JPS6044602B2 - Method for measuring tube wall thickness of tubular materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for measuring the wall thickness of a tubular material, which can simultaneously measure the wall thickness of a tubular material at multiple points around the tubular material in a non-contact manner.

FIG. 1 is a conceptual diagram illustrating the principle of a method for measuring the wall thickness of a tubular material proposed by the present inventors and filed separately by the present applicant (Japanese Patent Application No. 54-12264).

In the same figure, tubular material 2? , the thickness dimensions of each tube wall at points A, B, and C, which equally divide the tube circumference into Ξ, are x, x. and X. shall be determined by measurement. A radiation source 1 that emits a measurement radiation beam 3, a radiation source container 2 that accommodates the measurement radiation beam 3 and directs the radiation beam 3 in a predetermined direction, and a tubular material 20 corresponding to each of points A to C. A measurement system consisting of a detector 4 for detecting the radiation beam transmitted through the tube wall is provided.

Each code numeral is suffixed with the letter A, B or C denoting the measuring system to which it belongs. Note that the detection outputs of the beam transmitted through the tube wall by the detectors 4A to 4C are 11 to 13, and the detection outputs when the tube wall does not exist (that is, when the beam is directly input) are 110 and 120, respectively.
and 130. The arrangement of each measurement system is as shown in Figure 1, and one radiation beam passes through two measurement points. Two transmitted beams are configured to pass through the measurement point. Now, in Fig. 1, the output 1 of the detector 4 and the thickness dimension of the tube wall X
The following relational expression holds true as a basic equation for a general radiographic thickness gauge.

However, P is the absorption coefficient of the radiation used for the tube wall material, and k is the actual passage length S (see Figure 1A) of the radiation beam passing through the measurement point on the tube wall, and the thickness of the tube wall at that point. It is the number divided by x.

If the angle θ between the radiation beam transmission direction and the diameter direction of the tubular material at the measurement point is zero, k is 1. By selecting the number of measurement points, the width of the radiation beam, the radiation transmission method, etc. according to the shape of the tubular material, k can be made a constant that is not affected by unevenness in the thickness of the tube wall. Now, if the above-mentioned equations (1) to (3) are considered as simultaneous equations and the solution thereof is found, the result is as follows.

Therefore, the detector outputs 110, 11, 12 of the radiation beam
0, 12, 130, 13 and constants P and k, the tube wall thicknesses Xl, X2 and X3 can be calculated by calculation.

Although the above explanation was based on the case where there were three measurement points, the above-mentioned measurement method can generally be extended to the case where there are n measurement points. Let the tube wall thickness at n measurement points be Xl, X2
, . Note that the following relational expressions are obtained by logarithmically transforming the above-mentioned equations (1) to (3). The above formula (
7) When expressed using a matrix, it becomes as follows.

However, n is an odd number.

FIG. 2 shows a modification of the measurement method described above, that is, n
FIG. 3 is a conceptual diagram showing a method in the case of =9.

In this case, the thickness dimensions Xl, X2,... at each measurement point
・! It will be clear in light of the above equation (7a) that the simultaneous equations for determining the equations are expressed by the following matrix.
FIG. 3 is a conceptual diagram showing another modification in the case where n=9.

Compared to the case of FIG. 2, the number of measurement points is the same, but the positions of the measurement points through which the radiation beam passes are different. That is, in Fig. 2, the combinations of the positions through which the beam passes are X1 and the formula, X2 and X3, X3 and Xl, X4 and X5, etc., but in Fig. 3)
9X3, X69X4, X7, etc. Therefore, if the simultaneous equations are expressed as a matrix, it becomes as follows. The above equation (9) can be rewritten and expressed as the following equation (IQ).

As is clear from the above (Equation 10), the modified I in Figure 3 is
It can be said that this is nothing but a method in which the three-point measurement method shown in Fig. 1 is carried out in three cases.

FIG. 4 is a conceptual diagram showing yet another modification in the case where n=9.

In other words, the combination of the positions where the beam passes is X1 and X
6, X2 and X7, X3 and X8, X4 and X9, X5 and Xl
, X6 and X2, X7 and X3, X8 and Xl, and X9 are like a sword. The simultaneous equations in this case can be expressed as a matrix as follows.

FIG. 5 is a conceptual diagram showing an example where n=8.

In this case, for an appropriate odd number m (5 in this example) among the n even number of measurement points, a simultaneous equation of Saw is established based on the output value of the measurement system, and each Find the thickness dimension. Next, the thickness of the unknown measurement point is determined by measuring the intensity of the beam that passes through one of the m measurement points whose thickness has been determined and the unknown measurement point. Of course, the least squares method may be used. This will be explained in detail with reference to FIG.

Since n=8, the thickness of each measurement point is Xl, X2...
...? shall be. First, five of the eight measurement points are selected, and the thickness dimensions Xl, X3, X4, X6, and X7 of the selected points are first determined. It will be easily understood from the previous explanation that the simultaneous equations are obtained as follows.
However, when measuring X3 and X7, k=1 according to the definition of k described above, so only in this case, 1 is substituted for 5k. Solve the above simultaneous equations to obtain the following solution. The unknown dimensions are X5, X8, and X2.

