JPH07333202A - Flaw detector of piping - Google Patents

Abstract

PURPOSE:To accurately perform the ultrasonic flaw detection from the interior of fine diameter piping even when a sonic wave emitting position is displaced. CONSTITUTION:A flaw detector is equipped with the main body part 1 having an ultrasonic probe 3 and a reflecting mirror 4 at its leading end part inserted in piping 17 filled with a liquid, a drive part 5 rotating and scanning the reflecting mirror in a circumferential direction and a displacement detecting probe 6 detecting the displacement quantity from the center axis of the piping of the main body part 1 and the inner diameter of the piping during damage detection operation. Further, a signal processing part 9 equipped with a CPU calculating the shift angle of a propagation route through which ultrasonic waves having arrived at the inner wall of the piping propagate to reach a damage part and the center direction of the cross section of the piping of the damage part from the displacement quantity and the inner diameter of the piping and a position variable part 7 controlling the position of the main body part 1 so that the calculated shift angle is received within a preset value are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe flaw detector for ultrasonically inspecting a pipe filled with a liquid such as a cooling pipe, a water pipe or a drain pipe of a power generation facility.

[0002]

2. Description of the Related Art In recent years, development of an apparatus for obtaining information from various objects to be inspected using ultrasonic waves has been advanced. In the medical field, an ultrasonic diagnostic apparatus has been commercialized that converts and displays the intensity of ultrasonic reflection signals from the inside of a living body into a two-dimensional volatility distribution image. In the industrial field, various test objects (metal, resin,
Detection applications such as detection of internal structure and damage from reflected ultrasonic waves or transmitted ultrasonic waves for ceramics, etc. are popular. In a pipe-shaped object, an ultrasonic flaw detection method from inside or outside the pipe has been studied in order to detect cracks inside the pipe wall and damages occurring on the wall surface. As a flaw detection method from the inside of the pipe, for example, a spring technique using an ultrasonic probe described in JP-A-5-45341 is known.

A conventional ultrasonic probe for flaw detection will be described below with reference to FIG. FIG. 15 shows the structure of the ultrasonic probe described in the above publication. In FIG.
101 and 102 are bevel probes, 103 is a vertical probe, 1
04 is the probe body, 105 is a spring shaft, 10
6 is a rotor shaft, and 107 is a signal line inserted in the rotor shaft. Spring shaft 105,
The rotor shaft 106 and the signal line 107 are connected to a main body (not shown).

The operation of the ultrasonic probe constructed as above will be described below. The probe main body 104 is inserted into the pipe filled with water and moved in the axial direction by using, for example, a water flow. When the portion to be inspected is reached, the rotor shaft 106 is rotated with respect to the spring shaft 105. Since the rotor shaft 106 and the probe main body 104 are directly connected to each other inside the probe main body 104 by a configuration not shown, rotation of the rotor shaft 106 causes the probe main body 104 to move relative to the spring shaft 105. Is rotated.

During such rotation of the probe body 104, the bevel probe 101, 102 and the vertical probe 1 are operated.
03, ultrasonic flaw detection is performed. The beveled probes 101 and 102 can detect damage in the pipe wall inside or in the outer wall in the circumferential direction, and the vertical probe 103 can measure the pipe wall thickness. The reason for providing two bevel probes is
This is to ensure detection of damage to the weld. The angles of the bevel probes 101 and 102 are uniquely determined by the liquid (water) inside the pipe, the material of the pipe, and the mode of ultrasonic waves propagating inside the pipe. Select the angle that maximizes the reflected wave of. Further, in this flaw detection method, it is assumed that the probe main body 104 is located on the central axis of the pipe. FIG. 16 shows the probe main body 10
4 shows the centering jigs 108 provided before and after 4, and nylon 109 is radially provided from the center of the centering jig 108. For the axial movement of the probe main body 104, the pipe 1
The nylon 109 longer than the inner diameter of 10 bends to be automatically positioned on the central axis of the pipe.

[0006]

When ultrasonic waves are obliquely incident on a subject and propagated through the inside of the subject for flaw detection, in the case of a flat-shaped subject, as described above, the flaws present inside the The reflected signal at depends on the angle of incidence. Further, in a curved object such as a pipe, the propagation direction also changes according to the direction of the incident position, so the reflected signal is affected not only by the incident angle but also by the incident position. In the conventional example, the detection performance due to the curved surface shape is prevented by approximating the shape of the pipe to a flat surface or controlling the ultrasonic wave emission position by a simple method.

However, in the small-diameter pipe, there is a problem that a slight displacement of the incident position cannot be ignored and the flaw detection performance is significantly deteriorated or the reliability of the detection result is deteriorated.

The present invention solves the above-mentioned conventional problems, and in an ultrasonic flaw detection from the inside of a small diameter pipe, an ultrasonic pipe flaw detection device capable of reducing the deterioration of the detection performance due to the displacement of the sound wave emitting position. It is intended to be provided.

The present invention also provides an ultrasonic pipe flaw detector which can evaluate the detection result according to the displacement of the sound wave emission position and present a highly reliable result.

[0010]

In order to achieve the above object, a pipe flaw detector of the present invention comprises a main body portion which is inserted into a pipe filled with a liquid and has an ultrasonic probe at its tip. A means for detecting the displacement of the main body from the center axis of the pipe and the inner diameter of the pipe during the damage detection operation, the propagation path until the ultrasonic waves that reach the inner wall of the pipe reach the damaged part, and the center direction of the pipe cross section of the damaged part. And a means for controlling the position of the main body so that the calculated deviation angle falls within a preset value. Instead of the means for controlling the position of the main body, a means for evaluating the correctness of the detection result may be provided based on the obtained deviation angle.

[0011]

According to the present invention, with the above-described structure, the deviation angle of the main body portion is detected from the displacement amount of the main body portion of the pipe flaw detector from the pipe central axis and the pipe inner diameter, and the main body portion is adjusted so that the value falls within a predetermined range. Since the position is controlled, the damage can be detected with high accuracy even if the sound wave emitting position is displaced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of the embodiments of the present invention will be described below, but before that, in detecting damage from inside a pipe, the displacement of the sound wave emitting position affects the damage detection performance. .

