary use such as for fluid transportation, for example, applications having multiple functions such as heat resistance, pressure resistance, corrosion resistance, wear resistance, etc. simultaneously such as oil well pipes and nuclear power plant piping In many cases, pipes for these applications can be made of one kind of material that can meet all functional requirements, but cannot be made with current technology.
Double pipes made of dissimilar materials, in which the outer pipe is made of carbon steel and the inner pipe is made of stainless steel or the like and are tightly connected to each other, have come to be used.

In general, the double pipes made of dissimilar materials in the conventional mode are generally made of metal for various reasons for both the outer pipe and the inner pipe. Recently, however, the above heat resistance, pressure resistance, and corrosion resistance have been used. When functions such as abrasion resistance are required in addition to the properties, for example, a double tube made of ceramic for the inner tube has been devised and put into practical use. Due to the material and manufacturing costs, the cost of transportation to the installation site, and various other complicated problems such as management during production and operation, once installed, it cannot be replaced for a considerable period of time. There is, therefore, a need to monitor the wear of the inner tube over time during operation and to monitor when the function of the duplex tube cannot withstand further continued use.

<Problems to be Solved by the Invention> Therefore, the monitoring system for the wear and the like of the conventional double-walled pipe made of metal or the like according to the conventional aspect described above has been developed, for example, by techniques such as ultrasonic flaw detection. A technique has been developed in which an ultrasonic probe is set outside the outer tube, the degree of wear of the tube is measured by ultrasonic waves, and the operating life of the tube is measured over time. It is not possible to use the technology to measure the degree of wear for double-walled pipes of different materials such as those made of ceramics, etc. due to the properties of the measuring means, etc., and at least its effectiveness is limited was there.

In the measurement using the seed ultrasonic wave, the ultrasonic wave cannot be transmitted through the inner tube such as ceramics with respect to the irradiation of the ultrasonic wave from the outside of the outer tube, and is interposed between the outer tube and the inner tube. For example, mortar or cement, or refraction of the intermediate layer such as an adhesive, change in reflection or the like, or the ultrasonic wave irradiated by the change in transmittance, etc. to the inner tube is not reliable, and can not be sufficiently transmitted, Therefore, if the measurement is physically impossible, or if the measurement or measurement from the inside of the inner tube is to be performed, the inner tube may have a small diameter or a curved tube. Has a drawback that it cannot be used in practice.

For example, as shown in FIG. 3, the front and rear flanges 1, 2 (a,
outer tube 3 having b) at both ends is an outer tube made of carbon steel,
On the other hand, with respect to a pipe 6 in which a ceramic inner pipe 5 is provided as an inner pipe via an intermediate layer 4 of cement or the like,
The results of measuring the wall thickness of the sound source 7 by the ultrasonic flaw detection method shown in FIGS. 1 and 2 are as shown in Table 1 below. This is a measurement of the thickness of only the outer tube 3, and the measurement of the thickness of the ceramic tube 5 as the inner tube as well as the intermediate layer 4 could not be performed.

Therefore, in the future, due to new materials and material revolution, it is impossible to measure the wall thickness by ultrasonic irradiation for double tubes such as double tubes whose outer and inner tubes are made of different materials. was there.

In order to cope with this, there is a difference in the transmittance of the outer tube and the inner tube made of dissimilar materials. And the like, for example, the invention of JP-A-57-96208 and the invention of JP-A-62-277542 have been developed. In the former outer tube, the intensity of transmitted X-rays is converted into an electric signal through an image intensifier or the like by an image processing system and processed to measure the wall thickness of the pipe. In particular, the mechanism and circuit are extremely complicated, the operation requires skill, the processing operation is complicated, and the accuracy of the measured values is poor.

In the latter inner tube, a monitor tube of known thickness is used as a test tube to circumscribe the target pipe, and the circumscribed portion is X
In order to compare the photographic densities of the films by X-ray transmission, the thickness of the test tubes as well as the double tubes to be measured must be measured with extremely high accuracy. However, there is a disadvantage that it is not suitable for use as well as requires skill and requires complicated procedures for its preparation and post-processing.

<Object of the Invention> The object of the invention of the present application is that the outer pipe and the inner pipe based on the above-mentioned prior art are made of different materials from each other, and the thickness of the inner pipe of a double pipe such as a double pipe is operated with time. In the case where wear occurs due to erosion, the degree of wear tends to be greater when there is an unevenness in the wear site than when there is no unevenness. The technical problem to be solved is to solve the problem of thickness measurement for predicting and estimating the quality of the film. It is possible to measure the degree and to estimate the life of the piping function, and also to maintain the original function of the piping sufficiently, so that the piping technology can be used in various industries. Extract and reduce the thinned part of double pipe made of dissimilar material It is intended to provide a method for measuring the thickness of a meat portion.

