Nondestructive inspection method and nondestructive inspection device

Abstract

To provide a nondestructive inspection method and a nondestructive inspection device with which it is possible to measure the thickness reduction of a structure or the height of a deposit deposited inside the structure with better accuracy than conventional methods.SOLUTION: Provided is a nondestructive inspection method for measuring the thickness reduction of a structure or the height of a deposit deposited inside the structure by using a radiation transmission method. This inspection method includes: a transit dose measurement step (step S1) for scanning a sensor and measuring a transit dose (count Cn) having passed through the structure; and a height calculation step (step S4) for calculating a thickness reduction Δt of the structure or a height Δt of a deposit deposited inside the structure by using the transit dose (count Cn) at a measurement point and the transit dose (count C0) at a reference point given by a reference part estimation curve obtained by regressively analyzing the transit dose (count Cn) at the measurement point.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and device for measuring the amount of thinning of structures such as pipes (including coated pipes) and towers and vessels, and the height of deposits inside the pipes, and more particularly to a non-destructive inspection method and device using a radiographic method. [Background technology]

[0002] In large plants, the total length of coated pipes is enormous, amounting to tens of kilometers, so it is necessary to screen without dismantling the coating and narrow down the area that requires secondary inspection after dismantling the coating. The radiographic method is an excellent screening method that allows visual understanding of the thinning condition of coated pipes without dismantling the coating.

[0003] Among the radiographic methods, the planar radiography method evaluates the shading of the image caused by differences in the transmitted thickness, and can grasp the thinning condition over a wider area than the edge radiography method. In the planar radiography method, the radiation source and sensor are scanned together along a straight pipe to measure the amount of thinning. With this method, data analysis is relatively easy because the geometric arrangement of the radiation source, sensor, and object to be inspected remains unchanged.

[0004] When measuring the amount of thinning near the weld between a straight pipe and an elbow or on the back side of an elbow, it is not possible to use an integrated device that scans the radiation source and sensor together. In such cases, it is necessary to use a fixed device in which the radiation source is fixed and only the sensor scans (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-63789 Summary of the Invention [Problem to be solved by the invention]

[0006] Inspection methods using fixed equipment require a different data analysis method than inspection methods using integrated equipment because the geometric arrangement of the radiation source, sensor, and inspection target changes from moment to moment. In theory, the amount of thinning can be calculated by preparing a comparison test piece with the same piping specifications (outer diameter, thickness, material) as the inspection target piping and comparing the transmitted radiation dose (number of counts) of both.

[0007] When photographing a comparison test piece, it is necessary to reproduce the actual photographing conditions in terms of the photographing arrangement and the radiation transmission path from the radiation source to the sensor. In particular, the photographing arrangement and the fluid in the pipe have a large effect on the measurement results, but since it is not possible to faithfully reproduce these, it is not realistic to measure wall thinning using a comparison test piece.

[0008] An object of the present invention is to provide a non-destructive inspection method and a non-destructive inspection device that can measure the amount of wall thinning of a structure or the height of deposits accumulated inside the structure with greater accuracy than conventional methods. [Means for solving the problem]

[0009] The present invention is a non-destructive inspection method for measuring the amount of thinning of a structure or the height of deposits accumulated inside the structure by using a radiological transmission method, and the amount of radiation (count number C n ) and the transmission dose measurement step, which measures the transmission dose at the measurement point (count number C n ) and the transmitted dose at the measurement point (count number C n ) and the transmitted dose (count number C0) of the reference point given by the reference part estimation curve obtained by regression analysis of the reference part estimation curve, and a height calculation step of calculating the amount of wall thinning Δt of the structure or the height Δt of the deposits deposited inside the structure by formula (4); The non-destructive inspection method is characterized by having the following features. Δt=ln(C n / C0) / μ (4) where C n : Number of counts at the measurement point (transmitted radiation amount) C0: Number of counts at the reference point (transmitted dose) Δt: Amount of thinning or height of deposit (mm) μ: Linear attenuation coefficient of the pipe (mm -1 ) For deposit measurements, the linear attenuation coefficient of the deposit (mm -1 )

[0010] In the non-destructive inspection method according to the present invention, the reference portion estimation curve is a transmission dose (count number C n ) and calculates it by performing regression analysis on the data of healthy sections.

[0011] In the non-destructive inspection method according to the present invention, the reference portion estimation curve is a transmission dose (count number C n ) to calculate a provisional reference part estimated curve; and calculating a transmission dose (count number C0') of the provisional reference point given from the provisional reference part estimated curve and a transmission dose (count number C n ) and the transmitted dose (count number C n A masking data selection step of selecting data to be masked from the masked data, and a transmission dose (count number C n and a reference portion estimated curve calculation step of calculating the reference portion estimated curve by performing regression analysis on the reference portion estimated curve.

[0012] The non-destructive inspection method according to the present invention further includes a linear attenuation coefficient acquisition step of acquiring a linear attenuation coefficient μ, and the linear attenuation coefficient acquisition step includes placing a test piece having a known thickness t0 between a radiation source and the sensor, scanning the sensor, and measuring the amount of radiation (count number C nt0 ) and a test piece transmission dose measurement step for measuring the transmission dose (count number C n ) and the transmitted dose (count number C nt0) to calculate the linear attenuation coefficient μ by equation (6), and wherein in the test piece transmission dose measurement step, when measuring the amount of thinning Δt of the structure, a test piece made of the same material as the structure is used, and when measuring the height Δt of the deposit deposited inside the structure, a test piece made of the same material as the deposit is used. μ = ln(C n / C nt0 ) / t0····(6) where C n : Number of counts at the measurement point that penetrated the structure (transmitted dose) C nt0 : Number of counts at the measurement point through the structure and test piece (Transmitted dose) t0: thickness of test piece (mm) μ: Linear attenuation coefficient of the pipe (mm -1 ) For deposit measurements, the linear attenuation coefficient of the deposit (mm -1 )

[0013] The non-destructive inspection method according to the present invention is characterized in that, in the test piece transmission dose measuring step, the test piece is attached or placed on the sensor.

