JP2001074714A - Ultrasonic inspection method for pipe and liquid sealing device used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform an inspection operation by a constitution wherein a liquid inside a pipe is made to communicate with a liquid inside a liquid tank through a communication pipe which is installed so as to communicate from the lower end of the pipe, the level height of the liquid tank is adjusted and a level inside the pipe is set at a prescribed height. SOLUTION: A plurality of pipes 1 are held by a pipe plate 2. The lower end of one pipe 1 as an object to be inspected is closed by a liquid sealing device 3. One end of a communication pipe 4 is connected to the liquid sealing device 3, and the other end of the communication pipe 4 is connected to the bottom part of a liquid tank 5. The communication pipe 4 is a tube which is made of a flexible material such as a plastic material, a rubber material or the like. Consequently, the height of the liquid tank 5 can be adjusted arbitrarily. A liquid 6 such as water, methyl alcohol or the like is put into the pipe 1 and the liquid tank 5. After the level of the pipe 1 is set in a prescribed position, a prove 7 is immersed in the liquid inside the pipe 1 so as to perform an ultrasonic inspection. Thereby, even when a measuring implement is inserted into, and pulled out from, the pipe, the liquid does not overflow from the pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic inspection method for inspecting a pipe for thinning or cracks generated by an ultrasonic immersion method, and a liquid stopper used for the method.

[Prior art]

As shown in FIG. 5, a plurality of pipes 50 are arranged side by side in a catalyst filling tube of a reactor, a heat transfer tube of a heat exchanger, and the like, and both ends thereof are fixed by tube sheets 51. Since the thickness of these pipes 50 may be reduced during use, the thickness of the pipes is periodically inspected.

[0003] Ultrasonic water immersion, which can obtain high inspection accuracy, is widely used for wall thickness inspection of pipes. In this method, an ultrasonic probe 53 is placed in a pipe 50 into which water 52 has been injected.
And ultrasonic waves transmitted directly or from the ultrasonic probe 53 in the axial direction of the pipe 50 are reflected by an acoustic mirror (not shown), and vertically incident on the inner surface of the pipe 50. It is to let. Then, a method of measuring the difference between the propagation distance of the echo S from the normal inner surface of the pipe 50 without wall thinning and the echo S 'from the wall thinning portion as the wall thinning amount, and the ultrasonic wave in the pipe wall thickness. A method of measuring the propagation time and converting it to a thickness is used. The lower end of the pipe 50 is previously closed with a water stopper 54 such as a rubber stopper.

[0004]

In order to inspect the pipe 50 by the above-mentioned ultrasonic water immersion method, first, water 52 is injected into the pipe 50. In order to perform the inspection over substantially the entire length of the pipe 50, it is necessary to substantially fill the inside of the pipe 50 with water 52. Therefore, if the amount of water 52 injected into the pipe 50 is large, when a thickness measuring jig (hereinafter referred to as a measuring jig) to which the ultrasonic probe is attached is inserted, the water 5
2 may overflow from the pipe 50 and travel along the tube sheet 51 into another adjacent pipe 50.

[0005] However, when the pipe 50 is used as a catalyst-filled pipe of a reactor, if the water overflowing from the pipe 50 enters the adjacent pipe 50 filled with the catalyst, it adversely affects the charged catalyst. Further, even when the pipe 50 is used as a heat exchanger tube of a heat exchanger, if a treatment such as detoxification or cleaning of all the pipes is not performed with the opening of the heat exchanger, the physical properties of the fluid in the pipe cause May dislike contact with water.

Therefore, when inserting the measuring jig, it is necessary to carefully inject water so that water does not overflow from the pipe 50. However, even if the measuring jig is slightly inserted in the pipe axial direction, the diameter of the measuring jig is small. In a small pipe 50, there is a possibility that the water level rises sharply and the water overflows. In addition, when the measuring jig is pulled out, water does not remain on the upper part of the pipe 50 and the inspection cannot be performed by the ultrasonic water immersion method. For these reasons, the inspection work has become very complicated and difficult.

Accordingly, a main object of the present invention is to provide an ultrasonic inspection method for a pipe which suppresses a large rise in liquid level even when a liquid such as water is injected into the pipe, thereby facilitating the inspection work. To provide. Another object of the present invention is to
An object of the present invention is to provide a liquid stopping device suitable for use in the ultrasonic inspection method.

