JP2013174531A - Ultrasonic inspection device and inspection method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic inspection device which is compact, light-weight, and easy to be handled even in a narrow space, capable of reducing an inspection time, and also capable of performing an inspection with high accuracy.SOLUTION: In an ultrasonic inspection device 10A, rollers 14 and 16 are provided at the front and rear parts of a body block 12, respectively. A transfer block 18 is provided vertically slidably with respect to the body block 12. To the transfer block 18, a spring force directed toward an external surface of a nozzle stub 102 is imparted by a coil spring 22. On the transfer block 18, a two-vibrator probe 20 is provided, and an encoder 24 is provided for detecting a position of the ultrasonic inspection device 10A. A worker mounts the ultrasonic inspection device 10A on the nozzle stub 102, and inspects presence/absence of a thin-wall part r by shifting the ultrasonic inspection device 10A in a circumferential direction of the nozzle stub 102.

Description

  The present invention relates to a simple manual ultrasonic inspection apparatus suitable for inspecting densely arranged pipes such as boiler evaporator tubes, and an inspection method thereof.

  As shown in FIG. 6, a nozzle 102 is connected to a boiler header (header) 100 via a welded portion w. Corrosion occurs on the inner surface of the base portion of the nozzle 102 due to the accelerated flow of steam flowing inside the nozzle, and a thinned portion r is generated. Therefore, thickness measurement is performed using an inspection apparatus using ultrasonic waves. FIG. 7 shows an example in which the inspection result of the base of the nozzle base using the ultrasonic inspection apparatus is displayed on the display device. From FIG. 7, it can be seen that the thinned portion r is locally generated on the inner surface of the nozzle.

  FIG. 8 shows a case where fixed point measurement is performed in the circumferential direction of the nozzle by the ultrasonic probe 104 (in FIG. 8, four positions at 90 ° intervals). However, this inspection method has a problem that the maximum damage position cannot be specified. Therefore, in order to specify the maximum damage position, an inspection over the entire circumference of the pipe is necessary.

  Patent Document 1 discloses an ultrasonic flaw detector that detects a defect in piping. This device is provided in a circumferential ring guide portion detachably attached to the outer surface of the pipe, a circumferential ring moving along the circumferential ring guide portion, and provided in the circumferential ring in the longitudinal direction of the pipe. The arm includes an extended arm, a probe moving unit that moves along the arm, and an ultrasonic probe provided in the probe moving unit.

  In this apparatus, the orbiting ring can be moved in the circumferential direction of the pipe along the circling ring guide part, and the probe moving part can be moved along the arm in the longitudinal direction of the pipe. For this reason, the probe can be moved over the entire area of the pipe surface, so that the entire area in the circumferential direction of the pipe can be measured, not fixed point measurement.

Japanese Patent Application Laid-Open No. 07-181171

  Since a large number of nozzles are connected in close contact with the boiler header, there is not enough space around the base of the nozzle to allow an operator to inspect with sufficient margin. Therefore, in manual inspection performed by an operator holding an ultrasonic probe, it is not easy to stably position and scan the probe on the pipe surface. Therefore, the inspection must be performed in an unstable state, and it is not easy to obtain an accurate inspection result.

  The ultrasonic inspection apparatus disclosed in Patent Document 1 is a large-scale apparatus that requires a plurality of driving devices for driving the circulation ring and the probe moving unit, and is therefore suitable for inspection of a large-diameter tube. However, it is not suitable for inspection of small diameter pipe groups arranged in a small space such as a boiler nozzle. Further, since it is necessary to attach the circular ring guide part to the outer surface of the pipe to be inspected, it takes time to attach and remove the circular ring guide part. Therefore, there is a problem that it takes an enormous amount of time to inspect a large number of tube groups.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and has an object to realize an ultrasonic inspection apparatus that is small, lightweight, easy to handle even in a narrow space, can reduce inspection time, and can perform high-precision inspection. To do.

