JPH0687865U - Ultrasonic flaw detector - Google Patents

Abstract

(57) [Summary] [Purpose] Each ultrasonic probe is run in close contact with the surface to be inspected. A main frame 30 supported by a carriage 18 that rotates along a large-diameter cylindrical portion 2c of a nozzle 2 is equipped with an axial movement portion 33 that moves in the nozzle axial direction. An arm support portion 37 having an arm base 45 that moves in the radial direction of the nozzle is provided, and the arm base 45 is provided with an arm rotation shaft 46 having an axial direction perpendicular to the nozzle axial direction and the moving direction of the arm base 45. One end is rotatably attached to the arm rotation shaft 46, and the ultrasonic probe 4 is attached to the other end.
Two arms 47 each having the number 8 and each of which is independently pressed against the surface to be inspected by the spring 49 are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ultrasonic flaw detector for flaw detection in welds and the like.

[0002]

[Prior art]

 A nozzle is connected to the reactor pressure vessel, and a pipe is connected to this nozzle. Ultrasonic flaw detection inspections are regularly conducted to confirm the soundness of the connection between the reactor pressure vessel and the nozzle, the connection between the nozzle and the pipe, and other necessary parts.

FIG. 3 shows an ultrasonic flaw detection range in the vicinity of the nozzle 2. The reactor pressure vessel 1 includes a reactor pressure vessel mating surface 2a, a curved surface portion 2b, a large diameter cylindrical portion 2c, a conical surface portion 2d, and a small diameter portion. A pipe 3 is connected through a funnel-shaped nozzle 2 having a cylindrical portion 2e. The nozzle 2 is connected to the reactor pressure vessel 1 at a connecting portion 4a, the nozzle 2 is connected to a pipe 3 at a connecting portion 4b, and the inner surface of the nozzle. The R portion 4c is in the ultrasonic flaw detection range. Since the R part 4c on the inner surface of the nozzle is clad with stainless steel, the flow velocity is high because of the R part, and cracks may occur in the stainless clad, so it is subject to inspection. The flaw detection of the R portion 4c on the inner surface of the nozzle is performed by applying an ultrasonic probe to the curved surface portion 2b on the outer surface.

FIG. 4 shows an example of an ultrasonic flaw detector, in which a ring guide 5 is attached to the outer periphery of a small-diameter cylindrical portion 2e of a nozzle 2 at a predetermined position, and a traveling wheel 6 is provided on the ring guide 5 in the circumferential direction. A traveling traveling vehicle 7 is attached, and a ball screw 9 extending in parallel to the nozzle axis direction toward the reactor pressure vessel 1 side via a frame 8 is rotatably provided on the traveling vehicle 7, and a motor 10 is connected to the ball screw 9. Then, the ball screw 9 is rotationally driven.

Guides 11 are provided in parallel on both sides of the ball screw 9, and a support arm 13 is provided on a movable base 12 that is screwed into the ball screw 9 and slidably penetrates through the guide 11. A support arm 13 is rotatably attached to the tip of the support arm 13. An arm 14 is provided, and this arm 14 is rotated by a cylinder 15. An ultrasonic probe 16 is attached to the tip of the arm 14.

FIG. 5 shows a cross section taken along the line XX of FIG. 4, and shows an engagement between the arm 14 and the ultrasonic probe 16. Two ultrasonic probes 16a and 16b are provided and rotatably attached to a rotary shaft 16c provided in a direction perpendicular to the axis of the arm 14. Two ultrasonic probes 16a and 16b are provided in one arm 14 because it is necessary to ultrasonically detect ultrasonic waves from two or more directions in one inspection place. This is to improve the inspection efficiency by detecting flaws in one inspection place with one operation.

When detecting the curved surface portion 2b, after setting the guide ring 5 at a predetermined position, the motor 10 and the cylinder 15 are operated to set the start position of the ultrasonic probe 16, Detect 7 while rotating 7 along the ring guide 5. After one rotation, the ball screw 9 is rotated by the motor 10 and the cylinder 15 is operated to feed the ultrasonic probe 16 to the reactor pressure vessel 1 side by one inspection pitch, and the traveling vehicle 7 is rotated to perform flaw detection. By repeating such an operation, flaw detection of the curved surface portion 2b is performed.

[0008]

[Problems to be solved by the device]

 However, when the ultrasonic probe 16 is rotated along the circumferential direction of the nozzle 2 in this way, the ultrasonic probes 16a and 16b do not contact the surface of the nozzle 2 uniformly, and either A phenomenon occurs in which only one contacts and the other floats. If the ultrasonic probe 16 floats above the surface of the inspection object, the flaw detection accuracy deteriorates.

The present invention has been made in view of the above-mentioned problems, and an ultrasonic flaw detector is provided in which each ultrasonic probe is provided with an arm for supporting the ultrasonic probe so as to be in close contact with the surface to be inspected. The purpose is to provide.