[0008]

According to an ultrasonic inspection method of the present invention for solving the above-mentioned problems, an ultrasonic probe is inserted into a pipe into which a liquid has been injected to inspect the pipe. The liquid in the pipe is communicated with the liquid in the liquid tank via a communication pipe extending from the lower end of the pipe, and the liquid level in the pipe is adjusted to a predetermined level by adjusting the liquid level in the liquid tank. It is characterized by the following.

As described above, the liquid in the pipe and the liquid in the liquid tank are communicated through the communication pipe. Therefore, when the liquid tank is positioned beside the pipe, the liquid level in the liquid tank and the liquid in the pipe are not changed. The liquid level is the same level when the pressure loss of the communication pipe is negligibly small. In this state, when the liquid level in the liquid tank is adjusted and the liquid level in the pipe is set to a predetermined height, even if the thickness measuring jig with the probe attached is inserted and pulled out of the pipe. Since the liquid in the liquid tank communicates with the liquid in the pipe, it is possible to prevent the liquid level in the pipe from sharply increasing.

Further, the liquid stopping device according to the present invention is mounted on a lower end of the pipe to close the lower end of the pipe, and to allow the liquid in the pipe to communicate with the liquid in the liquid tank through a communication pipe. A cylindrical body having a flange portion formed at the end on the pipe side and an external thread portion provided on the outer peripheral surface, and a female thread portion provided on the inner peripheral surface and screwing with the male screw portion of the cylindrical body to form an outer peripheral surface of the cylindrical body. A sleeve to be inserted, and the sleeve and the cylinder arranged side by side along the circumferential direction of the cylinder in a groove formed between the back surface of the flange portion formed at the tip of the cylinder and the tip surface of the sleeve. A plurality of expanding pieces which are pushed outward in the radial direction of the cylindrical body as the width of the groove (ie, the axial length of the cylindrical body) is reduced by screwing with the body, and the plurality of expanding pieces; Is mounted on the outer peripheral surface of the unit and can be extended in the radial direction by binding multiple expanded pieces A flexible ring, and an elastic cover that covers at least an outer surface from the pipe-side tip surface of the flange portion to the plurality of expanded pieces bound by the elastic ring. It is characterized in that the elastic ring is extruded outward and pressed against the inner peripheral surface of the pipe via the elastic cover.

[0011] With this configuration, the water stop device according to the present invention can be easily attached to the pipe, and is firmly fixed to the lower end of the pipe to prevent it from falling off the pipe. Also, liquid leakage from the pipe
The elastic ring can be prevented from being pressed against the inner peripheral surface of the pipe and the elastic cover.

In particular, since the pressure contact with the inner peripheral surface of the pipe is performed by pushing a plurality of expanding pieces outward, even if the inner diameter of the pipe fluctuates, it can be easily coped with and firmly fixed to the pipe. can do. Further, when a catalyst stopper called a ferrule having an inner diameter smaller than the inner diameter of the catalyst filling tube is installed at the lower end portion of the catalyst filling tube, the water stopping device according to the present invention provides an inner diameter of a portion for performing liquid stopping. There is an advantage that the liquid can be stopped at a predetermined portion by passing through a smaller portion. Therefore, the liquid stopping device according to the present invention is suitably used for the above-described ultrasonic inspection method for pipes.

In the present invention, the back surface of the flange portion formed at the distal end of the cylindrical body and the distal end surface of the sleeve are formed in a slanted shape such that the gap therebetween gradually increases outward in the radial direction. It is preferable that both end surfaces of each of the expanding pieces are formed in an inclined shape corresponding to the rear surface of the flange portion and the distal end surface of the sleeve, respectively. Thus, the radial movement (extrusion and return) of each expanding piece can be performed smoothly.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing an ultrasonic inspection method according to this embodiment. In FIG. 1, 1
Is a pipe to be inspected, and a plurality of pipes 1 are held by a tube sheet 2. The lower end of one of the pipes 1 is closed by a liquid stopper 3, and one end of a communication pipe 4 is connected to the liquid stopper 3. This communication pipe 4
Is connected to the bottom of the liquid tank 5.

