How to inspect the inside of a chimney

Abstract

To provide a chimney internal inspection method capable of inspecting a state of an inner surface of a chimney with more high accuracy.SOLUTION: A chimney internal inspection method comprises: flying a flying object equipped with an optical sensor inside the chimney; measuring a distance to the inner peripheral surface of a chimney with the optical sensor while flying the flying object in a predetermined measurement target range of the inner peripheral surface; and based on the measurement result, generating a distribution map showing unevenness distribution in the measurement target range of the inner peripheral surface.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a chimney interior inspection method. [Background technology]

[0002] A technology is known in which an aircraft such as a drone flies inside the body of a chimney, moves up and down, and captures images of the inner surface using an imaging device, and then performs inspection based on the captured images (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6505927 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 makes it possible to inspect the appearance of the inner peripheral surface based on captured images. However, for example, the effects of corrosion of the lining material formed on the inner surface of the chimney barrel cannot be adequately inspected using images, and it is necessary to actually measure the thickness of the lining material. For this reason, there is a demand for a method that can detect the condition of the inner peripheral surface of a chimney with higher accuracy.

[0005] The present disclosure has been made in consideration of the above, and aims to provide a chimney interior inspection method that is capable of detecting the internal condition of a chimney with high accuracy. [Means for solving the problem]

[0006] The chimney interior inspection method according to the present disclosure involves flying an aircraft equipped with an optical sensor inside the chimney, measuring the distance to the inner surface of the chimney using the optical sensor while the aircraft is flying within a predetermined measurement range of the inner surface, and generating a distribution map showing the distribution of irregularities within the measurement range of the inner surface based on the measurement results. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a chimney interior inspection method that can detect the condition of the inner surface of the chimney barrel with higher accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of devices and equipment used in the chimney interior inspection method according to this embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a distribution map. [Figure 3] FIG. 3 is a cross-sectional view of the chimney shown in FIG. 1 taken along line AA. [Figure 4] FIG. 4 is a BB cross-sectional view of the chimney shown in FIG. [Figure 5] FIG. 5 is a CC cross-sectional view of the chimney shown in FIG. [Figure 6] FIG. 6 is a flowchart showing an example of a chimney interior inspection method according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of a chimney interior inspection method according to the present disclosure will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially identical.

[0010] Fig. 1 is a diagram showing an example of the configuration of devices and equipment used in the chimney interior inspection method according to this embodiment. In the chimney interior inspection method according to this embodiment, for example, a lining 102 applied to the inner surface 101 of a cylindrical chimney 100 is inspected for any abnormalities such as peeling, cracks, or foreign matter accumulation, and the extent of the abnormalities is photographed with a photographing device. As shown in Fig. 1, the chimney interior inspection method uses an aircraft 10 and a processing device 20.

[0011] The aircraft 10 is configured to be able to fly up and down in the air inside the chimney 100. For example, a drone or the like is used as the aircraft 10. The aircraft 10 has a main body 11, a propeller 12, and a propeller drive unit 13. The propeller 12 and the propeller drive unit 13 are provided on the main body 11. The propeller 12 is rotated by the propeller drive unit 13, allowing the aircraft 10 to move up and down inside the chimney 100. The aircraft 10 has a rotation detection sensor (not shown). The rotation detection sensor detects the orientation of the aircraft 10 in the horizontal direction.

[0012] In this embodiment, the flying vehicle 10 is configured to move horizontally and vertically, for example, according to the pilot's control, but may also be configured to be capable of autonomous flight. The flying vehicle 10 takes off and lands on a takeoff and landing platform 104 located at the bottom of the chimney 100. The takeoff and landing platform 104 is located on the central axis AX of the chimney 100. Therefore, the flying vehicle 10 takes off from a position on the central axis AX and lands at a position on the central axis AX.

