JPH0152231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an outside-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. Recent non-destructive testing technology using ultrasonic waves and eddy currents makes it possible to measure pipe thickness at welded areas with an accuracy of 1/100 millimeter simply by applying a probe to the outside of the pipe, making it possible to inspect plants for inspection In some cases, it may not be necessary to stop. Such inspections involve a major task of scanning the probe outside the conduit.
Conventionally, as a machine for doing this, a device has been considered in which a guide rail or chain is wound around a pipe and the pipe moves along this. 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 self-propelled devices outside the pipeline 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 uses mechanical deformation force to hold the main body outside the pipe without using belts, chains, rails, etc., and at least three wheels are brought into contact with the outer peripheral wall of the pipe, and the driving force of the wheels is Move by. Additionally, 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 and steering the wheels, it is possible to reduce the weight of the main body.
It also has a great effect on energy saving.

In view of the above, the present invention solves all the problems of the conventional apparatus at once and provides a very effective means for automating the work of inspecting and inspecting piping. Hereinafter, the present invention will be specifically explained using Examples.

FIG. 1 shows an embodiment using a scissor mechanism. FIG. 2 is a side view of the embodiment of FIG. 1. Arms 1 with each end rotating freely around a pivot 3
and 2 are given an urging force and attract each other. In this example, the spring 6 is used to apply the biasing force.
For this purpose, each arm is provided with a portion that connects each end of the spring. The arm 1 is provided with one wheel 4, and the arm 2 is provided with two wheels 4, 4 on both sides. The rotational axes of the wheels are all in the same direction as the pivot 3, that is, perpendicular to the plane of motion of the arms 1 and 2. three wheels 4,
4, 4, a force that presses the conduit 7 due to the urging force of the spring 6 acts on the outer periphery at positions approximately equally spaced in the circumferential direction, and a scissor mechanism (hereinafter referred to as the main body) by the arms 1 and 2 is formed. is held on the outer periphery of the conduit 7. When the drive device 9 applies rotational force to at least one of the three wheels, the main body travels around the outer circumference of the tube. In Figure 2, 8 is the welded part of the pipe to be tested, and 10 is the NDE
The sensor section 11 is a rod that guides the sensor section 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. Since these are not directly related to running, they will be omitted in the following example.

3 and 4 are examples in which the arm shape in FIG. 1 is changed. In other words, in Figure 1, arms 1 and 2 are both straight, whereas in Figure 3, arms 1 and 2 are both curved, and in Figure 4, arm 2 is straight and arm 1 is curved. be. These are used depending on the driving style of the wheels, the mounting situation of the test equipment, the shape of the tube, etc. It is considered that FIG. 3 is suitable for downsizing the main body.

FIG. 5 is an example of a symmetrical structure. The two arms 1 and 2 are identical in shape and size, each one end being pivotally connected to a pivot 3, and each other end being connected to a wheel 4. A spring biasing device 6 provides a tensile force between the two arms. The two links 12, 12 are the arms 1
A four-bar link (pantograph) mechanism is formed by using a part of the links 12 and 2, and has wheels 4 at a position symmetrical to the pivot 3, that is, at the intersection of the links 12, 12. This wheel tends to move away from the pivot 3 due to the biasing force of the spring 6. On the other hand, the wheels 4, 4 at the end of the arms tend to attract each other due to the same biasing force, so that the wheels 4, 4, 4 press against the outer periphery of the conduit 7 at approximately equal intervals in the circumferential direction. Therefore, the main body is held on the outer periphery of the main body and runs along the outer periphery of the conduit by applying rotational force to at least one wheel,
Change the direction of movement by changing the direction of rotation.

FIG. 6 shows an example in which the main body is held in the conduit using three arms. Both ends of the main arm 1 are provided with pivot shafts 3, 3 that are parallel to each other and perpendicular to the main arm 1, and auxiliary arms 1', 1' are pivotally connected to each of the pivot shafts. Each of the auxiliary arms 1', 1' is provided with one wheel 4, 4 at its tip, and the main arm is provided with a wheel 4 at its intermediate portion. The auxiliary arms 1', 1' are biased by a spring 6 so as to attract the main arm 1 to each other.
Therefore, when a conduit is inserted into the area surrounded by the main arm 1 and the auxiliary arms 1', 1', the outer circumference of the conduit is approximately equally spaced in the circumferential direction so that the wheels 4, 4, 4 sandwich it. The main body is held on the outer periphery of the conduit by pressing at the spaced positions.
Even if the size or shape of the pipe changes, the main body is held on the outer periphery of the pipe by the biasing force of the spring 6, which is no different from the previous embodiments. 3 wheels 4,
The fact that the main body can travel around the outer circumference by applying at least one rotational force of 4, 4 is exactly the same as in the previous example. In order to stably hold the main body by supporting the outer periphery of the conduit with many wheels, it is sufficient to provide two wheels close to each other on the main arm 1, as in the embodiment shown in FIG.

Furthermore, the urging devices 6 in the embodiments shown in FIGS. 6 and 7 can be combined into one. FIG. 8 shows an embodiment in that case. This is basically similar to the embodiment of FIG. 6, but the auxiliary arms 1',
1' are mechanically coupled so that their rotational directions are opposite to each other. Belts, gears, levers, chains, etc. are conceivable as means of connection, but the figure shows two pulleys 1 integrally connected to auxiliary arms 1', 1'.
3 and 13 are joined together by a belt 14. By doing this, the embodiment shown in FIG. 8 can be said to be completely similar in function to the embodiment shown in FIG. 6. It is also clear that stable holding can be achieved by providing two wheels on the arm 1 (see Figure 7).

