JPS63243847A - In-tube inspection device - Google Patents

Abstract

PURPOSE:To obtain an inspection device which has simple facilities, high operation efficiency, and high measurement accuracy by distributing and projecting light from a light source by a 1st conic body provided in a detection head and detecting reflected light from the internal surface of a tube by a 2nd conic body. CONSTITUTION:The detection head 1 has the light source 22, projection lenses 23 and 24, a conic body 25a as a light distributing means, a lens 26 as a convergence optical system, a two-dimensional photodetection part 27, a conic body 25b, etc., in a hollow cylindrical casing 21. Then the light from the light source 22 is projected on the axial line by the lens 23 from the vertex of the conic body 25a in parallel, distributed and emitted from its peripheral surface in all directions crossing the axial line at right angles, and projected on the inner peripheral surface of the tube P to be inspected. Reflected light from the inner peripheral surface is reflected by the conic body 25b, then converged by the lens 26, and projected on the photodetection part 27. Data regarding the quantities of light of respective parts are read in a detector main body 2. Here, the conic body 25b, lens 26, and photodetection part 27 are so arranged that a reflected light image from the inner peripheral surface of the tube P to be inspected which is picked up by the lens 26 is projected on the photodetection part 27 while reduced at a necessary rate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pipe inspection device that optically detects the inner surface shape of pipes such as heat exchangers and other various types of piping, particularly the inner surface shape of small diameter pipes. .

[Prior Art] Various conventional devices for inspecting the inner surface of small-diameter pipes have been proposed, but all of them employ a configuration that uses ultrasonic waves or light, and examples thereof are shown in FIGS. It is as shown in Figure 8. FIG. 7 is a schematic cross-sectional view of a conventional tube inner surface inspection device using ultrasonic waves, showing an ultrasonic probe 42 equipped with ultrasonic transmitting and receiving functions and a reflecting member disposed opposite to the ultrasonic probe 42. 43 is inserted into the test brass pipe P, water is injected into the test brass pipe P as a transmission medium for ultrasonic waves, and the reflection member 43 is rotated around its axis. Ultrasonic waves are projected from the ultrasonic probe 42 toward this, and the ultrasonic waves are refracted at right angles by the reflecting member 43.
The ultrasonic probe 42 receives the reflected echoes from the inner and outer surfaces of the tube P to be inspected, and detects uneven deformation of the inner and outer diameters and surfaces of the tube P to be inspected. etc. are detected.

In addition, the pipe inspection device shown in FIG.
Inside, the light emitting part 52 and the light receiving part 53 face the window 51b formed in the peripheral wall thereof, and the optical axis thereof is the inner periphery of the tube P to be inspected.
Detection heads 51 are arranged so as to cross each other at the planes, and are fixed to the tip of an operating shaft 54. The operating shaft 54 rotates the detection head 51 at both ends of the tube to be inspected. The inner circumferential surface is optically inspected by driving the inner circumferential surface.

[Problems to be Solved by the Invention] By the way, in the detection device using ultrasonic waves as described above, the resolution is low due to the poor convergence property of the ultrasonic waves themselves, and the ultrasonic waves may not enter the brass pipe P under test. It is necessary to fill water as a transmission medium, and water supply and drainage equipment, as well as watertight sealing means for both ends of the pipe to be inspected, are required, resulting in high equipment costs. This method requires sealing, water supply to the inside of the brass pipe P to be inspected, and drainage work, making the work cumbersome and causing problems such as low work efficiency. -Although force-based detection devices have the advantage of not using water, they have problems such as poor work efficiency and low reliability of detection accuracy because the scanning of the inner circumferential surface of the pipe to be inspected is spiral. .

The present invention has been made in view of the above circumstances, and its purpose is to provide a pipe inspection device that has a foil-shaped facility, has high working efficiency, and has high measurement accuracy.

[Means for Solving the Problems] In the present invention, a light source and light emitted from the light source are distributed and projected over the entire circumferential surface of the inner circumferential surface of the tube to be inspected within the detection head inserted into the tube to be inspected. The apparatus includes a light receiving means and a two-dimensional light receiving section for capturing a reflected light image from the inner circumferential surface of the tube to be inspected.

