JP2001208732A - Ultrasonic measuring method from inner surface side of tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an ultrasonic-wave transmitting medium liquid from directly wetting the inner surfaces of a tube and to reduce the amount of use of the ultrasonic- wave transmitting medium liquid when ultrasonic measurement is a performed from the inner surface side of the tube. SOLUTION: When wall thickness measurement and flaw detection are performed on a tube 3 from the inner surface side of the tube 3 through the use of an ultrasonic sensor 1, the gap between the ultrasonic sensor 1 and tube 3 is filled with the ultrasonic transmitting medium liquid 8. The ultrasonic transmitting medium liquid 8 is sealed in a balloon-shaped bag 2. The ultrasonic sensor 1 is housed together with pigs for centering 4 and 5 in the balloon-shaped bag 2 and supported at the center location of the axis of the tube 3 by the pigs for centering 4 and 5. As it is satisfactory that only the periphery of the ultrasonic sensor 1 is filled with the ultrasonic transmitting medium liquid 8, it is possible to reduce the capacity of the balloon-shaped bag 2 and to shorten the work and time required for ultrasonic measurement. Even if the balloon-shaped bag 2 is broken, as the amount of leakage of the ultrasonic transmitting medium liquid 8 is small, it is possible to reduce the extent of damage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring ultrasonic waves from the inner surface side of a pipe for city gas conduits and the like from the inner surface side.

[0002]

2. Description of the Related Art Conventionally, tube thickness measurement and flaw detection using ultrasonic waves have been performed. Since the ultrasonic measurement can be performed nondestructively, it is possible to measure an initial failure, thinning during use, and the like. In ultrasonic measurement from the inner surface side, an ultrasonic signal is transmitted from a sensor having a function of transmitting and receiving ultrasonic waves and propagated from the inner peripheral surface of the tube to the outer peripheral surface of the tube, and the outer peripheral surface and the inner surface of the tube are measured. The signal reflected by the peripheral surface and the defect is received by an ultrasonic sensor in the tube, and the thickness measurement and the flaw detection are performed based on the difference in the propagation time of the ultrasonic wave. Ultrasonic measurement can be performed from the outer peripheral side of the pipe.However, city gas pipes are often buried underground, and if you want to understand the thinning situation due to corrosion of the underground pipe, In order to measure the wall thickness from the outer surface of the pipe, excavation of soil or the like is required. For this reason, it is desired to insert an ultrasonic sensor into the tube and perform ultrasonic measurement from the inner surface side of the tube.

[0003] Generally, when performing ultrasonic measurement, in order to transmit ultrasonic waves without loss between the ultrasonic sensor and the object to be measured, water or water is interposed between the probe of the ultrasonic sensor and the surface of the object. An ultrasonic propagation medium liquid (couplant) such as oil is used. When an ultrasonic sensor is inserted into a tube to be measured and ultrasonic measurement is performed from the inner surface of the tube, a water immersion method that fills the inside of the tube with an ultrasonic propagation medium liquid is often used.

However, in a city gas conduit, a water immersion method in which the inner surface of the tube is wetted with water as an ultrasonic wave propagation medium liquid,
It must be avoided because it could lead to a city gas supply failure accident. When performing ultrasonic measurement using an ultrasonic sensor, it is possible to fill the space between the ultrasonic sensor and the inner surface of the tube with the ultrasonic wave propagation medium liquid without directly wetting the inside of the tube with the ultrasonic wave propagation medium liquid. As a prior art, there is one disclosed in Japanese Patent Publication No. 4-38282. In this prior art, a tube is attached to a gas tube to form a closed space, and the tube is filled with an ultrasonic wave propagation medium liquid such as water to perform ultrasonic measurement. After the measurement is completed, if the ultrasonic propagation medium liquid in the tube is sucked out and the tube is removed from the tube, the ultrasonic measurement can be performed without wetting the inner surface side of the tube with the ultrasonic transmission medium solution. Can be.

[0005]

[Problems to be Solved by the Invention]
By using the prior art disclosed in the above publication, it is possible to perform ultrasonic measurement using a water immersion method from the inner surface side of a pipe, such as a city gas pipe, whose inner surface is not desired to be wet with water.
However, as in this prior art, in a method in which a tube is attached to a tube and filled with an ultrasonic propagation medium liquid such as water, and an ultrasonic sensor is moved in the axial direction of the tube inside the tube, ultrasonic waves are transmitted from an opening of the tube. It is necessary to fill the inside of the tube up to the portion where the measurement is performed with the ultrasonic wave propagation medium liquid, and the amount of the ultrasonic wave propagation medium liquid used becomes extremely large. For this reason,
If the tube breaks, a large amount of the ultrasonic wave propagation medium liquid may wet the inner surface of the tube widely. In addition, the time required for enclosing and extracting the ultrasonic wave propagation medium liquid becomes longer, so that the work time required for measurement also becomes longer.

