JP5090952B2 - Ultrasonic flaw detector - Google Patents

Description

  The present invention relates to an ultrasonic flaw detector, and in particular, relates to an ultrasonic flaw detector that scans a circumferential surface of a pipe and performs flaw detection, and particularly, ultrasonic waves that perform flaw detection in narrow places where pipes are densely packed in a power plant or the like. The present invention relates to a flaw detection apparatus.

  Patent Document 1 discloses an ultrasonic flaw detection apparatus that performs flaw detection by scanning the outer peripheral surface of a pipe. This ultrasonic flaw detector includes a guide rail mounted on an outer peripheral surface of a pipe, an annular rack formed on the guide rail, a traveling vehicle that travels along the outer peripheral surface of the pipe, and an annular mounted on the traveling vehicle. An ultrasonic probe mounted on the traveling vehicle scans the circumferential surface of the pipe when the pinion is rotationally driven. In this ultrasonic flaw detector, in order to attach a traveling vehicle to a guide rail, a pair of holding mechanisms are arranged on the left and right sides of an annular rack as a driving mechanism. The pair of holding mechanisms includes left and right slopes formed on both side surfaces of the guide rail, and a pair of rotating bodies that slide on the left and right slopes, respectively.

JP 55-134352 A (see FIG. 6)

  However, according to the ultrasonic flaw detector of Patent Document 1, when the traveling vehicle travels along the pipe circumferential direction, it is difficult to sufficiently suppress the rattling of the traveling vehicle, in particular, rattling in the pipe radial direction, This backlash may adversely affect the accuracy of ultrasonic flaw detection. Further, according to the ultrasonic flaw detection apparatus of Patent Document 1, since the pair of holding mechanisms are arranged so as to largely straddle the guide rail, the ultrasonic flaw detection apparatus is enlarged, particularly in the pipe radial direction of the traveling vehicle. May increase and interfere with other pipes that stand close to the pipe being scanned.

  An object of the present invention is to provide an ultrasonic flaw detector that can be configured compactly and can perform stable running or scanning.

  In a first aspect, the present invention is an ultrasonic flaw detection apparatus that scans a circumferential surface of a pipe and performs flaw detection, and is detachably attached to the circumferential surface of the pipe along the circumferential direction of the pipe. An extending ring, an ultrasonic flaw detection head capable of scanning on the peripheral surface of the pipe, a main body mounted with the ultrasonic flaw detection head and capable of rotating on the peripheral surface of the pipe via the ring, and the main body And a guide mechanism that guides the rotation of the main body, and is interposed between the main body and the ring. A drive mechanism that freely rotates, and a sliding mechanism that is interposed between the main body and the ring and that controls the posture of the main body by sliding or sliding with the ring when the main body rotates. And along the axial direction of the pipe, the guide mechanism The driving mechanism is arranged on one side and the sliding mechanism is arranged on the other side as a center, and the guide mechanism includes a guide rail formed in an annular shape on the ring, and a guide rail pivotally supported on the main body. A pair of main rollers for clamping, and the drive mechanism includes a rack formed in an annular shape on the ring, and a pinion that is pivotally supported by the main body and meshes with the rack. An ultrasonic flaw detector comprising: an outer peripheral surface formed in an annular shape on the ring; and a sub-roller supported by the main body and sliding or sliding on the outer peripheral surface.

(1) A driving mechanism is arranged on one side and a sliding mechanism is arranged on the other side, with the guide mechanism as the center, along the axial direction of the pipe, so that the traveling state of the ultrasonic flaw detector is stabilized. For example, even when rattling occurs between the rack and the pinion, the drag mechanism that opposes the force generated on the drive mechanism side is generated by the sliding mechanism that is located on the opposite side across the guide mechanism. The balance of the ultrasonic flaw detection apparatus main body is maintained, and stable running of the main body and high-accuracy ultrasonic flaw detection are possible.
(2) Along with the axial direction of the pipe, with the guide mechanism as the center, the drive mechanism is arranged on one side and the sliding mechanism is arranged on the other side, so that the main body of the ultrasonic flaw detector can be configured compactly, In particular, the height of the portion straddling the drive mechanism can be reduced. As a result, it is possible to scan the outer peripheral surface of the pipe even in a narrow place where a plurality of pipes stand. For example, since the height of the ultrasonic flaw detector according to the present invention can be suppressed to 150 mm or less, flaw detection is possible even at a location where the distance between the pipes is about 200 mm.
(3) Since the main body and the ring of the ultrasonic flaw detector of the present invention can be configured simply and compactly, the ring can be attached to the pipe to be flaw-detected and the ultrasonic flaw detector main body can be attached to the ring. For example, when flaw detection is performed in a high-dose work environment at a nuclear power plant, the setting time, particularly the installation time, can be shortened, so that the amount of exposure can be reduced. In addition, the number of workers for performing flaw detection can be reduced.