[0014] In the non-destructive inspection method according to the present invention, the radiation source that irradiates radiation to the structure being inspected is a fixed type, an integrated type that moves integrally with the sensor, or a synchronous type that moves in synchronization with the sensor.

[0015] The present invention is a non-destructive inspection method characterized by comprising a screening step of using the non-destructive inspection method to select areas of thinning or deposition in the structure.

[0016] The present invention is a non-destructive inspection method comprising: a screening process for selecting areas of thinning in the structure using the non-destructive inspection method; and a wall thickness measurement process for measuring the areas of thinning with an ultrasonic thickness gauge.

[0017] The present invention is a data processing device for a non-destructive inspection device that uses a radiation transmission method to measure the amount of thinning of a structure or the height of deposits accumulated inside the structure, and the amount of radiation (count number C n ), and a means for calculating a reference portion estimated curve by performing regression analysis on the calculated reference portion estimated curve; n and a height calculation means for calculating the amount of wall thinning Δt of the structure or the height Δt of the deposit deposited inside the structure by using the reference point (count number C0) and the reference point estimated curve (count number C0) given by the reference portion estimation curve according to equation (4). Δt=ln(C n / C0) / μ (4) where C n : Number of counts at the measurement point (transmitted radiation amount) C0: Number of counts at the reference point (transmitted dose) Δt: Amount of thinning or height of deposit (mm) μ: Linear attenuation coefficient of the pipe (mm -1 ) For deposit measurements, the linear attenuation coefficient of the deposit (mm -1 )

[0018] The present invention is a non-destructive inspection apparatus comprising the data processing device, a radiation source which irradiates a structure which is an inspection target with radiation, a sensor which detects the amount of radiation which has passed through the structure, and moving means for moving the sensor, or the radiation source and the sensor, wherein the radiation source and the sensor are of a fixed type in which the radiation source is fixed and the sensor moves, an integrated type in which the radiation source moves integrally with the sensor, or a synchronous type in which the radiation source moves in synchronization with the sensor.

[0019] In the non-destructive inspection device according to the present invention, the sensor is a line sensor.

[0020] The present invention is a program for causing a computer to function as the data processing device. Effect of the Invention

[0021] According to the present invention, it is possible to provide a non-destructive inspection method and a non-destructive inspection device that can measure the amount of wall thinning of a structure or the height of deposits accumulated inside the structure with greater accuracy than conventional methods. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a flow chart showing the procedure of a nondestructive inspection method according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining the relationship between an imaging arrangement and a transmitted radiation amount, which forms the basis of the nondestructive inspection method according to the first embodiment of the present invention. [Diagram 3] FIG. 1 is a diagram for explaining the nondestructive inspection method according to the first embodiment of the present invention, showing a sample in which a coated pipe was photographed and a wall thinning evaluation was performed. [Figure 4] FIG. 2 is a diagram for explaining the configuration of a nondestructive inspection device 1 according to a second embodiment of the present invention. [Diagram 5] FIG. 2 is a diagram showing a method for measuring the amount of metal loss and the results in Example 1 of the present invention. [Figure 6] FIG. 11 is a diagram showing a method for measuring the amount of metal loss and the results in Example 2 of the present invention. [Figure 7] FIG. 11 is a diagram showing a method for measuring the state of a fireproof material in Example 3 of the present invention. [Figure 8] 13 is a diagram for explaining a method for measuring the deposit height or water resistance in a pipe in Example 4 of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Fig. 1 is a flow diagram showing the procedure of the nondestructive inspection method of the first embodiment of the present invention. Fig. 2 is a diagram for explaining the radiation source intensity distribution which is the basis of the nondestructive inspection method of the first embodiment of the present invention. Fig. 3 is a diagram for explaining the nondestructive inspection method of the first embodiment of the present invention, showing a sample in which a radiation source is fixed, a line sensor is scanned to photograph a coated pipe, and wall thinning evaluation is performed.

[0024] The non-destructive inspection method of the first embodiment of the present invention uses a radiographic method to measure the amount of thinning of a structure to be inspected or the height of deposits accumulated inside the structure. The structures to be inspected include individual objects such as pipes and towers and vessels, as well as pipe bodies and towers and vessels that are covered with heat-insulating materials, heat insulating materials, and heat-insulating sheet metal. Pipes also include straight pipes, bent pipes, elbows, reducers, and connections of these.

[0025] Prior to describing the procedure of the nondestructive inspection method according to the first embodiment of the present invention, the relationship between the amount of thinning Δt and the transmitted radiation I will be described.