When ultrasonic waves are made to enter the flat object by the water immersion method and propagated in the object,
It is known that the incident angle for efficiently propagating the ultrasonic wave is specified depending on the mode of the ultrasonic wave to be propagated, that is, the longitudinal wave and the transverse wave, but depending on the material of the subject. For example, in order to efficiently enter the transverse ultrasonic wave from water into iron, it is necessary to set the incident angle near 20 degrees. The incident ultrasonic waves are refracted in a direction determined by the incident angle on the inner wall of the pipe and the sound velocity ratio of water and iron. This concept basically applies to the case where ultrasonic waves are propagated from the inside of the pipe to the inside of the pipe wall, and it is necessary to set the incident angle efficiently.

In addition, when damage in the circumferential direction existing inside the pipe wall is detected in a non-contact manner from the inside of the pipe by ultrasonic waves, the damage detection performance is affected by the displacement of the sound wave emitting position, and more specifically, the center of the pipe. The greater the displacement from the axis, the weaker the reflected signal from damage. When the reflected signal becomes weak, it becomes difficult to separate it from the reflected signals other than the damage, and reliability becomes low, for example, erroneous detection results are presented. This phenomenon will be described below with reference to the drawings.

FIG. 13 is a diagram showing the concept of a flaw detection method for detecting damage in the circumferential direction existing inside the pipe from inside the pipe. In FIG. 13, reference numeral 51 is an ultrasonic probe, 52 is a pipe to be inspected, 53 is circumferential damage inside the pipe wall, 54 is an ultrasonic wave incident position, and 55 is an inner wall surface at the incident position 54. The normal direction, 56 is the incident angle, 57 is the propagation path in water, 58 is the propagation path inside the subject, and 59 is the tube central axis of the pipe 52. In order to show the concept in FIG. 13, the ultrasonic probe 51 is floated inside the pipe 52, but it is actually included in the proper main body portion, and the sound wave emitting position is from the incident position 54 to the pipe central axis 59. It is on the line connecting In the figure, it is assumed that the pipe is on the central axis 59. Although only part of the pipe 52 is shown, the pipe 52 is actually cylindrical and the inside is filled with water.

The operation of the above arrangement will be described below. The ultrasonic waves emitted from the ultrasonic probe 51 are
It reaches the incident position 54 through the propagation path 57. A part of the ultrasonic wave that has reached the incident position 54 is reflected in a direction symmetrical to the propagation direction 57 with respect to the normal direction 55, and a part of the ultrasonic wave propagates in the pipe 52 by the propagation path 58 inside the subject and is damaged. 53
To reach. The ultrasonic waves that reach the damage 53 are reflected,
It reverses the path and returns to the ultrasonic probe 51, and is received as a reflected signal from the damage. Here, the internal propagation path 5
The closer 8 is to the damage in the vertical direction, the stronger the reflected signal becomes, and the damage can be detected more easily. When the sound wave emitting position is in the above position, damage 53 in the circumferential direction of the pipe 52
On the other hand, the internal propagation path 58 is in the vertical direction, and the damage can be efficiently detected.

Next, with reference to FIG. 14, a state in which the sound wave emitting position is displaced will be described. FIG. 14 is a conceptual diagram when viewed from the direction A shown in FIG. 13, that is, the tube central axis 59 direction. In FIG. 14, 60 is the amount of displacement from the tube central axis 59 of the ultrasonic probe 51, 61 is the incident position when displaced,
62 is a propagation path in water when displaced, 63 is a propagation path in the subject when displaced, 64 is an incident position 61
Is the normal direction.

The ultrasonic wave that has passed through the propagation path 62 from the ultrasonic probe 51 and reached the incident position 61 is refracted according to the angle between the normal direction 64 and the propagation path 62, and passes through the propagation path 63. Reach damage 53. That is, the propagation path 63 is displaced from the center of the pipe cross section of the damage 53, and as a result, the reflected wave from the damage 53 becomes weak.

The angle δ can be geometrically determined by the inner diameter of the pipe 52 and the displacement amount 60, where δ is the angle of deviation between the propagation path 63 and the center of the pipe cross section of the damage 53. The inner diameter of the pipe is 47 mm (millimeter), 23 mm,
Table 1 shows the calculation results of δ with respect to the displacement amount 60 in the case of 13 mm.

[Table 1]

We measured the reflection signal from the damage 53 with respect to the displacement amount 60 using the pipes having inner diameters of 23 mm and 13 mm which were provided with damage on the outer surface of the pipe in the circumferential direction.
When the inner diameter is 23mm, the displacement is about 0.5mm
It was found that the intensity of the reflected signal from the damage 53 was about half of that in the case of zero displacement when the displacement was about 0.3 mm. When δ is calculated from these displacement amounts based on Table 1, it becomes about 3 °. That is, the change in the intensity of the reflected signal from the main body is closely related to the angle δ, and the allowable angle δ is determined by designating the intensity of the reflected signal necessary for detection.
When the range of the angle δ is determined, the allowable displacement amount of the sound wave emitting position where damage can be detected is determined.

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an ultrasonic pipe flaw detector according to a first embodiment of the present invention, and FIG. 2 is a schematic block diagram of a signal processing unit 9. In FIG. 1, 1 is a bottomed cylindrical main body, 2 is a plurality of beams axially projecting from the open end of the main body 1, and 3 is an ultrasonic probe fixed to the main body 1 with beams 2. Is. Reference numeral 4 is a reflection mirror that reflects the ultrasonic waves emitted from the ultrasonic probe 3, and has a tilt so that the ultrasonic waves are incident on the inner wall of the pipe at a desired incident angle depending on the material of the pipe. 5 is a reflection mirror 4
A drive unit for rotating and scanning, 6 is a displacement detecting probe provided on the side surface of the main body unit 1, two or more are position changing units provided on the main body unit 1, and 8 is an external operation not shown. A signal line 9 for transferring the detection result to a person, a signal processing unit 9 connected to the ultrasonic probe 3, the driving unit 5, the displacement detecting probe 6, the position changing unit 7, and the signal line 8. Is piping.

