JPH0247318B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an extra-pipe self-propelled device for holding and scanning a lightweight and simple sensor for non-destructive inspection of pipe welds and the like.

In order to ensure the safe operation of chemical plants, nuclear power plants, or hydraulic power plants, inspection and inspection of piping is essential, and by doing so, dangerous situations can be prevented. For this reason, regular maintenance and inspection are required, especially for pipes that flow toxic gases or liquids. In this kind of work, it is important to find flaws, cracks, wear, and abnormalities in the welded parts of the pipe. According to recent non-destructive testing technology using ultrasonic waves and eddy currents, the thickness of the pipe at the welded area can be measured with an accuracy of 1/100 millimeter simply by applying a probe to the outside of the pipe, making it possible to measure the thickness of the pipe at an accuracy of 1/100 mm without having to shut down the plant for inspection. Sometimes you can get away with it. Such examinations involve a major task of scanning the probe outside the tube. Traditionally, machines for this purpose include guide rails and
Alternatively, a device that wraps around a chain and moves along the chain has been considered. However, most of these have a cantilevered structure with poor center of gravity balance, and the need for the device to be strong means that it is relatively heavy and requires a large driving force. . In addition, it was difficult to adapt to changes in pipe diameter, and many efforts were required to maintain the device stably.

Furthermore, in order to conduct inspection over a wide area, it was troublesome to change the rails and chains. Further, when scanning a probe or the like in the tube axis direction, it is difficult to continuously scan the reducer portion or bent portion of the tube because the holding mechanism of the device lacks flexibility. To summarize the above, it can be said that the conventional extra-tube self-propelled devices have the following problems.

1 Difficulty driving in any direction 2 Difficult to scan over a wide area 3 heavy 4 Unable to respond to changes in pipe diameter and pipe shape 5 Affected by pipe slope 6 It takes a lot of time to prepare for driving.

The present invention does not use belts, chains, rails, etc., but uses mechanical deformation force to hold the main body outside the pipe, has at least three wheels in contact with the outer peripheral wall of the pipe, and uses the driving force of the wheels to hold the main body outside the pipe. Move along. Also,
By steering the wheels, it is possible to travel in any direction. The main body can be freely deformed by spring force, adapting to a wide range of changes in pipe diameter and shape. In addition, since the parts that require power such as motors are limited to driving the wheels and steering, it not only reduces the weight of the main body but also has a great effect on energy conservation.

From the above, the present invention solves the problems of conventional devices all at once, and becomes a very effective means for automating the work of inspecting and inspecting piping. The inventor is
Another application is pending for a self-propelled device outside the pipe, but this is mainly suitable for traveling around the outer circumference of the pipe. The present invention provides for this a device suitable for running the tube in the longitudinal direction. Hereinafter, the present invention will be specifically explained using Examples.

FIG. 1 shows a basic embodiment of the invention based on a two-arm opening mechanism. FIG. 2 is a side view of the embodiment of FIG. 1. The arms 1,1 are free to rotate around the pivot 2. 3 is an extension spring that acts to separate the two arms from each other. A substrate 8 that freely rotates around a pivot has a pair of support shafts 4, 4 equidistant from the pivot 2. The spindle 4 has wheels 5, 5 on both ends.
supports an axle 6 having a Further, the tips of the arms 1, 1 are respectively coupled to auxiliary arms 9, 9 located on the same side as the substrate 8. The auxiliary arm is directly connected to the support shaft 4 and supports an axle 6 having wheels at both ends. The 4 supporting axes are 4
A set of wheels (eight in total) are arranged in a direction that pushes the tube 12 in a plane parallel to the plane of motion of the arm. Since the extension force of the spring always acts on the arm, the wheel is pressed against the outer wall of the pipe, adapting to the size of the pipe. As a result, the arm with wheels (hereinafter referred to as the main body) is held on the outside of the tube. A portion of the wheels generates rotational force by the drive device 7, causing the main body to travel in the longitudinal direction of the tube. 10 is
NDE sensor 11 is a rod that guides 10.
10 and 11 are available in a wide variety of ways depending on the purpose of the main body, and there are many other ways to attach them to the main body.

