Patent Description:
Various inspection methods are known which are used to detect flaws, such as wall-thinning and cracking, caused by corrosion of or damage to an inspection object member which is, for example, a hollow steel member, such as a pipe or a tank. To inspect an inspection object member over a wide range, for example, Patent Literatures <NUM> to <NUM> each disclose an inspection apparatus that uses magnetic wheels to run while being attracted to the surface of the inspection object member. The inspection apparatuses disclosed in Patent Literatures <NUM> and <NUM> adopt an ultrasonic inspection method, whereas the inspection apparatus disclosed in Patent Literature <NUM> adopts an inspection method using eddy current by a coil.

In further prior art, <CIT> discloses a device for detecting defects of an iron-based closed container.

Patent Literatures <NUM> to <NUM> disclose a configuration in which, as illustrated in <FIG>, an inspection apparatus <NUM> that runs while being attracted to the surface of an inspection object member T, such as a pipe, is connected by wired connection through a cable C to an inspection apparatus main body <NUM>, such as a signal processor, a control apparatus, or an eddy-current flaw detector. A flaw signal detected by the inspection apparatus <NUM> is transmitted through the cable C to the inspection apparatus main body <NUM>.

Although the inspection apparatus <NUM> disclosed in Patent Literatures <NUM> to <NUM> is capable of running over the surface of the inspection object member T, the inspection range of the inspection apparatus <NUM> is limited by the length of the cable C.

Patent Literature <NUM> discloses a configuration in which an eddy-current sensor unit that moves over the inspection object member is connected through a cable to an eddy-current flaw detector, which is mounted on a movable carriage. This allows the movable carriage to follow the movement of the eddy-current sensor unit, and makes it less likely that the inspection range of the eddy-current sensor unit will be limited. Even with this configuration, however, the movable carriage cannot run as the eddy-current sensor unit moves if there is no enough space for the movable carriage to run along the inspection object member, or if the conditions of the road surface on which the movable carriage runs along the inspection object member are not good enough. In such cases, the inspection range of the inspection apparatus is still limited by the length of the cable.

For the inspection apparatuses disclosed in Patent Literatures <NUM> to <NUM>, lengthening the cable C to extend the inspection range increases the weight of the cable C applied to the inspection apparatus <NUM>. As a result, the attracting force of the magnetic wheels for attracting the inspection apparatus <NUM> to the surface of the inspection object member T may become no longer able to support the weight of the cable C applied to the inspection apparatus <NUM>, and the inspection apparatus <NUM> may fall off the inspection object member T. To prevent such a problem, the cable C has a limited length, and it has therefore been difficult to extend the inspection range of the inspection apparatus <NUM>.

The inspection object member T, such as a pipe, is often installed high above the ground. To inspect each area of the inspection object member T, therefore, it has been required to build a scaffold S along the entire inspection object member T and carry out the inspection on the scaffold S, so as not to increase the weight of the cable C applied to the inspection apparatus <NUM>. As a result, installing the scaffold S to inspect the inspection object member T has involved a considerable number of staff hours.

To detect flaws in an inspection object member with an ultrasonic inspection apparatus as disclosed in Patent Literature <NUM> or <NUM>, immersion testing is generally adopted to reduce the influence of surface roughness of the inspection object member. Ultrasonic inspection using immersion testing involves using a large quantity of water, because an ultrasonic probe is locally immersed in water to avoid direct contact with the inspection object member. This has required the use of a hose for supplying water and a pump for supplying water to an area to be inspected. Without a pump, the inspection range has been significantly limited because water cannot be supplied to an area to be inspected if the area is high above the ground.

To solve the problems described above, the present invention aims to provide an inspection apparatus, an inspection system, and an inspection method that are capable of stably and efficiently inspecting an inspection object member for flaws over a wide range without limiting the range of inspection on the inspection object member. The present invention also aims to provide a member repair method.

Measures to solve the problems described above are as follows.