In FIG. 2, reference numeral 10 is a displacement detection transmission / reception unit connected to a plurality of displacement detection probes 6, 11 is a displacement detection signal processing unit connected to the displacement detection transmission / reception unit 10, and 12 is a displacement detection signal processing unit. An ultrasonic wave transmitting / receiving unit connected to the ultrasonic probe 3, 13 is a flaw detection signal processing unit connected to the ultrasonic wave transmitting / receiving unit 12, 14 is a drive control unit connected to the driving unit 5, and 15
Is a position control unit connected to the position changing unit 7, and 16 is a control of the displacement detection signal processing unit 11, the flaw detection signal processing unit 13, the drive control unit 14, the position control unit 15, and an output of the displacement detection signal unit 11. Is a CPU unit for obtaining the angle δ from The damage detection result output from the flaw detection signal processing unit 13 is transferred to the outside through the signal line 8.

The operation of the above arrangement will be described below. First, as shown in FIG.
7 Insert inside. The ultrasonic probe 3 irradiates an ultrasonic pulse with a signal from the ultrasonic transceiver 12. The ultrasonic waves reflected by the reflection mirror 4 are applied to the inner wall surface of the pipe 17 at a desired incident angle and propagate inside the pipe wall. When there is damage in the circumferential direction as described above, the ultrasonic probe 3 receives a strong reflection signal from the damage, the signal processing unit 13 detects the damage, and transfers it to the outside by the signal line 8. .
This damage detection operation is performed by the reflection mirror 4 accompanying the rotation of the drive unit 5.
Is continuously performed during the rotation of, the ultrasonic waves are scanned in the circumferential direction, and the main body 1 is moved in the axial direction of the pipe 17 by, for example, a water flow to scan the entire region of the pipe 17.

Next, the plurality of displacement detecting probes 6 measure the distance from the main body to the pipe 17, and the pipe 1 of the main body 1 is measured.
7 The displacement amount from the central axis and the inner diameter of the pipe 17 are obtained by the displacement detection signal processing unit 11. As the displacement detecting probe 6,
For example, an ultrasonic sensor can be used. The CPU unit 16 obtains the aforementioned angle δ from the displacement amount obtained by the displacement detection signal processing unit 11 and the inner diameter of the pipe 17. The position control unit 15 is C
The angle δ obtained by the PU unit 16 is compared with a value stored in advance, and when the angle δ is large, the position varying unit 7 controls the position of the main body unit 1 so that the angle δ becomes small. The position varying unit 7 is composed of, for example, a piezoelectric actuator and minute blades, and is moved by moving the minute blades vertically and horizontally with respect to the water flow.
The position of can be changed. Since the predetermined value stored in advance depends on the form of damage to be detected, etc., it may be set, for example, by adding S / N from the previous empirical value of the test pipe provided with the standard damage.

As described above, according to this embodiment, the pipe 1
In the pipe flaw detection device for detecting damage existing inside the pipe wall from inside 7, the pipe 17 of the main body 1 is operated during the damage detection operation.
The displacement amount from the central axis and the pipe diameter are determined by the displacement detection probe 6 and the displacement detection signal processing unit 11, and the CPU unit 16 determines the angle δ.
Is calculated and the position of the main body 1 is controlled by the position control unit 15 and the position changing unit 7 so that the angle δ is kept within a predetermined value. It becomes possible to detect.

The function and effect of this embodiment are not lost even if the signal processor is separated from the main body 1 and arranged outside the pipe 17. Further, in the above configuration, the ultrasonic waves emitted from the ultrasonic probe 3 are two-dimensionally scanned in the circumferential direction of the pipe by the reflection mirror 4.
Any other structure may be used as long as the ultrasonic scanning is performed, for example, by directly rotating the ultrasonic probe 3.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a diagram showing the configuration of the pipe flaw detector in the second embodiment of the present invention, and FIG. 4 is a schematic block diagram of the signal processing unit 18. The present embodiment is different from the first embodiment in that there is no position changing portion 7 and position control portion 15, and instead, a plurality of elastic alignment arms 18 radially provided on the side surface of the main body portion 1 are provided. And a detection and evaluation section 19 connected to the CPU section 16 and the flaw detection signal processing section 13. Although the main body 1 can be accurately positioned on the central axis of the pipe 17 by the configuration of the aligning arm 18, the material of the aligning arm 18 is set to ensure smooth movement in the pipe axis direction. A synthetic resin material having a small friction coefficient is preferable.

The operation of the above arrangement will be described below. First, ultrasonic waves are two-dimensionally scanned in the circumferential direction of the pipe 17 by the same method as in the first embodiment, and at the same time, the main body 1
The displacement amount of is detected. In this case, the main body 1 is positioned substantially on the central axis of the pipe 17 by elastically contacting the tip of the aligning arm 18 with the inner wall of the pipe 17.
The value of the angle δ obtained by the CPU unit 16 is transferred to the detection / evaluation unit 19. On the other hand, the flaw detection signal processing unit 13 detects a reflection signal from damage based on the reflection signal waveform output from the ultrasonic probe 3, and transfers the result to the detection evaluation unit 19. When the angle δ is within a preset predetermined value, the detection evaluation unit 19 detects the flaw detection signal processing unit 1.
The detection result of No. 3 is transferred to the signal line 8 as it is, and in other cases, the reliability of the detection result is low. For example, a signal indicating that there is a defective main body position or an unmeasured area is transferred to the signal line 8. To do.

