Buried pipe inspection device and buried pipe inspection method

Abstract

To provide a buried pipe inspection device and a buried pipe inspection method that are superior in workability.SOLUTION: A buried pipe inspection device 1 comprises a body 10, wheels 20 provided rotatably on two side faces of the body 10, facing outward in a width direction W, and a first magnetic sensor 50 provided on a first face 10a connecting the two side faces of the body 10 in the width direction W, wherein the first face 10a can be fixed at respective positions where it face in a first direction or a second direction orthogonal to the first direction, and the first magnetic sensor 50 is movable on the first face 10a such that a magnetic field measurement direction M is aligned with one of third and fourth mutually orthogonal directions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a buried pipe inspection device and a buried pipe inspection method. [Background technology]

[0002] Methods for detecting underground pipes using the magnetic field method have been known for some time. In these methods, the magnitude of the magnetic field is measured using a magnetic sensor. This detection method is used to investigate the magnitude of the signal current flowing through the buried pipe and the soil cover, as well as to determine the location of buried pipes and branch pipes and contact with underground structures (other buried objects, valve chests, etc.). Buried pipe inspections using this magnetic field method measure the three-axis components (X-axis component, Y-axis component, and Z-axis component) of the magnetic field magnitude. While there are magnetic sensors on the market that can measure the three-axis components of the magnetic field, there are few magnetic sensors that can measure the three-axis components of the magnetic field with high sensitivity, and they are also expensive. Therefore, considering cost and measurement accuracy, it is preferable to have one detection sensor (magnetic sensor) for each measurement axis.

[0003] For example, in Patent Document 1, the magnetic sensor unit is installed in the center of the front end of the vehicle body. This allows the magnetic field strength formed near the buried pipe to be effectively detected when the detection vehicle is operating. Furthermore, for example, Patent Document 2 discloses a method for measuring the buried depth of a metal pipe by pulling up a detection coil a predetermined distance directly above the buried metal object, measuring the electromotive force before and after pulling up the detection coil, and calculating the ratio between the electromotive forces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-075546 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-284386 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as mentioned above, it is preferable to provide one detection sensor (magnetic sensor) for each measurement axis in a buried pipe inspection device. Therefore, when multiple magnetic sensors are installed, they must be installed at a certain distance from each other to prevent interference. Conventionally, installing multiple magnetic sensors at a distance from each other has been problematic, resulting in a large device size. This increased device size can lead to problems such as difficulty in measurement when there are obstacles (trees, curbs, fences, guardrails, etc.) around the device that obstruct scanning (travel), and poor maneuverability due to poor handling. Furthermore, this increased device size also leads to increased weight, leaving room for improvement in terms of ease of use, storage, and transportability.

[0006] The present disclosure has been made in consideration of such problems, and aims to provide a buried pipe inspection device and buried pipe inspection method that are easy to use. [Means for solving the problem]

[0007] The buried pipe inspection device disclosed herein comprises a body, wheels rotatably mounted on two side surfaces of the body facing outward in the width direction W, and a first magnetic sensor mounted on a first surface of the body connecting the two side surfaces in the width direction W, wherein the first surface can be fixed at each position facing a first direction or a second direction perpendicular to the first direction, and the first magnetic sensor is movable on the first surface so that the magnetic field measurement direction faces a third direction or a fourth direction perpendicular to each other. Furthermore, the buried pipe inspection method of the present disclosure using the above-mentioned buried pipe inspection device includes an X-axis component measurement step of measuring the X-axis component of the magnetic field while the first surface is fixed in a position facing the first direction and the magnetic field measurement direction of the first magnetic sensor is fixed in a position facing the third direction; a Y-axis component measurement step of measuring the Y-axis component of the magnetic field while the first surface is fixed in a position facing the first direction and the magnetic field measurement direction of the first magnetic sensor is fixed in a position facing the fourth direction; and a Z-axis component measurement step of measuring the Z-axis component of the magnetic field while the first surface is fixed in a position facing the second direction and the magnetic field measurement direction of the first magnetic sensor is fixed in a position facing the third direction. [Effects of the Invention]

[0008] The present disclosure can provide a buried pipe inspection device and a buried pipe inspection method that are easy to use. [Brief explanation of the drawings]

