JP2003254945A - Corrosively thinned thickness measuring and inspecting device for steel pipe, and its using method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure and inspect automatically corrosively thinned thickness of a steel pipe from an inner face part of the steel pipe by utilizing ultrasonic wave in the state where a reinforcing plate is attached to the end of the steel pipe or the mouth thereof is contracted. <P>SOLUTION: Shrunk balloon bodies are attached to a support shaft to sandwich a detection head for mounting an ultrasonic probe, and are inserted into a pipe. Then, the balloon bodies are filled with air through a support shaft inner diameter hole to be inflated, filled with water which is a flaw detection medium through a hose inserted beforehand into a steel pipe inner diameter face upper position to form a detection mechanism part, and pulled by a wire. The air is introduced or sucked as the need arises, for smooth movement/ transfer of the detection mechanism part, and to enable corrosively thinned thickness measuring inspection automatically from the pipe inner face part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

[Meaning of corrosion thinning inspection] From the viewpoint of safety measures and resource saving, the corrosion thinning measurement inspection of steel pipe structures in use is of great value. For example, for steel pipes of steel pipe towers in use,
If the amount of corrosion-reduced metal is large, it is possible to take precautionary measures in advance to prevent accidents. On the other hand, if the amount is small, a large resource-saving value can be obtained by using information on life extension. Becomes The present invention is an apparatus for automatically measuring and inspecting the wall thickness / corrosion thinning of a steel pipe building in use from the inner surface of the pipe, and a method of using the same.

[0002]

2. Description of the Related Art Generally, a small diameter steel pipe is used for a heat exchanger, and an automatic ultrasonic flaw detector is applied to this maintenance inspection. Fill the entire inner diameter of the pipe with water, insert a pencil-shaped pig that is loaded with an ultrasonic probe and a probe, and connect a small-diameter motor that rotates in the circumferential direction of the inner diameter into this water. It is a system that is installed and continuously conveyed, and automatically performs corrosion thinning inspection. On the other hand, an automatic ultrasonic flaw detector has been partially developed for maintenance inspection of large-diameter steel pipes such as pipelines of petroleum complex. The structure is a system for carrying and inspecting a bullet-shaped pig having a large number of ultrasonic probes arranged in the circumferential direction by towing or introducing air from the pipe end. However, in any of the methods, it is premised that there is no deformation of the pipe shape such as attachment of obstacles such as a reinforcing plate at the end of the pipe when inserting the pig, and the shape of the pipe, such as a steel pipe tower. When a cross-shaped reinforcing plate is attached, neither device is applicable. Therefore, the corrosion thinning inspection of the steel pipe with these reinforcing plates attached or narrowed is
In steel pipe towers, measurement and inspection have been performed by a method of manually detecting a part of the steel pipe from the outer surface by an ultrasonic contact method. However, manual flaw detection is labor-intensive, and if it is premised on work at a high place such as a steel pipe tower, there are major safety problems, and the flaw detection range of steel pipes must be locally limited. Even in the case of manual flaw detection, it was very rarely applied to the corrosion thinning inspection of steel pipes.

[0003]

The methods of filling the entire inside of the steel pipe with water or continuously supplying water to the ultrasonic probe require an extremely large-scale device and the diameter of the steel pipe increases. It becomes more prominent. Furthermore, when a reinforcing plate is attached to the end or when measuring and inspecting a narrowed steel pipe from the inner surface of the pipe, it is impossible to insert the pig attached with the probe, that is, the detection head itself in the conventional method. For,
It was difficult to carry out automatic inspection.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a reduced balloon body is attached to a support shaft so as to sandwich a detection head mounted with an ultrasonic probe, and after being inserted into a tube, air is blown through a bore of the support shaft. A mechanism that fills the body and inflates it to bring it into close contact with the inner diameter surface of the pipe, fills the water of the flaw detection medium from the hose previously inserted in the upper position of the inner diameter surface of the steel pipe, and seals and holds it in the local range near the detection head part. An apparatus for measuring and inspecting corrosion thinning, which is provided, and a measuring and inspecting method using the apparatus.

Further, according to the present invention, the above-mentioned mechanism, that is, the balloon body expanded in the tube, and the flaw detection section composed of the detection head and the water of the flaw detection medium sealed between the elements are pulled by a wire, and if necessary, the tube end. A device that smoothes the movement / transportation of the detection mechanism unit by introducing or sucking air from the pipe, and automatically enables corrosion thinning measurement inspection from the inner surface of the pipe, and a measurement inspection method using the device. Is.

[0006]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 exemplifies a mechanism that minimizes the amount of water in the flaw detection medium and stably supports the detection head mounted with the ultrasonic probe. If necessary, a balloon body that can be easily enlarged / reduced and has the strength to hold the ultrasonic detection head part is attached in front of and behind the ultrasonic detection head, and the water of the flaw detection medium is trapped in this gap. It is a mechanism.
For the operation, first, the reduced balloon body is attached to the support shaft with the detection head interposed therebetween. For steel pipes with a reinforcing plate,
The steel pipe narrowed to the shape of the reinforcing plate is reduced to a size that can be inserted in advance according to the shape of the narrowed mouth. Next, these integrated flaw detection parts are inserted into the tube, and after passing through the reinforcing plate or the mouth-neck part, the balloon body is filled with air through the hollow hole of the support shaft to expand and adhere to the required size. . After that, water as a flaw detection medium is injected from a hose previously inserted in the upper portion of the inner diameter surface of the pipe in the detection portion. By using this mechanism, it is possible to perform corrosion thinning measurement inspection from inside the steel pipe.