As described above, according to this embodiment, the pipe 1
In the ultrasonic pipe flaw detector for detecting damage existing inside the pipe wall from inside 7, the displacement amount from the center axis of the pipe 17 of the main body 1 and the pipe diameter are displaced with the displacement detecting probe 6 during the damage detecting operation. The detection signal processing unit 11 calculates the angle δ, the CPU unit 16 calculates the angle δ, and the detection evaluation unit 19 evaluates the reliability of the detection result based on the angle δ. Good damage detection is possible.

The signal processor 20 may be separated from the main body 1 and arranged outside the pipe 17. Further, in the above-mentioned configuration, although the ultrasonic waves emitted from the ultrasonic probe 3 are two-dimensionally scanned in the circumferential direction of the pipe by the reflection mirror 4, if they are two-dimensionally scanned in the circumferential direction of the pipe. ,
For example, another configuration such as directly rotating the ultrasonic probe 3 may be used. Further, the detection evaluation unit 19 may transfer both the angle δ and the detection result in order to obtain the judgment of the operator.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a view showing the arrangement of a pipe flaw detector according to the third embodiment of the present invention. In FIG. 5, reference numeral 21 is a flaw detection main body for detecting damage existing inside the wall of the pipe 17 inside the pipe 17, and reference numeral 22 is a flaw detection processing unit outside the pipe 17. Two
Is a beam, 3 is an ultrasonic probe fixed to the tip of the flaw detection main body 21 by a plurality of beams 2, and 4 is a reflection mirror that reflects the ultrasonic waves emitted from the ultrasonic probe 3, and the material of the pipe is Has a tilt that allows the light to enter the pipe inner wall portion at a desired incident angle depending on Reference numeral 6 is a displacement detecting probe provided on the side surface of the main body 1, and 8 is a signal line for electrically connecting the main flaw detection body 21 and the flaw detection processing section 22. In this embodiment, the first
The position changing unit 7 as in the embodiment of FIG. Instead, as in the second embodiment, a plurality of elastic alignment arms 18 radially attached to the side surface of the flaw detection main body 21 are provided, and the flaw detection main body 21 is placed on the central axis of the pipe 17. Position it roughly. Reference numeral 23 is a drive transmission shaft that mechanically connects the flaw detection main body portion 21 and the flaw detection processing portion 22.

In the flaw detection processing unit 22, 5 is a drive unit connected to the drive transmission shaft 23, 14 is a drive control unit connected to the drive unit 5, and 10 is a displacement detection probe 6 and a signal line 8. A displacement detection transmission / reception unit connected via the reference numeral 11, a displacement detection signal processing unit 11 connected to the displacement detection transmission / reception unit 10,
Reference numeral 2 is an ultrasonic wave transmitting / receiving unit connected to the ultrasonic probe 3 via a signal line 8, 13 is a flaw detection signal processing unit connected to the ultrasonic wave transmitting / receiving unit 12, 16 is a CPU unit, and 19 is a flaw detecting unit. A detection / evaluation unit connected to the signal processing unit 13 and the CPU unit 16,
A display unit 24 is connected to the detection and evaluation unit 19.

The operation of the above arrangement will be described below. The flaw detection main body 21 is inserted into the pipe 17, and the drive transmission shaft 23 is pushed out to move in the pipe axis direction.
The flaw detection main body 21 is roughly piped by the alignment arm 18.
7 Centrally located. Next, the drive unit 5 rotates the drive transmission shaft 23 in response to a signal from the drive control unit 14, and the drive transmission shaft 23
The reflection mirror 4 is rotated by the rotation of. Drive transmission shaft 23
Is the rotational force generated by the drive unit 5 outside the pipe 17
In order to transmit the flaw to the flaw detection main body portion 21 inside 7, it is necessary to have both the flexibility characteristic and the torque transmission characteristic. For example, the rectangular wire may be formed into a spring shape.
Further, in order to efficiently transmit the rotational force, the drive transmission shaft 2
As shown in FIG. 6, 3 may be arranged in a pipe 23A made of a flexible material such as synthetic resin.

Two-dimensional scanning of ultrasonic waves in the circumferential direction of the pipe 17, detection of the displacement of the main body 1, detection of the angle δ, and evaluation of the damage detection result performed by the detection evaluation unit 19 are carried out by the method shown in the second embodiment. The output result of the detection evaluation unit 19 is transferred to the display unit 24 and provided to the operator. As a result, the operator can determine the presence / absence of damage, and the presence / absence of a region in which damage cannot be detected with high accuracy.

As described above, according to this embodiment, the pipe 1
In the pipe flaw detection device for detecting damage existing inside the pipe wall from inside 7, the pipe 17 of the main body 1 is operated during the damage detection operation.
The displacement amount from the central axis and the pipe diameter are obtained by the displacement detection probe 6 and the displacement detection signal processing unit 11, the CPU unit 16 calculates the angle δ, and the detection evaluation unit 19 detects the detection result from the angle δ. By performing the evaluation and displaying on the display unit 24, it is possible to detect the damage with high accuracy even if the sound wave emitting position is displaced. (Example 4)

Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a diagram showing the configuration of the pipe flaw detector in the fourth embodiment of the present invention, and FIG. 8 is a schematic block diagram of the signal processing unit 29. In FIG. 7, reference numeral 25 is a main body portion, 26 is a polymer piezoelectric film arranged on the front surface of the reflection mirror 3, 27 is a probe holder for enclosing and fixing the ultrasonic probe 3 and the reflection mirror 4, and 28 is a probe. A drive unit for rotating the tentacle holder 27, 29 is a signal processing unit, and other configurations are almost the same as those in the first embodiment. In FIG. 8, the signal processing unit 29 is different from that of the first embodiment in that the ultrasonic wave transmitting / receiving unit 12 has an ultrasonic wave transmitting unit 12A connected to the ultrasonic probe 3, a polymer piezoelectric film 26, and flaw detection. The point is that the ultrasonic wave receiving unit 12B connected to the signal processing unit 13 is separated.

The operation of the above arrangement will be described below. First, the main body 25 of the pipe flaw detector is placed in the pipe 17.
By using the displacement detecting probe 6, the position varying unit 7 and the signal processing unit 29, and by using the same method as in the first embodiment.
The position displacement amount of the main body portion 25 in 7 and the posture control are performed.