[0009] [Figure 1] 2 is a side view of the buried pipe inspection device in the first measurement state in this embodiment. FIG. [Figure 2] 2 is a view of the buried pipe inspection device (FIG. 1) in a first measurement state in this embodiment, seen from the direction of the arrow A, showing a cross section of the body. [Figure 3] 3 is a view of the buried pipe inspection device (FIG. 1) in a first measurement state in this embodiment, viewed in the direction of the arrow B. FIG. [Figure 4] FIG. 2 is a plan view of a first magnetic sensor in the present embodiment. [Figure 5] 3 is a schematic diagram showing a state in which a first magnetic sensor is attached to a first magnetic sensor support portion of a body in this embodiment. FIG. [Figure 6] FIG. 4 is a side view of a second magnetic sensor support portion of the embodiment. [Figure 7] 10 is a side view of the buried pipe inspection device in the second measurement state in this embodiment. FIG. [Figure 8] FIG. 8 is a view taken in the direction of the arrow B in FIG. 1 or FIG. 7 during the step of measuring each component. DETAILED DESCRIPTION OF THE INVENTION

[0010] In a conventional buried pipe inspection, an inspector applies an AC voltage between the buried pipeline to be inspected and a counter electrode, causing an AC current to flow. When AC current flows through a buried pipeline, a magnetic field is generated around the pipeline. Therefore, the inspector runs a buried pipe inspection device that uses a magnetic sensor to measure the magnetic field directly above the pipe in the inspection section. This is how the buried pipe inspection is carried out. The buried pipe inspection device and buried pipe inspection method disclosed herein relate to a device that uses a magnetic field method to detect underground buried pipes, and a method for detecting underground buried pipes using the device.

[0011] Hereinafter, embodiments of a buried pipe inspection device 1 and a buried pipe inspection method according to the present disclosure will be described with reference to the drawings.

[0012] FIG. 1 shows a side view of the buried pipe inspection device 1 in the first measurement state. In this embodiment, as shown in FIG. 1, a state in which the first sub-wheel 40a and the second sub-wheel 40b are in contact with the ground G is defined as a first measurement state, and as shown in FIG. 7, a state in which the second sub-wheel 40b and the third sub-wheel 40c are in contact with the ground G is defined as a second measurement state.

[0013] As shown in Figure 1, the buried pipe inspection device 1 in this embodiment comprises a body 10, wheels 20 rotatably mounted on two side surfaces of the body 10 facing outward in the width direction W, a first magnetic sensor 50 mounted on a first surface 10a connecting the two side surfaces of the body 10 in the width direction W, and a shaft 60 extending from a second surface 10b connecting the two side surfaces of the body 10 in the width direction W. The configuration of the buried pipe inspection device 1 will be described below using the buried pipe inspection device 1 in the first measurement state as an example.

[0014] Fig. 2 shows a view taken in the direction of arrow A in Fig. 1. Fig. 3 shows a view taken in the direction of arrow B in Fig. 1. As shown in Figures 2 and 3, in this embodiment, the body 10 has a container portion 11 having a rectangular parallelepiped shape, a rotary encoder 12 housed inside the container portion 11, a first magnetic sensor support portion 13 provided on a first surface 10a of the container portion 11, and a second magnetic sensor support portion holder 11a provided on a second surface 10b of the container portion 11. Hereinafter, of the six faces of the container 11 having a rectangular parallelepiped shape, the two side faces facing outward in the width direction W will be referred to as the side faces of the container 11 (body 10). Furthermore, of the four faces connecting the two side faces in the width direction W, the two faces that are horizontal to the ground G in a first measurement state described below will be referred to as first faces 10a of the container 11 (body 10), and the two faces that are perpendicular to the ground G in the first measurement state described below will be referred to as second faces 10b of the container 11 (body 10).

[0015] In this embodiment, the first magnetic sensor support part 13 is provided on the surface (lower surface) of the first surface 10a of the container part 11 that corresponds to the lower side of the container part 11 in the first measurement state. Note that the first magnetic sensor support part 13 may also be provided on the surface (upper surface) of the first surface 10a of the container part 11 that corresponds to the upper side of the container part 11 in the first measurement state. Note that, since the magnetic field is stronger closer to the buried pipe, it is preferable to provide the first magnetic sensor at a position close to the buried pipe. For this reason, it is preferable to provide the first magnetic sensor support part 13 on the surface (lower surface) that corresponds to the lower side of the container part 11 in the first measurement state.