As shown in FIG. 2, a detection head portion held by two balloons and a detection mechanism portion composed of water as a flaw detection medium hermetically held in the gap are pulled by a wire to Accordingly, by introducing or sucking air from the pipe end portion using a compressor or a suction pump, the movement and conveyance of the detection mechanism portion is smoothly performed, and a corrosion thinning measurement test is performed.

FIG. 3-1 (left diagram) compares the sizes of the steel pipe provided with the I-shaped reinforcing plate to be measured and the detection mechanism in the steel pipe, and FIG. 3-1 (right diagram). Shows a comparison of the sizes of a steel pipe provided with a cross-shaped reinforcing plate to be measured and a detection mechanism in the steel pipe. The detection mechanism has a small and compact structure shown in FIG.

Further, FIG. 3-2 (left diagram) illustrates a fan-shaped detection mechanism to which the probe is attached. Arrange the required number of probes on the fan-shaped probe mounting jig, and inject ultrasonic waves almost perpendicularly to the probe position and the inner diameter surface of the steel pipe according to the required flaw scanning pitch in the pipe circumferential direction in advance. Adjust the angle and insert. When increasing the flaw detection area, a plurality of the probe attachment jigs are arranged in the longitudinal direction of the pipe, and a required number of probes are attached to each jig. Figure 3-2 (right) shows
An example is shown in which the detection mechanism is located at the bottom of the steel pipe. Since the fan-shaped detection mechanism with the probe attached is a structure that is free to move in the circumferential direction around the support shaft as a base point, when the detection head separates from the end reinforcing plate or the mouth stop after insertion, the detection head is moved by its own weight. The central part is located at the bottom part of the steel pipe.

In this way, the thinning measurement inspection result is obtained by the ultrasonic wave reception information of each probe and the position information of each probe into which the feed speed of the detection head is input, thereby reducing the corrosion at each site. It is a system that displays the amount of meat and displays a map of the corrosion thinning inside the pipe.

[0011]

EFFECTS OF THE INVENTION According to the present invention, it is possible to easily carry out a steel pipe corrosion thinning measurement inspection from the inner diameter portion of the pipe, and to attach a reinforcing plate to the end portion of the steel pipe and to automatically check a narrowed steel pipe, which has been particularly difficult in the past. Inspection is now possible. By applying this device, important information on safety measures and strength judgment of steel pipe structures can be obtained and great effects can be expected.

[Brief description of drawings]

FIG. 1 is a detection mechanism of a steel pipe corrosion thinning inspection device according to the present invention.

FIG. 2 is a front view of a steel pipe corrosion thinning inspection device according to the present invention.

3-1 (left) is a size comparison between a steel pipe provided with an I-shaped reinforcing plate and a detection mechanism in the steel pipe, FIG.
-1 (right figure) is a size comparison between a steel pipe provided with a cross-shaped reinforcing plate and a detection mechanism in the steel pipe.

FIG. 3-2 is a fan-shaped detection mechanism to which the probe is attached. Fig. 3-2 (right) shows the detection mechanism located on the bottom surface of the steel pipe. It is a detailed view of the detection head of the steel pipe corrosion thinning inspection device according to the present invention.

[Explanation of symbols]

1. Steel pipe 2. (Medium) water 3. Detection head 4. Probe 5. Balloon body (oval case) 6. Support shaft 7. Air insertion hole 8. Towing machine 9. Compressor container 10. Reinforcement plate 11. wire 12. Steel pipe inner diameter center 13. Oscillator 14. Mounting jig B probe (group) 15. Mounting jig A 16. Mounting jig B

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G047 AA07 AB01 BA03 BB05 BC11                       CA01 DB05 DB12 DB18 EA14                       GA02 GA03 GA14 GB04 GE02                       GE04 GE05 GH19 GJ09 GJ12

Claims (3)

[Claims] 1. A corrosion thinning measurement / inspection mechanism, in which a balloon body is loaded so as to sandwich an ultrasonic probe-mounted detection head inserted in an inner diameter portion of a pipe, and water for a flaw detection medium is hermetically held therebetween. A device to measure and inspect corrosion thinning from the inner surface of the pipe. 2. The corrosion-thinning measurement / inspection device according to claim 1, wherein two balloon bodies inserted in the inner diameter of the pipe and a detection head and an ultrasonic detection medium having an ultrasonic probe mounted therebetween are provided. Corrosion from the inner surface of the pipe by pulling the detection mechanism integrated with water and pulling it with a wire and smoothing the movement and transportation of the detection mechanism by introducing or sucking air from the end if necessary. A device for measuring and inspecting thinning. 3. An apparatus for measuring and inspecting corrosion thinning from the inner surface portion of the pipe according to claim 1 or 2, which is a method for measuring and inspecting corrosion thinning from the inner surface portion of the pipe using the apparatus.