Therefore, a radiation beam is transmitted through each combination of X5 and Xl, X8 and Xl, and X2 and X6 to obtain the following equation. In addition, X
In the case of 1 and 抛, k=1 as well.

Since X1 is known, the yoke can be found from the above equation.

similarly In this case too, k=1.

In this case, k=1 as well.

Since Xl and XG are each known, X8 and X2 can be determined from the above equations.

Before describing the problems of the conventional technology as outlined above, let us return to the principles of the vibrator tube wall thickness measurement technology and consider the basics.

(1) Regarding the cross-sectional shape of the vibrator, the measuring method according to the present invention is applicable to the cross-sectional shape. is a vibrator with a circular shape.

However, as will be described later, the present invention can also be applied to a vibrator whose cross-sectional shape is a regular (2m+1) polygon (however, m=1, 2, 3...), and a circular cross-section is , positive (
2rT1+1) polygon, it is considered to correspond to the shape when m is set to an infinite or infinite value. The circular cross section of the vibrator is considered on a measurement plane that crosses the vibrator (a plane on which a measurement system consisting of a radiation source and a radiation detector is arranged).

FIG. 6 is a perspective view defining the cross section of the vibrator. As shown in the figure, a cross section 6 obtained by cutting the vibrator 20 along the measurement plane 5 is defined as a cross section of the vibrator to be measured. The plane 5 is, for example, a plane perpendicular to the line center of the vibrator production line, and can be set at any angle as necessary. As shown in FIG. 6, when the vibrator 20 is curved, it is preferable to set the cross section at a position where the roundness of the cross section to be measured is highest in the curved portion. The vibrator whose wall thickness is measured by applying this invention is a vibrator having a certain degree of high roundness.

To be specific, in the vibrator cross section shown in Fig. 7,
A radius R between the outer wall 7-1 of the vibrator, which has a certain degree of unevenness, and the inner wall 7-2, which also has unevenness. It is necessary to have a degree of roundness that allows the virtual perfect circle 7-3 to be drawn without failure. As shown in Fig. 8, when considering polar coordinates r=r(θ) whose origin is between arbitrary points in the cross section of the vibrator, a complex cross-sectional shape in which the inner wall or outer wall dimensions are multivalued functions is It is not applicable to the measurement method according to the invention. In FIG. 8, when r is the outer wall dimension from the origin i, the value of r(θ1) is the distance from the origin n to the point 8-1, and the distance from the origin to the point 8-2. It can take two values (bivalent function) and represents a complex cross-sectional shape. However, as shown in FIG. 9, the vibrator has a partial cutout 9-1 in the cross section, and as shown in FIG.
-1 or a vibrator with micro grooves 10-2,
It is possible to apply the measurement method according to the invention.
That is, in FIG. 10, the wall thickness of the vibrator is determined as an average wall thickness within a certain resolution W range, and
Since the shapes of protrusions and grooves are not measured, the measuring method according to the present invention can be applied. )) Definition of wall thickness dimension For a cross section of a vibrator that has a high roundness to the extent that a virtual perfect circle can be drawn without failure in the thick area between the outer and inner walls of the vibrator, the center is defined as follows.

The center of the cross section of the vibrator may be the center of gravity of the vibrator, or it may be the intersection of the center lines 11-1 and 11-2 of the outer diameter measured from two different directions, as shown in FIG. good. Alternatively, in the vibrator manufacturing line, if the vibration phenomenon in which the vibrator is conveyed is suppressed by some means (for example, pinch rolls, etc.), the center of the various pipe-making machines or the center of the conveyance line The center of the vibration may be considered to be the center of the vibration, and the center of the line may be considered to be the center of the vibration. As mentioned above, once the center n is determined according to a certain definition (the definition of the center is not specific, the center position will differ depending on the definition), then the wall thickness can be defined. I can do it.

Please refer to FIG. A line segment NA is drawn in the radial direction from between the vibrator centers, and the wall thickness dimension along this line segment '0A is defined as the wall thickness dimension X1 at measurement point 1. However, it is assumed that the measurement point 1 is one point within the thick region on the line segment A, and is the point where the radiation beams 3A and 3B intersect. In addition, the wall thickness dimension X1 is the average wall thickness dimension value (the average means an arithmetic mean) in a certain range W on the outer wall or a certain range W2 on the inner wall centered on the line segment HA. ). The range W1 is the area between the points where the beams 3A and 3B intersect with the outer wall of the vibrator, and the range W2
is also the area between the points where the beam intersects the inner wall. W1 and W2 will be described later. (3) Modeling of the Vibrator Cross Section So far, it has been explained how to select the vibrator measurement cross section, that the object of the measurement method according to the present invention is a vibrator with a predetermined circular cross section, the definition of the center of the cross section,
We have explained the definition of wall thickness dimensions, etc.