<Means and Actions for Solving the Problems> In order to solve the above-mentioned problems, the configuration of the invention of the present application, which is based on the above-mentioned claims, is an inner pipe once installed and installed at a site or the like. Is made of ceramics, etc., and the outer tube is made of a dissimilar material such as a double tube made of metal, etc. Detects flaws such as wear by measuring the change in wall thickness, and irradiates X-rays and other radiation in a direction perpendicular to the surface of the double-walled tube when estimating the possibility of continuous operation while maintaining the function. Then, the thinned portion of the worn portion of the wall thickness is extracted, and then the wall surface of the worn portion is irradiated with the radiation from the direction along the pipe wall to measure the wall thickness. For the measurement on the wall, the irradiated radiation is received on a film, etc. A technical measure has been taken to visually and electrically measure the lightness and to easily and surely estimate the degree of the functional maintenance of the double pipe over time.

<Example> Next, an example of the invention of this application will be described with reference to FIGS. 1, 2, and 3 according to FIGS.

The embodiment shown in FIGS. 1 and 2 is a basic aspect of the invention of this application, and the double pipe 6 as a double pipe shown in FIGS. 3 and 4 is a unit pipe of a predetermined length of a straight pipe. The outer tube 3 as the outer tube is made of carbon steel, and the inner tube 5 as the inner tube made of ceramics is embedded and integrated with the inside thereof through the intermediate layer 4 of cement. The outer tube 3 controls heat resistance and pressure resistance, while the inner tube 5 controls wear resistance and corrosion resistance. (A, b) is installed as a unit pipe of a predetermined length, and X-rays as radiation are used to reduce the thickness of the general inner part (c) of the inner pipe (5) caused by wear of the inner pipe (5) due to the operation over time. And easily and reliably estimate the length of time that the aging function is maintained during the measurement. It is to be able to deal with a given by.

Thus, the X-ray 8 is irradiated from a focal point 7 of an appropriate radiation generating and irradiating device (not shown) in a direction substantially perpendicular to the tube surface.
The film 9 is mounted on the double tube 6 (outer tube 3) in a line-contact manner, receives the irradiated X-rays 8, and measures the density distribution of the photographed image. But,
As a first step, as shown in FIG. 1, irradiation of X-rays 8 from a focus 7 in a direction perpendicular to the tube surface is performed on the tube surface of the inner tube 5 through a predetermined stop, and When the X-ray 8 transmitted through the surface 5 is photographed by the film 9, the density of the density is formed by the thickness of the inner tube 5, and the thickness of the inner tube 5 through which the X-ray 8 is transmitted at the relevant portion. Is different from the thickness (distance L) from the center of the double-walled tube 6, the concentration distribution is appropriately corrected by appropriate mathematical processing (possible with basic mathematical means), and the concentration distribution is corrected. Measure and measure the loss of thickness over time due to pipe operation to detect and extract the reduced thickness portion of the wear, and then, as shown in FIG. 2, the extraction site where the reduced thickness portion was detected From the center of the double tube 6 to the lateral portion parallel to the film 9 to displace the position and posture,
X-rays 8 are radiated as radiation from the focal point 7 in a direction substantially along the thinned portion of the wear through the thick portion, that is, through the wall of the tube, and the thickness of the thinned portion of the wear is formed on the film 9. Then, the change in density of the photographed image is measured to measure the degree of wall thinning of the wear, and the function maintenance time as a double pipe after the measurement timing is estimated from accumulated data and the like.

The above-described embodiment is an embodiment in which the double pipe 6 is a straight pipe. However, as shown in FIG. 5, in the case of a curved pipe 6 ', the film 9' is in the state of the pipe surface of the curved pipe. The measurement is performed by bending the plane posture along the line and making line contact.

The data obtained in this way has the characteristics of the characteristic graph as shown in FIG. 6, and the wall thickness of the inner tube 5 is measured using this.

Thus, in accordance with the mode of the above-described basic embodiment, the measurement positions of the flanges 1 and 2 (a, b) at both ends of the double tube with flange 6 shown in FIG. X-ray 8
Table 2 shows the results of the measurement of the wall thickness through irradiation of the X-rays 8 by the near focus method.

As shown in the data of Table 2, X of the invention of this application
The measurement by the wall thickness measurement by irradiating the line radiation 8 is performed not only for the outer tube 3 but also for the intermediate material 4 of the intermediate layer and also for the ceramic inner tube as the inner tube 5. The measurement effect is different from the data of the prior art in Table 1 in which the thickness measurement was performed and the thickness measurement was performed only on the outer tube 3. It can be seen that the accuracy is almost the same as in the case of the above, and from this point it can be seen that the reliability of the measurement of the measurement data for the outer tube 3, the intermediate layer 4, and the inner tube 5 is high.

