JPH058375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a holding device for an ultrasonic flaw detector for piping, which enables highly accurate ultrasonic flaw detection by constantly bringing the flaw detector into contact with a piping to be inspected having a curved pipe portion.

There are pipes for various plants that flow high-pressure fluids or harmful fluids, and ultrasonic flaw detection is known as one method of defect inspection for welded joints of such highly dangerous pipes. As shown in FIG. 1, which shows the external appearance of a conventional ultrasonic flaw detection device for piping, the piping to be inspected 101 is surrounded by the piping to be inspected 101.
A traveling cart 103 that slides along the band rail 102 is engaged with a band rail 102 that has a two-part structure and is detachably fixed to the band rail 102. The traveling carriage 103 is configured to rotate around the pipe 101 to be inspected by the rotation of the pinion. The traveling truck 103 has an arm rail 105 extending in a direction perpendicular to the band rail 102.
The proximal end of a lever 107 that can be displaced in the radial direction of the pipe 101 to be inspected is pivotally attached to a slider 106 which is reciprocated along this arm rail 105 by a feed drive mechanism (not shown). . A holder 11 is attached to the tip of the lever 107, which is always pressed toward the piping to be inspected 101 via a torsion coil spring 108, via a gimbal joint 109.
0 is rotatably held, and this holder 11
A flaw detector (not shown) for detecting welding defects and the like in the pipe 101 to be inspected is fixed to 0.

As shown in Fig. 2a showing the flaw detection state of a welded joint in a curved pipe section of the pipe to be inspected 101 in such a conventional ultrasonic flaw detection device, and Fig. 2b showing its cross-sectional structure taken along the line B-B. Even if the gimbal joint 109 functions so that the holder 110 and the flaw detector 112 come into close contact with the outer circumferential surface of the curved pipe 111 together with the flaw detector 112 in the curved pipe section 111 by the spring force of the torsion coil spring 108, minute It becomes difficult to trace the flaw detector 112 due to unevenness, steps, etc. of the welded joint 113. As a result, the accuracy of ultrasonic flaw detection deteriorates, resulting in a drawback that accurate defect inspection cannot be performed.

In view of the above-mentioned defects in the flaw detector holding mechanism of the conventional ultrasonic flaw detector for piping, the present invention
It is an object of the present invention to provide an ultrasonic flaw detector holding device that allows a flaw detector to easily follow even when there are irregularities on a curved pipe portion or surface, thereby improving the reproducibility of inspection.

The structure of the ultrasonic flaw detector holding device for piping according to the present invention that achieves this object includes a bracket that is rotatably attached to the tip of a lever that can move along the piping to be inspected and is pressed against the piping to be inspected. and a body rotatably held by the bracket around an axis perpendicular to the rotation center of the bracket, and an ultrasonic flaw detector integrally attached to the body and connected to the piping to be inspected. a holder having a convexly curved opposing surface; an ultrasonic propagation passage formed in the holder so as to communicate with the ultrasonic flaw detector and opening on the surface facing the piping to be inspected; and the ultrasonic propagation passage. a reservoir formed in the holder and opening to the side of the holder so as to communicate with the holder; a flexible thin film that respectively closes the opening of the reservoir and the opening of the ultrasonic propagation passage; and a flexible thin film that is sealed by these thin films. A liquid is filled in the ultrasonic propagation path and the reservoir.

Therefore, according to the present invention, the ultrasonic propagation path protruding toward the pipe to be inspected and the flexible thin film that closes it elastically slide into contact with the pipe to be inspected. The thin film of the lever can be immediately followed by elastic deformation, and the thin film is always in contact with the piping to be inspected, allowing accurate ultrasonic flaw detection.

Hereinafter, an embodiment of the ultrasonic flaw detector holding device for piping according to the present invention will be described in detail with reference to FIGS. 3 to 6.