The vibrator cross section can be modeled based on these explanations. In Fig. 12, the measurement point is set to 1, and the outer radius is constant at RlP in the area W1 on the outer wall, and the inner radius is R in the area W2 on the inner wall.
It is assumed to be constant at 2Pl. That is, if the thickness of measurement point 1 is to be measured at resolution W1 or W2, then the first
The dimensional relationship of the vibrator wall thickness shown in FIG. 2 can be modeled and considered as shown in FIG. 12A. Furthermore, the 12th
In the figure, ξ51 indicates the thickness in the diagonal direction along the beam 3A, and ξB2 indicates the thickness in the diagonal direction along the beam 3B. As a multi-point thickness measurement method around the vibrator, considering the case of three-point measurement with the smallest number of measurement points, Fig. 12 and 12A
As shown in the figure, modeling for one measurement point is done in three ways.
By expanding the equation to points, a model as shown in FIG. 13 can be obtained.

In Fig. 13, the darkness is the center of the vibrator, RlRl is the outer radius of measuring part 1, R2Pl is the inner radius, RlP2 is the outer radius of measuring part 2, R2P9 is the inner radius, and RlP3 is the outer radius of measuring part 3. , R2P3 indicate the same inner radius, and all the circles having the above radii are concentric true circles centered at the center.

Now, based on the above basic considerations, the problems of the prior art will be explained below.

In the prior art (specifically, the method for measuring the wall thickness of a tubular material proposed in Japanese Patent Application No. 54-12264), with regard to FIG. Ratio to X, k=? It is possible to know this in advance.

However, strictly speaking, it is not easy to know this accurately in advance. In special cases where the range of variation in the wall area of the outer diameter and inner diameter is small, k may be known in advance using an approximate method, but generally, theoretically, k cannot be determined accurately. You can't ask for it. This will be explained next. Please refer to FIG.

Draw a line segment NA in the radial direction from the center b of the vibrator. X is the wall thickness of the vibrator along line segment 0A, ξ is the diagonal wall thickness along straight line 1 that forms an angle 0 with line segment '0A and intersects line segment ()A at measurement point B, and R1 is the outer wall thickness. radius, R2 is the inner radius, RO is the radius of a virtual perfect circle passing through measurement point B, h is the straight line 1 from the center point σ
It is the length of the perpendicular line. Then, the following formula holds true. In the above formula, 0 is known and point B can be arbitrarily selected, so the dimension R.

is also known. From equation (A-1), it can be seen that the diagonal wall thickness ξ can be determined only after the outer radius R1 and the inner radius R2 are divided. If we rewrite this equation as equation (A-2), we get this (
From formula A-2), it can be seen that the relationship between ξ and x becomes clear only when the outer radius R1 and wall thickness x become clear. That is, it can be said that, generally and theoretically, k, which is the ratio between ξ and x, cannot be determined. However, when the outer diameter and inner diameter are relatively constant around the vibrator, k can be approximately determined by the following method.

(1) A method of calculating in advance from the above formula (A-2) using the nominal outer diameter and nominal inner diameter of the vibrator.

(Ii) Similarly, a method in which the nominal outer diameter dimension and nominal inner diameter dimension are experimentally determined by prior measurement using an accurately produced standard sample.

(111) As shown later, approximately t'. A method of calculating as COsθ.

The present invention was made in view of the technical circumstances related to the prior art as described above, and therefore, the purpose of the present invention is to provide a vibrator that has relatively large local variations in outer diameter and wall thickness. It is an object of the present invention to provide a method for measuring the wall thickness of a tubular material, which can theoretically and accurately determine the wall thickness at a point selected as a measurement point.

The gist of this invention is to assume a regular-odd polygon whose origin is the center point of the cross section of the vibrator, with the apexes of the polygon located within the thick wall region, and to set each apex as a measurement point. A radiation beam is emitted from the peripheral direction of the vibrator in the direction along each side of the vibrator, passes through the measuring point, measures the beam intensity after passing through, and calculates the vibrator wall thickness at each measuring point by calculation based on the measured value. The reason lies in the fact that the dimensions are determined.

Next, embodiments of the present invention will be described with reference to the drawings. [1st
Example] First, an example will be described in which a three-point wall thickness method, which is the minimum number of points in multi-point measurement, is performed.

Now, as shown in FIG. 15, it is assumed that measurements are taken at three points (measuring sections 1 to 3) on a certain cross section of the vibrator 20. The distance between the center points is determined by an arbitrary definition as described above. An enlarged view of the measuring section 1 in FIG.
Assume that the situation is as shown in FIG. FIG. 12 shows the measurement part 1 of the vibrator by an average (not an arithmetic average) outer diameter dimension RlPl centered between the points and an average inner radius R2Pl also centered around the point σ. Fig. 12A shows this as a model.

Furthermore, the same can be said about measuring parts 2 and 3 in Fig. 15, so in the end, the 3rd part of the vibrator cross section as shown in Fig. 15.
It can be said that point measurement is attributable to measurement of a model of a combination of concentric circular arcs as shown in FIG.
FIG. 16 is a conceptual diagram showing a measurement system for implementing the present invention. Although it appears to be the same at first glance as the measurement system according to the prior art shown in FIG. They differ in this respect.

(b) The point between is the center point of the measurement system.

In other words, the center point of a virtual perfect circle 13-1 on which the beam intersections 1, 2, and 3 are placed on the circumference is h'', and the radius of the perfect circle is R. (B) Point 1 , 2, 3 as vertices are equilateral triangles.

