JP7147305B2 - PIPING DIAGNOSTIC METHOD, PIPING DIAGNOSTIC DEVICE, AND PIPING DIAGNOSTIC SYSTEM - Google Patents

Description

The present invention relates to a piping diagnostic method, a piping diagnostic device, and a piping diagnostic system.

In factories, data centers, buildings, etc., leaks occur due to defects such as pinholes in piping used to supply cooling water, steam, chemicals, and the like. Leakage has a significant impact on factory production, safety, and equipment operation, so there is a need for technology that predicts leaks in advance rather than diagnosing them after they occur.

Techniques for diagnosing defects such as pinholes include inspection methods using acoustic data, vibration data, flow velocity data, pressure data, and the like. An example of an inspection method using data is a technique for specifying a leak position using data from an acoustic sensor (see, for example, Patent Document 1). Also, there is a technique for judging leakage from pressure data (see, for example, Patent Document 2).

JP 2013-210347 A JP-A-9-113400

However, these techniques are for diagnosing after a leak, not for predicting when the leak will occur. Also, diagnosis by ultrasound is limited to localization. Until now, there has been no technology for estimating the growth of defects such as pinholes and predicting leaks in advance.

An object of the present invention is to provide a piping diagnostic method, a piping diagnostic device, and a piping diagnostic system capable of estimating the growth of defects such as pinholes.

In one aspect, the pipe diagnosis method uses reflected waves of ultrasonic waves output by each of two or more ultrasonic flaw detectors provided in a pipe, and detects ultrasonic waves of one of the two or more ultrasonic flaw detectors. A process of estimating the distance from the ultrasonic flaw detector to the defect of the pipe and the deviation angle of the defect in the circumferential direction of the pipe with respect to the one ultrasonic flaw detector; and a process of estimating the shape of the defect according to the reflected wave signal obtained by normalizing with the deviation angle .

In another aspect, the piping diagnostic system uses two or more ultrasonic flaw detectors provided in a pipe and reflected waves of ultrasonic waves output from each of the two or more ultrasonic flaw detectors to determine the two or more A position for estimating the distance from one of the ultrasonic flaw detectors to the defect of the pipe and the deviation angle of the defect in the circumferential direction of the pipe with respect to the one ultrasonic flaw detector. an estimating unit; and a shape estimating unit that estimates the shape of the defect according to a reflected wave signal obtained by normalizing the intensity of the reflected wave by the distance and the deviation angle .

The growth of defects such as pinholes can be estimated.

1(a) is a functional block diagram of a piping diagnosis system according to Embodiment 1, and FIG. 1(b) is a block diagram for explaining the hardware configuration of an arithmetic section and a piping control section; FIG. (a) to (c) are diagrams illustrating the positional relationship between a flaw detector and a pipe. It is a figure which illustrates about the shape change accompanying the growth of a pinhole. FIG. 5 is a diagram illustrating a flowchart representing piping diagnosis processing; (a) is a diagram illustrating a reflected wave acquired by a flaw detector, and (b) is a diagram illustrating a difference between the acquired reflected wave and an initial reflected wave. FIG. 4 is a diagram illustrating sensitivity curves of respective flaw detectors; (a) is a diagram plotted against the response surface obtained from the reflected wave intensity measured with the SV wave, and (b) is plotted against the response surface obtained from the reflected wave intensity measured with the SH wave. It is a figure and (c) plots the time-dependent change of the depth of a pinhole. (a) and (b) illustrate multiple modes of temporal transition of depth h. FIG. 5 is a diagram illustrating changes in pinhole depth h; FIG. 11 is a diagram illustrating a piping diagnostic system according to a second embodiment;

Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1(a) is a functional block diagram of the piping diagnostic system 100 according to the first embodiment. As illustrated in FIG. 1(a), the piping diagnostic system 100 includes a plurality of flaw detectors 10a to 10c, an arithmetic unit 20, a display device 30, a piping control unit 40, and the like. The calculation unit 20 includes a data storage 21, a difference detection unit 22, a distance calculation unit 23, an angle calculation unit 24, a standardization unit 25, a database 26, a plot unit 27, a shape estimation unit 28, a prediction unit 29, and the like.