The polymer piezoelectric film 26 provided on the front surface of the reflection mirror 4 has a wavelength of 1/4 of the wavelength so that ultrasonic waves can easily pass therethrough.
It has a certain thickness. For example, when the piezoelectric polymer film 26 is formed of a copolymer of vinylidene fluoride and ethylene trifluoride and the frequency of ultrasonic waves is 10 MHz, its thickness is 60 μm.
It will be about m. Further, the polymer piezoelectric film 26 having a thickness of about 60 μm has a superior thickness for transmitting / receiving ultrasonic waves of 10 MHz.

Electrodes made of, for example, gold are thinly provided on both surfaces of the piezoelectric polymer film 26. However, when the reflection mirror 4 is made of a metal or a metal layer is provided on the reflection surface, no electrode may be provided on the surface of the polymer piezoelectric film 26 in contact with the reflection mirror 4. Ultrasonic probe 3 and reflection mirror 4
Are arranged so as to face each other inside the probe holder 27, and the probe holder 27 is connected to the drive unit 28.

The ultrasonic wave transmitted from the ultrasonic wave transmitter 12A and emitted from the ultrasonic probe 3 passes through the piezoelectric polymer film 26 and reaches the reflection mirror 4. The ultrasonic waves that have reached the reflection mirror 4 are reflected by the reflection mirror 4, and again pass through the polymer piezoelectric film 26 and reach the pipe 17. The reflection mirror 4 is configured so that the incident angle of the ultrasonic wave is easily transmitted to the pipe 17, and the ultrasonic wave applied to the pipe propagates inside the pipe wall. The ultrasonic waves are reflected by the damage inside the pipe wall, and the polymer piezoelectric film 26 is irradiated again. The reflected ultrasonic wave received by the polymeric piezoelectric film 26 is detected by the flaw detection signal processing unit 13. Further, by rotating the probe holder 27 by the drive unit 28, it is possible to scan the pipe 17 by 360 degrees, and it is possible to detect damage in the entire circumferential direction of the pipe 17.

The polymeric piezoelectric film 26 has a smaller range of ultrasonic wave tailing compared to an inorganic piezoelectric material, and thus has a high distance resolution, a flat and wide frequency characteristic, and is an excellent material for reception. Damage can also be detected.

As described above, according to this embodiment, the pipe 1
In a pipe flaw detector for detecting damage existing inside the pipe wall from inside 7, the inorganic piezoelectric material receives by receiving the reflected signal from the damage by the polymer piezoelectric film 26 arranged in front of the reflection mirror 4. A higher range resolution is obtained and smaller damage can be detected.

In the first embodiment shown in FIG. 1, the reflection mirror 4 is connected to the drive unit 28, and the ultrasonic probe 3 is connected to the beam 2 arranged at the tip of the main body 25 and does not rotate. Although the configuration is adopted, the same configuration may be applied to the fourth embodiment.
In addition, this embodiment can be applied to other embodiments than the first embodiment.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a view showing the arrangement of a pipe flaw detector according to the fifth embodiment of the present invention. FIG. 10 is a schematic sectional view of the ultrasonic probe 31 of FIG. In FIG. 9, 30 is a main body, 31 is a main body 30.
Connected to the ultrasonic probe, 32 is an ultrasonic probe array composed of a plurality of electrodes, and 33 is a probe protective film provided to protect the ultrasonic probe 31 from damage. . The rest of the configuration is almost the same except for the reference numerals 2, 3, 4, and 5 of the first embodiment, and the configuration of the signal processing unit is the same as that of the signal processing unit 9 of the first embodiment indicated by reference numerals 5 and 14. Except for the fact that they are almost the same, the ultrasonic probe 3 and the ultrasonic transmitter / receiver 12 are slightly different.

In FIG. 10, 34 is a polymer piezoelectric film for transmitting and receiving ultrasonic waves, 35 is a back electrode portion, and the polymer piezoelectric film 34 is connected to the front surface. 36 is the back electrode part 35
And a rear surface electrode take-out portion for connecting the ultrasonic wave transmitting / receiving section, 37 is a front surface electrode provided on the surface of the polymer piezoelectric film 34,
Reference numeral 38 is an insulating portion for insulating the front surface electrode 37 from the back surface electrode portion 35, 39 is a front surface electrode lead-out portion provided in the insulating portion 38 for connecting the front surface electrode 37 and the ultrasonic wave transmitting / receiving portion,
θ is the inclination angle of the back electrode portion 35.

The operation of the above arrangement will be described below. First, the pipe flaw detector main body 30 is inserted in the pipe 17, and the main body 3 in the pipe 17 is inserted in the same manner as in the first embodiment by using the displacement detection probe 6 and the signal processor.
The position of 0 is detected. The position varying unit 7 controls the posture so that the main body unit 30 becomes horizontal in the vicinity of the central axis of the pipe 17, and stabilizes the incident angle of the ultrasonic waves emitted from the ultrasonic probe 31 to the pipe 17.

The ultrasonic wave emitted from the ultrasonic probe 31 to the pipe 17 is set to an angle which allows the ultrasonic wave to easily penetrate into the inside of the pipe wall.
The angle of incidence at which ultrasonic waves can easily pass differs depending on the piping material.
In order to radiate the ultrasonic wave at an incident angle that is easily transmitted, the back electrode portion 35 is provided with an inclination angle θ, and if the pipe 17 is made of iron, the inclination angle θ is 20 degrees. By selecting the inclination angle θ suitable for the piping material in this way, it becomes possible to efficiently transmit the ultrasonic waves inside the piping wall.

The ultrasonic probe 31 is composed of a plurality of ultrasonic probe arrays 32.
Is a polymeric piezoelectric film 34 made of, for example, a copolymer of vinylidene fluoride and ethylene trifluoride, provided on the surface of the back electrode portion 35, and a plurality of fan-shaped tips arranged at equal intervals on the surface are cut off. The surface electrode 37 is made of, for example, gold. The front surface electrode 37 is provided on the front surface of the insulating portion 38 so that the front surface electrode 37 does not come into contact with the rear surface electrode portion 35.
Connected with. The back electrode portion 35 penetrates the insulating portion 38 and is connected to the back electrode extraction portion 36.

