KR101679520B1 - The defect's the width of a pipe measurement system using multi channel RFECT and measurement method using the same - Google Patents

Abstract

A method for measuring a defect width of a pipe using a multi-channel RFECT according to an embodiment of the present invention includes sensing a change in a magnetic field due to an eddy current change in a pipe at a remote field of a magnetic field through a plurality of coil sensors, A sensing unit for calculating an amplitude value of a direct current component from the sensed signal and detecting an effective coil sensor having an amplitude value exceeding a preset threshold value when the amplitude value is changed, And a control station for calculating the width of the defect by using the information of the overlapped area between the effective coil sensor and the defect occurring in the pipe and the area not overlapped with the defect, the width of the defect can be accurately calculated. As a result, .

Description

Technical Field [0001] The present invention relates to a defect width measurement system for a pipe using a multi-channel RFECT and a measurement method using the same,

TECHNICAL FIELD The present invention relates to a defect width measuring system for piping using a multi-channel RFECT and a measuring method using the same.

Generally, since piping is manufactured using metal, there is a risk of corrosion due to passage of time and external environment. Therefore, it is necessary to periodically check and repair the condition of the piping in order to prevent accidents due to corrosion of the piping. However, when the piping is buried in the ground or the fluid is flowing, it is not easy to conduct the inspection of the piping without detaching or destroying the piping.

To address this situation, remote field eddy current testing may be used to inspect defects inside the piping. The remote field eddy current detection method is a non-destructive inspection method which induces eddy current flow to a test body. Explaining the eddy current detection method, an AC magnetic field is generated when a high frequency voltage is applied to an exciting coil, and an eddy current is generated in a metal material in the magnetic field. The eddy current can be detected by analyzing the sensing signal component output from the coil sensor which senses the change of the eddy current because the state of the eddy current is different due to material, defect, dissimilar metal, shape change and the like.

JP 2002-350406 A

The present invention uses multichannel RFECT which calculates the width of a defect occurring in a piping by using information of an amplitude value calculated based on a sensing signal of a coil sensor and an overlapping area between a coil sensor and a defect of a piping, A defect width measuring system for a pipe and a measuring method using the same.

The fault width measurement system of a pipe using a multi-channel RFECT according to an embodiment of the present invention senses a change in a magnetic field due to an eddy current change in a pipe at a remote field of a magnetic field through a plurality of coil sensors, A sensing unit for calculating an amplitude value of a direct current component from a sensing signal derived in accordance with the sensing signal, and a control unit for determining that a defect has occurred in the pipe when the amplitude value transmitted from the sensing unit is changed, And a control station for calculating the width of the defect using the information of the overlapping region and the overlapping region between the effective coil sensor and the defect occurring in the pipe.

Further, the control station calculates the width of the defect by adding the length of the overlapping area to a value obtained by adding the diameter of the effective coil sensor and the interval between the effective coil sensors.

Further, the length of the concave exclusion region is determined on the basis of the ratio of the amplitude value and the maximum amplitude value of the effective coil sensor overlapping the defects.

Further, the length of the superimposed exclusive area is expressed by the following equation

(W _BL = length of left overlapping exclusion zone, W _BR = length of right overlapping exclusion zone, S _l = diameter of effective coil sensor, R _MAX = maximum amplitude value, R _BL = amplitude value of coil sensor superimposed on left side R _BR = amplitude value of the coil sensor superposed on the right side).

Further, the width of the defect is calculated by the following equation

(W = width of defect, N _valid = number of effective coil sensors, S _l = effective coil sensor diameter, W _int = gap between effective coil sensors, W _BL = length of left overlapping region, W _{BR =} The length of the exclusion area).

The threshold value is an amplitude value of the coil sensor in contact with the boundary of the defect.

Also, the threshold value may be expressed by the following equation

(W _T = threshold value, a = first order coefficient, b = second order coefficient, c = third order coefficient, Le = length from the center of the defect to the center of the coil sensor tangent to the boundary of the defect).

