JPH04194610A - Measuring device for wall thickness of tube-shaped material - Google Patents

Abstract

PURPOSE:To measure the wall thickness of a tube-shaped material by providing a pair of optical detectors, a distance-calculating means, a wall thickness compensation coefficient calculation means, and a compensation wall thickness calculation means. CONSTITUTION:A pair of linear beams 12 are emitted to a tube-shaped material 22 at a position of both side surfaces of a section of the tube-shaped material 22 for obtaining a value of a deviation X. Namely, a value of the deviation (x) is obtained as x=¦A-B¦/2 from linear beam light-receiving widths A and B which are detected by a pair of optical detectors 4. Then, the obtained deviation (x) is calculated by a distance calculation means 5 and a wall thickness compensation coefficient is calculated by a wall thickness compensation coefficient means 6 by using a target wall thickness of the wall thickness measuring tube-shaped material 22 and external diameter dimensions which are preset based on this x. Then, the compensated wall thickness is calculated by a compensated wall thickness calculation means 7 based on a wall thickness signal from a wall thickness detector 2 and the calculated wall thickness compensation coefficient, thus enabling an accurate wall thickness of the tube-shaped material to be measured.

Description

[Detailed description of the invention] “Industrial Application Area The present invention relates to a wall thickness measuring device for a tubular material.

[Prior art] The wall thickness of a tubular material is determined by the thickness of the core, which is more or less large or small, so even if you try to measure it using one beam of radiation, it is only necessary to irradiate the radiation in the direction. Since we don't know how, it is difficult to grasp accurately. Therefore, conventionally, a plurality of #I sources 23 irradiate radiation beams 21 shown in FIG. A parallel beam method is used to obtain the radiation beam 31 shown in FIG. A multi-beam method is used to determine wall thickness.

[Problems to be Solved by the Invention] However, all of the measuring devices used in the above-described conventional method for measuring the wall thickness of a tubular material have a problem in that the mechanism is complicated and expensive.

This invention solves the above-mentioned problems of the prior art,
It is an object of the present invention to provide a wall thickness measuring device for a tubular material that can measure the wall thickness of a tubular material using a simple detection mechanism.

[Means for Solving the Problems] A wall thickness measuring device for a tubular material according to the present invention includes a radiation irradiation means for irradiating radiation to penetrate the tubular material from the outside, and a transmission attenuation of the radiation that has passed through the tubular material. A wall thickness detector is provided on both sides of the radiation irradiation means and irradiates the tubular material with a linear beam in a direction parallel to the radiation! a pair of linear beam irradiation means; a pair of optical detectors for optically detecting the linear beams irradiated from the respective linear beam irradiation means; a distance calculation means for calculating the distance from the axis of the tube to the position irradiated with the radiation, and a wall thickness calculated from the distance signal from the distance calculation means and the preset target wall thickness and outer diameter of the tubular material. a wall thickness correction coefficient calculating means for calculating a correction coefficient; a corrected wall thickness calculating means for calculating a corrected wall thickness of the tubular material from the calculated wall thickness correction coefficient and the wall thickness signal from the wall thickness detector; This is a wall thickness measuring device for tubular materials made of.

[Function] The device for measuring the wall thickness of a tubular material according to the present invention includes a radiation irradiation means that irradiates the tubular material with radiation so as to penetrate the tubular material from the outside, and measures the transmission attenuation of the penetrating radiation to measure the thickness of the tubular material. a wall thickness detector for determining the wall thickness in the transparent portion of the material; a pair of linear beam irradiation means located on both sides of the radiation irradiation means for irradiating the tubular material with a linear beam in a direction parallel to the radiation; a pair of optical detectors for optically detecting the near beam irradiated from the linear beam irradiation means; and a position irradiated with the radiation from the axis of the tubular material based on signals from the pair of optical detectors; distance calculation means for calculating the distance to the end of the pipe; and wall thickness correction coefficient calculation means for calculating a wall thickness correction coefficient from the distance signal from the distance calculation means and the preset target wall thickness and outer diameter of the tubular material. and a corrected wall thickness calculating means for calculating the corrected wall thickness of the tubular material from the calculated wall thickness correction coefficient and the wall thickness signal from the wall thickness detector.

