JPH11194103A - Detecting method for foreign body at inside of electric resistance welded pipe, display device for foreign body and electric resistance welded pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus, for the display of a foreign body, in which the detection of the foreign body existing at the inside of an electric resistance welded pipe flowing into one after another and the existence of the foreign body can be marked automatically and surely without a need of labor. SOLUTION: A method and an apparatus are constituted in such a way that an X-ray detection output screen which is obtained at a time when X-rays are transmitted through an electric resistance welded pipe 15 is photographed, that the existence of a foreign body is detected on the basis of an image signal obtained by photographing the screen, that the existence of the foreign body is stored, that the relationship between the arrival of the foreign body at the position of a device 25 used to perform a laser marking operation to the outer face of the electric resistance welded pipe 15 and the time is found and that the marking operation is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for displaying foreign matter in an ERW pipe.

[0002]

2. Description of the Related Art It is well known to manufacture an electric resistance welded tube in which a thin plate coil is formed into a tube by a roll and the tube is completed by welding. The electric resistance welded tube formed in this manner is cut off by running according to a standard or a user's request to have an appropriate length.

Conventionally, the presence or absence of foreign matter such as burrs generated on the inner surface of a pipe during welding or cutting or residue left inside the pipe and its position have been detected visually.

As an example of an X-ray apparatus capable of capturing an X-ray fluoroscopic image, there is JP-A-9-33450 or JP-A-6-265486.

[0005]

In such an electric resistance welded pipe manufacturing line, the bead along the weld line on the outer surface of the pipe can be easily removed. The detection of the position requires a great deal of labor, and the location setting / marking as a guide for removal also requires a great deal of labor, so that the inspection has to be automated. In particular, a technique different from the processing of the outer surface image has been required for detecting foreign matter inside the electric resistance welded tube which is a long tube, which flows at a high speed such as 2 m / sec.

An object of the present invention is to provide a method and an apparatus for displaying a foreign object in an electric resistance welded tube, which solve such problems.

[0007]

According to the present invention, an image in an electric resistance welded tube is formed by using an X-ray apparatus, and the presence or absence of a foreign substance, the presence or absence of a foreign substance, and the position of a foreign substance are calculated by image processing.
And / or to provide an ERW pipe in which an outer surface position corresponding to a position of a foreign substance existing inside the ERW pipe that continues to flow is appropriately marked.

Specifically, the present invention proposes the following means.

The present invention relates to a method for detecting foreign matter in an electric resistance welded pipe, which detects foreign matter such as burrs existing inside an electric resistance welded pipe manufactured by a pipe machining and welding process by flowing through an electric resistance welded pipe production line. An X-ray detection output image obtained by transmitting X-rays through an ERW tube is captured, and the presence of a foreign substance and the position of the presence in the ERW tube are calculated and output based on the captured video signal. Provided is a method for detecting foreign matter in an electric resistance welded tube.

[0010] Preferably, the presence of a foreign substance is detected by counting the number of discriminated wave heights of the captured video signal.

[0011] Preferably, the presence of a foreign substance is detected by subtracting the currently displayed image from the image obtained this time using the captured video signal.

Further, there is provided an electric resistance welded tube characterized in that the above method is used, and the outer surface thereof is laser-marked at a position corresponding to a position where a foreign substance is present.

According to the present invention, a foreign substance such as a burr existing inside an ERW pipe manufactured by a pipe forming and welding process by flowing through an ERW pipe manufacturing line is detected, and its position is displayed on the outer surface of the ERW pipe. An X-ray generator, a CCD camera for photographing an X-ray detection output screen obtained by transmitting X-rays through the ERW pipe, and a storage device for storing the X-ray detection output screen, A detection device for comparing the signals based on the X-ray detection output screen of the CCD camera to detect the presence of a foreign substance;
A laser marking device, a calculating device that calculates and outputs that the ERW tube has reached the position of the laser marking device based on the detection of foreign matter, and a laser that is applied to the outer surface of the ERW tube based on an output value of the calculating device. A foreign object display device in an electric resistance welded tube characterized by performing marking.

