JPH01113649A - Insertion-type ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To enable the detection of a flaw in the circumferential direction of a header- support welded part or the like of a boiler from the inside of a tube, by a method wherein a motion given by a motor for axial rotation and an axial feed motor is transmitted to a flaw-detecting element through a slide core driven along a guide member. CONSTITUTION:A nozzle 8 and an insertion guide shaft 9 connected thereto are inserted into a header 20 from a header checking hole, and the nozzle 8 is pressed against an end port 10 of a header 20. A flaw-detecting element 1, a cable 7 with balls, a motor 3 for rotation, an axial feed differential mechanism 5, an axial feed motor 4, a slide core 6, etc. are inserted into the shaft 9 from an open end thereof. The flaw-detecting element 1 is moved by the motor 4 with the core 6 moving along the shaft 9, and the insertion of the element into a welded part 11 of a tube support 21 and the header 20 is detected by a magnet 12 fixed on the outside of the shaft 9 and by a position detecting element 13. Then, the position of the flaw-detecting element 1 is fine-adjusted by the core 6 through a mechanism 15 and the motor 3, while the element is rotated in the circumferential direction. Thereby the ultrasonic flaw detection can be implemented for the welded part of the header 20 from the inside whereon a heat insulating material is not applied.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is used for detecting cracks in the circumferential direction that occur in the welded part of the header nozzle of a boiler or the welded part of attached metal of a pipe. This article relates to an insertion-type ultrasonic flaw detection device.

[Conventional technology]

Conventionally, the header of a boiler is wrapped in a thick heat-insulating material, so when detecting flaws in this part, the heat-insulating material was removed, and then the welded part was polished and magnetic particle flaw detection was performed.

[Problem that the invention seeks to solve]

In the above method, in order to perform magnetic particle flaw detection, a large number of incidental works such as removing the heat insulating material, polishing the welded part, and restoring the heat insulation after the flaw detection are required, resulting in high costs. In addition, since the headers are arranged adjacent to each other, it is not possible to use a grinder for polishing or magnetize for magnetic particle detection, so it is not always possible to check all the welded parts of the header. There were drawbacks such as the inability to conduct tests.

The present invention aims to eliminate the above-mentioned drawbacks and provide an ultrasonic flaw detection device that can perform flaw detection from inside.

[Means for solving problems]

The insertion type ultrasonic flaw detection apparatus of the present invention includes a flaw detection section equipped with a probe, a rotation motor of the flaw detection section and a shaft feed motor of the flaw detection section connected in series to the flaw detection section, the flaw detection section and the above flaw detection section. A slide core is disposed between the two motors and transmits the rotation and shaft feed motions of the shaft rotation motor and the shaft feed motor to the flaw detection section, and a guide member that guides the slide core inside the slide core. I made it.

[Effect]

In the present invention, first, the guide member is pressed and positioned at the end of the tube or the like to be inspected using a JΩ means. The flaw detection unit, which is connected in series to the rotation motor and the shaft feed motor, is passed through the guide member to locate the required location inside the pipe, etc.
At the same time, positioning is performed by positioning the slide core within the guide member. Next, by operating the rotation motor and shaft feed motor, the flaw detection section is rotated and axially fed inside the tube, etc., and the probe of the flaw detection section is moved as desired to perform the required flaw detection over the entire circumference. It can be carried out. At this time, the slide core is guided by the guide member and transmits the rotation and transportation movement by the rotation motor and shaft feed motor to the flaw detection section, so the movement is smoothly and accurately transmitted to the flaw detection section, ensuring reliable Flaw detection is carried out.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. Reference numeral 1 denotes a flaw detection section having two oblique probes (for example, the angle of incidence is 45°) facing each other in the axial direction; 2 a pair of alignment tools provided with the flaw detection section 1 sandwiched therebetween; 6 is a slide core, and the flaw detection section 1 and the slide core 6 are connected by a flexible transmission shaft 16' (see Fig. 3). u7 is a cable with a bead connected to the slide core 6; Inside 1
a flexible transmission shirt whose end is attached to the slide core 6)
16 passes through the transmission shaft 16, and the other end of the transmission shaft 16 is connected to the rotation motor 3.