An inspection apparatus is provided which comprises an inspection apparatus main body having a moving mechanism movable along a surface of an inspection object member; a measuring device provided on the inspection apparatus main body and configured to measure a wall thickness of the inspection object member; a transmitter provided on the inspection apparatus main body and configured to wirelessly transmit information about the wall thickness measured by the measuring device to the outside; and a battery provided on the inspection apparatus main body and configured to supply power to the moving mechanism, the measuring device, and the transmitter, wherein the inspection object member is a magnetic body, and the measuring device includes a magnetizer configured to apply a static magnetic field to the inspection object member to produce eddy current therein, an eddy current sensor configured to measure the eddy current produced in the inspection object member, and a phase detector configured to detect a phase of a waveform of the eddy current measured by the eddy current sensor, wherein the magnetizer is a permanent magnet.

In an embodiment, the moving mechanism is a magnetic crawler configured to run along the surface of the inspection object member while being attracted by magnetic force to the surface thereof.

In an embodiment, an -inspection system is provided which comprises the inspection apparatus described above and a control apparatus configured to receive the information wirelessly transmitted from the inspection apparatus and detect a flaw in the inspection object member on the basis of the information.

An inspection method is provided which comprises receiving, at a position distant from the inspection apparatus described above, the information wirelessly transmitted from the inspection apparatus; and detecting a flaw in the inspection object member on the basis of the information.

In an embodiment of the inspection method described above, the inspection object member is a hollow steel member.

A member repair method is provided which includes detecting the flaw in the inspection object member by the inspection method described above, and repairing a part of the inspection object member where the flaw has been detected.

In an inspection apparatus, an inspection system, and an inspection method and a member repair method according to the present invention, the inspection apparatus moves along the surface of an inspection object member to measure the thickness of the inspection object member, and wirelessly transmits information about the measured thickness to the outside. This eliminates the need for connecting a cable for transmitting, to the outside, the information measured by the inspection apparatus. Therefore, without being limited in inspection range by the length or weight of the cable, the inspection apparatus can stably and efficiently inspect the inspection object member for flaws over a wide range.

When the inspection object member is a magnetic body, a measuring device includes a magnetizer, an eddy current sensor, and a phase detector, and a permanent magnet is used as the magnetizer. The magnetizer applies a static magnetic field to the inspection object member to produce eddy current therein, the eddy current sensor measures the eddy current produced in the inspection object member, and the phase detector detects the phase of a waveform of the measured eddy current. This eliminates the need for supplying power to the magnetizer, and reduces power consumed to produce eddy current. Thus, power to be consumed by the inspection apparatus can be sufficiently supplied by a battery provided on the inspection apparatus main body.

When the moving mechanism is a magnetic crawler that runs along the surface of the inspection object member while being attracted by magnetic force to the surface of the inspection object member, the magnetic crawler is firmly in contact with the surface of the inspection object member even when the surface is curved. This increases the contact area and provides stable attracting force.

With reference to the drawings, an embodiment of an inspection apparatus, an inspection system, and an inspection method and a member repair method according to the present invention will be described in detail.

As illustrated in <FIG>, an inspection apparatus <NUM>, an inspection system <NUM>, and an inspection method according to the present embodiment are used to detect a flaw T0 (see <FIG>) in a pipe (inspection object member, hollow steel member) T constituted by a steel pipe, which is a magnetic body. The flaw T0 in the pipe T is, for example, wall-thinning or cracking caused by corrosion of, or damage to, the pipe T. A member repair method according to the present embodiment is used to correct the detected flaw T0.

<FIG> schematically illustrates a cross-section of the inspection apparatus <NUM> according to the present embodiment. A housing <NUM> in the inspection apparatus <NUM> is provided with moving mechanisms <NUM> on the side faces thereof. The moving mechanisms <NUM> are movable along the surface of the pipe T. The housing <NUM> and the moving mechanisms <NUM> constitute an inspection apparatus main body. The housing <NUM> in the inspection apparatus <NUM> has measuring devices <NUM> to <NUM>, a wireless transceiver (transmitter) <NUM>, and a battery <NUM> included therein or mounted thereon. The battery <NUM> supplies power to the moving mechanisms <NUM>, the measuring devices <NUM> to <NUM>, and the wireless transceiver <NUM>.

