JPH03183945A - Ultrasonic flaw detecting device - Google Patents

Abstract

PURPOSE:To enable flaw detection even for a general weld line in a narrow space by moving a traveling car along a guide rail and moving an ultrasonic probe that the traveling car holds almost along the weld line of a metallic plate. CONSTITUTION:The guide rail 8 fitted with the traveling car 19 is interposed between a lower mirror plate 1 and a heat insulator 4, the bracket at the head end of the rail 8 is inserted inward into the space; and the electromagnet at the tail end of the rail 8 is attracted to the mirror plate 1 and the rail 8 is arranged below the mirror plate 1 almost along the weld line. Then when the motor 20 fitted to a traveling car main body 14 is driven, the traveling car 19 moves along the rail 8. Consequently, the flaw detection for the mirror plate 1 can be carried out along the rail 8 by the ultrasonic probe 39 supported on the traveling car 19 through a mount part 26 and a swing arm 33. Further, when the motor 34 fitted to the mount part 26 is driven, the driving force is transmitted to a swing center shaft 32 through a belt 36 to swing the probe 39 through the arm 33, so the wide-range flaw detection can be performed in the right-left direction about the length direction of the rail 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an ultrasonic flaw detection device for metal plates installed in narrow areas.

[Prior Art] As shown in FIGS. 7 and 8, a lower head plate 1 at the bottom of the reactor pressure vessel is provided with a control rod nozzle 2 that vertically penetrates the inside and outside of the lower head plate 1. A welding line 3 is provided at the bottom of the lower mirror plate 1 so as to pass between the control rod nozzles 2.

Further, a heat insulating material 4 is provided near the bottom of the lower head plate 1 so as to pass through the control rod nozzle 2, and prevents heat generated in the reactor pressure vessel from escaping from the lower head plate 1.

In addition, 5 is a skirt provided on the foundation 6 so as to surround the lower mirror plate l, and 7 is an inspection opening formed between the foundation 6 and the heat insulating material 4 and barely large enough for a person to enter.

In this way, the lower mirror plate l and the heat insulating material 4 at the bottom of the reactor pressure vessel
In the narrow space between the control rod nozzle 2
Conventionally, a dedicated welding line 3 on a metal plate (lower mirror plate I) located in a narrow space where a large number of pipes are installed can be easily inspected. There was no ultrasonic flaw detection equipment available.

[Problems to be Solved by the Invention] Therefore, it is extremely difficult to inspect the weld line 3 of the lower head plate l located inside a narrow space in which a large number of pipes are installed.

In view of the above-mentioned circumstances, the present invention can be easily applied not only to the curved lower mirror plate at the bottom of the reactor pressure vessel, but also to general welding lines of metal plates located in a narrow space where a large number of pipes are installed. It is an object of the present invention to provide an ultrasonic flaw detection device capable of performing ultrasonic flaw detection inspection.

[Means for Solving the Problems] The present invention provides a method in which a guide rail is removably disposed on a metal plate so as to substantially follow a weld line formed on the metal plate, and a movable traveling vehicle is attached to the guide rail. , an ultrasonic flaw detection device characterized in that the traveling vehicle is provided with a swinging arm that is swingable in the left and right directions with respect to the longitudinal direction of the guide rail, and an ultrasonic probe is attached to the tip of the swinging arm. Such is the case.

[Operation] By moving the traveling vehicle along the guide rail, the ultrasonic probe held by the traveling vehicle is moved approximately along the weld line of the metal plate through the swing arm, and ultrasonic waves are emitted. I'm going to do a flaw detection inspection.

Moreover, by swinging the swinging arm left and right with respect to the longitudinal direction of the guide rail, it becomes possible to easily conduct ultrasonic flaw detection over a wide range on the left and right sides of the weld line using an ultrasonic probe.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 6 show one embodiment of the present invention, and in the figures, parts given the same reference numerals as in FIGS. 7 and 8 represent the same parts.

A curved guide rail 8 that can be freely bent and expanded around the center and has a curvature approximately equal to that of the lower head plate 1 is inserted from the inspection lower into the space between the lower head plate 1 and the heat insulating material 4 in a bent state. It will be provided in such a way that it can be done.

At the tip of the guide rail 8, there is an H-shaped bracket IO when viewed from the side that holds a pair of upper and lower rolls 9 in two stages in the front and rear.
is pivotally mounted to be able to swing up and down, and an electromagnet 11 that can be attracted to the lower mirror plate l is attached to the rear end of the guide rail 8.

A traveling vehicle main body 14 having a guide wheel 12 and a drive wheel 13 is attached to the surface of the guide rail 8 on the lower mirror plate 1 side so as to be movable along the guide rail 8.
A traveling vehicle 19 is formed by fixing a traveling vehicle bottom plate IB having a retaining ring 15 to the traveling vehicle body 14 from the surface facing the heat insulating material 4 using bolts t7, nuts 18, and the like.

The motor 20 attached to the vehicle body 14 is connected to the bevel gear 21.
22 to the drive wheel 13 to enable the traveling vehicle 19 to travel along the guide rail 8, and to adjust the holding force of a spring or the like provided between the traveling vehicle bottom plate 16 and the retaining wheel 15. The device 23 makes it possible to adjust the holding force of the vehicle 19 on the guide rail 8.

A turning center shaft 24 extending toward approximately the center of curvature of the lower end plate 1 is provided on the lower end plate l side of the traveling vehicle body 14, and the turning center shaft 24 extends toward the approximate center of curvature of the lower end end plate 1.
4, a mounting portion 26 is rotatably attached via a bearing 25,
A motor 27 fixed to the mounting section 26 is connected to the rotation center shaft 24 via a pulley 28, a belt 29, and a pulley 30, so that the mounting section 2B can be driven to rotate.

