JPH01320422A - Method and instrument for measuring pipe shape - Google Patents

Abstract

PURPOSE:To measure the shape of a pipe to be measured by utilizing ultrasonic waves transmitted from and received by three ultrasonic probes arranged around the pipe to be measured. CONSTITUTION:Three ultrasonic probes 28 are arranged so that they can encircle a pipe 10 to be measured through an ultrasonic medium. By transmitting and receiving 32 ultrasonic waves from and by the three probes 28 to and from the pipe 10, medium distances between the probes 10 and their corresponding outer peripheral surface of the pipe 10 are measured 35 and, simultaneously, the wall thicknesses of the pipe 10 at the points corresponding to the arranged positions of the probes 28 are measured 34. Then coordinates of the inner and outer peripheral surfaces at the three points are respectively calculated from the results obtained from the above-mentioned measurement and, from the coordinates, the center positions and diameters of the circumscribed circles of the triangles formed by connecting each three coordinates are respectively calculated. By respectively using the center positions and diameters of the circumscribed circles as the center positions and diameters of the inner and outer peripheral surfaces of the pipe 10, the shape of the pipe 10, such as the minimum and maximum wall thicknesses, average thickness, etc., can be calculated.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a pipe shape for measuring a predetermined pipe shape such as the maximum wall thickness, minimum wall thickness, or average wall thickness of pipe materials such as steel pipes and copper alloy pipes. The present invention relates to a measuring method and apparatus.

(Background technology) Measurement of the maximum wall thickness, minimum wall thickness, or average wall thickness of pipe materials such as steel pipes and copper alloy pipes is usually performed using a predetermined measurement method such as a micrometer at the pipe end. It is done manually using equipment.

However, with this method, not only is it inevitable for the inspector to make measurement errors, but the entire length of the pipe cannot be inspected.
In addition, the burden on inspectors is heavy, and there are also problems in that the shape of the tube cannot be measured on the tube material manufacturing line, so-called on-line measurement.

On the other hand, in recent years, methods using radiation and methods using ultrasonic waves have been proposed as methods for measuring tube shape without such problems.

However, the tube shape measurement method using radiation is
There are hygienic handling restrictions, and since it uses an absorption method, there is a long response time delay, making it not necessarily suitable for online measurement. Furthermore, the measurement method using such radiation has the disadvantage that, due to its measurement principle, it is not possible to measure the shape of a small diameter tube with an outer diameter of approximately 8 mm.

On the other hand, although the method of measuring tube shape using ultrasonic waves does not have the same problems as methods using radiation, it is conventionally difficult to measure the maximum and minimum wall thickness of the tube to be measured (tube material). Alternatively, in order to know the pipe shape such as the average wall thickness, it was necessary to rotate the pipe to be measured around the center line of its outer peripheral surface and measure the wall thickness of the pipe to be measured over its entire circumference.
The transport mechanism for the pipe under test must be provided with a function to rotate the pipe under test, which poses the problem of complicating the mechanism for transporting the pipe under test. In order to measure the tube shape sufficiently densely in the length direction, the feed rate of the tube to be measured must be kept low enough, so it is not necessarily suitable for production lines where the tube material is fed at a high rate. There is also the problem that it cannot be applied.

Ta. Furthermore, in conventional tube shape measurement methods using ultrasound, measurement errors become significantly large if the center position of the ultrasonic probe group and the center position of the outer circumferential surface of the tube to be measured do not exactly match. Therefore, a precise centripetal mechanism with high positioning accuracy is required to hold the tube to be measured so that the center position of the outer circumferential surface of the tube to be measured precisely matches the center position of the ultrasonic probe group. There was also the issue of doing so.

(Problem to be Solved) It is against this background that the present inventors have developed a method for producing raw steel pipes such as hot-rolled steel pipes and copper alloy pipes, which are the main targets of such measurement methods. The findings obtained from the analysis results of a large number of pipe shapes are as follows:
This was done based on the knowledge that although there are various forms of eccentricity and uneven thickness, the inner and outer peripheral surfaces can be considered to be fully circular within the allowable measurement error range, and this solution was developed. The problem to be solved is that there are no handling restrictions like methods using radiation, and the outer diameter is 8.
This method uses ultrasonic waves to measure the shape of pipes with a small diameter of about M.It is a pipe shape measurement method using ultrasonic waves that can measure the pipe shape of small diameter pipes of about M size. It is possible to measure a predetermined pipe shape such as wall thickness, minimum wall thickness, or average wall thickness sufficiently densely over the entire length of the pipe material, and without installing a precise centripetal mechanism with high positioning accuracy. It is an object of the present invention to provide a tube shape measuring method capable of measuring a predetermined tube shape of a tube with sufficiently high accuracy, and an apparatus for carrying out the measuring method.