A method for measuring a defect width of a pipe using a multi-channel RFECT according to an embodiment of the present invention includes sensing a change in a magnetic field due to an eddy current change in a pipe at a remote field of a magnetic field through a plurality of coil sensors, Calculating an amplitude value of a direct current component from a sensing signal derived in accordance with a predetermined threshold value and determining whether a defect has occurred in the pipe when the amplitude value is changed, And a defect detecting step of calculating the width of the defect using the information of the overlapping area and the overlapping area between the effective coil sensor and the defect occurring in the pipe.

The defect detection step may further include determining that the detected coil corresponds to the effective coil sensor when the detected amplitude value has an amplitude value exceeding the threshold value. Calculating a length of the overlapping region based on a ratio of an amplitude value and a maximum amplitude value of an effective coil sensor superimposed on the defect, calculating a length of the overlapping region by a value obtained by adding a diameter and an interval of the effective coil sensor, And calculating the width of the defect by subtracting the width of the defect.

Also, the threshold value may be expressed by the following equation

(W _T = threshold value, a = first order coefficient, b = second order coefficient, c = third order coefficient, Le = length from the center of the defect to the center of the coil sensor tangent to the boundary of the defect).

Further, the length of the superimposed exclusive area is expressed by the following equation

(W _BL = length of left overlapping exclusion zone, W _BR = length of right overlapping exclusion zone, S _l = diameter of effective coil sensor, R _MAX = maximum amplitude value, R _BL = amplitude value of coil sensor superimposed on left side R _BR = amplitude value of the coil sensor superposed on the right side).

Further, the width of the defect is calculated by the following equation

(W = width of defect, N _valid = number of effective coil sensors, S _l = effective coil sensor diameter, W _int = gap between effective coil sensors, W _BL = length of left overlapping region, W _{BR =} The length of the exclusion area).

The defect width measuring system of a pipe using a multi-channel RFECT according to an embodiment of the present invention can detect an effective coil sensor by using an amplitude value of a coil sensor. The diameter of the effective coil sensor and the distance between each effective coil sensor It is possible to calculate the width of the defect and improve the reliability of the pipe inspection result.

Further, in calculating the width of the defect, the length of the non-overlapping non-overlapping area with the defect is calculated based on the ratio of the maximum amplitude value and the amplitude value of the coil sensor superimposed on the defect, The accuracy of the defect width calculation process can be secured.

1 is a block diagram of a defect width measurement system for a pipe using a multi-channel RFECT according to an embodiment of the present invention.
FIG. 2 (a) is a view showing the positions of the exciting coil and the coil sensor in the piping. FIG. 2 (b) shows a magnetic field induced by the exciting coil in the pipe and a coil sensor Fig.
3 is a block diagram of a sensing signal processing module according to an embodiment of the present invention.
4A is a graph showing a phase component value X as an output value of a sensing signal processing module according to an embodiment of the present invention. Is a graph showing the phase difference value?.
5 (a) is a view showing the position of movement of a coil sensor and the position of a defect at the time of inspecting a pipe. FIG. 5 (b) is a graph showing a change in amplitude value corresponding to each coil sensor with time. 5C is a graph showing the amplitude values of the coil sensors at the time when the coil sensor passes the defect, for each coil sensor.
FIG. 6 is a cross-sectional view of the coil sensor and defects viewed from the direction A-A 'shown in FIG. 5 (a).
7 is a diagram showing the diameter of the coil sensor, the gap between the coil sensors, and the area not overlapping the defect.
8 is a flowchart of an inspection method using a defect width measurement system for pipes using a multi-channel RFECT according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements have the same numerical numbers as much as possible even if they are displayed on different drawings. Also, the terms "one side," " first, "" first," " second, "and the like are used to distinguish one element from another, no. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the accompanying drawings, a description will be made in detail of a system for measuring a defect width of a piping using a multi-channel RFECT of a pipeline 1 of the present invention and a method of measuring the same.

