JPS6358135A - Pipe inner surface measuring apparatus - Google Patents

Abstract

PURPOSE:To enable the measurement of the diameter of the inner surface of a pipe with a quick single measuring action, by projecting light emitted from a light emitting means of an optical type distance meter provided in a pig to both diametrical directions of a pipe to be measured to receive the reflected beams of light thereof. CONSTITUTION:A pig 10 is inserted into a pipe P to be measured and the center axis of the pig 10 is aligned with the axis of the pipe by making the axis center of a support rod 110 match the axis of the pipe. On the other hand, power is supplied through a cable 111 from a processor 70 and a light emitting circuit 11 activates a light emitting element 12 to emit light. The projection light from the element 12 is reflected with reflecting mirrors 41 and 42 of a reflecting mirror block 40 through a projection lens 13 to be projected outside the casing 101 through projecting windows 100a and 100b, reflected on the inner surface of the pipe P to be incident on reflecting mirrors 43 and 44 and reflected in the direction along the center axis of the casing 101 to be converged on light receiving lenses 14a and 14b, forming images on 1-D photodetectors 15a and 15b. Electrical signals specifying a photodetector where the reflected light image is formed are sent to the processor 70 from output circuits 16a and 16b to measure the inner diameter of the pipe P by processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting defects by measuring the shape of the inner surface of a tube, particularly the inner surface of a small diameter tube which cannot be visually observed.

[Prior art]

For example, inspection of the shape of the inner surface of pipes such as pipelines for transporting various raw materials and products routed within a chemical plant, or small-diameter sewer pipes that are impossible for workers to enter and directly visually inspect. A device using an optical rangefinder is known as a device for determining the presence of abnormalities such as defects and depressions.

FIG. 4 shows an example of this, in which P is a pipe to be measured, and 10 is a pig. The pig 10 is equipped with a light projection/reception window 100 made of glass or transparent resin on a part of the peripheral side wall of a cylindrical casing 101, and the center axis of the cylindrical casing 101 is aligned with the tube axis of the pipe P to be measured. They are inserted into the pipe P to be measured so that they match. Also pig 10
is located inside the casing 101 at its front end (left end in the figure).
The light emitting circuit 11. Light emitting element 12.
Light projecting lens 13° Light receiving lens 14. One-dimensional light receiving element such as a linear diode array 15. It is equipped with an output circuit 16 and the like.

The optical axis of the light projecting lens 13 is connected to a pig 10 in order to make the reflected light from the inner surface of the measurement target tube P of the projected light enter the light receiving lens 14.
The optical axis of the light-receiving lens 14 is inclined toward the rear end of the casing 101 than in the rotation radius direction, and the optical axis of the light-receiving lens 14 receives reflected light from the inner surface of the measurement target tube P of the light projected from the light-emitting lens 13. It is inclined toward the front end of the casing 10 rather than in the direction of the rotation rate of the pig 10. The light-receiving element array direction of the -dimensional light-receiving element 15 is on a plane that includes the optical axes of both lenses 13 and 14, and is perpendicular to the optical axis of the light-receiving lens 14.

Therefore, although the details will be described later, when the reflection position of the reflected light incident on the light receiving lens 14 on the inner surface of the measurement target tube P moves in the radial direction of the measurement target tube P, the imaging position of the reflected light is Since it moves in the direction in which the original light receiving elements 15 are arranged, the distance between the pig IO and the inner peripheral surface of the tube P to be measured can be determined by detecting its position.

Further, the pig 10 connects the rear end of the casing 101 to the support rod 1.
10, and is inserted through the opening of the pipe P to be measured using this support rod 110. Note that the support rod 110 is hollow, and a plurality of electric cables III connected to the processing device 70 are inserted into the hollow portion thereof, and various signals and electric energy are transmitted and received via these.

Now, in the conventional device shown in FIG. 4, power is supplied from the processing device 70 to the light emitting circuit II via the cable 111, so that the light emitting circuit 11 causes the light emitting element 12 to emit light in the direction of the projecting lens 13. Do it. This light emitting element 12
The projection light is focused by the projection lens 13, passes through the projection/reception window 100 of the casing 101, and is reflected on the inner surface of the tube P to be measured. This reflected light passes through the light emitting/receiving window 100 again, is refocused by the light receiving lens 14, and is imaged on the light receiving surface of the -dimensional light receiving element 15. An electrical signal specifying the light receiving element on which the reflected light image is formed is sent from the output circuit 16 to the processing device 70 via the cable 111.

FIG. 5 is a schematic diagram showing the principle of measurement using two devices.

