JPS63243739A - Apparatus for inspecting interior of pipe - Google Patents

Abstract

PURPOSE:To inspect the inner surface of a pipe with high accuracy and good efficiency, by providing a plate-shaped transparent body capable of distributing and projecting light on the entire periphery of the inner surface of the pipe and a two-dimensional light receiving means in an inspection unit. CONSTITUTION:A light projecting body 23 wherein a fluorescent substance is fixed to the interior of a plate-shaped transparent body 28 in a dispersed state is arranged in an inspection unit 12 and the light from a light source 21 is absorbed by the fluorescent substance to be emitted therefrom and projected from a convex lens-shaped end surface so as to be distributed to the inner surface of a pipe 1 to be inspected in the entire peripheral direction thereof. This unit 12 is held between feed wheels 18 and a motor 19 is driven and the reflected light from the inner surface of the pipe is received by a two-dimensional light receiving apparatus 25 through a lens 24. At this time, when the inner surface of the pipe is sound, a uniform circular image is drawn and, when there is corrosion or cracks on the inner surface of the pipe, a recessed image B1 is formed and, when there is rust, a protruding image B2 is formed. Since damage is judged on the basis of the uneven state of the inner surface of the pipe, inspection can be performed with high accuracy and good efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inside pipe inspection device for optically inspecting the inner surface condition of tubes such as heat exchanger tubes and various other types of piping, particularly the inner surface condition of small diameter tubes.

[Prior Art] Conventionally, devices using ultrasonic waves or light have been proposed as pipe inspection devices for small diameter pipes, and examples thereof are shown in FIGS. 5 and 6.

FIG. 5 is a schematic cross-sectional view showing a conventional pipe inspection device using ultrasonic waves. This pipe inspection apparatus includes a detection unit 2 inserted into a pipe to be inspected 1, which is provided with an ultrasonic probe 3 having an ultrasonic transmitting/receiving function and a reflecting member 4 facing the probe. That is, in this pipe inspection device, with the detection unit 2 inserted into the pipe to be inspected l, water as an ultrasonic transmission medium is injected into the pipe to be inspected 1, and the detection unit 2 is moved in the pipe axis direction. At the same time, while rotating the reflecting member 4 around the tube axis, ultrasonic waves are projected from the ultrasonic probe 3 toward the reflecting member 4, and the ultrasonic waves refracted at right angles by the reflecting member 4 are reflected into the inspected tube l. The tube to be inspected 1
The ultrasonic probe 3 receives reflected echoes from the inner and outer surfaces of the tube 1 to inspect the inner diameter, outer diameter, surface irregularities, etc. of the tube 1 to be inspected.

FIG. 6 is a schematic cross-sectional view showing a conventional pipe inspection device using light. This pipe inspection device has a detection window 5B in a cylindrical casing 5A of a detection unit 5 inserted into a pipe 1 to be inspected.
A light emitting part 6 and a light receiving part 7 are arranged at an angle so that their optical axes intersect with each other on the inner surface of the tube to be inspected l at a position facing the detection window 5B inside the casing 5A. The unit 5 is fixed to the tip of the operating shaft 8. Thereby, this pipe interior inspection device optically inspects the inner surface of the pipe to be inspected by moving the detection unit 5 in the pipe axis direction inside the pipe to be inspected 1 using the operating shaft 8 and rotating it around the tube axis. do.

[Problems to be Solved by the Invention] However, in pipe inspection devices that use ultrasonic waves, the resolution is low due to the poor convergence of the ultrasonic waves themselves, and the ultrasonic transmission medium is inside the pipe to be inspected. It is necessary to fill the barrel with water. For this reason, equipment and work for water supply, drainage, sealing, etc. are required, which results in high equipment costs and waste of work vehicles.Also, the scanning of the inner surface of the pipe to be inspected becomes a spiral, resulting in low inspection accuracy. .

In addition, even with pipe inspection equipment that uses light, the work efficiency is poor and the inner surface of the pipe to be inspected cannot be scanned! I! 5lv
The inspection accuracy is also low because it is i-shaped.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pipe inspection device with simple equipment, high work efficiency, and high inspection accuracy.