[0026] The rate of change, ΔI / I0, of the transmitted dose of radiation irradiated from a radiation source and transmitted through a test piece is proportional to the change in thickness, Δt, of the test piece, and equation (1) is established. ΔI / I0=-μΔt (1) Here, I0: Penetration dose passing through the test piece μ: proportionality constant (linear attenuation coefficient) ΔI / I0: Rate of change of transmitted radiation Δt: Change in thickness of test piece

[0027] If the amount of thinning is Δt and the amount of radiation passing through the thinned part of the test piece is I1, equation (2) can be obtained from equation (1). I1 / I0 = exp(μΔt) (2)

[0028] When the transmitted dose is detected by a sensor, the sensor provides a count number C corresponding to the transmitted dose. If the transmitted dose I = count number C, then equation (3) can be obtained from equation (2). ln(C1 / C0)=μ Δt (3) Where C0: The number of counts corresponding to the radiation transmitted through the healthy part of the test piece C1: The number of counts corresponding to the radiation transmitted through the thinned part of the test piece

[0029] In the non-destructive inspection method according to the first embodiment of the present invention, the amount of wall thinning Δt of a structure or the height Δt of deposits inside the structure is calculated using formula (3). The deposits inside the structure include water. A specific calculation method will be described below. Here, a fixed device with a fixed radiation source and a scanning sensor is used to calculate the amount of wall thinning Δt of a structure or the height Δt of deposits.

[0030] The radiation source and the sensor are placed facing each other with the structure to be inspected in between, and the amount of radiation penetrating the structure (count number C n ) is measured (step S1). The measured count number C n and the count number C0 at the reference point, the amount of wall thinning Δt of the structure or the height Δt of the deposits inside the structure is calculated by equation (4) (step S4). Δt=ln(C n / C0) / μ (4) where C n : Number of counts at the measurement point (transmitted radiation amount) C0: Number of counts at the reference point (transmitted dose) Δt: Amount of thinning or height of deposit (mm) μ: Linear attenuation coefficient of the pipe (mm -1 ) For deposit measurements, the linear attenuation coefficient of the deposit (mm -1 )

[0031] The amount of wall thinning Δt of a structure obtained by the nondestructive inspection method of the first embodiment of the present invention is the amount of wall thinning (relative amount of wall thinning) relative to the surrounding area that is free of wall thinning and can be considered sound. Similarly, the height of deposits Δt inside a structure obtained by the nondestructive inspection method of the first embodiment of the present invention is the height of deposits relative to the surrounding area that is free of deposits.

[0032] Here, the count number C0 at the reference point will be explained. In calculating the amount of wall thinning Δt of a structure or the height of deposits Δt, the transmitted radiation amount (count number C0) at the reference point is the transmitted radiation amount (count number) that penetrates a portion without wall thinning (sound portion) in calculating the amount of wall thinning Δt, and is the transmitted radiation amount (count number) that penetrates a portion without deposits (sound portion) in calculating the height of deposits Δt inside the structure.

[0033] Fig. 2 is a diagram for explaining the radiation source intensity distribution, Fig. 2(A) shows the positional relationship between the X-ray source, the pipe, and the line sensor, and Fig. 2(B) shows the relationship between the line sensor position and the transmitted dose (number of counts) when the X-ray source is fixed and the line sensor is scanned along a straight pipe. The parameter is the distance L on the central axis from the X-ray source to the line sensor.

[0034] As shown in Figure 2, the number of counts received by the line sensor on the central axis increases as the distance L between the X-ray source and the line sensor decreases. When the X-ray source is fixed and the line sensor is scanned, the geometric arrangement of the piping and the line sensor relative to the X-ray source changes, so the intensity of the radiation source varies depending on the position of the sensor. As the line sensor moves away from the central axis in the left-right direction (X direction), the number of counts received by the line sensor decreases, and the rate of decrease increases as the distance L decreases.

[0035] As described above, when the radiation source is fixed and the sensor is scanned, the geometric arrangement of the structure and the sensor relative to the radiation source changes, and it is clear that the radiation source intensity varies depending on the sensor position. Therefore, when calculating the amount of thinning of the structure Δt or the height of deposits inside the structure Δt by fixing the radiation source and scanning the sensor, it is necessary to calculate the count number C0 at the reference point taking into account the radiation source intensity distribution.

[0036] In the case of an integrated type in which the radiation source and the sensor are scanned integrally with respect to the straight pipe, the geometric arrangement of the radiation source, the sensor, and the straight pipe is generally constant, so the transmitted dose (count number C0) is constant. However, when the coating material is misaligned with the pipe, the geometric arrangement of the radiation source, the sensor, and the straight pipe changes when the radiation source and the sensor are scanned integrally along the coating material, so the transmitted dose (count number C0) is not constant (see Example 2 described later).

[0037] As described above, when the geometric arrangement of the radiation source, the sensor, and the object to be inspected changes, the transmitted dose (count number C0) does not become a constant value even if the thickness of the object to be inspected is the same. For this reason, in this embodiment, a correlation equation between the measurement position and the transmitted dose (count number C0) of the healthy part at that position is obtained, and the count number C0 at the reference point of each measurement position given by the correlation equation is used to calculate the amount of wall thinning Δt or the height Δt of the deposit inside the structure.

[0038] In this embodiment, the correlation equation between the measurement position (measurement point) and the transmitted dose (count number C0) of the healthy part at that position is called the reference part estimation curve. As described above, the reference part estimation curve is a continuous line of reference points at each measurement position (see FIG. 3(B)). The calculation method of the reference part estimation curve will be described below.