A general configuration of the inspection system <NUM> according to the present embodiment is illustrated in <FIG>. The inspection system <NUM> includes the inspection apparatus <NUM> and a control apparatus <NUM>. The control apparatus <NUM> receives information about the wall thickness of the pipe T wirelessly transmitted from the inspection apparatus <NUM>, and detects the flaw T0 in the pipe T on the basis of this information.

As illustrated in <FIG>, the moving mechanisms <NUM> of the inspection apparatus <NUM> are composed of magnetic crawlers capable to be attracted by magnetic force to the surface of the pipe T. The moving mechanisms <NUM> are disposed on both sides of the housing <NUM> in the inspection apparatus <NUM>. A crawler, which is also called an endless track here, is a moving mechanism in which an annular belt formed of an elastic member or a series of shoes annularly connected by links is attached to and extended around a set of driving wheels, idle wheels and others. The crawler is thus capable of running on a surface having an irregular shape.

In the present embodiment, the moving mechanisms <NUM> each are a magnetic crawler having a structure in which magnets are embedded in an annular belt made of an elastic material, such as rubber. As the magnetic crawler moves, the inspection apparatus <NUM> moves on the surface of the pipe T while being attracted by magnetic force of the magnetic crawler to the surface of the pipe T.

As illustrated in <FIG>, the moving mechanism <NUM> includes a motor <NUM> that moves driving wheels, and a movement controller 12C that controls the motion of the motor <NUM>.

As illustrated in <FIG>, the pipe T is formed by joining a plurality of steel pipes. The pipe T has weld beads T1 and flanges T2 at joints of adjacent ones of the steel pipes. The pipe T is supported by a support T3 and secured to the ground.

The flanges T2 of the pipe T protrude from the surface of the pipe T much more than the weld beads T1. This often makes it difficult to move the inspection apparatus <NUM> over the flanges T2. To inspect the pipe T with the inspection apparatus <NUM>, the inspection system <NUM>, and the inspection method according to the present embodiment, therefore, an inspector places the inspection apparatus <NUM> in each section of the pipe T defined by the flanges T2.

If a section of the pipe T defined by the flanges T2 is high above the ground, a scaffold S is built near this section to place the inspection apparatus <NUM> on the surface of the pipe T. By wirelessly manipulating the inspection apparatus <NUM> from the control apparatus <NUM> on the ground, for example, the inspection apparatus <NUM> is moved along the surface of the pipe T within the section defined by the flanges T2, to an area away from the scaffold S.

As a method for measuring the wall thickness of the pipe T, which is an inspection object member, the inspection apparatus <NUM> according to the present embodiment adopts an eddy current method. Specifically, as illustrated in <FIG>, the measuring devices <NUM> to <NUM> include a magnetizer <NUM> composed of a permanent magnet, an eddy current sensor <NUM>, and a phase detector <NUM>. The magnetizer <NUM> applies a static magnetic field to the pipe T, which is a magnetic body, to produce eddy current therein. Although the magnetizer <NUM> (permanent magnet) illustrated in <FIG> is constituted by a pair of members spaced apart from each other, the shape of the magnetizer <NUM> is not limited to that illustrated in <FIG>. For example, the magnetizer <NUM> may be constituted by a single inverse U-shaped member. The eddy current produced in the pipe T is measured by the eddy current sensor <NUM>. The waveform of the eddy current measured by the eddy current sensor <NUM> is transmitted to the phase detector <NUM>, which detects the phase of the eddy current to measure the wall thickness of the pipe T. When measuring the wall thickness of the pipe T, the inspection apparatus <NUM> is simply required to measure at least surface irregularities (or variations in thickness) of the pipe T, and is not necessarily required to measure the absolute value (or numeric value) of the thickness of the pipe T.

Information about the wall thickness of the pipe T measured by the measuring devices <NUM> to <NUM> is wirelessly transmitted from the wireless transceiver <NUM> to a wireless transceiver <NUM> of the control apparatus <NUM> described below.

The control apparatus <NUM> is composed of a general-purpose personal computer (PC). Specifically, as illustrated in <FIG>, the control apparatus <NUM> includes the wireless transceiver <NUM> and a central processing unit (CPU) <NUM>. The wireless transceiver <NUM> receives information about the wall thickness of the pipe T wirelessly transmitted from the wireless transceiver <NUM> of the inspection apparatus <NUM>. The CPU <NUM> processes the information received by the wireless transceiver <NUM>.