[0010]

[Means for Solving the Problems]

 In order to achieve the above object, a carriage that rotates along a large-diameter cylindrical portion of the nozzle, an axial movement unit that is mounted on a main frame supported by the carriage and that moves in the axial direction of the nozzle, and an axial movement Arm support having an arm base that is attached to the base and moves in the radial direction of the nozzle, and arm rotation that is attached to the arm base and has an axial direction that is orthogonal to both the axial direction of the nozzle and the moving direction of the arm base. A shaft, and a plurality of arms rotatably attached to the arm rotation shaft and having an ultrasonic probe at the other end and biased so as to be independently pressed against the surface to be inspected. It is a thing.

Further, the ultrasonic probe is attached to the other end of the arm so as to be rotatable around the arm rotation axis in the same direction and in a direction orthogonal to the rotation axis.

[0012]

[Action]

 The arm base is attached to the arm support and can move in the radial direction of the nozzle, the arm support is attached to the axial moving part and can move in the axial direction of the nozzle, and the axial moving part is mounted on the dolly and the circumference of the nozzle. Since it can move in any direction, the arm base can move in three dimensions. The arm base is provided with an arm rotary shaft having an axial direction perpendicular to the nozzle axial direction and the arm base moving direction, and one end of each of the plurality of arms is attached to the arm rotary shaft to rotate. The ultrasonic probe attached to the other end of each arm can be moved to the reactor pressure vessel side in the axial direction of the nozzle. The multiple arms are independently urged so as to be pressed toward the reactor pressure vessel, and together with the movement of the arm base in the nozzle radial direction, the surface to be inspected, which is the reactor shown in FIG. The ultrasonic probes can be closely attached to the pressure vessel mating surface 2a and the curved surface portion 2b.

Further, since the ultrasonic probe is rotatably attached to the other end of the arm about the arm rotation axis in the same direction and in a direction orthogonal to the arm rotation axis and is pressed against the inspection target surface, Even if there are irregularities on the surface, it is possible to run in close contact with the surface to be inspected.

[0014]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a side view of the present embodiment, and FIG. 2 shows a view taken along the line XX of FIG. The trolley 18 is composed of two traveling wheels 21 traveling on the large-diameter cylindrical portion 2c of the nozzle 2, two slave wheels 22 and two guide wheels 26 traveling on the conical surface portion 2d. One traveling wheel 21 and one subsidiary wheel 22 are attached to the traveling frame 20, and the traveling wheel 21 is driven by a traveling motor 27, and the shafts of the traveling wheel 21 and the subsidiary wheel 22 are connected by a chain to form the subsidiary wheel 22. To drive. An encoder (not shown) is provided on the secondary wheel 22 to measure the traveling distance. The traveling wheels 21, the subordinate wheels 22, and the guide wheels 26 are magnet wheels, and travel while attracting to the nozzles 2.

A guide arm 23 is attached to the traveling frame 20, a guide frame 25 is rotatably supported by a shaft 24, and guide wheels 26 are attached to the guide frame 25. The traveling frame 20 is rotatably attached to a support member 29 by a shaft 28, and the support member 29 is attached to a main frame 30. Two sets of traveling frames 20 are attached to the main frame 30, and two rails 31 and a rack 32 are provided in the axial direction of the nozzle 2.

A rail retainer 34 is provided on the lower surface of the axially moving portion 33 and is slidably fitted to the rail 31. Further, an axial movement motor 35 and a pinion 36 driven by the axial movement motor 35 are provided to allow the rack 32 and the meshing nozzle 2 to move in the axial direction.

An arm support portion 37 is further attached to the axial movement portion 33, and a ball screw 38 and a guide 39 are provided on the arm support portion 37 in a direction perpendicular to the main frame 30 and in parallel therewith. Both ends of the ball screw 38 are rotatably supported by bearings 40. A pulley 41 is provided at the lower end of the ball screw 38, and is rotated by a lifting motor 43 via a belt 42. The lift motor 43 is provided with an encoder 44, and measures the movement amount of an arm 47 described later.

An arm base portion 45 that is screwed with the ball screw 38 and slidably fitted with the guide 39 is provided. At the tip of the arm base portion 45, the axial direction of the nozzle 2 and the direction of the ball screw 38 (that is, movement of the arm base portion 45). The arm rotation shaft 46 is provided in a direction orthogonal to the (direction), and two arms 47 are rotatably attached. In FIG. 2, the ultrasonic probe 48 is attached to the first frame 50 so as to be rotatable about the Y axis, and the first frame 50 is attached to the second frame 51 so as to be rotatable about the X axis. The 2 frame 51 is attached to the tip of the arm 47. Further, each arm 47 is configured to be pressed against the reactor pressure vessel mating surface 2a and the curved surface portion 2b, which are the surfaces to be inspected, by the spring 49 provided around the arm rotating shaft 46 so that the ultrasonic probe 48 is brought into close contact with it. ing. The spring 49 is provided with a lock so that the spring 49 does not work when locked.

