KR20190037480A - Eddy-current probe device - Google Patents

Abstract

Provided in the present invention is an eddy-current probe device. The eddy-current probe device comprises: a device body unit; a wedge unit disposed at an upper end of the device body unit; and a measuring unit having a flexible substrate disposed at an upper end of the wedge unit, and having a coil measuring an eddy current of a target object to be measured, and a pair of substrate connectors connected to both ends of the flexible substrate so as to be disposed at both side portions of the device body unit; and a lower connector disposed at a lower end of the device body unit, and electrically connected to the pair of substrate connectors, and transmitting the measured eddy current to the outside.

Description

[0001] EDDY-CURRENT PROBE DEVICE [0002]

The present invention relates to an eddy current probe apparatus, and more particularly, to an eddy current probe apparatus using a flexible substrate and measuring eddy current by replacing a wedge corresponding to a shape of an object to be measured.

Generally, since the turbine rotates at a high speed under high temperature and high pressure, there is a high possibility of occurrence of defects such as embrittlement, stress corrosion, and corrosion fatigue in a blade, a rotor, or a disc during a long operation.

Among them, turbine blades are damaged by a wide variety of causes. Most blade breakage cases occur most frequently in the last stage blade (LSB) called L-0.

There are many ways to design the roots to be assembled with the blades and rotors, but most of the typical LSB applications are axial-entry fir-tree root and finned finger root. Axial-entry fir-tree root assembly method generally has a problem that cracks are generated at the blade root region due to stress corrosion cracking (SCC) and fatigue.

In order to examine this, a nondestructive inspection method was conventionally used.

This is because the visual inspection (VT), liquid penetration inspection (PT) and magnetic particle inspection (MT) are mainly performed after the blade is disassembled. However, in this case, detection of a minute defect such as fatigue crack at the root of the blade There is a difficult problem.

Among the general surface nondestructive inspection, the surface inspection of PT, MT, etc. records the result as a sketch, a photograph, etc., and the dependency on the inspector is high and the inspection speed is slow. There is a problem that affects the < / RTI >

Therefore, relatively eddy current test (ECT, ECA) is capable of recording and analyzing through a storage medium, knowing the depth of defect, low dependence of the inspector, and fast inspection speed.

In such an eddy current test, an eddy current is generated on the surface of the coil when the coil through which the alternating current flows is brought close to the conductor, which is a conductor.

This is because the eddy currents flowing in the test specimen change when there are defects such as the conductivity and the permeability of the specimen, the size and shape of the specimen, the shape and size of the coil, the distance between the coil and the specimen,

Thus, by observing the above changes, it is possible to detect the presence or absence of defects existing in the test object, the change of the material, and the like by detecting changes in the phase and magnitude of the eddy current signal received by the coil (probe).

In particular, one absolute coil inspection method in surface inspection has been used as the most suitable inspection method for defect inspection of non-magnetic materials such as stainless steel, defects such as surface corrosion and turbine blades.

FIG. 1 is a diagram showing a conventional eddy current inspection method. 2 is a graph showing the resolution in accordance with the conventional number of coils and arrangement.

As shown in Figs. 1 (a) and 2 (a), a plurality of coils are arrayed as shown in Fig. 2 (b) (ECA), it can be concluded that ECA can simultaneously test large areas with high resolution.

In the inspection with an eddy current, a test using one absolute coil can not indicate the position of a defect in the subject.

On the other hand, the ECA (array eddy current) test arranges a plurality of coil sensors to inspect the region of interest at a time, so that the exact position and result of the defect can be confirmed in three dimensions.

However, the conventional various eddy current testing apparatuses are limited or limited to specific measurement objects, and the measurement unit for measuring the eddy current also has a limited shape, so that it is possible to stably measure eddy currents in various shapes of electronic parts There is a problem that can not be done.

Prior art related to the present invention is Korean Registered Patent Registration No. 10-1327377, and the prior art discloses a probe card assembly using a flexible printed circuit board.