In other words, all angles seen from the center point to each vertex are equal,
The following formula holds. (c) A virtual perfect circle 13-1 is assumed.

This perfect circle R. There are various ways to determine the radius of . For example, it may be determined according to the following equation (A-4). Here, Rlm is the expected average outer radius dimension of the vibrator to be measured, and R2m is the inner radius dimension as well.

Alternatively, it may be determined as in the following equation (A-5). Or can it be determined as in the following formula (A-6)? Wear.

These are the above-mentioned constraint conditions for the three fish.

1. When carrying out the measurement method according to the present invention,
The center σ of the measurement system in FIG. 16 is arranged to coincide with the center distance of the vibrator cross section in FIG. 15. Alternatively, the distance 6y between b and σ is sufficiently small and satisfies the following condition. Hereinafter, in order to simplify the explanation, the explanation will be made assuming that the intermediate point and the i'' point coincide.In this way, the measurement system shown in FIG. 17 is realized.5 Next, for the sake of explanation, the measurement Let us explain the resolution at a point. The vicinity of measurement point 1 in Fig. 17 is enlarged and shown in Figs. 18 and 19. In Fig. 18, O is the center of the vibrator cross section, and the center of the measurement system matches.Rl.n
is the average outer radius dimension and 1. ri, R2. is the inner radius dimension. RO is the radius of a virtual perfect circle on the circumference of which the intersection of the beams is placed. Wlm) Beams 3A and 3B are respectively
It is the distance between the points that intersect with the circle with radius Rlm, and Wlj,φ
1 ・Ri,. ．． It is expressed as However, φ1 is the center point b
Distance W, . There is a corner overlooking 1. W2. is beam 3
This is the distance between the points where A and 3B each intersect with the circle of radius R6. And it is expressed as W2n,=φ2·R6. It goes without saying that the angle φ2 is an angle at which a distance W2n is desired from the center points. In FIG. 18, since φ2>φ1, the larger φ2 is adopted as the resolution of measurement point 1. In other words, the resolution of the measurement point is defined as φ=φ2 for angle φ2 and W=φ·RO for distance W. In Fig. 19, since φ1>φ2, 2φ1 is adopted, and as the resolution, for the angle φ, φ=φ1, and for the distance W, W=
It becomes φ・RO.

In the measurement system shown in FIG. 17, the resolution of the measurement point is φ in angle and W in distance. That is, in the measurement system implementing this invention, within the range of angle φ! This is to measure the average wall thickness. In other words, the measurement is performed assuming that the wall thickness is constant within the range of the angle φ, or that the outer radius and inner radius are constant. Considering the resolution φ (or W) in this way, the measurement system shown in Fig. 17 is shown in Fig. 20. be recognized as such. That is, FIG. 20 corresponds to FIG. 13 and FIG. 16 superimposed. In Fig. 20, the diagonal wall thickness of the measurement part 1 along the beam 3A is ξ151.
2. The same thickness of the measurement part 2 is ξ2b12, the diagonal thickness of the measurement part 2 along the beam 3C is ξ2, 23, the same thickness of the measurement part 3 is ξ3, 23, the diagonal thickness of the measurement part 3 along the beam 3 is Let the wall thickness of
31, the quantities measured by the principle of the transmission type radiation thickness meter are the three quantities Dl2, d23, and d3l in the following equation.

, the above equation (A-8) cannot be solved because there are six unknowns such as ξ1512, ξ2512, . . . ξ1, 31 for three equations. However, in the case of the measurement method according to the present invention, the following conditions exist.

(1) Since the beam intersections 1, 2, and 3 form an equilateral triangle, the angle θ1b between the radial directions 0, 1 and the beam 3A
, 2, the angle θ1b between the radial direction 0, 1 and the beam 3B
It is equal to 31.

(Ii) Measurement is performed at resolution φ.

That is, the average thickness within the range of the angle φ desired from the center point toward the wall of the vibrator is measured. Based on the above two conditions, the following equation holds true. Above (A-8), (A-
9), the following equation is obtained.
) This can be expressed as a matrix as follows.

The above formula (A-10) can be solved as follows.

That is, by setting the beam arrangement in the cross section of the vibrator to be an equilateral triangle, the diagonal wall thickness dimensions ξ1, ξ2, and ξ3 measured at the resolution φ can be theoretically determined accurately and easily.

Although the degree of wall thickness deviation around the vibrator can be determined by measuring the wall thickness in the diagonal direction, it is also possible to determine the wall thickness distribution around the vibrator by converting this into the wall thickness dimension in the radial direction. If you want to do so, you can use the following two conditions.

(1) First, in the case of seamless steel pipes, which are the main target of the measurement method according to the present invention, for example, JIS 3439 (1)
977) The tolerance ranges for the outside diameter, thickness, and weight of the vibrator in Table 7 for seamless steel pipes for oil wells are as follows.

As is clear from the excerpt above, it is relatively easy to manufacture seamless steel pipes for oil wells with good roundness in the outer diameter, but it is relatively difficult to reduce unevenness in wall thickness. .

Because of these circumstances, in a seamless steel pipe, even if the outer diameter dimension R1 is constant and known, a large error will not occur. (Ii) The following equation can be obtained by transforming equation (A-2) described above.