  In order to achieve such an object, the ultrasonic inspection apparatus of the present invention is provided with rollers at the front and rear portions of the main body block, and the main body block is arranged to face the surface to be inspected when these rollers contact the surface to be inspected. And it becomes possible to run. The main body block is provided with an ultrasonic probe that oscillates ultrasonic waves with respect to the surface to be inspected and receives reflected waves to detect damage and defects of the inspected object. In this way, the operator can stably arrange the main body block with respect to the surface to be inspected by simply arranging the inspection device so that the roller is in contact with the surface to be inspected, and moving the inspection device, thereby enabling inspection. Therefore, it is easy to operate, and since fixed point measurement is not possible and continuous measurement is possible, the maximum damage site can be specified.

  The ultrasonic probe is provided so as to be able to advance and retreat with respect to the main body block, and an urging force toward the surface to be inspected is applied by the urging means. Therefore, regardless of whether the surface to be inspected is a flat surface or a curved surface, the ultrasonic probe can be in close contact with the surface to be inspected, so that the inspection performance of the ultrasonic probe can always be maintained well.

  Since the inspection apparatus according to the present invention has a configuration in which a roller and an ultrasonic probe are simply attached to a main body block, it can be reduced in size and weight, and therefore, inspection can be performed even in a narrow space. Moreover, unlike patent document 1, it is not necessary to attach the guide for circling a main body block, and attachment and removal time of this guide are not required. Therefore, the inspection time can be shortened.

  In the present invention, a position detection sensor for detecting the travel distance of the main body block may be provided, and the position of the main body block may be detected from the detection value of the position detection sensor. As a result, information obtained by linking the inspection position of the surface to be inspected and the inspection result can be obtained. Therefore, the position of the defect on the surface to be inspected can be accurately grasped.

  In the present invention, the roller may be attached to an arm that is pivotally supported by the main body block so as to be able to rotate in a direction of moving back and forth toward the surface to be inspected. Accordingly, the relative position between the roller and the ultrasonic probe can be freely adjusted, so that the degree of freedom of the shape of the surface to be inspected can be further expanded. That is, regardless of whether the surface to be inspected is a flat surface or a curved surface, the ultrasonic probe can be kept in close contact with the surface to be inspected even on a curved surface having an arbitrary radius of curvature. More preferably, an urging means for applying an urging force for urging the arm to the surface to be inspected may be provided. As a result, the roller can always be arranged at a position close to the surface to be inspected.

  In the present invention, the object to be inspected constituting the surface to be inspected may be made of a magnetic material, and the roller may have a magnetic force generating function. Thus, when the object to be inspected is made of a magnetic material, the roller is attracted to the surface to be inspected by magnetic force, so that the body block can be stably held on the surface to be inspected. Therefore, the operation of the main body block can be facilitated.

  Further, the inspection method of the ultrasonic inspection apparatus of the present invention is a surface of a pipe having a circular arc shape to be inspected, and when the ultrasonic inspection apparatus of the present invention includes the position detection sensor, It is a method for inspecting for defects or thinning. The method of the present invention includes an inspection process in which an ultrasonic inspection apparatus is run in the circumferential direction of a pipe and inspected a plurality of times by changing the position in the axial direction of the pipe, and piping among the inspection information obtained in the inspection process. Inspection information processing step for connecting inspection information in the specific circumferential direction to obtain inspection information in the pipe axis direction in the specific circumferential direction. As a result, it is possible to grasp a defect in the pipe axis direction or a distribution of thinning in a specific circumferential direction of the pipe.

  According to the ultrasonic inspection apparatus of the present invention, it is possible to reduce the size and weight, and it is easy to operate in a narrow space, and it is possible to specify the maximum damage site without performing fixed point measurement. In addition, since the inspection time can be shortened, inspection of a large number of tube groups arranged in a narrow space can be performed in a short time. In addition, since the ultrasonic probe can be brought into close contact with the surface to be inspected without being restricted by the shape of the surface to be inspected, high inspection performance can be maintained.

