JPS60168046A - Electromagnetic induction testing device - Google Patents

Abstract

PURPOSE:To execute with a high accuracy a state inspection by connecting an impedance variation compensating electric conductor to a standard coil and winding it up in the same way as an electric conductor connected to a detecting coil, in order to compensate an impedance variation caused by a winding of the electric conductor connected to the detecting coil. CONSTITUTION:A detecting coil 2 is inserted into a pipe 5 of an object and inspected extending over the overall length. A cable 18 and an electric conductor 19 are wound to a winding reel 30 by a portion equal to a length of the steel pipe 5. An impedance between an input terminal 40b and a detecting terminal 40a, detected by a bridge circuit becomes the sum of Imp. of the adjustment time and Imp. of the winding time, if electromagnetic characteristics of a standard steel pipe 1 and the steel pipe 5 are the same. On the other hand, Imp. between the input terminal 40b and a detecting terminal 40c becomes the sum of Imp. of the adjustment time of a standard coil 3 and Imp. of a winding part 29, a relation of DELTAomegaL2=DELTAomegaL3 is formed, and a balance of the bridge circuit is kept. In this way, an inspection of a quality of material and a state of the inside surface of a pipe material is executed with a high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electromagnetic BP for inspecting the material and properties of the inner surface of a pipe material.
With regard to conduction testing equipment, the present invention particularly proposes an electromagnetic induction testing equipment that eliminates the adverse effects on testing accuracy caused by scanning of detection coils and can perform tests with high accuracy.

[Prior art]

There is a method of inspecting properties such as the hardness of the inner surface of a steel pipe, the material of carbon-containing ports, local physical property irregularities, the presence of impurities, the presence or absence of flaws, and their depth using 7tj magnetic induction. The principle of this method is that the impedance of the detection coil inserted into the steel pipe is the same as the impedance of the detection coil inserted into the steel pipe. By utilizing the fact that the impedance changes due to fluctuations in conductivity and detecting the change in impedance, the purpose is to test the material and properties of the tonal inner surface that has a correlation with magnetic permeability 1 and electric current ratio. .

The following devices are known as devices that utilize this principle to specifically inspect the A quality and properties of the inner surface of steel pipes.

That is, as shown in FIG. 1, a short standard steel pipe of known material 1.
■Detection coil consisting of a multi-layer coil inside 2. Insert the standard coils 3 respectively. The detection coil 2 and the coil 3 connected to the marker 2 are connected to an electromagnetic induction tester 4 consisting of an oscillator that energizes an alternating current ffi current, a bridge circuit that measures the impedance of both coils, etc., and cables 8a and 8b.
connected via.

In such a configuration, an alternating current is applied to the detection coil 2 and the standard coil 3 from the oscillator, and the adjustment is performed so as to balance the 1/8th of the burr and nozzle times. Thereafter, as shown in FIG. 2, the detection coil 2 is inserted into the steel pipe 5 to be inspected and scanned from one end to the other end. 2 (In this scanning, the cylindrical detection coil support member 7 with the detection coil 2 at the tip (=t i) is inserted into the steel pipe 5 by the feed roller 20, and
This is done by winding up the support member 7 containing the cable 8a with the take-up reel 30.

Therefore, the detection coil 2. When 4 AC is applied to the standard coil 3, if the material or property of the standard steel pipe 1 and the quality or property of the steel pipe 50 to be inspected are different, the bridge circuit detects an unbalanced amount of impedance corresponding to this difference. Thereby, the material and properties of the steel pipe 50 can be inspected (determined) based on the correlation between the preset amount of impedance deviation and the material or properties of the steel pipe 5.