The rotation motor 3 is connected to a shaft feed fine movement mechanism 5. The coaxial fine movement mechanism 5 is connected to the shaft feed motor 4 via a shaft feed nut 15 and a ball screw 14 provided in the same mechanism, as shown in FIG. 13 is a magnet connected to the shaft feed motor 4 via a beaded cable 7'.

A ball screw 14 driven by the shaft feed motor 4 is screwed into the shaft feed nut 15 provided in the shaft feed fine movement mechanism 5, and the shaft feed nut 15 moves in the axial direction by rotation of the shaft feed motor 4. Axis feed fine movement mechanism 5
and the transport simulator 4 are connected. Reference numeral 9 denotes an insertion guide shaft having a flexible portion 9' at its distal end. A hollow nozzle 8 as a guide member having a tube portion 8' is attached to the tip. Reference numeral 13 denotes a position detector fixed at a proper position on the insertion guide shaft 9. The probe, rotation motor 3, and shaft feed motor 5 of the flaw detection section 1 are connected to an external power source by a conductive wire (not shown) passing through the insertion guide shaft 9.

Details of the slide core 6 are shown in FIG. The slide core 6 is located within the tube portion 8' of the nozzle 8 when the flaw detection section 1 is inserted into the tube 21 to be flaw detected and flaw detection is performed as shown in FIG. The slide core 6 is attached to the outer periphery of the cylinder 17, and a cylinder 17 that houses the piston 18 and is made up of a ball bearing so that the piston 18 can freely move. A transmission shaft 16 connected to the rotary motor 3 and a transmission shaft 16' connected to the flaw detection section 1 are attached to both sides of the piston, respectively. There is.

Therefore, the rotational and axial movement of the transmission shaft 16, indicated by the arrow in the figure, is transmitted to the transmission shaft 16' via the piston 18, as indicated by the arrow. At this time, piston 1
8 can move freely within a cylinder 17 constituted by a ball bearing, and the cylinder 17 is held in its position within the tube section 8' by a reaction brush 19 in contact with the tube section 8'. As a result, even if the flexible portion 9' of the insertion guide shaft 9 is bent, the slide core 6 is guided by the hollow nozzle 8 as a guide member, and the movement of the flaw detector in the rotational direction and shaft feeding direction is smooth and accurate. It is designed to be transmitted to the side.

The present embodiment is constructed as described above, and in order to use it, first insert the nozzle 8 and the insertion guide shaft 9 connected thereto into the header whitening through the header inspection hole (not shown), and then The nozzle 8 is pressed against the end 10 of the pipe section to be inspected.

Next, from the open end of the insertion guide shaft 9, the flaw detection section 11, the ball-attached cable 7, the rotation motor 3, the shaft feed fine movement mechanism 5,
Insert the shaft feed motor 4 etc. into the insertion guide shaft 9. A magnet 1 fixed to the outside of the insertion guide shaft 9 indicates that the flaw detection part 1 has been inserted to the position of the welded part 11 between the nozzle head and the pipe to be detected.
The positioning is performed by detecting the magnetism of 2 with the position detector 13.

As shown in FIG. 1, at this time, the flaw detection section 1 and alignment tool 2
has passed through the insertion guide shaft 9 and the nozzle 8 and is inserted into the tube 21 to be flaw-detected, and the flaw-detecting part 1 occupies a predetermined position within the tube by the centering tool 2.

When the flaw detection section 1 is set in this state, the insertion guide shaft 9,
Water is filled up to the nozzle 8 and around the welded part 11 of the pipe section.

Next, the shaft feed motor 4 is rotated forward. Along with this,
The ball screw 14 attached to the motor 4 rotates,
The shaft feed nut 1 of the shaft feed fine adjustment mechanism 5 together with the rotary motor 3
5 moves forward. This movement advances the flaw detection section 1 via the transmission shaft 16, slide core 6, and transmission shaft 16'.