  According to the inspection method of the present invention, the position of the ultrasonic inspection apparatus is detected by the position detection sensor, and a plurality of inspection results having different axial directions in the specific circumferential direction of the pipe are joined together, whereby the pipe axial direction in the specific circumferential direction Inspection information can be obtained.

1 is a perspective view of an ultrasonic inspection apparatus according to a first embodiment of the present invention. 1 is a front view of an ultrasonic inspection apparatus according to a first embodiment. It is a perspective view which shows the test | inspection condition of the boiler nozzle using the ultrasonic inspection apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows the screen of the test result obtained in 1st Embodiment. It is a schematic diagram which shows the ultrasonic inspection apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the thinning condition of a bolt nozzle. It is a schematic diagram which shows the screen of the ultrasonic test result of a boiler nozzle. It is sectional drawing which follows the AA line in FIG.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. 1 and 2, the ultrasonic inspection apparatus 10 </ b> A according to the present embodiment is used for inspecting a thinning state that occurs on the inner surface of the base portion of the nozzle 102 connected to the header 100 of the boiler. The ultrasonic inspection apparatus 10 </ b> A includes a main body block 12. Therefore, the lower surface 12a of the main body block 12 has a curved surface similar to the arc-shaped surface to be inspected on the surface of the nozzle.

  Rollers 14 and 16 are rotatably provided at front and rear portions of the main body block 12 in the moving direction. The shafts 14 a and 16 a of the rollers 14 and 16 are arranged in a direction orthogonal to the moving direction with respect to the main body block 12. The rollers 14 and 16 are pivotally supported so as to be rotatable about the shafts 14a and 16a. The nozzle 102 is made of a steel pipe such as carbon steel and is a magnetic body. On the other hand, the rollers 14 and 16 are composed of permanent magnets. Therefore, when the worker P places the ultrasonic inspection apparatus 10 </ b> A on the outer surface of the nozzle 102, an adsorption force is generated between the rollers 14 and 16 and the nozzle 102. Therefore, the operator can stably hold the ultrasonic inspection apparatus 10A on the outer surface of the nozzle, and the operation becomes easy.

  A moving block 18 is provided at the center of the main body block 12 so as to be slidable up and down with respect to the main body block 12. That is, a concave groove 12b is provided in the vertical direction in the center of the main body block 12, and a sliding portion 18a integrated with the moving block 18 is slidably fitted into the concave groove 12b. A dual element probe 20 is attached to the lower part of the moving block 18. The dual transducer probe 20 is a probe in which an ultrasonic oscillation unit and a reception unit are divided, and the reception unit is not affected by the transmission pulse oscillated from the oscillation unit. Thickness can be measured with high accuracy.

  The moving block 18 is attached to the main body block 12 via a coil spring 22, and the moving block 18 receives a spring force directed downward from the coil spring 22. Therefore, the dual transducer probe 20 can always be brought into close contact with the outer surface of the nozzle 102 by the spring force of the coil spring 22 regardless of the diameter of the nozzle 102 and the curvature of the outer surface.

  An encoder 24 is provided at the rear of the main body block 12. A first arm 26 is rotatably provided on the main body block 12 via a shaft 26 a, and an encoder 24 is attached to the tip of the first arm 26. Further, a second arm 28 is provided between the first arm 26 and the main body block 12 so as to be rotatable via a shaft 28a. The encoder 24 is held at a position close to the nozzle 102 by the second arm 28.

  The operator P carries the ultrasonic inspection apparatus 10A having such a configuration to the header 100 and places it on the base of the nozzle 102 as shown in FIG. At this time, the rollers 14 and 16 are brought into contact with the outer surface of the nozzle 102 and placed on the outer surface of the nozzle 102 so that the axial direction of the rollers coincides with the axial direction of the nozzle 102. Next, the worker P inspects the thinning state of the nozzle 102 by oscillating ultrasonic waves from the probe 20 while moving the ultrasonic inspection apparatus 10 </ b> A in the circumferential direction a of the nozzle 102. A cable 38 is connected to the dual transducer probe 20, and the detection signal of the dual transducer probe 20 is also sent to the signal processing device 40 via the cable 38.