  In a preferred embodiment of the present invention, the guide mechanism adjusts the guide mechanism so that the pair of main rollers can sandwich the guide rail by enlarging or reducing the distance between the pair of main rollers. The sliding mechanism includes a sliding mechanism adjusting mechanism that moves the sub roller up and down along the radial direction of the ring and adjusts the load of the sub roller on the outer peripheral surface of the ring. By providing such an adjustment mechanism, adaptability to the flaw detection environment is improved, stable running of the main body is ensured, and reliability of ultrasonic flaw detection is improved.

  In a preferred embodiment of the present invention, the adjustment mechanism for the guide mechanism connects its operating means (for example, the first knurling 21) and the guide mechanism (for example, the upper and lower rollers 2a and 2b) via a link mechanism. The holding force for the ring of the ultrasonic flaw detector main body is adjusted.

  In a preferred embodiment of the present invention, the adjusting mechanism for the guide mechanism includes a first operating means (for example, a knurling), a first screw shaft that rotates integrally with the first operating means, and a first screw shaft. A screw block that is screwed together and guided in the linear motion direction by the bottom surface of the main body or the frame, a swingable first link having one end connected to the screw block, and an intermediate portion of the first link A second link having one end connected to the portion and the other end pivotally supported by the main body or the frame, and a lower roller directly or indirectly on the other end of the first screw shaft. Is supported. By providing such an adjustment mechanism, adaptability to the flaw detection environment is improved.

  The adjusting mechanism for the sliding mechanism includes a second operating means (for example, knurl), a second screw shaft that rotates integrally with the second operating means, and a surface orthogonal to the second screw shaft. A bevel gear mechanism that transmits the rotational force of the second screw shaft to the gear shaft, a sub-roller that is directly or indirectly connected to the gear shaft and can be raised and lowered, and the sub-roller, An outer peripheral surface on the ring that is slidable.

  Preferably, the first and second screw shafts are arranged coaxially, so that the ultrasonic flaw detector is further compact.

  In a preferred embodiment of the present invention, the main body includes an L-shaped frame, and at least the pinion and the pair of main rollers are arranged in a space surrounded by the L-shaped frame. Such an arrangement can particularly suppress the height of the ultrasonic flaw detector.

  An ultrasonic flaw detection apparatus according to a preferred embodiment of the present invention includes an axial drive mechanism for moving the ultrasonic flaw detection head along the axial direction of the pipe, and moving the ultrasonic flaw detection head in the axial direction. And a means for performing flaw detection a plurality of times on different circuit lines (a plurality of flaw detection line modes) and obtaining flaw detection results based on the flaw detection results of the plurality of times. This improves the accuracy with respect to scratch assessment.

  In a preferred embodiment of the present invention, the ring is separable and can be integrated into an annular shape.

  In a preferred embodiment of the present invention, the ultrasonic flaw detection head is disposed so as to face the circumferential surface of the pipe in a non-contact manner along the circumferential direction and along the axial direction of the pipe. A pair of grooves that are closed and open toward the circumferential surface, and a pair of holes that are formed at the axial ends of the grooves and supply a medium to the surface between the pair of grooves through the grooves, respectively. Have.

  According to the ultrasonic flaw detector of the present invention, vertical flaw detection and oblique flaw detection are possible, but preferably phased array flaw detection is performed.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of an ultrasonic exploration apparatus according to an embodiment of the present invention. FIG. 2 is a mechanism diagram of the ultrasonic flaw detector shown in FIG. 1 viewed from the back.

  Referring to FIGS. 1 and 2, this ultrasonic exploration device is a device that scans the outer peripheral surface of the pipe P to detect flaws on the pipe P, and is attached to the outer peripheral surface of the pipe P so as to be detachable. A ring R extending along the circumferential direction of P, an ultrasonic flaw detection head H capable of scanning the outer peripheral surface of the pipe P, and an ultrasonic flaw detection head H mounted on the peripheral surface of the pipe P via the ring R A main body M that can freely circulate, a guide mechanism G that is interposed between the main body M and the ring R, is attached to the ring R so as to be freely circulated, and guides the circulation of the main body M; A drive mechanism D that is interposed between R and drives the main body M so as to freely rotate, and is interposed between the main body M and the ring R. When the main body M circulates, the main body M is slid or slid by the ring R. And a sliding mechanism C for controlling the posture of the.

