JPS63228058A - Electromagnetic ultrasonic wave generating device - Google Patents

Abstract

PURPOSE:To make the generation of an electromagnetic ultrasonic wave constant by running a metallic pipe to be inspected in an annular electromagnetic ultrasonic wave generating coil, blowing compressed air to the entire outer periphery of the metallic pipe, and making the interval between the metallic pipe and coil uniform. CONSTITUTION:The metallic pipe 4 is run in an annular ultrasonic wave transmission part 1. The generating coil 2 is provided to the coil case 3 of the transmission part 1. A gap is formed for the generating coil 2 on the surface of the coil case 3 and plural gaps are provided in the lengthwise direction of the metallic pipe 4. Then the compressed air from the air chamber C in the coil case 3 is blown uniformly from the gaps. Consequently, the coil case 3 and metallic pipe 4 are held at a uniform interval over the entire outer periphery. Consequently, the interval between the metallic pipe and transmission part is made uniform, so the generation efficiency of the electromagnetic ultrasonic wave can be made constant.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is capable of various measurements or inspections of metal pipes as test materials by generating and detecting ultrasonic waves using magnetically induced urine. The present invention relates to an electromagnetic ultrasonic generator that enables.

[Conventional technology]

BACKGROUND ART Conventionally, methods for non-destructive testing of materials include methods in which ultrasonic waves are propagated inside the material and the transmitted waves are detected to perform various planning and inspections.

FIG. 3 shows electromagnetic ultrasonic generation IS in which ultrasonic waves are generated in a so-called mfB induction manner when the object to be inspected is a metal vibrator.

In the same figure, (1) is a charge ultrasonic transmitter (hereinafter referred to as an ultrasonic transmitter).

Simply the transmitter), +2) is the electromagnetic ultrasonic generator coil (hereinafter referred to as "transmitter").

(simply a generating coil), (31 is an insulating case that houses the generating coil (2), and (4) is a metal pipe, and the generating coil (2) is arranged around the outer periphery of the metal pipe. It is formed by winding it into a spiral shape.

To explain in more detail using the figure, when a displacement current I is transmitted from an external transmitter to the generating coil (2), a portion of the metal pipe (41) near the surface of the surface facing the generating coil (2). Due to the interaction between the eddy current I' and the magnetic field BH, a Lorentz force is generated near the surface of the metal pipe (4) facing the generating coil (2), and this Lorentz force F becomes superfluous. The sound waves become sound waves and propagate inside the metal pipe (4).

The generating coil (2) has a spiral shape when it matches the outer diameter of the metal pipe (4), and the generating coil (2) uniformly generates ultrasonic waves near the surface of the metal pipe (4). In order to achieve this, the interval between the generating coil (2) and the metal vibrator (4) must be constant over the entire circumference. This is because the generation efficiency of the eddy electric @ I / and the magnetic field Bi is affected by the distance between the generation coil (2) and the metal pipe.

In other words, it is necessary that the circle corresponding to the outside in the cross section of the metal pipe (41) and the circumference in the cross section of the generating coil (2) form concentric circles.

Incidentally, the generating coil (2) is arranged so that the outer periphery of the metal pipe (4) and the generating coil (2) always form a concentric circle even if there are fluctuations such as vertical movement during the conveyance process of the metal pipe (4). Generally, the following methods were used to make people fall in love.

That is, the vertical fluctuation of the metal pipe (4) during transportation is detected by some means, and the detected amount is detected by the generating coil (2).
That is, it feeds back to the mechanism holding the transmitter (1).

[Problem that the invention seeks to solve]

In the conventional electromagnetic ultrasonic generator, the distance between the outer circumferential surface of the metal pipe and the front r generating coil, that is, the transmitter, is constant over the entire circumference even if there is vertical fluctuation due to conveyance of the metal pipe. In order to make the feed@s follow the metal pipe, all vertical fluctuations of the metal pipe are detected,
Since the method of controlling the holding device '1s of the transmitting section based on the detected amount was used, the following problems occurred. That is, it is necessary to have equipment for detecting vertical fluctuations in conveyance in real time while online, and equipment for controlling holding machine IIIk of the transmitter according to the detected amount.
(a) There was a problem in that the structure of the entire ultrasonic generator was complicated.

This invention was made to solve the above-mentioned problems. Gas is blown out toward the metal pipe from the surface of the transmitter facing the metal pipe, and the pressure of the gas is used to blow out the gas from the surface facing the metal pipe. In order to keep the gas in the air at a certain distance from the metal pipe, even if there is a vertical fluctuation in the conveyance of the metal pipe, the gas is ejected uniformly over the entire inner circumference of the transmitter. The distance between the outer peripheral surface of the pipe and the transmitter can be made equal over the entire circumference.

[Means for solving problems]

The ti ultrasonic generator according to the present invention reduces the distance between the transmitter and the metal pipe to the inner circumference of the transmitter by uniformly blowing gas outward from the inner circumferential surface of the transmitter. Since the distance between the metal pipe and the transmitter is kept constant even if the conveyance of the metal pipe fluctuates up and down, the distance between the metal pipe and the transmitter is always constant, and the electromagnetic energy generated by the transmitter in the metal pipe is The sound wave generation efficiency is made constant over the entire inner circumference of the transmitter.