(Solution Means) In order to solve this problem, in the present invention, three ultrasonic probes are arranged so as to surround the tube to be measured via an ultrasonic propagation medium, and the three ultrasonic probes are The three ultrasonic probes are positioned so that the ultrasonic waves transmitted from them toward the pipe to be measured intersect at one predetermined point, and the three ultrasonic probes are connected to the pipe to be measured. At the same time, the medium distance between each ultrasonic probe and the outer peripheral surface of the tube to be measured corresponding to the installation position of each ultrasonic probe is measured. The wall thickness of the part of the tube to be measured corresponding to the installation position of each ultrasonic probe is measured, and from the measurement results of the medium distance and the wall thickness of the tube to be measured, the thickness of the part of the tube corresponding to the installation position of each ultrasonic probe is measured. Calculate each of the three coordinates of the inner and outer circumferential surfaces of the measuring tube, and from the three coordinates of the inner and outer circumferential surfaces of the tube to be measured, calculate the center position of the circumcircle of the triangle whose vertices are the three coordinates. The center positions of the circumscribed circles of these triangles are set as the center positions of the inner and outer circumferential surfaces of the pipe to be measured, and the diameters of the circumscribed circles of these triangles are respectively calculated. Predetermined pipe shapes such as the minimum wall thickness, maximum wall thickness, and average wall thickness of the pipe to be measured are calculated as the diameters of the inner and outer circumferential surfaces.

The present invention also includes (A) a transport mechanism that moves the tube to be measured in the direction of its center line; Three ultrasonic probes that transmit and receive ultrasonic waves towards the pipe to be measured; (D) wall thickness measuring means for measuring the wall thickness of the portions of the tube to be measured corresponding to the placement positions of the ultrasonic probes; Based on the transmission and reception of ultrasonic waves by these ultrasonic probes, the wall thickness is measured by each corresponding wall thickness measuring means, and at the same time, the corresponding ultrasonic probe and the placement position of the ultrasonic probe are measured. (E) an ultrasonic medium distance measured by the medium distance measuring means and a medium distance measured by the wall thickness measuring means; (F) coordinate calculation means for calculating the coordinates of the inner and outer circumferential surface parts of the tube to be measured corresponding to the placement positions of the respective ultrasonic probes, based on the wall thicknesses calculated by the coordinate calculation means; Based on the three coordinates of the inner and outer circumferential surfaces of the branch measuring tube, calculate the center position and diameter of the circumscribed circle of the triangle whose vertices are each of these three coordinates, and calculate the center position and diameter of the circumscribed circle of each triangle. The pipe shape measuring device is configured to include inner and outer circumferential surface center position/diameter calculation means for determining the position and diameter as the center position and diameter of the inner and outer circumferential surfaces of the pipe to be measured, respectively.

Furthermore, in the present invention, (a) a medium container containing an ultrasonic propagation medium; and (b) a tube to be measured is inserted into the medium container, and a part of the tube to be measured is inserted into the container. a conveyance mechanism for moving the ultrasonic propagation medium in the direction of its center line while being immersed in the ultrasonic propagation medium in the medium storage container; (d) three ultrasonic waves disposed surrounding the tube to be measured in the ultrasonic propagation medium in the medium storage container and transmitting and receiving ultrasonic waves toward the tube to be measured; (e) a sonic probe, which is connected to the three ultrasonic probes and corresponds to the placement position of the ultrasonic probes based on the transmission and reception of ultrasonic waves by the ultrasonic probes; (f) a wall thickness measuring means for measuring the wall thickness of each portion of the tube to be measured; , At the same time as the wall thickness is measured by each corresponding wall thickness measuring means, the medium between the corresponding ultrasonic probe and the outer/circumferential surface of the tube to be measured corresponding to the placement position of the ultrasonic probe is measured. a medium distance measuring means for measuring a distance; and (8) a temperature compensating means for measuring the temperature of the ultrasonic propagation medium and correcting measurement errors in the medium distance and the wall thickness due to temperature changes in the ultrasonic propagation medium. and (h) determining the arrangement of the three ultrasonic probes based on the medium distance and wall thickness measured by the ultrasonic medium distance measuring means and the wall thickness measuring means and temperature-corrected by the temperature compensating means. Coordinate calculation means for calculating the coordinates of the inner and outer peripheral surface parts of the pipe to be measured corresponding to the installation position;
i) Based on each of the three coordinates of the inner and outer circumferential surface parts of the pipe to be measured calculated by the coordinate calculation means, calculate the center position and diameter of a circumscribed circle of a triangle with each of these three coordinates as the apex. , a pipe shape measuring device is configured to include inner and outer circumferential surface center position/diameter calculation means for calculating the center position and diameter of the circumscribed circle of each triangle as the center position and diameter of the inner and outer circumferential surfaces of the pipe to be measured. I decided to do so.