[0039] The reference portion estimation curve is the count number C at each measurement point obtained by scanning the sensor in step S1. n The count number C at all measurement points is calculated by regression analysis (step S2). n The number of counts C of areas other than healthy parts, such as thinned parts or welded parts, is n In order to obtain a standard part estimation curve with less error, the count number C in the healthy part excluding the thinned part, welded part, etc. n It is necessary to calculate the reference section estimated curve using

[0040] Count number C at thinned and welded parts n is the number of counts in the surrounding healthy area, C n(See Fig. 3(B)). Therefore, the count number C n Of these, the number of counts in the surrounding healthy areas is C n By masking the counts that fluctuate significantly compared to the above (hereinafter referred to as "outliers") and performing regression analysis on these, the counts C of healthy areas excluding thinned areas, welded areas, etc. are obtained. n It is possible to calculate the reference section estimated curve using the above formula.

[0041] A method for mechanically masking outliers is explained. First, the counts C n A provisional reference portion estimated curve is calculated by regression analysis using the above (step S2-1). Next, the count number C0' at the reference point given from the provisional reference portion estimated curve and the count number C0 at the measurement point are calculated. n Using this, Δt´·μ at each measurement point is calculated using equation (5). Δt´·μ=ln(C n / C0´)····(5) where C n : Number of counts at the measurement point (transmitted radiation amount) C0´: The number of counts at the reference point given by the provisional reference section estimated curve (Transmission dose) Δt´: In the case of pipe thinning measurement, the change in pipe thickness (mm) : For deposit measurements, the height of the deposit (mm) μ: Linear attenuation coefficient of the pipe (mm -1 ) For deposit measurements, the linear attenuation coefficient of the deposit (mm -1 )

[0042] An outlier is selected from the obtained Δt′·μ and a predetermined threshold S (step S2-2). The count number (transmitted dose) at the measurement point of Δt′·μ that exceeds the threshold S is set as the outlier. The outlier is masked and the count number C at the remaining measurement points is set as the outlier. n' is used as healthy section data, and regression analysis is performed again to calculate the reference section estimated curve (step S2-3). If it is desired to improve accuracy, the obtained reference section estimated curve is used as a tentative reference section estimated curve, and steps S2-1 to S2-3 may be repeated multiple times.

[0043] Since the nondestructive inspection method of this embodiment is basically positioned as screening for detecting thinning areas or deposit areas of a structure, masking in the calculation of the reference portion estimated curve only needs to be performed once.

[0044] When the number of thinned parts, welded parts, etc. is overwhelmingly smaller than the number of healthy parts, the count number C at all measurement points including thinned parts and welded parts is n The provisional standard part estimated curve calculated using the above and the count number C of only the healthy part excluding the thinned part and welded part n There is almost no difference between the estimated curve of the reference part calculated using the '. Therefore, in a simple case, the count number C at all measurement points is n Alternatively, a provisional reference portion estimated curve obtained by performing regression analysis on the above may be used as the reference portion estimated curve.

[0045] Next, a method for calculating the linear attenuation coefficient μ will be described (step S3). With a test piece made of the same material as the object to be inspected and having a known thickness t0 placed or attached to the sensor body, the amount of radiation transmitted through the structure (count number C nt0 ) is measured (step S3-1). Therefore, when measuring the amount of wall thinning Δt of a structure, a test piece made of the same material as the structure is used, and when measuring the height Δt of deposits accumulated inside the structure, a test piece made of the same material as the deposits is used.

[0046] The transmitted dose (count number C) of the structure measured without using a test piece n ) and the resulting count number C nt0 Using these values, μ is calculated according to equation (6), and the average value is set as the linear attenuation coefficient μ (step S3-2). μ = ln(C n / C nt0 ) / t0····(6) where C n: Number of counts at the measurement point that penetrated the structure (transmitted dose) C nt0 : Number of counts at the measurement point through the structure and test piece (Transmitted dose) t o : thickness of test piece (mm) μ: Linear attenuation coefficient of the pipe (mm -1 ) For deposit measurements, the linear attenuation coefficient of the deposit (mm -1 )

[0047] In calculating the linear attenuation coefficient μ, the transmitted radiation (count number C nt0 When measuring the radiation intensity, the test piece may be located between the radiation source and the sensor. Although the test piece may be attached to the structure to be inspected, the method of placing or attaching the test piece to the sensor body is simple and preferable.

[0048] Using multiple test pieces with different thicknesses t0, the transmitted dose C nt0 or by using a stepped test piece whose thickness changes stepwise, the transmitted dose C nt0 By measuring this, the linear attenuation coefficient μ can be calculated with high accuracy.

[0049] In the case of measuring the amount of thinning by dividing the section into sections A, B, and C as in the second embodiment shown in FIG. 4, the transmitted radiation (count number C nt0 ) and calculate the linear attenuation coefficient μ, it is not necessary to calculate the linear attenuation coefficient μ in other sections.

[0050] FIG. 3 shows a sample in which a coated pipe was photographed and subjected to a wall thinning evaluation using the non-destructive inspection method of the first embodiment of the present invention. Here, a radiation source was fixed and a line sensor was scanned to photograph the coated pipe. FIG. 3(A) shows a photographed image, with the horizontal axis representing the scanning distance of the line sensor and the vertical axis representing the channel number of the line sensor. FIG. 3(B) shows data from channel 38 of the line sensor, with the horizontal axis representing the scanning distance of the sensor and the vertical axis representing the transmitted radiation (number of counts C n) and also shows the reference section estimation curve. Figure 3(C) shows the measurement results for channel 38 of the line sensor, with the horizontal axis being the sensor scanning distance and the vertical axis being the relative amount of thinning Δt. The d in the maximum thinning section (2.1d) in Figure 3(C) represents the depth in mm. Therefore, 2.1d represents 2.1 mm.