Then, the concentration distribution of these data is compared with, for example, measurement data obtained by measuring the wall thickness of the outer tube 3 and the inner tube 5 of the same circular double tube immediately after manufacturing by X-ray 8. The function maintenance data accumulated by comparing the concentration distributions is used to measure the life of the double pipe 6 as the function maintenance state after the measurement, and it is possible to easily estimate the timing of predetermined replacement, maintenance and maintenance, etc. As a result, an unexpected situation can be prevented, and the piping function can be maintained with high efficiency and economic effects.

It should be noted that the embodiments of the invention of this application are not limited to the above-described embodiments. For example, measurement by measuring the density distribution state of imaging of an image received on a film of radiation irradiated from a direction perpendicular to the tube surface is performed. In addition to visual inspection, the density distribution of the film is analyzed and analyzed electronically via an image sensor, etc., converted to data and displayed digitally, displayed on a CRT, etc. For example, various modes, such as displaying on a display, can be adopted.

The radiation is not limited to X-rays, but may be gamma rays.

Of course, the dissimilar material of the double tube can be applied not only to ceramics but also to plastics and other new materials.

<Effects of the Invention> As described above, according to the invention of this application, the outer pipe is basically a steel pipe and controls heat resistance, pressure resistance, etc., and the inner pipe is made of ceramics or the like to control wear resistance and corrosion resistance. Thickness changes such as wall thinning due to wear and the like of the inner pipe of the double pipe where the outer pipe and the inner pipe such as the double pipe are made of different materials, When it is desired to measure the long-term life in a function-maintained state, the thickness of the inner tube is measured using radiation such as X-rays from the direction perpendicular to the tube surface and from the direction along the tube surface. It is possible to estimate the function maintenance time after the measurement and not only has the effect of being able to prepare for an unexpected situation, but also to obtain an image obtained by receiving the radiation such as X-rays on the film. Can directly measure and measure the concentration distribution of The circuit and the like are not required, and the on-site measurement and measurement can be performed while the piping is installed on the site, which has an effect that the operability is extremely good and the cost can be reduced. .

Therefore, in the invention of this application, irradiation of X-rays or the like from a direction perpendicular to the tube surface is first performed on the tube surface of the double-walled tube to generate a thinned portion of the inner tube or the like in a worn state. Detecting and extracting the portion, and then irradiating the wall portion of the detected extraction site with radiation from the direction along the tube surface to the thinned portion to accurately determine the thickness of the inner tube. It can be measured by measuring the density distribution of the photographing of the received image.Thus, not only the worn part of the inner tube etc. but also the thinning such as dents and dents are spot-like and linear, qualitatively and quantitatively. This is an excellent effect that the life of the double-walled pipe made of dissimilar material, such as the number of years of function maintenance, can be reliably measured in this state.

Such a qualitative position of the worn state of the inner tube of the double-walled tube and the detection by measurement of the quantitatively worn-out state have an effect of reliably adding to the function measurement of the double-walled tube.

Further, the thickness measurement method of the invention of this application does not use a special measurement device or the like, and can be performed by artificial and empirical work, so that on-site measurement can be easily performed even on a complicated piping such as a plant. There is also an effect.

[Brief description of the drawings]

The drawings are explanatory views of the embodiments of the invention of the present application.
FIG. 2 is a view showing an embodiment of the principle aspect, and FIG.
FIG. 2 is a sectional view of the X-ray irradiation in a direction along the pipe wall of the double pipe, FIG. 3 is a partially cutaway perspective view of the double pipe, FIG. 4 is a side view of the double pipe in a straight pipe state, FIG. FIG. 5 is a side view of a curved pipe state, and FIG.
The figure is a graph of measurement and measurement. 3 ... Outer tube, 5 ... Inner tube 6 ... Double tube, 8 ... Radiation 9 ... Film

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-269008 (JP, A) JP-A-54-114263 (JP, A)

Claims (4)

(57) [Claims] An outer pipe and an inner pipe are made of dissimilar materials, and the thickness of the inner pipe is measured by photographing with radiation irradiation. In the method of measuring the thickness of the wall portion, first, a wall surface portion for measuring the wall thickness is irradiated with radiation from a direction perpendicular to the wall surface to extract a wall-thinned portion, and then the wall portion of the wall portion is measured for the wall-thickness portion. A method for extracting a thinned portion of a double-walled pipe made of dissimilar material and measuring the thickness of the thinned portion, wherein the thickness is measured by irradiating radiation from a direction along the line. 2. The method according to claim 1, wherein said measurement is carried out by film image reception. how to. 3. The method according to claim 1, wherein the radiation is performed as X-rays, and the thickness of the reduced thickness portion is measured and the thickness of the reduced thickness portion is measured. how to. 4. The method according to claim 1, wherein the measurement is performed by measuring the density distribution of a plane image of the film. A method for measuring the thickness of a part.