FIG. 3 shows an embodiment based on an opening mechanism constructed using two sets of arms, each consisting of two parallel links of equal length. FIG. 4 is a plan view of the embodiment of FIG. 3. The two sets of arms are connected at one end to the same board 8, and at the other end to different boards 8, 8 on the same side as the board 8, and are arranged around the upper and lower pivots 2. rotate freely. Therefore, the three substrates are kept parallel. 3 is an extension spring that acts to separate the two sets of arms from each other. The substrates 8, 8, 8 connected to both ends of the two sets of arms are each provided with a support shaft 4. The support shaft 4 supports an axle 6 having wheels 5, 5 on both sides. The three support shafts 4, 4, 4 are arranged in a direction in which three sets of wheels (six in total) push the tube 12 in a plane parallel to the plane of motion of the arm. As in the embodiment of FIG.
Since the extension force always acts on the arm, the wheel adapts to the size of the tube and is pressed against the outer wall of the tube. the result,
The main body is held on the outside of the tube and is moved in the longitudinal direction of the tube by the rotational force of wheels controlled by a drive device 7. The sensor section 10 and its guide rod 11 are necessary when the main body is used for pipe inspection.
Since these are not directly related to running, they will be omitted in the following example.

In the embodiment shown in FIG. 3, two sets of arms are connected at one end to the same substrate 8 by four pivots 2, 2, 2, 2.
It is also possible to connect by two pivots 2,2.
Even in this case, the three substrates 8, 8, 8 are kept parallel.

In the embodiment shown in FIGS. 1 to 4, one end of two or two sets of arms freely rotates around a pivot to change the opening angle, and the arms extend and contract freely and have a tension biasing device in the middle. Using this, it is also possible to fix one end of the arm to the substrate and keep the opening angle unchanged. In this case, there is no need for a biasing device to pull the two arms or two sets of arms apart from each other.

FIG. 5 shows an embodiment using one arm. 6th
The figure is a side view of the embodiment of FIG. 5. arm 1
is a device 3 that is stretchable and generates a tensile force in the middle.
Equipped with. One end of the arm 1 is free to rotate around a pivot 2. Pivot 2 is coupled to substrate 8 . The base plate 8 has a pair of support shafts 4, 4 equidistant from the pivot shaft 2.
The support shaft 4 supports an axle 6 having wheels 5, 5 at both ends.

On the other hand, the other end of the arm 1 is coupled to an auxiliary arm 9 on the same side as the substrate 8. The auxiliary arm 9 is directly connected to the support shaft 4 and supports an axle 6 having wheels on both sides. The three supporting axes are 3
Sets (six in total) of wheels are arranged in a direction that pushes the tube in a plane parallel to the plane of motion of the arm. Since the tensile force of the spring 3 constantly acts on the arm, the wheel is pressed against the outer wall of the pipe, adapting to the size of the pipe. As a result, the main body is held outside the tube. Each side of the arm is provided with at least one wheel drive, so that the rotating force of these drives the body in the longitudinal direction of the tube.

The device 13 for detecting the intersection angle θ between the substrate and the arm is useful for controlling the drive devices 7 on both sides in a coordinated manner. For example, by actively controlling the drive of one device and passively controlling the other drive device so that the value of θ becomes a specific value, cooperative control of both wheels becomes possible.

In FIG. 5, the arms are free to rotate around the base plate, so at least one drive wheel is required on each side of the tube. However, the arm is fixed to the board (generally θ = 90°)
Then, it is possible to travel with just one driving wheel on either side, and by doing so, the rotation angle detection device 13 is also unnecessary, and the device can be simplified.