In FIG. 5, the center 4 of each lens 13.14
．． Assuming that the line segment n connecting the centers A and B of both lenses 13.14 is located at the tube axis of the III constant target tube P, the angle of the optical axis of the projection lens 13 with respect to this is the distance between B. is α, and the angle of the optical axis of the light receiving lens 14 is β (=
α may be used), the light receiving element M at the center of the -dimensional light receiving element 15
(located on the optical axis of the light-receiving lens 14) to the light-receiving element R at the imaging position of the reflected light image. (the angle is constant), the reflection position of the projected light on the inner surface of the tube P to be measured is C, and the light-receiving surface of the -dimensional light-receiving element I5 is located at the focal point (focal length Mllf) of the light-receiving lens 14.

The angle θ between the optical axis of the light-receiving lens 14 and the reflected light is determined by the distance %ilIβ on the -dimensional light-receiving element 15 and the focal length f of the light-receiving lens 14 using the following formula.

"The angle between line segment B and line segment O is found as (β-θ). Therefore, triangle ABC is two angles, i.e. 1/CA
R (-α) and /CBA (-β-θ) and its flank A
Since the length d of 1 is known, it is determined. For this reason,
The length of the perpendicular drawn from point C to line segment n, that is, the distance 11 from the tube axis to the inner circumferential surface of the tube to be measured P (inner circumferential radius of the tube to be inspected P) is determined by the following formula.

tanα−jan (β±θ) Note that even if the straight line n does not coincide with the pipe axis of the pipe P to be measured, if both maintain a parallel relationship, the distance between them and the calculated distance Nh All you have to do is find the sum.

The above-mentioned principle is the same as that of bigonal survey using a line segment as a base line. In such a conventional device, the pig 10 is supported by a support rod 110 and rotated while entering the pipe P to be measured, or a self-propelled device (not shown) is used to move the pig 10 around the pipe axis as the center of rotation. The pipe to be measured P while rotating as
By moving inside, the shape of the inner circumferential surface of the pipe P to be measured can be continuously measured.

As a result, if the center of rotation of the pig 10 is correctly aligned with the pipe axis of the heir P, if the measurement result is a perfect circle, there is no defect (missing, adhesion of foreign matter, etc.) on the inner surface of the pipe. It shows that it does not. Furthermore, even if the center of rotation of the pig 10 and the axis of the pipe P to be measured do not match, if there are no defects on the inner surface of the pipe, a smooth elliptical curve can be measured. On the other hand, whether the center of the pig 10 coincides with the tube axis of the tube P to be measured or not, if a defect exists, a relatively irregular, sharp, and rapid change will be detected.

[Problem that the invention seeks to solve]

However, in the conventional pipe inner surface shape measuring apparatus as described above, it is necessary to rotate a pig within the pipe to be measured and obtain the pipe diameter from data covering the entire circumference of the pipe inner surface.

Although this method is suitable for detecting minute defects on the inner surface of the pipe to be measured, it is also useful when you simply want to know the inner diameter of the pipe, or when there is a decrease in wall thickness due to corrosion (increase in the inner diameter of the pipe).
On the other hand, when it is desired to know the decrease in the inner diameter of a pipe due to deposits, deposits, etc., there is a problem in that the measurement takes a long time and is inefficient.

Furthermore, in the conventional device described above, the cable that connects the pig and the external data processing device etc. is twisted, so in order to eliminate this twist, for example, the cable must be untwisted each time the pig rotates a predetermined number of times, or the cable that connects the pig with a predetermined It is necessary to take measures such as rotating the cable in both directions several times, and to strengthen the cable itself against damage caused by twisting. Furthermore, the use of a slip ring or the like may be considered, but this would inevitably lead to a decrease in reliability due to the complexity of the structure and the possibility of poor contact.

The present invention was made in view of these circumstances, and
The light emitted from the light emitting means of the optical distance meter provided in the pig inserted into the inside of the tube to be measured is projected onto both sides of the tube to be measured in the radial direction, and the reflected light from the inner surface of the tube is received by the light receiving means. By receiving light at
An object of the present invention is to provide a tube inner surface shape measuring device that is configured to be capable of measuring in a constant motion and capable of measuring the inner diameter of a tube to be measured without rotating a pig within the tube to be measured.

[Means for solving problems]

The tube inner surface shape measuring device of the present invention projects light emitted from the light emitting means of an optical distance meter provided in a pig inserted into the inside of the tube to be measured to both sides of the tube to be measured in the i force direction. However, a configuration is adopted in which the light reflected from the inner surface of the tube is received by a light receiving means.

(Function) In the pipe inner surface shape measuring device of the present invention, by inserting the pig with the center aligned with the pipe axis of the pipe to be measured, the inner diameter of the pipe to be measured can be measured in one measurement operation that is completed in a short time. be measured.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a side sectional view showing the structure of a first embodiment of a tube inner surface shape measuring device according to the present invention.