Here, RO and θ are known, ξ is known from equation (A-12), and R1 is known from the above condition (1), so the equation (
Solving A-13) for X results in the following.

It will be understood that the radial wall thickness x of the vibrator is uniquely expressed using the wall thickness dimension ξ in the diagonal direction forming an angle of 0 according to the Nokami equation.

That is, it has been understood that in the embodiment of the present invention, the beam arrangement 3 is made into an equilateral triangle, and the radial thicknesses Xl, X2, and X3 can be determined theoretically correctly with the resolution φ.

However, in this case, 0 is given by the following equation. [Second Example] The first example was about a method of measuring wall thickness at three points around the vibrator.

It is easy to extend this to the case of multi-point measurement of three or more points. In FIG. 20, one of the constituent features of the present invention is that the angles θ1b12 and θ1b31 formed by the two beams passing through the measurement point 1 with respect to the radial straight lines '0 and 1 are equal. At all measurement points, in order to make the angles that the two beams passing through the measurement point make with respect to the radial line segment passing through the measurement point equal, a regular (21T1+1) polygon (where m= 1, 2, 3...
...) should be selected as measurement point 1. That is,
In the case of five-point measurement in which m=2 and each vertex of a regular pentagon is used as a measurement point, two types of measurement methods shown in FIG. In both figures, the beam intersection point 1 on a virtual perfect circle in the vibrator wall thickness area is
4, 2, 5, and 3 form the vertices of a regular pentagon.

In the case of Fig. 21A, the diagonal thickness dimensions along the beam direction at each measurement point are ξ1, ξ2, ξ4, ξ5, and the quantities related to the beam intensity after passing through the measurement point are Dl2, d23,
If d34, d45, (151), the following relational expression holds true. By solving the above equation, the diagonal wall thickness ξ1, ξ of each measurement point can be obtained.
2...ξ5 can be obtained respectively. In this case, θ = "L = mutual, so use this 2
×510, the radial thickness can be determined from the diagonal thickness and the radial thickness.

In the case of the opening in FIG. 21, the following equation holds true in the same way.

However, Dl4 is a quantity related to the radiation beam intensity after passing through measurement points 1 and 4, and D25 is a quantity related to the beam intensity after passing through measurement points 2 and 5, and the same applies hereinafter. . Equation (A-17) can also be written as follows.

The above equation (A-18) is an equation of the same form as the equation (A-16), and can be solved in exactly the same way.

However, θ=)W. FIGS. 22A, 22B and 22C are explanatory diagrams of an embodiment in the case of seven-point measurement according to the present invention.

That is, this corresponds to the case of a regular (2111+1) polygon where m=3. Polygons 1, 6, 4, 2, in Figure 22 A
7, 5, 3 and polygons 1, 5, 2, 6 at the entrance of Figure 22
, 3, 7, 4 and polygons 1, 2, 3, in Figure 22 C.
4, 5, 6, and 7 form a regular heptagon on a virtual perfect circle (radius R) in the thick region of the vibrator. The diagonal wall thickness along the beam direction at each measurement point is ξ1, ξ2, ξ
3,...ξ7, the measured quantity related to the beam intensity after passing through measurement points 1 and 2 is Dl2, the measured quantity related to the beam intensity after passing through measurement points 2 and 3 is D23, and so on. The following equation holds true. However, it goes without saying that the thickness of the vibrator in the radial direction can be determined by calculation in Figure 22 A, Figure 22 Opening, and Figure 22 C.

Now, the cases of three-point measurement and five-point measurement have been described above, but in general, the present invention can be extended to (2n1+1) point measurement. However, m=1, 2, . . . On the virtual perfect circle in the vibrator wall thickness region, (2rT
Assuming a regular (2rn+1) polygon having 1+1) vertices and using each vertex as a measurement point, the following general equation holds true. However, ξ is a general expression of the diagonal wall thickness in the beam direction at each measurement point, and d is a general expression of the measured quantity related to the beam intensity transmitted through any two measurement points. It is. In the case of 2(m+1) point measurement, m different measurement systems can be realized by selecting two points through which the beam passes.

Incidentally, in the case of 3-point measurement (m = 1), there is one measurement system, in the case of 5-point measurement (m = 2), there are 2 methods, and in the case of 7-point measurement (m13), there are 3 methods. It was hot. Furthermore, the angle 0 that a beam passing through a measurement point makes with respect to a line segment connecting the measurement point and the vibrator center point is generally given by the following equation.

However, n = addition + 1, i = 1, 2, 3, ... m order, generally speaking, when considering n-point measurement, when n consists of a prime number α, that is, n = If α and β can be written,
It is clear that m-point measurements can be realized by combining α-point measurements in β ways.

This will become clear by referring to FIG. [3rd
Example] Next, consider a case where the object to be measured is a vibrator having an odd square shape.

Referring to Figure 23, the outer wall is ΔN°C and the inner wall is ΔA″B.
A triangular vibrator consisting of a "C" is shown.