SUMMARY OF THE INVENTION It is an object of the present invention to measure an ultrasonic wave without wetting the inside of a tube with an ultrasonic wave propagating medium liquid, and to reduce an amount of the ultrasonic wave propagating medium liquid from an ultrasonic wave from the tube inner surface side. It is to provide a measuring method.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for transmitting ultrasonic waves from the inner surface of a tube and receiving reflected waves to perform ultrasonic measurement, comprising: an ultrasonic sensor for performing ultrasonic measurement; A balloon-shaped bag having elasticity and elasticity is interposed between the inner surface of the tube and the balloon-shaped bag is inserted into the tube from the opening of the tube together with the ultrasonic sensor in a state where the balloon-shaped bag is not inflated. The ultrasonic wave propagating medium liquid is sealed and inflated in the inserted balloon-shaped bag, and the inner surface side of the bag and the ultrasonic sensor are connected with the outer surface of the bag being in close contact with the inner surface of the tube. A method for measuring ultrasonic waves from the inner side of a tube, characterized in that the ultrasonic wave propagating medium liquid is filled in between the tubes and ultrasonic measurement is performed.

According to the present invention, there is elasticity and elasticity between an ultrasonic sensor for transmitting ultrasonic waves from the inner surface of the tube and receiving reflected waves to perform ultrasonic measurement and the inner surface of the tube. A balloon-shaped bag is interposed. The balloon-like bag is inserted into the pipe through the opening of the pipe together with the ultrasonic sensor without being inflated. Since the balloon-shaped bag is not inflated, the bag and the ultrasonic sensor can be freely and easily inserted into the tube. When the ultrasonic wave propagation medium liquid is sealed in the balloon-shaped bag inserted into the tube and inflated, and the outer peripheral surface of the bag is in close contact with the inner peripheral surface of the tube, the space between the inner surface side of the tube and the ultrasonic sensor is removed. Is filled with the ultrasonic propagation medium liquid, and the ultrasonic wave transmitted from the ultrasonic sensor passes through the bag membrane through the ultrasonic propagation medium liquid,
Ultrasound transmitted to the inner surface side of the pipe with little loss, and ultrasonic waves reflected from defects in the wall thickness of the pipe and the outer peripheral surface of the pipe return to the ultrasonic sensor via the ultrasonic propagation medium liquid, similar to the water immersion method Ultrasonic measurement can be performed. Since the balloon-shaped bag may be provided so as to cover the periphery of the ultrasonic sensor, it is possible to reduce the amount of the ultrasonic wave propagating medium liquid to be used and to shorten the work and time required for ultrasonic measurement.

Further, the present invention is characterized in that the wall thickness of the tube is measured as the ultrasonic measurement.

According to the present invention, the wall thickness of the tube can be measured by interposing the ultrasonic wave propagation medium liquid between the inner surface side of the bag and the ultrasonic sensor.

Further, the present invention is characterized in that the flaw detection of the tube is performed as the ultrasonic measurement.

According to the present invention, it is possible to detect a flaw in a tube by interposing an ultrasonic wave propagation medium liquid between the inner surface side of the bag and the ultrasonic sensor.

[0013]

FIG. 1 shows an outline of an ultrasonic measuring method according to an embodiment of the present invention. FIG. 1A shows a state in which an ultrasonic sensor 1 and a balloon-shaped bag 2 are inserted into a tube 3. FIG. 1B shows a state in which the balloon-shaped bag 2 is inflated to perform ultrasonic measurement.

The ultrasonic sensor 1 is arranged so that a radial distance from a surface located at the center of the tube 3 for transmitting and receiving ultrasonic waves to an inner surface of the tube 3 is uniform. Are provided with centering pigs 4 and 5 before and after. Part or all of the outer peripheral surfaces of the centering pigs 4 and 5 are almost in contact with the inner surface of the tube 3, and the center of the ultrasonic sensor 1 is adjusted so that the axis of the ultrasonic sensor 1 matches the axis of the tube 3. Supporting position. The balloon-shaped bag 2 is made of a material having elasticity and elasticity, such as rubber or synthetic resin, and includes the ultrasonic sensor 1 and the centering pigs 4,5.
It covers the whole. The centering pigs 4, 5
A part or the whole of the outer periphery has a cushioning property such as a spring structure, and has a structure capable of passing a bent portion or a step of a pipe.

A balloon-shaped bag 2 containing an ultrasonic sensor 1 and centering pigs 4 and 5 as shown in FIG. 1 is inserted into the tube 3 through an opening provided on one side of the tube 3 in the axial direction. . The sensor cable 6 and the liquid filling tube 7 are drawn out from the balloon-shaped bag 2 toward the opening of the tube 3.