Since the communication tube 4 is a tube made of a flexible material such as plastic or rubber, the height of the liquid tank 5 can be arbitrarily adjusted. The liquid tank 5 is a container having an open top. The liquid 6 is put in the liquid tank 5 and the pipe 1 connected by the communication pipe 4. This liquid 6 is for performing the thickness inspection of the pipe 1 by the above-mentioned ultrasonic water immersion method,
Usually, water is used, but a lower alcohol such as methyl alcohol or other various liquids may be used instead of water.

The liquid in the liquid tank 5 and the liquid in the pipe 1 communicate with each other through the communication pipe 4. For this reason, when the liquid tank 5 is located beside the pipe 1, the liquid surface 8 in the liquid tank 5 and the pipe 1
The liquid surface 9 is located in the same horizontal plane. Therefore, if the liquid level in the liquid tank 5 is set so that the liquid level 9 in the pipe 1 is at a predetermined height, further liquid is injected into the pipe 1 or the ultrasonic probe 7 To the liquid 6 in the pipe 1
Even when the liquid level rises due to immersion in the pipe, the liquid level rise in the pipe 1 is small, so that the liquid level overflows from the upper end of the pipe 1 due to the rapid liquid level rise and flows into another adjacent pipe. Can be suppressed.

The horizontal cross-sectional area of the liquid tank 5 is preferably as large as possible in order to prevent a sudden rise in the liquid level in the pipe 1. To suppress the liquid level fluctuation in the pipe 1 within 1 mm,
The horizontal sectional area of the liquid tank 5 is preferably at least m times the horizontal sectional area of the thickness measuring jig inserted into the pipe 1 (however,
m is the length of insertion of the thickness measuring jig into the pipe 1 (m
m)). In this case, if the liquid tank 5 having an excessively large horizontal cross-sectional area is used, handling becomes difficult. Therefore, when the allowable liquid level fluctuation in the pipe is n (mm), the horizontal cross-sectional area of the thickness measuring jig is determined. It is appropriate to use a liquid tank 5 having a horizontal sectional area of about m / n times.

After the liquid level in the pipe 1 is set at a predetermined position, the probe 7 is immersed in the liquid in the pipe 1 as described above, and an ultrasonic inspection is performed. That is, the probe 7 is inserted into the pipe 1 into which the liquid 6 has been injected, and ultrasonic waves are made to be incident perpendicularly on the inner surface of the pipe 1 directly or via a reflector such as an acoustic mirror (not shown). A method of measuring the difference between the propagation distance of the echo S from the normal inner surface of the pipe 1 without wall thinning and the echo S 'from the wall-thinned portion as the wall-thinning amount, and the propagation of ultrasonic waves through the pipe wall thickness The method of measuring time and converting it to thickness is used. By using this inspection method, it is possible to inspect each of the inner surface and the outer surface of the pipe 1 for the presence of a thinned portion.

As the water stop device 3 shown in FIG. 1, for example, a device in which a tube member such as a glass tube or a metal tube is inserted through a stopper member such as a rubber stopper or a cork stopper can be used. Is simply inserted into the lower end of the pipe 1, so that there is a danger that it will fall out of the pipe 1 by mistake. Therefore, it is necessary to use a water stopping device which can surely prevent the pipe 1 from coming off and has a high water stopping effect.

FIGS. 2 and 3 show a water stop device 3 according to a preferred embodiment of the present invention. Fig. 2 (a) and
2B is a partially cutaway side view showing the water stop device 3 in a normal state, and a cross-sectional view taken along line AA ′.

As shown in FIG. 2 (a), the liquid stopper 3
Is a cylinder 10 inserted into the lower end of the pipe,
0 on the outer peripheral surface. The cylindrical body 10 has a flange portion 12 formed at the tip, and a male screw portion 13 provided on the outer peripheral surface of the body portion. On the other hand, on the inner peripheral surface of the sleeve 11, there is provided a female screw portion 14 which is screwed with the male screw portion 13 of the cylindrical body 10.

A distal end cylindrical portion 18 coaxial with the cylindrical body 10 is integrally attached to the distal end of the cylindrical body 10 by welding or the like, and protrudes from the sleeve 11. Similarly, a rear end cylindrical portion 19 coaxial with the cylindrical body 10 is integrally attached to the rear end of the cylindrical body 10. The communication pipe 4 is fitted to the rear end tubular portion 19.
Further, a sleeve 11 is provided on the outer peripheral surface of the rear end portion of the cylindrical body 10.
A knob 20 for rotating the cylindrical body 10 to screw the male screw portion 13 and the female screw portion 14 is externally fixed. That is, the knob 20 is provided with a threaded screw hole 21 for screwing a set screw (not shown) for fixing the knob 20 on the outer peripheral surface of the cylindrical body 10.