(Function) As mentioned above, according to the research conducted by the present inventors, both the inner and outer circumferential surfaces of raw steel pipes such as steel pipes and copper alloy pipes, whose shape is mainly measured, are It can be considered a perfect circle. Therefore, when using these steel pipes as pipes to be measured,
If the diameters of the inner and outer peripheral surfaces and their eccentricity are known, the maximum wall thickness, minimum wall thickness, average wall thickness, etc. can be determined from the diameters of the inner and outer peripheral surfaces and their eccentricity. You can know the shape of the tube.

Here, in order to find the amount of eccentricity between the inner circumferential surface and the outer circumferential surface of the pipe to be measured, it is sufficient to know the center position of the inner circumferential surface and the center position of the outer circumferential surface. In order to know the center position of the surface, it is sufficient to know the positions of three points spaced apart in the circumferential direction on the inner circumferential surface and the outer circumferential surface, respectively.

If we know the positions of three points separated in the circumferential direction on the inner circumferential surface, we can find the center position of the inner circumferential surface by finding the center position of the circumcircle of the triangle whose vertices are the positions of those three points. In addition, if we know the positions of three points spaced apart in the circumferential direction on the outer circumferential surface, we can find the center position of the outer circumferential surface by finding the center position of the circumcircle of the triangle whose vertices are the positions of those three points. can be found. In this way, if the center positions of the inner circumferential surface and the outer circumferential surface are known, the amount of eccentricity between the inner circumferential surface and the outer circumferential surface can be known as the amount of deviation between these center positions, and the amount of eccentricity between the inner circumferential surface and the outer circumferential surface If the center positions of the inner and outer circumferential surfaces are known, the inner and outer circumferential surfaces can be Based on the diameters of the inner and outer circumferential surfaces and the amount of eccentricity, the maximum wall thickness, minimum wall thickness, and
It is possible to know the predetermined shape of the tube, such as the average wall thickness.

By the way, in the method of the present invention, three ultrasonic probes are arranged so as to surround the tube to be measured, and based on the transmission and reception of ultrasonic waves from these three ultrasonic probes, the three ultrasonic probes are
The medium distance between two ultrasonic probes and the outer peripheral surface of the tube to be measured corresponding to the placement position of the ultrasonic probes, and the tube to be measured corresponding to the placement position of each ultrasonic probe. Since the wall thickness of each part is measured, based on the measurement results and the placement position of each ultrasonic probe, each part on the inner and outer circumferential surfaces of the pipe to be measured is The position coordinates of the three parts can be determined.

Therefore, if the center position of the circumscribed circle of a triangle whose vertices are the coordinate positions of each of the three parts on the inner and outer circumferential surfaces of the pipe to be measured determined in this way is calculated, the result of these calculations will be The center positions of the inner circumferential surface and outer circumferential surface of the tube can be determined, and the amount of eccentricity, which is the amount of deviation of these center positions, can be determined. Furthermore, if the center positions of the inner and outer circumferential surfaces are known, the diameters of the inner and outer circumferential surfaces of the pipe to be measured can be determined as the diameters of the circumscribed circles of each of the triangles, as described above. Based on these diameters and the above-mentioned eccentricity, it is possible to calculate and obtain a predetermined pipe shape such as the maximum wall thickness, minimum wall thickness, or average wall thickness of the pipe to be measured.

In the method of the present invention, the coordinates of each of the three parts on the inner and outer circumferential surfaces of the tube to be measured are determined based on the transmission and reception of the three ultrasonic probes arranged around the tube to be measured. By determining the maximum wall thickness, minimum wall thickness, or average wall thickness of the pipe under test, it is possible to calculate the specified pipe shape, such as the maximum wall thickness, minimum wall thickness, or average wall thickness. There is no need to rotate the tube around the center line of the surface, so the mechanism for transporting the tube to be measured can be made simpler than before, and the feeding speed of the tube to be measured can be made sufficiently high. This makes it possible to measure the shape of the tube to be measured with sufficient precision in its length direction while maintaining the shape of the tube.

Furthermore, according to the method of the present invention, even if the center position of the ultrasonic probe group and the center position of the outer peripheral surface of the tube to be measured are slightly deviated,
In other words, the predetermined shape of the pipe to be measured, such as maximum wall thickness, minimum wall thickness, and average wall thickness, can be measured with sufficiently high accuracy without using a precise centripetal mechanism with high positioning accuracy as in conventional methods. This is possible.

According to the device of the present invention, the technique of the present invention can be advantageously implemented.

As is clear from the above description, in the method and apparatus of the present invention, only raw steel pipes such as steel pipes and copper alloy pipes are to be measured; Pipe materials other than steel pipes can be measured as long as both the inner and outer circumferential surfaces are perfectly circular within the measurement error range.

