JPS5932864A - Inspector for inner surface of pipe - Google Patents

Abstract

PURPOSE:To achieve a safe and quick inspection of a pipe by running a self- propelling truck equipped with a video camera and a detector through a pipe being remote-controlled monitoring a reproduced image with the reproduction of an image signal from the camera in a monitor chamber. CONSTITUTION:A detector 3 is mounted on a self-propelling truck 1 with a running mechanism 2 and moves along the axis of a pipe 7 reciprocatively turning in the circumferential direction thereof 7 to inspect the pipe wall. A detection signal is transmitted with a transmission circuit 13 and recorded on a recorder 4 in a monitor chamber. An image signal outputted from a video camera 10 is reproduced with an image device 15. An instruction signal of a centralized operator 6 operates various points 62 to be instructed. This enables repeated inspection of points suspected of corrosion with emphasis, monitoring a reproduced image of the image device 15 thereby improving the inspection efficiency remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for inspecting the corrosion state of large-diameter liquid or gas transfer pipes such as cargo oil pipes installed in oil tankers.

Oil tankers are equipped with cargo oil pipes made of cast steel pipes of various diameters to match the tank. Among these, the main line cargo oil pipes have a diameter of 600 to 700 mm, and the parastrine cargo oil pipes have a diameter of 400 mm. ~500mm. Recently, maintenance and management of these cargo oil pipes has become an important issue.

The causes of corrosion in these cargo oil pipes are chlorine ions in seawater, organic sulfur compounds such as inorganic sulfur compounds and thiophelemercaptans contained in crude oil, and sulfate ions contained in large amounts in the sludge that collects at the bottom of cargo oil pipes. During a voyage, cargo oil pipes are immersed in these corrosive liquids. Among these causes of corrosion, corrosion due to sludge is the most prominent.
It is known that corrosion of cargo oil pipes generally begins from the bottom.

Conventionally, corrosion has been inspected by applying ultrasonic waves or magnetism from the outside of cargo oil pipes to check for disturbances in reflected waves or eddy currents, but this method is time-consuming, takes a long time, and causes damage to pipes and equipment. There were problems such as the difficulty of conducting inspection work in a remote location.

The simplest and most reliable method is for an inspector to enter the cargo oil pipe and inspect it while crawling inside the cargo oil pipe, but the inside of a tanker's tank is affected by the outside air and seawater temperature, and is therefore hot or cold and narrow. However, the working environment was not acceptable, and there were cases where gas accumulated in the cargo oil pipes, which could be dangerous.

The present invention allows a self-propelled vehicle equipped with a video camera and a detector to travel through a pipe, reproduces and processes image signals from the video camera in a monitor room outside the pipe, and monitors the self-propelled vehicle while monitoring the reproduced images. By remote control from the room and at the same time automatically recording the detection signal from the detector on a recording device mounted on a self-propelled vehicle, pipes can be inspected safely and quickly, and if an abnormality is found in the reproduced image, the location can be detected. The purpose is to provide a device that can perform repeated and focused inspections.

A further object of the present invention is to provide a device that allows a self-propelled vehicle to run in a pipe while installing a recording device for detection signals from a detector in a monitoring room and automatically recording pipe inspection data in the recording device. do.

The block diagram of FIG. 1 shows the signal conversion process of the detector and the remote control.

The detector is installed on a self-propelled vehicle (1) equipped with a traveling mechanism (2), and is kept at a constant height (approximately 20 mm) from the inner inspection surface of the tube and rotates reciprocatingly in the circumferential direction of the tube. move in the direction of
The pipe wall is inspected by the width of the reciprocating rotation of the detector.

As the detector, a known magnetic flaw detection sensor having a built-in coil that generates magnetic lines of force and a coil that generates electromotive force due to changes in the lines of magnetic force can be used. A current is passed through the magnetic field generating coil,
A closed loop of magnetic field lines is formed passing through the tube wall and the two coils. If the tube wall is reduced in thickness or cracked due to corrosion, the magnetic field lines and current of the detector (3) will be disturbed.