A large-diameter portion 22 is provided at the rear end of the sleeve 11.
Is provided. The large diameter portion 22 is located outside the lower end of the pipe 1 when the water stop device 3 is used, and is for fixing the sleeve 11 with one hand when turning the knob 20 with the other hand. . The rear surface of the flange portion 12 and the distal end surface of the sleeve 11 are formed in a slanted shape such that the gap therebetween gradually increases outward in the radial direction, so that a trapezoidal groove 15 is provided between them. Is formed.

In the groove 15, a plurality of expanding pieces 16 are arranged along the circumferential direction of the cylindrical body 10. Both end surfaces of each expanding piece 16 are formed in a slope shape corresponding to the back surface of the flange portion 12 and the front end surface of the sleeve 11, respectively.
In the normal state shown in (1), the surfaces are in contact with each other. The plurality of expanding pieces 16 are bound by an elastic ring 17 mounted in a recess formed on the outer peripheral surface. As the elastic ring 17, for example, a normal O-ring made of a rubber material or the like which can be extended in the radial direction can be used.

In the liquid stopping device 3 shown in FIG. 2 configured as described above, when the knob 20 is turned to retract the cylinder 10 with respect to the sleeve 11 (in the direction of arrow C), the groove 1
5 (that is, the length in the axial direction of the cylindrical body) sequentially decreases.
Along with this, each expanding piece 16 is pushed outward in the radial direction of the cylindrical body 10, and as a result, the diameter D shown in FIG. 2B formed by arranging a plurality of expanding pieces 16 is greatly expanded. Become.

FIGS. 3 (a) and 3 (b) correspond to FIGS.
The enlarged state in which the plurality of expanding pieces 16 are completely extruded from the normal state shown in (b) is shown. That is, the sleeve 11
When the cylinder 10 is completely retracted with respect to
The base surface of the inclined surface is in contact with or close to the front end surface of the flange portion 12 and the back surface of the flange portion 12, so that the groove 15 has a cross-sectional shape substantially close to a triangle. At this time, each end of the expanding piece 16 slides on the end face of the sleeve 11 and the back face of the flange portion 12 and is pushed outward in the radial direction of the cylindrical body 10.
As shown in (b), the diameter D is greatly expanded.

Next, a method of closing the lower end of the pipe 1 using the liquid stopping device 3 according to the present invention will be described with reference to FIG. FIG. 4 shows the use state of the liquid stopping device 3.
As shown in FIG. 4, the part of the liquid stopping device 3 inserted into the pipe 1 except for the distal end cylindrical portion 18 has the elastic cover 2.
3 coated. This is because, as shown in FIG. 3 (b), in the expanded state in which the plurality of expanding pieces 16 are pushed outward, a gap is formed between the expanding pieces 16 and there is a risk of liquid leakage therefrom. This is because the elastic cover 23 prevents liquid leakage.

Therefore, the elastic cover 23 may cover at least the outer surface from the pipe-side end surface of the flange portion 12 to the plurality of expanding pieces 16 bound by the elastic ring 17. In this embodiment, the elastic cover 23
Has a length whose lower end reaches near the large-diameter portion 22, and the lower end is fixed by an elastic ring 24 such as an O-ring.
The elastic cover 23 has elasticity and is made of a rubber material such as natural rubber or synthetic rubber.

In order to close the lower end of the pipe 1 using the liquid stopping device 3, first, an elastic cover 23 is attached to the liquid stopping device 3 in a normal state shown in FIG. insert. Next, the large diameter portion 22 at the rear end of the sleeve 11 is gripped and fixed with one hand, and the knob 20 is turned with the other hand to screw the cylinder 10 backward (in the direction of arrow C). Along with this, the width of the groove 15 is reduced, and the plurality of expanded pieces 16
Is gradually pushed outward to increase the diameter D. Then, the elastic cover 23 is brought into contact with the inner surface of the pipe 1, and the knob 20 is further turned to push out the plurality of expanding pieces 16 outward, and the elastic ring 17 is strongly pressed against the inner surface of the pipe 1 via the elastic cover 23. .