FIG. 1(b) is a block diagram for explaining the hardware configuration of the computing unit 20 and the piping control unit 40. As shown in FIG. As illustrated in FIG. 1B, the calculation unit 20 and the piping control unit 40 include a CPU 101, a RAM 102, a storage device 103, and the like. Each of these devices is connected by a bus or the like. A CPU (Central Processing Unit) 101 is a central processing unit. CPU 101 includes one or more cores. A RAM (Random Access Memory) 102 is a volatile memory that temporarily stores programs executed by the CPU 101 and data processed by the CPU 101 . The storage device 103 is a non-volatile storage device. As the storage device 103, for example, a ROM (Read Only Memory), a solid state drive (SSD) such as a flash memory, a hard disk driven by a hard disk drive, or the like can be used. The CPU 101 executes the piping diagnosis program stored in the storage device 103 to implement the calculation unit 20 and the piping control unit 40 . In addition, each part of the calculating part 20 and the piping control part 40 may be comprised by the circuit etc. for exclusive use, respectively.

The flaw detectors 10a to 10c are ultrasonic flaw detectors that output ultrasonic waves by vibrating transducers at a predetermined frequency, detect reflected waves of the ultrasonic waves, and output electrical signals corresponding to the reflected waves. be. The flaw detectors 10a to 10c output SV waves by vibrating the vibrators in the thickness direction, and output SH waves by vibrating the vibrators in the planar direction. The flaw detectors 10a to 10c output ultrasonic waves and detect reflected waves of the ultrasonic waves at predetermined sampling intervals. The sampling timings of the flaw detectors 10a to 10c are different from each other. The detection results of the flaw detectors 10 a to 10 c are accumulated in the data storage 21 . For example, the data storage 21 accumulates changes over time in detected reflected wave intensity for each type of ultrasonic wave.

FIG. 2(a) is a diagram illustrating the positional relationship between the flaw detectors 10a to 10c and the pipe 201. FIG. As illustrated in FIG. 2(a), the flaw detectors 10a to 10c are provided in a pipe 201. As shown in FIG. For example, the flaw detectors 10 a to 10 c are provided on the outer wall of the pipe 201 . The flaw detectors 10a to 10c are arranged at intervals of 120° in the circumferential direction of the pipe 201. FIG. As a result, the flaw detectors 10a to 10c are arranged at regular intervals in the circumferential direction of the pipe 201. As shown in FIG. The angular position at which the flaw detector 10a is arranged is assumed to be 0°, the angular position at which the flaw detector 10b is arranged is assumed to be 120°, and the angular position at which the flaw detector 10c is arranged is assumed to be 240°. A fluid is flowing in the pipe 201 . The type of fluid is not particularly limited, and may be liquid, gas, or the like.

As illustrated in FIG. 2B, the pipe 201 extends in the Z-axis direction. The flaw detectors 10a to 10c are arranged at the same position in the Z-axis direction. In the example of FIG. 2B, only the flaw detector 10a is extracted and drawn out of the flaw detectors 10a to 10c. Let the distance from the flaw detector 10a to the pinhole 202 be the distance d.

FIG. 2C is a diagram illustrating the positional relationship between the flaw detector 10a and the pinhole 202 in the circumferential direction of the pipe 201. FIG. As exemplified in FIG. 2(c), the deviation angle between the ultrasonic propagation direction of the flaw detector 10a and the circumferential direction of the pinhole 202 is defined as an angle θ.

The piping diagnosis system 100 estimates the timing of leakage by estimating the position and shape of the pinhole 202 formed in the inner wall of the piping 201 . 3A and 3B are diagrams illustrating the shape change accompanying the growth of the pinhole 202. FIG. As illustrated in FIG. 3, pinholes 202 are formed in the inner wall of pipe 201 . As the pinhole 202 grows, its diameter increases and its depth increases. When the depth of the pinhole 202 reaches the wall thickness of the pipe 201, leakage will occur. As exemplified in FIG. 3, let Φ be the diameter of the pinhole 202, and let ΔΦ be the amount of change per hour. Let h be the depth of the pinhole 202 and Δh be the amount of change per hour.

The display device 30 is a device for displaying the calculation results of the calculation unit 20, and is a liquid crystal display or the like. The pipe control unit 40 controls operation of pipes according to the calculation result of the calculation unit 20 . For example, the piping control unit 40 controls the flow rate of the fluid flowing through the piping, the temperature of the fluid, the pH of the fluid, and the like.

The details of the piping diagnosis processing by the piping diagnosis system 100 will be described below. FIG. 4 is a diagram illustrating a flowchart representing pipe diagnosis processing. As exemplified in FIG. 4, the difference detection unit 22 monitors the data accumulated in the data storage 21, focuses on any type of ultrasonic wave, and detects the most recently detected reflected wave and the initial reflected wave. is equal to or greater than a threshold value (step S1).