[0051] As described above, the non-destructive inspection method of the present invention introduces a reference part estimation curve and calculates the amount of wall thinning of the structure or the height Δt of the deposits accumulated inside the structure from the transmitted dose at each measurement point and the transmitted dose at the reference point given by the reference part estimation curve. Therefore, even if the geometric arrangement of the radiation source, sensor, and structure changes and the radiation source intensity differs depending on the measurement position, it is possible to calculate the amount of wall thinning of the structure or the height of the deposits accumulated inside the structure with greater accuracy than conventional methods.

[0052] The non-destructive inspection method according to the present invention, which has the above-mentioned characteristics, is not limited to the scanning direction of the sensor in the longitudinal direction of the pipe, and can measure wall thinning in the circumferential direction of the pipe, which was difficult to measure with the conventional method. It can also measure wall thinning in structures that cannot be photographed in the longitudinal direction, such as elbows, reducers, and the vicinity of welds between straight pipes and elbows, which was difficult to measure with the conventional method.

[0053] The non-destructive testing method of the present invention, when measuring the amount of wall thinning Δt of a straight pipe coated with a coating material using an integrated device that scans a radiation source and a sensor together, or a synchronous device that scans a radiation source and a sensor in synchronization, can calculate the amount of wall thinning of the straight pipe more accurately than conventional methods even if the coating material is misaligned with the piping.

[0054] Furthermore, the nondestructive testing method of the present invention does not use a comparative test method in which a comparison test piece having the same piping specifications (outer diameter, thickness, material) as the piping to be inspected is prepared and the amount of wall thinning is calculated from the transmitted radiation dose (count number) between the two. Therefore, the method can be suitably used for measuring the amount of wall thinning, amount of deposits, amount of retained water, and deterioration and spalling of refractory materials in piping, towers, and tanks of equipment in operation.

[0055] 4 is a diagram for explaining the configuration of a nondestructive inspection device 1 according to a second embodiment of the present invention. In this embodiment, a pipe 101 is an object to be inspected, and is a pipe having a pipe body 105 provided with a heat-insulating material 106 and a heat-insulating metal plate 107, and the pipe axis x of the pipe is arranged horizontally (parallel to the X-axis).

[0056] In this embodiment, the pipe 101 to be inspected is covered with a heat insulating material or the like, but the pipe 101 to be inspected may be a pipe consisting of only the pipe body. The X-direction, Y-direction, and Z-direction described in the drawings and the specification respectively represent the X-axis direction, the Y-axis direction, and the Z-axis direction of a three-dimensional orthogonal coordinate system. The axial direction is a direction parallel to the pipe axis x, the radial direction is a direction perpendicular to the pipe axis y, and the circumferential direction is a direction along an arc centered on the pipe axis y.

[0057] The non-destructive inspection device 1 of this embodiment is roughly divided into a screening device 2 that detects thinning portions of a pipe 101 and an ultrasonic thickness meter 70 that measures the thickness of the thinning portions detected by the screening device 2.

[0058] The screening device 2 comprises a radiation source 10 that irradiates radiation onto the pipe 101, a sensor 20 that detects the amount of radiation passing through the pipe 101, a traveling means 30 that travels the sensor 20 along the pipe 101, and a data processing device 50.

[0059] Radiation source 10 is not particularly limited, and can be appropriately selected and used from among those suitable for inspecting pipe 101. Sensor 20 is also not particularly limited, and can be appropriately selected and used from among those suitable for inspecting pipe 101, such as a line sensor. A line sensor is a sensor in which multiple elements are arranged in a straight line.

[0060] The traveling means 30 includes a traveling rail 31, a traveling carriage 38, and a drive device 40 that moves the traveling carriage 38. The traveling rail 31 includes a pair of guide rails 32 on which the traveling carriage 38 travels, and a belt 34 that connects the guide rails 32, and the guide rails 32 are fixed to the left and right (Z direction) of the belt 34 via mounting fixtures 36. The belt 34 is made of a rubber material and has flexibility, and comes into contact with the outer circumferential surface (outer wall surface) of the pipe 101 to prevent the traveling rail 31 from slipping.

[0061] The traveling rail 31 may be fixed to the piping 101 using a fixing belt such as a lashing belt. If a fixing belt such as a lashing belt is used, it becomes possible to inspect the traveling rail 31 in an oblique direction with respect to the piping 101, for example, at 30° or 60° with respect to the vertical axis (Z axis).

[0062] The traveling cart 38 has wheels, is equipped with the sensor 20, and travels on the traveling rail 31. The structure and shape of the traveling cart 38 are not particularly limited as long as the traveling cart 38 can securely fix the sensor 20 and can stably travel on the traveling rail 31 with the sensor 20 mounted thereon.

[0063] The driving device 40 is mainly composed of a wire winder 42, which connects a wire 43 to the traveling cart 38 and moves the traveling cart 38 by winding up the wire 43. The wire winder 42 is equipped with a speed controller and a distance encoder 45, and is capable of adjusting the winding speed of the wire 43 and detecting the amount of the wire 43 wound.

[0064] The traveling means 30 is not limited to the above embodiment, and may be any means capable of stably traveling the sensor 20 along the pipe 101.