[Means for Solving the Problems] The present invention provides an in-pipe inspection apparatus for inspecting the inner surface state of the pipe to be inspected by inserting a detection unit into the pipe to be inspected and moving it in the tube axis direction, wherein the detection unit is configured to: a light source, a light projection means for distributing and projecting the light emitted from the light source, which is formed by dispersing and fixing a fluorescent substance in a plate-shaped transparent body, over the entire circumference of the inner surface of the tube to be inspected, and an optical image of the inner surface of the tube to be inspected. The light-receiving means captures the light.

[Function] The detection unit constituting the pipe inspection device of the present invention is capable of distributing and projecting the light emitted by the light source over the entire circumference of the inner surface of the pipe to be inspected using the light projecting means, and capturing an image of the reflected light from the light using the light receiving means. become. Therefore, by moving the detection unit only in the tube axis direction of the tube to be inspected under the above optical image capturing state, the inner surface state of the tube to be inspected can be inspected at any position.

Here, the pipe inspection device of the present invention does not require filling the inside of the pipe to be inspected with water, which is a transmission medium for ultrasonic waves, or screwing and moving the inspection unit, thereby simplifying the equipment and improving work efficiency. It can also be good. Moreover, the scanning by the detection unit 1 is not spiral, and the detection unit can simultaneously scan the entire circumference of the inner surface of the tube to be inspected, thereby improving inspection accuracy.

[Example] Fig. 1 is a schematic sectional view showing an in-pipe inspection device according to an embodiment of the present invention, and Fig. 2 is a schematic sectional view showing an example of a light projecting means.
Figure 3 is a schematic diagram showing the principle of inspecting the inner surface shape of tubes, and Figure 4 (
A) and (B) are schematic diagrams showing images captured by the light receiving means.

In FIG. 1, 1 is a pipe to be inspected, and 10 is an in-pipe inspection device. The pipe inspection device IO is a remote control located outside the pipe (
remote control) RR11 and a detection unit 12 inserted into the pipe. The remote control device 11 includes a detection control section 11A and a movement control section 11B.

The detection unit) 12 has a cylindrical casing 13 with both ends closed and made of a corrosion-resistant material such as metal.
Support portions 14A and 14B are formed on both end plates of 3, and 3 support leg portions 15 are fixed to each of the support portions 14A and 14B, respectively. Each support leg 15 has both support parts 14A and 14B.
The wheels 16 provided at the tip of the casing 13 are placed at 120 degrees apart from each other, and the wheels 16 provided at the tips are brought into contact with the inner surface of the tube to be inspected l, and the central axis of the casing 13 inserted into the tube to be inspected l is aligned with the center axis of the casing 13 inserted into the tube to be inspected l. 1, and the casing 13 is movable in the tube axis direction while maintaining this state in the casing 13.

Further, the detection unit 12 has one end of the tube 17 connected to the center of the rear end support portion 14B of the casing 13 in a penetrating state. The tube 17 can be bent in accordance with the bending of the tube axis of the tube 1 to be inspected, and has a rigidity that does not buckle in the axial direction. While being pinched by the feed wheel 18, an axial force is applied to move the detection unit 12 in the tube axis direction, causing the detection unit 12 to move forward/reverse. 19 is a drive motor for the feed wheel 18, 20 is a rotation amount detector for the feed wheel 18, 19A is a power supply cable, and 20A is a detection signal transfer cable.

The detection unit 12 is provided with an annular detection window 13A in which a transparent body is embedded in a certain range in the axial center of the casing 13 and over the entire circumference of the casing 13. This detection window 13A serves as an optical path for projected light from a light projector 23 to the inner surface of the tube to be inspected 1, which will be described later, and for reflected light from the inner surface of the tube to be inspected 1 toward the lens 24.

The detection unit 12 includes a light source 21, a reflector 22, and a light projecting body (light projecting means) on the central axis inside the casing 13.
23, a lens 24, and a two-dimensional light receiving device (light receiving means) 25 are arranged.

The light source 21 emits light by a light emission drive circuit 26 controlled by the remote control device 11. The light source 21 may be an incandescent lamp, a light emitting diode, a semiconductor laser, etc.;
A cable 27 desirably having many wavelength components of 000 angstroms or less is a power supply and control signal transfer cable, which is extended between the remote control device 11 and the light emitting drive circuit 26 via the inner diameter of the tube 17. There is.