FIG. 7 shows a single arm embodiment with an increased number of wheels. This structure is symmetrical. The arm is telescopic and has a device 3 in the middle that generates a tensile force. Both sides of the arm 1 are each free to rotate around a pivot 2. Pivot 2 is coupled to substrate 8 . The base plate 8 has a pair of axles 4, 4 equidistant from the axis of rotation. The support shaft 4 is an axle 6 having wheels 5, 5 at both ends.
support. A total of four support shafts coupled to a pair of substrates 8, 8 are arranged in a direction in which four sets (eight in total) of wheels push the tube in a plane parallel to the plane of movement of the arms. The tensile force of the spring 3 acts to pull the pair of substrates together, so that the wheels are pressed against the outer wall of the tube in accordance with the size of the tube. As a result, the main body is held outside the tube. Each side of the arm is provided with at least one wheel drive 7, the rotational force of which drives the body in the longitudinal direction of the tube. a device 13 for detecting the intersection angle (θu and θd) between a pair of substrates and arms;
13 is useful for realizing coordinated control of the two-sided drives 7,7. For example, it is possible to rotate both wheels simultaneously and continuously so that θu=θd.

In FIG. 7, both sides of the arm 1 can freely rotate around the substrates 8, 8, but in order to simplify the main body,
It is also possible to have one end of the arm pivoted, the other end fixed, or both ends of the arm fixed to the substrate. However, the fixed angle between the arm and the board is generally 90°. In either case, the rotation angle detection devices 13, 13 are unnecessary, and there is no need to provide drive devices on both the upper and lower substrates.

In the embodiments shown in FIGS. 5, 6, and 7, there is only one arm, but this can be replaced with two parallel links to keep all the support shafts 4 parallel. In such a case, not only the strength of the main body is increased, but also stable holding is achieved.

The basic embodiments of the present invention have been described above, but the following five modifications and their effects can be obtained in common to all the embodiments.

The first is that by adopting wheels that allow for horizontal movement, the main body can flexibly adapt to the shape and size of the tube, and can travel not only in straight circular tubes but also outside tubes with bends and reducers. That's true.

Second, by appropriately determining the shapes of the arm 1, support shaft 4, and axle 6, adaptability to the shape of the tube can be improved.

Thirdly, by employing freely movable rotary joints or bending joints at the joint between the axle and the support shaft, the main body can easily travel even when the tube is bent. For example, by adopting the structure shown in FIG. 8 in which the T-shaped connection between the axle and the support shaft is changed to a Y-shaped connection, and the axle 6 is rotatable around the support shaft 4 by the rotary joint 14, the running condition of the main body can be improved. is improved as shown in FIG. 9a to b. That is, if the direction of the wheels deviates from the longitudinal direction of the tube, the moment created in the pair of wheels adaptively orients the wheels in that direction. The rotation and bending joints that are inserted into the connection between the wheel and the support shaft to make each wheel steered do not generally need to rotate over a wide range, so in some cases, there may be multiple rotations around the shaft. It may be sufficient to provide only a small amount of flexibility, and therefore it may be simply constructed using a spring or the like. Therefore, the traveling shown in FIG. 9b can be realized without using any special equipment.

Fourthly, by adding a semi-fixed or continuously variable steering device to at least one of the driving wheels, the main body travels in a spiral shape on the outside of the tube. Figure 10 shows the situation. α is the steering angle, 1
5 is the main body, and C is the running trajectory.

Part 5 is as shown in Figures 11 and 12, by changing the attachment angle of the wheel 5 to the axle 6 by 90 degrees.
This makes it easier to travel in the direction of the outer circumference of the tube. In this case, the cross-sectional shape of the pipe is limited to a shape close to a circle, but the pipe can be made by supporting the axle and support shaft on one side of the pipe as shown in the lower part of Figure 12 instead of integrating them. Even if the cross-sectional shape is not circular, the main body can be adaptively held outside the tube and can be moved in the direction of the outer circumference of the tube. However, in either case, it is necessary to use partially transversely movable wheels or omnidirectional wheels such as ball casters.

As detailed above, since the device of the present invention has a simple structure, those skilled in the art can make various design changes. For example, the biasing means 3 may be configured using not only a mechanical spring but also electromagnetic force, hydraulic pressure, pneumatic force, etc., and apply the biasing force proportionally or inversely according to the opening angle and amount of expansion and contraction of the arm. It is also possible to use a device that changes or has a control system that generates a constant biasing force. It is also possible to change the arm length stepwise or continuously depending on the thickness of the tube.