  In this ultrasonic exploration apparatus, along the axial direction of the pipe P, the drive mechanism D is disposed on one side and the sliding mechanism C is disposed on the other side with the guide mechanism G as the center. The guide mechanism G includes a guide rail 1 formed in an annular shape on the ring R, and a pair of main rollers 2 a and 2 b that are pivotally supported by the main body M and sandwich the guide rail 1. The drive mechanism D includes a rack 3 formed in an annular shape on the ring R, and a pinion 4 that is pivotally supported by the main body M and meshes with the rack 3. The sliding mechanism C includes a predetermined outer peripheral surface 5 formed in an annular shape on the ring R, and a sub-roller 6 that is supported by the main body M and slides or slides on the outer peripheral surface 5.

[Ring R]
FIG. 3 is a partial view of a connecting portion of the ring shown in FIG. FIG. 4 is various overall views of the ring shown in FIG. Referring to FIGS. 3 and 4, the ring R is formed so as to be separable or annularly integrated, and includes, for example, a pair of semicircular rings R1 and R2. A positioning knock pin 7a and a fixing bolt 7b are arranged on the end face of one semicircular ring R1. A pin hole (not shown) into which the knock pin 7a can be fitted and a bolt hole (not shown) into which the bolt 7b can be fitted or screwed are formed on the end face of the other semicircular ring R2. An engagement lever 7c is swingably attached to one semicircular ring R1 via an engagement bolt 7d, and an engagement lever 7c is engageable to the other semicircular ring R2. A combined bolt 7e is attached. When the pair of semicircular rings R1 and R2 are integrated, they are positioned by the knock pin 7a and the pin hole, temporarily fixed by the engagement lever 7c and the engagement bolts 7d and 7e, and fixed by the bolt 7b.

  FIG. 4 shows a plurality of types of rings R or semicircular rings R1 having different diameters and an arcuate spacer 8. By mounting the spacer 8 on the radially inner side of the pair of semicircular rings R1, R2, the ring R can correspond to the pipes P having various outer diameters.

[Main body M and axial traveling body A]
Referring to FIGS. 1 and 2, the main body M includes an L-shaped frame F, and a pinion 4, a pair of main rollers 2 a and 2 b, and a sub roller 6 are disposed in a space surrounded by the frame F. An ultrasonic testing head H is connected to the axial traveling body A via a suspension device S. In the frame F, the motor and transmission constituting the pinion drive mechanism D for rotating the pinion 4 or the axial traveling body A is reciprocated in the axial direction of the pipe P while being guided by the linear guide 41. A motor and a transmission constituting the axial drive mechanism 40 are accommodated.

[Ultrasonic flaw detection head H]
Referring to FIGS. 1 and 2, an ultrasonic flaw detection head H is connected to the main body M via a suspension device S. FIG. 5 is a bottom view of the ultrasonic inspection head shown in FIG. Referring to FIG. 5, the ultrasonic testing head H is disposed to face the bottom surface 10 facing the outer peripheral surface of the pipe P in a non-contact manner along the circumferential direction of the pipe P and along the axial direction of the pipe P. A pair of grooves 10a, 10a that are closed and opened toward the outer peripheral surface of the pipe P, and a medium is supplied to the surface between the pair of grooves 10a, 10a formed at the pipe P axial end of the groove 10a. And a pair of holes 10b, 10b. A uniform medium film is formed between the ultrasonic inspection head H and the outer peripheral surface of the pipe P by such an arrangement of the groove 10a and the hole 10b.

[Drive mechanism D]
FIG. 6 is a partial view of the drive mechanism when the ultrasonic flaw detector shown in FIG. 1 is viewed from the back. Referring to FIGS. 1, 2, and 6, the drive mechanism D includes a rack 3 and a pinion 4, and a motor and a transmission (not shown) for driving the pinion 4 to rotate.

[Guide mechanism G]
Referring to FIGS. 1 and 2, the guide mechanism G guides the pair of main rollers 2a and 2b so that the pair of main rollers 2a and 2b can sandwich the guide rail 1 by enlarging or reducing the distance between the pair of main rollers 2a and 2b. A mechanism adjusting mechanism 20 is provided.

[Sliding mechanism C]
Referring to FIGS. 1 and 2, the sliding mechanism C includes a sliding mechanism adjusting mechanism 30 that moves the sub roller 6 up and down along the radial direction of the ring R and adjusts the load applied to the outer peripheral surface 5 of the ring R of the sub roller 6. Have.