[0065] The data processing device 50 includes data input means 51, data output means 52, storage means 53, control means 54, and wall-thinning amount calculation means 55, and is connected to the radiation source 10, the sensor 20, and the drive device 40 to control these devices and acquire captured image data. The wall-thinning amount calculation means 55 includes reference portion estimated curve calculation means 56 and height calculation means 57. The data processing device 50 is equipped with a program for executing the nondestructive inspection method of the first embodiment, and the wall-thinning amount calculation means 55 calculates the wall-thinning amount based on the program.

[0066] The ultrasonic thickness gauge 70 includes a main body 71 equipped with a display unit 73 and an operation unit 74, and a probe 75, and measures the thickness of the thinning area detected by the screening device 2. The ultrasonic thickness gauge 70 is connected to the data processing device 50 of the screening device 2, and transmits the measurement data to the data processing device 50. The ultrasonic thickness gauge 70 used here is not particularly limited, and any known ultrasonic thickness gauge can be used.

[0067] An inspection method using the nondestructive inspection device 1 of this embodiment will be described. Here, the pipe 101 to be inspected is divided into a plurality of sections, and inspection is performed while sequentially changing the section. Specifically, the inspection section of the pipe 101 is divided into three sections: section A, section B, and section C. The sections are divided by placing lead marks 150 at the boundaries between the sections. Also, lead marks 151 are placed in the center of each section. Lead marks 150 are attached to the upper outer wall of the pipe 101, and lead marks 151 are attached to the bottom outer wall of the pipe 101.

[0068] When inspecting the pipe 101 to be inspected, first, the radiation source 10 is installed at the center (X direction) of section A, and the sensor 20 is caused to travel within section A via the traveling means 30 to inspect section A. The radiation source 10 is installed using the lead mark 151 as a landmark, and the travel section is determined using the lead mark 150 as a landmark. Next, the radiation source 10 is installed at the center (Y direction) of section B, and the sensor 20 is caused to travel within section B via the traveling means 30 to inspect section B. Section C is also inspected in a similar manner.

[0069] The length of the inspection section is determined taking into consideration the specifications of the radiation source 10, the sensor 20, and the piping 101, as well as the change in radiation source intensity based on the geometric arrangement of the radiation source 10, the sensor 20, and the piping 101.

[0070] If a thinning area is detected by the screening device 2 (screening process), the heat-insulating sheet metal and heat-insulating material at the relevant area are removed, and the wall thickness is measured using an ultrasonic thickness gauge 70 (wall thickness measurement process).

[0071] The configuration of the nondestructive inspection device 1 according to the second embodiment and the method of using the device have been described above, but the configuration of the nondestructive inspection device according to the present invention and the method of using the device are not limited to the above embodiment. They can be modified and used within the scope of the gist of the invention.

[0072] In the nondestructive inspection apparatus 1 of the second embodiment, the screening device 2 is a fixed device in which the radiation source 10 is fixed and the sensor 20 is scanned, but instead of the fixed device, it may be an integrated device in which the radiation source 10 and the sensor 20 are scanned integrally, or a synchronous device in which the radiation source 10 and the sensor 20 are scanned in synchronization with each other. In the case of an integrated device or a synchronous device, it is necessary to provide a corresponding traveling means, but the data processing device 50 and the ultrasonic thickness gauge 70 can be the same as those in the nondestructive inspection apparatus 1 of the second embodiment.

[0073] In addition, the non-destructive inspection device 1 of the second embodiment is composed of a screening device 2 that detects areas of thinning in the pipe 101, and an ultrasonic thickness gauge 70 that measures the thickness of the areas of thinning detected by the screening device 2, but the non-destructive inspection device according to the present invention may calculate the amount of thinning using the screening device 2 and omit the ultrasonic thickness gauge 70.

[0074] A preferred non-destructive inspection method, a non-destructive inspection device, and a data processing device have been described with reference to the drawings, but a person skilled in the art will easily imagine various changes and modifications within the obvious scope upon reading this specification. Therefore, such changes and modifications are interpreted as falling within the scope of the invention as defined by the claims. EXAMPLES

[0075] <Example 1> Using the fixed non-destructive inspection device according to the present invention, the amount of thinning near the weld line between a straight pipe and an elbow was measured in the following manner. Figure 5(A) shows the photographing procedure, and Figure 5(B) shows the measurement results. An X-ray source was used as the radiation source. The sensor used was an energy discrimination type radiation line sensor (model number C13247) for pipe thinning inspection manufactured by Hamamatsu Photonics K.K. The detection element dimensions of this line sensor were 3.3 mm x 3.3 mm, the number of detection elements (number of channels) was 64, and the detection width was 211 mm.

[0076] The subject of the imaging was a 650A, Sch.10 coated pipe (φ660.4, thickness 7.9mm), with a mist inside. As shown in Figure 5(A), the X-ray source was fixed, and the line sensor was placed facing the pipe, and the line sensor was run in the circumferential direction to measure the amount of thinning near the weld line between the straight pipe and the elbow. The imaging range was approximately 400mm centered on the pipe axis. The d in the maximum thinning part (2.2d) in Figure 5(A) represents the depth, measured in mm. Therefore, 2.2d represents 2.2mm.

[0077] The photograph on the right side of Fig. 5(B) is a photographed image, and the graph on the left side of Fig. 5(B) is the amount of thinning at the position of the dashed line shown in the photograph on the right side of Fig. 5(B) calculated using the non-destructive inspection method of the first embodiment. The numerical values ​​in the photograph on the right side of Fig. 5(B) are the remaining thickness (mm) measured separately with an ultrasonic thickness gauge after the coating was removed. From this result, it can be seen that there are scattered shadings due to thinning on the straight pipe (carbon steel) side, whereas no significant indication of thinning is observed on the elbow (stainless steel) side.