[Operation] According to the present invention, it is possible to simultaneously project light over the entire circumferential surface of the inner circumferential surface of the tube to be inspected, and to simultaneously capture the reflected light image.

[Examples] The present invention will be specifically described below based on drawings showing examples thereof. FIG. 1 shows the usage Ra of the pipe inspection device according to the present invention.
! 1 is a schematic diagram showing a detection head, 2 a detection device main body, and P a tube to be inspected. The detection head 1 includes a light source 22 and first and second light projecting lenses 23 that constitute a light projecting optical system, inside a casing 21 formed in a hollow cylindrical shape with both ends closed using a corrosion-resistant material such as metal. .24, a first cone 25a constituting a light distribution means, a lens 26 constituting a condensing optical system, a two-dimensional light receiving section 27. Second cone 2
5b etc. are arranged. The casing 21 has an annular window 21a in which a transparent body is embedded in the axially intermediate peripheral wall of the casing 21 over the entire circumferential direction over a required axial direction.
It is equipped with mounting parts 21 on the outside of the front and rear end plates.
b, 21c, each of which is attached to a portion 21b.
21C, the wheels 3 are attached to one end, and three supporting rods 3a are fixed at each other end at intervals of approximately 120 degrees, and when the detection head is inserted into the brass pipe P to be tested, the gauging 21 is detected. Support the axial center line so that it approximately coincides with the axial center line of the test tube P, and while maintaining this state, test the test brass pipe P.
It is designed to allow movement inside. In addition, one end of a flexible tube 4, which also serves as an actuating body for moving the detection head 1 forward and backward, is inserted through the center of the mounting portion 21c provided on the rear end plate of the casing 21.
The other end is connected to the detection device main body 2, and a cable 22a for supplying power for each drive power, a receiving cable 29a, etc. are arranged inside. It is set up.

On the other hand, inside the casing 21, there is a first cone 2 serving as a light distribution means in the center facing the inside of the annular window 21a.
5a points its apex toward the tip side of the gauging 21,
In addition, with the axis aligned with the axis of the gauging 21, a second annular projection lens 24 is concentrically disposed on the outer periphery of the gauging 21, and the apex of the first cone 25a is A first projection lens 23 and a light source 2 are placed in front of and opposite to the
2, and on the side opposite to the apex of the cone 25a of the force cylinder 1, there is a second cone 25 whose optical axis is aligned with the axial center line of the cone 25a and whose apex is directed toward the rear end side of the casing 21. b A lens 26 and a two-dimensional light receiving section 27 are provided. As the light source 22, a laser device, an incandescent light source, or the like is used. light source 2
2 is electrically connected to the detection device body 2 via a light emission drive circuit 28 and a cable 22a, and is caused to emit light via the light emission drive circuit 28 based on a light emission command signal inputted from the detection device body 2 continuously or intermittently. The emitted light is converted into a parallel light beam by the first projection lens 23, and then projected onto the first cone 25a from its apex side in parallel to the axis. First cone 25
a has a mirror surface on its circumferential surface, and the light incident on it is distributed and radiated from the circumferential surface in all directions orthogonal to the axis, and is transmitted through the second projection lens 24 to the pipe P to be inspected. is projected toward the inner circumferential surface of the