[Details of the guide mechanism G and the sliding mechanism C and their adjusting mechanisms 20, 30]
FIG. 7 is a partial view of the guide mechanism and the sliding mechanism when the ultrasonic flaw detector shown in FIG. 1 is viewed from the back. FIG. 8 is a mechanism diagram of FIG. 9 is a cross-sectional view taken along arrow IX-IX in FIG. FIG. 10 is a mechanism diagram of the guide mechanism shown in FIG.

  Referring to FIGS. 1, 2, and 7 to 10, in particular, referring to FIGS. 2 and 9, the guide mechanism G is a pair of lower rollers 2 b that are arranged apart from each other along the circumferential direction of the pipe P. , 2b.

  Referring to FIGS. 2, 7, 9, and 10, the guide mechanism adjusting mechanism 20 includes a first knurl 21, a first screw shaft 22 that rotates integrally with the first knurl 21, A screw block 23 screwed into one screw shaft 22 and guided in the linear motion direction by the bottom surface of the frame F, and a swingable first link having one end connected to the screw block 23 via a pin 24 25, and a second link 28 having one end connected to an intermediate portion of the first link 25 via a pin 26 and the other end pivotally supported on the frame F via a pin 29. Yes. A lower roller 2 b is pivotally supported on the other end of the first screw shaft 22 via a first lifting block 27.

  When the first knurl 21 is rotated in a predetermined direction, the first screw shaft 22 translates, the screw block 23 moves linearly to the first knurl 21 side, and the other end of the first link 25 is shown in FIG. The first elevating block 27 is swung upward in the middle, the interval between the lower roller 2b and the upper roller 2a is narrowed, and the engaging force of the upper and lower rollers 2a, 2b with respect to the guide rail 1a is increased.

  Referring to FIGS. 2, 8, and 9, the sliding mechanism adjustment mechanism 30 includes a second knurling 31, a second screw shaft 32 that rotates integrally with the second knurling 31, and a second knurling shaft 32. A gear shaft 34 that rotates on a surface orthogonal to the screw shaft 32, a bevel gear mechanism 33 that transmits the rotational force of the second screw shaft 32 to the gear shaft 34, and a frame F that is screwed to the gear shaft 34. A second elevating block 35 guided in the direction, a sub-roller shaft 36 that moves up and down integrally with the second elevating block 35, a sub-roller 6 supported by the sub-roller shaft 36, and a ring R that is slidable with the sub-roller 6. An upper outer peripheral surface 5.

When the second knurling 31 is rotated in a predetermined direction, the second screw shaft 32 is rotated, the gear shaft 34 is rotated via the bevel gear mechanism 33, and the second lifting block 35 is lowered in FIG. and, the sub roller 6 is pressed against the outer circumferential surface 5, the drag F _L is generated. The force F _L is along a direction opposite to the backlash force F _R generated between the rack 3 and the pinion 4 of the drive mechanism D, by acting on the main body M, during circulation, the posture of the main body M is stabilized.

  In the guide mechanism adjusting mechanism 20 and the sliding mechanism adjusting mechanism 30, the first and second screw shafts 22 and 33 that transmit the operation force are arranged coaxially.

  With reference to FIGS. 1-10, an example of the flaw detection method using the ultrasonic flaw detector which concerns on one Example of this invention demonstrated above is demonstrated. First, a pair of semicircular ring semicircles R1 and R2 are attached to the pipe P to be flawed and integrated. Next, the main body M is held on the ring R by sandwiching the guide rail 1a on the ring R with the upper and lower rollers 2a and 2b. At this time, after engaging the upper roller with the guide rail 1a, the first knurl 21 is rotated to raise the lower roller 2b, and the upper and lower rollers 2a, 2b are engaged with the guide rail 1a with appropriate pressure. Let By this attachment, the pinion 4 on the main body M side meshes with the rack 3 on the ring R side.

  Subsequently, the second knurling 31 is rotated to lower the sub roller 6 toward the outer peripheral surface 5 of the ring R, and the sub roller 6 is brought into contact with the outer peripheral surface 5 with a load that does not rattle the main body M. To be slidable. Thereby, even during the circulation of the main body M, the balance of the main body M around the guide rail 1a is highly secured.

  Next, the drive mechanism D is turned on and the pinion 4 is driven to rotate, so that the ultrasonic flaw detection head H is rotated on the outer peripheral surface of the pipe P together with the main body M. At this time, the ultrasonic testing head H transmits ultrasonic waves toward the outer peripheral surface of the pipe P, receives reflected waves, and collects flaw detection data. After completion of one round, the axial drive mechanism 40 moves the ultrasonic flaw detection head H minutely along the pipe P axial direction. Next, the ultrasonic flaw detection head H is turned around together with the main body M again, and flaw detection data is similarly collected. This is repeated a plurality of times to obtain a multi-flaw flaw detection line mode. Thus, for example, when the flaw detection target is a welded portion of the pipe P, line flaw detection data can be automatically obtained from the left and right of the welded portion, and if there is a flaw, one flaw is detected from various accuracies. Thus, the depth, size or position of the wound can be accurately evaluated.