Now, in such a device, when the detection coil 2 is located at the proximal end Q of the steel pipe 5, the detection coil support member 7 and the cable 8a are wound up, and an impedance change is formed there. Therefore, if the electromagnetic characteristics, materials, and properties of the steel pipe 1 and the steel pipe 5 are similar, the impedance of the side including the detection coil of the bridge circuit is the same as the impedance ωL2 during adjustment of the detection coil 2. The sum of the impedance change Δω1 and 2 of the take-up part, i.e. ωL2 +Δω
It becomes I-2. When adjusting the impedance QL3 of the standard coil 3, for example, ωL, 2=ωL3,
In this device, ωL2+ΔωI-2≠ωl, 3,
Mark (!' Steel pipe point Even if the steel pipe 5 is the same, the bridge circuit becomes unbalanced due to the change in impedance of the winding section. In such a state, changes occur in the material and properties of the steel pipe 5. For example, when inspecting a portion where impurities are present, the impedance complaint i!jW detected by the bridge circuit includes an error due to impedance change at the winding section, and and mark'/$
41 quality and properties of the steel pipe 1 cannot be evaluated correctly, and therefore accurate inspection cannot be performed.

c. Purpose] The present invention has been made in view of the above circumstances, and in order to compensate for impedance fluctuations due to winding of a conductor connected to a detection coil, an impedance fluctuation compensation conductor is connected to a standard coil. By winding it in the same way as the conductor connected to the detection coil, the Toga on the inner surface of the pipe material,
We offer an electromagnetic induction testing device that can perform property inspections with high accuracy (J
(The purpose is to

[Structure of the invention]

The tortoise angle induction testing device according to the present invention is designed to wind up the extra long bone of the conductor that is connected to the detection coil which is inserted into the tube of a medical examiner and scans the inside of the tube. Comparing the impedance with the impedance of a standard coil inserted into the pipe material, the impedance due to the winding of the conductor connected to the detection coil is In order to compensate for fluctuations, the present invention is characterized in that an impedance fluctuation compensation conductor is wound around the standard coil in the same manner as the conductor connected to the detection coil.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings showing the embodiments thereof. FIG. 3 is a schematic side view of the electromagnetic induction testing apparatus according to the present invention, and FIG. 4 is a circuit diagram of the electric circuit thereof, without showing the electric circuit.

The difference between the conventional device shown in FIGS. 1 and 2 and the device of the present invention is that an impedance fluctuation compensation conductor 19 is connected to the side of the bridge circuit that includes the reference coil 3. As shown in FIG. 3, multi-layer winding detection = 1 coil 2 is formed in the groove on the circumference of the cylindrical coil bobbin 6. The cylinder bobbin 6 is attached concentrically to the tip of the long cylindrical detection handle 91 (moon 7).

The support member 7 is a flexible hard resin tube and has a built-in conductor I9 for the impedance variable sleeve 119 to be connected to the cable 1B connected to the detection coil 2 and the standard coil 3, and the support member L7 It is adapted to be wound up by a winding wheel 30 installed at a position ia distance apart from the proximal end side of the winding 17. In addition, support members 7 to 8 are
A feed l:J-ra 20 is installed between the steel tubes 30 and the support member 7 can be inserted into the steel pipe 1. The tip of the conductor 19 is fixed to the tip of the support member 7 by an appropriate method. From the proximal end of cable 18, its inner conductor 18
A, 18b are exposed to form one side of the bridge circuit, and the detection terminal 40a and input terminal 4 of the electromagnetic induction tester 4 are exposed.
It is connected to 0b. Similarly, from the base 0111 portion of the conductor 19, the internal conductor 19a is formed.

19b is exposed, and the conductor 19a is connected to the input terminal 40b of the electromagnetic 8f:j tester 4. conductor 191
1 is connected to one end of the standard coil 3 to be inserted into the standard steel pipe 1, and the other end of the detection = 1 coil 3 is connected to the electromagnetic induction tester 4.
It is connected to the detection terminal 40c of. That is, standard coil 3
and the conductor 19 form the other side of the bridge circuit.

Next, when inspecting the material and properties of the steel pipe 5 using the apparatus of the present invention having such a configuration, the following will be explained.