[0013] The aircraft 10 is equipped with an optical sensor 30. The optical sensor 30 measures the distance to an object by irradiating light onto the object, which is located in a spherical shape around the optical sensor 30 and is located within a distance of several tens of meters, and detecting the light scattered by the object. The detectable range of the optical sensor 30 can be the range within a sphere centered on the optical sensor 30. The sphere is set to a range larger than the diameter of the inner circumferential surface 103, centered on the central axis AX. The optical sensor 30 can measure the distance to the object as three-dimensional data.

[0014] In this embodiment, the optical sensor 30 measures the distance to the inner circumferential surface 103 of the chimney 100. The inner circumferential surface 103 includes the surface 102a of the lining 102 and the exposed portion 101a where the inner surface 101 of the barrel is exposed. The optical sensor 30 measures the distance as three-dimensional data across the entire inner circumferential surface 103 included in the detectable range. If the inner circumferential surface 103 within the detectable range has concaves and convexes, the optical sensor 30 measures the distance to each of the concaves and convexities. In this embodiment, the optical sensor 30 measures three-dimensional data of the distance across a predetermined measurement range, for example, in the circumferential and height directions of the inner circumferential surface 103 of the chimney 100. The measurement range may be a portion or the entire inner circumferential and height directions of the inner circumferential surface 103.

[0015] By controlling the propeller drive unit 13 based on the measurement results of the optical sensor 30, the aircraft 10 can autonomously control its position and attitude inside the chimney 100 so as not to interfere with the inner surface 103.

[0016] A device such as a personal computer is used as the processing device 20. The processing device 20 has a processing device such as a CPU (Central Processing Unit) and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The processing device 20 acquires three-dimensional data measured by the optical sensor 30, and calculates the distribution of unevenness on the inner circumferential surface 103 within the measurement range based on the three-dimensional data.

[0017] After generating a distribution map of irregularities in the measurement range, the processing device 20 can calculate the thickness t of the lining 102 based on the distribution map. The processing device 20 calculates the position of the central axis AX of the chimney 100, and calculates the thickness t of the lining 102 as the difference obtained by subtracting a second distance R2, which is the distance between the central axis AX and the inner circumferential surface 103, from a first distance R1, which is the distance between the central axis AX and the barrel inner surface 101.

[0018] The processing device 20 can calculate the position of the central axis AX based on the detection result of the optical sensor 30 at the exposed portion 101a of the barrel inner surface 101. The processing device 20 can also calculate the position of the central axis AX by measuring the thickness t of the lining 102 at any target position on the inner circumferential surface 103 and comparing the measurement result with the detection result of the optical sensor 30 at the target position. In this embodiment, the exposed portion 101a includes, for example, at least one of the upper edge portion 101b along the top of the barrel inner surface 101 and the manhole formation portion 105 of the chimney 100.

[0019] Next, an example of a chimney interior inspection method according to this embodiment will be described. First, an aircraft 10 equipped with an optical sensor 30 is flown inside a chimney 100, and while the aircraft 10 is flying, the optical sensor 30 measures the distance to the inner circumferential surface 103 of the chimney 100 within a predetermined measurement range of the inner circumferential surface 103. Based on the measurement results, a distribution map showing the distribution of irregularities within the measurement range of the inner circumferential surface 103 is generated.

[0020] The detectable range of the optical sensor 30 in the aircraft 10 is a spherical range of several tens of meters or less centered on the optical sensor 30. When flying the aircraft 10, the pilot launches the aircraft 10 from a position on the central axis AX of the takeoff and landing pad 104. If there is an obstacle within the detection distance of the spherical detectable range centered on the aircraft 10, the pilot can fly the aircraft 10 while avoiding the obstacle. Therefore, the pilot only flies the aircraft 10 along the central axis AX. For example, if the aircraft 10 approaches the lining 102, the optical sensor 30 detects the lining 102 and the aircraft 10 flies to avoid the lining 102, automatically avoiding interference.

[0021] The pilot then raises the flying object 10 at a constant speed along the central axis AX. In this case, the optical sensor 30 acquires three-dimensional data of the inner circumferential surface 103 of the chimney 100 in the height direction.