[0016] Hereinafter, the first surface 10a refers to the surface (lower surface) that contacts the lower side of the container 11 in the first measurement state. The first magnetic sensor support 13 includes a plate-shaped first magnetic sensor support main body 13d and multiple pins (fulcrum pin 13a, first positioning pin 13b, and second positioning pin 13c). Specifically, in the first magnetic sensor support 13, the multiple pins fix the first magnetic sensor support main body 13d to the first surface 10a of the container 11 in a state where the first magnetic sensor support main body 13d faces the first surface 10a of the container 11. Note that, in this embodiment, for example, the first positioning pin 13b and the second positioning pin 13c have spacers 14. The spacer 14 has a cylindrical shape with an inner diameter larger than the diameters of the first positioning pin 13b and the second positioning pin 13c, and is fixed between the first surface 10a of the container 11 and the first magnetic sensor support main body 13d with the first positioning pin 13b or the second positioning pin 13c inserted therethrough. This forms a certain gap between the first surface 10a of the container 11 and the first magnetic sensor support main body 13d, and a first magnetic sensor 50, described below, can be accommodated in this gap. Note that the gap between the first surface 10a of the container 11 and the first magnetic sensor support main body 13d only needs to be large enough to accommodate the first magnetic sensor 50, described below, and is not limited to a configuration having the spacer 14.

[0017] In this embodiment, a second magnetic sensor support holder 11a is provided on the second surface 10b of the container 11. A second magnetic sensor support 80 (described in detail later) having a second magnetic sensor 81 is detachably fixed to the second magnetic sensor support holder 11a. The second magnetic sensor support 80 is fixed to the second magnetic sensor support holder 11a by inserting a second magnetic sensor support holder inserting portion 84 (see FIG. 6) of the second magnetic sensor support 80 into the second magnetic sensor support holder 11a. The second magnetic sensor support holder 11a may have any shape as long as it is engaged with the second magnetic sensor support holder inserting portion 84 and can maintain the second magnetic sensor support 80 perpendicular to the ground G in the first measurement state. For example, in this embodiment, the second magnetic sensor support holder inserting portion 84 has a circular cross-sectional shape, and therefore the second magnetic sensor support holder 11a having a circular hole in cross-sectional view is provided. It should be noted that if the second magnetic sensor support part 80 is not attached, the second magnetic sensor support part holder 11a may not be provided. Furthermore, a holder for fixing the second magnetic sensor support part 80 to the body 10 may be provided on the second magnetic sensor support part 80 side.

[0018] The wheels 20 are rotatably mounted on two side surfaces of the body 10 facing outward in the width direction W. In this embodiment, the wheels 20 include one main wheel 30 on one of the two side surfaces of the body 10 facing outward in the width direction W, and three sub-wheels 40 (first sub-wheel 40a, second sub-wheel 40b, and third sub-wheel 40c) on the other side of the body 10, which are arranged around the rotation axis of the main wheel 30. The main wheel 30 is placed on the ground G regardless of whether the first measurement state or the second measurement state is in the first or second measurement state. The rotation axis of the main wheel 30 is connected to the rotation axis of a rotary encoder 12 inside the body 10 via a coupling, gear, belt, or the like, thereby transmitting the rotation of the main wheel 30 to the rotary encoder 12, and the rotary encoder 12 can thereby measure the rotation speed of the main wheel 30. By measuring the rotation speed of the main wheel 30 with the rotary encoder 12, for example, the travel distance of the buried pipe inspection device 1 can be calculated. The three secondary wheels 40 have the same shape and size, and are connected to the body 10 via secondary wheel holders 41. The secondary wheel holders 41 are plate-like members that are square in plan view, and the three secondary wheels 40 are rotatably connected by secondary wheel shafts 42. Furthermore, the secondary wheel holders 41 themselves are fixed to the body 10. During measurement, contact with the ground G is ensured by a combination of the main wheel 30, the first auxiliary wheel 40a, and the second auxiliary wheel 40b (first measurement state), or a combination of the main wheel 30, the second auxiliary wheel 40b, and the third auxiliary wheel 40c (second measurement state). In this case, the radius L1 of the main wheel 30 and the vertical length L2 from the tangent line between the two points where the two secondary wheels 40 touch the ground to the central axis O (the rotation axis of the secondary wheel holder 41) of the main wheel 30 are the same. This ensures that two of the four faces connecting the two side faces of the rectangular parallelepiped body 10 in the width direction W are level with the ground G. The first measurement state and the second measurement state can be switched depending on whether the combination of secondary wheels 40 that touch the ground G is the first secondary wheel 40a and the second secondary wheel 40b, or the second secondary wheel 40b and the third secondary wheel 40c.

[0019] 4 is a schematic diagram of the first magnetic sensor 50. There are no particular limitations on the type of sensor used as the first magnetic sensor 50, and for example, a coil or a Hall element may be used.

[0020] 4, the first magnetic sensor 50 has a main body 52 and a sensor container 51. In this embodiment, the sensor container 51 and the main body 52 have a rectangular shape in a plan view. The main body 52 is disposed in a recess of the sensor container 51 so that the longitudinal directions of the sensor container 51 and the main body 52 are parallel. In this embodiment, the longitudinal direction of the main body 52 is the magnetic field measurement direction.