Thus, as shown in FIG. 4, the liquid stopping device 3 is firmly fixed to the lower end of the pipe 1 and does not easily fall off due to liquid pressure or the like, and exhibits a high liquid stopping effect to prevent liquid leakage. To prevent. Therefore, as shown in FIG. 1, it is suitable for use in ultrasonic inspection of a pipe, which is performed by injecting a liquid into a pipe 1 which is connected to a liquid tank 5 via a communication pipe 4.

When the present invention is applied to a pipe having a diameter larger than that of the pipe 1 shown in FIG. 4, the expanded piece 16 is replaced with a pipe having a larger thickness, and the extruded length is made larger. It can be easily handled.

[0032]

According to the ultrasonic inspection method of the present invention, the liquid in the pipe is communicated with the liquid in the liquid tank through the communication pipe,
The liquid level in the pipe is set to a predetermined level by adjusting the liquid level in the liquid tank.Therefore, even if the thickness measurement jig is inserted into or pulled out of the pipe, the Since it is possible to prevent the surface height from rising sharply and the liquid from overflowing from the pipe, there is an effect that the ultrasonic inspection work becomes easy.

Further, in the liquid stopping device according to the present invention, the plurality of expanding pieces are respectively pushed outward in the radial direction of the cylindrical body to press the elastic ring against the inner peripheral surface of the pipe. There is an effect that, while being fixed, the lower end of the pipe is closed, and the lower end of the pipe is surely closed to prevent liquid leakage.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing an ultrasonic inspection method for a pipe according to an embodiment of the present invention.

FIGS. 2 (a) and (b) are partially cutaway side views showing a main part of a water stop device in a normal state, and AA 'thereof.
It is a line sectional view.

FIGS. 3 (a) and 3 (b) are partially cutaway side views showing a main part of the water stop device in an enlarged state, and BB 'thereof.
It is a line sectional view.

FIG. 4 is a partially broken explanatory view showing a use state of the water stop device.

FIG. 5 is an explanatory view showing a conventional ultrasonic inspection method for pipes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 2 Tube plate 3 Liquid stopping device 4 Communication pipe 5 Liquid tank 6 Liquid 7 Probe 8 Liquid surface 9 Liquid surface 10 Cylindrical body 11 Sleeve 12 Flange part 13 Male thread part 14 Female thread part 15 Groove 16 Expansion piece 17 Elastic ring 23 Elastic cover

Claims (3)

[Claims] 1. An ultrasonic inspection method for inspecting a pipe by inserting an ultrasonic probe into a pipe into which a liquid has been injected, wherein the liquid in the pipe is supplied through a communication pipe extending from a lower end of the pipe. An ultrasonic inspection method for a pipe, comprising communicating with a liquid in a tank, adjusting a liquid level in the liquid tank, and setting a liquid level in the pipe to a predetermined height. 2. A liquid stopping device mounted on a lower end of a pipe for closing a lower end of the pipe and communicating a liquid in the pipe with a liquid in a liquid tank through a communication pipe. A cylindrical body having a male thread portion provided on an outer peripheral surface thereof, a female screw portion provided on an inner peripheral surface, and a sleeve screwed with a male screw portion of the cylindrical body and externally inserted into the outer peripheral surface of the cylindrical body; The sleeve is arranged along the circumferential direction of the cylindrical body in a groove formed between the back surface of the flange portion formed at the distal end of the cylindrical body and the distal end surface of the sleeve. As a result, a plurality of expanded pieces that are extruded outward in the radial direction of the cylindrical body as the width of the groove becomes smaller, and a plurality of expanded pieces mounted on the outer peripheral surface of the plurality of expanded pieces are bound. An elastic ring that can extend in the radial direction of the cylindrical body; An elastic cover covering an outer surface from the tip end surface to the plurality of expansion pieces bound by the elastic ring, and extruding the plurality of expansion pieces radially outward to release the elastic ring. A liquid stopping device, which is brought into pressure contact with an inner peripheral surface of a pipe via an elastic cover. 3. A back surface of a flange portion formed at a distal end of the cylindrical body and a distal end surface of the sleeve are formed in an inclined shape such that a gap therebetween gradually increases radially outward of the cylindrical body. 3. The liquid stopping device according to claim 2, wherein each of the expanding pieces has both end faces formed in a slanted shape corresponding to the rear face of the flange portion and the tip end face of the sleeve, respectively.