As shown in FIG. 1A, when the ultrasonic wave propagation medium liquid 8 is hardly sealed in the balloon-shaped bag 2,
The ultrasonic sensor 1 and the centering pigs 4, 5 contained in the balloon-shaped bag 2 can be easily moved in the axial direction of the tube 3. In particular, if the sensor cable 6 and the liquid filling tube 7 have a certain degree of rigidity, the ultrasonic sensor 1 and the centering pig 4 together with the balloon-shaped bag 2 can be used not only in the pulling direction but also in the pushing direction. 5 can be moved within the tube 3.

As shown in FIG. 1 (b), when the ultrasonic wave propagation medium liquid 8 is sealed in the balloon-like bag 2 via the liquid filling tube 7 and the balloon-like bag 2 is inflated, the ultrasonic wave An ultrasonic wave propagation medium liquid 8 can be filled between the sensor 1 and the inner surface of the bag 2. In this state, ultrasonic measurement equivalent to the water immersion method can be performed. If the ultrasonic sensor 1 is moved back and forth by pushing and pulling the cable 6 with the bag 2 and the tube 7 fixed, ultrasonic measurement can be performed in a fixed section in the axial direction of the tube 3. Also, the balloon-shaped bag 2 does not cover the entire inner surface of the tube 3 but only covers a limited portion around the ultrasonic sensor 1, so that it is necessary to inflate the balloon-shaped bag 2. The amount of the ultrasonic propagation medium liquid 8 can be reduced. Therefore, even if the balloon-shaped bag 2 is torn and the ultrasonic wave propagation medium liquid 8 leaks into the pipe 3, damage can be minimized.

FIG. 2 shows an example of a signal waveform corresponding to an ultrasonic wave propagation state in a portion where an ultrasonic test is performed in the embodiment of FIG. That is, as shown in FIG. 2A, the transmitted ultrasonic wave 10 transmitted from the ultrasonic sensor 1 passes through the ultrasonic wave propagating medium liquid 8, passes through the coating surface of the balloon-shaped bag 2, and flows through the inside of the tube 3. After reaching the peripheral surface 3a side, a part thereof is reflected and returns from the ultrasonic wave propagating medium liquid 8 to the ultrasonic sensor 1 through the film of the balloon-like bag 2. A part of the transmitted ultrasonic wave 10 further proceeds from the thick inner peripheral surface 3a of the tube 3 to the outer peripheral surface 3b, is reflected and the reflected ultrasonic waves 11 propagate from the outer peripheral surface 3b of the tube 3 to the inner peripheral surface 3a. Then, the liquid returns from the ultrasonic wave propagation medium liquid 8 to the ultrasonic sensor 1 through the film of the balloon-shaped bag 2. As shown in FIG. 2 (b), if the ultrasonic sensor 1 transmits the ultrasonic wave in a pulsed form and monitors the signal output of the reflected ultrasonic wave 11 received, the reflection on the inner peripheral surface 3a of the tube 3 is obtained. The wall thickness of the tube 3 can be measured from the time difference between the reflection on the outer peripheral surface 3b and the propagation speed of the ultrasonic wave. As shown in FIG. 2C, when a defect 12 exists in the tube 3, a reflected ultrasonic wave 11 is generated with respect to a transmitted ultrasonic wave 10 incident on the defect 12. With the signal output as shown in FIG. 2D, the reception timing of the reflected ultrasonic wave 11 from the defect 12 depends on the reception timing from the inner peripheral surface 3a side and the reception timing from the outer peripheral surface 3b side as shown in FIG. Of the reception timing.

FIG. 3 shows a sectional structure of the ultrasonic sensor shown in FIG. 1 as viewed from the axial direction of the tube 3. The ultrasonic sensor 1 has a plurality of probes 1 spaced at intervals in the circumferential direction.
3 are arranged. In the present embodiment, as shown in FIG.
Since the position of the ultrasonic sensor 1 is held by the centering pigs 4 and 5 so as not to deviate from the axis of the tube 3, it is necessary to perform ultrasonic measurement at different positions around the axis with a plurality of, for example, 12 probes 13. Can be.