In order to detect increases and decreases in the current, the output is amplified through a balance section (30) using a bridge circuit, etc., and the self-propelled vehicle (
1) The detection signal is automatically recorded on the automatic recording device (4) loaded on the vehicle.

The detector (3) is not limited to the magnetic detection method described above, and various types can be employed. For example, a magnetic field may be applied to the tube wall by a detector to generate eddy currents, and disturbances in the eddy currents may be detected at abnormal locations on the tube wall.

Alternatively, it is also possible to detect an abnormality in the tube wall by applying ultrasonic waves or a laser to the tube wall and detecting the phase difference in which the reflected wave is delayed at an abnormal location on the tube wall.

The self-propelled vehicle (1) is equipped with a video camera (10), which photographs the pipe wall within the inspection range by the detector (3) while illuminating it with a built-in lighting device. The image signal output from the video camera (10) is sent to a signal processing section (11), a modulation section (1
2), the signal is modulated into a signal according to the transmission circuit (13), and then transmitted.

In the onboard monitor room, the received signal from the transmission circuit (13) is passed through a demodulator (14) and reproduced by an image device (15). If necessary, an image recording device (16) is connected to the image device (15) to record on a magnetic tape.

Commands for the traveling mechanism of the self-propelled vehicle (1) to move forward, stop, and reverse; commands for the rotation device (5) that reciprocates the detector (3) in the circumferential direction to rotate or stop; A communication system using a transmission circuit (13) is configured to transmit commands to start or stop recording to the automatic recording device (4) to be loaded, and to turn on/off the switch of the central control device (6) in the monitoring room. The command signal due to OFF is sent to the converter (60)
The signal is converted and transmitted, passes through the transmission circuit (13), and is converted again at the demodulator (61) of the self-propelled vehicle (1).
Operate each applicable instruction location (62).

FIG. 2 shows another embodiment of the present invention, in which a recording device (4) for recording detection signals from a detector (3) is installed in a monitoring room outside the tube.

The detection signal is sent to the transmission circuit (13) via the balance section (30) and the modulation section (31), and then sent to the demodulation section (32) in the monitor room.
The data is automatically recorded on the recording device (4) through the process. Other parts designated by the same reference numerals as in FIG. 1 correspond to the constituent parts in FIG. 1, and therefore their explanations will be omitted.

FIG. 3 shows a situation in which the inner wall of a pipe is inspected using the apparatus according to the embodiment of the invention shown in FIG.

Cargo oil pipes (7) are fitted into sockets (70) every few tens of meters,
They are connected by a so-called mechanical joint into which a packing (71) is inserted.

The main line of the cargo oil pipe has branch pipes (72) at several locations. Before inspecting the cargo oil pipes for corrosion, cracks, etc., seawater is forced into the pipes to clean them and empty them. After that, parts of the pipe, such as branches, bends, joints, etc., are removed and opened, and the self-propelled vehicle (1) is set inside the pipe, and the inspection begins with the detector of the flaw detection device of the self-propelled vehicle (1). (3) is fixed to the lower end of an arm (33) that reciprocates in an inspection range of 60 to 180 degrees with respect to the circumferential direction of the tube. A cable reel (63) is installed outside the area, and a self-propelled vehicle (
1) is from the cable reel (63) to the transmission cable (6
4) Drive while pulling out.

The output signals from the video camera (10) and the detector (3) are transmitted via the cable (64) and the cable reel (
It is connected to the cable (66) from the onboard monitor room via a mechanical joint (65) provided in 63).
The reproduced image is displayed on the image device of the central control panel (6) in the monitor room, and is automatically recorded on the recording device (4) at the same time.

Further, command signals are transmitted to each part of the self-propelled vehicle (1) via cables (66) and (64) by operating switches on the central control panel (6).