Preferably, as the signal based on the X-ray detection output screen, a secondary processing signal based on the screen is used.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an ERW pipe production line. In this figure, in this production line, an ERW pipe production process 100
In addition, a foreign substance presence / absence automatic determination and marking step 101 is performed. As shown in the figure, the electric resistance welded tube manufacturing process is performed by rotating the thin coil 1 and sending it out into a flat plate.
A coil relay section 4 for relaying a coil sent through the small-diameter pipe 3 to a process to be described later; a forming section 6 for gradually rolling the coil by a roller 5 to form a pipe; Weld 8 to be welded by welding machine 7 for welding eyes
A bead removing section 9 for removing a bead generated on a welding line on the outer surface of the pipe, a cooling section 10 for cooling the pipe, and a shaping section 12 for shaping the pipe into a predetermined shape by rollers 11;
A traveling cutting section 1 for cutting a traveling pipe by a cutting machine 13.
And 4. As described above, the ERW tube 15 is cut by the traveling cutting unit 14 into a standard length or a length according to a user's request, but the manufacturing method is well known. No need for explanation.

The ERW pipe 15 that has passed through the ERW pipe manufacturing step 100 is sent to a foreign substance presence determination and marking step 101.
In this step, an X-ray generator 21 and an X-ray detector 22 as X-ray devices, an image processing device 23 which receives the signals and performs image processing, and the presence or absence of foreign matter are determined. An arithmetic unit 24 that performs an operation to generate a marking signal when the existing position comes to the position of a marking device, for example, a laser marking device 25.

FIG. 2 shows the arrangement of the X-ray apparatus viewed from the side, and FIG. 3 shows the arrangement viewed from the upper side.
FIG. 4 shows a front view along the flow direction of the ERW pipe. In these figures, the ERW tube 15 is a series of pedestals 30.
The X-ray generator 21 flows over the roller 31 disposed thereon.
The signal is detected by the imaging intensifier of the X-ray detector 22 by the X-ray irradiation from. That is, an image is formed by changing a signal into light. Reference numeral 32 denotes lighting, and reference numeral 33 denotes a monitoring camera. These devices and equipment are arranged in a shielding box 34 made of concrete. The wiring extends to the negative side through the concrete wall 35 and is connected to the power supply 36 and the power supply 37,
Wave height discrimination device and moving image processing device 3 described later on the other side
8 is connected. Details will be described later.

The arrangement angle of the ERW tube 15 with respect to the X-ray generator 21 can be detected at any angle. An electric resistance welded line speed of 2 m / sec can be adopted.

As shown in FIG. 3, the shielding box 34
Is provided with an inspection door 41, and shielding plates 42 and 43 are provided on both sides of the X-ray generator 21 and the X-ray detector 22.

As shown in FIG. 4, the shielding box 34
A laser marking device 25 is provided outside and downstream.

FIG. 5 shows the processing of the video signal in the ERW pipe,
3 shows a processing block for appropriately performing laser marking. In the drawing, the inside of the ERW tube 15 is formed as an image on the output surface of an image intensifier of an X-ray detector 22 by an X-ray from an X-ray generator 21 in an imaging unit 51, and this image is formed by a high-speed CCD camera 52. Will be taken at This photographing signal is input to the monitor 53 as it is, and the foreign matter 54 is displayed on the screen. Two methods for performing a laser marking operation using a photographing signal will be described.

The first method is a wave height discrimination method. The photographing signal is input to a wave height discriminating circuit 55, the discriminated signal is input to a counting circuit 56, and a signal indicating the result is compared with a set value from a setting device 57 by a comparing circuit 58, and an arithmetic unit (CPU) 59 (corresponding to the arithmetic unit 24 in FIG. 1)
Is used to determine the presence or absence of a foreign substance and calculate its position. If it is determined that “foreign matter is present”, the time until the foreign matter reaches a certain point of the laser marking device 60 is calculated. The time can be calculated very easily from the distance (L) between the detection point and a certain point of the laser marking device and the flow rate of the ERW pipe, and the calculation is easier if L and V are set constant. Becomes When a foreign substance is present, the arrival of the foreign substance is transmitted to the laser marking device 60 in this way, and laser marking is performed on the outer surface of the ERW tube. A signal is also transmitted to the alarm circuit 61, and an alarm is issued. It should be noted that even if laser marking is not performed on the outer surface of the ERW pipe, the ERW pipe NO. Even if the position of a foreign substance is displayed, the foreign substance removing operation can be performed much more easily and easily than the conventional method.

