WO2012021034A2

WO2012021034A2 - Conductor thickness detecting device using a double core

Info

Publication number: WO2012021034A2
Application number: PCT/KR2011/005962
Authority: WO
Inventors: 박덕근; 정용무; 김흥회
Original assignee: 한국원자력연구원
Priority date: 2010-08-12
Filing date: 2011-08-12
Publication date: 2012-02-16
Also published as: KR20120015566A; WO2012021034A3; KR101254300B1

Abstract

According to the present invention, a duct thinning detecting device using a double core is devised so as to evaluate corrosion or changes in thickness (thinning) caused by corrosion of a duct which is covered by an insulator, which is to say losses in the duct, from outside the insulator by using eddy currents by means of a differential probe having a double core without dismantling the insulator in non-destructive testing. More specifically, the present invention comprises: a probe unit having a double core, a drive coil and a differential Hall sensor; a pulse-generating unit which is connected to the probe unit and generates a wide-band pulse voltage that is applied to the drive coil; an amplification unit which is connected to the probe unit and amplifies a measurement signal induced in the Hall sensor; an A/D conversion unit which is connected to the amplification unit and converts the measurement signal to a digital signal; and a control unit which is adapted to control the probe unit, the pulse-generating unit, the amplification unit and the A/D conversion unit while at the same time storing and displaying the digital signal.

Description

【Specification】

[Name of invention]

Conductor thickness flaw detector using double core

Technical Field

<ι> The present invention provides a conductor thickness flaw detector, which doubles the core of a probe portion, thereby increasing the sensitivity of the flaw detector by increasing the sensitivity of the flaw detector without increasing the size of the core and at the low current. Concerning conductor thickness flaw detectors.

<2>

Background Art

<3> In general, in the case of transferring high temperature fluids, the pipes are protected by an insulator (insulating material) to prevent heat loss.

In this case, however, the insulation must be dismantled in order to inspect the pipe for damage due to corrosion or reduction in thickness of the pipe underneath the insulation.

<5>

<6> Although the pill eddy current technique is used to inspect the corrosion of the pipe without dismantling the insulator, the farther the distance between the object and the probe is, the stronger the magnetic field is, the less the flaw detection sensitivity is.

In addition, there is a limit in increasing the magnitude of the magnetization core and the intensity of the current to increase the penetration depth of the magnetic field.

<8>

In the case of a single core, a maximum magnetic flux is generated in the core of the core, and the magnetic sensor saturates first due to the magnetic flux.

<ιο> For reference, there are documents such as JP 1998318988 and KR 20010064351, which have the limitation that the loss inside the conductor can not be accurately measured outside the conductor.

<11>

[Content of invention]

[Technical problem]

The present invention was devised to solve the above problems, and by double the core of the probe part, the strength of the flaw detector can be obtained without increasing the size of the core and obtaining the intensity of the magnetic field even at a low current. Using double core with increased The object is to provide a conductor thickness flaw detector.

<13>

Technical Solution

<14> In order to achieve the above object, the conductor thickness flaw detection apparatus using the heavy core according to the preferred embodiment of the present invention, the non-destructive inspection of the thickness change (thinning) by the corrosion or corrosion of the pipe covered with the insulator And using the eddy currents through the differential probe with double cores to evaluate the loss of the piping outside of the insulator without dismantling the insulator.

<15>

In this case, the probe portion, the eddy current is a fill eddy current, it is preferable that a hall sensor, a GMR (Giant Magnetic Resistance) sensor, or a coil sensor is installed between the cores in the double core.

<17>

Specifically, the present invention, a probe (probe) having a dual core, a drive coil, and a differential Hall sensor; A pillar generation unit connected to the probe unit to generate a broadband pillar voltage applied to the driving coil; An amplifier connected to the probe part to amplify a measurement signal induced by the flow sensor; An A / D converter connected to the amplifier to convert the measurement signal into a digital signal; And a control unit configured to store and display the digital signal while controlling the probe unit, the pillar generation unit, the medium width unit, and the A / D conversion unit.

