JP2013019786A - Inside tube wall inspection apparatus and inside tube wall inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inside tube wall inspection apparatus and an inside tube wall inspection method capable of inspecting an inside tube wall independently of states and dimensions of the inside tube wall.SOLUTION: The inside tube wall inspection apparatus includes: projection means 11 for projecting pattern light P1 having a pattern to an inspection portion in the inside of a tube 2 over a peripheral direction of the inside of the tube 2; indication means 12 for projecting the pattern light projected and reflected to/from the inspection portion as reflected pattern light P2; and observation means 13 for observing a shape of the reflected pattern light P2.

Description

  The present invention relates to a pipe inner surface inspection apparatus and an inspection method for inspecting an inner surface of a pipe.

  In plant facilities such as power plants and chemical plants, many tubular structures such as piping (hereinafter simply referred to as “piping”) are installed. The inner surface of the pipe is deteriorated by liquid, gas, or water vapor passing through the pipe.

  Conventionally, as a technique for diagnosing deterioration, for example, a capsule-like device equipped with an imaging device for visually confirming the inside of a pipe (see, for example, Patent Document 1), or stereo vision using a plurality of imaging devices There is known a system for measuring the dimensions of an object (for example, see Patent Document 2).

JP 2007-10513 A JP 2009-282274 A

  In order to check the deformation inside the pipe by inserting the apparatus inside the pipe, it is necessary to use a technique such as stereo vision using a plurality of observation devices such as a CCD camera. When performing stereo viewing, a mark is required for each pixel to ensure that the same part is observed by a plurality of observation devices.

  However, when the pipe diameter is large, 360 degrees in the pipe circumferential direction cannot be observed by one stereo view, and it is necessary to divide and observe every 180 degrees, for example. Further, when the inner surface of the pipe has a strong metallic luster, the inner surface of the pipe does not absorb the mark light and it is difficult to set the mark. From the above points, there is a limit to using stereo vision for observation of the inner surface of the pipe.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a pipe inner surface inspection apparatus and an inspection method thereof that can inspect a pipe inner surface regardless of the state and dimensions of the pipe inner surface. To do.

  In order to solve the above-described problems, a pipe inner surface inspection apparatus according to the present invention projects pattern light having a pattern on an inspection spot on the pipe inner face over the circumferential direction of the pipe inner face, and is projected on the inspection spot. It is characterized by comprising display means for projecting the reflected pattern light as reflected pattern light, and observation means for observing the shape of the reflected pattern light.

  In the pipe inner surface inspection apparatus and the inspection method according to the present invention, the pipe inner surface can be inspected regardless of the state and dimensions of the pipe inner surface.

The lineblock diagram of the pipe inner surface inspection device in a 1st embodiment. The block diagram of a pipe inner surface inspection apparatus provided with the fan as a dust removal apparatus. The block diagram of a pipe inner surface inspection apparatus provided with the wiper as a dust removal apparatus. Explanatory drawing which shows the example of a pattern light display when a deposit arises in the piping inner surface. Explanatory drawing which shows the example of a display of the pattern light when thickness reduction arises in the piping inner surface. The lineblock diagram of the pipe inner surface inspection device in a 2nd embodiment. The lineblock diagram of the tube inner surface inspection device which shows the 1st example of arrangement of a light source and a pattern projection device. The lineblock diagram of the tube inner surface inspection device which shows the 2nd example of arrangement of a light source and a pattern projection device. The block diagram of the pipe inner surface inspection apparatus which shows the other example of arrangement | positioning of a pattern projector. The block diagram which shows the modification of a pipe inner surface inspection apparatus. The block diagram which shows the other modification of a pipe inner surface inspection apparatus.

[First Embodiment]
A first embodiment of a pipe inner surface inspection apparatus and inspection method according to the present invention will be described with reference to the accompanying drawings. In each embodiment, an example in which the inspection target of the pipe inner surface inspection apparatus and the inspection method thereof is a pipe having a circular radial cross section will be described.

  FIG. 1 is a configuration diagram of a pipe inner surface inspection apparatus 1 according to the first embodiment.