The CPU <NUM> wirelessly transmits a signal from the wireless transceiver <NUM> of the control apparatus <NUM> to the wireless transceiver <NUM> of the inspection apparatus <NUM> automatically or in response to, for example, an inspector's operation. The CPU <NUM> thus controls the inspection apparatus <NUM> in such a way that it runs over the entire region of the surface of the pipe T, measures the wall thickness over the entire surface of the pipe T, and wirelessly transmits information about the measured wall thickness to the control apparatus <NUM>. The CPU <NUM> then detects the flaw T0 in the pipe T on the basis of the information about the wall thickness of the pipe T transmitted from the inspection apparatus <NUM>. Specifically, if the amount of change in wall thickness is greater than or equal to a predetermined value, the CPU <NUM> determines that there is the flaw T0 in the pipe T. The CPU <NUM> then notifies the inspector of detection of the flaw T0 in the pipe T, for example, through display on the screen. Software for executing the series of processing described above is installed on the PC composing the control apparatus <NUM>. As the control apparatus <NUM>, another information processing device, such as a tablet terminal, may be used instead of the PC. As described above, the control apparatus <NUM> installed at a distance from the inspection apparatus <NUM> receives information about the wall thickness wirelessly transmitted from the inspection apparatus <NUM>, and detects the flaw T0 in the pipe T. The inspection method according to the present embodiment is thus implemented.

The flaw T0 in the pipe T is detected by the inspection method described above, and a part of the pipe T where the flaw T0 has been detected is repaired. The member repair method according to the present embodiment is thus implemented.

In the inspection apparatus <NUM>, the inspection system <NUM>, and the inspection method and the member repair method according to the present embodiment, the inspection apparatus <NUM> moves along the surface of the pipe T to measure the wall thickness of the pipe T, and wirelessly transmits detected information about the wall thickness to the control apparatus <NUM>. Since this eliminates the need for connecting a communication cable for transmitting the information detected by the inspection apparatus <NUM>, the moving range of the inspection apparatus <NUM> is not limited by the length or weight of the cable. In particular, even when the pipe T is installed high above the ground, the inspection range is not limited by the length or weight of the communication cable.

As described above, there is no need to connect a communication cable for controlling the inspection apparatus <NUM> or transmitting detected information about the wall thickness. This facilitates handling of the inspection apparatus <NUM> and the inspection system <NUM>. Also, the range of inspection of the pipe T is not limited by the length or weight of the communication cable. The pipe T can be easily and efficiently inspected for the flaw T0 over a wide range, and the efficiency of inspection can be improved.

The inspection apparatus <NUM> according to the present embodiment adopts an eddy current method. This eliminates the need for a water supply hose and a pump otherwise required for an ultrasonic inspection apparatus, facilitates handling of the inspection apparatus <NUM> and the inspection system <NUM>, and improves efficiency of inspection. In particular, the magnetizer <NUM>, which applies a static magnetic field to the inspection object member to produce eddy current, does not require power, because a permanent magnet is used as the magnetizer <NUM>.

Accordingly, the inspection apparatus <NUM> can be operated by simply supplying power to the moving mechanism <NUM>, the eddy current sensor <NUM>, the phase detector <NUM>, and the wireless transceiver <NUM>. The power consumed by the inspection apparatus <NUM> is significantly reduced. Thus, power to be consumed by the inspection apparatus <NUM> can be sufficiently supplied by the battery <NUM> in the housing <NUM> of the inspection apparatus <NUM>. Therefore, the inspection apparatus <NUM> according to the present embodiment can perform wireless inspection and does not require wired connection through a cable, such as a power supply cable, which is often required when an electromagnet is used as the magnetizer that produces eddy current, and thus, inspection can be carried out over a much wider range than with an inspection apparatus connected by wired connection.

The inspection apparatus <NUM> according to the present embodiment uses a magnetic crawler as the moving mechanism <NUM>. The magnetic crawler is firmly in contact with the pipe T having a curved surface and provides a large contact area. This ensures more stable attracting force than with a conventional moving mechanism that is composed of, for example, by magnetic wheels.