  When the main body block 12 is moved, the worker P presses the first arm 26 so that the encoder 24 contacts the outer surface of the nozzle 102. Thereby, the position of the main body block 12 can be detected by the encoder 24. The detection signal of the encoder 24 is also sent to the signal processing device 40 via the cable 38. With these operations, it is possible to inspect the circumferential thinning state of the inner surface of the nozzle, and to display the inspection result as shown in FIG. 7 on the display unit of the signal processing device 40.

  Next, a method for inspecting the axial thinning state of the inner surface of the base of the nozzle base using the ultrasonic inspection apparatus 10A will be described. The worker P performs an operation of moving the ultrasonic inspection apparatus 10 </ b> A in the circumferential direction of the nozzle 102 and measuring it a plurality of times while changing the axial position of the nozzle 102. Next, inspection information in a specific circumferential direction is selected from the circumferential positions of the ultrasonic inspection apparatus 10 </ b> A obtained by the encoder 24. The selected inspection information in the specific circumferential direction is connected to create the graph shown in FIG. 4 and displayed on the display unit of the signal processing device 40. With this inspection method, the thickness reduction distribution in the axial direction of the nozzle 102 in the specific circumferential direction can be detected, and the thickness reduction portion r can be grasped.

  According to this embodiment, the main body block 12 is placed on the surface of the nozzle with the rollers 14 and 16 facing downward, and the worker P can perform the inspection only by moving the ultrasonic inspection apparatus 10A. Therefore, the operation is easy, the fixed point measurement is not performed, and the thinning state of the nozzle 102 can be detected on the continuous surface in the circumferential direction. Therefore, it can identify without missing the maximum thinning part. Further, the dual transducer probe 20 is provided so as to be able to advance and retreat relative to the main body block 12 with respect to the nozzle 102, and the spring force is urged toward the nozzle 102 by the coil spring 22. Even if the curvature of the outer surface changes, it can always adhere to the nozzle surface. Therefore, the detection performance can always be kept high.

  Further, since the ultrasonic inspection apparatus 10A has a simple configuration in which the main body block 12 is provided with the rollers 14, 16, the dual transducer probe 20, the encoder 24, and the like, it can be reduced in size and weight. It is possible to operate even in a narrow space where the nozzles 102 are densely arranged and easy to handle. In addition, since it is not necessary to attach a guide or the like for moving the ultrasonic inspection apparatus 10A on the surface of the nozzle, the inspection time can be shortened, and much time is not required for inspection of the nozzles 102 arranged in large numbers.

  Moreover, since the encoder 24 is provided and the position information of the ultrasonic inspection apparatus 10A can be obtained from the encoder 24, information obtained by linking the inspection position and the inspection result can be obtained. Therefore, the character position of the thinned portion r can be specified. Further, since the rollers 14 and 16 are composed of permanent magnets, an attractive force can be generated between the rollers 14 and 16 and the nozzle 102 made of a magnetic material. Therefore, the ultrasonic inspection apparatus 10A can be stably held on the surface of the nozzle.

  Furthermore, as described above, the axial thinning state of the nozzle 102 in the specific circumferential direction can be detected by changing the axial position of the nozzle 102 a plurality of times.