As shown in FIG. 5, the irradiation position of the radiation 21 is
The positions are set to be equidistant from the pair of linear beam irradiation means 23. Therefore, if the axis 0 of the tubular material 22 is on this radiation #21, the correct wall thickness t can be measured by the radiation 21.

However, if the axis 0 of the tubular material 22 is shifted by X to the left on the horizontal axis X passing through the axis 0, the wall thickness measured by the radiation 21 is (yt
It's not the correct thickness. However, in the present invention, even when measuring the wall thickness at a position off the axis, the correct wall thickness can be obtained in the following manner.

That is, (yt - yt) is as follows from the relationship shown in FIG. 5, where a is 1/2 of the outer diameter of the tubular material 22.

)'+ = (a' x!) I/l
...(1)yt=((at)-X!)I/''・
...(2) From equations (1) and (2), y, -y, = (a * x!) I /
! -((a-1)" -X!) I/1...(
3) Let α be the ratio of (yt - yt ) obtained by this formula (3) and the correct wall thickness t, then α = t/ (yt )'t ) = t/ [(a7-x) I/ goose-((a-t)'
−x” ) ”” ] ・(4) α determined by equation (4) is (yt− It can be used as a correction coefficient for (yl-y,°) corresponding to y, ) (yl can be said to be an almost unchangeable value that is uniquely determined by the roll setting).

That is, in FIG. 6, if a>t, t' and t>t' -t, line segments A, B, , line segment A*Bt and line segment A
s B * are approximately parallel to each other. Therefore, t/l' = (yt-yt)/ (yt-y*') pa・t' = t (ybyt')/ (yt-yt)=α
(y+y degree) (5) In order to find the correction coefficient α, the value of X must be known. Therefore, in the present invention, the pair of linear beams 24a and 24b are blocked by the tubular material, but in other words, the radiations A and B received by the light receiver 25 (for example, a linear array CCD camera) are The distance calculation means calculates χ by setting x=IA-Bl/2.

Then, based on this X, the wall thickness correction coefficient calculating means calculates
A wall thickness correction coefficient α is calculated, and from this wall thickness correction coefficient α and the wall thickness signal from the wall thickness detector, even if the wall thickness in the longitudinal direction of the tubular material varies, the wall thickness at the 811r plane can be calculated. It can be calculated by the corrected wall thickness calculation means.

[Example] An apparatus for measuring the wall thickness of a tubular material according to an example of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of a wall thickness measuring device for a tubular material according to an embodiment of the present invention. A wall thickness measuring device for a tubular material according to an embodiment of the present invention includes a radiation irradiation means l that irradiates the tubular material 22 with radiation 11 so as to penetrate from the outside, and measures the amount of transmission attenuation of the radiation 11 that penetrates the tubular material 22. A wall thickness detector 2 detects the wall thickness of the transparent portion of the tubular material 22, and a linear beam 1 is provided on both sides of the radiation irradiation means 1 to the tubular material 22 in a direction parallel to the radiation 11.
2, a pair of optical detectors 4 that optically detect the linear beams 12 irradiated from the respective linear beam irradiation means 3; The signal from the detector 4 causes the tubular material 2 to
a distance calculation means 5 for calculating the distance from the axis of the tube 2 to the position irradiated with the radiation 11; and a distance signal from the distance calculation means 5 and a preset target thickness and outer diameter of the tubular material 22. A wall thickness correction coefficient calculating means 6 calculates a wall thickness correction coefficient from the dimensions, and calculates the corrected wall thickness of the tubular material 22 from the calculated wall thickness correction coefficient and the wall thickness signal from the wall thickness detector 2. It is composed of a correction wall thickness calculating means 7 for calculating.