1 is a block diagram of a defect width measuring system for a pipe using a multi-channel RFECT according to an embodiment of the present invention. As shown in FIG. 1, the present invention includes a control station 300, a sensing unit 100, A board 200, an odometer 231, a motor 271, a battery 411, and a power board 400.

The sensing unit 100 senses a change in a magnetic field due to an eddy current change in the pipe 1 in a remote field of a magnetic field through a plurality of coil sensors 111 and generates a sensing signal V _S (R) and a phase difference value (?) Of the direct current component from the main body (200). The sensing unit 100 includes an exciter module 120 and a sensing module, and a detailed description thereof will be described later.

The control station 300 determines that a defect has occurred in the pipe 1 when the amplitude value R is changed. It is also possible to detect the effective coil sensor 111 having the amplitude value R exceeding the predetermined threshold W _T and to detect the information of the overlapping area between the detected effective coil sensor 111 and the defect The width of the defect inside the pipe 1 is calculated.

The control station 300 includes first and second control servers 301 and 302. The first control server 301 controls the operation of the fault width measurement system of the pipe using the multichannel RFECT based on the state change information in the pipe 1 and the second control server 302 controls the operation of the pipeline defect width measurement system using the amplitude value R And the phase difference value [theta], the defect size and the generated position are calculated.

The power board 400 supplies power necessary for driving a defect width measuring system of a pipe using a multi-channel RFECT, and includes a DC / DC converter 410 and a protection circuit 420. The DC / DC converter 410 converts the voltage of the battery 411 into a voltage of a predetermined magnitude. The protection circuit 420 protects the power board 400 from sparks generated by a short or the like, And supplies the voltage to the main board 200.

The main board 200 controls a device connected to the main board 200 or receives information generated in the device. For example, the main board 200 may transmit the amplitude value R and the phase difference value? To the control station 300 through the communication module 210, and may transmit the amplitude value R and the phase difference value? The motor 271 can be controlled. Also, the driving distance information is received from the odometer 231, and the driving power is supplied from the power board 400.

The mainboard 200 includes an interface corresponding to each device for controlling connected devices or transmitting and receiving information. For example, the odometer interface 230 is connected to the odometer 231 to transmit driving distance information to the main controller 240. The motor interface 270 receives the control signal of the motor controller 260, (271). The sub-interface 250 receives the amplitude value R and the phase difference value? Calculated from the sub-controller 114. In addition, the mainboard 200 may include a memory 220 for storing data

Hereinafter, the principle that the amplitude value R is calculated through the sensing module and the exciter module 120 included in the sensing unit 100 will be described in detail with reference to FIGS.

The sensing module detects a change in the magnetic field in the remote field to generate a sensing signal Vs and calculates an amplitude value R and a phase difference value? Based on the sensing signal Vs. The sensing module includes a plurality of coil sensor modules 110. The coil sensor module 110 includes a coil sensor 111, a main interface 115 for transmitting and receiving signals to and from the main board 200, a coil sensor 111, of the sensing signal (V _S), the sensor interface 112 and the received sensing signal (V _S), AD converter 113 for converting into a digital signal form of the amplitude value (R) and the retardation value (θ) for receiving a And a subcontroller 114 for operating.

The exciter module 120 includes a sine wave generator 121 for generating an AC signal based on the reference signal V _R , an exciting coil 123 for operating the exciting coil 123 based on the AC signal input from the sine wave generator 121 123) driver 122, and an exciting coil 123 for forming an alternating magnetic field inside the pipe 1.

2 (a) is a view showing the positions of the exciting coil 123 and the coil sensor 111 when inspecting the pipe 1. FIG. 2 (b) is a view showing the position of the exciting coil 123 in the pipe 1, And a coil sensor 111 for sensing the magnetic field. The process of generating the sensing signal V _S with reference to FIG. 2 will be described.

As shown in FIG. 2 (a), the exciting coil 123 and the coil sensor 111 are inserted into the pipe 1 and are spaced apart from each other by a predetermined distance. In order to inspect the pipe 1, While moving in the axial direction (X-axis direction).