Back surface electrode extraction portion 36 and front surface electrode extraction portion 39
Is connected to an ultrasonic transmission / reception unit (not shown), first transmits and receives ultrasonic waves with one surface electrode 37 of the ultrasonic probe array 32 to detect damage, and then with the next adjacent surface electrode 37. It transmits and receives ultrasonic waves to detect damage. By repeating this operation, damage is detected in the entire circumferential direction of the pipe 17.

As described above, according to this embodiment, the pipe 17
An ultrasonic probe 31 provided with an ultrasonic probe array 32 so as to have an inclination angle θ according to a pipe material in a pipe flaw detector for detecting damage existing inside the pipe wall.
By providing the above, it is possible to detect damage inside the pipe wall without using a mechanically movable part such as a drive part or a reflection mirror.

In the present embodiment, the number of the surface electrodes 37 for transmitting and receiving ultrasonic waves at one time of the ultrasonic probe array 32 is set to one, but two or more surface electrodes 37 at the same time can be used at the same time. Ultrasonic waves may be transmitted and received. Further, although the ultrasonic probe 31 is the ultrasonic probe array 32 including the plurality of surface electrodes 37, the surface electrode 3 is formed on the entire surface of the polymer piezoelectric film 34.
By providing 7, an ultrasonic probe 31 may be configured. Further, although the plurality of front surface electrodes 37 and the back surface electrode portion 35 of the polymer piezoelectric film 34 are used, the front surface electrode 37 and the back surface electrode portion 35 may be divided into a plurality of parts. Further, although the back surface electrode portion 35 is configured to have the inclination angle θ according to the piping material, the rear surface electrode portion 35 may be configured to be horizontal to the piping 17 by setting the inclination angle θ to 0 degree.

Further, in the present embodiment, as in the first embodiment, the position of the main body portion 30 is located on the central axis of the pipe 17 by using the displacement detecting probe 6, the position varying portion 7 and the like. However, as in the second embodiment, the aligning arm 1 is controlled.
While using 8 to locate on the central axis of the pipe 17,
The displacement detection probe 6, the CPU unit 16, the detection evaluation unit 19 and the like may be used to evaluate the detection result. (Example 6)

Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 11 is a schematic view of a pipe flaw detector according to the sixth embodiment of the present invention. In FIG. 11, 40 is a water intake provided on the front surface of the main body 1 in the direction of movement in the pipe, 41 is a flow path through which water taken in from the water intake 40 passes, and 42 passes through a flow path 41 from the water intake 40. This is a drainage port through which water is discharged, and these constitute the aligning means. The main body 1 is provided with two or more intake ports 40, flow channels 41, and drain ports 42, respectively.
Is independent of the other flow paths 41, and the water that has entered through the respective water intake ports 40 does not affect the water flowing through the other flow paths 41. Further, the drainage port 42, which is connected to the water intake port 40 via the flow path 41, is provided on the opposite side with respect to the central axis of the main body 1, and the water taken in from one of the water intake ports 40 is not provided. The water is discharged from a drainage port 42 provided on the opposite side of the central axis of the main body 1. The other structure is the same as that of the third embodiment shown in FIG.

The operation of the above arrangement will be described below. First, the main body 1 is inserted into the pipe 17, and as shown in the first embodiment, the damage existing inside and outside the pipe wall is detected. A cross-sectional view of the pipe 17 cut in the radial direction is shown in FIG. Further, FIG. 12B shows the flow velocity distribution near the central axis of the cross section of the pipe 17 when the flow of water in the pipe 17 is assumed to be laminar. As shown in FIG. 12B, the flow velocity distribution is maximum at the center of the cross section of the pipe 17 and is 0 on the pipe wall surface.

When the main body 1 is located on the central axis of the pipe 17, the flow velocity of water taken in from each water intake port 40 is equal, and the flow velocity of water discharged from the drain port 42 is equal. Therefore, there is no difference in the flow velocity of the water discharged from each drain port, and the main body 1 is held so as to be located at the center of the pipe.

Next, when the main body 1 is displaced from the center axis of the pipe 17, the flow velocity of the water taken in from the water intake port 40 is different, and the flow velocity of the water discharged from the drain port 42 is also different. Intake port 4 of intake port 40 close to the central axis of pipe 17
The flow velocity of the water taken in from 0 is faster than the flow velocity of the water taken in from the intake port 40 far from the central axis of the pipe 17, and the drainage connected to the intake port 40 near the central axis of the pipe 17 via the flow path 41. The flow velocity of the water discharged from the mouth 42 is increased. Therefore, with the configuration shown in FIG.
Receives a force toward the center of the pipe 17. That is, when the water in the pipe 17 is a laminar flow, the flow velocity distribution of the water in the pipe 17 causes the main body 1 to always receive a force that is located on the central axis of the pipe 17.

As described above, according to this embodiment, the pipe 1
7 In the pipe flaw detector for detecting damage existing inside and outside the wall of the pipe from the inside, the flow velocity distribution in the pipe is utilized by providing a plurality of water intakes 40, flow paths 41, and drainage ports 42. Even if the main body 1 is displaced, the main body 1 can be positioned near the center axis of the pipe 17, and it is possible to detect damage with high accuracy and high reliability. The configuration of this embodiment is the same as that of the aligning arm 1 shown in FIGS.
It is an alternative to eight.

