JPH0619333B2 - In-pipe inspection device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pipe inspecting apparatus for optically inspecting the pipe inner surface condition of heat exchanger pipes and other various pipes, especially the inner surface condition of a small diameter pipe.

[Prior Art] Conventionally, as an in-pipe inspection device for a small-diameter pipe, a device using ultrasonic waves or light has been proposed, and one example thereof is shown in Figs. 5 and 6.

FIG. 5 is a schematic sectional view showing a conventional in-pipe inspection device using ultrasonic waves. In this in-pipe inspection device, an ultrasonic probe 3 having an ultrasonic wave transmitting / receiving function and a reflecting member 4 facing the ultrasonic probe 3 are provided in a detection unit 2 inserted in an inspected tube 1. That is, this in-pipe inspection apparatus injects water as an ultrasonic wave transmission medium into the inspected tube 1 with the detection unit 2 inserted in the inspected tube 1 to move the detection unit 2 in the tube axis direction. While moving and rotating the reflecting member 4 around the tube axis, ultrasonic waves are projected from the ultrasonic probe 3 toward this, and the ultrasonic waves refracted at right angles by the reflecting member 4 of the tube 1 to be inspected. It is incident on the inner surface, and the tube to be inspected 1
The ultrasonic probe 3 receives the reflection echoes from the inner surface and the outer surface, and inspects the inner diameter, the outer diameter, the unevenness of the surface, etc. of the tube 1 to be inspected.

FIG. 6 is a schematic sectional view showing a conventional in-tube inspection device using light. This in-pipe inspection device includes a detection unit 5B in a cylindrical casing 5A of a detection unit 5 inserted into an inspection pipe 1.
Is provided, and the light projecting section 6 and the light receiving section 7 are arranged at a position facing the detecting section 5B inside the casing 5A so that their optical axes intersect each other on the inner surface of the tube 1 to be inspected, and this detection is performed. The unit 5 is fixed to the tip of the operation shaft 8. As a result, this in-pipe inspection device uses the operation shaft 8 to detect the detection unit 5
Is rotated around the tube axis while being moved in the tube axis direction inside the tube to be inspected 1 to optically inspect the inner surface of the tube to be inspected 1.

[Problems to be Solved by the Invention] However, in the in-pipe inspection apparatus using ultrasonic waves, the resolution is low due to the poor convergence of the characteristics of the ultrasonic waves themselves, and the ultrasonic transmission medium inside the tube to be inspected. It is necessary to fill it with dripping water. Therefore, equipment and work for water supply, drainage, sealing, etc. are required, resulting in high equipment cost and poor work efficiency. Further, the scanning of the inner surface of the pipe to be inspected becomes spiral, and the inspection accuracy is low.

Further, even in the in-pipe inspection device using light, the work efficiency is low and the inspection accuracy is low because the scanning of the inner surface of the inspected pipe becomes spiral.

Incidentally, in JP-A-61-270600, the moving object (2),
Inspecting the wall surface by attaching the objective lens (8a) of the wall surface device (3), (4) and the light projectors (6), (8) that illuminate the imaged part of the wall surface by the objective lens (3a) A device for irradiating the light projecting devices (6) and (8) with a diffuse light projecting part (6a) that illuminates a wall surface in a wide range, and irradiating slit light in an irradiation range of the diffuse light projecting part (6a). A wall surface inspection device provided with a light condensing and projecting portion (6b) is described.

However, in the invention described in the above-mentioned Japanese Patent Laid-Open No. 61-270600, the light projecting system is composed of two types, a diffuse light projecting section and a condensing light projecting section, and the entire diffused illumination is included. Since the slit light is projected onto, the S / N is poor when focusing on only the slit light, which makes it unsuitable for automatic recognition of the shape of the slit light. Further, since the condensing and projecting system is formed so that the imaging of the slit light by the objective lens becomes substantially a circle when there is no foreign matter in the tube, the shape can be determined only qualitatively.

The present invention automatically and quantitatively recognizes the shape of the pipe to be inspected,
It is an object of the present invention to provide an in-pipe inspection device that has a simple facility, high work efficiency, and high inspection accuracy.

[Means for Solving the Problem] The present invention relates to an in-pipe inspection apparatus that inserts a detection unit into a pipe to be inspected and moves in the pipe axis direction to inspect an inner surface state of the pipe to be inspected, and a central axis of the detection unit. Emitted from the light source in which the optical axis is set so as to match with, and the fluorescent substance is dispersed and fixed in the plate-shaped transparent body, and the condensing lens structure is provided in the peripheral portion of the plate-shaped transparent body. Projecting means for distributing and projecting the emitted light all around the inner surface of the tube to be inspected, light receiving means for capturing an optical image of the inner surface of the tube to be inspected, and the shape of the tube to be inspected quantitatively from the output of the light receiving means. And a detection control unit for outputting.