(Example) Hereinafter, in order to clarify the present invention more specifically,
One embodiment thereof will be described in detail based on the drawings. In addition,
The pipe material to be measured here is raw steel pipes such as steel pipes and copper alloy pipes, but if the inner and outer peripheral surfaces are sufficiently round within the allowable measurement error range, pipes other than raw steel pipes can be used. Materials can also be measured.

First, FIG. 1 schematically shows an example of a tube shape measuring device according to the present invention. There, 10 is a pipe to be measured (pipe material) as a pipe to be measured, and a water tank 12
Pinch rollers 14 as a conveyance mechanism arranged before and after the
, 14, so as to be able to pass through the water tank 12 and move in the axial direction. This water layer 12 contains water as an ultrasonic propagation medium so as to surround the pipe 10 to be measured. 18.

Note that the tube to be measured 10 and the sealing member 2 are placed on both sides of the water tank 12.
It is also possible to provide an auxiliary water tank for accommodating the water flowing out from between 0.20 and 20, and configure the water circulation path including the auxiliary water tank.

Here, three ultrasonic probes 28 are disposed within the water tank 12 and are held by a predetermined holding device 24 . As shown in FIG. 3, these three ultrasonic probes 28 are arranged so that ultrasonic waves propagate on the same circumference=P with a radius L centered at the intersection point Po where each ultrasonic wave intersects. Through water as a medium, the pipes 10 to be measured are separated by 120° from each other in the circumferential direction.
They are arranged so as to surround each other with a phase difference of . As shown in FIG. 2, three ultrasonic transmitting/receiving circuits 32 of the ultrasonic processing device 30 are connected to these three ultrasonic probes 28, respectively. Accordingly, ultrasonic waves are transmitted and received from each ultrasonic probe 2nd toward the intersection point Po where the ultrasonic waves intersect.

Note that the tube to be measured 10 has a center position of its outer peripheral surface 26: 0
It is held by a predetermined centripetal mechanism (not shown) so that ゜ coincides with the intersection point Po where the three ultrasonic probes 28 intersect, but this centripetal mechanism is highly accurate. It is not necessary to connect the tube 10 to be measured with three ultrasonic probes 2.
Any device having the function of holding it approximately in the middle position of 8 may be used.

Three wall thickness measuring devices 34 as wall thickness measuring means and three medium distance measuring devices 35 as medium distance measuring means are connected to each ultrasonic transmitting/receiving circuit 32. Corresponding wall thickness measuring device 3
4 and the medium distance measuring device 35 are supplied with ultrasonic transmission/reception signals. Then, in each wall thickness measuring device 34, the placement position of each corresponding ultrasound probe 28 is determined based on the transmission/reception signal from the ultrasound transmission/reception circuit 32:
The wall thickness of the 1° portion of the tube to be measured corresponding to Pl, Pz, P- is measured: L1 + tz + t3, and at the same time, each medium distance measuring device 3
5, a portion of the outer circumferential surface 26 of the tube to be measured 1o corresponding to each corresponding ultrasonic probe 28 and its installation position: ol,
o□, 0. Medium distance between: p,,i! z, 13 is now measured (see Figure 3). Then, from the ultrasonic processing device 30 to the computer 36, the wall thicknesses: t+, z, tz and the medium distance measured by the wall thickness measuring device 34 and the medium distance measuring device 35 are also sent: i! ,, ,lx,I! , :r are supplied. In FIG. 2, 3 is a waveform monitor device, and 40 is an interface circuit.

By the way, a temperature sensor 41 is immersed in the water in the storage tank 16, and a temperature measuring device 42 is connected to this temperature sensor 41.

Then, from this temperature measuring device 42, the computer 36
, water temperature data representing the water temperature in the storage tank 16 and, by extension, the water temperature in the water tank 12 is supplied. Further, a setting device 44 is connected to the computer 36, and the setting device 44 inputs coordinate data representing the placement position of the ultrasound probe 28: pl, pz, pt. It has become.

Then, the computer 36 processes the wall thickness data, medium distance data, water temperature data, position coordinate data of the ultrasonic probe 28, etc. according to a predetermined program.
Diameter of inner peripheral surface 6° of tube to be measured 1O: D, diameter of outer peripheral surface 26: Do, maximum wall thickness) 'r'+amx l Minimum wall thickness: T, Il, average wall thickness: 〒.

A predetermined pipe shape such as thickness unevenness rate ΔT is calculated, and the calculated pipe shape of the tube 10 to be measured is displayed on the CRT4.
6 and printed out using a printer 48. Further, as will be described later, if the value of the thickness unevenness ratio ΔT obtained as a result of the calculation is an abnormal value larger than a preset tolerance value ΔT0, the computer 36 issues an alarm to the control unit 50. A signal is outputted to generate an alarm using an alarm device (not shown), and an abnormality mark is attached to the tube 10 to be measured using the marker 52.