The output signal of the video camera (10) is transferred to an external imaging device (1).
Various methods can be adopted as the transmission method to 5), and the output signal is modulated appropriately depending on the transmission method. The transmission circuit (13) is configured with a wire cable, and the image signal is modulated into an electric signal or an electric pulse signal and transmitted, and in the monitor room, the signal is converted back into an electric signal, and the reproduced image can be displayed on an imaging device. .

Alternatively, a photoelectric conversion device converts the output signal into a 10 nanosecond optical pulse signal, the transmission circuit (13) transmits it using an optical fiber cable, and converts the optical signal received in the monitoring room into an electrical signal to display an image. You can also play it. Alternatively, a parabolic antenna is installed at the opening of the self-propelled vehicle and the pipe, the output signal is modulated into microwaves and transmitted, and the received signal of the receiving side parabolic antenna is converted into an electrical signal to reproduce the image. You can also do it.

The output signal of the detector (3) is also converted into an electrical signal, optical pulse signal, microwave, etc. in accordance with the transmission of the output signal of the video camera, and is installed in the monitoring room using the same transmission circuit (13). Of course, it is possible to send a signal to the recording device (4) that is located there.

It is also possible to transmit command signals from the central control unit in the monitor room to the self-propelled vehicle using a transmission circuit, but transmitting and receiving antennas are placed at the self-propelled vehicle and the opening of the pipe, respectively, to transmit command signals. It is also possible to communicate by converting it into a radio wave signal.

As shown in Figures 4 and 5, the self-propelled vehicle (1) is equipped with a trolley (1).
7) is equipped with a traveling device (2) equipped with endless tracks (20) (20), and the rotation of the loading motor (21) is regulated by a remote control signal from the monitor room.
Makes the traveling device move forward, backward, and stop.

The traveling device consists of drive pulleys (2) provided at the front and rear of the trolley (17).
2) An endless track (20) made of an endless belt is stretched between driven pulleys (23), and the lower rail has a roller (24) at its tip and a base end attached to a trolley. A plurality of pivoted support rods (25) are arranged in parallel and facing each other. Each support rod (25) has a lower end inclined toward the rear of the truck, and has a support plate (26) projecting from the side wall of the truck and a receiving plate (27) projecting horizontally from each support rod (25).
A compression spring (28) is interposed between the spring (28) and the spring (28).
The cart (17) is lifted by the repulsive force of. The elastic force of the spring (28) can be adjusted by adjusting means (not shown) provided on the support plate (26) and the receiving plate (27), and the spring (28) at the center of the trolley can be adjusted to be the strongest. with the springs (28) at both ends to strongly support the trolley (17).
a) (28a) is the weakest, and the middle spring (28b) (
28b) is slightly more regulated. Therefore, even if the endless track (20) runs over a foreign object attached to the pipe wall while traveling, the shock to the detector (3), recording device (4), and video camera (10) to be loaded is minimized. It can be relieved.

Furthermore, on the forward extension of the lower transition side of the endless track (20) on the bogie side, a knife blade (19) is installed close to the pipe wall at the lower end of the bracket (18) protruding from the bogie, and is used for washing with water before inspection. The purpose is to remove any adhesion that remains after treatment and reduce the impact on self-propelled vehicles.

At the front of the trolley, there is a mounting plate (
50) Place the four guide posts (51) vertically upwards,
A table (52) equipped with an inspection device is provided along the guide post (51) so as to be movable up and down. table(
A screw shaft (53) arranged parallel to the guide post (51) is engaged with the table (52), and the height of the table (52) can be arbitrarily adjusted by rotating the screw shaft (53) in forward and reverse directions.

A motor (54) with a speed reducer is installed on the table (52), and the output shaft of the motor is connected to a rotating shaft (57) supported by a pillow block (56) on the table via a crank mechanism (55). is connected to.

An arm (33) slightly longer than the radius of the tube to be inspected is attached to the tip of the rotating shaft (57), and a detector (3) is attached to the lower end of the arm (33). The arm (33) is slidably engaged with a block (34) fixed to the tip of the rotating shaft, and has a threaded shaft (35) hanging from the upper end of the arm (33).
) passes through the block (34) and is rotatably disposed on the arm (33).

