Movable body

Abstract

To provide a movable body capable of correcting a changed posture even when a posture is changed in a process of moving in a pipe conduit through which pressurized liquid circulates.SOLUTION: A movable body 1 has a specific gravity substantially equal to a specific gravity of pressurized liquid 3 flowing in a pipe conduit 2, is formed in such a slender shape that a lengthwise dimension is larger than a thickness dimension, and moves along a central axis of the pipe conduit along with the liquid flowing in the pipe conduit. The movable body is formed such that fluid resistance against liquid on one end part side in a lengthwise direction and fluid resistance against liquid on the other end part side are different from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a moving body that moves together with a liquid inside a pipeline through which pressurized liquid flows, and more particularly to a moving body that can correct its attitude even if the attitude changes during the movement. [Background technology]

[0002] Underground pipelines are laid through which various liquids under pressure, including drinking water, industrial water, and agricultural water, flow. These pipelines are constructed by arranging pipes of standard sizes and connecting the pipes to each other with joints that have a structure corresponding to the liquid that flows through them, ensuring liquid-tightness. For example, in the case of pipelines for industrial water or agricultural water, watertightness is ensured by connecting the ends of concrete pipes with packing. In addition, in the case of pipelines for drinking water, watertightness is ensured by bolting the ends of cast iron pipes with packing.

[0003] Pipes laid underground are subject to various forces, such as vibrations caused by vehicles traveling on the road surface, forces caused by land subsidence, and forces in the direction of the pipe laying or in a direction crossing the pipe laying direction during earthquakes. These forces acting on the pipes can cause gaps to form as the pipe joints separate, or deterioration over long periods of use can cause cracks to form in the pipe walls.

[0004] If gaps at joints or cracks in the pipe walls occur in a pipeline through which pressurized liquid flows, the liquid will leak into the ground, causing problems corresponding to the nature of the liquid. For example, in the case of industrial water, agricultural water, or drinking water, these waters are collected from the water source and treated according to their respective purposes, and leakage of water results in waste of treatment costs. In addition, leakage from the pipeline may weaken the ground around the pipeline or cause soil changes. In particular, if the liquid contains oil components, it may cause environmental pollution.

[0005] When repairing a leak that has occurred in a pipeline, if the difference in distance between the detected leak location and the actual leak location is large, the length to be excavated will be large, and the time and effort required for repair will be large, so it is necessary to detect the leak location as accurately as possible. In order to detect the presence and location of a leak in such a pipeline, leak detection methods and devices described in Patent Documents 1 and 2 have been proposed. These technologies detect the leak location by collecting and recording sound transmitted through a liquid by a moving object moving inside the pipeline, and detecting the position of the moving object when the sound was collected.

[0006] In the invention described in Patent Document 1, the moving body is configured to have a specific gravity approximately equal to that of the liquid flowing in the pipeline, and is equipped with a sound-collecting microphone, a recorder, a gyro, and an acceleration sensor inside. Therefore, the moving body can move approximately along the center of the pipeline. The position of the moving body in the pipeline is detected by analyzing the measured values ​​of each sensor from the time the moving body is inserted into the pipeline.

[0007] In the invention described in Patent Document 2, the moving object is configured to have a specific gravity approximately equal to that of the liquid flowing inside the pipeline, and two sound collecting microphones are arranged inside, facing the upstream and downstream sides in the moving direction. As with Patent Document 1, the moving position of the moving object is detected by equipping the moving object with a gyro and acceleration sensor, and analyzing the measured values ​​of each sensor from the time it is inserted into the pipeline. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6919884 [Patent Document 2] Patent No. 7169577 Summary of the Invention [Problem to be solved by the invention]

[0009] In order to detect the location of a leak in a pipeline using a moving object that moves with the liquid, it is necessary to accurately know the location of the moving object in the pipeline. By accurately knowing the location of the moving object, it is possible to pinpoint the location of the leak with high accuracy from the sounds collected during the movement of the moving object.

[0010] In the inventions described in the above-mentioned Patent Documents 1 and 2, it is possible to collect and record the sound transmitted through the liquid while the moving body moves together with the liquid in the pipeline. In particular, since the moving body is formed as a cylindrical body having the same specific gravity as the liquid flowing through the pipeline, it can move through the pipeline at approximately the same speed as the liquid and while always maintaining the same posture.