It is an object of the present invention to provide an eddy current probe device capable of permitting a flexible substrate to be easily placed at a measurement position and replacing a wedge portion corresponding to the shape of a measurement object, .

In order to achieve the above object, the present invention provides an eddy current probe apparatus.

The eddy current probe apparatus includes: a device body portion; A wedge portion disposed at an upper end of the apparatus body portion; A measuring unit disposed at an upper end of the wedge portion and having a coil for measuring an eddy current of the measurement object and a pair of substrate connectors connected to both ends of the flexible substrate and disposed at both sides of the device body; And a lower connector which is disposed at the lower end of the apparatus body portion, is electrically connected to the pair of board connectors, and transmits the measured eddy current to the outside.

The wedge portion is replaceable at the top of the device body portion.

It is preferable that the coils are arranged in a multi-array pattern on the flexible substrate.

It is preferable that the pair of board connectors are connected to both ends of the flexible board and are disposed on both sides of the flexible board as the flexible board is bent.

The wedge portion may include a support body and a wedge body formed at an upper end of the support body.

Wherein the wedge body comprises: And is formed so as to correspond to the shape of the measurement region of the measurement object.

The tip of the wedge body is preferably formed into a sharp shape, a shape having a curvature, or a polygonal shape.

The wedge portion is preferably formed of an elastic material.

And a pair of auxiliary wedge portions are formed on both sides of the insertion groove, and the shape of the wedge body and the auxiliary wedge portion are formed on both sides of the insertion groove, It is preferable that they are formed in the same shape.

And a probe guide member is detachably mounted on the upper end of the apparatus body.

It is preferable that the probe guide member is provided at front and rear sides of the wedge portion and additionally supports a measurement position of the flexible substrate supported by the wedge portion in a measurement region of the measurement object.

It is preferable that the probe guide member is formed in a shape corresponding to a shape of another measurement region formed near the measurement region of the measurement object.

The present invention has the effect of permitting the flexible substrate to be easily placed at the measurement position by using the flexible substrate and permitting the eddy current to be used for measurement by replacing the wedge portion corresponding to the shape of the measurement object.

Further, the present invention has the effect of shortening the inspection speed and time because it inspects a large area once through the multiple coil arrangement as compared with the method of inspecting with one absolute coil.

Further, the present invention has an effect that the coils are composed of multiple arrays and the resolution is improved during the inspection

In addition, since the present invention can manufacture only a wedge according to the dovetail shape and replace it if necessary, it is possible to reduce the cost.

FIG. 1 is a diagram showing a conventional eddy current inspection method.
2 is a graph showing the resolution in accordance with the conventional number of coils and arrangement.
3 is an assembled perspective view showing a configuration of an eddy current probe apparatus according to the present invention.
4 is an exploded perspective view showing a configuration of an eddy current probe apparatus according to the present invention.
5 is a perspective view showing various examples of the wedge portion according to the present invention.
6 is a perspective view showing a measuring unit according to the present invention.
7 is a plan view showing the arrangement of coils formed on the flexible substrate of FIG.
8 is a perspective view showing a state before the measurement unit according to the present invention is positioned at the top of the body of the apparatus.
9 is a perspective view showing a probe guide member according to the present invention.
10 is a perspective view showing a state in which the probe guide member according to the present invention is disposed on the blade.
11A and 11B are views showing a process in which the wedge portion of the eddy current probe device of the present invention is disposed in the groove of the blade.
FIGS. 12A and 12B are views showing a process in which probe guide members are disposed above and below the device body of FIGS. 11A and 11B.
13A is a photograph showing an object to be measured according to the present invention.
13B is a photograph showing a test piece relative to the blade.
14 is a graph showing an eddy current test signal collected by a FF-ECA probe on a calibration test piece.
15 is a view showing an inspection signal of the FF-ECA probe for artificial defects of the blade Dovetail.
Fig. 16 is a view showing the result of inspection of an actual blade defect free region.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings so that those skilled in the art can easily carry out the present invention.