[0078] The coating was removed from the area around the area with the greatest thinning, and the remaining wall thickness was measured with an ultrasonic thickness gauge, and the two results were compared. In the area where the coating was removed, the paint on the outside of the pipe was sound and no thinning was found on the outside, and all of the thinning indications from the line sensor were for internal wall thinning. Additionally, the results of measuring the remaining wall thickness by sampling from the top of the pipe (the radiation source side) showed no significant thinning. Therefore, all of the thinning indications were from the bottom of the pipe (the line sensor side).

[0079] The remaining wall thickness around the area of ​​maximum thinning was approximately 7.3 mm, and the remaining wall thickness at the area of ​​maximum thinning detected by the line sensor was 4.9 mm. Multiple points were measured around the area, and it was confirmed that this was the minimum remaining wall thickness. Therefore, the maximum thickness thinning evaluated by ultrasonic thickness measurement was 2.4d (=7.3mm-4.9mm). From the above, the screening results by the line sensor and the results of ultrasonic thickness measurement were generally consistent.

[0080] <Example 2> The integrated non-destructive inspection device according to the present invention was used to measure the amount of thinning of coated pipes in the following manner. Ir-192 was used as the radiation source. An energy discrimination type radiation line sensor for pipe thinning inspection (model number C13247) manufactured by Hamamatsu Photonics K.K. was used as the sensor. The detection element dimensions of this line sensor were 3.3 mm x 3.3 mm, the number of detection elements (number of channels) was 64, and the detection width was 211 mm.

[0081] A radiation source was fixed to one side of the frame, a line sensor was fixed to the other side of the frame, a running rail was attached parallel to the covering sheet metal (exterior plate), and the frame with the radiation source and line sensor was run along the running rail to measure the amount of thinning of the covered pipe. The pipe was straight, and the maximum length of each shot was 2m.

[0082] The results are shown in Figure 6. Figure 6(A) shows the captured image, with the horizontal axis representing the scanning distance and the vertical axis representing the line sensor channel number. Figure 6(B) shows data from channel 22 of the line sensor, with the horizontal axis representing the scanning distance and the vertical axis representing the transmitted dose (count number C n ) The reference portion estimation curve in the figure is calculated by the non-destructive inspection method of the first embodiment. Fig. 6(C) shows the measurement result of channel 22 of the line sensor, with the horizontal axis representing the scanning distance and the vertical axis representing the relative amount of thinning Δt.

[0083] From these results, it is evident that the amount of thinning in a coated pipe can be measured using the integrated non-destructive testing device according to the present invention. The reference part estimation curve shown in FIG. 6(B) is a curve sloping downward to the right. This indicates that the axis of the coating sheet metal (exterior plate) is misaligned with the axis of the pipe. Even in such a case, the non-destructive testing method according to the present invention uses the reference part estimation curve to calculate the amount of thinning, so that it is possible to calculate the amount of thinning more accurately than the conventional method.

[0084] <Example 3> Using the fixed non-destructive inspection device according to the present invention, the deterioration state of the fireproofing material was confirmed in the following manner. The shooting arrangement is shown in Fig. 7. The object to be inspected was a vertical gas pipe (outer diameter φ2600 × t12), and a 60 mm thick fireproofing material was installed on the inner surface of the pipe. An X-ray source was used as the radiation source, and an energy discrimination type radiation line sensor for pipe thinning inspection (model number C13247) made by Hamamatsu Photonics K.K. was used as the sensor.

[0085] The X-ray source and the line sensor were placed facing each other across the pipe, and the line sensor was moved up and down to take pictures. The line sensor movement speed was 2.5 mm / sec, accumulation time: 1 sec, and measurement pitch: 2.5 mm. As a result of the measurement, it was found that the fireproofing material had fallen off over a wide area.

[0086] <Example 4> Using the fixed non-destructive inspection device according to the present invention, deposits in butadiene pipes were confirmed in the following manner. The butadiene pipes were 12B x sch30 (t8.4) and had no coating material. An X-ray source was used as the radiation source, and an energy discrimination type radiation line sensor for pipe thinning inspection (model number C13247) made by Hamamatsu Photonics K.K. was used as the sensor.

[0087] The X-ray source and the line sensor were placed facing each other across the pipe, and the line sensor was moved horizontally or vertically along the pipe to take images. The distance L between the X-ray source and the line sensor was 1200 to 1500 mm, and the effective length per image was 400 mm. The moving speed of the line sensor was 7.5 mm / sec, the accumulation time was 0.1 sec, and the measurement pitch was 0.75 mm. As a result of the measurements, no clogging of the polymer was observed.