  The tube inner surface inspection device 1 includes a pattern projection device 11, a screen 12, a photographing device 13, an illumination device 14, a viewpoint changing device 15, a fixing device 16, and a position specifying device 17.

  The pattern projection device 11 has a light source and projects the pattern light P1 on the inner surface of the pipe 2 to be inspected. There is no restriction | limiting in the wavelength of a light source, An ultraviolet-ray, visible light, and infrared rays may be sufficient. The light may be continuous light or pulsed light. The light source may be installed outside the pipe 2, and light may enter the pipe 2 through an incident window or the like. Further, the light source itself may be inserted into the pipe 2 or may be inserted into the pipe 2 using an optical fiber or the like.

  The pattern projection device 11 generates, for example, circular light using an axicon lens or cylindrical lens, line light using a cylindrical lens, or interference draft using a grating, slit, or pinhole. Hereinafter, patterned light such as circular light, line light, and interference fringes formed by the pattern projector 11 is referred to as pattern light.

  The screen 12 absorbs and displays the pattern light P2 (reflected pattern light) that is the reflected light of the pattern light P1 on the inner surface of the pipe 2. The screen 12 may be any material that absorbs and emits light with respect to the wavelength of the light source employed in the pattern projector 11. Any material other than the surface irradiated with the pattern of the screen 12 can be applied. The shape of the screen 12 may be any shape that can be inserted into the pipe 2.

  The screen 12 has a fan 21 and a wiper 22 as a dust removing device.

  FIG. 2 is a configuration diagram of the pipe inner surface inspection apparatus 1 including a fan 21 as a dust removing apparatus.

  FIG. 3 is a configuration diagram of the pipe inner surface inspection apparatus 1 including the wiper 22 as a dust removing apparatus.

  In FIGS. 2 and 3, only the configuration necessary for the description is shown, and other configurations are omitted.

  The dust remover removes impurities on the surface of the screen 12. The fan 21 is provided, for example, at the center position of the screen 12 which is effective for removing impurities on the screen 12. The wiper 22 rotates around the center position of the screen 12 to remove impurities on the screen 12. Note that the screen 12 may have both the fan 21 and the wiper 22 or may have either one.

  The imaging device 13 takes an image to observe the pattern light P <b> 2 displayed on the screen 12 and the inspection object reflected by the viewpoint changing device 15. The photographing device 13 is arranged at a position where the observation target projected on the screen 12 and the viewpoint changing device 15 can be photographed. The photographing device 13 is a device suitable for the environment in the pipe 2 such as a CCD camera, a CMOS camera, a single-lens reflex camera, or a video camera.

  The illumination device 14 illuminates the inspection location inside the pipe 2 toward the imaging device 13. Unlike the pattern light, the illumination device 14 irradiates a wide area of the pipe using a ring-shaped light guide or the like. The light source is preferably one that can generate light regardless of wavelength, such as an LED light. In addition, the illuminating device 14 should just be arrange | positioned in the position which illuminates the piping 2 inner surface not only on the screen 12 (screen 12 circumference | surroundings) like FIG.

  The viewpoint changing device 15 is disposed between the screen 12 and the photographing device 13, and causes the photographing device 13 to observe an image of the inner surface of the pipe 2. The viewpoint changing device 15 has a high reflectance with respect to the wavelength of light projected by the pattern projection device 11, and is, for example, an aluminum mirror or a glass mirror.

  The fixing device 16 is a device for fixing the positional relationship between the pattern projection device 11 and the screen 12 and moving them within the pipe 2. The fixing device 16 may further fix the photographing device 13, the illumination device 14, and the viewpoint changing device 15.

  The position specifying device 17 specifies the inspection position of the pipe inner surface inspection device 1. The position specifying device 17 is, for example, a laser positioning meter that calculates the moving distance of the tube inner surface inspection device 1 from the arrival time of light, or a mechanical device for controlling the insertion distance of the tube inner surface inspection device 1 inserted into the pipe 2. A mechanism provided with a distance measuring function can be applied. Moreover, in order to evaluate the position of the unevenness | corrugation in the circumferential direction of the piping 2, the position specification apparatus 17 can also apply geomagnetic sensors, such as an electronic compass, a gyro sensor, and an acceleration sensor.