As shown in FIG. 3 showing the appearance of this embodiment, a ring-shaped band rail 12 with a split structure is detachably attached to the pipe 11 to be inspected. A support 15 integrally connected to the traveling carriage 13 via an arcuate connecting link 14 is slidably engaged with the support 15 . A pinion (not shown) that meshes with a gear 16 formed on the band rail 12 is rotatably mounted on the traveling cart 13, and the driving rotation of this pinion causes the traveling cart 13 and the support 15 to move along the band rail 12 to the piping 11 to be inspected. orbit around. The support block 1 is connected to the support 15 via a pin 17 perpendicular to the longitudinal direction of the pipe 11 to be inspected.
A support block 18 is slidably supported between the rear end of the support block 18 and a frame 19 projecting rearward from the support 15.
A compression coil spring 20 is interposed to keep the front end of the piping 11 close to the surface of the pipe 11 to be inspected. A lever 21 and a pair of mutually parallel rods 22 projecting from the tips of the support block 18 are fitted to be slidable in a direction perpendicular to the pin 17. A rod-shaped feed nut 24, which is integral with the rod 22, is screwed onto the feed screw shaft 23, which is rotatably mounted on the feed screw shaft 23.
Therefore, by operating the lever drive motor 25 attached to the support block 18, the feed screw shaft 23 is driven to rotate, and the lever 21, together with the rod 22, is moved relative to the support block 18 in a direction parallel to the feed screw shaft 23. Move back and forth. In addition, the pipe to be inspected 11
As the mechanism for moving the lever 21 and the mechanism for bringing the lever 21 close to the surface of the pipe 11 to be inspected using a spring force, in addition to the present embodiment, a conventionally known mechanism shown in FIG. 1, for example, can be appropriately employed.

As shown in FIG. 4, which shows the planar shape of the tip of the lever 21, and FIG. An annular body 28 is rotatably supported on the bracket 26 by a bearing 30 via a pair of pins 29 perpendicular to the lever 21. As shown in FIG. 5, which shows the cross-sectional structure taken along the line V-V in FIG. are combined.
A flange portion 35 is provided on a part of the outer circumference of the holder 33 to prevent the holder 33 from coming off from the body 28 by engaging a locking pawl 34 protruding from a part of the inner circumference of the body 28. By adopting the so-called bayonet type, in which separation can be performed arbitrarily by adjusting the rotational phase of the holder 33 with respect to the body 28, it is possible to quickly exchange flaw probes 32 with different inclination angles for each holder 33. be. The holder 33 is provided with engagement teeth 37 in an arc shape along the outer periphery of the holder 33, which engages with a rotation stopper 36 made of an elastic material attached to the body 28 to prevent the holder 33 from rotating relative to the body 28. By separating the rotation stopper 36 from the engagement teeth 37, the holder 33 can be rotated relative to the body 28. Note that the holder 33
When a plurality of flaw detectors having different inclination angles are arranged in parallel and any one of the flaw detectors is selectively used, the holder 33 should be integrated with the body 28 in advance. You can also do it.
An ultrasonic propagation path 38 communicating with the flaw detector 32 is formed in the holder 33 whose surface facing the piping to be inspected 11 is curved in a convex shape. is the ultrasonic propagation path 3
A flexible thin film 39 is attached to close the opening of 8. The curvature of the surface of the holder 33 facing the pipe to be inspected 11 is equal to the curved pipe portion 40 of the pipe to be inspected 11 shown in FIG.
It is desirable to correspond to the minimum curvature of , so that the thin film 39 can be brought into contact with all parts of the pipe 11 to be inspected. Note that since this thin film 39 comes into sliding contact with the pipe 11 to be inspected, it is desirable to use a durable member with a small coefficient of friction such as polyfluoroethylene resin. or,
A pair of reservoirs 41 are formed in the holder 33 and the ultrasonic propagation passages 38 communicate with each other.
A flexible thin film 43 that closes the opening of the reservoir 41 is attached to each side of the holder 33 where the reservoir 1 is opened via a presser ring 42. These thin films 43,
A liquid 44 is filled in the ultrasonic propagation passage 38 and the reservoir 41 which are sealed by the ultrasonic propagation passage 39.
The area of the opening is set to be sufficiently larger than the area of the opening, so that the thin film 43 can absorb the elastic deformation of the thin film 39.
The shape of the ultrasonic propagation path 38 is set to be a conical shape with a cross-sectional area gradually increasing toward the thin film 39 side so as not to adversely affect flaw detection. on the other hand,
The guide plate 46 rotatably supported by the body 28 via a bearing 45 rotates around an axis perpendicular to the pin 29, and has an arc shape with a curvature corresponding to the outer diameter of the pipe 11 to be inspected. It is designed to be able to come into close contact with the inspection piping 11.