In the first embodiment of the pipe inner surface shape measuring device of the present invention, the light emitted from the light emitting means of the optical distance meter incorporated in the conventional device as shown in FIG. The light is projected onto both sides of the tube P to be measured in the radial direction using a mirror, and the reflected light from the inner surface of each tube is received by two independent systems of light receiving means.

In the figure, P is a pipe to be measured, and 10 is a pig. The pig 10 has a cylindrical casing 101, and is provided with light projection/reception windows 100a and 100b made of glass or transparent resin at two radially opposite positions approximately at the center in the front and back direction of the circumferential side wall of a cylindrical casing 101. The tube 101 is inserted into the pipe P to be measured so that its central axis coincides with the axis of the pipe P to be measured.

Inside the casing +01 of the pig 10, a light emitting circuit 11, a light emitting element 12. A light projecting lens 13 is provided, and the casing 10
1, a light emitting/receiving window 100a located approximately in the center in the front-rear direction;
A reflecting mirror block 40 composed of four reflecting mirrors 41 to 44 is provided at a position corresponding to 100b. The light emitting center direction of these light emitting elements 12, the optical axis of the projection lens I3, and the center line of the reflecting mirror block 40 are all aligned with the center axis of the pig 10.

Further, closer to the rear end of the reflector 40 of the pig 10, there is a light receiving lens 14a (or 14b) and a one-dimensional light receiving element 15a (or 15b) such as a linear diode array.
, an output circuit 16a (or 16b), and the like, two sets of light receiving systems as light receiving means are arranged in parallel with the central axis of the pig 10 as the center of symmetry.

By the way, the reflector block 40 is formed into a rhombus shape with one diagonal line aligned with the central axis of the pig 10 when viewed from the side. Specifically, of the four reflecting mirrors 41 to 44 forming each side in a side view, the reflection GM41.42 of two surfaces closer to the front side
The rear end of the pig 10 is expanded with the central axis of the pig 10 as a line of symmetry, and the light emitted from the light emitting element 12 and focused by the light emitting lens 13 is transmitted through the light emitting/receiving windows 100a and 100h. Through each, the light is projected toward the outside of the BIG 10 in a direction closer to the 1&end portion.

In addition, two reflecting mirrors 43 near the rear end of the reflecting mirror block 40
．． The front end of the pig 44 is expanded with the central axis of the pig 10 as a line of symmetry, and the light projected from the reflecting mirrors 41 and 42 and reflected on the inner circumferential surface of the pipe P to be measured is projected. Light is received through the light-receiving windows 100a and 100b, respectively, and projected toward light-receiving lenses 14a and 14b located near the rear end along the central axis of the pig 10.

The pig 10 is supported by a support rod 110 at one end of the casing 101, and is inserted through the opening of the pipe P to be measured using the support rod 110. Note that the support rod 110 is hollow, and a plurality of electric cables 111 connected to the processing device 70 are inserted inside the hollow portion. Various signals and electrical energy are transmitted and received through these.

Next, the operation of measuring the inner diameter of a pipe using the apparatus of the present invention will be explained.

First, the pig 10 of the apparatus of the present invention is inserted into the pipe P to be measured while being supported by the support rod 110. At this time, the support rod 110
If the axis of the pig 10 is made to coincide with the tube axis of the tube P to be measured, the central axis of the pig 10 will also coincide with the tube axis of the tube P to be measured.

Now, in the device of the present invention, there is a cable I1 from the processing device 70.
Power is supplied to the light emitting circuit 11 through the light emitting device 1, and the light emitting circuit 11 causes the light emitting element 12 to emit light in the direction of the light projecting lens 13. The projection light from the light emitting element 12 is focused by the projection lens I3, and is reflected by the two reflecting mirrors 41 and 42 near the front end of the reflecting mirror block 40 to the projection/reception window 1ota of the casing 101.

100b and is projected toward the rear end of the casing +01.

This projected light is reflected by the inner circumferential surface of the pipe P to be measured, passes through the light emitting/receiving windows 100a and 00b again, and enters the reflecting mirrors 43 and 44 at the #&shoulder ends of the reflecting mirror block 40. The light is reflected toward the rear end along the central axis of the casing 101, refocused by the light receiving lens l4a, 1411, and imaged on the light receiving surface of the -dimensional light receiving element +5a, 15h.

At this time, an electrical signal for specifying the light receiving element on which the reflected light image is formed is transmitted from each of the output circuits 16a and 16h to the cable 1.
11 to the processing device 70.

The measurement signals of the two-dimensional light receiving elements 15a and 15b obtained in the above-mentioned process are processed according to the principle shown in FIG. 5 described above. By adding these results, the inner diameter of the measurement object - WP is 1! It is self-evident that this is the case. Therefore, in the apparatus of the present invention, the inner diameter of the pipe P to be measured is measured in one extremely short measuring operation.