[0022] The processing device 20 generates a distribution map of unevenness based on the three-dimensional data measured by the optical sensor 30. The processing device 20 can display the generated distribution map on a display unit (not shown) or the like.

[0023] Fig. 2 is a diagram showing an example of a distribution map. As shown in Fig. 2, a distribution map F of irregularities is formed based on three-dimensional data in the height direction and circumferential direction of the inner circumferential surface 103. For example, in the distribution map F in Fig. 2, a gradation from white to black is formed, with the closer to white the more convex the shape, and the closer to black the more concave the shape. The area F1 displayed in black in Fig. 2 is the part corresponding to the manhole formation portion 105 described above.

[0024] After generating the unevenness distribution map F, the processing device 20 can calculate the thickness of the lining 102 based on the distribution map F. Figures 3 to 5 are cross-sectional views of the chimney 100 shown in Figure 1. Figure 3 shows the structure along the AA cross section, Figure 4 shows the structure along the BB cross section, and Figure 5 shows the structure along the CC cross section, respectively.

[0025] 3 to 5, the processing device 20 calculates the position of the central axis AX of the chimney 100, and calculates the thickness of the lining 102 as the difference obtained by subtracting a second distance R2, which is the distance between the central axis AX and the inner circumferential surface 103, from a first distance R1, which is the distance between the central axis AX and the barrel inner surface 101. For the first distance R1, for example, the design value of the barrel inner surface 101 can be used.

[0026] Furthermore, the processing device 20 can calculate the position of the central axis AX by measuring the thickness of the lining 102 at any target position on the inner circumferential surface 103 and comparing the measurement result with the detection result of the optical sensor 30 at the target position. For example, by measuring the thickness of the lining 102 at a target position near the bottom of the chimney 100, which is close to the manhole formation portion 105 (see FIG. 3), it is possible to easily obtain the measured value.

[0027] The processing device 20 can also calculate the position of the central axis AX based on the detection results of the optical sensor 30 at the exposed portion 101a of the barrel inner surface 101. In this embodiment, the exposed portion 101a includes, for example, at least one of the portion along the top of the barrel inner surface 101 (see FIG. 5) and the manhole-forming portion 105 of the chimney 100 (see FIG. 3). At the height position shown in FIG. 4, the exposed portion 101a where the barrel inner surface 101 is exposed does not exist. Therefore, by including the exposed portion 101a in the optical sensor 30, the position of the central axis AX can be easily calculated. For example, it is sufficient to include a height position including the vicinity of the bottom of the chimney 100 as shown in FIG. 3, or a height position including the vicinity of the top of the chimney 100 as shown in FIG. 5. Furthermore, the position of the central axis AX can be calculated by matching the detection results of the optical sensor 30 at the barrel inner surface 101 with the detection results of the three-dimensional data of the barrel outer surface by bringing the optical sensor 30 outside the barrel and detecting three-dimensional data of the barrel outer surface at any point.

[0028] The result of detecting the exposed portion 101a by the optical sensor 30 corresponds to the height position of the barrel inner surface 101 in the distribution diagram F. The thickness of the lining 102 can be considered to be the relative height position between it and the exposed portion 101a. The processing device 20 calculates a value for the distribution of irregularities based on the position of the exposed portion 101a. This calculation result corresponds to the height position (thickness) relative to the exposed portion 101a. Therefore, the processing device 20 may calculate this calculation result as the thickness of the lining 102. Similarly, the processing device 20 may calculate a value for the distribution of irregularities over the entire measurement target range AR based on the actual measurement result at the target position, and calculate the thickness of the lining 102 based on the calculation result.

[0029] Fig. 6 is a flowchart showing an example of a chimney interior inspection method according to this embodiment. As shown in Fig. 6, first, a pilot controls the flying object 10 to fly inside the chimney 100 (step S10). While the flying object 10 is flying, the optical sensor 30 creates three-dimensional data based on the distance to the inner surface 103 of the chimney 100 (step S20). As the pilot flies the flying object 10 up to the height of the chimney, the optical sensor 30 creates three-dimensional data for the entire height of the chimney 100 (step S30).

