JPS61133856A - Method and apparatus for diagnosing underground pipeline - Google Patents

Abstract

PURPOSE:To improve the pipeline diagnosing speed and accuracy, by combining the detection of corrosion and deficiency on the outer wall of a pipeline by the ultrasonic thickness measurement and the detection of deficiency and corrosion on the inner wall thereof by the eddy current measurement. CONSTITUTION:A rotary unit 15 and a driver 16 are self-driven by the driver 6 and moves through a pipeline 3 to be set at a measuring point. An ultrasonic sensor 22 and an eddy current sensor 23 are driven with an ultrasonic wave transmitter/receiver 17 and an eddy current transmitter/receiver 18 and resulting ultrasonic thickness signal and eddy current signal are fed to the respective transmitter/receivers 17 and 18. The ultrasonic thickness signal is fed to an ultrasonic signal processing section to determine thickness and the minimum thickness is memorized. The eddy current signal is fed to an ultrasonic signal processing section to determine corrosion and deficiency at the measuring point. This unit moves from measuring point to point to repeat the measurement. The results obtained are processed with an arithmetic section and plotted two- dimensionally to determine the area and position of corrosion and the degree and position of cracking, which are displayed in two dimensions.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention uses ultrasonic thickness measurement and eddy current measurement in combination to detect deterioration (corrosion, defects, cracks, etc.) of underground pipelines. The present invention relates to a method for diagnosing underground pipes and an apparatus therefor.

[Conventional technology]

Conventional methods and devices for diagnosing deterioration (corrosion, defects, cracks, etc.) of underground pipelines use ultrasonic thickness measurement to detect the corroded wall thickness of the pipeline; It had one of two functions: detecting defects and cracks in the inner wall by measuring eddy currents.

FIGS. 11 and 12 are diagrams for explaining a conventional method of detecting corroded wall thickness of a pipe using ultrasonic thickness measurement. In these figures, 1 is an ultrasonic sensor, 2 is a driving device, 3 is a conduit, and 7 is an ultrasonic echo display device. The ultrasonic transmission pulses 8 emitted from the ultrasonic sensor 1 are reflected as bottom echoes 9 on the bottom surface without corrosion, while the pulses from the corroded parts 6 are reflected as defective echoes 10, and these pulses 8 and 10 time interval Δ
2・y・Δ[...(1) It can be calculated using the following formula. Similarly, the wall thickness Tdo of a portion without corrosion can be determined from pulses 9 and 10, and the reduction in wall thickness can also be calculated. In addition, 1a in FIG. 11.12 is a coupling agent.

Next, FIGS. 13 and 14 are diagrams for explaining eddy current measurement. In these figures, 4 is an eddy current sensor, 11 is an eddy current Lissajous display device, 12 is an eddy current under normal conditions (no corrosion, defects, cracks, etc.), and 12a
is the corresponding Lissajous shape, 13 is the vortex N flow when there is corrosion, defects, cracks, etc., and 13a is the corresponding modified Lissajous. This Lissajous change 13a changes (values of Δφ and Δle in the phase φ direction and eddy current strength 7e direction, respectively) depending on the size and type of corrosion, defects, cracks, etc. on the inner wall of the pipe. The change values Δφ, ΔI
By quantifying e, corrosion, defects, cracks, etc. on the inner wall of the pipe can be quantified.

[Problems to be solved by the invention] Although the ultrasonic thickness measurement method shown in FIG. Detection accuracy is poor. On the other hand, the eddy current measurement method shown in FIG. 13 is effective in detecting defects/cracks in the inner wall and thinning due to corrosion, but has poor accuracy in detecting corrosion thickness and defects in the outer wall. Therefore, conventional measuring methods and devices have the disadvantage of poor accuracy in detecting corrosion, defects, cracks, etc. throughout the inner and outer walls of the pipe.

[Means for solving problems]

In order to overcome the contradictory drawbacks of the conventional methods, the present invention detects corroded wall thickness and defects on the outer pipe wall by ultrasonic thickness measurement, and detects defects, cracks, and corroded wall thickness on the inner pipe wall by eddy current measurement. The system is characterized in that it is combined with detection and simultaneously diagnoses the pipe line from within the pipe, thereby realizing an improvement in the pipe line diagnosis speed and accuracy.

[Effect]

According to the above means, the corroded wall thickness and defects on the outer wall of the conduit are detected by ultrasonic thickness measurement, and the defects, cracks, and corroded wall thickness of the inner mold of the conduit are detected by eddy current measurement. Therefore, the inner and outer walls of the pipe can be diagnosed simultaneously from inside the pipe.
There is no internal or external positional deviation, and highly accurate diagnosis can be performed quickly.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, there is a measurement sensor 14 in the pipe line 3,
A rotating device 15 for rotationally driving this measurement sensor 14 and a driving device [16 for driving these components 14 and 15 together in the longitudinal direction of the pipe 3 are inserted.