  The ultrasonic flaw detector according to the present invention is suitably used for flaw detection in a narrow place where piping is densely packed in a power plant or the like. For example, the ultrasonic flaw detector according to the present invention includes a base material and welded portion or pressure-resistant portion of pipes and structures made of various steels and stainless steel, a welded portion of a thick pipe, a base material flaw inspection of a main valve box, a nuclear power plant It is suitably used for inspection of welded parts of pipes, main pipes of thermal power / nuclear power plants, and welded parts of pressure vessels.

1 is an external view of an ultrasonic survey apparatus according to an embodiment of the present invention. It is the mechanism figure which looked at the ultrasonic flaw detector shown in FIG. 1 from the back. It is a fragmentary view of the connection part of the ring shown in FIG. FIG. 2 is various overall views of the ring shown in FIG. 1. FIG. 2 is a bottom view of the ultrasonic inspection head shown in FIG. 1. FIG. 2 is a partial view of a drive mechanism and a guide mechanism when the ultrasonic flaw detector shown in FIG. 1 is viewed from the back. FIG. 2 is a partial view of a guide mechanism and a sliding mechanism when the ultrasonic flaw detector shown in FIG. 1 is viewed from the back. FIG. 8 is a mechanism diagram of FIG. 7. It is IX-IX arrow sectional drawing of FIG. FIG. 8 is a mechanism diagram of the guide mechanism shown in FIG. 7.

Explanation of symbols

P Piping R Ring R1, R2 A pair of semicircular rings H Ultrasonic flaw detection head M Main body G Guide mechanism (main body M holding or mounting mechanism)
D driving mechanism C sliding mechanism S suspension mechanism F _L drag F _R backlash force first guide rails 2a, 2b main roller 3 rack 4 Pinion 5 the outer peripheral surface 6 sub roller 7a knock pin 7b bolts 7c engaging lever 7d engagement bolt 8 spacers 10a pair Groove 10b pair of holes 20 guide mechanism adjusting mechanism 21 first knurl 22 first screw shaft 23 screw block 24 pin 25 first link 26 pin 27 first lifting block 28 second link 29 pin 30 sliding Adjustment mechanism 31 for moving mechanism First knurl 32 First screw shaft 33 Bevel gear mechanism 34 Bevel gear shaft 35 Second elevating block 36 Sub roller shaft 40 Axial drive mechanism 41 Linear motion guide

Claims (2)

An ultrasonic flaw detector that performs flaw detection by scanning the circumference of a pipe,
A ring that is detachably attached to the circumferential surface of the pipe and extends along the circumferential direction of the pipe;
An ultrasonic flaw detection head that can freely scan the peripheral surface of the pipe;
A main body mounted with the ultrasonic flaw detection head and freely circulated on the peripheral surface of the pipe via the ring;
A guide mechanism that is interposed between the main body and the ring, and that is rotatably attached to the ring and guides the rotation of the main body.
A drive mechanism that is interposed between the main body and the ring and drives the main body so as to rotate freely;
A sliding mechanism that is interposed between the main body and the ring, and controls the posture of the main body by sliding with the ring when the main body circulates;
Have
Along the axial direction of the pipe, with the guide mechanism as the center, the driving mechanism is arranged on one side, and the sliding mechanism is arranged on the other side,
The guide mechanism includes a guide rail that is annularly formed on the ring, and a pair of main rollers that are pivotally supported by the main body and sandwich the guide rail.
The drive mechanism includes a rack formed annularly on the ring, and a pinion that is pivotally supported by the main body and meshes with the rack.
The sliding mechanism includes an outer peripheral surface formed in an annular shape on the ring, and a sub-roller that is supported by the main body and slides or slides on the outer peripheral surface.
An ultrasonic flaw detector characterized by that. The guide mechanism includes an adjustment mechanism for a guide mechanism that allows the pair of main rollers to sandwich the guide rail by enlarging or reducing the distance between the pair of main rollers.
The sliding mechanism includes a sliding mechanism adjusting mechanism that moves the sub-roller up and down along the radial direction of the ring and adjusts the load of the sub-roller on the outer peripheral surface of the ring;
The ultrasonic flaw detector according to claim 1, comprising:

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