In the pipe 201, noise appears in the reflected wave signal due to the influence of vibration, fluid flow, and the like. Therefore, by evaluating the average noise size in advance and setting a threshold value larger than the noise size, it is assumed that the reflected wave has changed due to some defect (pinhole) instead of noise. can be estimated.

FIG. 5(a) is a diagram illustrating reflected waves acquired by the flaw detectors 10a to 10c. In FIG. 5(a), the horizontal axis represents elapsed time (ms) after the flaw detectors 10a to 10c output ultrasonic waves. The vertical axis is the absolute value (mm) of the displacement signal envelope. In FIG. 5(a), "o" represents an initial reflected wave. "X" represents the most recently detected reflected wave. For example, the absolute value of the signal envelope is acquired as data. FIG. 5B is a diagram illustrating the difference between the acquired reflected wave and the initial reflected wave. In FIG. 5(b) as well, the horizontal axis is the elapsed time (ms) after the flaw detectors 10a to 10c output ultrasonic waves, and the vertical axis is the absolute value of the displacement signal envelope (FIG. 5(a) ) is the difference (mm). In the example of FIG. 5B, the difference of the reflected wave signals is equal to or greater than the threshold at the reflected wave arrival time t. The reflected wave arrival time is the time from when the flaw detectors 10a to 10c output ultrasonic waves to when the reflected waves are received.

Next, the distance calculator 23 calculates the distance d between the flaw detectors 10a to 10c and the pinhole 202 in the Z-axis direction (step S2). The distance d can be calculated by the following formula (1). A sound velocity v represents a sound velocity in the pipe 201 .
Distance d=sound velocity v×reflected wave arrival time t/2 (1)

Next, the angle calculator 24 calculates the angle θ of the pinhole 202 (step S3). Ultrasonic waves propagate with a divergence angle that depends on the wavelength, the size of the transducer, and the like. Therefore, when the pinhole 202 is displaced in the circumferential direction from the propagation direction of the ultrasonic wave, the reflected wave is obtained although the reflection intensity is lowered. At each position of the flaw detectors 10a to 10c, the sensitivity is determined by the position (d, θ) of the pinhole 202, the size (Φ, h) of the pinhole 2, the ultrasonic frequency f of the flaw detectors 10a to 10c, and the flaw detector 10a. Depends on the transducer size D of ~10c and the speed of sound v in the pipe 201 . Here, frequency f, transducer size D, and sound velocity v are known, and distance d is calculated in step S2. Sensitivity curves according to frequency f, vibrator size D, sound velocity v, and distance d can be obtained in advance. FIG. 6 is a diagram illustrating the sensitivity curve of each flaw detector. In FIG. 6, the horizontal axis represents the angle θ of the pinhole 202, and the vertical axis represents the standard value of sensitivity. The angle θ of the pinhole 202 can be estimated by comparing the ratio of the reflected wave intensity acquired by each of the flaw detectors 10a to 10c with the sensitivity curve. In FIG. 6, position 1 corresponds to the position of the flaw detector 10a, position 2 corresponds to the position of the flaw detector 10b, and position 3 corresponds to the position of the flaw detector 10c.

Next, the normalization unit 25 normalizes the reflected wave intensity P with the position information to calculate a normalized value _P0 (step S4). Specifically, the reflected wave intensity P is normalized by distance and angle. Since the distance d = 0 and the angle θ = 0 for normalization, the normalized value P ₀ does not depend on the distance d and the angle θ, but on the diameter Φ and depth h of the pinhole 202. Become. In calculating the normalized value _P0 , an attenuation constant caused by scattering in the medium in the pipe 201 is considered. Assuming that the attenuation constant is α, the reflected wave intensity P can be expressed by the following equation (2). Note that P ₀ ′ is the reflected wave intensity at no attenuation (distance d=0). Since the attenuation constant α is known, P ₀ ′ can be calculated from the distance d.
P = P ₀ ' exp (-αd) (2)

Next, the plotting unit 27 plots the normalized value _P0 against the response surface for the diameter Φ and the depth h (step S5). FIG. 7(a) is plotted against the response surface obtained from the reflected wave intensity measured by the SV wave in which the oscillator oscillates at 5 MHz in the thickness direction. FIG. 7B is plotted against the response surface obtained from the reflected wave intensity measured by the SH wave in which the vibrator oscillates at 5 MHz in the plane direction. These response surfaces can be stored in database 26 .

Next, the shape estimator 28 compares the normalized value _P0 with each response curved surface to estimate the diameter Φ and the depth h of the pinhole 202 (step S6). Since the response to the size of the pinhole 202 differs depending on the structure (SV/SH wave, frequency, angle of refraction, etc.) of the flaw detectors 10a to 10c, the diameter Φ and the depth h can be estimated from a plurality of response surfaces. .