As shown in FIG.
5 and a support spring 27 that supports the measurement sensor 14, and the rotation of the motor 25 is decelerated and transmitted to the tires 26, thereby moving in the longitudinal direction of the conduit 3. Furthermore, the tires 26 are made of non-slip rubber, etc., and are arranged in plural numbers along the inner wall surface of the conduit 3 (Fig. 2), and are controlled so that the distance between the measurement sensor 14 and the inner wall surface is always constant. be done.

Further, as shown in FIG. 3, the rotation device 15 includes a rotation motor 28, two rotation shafts that rotationally drive the measurement sensor 14, and a delivery section 30 that brings the measurement sensor 14 into contact with the inner wall of the conduit 3. The measurement sensor 14 is rotated in the circumferential direction of the conduit 3. Note that when performing ultrasonic thickness measurement using an electromagnetic ultrasonic sensor, the sending unit 30 is not required.

Next, FIG. 4 shows the configuration of the measurement sensor 14. The measurement sensor 14 includes an ultrasonic sensor 22 and an AfJ flow sensor 23, and the iIu flow sensor 23 further includes an excitation coil 23a and a detection coil 24. The ultrasonic sensor 22 receives an electric signal supplied from the ultrasonic transmitting/receiving device 17 at a constant frequency (1
MH2 to 20MH2) into ultrasonic transmission pulses 8,
While emitting toward the conduit 3, it receives the bottom echo 〇 and the defective echo 10, converts it back into an electrical signal, and supplies this signal (ultrasonic wall thickness signal) to the ultrasonic transmitting/receiving device 17.

On the other hand, the a current sensor 23 converts the electric signal supplied from the eddy current transmitting/receiving device 18 into a magnetic field using the exciting coil 23a, and generates eddy currents 12, 13 in the conduit 3 by this magnetic field. Here, the eddy current 12 is an eddy current under normal conditions, and the eddy current 13 is a changed eddy current due to a defect or the like. These eddy currents 12 , 13 generate an induced magnetic field, which is detected by the sensing coil 24 and a sensing output (eddy current signal) is supplied to the eddy current transmitter/receiver 18 .

Based on each signal obtained in this way, the ultrasonic transmitter/receiver 8
M17 is the ultrasonic transmission pulse 8. shown in FIG. 5(a).
The receiving intervals of the bottom echo 9 and the defective echo 10 are supplied to one arithmetic unit, and the eddy current transmitter/receiver 18 is configured as shown in FIG.
The eddy current intensity le shown in b) and its phase φ are supplied to the arithmetic unit 19. Note that as the ultrasonic sensor 22, it is also possible to use an ultrasonic sensor [6] consisting of an excitation coil and a detection coil, and in this case, it transmits and receives ultrasonic waves of the same frequency as the alternating magnetic field of the detection coil. be able to.

Now, as shown in FIG. 6, the arithmetic unit 19 includes a signal control section 31 that sets the measurement position, etc., and an ultrasonic signal processing section 32 that calculates the wall thickness Td at the measurement position.
, an eddy current signal processing section 33 that performs corrosion/defect calculations using eddy current Lissajous, and a calculation section 34 that performs two-dimensional plotting of the wall thickness Td, plotting corrosion and cracking, etc.
The data obtained by the calculation unit 34 is displayed on the display device 3 shown in FIG.
5 and a recorder 36 for display and recording.

Here, FIG. 7(a) is a display when the conduit 3 is scanned in the longitudinal direction, and a longitudinal section of the conduit 3 is displayed two-dimensionally.

Moreover, FIG. 7(b) is a display when the conduit 3 is scanned in the circumferential direction, and the cross section of the conduit 3 is displayed two-dimensionally. Note that the above components 35 and 36 constitute the display/recording device 20.

Next, the operation of this embodiment will be explained with reference to FIGS. 8 to 10.

FIG. 8 shows an example of scanning in the longitudinal direction, in which the rotating device 15 and the drive! The lJ device 16 is self-propelled by the drive device 16 or is towed by a loaf 38 wound around a winder 37 and runs separately, moves in the longitudinal direction of the pipe 3 at a measurement interval Δj, and moves to the measurement point n. (n = 1, 2-) (FIG. 10(I)). Note that the drive device 16
is self-propelled under the control of the signal control section 31 (FIG. 6).

In this way, when the measurement point n is determined, the ultrasonic sensor 22 and the eddy current sensor 23 are driven by the ultrasonic transmitter/receiver 17 and the eddy current transmitter/receiver 18, respectively, and the detection signal obtained as a result, that is, the ultrasonic wall thickness A signal and an eddy current signal are supplied to each transceiver device 17,18. The ultrasonic wall thickness signal is sent to the ultrasonic signal processing section 32 via the signal control section 31 in FIG. 6, and the wall thickness Tdn at the measurement point n is determined by the procedure shown in FIG. 10 (II). The minimum wall thickness Td is stored. On the other hand, the eddy current signal is
The signal is sent to the eddy current signal processing section 33 via the signal control section 31 shown in the figure, and corrosion and defects at the measurement point n are determined by the procedure shown in FIG. 10 (III). That is, from the above-mentioned eddy current strength Ie and phase φ, the value of the eddy current during normal operation is subtracted to obtain the Lissajous change △■e, Δφ, the corrosion 2-cracking is quantified, and the maximum defect etc. is determined from the maximum Δle and Δφ. Remember.