The thickness of each side is assumed to be Xl, X2, and X3. now,
In the thick region of the triangular vibrator, a virtual equilateral triangle A
Considering ``'', B'''', and C'', let the legs of the perpendicular line drawn from the center of ΔA'', B'', and C'' to each side be points 1, 2, and 3, and use these points as measurement points. . Beams B-1-2, B-2-3, and B-3-1 are passed through each measurement point as shown. The diagonal wall thickness in the beam direction at points 1, 2, and 3 is ξ1,
ξ2 and ξ3, and the measured quantity related to the beam intensity after passing through points 1 and 2 is Dl. , D23 after passing through points 2 and 3
, the following equation holds true if the point 3,1 after passing through is D3l. , after solving the above equation and finding ξ1, ξ2, ξ3, x=ξCOs
The wall thickness dimension X of each side of the triangular vibrator can be determined from the relational expression θ. The embodiments described above for triangular vibes can be extended to the case of odd square vibes.

Please refer to FIG. 24. Figure A, C] In this case, the outer wall is at point A.
, B, C, D, El inner wall is at point A″, B″, C″, D″,
A pentagonal vibrator consisting of E'' is shown.A regular pentagon with vertices A'', B'', C'', D'', and E'' is assumed in the thick area of the vibrator, and the distance between the centers of the pentagon is Let the legs of the perpendicular line drawn down from to each side be 1, 2, 3, 4, and 5, and use these points as measurement points. It will be understood that this embodiment is ultimately the same as the case of the mouth in FIG. 21 described above. In addition, the example of a pentagon can be expressed as positive (2rT1+
1) It is obvious that it can be extended to square-shaped vibes without any need for explanation. Here, the limit when m is set to infinity corresponds to a circular vibrator. Therefore, in the case of a circular shape, all odd numbers are prime numbers, so multi-point (odd point) measurement is possible for all odd numbers. A more general case of odd-numbered vibration is shown in FIG. 24, and the equation for that case is shown below.

[Fourth Embodiment] In the explanation so far, it has been explained that an ideal line beam is used in the measurement, but in reality, for a given outer radius R1 of the vibrator, a line beam and an ideal line beam are used. It is often difficult to achieve a beam that is appreciably narrow.

Therefore, again taking the case of three-point measurement as an example, an embodiment in which measurement is performed using a beam with a width will be described. FIG. 25 is a conceptual diagram showing such an embodiment. Refer to FIG. 25.

In the figure, the radiation from the radiation source S-1-2 is focused by the collimator SCl-1-2 and DCl-1-2, and finally becomes a beam with a width d, which is delivered to the detector D-1-2. reach. The same applies to the remaining two measurement systems, namely, the measurement system consisting of the radiation source S-2-3 and the detector D-2-3, and the measurement system consisting of the radiation source S-3-1 and the detector D-3-1. be. At that time, the center line of beam B-1-2? -1-2 and beam B
-2-3 center line 0-2-3 and beam B-3-1 center line? According to the present invention, points 1, 2, and 3 where system is placed. At this time, FIGS. 26 and 27, which correspond to FIGS. 18 and 19 described above, are drawn and referred to.

26 and 27 are enlarged explanatory views of the vicinity of the measurement point in FIG. 25, respectively. In these figures, the resolution φ(
Expressed in terms of distance, considering W=φ·RO), it can be seen that the resolution is greater than in the case of a line beam by the width of the beam. At this time, the area of the part where the beam B-1-2 passes through the thick region and the area of the part where the beam B-3-1 passes are equal, as shown in the shaded area in FIG. The outputs obtained by detecting each of the beams are equal, which also means that the measured diagonal wall thickness along the direction of beams B-1-2 and the measured diagonal wall thickness along beam B-3-1 are equal. This indicates that the dimensions are the same. This also applies to other measurement points. Therefore, the diagonal wall thickness along the beam direction at each measurement point measured using a wide beam is rewritten as ξ1, ξ2, ξ
3, these can be determined in exactly the same way as for the line beam. Now, in Fig. 28, assuming that the average thickness ξ1 in the O direction over the range of the beam width d (although it is called an average, it is not an arithmetic mean) ξ1 is found, how to convert this to the thickness X1 in the radial direction? You can do it like this:
(1) The above equation (A-15) is used approximately, ignoring the beam width.

(Ii) When the degree of approximation of the values obtained by the method (1) above is low, it is better to use the so-called comparative calibration method.

That is, a large number of sample data with different outer diameter dimensions and wall thickness dimensions are prepared for perfect circular vibrators, and the following matrix table is created. In Table 1, the outer radius and wall thickness are sample data for calibration and are known. Table 1 is created by measuring a large number of diagonal wall thicknesses ξ corresponding to these using the method of the present invention. Next, Table 1 above
Rewrite and create the following Table 2. Of course, methods such as interpolation are also used as necessary. Once Table 2 is obtained, the radial wall thickness X can be easily determined from the measured diagonal wall thickness ξ and the outer radius dimension using Table 2. (11i) Above (1)
A method in which the radial wall thickness is determined using the first approximation method, and the amount of error is determined using the comparative calibration method.

In addition, there are various methods.

If the beam has a width, it will be readily apparent that the three-point measurement example described above can be extended to measurements at an odd number of points, such as five or seven points, as in the case of a line beam. [Fifth Example] Refer to FIG. 29.