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

First, by replacing at least one wheel attached to the arm with a set of wheels provided at both ends of the vehicle frame, the number of contact points between the main body and the tube increases, and the main body can be held more stably. In this case, when two wheels are placed on the same rotation axis (Figure 9)
and a case where the bogie truck 4a or the like is arranged on the same rotating surface (FIG. 10). In both cases, the axis of rotation of the wheel is perpendicular to the plane of motion of the arms 1, 2.

Second, by appropriately determining the shapes of arms 1, 1', and 2, the adaptability of holding to the shape of the pipe can be increased. This also helps in making the main body more compact, as is clear from Fig. 3.

Thirdly, by adding a steering device to at least one wheel that changes the traveling direction semi-fixedly or continuously, the main body can be made to travel in a spiral shape outside the pipe. Figure 11 a, b
indicates the situation. α is the steering angle, 15 is the main body,
C is the travel trajectory. However, in this case, the wheels other than the steering wheel are wheels that can slide sideways,
Alternatively, the wheel 4' must be movable in all directions, such as a ball caster.

Fourthly, by changing the attachment angle of the wheels 4 to the arms 1 and 2 by 90 degrees as shown in FIG. 12, the tube can be easily moved in the longitudinal direction. It goes without saying that in this case some of the wheels must be able to move laterally.

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 6 is configured using not only a mechanical spring but also electromagnetic force, hydraulic pressure, pneumatic pressure, etc., and the biasing force changes proportionally or inversely proportionally depending on the opening angle of the arm. It is possible to use both a type with a control system that generates a constant urging force and a type with a control system that generates a constant urging 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 wheels on the same arm as driving wheels. Increasing the number of driving wheels increases the frictional force of the wheels and can generate a large traction force. In addition, when multiple wheels are driven together as driving wheels, they are generally controlled by the same control signal, but if each wheel is provided with a dedicated drive device 9, multiple wheels can be rotated asynchronously. Yes, and there will be no competition. If a differential gear is used, one drive device can simultaneously drive two wheels without stress.

Furthermore, the present invention includes a device for measuring the rotational speed of at least one driving wheel, thereby making it possible to measure the distance traveled by the main body. It is also possible to measure the thickness and shape of the tube by adding a device that detects the opening angle between the two arms.

(Effects of the Invention) Since the present invention positions and holds the main body at approximately equal intervals around the outer circumference of the pipe, the resistance during driving is small and does not require large driving force unlike conventional cantilever structure devices. . Moreover, by replacing the conduit outer circumferential drive wheels with longitudinal direction drive wheels, it is possible to travel not only around the conduit outer circumference but also in the longitudinal direction.

Since the entire device is lightweight, a stopper can be easily attached to prevent it from falling on diagonal or vertical pipes, and it is possible to stably hold and run the pipe in any position. The scissoring force of the scissor mechanism allows stable holding and running even at locations where the pipe diameter changes, such as the elbow portion, reducer portion, or nozzle attachment portion.

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 extremely effectively used for scanning or transporting various equipment necessary for various operations such as monitoring, inspection, maintenance, and repair of piping at various plants, construction sites, and the like. Moreover, its configuration is relatively simple, and in that sense it is sufficiently practical.

In short, the present invention arranges at least three wheels on the scissoring surface of the arm constituting the scissoring mechanism, presses the wheels against the pipe by force of the scissors, and as a result, holds the main body on the outer circumference of the pipe, and at least one This system provides a device that applies rotational force to wheels to travel along the outer periphery of the pipe, which not only eliminates the need for conventional rails and chains, but also uses steering wheels to move not only around the outer periphery of the pipe but also in the longitudinal direction of the pipe. It has extremely high practical value in realizing a device that automatically performs probe scanning, etc. when testing tube welds etc. for flaw detection.

[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, FIG. 4, FIG. 5, FIG. 6, and FIG. 7 and 8 are front views of the second, third, fourth, fifth, sixth, and seventh embodiments, FIG. 9 is a side view of the eighth embodiment, and FIG. 10 is a ninth embodiment. FIG. 11a is a side view of the 10th embodiment, FIG. 11b is a running situation diagram of the same as above, and FIG.
FIG. 2 shows a front view of another embodiment suitable for longitudinal running. In the figure, 1, 1', 2 are arms, 3 is a pivot,
4, 4' are wheels, 5 is a spring connection point, 6 is a tension spring, 7 is a conduit, 8 is a welded part, 9 is a drive device, 1
0 represents the NDE sensor section, 11 the guide rod, 12 the link, 13 the pulley, 14 the belt, 15 the device body, α the steering angle, and C the travel trajectory.

Claims (1)

[Scope of Claims] 1. At least two arms, each end of which is pivoted so that it can freely rotate around a pivot, and a pipe that is supported by the two arms and that is used for the pipe to run. At least three wheels in contact with the outside, and a biasing device that applies a biasing force to attract each other between the two arms and sandwich the pipe between the three wheels; Both are self-propelled devices outside the pipeline that travel outside the pipeline using one rotational force. 2. The out-of-pipe self-propelled device according to claim 1, wherein the rotation axis of each wheel is oriented perpendicular to the plane of motion of the arm. 3. The out-of-pipe self-propelled device according to claim 1, wherein the axis of rotation of each wheel is on the plane of movement of the arm or parallel to the plane of movement of the arm. 4. In the out-of-pipe 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. A self-propelled device outside the pipeline.