The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

Hereinafter, the term "an upper (or lower)" or a "top (or lower)" of the substrate means that any structure is disposed or arranged in any manner, as long as any structure is provided or disposed in contact with the upper surface .

Furthermore, the present invention is not limited to a configuration that does not include any other configuration between the substrate and any configuration provided or disposed on (or under) the substrate.

Hereinafter, an eddy current probe device of the present invention will be described with reference to the accompanying drawings.

3 is an assembled perspective view showing a configuration of an eddy current probe apparatus according to the present invention. 4 is an exploded perspective view showing a configuration of an eddy current probe apparatus according to the present invention.

3 and 4, the eddy current probe apparatus of the present invention comprises a device body part 100, a wedge part 200, a measuring part 300, and a lower connector 400.

Each of the above configurations will be described.

In the device body 100,

An insertion groove 110 is formed at the upper end of the apparatus body 100 according to the present invention. The insertion groove 110 is used as a groove in which the wedge part 200 is mounted.

Both side portions of the apparatus body 100 are formed to pass through.

In the lower portion of the apparatus body 100, the lower connector 400 is mounted.

In addition, an auxiliary wedge portion 120 is formed at an upper end of the apparatus body 100. The auxiliary wedge portions 120 are formed as a pair and are disposed on both sides of the insertion groove 110 and protrude upward.

Here, the pair of auxiliary wedge portions 120 may be formed substantially in the same shape as that of the wedge portion 200.

The wedge portion (200)

The wedge portion 200 according to the present invention is disposed at the upper end of the apparatus body portion 100.

The wedge part 200 may include a support body 210 and a wedge body 220 formed at the upper end of the support body 210.

The wedge body 220 is formed to correspond to the shape of the measurement region of the measurement object.

The measurement object may be a Root dovetail and a blade dovetail of a disc wheel wheel and has a serration or triangular or conical measurement area of the curved surface of the measurement object.

The support body 210 is inserted into and fixed to the insertion groove 110 of the apparatus body 100.

The wedge body 220 is a body directly contacting the measurement region of the measurement object in a state of protruding from the upper end of the apparatus body portion.

Here, the wedge part 200 according to the present invention is formed of an elastic material such as rubber, and can be easily contacted in a measurement area without breakage through a certain elasticity.

5 is a perspective view showing various examples of the wedge portion according to the present invention.

5 (a) to 5 (b), the tip of the wedge body 220 may have a pointed shape, a curved shape, or a polygonal shape.

Thus, the wedges 200, 201, 202, 203 according to the present invention are detachable at the top of the device body so as to use the wedge members 220, 221, 222, 223 corresponding to the shape of the measurement area of the measurement object,

The measuring unit 300 includes:

6 is a perspective view showing a measuring unit according to the present invention. 7 is a plan view showing the arrangement of coils formed on the flexible substrate of FIG.

Referring to FIG. 6, the measuring unit 300 according to the present invention may be positioned above the wedge portion 200.

The measurement unit 300 includes a flexible substrate 310 disposed at an upper end of the wedge unit 200 and having a coil 311 for measuring an eddy current of the measurement object, And a pair of board connectors 320 disposed on both side portions of the apparatus main body 100.

As shown in FIG. 7, the coils 311 are arranged on the flexible substrate 310 in a multi-array pattern.

The pair of board connectors 320 may be connected to both ends of the flexible board 310 and may be disposed on both sides of the flexible board 310 as the flexible board 310 is bent.

Here, a pair of inner covers 130 are disposed on both sides of the apparatus body 100.

The pair of inner covers 130 provide an area where the pair of board connectors 320 to be bent as described above are fixed, and they are engaged and fixed by the fastening bolts B. [

A pair of outer covers 140 are disposed outside the pair of board connectors 320.

The pair of outer covers 140 are fixed to both sides of the apparatus body 100 to cover and fix the pair of board connectors 320 from the outside.

The lower connector 400,

The lower connector 400 according to the present invention is coupled to the lower portion of the device body 100.

The lower connector 400 may be electrically connected to a pair of board connectors 320 fixed to both side portions of the apparatus body 100.