The reflecting mirror 22 has a hemispherical shape surrounding the light source 21, and focuses the light emitted from the light source 21 onto the projector 23 without scattering it.

Light from the light source 21 and the reflecting mirror 22 is focused on the light projector 23. As shown in FIG. 2, the projector 23 is constructed by dispersing and fixing a fluorescent material 29 inside a transparent plate 28.
For example, (1) polymethyl methacrylate (PMMA, acrylic resin) as a matrix doped with fluorescent dyes rhodamine 6G and coumarin 6, or (2) a combination of glass and fluorescein are suitable.

Further, the light projector 23 has a reflecting surface 2 of the light receiving surface facing the light source 21.
3A is made into a mirror surface by means such as silver vapor deposition to prevent the incident light from dissipating.Thus, the light focused on the projector 23 is absorbed and emitted by the fluorescent substance 29, and then the transparent body 28 The light is projected from the end surface 28A while being reflected. The end surface 28A of the transparent body 28 is shaped like a convex lens, and its focal point is set to substantially coincide with the inner surface of the tube l to be inspected.
It has the function of focusing the light emitted from A into a beam shape toward the inner surface of the tube 1 to be inspected. That is, the light projecting body 23 distributes and projects the light collected from the light source 21 and the reflecting mirror 22 in the entire circumferential direction perpendicular to the central axis of the casing 13, and projects the light all around the inner surface of the tube 1 to be inspected. Forms a thin ring-shaped sieve surface.

The light distributed and projected onto the inner surface of the tube to be inspected 1 by the light projector 23 is reflected on the inner surface of the tube to be inspected l. This reflected light is received by the lens 24, projected onto the two-dimensional light receiving device 25, and captured. The amount of light received by each part of the inner surface of the tube to be inspected 1 captured by the two-dimensional light receiving device 25 is determined by the two-dimensional light receiving device 25.
The data captured by the two-dimensional light receiving device 25 is transferred to the remote control device 21 via the output circuit 30. Reference numeral 31 denotes a detection signal transfer cable, which is extended between the drying device 11 and the output circuit 30 via the inner diameter portion of the tube 17. As the two-dimensional light receiving device 25, a charge coupled device or the like is used.

Note that the lens 24 and the two-dimensional light receiving device 25 are
The mutual positional relationship is determined so that the image of reflected light from the inner surface of the tube to be inspected 1 captured by is projected onto the two-dimensional light receiving device 25 while being scaled down to a required ratio.

FIG. 3 is a schematic diagram showing the relationship between the distance from the central axis of the tube 1 to be inspected to the inner surface of the tube and the reflected light image projected onto the two-dimensional light receiving device 25. Assuming that the optical axes of the tubes 24 and 24 are aligned, each light reflection position giPa, Pb on the inner surface of the tube 1 to be inspected from the central axis of the tube 1 to be inspected is
, Pc are respectively La, Lb, and Lc. When the light reflected from here passes through the lens 24 and reaches the two-dimensional light-receiving device 25, the position in the two-dimensional light-receiving device 25 is ゛from the optical axis of the lens 24, respectively. The positions are ira, rb, and rc, which are separated by la, lb, and nc. These La,
Generally, the following relationship holds between distances such as Lb and Lc and distance sentences such as sentences a, sentences, and sentences C.

L= CD/F) ・Text...(1) However, D is the horizontal distance from the lens 24 to the inspection position, F
is the distance from the lens 24 to the surface of the two-dimensional light receiving device.

From the above relationship, the reflected light from the inner surface of the inspected erlft projected onto the two-dimensional light receiving device 25 will be disturbed as shown in FIG. 4(A) if the inner surface is a uniform circumferential surface with no unevenness. On the other hand, if the inner surface of the tube to be inspected 1 is corroded, cracked, damaged, etc. and has a concave shape, a concave shape is drawn as shown in Bl shown in Fig. 4 (B). For convex parts due to presence of chain parts, etc., draw a convex image as shown in B2 in Figure 4 (B). Measure the degree of concavity and convexity. Part four,
The depth and height of the convex portion are detected to obtain the inner surface shape of the tube to be inspected l. Of course, it is also possible to estimate the inner surface quality of the tube to be inspected l based on the amount of light on the inner surface of the tube ascertained from the image projected onto the two-dimensional light receiving device 25.