This figure schematically shows the components of a measurement system when the present invention is implemented in combination with an outer radius meter that instantaneously measures the outer radius of a vibrator using a photoelectric device. σ is the vibe center according to any definition. RO is the radius of a virtual perfect circle centered at 6 and located in the thick region. Points 1, 2, and 3 where the radiation beams B-1-2, B-2-3, and B-3-1 intersect in an equilateral triangle shape are on the virtual perfect circle, and these three
It is already clear from the above description that the diagonal wall thickness dimension along the beam direction can be determined by using each point as a wall thickness measurement point. The outer radius meter is composed of a light emitter and a light receiver. Floodlight 1-1 and photodiode array
The outer radius meter of the saw assembly is constructed by the photoreceiver FDA-3. Assuming that the point where the light beam F-1 projected from the light projector 1-1 and reaching the light receiver FDA-3 touches the outer wall of the vibrator is 1'', the measurement point 1 is on the line segment σ1''. The outer diameter of the vibrator is measured by moving the measurement system consisting of the emitter 1-1 and the light receiver FDA-3 to 9 relative to the vibrator and detecting the point where the beam F-1 touches the outer wall of the vibrator. Such outer radius meters that can respond at high speed are already commercially available. The same is true for each outer radius meter consisting of the light projector 1-2 and the light receiver 5FDA-1, and the light projector 1-3 and the light receiver FDA-2. In this way, according to the measurement system shown in FIG. 29, the diagonal wall thicknesses ξ1, ξ2, and ξ3 in the beam direction at measurement points 1, 2, and 37θ in the vibrator pressure area can be determined, and the true thickness at each measurement point can be determined. Outer radius RlPl (distance O''), R2F,l (distance σ2'')
, R3Pl (distance N3'') are found.

Three methods (1) to (Iiii) were previously explained as methods for converting the diagonal wall thickness ξ into the radial wall thickness X, but the accuracy of these methods was evaluated using the measurement results of the outer radius described above. can be increased. It is also useful for converting diagonal wall thickness to radial wall thickness for vibrators with poor roundness. Regarding the vibrator, the outer radius and inner radius (or radial wall thickness or diagonal wall thickness) at three points around it
If S is known, the shape of the vibrator at the peripheral position is almost known. The measurement system shown in FIG. 29 can be said to be a device for measuring the shape of a vibrator. It will be readily apparent that the three-point measurement can be expanded to five or more odd-numbered points. Further, in FIG. 29, when the vibrator is in a red-hot state and emits light by itself, a projector is not necessary. The invention has been described in terms of a number of embodiments.

As is clear from the above description, according to the present invention, even for a vibrator with relatively large local variations in the outer diameter and wall thickness, by appropriately selecting the measurement point, the wall thickness at the measurement point can be adjusted. It has the advantage that it is theoretically correct and can be measured accurately. This invention is not limited to steel pipes, and can be applied to vibrators made of other metals, plastics, glass, and other materials.
It can be carried out using rays, X-rays, β-rays, ultraviolet rays, visible light, infrared rays, etc.

In addition, when measuring wall thickness and outer radius at the same time, depending on the material of the vibrator to be measured, high-energy electromagnetic waves that pass through the material may be used for wall thickness measurement, or high-energy electromagnetic waves that pass through the material may be used for measuring outer radius. , a low-energy electromagnetic wave that does not pass through objects, or other sources, the present invention can be similarly applied. FIG. 30 is a conceptual diagram showing a modification of the invention.

In the same figure, beams B-1-3, B-2-3, B-3
Measurement according to this invention using -1! After determining the wall thickness dimensions of measurement points 1, 2, and 3 according to the method, the beam B-1
If the sum of the wall thickness X1 at measurement point 1 and the wall thickness X4 at point 4 is calculated using -4, since X1 is known, \ can be easily determined. If beam B-3-6 is used, the four wall thicknesses at point 6 can be found in the same way. This consists of 3 measurement points around the vibrator and 3 measurement points opposite each measurement point.
This is a method that allows you to know the wall thickness for a total of 6 points.
Even when the number of measurement points is an odd number of five or more, the wall thickness at the point opposite the measurement points can be easily determined in exactly the same way. FIG. 31 is a conceptual diagram showing yet another modification of the invention.

