JPS6190005A - Measuring method of curvature of tubular body - Google Patents

Abstract

PURPOSE:To measure the curvature of a tube on on-line basis from the difference between the maximum and minimum value of the isolation distance between the outer peripheral surface of the tube and a reference position by detecting the isolation distance while rotating the tube in a circumferential direction. CONSTITUTION:The center of the pipe P between places where it is supported by supporting devices S is invariably on center lines of the devices, so when the pipe P which has curvature is rotated by rotating rolls R in a circumferential direction, the center of the pipe P runs on the axial line of a distance detector when the pipe P comes closest to and farthest from the distance detector D. Namely, the detector D is arranged right above the center point of the beam part of the pipe P or at >=2 optional positions in the lengthwise direction of the beam part to detect the distance to the upper end of the outer peripheral surface and obtain the maximum and minimum values, calculating the curvature of the pipe P. Thus, the curvature is measured on on-line basis in a manufacture line of a seam welded pipe, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The conventional method for measuring the bending of a baton-like object involves manually moving the object to be measured in the circumferential direction and placing it in a sheath-like device that supports both ends. Then, the amount of bending is determined by repeatedly measuring the displacement position of the central part in a stationary state (for example, the method of
4-146656) or a supporting device that has surfaces facing the vertical cross section at both ends of the object to be measured, sandwich and support the object in a fixed manner, and while rotating the object in the circumferential direction, A method of determining the amount of bending by measuring the amount of displacement has been proposed (for example, Japanese Patent Laid-Open No. 55-63709).

[Problem that the invention seeks to solve]

It is of course possible to measure bending using the measurement method described above, but in actual manufacturing processes, the product (object to be measured) is often a heavy object that is difficult to move manually, and even if it were possible to move it, However, when products are transferred at a high speed of once every 10 to 20 seconds, it is difficult to use a method of manually changing the circumferential position of the product as an online measurement method.

In addition, since the length of the product varies widely from several meters to several tens of meters, the manufacturing process is not flexible enough if the product is fixedly supported by a support device that has surfaces facing both end surfaces of the object to be measured. This poses a problem in that it significantly impairs high speed and is inefficient, making it difficult to put it to practical use as an online measurement method.

In view of these circumstances, the present invention provides a method for measuring the bending of a pipe online without interfering with manufacturing capacity, for example, in the pipe making process or finishing process of ERW welded pipe, or in a process close to this process, without interfering with manufacturing capacity. The purpose is to provide.

[Means for solving problems]

For this purpose, the method of the present invention supports the object to be measured in the state of a two-point support beam, sets a support device equipped with a rotation mechanism that rotates the object to be measured in the circumferential direction, and supports the object to be measured in the longitudinal direction of the beam. A distance detector is installed to detect the front corner distance between the outer peripheral surface of the object to be measured and a reference position at the center point or any two or more points, and the distance is detected while rotating the object to be measured. , a method for measuring the curvature of a baton-like object, characterized in that the amount of curvature of the object to be measured is calculated from the difference between the maximum value and the minimum value of the distance within one rotation of the object to be measured.

That is, in the manufacturing process of an ERW welded pipe, for example, the method of the present invention involves supporting the pipe in the form of a two-point support beam at an appropriate position within a cross-feeding table or on the exit side of the cross-feeding table; While rotating the tube in the circumferential direction using the rotation mechanism provided in the support device, the distance detector measures the relationship between the outer circumferential surface of the tube at the longitudinal center point of the beam section or any two or more points and the reference position. The front corner distance is detected and the amount of bending of the pipe is determined from the difference between its maximum and minimum values.

[Effect]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example in which the measuring method according to the present invention is applied to measuring the bending of a pipe will be explained based on the drawings.

FIG. 1a and FIG. 1b are a front view and a side view showing the support state of the object to be measured and the arrangement relationship of the distance detector in one embodiment of the present invention. In the figure, P is a pipe that is an object to be measured, and the pipe P is freely supported at two appropriate points in the longitudinal direction by a support device S, and is in the state of a two-point support beam.

The distance detectors are arranged at positions spaced apart from the reference plane of the support device S by a certain distance within a plane that includes the center line CL of the support devices S on both sides. As a distance m detector, for example,
Known detectors such as a length measuring needle using a laser or microwave, an eddy current displacement meter, a capacitance displacement meter, etc. can be used.