  Next, the operation of the pipe inner surface inspection apparatus 1 in the first embodiment will be described.

  Inside the pipe 2, an event occurs in which the inner diameter of the pipe 2 is reduced due to deposition or adhesion of substances contained in the pipe 2, and an event in which the inner diameter of the pipe is increased due to a decrease in the thickness of the pipe 2. The pipe inner surface inspection apparatus 1 is used for inspecting the occurrence of these events.

  First, the pipe inner surface inspection apparatus 1 is inserted into the pipe 2 and moved to a position where the pattern projection apparatus 11 projects the pattern light P1 on the inspection location. The pattern projection device 11 projects the pattern light P1 on the inspection location on the inner surface of the pipe 2.

  For example, when the pattern projection device 11 projects a regular circular pattern light P1 onto the cylindrical pipe 2, the pattern projection device 11 projects the pattern light P1 onto the inner surface of the pipe 2 at a projection angle θ. The pattern light P1 is projected uniformly (over 360 degrees in the circumferential direction) on the circumferential direction of the inner surface of the pipe 2 at the same position in the axial direction of the pipe 2. The pattern light P1 is reflected on the inner surface of the pipe 2, and the reflected light is displayed on the screen 12 as a circular pattern light P2.

  The imaging device 13 images and observes the pattern light P2 displayed on the screen 12. The shape of the observed pattern light P2 is determined by calculating the position where the brightness of the pattern is highest and the brightness center of gravity by image processing.

  Here, when the inner diameter of the pipe 2 is uniform in the circumferential direction, the screen 12 displays the circular pattern light P2. However, if the inner surface of the pipe 2 is uneven due to the occurrence of deposits or thinning, the light emitted from the pattern projection device 11 is not regularly reflected on the inner surface of the pipe 2, and the pattern light P2 is distorted and displayed.

  The pipe inner surface inspection apparatus 1 observes the change in the inner diameter of the pipe 2 by observing the shape of the pattern light P2 with the photographing apparatus 13.

  FIG. 4 is an explanatory view showing a display example of the pattern light P <b> 2 when the deposit 3 is generated on the inner surface of the pipe 2.

  FIG. 5 is an explanatory diagram showing a display example of the pattern light P2 when the thinning 4 occurs on the inner surface of the pipe 2.

  As shown in FIG. 4, the radius of the pipe 2 (distance from the center) at normal time is r, whereas the place where the deposit 3 is generated on the inner surface of the pipe 2 has a radius r ′ smaller than the radius r. . Therefore, the pattern light reflected at the position where the deposit 3 is generated (radius r ′ position) and displayed on the screen 12 is the radius (from the center) of the pattern light P2 projected when the radius of the pipe 2 is r. The radius R ′ is smaller than the distance (R).

  As shown in FIG. 5, the portion where the thinning 4 occurs on the inner surface of the pipe 2 has a radius r ′ larger than the radius r. Therefore, the pattern light reflected and displayed on the screen 12 at the position where the thinning 4 occurs (radius r ′ position) is larger than the radius R of the pattern light P2 projected when the radius of the pipe 2 is r. Radius R ′.

  Thus, the pipe inner surface inspection apparatus 1 can inspect the change in the inner diameter of the pipe 2 by observing the shape of the pattern light P2 displayed on the screen 12.

  Here, since the distance between the pattern projection device 11 and the screen 12 and the projection angle θ of the pattern projection device 11 are values unique to the tube inner surface inspection device 1, the radius of the inner surface of the pipe 2 is determined based on the shape of the pattern light P2. Increase or decrease can be calculated.

  When the inner diameter of the pipe 2 at the inspection location is uniform in the axial direction, that is, when the inner surface of the pipe 2 is parallel to the axial direction, the distance between the pattern projection device 11 and the screen 12 is L, and the radius of the inner surface of the pipe 2 is r. Assuming that the projection angle of the pattern light P1 by the pattern projection device 11 is θ, the radius R of the pattern light P2 displayed on the screen 12 is expressed by Expression (1).