<19>

Here, the probe portion, the double core consisting of two cores spaced apart from each other; And the driving coils respectively wound around the core, wherein the hall sensor includes: a first hall sensor mounted on a core on an upper joint member connecting upper portions of the two driving coils; and a lower portion of the two driving coils. It is preferred that the teeth are toothed with a second Hall sensor mounted in the center on the lower joint member.

In this case, the core is preferably made of a magnetic permeability magnetic material.

<22>

In addition, it is preferable that the pulse generator generates a square pulse having a pulse width of 20 ysec or more.

In addition, it is preferable that the pillar generating unit adjusts the pillar width from lOysec to 1 msec and the frequency of generation from 100 Hz to 1 kHz. <25>

In addition, the amplifying unit preferably includes a differential amplifying circuit electrically connected to the hall sensor of the probe unit.

<27>

Advantageous Effects

<28> The conductor thickness flaw detection apparatus using a distillation core according to the present invention does not disassemble the insulator by a non-destructive test without changing the thickness caused by the corrosion or corrosion of the pipe covered with the insulator, Through the fill eddy current has the effect of evaluating the loss of the pipe from the outside of the insulator.

<29>

[Brief Description of Drawings]

FIG. 1 is a graph illustrating a calculation of the shape of a single core and the intensity of a magnetic flux generated by the single core.

FIG. 2 is a graph showing the calculation of the shape of the double core and the intensity of the magnetic flux made by the middle core.

3 is a view showing a pipe thinning inspection device using a double core according to a preferred embodiment of the present invention.

Figure 4 is a schematic diagram showing the shape of the probe portion for detecting a thickness change in the insulator on the object to be covered with the insulator in the pipe thinning inspection device using a double core according to an embodiment of the present invention.

FIG. 5 is a differential diagram from the voltage induced in a differential Hall sensor when a pulse voltage generated from a pulls generator is applied to a driving coil surrounding a diversion core in the pipe thinning flaw detector using the dual core of FIG. 4. Graph showing the signal.

6 is a graph showing a signal change of a Hall sensor induced in a test piece according to a change in pulse width in the pipe thinning inspection device using the distillation core of FIG. 4.

FIG. 7 illustrates the variation of the differential signal voltage according to the thickness change of the test piece as the thickness of the insulator changes in the single-core pipe thinning flaw detector. FIG. 8 illustrates a change in the differential signal voltage according to the change in thickness of the test piece as the thickness of the insulator changes in the pipe thinning inspection device using the double core of FIG.

FIG. 9 is a computer screen showing an operation and a flaw detection result of the pipe thinning flaw detector using the double core of FIG. 4. <39>

[Best Mode for Implementation of the Invention]

According to the present invention, the thickness change (decrease) caused by the corrosion or corrosion of the pipe covered with the insulator is not dismantled by non-destructive inspection, and the eddy current is used through the differential probe part having the double cores. Characterized in that configured to evaluate the loss of the pipe from the outside.

<41>

FIG. 1 is a graph showing the shape of a single core and the strength of the magnetic flux produced by a single core, and FIG. 2 is a graph showing the shape of the double core and the strength of a magnetic flux produced by the double core. to be .

Referring to the drawings, the calculation conditions are the same, and the applied current and the number of windings of the driving coil 40 are equal to 1A and 150 turns, respectively.

<44>

In the case of the single core of FIG. 1, the maximum magnetic flux is at the center of the core, and when the hall sensor for defect detection is at the center of the core, the hall sensor has the induced magnetic flux by the driving coil rather than the change of magnetic flux due to the defect. It is much larger so it is harder to detect defects.

<46>

In contrast, in Fig. 2, the maximum magnetic flux is in the core of each core, and the magnetic flux in the place where the defect detection hall sensor 61K62 is located is very small so that the magnetic flux change due to the defect signal can be easily detected. Can be.