[0030] The processing device 20 generates a distribution map F indicating the distribution of unevenness on the inner circumferential surface 103 based on the measurement results of the optical sensor 30 (step S40). After generating the distribution map F, the processing device 20 calculates the thickness of the lining 102 formed on the barrel inner surface 101 based on the distribution map (step S50).

[0031] As described above, the chimney interior inspection method according to this embodiment involves flying an aircraft 10 equipped with an optical sensor 30 inside the chimney 100, measuring the distance to the inner surface 103 of the chimney 100 using the optical sensor 30 while the aircraft 10 is flying, and generating a distribution diagram F showing the distribution of unevenness on the inner surface 103 based on the measurement results.

[0032] In this configuration, by generating a distribution map F of irregularities on the inner peripheral surface 103 of the chimney 100, it is possible to easily grasp recesses on the inner peripheral surface 103, i.e., thinned portions due to corrosion, etc. This makes it possible to inspect the condition of the inner peripheral surface of the chimney 100 with higher accuracy than when inspecting an image of the inner peripheral surface 103.

[0033] In the chimney interior inspection method according to this embodiment, the chimney 100 has a configuration in which a lining 102 is formed on a barrel inner surface 101, and the thickness of the lining 102 formed on the barrel inner surface 101 is calculated based on the generated distribution map F. Therefore, it is possible to detect the thickness of the lining 102 formed on the barrel inner surface 101 of the chimney 100 with high accuracy.

[0034] In the chimney interior inspection method according to this embodiment, the inner circumferential surface 103 includes a surface 102a of the lining 102 and an exposed portion 101a where the barrel inner surface 101 is exposed, and the position of the central axis AX of the chimney 100 is calculated, and the thickness of the lining 102 is calculated as the difference obtained by subtracting a second distance R2, which is the distance between the central axis AX and the inner circumferential surface 103, from a first distance R1, which is the distance between the central axis AX and the barrel inner surface 101. Therefore, the position of the central axis AX is calculated by taking advantage of the characteristics of the chimney 100 being a cylinder, and the thickness of the lining 102 can be calculated with high accuracy based on the calculated position of the central axis AX.

[0035] In the chimney interior inspection method according to this embodiment, the thickness of the lining 102 is measured at any target position on the inner circumferential surface 103, and the position of the central axis AX is calculated by comparing the actual measurement result with the detection result of the optical sensor 30 at the target position. Therefore, by providing the actual measurement value for the relative thickness position on the inner circumferential surface 103 of the chimney 100, the thickness of the lining 102 can be efficiently calculated based on the actual measurement value.

[0036] In the chimney interior inspection method according to this embodiment, the position of the central axis AX is calculated based on the detection result of the optical sensor 30 on the exposed portion 101a. The distance between the central axis AX and the exposed portion 101a corresponds to the first distance R1. Therefore, when the measurement range AR includes the exposed portion 101a, the position of the central axis AX can be easily calculated based on the detection result of the optical sensor 30 on the exposed portion 101a.

[0037] In the chimney interior inspection method according to this embodiment, the exposed portion 101a includes at least one of the portion along the top of the barrel inner surface 101 and the portion of the chimney 100 where a manhole is formed. Therefore, when the measurement range AR includes the portion along the top of the barrel inner surface 101 and the portion of the chimney 100 where a manhole is formed, the position of the central axis AX can be easily calculated based on the detection results of the optical sensor 30 in these portions.

[0038] In the chimney interior inspection method according to this embodiment, when flying the flying object 10, the attitude of the flying object 10 is autonomously controlled using the optical sensor 30. Therefore, stable measurements can be performed.