  In the present embodiment, an urging unit for bringing the encoder 24 into contact with the nozzle surface may be provided. This eliminates the need for the operator to manually hold the encoder 24 against the nozzle surface. For example, the second arm 28 is composed of a coil spring, and a spring force is applied to urge the encoder 24 on the nozzle surface side. Further, the rollers 14 and 16 may be made of a rubber tire having elasticity.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram schematically showing the ultrasonic inspection apparatus 10B of the present embodiment. Arms 30 and 32 are provided at the front and rear of the main body block 12. The arm 30 is attached to the main body block 12 via a shaft 30a so as to be rotatable in the arrow c direction. A spring 34 is provided around the shaft 30a. The spring force of the spring 34 biases the arm 30 toward the nozzle 102.

  The arm 32 is attached to the main body block 12 so as to be rotatable in the direction of the arrow d via a shaft 32a. A spring 36 is provided around the shaft 32 a, and the spring force of the spring 36 biases the arm 32 toward the nozzle 102. The roller 14 is rotatably attached to the tip of the arm 30, and the roller 16 is rotatably attached to the tip of the arm 32.

  Other configurations are the same as those of the ultrasonic inspection apparatus 10A of the first embodiment. That is, the dual transducer probe 20 is attached to the main body block 12 via the coil spring 22 so as to be able to advance and retreat with respect to the nozzle 102. The spring force of the coil spring 22 urges the probe 20 in a direction toward the nozzle 102. Similarly to the first embodiment, the encoder 24 (not shown) is also mounted on the main body block 12.

  In this embodiment, the rollers 14 and 16 are attached to the arms 30 and 32 and can move in a direction approaching or separating from the nozzle 102, so that the nozzle having a wider range of caliber or radius of curvature than that of the first embodiment. The dual transducer probe 20 can be brought into close contact with 102.

  According to the present invention, it is possible to realize an ultrasonic inspection apparatus that is small, lightweight, easy to handle even in a narrow space, can reduce inspection time, and can perform high-accuracy inspection.

10A, 10B Ultrasonic inspection apparatus 12 Main body block 12a Lower surface 12b Concave groove 14, 16 Roller 14a, 16a, 26a, 28a, 30a, 32a Axis 18 Moving block 18a Sliding part 20 Dual transducer probe 22 Coil spring 24 Encoder 26 First arm 28 Second arm 30, 32 Arm 34, 36 Spring 38 Cable 40 Signal processing device 100 Heading 102 Tubular base 104 Ultrasonic probe P Worker r Thinning part w Welding part

Claims (5)

A main body block disposed opposite to the surface to be inspected;
A roller provided at a front portion and a rear portion of the main body block, in contact with the surface to be inspected, and disposed so as to face the surface to be inspected and capable of traveling;
An ultrasonic probe that is provided in the main body block so as to be movable back and forth with respect to the surface to be inspected, oscillates ultrasonic waves with respect to the surface to be inspected, and receives the reflected waves;
An ultrasonic inspection apparatus comprising: an urging unit that applies an urging force toward the surface to be inspected with respect to the surface to be inspected.
Ultrasonic inspection device.   The ultrasonic inspection apparatus according to claim 1, further comprising a position detection sensor that detects a travel distance of the main body block, wherein the position of the main body block can be detected from a detection value of the position detection sensor.   The ultrasonic inspection apparatus according to claim 1, wherein the roller is attached to an arm that is pivotally supported by the main body block so as to be able to rotate back and forth toward a surface to be inspected.   The ultrasonic inspection apparatus according to claim 1, wherein an object to be inspected constituting an inspection surface is made of a magnetic material, and the roller has a function of generating a magnetic force. In the method for inspecting a defect or a thinning state of the pipe using the ultrasonic inspection apparatus according to claim 2, wherein the surface to be inspected is a surface of the pipe having an arc shape.
An inspection process in which the ultrasonic inspection apparatus is placed on the surface of the pipe and moved in the circumferential direction of the pipe for inspection, and the inspection is performed a plurality of times while changing the axial position of the pipe;
Ultrasonic inspection characterized by comprising an inspection information processing step for joining inspection information in a specific circumferential direction of piping among inspection information obtained in the inspection step and obtaining axial inspection information in the specific circumferential direction Device inspection method.

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