[0021] The sensor container 51 is provided with a hole 53 through which the aforementioned fulcrum pin 13a can be inserted. In this embodiment, the fulcrum pin 13a is inserted into the hole 53 of the first magnetic sensor 50, and the first magnetic sensor 50 is disposed so as to be sandwiched between the first magnetic sensor support body 13d and the first surface 10a of the container part 11. In this manner, the first magnetic sensor 50 is fixed to the first magnetic sensor support part 13.

[0022] FIG. 5 is a schematic diagram showing a state in which the first magnetic sensor 50 is attached to the first magnetic sensor support portion 13 of the body 10. As shown in FIG. As shown in FIG. 5, the first magnetic sensor 50 can move on the first surface 10a around the fulcrum pin 13a so that the magnetic field measurement direction M faces the third direction D3 or the fourth direction D4. Here, the third direction D3 and the fourth direction D4 indicate the orientations with respect to the first surface 10a of the body 10. The third direction D3 and the fourth direction D4 are both parallel to the first surface 10a and perpendicular to each other. The fourth direction D4 is parallel to the width direction W of the body 10. In this embodiment, two pins (the first positioning pin 13b and the second positioning pin 13c) that do not penetrate the first magnetic sensor 50 restrict the movement of the first magnetic sensor 50 so that the magnetic field measurement direction M of the first magnetic sensor 50 maintains a predetermined orientation (the third direction D3 or the fourth direction D4). 5(a), when the magnetic field measurement direction M of the first magnetic sensor 50 is moved along the third direction D3, a part of the short side of the first magnetic sensor 50 comes into contact with the first positioning pin 13b, thereby reliably fixing the first magnetic sensor 50 at a position where the magnetic field measurement direction M of the first magnetic sensor 50 faces the third direction D3. Also, when the magnetic field measurement direction M of the first magnetic sensor 50 is moved along the fourth direction D4, a part of the long side of the first magnetic sensor 50 comes into contact with the second positioning pin 13c, thereby reliably fixing the first magnetic sensor 50 at a position where the magnetic field measurement direction M of the first magnetic sensor 50 faces the fourth direction D4.

[0023] 1, 2, and 3, in this embodiment, the shaft 60 is connected to one of the two second surfaces 10b of the body 10, the same surface having the second magnetic sensor support holder 11a. As shown in FIGS. 2 and 3, a shaft holder 64 is connected to the body 10. Two shaft holders 64 are provided with a gap between them. A penetrating member 65 penetrates the shaft 60 perpendicularly to the longitudinal direction thereof, through the shaft holder 64, the lower end of the shaft 60, and the shaft holder 64 in that order. This allows the shaft 60 to be rotatable relative to the body 10 around the penetrating member 65 as an axis. The penetrating member 65 is parallel to the rotation axis O, and the shaft 60 is rotatable around an axis parallel to the rotation axis O.

[0024] In this embodiment, the shaft 60 is constructed by connecting multiple tubular members of different diameters. Specifically, it is composed of a large-diameter tubular member 61, a medium-diameter tubular member 62, and a small-diameter tubular member 63. For example, during storage or transportation, the small-diameter tubular member can be stored inside the large-diameter tubular member. This reduces the space required for storage and transportation. The configuration of the shaft 60 is not limited to the above. The shaft 60 may be made of one rod-shaped member, two rod-shaped members, or four or more rod-shaped members.

[0025] The buried pipe inspection device 1 only needs to have a mechanism capable of controlling its travel, and the structure of the connection between the shaft 60 and the body 10 is not limited to the above. In addition, the buried pipe inspection device 1 does not need to have the shaft 60.

[0026] In this embodiment, the buried pipe inspection device 1 has a changeover switch 70. The changeover switch 70 may be, for example, a two-pole, three-throw manual toggle switch. The changeover switch 70 is provided, for example, at the top of the shaft 60. The changeover switch 70 is provided, for example, axially below the handle of the shaft 60. The function of the changeover switch 70 will be described later.

[0027] Furthermore, in the buried pipe inspection device 1 of this embodiment, the second magnetic sensor support part 80 equipped with the second magnetic sensor 81 is detachable. FIG. 6 shows a side view of the second magnetic sensor support portion 80. As shown in FIG. As shown in FIG. 6, the second magnetic sensor support part 80 has a rod-shaped part 82. A second magnetic sensor 81 is disposed at the tip of the rod-shaped part 82 via the second magnetic sensor support part 80. Note that the tip of the rod-shaped part 82 here does not necessarily have to be the edge of the rod-shaped part 82 in the strict sense. The second magnetic sensor 81 is a magnetic sensor similar to the first magnetic sensor 50 shown in FIG. 4. A second magnetic sensor support part holder insertion part 84 is provided at the lower end of the rod-shaped part 82. Note that the second magnetic sensor support part 80 can be moved so that the magnetic field measurement direction M of the second magnetic sensor 81 faces the third direction D3 or the fourth direction D4.