[Operation] The detection unit that constitutes the in-tube inspection device of the present invention is capable of distributing and projecting the light emitted from the light source by the light projecting means onto the entire circumference of the inner surface of the tube to be inspected, and capturing the reflected light image from this by 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 optical image capturing state, the inner surface state of the tube to be inspected can be inspected at any position.

Here, the in-pipe inspection apparatus of the present invention does not need to fill the inside of the pipe to be inspected with water as an ultrasonic transmission medium or to spirally move the detection unit, so that the equipment can be simplified and work efficiency can be improved. Can be good. Further, the scanning by the detection unit does not have a spiral shape, and the detection unit can simultaneously scan the entire circumference of the inner surface of the pipe to be inspected, so that the inspection accuracy is also improved.

Further, in the present invention, (a) since the light projecting system is constituted only by the condensing light projecting section, the shape of the tube to be inspected can be automatically recognized well by projecting only the slit light. Further, (b) since the optical axis is set on the central axis of the detection unit, the light source, the reflecting mirror, the light projecting body, the lens, the two-dimensional light receiving device, etc. are arranged on the central axis, and the respective optical distances are also set. This is set, and the shape of the pipe to be inspected can be quantitatively recognized, for example, according to the equation (1) described later. That is, the present invention has (a), (b) automatic recognition, a detection control unit for performing a quantitative calculation, and as a result, automatically and quantitatively recognizes the shape of the pipe to be inspected, and with simple equipment. It is possible to obtain an in-pipe inspection device that has good work efficiency and high inspection accuracy.

[Embodiment] 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.
FIG. 3 is a schematic diagram showing the principle of inspecting the tube inner surface shape, and FIGS. 4 (A) and 4 (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 in-pipe inspection device 10 has a remote control (remote control) device 11 located outside the pipe and a detection unit 12 inserted into the pipe. The remote control device 11 includes a detection control unit 11A and a movement control unit 11B.

The detection unit 12 has a cylindrical casing 13 made of a corrosion-resistant material such as metal and having both ends closed.
Support portions 14A and 14B are formed on both end plates of No. 3, and three support leg portions 15 are fixed to each of the support portions 14A and 14B. Each support leg portion 15 includes both support portions 14A and 14B.
In each case, the wheels 16 provided at the tips are abutted against the inner surface of the pipe to be inspected 1 and the central axis of the casing 13 inserted into the pipe to be inspected 1 1 is arranged so as to be substantially coincident with the central axis, and the casing 13 is movable in the pipe axis direction while maintaining this state in the casing 13.

Further, in the detection unit 12, one end of the tube 17 is connected to the center of the rear end support portion 14B of the casing 13 in a penetrating state. The tube 17 has a rigidity that allows it to bend following the bending of the tube axis of the tube 1 to be inspected, and does not buckle in the axial direction, and is provided outside the tube by tube feeding means such as a pair of upper and lower tubes. While being pinched by the feed wheel 18, an axial force is applied to move it in the tube axis direction, and the detection unit 12 is moved forward / backward. Reference numeral 19 is a drive motor of the feed wheel 18, 20 is a rotation amount detector of the feed wheel 18, 19A is a power supply cable, and 20A is a detection signal transfer cable.

The detection unit 12 includes an annular detection window 13 </ b> A in which a transparent body is embedded in the entire area of the casing 13 in a certain range of the central portion in the axial direction of the casing 13. The detection window 13A serves as an optical path of projection light from a light projecting body 23, which will be described later, to the inner surface of the tube 1 to be inspected and reflected light traveling from the inner surface of the tube 1 to be inspected to the lens 24.

The detection unit 12 has a light source 21, a reflecting mirror 22, a light projecting body (light projecting means) 23, a lens 24, and a two-dimensional structure, the optical axis of which is set on the central axis inside the casing 13 so as to coincide with the central axis. A light receiving device (light receiving means) 25 is arranged.

The light source 21 is emitted 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, or the like.
Although it is desirable to have many wavelength components of 00 angstroms or less, 27 is a cable for feeding and controlling signals, which is provided between the remote control device 11 and the light emission drive circuit 26 via the inner diameter portion of the tube 17. ing.