Further, the swing arm 33 is connected to the guide rail 8 via the bearing 31 and the swing center shaft 32 in front or behind the mounting section 2B.
A motor 34 is mounted to be swingable in the left-right direction a with respect to the longitudinal direction of the
6. Connect to the swing center shaft 32 via a pulley 37 so that the swing arm 33 can be driven.

An ultrasonic probe 39 is attached to the tip of the swinging arm 33 via a pressing device 38 such as a spring so as to be pressed against the lower mirror plate l.

The ultrasonic probe 39 has, for example, 0
A plurality of ultrasonic oscillators 40, 41, 42 that emit ultrasonic waves from various angles such as 30 degrees, 30 degrees, 45 degrees, etc. are installed so that ultrasonic flaw detection can be performed from multiple directions at - degrees. Make it.

Next, the operation will be explained.

The guide rail 8 with the traveling vehicle 19 attached thereto after being folded in half is inserted into the space between the lower mirror plate 1 and the heat insulating material 4 from the inspection lower, and the guide rail 8 is extended within the space to remove the guide rail. By inserting the bracket IO at the tip of the rail 8 deep into the space along the welding line 3, the bracket l
The roller 9 held by o is locked between the lower mirror plate l and the heat insulating material 4, and the electromagnet 11 at the rear end of the guide rail 8 is attracted to the position on the skirt 5 side of the lower mirror plate i, so that the guide rail 8 is approximately It is arranged below the lower mirror plate 1 along the weld line 3.

In addition, although the welding line 3 is drawn in a curved shape in FIG. 2, it is the same even if it is drawn in a straight line.

By doing so, it becomes possible to attach the traveling vehicle 19 equipped with the ultrasonic probe 39 to the bottom of the spherical lower end plate 1 so as to substantially follow the weld line 3.

When the motor 2o attached to the traveling vehicle body 14 is driven with the guide rail 8 attached to the lower mirror plate 1, the bevel gear 21
．． The driving wheel I3 rotates via the drive wheel 22, and the traveling vehicle 19 moves along the guide rail 8. This makes it possible to perform ultrasonic flaw detection on the lower mirror plate l along the guide rail 8 using the ultrasonic probe 39 supported on the traveling vehicle I9 via the mounting portion 26 and the swing arm 33.

Furthermore, when the motor 27 attached to the mounting section 26 is driven, the driving force is transmitted to the turning center shaft 24 via the pulley 28, belt 29, and pulley 3o, and the turning center shaft 24 is connected to the traveling vehicle 19.
Since it is fixed to , the mounting portion 26 rotates relatively. As a result, the ultrasonic probe 39 supported by the mounting section 26 via the swing arm 33 can be reversed 180 degrees back and forth, so the rolls 9 at both ends of the guide rail 8
And it becomes possible to perform ultrasonic flaw detection up to the edge of the electromagnet 11.

Furthermore, when the motor 34 attached to the mounting section 26 is driven,
The driving force is transmitted to the swing center shaft 32 via the pulley 35, belt 36, and pulley 37, and the ultrasonic probe 39 supported by the swing arm 33 swings, so that the guide rail of the lower mirror plate 1 It becomes possible to perform ultrasonic flaw detection in the left-right direction a with respect to the longitudinal direction of 8.

By combining the above operations, the position of the ultrasonic probe 39 is slightly advanced along the guide rail 8 as shown by the flaw detection trajectory b in FIG. As the sonic flaw detection progresses, it becomes possible to perform ultrasonic flaw detection in a wide range C along the weld line 3 while avoiding the control rod nozzle 2.

The ultrasonic flaw detection device of the present invention is not limited to the above-described embodiments, and the guide rail may be of a three-fold type, a four-fold type, or a combination of multiple rail pieces. It goes without saying that various changes can be made without departing from the gist of the invention.

[Effects of the Invention] As explained above, according to the ultrasonic flaw detection apparatus of the present invention, various excellent effects as described below can be achieved.

■ Even if the weld line has a curved surface or other complex shape, we use a removable curved rail that roughly follows the weld line, making it easy to perform ultrasonic flaw detection. It becomes possible to mount the equipped traveling vehicle on a spherical body within a narrow space provided with a large number of pipes.

■ Since the ultrasonic probe is swingably attached to the traveling vehicle via a swing arm, ultrasonic flaw detection can be performed over a wide range around the weld line.

[Brief explanation of drawings]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a view taken along the ■-■ arrow in Fig. 1, Fig. 3 is a partially enlarged perspective view of the tip of the guide rail in Fig. 1, and Fig. 4 is a side view of an embodiment of the present invention. Figure 1 is a partially enlarged perspective view of the rear end of the guide rail, Figure 5 is an enlarged drive system diagram of the traveling vehicle part in Figure 1, and Figure 6 shows the range of ultrasonic flaw detection using the device in Figure 1. The figures shown, FIG. 7 is a side view of the lower end plate of the reactor pressure vessel, and FIG. 8 is a view taken along the line ■-■ in FIG. 7. In the figure, 1 is a lower mirror plate as a metal plate, 3 is a welding line, 8 is a guide rail, 19 is a traveling vehicle, 33 is a swing arm, 39 is an ultrasonic probe, and a is in the longitudinal direction of the guide rail 8. indicates the left and right direction. 0

Claims (1)

[Claims] 1) A guide rail is removably arranged on the metal plate so as to roughly follow the weld line constructed on the metal plate, a movable traveling vehicle is attached to the guide rail, and a movable traveling vehicle is attached to the traveling vehicle in the longitudinal direction of the guide rail. An ultrasonic flaw detection device characterized in that a swinging arm that can swing freely in the left-right direction is provided, and an ultrasonic probe is attached to the tip of the swinging arm.