FIG. 6 shows a method of counting the number of wave heights. FIG. 6A shows an X-ray transmission image A at point X ₁ and an X-ray transmission image B at point X ₂ for the ERW tube 15.
Is shown. The foreign matter C is captured in the X-ray transmission image B. Now, as shown in FIG. 2B, an image is taken by a high-speed CCD camera, and a signal is input from the CCD camera to the wave height discrimination circuit 55 for each pixel. In the wave height discrimination circuit 55, a bar graph is formed as shown in FIG. The upper figure is an A image, and the lower figure is a B image. In the A image, the wave heights of the bar graphs are almost constant and bright. On the other hand, in the B image, the X portion in FIG. 7A is represented as a bar graph having a low wave height as the X portion as shown in the figure. When this result is statistically processed, the result is as shown in FIG. In the A image, the statistical result appears only in the high voltage region, and in the B image, the statistical result also appears in the high voltage region. This statistical result is compared with the set value to determine that “there is a foreign substance”, and the arithmetic unit 59 stores the fact and the position (may be time). In this case, since no image processing is performed, there is an advantage that the presence or absence of a foreign substance can be determined by reducing the number of memories.

FIG. 7 shows a flowchart in this case.
In this figure, the end of the foreign substance inspection is determined, and (S10
1) If “No”, go to S102, if “Yes”, end (S106). In S102, the output of the CCD camera is divided into 256 voltages by the wave height discrimination circuit (△
V), count how many voltages (outputs) are input within a predetermined time at each divided voltage ΔV. Next, among the input count numbers for each voltage, has the count number of the voltage corresponding to the contaminant contamination exceeded a predetermined value? Is determined (S1
03). If “No”, the process returns to S102. “Yes”
In the case of (1), an alarm is issued (S104) and the activation of the laser marking device is controlled (S105). Then, the process ends (S106).

The second is an image signal processing method. The captured video signal is A / D converted by the A / D converter 65, and the signal is set in the memory 1 (66) as "the image obtained this time". The noise of this signal is removed by the recursive filter 67, and the signal is set in the memory 2 (68) as the "image after filtering". This signal is supplied to an arithmetic unit (CPU) 70 (corresponding to the arithmetic unit 24 in FIG. 1).
Is input to The “currently displayed image” is output from the CPU 70 to the memory 3 (69). Memory 1 (6
6) and the memory 3 (6)
The arithmetic circuit 71 performs arithmetic processing on the “currently displayed image” signal in 9). The result is compared with the set value from the setting unit 72 by the comparison circuit 73, and the comparison result is input to the CPU 70. Based on the result, the presence of the foreign matter is determined, and similarly to the first method, the activation control of the laser marking device 74 and an alarm by the alarm circuit 75 are issued. The signal from the CPU 70 is D / A converted by a D / A converter 76, and the result is displayed on a monitor display 77 and recorded on a VTR 78.

FIG. 8 shows an X-ray fluoroscopic image as H ₁ at time t ₁ .
Time t _{2 is} designated as H ₂ and time t ₃ is designated as H ₃ . “Bright” indicates a bright image gradation value, and “dark” indicates a dark image. Foreign matter is indicated by C.

The memory 1 and the memory 3 store the presence of foreign matter as shown in FIG. That is, the latest information is stored in the memory 1, and when the information in the memory 2 is subtracted from the memory ₁ , all “zero” displays corresponding to H ₁ and “minus” displays 81 corresponding to H ₂ are displayed. appears, in response to H ₃ "minus" display 81 and "plus" display 82 and a "zero" display 83 appears. The presence of a foreign object is determined by checking whether the data thus subtracted deviates from the set value, is equal to or more than the plus set value, or is equal to or less than the minus set value.

FIG. 9 shows a flowchart in this case.
In this figure, an image formed on the output surface of the X-ray detector image intensifier is photographed by a high-speed CCD camera, and is set in the memory 1 after A / D conversion (S20).
1). Next, the image data in the memory 3 is subtracted from the memory 1 (S202). It is determined whether the subtracted data is out of the set value, is not less than the plus set value, or is not more than the minus set value, and it is determined whether there is a foreign substance (S203). If "Yes", an alarm is issued (S204). In addition, the activation of the laser marking device is controlled (S205). When S203 is “No” and when the next step after S205,
Noise removal is performed by the reactive filter (S20).
6), the value is set in the memory 2 (S207).
At the same time, it is set in the memory 3 and displayed on the monitor (S208). It is determined whether or not to end (S209),
If “Yes”, the process ends, and if “No”, the process returns to step S201.