Therefore, the inspection apparatus <NUM> can stably run without falling off even at a bent portion or a stepped portion, such as the weld bead T1, of the pipe T. The inspection apparatus <NUM> can thus run without avoiding such a bent portion or a stepped portion. An elastic material is used to form a belt or shoes of the magnetic crawler composing the moving mechanism <NUM>, and magnets are embedded in the elastic members. Therefore, even when the magnetic crawler rubs over the surface of the pipe T during movement (particularly turning) of the inspection apparatus <NUM>, the inspection apparatus <NUM> can run without causing flaws, such as scratches and peeling, in the surface or coating thereon of the pipe T. It is thus possible to reduce damage to the pipe T caused by an inspection operation.

Using a magnetic crawler as the moving mechanism <NUM> can eliminate the need for a vacuum pump which is required to perform vacuum attraction as an attracting method. A significant reduction in power consumption can thus be achieved.

The inspection apparatus <NUM>, the inspection system <NUM>, and the inspection method according to the present embodiment may require installing the scaffold S when, as described above, a section of the pipe T defined by the flanges T2 is high above the ground. However, unlike in the case of using a conventional inspection apparatus with magnetic wheels, the scaffold S does not need to be built along the entire inspection object member. It is thus possible to significantly reduce the number of man-hours for installation of the scaffold S required to inspect the inspection object member.

The information about the wall thickness wirelessly transmitted from the inspection apparatus <NUM> is received by the control apparatus <NUM> installed at a distance from the inspection apparatus <NUM>. The inspector can thus carry out the inspection while constantly checking the result of the inspection through the control apparatus <NUM>.

Although an example of using an eddy-current inspection apparatus has been described in the aforementioned embodiments, the present invention is not limited to this. An inspection apparatus of another type, such as an ultrasonic inspection apparatus, may be used. In the case of using an ultrasonic inspection apparatus, for example, installing a small water tank in the inspection apparatus can eliminate the need for using a hose and a pump for supplying water to the inspection apparatus, make it possible to operate the inspection apparatus wirelessly, and make it possible to achieve substantially the same effects as the embodiments described above.

In the case of using an eddy-current inspection apparatus, an electromagnet, instead of a permanent magnet, may be used as the magnetizer. Also, instead of a magnetic crawler, a moving mechanism using vacuum attraction or magnetic wheels may be used as the moving mechanism.

In the aforementioned embodiments, an example has been described in which flaws, such as wall-thinning and cracking, caused by corrosion of or damage to the pipe T are detected and corrected. However, an inspection object member to be inspected and repaired in the present invention is not limited to this. For example, for various inspection object members including various hollow steel members such as tanks, non-hollow or solid steel members such as shaped steel members, and magnetic bodies, the present invention can be widely used to measure the thickness at an area constituting the surface, and to detect flaws.

Claim 1:
An inspection apparatus (<NUM>) comprising:
an inspection apparatus main body (<NUM>) having a moving mechanism (<NUM>) movable along a surface of an inspection object member (T);
a measuring device (<NUM>, <NUM>, <NUM>) provided on the inspection apparatus main body (<NUM>) and configured to measure a wall thickness of the inspection object member (T);
a transmitter (<NUM>) provided on the inspection apparatus main body (<NUM>) and configured to wirelessly transmit information about the wall thickness measured by the measuring device (<NUM>, <NUM>, <NUM>) to the outside; and
a battery (<NUM>) provided on the inspection apparatus main body (<NUM>) and configured to supply power to the moving mechanism (<NUM>), the measuring device (<NUM>, <NUM>, <NUM>), and the transmitter (<NUM>),
wherein the inspection object member (T) is a magnetic body; and
the measuring device (<NUM>, <NUM>, <NUM>) includes a magnetizer (<NUM>) configured to apply a static magnetic field to the inspection object member (T) to produce eddy current therein, an eddy current sensor (<NUM>) configured to measure the eddy current produced in the inspection object member (T), and a phase detector (<NUM>) configured to detect a phase of a waveform of the eddy current measured by the eddy current sensor (<NUM>),
characterized in that the magnetizer (<NUM>) is a permanent magnet.