<48>

3 is a view showing a pipe thinning inspection device using a distillation core according to a preferred embodiment of the present invention, Figure 4 is an insulator in a pipe thinning inspection device using a double core according to a preferred embodiment of the present invention. Schematic diagram showing the shape of the probe to detect the thickness change inside the insulator on the covered object.

<50>

Referring to the drawings, a probe part for detecting the thickness of the conductor 1 in contact with the conductor 1 to be detected, a pulse generator, an amplification part configured to be electrically connected to the probe part, An A / D converter, and a control unit.

<52>

The probe portion has a dual core 20, a drive coil 40, and a differential Hall sensor.

(61K62). In detail, the probe part includes a double core 20 formed of two cores spaced apart from each other, a driving coil 40 wound around the core, and a hall sensor disposed between the two driving coils 40. 61K62).

<55>

Here, the Hall sensor 61K62 is a first Hall sensor between the two drive coils (40)

61 and the second hall sensor 62 are fixed.

The first hall sensor 61 is an upper joint member connecting the upper portions of the two driving coils 40.

It is mounted in the center on the 51, the second Hall sensor 62 is mounted in the center on the lower joint member 52 connecting the lower portion of the two drive coils (40).

<58>

In addition, the core is preferably made of a high permeability magnetic material.

This probe part is mounted on the insulator (2) surrounding the conductor (1) to perform a measurement operation.

<61>

In addition, the pillar generating unit is connected to the probe unit to generate a broadband pillar current applied to the driving coil 40.

This pillar generating unit generates a square pulse having a pillar width of 20 μ sec or more, adjusts the pillar width from 10 μ sec to 1 msec, and adjusts the frequency of occurrence from 100 Hz to 1 kHz. .

<64>

On the other hand, the differential amplifier unit is connected to the probe portion and the two Hall sensors

(61) configured to amplify the measurement signal induced in (62).

This amplification circuit amplifies the difference between the output voltages of the Hall sensors 61 and 62 applied to the two input terminals. If both input voltages contain in-phase input signals in the in-phase input voltage, the in-phase component on the output side is removed.

<67>

In addition, the A / D conversion unit is connected to the amplifier unit is configured to convert the measurement signal into a digital signal.

In addition, the control unit controls the above-described probe unit, pillar generation unit, amplification unit, and A / D conversion unit, and stores the digital signal converted by the A / D conversion unit and utilizes the display means. Is configured to display.

At this time, the control unit is dedicated for manipulating the components using Lab-View. Windows programs can be utilized.

<71>

[Form for implementation of invention]

According to the present invention, the thickness change (decrease) caused by the corrosion or corrosion of the pipe covered with the insulator, without dismantling the insulator by non-destructive inspection, and the eddy current through the differential probe having a double core Characterized in that configured to evaluate the loss of the pipe from the outside.

<73>

1 is a graph showing the shape of a single core and the strength of the magnetic flux produced by the single core, Figure 2 is a graph showing the shape of the double core and the strength of the magnetic flux generated by the double core to be.

Referring to the drawings, the calculation conditions are the same, and the number of times of applying the applied current and the driving coil 40 is equal to 1A and 150 turns, respectively.

<76>

In the case of the single core of FIG. 1, the maximum magnetic flux is at the core depth, and when the hall sensor for defect detection is located at the center of the core, the hall sensor has the induced magnetic flux by the driving coil rather than the magnetic flux change due to the defect. It is much larger, making it harder to detect defects.

<78>

In contrast, in Fig. 2, the maximum magnetic flux is located at the center of each core, and the magnetic flux at the place where the defect detection hall sensors 61 and 62 are located is very small so that the magnetic flux can be easily changed by the defect signal. Can be detected.

<80>

3 is a view showing a pipe thinning inspection device using a double core according to a preferred embodiment of the present invention, Figure 4 is an insulator in a pipe thinning inspection device using a double core according to a preferred embodiment of the present invention This is a schematic diagram showing the shape of the tube to detect the thickness change inside the insulator on the sensing object covered with.