Thereafter, in the same manner, the measurement points n are moved one by one and the above measurements are repeated, and the obtained results are processed by the calculation unit 34 and plotted two-dimensionally.
The location and extent of the crack are determined and displayed in two dimensions as shown in FIG. 7(a).

Next, FIG. 9 shows an example of scanning in the circumferential direction. In this case, each measurement point n is formed by dividing the tube circumference into several tens of equal parts, and the measurement sensor 14 is brought into contact with the tube wall prior to the ultrasonic thickness measurement at each measurement point nt, and 11 measurements are carried out. When finished, it is separated from the tube wall for a certain period of time and moved to the next measurement point n+1.

The ultrasonic wall thickness signal and eddy current signal thus obtained are processed by the same algorithm as above (FIG. 10), and the results are displayed two-dimensionally as shown in FIG. 7(I)).

In this way, the wall thickness, corrosion, and defects of the pipe line 3 can be automatically diagnosed and the results can be displayed two-dimensionally.

〔Effect of the invention〕

As explained above, the present invention automatically scans the inside of a pipeline with a measurement sensor including an ultrasonic sensor and an eddy current sensor, and measures wall thickness due to outer wall corrosion of an underground pipeline using ultrasonic waves. At the same time, since the measurement of defects, cracks, corrosion, etc. that occur on the inner wall of the pipeline is carried out at the same time using eddy current, and the pipeline is completely destroyed, it is possible to measure the defects, cracks, corrosion, etc. that occur on the inner wall of the pipeline. The advantage is that cracks, defects, and corrosion can be diagnosed accurately and quickly.

Therefore, it has the advantage that it can be applied not only to inspection of cracks, defects, and corrosion of metal materials and structures, but also to shape measurement, quality inspection of prints and products, and measurement of plating and coating films. Furthermore, we manufacture thin plates as a simultaneous non-destructive inspection technology for interior and exterior walls.

Applications to maintenance and inspection technology are also conceivable.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a diagnostic device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the configuration of a drive device. Fig. 3 is a schematic diagram showing the configuration of the rotating device, Fig. 4 is a schematic diagram showing the configuration of the measurement sensor, Fig. 5 is a signal processing diagram of the above embodiment, and Fig. 6 is the configuration of the transmitting/receiving device and the calculation device. Block diagram shown,
FIG. 7 is a schematic diagram of the display/recording device 20, FIGS. 8 and 9 are sectional views for explaining diagnostic scanning, FIG. 10 is a measurement block diagram of the present invention, and FIGS. 11 and 12 are Figures 13 and 1 for explaining conventional ultrasonic thickness measurement
FIG. 4 is a diagram for explaining conventional eddy current measurement. 3...Pipeline, 5...Defect/Crack, 6.
... Corrosion, 14 ... Measurement sensor (sensor), 15 ... Rotating device, 16 ... Drive device,
17... Ultrasonic transmitting/receiving device, 18...
Eddy current transmitting/receiving device (in the above, 17.18 is the transmitting/receiving section), 2
0...display/recording device (display means), 22...
... Ultrasonic sensor, 23 ... Eddy current sensor, 31 ... Signal control section (control section), 3
2... Ultrasonic signal processing unit, 33... Vortex If! signal processing unit, 34...'atli unit (32 to 34 are calculation means); Figure 2 Figure 5 Figure 6 Figure 5b

Claims (2)

[Claims] (1) Scan the inner wall surface of the underground pipeline using a sensor that combines an ultrasonic sensor and an eddy current sensor, simultaneously measure the pipe wall thickness and pipe inner wall defects/cracks, A method for diagnosing underground pipes, characterized in that the wall thickness and defects/cracks are aggregated and calculated for each position, and the results of the aggregation and calculations are two-dimensionally displayed and recorded for each position of the pipe. . (2) A sensor that measures the wall thickness and defects/cracks of an underground pipeline, a drive device that moves the sensor in the longitudinal direction of the inner wall surface of the pipeline, and a drive device that rotates the sensor in the circumferential direction of the pipeline. a control unit that drives the drive unit and the rotation unit and controls input/output signals of the sensor; a transmitting/receiving unit that operates the sensor; and a transmitting/receiving unit that processes measurement signals obtained by the transmitting/receiving unit and a calculation means for quantifying road wall thickness and defects/cracks;
An underground pipe diagnosis device characterized by comprising a display means for dimensional or three-dimensional display.