2B, the exciting coil 123 receives the reference signal V _R under the control of the reference signal generator 280 of the main board 200, and outputs the reference signal V _R V _R ), an AC magnetic field is formed inside the pipe 1. The AC magnetic field directly in the direction (X axis direction) toward the coil sensor 111 is present in the direct coupling zone, but gradually decreases as the distance increases and is not present in the remote field . However, the alternating magnetic field directed in the direction (Z-axis direction) toward the wall surface of the pipe 1 generates an eddy current on the surface of the pipe 1 formed of the ferromagnetic material and flows along the wall surface of the pipe 1. The generated eddy current generates a magnetic field near the coil sensor 111. Magnetic field is also changed according to the eddy current induced by the eddy currents, because, since the coil detects the sensor 111 and generates a sensing signal (V _S) that contains information about the change in thickness.

FIG. 3 is a block diagram showing a sensing signal processing module 114 according to an embodiment of the present invention. A process of calculating the amplitude value R and the phase difference with reference to FIG. 3 will be described. The sensing signal processing module 114 includes a reference signal output section 114a, a frequency synthesizing section 114b, a filter section 114c, and an amplitude phase calculating section 114d.

The sensing signal V _S output from the coil sensor 111 is

, And the reference signal V _R

. The sensing signal V _S is converted into a digital signal by passing through a filter 112a for removing noise, an amplifier 112b for amplifying the signal amplitude, and an A / D converter 113. The sensing signal V _S is then input to the first frequency synthesizer 114b1 and the second frequency synthesizer 114b2. The reference signal V _R is input to the phase locked loop 114a1 and the phase shifter 114a2 to precisely adjust the phase and the phase shifter 114a2 receives the first reference signal V _R1 ,

). The first reference signal V _R1 is then input to the first frequency synthesizer 114b1. The second reference signal V _R2 input to the second frequency synthesizer 114b2 at this time corresponds to a signal that the first reference signal V _R1 has passed through the 90 phase shifter 114a3,

.

The first frequency synthesizer 114b1 synthesizes the first reference signal V _R1 and the sensing signal Vs and outputs a first synthesized signal V _{M1 as} shown in Equation 1 below. The second frequency synthesizer 114b2 synthesizes the second reference signal V _R2 and the sensing signal Vs and outputs a second synthesized signal V _{M2 as} shown in Equation 2 below.

[Equation 1]

&Quot; (2) "

Next, the first low-pass filter 114c1 extracts the direct-current component from the first composite signal V _{M1 and} outputs the phase component value X,

And the second low-pass filter 114c2 extracts the direct current component from the second synthesized signal V _{M2 and} outputs the quadrature component value Y,

.

Finally, the amplitude phase calculator calculates the amplitude value R using the phase component value X and the quadrature component value Y according to the following equation:

And a phase difference value?

Can be calculated.

The at least one sensing signal processing module 114 may be implemented as a digital circuit in the sub-controller 114, which may be a multi-channel Lock-In Amplifier chip Lt; / RTI > The sub-controller 114 may include algorithms for performing the functions described above, and may be implemented in firmware, software, or hardware (e.g., a semiconductor chip or an application-specific integrated circuit).

A process of determining the length L and the depth D of the defect in the control station 300 will be described with reference to FIGS. 4A and 4B. FIG. 4A is a graph showing a phase component value X, and FIG. 4B is a graph showing a phase difference value.

The abscissa of the graph shown in FIG. 4 (a) represents the moving distance of the pipe 1 in the longitudinal direction, and the ordinate represents the phase component value X. However, the phase component value (X) is represented by the magnitude of the voltage. As shown in FIG. 4 (a), d ₁ is a horizontal axis value at a point where the phase component value X is the maximum, and d ₂ is a horizontal axis value at a point where the phase component value X is the minimum. x is a difference value between d ₂ and d ₁ , which represents the distance traveled in the axial direction of the coil sensor 111 in the pipe 1. Based on this, the length L of the defect can be estimated through the following equation (3).