The feed amount at this time is converted from the rotation speed of the shaft feed motor 4. After moving forward by a predetermined amount, the shaft feed motor 4 stops. At the same time, the rotation motor 3 is rotated to rotate the flaw detection section 1 in the circumferential direction. The rotation angle at this time is the rotation motor 3d.
Since it is determined from the rotation speed and gear ratio, if the gear ratio is kept constant, it can be converted from the rotation speed of the rotation motor 3.

During this movement, since the flaw detection part 1 is held in its position within the tube by the centering tools 2, 2, the flaw detection part 1 is moved without leaving the center of the tube 21. Flaw detection section 1
After rotating by a certain angle, the rotation motor 3 stops. At the same time, the feed motor 4 is reversely rotated to move the flaw detection section 1 backward in the opposite direction. After retracting by a predetermined amount, the rotation motor 3 is again rotated by a predetermined angle in the same direction as the previous time, and the flaw detection section 1 is rotated in the circumferential direction in the same manner as the previous time. The flaw detection section 1 is then automatically operated continuously in the same manner as shown in Fig. 2.
A longitudinal rectangular scan of the inside of the tube 21 is carried out. As a result, the welded portion 11 is detected by ultrasonic waves emitted from the probe of the flaw detection section 1 from the inside of the tube 21 to the outside of the tube.

In this embodiment, flaw detection can be performed from inside the pipe 21 at the welded part between the pipe and the nozzle joint, and additional work such as removal of the conventional heat insulating material, polishing of the welded part, or restoration of the heat insulating material after flaw detection is performed. does not require.

In addition, when performing flaw detection, the rotation motor 3 must be
and the flaw detection section 1 by rotating the shaft feed motor 4.
can perform the desired movement and perform reliable flaw detection.

In addition, in the slide core 6, the transmission shirt) 16
．． 16' and the piston 18 that connects the two are guided by the tube part 8' of the nozzle 8 and can freely rotate and move, so that the transmitted rotation and axial movement can be transferred smoothly and accurately to the flaw detection part l. I can tell you.

Furthermore, the flaw detection section 1 is guided by centering tools 2, 2 and the tube 2
1, its position with respect to the interpipe 21 can be accurately maintained.

In addition, in this embodiment, in addition to the vertical rectangular scanning shown in FIG. 2, it is also possible to scan an arbitrary trajectory by operating the rotation motor 3 and the axis feed motor 4 as appropriate.

In the above embodiment, the welded portion of a pipe attached to a nozzle stub is tested for flaws, but the present invention is not limited to this, and can be widely applied to detecting flaws from the inside of a pipe or the like.

〔Effect of the invention〕

As described above, according to the present invention, the flaw detection part can be accurately and smoothly moved inside a pipe or the like from the outside, and reliable flaw detection has become possible. Further, this eliminates the need for removal of the heat insulating material of the header, polishing work, etc., and the cost of flaw detection can be reduced. Furthermore, flaw detection in narrow areas can be carried out easily and the reliability of flaw detection can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of vertical rectangular scanning showing the movement of the probe of the same embodiment, and Fig. 3 is an explanatory diagram of the slide core of the same embodiment. be. DESCRIPTION OF SYMBOLS 1... Flaw detection part, 2... Alignment tool, 3... Rotation motor, 4... Transport simulator, 5... Axis feed fine movement mechanism,
6...Slide core, 7...Ball cable, 8.
... Nozzle, 8'... Nozzle pipe section, 9... Insertion guide, 14... Ball screw, 15... Transport nut, 16.16'... Transmission shaft, 17... Cylinder , 18...Piston, 19...Reaction force brush.

Claims (1)

[Claims] A flaw detection section equipped with a probe, a rotation motor of the flaw detection section and a shaft feed motor of the flaw detection section connected in series to the flaw detection section, respectively.
A slide core that is disposed between the flaw detection section and both motors and transmits the rotation and shaft feeding movements of the shaft rotation motor and shaft feed motor to the flaw detection section, and a guide that guides the slide core inside the slide core. An interpolation type ultrasonic flaw detection device characterized by comprising a member.