[0011] However, there are some problems. In the process of the moving body moving in the pipeline, the longitudinal axis of the moving body may be inclined with respect to the central axis of the pipeline, and the moving body may move in this inclined posture. For example, when the moving body passes through a bent part of the pipeline or a part where some obstacle exists, a part of the moving body may come into contact with the pipe wall, a valve part, or an obstacle, and the posture may change so that it is inclined with respect to the axis of the pipeline. In particular, in the case of an agricultural water pipeline, leaves, branches, garbage, etc. of trees may be mixed in, and these may become obstacles and the moving body may collide with them, causing a change in posture. In this case, the moving speed of the moving body will change, which may affect the recording accuracy of the sound transmitted through the liquid.

[0012] This problem does not only apply to mobile objects equipped with devices capable of detecting leaks in pipelines, but also applies to any mobile object that is elongated and has a specific gravity approximately equal to that of liquid, such as a mobile object equipped with devices for photographing the inner surface of a pipeline.

[0013] The object of the present invention is to provide a moving body that can be corrected to a preferred posture in which the longitudinal direction is approximately at the center of the pipeline and approximately parallel to the axial direction, even if the posture of the moving body moving within a pipeline through which pressurized liquid flows changes. [Means for solving the problem]

[0014] A representative moving body according to the present invention for solving the above problems is a moving body that has a specific gravity approximately equal to the specific gravity of a liquid under pressure flowing through a pipeline, is formed in an elongated shape with a length dimension greater than its thickness dimension, and moves along the central axis of the pipeline together with the liquid flowing through the pipeline, and is formed so that the fluid resistance to the liquid at one end in the longitudinal direction is different from the fluid resistance to the liquid at the other end. Effect of the Invention

[0015] The movable body according to the present invention is formed so that one end of the movable body in the longitudinal direction has different fluid resistance to the liquid from the other end of the movable body, and therefore, when the movable body changes in position so as to be inclined with respect to the central axis of the pipeline, the movable body can be corrected to a preferable position in which the longitudinal direction is approximately at the center of the pipeline and approximately parallel to the axial direction. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a schematic diagram illustrating a configuration of a moving body according to the present embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating a method for detecting leakage in a pipeline. [Diagram 3] 1A and 1B are diagrams illustrating an example of a change in the attitude of a moving object. [Figure 4] FIG. 1 is a diagram illustrating an example of a resistor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The moving body according to the present invention is inserted into a pipeline through which a pressurized liquid flows, and is configured to be elongated and have a specific gravity approximately equal to that of the liquid. If the moving body is tilted with respect to the central axis of the pipeline while moving together with the liquid through the pipeline, it is configured to be able to correct the tilt to a direction along the central axis of the pipeline. The moving body is configured as, for example, a device for detecting leakage in a pipeline or a device for photographing the inside of a pipeline, depending on the function of the device arranged inside. In this way, the moving body can be configured to perform different functions. Below, the moving body will be described as a moving body having a device for detecting leakage in a pipeline arranged inside it, as a representative example.

[0018] The moving body is advantageously used to detect the presence or absence of a leak in a pipeline through which a pressurized liquid flows, and, if a leak does occur, to detect its location. The moving body has a specific gravity set to be approximately the same as that of the liquid, and is capable of moving together with the liquid flowing through the pipeline. The moving body is configured to collect sound transmitted through the liquid during the process of moving together with the liquid inside the pipeline, and record the sound together with the time.

[0019] The movable body has internal devices arranged so that the weight of the elongated body in the longitudinal direction can be balanced. The center of gravity of the movable body is set at the center in the longitudinal direction, slightly below the center of the cross section. The movable body configured in this way moves in the longitudinal direction parallel to the central axis of the pipeline, does not rotate around the center of the cross section during the movement, and can move stably with the center of gravity in the cross section always at a position below the center of the cross section.