Next, the prediction unit 29 predicts the leak timing by fitting the temporal change of the depth h with an appropriate function (step S7). For example, as exemplified in FIG. 7C, by plotting the depth h of the pinhole 202 against the elapsed time, fitting can be performed by regression analysis or the like. From the fitting result, it is possible to predict when the depth h reaches the wall thickness of the pipe 201 . Next, the display device 30 displays the predicted leakage timing, intermediate calculation results, and the like (step S8).

The progress of the pinhole 202 depends on the environment such as temperature and humidity, the flow velocity of the fluid, the pH of the fluid, deterioration of the material of the pipe 201, and the like. Therefore, the trajectory on the response surface is different depending on these parameters. By learning the accumulated data, it is possible to classify each corrosion mode. Therefore, the piping control unit 40 controls the operation method (flow rate, water temperature, pH, etc.) of the piping 201 according to the trajectory on the response curved surface (step S9). For example, if the trajectory on the response surface matches a mode in which corrosion easily progresses, the piping control unit 40 may change the current mode to a mode in which corrosion hardly progresses.

Next, a specific example will be described. For example, assume that the reflected wave intensities obtained by the flaw detectors 10a to 10c are 0.5:0.5:0.1. In this case, by using the sensitivity curve of FIG. 6, it can be estimated that the pinhole 202 is located at the angle θ=60°. If the angle θ of the pinhole ₂₀₂ is calculated to be 60°, using the sensitivity curve of FIG. be. In this case, the normalized value _P0 normalized by the distance d and the angle θ can be calculated by the following formula (3). For example, if the normalized value _P0 is 0.02 for the SV wave and 0.03 for the SH wave, then using the response surfaces of FIGS. 7(a) and 7(b), the diameter Φ=2. 6 mm, depth h=1.1 mm.
P ₀ =P ₀ '×2 (3)

FIG. 8A is a diagram illustrating a plurality of modes of temporal transition of depth h. A dashed arrow represents mode1, and a solid arrow represents mode2. In FIG. 8(b), the time transition of the depth h changes like mode1 or mode2. For example, as illustrated in FIG. 8(b), in the case of mode 1, multidimensional function fitting can be applied. In the case of mode2, linear fitting can be applied.

FIG. 9 illustrates variations in depth h of pinhole 202 . In the example of FIG. 9, it is predicted that leakage will occur in a short period of time under the condition of mode2. Therefore, based on the results learned from the data so far, parameters such as flow rate and pH can be adjusted to mode 1 operation, and if the route is changed to mode 2', the period until leakage can be extended. .

According to this embodiment, the position of the pinhole 202 in the pipe 201 is estimated using the reflected ultrasonic waves output from the flaw detectors 10a to 10c provided in the pipe 201. FIG. Furthermore, the shape of the pinhole 202 is estimated according to the reflected wave signal obtained by normalizing the reflected wave with the position information. According to this configuration, the growth of pinholes can be estimated.

It is preferable to predict when an abnormality will occur in the pipe 201 using changes in the shape of the pinhole 202 over time. In this case, it is possible to predict the leakage timing and the like. It is preferable to estimate the shape of the pinhole 202 using the response surface of the reflected wave signal with respect to the shape of the pinhole 202 . In this case, the shape of the pinhole 202 can be estimated with high accuracy. It is preferable to estimate the shape of the pinhole 202 using the response curved surface of the reflected wave signal of the SV wave with respect to the pinhole 202 and the response curved surface of the reflected wave signal of the SH wave with respect to the pinhole 202 . In this case, by using different ultrasonic waves, the shape of the pinhole 202 can be estimated with high accuracy. It is preferable to control the operation of the pipe 201 according to the shape path of the pinhole 202 on the response surface. In this case, it is possible to extend the leakage period.

(Modification 1)
In the above example, the response surface of the SV wave of 5 MHz and the response surface of the SH wave of 5 MHz were used, but the present invention is not limited to this. A plurality of response surfaces may be used by changing the frequency of the transducer, the angle of refraction, and the like. Two or three of these total three response surfaces may be used. By using multiple response surfaces, the diameter Φ and depth h of the pinhole 202 can be estimated with high accuracy.

(Modification 2)
FIG. 10 is a diagram illustrating a piping diagnosis system according to a second embodiment; As illustrated in FIG. 10, the piping diagnostic system has a configuration in which flaw detectors 10a to 10c are connected to a server 302 through an electric communication line 301 such as the Internet. The server 302 includes the CPU 101, the RAM 102, the storage device 103, etc. shown in FIG. 1B, and implements the functions of the units shown in FIG. 1A. In this way, the piping diagnosis system may have each function distributed via electric communication lines.