[0028] The second magnetic sensor support part 80 having the second magnetic sensor 81 is provided to measure the soil covering of the buried pipe (details will be described later). When attaching the second magnetic sensor support part 80 to the body 10, the second magnetic sensor support part holder insertion part 84 is inserted into the second magnetic sensor support part holder 11a provided on the second surface 10b of the container part 11. This positions the rod-shaped part 82 perpendicular to the ground G, and the second magnetic sensor 81 can be provided at a certain distance vertically above the first magnetic sensor 50. The length of the rod-shaped portion 82 is not limited as long as it maintains a certain distance between the first magnetic sensor 50 and the second magnetic sensor 81 when the second magnetic sensor support portion 80 is attached to the body 10, but is preferably, for example, a length that maintains a distance of 50 cm between the first magnetic sensor 50 and the second magnetic sensor 81. A rod-shaped portion having a length that maintains a distance of 50 cm between the first magnetic sensor 50 and the second magnetic sensor 81 is preferable because it ensures sufficient accuracy in the soil cover measurement described below and is easy to handle.

[0029] Next, a buried pipe inspection method using the buried pipe inspection device 1 will be described. In a buried pipe inspection, an inspector applies an AC voltage between the buried pipeline to be inspected and a counter electrode, causing an AC current to flow. When AC current flows through a buried pipeline, a magnetic field is generated around the pipeline. Therefore, the inspector runs a buried pipe inspection device that uses a magnetic sensor to measure the magnetic field directly above the pipe in the inspection section. This is how the buried pipe inspection is carried out. A first cable 101 extending from the first magnetic sensor 50 is connected to a signal processing device (not shown). When the second magnetic sensor support part 80 (second magnetic sensor 81) is attached, a second cable 102 extending from the second magnetic sensor 81 is also connected to the signal processing device.

[0030] The buried pipe inspection method includes a magnetic field X-axis component measurement step, a magnetic field Y-axis component measurement step, a magnetic field Z-axis component measurement step, and an earth covering measurement step. Note that the present disclosure is not limited to a form including all of these steps. For example, the buried pipe inspection method does not need to include the earth covering measurement step. Hereinafter, the X-axis is defined as the direction of travel of the buried pipe inspection device 1, the Y-axis is defined as the direction horizontal and perpendicular to the direction of travel, and the Z-axis is defined as the vertical direction.

[0031] Fig. 7 shows the buried pipe inspection device 1 in the second measurement state. Fig. 8 shows a view taken in the direction of the arrow B in Fig. 1 or Fig. 7 in the process of measuring each directional component of the magnetic field. As shown in FIG. 1, in the first measurement state, the first surface 10a faces the first direction D1. Note that in the first measurement state, the third direction D3 is perpendicular to the first direction D1 and faces in the opposite direction to the second direction D2. As shown in FIG. 7, in the second measurement state, the first surface 10a faces the second direction D2. Note that in the second measurement state, the third direction D3 faces the same direction as the first direction D1. Regardless of whether the measurement state is the first or second measurement state, the fourth direction D4 is the same direction as the width direction W.

[0032] FIG. 8(a) shows a view of the buried pipe inspection device 1 in the direction of arrow B in the X-axis measurement process of the magnetic field. In the X-axis component measurement step, the first surface 10a is fixed in a position facing the first direction D1 (first measurement state), and the X-axis component of the magnetic field is measured with the magnetic field measurement direction M of the first magnetic sensor 50 fixed in a position facing the third direction D3 as shown in Fig. 5(a). By setting it in this state, the first surface 10a faces the first direction D1 and the third direction D3 faces opposite to the second direction D2, so that the magnetic field measurement direction M of the first magnetic sensor 50 can be aligned with the X-axis, which is the depth direction of the paper, as shown in Fig. 8(a), and the X-axis component of the magnetic field can be measured.

[0033] FIG. 8(b) shows a view of the buried pipe inspection device 1 in the direction of the arrow B in the Y-axis measurement process of the magnetic field. In the Y-axis component measurement step, the first surface 10a is fixed in a position facing the first direction D1 (first measurement state), and the Y-axis component of the magnetic field is measured with the magnetic field measurement direction M of the first magnetic sensor 50 fixed in a position facing the fourth direction D4 as shown in Fig. 5(b). By setting it in this state, the first surface 10a faces the first direction D1 and the fourth direction D4 is along the width direction W, so that the magnetic field measurement direction M of the first magnetic sensor 50 can be aligned with the Y-axis, which is the left-right direction on the paper, as shown in Fig. 8(b), and the Y-axis component of the magnetic field can be measured.