When the ultrasonic wave propagation medium liquid 8 is hardly sealed in the balloon-shaped bag 2 as shown in FIG. 1A, a lubricant or the like is applied to the surface of the balloon-shaped bag 2. In this case, it is possible to smoothly pass the pipe 3 even at a bent portion. A balloon-shaped bag 2 as shown in FIG.
If the inner peripheral surface 3a side of the tube 3 is smooth even when the ultrasonic wave propagation medium liquid 8 is sealed by inflating the ultrasonic sensor 1, the ultrasonic sensor 1 together with the balloon-shaped bag 2 is moved in the axial direction of the tube 3. Can be. In the present embodiment, the space between the inner surface of the tube 3 and the ultrasonic sensor 1 is filled with the ultrasonic wave propagating medium liquid 8 without the ultrasonic wave propagating medium liquid 8 directly wetting the inner surface of the tube 3 using the balloon 2. Ultrasonic measurement by a water immersion method can be performed. As the ultrasonic wave propagation medium liquid 8, for example, water or oil can be used. Since the balloon-shaped bag 2 only needs to fill the ultrasonic propagation medium liquid 8 around the centering pigs 4 and 5 and the ultrasonic sensor 1, the volume is reduced and the volume of the ultrasonic transmission medium liquid 8 for enclosing is reduced. Can be reduced. The amount of the ultrasonic wave propagating medium liquid 8 sealed during measurement as shown in FIG. 1B is small, so that even if the balloon-shaped bag 2 is torn, the ultrasonic wave propagating medium leaking from the balloon-shaped bag 2 The amount of the liquid 8 is small, and damage in case of leakage can be minimized.

FIG. 4 shows a schematic configuration of another embodiment of the present invention. In the present embodiment, portions corresponding to the embodiment shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. The balloon-shaped bag 22 of the present embodiment is provided so as to cover the periphery of the ultrasonic sensor 1 in a ring shape. That is, the ultrasonic sensor 1 is not stored in the balloon-shaped bag 22, but the outer peripheral surface and the inner peripheral surface of the balloon-shaped bag 22 are stored between the ultrasonic sensor 1 and the inner surface of the tube 3. This balloon-shaped bag 2
2 is filled with the ultrasonic wave propagation medium liquid 8, so that ultrasonic measurement similar to the water immersion method can be performed. In the present embodiment, since the capacity of the balloon-shaped bag 22 can be further reduced, damage in the event of a breakage can be further reduced.

[0022]

As described above, according to the present invention, when the ultrasonic measurement is performed from the inner surface side of the tube, the ultrasonic propagation medium liquid is filled between the inner surface side of the tube and the ultrasonic sensor. A measurement can be made. Since the ultrasonic wave propagation medium liquid comes into contact with the inner surface side of the tube via the bag, the inner surface side of the tube does not directly wet with the ultrasonic wave propagation medium liquid, and furthermore, the amount of the ultrasonic wave propagation medium liquid is reduced, Quick measurement can be performed. Even for pipes that are difficult to measure from the outside of the pipe and do not want the inside of the pipe to be wet with water, such as pipes of city gas buried underground, ultrasonic measurement of the pipe by the water immersion method using an ultrasonic sensor can be performed. It can be carried out.

Further, according to the present invention, the measurement of the wall thickness of the pipe can be performed from the inner surface side of the pipe in a state similar to the water immersion method.

Further, according to the present invention, flaw detection of the pipe can be performed from the inner surface side of the pipe in a state similar to the water immersion method.

[Brief description of the drawings]

FIG. 1 is a simplified cross-sectional view schematically showing a state where ultrasonic flaw detection is performed according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing an ultrasonic wave propagation state when performing ultrasonic measurement in the embodiment of FIG. 1 and a graph showing reception timing of an ultrasonic detection signal.

FIG. 3 is a simplified sectional view showing an arrangement of a probe 13 in the ultrasonic sensor 1 of FIG.

FIG. 4 is a simplified cross-sectional view showing an outline of a method for performing ultrasonic measurement according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic sensor 2, 22 Balloon-shaped bag 3 Tube 4, 5 Centering pig 6 Sensor cable 7 Liquid filling tube 8 Ultrasonic propagation medium liquid 10 Transmitted ultrasonic wave 11 Reflected ultrasonic wave 12 Defect 13 Probe

Claims (3)

[Claims] 1. A method for transmitting an ultrasonic wave from an inner surface of a tube and receiving a reflected wave to perform an ultrasonic measurement, wherein an elastic force is provided between an ultrasonic sensor for performing the ultrasonic measurement and the inner surface of the tube. A balloon-shaped bag having elasticity and elasticity is interposed, and the balloon-shaped bag is inserted into the tube from the opening of the tube together with the ultrasonic sensor without being inflated, and the balloon-shaped bag inserted into the tube is inserted. The ultrasonic wave propagating medium liquid is filled between the bag and the ultrasonic sensor while the outer peripheral surface of the bag is in close contact with the inner peripheral surface of the tube. A method for measuring ultrasonic waves from the inner surface side of a pipe, characterized by satisfying (1) and performing ultrasonic measurement. 2. The method for measuring ultrasonic waves from the inner surface of a pipe according to claim 1, wherein the thickness of the pipe is measured as the ultrasonic measurement. 3. The method for measuring ultrasonic waves from the inner surface of a pipe according to claim 1, wherein the ultrasonic measurement is performed by flaw detection of the pipe.