[Effect]

In this invention, 1! Since the distance between the transmitter that generates magnetic ultrasonic waves and the transmitter is kept constant by blowing gas outward from the inner circumferential surface of the front r transmitter, vertical fluctuations in conveyance are prevented from occurring in the metal pipe. Even so,! The magneto-ultrasonic wave generation efficiency was made constant over the entire inner circumference of the transmitter.

〔Example〕

FIG. 1 is a diagram showing an embodiment of a magneto-ultrasonic generator according to the present invention. In the figure, (1) is a transmitter, (2) is a generating coil, and (3I is a coil case made of an insulator. Furthermore, (4) is a metal pipe that is the material to be inspected. In the figure , the generating coil (2) and the metal vibrator (4) are shown in outline.

The bottom surface of the coil case (3) is the generating coil (2).
It also serves as a bobbin for winding the generator coil (
21ii It is wound in a spiral around the outer periphery of the metal pipe. Therefore, the shape of the transmitter 5 (1) is a pipe, and the extra volume pipe (4) is conveyed inside the transmitter (1).

Moreover, FIG. 2 shows a cross-sectional view of the transmitter (1) when facing the longitudinal force of the metal pipe (4).

That is, in the gap between the generating coils (2) on the surface of the front V coil case (3), there are n pieces in the longitudinal direction of the metal pipe (4) and m pieces in the circumferential direction of the metal pipe (4), in total. m
Xn slots) H11~Machi□ are uniformly provided.

The slot HH~) Imnd front case (3)
It communicates with the gas qc provided inside. Furthermore, the gas chamber C communicates with an external compressed air supply source (not shown). That is, by blowing compressed air outward from the slots H1 to Hmn through the gas chamber C, the coil case (3) can be held entirely outside the metal pipe (4) and suspended. Further, since the slots) U11 to Hmn are uniformly provided on the surface of the coil case (31), compressed air can be uniformly blown out from the surface of the coil case (3),
The distance between the metal pipe (4) and the coil case (3) can be maintained over the entire outer circumference of the metal pipe.

On the other hand, the principle of generating 11-magnetic ultrasonic waves is as explained in the prior art section. It is necessary to generate the eddy current ' and the magnetic field gi equally over the outer peripheral surface of the metal pipe (4), that is, in order to do so, the eddy current @
As described above, the magnetic field ni decreases as the distance between the generating coil (2) and the metal pipe (4) increases. It is necessary to protect the entire outer circumference of the vibrator (4) and keep it constant.

Therefore, according to the present invention, the metal pipe (4) Km
Even if the feed rate fluctuates up and down, the metal pipe (4) is always
1 and the transmitting section (1) can be maintained over the entire circumference, the generating coil ( 2
) makes it possible to keep the 1m electromagnetic ultrasonic generation efficiency constant.

In this embodiment, compressed air is used as the compressed gas blown out from the coil case (3), but it goes without saying that other gases can also have the same effect.

〔Effect of the invention〕

As described above, according to the present invention, in order to make a pipe-shaped transmitting section through which a metal pipe passes through a metal pipe that has conventionally been subject to vertical fluctuations in conveyance, the amount of fluctuation in vertical fluctuations is detected and detected. Because the method used was to feed back the amount of gas to the transmitter, the device as a whole would be complicated to detect up and down changes online in real time. Since we use a method that uniformly blows air from the outer circumferential surface of the metal pipe to the outer circumferential surface of the metal pipe, even if the feed rate fluctuates up and down, the compressed gas always maintains the distance between the outer circumferential surface of the metal pipe and the transmitting section to the entire inner circumference of the transmitting section. Since the transition is constant, there is an effect that the generation efficiency of electromagnetic ultrasonic waves is also constant.

[Brief explanation of drawings]

FIG. 1 shows an electromagnetic ultrasonic generator f according to an embodiment of the present invention.
Fig. 2 is a diagram showing a cross section of a magnetic ultrasonic transmitter that shows the features of the present invention, Fig. 2 is a diagram showing a conventional electromagnetic ultrasonic generator, and (1) is a diagram showing a conventional electromagnetic ultrasonic generator. A sound wave transmitter, (2) is an electromagnetic ultrasonic wave generating coil, (3) is a coil case, (11~)fmn Haslot C is a gas chamber. In FIG. 9, the same or corresponding parts are designated by the same reference numerals.

Claims (1)

[Claims] A helical coil is sized to allow the metal pipe to pass through it, and is wound in a spiral around the outer circumference of the metal pipe, and the helical coil is fixed and fixed. In an electromagnetic ultrasonic generator having a transmitter made of a holding case, a gas chamber provided uniformly over the entire circumference of a surface of the coil case facing the metal pipe and provided inside the coil case. An electromagnetic ultrasonic generator comprising a plurality of slots for ejecting compressed gas stored in the coil case from the inner peripheral surface of the coil case toward the surface of the metal pipe.