Here, a tube end sensor 54 such as a photoelectric tube is disposed in front of the water tank 12, and when the tip of the tube 10 to be measured is detected by the tube end sensor 54, the control unit 50 sends a combiator. Measurement start signal at 36: SS
is now entered. On the other hand, a tube end sensor 56 is disposed at the back of the water tank 12, and when the tube end sensor 56 detects the rear end of the tube 10 to be measured, the control unit 50 sends a message to the computer 36 to end the measurement. Signal: SE is input. and,
Here, when a measurement start signal: SS is input from the control unit 50 to the computer 36, a measurement operation based on transmission and reception of ultrasonic waves from the ultrasound probe 28 is started, and a measurement end signal: SE is input. When the measurement operation is completed, the measurement operation is terminated.

In FIG. 1, reference numeral 58 is an air blowing nozzle for blowing compressed air onto the outer circumferential surface of the tube to be measured 10 to remove moisture adhering to the outer circumferential surface of the tube to be measured 10. be.

Next, based on the flowchart of FIG. 4 showing the program of the computer 36, the method of this embodiment will be explained while explaining the operation of the apparatus of this embodiment.

When the program starts, first, step S1 is executed, and it is determined whether or not a measurement start signal SS is input from the control unit 5o.

When it is confirmed that the measurement start signal: SS has been input, step S2 is subsequently executed, and the ultrasonic wave transmission command signal: ST is simultaneously sent to each ultrasonic transmitting/receiving circuit 32 of the ultrasonic processing device 30. Output. As a result, the intersection point where each ultrasonic wave intersects: Po, that is, the pipe to be measured 1
The center of the outer circumferential surface 26 of the tube 10 to be measured 10: Ultrasonic waves are simultaneously transmitted toward the center of the outer circumferential surface 26 of the tube 10 to be measured from 0 degrees to its vicinity.
The reflected waves of the ultrasonic waves reflected at the inner circumferential surface 60 are received by the ultrasonic probes 28, and the corresponding thickness measurement device 34 and medium distance measurement device 35 calculate the thickness 'Ll+t2. ．． t3 and medium distance: p-,,i□
,! , is measured.

By executing step S2, the wall thickness: Ll.

M2. and medium distance: lr, l□, 2. When is measured, in the following step S3, the wall thickness: t, t-
Measurement data of t, tx and medium distance: 11, 12°j2 are read, and the temperature of water as an ultrasonic propagation medium: θ is read from the temperature measuring device 42. Then, in step S4, which is subsequently executed, the thickness: tlttz+L, the medium distance: ll,
12. is is corrected by the water temperature: θ, and further, in the subsequent step S5, the wall thickness corrected by the water temperature: θ:
1. ．． 1. .

t, and medium distance: ll, 42z, !
3 and the preset placement positions of each ultrasound probe 28:
Pl.

Based on the position coordinates of Pz and Ps, the respective installation positions of the ultrasound probes 28: P1. Positions of three points on the inner peripheral surface 6o of the portion of the tube to be measured 10 corresponding to Pg and P2: Il+
Each coordinate of L, Is (Xil, Yi,).

(X, □, Yl!), (Yi3.Y, , ), and the positions of three points on the outer peripheral surface 26: O,, O□, 0. Each coordinate (X
o+, You), (Xoz, Yot), (
XO3, Yot) is calculated.

In addition, here, each ultrasound probe 2 days is 120 times each other.
For example, because they are arranged with a phase difference of °,
Considering the orthogonal coordinates with Pl as the origin (0, O) as shown in FIG. 3, the positions of three points on the inner circumferential surface 60 of the tube to be measured 10 are: 1. ．． 1. .

■Each of the coordinates of 3 can be calculated as - You can ask like this.

Furthermore, as is clear from the above description, here step S4. Temperature sensor 41. The temperature measuring device 42 and the like constitute a temperature compensating means, and the step S5 constitutes a coordinate calculating means.

3 on the inner circumferential surface 60 of the tube to be measured 10 in step S5.
When the coordinates of the point positions: l, , L, r3 and the coordinates of the three points on the outer peripheral surface 26: O,, O□, 03 are determined,
In the following step S6, the positions of these three points: l, , L, 1 . and O7,0
□, the circumscribed circle of each triangle with 03 as its apex, that is, the center position of the inner circumferential surface 60 and outer circumferential surface 26 of the tube to be measured 10:
1. ．． The coordinates of O, (XIO, Yi.), (Xo,
.

Yo. ) is calculated. Then, in step S7 that is executed subsequent to step S6, the coordinates (X, ., Y, .) of the center position of the inner peripheral surface 60 of the tube to be measured 10 obtained in step S6 (X, ., Y, .) and the outer peripheral surface 26 Center position: 0° coordinates (based on Xoo, Yool,
The amount of eccentricity: e between the inner circumferential surface 60 and the outer circumferential surface 26 is calculated.