&Quot; (3) "

(L: length of a _{defect, x = d 2 -d 1,} w 1, w 2 = experimental value, C = experimental value)

The horizontal axis of the graph shown in FIG. 4 (b) is the phase component value (X), and the vertical axis indicates the quadrature component value (Y). When the phase component value X and the quadrature component value Y are represented by coordinate points X and Y in accordance with the passage of time, if there is a defect in the pipe 1, the coordinate point is deviated from the vicinity of the origin, As shown in Fig. The angle formed by the path of the coordinate point and the X axis is defined as &thetas;

And represents the phase difference between the sensing signal V _S and the reference signal V _R. the depth D of the defect can be estimated based on the following equation (4).

&Quot; (4) "

(D: depth of defect,?: Phase difference value)

Hereinafter, a method for calculating the width of defects will be described in detail with reference to FIGS. 5 to 7. FIG. 5A is a view showing the movement positions and the positions of defects of the coil sensors 111.1 to 111.7 when inspecting the piping 1 and FIG. 5B is a diagram showing the correspondence between the coil sensors 111.1 to 111.7 Of the amplitude value (R). 5C is a graph showing amplitude values R of the coil sensors 111.1 to 111.7 for each of the coil sensors 111.1 to 111.7 when the coil sensors 111.1 to 111.7 pass the defect. 6 is a cross-sectional view of the defects and the coil sensors 111.1 to 111.7 seen from the direction A-A 'shown in FIG. 5 (a). 7 is a diagram showing a diameter S _{l of the} coil sensors 111.1 to 111.7, a gap W _int between the coil sensors 111.1 to 111.7, and a region not overlapping the defect.

Since the first and seventh coil sensors 111.1 and 111.7 shown in FIG. 5A are defective (see FIG. 6D), there is no overlapping area. The amplitude values R1 and R7 based on the sensing signal V _S of the first and seventh coil sensors 111.1 and 111.7 do not change (see FIG. 5 (b)) and are used to calculate the defect width It does not.

The second and sixth coil sensors 111.2 and 111.6 shown in FIG. 5A move while touching the interface of the defect at the time of inspection of the pipe 1 (see FIG. 6C). As shown in the graph of FIG. 5B, the amplitude values R2 and R6 based on the sensing signal V _S of the second and sixth coil sensors 111 change at the time of passing the defect.

Here, the amplitude value R of the second and sixth coil sensors 111.2 and 111.6 corresponds to a threshold value W _T (see FIG. 5C) and is determined by the following expression (5) do. The following coefficients (a = first order coefficient, b = second order coefficient, c = third order coefficient) are values determined according to the pipe thickness, diameter, Also, as shown in FIG. 6 (c), Le means the length from the center of the defect to the center of the coil sensor in contact with the boundary of the defect.

&Quot; (5) "

((C) of the W _T = threshold value, a = 1-th order coefficient, b = 2-th order coefficient, c = 3-th order coefficient, Le = length, 6 from the center of the defect center of the coil sensor in contact with the perimeter of the defect Reference )

The threshold value (W _T), the amplitude value that is used to detect the effective coil sensor 111's to estimate the width of a defect, specifically, the control station 300 has exceeded the threshold value (W _T) (R) The coil sensor 111 having the coil sensor 111 is regarded as the effective coil sensor 111. The control station 300 also counts the number of valid coil sensors 111 detected (N _valid ). 5 (a), the amplitude values R3 to R5 of the third to fifth coil sensors 111.3 to 111.5 correspond to the amplitude values R2 and R6 of the second and sixth coil sensors The third to fifth coil sensors 111.3 to 111.5 correspond to the effective coil sensors 111 and the number N _valid of the effective coil sensors 111 is equal to 3.

The third and fifth coil sensors 111.3 and 111.5 shown in FIG. 5A move while defects and some areas are superimposed upon inspection of the pipe 1 (see FIG. 6A). As shown in the graph of FIG. 5B, the amplitude values R3 and R5 based on the sensing signal V _S of the third and fifth coil sensors 111.3 and 111.5 change at the time of passing the defect And has a larger value than the amplitude values R2 and R6 of the second and sixth coil sensors 111.2 and 111.6 (see (b) and (c) of FIG. 5).