If it is difficult to align the center axis of the pig 10 with the tube axis of the tube P to be measured, move the pig 10 inserted into the tube P to be measured in a direction perpendicular to the tube axis within the tube P to be measured. , that is, if the measurement is carried out continuously while moving in the direction of half of the pipe P to be measured, the maximum value measured during that time will be the measured value
The inner diameter of the family head P and the 1-obtain.

FIG. 2 is a side sectional view showing the configuration of a second embodiment of the present invention.

In this embodiment, a light emitting circuit 111, a light emitting element 12. Light is emitted by the projecting lens + 3° reflecting mirror block 40 and the receiving lenses 14a and 14b, and the light is projected in two directions on the inner circumferential surface of the tube to be measured (I), and each reflected light is formed into an image. The construction is similar to the first embodiment shown in FIG. 1 in duplicate. However, there is only one one-dimensional light receiving element 15, which receives reflected light from two directions, which is imaged by both light receiving lenses 14a and 14b.

FIG. 3 is a schematic diagram showing the principle of detecting the imaging position of reflected light from two directions by the one-dimensional light receiving element 15 of the second embodiment.

Now, when the inner circumferential surface of the tube P to be measured is at the position shown by the solid line, a one-dimensional light receiving element 15 is formed by both light receiving lenses 14a and 14h for reflected light from two directions on the inner circumferential surface of the tube P to be measured. The image formation position on the second side is set as the reference position, and each time when a scanning signal is applied sequentially from the -dimensional light receiving element 15, for example, from the lower end light receiving element in FIG. The time when the light receiving element is scanned is set as LO, the time when one reference light receiving element is scanned is set as Lll, and that of the other reference light receiving element is set as t12. The image forming position on the one-dimensional light receiving element 15 of the actual reflected light from the inner surface of the tube P to be measured is determined by the peak position detection circuit 71 by sequentially applying a scanning signal to each light receiving element of the one-dimensional light receiving element 7-15. The peak level is detected at , and the time difference tl, t2 between the peak level and the scanning time of the reference position is detected at the 11.12 detection circuit 72.

The time difference between the times when these two high-level health signals are obtained from both reference positions 11. t2 is proportional to the deviations Δhl and Δh2 between the actual position of the inner surface of the pipe P to be measured (relative position to the pig 10) and the reference position. Therefore, 11. t
By detecting 2, by multiplying this by a constant which is a large value using Δh/J calculation FIPt73, Δhl
, Δh2, that is, the difference between the relative position of the inner peripheral surface of the pipe P to be measured with respect to the pig 10 and the reference position is detected.

The specific method of measuring the ratio is the same as in the first embodiment of the series, so it will be omitted.

〔effect〕

As described below, according to the device of the present invention, the inner diameter of the pipe to be measured can be measured in one measurement operation that is completed in a short time by rotating and scratching the pig inserted into the pipe to be measured. Since this is carried out, there is almost no measurement error when determining the inner diameter of the pipe, improving the reliability of the measurement and facilitating the operation, data processing, and handling of the device. . In addition, in the device of the present invention, the optical axes of the light emitting means and the light receiving means are set in the axial direction of the tube, and the reflection mirror projects the light in the radial direction of the tube to be measured, so that the pig inserted into the tube to be measured is relatively Can be formed into a small diameter. Therefore, it is possible to measure smaller diameter tubes.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 is a side sectional view showing the configuration of the first embodiment of the tube inner surface shape measuring device of the present invention, and FIG. 2 is a tube inner surface shape measuring device of the present invention. FIG. 3 is a schematic diagram showing the principle of distance measurement; FIG. 4 is a side sectional view showing the configuration of a conventional device;
FIG. 5 is a schematic diagram for explaining the measurement principle of the conventional device and the device of the present invention. ■)...Pipe to be measured 10...Pig 12...
Light-emitting element 13...Light projection lens 14...Light-receiving lens I5...-dimensional light-receiving element 41-44...Reflector Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. An optical distance meter that measures distance by receiving reflected light from the object to be measured from the light emitting means with the light receiving means is inserted into the tube to measure the shape of the inner surface of the tube. In the apparatus, a first reflecting mirror configured to project light from the light emitting means of the optical rangefinder in two directions substantially symmetrical with respect to the tube axis on the same plane including the tube axis; a second reflector that reflects the light projected by the first reflector from two directions on the inner surface of the tube toward the light receiving means;
A tube inner surface shape measuring device characterized by comprising a reflecting mirror. 2. The pipe inner surface shape measuring device according to claim 1, wherein two sets of light receiving means are provided to receive reflected light from two directions, respectively. 3. The tube inner surface shape measuring device according to claim 1, further comprising a set of light receiving means capable of simultaneously receiving reflected light from two directions.