[0034] FIG. 8(c) shows a view of the buried pipe inspection device 1 in the direction of arrow B during the Z-axis measurement process of the magnetic field. In the Z-axis component measurement step, the first surface 10a is fixed in a position facing the second direction D2 (set to a second measurement state), and the Z-axis component of the magnetic field is measured with the magnetic field measurement direction M of the first magnetic sensor 50 fixed in a position facing the third direction D3 as shown in Fig. 5(a). By setting it in this state, the first surface 10a faces the second direction D2 and the third direction D3 faces the first direction D1, so that the magnetic field measurement direction M of the first magnetic sensor 50 can be aligned with the Z-axis, which is the vertical direction of the paper, as shown in Fig. 8(c), and the Z-axis component of the magnetic field can be measured.

[0035] In the earth cover measurement process, with the buried pipe inspection device 1 in the first measurement state, the second magnetic sensor support part 80 is attached to the body 10, and the earth cover is measured using the first magnetic sensor 50 and the second magnetic sensor 81. The soil covering measurement step includes at least one of an X-axis soil covering measurement step and a Y-axis soil covering measurement step. In the X-axis soil cover measurement process, the first surface 10a is fixed in a position parallel to the ground G, and the magnetic field measurement direction M of the first magnetic sensor 50 and the second magnetic sensor 81 is fixed in a position facing the third direction D3. With this fixed position, the X-axis component of the magnetic field is measured by the first magnetic sensor 50 and the second magnetic sensor 81, and the soil cover is calculated from each measurement value and the distance between the first magnetic sensor 50 and the second magnetic sensor 81. In the Y-axis soil cover measurement process, the first surface 10a is fixed in a position parallel to the ground G, and the magnetic field measurement direction M of the first magnetic sensor 50 and the second magnetic sensor 81 is fixed in a position facing the fourth direction D4.The Y-axis component of the magnetic field is measured by the first magnetic sensor 50 and the second magnetic sensor 81, and the soil cover is calculated from each measurement value and the distance between the first magnetic sensor 50 and the second magnetic sensor 81. The soil cover is calculated by a known method using the value of the X-axis component or Y-axis component of the measured magnetic field.

[0036] In each of the above steps, the signals from the magnetic sensors are processed by a two-channel signal processing device. Therefore, by using a two-pole, three-throw changeover switch 70, the magnetic sensors input to each channel can be switched. Specifically, for example, if input 1 is when the switch is flipped to one side, input 2 is when it is flipped to the other side, and input 3 is when the switch is in the center, the magnetic sensors input to each channel can be switched as follows:

[0037] When input is made to input 1, the signal from the first magnetic sensor 50 is input to both channels of the signal processing device. Such input 1 is used, for example, when it is desired to simultaneously measure two different frequency components of the magnetic field detected by the first magnetic sensor.

[0038] When input is made to input 2, the signal from the second magnetic sensor 81 is input to both channels of the signal processing device. For example, this is used when you want to simultaneously measure two different frequency components of the magnetic field detected by the second magnetic sensor 81.

[0039] When input 3 is input, the signal from the first magnetic sensor 50 is input to channel 1 of the signal processing device, and the signal from the second magnetic sensor 81 is input to channel 2. This type of input 3 is used, for example, when it is desired to measure the signals from the first magnetic sensor 50 and the second magnetic sensor 81 simultaneously. Note that, since signals from two magnetic sensors can be measured at once, it is preferable to perform soil cover measurement in this state.

[0040] The signals measured as described above are processed by a signal processing device connected to the cable and then recorded on a recorder. The signal processing device connected to the cable may be, for example, a signal processing device installed in Super Codings (registered trademark).