[0058]

As is apparent from the above embodiment, the present invention has a main body portion which is inserted into a pipe filled with a liquid and has an ultrasonic probe at its tip portion, and a main body portion during damage detection operation. Means for detecting the amount of displacement from the central axis of the pipe and the inner diameter of the pipe, and the displacement angle between the propagation path until the ultrasonic waves reaching the inner wall of the pipe reach the damaged part and the pipe cross-section center direction of the damaged part And a means for controlling the position of the main body so that the calculated deviation angle is within a preset value. Therefore, instead of the means for controlling the position of the main body, In addition, since a means for evaluating the correctness of the detection result based on the obtained displacement angle is provided, it is possible to detect damage accurately even if the sound wave emitting position is displaced.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a pipe flaw detector according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a processing unit according to the first embodiment.

FIG. 3 is a schematic perspective view of a pipe flaw detector according to a second embodiment of the present invention.

FIG. 4 is a schematic block diagram of a processing unit according to a second embodiment.

FIG. 5 is a schematic perspective view of a pipe flaw detector according to a third embodiment of the present invention.

FIG. 6 is a schematic block diagram of a processing unit according to a third embodiment.

FIG. 7 is a schematic perspective view of a pipe flaw detector according to a fourth embodiment of the present invention.

FIG. 8 is a schematic block diagram of a processing unit according to a fourth embodiment.

FIG. 9 is a schematic perspective view of a pipe flaw detector according to a fifth embodiment of the present invention.

FIG. 10 is a schematic sectional view of an ultrasonic probe according to a fifth embodiment.

FIG. 11 is a schematic perspective view of a pipe flaw detector according to a sixth embodiment of the present invention.

FIG. 12 is a schematic diagram showing the flow velocity distribution of water in the pipe in the sixth embodiment.

FIG. 13 is a conceptual diagram of a flaw detection method for detecting damage in the circumferential direction existing inside the pipe from inside the pipe.

FIG. 14 is a conceptual diagram of an ultrasonic wave propagation path when the sound wave emission position changes from the center of the pipe cross section.

FIG. 15 is a conceptual diagram of a conventional ultrasonic probe for flaw detection.

FIG. 16 is a conceptual diagram of a centering method for a conventional ultrasonic probe for flaw detection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Beam 3 Ultrasonic probe 4 Reflection mirror 5 Drive part 6 Displacement detection probe 7 Position variable part 8 Signal line 9 Signal processing part 10 Displacement detection signal processing part 11 Displacement detection signal processing part 12 Ultra Sound wave transmission / reception unit 13 Flaw detection signal processing unit 14 Drive control unit 15 Position control unit 16 CPU unit 17 Piping 18 Alignment arm 19 Detection and evaluation unit 20 Signal processing unit 21 Flaw detection main body unit 22 Flaw detection processing unit 23 Drive transmission shaft 24 Display unit 25 Main body 26 Polymer piezoelectric film 27 Probe holder 28 Drive unit 29 Signal processing unit 30 Main body unit 31 Ultrasonic probe 32 Ultrasonic probe array 33 Probe protective film 34 Polymer piezoelectric film 35 Backside electrode unit 36 Back Electrode Extraction Part 37 Front Surface Electrode 38 Insulation Part 39 Front Electrode Extraction Part 40 Water Intake 41 Flow Channel 42 Drainage Port

Claims (13)