The second light projecting lens 24 has an annular shape, and its cross section is a convex lens shape with a required circular arc on both the inner and outer circumferential surfaces,
The focal point is set to approximately coincide with the inner circumferential surface of the tube P to be inspected, and the light distributed by the first cone 25a is focused in the tube axis direction. It is designed to project a thin ring shape onto the surface. The reflected light from the inner circumferential surface of the tube P to be inspected is reflected by the second cone 25b, and then condensed by the lens 26, and the two-dimensional light receiving section 2
Projected to 7. Data regarding the amount of light received by each part thus captured is read into the main body 2 of the detection device via the output circuit 29 and cable 29a, and shape detection is performed. The second cone 25b, the lens 26, and the two-dimensional light-receiving section 27 generate a two-dimensional image of the reflected light from the inner circumferential surface of the tube to be inspected P, which is captured by the lens 26 and is scaled to a desired ratio. The mutual arrangement positions are determined so that the images are projected onto the light receiving section 27. As the two-dimensional light receiving section 27, a charge coupled device or the like is used. If a charge-coupled device is used, it may be arranged in an appropriate shape, such as a circular arrangement centered on the optical axis or a square arrangement. Figure 2 shows the axis of the tube P to be inspected and the inner circumferential surface of the tube. This is an explanatory diagram showing the relationship between the dimensions up to and the reflected light image projected onto the two-dimensional light receiving section 27, and the axial center line of the tube to be inspected P and the optical axis of the lens 26 in the detection head are now aligned. Assuming that the dimensions from the axial center line to each light reflection position Pa, Pb, and Pc on the inner circumferential surface of the tube to be inspected P are La, Lb, and Lc, respectively, the light reflected from here is reflected from the second cone. 25b and the position on the two-dimensional light receiving section 27 when reaching the two-dimensional light receiving section 27 through the lens 26 are la and lb from the optical axis of the lens 26, respectively.
, 27a, 27b, 27c separated by lc
It will be on point. The following relationship generally holds between the distances such as La, Lb, Lc, etc. and the distances l such as la, lb, lc, etc.

,... Mx *X+=□・l−-=(1) My*i:' However, D is the horizontal distance from the condenser lens to the detection surface,
F is the distance from the condenser lens to the surface of the two-dimensional light receiving section.

Here, M is the magnification of the optical system by the second cone 25b. This will be explained in detail with reference to FIG. That is, from the point of view of the lens 26, the light emitted from the point Pa is equal to the light emitted from the point Pa' by the second cone 25b. Pa' is the optical axis of the lens 26 and the second cone 25b
The 0 magnification My, which is a symmetrical position across the second cone 25b, in the Shobara system with the origin at the intersection of is Ya' My = --(2a) Ya -1------・(2b)
It becomes Ya. Here, Ya and Ya are Ya'=Xsin θ+Ycos θ ・------
(3a) Xa'=Xcos θ−Ysin θ □(3
b) However, 6 is θ=90@−(α+β)−(4) X a β=jan” Ya.

From the above relationship, the reflected light from the inner surface of the test brass pipe P projected onto the two-dimensional light receiving section 27 will be as shown in FIG. A circular image with no disturbances can be obtained, but in the areas where there is a corroded part on the inner circumferential surface of the pipe P to be inspected and it is concave, it is concave inward as shown in a in Figure 4 (b). In addition, in the convex portion due to the occurrence of casting etc., an outwardly bulging image appears as shown in b shown in FIG. 4(b). By measuring the degree of the concavities and convexities, the depth and height of the concavities and convexities can be detected. Of course, it is also possible to estimate various inner circumferential surface properties of the tube P to be inspected based on the light intensity of each part from the image projected onto the two-dimensional light receiving part 27.

However, in such an apparatus of the present invention, the detection head is inserted into the brass pipe P to be tested from the distal end side for one minute as shown in FIG. In this state, the detection head 1 is held by wheels 3 attached to its rear end so that the axis of the casing 21 approximately coincides with the axis of the tube P to be inspected. Therefore, while moving the detection head 1 within the brass pipe P to be tested using the flexible tube 4, the cable 22a is connected to the detection device main body 2.
A light emission command signal is output continuously or intermittently through the light source 22 to cause the light source 22 to emit light. The light from the light source 22 is converted into a parallel light beam by the first projecting lens 23, and the light is transmitted to the first cone 25.
The light is incident on the circumferential surface of the pipe P, is distributed and projected from there over the entire circumferential direction, is condensed by the second projection lens 24, and is projected onto the inner circumferential surface of the pipe P to be inspected so as to cover the entire circumferential direction. It is projected in a direction perpendicular to .

The reflected light from the inner circumferential surface of the tube to be inspected P is reflected by the second cone 25b.
is projected on a reduced scale through the lens 26 onto the two-dimensional light receiving section 27, photoelectrically converted in the two-dimensional light receiving section 27, taken out to the detection device main body 2 through the output circuit 29, and transmitted to the inspected tube P.
The shape of the inner peripheral surface of is detected.