[0041] As described above, the buried pipe inspection device 1 of the present disclosure comprises a body 10, wheels 20 rotatably mounted on two side surfaces of the body 10 facing outward in the width direction W, and a first magnetic sensor 50 mounted on a first surface 10a connecting the two side surfaces of the body 10 in the width direction W, the first surface 10a being capable of being fixed at each position facing a first direction D1 or a second direction D2 perpendicular to the first direction D1, and the first magnetic sensor 50 being movable on the first surface 10a so that the magnetic field measurement direction M faces a third direction D3 or a fourth direction D4 perpendicular to each other. With this configuration, the first surface 10a can be fixed in a position parallel to or perpendicular to the ground G. By moving the first magnetic sensor 50 so that its magnetic field measurement direction M faces the second direction D2 or the first direction D1, the magnetic field measurement direction M of the magnetic sensor can be positioned along each of the X-axis, Y-axis, and Z-axis. This allows a single magnetic sensor to measure three-axis components of the magnetic field. Compared to conventional devices that require a magnetic sensor corresponding to each axial component, the device size can be reduced, as can the number of required magnetic sensors and the size of components. This reduces the material cost of the device. Furthermore, by reducing the device size, a navigable range can be ensured even when there are obstacles (such as trees, curbs, fences, and guardrails) around the device that obstruct scanning (travel). This allows for an inexpensive and easy-to-use buried pipe inspection device 1.

[0042] The wheel 20 may also include a main wheel 30 provided on one of the two side surfaces and a plurality of secondary wheels 40 provided on the other of the two side surfaces and arranged around the rotation axis of the main wheel 30, and the secondary wheels 40 may have a first secondary wheel 40a, a second secondary wheel 40b, and a third secondary wheel 40c, and the first surface 10a may be fixed in a position facing the first direction D1 when the first secondary wheel 40a and the second secondary wheel 40b contact the ground G, and the first surface 10a may be fixed in a position facing the second direction D2 when the second secondary wheel 40b and the third secondary wheel 40c contact the ground G. With this configuration, by changing the combination of the three sub-wheels 40 that contact the ground G, the magnetic field measurement direction M of the first magnetic sensor 50 can be fixed at a position along each of the three axes. Specifically, for example, by fixing the first magnetic sensor 50 in a position (the state shown in FIG. 5( a)) where the magnetic field measurement direction M of the first magnetic sensor 50 faces the third direction D3 with the first sub-wheel 40a and the second sub-wheel 40b in contact with the ground G (a state where the first surface 10a is fixed in a position parallel to the ground G), the magnetic field measurement direction M of the first magnetic sensor 50 can be oriented in the second direction D2, and the X-axis component of the magnetic field can be measured. From this state, by changing the wheels 20 in contact to the second sub-wheel 40b and the third sub-wheel 40c and rotating the body 10 90 degrees in the axial direction, the magnetic field measurement direction M of the first magnetic sensor 50 can be oriented in the first direction D1. That is, when the magnetic field measurement direction M of the first magnetic sensor 50 is aligned vertically, the Z-axis component of the magnetic field can be measured. Furthermore, with the above configuration, a total of three ground contact points are ensured: one point where the main wheel 30 is grounded and one point where each of the two sub-wheels 40 is grounded. With these three ground contact points, the orientation of the first surface 10a can be maintained horizontally or vertically relative to the ground G. This allows the three-axis components of the magnetic field to be measured stably without requiring a complex mechanism. Therefore, the buried pipe inspection device 1 can be made inexpensive and easy to use.

[0043] The electronic device may further include a rod-shaped portion 82 extending from the body 10 to the side opposite the first surface 10a, and a second magnetic sensor 81 disposed at the tip of the rod-shaped portion 82. With this configuration, the first magnetic sensor 50 and the second magnetic sensor 81 are provided at a fixed distance vertically above the first magnetic sensor 50. This makes it possible to measure the soil covering of the buried pipe.

[0044] The buried pipe inspection method of the present disclosure is a buried pipe inspection method using the above-mentioned buried pipe inspection device 1, and includes an X-axis component measurement process for measuring the X-axis component of the magnetic field while fixing the first surface 10a in a position facing the first direction D1 and the magnetic field measurement direction M of the first magnetic sensor 50 in a position facing the third direction D3; a Y-axis component measurement process for measuring the Y-axis component of the magnetic field while fixing the first surface 10a in a position facing the first direction D1 and the magnetic field measurement direction M of the first magnetic sensor 50 in a position facing the fourth direction D4; and a Z-axis component measurement process for measuring the Z-axis component of the magnetic field while fixing the first surface 10a in a position facing the second direction D2 and the magnetic field measurement direction M of the first magnetic sensor 50 in a position facing the third direction D3. With this configuration, by changing the orientation of the magnetic field measurement direction M of one magnetic sensor for each process, the magnetic field measurement direction M of the magnetic sensor can be arranged so that it is aligned with each of the X-axis, Y-axis, and Z-axis. By including the above process, it becomes possible to measure three-axis components of the magnetic field with one magnetic sensor. As a result, the values ​​of the measured three-axis components of the magnetic field can be used to measure the position of the buried pipe and investigate contact with underground structures using known methods. This makes it possible to provide a buried pipe inspection method with excellent workability.