The reflecting mirror 22 has a hemispherical shape surrounding the light source 21, and focuses the light emitted from the light source 21 on the light projecting body 23 without dissipating the light.

Light from the light source 21 and the reflecting mirror 22 is focused on the light projecting body 23. As shown in FIG. 2, the light projecting body 23 is configured by dispersing and fixing a fluorescent substance 29 inside a plate-shaped transparent body 28.
For example, it is preferable to use methyl polymethallylate (PMMA, acrylic resin) as a matrix and dope the fluorescent dyes rhodamine 6G and coumarin 6 or a combination of glass and fluorescein. The light projecting body 23 has a surface 23 opposite to the light receiving surface facing the light source 21.
A is mirror-finished by means such as silver vapor deposition to prevent incident light from being dissipated. As a result, the light condensed on the light projecting body 23 is absorbed and emitted by the fluorescent substance 29, reflected by the transparent body 28, and projected from the end face 28A. End face 2 of transparent body 28
8A has a convex lens shape (lens structure for condensing light), and its focus is set so as to be substantially coincident with the inner surface of the tube 1 to be inspected, and the light projected from the end face 28A is the inner surface of the tube 1 to be inspected. It has the function of squeezing it in a beam shape toward. In the implementation of the present invention, the focusing lens structure of the peripheral portion of the transparent body 28 does not necessarily have to be placed on the inner surface of the tube 1 to be inspected, and can be inspected if a fine projection light is obtained to some extent. Is. That is, the light projecting body 23 distributes and projects the light condensed from the light source 21 and the reflecting mirror 22 in the entire circumferential direction orthogonal to the central axis of the casing 13, and is thin on the entire inner surface of the inspected tube 1. A ring-shaped bright surface is formed.

The light that is distributed and projected onto the inner surface of the tube 1 to be inspected by the light projecting body 23 is reflected on the inner surface of the tube 1 to be inspected. The reflected light is received by the lens 24, projected on 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 photoelectrically converted in the two-dimensional light receiving device 25, and the captured data of the two-dimensional light receiving device 25 is passed through the output circuit 30 to the remote controller 11. Is transferred to the detection control unit 11A. Reference numeral 31 is a detection signal transfer cable, which extends between the remote control device 11 and the output circuit 30 via the inner diameter of the tube 17. A charge coupled device or the like is used as the two-dimensional light receiving device 25.

The lens 24 and the two-dimensional light receiving device 25 are
The positional relationship is determined so that the reflected light image from the inner surface of the tube 1 to be inspected captured in 1 is projected on the two-dimensional light receiving device 25 in a scaled state at a required ratio.

FIG. 3 is a schematic diagram showing the relationship between the distance from the central axis of the tube to be inspected 1 to the inner surface of the tube and the reflected light image projected on the two-dimensional light receiving device 25. Now, the central axis of the tube to be inspected 1 and the lens are shown. Assuming that the optical axes of 24 coincide with each other, the light reflection positions Pa, Pb on the inner surface of the tube 1 to be inspected from the central axis of the tube 1 to be inspected,
If the distances to Pc are La, Lb, and Lc, respectively,
When the light reflected from this reaches the two-dimensional light receiving device 25 through the lens 24, the positions in the two-dimensional light receiving device 25 are ra, rb, and rc respectively separated from the optical axis of the lens 24 by la, lb, and lc. Becomes These La and L
The following relationship is generally established between the distance L such as b and Lc and the distance l such as la, lb and lc.

L = (D / F) · l (1) where 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 tube 1 to be inspected projected onto the two-dimensional light receiving device 25 is as shown in FIG. 4 (A) when the inner surface is a uniform circumferential surface without unevenness. Draws a circular image without distortion. On the other hand, the inner surface of the pipe 1 to be inspected is corroded,
A concave image such as B1 shown in FIG. 4 (B) is drawn for a concave portion where cracks, damaged portions, etc. exist.
In addition, a convex image is drawn as shown by B2 in FIG. 4 (B) for the convex portion due to the presence of a rust portion or the like. The output of the two-dimensional light receiving device 25 having the concave shape and the convex shape is received,
The detection control unit 11A performs a calculation based on the equation (1) to obtain a quantitative inner surface shape of the pipe to be inspected 1. Of course, it is also possible to infer the inner surface property of the tube 1 to be inspected based on the light quantity of the inner surface portion of the tube which is grasped from the projected image on the two-dimensional light receiving device 25.

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

The in-pipe inspection device 10 operates as follows.