[0020] Since liquid under pressure flows through a pipeline when it is full, a valve plug is installed at a preset position in the pipeline to discharge gas separated in the pipeline or to collect liquid. When detecting the presence and location of a leak in a pipeline, a moving object is inserted from a valve plug set in the pipeline to be detected as a detection start point and the time is recorded, and when the moving object that has moved with the liquid reaches the detection end point, it is removed from the pipeline and the time is recorded. Based on these recorded times, the presence and location of a leak in the target pipeline can be detected from the recorded sound and the position of the moving object.

[0021] The movable body is inserted into the pipe through the valve plug portion installed in the pipe. For this reason, the movable body is formed in an elongated shape with a thickness smaller than the diameter of the pipe constituting the valve plug portion, and a length capable of accommodating the sound recording member, the clock, and a number of functional parts selected as necessary, but larger than the thickness. Such a shape is preferably a cylinder, and the front and rear ends are preferably spherical.

[0022] The dimensions of the moving body can be set according to the diameter of the pipeline to which it is to be applied, and are not limited thereto. For example, when the target pipeline is a water pipeline, the diameter of the pipe constituting the valve plug portion for inserting or removing the moving body is 75 mm, so the outer diameter of the moving body is about 50 mm to 70 mm, and the length corresponds to the configuration and dimensions of the parts to be accommodated, but is preferably about 100 mm to 300 mm. In particular, by arranging the devices to be accommodated inside the moving body so that their weight is concentrated at the bottom, it is possible to reduce rolling that may occur during movement inside the pipeline.

[0023] The configuration of the leak detection member arranged on the moving body is not particularly limited, and may be, for example, a member that detects leaks by collecting and recording the sound transmitted through a liquid, or a member that detects leaks by photographing the inner surface of a pipeline. In particular, when collecting and recording sound, a microphone and a recording medium that can reliably collect the sound transmitted through a liquid are sufficient. Although one set of such microphones and recording media is sufficient, the sound generated in the pipeline is often reflected by the pipe wall and does not produce a clear peak. For this reason, it is preferable to arrange two sets of sound recording members consisting of two sets of microphones with different directivities and two sets of recording media corresponding to the respective microphones.

[0024] The moving body is formed so that the fluid resistance to the liquid at one end in the longitudinal direction is different from the fluid resistance to the liquid at the other end (hereinafter simply referred to as "fluid resistance"). In particular, methods for increasing the fluid resistance of the moving body include attaching a resistor that increases the fluid resistance to the outer periphery, or increasing the surface roughness of the outer periphery. By selectively adopting the above methods to either end of the moving body, it is possible to realize different fluid resistances.

[0025] One end of the moving body, for example the downstream side in the moving direction (hereinafter also referred to as the "front end"), and the other end, for example the upstream side in the moving direction (hereinafter also referred to as the "rear end"), are made to have different fluid resistances. In cases where the sound recording member, clock, and other functional parts arranged inside the moving body have directionality, the fluid resistance at the end on the upstream side in the moving direction, i.e., the rear end, is made larger.

[0026] The shape of the resistor attached to the moving body to increase the fluid resistance is not particularly limited. The resistor may be any shape that can provide resistance to the liquid, and is preferably shaped so that the moving body does not frequently come into contact with the pipe wall when moving through the pipe. Examples of such resistors include a cylindrical or streamer-shaped resistor attached to the outer circumferential surface of the moving body, a resistor made of multiple tapes attached to the outer circumferential surface of the moving body, and a feather- or bowl-shaped resistor attached to the outer end surface of the moving body.

[0027] The surface roughness of the moving body for increasing the fluid resistance is not limited to a numerical value, and it is sufficient that the fluid resistance at the end with the increased roughness is greater than the fluid resistance at the end with the decreased roughness. For example, the surface at the front end of the moving body may be mirror-finished, and the surface at the rear end may be matte-finished.

[0028] Next, an embodiment of a moving body according to the present invention will be described with reference to the drawings.

[0029] 2, the mobile object 1 is configured to move together with the liquid 3 in the inside of the pipeline 2 in which the leaking part 2a exists in the direction of the arrow, and to collect and record the sound generated at the leaking part 2a and transmitted through the liquid 3. After the mobile object 1 is removed from the pipeline 2, it is possible to detect the leak position in the pipeline 2 based on the recorded sound data and time, and the position data of the mobile object 1.