Here, in order to accurately calculate the width of the defect, it is necessary to consider the length of the non-overlapping region between the third and fifth coil sensors 111.3 and 111.5 and the defect. 5 (b) and 5 (c), the amplitude value R of the coil sensor 111 varies with the length of the overlap region between the defects. Therefore, the length W _{BL ,} W _BR ) can be calculated. That is, the lengths (W _{BL ,} W _BR ) of the overlapping area are set to the ratio of the amplitude values (R 3, R 5) and the maximum amplitude value (R _MAX ) of the third and fifth coil sensors And is accurately determined by the following expression (6).

&Quot; (6) "

(W _BL = length of left overlapping exclusion zone, W _BR = length of right overlapping exclusion zone, S _l = diameter of effective coil sensor, R _MAX = maximum amplitude value, R _BL = amplitude value of coil sensor superimposed on left side R _BR = Amplitude value of the coil sensor superimposed on the right side)

The fourth coil sensor 111.4 shown in FIG. 5 (a) moves while defects and all areas are superimposed upon inspection of the pipe 1 (see FIG. 6 (b)). As shown in the graph of FIG. 5B, the amplitude value R4 of the fourth coil sensor 111 largely changes at the time of passing the defect, and has the largest amplitude value R _MAX . (See Figs. 5 (b) and 5 (c)). Therefore, the amplitude value R4 of the fourth coil sensor 111 is the maximum amplitude value R _{MAX ,} and is used to calculate the lengths W _{BL and} W _BR of the above-mentioned overlapping area.

7 is a diagram showing a diameter S _{1 of the} coil sensor 111, a gap W _int between the coil sensors 111 and an area not overlapping the defect, where W indicates the width of the defect , W _BL, and W _BR denote the length of the superimposed area. In addition, S ₁ denotes the directivity of the effective coil sensor 111, and W _int denotes the interval between the coil sensors 111.

7, the width of the defect is the diameter S ₁ of the effective coil sensor 111. The distance W _int between the effective coil sensors 111, and the lengths W _{BL and} W _BR of the overlapping area. That is, the width of the defect (W _{BL ,} W _BR ) is calculated by adding the diameter S ₁ of the effective coil sensor 111 and the distance W _int between the effective coil sensors 111, can do. This can be expressed by the following equation (7).

&Quot; (7) "

(W = width of defect, N _valid = number of effective coil sensors, S _l = diameter of effective coil sensor, W _int = gap between effective senec coil, W _BL = length of left overlapping region, W _{BR =} The length of the exclusion zone)

The number of effective coil sensors 111 can be counted by comparing each amplitude value R at the control station 300 with a threshold value W _T. The diameter S ₁ and the distance W _int of the effective coil sensor 111 correspond to predetermined values in manufacturing a defect width measuring system for a piping using a multichannel RFECT and the length W _BR , W _BL ) can be calculated through Equation (6). Therefore, the defect width of the pipe 1 can be calculated by substituting the above-described values into the equation (7).

Hereinafter, a method using a fault width measurement system for pipes using a multi-channel RFECT according to an embodiment of the present invention will be described with reference to FIG. In the following description, the same or similar descriptions as those described above are omitted or briefly described.

First, the change in the magnetic field induced by the eddy current formed in the remote field of the pipe 1 is sensed through the plurality of coil sensors 111 (S110). The coil sensor 111 generates a sensing signal V _S reflecting the change of the magnetic field and transmits the sensing signal V _S to the sensing signal processing module 114. The sensing signal processing module 114 uses the equations 1 and 2 The phase component value (X)

And the quadrature phase component value (Y)

. The sensing signal processing module 114 then calculates the amplitude value R based on the phase component value X and the quadrature phase component Y,

And a phase difference value?

(S120).