[Equation 1]
R = 2r-Ltanθ (1)

  Assuming that the radius r has increased or decreased by Δr due to the occurrence of the deposit 3 or the thinning 4, the change amount ΔR is {2 (r + Δr) −Ltanθ} − {2r−Ltanθ} = 2Δr from the equation (1). The range of the pipe 2 in which the change of the radius r has occurred can be confirmed by scanning along the axial direction of the pipe 2 and observing the increase / decrease in the radius of the projected pattern light P2.

  Further, when the inner surface of the pipe 2 at the inspection location is inclined with respect to the axial direction, or when the inner surface of the pipe 2 is tilted by Φ degrees compared to the normal state due to the occurrence of deposits 3 or the like, the normal reflection angle is 2Φ. Therefore, the radius R of the pattern light P2 is as shown in Expression (2).

  Since θ and L in the expressions (1) and (2) are values specific to the apparatus, the radius R of the pattern light P2 can be expressed as a function of the radius r of the inner surface of the pipe 2 and the inclination Φ with respect to the axial direction.

  In the pipe inner surface inspection apparatus 1, if impurities such as dust, dust or water droplets in the pipe 2 adhere to the screen 12, whether the change in the shape of the pattern light P <b> 2 is due to irregularities on the inner face of the pipe 2, or impurities on the screen 12. It may be difficult to evaluate whether this is the case. Therefore, by removing impurities with the dust removal device of the fan 21 and the wiper 22 at the start of inspection or during inspection, it is ensured that the deformation of the pattern light P2 is due to the deformation of the inner surface of the pipe 2, and highly accurate inspection. Can be implemented.

  Moreover, since the pipe inner surface inspection apparatus 1 includes the illumination device 14 and the viewpoint changing device 15, it is possible to visually recognize a place where an abnormality has been confirmed in the pipe 2 as described above.

  The illumination device 14 irradiates light around the inspection location. The viewpoint changing device 15 reflects an image of the illuminated inner surface of the pipe 2, and the photographing device 13 photographs this image. The inspector can observe the inner surface of the pipe 2 from the front by checking the image of the imaging device 13. Moreover, since the pipe inner surface inspection apparatus 1 includes the position specifying device 17, it is possible to specify the position where the abnormality is confirmed.

  The pipe inner surface inspection apparatus 1 and the inspection method in the first embodiment as described above can inspect the shape of the inner surface of the pipe 2 regardless of the state of the inner surface of the pipe 2 and the size of the pipe diameter.

  Specifically, even if the inner surface of the pipe 2 has a metallic luster so that light is reflected and it is difficult to use an inspection method using stereo vision, the reflection on the inner surface of the pipe 2 is utilized. Changes in the pipe diameter can be observed and the deformation length can be evaluated.

  Further, by adjusting the projection angle of the pattern projection device 11, the circumferential direction 360 degrees of the pipe 2 can be inspected at a time regardless of the pipe diameter. That is, the pipe inner surface inspection apparatus 1 can inspect a wide range at a time. For this reason, the pipe inner surface inspection apparatus 1 only needs to scan the pipe 2 in the axial direction, and the inspection time can be shortened.

  Furthermore, the tube inner surface inspection apparatus 1 can observe the inspection object from the front simultaneously with observing the pattern light P2 depending on the shape of the observation object, and can evaluate the color and shape of the unevenness. The pipe inner surface inspection apparatus 1 can also be used for investigating the type of deposits on the pipe 2 and the cause of deterioration.

  Moreover, since the pipe inner surface inspection apparatus 1 can identify the location where an abnormality has been found, it is possible to minimize the work steps such as replacement and repair of the pipe 2.

[Second Embodiment]
2nd Embodiment of the pipe | tube inner surface inspection apparatus which concerns on this invention is described based on an accompanying drawing.

  FIG. 6 is a configuration diagram of the pipe inner surface inspection apparatus 31 in the second embodiment.