[Claims] 1. A body portion having an ultrasonic probe at a tip end thereof, which is inserted into a pipe filled with a liquid, and a displacement amount of the body portion from a pipe central axis and a pipe inner diameter during a damage detecting operation. Means for detecting the displacement angle between the propagation path until the ultrasonic waves reaching the inner wall of the pipe reach the damaged portion and the pipe cross sectional center direction of the damaged portion from the displacement amount and the pipe inner diameter, and the determination A pipe flaw detector equipped with a means for controlling the position of the main body so that the deviation angle falls within a preset value. 2. A main body part having an ultrasonic probe at a tip end thereof which is inserted into a pipe filled with a liquid, a means for arranging the main body part substantially on the central axis of the pipe, and a damage detecting operation. Means for detecting the amount of displacement of the main body from the pipe center axis and the pipe inner diameter, and the deviation between the propagation path until the ultrasonic waves reaching the pipe inner wall reach the damaged part and the pipe cross-sectional center direction of the damaged part A pipe flaw detector comprising: a means for obtaining an angle from the displacement amount and the pipe inner diameter; and a means for evaluating whether or not the obtained deviation angle is within a preset value and evaluating the detection result. 3. The pipe flaw detector according to claim 1, wherein the signal processing unit is housed inside the main body and is connected to the outside by a signal line. 4. The pipe flaw detector according to claim 1, wherein the signal processing unit is arranged outside the pipe and is connected to the main body by a signal line. 5. A main body part which is inserted into a liquid-filled pipe and has an ultrasonic probe at a tip end thereof, wherein the main body part pipes ultrasonic waves emitted from the ultrasonic probe. A reflection mirror for reflecting the inner wall so as to irradiate the inner wall at a desired incident angle, a driving means for rotationally scanning the reflection mirror in the circumferential direction, and a plurality of displacement detection probes provided on the side surface of the main body. And a displacement detecting means for obtaining a displacement amount with respect to the pipe central axis and a pipe inner diameter based on a signal from the displacement detecting probe, and a displacement amount with respect to the pipe central axis and a pipe inner diameter obtained by the displacement detecting means. Based on, the calculation means for obtaining the deviation angle between the propagation path until the ultrasonic waves reaching the inner wall of the pipe reach the damaged portion and the pipe cross-sectional center direction of the damaged portion, and based on the signal from the calculation means Control means for controlling the position of the main body, Pipe flaw detector equipped with. 6. A main body part which is inserted into a pipe filled with a liquid and has an ultrasonic probe at a tip end thereof, wherein the main body part pipes ultrasonic waves emitted from the ultrasonic probe. A reflecting mirror for reflecting the inner wall so as to irradiate the inner wall at a desired incident angle, a driving means for rotationally scanning the reflecting mirror in a circumferential direction, and an aligning means for arranging the main body portion on substantially the central axis of the pipe. A plurality of displacement detection probes provided on the side surface of the main body, and displacement detection means for determining the displacement amount with respect to the pipe central axis and the pipe inner diameter based on signals from the displacement detection probes. , Based on the displacement amount with respect to the pipe center axis obtained by the displacement detection means and the pipe inner diameter, of the propagation path until the ultrasonic waves reaching the inner wall of the pipe reach the damaged part and the pipe cross-sectional center direction of the damaged part Calculating means for obtaining the deviation angle, and A pipe flaw detector equipped with a detection and evaluation means that evaluates the detection result by determining whether or not the corner angle is within a preset value. 7. A pipe flaw detection apparatus in which a flaw detection main body portion inserted inside a pipe and a flaw detection treatment portion arranged outside the pipe are connected via a drive transmission shaft, wherein the flaw detection main body portion has a beam at its tip. Ultrasonic probe fixed through, a reflection mirror that reflects the ultrasonic waves emitted from the ultrasonic probe so as to irradiate the inner wall of the pipe at a desired incident angle, and on the side surface of the main body A plurality of displacement detection probes,
A plurality of position changing parts provided on the side surface of the main body, wherein the flaw detection processing part rotates the reflection mirror of the main part in the circumferential direction via the drive transmission shaft; Displacement detecting means for obtaining the displacement amount with respect to the pipe center axis and the pipe inner diameter based on the signal from the displacement detecting probe of the main body portion, and the displacement amount with respect to the pipe center axis and the pipe inner diameter obtained by the displacement detecting means. Based on, and the calculation means for obtaining the deviation angle between the propagation path until the ultrasonic waves reaching the inner wall of the pipe reach the damaged part and the pipe cross-sectional center direction of the damaged part,
A pipe flaw detection device comprising: a position control unit that controls a position variable unit of the main body unit based on a signal from the calculation unit. 8. A pipe flaw detection apparatus in which a flaw detection main body portion inserted inside a pipe and a flaw detection treatment portion arranged outside the pipe are connected via a drive transmission shaft, wherein the flaw detection main body portion has a beam at its tip. The ultrasonic probe fixed through, a reflection mirror that reflects the ultrasonic waves emitted from the ultrasonic probe so as to irradiate the inner wall of the pipe at a desired incident angle, and the main body portion of the pipe Aligning means positioned substantially on the central axis,
A plurality of displacement detection probes provided on the side surface of the main body, wherein the flaw detection processing unit rotationally scans the reflection mirror of the main body in the circumferential direction via the drive transmission shaft. Means, a displacement detecting means for obtaining a displacement amount with respect to the pipe center axis and a pipe inner diameter based on a signal from the displacement detecting probe of the main body portion, and a displacement amount with respect to the pipe center axis obtained by the displacement detecting means. Based on the inner diameter of the pipe, the calculation means for obtaining the deviation angle between the propagation path of the ultrasonic waves reaching the inner wall of the pipe until reaching the damaged portion and the pipe cross-sectional center direction of the damaged portion, and the obtained deviation angle is preset. A pipe flaw detector equipped with a detection and evaluation means for judging whether or not it is within a predetermined value and evaluating the detection result. 9. The pipe according to claim 5, further comprising a piezoelectric film provided on the front surface of the reflection mirror and capable of transmitting an ultrasonic wave, and an ultrasonic wave receiving section connected to the piezoelectric film. Flaw detector. 10. A pipe flaw detector equipped with a main body having an ultrasonic probe at a tip end thereof, which is inserted into a pipe,
The ultrasonic probe is provided with a plurality of circumferentially arranged piezoelectric films on the surface of the conical back electrode so as to irradiate ultrasonic waves to the inner wall of the pipe at a desired incident angle. The ultrasonic probe array has a surface electrode, and the main body part is provided with a means for conducting flaw detection by sequentially energizing the surface electrodes of the ultrasonic probe array, and a plurality of means provided on the side surface of the main body part. A displacement detecting probe, a displacement detecting means for obtaining a displacement amount with respect to a pipe central axis and a pipe inner diameter based on a signal from the displacement detecting probe, and a pipe central axis obtained by the displacement detecting means. Based on the displacement amount and the pipe inner diameter,
Calculation means for obtaining the deviation angle between the propagation path until the ultrasonic waves reaching the inner wall of the pipe reach the damaged part and the pipe cross-section center direction of the damaged part, and the position of the main body part based on the signal from the calculation means And a position control unit for controlling the pipe flaw detection device. 11. A pipe flaw detector equipped with a main body which is inserted into the pipe and has an ultrasonic probe at a tip end thereof,
The ultrasonic probe is provided with a plurality of circumferentially arranged piezoelectric films on the surface of the conical back electrode so as to irradiate ultrasonic waves to the inner wall of the pipe at a desired incident angle. The ultrasonic probe array has a surface electrode, and the main body part sequentially energizes the surface electrodes of the ultrasonic probe array to perform flaw detection; and the main body part on the center axis of the pipe. Centering means, a plurality of displacement detecting probes provided on the side surface of the main body, and a displacement amount with respect to the pipe central axis and a pipe inner diameter based on signals from the displacement detecting probes. Based on the displacement detection means for obtaining and the displacement amount with respect to the pipe center axis obtained by the displacement detection means and the pipe inner diameter, the ultrasonic wave reaching the inner wall of the pipe propagates to the damaged part and the damaged part. A calculation means for obtaining a deviation angle from the pipe cross-section center direction of Pipe flaw detector and a detection evaluation unit whose serial determined offset angle evaluate the detection result by determining whether accommodated within a preset value. 12. The pipe flaw detection according to claim 6, 8 or 11, wherein the aligning means is a plurality of aligning arms that are radially provided around the main body part and have their tips elastically contacting the inner wall of the pipe. apparatus. 13. An aligning means is provided with a plurality of water intakes provided on the front surface of the main body in the direction of movement in the pipe, and a liquid taken from one of the water intakes to another liquid flow taken in from the other water intake. 7. A flow path that allows the liquid to pass through without affecting the flow path, and a drain outlet for discharging the liquid that has passed through the flow path.
Alternatively, the pipe flaw detector according to 8 or 11.