Regarding the five detection methods, it is important to keep in mind that previously known methods may be selected as appropriate.

In such an embodiment, the pipe to be inspected P is
It is possible to simultaneously project light over the entire circumferential surface of the inner circumferential surface of the sensor and capture the reflected light from the inner circumferential surface of the sensor.There is no risk of detection failure, and the detection accuracy is high.
High reliability can be obtained.

In addition, in the above-mentioned embodiment, the case where both the pipe to be inspected P and the casing 21 of the detection head 1 are circular has been described, but the present invention is not limited to circular shapes and can be applied to various shapes of pipes.

Furthermore, in each of the above-mentioned embodiments, the detection head 1 is propelled inside the brass pipe P to be tested by inserting or pulling out the tube 4. Needless to say, it's a good thing.

Further, in the above embodiment, the first and second light projecting lenses 23,
24, but this is possible if the first projection lens 23 is configured to condense the luminous flux emitted from the light source 2 onto the inner circumferential surface of the test target P. The optical lens 24 becomes unnecessary.

Furthermore, in the above-mentioned embodiment, an example was shown in which the optical section in the detection head 1 was configured independently, but the first and second conical bodies 25a
, 25b may be integrated, or the projector and light receiver may be constructed in one piece as shown in FIG.

FIG. 6 shows the optical part of the device according to another embodiment. In the same figure, 25c is a third cone which is hollow and has a conical inner surface, and the apex of the cone is not shown, but the optical axis of the lens 26. above, and the axis of the cone coincides with the optical axis. In other words, in a configuration where there are 0 third cones 25c surrounding the second cones 25b,
The reflected light from the tube P to be inspected is reflected by the third cone 25c, then reflected again by the second cone 25b, and enters the lens 26. The position 1 of the reflected light projected onto the two-dimensional light receiving section 27 is as in the case of the above-mentioned device.
It is proportional to the position of the tube P to be inspected. However, due to the effect of the third cone, the magnification of the optical system changes considerably, and in this apparatus, the position of the tube to be inspected P and the projection position l of the reflected light are directly proportional.

[Effects] As described above, according to the present invention, the light distribution and projection means simultaneously projects light onto the inner circumferential surface of the tube to be inspected so as to cover the entire circumferential direction of the tube, and the reflected light from this is captured at the same time, so that there are no undetected areas. The present invention has excellent effects such as there is no risk of occurrence, there is no positional shift in the tube axis direction, the reliability of shape detection accuracy is high, and the equipment is simplified and the equipment cost is low. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the device of the present invention, FIG.
Figure 3 is an explanatory diagram showing the principle of detecting the shape of the inner surface of a tube, and Figure 4 (
A) and (B) are explanatory diagrams of the inner circumferential surface of the tube to be inspected captured by a light receiving element, FIGS. 5 and 6 are configuration diagrams explaining other embodiments of the present invention, and FIGS. The figure is a schematic cross-sectional view of a conventional device. 1-m-detection head 2-111 detection device main body 3--
Wheel 21 □Tacing n □-Light source O □First light projection lens 25a □
・First cone 25b--Second cone 25cm-Third cone 3-1111 Condenser lens I □Two-dimensional light receiving section 3・
-1 light emission drive circuit □Output circuit P---1 tube to be inspected 100 □Light projecting means 101 -m-Light receiving means Note that in the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) In a device that detects the inner surface shape of a tube to be inspected by inserting a detection head movable in the axial direction into the tube to be inspected, the detection head includes a light source and a light source that transmits light emitted from the light source into the tube to be inspected. a light projecting means consisting of a first cone and a light projecting lens that distributes and projects the light over the entire circumferential surface toward the inner circumferential surface of the pipe to be inspected; 1. A pipe inspection device comprising: a light-receiving means comprising a cone; and a two-dimensional light-receiving section that generates an electric signal corresponding to the reflected light image. (2) The pipe inspection device according to claim 1, wherein lenses and cones necessary for each of the light projecting means and the light receiving means are integrally molded.