The device shown in the figure attempts to obtain the same results as measurements made by arranging multiple sets of measurement systems by rotating one set of measurement systems around the vibrator. . A radiation source container C containing a radiation source S and a radiation detector D are attached to the frame F1, which is supported so as to be able to rotate around the vibrator, as shown in the figure, and also measures the outer radius of the vibrator. The light emitter 1 and light receiver FDA may be attached as shown in the figure. By repeating measurements each time the measurement system is rotated at different angles around the center of the vibrator, the wall thickness and outer radius can be measured at five points around the vibrator, as shown in Figure 32. obtain. Since only one set of measurement systems is required, there is an advantage that the cost is low. Brief Description of the Drawings Fig. 1 is a conceptual diagram showing the principle of a method for measuring the wall thickness of a tubular material proposed by the present inventors and filed separately by the present applicant (Japanese Patent Application No. 1226/1982). , FIG. 1A is an explanatory diagram showing the dimensional relationship of the main parts in FIG. 1, FIG. 2 is a conceptual diagram showing the above measurement method when n (number of measurement points) = 9, and FIG. A conceptual diagram showing a modification example when n=9, FIG. 4 is a conceptual diagram showing yet another modification example when n=9, and FIG. 5 is a conceptual diagram showing an example when n=8. , FIG. 6 is a perspective view defining the cross section of the vibrator, FIG. 7 is a cross-sectional view of the vibrator for explaining roundness, and FIG. 8 is a cross section of the vibrator to which the measuring method according to the present invention is not applicable. The cross-sectional views shown in FIGS. 9 and 10 are cross-sectional views of a vibrator to which the measurement method according to the present invention can be applied, although they each have defects, and FIG. 11 is a cross-sectional view of a vibrator for defining the center. Figure 12 is a cross-sectional view of main parts of the vibrator wall thickness for defining the vibrator wall thickness, Figure 12A is an explanatory diagram showing a model of the dimensional relationship shown in Figure 12, and Figure 13 is a three-point measurement. FIG. 14 is an enlarged cross-sectional view of the main part of the vibrator's cross section, FIG. 15 is a cross-sectional view of the vibrator showing the measurement site in the case of three-point measurement, and FIG. 16 is a cross-sectional view of the vibrator modeled in the case of this invention. FIG. 17 is a conceptual diagram of the measurement system used when carrying out the measurement, and FIG. An enlarged explanatory diagram of the vicinity of the measurement point, FIG. 20 is an explanatory diagram corresponding to a superimposition of FIGS. 13 and 16,
Figures 21A and 21A and 21B are explanatory diagrams of the embodiment in the case of 5-point measurement according to the present invention, and Figure 22A, 2B and 2B are explanatory diagrams of the embodiment in the case of 7-point measurement according to the present invention, Figure 23 shows
Explanatory diagram of the embodiment when the measurement object is a triangular vibrator, 2nd
Figure 4 A is an explanatory diagram of an embodiment in which the mouth is a pentagonal vibrator, Figure 24 C is an explanatory diagram showing an example in a more general case of an odd-numbered vibrator, and Figure 25 is an explanatory diagram of an embodiment in which the mouth is a pentagonal vibrator. A conceptual diagram showing an embodiment of the present invention in the case of measurement using
Figures 26 and 27 are enlarged views of the vicinity of the measurement points in Figure 25, Figure 28 is a similar enlarged view showing the beam area passing through the wall thickness, and Figure 29 is an outer radius meter. FIG. 30 is a conceptual diagram showing the arrangement of the measurement system in the case of implementing this invention in combination with FIG.
FIG. 32 is a conceptual diagram showing yet another modification of the present invention.
The figure is a conceptual diagram showing an example of measurement results by the measurement system shown in FIG. 31.

Description of symbols 1... Radiation source, 2... Radiation source container, 3... Radiation beam, 4... Same detector, 5...・Measurement plane, 6... Cross section, 20... Tubular material, S... Radiation source, C.
...Radiation source container, D...Detector, ξ...
...Diagonal wall pressure, x... Radial wall thickness, R...
...Radius, Scl...Collimator, Dcl.
...Collimator, W...Resolution, d...
...beam width, 1... light emitter, FDA...
...Receiver, F1...Frame.

Claims (1)

[Scope of Claims] 1. Projecting the beams so that at least three radiation beams intersect with each other and form a regular-odd polygon with the intersection points as vertices, and all the vertices of the polygons are The tubular material is positioned so as to be included in the thick part of the tubular material, and the intensity of the radiation beam transmitted through the thick part of the tubular material is measured, and the measured values (d_1_2, d_2_3, d_3_
4,...d_n_1), the thickness dimension (x_1
, x_2, . . . x_n) is calculated as the pipe wall thickness. ξ_1=(1/2)(d_1_2-d_2_3+d_3
_4−...d_n_1)ξ_2=(1/2)(d_2_
3-d_3_4-d_4_5-...d_1_2)ξ_n
= (1/2) (d_n_1-d_1_2+d_2_3-
...d_n_-_1,_n)x_1=R_1-√R_1
^2-(A_1-ξ_1)ξ_1x_2=R_2-√R
_2^2-(A_2-ξ_2)ξ_2x_n=R_n-
√R_n^2-(A_n-ξ_n)ξ_nwhere A_n=
2√R_n^2-R_0sinθ)^2θ={(n-2
i)/2n}πn=(2m+1) m=1, 2, 3,... i=1, 2, 3,...m Note that the vertices of the polygon are given the signs 1, 2, 3...n in order. For example, the measured intensity of the radiation beam passing through apex 1 and 2 is expressed as d_1_2, that of the radiation beam passing through apex n and 1 is expressed as d_n_1, and the measured value of the radiation beam passing through apex n is expressed as d_n_1. The material thickness dimension is ξ
_n, the wall thickness of the tubular material at the apex n is expressed as x_n, the outer diameter dimension of the tubular material at the apex n is R_n, the apex 1,
Let R_0 be the radius of a virtual perfect circle that passes through all of 2,...n.