<82>

Referring to the drawings, a probe part for detecting the thickness of the conductor 1 in contact with the conductor 1 to be detected, a pulse generator, an amplifier part configured to be electrically connected to the probe part, An A / D converter, and a control unit.

<84>

The PTU part has a double core 20, a drive coil 40, and a differential Hall sensor. (61) (62).

In detail, the probe part may include a dip core 20 including two cores spaced apart from each other, a driving coil 40 wound around each of the cores, and a hall sensor 61 disposed between the two driving coils 40. (62).

<87>

Here, the Hall sensors 61 and 62 are the first Hall sensors between the two drive coils 40.

61 and the second Hall sensor 62 are fixed.

It is mounted at the center on the 51, and the second Hall sensor 62 is mounted at the center on the lower joint member 52 connecting the lower portions of the two drive coils 40.

<90>

This probe part is mounted on the insulator (2) surrounding the conductor (1) to perform the measurement.

<93>

In addition, the pulse generator is connected to the probe part to generate a wideband pulse current applied to the driving coil 40.

These pulse generators generate a square pulse with a fill width of 20 μ sec or more, adjust the spread width from 10 y sec to 1 msec, and control the frequency of occurrence from 100 Hz to 1 kHz. do.

<96>

It is configured to amplify the measurement signal induced in (61K62).

This amplification circuit is a circuit for amplifying the difference between the output voltages of the Hall sensors 61 and 62 applied to the two input terminals. If both input voltages contain in-phase input signals in the in-phase input voltage, the in-phase component on the output side is removed.

<99>

and the A / D conversion unit is connected to the amplifying unit to convert the measurement signal into a digital signal.

In addition, the control unit controls the above-described probe unit, pillar generation unit, amplification unit, and A / D conversion unit, and stores the digital signal converted by the A / D conversion unit and displays the display unit. Is configured to display. At this time, the control unit is dedicated for manipulating the components using Lab-View.

Windows programs can be utilized.

<103>

FIG. 5 illustrates a voltage and a differential signal induced in a differential Hall sensor when a pulse voltage generated from a pillar generating unit is applied to a driving coil surrounding a double core in the pipe thinning inspection device using the double core of FIG. 4. 6 is a graph showing a signal change of the Hall sensor induced in the test piece according to the change in the fill width in the pipe thinning inspection device using the double core of FIG.

And, Figure 7 shows a change in the differential signal voltage according to the thickness change of the test piece as the thickness of the insulator, in the pipe thinning flaw detection apparatus consisting of a single core, Figure 8 is a double core In the pipe thinning inspection apparatus using the double core of, the differential signal voltage is shown as the thickness of the test specimen changes as the thickness of the insulator changes.

<106>

Referring to the drawings, it can be seen that the output voltage indicating the sensitivity of the signal was increased more than 20 times and the lift-off was greatly increased compared to the single core.

Therefore, as the pulse width increases, the penetration depth of the eddy current increases, and the pulse eddy current test method can be applied to thicker test specimens, so that the restriction of the test specimen is relatively small in the case of the differential probe portion. .

<109>

<ιιο> FIG. 9 is a computer screen illustrating an operation and a flaw detection result of a pipe thinning flaw detector using the double core of FIG. 4.

<111>

Referring to the figure, the upper figure shows the signal induced from the differential Hall sensor. The middle figure shows the signal strength according to the thickness of the test piece so that the thickness difference of the test piece can be visually checked. In addition, the lower figure shows the signal processing depending on the thickness of the specimen so that the color change can be confirmed.

<113>

Eddy current flaw detection, when the flow of eddy current is affected by blistering, etc., disturbs or changes the direction of eddy current, and the magnetic field of eddy current changes and affects the test coil magnetic field. In addition, the stronger the eddy current, the stronger the system to detect discontinuities. The resulting eddy currents are concentrated by the skin effect near the surface of the circumference of the coil.

According to the formula for the epidermal effect, the eddy current concentrates on the surface root as the frequency increases, and decreases as it goes deeper.

<117>

The penetration depth of the eddy current is given by the following equation.