  The pipe inner surface inspection apparatus 31 in the second embodiment is different from the first embodiment in that a plurality of pattern projection apparatuses are provided. Components and parts corresponding to those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The pattern projection device 11a projects the pattern light P1a at the projection angle θa on the inner surface of the pipe 2 that is the inspection location. The pattern projection device 11b projects the pattern light P1b onto the inner surface of the pipe 2 at a projection angle θb. The projection angles θa and θb are set so as to project the pattern lights P1a and P1b at substantially the same position on the inner surface of the pipe 2.

  The pattern projection devices 11 a and 11 b are fixed on the same axis of the pipe 2 by the fixing device 16 at different distances to the screen 12. The pattern projection apparatuses 11a and 11b may be able to distinguish the pattern lights P1a and P1b by changing the wavelength of the generated light or by changing the irradiation timing.

  The pattern projectors 11a and 11b each have a light source. The pattern projection apparatuses 11a and 11b may have light sources individually, or may use a common light source as shown in FIGS.

  FIG. 7 is a configuration diagram of the tube inner surface inspection device 31 showing a first arrangement example of the light source 32 and the pattern projection devices 11a and 11b.

  The pattern projection devices 11a and 11b split the light emitted from one light source 32 into two using a spectroscopic device 33 such as a beam splitter. The split light is adjusted in optical path by the mirror 34 and then incident on the pattern projectors 11a and 11b.

  FIG. 8 is a configuration diagram of the tube inner surface inspection apparatus 31 showing a second arrangement example of the light source 32 and the pattern projection apparatuses 11a and 11b.

  The pattern projector 11a has an optical path 35 at the center along the axial direction. The light emitted from the light source 32 passes through the optical path 35 and is incident on the pattern projection device 11b.

  The screen 12 absorbs the pattern light P2a that is the reflected light of the pattern light P1a on the inner surface of the pipe 2 and displays it. Further, the screen 12 absorbs and displays the pattern light P2b that is the reflected light of the pattern light P1b on the inner surface of the pipe 2.

  Next, the operation of the pipe inner surface inspection apparatus 31 in the second embodiment will be described.

  As described in the first embodiment, the radii Ra and Rb (radius R) of the pattern lights P2a and P2b projected on the screen 12 are expressed by the above-described equation (2).

  The projection angles θa and θb (projection angle θ) of the pattern projection apparatuses 11a and 11b and the distances La and Lb (distance L) between the pattern projection apparatuses 11a and 11b and the screen 12 in the equation (2) are values specific to the apparatus. It is. For this reason, the radius R in the equation (2) is a function having the variables of the inclination Φ with respect to the axial direction of the inner surface of the pipe 2 and the radius (distance from the center of the pipe 2 to the inner surface) r of the inner surface of the pipe 2.

  Since the pipe inner surface inspection device 31 includes a plurality of pattern projection devices 11a and 11b, a simultaneous equation is obtained from two equations having the gradient Φ and the radius r as variables. The shape of the inner surface of the pipe 2 can be obtained by solving these simultaneous equations.

  At this time, the fixing device 16 fixes the pattern projection devices 11a and 11b and the screen 12 on the same axis. As a result, the distances La and Lb between the pattern projection apparatuses 11a and 11b and the screen 12, which are parameters appearing in the expression (2), and the geometric relationship between the tube inner surface inspection apparatus 31 are fixed. The tube inner surface inspection apparatus 31 can observe the pattern lights P2a and P2b projected on the screen 12 under the same conditions.

  FIG. 9 is a configuration diagram of the tube inner surface inspection device 31 showing another arrangement example of the pattern projection devices 11a and 11b.

  The pattern projection device 11 b irradiates light in a direction perpendicular to the axial direction of the pipe 2 from a position at a distance Lb from the screen 12. That is, the pattern projection device 11b irradiates light so that the projection angle θb is 90 degrees.

  The pattern light P2b formed by the light emitted from the pattern projection device 11b is totally reflected by the inner surface of the pipe 2 when the inner surface of the pipe 2 is parallel to the axial direction. Therefore, the pattern light P2b is not displayed on the screen 12.