In each of the above examples, the distance calculation unit 23 and the angle calculation unit 24 use the reflected ultrasonic wave output by the ultrasonic flaw detector provided in the pipe to estimate the position of the defect in the pipe. serves as an example of The shape estimating unit 28 functions as an example of a shape estimating unit that estimates the shape of the defect according to the reflected wave signal obtained by normalizing the reflected wave by the position of the defect. The prediction unit 29 functions as an example of a prediction unit that predicts when an abnormality will occur in the pipe, using the time-dependent change in the shape of the defect. The piping control unit 40 functions as an example of a control unit that controls the operation of the piping according to the path of the shape of the defect on the response surface.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

10a to 10c flaw detector 20 calculation unit 21 data storage 22 difference detection unit 23 distance calculation unit 24 angle calculation unit 25 normalization unit 26 database 27 plot unit 28 shape estimation unit 29 prediction unit 30 display device 40 pipe control unit 100 pipe diagnosis system

Claims (9)

Using reflected waves of ultrasonic waves output by each of the two or more ultrasonic flaw detectors provided in the pipe, from one of the two or more ultrasonic flaw detectors to the defect of the pipe a process of estimating the distance and the angle of deviation of the defect in the circumferential direction of the pipe with respect to the one ultrasonic flaw detector ;
and a process of estimating the shape of the defect according to a reflected wave signal obtained by normalizing the intensity of the reflected wave by the distance and the deviation angle . 2. The pipe diagnosis method according to claim 1, wherein said computer executes processing for predicting when said pipe will become abnormal using said change in shape with time. 3. The pipe diagnosis method according to claim 1, wherein in the process of estimating the shape , the shape is estimated using a response curved surface of the reflected wave signal with respect to the shape . Each of the two or more ultrasonic flaw detectors outputs SV waves and SH waves as the ultrasonic waves,
In the process of estimating the shape , the shape is estimated using a first response surface of the first reflected wave signal for the SV wave and a second response surface of the second reflected wave signal for the SH wave. 3. The piping diagnosis method according to claim 1 or 2, wherein the estimation is performed. 5. The computer executes a process of controlling the operation of the piping in accordance with the trajectory indicating the growth degree of the defect on the first response surface and the second response surface. The piping diagnosis method described in . The two or more ultrasonic flaw detectors are provided at different positions in the circumferential direction of the pipe,
In the process of estimating the deviation angle , estimating the deviation angle of the defect in the circumferential direction of the pipe using the ratio of the intensities of the reflected waves obtained by the two or more ultrasonic flaw detectors. The pipe diagnosis method according to any one of claims 1 to 5, characterized by: Using reflected waves of ultrasonic waves output by each of the two or more ultrasonic flaw detectors provided in the pipe, from one of the two or more ultrasonic flaw detectors to the defect of the pipe a position estimating unit that estimates a distance and a deviation angle of the defect in the circumferential direction of the pipe with respect to the one ultrasonic flaw detector ;
and a shape estimating unit for estimating the shape of the defect according to a reflected wave signal obtained by normalizing the intensity of the reflected wave by the distance and the deviation angle . Two or more ultrasonic flaw detectors provided in the pipe;
Using reflected waves of ultrasonic waves output by each of the two or more ultrasonic flaw detectors, the distance from one of the two or more ultrasonic flaw detectors to the defect in the pipe, and a position estimating unit that estimates a deviation angle of the pipe in the circumferential direction with respect to the one ultrasonic flaw detector of the defect ;
and a shape estimating unit for estimating the shape of the defect according to a reflected wave signal obtained by normalizing the intensity of the reflected wave by the distance and the deviation angle . Using a first reflected wave of an SV wave, which is an ultrasonic wave output by an ultrasonic flaw detector provided in a pipe, and a second reflected wave of an SH wave, which is an ultrasonic wave output by the ultrasonic flaw detector, the above a process of estimating the position of the defect in the piping;
a process of generating a first reflected wave signal by normalizing the intensity of the first reflected wave with the position information indicating the position;
a process of generating a second reflected wave signal by normalizing the intensity of the second reflected wave with the position information;
a first response surface corresponding to the first reflected wave signal and the first reflected wave signal, and a second response surface corresponding to the second reflected wave signal and the second reflected wave signal; , a process of estimating the shape of the defect based on
A piping diagnosis method, characterized in that the computer executes

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