In the apparatus for measuring the wall thickness of a tubular material according to one embodiment of the present invention described above, the radiation $11 is emitted from the tubular material 2 in parallel to the linear beams 12 at a position equidistant from the pair of linear beams 12.
2 is irradiated. When measuring the wall thickness of the tubular material 22, the tubular material 22 is set so that the axis 0 of the tubular material 22 is located at the radiation line II.

However, in reality, as shown in FIG. 1, there is a high possibility that there is a deviation by X. Therefore, in the wall thickness measuring device for a tubular material according to one embodiment of the present invention, the positions of both side surfaces of the cross section of the tubular material 22 are determined by I pairs of linear beams. 2 is irradiated onto the tubular material 22 to determine the value of X. That is, from the linear beam reception widths A and B detected by the pair of optical detectors 4, the value of X is determined by setting x=lA-Bl/2. The reason why X is determined in this way is as follows. That is, if the linear beam reception width when the axis ◯ of the tubular member 22 is located at the position of the radiation 11 is C, the following relationship holds true.

A=C10X・・・・・・・・・・・・(6)B=C−x
・・・・・・・・・・・・(7) A-B=2x
;,x=(A-B)/2 However, since the axis O of the tubular member 22 may be shifted in the opposite direction to that shown in FIG. 1, x=lA-Bl/2.

The distance calculation means 5 calculates X obtained in this way,
Using the target wall thickness and outer diameter of the wall thickness measurement tubular material, which are set in advance based on this calculate.

α: j/ [(a! -x!) I/mushroom-((a-
t) '-x' ) ”' co-
(4) However, t: Target wall thickness a: 1/2 of the outer diameter dimension Then, from the wall thickness signal from the wall thickness detector 2 and the calculated wall thickness correction coefficient α, the equation (5) above is obtained. Based on this, the corrected wall thickness is calculated by the corrected wall thickness calculation means.

t'=α(y+'yt')-(5) However, t': Corrected wall thickness ylo-V*': Wall thickness corresponding to the wall thickness signal FIG. 2 shows the tubular material according to one embodiment of the present invention. This is a graph showing the average value of 354 steel pipes of the same size, measured by a constant device for the tendency of variation in wall thickness in the longitudinal direction of the same steel pipe. In this way, it is possible to easily grasp the tendency of variation in wall thickness in the longitudinal direction of steel pipes, so it is possible to easily develop countermeasures to eliminate variations in wall thickness, thereby improving the yield of steel pipes and , the quality of steel pipes can also be improved.

[Effects of the Invention] According to the present invention, the accurate wall thickness of a tubular material can be measured using an inexpensive measuring device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a wall thickness measuring device for a tubular material according to an embodiment of the present invention, FIG. 2 is a graph showing variations in wall thickness in the longitudinal direction of steel pipes, and FIGS. 3 and 4 are FIG. 5 is an explanatory diagram of a conventional wall thickness measuring device for tubular materials, and FIG. FIG. 7 is an explanatory diagram showing that α can be used as a correction coefficient. 1...Radiation irradiation means, 2...Thickness detector, 3...
・Linear beam irradiation means, 4... optical detector, 5.
...Distance calculation means, 6...Thickness correction coefficient calculation means, 7
...Correction wall thickness calculation means.

Claims (1)

[Claims] radiation irradiation means for irradiating radiation to the tubular material so as to penetrate from the outside; a wall thickness detector for measuring the transmission attenuation of the penetrating radiation to determine the wall thickness of the transparent portion of the tubular material; A pair of linear beam irradiation means that are located on both sides of the radiation irradiation means and irradiate the tubular material with linear beams in a direction parallel to the radiation, and optically detect the linear beams irradiated from the respective linear beam irradiation means. 1
a pair of optical detectors, a distance calculation means for calculating a distance from the axis of the tubular material to a position irradiated with the radiation based on signals from the pair of optical detectors; wall thickness correction coefficient calculation means for calculating a wall thickness correction coefficient from the distance signal and the preset target wall thickness and outer diameter dimension of the tubular material; A wall thickness measuring device for a tubular material, comprising a corrected wall thickness calculating means for calculating the corrected wall thickness of the tubular material from the wall thickness signal of the wall thickness signal.