According to this method, the presence of the foreign matter can be reliably detected.

In these embodiments, a high-speed CCD camera is used, but other photographing devices can be used as appropriate.

[0032]

According to the present invention, even when the ERW pipes flow one after another in the ERW pipe production line,
It is possible to automatically and reliably detect the foreign matter inside the ERW tube, which is a long tube, without requiring labor, and to perform marking on the outer surface of the tube corresponding to the point where the foreign matter exists.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a side view showing a partial configuration of FIG. 1;

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a front view of FIG. 2;

FIG. 5 is a block diagram of an embodiment of the present invention.

FIG. 6 is an explanatory diagram for statistically processing a measurement result.

FIG. 7 is a flowchart.

FIG. 8 is an explanatory diagram for determining the presence of a foreign object based on a measurement result.

FIG. 9 is a flowchart.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Thin coil, 2 ... Uncoil part, 3 ... Small diameter pipe, 4
... Coil relay part, 5 ... Roller, 6 ... Forming part, 7 ... Welding machine, 8 ... Welding part, 9 ... Bead removing part, 10 ... Cooling part, 1
DESCRIPTION OF SYMBOLS 1 ... roller, 12 ... fixed-form part, 13 ... cutting machine, 14 ... travel cutting part, 15 ... ERW pipe, 21 ... X-ray generator, 22 ... X-ray detector, 23 ... Image processing device, 24 ... Computing device , 25 ...
Marking device, 55: Wave height discrimination circuit, 56: Counting circuit, 57: Setting device, 58: Comparison circuit, 59: Computing device (CPU), 60: Laser marking device, 61: Alarm circuit, 65: A / D converter , 66 ... Memory 1, 67 ...
Recursive filter, 68 memory 2, 69 memory 3, 70 arithmetic device (CPU), 71 arithmetic circuit, 72
... setting device, 73 ... comparison circuit, 74 ... laser marking device, 75 ... alarm circuit.

Claims (6)

[Claims] A method for detecting foreign matter such as burrs present inside an ERW pipe manufactured by an ERW pipe manufacturing process by flowing through an ERW pipe manufacturing line. An electric sewing machine characterized by taking an X-ray detection output image obtained by transmitting X-rays through a sewing tube, and calculating and outputting the presence of a foreign substance and the position of the presence in an electric resistance welded tube based on the taken video signal. A method for detecting foreign matter in a pipe. 2. The method for detecting foreign matter in an electric resistance welded tube according to claim 1, wherein the presence of the foreign matter is detected by counting the number of discriminated wave heights of the image signal of the photographed image. 3. The electric resistance welded tube according to claim 1, wherein the presence of a foreign object is detected by subtracting a currently displayed image from an image obtained this time using a captured video signal. Foreign matter detection method. 4. An electric resistance welded tube using the method according to claim 1, wherein the outer surface thereof is laser-marked at a position corresponding to a position where a foreign substance is present. 5. An electric resistance welded pipe which flows through an electric resistance welded pipe production line, detects foreign matter such as burrs present inside the electric resistance welded pipe manufactured by a pipe forming and welding process, and displays the position on the outer surface of the electric resistance welded pipe. An X-ray generator; a CCD camera for photographing an X-ray detection output screen obtained by transmitting an X-ray through an ERW tube; a storage device for storing the X-ray detection output screen; A detection device that detects the presence of a foreign object by comparing signals based on the X-ray detection output screen of the CCD camera; a laser marking device; and the ERW tube reaches the position of the laser marking device based on the detection of the foreign object. A processing device for calculating / outputting the information, and a foreign matter display device in the ERW pipe, which performs laser marking on an outer surface of the ERW pipe based on an output value of the calculation device. 6. The foreign matter display device in an electric resistance welded tube according to claim 5, wherein the signal based on the X-ray detection output screen is a secondary processing signal based on the screen.