[0039] The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, an example configuration in which an imaging device such as a camera is not provided on the aircraft 10 has been described, but this is not limiting. For example, a configuration in which a camera is provided on the aircraft 10 may also be used. In this case, by performing measurements using the optical sensor 30 and capturing images using a camera while the aircraft 10 is flying, it becomes possible to perform inspections with even higher precision.

[0040] In the above embodiment, the chimney 100 is described as being installed so that the central axis AX is aligned vertically, but the present invention is not limited to this. The above description can also be applied to the chimney 100 when the central axis AX is inclined relative to the vertical.

[0041] In the above embodiment, the case where the flying object 10 performs autonomous control has been described as an example, but the present invention is not limited to this. For example, a guide rope may be provided on the chimney 100, and the flying object 10 may move up and down along the guide rope.

[0042] In the above embodiment, the lining 102 is formed inside the chimney 100, but the present invention is not limited to this. In a configuration where the chimney 100 does not have a lining and the inner surface 101 of the barrel is exposed, the present invention can also be applied to measuring the thickness of the steel plate that forms the inner surface 101 of the barrel when the steel plate is corroded and thinned. [Explanation of symbols]

[0043] 10 Flying Objects 11 Main body 12 propellers 13 Propeller drive unit 20 Processing equipment 30 Optical Sensor 100 Chimney 101 Inner surface of barrel 101a Exposed part 101b Upper edge 102 Lining 102a surface 103 Inner surface 104 Departure and Arrival Platform 105 Manhole formation part AR measurement range AX center axis F distribution plot F1 area R Detectable range R1 First distance R2 2nd distance

Claims

1. Flying a flying object equipped with an optical sensor and a camera inside the chimney, While flying the flying object, the optical sensor measures the distance to the inner circumferential surface of the chimney within a predetermined measurement range of the inner circumferential surface, and the camera captures an image of the inner circumferential surface of the chimney; generating a distribution map showing the distribution of irregularities in the measurement range of the inner circumferential surface based on the measurement results; The measurement target range is inspected using the distribution map and the image capture results by the camera, The optical sensor irradiates light in a spherical shape with the optical sensor as the center, and a range within a sphere having a diameter larger than a diameter of the inner circumferential surface and centered on the central axis of the chimney with the optical sensor as the center is set as a detectable range, When the flying object is flown, the flying object is caused to levitate on the central axis from a point on the central axis at the bottom of the chimney, and when an obstacle is detected within the detectable range of the flying object by the optical sensor, the attitude of the flying object is autonomously controlled so as to avoid the obstacle. How to inspect the inside of a chimney.

2. The chimney has a configuration in which a lining is formed on the inner surface of a cylindrical body, The thickness of the lining formed on the inner surface of the tube body is calculated based on the generated distribution map. The method for inspecting the inside of a chimney according to claim 1.

3. the inner circumferential surface includes an exposed portion where the surface of the lining and the inner surface of the cylindrical body are exposed, The inner surface of the cylindrical body is cylindrical, The position of the central axis of the chimney is calculated, and the difference obtained by subtracting the second distance, which is the distance between the central axis and the inner peripheral surface, from the first distance, which is the distance between the central axis and the inner peripheral surface, is calculated as the thickness of the lining. The method for inspecting the inside of a chimney according to claim 2.

4. The thickness of the lining is measured at an arbitrary target position on the inner circumferential surface, and the position of the central axis is calculated by comparing the measurement result with the detection result of the optical sensor at the target position. The method for inspecting the inside of a chimney according to claim 3.

5. The position of the central axis is calculated based on the detection result of the optical sensor in the exposed portion.

5. The method for inspecting the inside of a chimney according to claim 3 or 4.

6. The exposed portion includes at least one of a portion along the top of the inner surface of the barrel and a manhole-forming portion of the chimney. The method for inspecting the inside of a chimney according to claim 5.

7. The chimney has a configuration in which no lining is formed on the inner surface of the tube body, Based on the generated distribution map, the thickness of the exposed part of the steel plate that constitutes the inner surface of the tube body is calculated. The method for inspecting the inside of a chimney according to claim 1.

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