Therefore, the lower connector 400 can transmit the eddy current of the measurement object measured from the measurement unit 300 to the outside.

Next, a process of measuring an eddy current of a measurement object using the eddy current probe apparatus of the present invention will be described.

8 is a perspective view showing a state before the measurement unit according to the present invention is positioned at the top of the body of the apparatus.

8, the wedge portion 200 is mounted on the upper end of the apparatus body portion 100, and the measurement portion 300 is disposed on the upper end of the wedge portion 200. As shown in FIG.

The flexible board 310 is closely attached to the outer surface of the wedge body 220 and the pair of board connectors 320 connected to both ends of the flexible board 310 are disposed on both sides of the apparatus body 100.

Next, a process of arranging and measuring the eddy current probe apparatus on a measurement object using the probe guide member according to the present invention will be described.

9 is a perspective view showing a probe guide member according to the present invention.

9, the structure of the probe guide member 500 according to the present invention will be described.

A probe guide member 500 is detachably mounted on the upper end of the apparatus body 100.

The probe guide member 500 is disposed on the front and rear sides of the wedge part 200 and supports the measurement position of the flexible substrate 310 supported by the wedge part 200 in the measuring area of the measurement object, can do.

The tip 510 of the probe guide member 500 may be formed in a shape corresponding to the shape of another measurement region formed near the measurement region of the measurement object.

10 is a perspective view showing a state in which the probe guide member according to the present invention is disposed on the blade.

Referring to FIG. 10, the procedure of installing the probe guide member 500 will be described.

10, when the measurement object 10 is a blade, the probe guide members 500 are formed as a pair and are formed in a shape corresponding to the shape of the groove 11, which is a measurement region of the blade, Are arranged on the upper and lower sides in the groove 11 which is the measurement area.

Here, the device body 100 according to the present invention may be disposed between the pair of probe guide members 500.

A process of measuring an eddy current of a measurement object using the eddy current probe apparatus having the above configuration will be described.

11A and 11B are views showing a process in which the wedge portion of the eddy current probe device of the present invention is disposed in the groove of the blade.

Referring to Figs. 11A and 11B, the measurement object 10 may be a blade. The blades are formed with a plurality of rows of healds 11, and the grooves 11 correspond to a measurement area.

The device body portion 100 according to the present invention is disposed in any one of the grooves 11. That is, the wedge body 220 of the wedge part 200 mounted on the apparatus body part 100 is fitted in the groove 11 corresponding to the wedge part 200.

The flexible substrate 310, which is in close contact with the outer surface of the wedge body 220, is fitted into the groove 11 to be closely attached thereto. At this time, the wedge body 220 is made elastic so that the inner surface of the groove 11 has elasticity and can be elastically contacted.

Therefore, the coils 311 formed in multiple arrangements in the flexible substrate 310 are brought into close contact with many positions on the inner circumferential surface of the grooves 11 of the blades so that eddy currents can be measured.

FIGS. 12A and 12B are views showing a process in which probe guide members are disposed above and below the device body of FIGS. 11A and 11B.

12A and 12B, a pair of probe guide members 500 are disposed on upper and lower portions of the apparatus body 100, respectively.

That is, since the tip 510 of each of the probe guide members 500 is formed in a shape corresponding to the shape of the blade groove 11, the tip of the apparatus body 100 at the upper and lower positions of the apparatus body 100 And can be guided so as to be movable along the direction of the support and groove (11).

Thus, the measurement unit 300 according to the present invention can measure the eddy current while moving while being guided by the pair of probe guide members 500. Then, the measured eddy current is transmitted to the lower connector 400 through the board connector 320, which can be transmitted to the external device and analyzed.

13A is a photograph showing a test piece or an object to be measured in which grooves corresponding to the shape of the Dovetail Serration are used as calibration test pieces, and a human defect is inserted into the defect depth by the EDM in each defect depth.

FIG. 14 is a graph showing the depth of each defect is displayed as a three-dimensional solid shape as a result of testing a test piece using the eddy current probe apparatus of the present invention.