Next, the control station 300 having received the amplitude value R detects the valid coil sensor 111 by comparing it with a predetermined threshold value Wt (S130). Specifically, the coil sensor 111, the amplitude value (R) in this case exceeds a threshold (W _T) determined to correspond to effective coil sensor 111, and the threshold value (W _T) is the equation (5) below the .

&Quot; (5) "

((C) of the W _T = threshold value, a = 1-th order coefficient, b = 2-th order coefficient, c = 3-th order coefficient, Le = length, 6 from the center of the defect center of the coil sensor in contact with the perimeter of the defect Reference)

Next, the control station 300 can calculate the lengths W _BR and W _BL of the superimposed area on the basis of the ratio of the maximum amplitude value R and the amplitude value R of the superposed coil sensor 111. The lengths (W _BR , W _BL ) of the overlapping area may be specified by Equation (6) below (S140)

&Quot; (6) "

(W _BL = length of left overlapping exclusion zone, W _BR = length of right overlapping exclusion zone, S _l = diameter of effective coil sensor, R _MAX = maximum amplitude value, R _BL = amplitude value of coil sensor superimposed on left side R _BR = Amplitude value of the coil sensor superimposed on the right side)

Finally, the diameter (S _l), the effective coil sensor 111 intervals (W _int) the length of the overlapped negative region (W _BR, W _BL) to the adding value between the width of the defect is effective coil sensor 111, the (S150). This can be expressed in the following Equation (7).

&Quot; (7) "

(W = width of defect, N _valid = number of effective coil sensors, S _l = diameter of effective coil sensor, W _int = gap between effective senec coil, W _BL = length of left overlapping region, W _{BR =} The length of the exclusion zone)

While the present invention has been described in detail with reference to the specific embodiments thereof, it is to be understood that the present invention is not limited to the details of the present invention, It will be apparent that the present invention is not limited thereto and that variations and modifications may be made by those skilled in the art within the technical scope of the present invention.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: Piping 10: Fault Width Measurement System for Piping Using Multi-Channel RFECT
100: sensing unit 110: coil sensor module
111: coil sensor 112: sensor interface
112a: filter 112b: amplifier
113: A / D converter 114:
114z: sensing signal processing module 114a: reference signal output section
114a1: phase locked loop 114a2: phase shifter
114a3: 90 占 phase shifter 114b: frequency synthesizer
114b1: first frequency synthesizer 114b2: second frequency synthesizer
114c: a filter unit 114c1: a first low-pass filter
114c2: a second low-pass filter 114c3: a first offset eliminator
114c4: second offset eliminator 114d: amplitude phase calculator
115: Main interface 120: Exciter module
121: Sinusoidal wave generator 122: Exciting coil driver
123: Exciting coil 200: Main board
210: communication module 220: memory
230: odometer interface 231: odometer
240: main controller 250: sub-interface
260: motor controller 270: motor interface
271: Motor 280: Reference signal generator
300: Control station 310: First control server
320: second control server 400: power board
410: DC / DC converter 411: Battery
420: Protection circuit N _valid = Number of effective coil sensors
V _S : sensing signal V _R : reference signal
V _R1 : first reference signal V _R2 : second reference signal
V _M1 : first synthesized signal V _M2 : second synthesized signal
R: amplitude value?: Phase difference value
W: Width of defects S _{l :} Diameter of effective coil sensor
W _{int :} interval between effective senge coil W _{BL ;} Length of left overlapping exclusion area
W _{BR :} length of right overlapping exclusion area R _{MAX :} maximum amplitude value
Le: Length from the center of the defect to the center of the coil sensor corresponding to the boundary of the defect

Claims (12)