Note that the coordinates (Xi., Y!.) of the center position of the inner circumferential surface 60 of the tube to be measured 10: Io and the center position of the outer circumferential surface 26: 0
The coordinates of ° (Xoo, Yoo) and the eccentricity between the inner circumferential surface 60 and outer circumferential surface 26 of the tube 10 to be measured: e are:
Specifically, it is determined as follows.

That is, 11. The center position: 10 of the circumcircle of the triangle whose vertices are L and lx can be found as the intersection of the perpendicular bisectors, as shown in FIG.

Here, the linear equation of line segment: II I2 is Y r l”
From aXi1+bYiz=aX12+b, Y, 2-Y,.

xtz X, 1l Xi! -Xil Because it is required, becomes.

Similarly, the linear equation of the line segment 13 I becomes as follows.

On the other hand, line segment: I, 1. The linear equation of the perpendicular bisector of is that the perpendicular bisector passes through the coordinate position of , and its slope: a is Y = z - Y
Since it is expressed as ++, it becomes...(3).

Similarly, line segment: 1. The linear equation of the perpendicular bisector of I is: Ylow Yi+ 2 2(Y+3 Yt+)
・ ・ ・(4)

Therefore, the coordinates (Xi., YiO) of the center position: Io of the inner circumferential surface 60 of the tube to be measured 10 are determined by the above (3) and (4).
) can be obtained as the solution (x, y) of the simultaneous equations. In other words, here, the solution of such simultaneous equations (where x, yl is the center position of the inner circumferential surface 60 of the tube to be measured 10. The coordinates (Xi., Y4°) are found, and Similarly, the coordinates (Xoo, Y, . . . ) of the center position of the outer circumferential surface 26 of the tube to be measured 60 at 0° are determined.

Furthermore, the eccentricity e between the inner circumferential surface 60 and the outer circumferential surface 26 of the tube to be measured IO is the center position of the inner circumferential surface 60 determined in this way; ■. Coordinates (x, 0. Y=o) Center position of O and outer circumferential surface 26: Coordinates of 0° (Xo.

Yo. ), it is determined according to the following equation (5).

When step S7 is completed, continue with Ste knob S8.
is executed, and the following (
6) According to the formula, the diameter of the inner circumferential surface 60: DL (radius:
rt ) is calculated, and also based on the coordinates of the center position: Oo of the outer peripheral surface 26 of the tube to be measured 10, the following (7) is calculated.
According to the formula, the diameter of the outer peripheral surface 26: Do (radius: ro
) is calculated.

Then, in step S9, from the radius of the inner circumferential surface 60 of the tube to be measured 1O: ri, the radius of the outer circumferential surface 26: ra, and the eccentricity: e, according to the following equations (8) to 01,
Average wall thickness: 〒、Maximum wall thickness: Ta5x + Minimum wall thickness'
Tl1lli11+thickness unevenness rate: ΔT is calculated. Then, in the subsequent step knob S10, those calculation results are calculated as follows: diameter of the outer circumferential surface 26 of the tube to be measured 10: Do, inner circumferential surface 60.
Diameter = D! It is also displayed on the CRT 46 and printed out on the printer 48.

...(7) T=ro ri H+ ・
(8) Tamx=ro-ri+e −
−・(9) Tmin=rort e
(IQ) As is clear from the above description, steps S6 and S8 constitute the inner and outer peripheral surface center position/diameter calculation means.

Ste-knob SL executed following step S10
In l, it is determined whether the thickness unevenness rate: 8T obtained in step S9 is larger than a preset tolerance value: ΔT0, and the thickness unevenness rate: ΔT is the tolerance 1i! : If it is within 610, step S12 is executed immediately, but if not, step S1 is executed before executing step S12.
3 is executed and an alarm signal S is sent to the control unit 50.
A is output. Then, when the alarm signal SA is output to the control unit 50 by executing step S13, an alarm is generated by the alarm device (not shown) and an abnormality mark is marked on the tube to be measured 10 by the marker 52, as described above. Granted.

On the other hand, in step S12 executed after the end of step Sll or S13, it is determined whether the measurement end signal SE has been manually input from the control unit 50, and if the measurement end signal SE has not been input yet, step S2 is executed, and the operation of measuring the pipe shape by transmitting and receiving ultrasonic waves is repeated. However, when it is confirmed that the measurement end signal SE has been input, the program ends and the pipe shape measurement operation for one pipework O to be measured is repeated. The shape measurement operation is completed.