  On the other hand, when the inner surface of the pipe 2 has an inclination Φ with respect to the axial direction, the pattern light P2b formed by the light irradiated from the pattern projection device 11b is reflected in a direction depending on the inclination of the inner surface of the pipe 2. . Therefore, the pattern light P2b is displayed on the screen 12.

  The tube inner surface inspection device 31 can inspect the presence or absence of the inclination of the inner surface of the pipe 2 based on the presence or absence of the pattern light P2b, and from the distances Ra and Rb to the center of the screen 12 obtained from the two types of pattern light P2a and P2b. The inner diameter (radius r ′) and inclination Φ of the pipe 2 can be calculated.

  The pipe inner surface inspection device 31 and the inspection method thereof in the second embodiment are not only the degree of deformation but also the pipe 2 by observing the radii Ra and Rb of the pattern lights P2a and P2b in addition to the effects exhibited in the first embodiment. The shape of the inner surface of the pipe 2 including the inner surface inclination Φ can be specified.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  FIG. 10 is a configuration diagram showing a modification of the pipe inner surface inspection apparatus.

  FIG. 11 is a configuration diagram showing another modification of the pipe inner surface inspection apparatus.

  For example, the imaging device 13 may be installed coaxially with the pattern projection device 11 and may be installed between the pattern projection device 11 and the screen 12 or at a position further away from the screen 12 than the pattern projection device 11.

  The viewpoint changing devices 15A and 15B may have a planar shape such as a polygon or a circle, or a solid shape such as a cone. In this case, the photographing device 13 is arranged at a position where the inner surface of the pipe 2 reflected by the viewpoint changing devices 15A and 15B can be photographed.

  Further, the screen 12 may be a plurality of cameras having the same configuration as the photographing device 13 and capable of projecting the pattern light P2, and may measure the intensity distribution of the pattern light P2 from the obtained projection image.

DESCRIPTION OF SYMBOLS 1, 31 Pipe inner surface inspection apparatus 2 Piping 11, 11a, 11b Pattern projection apparatus 12 Screen 13 Imaging apparatus 14 Illumination apparatus 15, 15A, 15B View point change apparatus 16 Fixing apparatus 17 Position specifying apparatus 21 Fan 22 Wiper 32 Light source 33 Spectroscopic apparatus 34 Mirror 35 Optical path P1, P2, P1a, P2a, P1b, P2b Pattern light

Claims (8)

Projecting means for projecting pattern light having a pattern at an inspection location on the inner surface of the tube over the circumferential direction of the inner surface of the tube;
Display means for projecting the pattern light projected and reflected on the inspection location as reflected pattern light;
A tube inner surface inspection apparatus comprising observation means for observing the shape of the reflection pattern light. 2. The tube inner surface according to claim 1, wherein a plurality of the projecting units are provided at different coaxial positions along the tube axis, and the plurality of projecting units respectively project the pattern light onto substantially the same position of the tube inner surface. Inspection device. The pipe inner surface inspection apparatus according to claim 2, wherein one of the plurality of projection means projects pattern light in a direction perpendicular to an axial direction of the pipe. The pipe inner surface inspection apparatus according to any one of claims 1 to 3, further comprising a fixing unit that fixes an arrangement relationship between the projection unit and the display unit. Illuminating means for illuminating the inspection location;
The pipe inner surface inspection apparatus according to any one of claims 1 to 4, further comprising a reflection unit that reflects an image of the inspection portion and causes the observation unit to observe the image. The pipe inner surface inspection apparatus according to claim 1, further comprising position specifying means for specifying the inspection portion on the inner surface of the pipe. The pipe inner surface inspection apparatus according to claim 1, further comprising dust removing means for removing impurities adhering to the display means. A projection step of projecting pattern light having a pattern at an inspection location on the inner surface of the tube over the circumferential direction of the inner surface of the tube;
A reflection step of reflecting the pattern light projected on the inspection location at the inspection location;
A display step of projecting the reflected reflection pattern light;
An observation step of observing the shape of the reflection pattern.

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