Next, the operation at the time of inspection will be described. The trolley 18 travels along the large-diameter cylindrical portion 2c of the nozzle 2 by the traveling wheels 21 and the subordinate wheels 22, but the two guide wheels 26 stick to the conical surface portion 2d of the nozzle 2 and the trolley 18 always has a large diameter. It plays the role of pressing it against the cylindrical portion 2c. Therefore, the trolley 18 always receives a force (direction toward the nuclear reactor pressure vessel 1 in the nozzle axial direction) directed to the intersection line A of the large-diameter cylindrical portion 2c and the conical surface portion 2d, and the large-diameter cylindrical portion is displaced by a considerable amount. It is automatically corrected while driving the section 2c.

The axial movement motor 35 is driven to rotate the pinion 36 and mesh with the rack 32. As the axial movement unit 33 moves on the rail 31, the nozzle 2 is moved in the axial direction and the lifting motor 43 is moved. By driving and rotating the ball screw 38, the arm base portion 45 can be moved in the radial direction of the nozzle 2. First, the spring 49 is locked, the axial movement motor 35 and the lifting motor 43 are controlled to set the ultrasonic probe 48 at the inspection start position, the lock is released, and the ultrasonic probe 48 is moved by the spring 49. It is pressed against the mating surface 2a of the reactor pressure vessel, which is the surface to be inspected, and the traveling motor 27 is driven to rotationally travel on the large diameter cylindrical portion 2c of the nozzle 2.

When the ultrasonic probe 48 makes one revolution, the position of the ultrasonic probe 48 is moved by one inspection pitch by operating the elevating motor 43, and the traveling motor 27 is driven to rotate and travel. In this way, the inspection of the reactor pressure vessel mating surface 2a is completed, and when it comes to the curved surface portion 2b, the elevating motor 43 and the axial movement motor 35 are controlled to move the ultrasonic probe 48 in accordance with the curved surface shape, and then travel. The motor 27 is driven to rotate and run. The ultrasonic probes 48 are respectively supported by independent arms 47, and in FIG. 2, are supported by a first frame 50 so as to be rotatable about the Y axis and by a second frame 51 so as to be rotatable about the X axis. Since the arm 47 is pressed against the surface to be inspected by the spring 49, each ultrasonic probe 48 should be in close contact with the surface to be inspected even if the surface to be inspected has irregularities during the rotation traveling by the traveling motor 27 and float up. And accurate ultrasonic flaw detection data can be obtained. In the above description, the flaw was detected from the reactor pressure vessel mating surface 2a to the curved surface portion 2b, but conversely, the flaw may be detected from the curved surface portion 2b to the reactor pressure vessel mating surface 2a.

[0022]

[Effect of device]

 As is clear from the above description, in the present invention, the ultrasonic probes are attached to the independently rotating arms and pressed against the surface to be inspected. Therefore, each ultrasonic probe is attached to the surface to be inspected. It is possible to get close contact and obtain accurate flaw detection data. Further, since the ultrasonic probe is rotatably attached to the arm with the rotation axis being the same direction as the arm rotation axis and the direction orthogonal to the arm rotation axis, even if the surface to be inspected has unevenness, it can be intimately contacted with the surface for flaw detection. it can.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of an embodiment of the present invention.

FIG. 2 shows a view on arrow XX in FIG.

FIG. 3 is a diagram showing an ultrasonic flaw detection range in the vicinity of a nozzle.

FIG. 4 is a diagram showing an example of a conventional ultrasonic flaw detector.

5 is a sectional view taken along line XX of FIG.

[Explanation of symbols]

 1 Reactor pressure vessel 2 Nozzle 2a Reactor pressure vessel mating surface 2b Curved portion 2c Large diameter cylindrical portion 2d Conical surface portion 2e Small diameter cylindrical portion 3 Piping 4a Nozzle and reactor pressure vessel connection 4b Nozzle and piping connection 4c Nozzle inner surface R part 18 Bogie 21 Traveling wheel 22 Secondary wheel 26 Guide wheel 30 Main frame 31 Rail 32 Rack 33 Axial direction moving part 35 Axial direction moving motor 36 Pinion 37 Arm support part 38 Ball screw 43 Lifting motor 45 Arm base part 46 Arm Rotating shaft 47 Arm 48 Ultrasonic probe 49 Spring 50 First frame 51 Second frame

Claims (2)

[Scope of utility model registration request] 1. A carriage that rotates along a large-diameter cylindrical portion of a nozzle, an axial moving portion that is mounted on a main frame supported by the carriage and that moves in the axial direction of the nozzle, and an axial moving portion. An arm support having an arm base that is attached and moves in the radial direction of the nozzle; and an arm rotation shaft that is attached to the arm base and has an axial direction in a direction orthogonal to both the axial direction of the nozzle and the moving direction of the arm base, One end of the arm rotating shaft is rotatably attached, the other end has an ultrasonic probe, and a plurality of arms urged to be independently pressed against the surface to be inspected are provided. Ultrasonic flaw detector. 2. The ultrasonic probe is rotatably attached to the other end of the arm about a rotation axis in the same direction as the arm rotation axis and a direction orthogonal to the arm rotation axis. 1. The ultrasonic flaw detector according to 1.