As is clear from the above description, according to this embodiment, the tube to be measured 10 is detected based on the transmission and reception of ultrasonic waves by the three ultrasonic probes 28 disposed around the tube to be measured 10. Maximum wall thickness without rotating around center line
aX-, minimum wall thickness 2T10, average wall thickness: 〒, thickness unevenness rate: Δ
It is possible to measure tube shapes such as T, and the transport mechanism for transporting the tube 10 to be measured can be simpler than in the past.

Furthermore, since the tube shape can be measured without rotating the tube to be measured 10, even when measuring the tube shape sufficiently densely in the length direction of the tube to be measured 10, the tube to be measured 10 cannot be fed at a sufficiently high speed. Therefore, it can be suitably applied to pipe manufacturing lines with high line speeds.

Furthermore, even if the center of the outer circumferential surface 26 of the tube to be measured 10 and the intersection of the three ultrasonic waves do not exactly match, the maximum wall thickness: T lj m X, the minimum wall thickness: T m r
It is possible to measure pipe shapes such as n, average wall thickness: T, wall thickness deviation rate: ΔT, etc. with sufficient accuracy, and therefore it is easier and cheaper than conventional methods to perform maintenance and adjustment. A core mechanism can be adopted.

Although one embodiment of the present invention has been described in detail above, this is a literal illustration, and the present invention is not limited to such specific example (within the scope of the spirit thereof).
It goes without saying that the present invention can be implemented with various changes, modifications, improvements, etc.

For example, in the embodiment described above, the three ultrasound probes 28 were arranged with a phase difference of 120 degrees, but the arrangement positions of the ultrasound probes 28 do not necessarily have such a phase relationship. It is not limited.

Further, in the above embodiment, a separate wall thickness measuring device 34 and a medium distance measuring device 35 are connected to each of the three ultrasonic probes 28, and the placement positions of each ultrasonic probe 28 are as follows:
The wall thickness of the portion of the tube to be measured 10 corresponding to P, , P, , P3: t, tz, t3 and the medium distance between the ultrasonic probe 28 and the outer peripheral surface 26 of the tube to be measured IO: I ! ,, ,
j2. , f, were measured by the wall thickness measuring device 34 and the medium distance measuring device 35 corresponding to each ultrasonic probe 28, respectively, but as shown in FIG.
Each of the three ultrasonic probes 28 is connected to a wall thickness measuring device 34 and a medium distance measuring device 35 each having a built-in multiplexer. Thickness: Ll by thickness measuring device 34 and medium distance measuring device 35.

tz, t:+ and medium distance: ffi,, f,, ff1
It is also possible to measure 3.

Furthermore, in the embodiment described above, the temperature of the water as the ultrasonic propagation medium: θ was measured in the storage tank 16, but the temperature of the water: θ was measured directly in the water tank 12. It is also possible to use oil or fat as the ultrasonic propagation medium.

(Effect of the invention) As is clear from the above explanation, according to the method of the present invention,
Based on the transmission and reception of ultrasonic waves from three ultrasonic probes fixedly arranged around the tube to be measured, the maximum wall thickness can be determined without rotating the tube to be measured around the center line of its outer circumferential surface. Since it is possible to measure the tube shape such as minimum wall thickness and average wall thickness, it is possible to simplify the transport mechanism for sending the tube to be measured IO than before, and to maintain the feeding speed of the tube to be measured at a sufficiently high speed. At the same time, it is possible to measure the shape of the pipe to be measured sufficiently densely over its entire length, and since a precise centripetal mechanism is not required, maintenance and management are easy, and the device can be simplified. It is possible to achieve this goal. According to the apparatus of the present invention, the method of the present invention can be suitably implemented.

[Brief explanation of the drawing]

FIG. 1 is a system diagram schematically showing an example of a tube shape measuring device according to the present invention, and FIG. 2 is a block diagram showing the ultrasonic processing device in FIG. 1. FIG. 3 is an explanatory diagram for explaining the arrangement state of the ultrasonic probe in the measuring device of FIG. 1, and FIG.
5 is a flowchart for explaining the operation of the measuring device shown in FIG. 1, and FIG. 5 is an explanatory diagram for explaining a method for calculating the center position of the inner circumferential surface of the tube to be measured in the measuring device shown in FIG. FIG. 6 is a diagram corresponding to FIG. 2 showing another example of the tube shape measuring device according to the present invention. 10: Pipe to be measured 12: Water tank 14: Pinch roller 26: Outer circumferential surface 28: Ultrasonic probe 34: Thickness measuring device 35: Medium distance measuring device 36: Computer 44: Setting device 50: Control unit 60: Inner circumference Applicant: Sumitomo Light Metal Industries, Ltd. Figure 3 Figure 5 I3 (Xig, Yi31)

Claims (3)