As shown in FIG. 13B, artificial defects were machined into the dovetail blades 10 by EDM to obtain inspection results as shown in FIG. 15. As a result, the sensitivity and resolution of defects were increased to 0.5 mm in depth.

As shown in Fig. 16, it can be seen that the inspection result signal on the blade 10 of the dovetail without defects is totally clean on the screen.

Accordingly, in the present invention, by using the eddy current inspection of the multiple coil arrangement for detecting defects on the surface in the measurement region of the measurement object, it is possible to provide a large amount of inspection information to the extent that the inspectors and the non- have.

This has the advantage of ECA testing, which allows a large area at one time to remain high resolution and to be inspected quickly.

According to the above structure and operation, the present invention has the effect of shortening the inspection speed and time because it inspects a large area once through the multiple coil arrangement compared to the method of inspecting with one absolute coil.

Further, since the coils are constituted of multiple arrays, the resolution can be improved at the time of inspection.

In addition, since the present invention forms a film-like ECA probe configuration, it is easy to mold to conform to a curved shape, so that a molding can be manufactured in accordance with the dovetail serum of a blade to be inspected, .

Further, since the present invention can manufacture only the wedge part in conformity with the dovetail shape and replace it if necessary, it is possible to reduce the cost.

In addition, the present invention further includes a probe guide member to prevent tilting at the dovetail test, so that a certain signal can be reliably collected at the time of inspection.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Therefore, the scope of the present invention should not be limited to the embodiments described, but should be determined by the equivalents of the claims and the claims.

It is to be understood that the foregoing embodiments are illustrative and not restrictive in all respects and that the scope of the present invention is indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

100:
110: insertion groove
120: auxiliary wedge portion
130: Inner cover
140: outer cover
200: Wedge portion
210: Support body
220: wedge body
300:
310: flexible substrate
311: Coil
320: Board connector
400: lower connector
500: probe guide member

Claims (9)

A device body portion;
A wedge portion disposed at an upper end of the apparatus body portion;
A measuring unit disposed at an upper end of the wedge portion and having a coil for measuring an eddy current of the measurement object and a pair of substrate connectors connected to both ends of the flexible substrate and disposed at both sides of the device body; And
And a lower connector which is disposed at a lower end of the apparatus main body and is electrically connected to the pair of board connectors and transmits the measured eddy current to the outside,
Wherein the wedge portion is replaceable at an upper end of the device body portion.
The method according to claim 1,
Wherein:
Wherein the flexible substrate is arranged in a multi-array pattern.
3. The method of claim 2,
Wherein the pair of board connectors include:
Wherein the flexible substrate is connected to both ends of the flexible substrate and is disposed on both sides of the device body as the flexible substrate is bent.
The method according to claim 1,
The wedge portion
And a wedge body formed at an upper end of the support body,
Wherein the wedge body comprises:
Wherein the eddy current probe device is formed to correspond to a shape of a measurement area of the measurement object.
5. The method of claim 4,
The tip of the wedge body
Wherein the eddy current probe device is formed in a sharp or curved shape or a polygonal shape.
The method according to claim 1,
The wedge portion
Wherein the eddy current probe device is formed of an elastic material.
5. The method of claim 4,
At the upper end of the apparatus body portion,
An insertion groove into which the support body is inserted, and a pair of auxiliary wedge portions,
Wherein the pair of auxiliary wedge portions are formed on both sides of the insertion groove,
Wherein the wedge body is formed in the same shape as the shape of the wedge body.
5. The method of claim 4,
A probe guide member is detachably mounted on an upper end of the apparatus body,
Wherein the probe guide member comprises:
Wherein the measuring position of the flexible substrate is supported by the wedge portion in a measuring region of the measurement object, the measurement position of the eddy current probe being supported on the front and rear sides of the wedge portion.
8. The method of claim 7,
Wherein the probe guide member comprises:
Wherein the shape of the eddy current probe is formed in a shape corresponding to a shape of another measurement area formed in the vicinity of the measurement area of the measurement object.

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