By rotating the knob (36) at the upper end of the screw shaft (35) forward and backward, the screw shaft (35) rotates while engaging with the block (34), and the arm (33) can be raised and lowered.

The self-propelled vehicle (1) can further be equipped with a recording device (4) and a power source (40) such as a battery, and the power source (40) powers the motor (21) of the traveling device (2) and the motor (54) of the inspection device. ), recording device (4) and video camera (10)
However, the power source (40) may not be installed in the self-propelled vehicle, but a power line may be integrated into the transmission circuit (13) and power may be supplied from outside the area.

The video camera (10) is attached to a mounting plate (50) and a table (5).
2) By the built-in lamp installed in the space between
It irradiates the transition range of the detector (3) at the tip of the arm (33), images the condition of the tube wall surface, and sends an output signal to the monitor room on board.

However, when inspecting the inner surface of a tube, the table (52) is raised and lowered by adjusting the screw shaft (53), and the rotation shaft (57)
corresponds to the height of the center line of the tube to be inspected. Next, turn the knob (36) at the upper end of the arm (33) to adjust the detector (3) to a certain height (approximately 20 mm) from the surface to be inspected.

Once the self-propelled vehicle (1) is installed on the inner wall of the pipe (7), the motor (54) is driven to rotate the arm (33) back and forth at an appropriate speed (for example, about 2 times per second). At the same time, the traveling device motor (21) is driven to move the endless track (20) and advance the self-propelled vehicle (1) in the tube axis direction.

In the monitoring room, the piping diagram is compared with the image sent from the video camera, and the raw image is monitored while constantly confirming the inspection position of the self-propelled vehicle (1).

Since the rotation axis (57) of the arm (33) rotates in alignment with the central axis of the tube, the detector (3) can be swiveled horizontally in the circumferential direction of the tube without changing its height from the inspection surface. While moving in the axial direction of the tube, the inner surface of the tube is inspected in the range of about 60 to 180 degrees.

If the detector (3) forms a closed-loop magnetic field line magnetic circuit including the pipe wall, and detects disturbances in the magnetic field lines and issues an output signal, the detector (3) will detect disturbances in the magnetic field lines even if the pipe wall is normal during the transition. Since the magnetic lines of force are not disturbed and form a closed loop with constant strength, a constant voltage is recorded on the recording surface of the recording device (4) as shown in FIG. 6 (point A).

If cracks or corrosion occur on the pipe wall, the detector (3
) passes through an abnormal point, the resistance of the magnetic circuit increases,
Disturbances in the lines of magnetic force appear on the recording surface as the strength and weakness of the voltage (
point B).

Since the time for the detector (3) to cross the abnormal location is almost instantaneous, the output signal appears in the form of a pulse on the recording surface. If the rotation axis (57) of the arm (33) is deviated from the center axis of the tube, the detector (3)
approaches and moves away from the surface to be inspected, causing fluctuations in the strength of the magnetic circuit resistance, but this must appear as a large positive wave-like curve on the recording surface, so it is a pulse-like signal that indicates an abnormality in the tube wall. can be clearly identified.

If the strength of the voltage is calibrated to the distance between the magnetic detector (3) and the tube wall, the height of the pulse wave (point B) will correspond to the depth of the crack or corrosion, so the recording surface By observing the pulse waves appearing in the pipe, it is possible to estimate the extent of cracking and corrosion on the pipe wall.

In addition, since the image reproduced by the image device (15) can be monitored in the monitor room and areas suspected of corrosion can be repeatedly inspected, inspection efficiency is significantly improved. After the inspection, the self-propelled vehicle is returned to the pipe opening, and then the recording medium (recording paper, magnetic tape, semiconductor, etc.) is removed from the recording device (4).
Take it out and check the recorded signal.