Next, the operation of the above embodiment will be explained.

The pipe inspection device 10 operates as follows.

(1) First, insert the detection unit 12 into the tube 1 to be inspected. The detection unit 12 is held by wheels 16 such that the center axis of the casing 13 substantially coincides with the center axis of the tube 1 to be inspected.

(The remote control device 11 moves the detection unit 12 into the inside of the tube 1 to be inspected using the tube 17 and the feeding wheel 18, and continuously or intermittently gives a light emission command signal to the light emission drive circuit 26, to emit light.

(2) The light from the light source 21 is focused by the reflecting mirror 12 onto the light projector 23, and is distributed and projected from the light projector 23 to the entire circumference of the inner surface of the tube 1 to be inspected.

■The reflected light from the inner surface of the tube to be inspected 1 is reduced and projected onto the two-dimensional light receiving device 25 via the lens 24.
5, the signal is photoelectrically converted and transferred to the remote control device 111 via the output circuit 30. As a result, the remote control device 11
At the same time, the detection amount from the rotation amount detector 20 of the feeding wheel 18 is obtained, and the correlation between the output data of the two-dimensional light receiving device 25 and the data sampling position (position of the detection unit 12) is obtained, and the The inner surface condition at each position in the axial direction of the tube 1 is inspected.

That is, the detection unit 12 constituting the pipe inspection device 10 distributes and projects the light emitted by the light source 21 onto the entire circumference of the inner surface of the pipe to be inspected l using the light projector 23, and receives the reflected light image in two dimensions. This can be captured by the device z5. Therefore, by moving the detection unit 12 only in the tube axis direction of the tube to be inspected l under the above structure capture state, the inner surface state of the tube to be inspected l can be inspected at any position.

Here, the pipe inspection device 10 fills the inside of the pipe to be inspected with water, which is a transmission medium for ultrasonic waves, and the detection unit 2 and the detection unit 12.
Since there is no need to move the A-line, etc., the equipment is simple,
Work and other things are also good. Moreover, the scanning by the detection unit 12 is not spiral, and the detection unit 12 can scan the entire circumference of the inner surface of the tube to be inspected 1 at the same time, so that the inspection accuracy is also improved.

It should be noted that the present invention can be widely applied as a pipe inspection device for pipes having various cross-sectional shapes such as rectangular shapes.

Furthermore, in implementing the present invention, the detection unit may be self-propelled, such as having a built-in intra-tube moving means.

[Effects of the Invention] As described above, according to the present invention, equipment can be simplified, work efficiency can be improved, and high inspection accuracy can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an in-pipe inspection device according to an embodiment of the present invention, FIG. 2 is a schematic sectional view showing an example of a light projecting means,
Figure 3 is a schematic diagram showing the principle of inspection of tube surface shape, Figure 4 (A
), (B) are schematic diagrams showing images captured by the light receiving means, Figure 5 is a schematic cross-sectional view showing a conventional pipe inspection device using ultrasonic waves, and Figure 6 is a conventional pipe inspection device using light. FIG. 1... Pipe to be inspected, 10... In-pipe inspection device. 12...Detection unit, 21...Light source. 23... Light projecting body (light projecting means), 25... Two-dimensional light receiving device (light receiving means), 28... Transparent body, 29... Fluorescent substance. Agent Patent Attorney Osamu Shiokawa 2nd Session Figure 3 1'X rc' Figure 4 (A) (8) Figure 5 Figure 6

Claims (1)

[Claims] (1) In an in-pipe inspection device that inspects the inner surface condition of the tube to be inspected by inserting a detection unit into the tube to be inspected and moving it in the tube axis direction, the detection unit includes a light source and a fluorescent substance in the transparent plate-like body. It is characterized by having a light projecting means for distributing and projecting the light emitted from the light source formed by dispersing and fixing the light source over the entire circumference of the inner surface of the tube to be inspected, and a light receiving means for capturing a light image of the inner surface of the tube to be inspected. Pipe inspection equipment.