First, the detection coil 2 is inserted into the standard steel layer 1 which is fixed at a predetermined position as shown in FIG. Then, the detection coil 2 and similar 4Fj
;ll + mark inserted into steel pipe 1! A high frequency current of about 50011z is applied to the coil 3 from the oscillator of the electromagnetic induction tester 4. Then, the bridge circuit of the tester 4 is adjusted to balance the bridge.

Next, the detection coil 2 is removed from the marker I41i steel tube 1, inserted into the steel pipe 5 to be inspected as shown in FIG.
The inspection will be carried out over the entire length of the 5.

In such an inspection, when the detection coil 2 is located near the proximal end of the steel pipe 5, the cable 18 and the conductor 19 are wound around the take-up reel 30 by an amount approximately equal to the length of the steel pipe 5. As a result, winding portions 28 and 29 as shown in FIG. 4 are formed on the winding rule 30. In this case, the impedance between the input terminal 40b and the detection terminal 40a detected by the bridge circuit is determined by the adjustment of the detection coil 2 when the standard steel pipe 1 and the steel pipe 5 have similar electromagnetic characteristics or material 1 properties. The impedance ωL of
2 and the impedance ΔωL2 of the winding section 28, that is, ωI2. +ΔωL2.

On the other hand, the impedance between the input terminal 40b and the detection product 1 child 40c is the impedance ωL when adjusting the standard coil 3,
] and the impedance of the winding section 29 80] L3,
Immediately, it becomes ωL3+ΔωL3. Therefore, input terminal 40b
- impedance between the detection terminal 40a and the input terminal 40 [
) to the detection terminal 40c is the unbalanced amount of impedance (
ωL2+ΔωI−,2) (ω[7]→−ΔωL3). By the way, since the cable 18 and the conductor 19 are wound with approximately the same length, the impedance of the winding r; ] holds true.

Further, at the time of adjustment, a certain relationship, for example, ωL2-ωL3, is established between ωL, ] and Q month −2. Therefore, in this case 1. ;I: (,)kawa, 2+Δω1-2
．． C)-(ωL, 3 →-ΔωL3)=O, and the balance of the bridge circuit is maintained.

Therefore, when inspecting a portion of the steel pipe 5 whose electromagnetic characteristics, material, and properties are different from those of the standard steel pipe 1, it is possible to accurately detect the impedance unbalance amount corresponding to the difference. A good test can be done.

〔effect〕

As detailed above, the electromagnetic induction test device according to the present invention connects the impedance variation compensation conductor to the standard coil and connects it to the detection coil in order to compensate for impedance variation due to winding of the conductor connected to the detection coil. Since it is configured to be wound up in the same manner as the continuous conductor, the present invention has excellent effects such as being able to accurately inspect the quality and properties of the inner surface of the tube material.

In the two series of embodiments, the present invention is applied to the inspection of the material and properties of the inner surface of a steel pipe, but it goes without saying that the invention can also be applied to the inspection of the inner surface of other metal pipes.

[Brief explanation of drawings]

1.2 is a schematic side view of the conventional device, FIG. 3 is a schematic side view of the device of the present invention, and FIG. 4 is a circuit diagram schematically showing the electric circuit thereof. ■... Standard steel T [2... Detection coil 3... Standard coil 4... Electromagnetic induction tester 5... Steel pipe 7.
...detection coil support member 1) (...cable 19)
... Conductor patent for impedance fluctuation compensation Applicant Sumitomo Kinku Industries Co., Ltd. Agent Patent attorney 11σ Noboruto

Claims (1)

[Claims] 1. The extra length of the conductor connected to the detection coil inserted into the tube to be inspected and scanned inside the tube is wound up, and the impedance of the detection coil and the length of the conductor inserted into the standard tube material are determined. In an electromagnetic induction testing device that inspects the inner surface of the tube material by comparing the impedance of the standard coil with the impedance of the standard coil, the standard coil is provided with an impedance variation sleeve IjK in order to compensate for impedance variation due to winding of the conductor connected to the detection coil. An electrical induction testing device characterized in that it is configured to connect a conductor for impedance variation compensation (jλ) and wind the i-body in the same manner as the conductor connected to the detection coil.