[Claims] (1) Three ultrasonic probes are arranged to surround the tube to be measured via an ultrasonic propagation medium, and each of the three ultrasonic probes is transmitted toward the tube to be measured. The three ultrasonic probes are positioned so that the generated ultrasonic waves intersect at one predetermined point, and the three ultrasonic probes transmit and receive ultrasonic waves toward the tube to be measured. At the same time, measure the medium distance between the outer peripheral surface of the tube to be measured corresponding to the placement position of each ultrasonic probe, and at the same time measure the wall thickness of the portion of the tube to be measured corresponding to the placement position of each of the ultrasonic probes. Then, from the measurement results of the medium distance and the wall thickness of the tube to be measured, calculate the three coordinates of the inner and outer circumferential surface parts of the tube to be measured corresponding to the placement positions of each ultrasonic probe, and From each of the three coordinates of the inner and outer circumferential surface parts of the pipe to be measured, calculate the center position and diameter of the circumscribed circle of a triangle whose vertices are each of these three coordinates, and calculate the center position of the circumscribed circle of each triangle. The minimum wall thickness, maximum wall thickness, and average wall thickness of the pipe to be measured are set as the center position of the inner and outer circumferential surfaces of the pipe to be measured, and the diameters of the circumscribed circles of these triangles are respectively the diameters of the inner and outer circumferential surfaces of the pipe to be measured. A pipe shape measuring method characterized by calculating a predetermined pipe shape such as wall thickness. (2) A transport mechanism that moves the tube to be measured in the direction of its center line, and is arranged to surround the tube to be measured via an ultrasonic propagation medium, and transmits and receives ultrasonic waves toward the tube to be measured. Three ultrasonic probes, connected to the three ultrasonic probes, and corresponds to the placement position of the ultrasonic probes based on the transmission and reception of ultrasonic waves by the ultrasonic probes. a wall thickness measuring means for measuring the wall thickness of each portion of the pipe to be measured; At the same time as measuring the wall thickness by the corresponding wall thickness measuring means, measure the medium distance between the corresponding ultrasonic probe and the outer peripheral surface of the tube to be measured corresponding to the placement position of the ultrasonic probe. a medium distance measuring means for measuring the medium distance, and a medium distance measuring means for measuring the measured object corresponding to the arrangement position of each ultrasonic probe based on the medium distance measured by the medium distance measuring means and the wall thickness measured by the wall thickness measuring means. a coordinate calculating means for calculating the coordinates of the inner and outer circumferential surface parts of the pipe; and based on each of the three coordinates of the inner and outer circumferential surface parts of the pipe to be measured calculated by the coordinate calculating means, each of the three coordinates is determined as a vertex. Calculate the center position and diameter of the circumscribed circle of each triangle, and calculate the center position and diameter of the circumscribed circle of each triangle as the center position and diameter of the inner and outer circumferential surfaces of the pipe to be measured. A pipe shape measuring device comprising: diameter calculating means. (3) A medium container containing an ultrasonic propagation medium, and a tube to be measured inserted through the medium container, and a part of the tube to be measured is immersed in the ultrasonic propagation medium in the medium container. a conveying mechanism for moving the ultrasonic propagation medium in the direction of its center line while causing the ultrasonic propagation medium to flow out of the medium storage container; circulation pump means for circulating the ultrasonic propagation medium flowing out from the medium storage container into the medium storage container; Therein, three ultrasonic probes are arranged to surround the tube to be measured and transmit and receive ultrasonic waves toward the tube to be measured, and are connected to the three ultrasonic probes, 3. Wall thickness measuring means for measuring the wall thickness of the portion of the tube to be measured corresponding to the placement position of the ultrasonic probes based on the transmission and reception of ultrasonic waves by the ultrasonic probes; Based on the transmission and reception of ultrasonic waves by the ultrasonic probes, the wall thickness is measured by each corresponding wall thickness measuring means, and simultaneously the corresponding ultrasonic probe a medium distance measuring means for measuring a medium distance between the ultrasonic probe and the outer circumferential surface of the tube to be measured, which corresponds to the placement position of the ultrasonic probe; Temperature compensating means for correcting measurement errors in the medium distance and the wall thickness due to temperature changes in the propagation medium; and a medium distance measured by the medium distance measuring means and the wall thickness measuring means and temperature-corrected by the temperature compensating means. and a coordinate calculation means for calculating the coordinates of the inner and outer circumferential surface parts of the tube to be measured corresponding to the installation positions of the three ultrasonic probes, respectively, based on the position of the three ultrasonic probes; Based on each of the three coordinates of the inner and outer circumferential surface parts of the pipe to be measured, calculate the center position and diameter of the circumscribed circle of a triangle whose vertices are each of these three coordinates, and calculate the center position of the circumscribed circle of each triangle. and inner and outer circumferential surface center position/diameter calculating means for calculating the diameter as the center position and diameter of the inner and outer circumferential surfaces of the pipe to be measured, respectively.