Where f is the frequency (Ηζ), σ is the conductivity, δ is the penetration depth (m), and μ is the permeability (H / m).

<121>

In the fill eddy current, the frequency is treated twice as the fill width, so the penetration depth increases as the fill width increases.

Therefore, when the differential probe portion is used, the fill width is about 25 times larger than that of the single probe portion, and the penetration depth of the eddy current in the differential probe portion is increased by five times compared to that of the single probe portion.

In addition, the hall sensor of the probe part of the present invention has an advantage of being easy to manufacture in various forms, easy to apply in the field, and appropriately adjust the reception sensitivity.

<125>

As described above, although the present invention has been described by means of a limited embodiment and drawings, the present invention is not limited thereto and is described by those of ordinary skill in the art to which the present invention pertains. Various modifications and variations are possible, without departing from the spirit and scope of the appended claims.

<127>

[Industrial availability]

According to the present invention, a thickness change due to corrosion or corrosion of a pipe covered with an insulator, without dismantling the insulator by a non-destructive test, using a pulsed eddy current through a differential probe section having a double core at the outside of the insulator Since the loss of the pipe can be evaluated, it can be used more effectively in the field of conductor thickness flaw detector.

<129>

Claims

[Range of request]

[Claim 1]

Corrosion or thickness change due to corrosion of the pipes covered by the insulator, with double cores configured to evaluate the loss of the pipe outside of the insulator using eddy currents without dismantling the insulator by non-destructive testing. Differential probe part.

[Claim 2]

In that U term,

The probe portion,

The eddy current is a pulse eddy current, differential probe with a double core, characterized in that a hall sensor, a GMR sensor, or a coil sensor is installed between the core in the double core.

[Claim 3]

The loss of the pipe from the outside of the insulator by using eddy currents through the differential probe with double cores, without dismantling the insulator by corrosion or corrosion of the pipe covered by the insulator, or by removing the thickness by thinning. Pipe thinning inspection device using a double core, characterized in that configured to evaluate the.

[Claim 4]

The method of claim 3,

The probe portion,

The eddy current is a pulse eddy current, pipe thinning inspection device using a double core characterized in that the hall sensor, GMR sensor, or coil sensor is installed between the core in the double core ᅳ

[Claim 5]

A probe part having a dual core, a driving coil, and a differential hall sensor;

A pulse generator connected to the probe part to generate a broadband fill voltage applied to the driving coil;

An amplification section connected to said probe portion for amplifying the measured signal induced in the Hall sensor ^" An A / D converter connected to the amplifier to convert the measurement signal into a digital signal; A control unit configured to store and display the digital signal while controlling the probe unit, the pulse generator, the amplifier, and the A / D converter;

Pipe thinning flaw detection device using a double core, characterized in that it comprises a.

[Claim 6]

The method of claim 5,

The probe portion,

The double core consisting of two cores spaced apart from each other; And

Including; the driving coils respectively wound around the cores;

The Hall sensor is,

A U-hall sensor mounted in the center on the upper joint member connecting the two upper parts of the drive coil, and a second hall sensor mounted in the center on the lower joint member connecting the lower parts of the two driving coils. Pipe Thinning Inspection Device Using Double Core.

[Claim 7]

The method of claim 5,

The core thin-walled flaw detection apparatus using a double core, characterized in that made of a high permeability magnetic material.

[Claim 8]

The method of claim 5,

The pulse generator,

Pipe thinning inspection device using a double core, characterized in that for generating a square pulse having a fill width of 20 μ sec or more.

[Claim 9]

The method of claim 5,

The pulse generator,

The pipe thinning inspection device using a double core, characterized in that the pulse width is adjusted from 10 ysec to 1msec, the frequency of occurrence is adjustable from 100Hz to 1kHz. [Claim 10]

The method of claim 5,

The amplifier,

Pipe thinning inspection device using a double core characterized in that it comprises a differential amplifier circuit electrically connected with the hall sensor of the probe portion.