[0088] In addition, the height of deposits or piled water in the pipe can be measured even if the height is not uniform by scanning the sensor vertically as shown in Figure 8. [Explanation of symbols]

[0089] 1. Non-destructive testing equipment 2. Screening Equipment 10 Radiation source 20 Sensors 30 Means of transportation 50 Data processing device 51 Data Entry Method 52 Data output means 53 Memory means 54 Control Means 55 Thickness reduction amount calculation method 56 Reference section estimation curve calculation means 57 Height calculation method 70 Ultrasonic thickness gauge 101 Piping

Claims

1. A non-destructive inspection method for measuring the amount of wall thinning of a structure or the height of deposits accumulated inside the structure using a radiographic method, comprising: The amount of radiation that penetrates the structure by scanning the sensor (count number C ｎ A transmission dose measurement step of measuring the The transmitted radiation dose at the measurement point (count number C ｎ ) and the transmitted dose at the measurement point (count number C ｎ ) and the reference point transmission dose (count number C ０ a height calculation step of calculating an amount of wall thinning Δt of the structure or a height Δt of deposits deposited inside the structure by using the above equation (4); A non-destructive inspection method comprising the steps of: Δt=ln(C) ｎ / C ０ ) / μ・・・・(4) Here, C ｎ : Number of counts at the measurement point (transmitted radiation amount) C ０ : Number of counts at the reference point (transmitted radiation dose) Δt: Amount of thinning or height of deposit (mm) μ: Linear attenuation coefficient of the pipe (mm －１ ) For deposit measurements, the linear attenuation coefficient of the deposit (mm －１ )

2. The reference portion estimation curve is a transmission dose (count number C ｎ 2. The nondestructive inspection method according to claim 1, wherein the calculation is performed by subjecting data of healthy sections out of the data of healthy sections to regression analysis.

3. The reference portion estimated curve is The transmitted radiation dose at the measurement point (count number C ｎ A provisional reference portion estimated curve calculation step of calculating a provisional reference portion estimated curve by performing regression analysis on the The transmission dose (count number C ０ ') and the transmitted dose at the measurement point (count number C ｎ ) and the transmitted dose (count number C ｎ A masking data selection step of selecting data to be masked from the The transmitted dose (count number C ｎ A step of calculating an estimated reference curve by performing regression analysis on the estimated reference curve; 2. The non-destructive inspection method according to claim 1, wherein the calculation is performed by:

4. Further, a linear attenuation coefficient acquisition step of acquiring a linear attenuation coefficient μ is included, The linear attenuation coefficient acquisition step includes: Thickness t ０ A test piece having a known radiation amount is placed between the radiation source and the sensor, and the sensor is scanned to measure the amount of radiation (count number C) that has passed through the structure and the test piece. ｎt０ A test piece penetration dose measurement step for measuring the radiation dose; The transmitted radiation dose at the measurement point (count number C ｎ ) and the transmitted dose (count number C ｎt０ ) and calculating the linear attenuation coefficient μ by equation (6); Including, 2. The nondestructive testing method according to claim 1, characterized in that, in the test piece transmission dose measurement step, when measuring the amount of wall thinning Δt of the structure, a test piece made of the same material as the structure is used, and when measuring the height Δt of deposits accumulated inside the structure, a test piece made of the same material as the deposits is used. μ=ln(C ｎ / C ｎt０ ) / t ０ ・・・・(6) Here, C ｎ : Number of counts at the measurement point that penetrated the structure (transmitted radiation dose) C ｎｔ０ : Number of counts at the measurement point that penetrates the structure and test piece (Transmitted Dose) t ０ : thickness of test piece (mm) μ: Linear attenuation coefficient of the pipe (mm －１ ) For deposit measurements, the linear attenuation coefficient of the deposit (mm －１ )

5. 5. The non-destructive inspection method according to claim 4, wherein the test piece transmission dose measuring step is performed by attaching or placing the test piece on the sensor.

6. 2. The non-destructive inspection method according to claim 1, wherein a radiation source that irradiates radiation onto the structure being inspected is of a fixed type, an integral type that moves integrally with the sensor, or a synchronous type that moves in synchronization with the sensor.

7. A non-destructive inspection method comprising a screening step of selecting a thinning portion or a deposition portion of the structure by using the non-destructive inspection method according to any one of claims 1 to 6.

8. A screening process for selecting a thinning portion of the structure by using the non-destructive inspection method according to any one of claims 1 to 6; a thickness measuring step of measuring the thinned portion with an ultrasonic thickness gauge; A non-destructive inspection method comprising:

9. A data processing device for a non-destructive inspection device that uses a radiological method to measure the amount of wall thinning of a structure or the height of deposits accumulated inside the structure, The amount of radiation transmitted through the structure obtained by scanning the sensor (count number C ｎ ) and performing regression analysis to calculate a reference portion estimated curve; The amount of radiation that penetrated the structure (count number C ｎ ) and the transmitted dose (count number C ０ ) using equation (4) to calculate the amount of wall thinning Δt of the structure or the height Δt of deposits deposited inside the structure; A data processing device comprising: Δt=ln(C) ｎ / C ０ ) / μ・・・・(4) Here, C ｎ : Number of counts at the measurement point (transmitted radiation amount) C ０ : Number of counts at the reference point (transmitted radiation dose) Δt: Amount of thinning or height of deposit (mm) μ: Linear attenuation coefficient of the pipe (mm －１ ) For deposit measurements, the linear attenuation coefficient of the deposit (mm －１ )

10. A data processing device according to claim 9 ; A radiation source that irradiates a structure that is an inspection target with radiation; a sensor for detecting an amount of radiation transmitted through the structure; a moving means for moving the sensor or the radiation source and the sensor; Equipped with A non-destructive inspection device characterized in that the radiation source and the sensor are of a fixed type in which the radiation source is fixed and the sensor is movable, an integrated type in which the radiation source moves integrally with the sensor, or a synchronous type in which the radiation source moves in synchronization with the sensor.

11. 11. The non-destructive inspection device according to claim 10, wherein the sensor is a line sensor.

12. A program for causing a computer to function as the data processing device according to claim 9.

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