[0045] The method may further include a soil covering measurement step of measuring soil covering.

[0046] The soil cover measurement process may include at least one of an X-axis soil cover measurement process in which the first surface 10a is fixed in a position facing the first direction D1 and the magnetic field measurement direction M of the first magnetic sensor 50 and the second magnetic sensor 81 is fixed in a position facing the third direction D3, and the soil cover is measured while the first surface 10a is fixed in a position facing the first direction D1 and the magnetic field measurement direction M of the first magnetic sensor 50 and the second magnetic sensor 81 is fixed in a position facing the fourth direction D4. With this configuration, each axis component of the magnetic field can be measured by the first magnetic sensor 50 and the second magnetic sensor 81, which is spaced a certain distance vertically above the first magnetic sensor 50. This makes it possible to measure the soil cover of the buried pipe. The soil cover is calculated by a known method using the value of the X-axis component or Y-axis component of the measured magnetic field. According to the above configuration, the first magnetic sensor 50 and the second magnetic sensor 81 can be shared in the X-axis soil covering measurement process and the Y-axis soil covering measurement process. Therefore, the X-axis soil covering measurement process and the Y-axis soil covering measurement process can be performed using only two magnetic sensors (the first magnetic sensor 50 and the second magnetic sensor 81). This makes it possible to provide a buried pipe inspection method with excellent workability.

[0047] One embodiment of the present disclosure has been described above in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and configuration changes, combinations, deletions, etc. are also included within the scope that does not deviate from the gist of the present disclosure.

[0048] For example, the buried pipe inspection device need only have a configuration that allows it to move while maintaining the direction in which the first surface of the body faces, and is not limited to a configuration having main wheels and sub wheels. [Explanation of symbols]

[0049] 1. Buried pipe inspection equipment 10 Body 10a 1st page 10b 2nd side 20 wheels 30 Main wheels 40 Secondary wheels 40a First auxiliary wheel 40b 2nd secondary wheel 40c 3rd secondary wheel 50 First magnetic sensor 81 Second magnetic sensor 82 Rod-shaped part G ground

Claims

1. Body and Wheels rotatably provided on two side surfaces of the body facing outward in the width direction; a first magnetic sensor provided on a first surface of the body that connects the two side surfaces in a width direction; Equipped with The first surface can be fixed at each position facing a first direction or a second direction perpendicular to the first direction, the first magnetic sensor is movable on the first surface so that a magnetic field measurement direction faces a third direction or a fourth direction that are orthogonal to each other; Buried pipe inspection equipment.

2. The wheel is a main wheel provided on one of the two sides; a plurality of secondary wheels provided on the other of the two side surfaces and arranged around the rotation axis of the main wheel; The auxiliary wheels include a first auxiliary wheel, a second auxiliary wheel, and a third auxiliary wheel, the first surface is fixed at a position facing the first direction by the first auxiliary wheel and the second auxiliary wheel contacting the ground, The first surface is fixed at a position facing the second direction by the second auxiliary wheel and the third auxiliary wheel contacting the ground. The buried pipe inspection device according to claim 1.

3. a rod-shaped portion extending from the body to a side opposite to the first surface; Further, a second magnetic sensor is provided at the tip of the rod-shaped portion. The buried pipe inspection device according to claim 1.

4. A buried pipe inspection method using the buried pipe inspection device according to claim 1, an X-axis component measurement step of measuring an X-axis component of a magnetic field while fixing the first surface at a position facing the first direction and fixing the magnetic field measurement direction of the first magnetic sensor at a position facing the third direction; a Y-axis component measurement step of measuring a Y-axis component of a magnetic field while fixing the first surface at a position facing the first direction and fixing the magnetic field measurement direction of the first magnetic sensor at a position facing the fourth direction; a Z-axis component measurement step of fixing the first surface at a position facing the second direction and measuring a Z-axis component of a magnetic field in a state where the magnetic field measurement direction of the first magnetic sensor is fixed at a position facing the third direction; Equipped with Buried pipe inspection method.

5. A buried pipe inspection method using the buried pipe inspection device according to claim 3, Further includes a soil covering measurement step of measuring soil covering. Buried pipe inspection method.

6. The soil covering measurement step includes: An X-axis soil covering measurement process in which the first surface is fixed in a position facing the first direction and the magnetic field measurement directions of the first magnetic sensor and the second magnetic sensor are fixed in a position facing the third direction, or The first surface is fixed in a position facing the first direction, and the magnetic field measurement directions of the first magnetic sensor and the second magnetic sensor are fixed in a position facing the fourth direction, and a Y-axis soil cover measurement process is included. The buried pipe inspection method according to claim 5.

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