In the case of the embodiment shown in FIG. 2, it is possible to monitor the image in the monitor room and simultaneously check and judge the output signal of the detector, so it is easy to study.

If the inspection concludes that the pipe is dangerous, the pipe containing the abnormal part can be replaced with a new one to avoid an accident.

One end of the rope (59) is stopped at the self-propelled vehicle (1), and the rope (59) is pulled while moving. Therefore, in the unlikely event that a self-propelled vehicle stops in the middle of the pipe due to a malfunction, the rope (
59) and retrieve the self-propelled vehicle.

As described above, the present invention equips a self-propelled vehicle with a video camera,
Because it migrates through the pipe, it can be inspected simply, safely and quickly, and by monitoring images, it is possible to focus inspections on areas suspected of corrosion or cracks, and collect detection data, resulting in more accurate inspections. It has many excellent effects, such as making it easier to judge the danger level of pipes.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of the present invention, FIG. 2 is an explanatory diagram of another embodiment of the same as above, FIG. 5 is a left side view of the self-propelled vehicle, and FIG. 6 is the recorded data of the recording device. (1)...Self-propelled car (10)...Video camera (1)
3)...Transmission circuit (2)...Recording device (20)...
・Infinite track (3)...detector (4)...recording device

Claims (1)

[Claims] ■ A self-propelled vehicle equipped with a traveling device, a video camera disposed on the self-propelled vehicle to image the surface condition of the inspection surface, and one end of an arm having a length approximately equal to the radius of the tube. It is pivoted to the self-propelled vehicle, and a detector for detecting abnormalities such as corrosion and cracks in the pipe is attached to the other end of the arm.The reciprocating rotation device installed on the self-propelled vehicle is linked to the arm, and the detector is attached to the inner surface of the pipe. an inspection device that inspects the tube by moving it back and forth in the circumferential direction along the tube, a transmission circuit that transmits the image signal of the video camera to a monitor room outside the tube, and an image device that is installed in the monitor room and reproduces the image signal. and a recording device installed on a self-propelled vehicle to record detection signals. ■The detection tube is one that passes current through a built-in coil to form a closed loop of magnetic lines of force passing through the detector and the tube wall, and detects disturbances in the lines of magnetic force due to abnormalities in the tube wall.Claim 1
Section equipment. (2) The device according to claim 1 or 2, wherein the transmission circuit is a wire cable that converts the image signal into an electrical signal and sends the signal to the image device via the wire cable. (2) The device according to claim 1 or 2, wherein the transmission circuit is an optical fiber, converts the image signal into a light pulse signal, and sends the signal to the image device via the optical fiber. ■ A self-propelled vehicle equipped with a traveling mechanism, a video camera placed on the self-propelled vehicle to image the surface condition of the inspection surface, and one end of an arm with a length approximately equal to the radius of the tube pivoted to the self-propelled vehicle. A detector is attached to the other end of the arm to detect abnormalities such as corrosion or cracks in the pipe, and a reciprocating device installed on the self-propelled vehicle is connected to the arm to reciprocate in the circumferential direction along the inner surface of the pipe. An inspection device that advances the tube to inspect the tube, a transmission circuit that transmits the image signal of the video camera and the detection signal of the detector to a monitor room outside the tube, an image device installed in the monitor room that reproduces the image signal, and a monitor. A tube inner surface inspection device consisting of a recording device installed in a chamber and recording detection signals. ■The detector is a device that passes current through a built-in coil to form a closed loop of magnetic lines of force passing through the detector and the tube wall, and detects disturbances in the lines of magnetic force due to abnormalities in the tube wall.Claim 5
Section equipment. (2) The device according to claim 5 or 6, wherein the transmission circuit is a wire cable that converts the image signal into an electrical signal and sends the signal to the image device via the wire cable. (2) The device according to claim 5 or 6, wherein the transmission circuit is an optical fiber, converts the image signal into a pulse signal, and sends the signal to the image device via the optical fiber.