[0030] The moving body 1 is made of a metal such as aluminum or plastic, and has a cylindrical main body 1a, a cap 1b that has a hemispherical outer circumferential surface and is disposed at the front end of the main body 1a, and a cap 1c that is disposed at the rear end. Each of the caps 1b and 1c is attached to the main body 1a via a packing (not shown), thereby forming an accommodation space 1d inside for accommodating functional parts necessary for detecting leaks in a pipeline.

[0031] Two sets of sound recording members 5 are disposed in the housing space 1d formed in the moving body 1. That is, microphones 5a, 5a constituting the sound recording member 5 and recorders 5b, 5b for recording collected sounds are disposed at the front and rear of the moving body 1. In particular, one of the microphones 5a is disposed at the end on the downstream side in the moving direction of the moving body 1, and has directivity toward the downstream side. Meanwhile, the other microphone 5a is disposed at the end on the upstream side of the moving body 1, and has directivity toward the upstream side.

[0032] A clock 6 is disposed in a housing space main body 1d formed in the moving body 1, and collected sounds are recorded in accordance with the time measured by the clock 6.

[0033] Also disposed in the accommodation space 1d are a gyro sensor 7a for detecting the position of the moving object 1, and a recording member 7b for recording a signal generated by the gyro sensor 7a together with the time measured by the clock 6. Also disposed in the accommodation space 1d are a control unit 8 and a power source 9 for controlling the above-mentioned microphone 5a, recorder 5b, gyro sensor 7a, and recording member 7b.

[0034] As described above, when detecting the presence or absence of a leak in a target pipeline and its location, a mobile object is inserted and launched from a detection start point set in the pipeline, the launch time is recorded on the ground, and when it reaches the detection end point, it is removed and the arrival and removal times are recorded on the ground. Then, by analyzing the launch time, arrival time, recorded sound, the time when the sound was recorded, and the position of the mobile object corresponding to these times, the presence or absence of a leak in the target pipeline and its location are detected. For this reason, the clock that keeps time on the ground and clock 6 are configured to keep time in sync.

[0035] The configuration of the recorder 5b and the recording member 7b is not limited, but it is preferable that they are small and easy to handle. In this embodiment, a recording medium such as an SD card and a recording member that uses this recording medium are used.

[0036] A resistor 11 is attached to the outer peripheral surface of the rear end side (cap 1c side) of a main body 1a constituting the movable body 1. This resistor 11 is formed with an attachment part 11a having an inner diameter substantially equal to the outer diameter of the main body 1a, and a plurality of rectangular pieces 11b formed on the upstream side of the attachment part 11a in the flow direction of the liquid 3. The plurality of rectangular pieces 11b are arranged in a streamer shape from the cap 1c side of the main body 1a toward the upstream side in the flow direction of the liquid 3.

[0037] The material of resistor 11 is not particularly limited, but is preferably soft and cloth-like. In this way, resistor 11 made of soft cloth can be smoothly removed without strip 11b getting caught in a net, even when a net is used to remove movable body 1 from pipeline 2. In addition, the length of resistor 11 is not particularly limited, but it is preferable that the free end of strip 11b protrudes slightly beyond the end of cap 1c.

[0038] In particular, resistor 11 must be lightweight enough not to affect the specific gravity of movable body 1 relative to liquid 3 when attached to main body 1a of movable body 1. Also, strip 11b does not need to be formed along the entire circumference of cylindrical attachment portion 11a, and even if it is only about 1 / 2 the circumference, it is possible for resistor 11 to function as such. Furthermore, the length of resistor 11 may be about 1 / 3 to 1 / 10 of the length of movable body 1.

[0039] 2, the moving body 1 configured as described above moves while maintaining its longitudinal direction approximately parallel to the longitudinal direction (central axis) of the pipeline 2. However, during the movement of the moving body 1, for example, when passing through a curved portion of the pipeline 2, a part of the moving body 1 may come into contact with the pipeline wall. When the moving body 1 comes into contact with the pipeline wall, the posture of the moving body 1 changes so that the longitudinal direction of the moving body 1 is inclined with respect to the central axis of the pipeline 2.