A sensing unit that senses a change in a magnetic field due to an eddy current change inside the pipe in a remote field of an alternating magnetic field through a plurality of coil sensors and calculates an amplitude value from a sensing signal induced according to the change in the magnetic field; And
Detecting an effective coil sensor having an amplitude value exceeding a predetermined threshold value when it is determined that a defect has occurred in the pipe when the amplitude value transmitted from the sensing unit is changed, And a control station for calculating a width of the defect by subtracting the length of the overlapping region where the effective coil sensor and the pipe defect do not overlap the value obtained by adding the interval between the coil sensors, Defect Width Measurement System for Piping.
delete Claim 1
The length of the superimposed exclusive area is
An amplitude value of an effective coil sensor located at both ends of the effective coil sensors and overlapping only a partial region with the defect and a maximum amplitude value of an effective coil sensor which is located at the center among the effective coil sensors, The system for measuring defect width of a pipe using a multi-channel RFECT is determined based on the ratio of the number of defects.
Claim 3
The length of the superimposed exclusive area is expressed by the following equation

(W _BL = length of left overlapping exclusion zone, W _BR = length of right overlapping exclusion zone, S _l = diameter of effective coil sensor, R _MAX = maximum amplitude value, R _BL = amplitude value of coil sensor superimposed on left side, R _BR = Amplitude value of the coil sensor superposed on the right side)
Defect Width Measurement System for Piping Using Multi - Channel RFECT.
The method of claim 4,
The width of the defect is expressed by the following equation

(W = width of defect, N _valid = number of effective coil sensors, S _l = effective coil sensor diameter, W _int = gap between effective coil sensors, W _BL = length of left overlapping region, W _{BR =} The length of the exclusion zone)
Defect Width Measurement System for Piping Using Multi - Channel RFECT.
The method according to claim 1,
Wherein the threshold value is an amplitude value of a coil sensor in contact with the boundary of the defect.
The method of claim 6,
The threshold value is calculated by the following equation

(W _T = threshold, a = first order coefficient, b = second order coefficient, c = third order coefficient, Le = length from the center of the defect to the center of the coil sensor tangent to the boundary of the defect)
Defect Width Measurement System for Piping Using Multi - Channel RFECT.
Sensing a change in a magnetic field due to an eddy current change in a pipe in a remote field of a magnetic field through a plurality of coil sensors and calculating an amplitude value of a direct current component from a sensing signal induced according to the change in the magnetic field; And
Detecting an effective coil sensor corresponding to an amplitude value exceeding a predetermined threshold value and determining an interval between the diameter of the effective coil sensor and the effective coil sensor And a defect detection step of calculating a width of the defect by subtracting the length of the overlapping region where the pipe defect does not overlap the effective coil sensor with the value of the defect width Way.
The method of claim 8,
The defect detection step
Determining that the detected value corresponds to the effective coil sensor when the detected amplitude value has an amplitude value exceeding the threshold value;
An amplitude value of an effective coil sensor located at both ends of the effective coil sensors and overlapping only a partial region with the defect and a maximum amplitude value of an effective coil sensor which is located at the center among the effective coil sensors, Calculating a length of the overlapping area based on a ratio of the length of the overlapping area; And
And calculating a width of a defect by adding the length of the effective coil sensor and the interval plus the length of the overlapping region.
The method of claim 9,
The threshold value is calculated by the following equation

(W _T = threshold, a = first order coefficient, b = second order coefficient, c = third order coefficient, Le = length from the center of the defect to the center of the coil sensor tangent to the boundary of the defect)
A method for measuring a defect width of a pipe using a multi-channel RFECT.
Claim 9
The length of the superimposed exclusive area is expressed by the following equation

(W _BL = length of left overlapping exclusion zone, W _BR = length of right overlapping exclusion zone, S _l = diameter of effective coil sensor, R _MAX = maximum amplitude value, R _BL = amplitude value of coil sensor superimposed on left side R _BR = Amplitude value of the coil sensor superimposed on the right side)
A method for measuring a defect width of a pipe using a multi-channel RFECT.
The method of claim 9,
The width of the defect is expressed by the following equation

(W = width of defect, N _valid = number of effective coil sensors, S _l = effective coil sensor diameter, W _int = gap between effective coil sensors, W _BL = length of left overlapping region, W _{BR =} The length of the exclusion zone)
A method for measuring a defect width of a pipe using a multi-channel RFECT.

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