As shown in the figure, the center of the pipe P supported by the support device S is always on the center line CL of the support device S, so in the case of a curved pipe, when the pipe P is rotated, When P is closest to the distance detector and when it is farthest from it,
The center of the tube P passes on the axis of the distance detector. That is, the distance detector is placed directly above the center point of the beam section of the pipe P, or at any two points in the longitudinal direction of the beam section.
Distance ra to the upper end position of the outer circumferential surface of the pipe P
By detecting l and finding its maximum and minimum values,
The bend of the pipe P can be calculated.

FIGS. 2 and 3 are diagrams showing the arrangement of a distance detector in the case of using an imaging type distance detector that combines a light projector and a scanning photoelectric converter V as another embodiment, The vertical line passing through the center of the distance detector is perpendicular to the optical axis of the distance detector, and the distance between the tube P and the distance detector is such that even when the curved tube is rotated, the tube P exists at %i within the field of view of the distance detector. Once the detector is placed,
Since the distance from the reference position to the lower end position of the outer peripheral surface of the tube corresponds to the output of the bright part (or dark part) of the scanning photoelectric converter V, the difference between the maximum value and the minimum value of the output is calculated. The amount of bending of the pipe P can be calculated.

When measuring the bend of a pipe, if the bend itself is a simple arc as shown in Figure 4a, the measurement should be made at the center point in the longitudinal direction of the beam.
It is sufficient to perform the distance detection as described above, and the minimum value of the detected value Q min
The bending amount between the support points and the maximum value Qmax is determined by b = 1/2 (Qmax - Qmin). If the bend is a simple arc, the bend in the entire length of the pipe can be easily calculated from the above partial bend amount.

This calculation procedure is a simple geometric problem.

Explanation will be omitted. Note that the bending of actual products, especially the bending of heat-treated pipes, is not necessarily uniform in the longitudinal direction of the pipe, as shown in Figure 4b. or move the
By arranging multiple distance detectors and finding the difference between the maximum and minimum distances from the reference position for multiple points, it is possible to find the maximum amount of bending as well as the shape of the bend from a series of these differences. .

In addition, since the length of the product varies from several meters to several tens of meters, the tube support device should be movable in the longitudinal direction of the tube, or multiple units should be arranged in the longitudinal direction of the tube to support the tube as appropriate depending on the length of the product. It is preferable to allow selection.

In the embodiment, the distance detector is placed on a vertical line passing through the center of the pipe P on the vertical section of the pipe P, or the optical axis of the distance detector is placed so that the vertical line and the optical axis of the distance detector are perpendicular to each other. , we have explained an example of detecting the distance between the upper end position or lower end position of the pipe outer circumference and the reference position, but in principle, the position of the pipe outer circumferential surface to detect the distance from the reference position and the installation of a distance detector are explained. The position is not limited to the position in the embodiment, and the separation distance between an arbitrary angular position on the outer circumferential surface of the tube and the reference position can be detected by a distance detector provided at an appropriate position.

〔Effect of the invention〕

Since the method for measuring the bending of a tube/rod according to the present invention is as described above, it is possible to measure the bending on-line in the manufacturing line of tubes/rods, and it is also possible to measure the bending of the object to be measured. It is possible to perform accurate bending measurements by excluding the influence of deflection due to own weight, and the measurement results can be effectively fed back to operations, greatly contributing to improving product quality.

[Brief explanation of the drawing]

1a and 1b are diagrams showing the support state of the object to be measured and the arrangement relationship of the distance detector in one embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing the arrangement relationship of the distance detector in another embodiment of the present invention. Figures 4a and 4b showing the arrangement of the distance detectors are diagrams showing examples of the curved shape of the object to be measured. P: Pipe S: Support device R2 rotating roll D = Distance detector L: Floodlight
V: Photoelectric converter No. 4a■ No. 4b■ ￥r Special notification, 5 Procedural amendment (voluntary) July 25, 1985

Claims (1)

[Claims] A support device is provided that supports the object to be measured as a two-point support beam and also has a rotation mechanism that rotates the object in the circumferential direction.
A distance detector is set to detect the separation distance between the outer peripheral surface of the object to be measured and the reference position at more than one point, and the distance is detected while rotating the object to be measured, and the distance is detected within one rotation of the object to be measured. A method for measuring the curvature of a baton-like object, characterized in that the amount of curvature of the object to be measured is calculated from the difference between the maximum value and the minimum value of the distance.