[0040] The moving body 1, whose attitude has changed, moves together with the liquid 3 in the direction of the arrow a, as shown in Fig. 3, but because the resistor 11 is attached to the rear end side, the fluid resistance at the rear end side is greater than the fluid resistance at the front end side. Therefore, a force acts on the moving body 1 to rotate the rear end side in the direction of the arrow b, depending on the speed difference between the moving body 1 and the liquid 3 and the difference between the fluid resistance at the front end side and the fluid resistance at the rear end side. As a result, the rear end side of the moving body 1 approaches the central axis side of the pipe 2, and the moving body 1 returns to a posture parallel to the central axis of the pipe 2. Thereafter, the moving body 1 continues to move together with the liquid 3 in the direction of the arrow a while maintaining this state, and the sound transmitted through the liquid 3 is recorded along with the time.

[0041] Next, we will explain another example of a resistor to be attached to the moving body 1. Fig. 4(a) is a diagram explaining the configuration of the resistor 12, which is configured by arranging multiple cloth-like rectangular pieces 12 on the rear end side of the moving body 1 and attaching them with attachment pieces 12a such as rubber rings or adhesive tape.

[0042] The resistor 13 in Fig. 2(b) is made of a hemispherical net, and is attached to the rear end of the moving body 1 so that when it moves inside the pipeline 2, it is able to allow the liquid 3 to pass through even if the liquid 3 flows in. The material of the net is preferably natural or synthetic fiber. The resistor 14 in Fig. 2(c) is made of multiple protruding pieces 14a, and the protruding pieces 14a are formed by wrapping adhesive tape around the outer circumferential surface of the rear end of the moving body 1 and pinching it at multiple points.

[0043] In any of the above resistors 12 to 14, when the attitude of the movable body 1 relative to the longitudinal direction of the pipeline changes, it is possible to return this changed attitude to its original state, as in the case of the resistor 11 described above.

[0044] In the present invention, the shape of the resistor is not limited, and it is sufficient if it can realize different fluid resistances at the front end side and the rear end side of the moving body 1. [Industrial Applicability]

[0045] The moving body of the present invention can be used as a pipeline for water or oil, so long as the pipeline is one through which pressurized liquid flows. [Explanation of symbols]

[0046] 1. Mobile 2 conduit 2a Leaking part 3 liquid 1a Main unit 1b, 1c Cap 1d Containment space 5 Sound recording material 5a Microphone 5b Recorder 6. Standard Clock 7a Gyro sensor 7b Recording material 8. Control Unit 9 Power supply 11~14 Resistor 11a Mounting part 11b Strip of paper 12a Mounting piece 14a Projection piece

Claims

1. A moving body having a specific gravity substantially equal to the specific gravity of a liquid under pressure flowing through a pipeline, formed in an elongated shape having a length dimension greater than a width dimension, and moving along a central axis of the pipeline together with the liquid flowing through the pipeline, A moving body, characterized in that a fluid resistance to a liquid at one end side in a longitudinal direction is different from a fluid resistance to a liquid at the other end side.

2. A moving body as described in claim 1, characterized in that a resistor for the liquid is arranged on the outer surface of either one of the longitudinal ends, so that the fluid resistance for the liquid on the end side where the resistor is arranged is different from the fluid resistance for the liquid on the end side where the resistor is not arranged.

3. A moving body as described in claim 1, characterized in that when the moving body formed in an elongated shape moves through a pipeline together with liquid, and an end portion that is to be located upstream and an end portion that is to be located downstream in the direction of movement of the moving body are set, the fluid resistance of the moving body to the liquid at the end portion upstream in the direction of movement is greater than the fluid resistance of the moving body to the liquid at the end portion downstream in the direction of movement.

4. A resistor for the liquid is disposed on an outer surface of the end portion of the elongated movable body on the upstream side in the direction of movement, and the resistor is A movable body as described in claim 2 or 3, characterized in that it is configured to have an attachment portion attached to an outer surface of the movable body, and a plurality of rectangular pieces formed from the attachment portion toward the upstream side in the direction of movement of the movable body.

5. A moving body as described in claim 1, characterized in that the outer peripheral surface at either end in the longitudinal direction has a different surface roughness, so that the fluid resistance to the liquid at the end with the greater surface roughness is different from the fluid resistance to the liquid at the end with the smaller surface roughness.

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