First, the detection unit 12 is inserted into the inspection pipe 1. The detection unit 12 is held by wheels 16 such that the central axis of the casing 13 is substantially aligned with the central axis of the pipe 1 to be inspected.

The remote control device 11 moves the detection unit 12 to the inside of the tube 1 to be inspected by using the tube 17 and the feed wheel 18, and continuously or intermittently gives a light emission command signal to the light emission drive circuit 26 to cause the light source 21 to emit light. Let

The light from the light source 21 is condensed on the light projecting body 23 by the reflecting mirror 12, and is distributed and projected from the light projecting body 23 onto 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, and the two-dimensional light receiving device 2
Photoelectric conversion is performed at 5 and transferred to the remote control device 11 via the output circuit 30. As a result, the remote controller 11
Simultaneously obtains the detection amount from the rotation amount detector 20 of the feed wheel 18 and obtains the correlation between the output data of the two-dimensional light receiving device 25 and the sampling position (the position of the detection unit 12) of the data to be inspected. The inner surface condition at each axial position of the pipe 1 is inspected.

That is, the detection unit 12 constituting the in-pipe inspection device 10 distributes and projects the light emitted from the light source 21 by the light projecting body 23 onto the entire circumference of the inner surface of the inspected pipe 1, and the reflected light image from this is projected onto the two-dimensional light receiving device. 25 can be captured. Therefore, by moving the detection unit 12 only in the tube axis direction of the pipe 1 to be inspected under the above structure-capturing state, the state of the inner surface of the pipe 1 to be inspected can be inspected at an arbitrary position.

Here, since the in-pipe inspection apparatus 10 does not need to fill the inside of the inspected pipe 1 with water as an ultrasonic transmission medium or move the detection unit 12 by a spiral wire, the equipment can be simplified and work efficiency can be improved. Can be good. In addition, the detection unit 1
The scanning by 2 does not have a spiral shape, and the detection unit 12 can simultaneously scan the entire circumference of the inner surface of the pipe to be inspected 1, so that the inspection accuracy is also improved.

The present invention can be widely applied as an in-pipe inspection device for pipes having various sectional shapes such as a square shape.

Further, in the practice of the present invention, the detection unit may be a self-propelled type such as having a pipe moving means built therein.

[Effects of the Invention] As described above, according to the present invention, it is possible to automatically and quantitatively recognize the shape of a pipe to be inspected, and obtain an in-pipe inspection device which has a simple equipment, a high work efficiency, and a high inspection accuracy. it can.

[Brief description of drawings]

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.
FIG. 3 is a schematic diagram showing the principle of inspection of the tube surface shape, FIGS. 4 (A) and 4 (B) are schematic diagrams showing images captured by the light receiving means, and FIG. 5 is a conventional in-pipe inspection using ultrasonic waves. FIG. 6 is a schematic cross-sectional view showing the device, and FIG. 6 is a schematic cross-sectional view showing a conventional in-pipe inspection device using light. 1 ... Tube to be inspected, 10 ... In-tube inspection device, 11A ... Detection control unit, 12 ... Detection unit, 21 ... Light source, 23 ... Projector (projecting means), 25 ... Two-dimensional light receiving Device (light receiving means), 28 ... Transparent body, 29 ... Fluorescent substance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Minoru 8-1-1 Tsukaguchihonmachi, Amagasaki-shi, Hyogo Sanryu Electric Co., Ltd. Applied Equipment Research Laboratory (72) Inventor Shinichi Nagai 1-chome, Hitotsubashi, Chiyoda-ku, Tokyo No. 1-1 Toa Fuel Industry Co., Ltd. (72) Inventor Yoshiaki Taniguchi 1-3-1 Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Toa Fuel Industry Co., Ltd. (56) Reference -270600 (JP, A) JP 54-24596 (JP, A) Actually developed 55-118282 (JP, U)

Claims (1)

[Claims] 1. An in-pipe inspection apparatus for inspecting an inner surface state of a pipe to be inspected by inserting the detection unit into the pipe to be inspected and moving the pipe in an axial direction thereof, wherein an optical axis is aligned with a central axis of the detection unit. The inner surface of the tube to be inspected is the set light source and the fluorescent material dispersed and fixed in the plate-shaped transparent body, and the light emitted from the light source having a lens structure for condensing light around the plate-shaped transparent body. Has a projection means for distributing and projecting the light onto the entire circumference of the tube, a light receiving means for capturing an optical image of the inner surface of the tube to be inspected, and a detection control section for quantitatively calculating and outputting the shape of the tube to be inspected from the output of the light receiving means. An in-pipe inspection device characterized in that