As for the wheels, it is also conceivable to drive two sets of wheels on the same board as driving wheels. Increasing the number of driving wheels increases the frictional force of the wheels, creating greater traction. In addition, when driving two sets of wheels as driving wheels, they are generally controlled by the same control signal, but if each wheel is provided with a dedicated drive device 7, it is possible to drive both sets of wheels asynchronously. It can be rotated and conflicts will not occur. If a differential gear device is used, one drive device 7
However, it is possible to drive two sets of wheels at the same time without stress.

Further, according to the present invention, it is possible to measure the traveling distance of the main body by providing a device for measuring the rotational speed of at least one driving wheel. In particular, in the embodiment shown in FIG. 7, as long as arm 1 has a means of knowing its own length, the length of the arm, the detection angle (θu and θd), and the travel distance detected by the wheels on each board side can be easily determined. It is also possible to calculate the shape and size of the tube based on various information.

(Effects) The present invention makes it possible to press the wheels on both sides against the opposing outer walls of the pipe, float and support the main body outside the pipe, and travel outside the pipe in the longitudinal direction. By using wheels that can skid or turn sideways while turning in the direction of travel, stable holding and running are possible even at locations where the pipe diameter changes, such as at the elbow, reducer, or nozzle mounting section. . Furthermore, by replacing the longitudinal drive wheels with circumferential drive wheels, it is possible to run not only in the longitudinal direction of the tube but also along the outer circumference.

Therefore, it is possible to obtain a device that can stably run a self-propelled vehicle on the outside of pipes that have changed in various ways, even though it has been considered difficult to run a self-propelled vehicle in the past. Therefore, this device can be used extremely effectively for scanning various types of equipment necessary for various operations such as monitoring, inspection, maintenance, and repair of piping at various plants and construction sites, and for transporting materials. . Moreover, its configuration is relatively simple, and in that sense it is sufficiently practical.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a front view of the first embodiment, FIG. 2 is a side view of the same, FIG. 3 is a front view of the second embodiment, and FIG. 4 is a front view of the same. 5 is a front view of the third embodiment, FIG. 6 is a side view of the same as above, FIG. 7 is a front view of the fourth embodiment, FIG. 8 is a front view of an example of the axle support, and FIG. Figures 9a and b are diagrams of running conditions outside the pipe, Figures 10a and b are diagrams of running conditions by steering, Figure 11 is a front view of another embodiment suitable for traveling around the outer circumference of the pipe, and Figure 12 is the same as above. represents a side view of. In the figure, 1 is an arm, 2 is a pivot, 3 is a biasing force generator, 4 is a support shaft, 5 is a wheel, 6 is an axle, 7 is a drive device, 8 is a board, 9 is an auxiliary arm, and 10 is an NDE sensor unit , 11 is a guide rod, 12 is a tube, 13 is a rotation angle detection device, 14 is a rotary joint, 15 is a main body of the device, θ is an intersection angle between the board and the arm, and C is a running trajectory.

Claims (1)

[Scope of Claims] 1. A base plate facing one side of the tube, and at least one arm having one end attached to the base plate and the other end facing the other side of the tube, the base plate facing the other side of the tube. The arm supports an axle having wheels at both ends that contact one side, and the other end of the arm supports an axle that has wheels at both ends that contact the other side of the tube. , a biasing device for pressing a wheel provided at the other end of the arm against each side of the tube, and at least one of the wheels is a driving wheel driven by a drive device. Self-propelled device. 2 In the extra-tube self-propelled device according to claim 1,
The axis of rotation of each wheel is perpendicular to the plane of motion of the arm. 3 In the extra-tube self-propelled device according to claim 1,
An extra-tubular self-propelled device in which the axis of rotation of each wheel is parallel to the plane of motion of the arm. 4. In the extrajudicial self-propelled device according to any one of claims 1 to 3, at least one of the wheels is a steering wheel, and the other wheels are wheels movable in all directions or wheels movable laterally. Extrajudicial self-propelled device.