Therefore, as shown in FIG. 6 showing the working state of this embodiment, even when the tip end side of the lever 21 is located at the bent pipe section 40 of the pipe 11 to be inspected, the spring force of the compression coil spring 20 causes the bend pipe to be closed. The guide plate 46 pressed against the section 40 rotates the bracket 26 and the body 28 so as to maintain the most stable contact with the curved tube section 40, and also rotates itself to come into close contact with the curved tube section 40. As a result, the attitude of the flaw detector 32 with respect to the surface of the curved pipe section 40 is maintained constant as in the case of the straight pipe section 47.
Defect inspection of the welded joint 48 can be performed accurately and with high reproducibility. On the other hand, because the thin films 39 and 43 are elastically deformed against the unevenness of the pipe 11 to be inspected, and the thin film 39 always follows the pipe 11 to be inspected in a state of contact, there is a gap between the thin film 39 and the pipe 11 to be inspected. Therefore, it is possible to perform a more accurate defect inspection.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the external appearance of a conventional ultrasonic flaw detector holding device for piping, Fig. 2 a is a conceptual diagram of the operation showing the state when the flaw detector is positioned in a curved pipe section, and Fig. 2 b 3 is a perspective view showing the external appearance of an embodiment in which the ultrasonic flaw detector holding device for piping according to the present invention is applied to an ultrasonic flaw detection device for piping. A plan view showing the structure of its main parts,
Figure 4b is a sectional view taken along the line B-B, and Figure 5 is a cross-sectional view of the
A cross-sectional view taken along the line V-V in Figure b, and Figure 6 is a conceptual diagram of the work. In the figures, 11 is the piping to be inspected, 12 is the band rail, 13 is the traveling trolley, 15 is the support, 1
7 and 29 are pins, 18 is a support block, 20 is a compression coil spring, 21 is a lever, 22 is a rod, 2
5 is a lever drive motor, 26 is a bracket, 2
7, 30, 45 are bearings, 28 is a body, 32 is a flaw detector, 33 is a holder, 38 is an ultrasonic propagation path, 3
9 and 43 are thin films, 41 is a reservoir, 44 is a liquid,
46 is a guide plate.

Claims (1)

[Claims] 1 A bracket rotatably attached to the tip of a lever that can move along the pipe to be inspected and is pressed against the pipe to be inspected, and a bracket rotatably attached to the bracket about an axis perpendicular to the center of rotation of the bracket. a holder that is integrally attached to the body and has an ultrasonic flaw detector mounted thereon and has a convexly curved surface facing the piping to be inspected, and a holder that communicates with the ultrasonic flaw detector; an ultrasonic propagation passage formed in the holder and opening on a surface facing the piping to be inspected; and a reservoir formed in the holder and opening on the side of the holder so as to communicate with the ultrasonic propagation passage. and a flexible thin film that respectively closes the opening of the reservoir and the opening of the ultrasonic propagation path, and a liquid that is filled in the ultrasonic propagation path and the reservoir that are sealed by these thin films. Ultrasonic flaw detector holding device.